米尔恩精选(九篇)
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第1篇：米尔恩范文
在米其林的产品序列里，Enegry XM2为中档舒适型轮胎，定位比前年上市的Primacy LC博悦略低，主要适配中档家用及公务车。从目前其提供的规格也可看出，13～16英寸共26个规格基本满足了5万～30万元轿车的需求。
为中国市场定制
近些年，国内车市格外繁荣，已经占据全球头把交椅，但道路状况却一直不太乐观，发展也严重滞后。就拿我自己的亲身经验来说，自驾车上4条跑了不到两万公里的欧系运动型轮胎，已经有1条侧壁鼓包，彻底报废，还有两条扎了钉子，做过内补，只剩下1条尚且完好。说实话，我这还算是在意的呢。因此，针对中国道路状况而设计的轮胎就显得尤为重要，所以我比较看好米其林Enegry XM2韧悦。
据一项调查显示，80％的中国用户将安全性列为使用轮胎时的首要考虑。其中又有约60％(即近半数参与调查的用户)认为，坚韧性是与安全性有关的最重要的轮胎特征。作为“韧”二代的米其林EnegryXM2韧悦，自然背负着这样的使命，为注重行车安全的车主而设计，充分了考虑中国路况与气候状况、整车配备和车主驾驶习惯等因素，在确保坚韧性的同时，还缩短了制动距离，增加了行驶里程。
“悦”：更抓地
我们选取了规格为205／55 R16 91V的米其林Enegry XM2韧悦进行专业测试，看看它是不是名副其实的“韧”二代。虽然测试胎是国内最常见的规格，但目前依然是进口，原产地为橡胶资源极为丰富的泰国。
其制造工艺良好，胎面加工时产生的“毛须”已被处理。纵向主排水沟槽只有3条，但棱角清晰可见，在四个固定检测点上测得的深度基本在7.51mm左右，均匀度很好。常温(25℃)下，胎面橡胶块硬度约73HA，比一般运动型轮胎要软。单胎重量仅为10.08kg，在同规格轮胎中属中等偏轻的，因此会有较好的经济性和操控性。
我们选择的测试车为常见的家用A级车――一汽－大众速腾1.8T自动挡。与一般家用车相比，速腾的老款1.8T发动机具有较大的爆发力，且最大扭矩持续时间较长，对轮胎的抓地力要求很高。此车原配轮胎规格即为205／55 R16，因此可以有明显的对比。米其林Energy XM2韧悦的抓地力等级(Traction)为A级，达到了舒适型轮胎的最高水平，但在全油门起步时也难免出现打滑。对于驾驶风格比较粗犷的人来说，使用225／45 R17的运动型轮胎可能更为合适。
客观地说，作为一款中档舒适型轮胎，米其林Energy XM2韧悦已经具备了相当不俗的驾驶乐趣――一方面是抓地力更好，另一方面是行驶噪声更低。
在冷胎(30.2℃)状态下，我们累计进行300m的绕桩，测试轮胎进入了工作状态，胎面橡胶硬度降至66HA。在转向进桩时，前轮没有明显侧滑，ESP系统没有介入，随着车速的逐渐提升，仪表上的ESP指示灯开始偶尔闪烁，但没有明显的转向不足，说明米其林Enegry XM2韧悦的抓地性能不错。
毫无疑问，米其林Enegry XM2韧悦中的高弹性胎面橡胶，对增强轮胎的适应能力功不可没。在采用复合材料之后，其胎面便能与最细小的不规则路面贴合，在变形时更加柔韧，由此提供更充分的抓地力。
从花纹上也可以看出，作为一款中档舒适型轮胎，米其林Enegry XM2韧悦使用的却是更高级别的非对称花纹，因此内外侧花纹的针对性能更强、分工更为明确。乍看上去，其两侧花纹几乎相同，但细看之后，却另藏玄机。
就拿胎肩花纹块来说吧，两侧的大小相近，且花纹块之间都设计有支撑，防止过度的变形，确保操控性，但外侧并没有纵向的细小沟槽，即便是横向细小沟槽也没有贯穿到底，因此刚性要强于内侧，从而提供了更好的弯道抓地力。
对内侧花纹来说，直线行驶的抓地与排水则是其主要职能。在干燥地面上，米其林Enegry XM2韧悦的100km／h-0制动距离为39.37m，而原配轮胎为41.25m，相差达1.88m。虽然我们没有做专业的湿地测试，但今年北京各外频繁的强降雨给了我们更多主观体验的机会。由于新胎的缘故，花纹沟槽较深，其排水能力，特别是在积水路面上的抗滑水表现，要比速腾的原配轮胎更好出不少。
“韧”：更耐用
在将近1000km的综合测试之后，我们又对米其林Enegry XM2韧悦的主排水沟槽深度进行了测试，结果平均值为7.44mm，减少了不到1％。以磨损到1.6mm为基准，预计行驶里程将超过80000km，可谓名副其实的“经久耐用”。
不过，在此我们也提醒您，如果您所在的地区降水量多的话，无论您用的是哪类轿车轮胎，更换轮胎的标准要从沟槽深度1.6mm提升至4mm，以确保足够的湿地抓地力。不过即便如此，米其林Enegry XM2韧悦依然可以提供至少50000km的安全旅程。
测试过程中，我们还特意选取了一些粗糙或者有碎物的路面，米其林Enegry XM2韧悦安然无恙，比我的那套运动型轮胎皮实了不少，体现了其坚韧的一面。而这种坚韧，主要得益于米其林的IRONFlex技术――既为轮胎侧壁带来高强度和牢固性，又能够实现高弹性和灵活性，从而可以出色地应对各种相糙的路面，且耐用性也更好。
第2篇：米尔恩范文
【Key words】similarity； difference； onomatopoeia
Onomatopoeia originates from a word of Greek onomatopoeia， which means that the appearance of words comes from the imitation of the sound given out from some object or movement， or at least has some connection with it. There are some differences in applied scope between English and Chinese onomatopoeia， and they each have their common usage.
On the one hand， there are similarities of English and Chinese onomatopoeia. In the first place， they have similar rhetorical function. No matter English or Chinese onomatopoeia， it is a means of word-building as well as an important rhetorical means， making people feel as if they are participating and hearing. In the second place， the characteristics of absolute structure are similar. The same things in nature and human’s common feeling make different nation’s language have same onomatopoeia. Some of them are very obvious such as baba （papa）， mama （mamma）， ping pang （ping pong）， pipa （pitpat）， dingdong （dingdong）， and ha-ha （ha-ha）. In addition， they often appear in over lapping sound. In mutual translation of English and Chinese， we only need to translate the onomatopoeia which is used as independent component in original sentence into the corresponding one in target language. For example：
（1）妈妈， 我回来了！Mamma！ I’m home now.
（2）叮咚！叮咚！泉水在不停得流淌着。Dingdong！ Dingdong！ The spring is flowing.
On the other hand， there are differences of English and Chinese onomatopoeia. Firstly， we can see the differences in syntactic function. English onomatopoeia is much more active than Chinese onomatopoeia， and it is used more widely. The most obvious aspect is that it has more syntactic functions than Chinese onomatopoeia. Most of them are verb and noun， and used as subject， predicate and object， while most Chinese onomatopoeia only has the nature of adjective， and it is mostly used as attribute and adverbial， sometimes predicate. For example （Leki 117）， The beam sinks earthwards， taut and protesting， its creaks blending with the squeaking and rumbling of the grinding-wheels and the occasional grunts and signs of the camels. 大梁压向地面， 绞紧了绳子， 发出吱吱嘎嘎与磨滚的轧轧隆隆声， 以及骆驼偶尔发出的呼噜叹息声响成了一片。
Secondly， the motivation of using onomatopoeia is also different. From the point of the inner organization of it， language is a kind of sign system. Every sign has two aspects： use what to show and to show what， which are style and content of sign. We have two kinds of it： direct onomatopoeia and indirect onomatopoeia. The former one can arise the association between sound and meaning because they are quite similar. Chinese onomatopoeia often copy sounds directly， which belongs to direct onomatopoeia while English onomatopoeia usually use some verbs and nouns to describe sounds belongs to indirect onomatopoeia. For Example：
（1）雨吧哒吧哒地落在屋顶上。The rain patters on the roof.
（2）她们叽叽喳喳地说话。They spoke in whispers.
Thirdly， there are also some changes in usage. Dog’s signified meanings in English and Chinese language do not have substantial difference， but they are very different in the intensive meaning. In western countries， dogs are people’s pets. They take dogs as companion and friends. While in China， the treatment the dogs receive is quite different. They are usually kept for watching the house， and they are human’s servants. From the English idiom “Love me， love my dog.” And the Chinese one “gou ji tiao qiang” （a cornered dog will do something desperate）， we can get a hint of different cultures. In addition， in English the same word for expressing animals’ sound can be used for different animals. For example， “howl” can be used for lions， tigers， jackals and wolves at the same time； while in Chinese animals’ sound is basically one for one. For example， gou fei， lang hao， he li， que zao， ma si， hu xiao， shi hou， niao zhuan， ji ti. Certainly it does not mean that there is no situation of one for two， but very few.
To sum up， in order to taste refined literature works and appreciate different poems， understand the greatest delight of the diction， enjoy aesthetic perception， mole the sentiment， and guarantee the accuracy of the accuracy of the poetry translation practice and examination， it is very necessary for us to pay attention to contrastive study on Chinese and English onomatopoeia.
References：
第3篇：米尔恩范文
To enhance plugging performance of microgels， a series of microgels with varied cationic degrees was synthesized by inverse microemulsion polymerization with acrylamide and methylacryloxylethyl trimethyl ammonium chloride as monomers. The properties and performance of cationic microgels were examined by transmission electron microscope， dynamic light scattering analysis， viscosity measurement and plugging test. The results show that cationic microgel exhibits better ability in water adsorption and viscosity enhancement than nonionic microgels. It can efficiently plug formation with permeability lower than 1200×10-3 μm2 （mD）， compared to 800 mD of nonionic microgels. The optimal cationic degree is 10%.
Key words： Cationic microgel； Polyacrylamide； Profile control
INTRODUCTION
With water-flooding reserviors matured， serious vertical and lateral heterogeneity gives rise to channeling of injection water along high permeable streaks. This results into water bypass and poor swept volume. Thus facile profile modification treatment is badly needed now than ever before.
Recently considerable attention has been paid to gel technology with varied formulations for different reservoir condition， usually including bulk injection[1]， double fluid cross-linked gel[2]， colloidal dispersion gel[3]， and pre-performed gel[4]. From these applications and the feedback of field practice， it comes out the state of art of these techniques described as follows. （1） Bulk injection has robust gel chemistry and is highly insensitive to petroleum reservoir environments and interferences， however， great efforts should be devoted to ensure indepth placement. （2） With double fluid crosslinked gel， crosslinkers like chromium acetate are apt to be adsorbed， dispersed or diluted in advance front. Consequently these adverse behaviors render that the strength of formed gel is questionable. （3） Colloidal dispersion gel treatments are economic and effective due to low polymer concentration and comparable size of polymer coil with pore scale， but its application is restricted by salt effect and fragile temperature resistence. （4） Pre-performed gel， to some extent， wins out from these four gel technique for getting rid of the other three’s shortcoming listed above. However， its complex production process including drying， grounding and meshing， multiply the cost of its applicable promotion； furthermore， the mixing of drying gel particle and injection water needs elaborated control of particle swellability.
In the 1997， the industry consortium （BP， Chevron Texaco and Nalco company） developed a novel， time delayed， and highly expanded particle system， named“Bright Water”[5]. This system composed of microgels with diameter around 0.1-3 μm synthesized by emulsion polymerization. It has been practiced for more than 85 treatments since the first application in Minas Field， Indonesia. Several successful cases have been reported in these years[6]. According to the profile-control mechanism raised by Chauveteau et al.[7]， microgels act by its swellability， viscosification and retention. Introducing cationic group in microgel can improve swellability by electrostatic repulsion between polymer chains and thus increasing viscosity of microgel solution. However， cationic microgels are seldom reported in profile control.
Based on above analysis， a series of microgels with cationic degree 0-50% （defined by the molar percentage of cationic monomer in total monomer） was synthesized by inverse microemulsion polymerization. The microgel properties including swellability and viscosity were determined. The corresponding performance in plugging test was compared with nonionic polyacrylamide microgels.
1. EXPERIMENTAL
1.1 Materials
Acrylamide （AM） and 78wt% water solution of methylacryloxylethyl trimethyl ammonium chloride（DMC） were used as monomers. Methylene bisacrylamide（MBA） as crosslinker， ammonium persulfate （APS） and sodium sulfite （SDS） as redox initiator， Span80（Sorbitan monooleate， chemically pure） and Tween60（Polyoxyethylene （20） sorbitan monostearate， chemically pure） as emulsifier were used without purification. Industrial white oil was chosen as the continuous phase.
1.2 Microgel Synthesis by Inverse Microemulsion Polymerization
The surfactant and oil with predetermined amount were mixed in a three-neck round-bottom flask equipped with stirrer， thermometer and nitrogen inlet. The reactor was placed in the 30 ℃ water bath. Then the water phase composed of DMC， AM and MBA was added. This mixture was stirred at 300rpm for 10 min to prepare microemulsion. Following 15 min nitrogen purge， the mixture was initiated with 0.01g APS/SDS. After reacting for 1h， a translucent emulsion was obtained for the below use.
1 . 3 M i c r o g e l M o r p h o l o g y a n d S i z e Characterization
Microgel morphology was observed by transmission electron microscopy （TEM， JEM-2100UHR）. Particle size and distribution were measured at 30℃ by dynamic light scattering method using Mastersizer 3000 high-speed intelligent particle size analyzer. For each sample， three tests were performed.
1.4 Viscosity Measurement
The viscosity of microgel solution was measured by Brookfield Viscometer LVDVII plus pro with ULA and SC4 spindles at 20 ℃.
1.5 Plugging Test
Sand packs were prepared by wet method described by Ding et al.[8] with 120-140 mesh quartz sand in the middle part and 80-100 mesh at both ends to prevent fine sand from leaking. After packing， three procedures were performed， as listed below： （1） inject water to get the initial pressure P0； （2） inject 0.5wt% microgel solution with slug size 0.5 pore volume （PV） and record maximum pressure P1； （3） inject water continuously and record balance pressure P2. The resistance factor （Fr） and the residual resistance factor （Frr） are calculated by P1/P0 and P2/P0， respectively. The injection rate is constantly 0.5mL/min.
2. RESULTS AND DISCUSSION
2.1 Microgel Morphology and Size
The morphology of 10%DMC original microgel in inverse emulsion is shown in Figure 1， where the particles are spherical and relatively uniform. The TEM photo of swollen microgels is shown in Figure 2. It can be seen from Figure 2 that the swollen microgels are a kind of particles with a tightly holden core and lightly crosslinked shell.
2.2 Viscosity
Here， relative zero shear viscosity （ηr0） is used to represent viscosity of microgel solution. To obtain ηr0， curves of solution viscosity versus mass concentrations （0.1%-1%） were determined for four type microgels. These microgels are seperately 0%， 5%， 10%， 50% cationic degree. These viscosity-shear rate curves are fitted to the Cross model[11]， which is known to provide a good description of the viscosity of colloidal suspension. The calculated ηr0 versus mass concentration （c） is shown in Figure 4. In Figure 4， ηr0 increases with the increasing cationic degree of microgels at the same concentration. The ηr0 of 0% DMC ranges from 1 to 5， while for 50% DMC it ranges from 15 to 290. The viscosity of cationic microgel is ten times that of nonionic microgels at the same concentration. And with c increasing， ηr0 sharply increases for 50% DMC while only moderately increases for 0% DMC. The increasing viscosity for higher cationic degree is attributed to electroviscous effect[12].
If plugging rate of 50% （Frr=2） is taken as the criterion for selecting microgels， the nonionic microgels are limited for use at formation permeability lower than 800 mD. The cationic microgels extend this limitation to 1200 mD. And 10% DMC microgel is the best fit for use because of its lower cost than 50% DMC microgel.
CONCLUSION
Microgels with different cationic degrees are synthesized by inverse microemulsion polymerization with AM and DMC as monomers. These microgels have a size range 50-100 nm in inverse emulsion and expand to 700 nm to 1700 nm after swollen by water. The maximum swellability is achieved at 10% DMC. The viscosity of cationic microgels is about ten times of nonionic microgels at the same concentration. In plugging test， the cationic microgels extend the permeability limitation for effective use to 1200 mD from 800 mD of nonionic microgels. 10% DMC microgel is the best fit for use because of its low cost.
REFERENCES
[1] Dai， C. L.， You， Q.， Xie， Y. H.， He， L.， Cui， Y.， & Zhao， F. L.（2011）. Case Study on Polymer Gel to Control Water Coning for Horizontal Well in Offshore Oilfield. Offshore Technology Conference， 2-5 May 2011， Houston， Texas， USA.
[2] Nanda， S.， Kumar， R.， Sindhwani， K.， & Goyal， K. （1987）. Characterization of Polyacrylamine-Cr+ 6 Gels Used for Reducing Water/Oil Ratio. SPE International Symposium on Oilfield Chemistry， 1987， San Antonio， Texas.
[3] Chang H.， Sui， X. G.， Xiao， L.， et al. （2004）. Successful Field Pilot of in-Depth Colloidal Dispersion Gel （Cdg） Technology in Daqing Oil Field. SPE/DOE Symposium on Improved Oil Recovery， 2004， Tulsa， Oklahoma， USA.
[4] Coste， J.-P.， Liu， Y.， Bai， B.， Li， Y.， Shen， P.， Wang， Z.， & Zhu， G. （2000）. In-Depth Fluid Diversion by Pre-Gelled Particles. Laboratory Study and Pilot Testing. SPE/DOE Improved Oil Recovery Symposium， 3-5 April 2000， Tulsa， Oklahoma.
[5] Frampton， H.， Morgan， J.， Cheung， S.， Munson， L.， Chang， K.， & Williams， D. （2004）. Development of a Novel Waterflood Conformance Control System. SPE/ DOE Symposium on Improved Oil Recovery Tulsa， 2004， Oklahoma， USA，.
[6] Garmeh， G.， Izadi， M.， Salehi， M.， Romero， J.， Thomas， C.， & Manrique， E. （2012）.Thermally Active Polymer to Improve Sweep Efficiency of Waterfloods： Simulation and Pilot Design Approaches. SPE Reservoir Evaluation & Engineering， 15（1）， 86-97.
[7] Chauveteau， G.， Tabary， R.， Blin， N.， et al. （2004）. Disproportionate Permeability Reduction by Soft Preformed Microgels. SPE/DOE Symposium on Improved Oil Recovery， 17-21 April 2004， Tulsa， Oklahoma.
[8] Ding， B.， Zhang， G.， Ge， J.， & Liu， X. （2010）. Research on Mechanisms of Alkaline Flooding for Heavy Oil. Energy & Fuels， 24（12）， 6346-6352.
[9] Hoare， T.， & Pelton， R. （2007）. Functionalized Microgel Swelling： Comparing Theory and Experiment. The Journal of Physical Chemistry B， 111（41）， 11895-11906.
[10] Kiatkamjornwong， S.， & Phunchareon， P. （1999）.Influence of Reaction Parameters on Water Absorption of Neutralized Poly （Acrylic Acid-Co-Acrylamide） Synthesized by Inverse Suspension Polymerization. Journal Of Applied Polymer Science， 72（10）， 1349-1366.
第4篇：米尔恩范文
*Corresponding author.
Supported by Korea Gas Corporation.
Received 12 January 2012; accepted 15 February 2012
Abstract
There is increasing interest in micellar-polymer flooding because of the need to increase oil production from depleted and waterflooded reservoirs. Using horizontal wells for injection and production in a micellar-polymer flood process, higher sweep efficiency is expected compared with the use of conventional patterns by vertical wells. However, the use of horizontal wells is very sensitive to the well pattern designed to operate the process. This paper presents an analysis of how the overall performance of a micellar-polymer flood process in anisotropic reservoirs is influenced by the well pattern using horizontal injector and producer in different configurations.
A three-dimensional numerical simulator for fluid flow and mass transport is used to analyze the effectiveness of well combinations in micellar-polymer applications. The potential for a horizontal well application was assessed through different situations in combinations of injection and production wells and degree of reservoir anisotropy. Results from the study have demonstrated that significant amount of oil can be recovered additionally and injectivity was remarkably improved by utilizing a combination of horizontal wells. The improvement of injectivity through a horizontal injection well was higher when it was combined with horizontal producer parallel to the injector. The overall performances in anisotropic reservoirs strongly depend on the type of wells considered and the orientation of the horizontal wells with respect to the permeability directions. Combination of horizontal wells placed parallel to the low permeability direction yields the best performance. In high permeability ratio reservoirs, the presence of horizontal injectors is more significant in defining the efficiency of the micellar-polymer flood than the horizontal producers.
Key words: Micellar-polymer flood; Horizontal well; Anisotropy; Injectivity
INTRODUCTION
Micellar-polymer flooding is an enhanced oil recovery(EOR) mechanism that can be often utilized after the natural drive or waterflood mechanisms become ineffective. During micellar-polymer flooding projects, water with surfactant is injected to achieve ultra low interfacial tension (IFT) which causes to decrease the residual oil saturation trapped by capillary forces. Lowering the mobility ratio, polymeric additives are used to improve a sweep mechanism that drives the reservoir oil toward the production wells[1, 2].
The efficiency of this EOR process is dependent on a number of parameters that are specific to the field under study. Most of the micellar-polymer flooding projects use vertical wells as injectors and producers, however, horizontal wells promise greater injectivity and productivity characteristics. The higher injectivities allows surfactant-polymer slug and polymer solution to be injected at much higher rates or lower pressures in horizontal wells than in vertical wells, which leads to allowing oil to be recovered quicker or with less energy. The use of horizontal wells has been increasing very rapidly throughout the oil industry as advances in drilling techniques continue. Horizontal wells have been used primarily in problem reservoirs or to solve specific production problems including low permeability fractured formations, low-permeability gas reservoirs, unconventional gas sources such as coal-bed methane or shale, gas or water coning, and thin formations. Because the horizontal well technology is recently being applied to the production of crude oil by waterflooding or enhanced oil recovery methods, little information is available on the horizontal-well applications for chemical floods[3-5].
Although there is relatively little published information on the use of horizontal injection or production wells other than for thermal recovery[6], the need for patterns of both horizontal injection and/or production wells to increase the rate of flooding in EOR processes has been increased. In this study, a comparison of the efficiencies of both horizontal and vertical wells in micellar-polymer flooding operations is performed. The influences of reservoir anisotropy coupled with various design parameters of well patterns are also studied. The study of these effects may assist the project design engineers in choosing the most optimal operating conditions that will maximize the efficiency of the process. With the goal of identifying these conditions, the effectiveness of the horizontal and vertical wells in micellar-polymer flooding projects is examined by simulating the process numerically.
1. MATHEMATICAL THEORY
Simulation of micellar-polymer flood processes includes modeling phase behavior, oil-water IFT and as a function of surfactant concentration, surfactant and polymer concentration-dependent viscosities, salinity and permeability dependence of adsorption, shear-thinning rheology of the fluids, and permeability reduction[7]. The numerical study was performed with the UTCHEM software, which is a general reservoir simulator. Among the most advanced chemical EOR simulators, UTCHEM has proved to be particularly useful for modeling multicomponent and multiphase transport processes[8]. UTCHEM has been extensively verified by comparing to analytical solutions and experimental measurements for its ability to predict the flow of fluids through the reservoir. Thus, UTCHEM will be used in this study for simulating multi-dimensional micellar-polymer flood processes for enhanced recovery of remaining oil in the reservoir.
where κ is component index including water (κ=1), oil (κ=2), surfactant (κ=3), and polymer (κ=4); l is phase index including aquatic (l=1), oleic (l=2), and microemulsion (l=3) phases; φ is porosity;Clu is overall
concentration of component κ (volume fraction);ρk is
density of component κ [ML?3]; np is number of phases; Cκl is concentration of component κ in phase l (volume fraction); ul is Darcy velocity of phase l [LT?1]; Sl is saturation of phase l; Rκ is total source/sink term for component κ (volume of component κ per unit volume of porous media per unit time); Dκl is dispersion tensor. The overall concentration (Clu ) denotes the volume of
component κ summed over all phases.
2. NUMERICAL MODELING
In this study, investigations on the effects of reservoir anisotropy on both horizontal and vertical wells performances in micellar-polymer flooding operations have been conducted. Numerical simulation runs were conducted in a three-dimensional oil reservoir that includes the reservoir thickness, i.e., gravity and capillary forces are simultaneously considered. To simulate the performance of the micellar-polymer flood processes, a hypothetical study site of one-quarter of an injectionwell-centered five-spot is considered. The modeled system used in this study is a box-shaped reservoir with a horizontal area of 253×253 ft2 and a vertical thickness of 25. Vertically, the simulation domain consists of five layers; and each layer is discretized into 23×23 grid blocks. The outer boundary is represented as a noflow. The reservoir investigated in this study was assumed to have already been waterflooded and is a potential candidate for micellar-polymer flood. The model assumes that the reservoir is originally saturated with oil and connate water. Initial saturation of water was assumed to be uniform spatially in the reservoir at 0.50. The uniform permeability of 250 md is assumed for both horizontal and vertical directions.
Micellar-polymer flooding process considered in this study involves the injection of a surfactant-polymer slug followed by a polymer drive and chase water injection. Fluids are pumped into the injection well at constant pressure of 650 psi over a simulation period of 1,000 days. The reservoir fluids are recovered from the production well operating at a sand face pressure of 500 psia, the same pressure as the initial reservoir pressure.
In order to clarify the effects of various parameters during the flow through the reservoir, comparisons were made among results from simulations under different sce-narios of micellar-polymer flood. Different combination of injection-production well pattern and reservoir anisotropy were considered for this study. Reservoir oil, formation water, petrophysical properties of the reservoir, and injec- tion/production procedure were identical for all calculations. Input parameters for the simulations are those that define the physical properties of reservoir, fluid properties, and chemical properties, as given in Table 1.
3. RESULTS AND DISCUSSION
The model evaluated the flow of brine associated with surfactant and/or polymer and oil through a reservoir during the process. To understand the effects of various parameters on the oil recovery, simulation was performed with the injection sequence of micellar-polymer flooding followed by waterflooding. Volumetric fraction of surfactant in the injecting fluid is 0.03 during 0 to 180 days. Polymer concentration is 0.05% during 0 to 180 days, 0.025% during 180 to 360 days, and 0 % for remaining period in the chase water.
Several cases were studied in which the sensitivity of oil recovery and injection rate to the well configuration(well type and length) was determined. Performance of micellar-polymer flooding with vertical wells was determined by comparing the oil recovery and injection rate from a base case with the oil recovered from the various micellar-polymer floods over production period. 3.1 Well Types
Extensive simulations were undertaken to investigate the feasibility and compare applicability of micellar-polymer flood through vertical and horizontal wells. The objective of this parametric study is to investigate the effect of horizontal well orientation on the overall performance of micellar-polymer flooding projects using different injector/ producer combinations. The ratio of horizontal well length to reservoir length was 0.52, which corresponds to well length of 132 ft. During this part of the investigation, the following nine injection and production well combinations are considered:
(1)First combination (VzIVzP): vertical injector and vertical producer (base case)
(2)second combination (VzIHxP): vertical injector and horizontal producer along the x-direction
(3)third combination (VzIHyP): vertical injector and horizontal producer along the y-direction
(4)forth combination (HxIVzP): horizontal injector along the x-direction and vertical producer
(5)fifth combination (HxIHxP): horizontal injector along the x-direction and horizontal producer along the x-direction
(6)sixth combination (HxIHyP): horizontal injector along the x-direction and horizontal producer along the y-direction
(7)seventh combination (HyIVzP): horizontal injector along the y-direction and vertical producer
(8)fifth combination (HyIHxP): horizontal injector along the y-direction and horizontal producer along the x-direction
(9)sixth combination (HyIHyP): horizontal injector along the y-direction and horizontal producer along the y-direction
Figure 1 presents a schematic representation of these combinations.
Results of the calculations for isotropic reservoirs are shown and compared in Figure 2 for various combinations of vertical and horizontal floods. As presented in the figure, the oil recovery and injection rate are highly influenced by the well patterns. It can be seen that the predicted values from the reservoir simulation illustrate higher oil production and lower water production from horizontal micellar-polymer flooding.
The fifth and ninth combinations yield the highest additional production to the base case. This is expected since these combinations adopted only horizontal wells for injection and production and the producer and the injector have the same orientation. With horizontal wells aligned to the same orientation, areal sweep patterns are a lot closer to line-drive geometry the production will be maximized during the early injection period. The other combinations including horizontal wells also show markedly better performances than the base case as presented in Figure 2. The improvement of oil recovery can be attributed to the higher injection rate and larger area open to flow and resulting improved sweep efficiency in horizontal wells than that of vertical wells.
Figure 2(b) compares the results of injection rate for different injector-producer combinations, against the performance of the first combination which is considered as the base case. This comparison indicate that horizontal well floods result in the much higher rate compared to an equivalent five-spot flood at the same pressure. At early time, the presence of horizontal injectors seems to be more beneficial than the presence of horizontal producers. Conversely, the presence of horizontal producers is more beneficial than the presence of horizontal injectors after water breakthrough.
The combination of horizontal injector and producer shows the highest injection rate. The injection rate in HyIHyP at the same operating pressure would be about 6.1 times higher than that for the base case, which represents a significant improvement in injectivity and high effectiveness to sweep the reservoir oil over values attained by the model of vertical wells. The result implies that the same volume of fluid can be injected at much lower pressure, in turn. The higher injectivities allowed by horizontal injection wells can help to alleviate substantially less injectivity of a vertical injection well. The higher injectivity associated with horizontal wells can also help to mitigate the effects of chemical and thermal degradation of injecting fluids.
Figure 3 depicts oil saturation of the middle layer for five different well patterns including VzIVzP, VzIHxP, HxIVzP, HxIHyP, and HxIHxP after 410 days of injection. The sweep efficiency advantage of horizontal well flooding patterns would be observed best for horizontal injector and horizontal producer aligned to the same orientation. Analyzing the results presented in Figure 3, the swept region did not cover the entire area of the layer with vertical injector or producer. In cases of horizontal injector and producer, the flood front covered almost the entire region. The pore volumes injected for the well patterns are 0.43, 0.79, 0.49, 1.36, and 1.08 for VzIVzP, VzIHxP, HxIVzP, HxIHyP, and HxIHxP, and cumulative oil recoveries are 0.32, 0.51, 0.33, 0.59, and 0.60, respectively. The highest sweep efficiency was obtained for a pattern HxIHxP in which injected fluid and the produced fluid are flowing by two parallel horizontal wells. This type of well pattern is called inverted line drive pattern and has the advantage of using the entire length of the horizontal section for sweep. As compared to the sweep patterns that developed between vertical wells, areal sweep patterns are closer to line-drive geometry in horizontal wells.
3.2 Reservoir Anisotropy
This parametric study is to examine the performances of horizontal and vertical well combinations in micellarpolymer flooding a reservoir that exhibits anisotropic permeability characteristics. In the runs considered, the ratio of permeability of the reservoir along the x-direction to the permeability of the reservoir along the y-direction is assigned to be 0.25, 0.5, 1.0, 2.0, and 4.0, keeping the geometric mean constant. Nine different well combinations are also considered during this parametric study.
Figure 4 shows the change in cumulative oil recovery when the first combination is replaced by the second through the ninth combinations summarized above. When the horizontal wells are placed parallel to the low permeability direction or orthogonal to the high permeability direction, the horizontal combination yields the best performance. The overall performance of the combinations considered in this parametric study strongly depends on the type of wells considered and the orientation of the horizontal wells with respect to the permeability directions.
For permeability ratio less than 1.0 or higher permeability to the y-direction, combinations with horizontal well along with x-direction performs better. Due to the rapid and better sweep efficiency, the cumulative oil recovery of HxI and/or HxP remained remarkably higher. The results in Figure 4(a) indicate that HxIHyP, HyIHxP, and HxIHxP provide increment of 44%, 54%, and 73% more oil than VzIVzP does. Comparing the performances of HxIHyP and HyIHxP, the reservoir performance is more strongly influenced by injection well up to 230 days, then by production well. Comparing Figure 2 and Figs. 4 (a) and (b), one can observe a higher oil recovery and a less difference in oil recovery among cases for smaller ratio of permeability.
Results in Figs. 4(a) and (b) also show that the advantages of combinations of horizontal injection and production wells for micellar-polymer flooding are greatest for patterns aligning orthogonal to high permeability direction. Therefore, equivalent (or better) water injection and oil production rates can be achieved in anisotropic reservoirs with far fewer horizontal wells along proper direction than with vertical wells. The smaller the permeability ratio, the larger difference in oil recovery was observed. For example, differences in oil recovery between VzIVzP and HxIHxP for kx/ky = 1.0, 0.5, and 0.25 are 57%, 64%, and 73%, respectively. Although individual horizontal wells cost much more, the total drilling costs could be less than for vertical-well patterns because fewer wells are drilled at the wider spacing.
CONCLUSIONS
Based on the studies carried out in this work in order to evaluate the oil recovery efficiency of a micellar-polymer flooding process with various combinations of horizontal and vertical wells, the following conclusions are drawn. Because of the improved injectivity and the potential for increased recovery by better sweep efficiency, the use of horizontal wells during micellar-polymer flooding could offer remarkably significant benefits as compared to the results obtained in a conventional pattern processed by vertical wells. Regardless whether the formation exhibits isotropic or anisotropic permeability characteristics, it is essential to place the horizontal producers and injectors parallel to each other to obtain better performance efficiency than the vertical well combination. A very favorable injectivity and sweep occur when two opposed horizontal wells parallel in the pattern are used for injection and production. Compared to five spot patterns with vertical wells, the combination of parallel horizontal wells can increase oil recovery by 40% and injectivity by as much as a factor of two.
In anisotropic reservoirs, the oil recovery will be maximized when the horizontal producers and injectors are orthogonally placed to the high permeability direction. In high permeability ratio reservoirs, the presence of horizontal injectors parallel to the low permeability direction becomes more dominant in defining the efficiency of the micellar-polymer flood than the horizontal producers.
REFERENCES
[1] Thomas, S., & Farouq Ali S. M. (2001). Micellar Flooding and ASP-Chemical Methods for Enhanced Oil Recovery, J. Canadian Petrol. Tech., 40(2), 46-52.
[2] Hirasaki, G. J., Miller, C. A., & Puerto, M. (2008). Recent Advances in Surfactant EOR, IPTC 115386, SPE Annual Technical Conference and Exhibition. September 21-24, Denver, CO.
[3] Taber, J. J., & Seright, R.S. (1992). Horizontal Injection and Production Wells for EOR or Waterflooding. SPE 23952 SPE Permian Basin Oil and Gas Conference. March 18-20, Midland, TX.
[4] Dakhlia, H., Wu, W., Lim, M. T., Delshad, M., Pope, G. A.,& Sepehrnoori, K. (1995). Simulation of Surfactant Flooding Using Horizontal Wells. CIM 95-82, Petroleum Society of CIM 46th Annual Technical Meeting. June 7-9, Banff, Alberta, Canada.
[5] Westermark, R. V., Schmeling, J., Dauben, D. L., Robinowitz, S., & Weyland, H. V. (2006). Application of Horizontal Waterflooding to Improve Oil Recovery from Old Oil Fields. SPE 99668 SPE/DOE Symposium on Improved Oil Recovery. April 22-26 Tulsa, OK.
[6] Shedid, S. A. & Abbas, A. A. (2000). Comparison of Chemical Steam Floods Through Vertical and Horizontal Wells. CIM 65482 SPE/Petroleum Society of CIM International Conference on Horizontal Well Technology. November 6-8, Calgary, Alberta, Canada.
[7] Fadili, A., Kristensen, M.R., & Moreno, J. (2009). Smart Integrated Chemical EOR Simulation. IPTC 13762 International Petroleum Technology Conference. December 7-9, Doha, Qatar.
第5篇：米尔恩范文
“嗨，哥哥也在这啊”夕雅正在不二家的花园里欣赏着，正碰巧看到了做到草地上的不二“呵呵，夕雅也来了？”依旧微笑，佩服佩服
“哥哥，知道吗？我一直很想要一个跟哥哥一样的BF呢”这点她可没有说谎哦，至少她现在这么认为“是吗？”“恩，恩，唉？哥哥，嘿嘿……我想到了一个不错的恶作剧呢，不过需要哥哥稍稍的配合一下。嗯？好不好嘛”
-——————————————青学————————————————
“谢谢你哦，米尔”“不用客气，为主人带路是应该的”“呵呵”真是多亏了米尔，因为昨天的恶作剧行动，我就没有让不二哥哥送我去青学，可哪知，我根本是个路痴。幸好有米尔给我带路，要不我根本找不到青学，唉！~算了，先去我的新教室吧。说起来好像和龙马一班啊。“铃铃铃……”
“同学们好”
“老师好”
刚刚上课，但貌似老师忽略了一个人，他正在睡觉呢。不说也知道是谁吧，真是的，才早晨就睡着了
“同学们，今天咱们班要转来一个新同学。她叫观丘夕雅”（恶搞之一）等老班说完我走上讲台，在黑板上写下了自己的名字“我叫观丘夕雅，请多多指教”，等我鞠完一个45°的躬后，朝下一看，好多人议论我啊“我一定要把这个女孩追到手”“她好可爱哦”“哇塞，真漂亮耶”…。.
切，什么嘛？一个帅哥也没有，一群草痴，我要是被他们追到手，不就白姓不二了？哼！
“观丘同学，你就坐到龙马旁边吧”老班指着睡得很香的龙马，我轻轻走过去，怕吵醒了他。
——————————-男——子——网——球——部 ————————————
“喂，周助（恶搞之…二吧）我在这，来到男子网球部后（米尔带的路）我一眼就看到了不二“嗨，夕雅”
“我靠，她是谁啊？竟然叫不二学长周助？”
“三八”
“切，不二怎么会看上她啊？”
我没理会那些女花痴愤怒的目光，跑过去抱住了不二的脖子“照计划行事”我在下来的那一瞬间说“你终于来了”
“嘻嘻，”
“不二竟然抱那个女生”
“那女的还想活吧，不怕惹上露琴？”
第6篇：米尔恩范文
【Key words】PPP； TBL； teaching methods
1.Introduction
These days， many different teaching methodologies are applied in English Language Teaching.Teachers have a great numbers of ideas to use in the classroom.However， the time of a class is limited and precious， so teachers should compare and analyze the methodology that they use in the classroom.This essay first focuses on comparing and contrasting two teaching methods， which are PPP and TBL.PPP， according to Thomas （2013）， involves language being presented by the teacher a it in order to accomplish the task that has been set before them. （Larsen-Freeman & Anderson， 2011， p.150）.Then the essay will discuss how PPP and TBL impact upon tnd practiced and produced by the student.In contrast， Task-based Learning （TBL） is a methodology in which students acquire the language that need when they needeachers and learners.It will also look at the strengths and weakness of these two methodologies.
2.The similarities and differences between PPP and TBL
PPP and TBL， as two common teaching methodologies， share some similarities.Firstly， both PPP and TBL teaching methods can activate learners’ language knowledge.Specifically， at the last stage of presentation-practice-production method， “here the students are asked to use the new language in sentences of their own.” （Harmer， 2007， p.65）.Similarly， the teacher will set a task in TBL teaching， “the aim of the task was to encourage students to activate a range of language functions and structures...” （Nunan， 2004， p.21）.Thus， learners’ language knowledge can be activated by using language.Secondly， the context is given in the process of PPP teaching， as well as TBL teaching.In PPP procedure， “the teacher introduces a situation which contextualises the language to be taught.”（Harmer， 2007， p.64）.It means that at the beginning of the PPP teaching， the language is placed in clear situational contexts.This happens in the TBL procedure.Willis （1996） suggests that TBL includes three basic stages：the Pre-task， the Task cycle and the Language focus.It can be seen that the task runs through the TBL teaching process， and the learner has to think about the task in the specific context， so both PPP and TBL give the clear context to learners.
PPP， on the other hand， differs from TBL in significant aspects.According to Harmer （2007）， PPP is teacher-centered and fits uneasily with more humanistic and learner-centered framework.Clearly， the teacher controls the class and the learner is dependent on the teacher to new languages.Conversely， according to Brandon （2013）， TBL is a learner-centered methodology.Learners learn to discover features in language， and they can use language they learn from other lessons and sources.Another difference is that PPP focuses on accuracy while the focus of TBL approach is fluency.Harmer （2007） points out that the teacher corrects any mistakes he or she hears from the learner during PPP procedure.In contrast， in a lesson which use TBL method， “the focus of the lesson is the task， not the structure.”（Harmer， 2007， p.71）.Only when the task has clear outcomes will the teacher discuss the language that the learner uses.Plus， TBL method is more flexible than PPP method， so that the language expose in TBL is rich and varied.“The language comes out of what learners know/ can do / want to do， and out of the task.” （Willis， 1996， p.61）.PPP， conversely， is more controlled and only allows learners to use the language given by the teacher.The language expose， therefore， is limited.
3.The influence on teachers and learners
Turning to the issue that how PPP impacts teachers and learners， preparing a lesson with PPP method is easy for teachers， because the materials used for the lesson are ordered from simple to difficult.The framework of PPP is simple and allows teachers to control the pace of the lesson.It seems that PPP has no negative effect on teachers.As observed at the high school in China （2013）， learners may feel comfortable as they are producing the new language accurately in the class.But after a few lessons， learners will often not be able to produce the language correctly or even will not produce it at all.Besides that， it shows that there are other merits and demerits in PPP procedure.Harmer （2007） considers that PPP is extremely effective in a focus-on-form lesson， especially at lower levels.But he adds that PPP becomes less useful when the learner has already known a lot of language， and therefore may not meet the needs of the learner.Further more， PPP does not motivate learners， because it does not give opportunities to learners to work out the language form by themselves.
The TBL， however， impacts teachers and learners in different ways.It is not easy for teachers to choose a task that is appropriate to the level of learners and based on learners’ needs.In a word， TBL teachers face complex challenges.The greatest influence on learners is that their interests in learning a language is stimulated.They can control the communication and discover the language by themselves.That is also one of the advantages of TBL.“The goal of the task provide the main motivation； students generally want to achieve the task outcomes which involves them in playing games or solving a problem.” （Willis， 1996， p.60）.Larsen-Freeman & Anderson （2011） also demonstrate that students are motivated by doing tasks that related to the real world.Moreover， the skills required in TBL are integrated.Task refers to “activities involving any of the four language skills.” （Ellis， 2003， p.7）.In the process of completing the task， the four language skills， included listening， speaking， reading and writing skills， can be improved.However， Ellis （2003） attempts to analyze how complex is TBL for teachers and learners.It seems likely that the lesson structure is not suitable for low level learners and inexperienced teachers.
4.Conclusion
In conclusion， by comparing and contrasting， PPP and TBL share some similarities， but also the two methodologies differ from each other in significant aspects.In addition， both PPP and TBL have their strengths and weaknesses.PPP may be used more widely by English teachers， whereas it is challenging for teachers to manage the task-based class.Nevertheless， it turns out that TBL is more effective in encouraging learners to work together and acquire language through using it.Teachers can set up different task in TBL teaching in order to let learners improve the four skills， which are listening， reading， writing and speaking.Moreover， “task-based instruction can help to encourage students to use the target language actively and meaningfully.” （Larsen-Freeman & Anderson， 2011， p.160）.Since motivation is one of the vital aspects of education， TBL should be considered an effective method for language teaching and it should be increasingly used in schools.
Reference：
[1]Ellis，R.（2003）.Task-based Language Learning and Teaching.Oxford： Oxford University Press.
[2]Harmer，J.（2007）.The practice of English language teaching.Harlow： Longman.
[3]Larsen-Freeman，D.& Anderson，M.（2011）.Techniques & Principles in Language Teaching.Oxford： Oxford University Press.
第7篇：米尔恩范文
On July 6, 2005, prior to the 58th DPI/NGO Annual Conference, the China NGO for International Exchanges, a newly established coalition composed of all the Chinese NGOs having acquired consultative status with UN ECOSOC and other national Chinese NGOs, held a Chinese NGOs Forum for the 58th DPI/NGO Annual Conference in Beijing. Mr. Ramu Damodaran, Chief of the Civil Society Service in the Outreach Division of the UN/DPI and Sr. Joan Kirby, Chair of the Executive Committee of the 58th DPI/NGO Annual Conference together with more than 70 representatives from over 20 Chinese NGOs participated in this Forum. Officials from the Foreign Affairs Ministry and Civil Affairs Ministry attended the Forum and gave supportive address to the meeting. Revolving around the theme of “Our Challenges: Voices for Peace, Partnerships and Renewal” and closely linking their own practical work, the participants elaborated their views, put forward recommendations and voiced initiatives on how to give full play to their advantages and mobilize resources to accomplish the MDGs in China and throughout the world by 2015. Sr. Joan Kirby and Mr. Ramu Damodaran delivered informative and encouraging speeches extending warm welcome for the Chinese NGOs to participate more in the UN DPI/NGO activities in their own way.
The introduction of MDGs offered a framework for international cooperation for common development and is of vital importance for the realization of a safer and more peaceful world. The international community, especially the developed countries should concretely implement their aid obligations, fulfill their international commitment of gradually increasing the ODA up to 0.7% of their GDP respectively and work hard to eliminate regional disparities. The developing countries should stipulate national development strategies suitable to their own national conditions and realize the development objectives by making the best use of their own resources. The United Nations should intensify cooperation and partnership with the civil society. The NGOs from all over the world should shoulder their historical responsibility to monitor, assist and urge their governments to work harder to fulfill the MDGs. The participants reached the following consensus on poverty relief, environmental protection, medical care and health, science and technology, peace and security, employment and some other issues:
1. Governments, especially those from the developed countries, shall encourage and fund more NGOs to take part in poverty relief actions, turning from material aids only to capacity building so that the impoverished people could pull themselves out of poverty by their own efforts.
2. Governments shall spare no efforts in propelling the strategy of sustainable development. The NGOs shall help and monitor the governments so as to abridge the governments and the general public in achieving the MDGs.
3. Establishing a trans-national and trans-regional MDG Project Management Information System (MDGPMIS) supported by each participating country with the UN as its core, an MDG Project Decision Support System (MDGPDSS), an MDG Project Distance Training System (MDGPDTS), and an MDG Project Resource Monitoring System (MDGPRMS) to facilitate and speed up the implementation of MDGs. Setting up multi-institutional and cross-sector regional technical centres with the aid of the internet. Giving low-income countries the “MDG fast track” status and connecting these countries first with the information system and increasing development aid to them as well.
4. It is necessary to pay attention to and work for development of the family and the society in a coordinated way, to promote harmony and happiness in the family and to encourage the family to make contributions to the society. All social circles and sectors shall attach importance to strengthening dialogue and cooperation with the youth and their organizations, increase input to youth undertakings and care about the physical and psychological health of the younger generation.
5. It’s essential to reinforce vocational education and training as well as vocational guidance and job introduction so that service could be provided to the vulnerable groups of people in the society that earnestly need to find jobs and optimize their employment conditions. Employment of the surplus labour force in urban and rural areas and rational distribution of human resources could be solved.
6. Efforts shall be increased to strengthen the management over cultural heritages and resources, not only be developing, but also protecting them.
7. The international community needs cooperation instead of confrontation. Big powers shall shoulder their obligations to the international community in terms of peace, security and development.
8. Medical professional cooperation and training is essential for reducing maternal and neonatal mortality rate.
9. The Chinese NGOs are willing to make use of their unique advantages in each area and make tangible contributions to the accomplishment of the MDGs in China and throughout the world. We welcome the emerging opportunities for dialogue and partnership among the NGOs, member states and the UN system.
第8篇：米尔恩范文
*Corresponding author.
Received 17 October 2014; accepted 18 December 2014
Published online 26 January 2015
Abstract
Teachers’ corrective feedback has been the focus for some time in SLA. The study， based on the framework of teaching focus， corrective feedback and learner uptake by these researchers， explores how teachers’ corrective feedback is related to focus on instruction. The research method is a corpus-based approach， which relies on computer and corpus tool―Antconc 3.2.0w and Repetition Tool. The findings show that （a） MF Instru. invites the most CFSs， followed by F&M Instru. and FF Instru. respectively; （b）When teachers correct students’ errors， they pay much more attention to form-focused errors （FF errors） than to meaning-focused errors （MF errors）; grammatical errors attract the most attention whichever the instruction it is; in MF Instru. and F&M Instru.， though MF errors occupy a small proportion of all the errors， their number is larger than that of phonological errors and lexical errors; （c） In general， the majority of feedback type after FF errors （phonological， grammatical and lexical errors） is recast， whereas the majority of feedback type after MF errors is Negotia.C; as it is related to instruction types， in FF Instru.， teachers prefer to use Negotia.C to follow phonological and lexical errors， and recast to follow grammatical errors; in MF Instru.， teachers prefer to use recast to follow FF errors （phonological， grammatical and lexical errors）; in F&M Instru.， teachers prefer to use recast to follow phonological errors， Negotia.C to follow grammatical errors， and both Negotia.C and recast are preferred after lexical errors; （d） Negotia.C invites the most learner repair， followed by Expli.C and recast respectively; As it is related to instruction types， Negotia.C brings about the highest repair rate， and recast leads students to produce the lowest rate of repair in FF Instru.， MF Instru. and F& M Instru. as well.
Key words： Corrective Feedback Sequence （CFS）; Instruction focus; Error types; Feedback types; Uptake types
Xu， J. （2015）. A Study on Middle School English Teachers’ Corrective Feedback in Different Instructions. Canadian Social Science， 11（1）， <Page>-0. Available from： http：///index.php/css/article/view/6105
DOI： http：///10.3968/6105
INTRODUCTION
Feedback in L2 classroom lies at the core of research on teacher-student and student-teacher interaction in L2 classroom （Chaudron， 1988）.Corrective feedback and/or learner’s uptake have been hotly studied in the field of SLA classroom in foreign countries. For instance， Lyster （1998） explores the relationship among error types， feedback types and immediate learner repair （uptake） in four French immersion classrooms at the elementary level. It is necessary and meaningful to think about the question―how teacher s’ corrective feedback is related to teaching focus or focus of instruction. According to different teaching focuses， instruction can be divided into three types―form-focused instruction （FF Instru.）， meaning-focused instruction （MF Instru.） and both-form-and-meaning-focused instruction （F&M Instru.）.
Concerning of corrective feedback， a number of terms have been used， including “feedback”， “repair”， and “correction”. “Feedback” serves as a general cover term for the information provided by listeners on the reception and comprehension of the message. “Repair”is a somewhat narrower term used to refer to attempts to deal specially with linguistic errors; it constitutes an attempt to supply “negative evidence” in the form of feedback that draws the attention of the listeners to the errors they have made （Ellis， 1994， pp.583-584）. In this paper， corrective feedback is used as a general cover term to refer to various ways used by teachers to point out how close their attempt at English is to some form of Standard English.
Few empirical classroom researches have been carried out except for Tang （2005）， Shi （2005）， and Zhao （2005）. But all of the above three are carried out in limited English classrooms. Can these research findings apply to general English classrooms？ What is the general picture of teachers’ corrective feedback and its relationship with learner’s uptake in Chinese EFL middle school classrooms？ Will the focus of instruction （form-focused vs. meaning-focused vs. both-form-and-meaning- focused） have any influence on teacher’s corrective feedback？ In order to provide answers to the above questions， the author carries out a study on 155 lessons transcripts with the help of corpus tools.
1. RESEARCH QUESTIONS
As the general direction of the study is to investigate the relationship between teachers’ corrective feedback and the focus of instruction， the research question of the present study may go as follows： How is teachers’ corrective feedback related to focus of instruction？ According to different focuses， instruction is divided into three types： form-focused instruction （FF Instru.）， meaning-focused instruction （MF Instru.） and both-form-and-meaning-focused instruction （F&M Instru.）. The research question can be divided into the following four sub-questions：
（a） How often does corrective feedback occur in the three instructions？
（b） What type of error does corrective feedback aim at in each instruction？
（c） How is feedback type associated with error type in each instruction？
（d） How is feedback type associated with learner’s uptake type in each instruction？
The four sub-questions of the main research question are presented in form of figure as follows：
Figure 1
Framework of the Research Questions
In Figure 1， ① refers to the first sub-question， investigating the relationship between instruction types and corrective feedback in terms of frequency; ② refers to the second sub-question， investigating what type of error teachers correct in each instruction; ③symbolizes the third sub-question， focusing on what types of feedback is likely to go after what type of error in the three instructions respectively; ④ refers to the last sub-question， investigating the association between feedback types and uptakes types in each instruction.
2. RESEARCH METHOD AND TOOL
The corpus of this study contains 155 lessons. Among the 155 lessons， 88 are given by the junior middle school teachers in the years of 1997， 2004， 2006， 2007， 2008 and 2009; 67 are taught by the senior middle school teachers in the years of 1996， 2006， 2009， 2010 and 2011. The 155 lessons of classroom teaching have been included in the Corpora of English Education in China （CEEC）， which is built by the School of Foreign Studies of South China University， under the leadership of Professor He Anping. The 155 lessons in the present study are saved in the computer with the file name as EFLCT. It includes two sub-corpuses： JMSCT （junior middle school classroom teaching） and SMSCT （senior middle school classroom teaching）.
The present study mainly utilizes Antconc 3.2.0w and Repetition Tool as its research tool. The Repetition Tool was designed by the technician， Mr. Yang， in School of Foreign Studies in South China Normal University to extract the repetition segment. Under the title of File， such contents could be found： Choose File， Clear All， Clear Partially， Setting， Confirm and Cancel. Antconc 3.2.0w is a free corpus search tool， which contains seven main programs called Concordance， Concordance plot， File View， Clusters， Collocations， Word List and Keyword List. Concordance can be used to search any word or phrase in context. The distribution of the search word can be shown in Concordance plot in the form of chart. The whole text can be seen in File view. Cluster and Collocation can be used to display the words or phrases that go together with the search word. Wordlist can be used to make a list of words in alphabetical or frequency order. Keyword list can display the keyword of the text by comparing the text with another text. The present study requires the use of the function of concordance and file view.
The main methods are that first， based on the previous studies， establish the framework to analyze CFS; then， randomly choose 20 lessons to do a pilot study to conclude the search words and use corpus tool― Antconc 3.2.0w and Repetition Tool to pick out the CFSs. After picking out the CFSs， further analysis has been done for instruction types―form-focused instruction （FF Instru.）， meaning-focused instruction （MF Instru.） and both-form-and-meaning-focused instruction （F&M Instru.）， error types―phonological error， grammatical error， lexical error and meaning-focused error （MF error）， feedback types―explicit correction （Expli.C）， recast and negotiation of form （Negotia.C）， and uptake types―repair and needs-repair.
3. RESULTS AND DISCUSSION
The research data of corrective feedback sequence （CFS） will be analyzed both quantitatively and qualitatively from different angles so that the present study can objectively reflect the relationship between teachers’ corrective feedback and instruction types. The relationship between teachers’ corrective feedback and instruction types will be reflected in terms of the frequency of CFSs in each instruction， in terms of target of corrective feedback in each instruction， in terms of the relationship between feedback types and error types in each instruction， in terms of the association between feedback types and uptake types in each instruction. Therefore， students’ error types， teachers’ specific ways of feedback and learner’s uptake types respectively in form-focused instruction （FF Instru.）， meaning-focused instruction （MF Instru.） and both-form-and-meaning- focused instruction （F&M Instru.） are accordingly classified and analyzed in the following.
3.1 Frequency of CFS in Three Instruction Types
The present study identifies 596 teacher’s CFSs distributed in the three instructions： FF Instru.， MF Instru. and F&M Instru.. This section will concentrate on the relationship between corrective feedback and instructions in terms of the frequency of CFSs in the three instructions. Of the 596 CFSs， 72 are located in FF Instru.， 344 are spotted in MF Instru.， and the rest 180 lie in F&M Instru.. Table 1 shows the frequency of CFSs in FF Instru.， MF Instru. and F&M Instru..
Table 1
Frequency of CFSs in the Three Instructions
Occurring times Percentage （%）
FF instru. 72 12
MF instru. 344 58
F&M instru. 180 30
Total 596 100
Figure 2
Percentage of CFSs in the Three Instructions
Table 1 and Figure 2 indicate that 58% of the CFSs are found in MF Instru.， 30% are found in F&M Instru.， and 12% are found in FF Instru.. The Chi-square test of Table 2 indicates that the number of CFSs found in the three instructions is significantly different （x?=1.888×102， df=2， p=.000< .05）. The pairwise study of the frequency of the CFSs in the three instructions shows that the number of CFSs found in MF Instru. is significantly larger than that found in FF Instru. （x?=1.778×102， df=1， p=.000< .05）; the number of CFSs found in F&M Instru. is significantly larger than that found in FF Instru. （x?=46.286， df=1， p=.000< .05）; the number of CFSs found in MF Instru. is significantly larger than that found in F&M Instru. （x?=51.328， df=1， p=.000< .05）.
The analysis above reflects that MF Instru. invites the most CFSs， followed by F&M Instru. and FF Instru. respectively. FF Instru. invites the fewest CFSs.
3.2 Error Types of CFS in Three Instruction Types
This section focuses on the target of corrective feedback in FF Instru.， MF Instru. and BF Instru. respectively， that is， what type of error teachers tend to correct in each instruction. As has been mention in Chapter Three， the present study identifies two main types of errors： form-focused error （FF error） and meaning-focused error （MF error）. Table 2 shows the search result in the collected data.
Table 2
Distribution of Error Types
Error types Occurring times Percentage
FF error 488 82 %
MF error 108 18%
Total 596 100%
Table 2 indicates that the teachers usually notice more FF errors （82%） than MF errors （18%） when students’ output contains trouble source. The Chi-square test of Table 2 indicates that the number of FF errors is significantly larger than that of MF errors （x?=2.423×102， df=1， p=.000<.05）. Table 3 shows the search results related to the three instructions.
Table 3
Distribution of Error Types in Each Instruction
FF instru. MF instru. BF instru.
n % n % n %
FF error 72 100 270 78 146 81
MF error 0 0 74 22 34 19
Total 72 100 344 100 180 100
Table 3 indicates that when teachers in different instructions offer corrective feedback， they usually notice more FF errors than MF errors. In FF Instru.， all errors repaired by the teachers are FF errors. In MF Instru.， 78% of the errors corrected by teachers are FF errors and in F&M Instru.， 81% of the errors repaired by teachers are FF errors.
Since FF errors can be subdivided into three types： phonological error， grammatical error， lexical error， further study will be carried out to investigate the difference among phonological， grammatical， lexical and MF errors in each instruction. Tables 4-6 show the distribution of the four error types in FF Instru.， MF Instru. and BF Instru. respectively.
Table 4
Distribution of Error Types in FF Instru.
Occurring times Percentage （%）
Phonological error 29 40
Grammatical error 29 40
Lexical error 14 20
MF error 0 0
Total 72 100
Figure 3
Percentage of Error Types in FF Instru.
Table 4 and Figure 3 indicate that in FF Instru.， no MF errors are found， and of FF errors， grammatical errors occupy as large number as phonological errors， and larger number than lexical errors. A SPSS test is carried out to test the effect. The main effect of the error types in FF Instru. is significant （x?=26.889， df=1， p=.000< .05）. Pairwise analysis of the FF errors reveals that the teachers notice more phonological errors and grammatical errors than Lexical errors （x? =5.233， df=1， p=.022<.05）.
Table 5
Distribution of Error Types in MF Instru.
Occurring times Percentage （%）
Phonological error 40 12
Grammatical error 191 55
Lexical error 39 11
MF error 74 22
Total 344 100
Figure 4
Percentage of Error Types in MF Instru.
Table 5 and Figure 4 indicate that in MF Instru.， grammatical errors occupy a much larger number than phonological errors， lexical errors and MF errors， and MF errors are about twice as many as phonological errors and lexical errors. SPSS test result indicates that the main effect of error types is significant （x? =1.802×102， df=3， p=.000< .05）. Pairwise analysis of the four error types shows that the teachers notice more grammatical errors than phonological errors （x?=98.706， df=1， p=.000< .05）， lexical errors （x? =1.005×102， df=1， p=.000< .05）， and MF errors （x?=51.657， df=1， p=0.000< 0.05）， more MF errors than phonological errors （（x?=10.140， df=1， p=0.001< 0.05） and lexical errors （x?=10.841， df=1， p=.001< .05） ，while the teachers’ notice of phonological errors and lexical errors has no significant difference （x?=0.013， df=1， p=.910> .05）.
Table 6
Distribution of Error Types in F&M Instru.
Occurring times Percentage （%）
Phonological error 10 6
Grammatical error 116 64
Lexical error 20 11
MF error 34 19
Total 180 100
Figure 5
Percentage of Error Types in F&M Instru.
Table 6 and Figure 5 indicate that in F&M Instru.， grammatical errors occupy a much larger number than phonological errors， lexical errors and MF errors， MF errors are about three times as many as phonological errors， and lexical errors are about twice as many as phonological errors. SPSS test result indicates the main effect of the four types of error is significant （x?=1.558×102， df=3， p=.000< .05）. Pairwise analysis of the four error types shows that the teachers notice more grammatical errors than phonological errors （x?=89.175， df=1， p=.000< .05）， lexical errors （x?=67.765， df=1， p=.000< .05） and MF errors （x?=44.827， df=1， p=.000<.05）， more MF errors than phonological errors （x?=13.091， df=1， p=.000< .05）， while the teachers’ notice of phonological errors and lexical errors has no significant difference （x?=3.333， df=1， p=.068>.05）， and the teachers’ notice of MF errors than lexical errors has no significant difference （x?=3.630， df=1， p=.057>.05）.
The analyses above show that when teachers correct students’ errors， they pay much attention to FF errors. Detailed analysis shows that grammatical errors attract the most attention whichever the instruction it is; no MF errors are found in FF Instru.， and in MF Instru. and F&M Instru.， though MF errors occupy a small proportion of all the errors， their number is larger than that of phonological errors and lexical errors. The next part will focus on the relationship between students’ error types and teachers’ feedback types.
3.3 Relationship Between Feedback Types and Error Types
In this section， the relationship between feedback types and error types respectively in FF Instru.， MF Instru. and F&M Instru. will be investigated. Feedback types consist of explicit correction （Expli.C）， recast， and negotiation of form（Negotia.C）， and error types are divided into MF errors and FF errors which can be further divided into the phonological error， grammatical error and lexical error. Therefore， the three feedback types （Expli.C， recast， and Negotia.C） and the four error types （phonological， grammatical， lexical and MF error） are studied in this part. Tables 4-7 shows the distribution of error types across feedback types in the
data.
Table 7
Distribution of Feedback Types across Error Types
Phonological error （n=79） Grammatical error （n=336） Lexical error （n=73） MF error （n=108） Total （n=596）
Expli.C 15 19% 23 7% 6 8% 12 11% 56 9%
Recast 41 52% 184 55% 36 49% 14 13% 275 46%
Negotia.C 23 29% 129 38% 31 43% 82 76% 265 45%
Figure 6
Percentage of Feedback Types Across Error Types
Table 7 and Figure 6 show that the majority of feedback type following phonological errors and grammatical errors are recast （52%， 55% respectively）， the majority of feedback types following lexical errors are recast and Negotia.C （49%， 43% respectively）， and the majority of feedback type following MF errors is Negotia.C （76%）.
In FF Instru.， the teachers offer 72 tokens of corrective feedback to 72 FF errors. The 72 tokens of corrective feedback following initial errors are distributed across the 3 feedback types as follows： 13 tokens are Expli.C， 23 tokens involve recasting and 36 tokens are Negotia.C. The distribution of feedback types across error types in FF Instru. are showed in Table 8 and Figure 7.
Table 8
Distribution of Feedback Types Across Error Types in FF Instru.
Phonological error Grammatical error Lexical error Total
Expli.C 7 24% 4 14% 2 14% 13 18%
Recast 7 24% 15 52% 1 7% 23 32%
Negotia.C 15 52% 10 34% 11 79% 36 50%
Total 29 100% 29 100% 14 100% 72 100%
Figure 7
Percentage of Feedback Types Across Error Types in FF Instru.
Table 8 and Figure 7 show that in FF Instru.， no MF errors are found; 52% of the phonological errors are treated with Negotia.C， and 24% is treated with recast and Expli.C respectively; 52% of grammatical errors are treated with recast， 34% are treated with Negotia.C， and 14% are treated with Expli.C; 79% of the lexical errors are treated with Negotia.C， 14% are treated with Expli.C， and 7% are treated with recast.
The analyses above indicate the following patterns in FF Instru.： The majority of feedback type following phonological errors is Negotia.C， the majority of feedback type following grammatical errors is recast， and the majority of feedback type following lexical errors are Negotia.C.
In MF Instru.， the teachers provide the students with 344 corrective feedback moves. The 344 corrective feedback moves following initial errors are distributed across the three feedback types as follows： 26 tokens are Expli.C， 185 tokens are recast， and 133 tokens are Negotia.C. A comparison of the distribution of these feedback types across different error types is showed in Table 9 and Figure 8.
Table 9
Distribution of Feedback Types Across Error Types in MF Instru.
Phonological error Grammatical error Lexical error MF error Total
Expli.C 7 17% 9 5% 3 8% 7 9% 26
Recast 28 70% 124 65% 26 67% 7 9% 185
Negotia.C 5 13% 58 30% 10 25% 60 82% 133
Total 40 100% 191 100% 39 100% 74 100% 344
Figure 8
Percentage of Feedback Types Across Error Types in MF Instru.
Table 9 and Figure 8 show that in MF Instru.， 70% of phonological errors are treated with recast， and 17% are treated with Expli.C， and 13% are treated with Negotia.C; 65% of grammatical errors are treated with recast， 30% are treated with Negotia.C， and 5% are treated with Expli.C; 67% of lexical errors are treated with recast， 25% are treated with Negotia.C， 8% are treated with Expli.C; 82% of MF errors are treated with Negotia.C， 9% are treated with Expli.C and recast
respectively.
The analyses above indicate the following pattern in MF Instru.： The majority of feedback type following phonological errors， grammatical errors and lexical errors are recast while the majority of feedback type following MF errors is Negotia.C. That is to say in MF Instru.， when correcting FF errors， teachers tend to apply recast， and when MF errors are treated， Negotia.C is much more preferred.
In F&M teachers have provided the students with 180 corrective feedback moves. Among them， 17 tokens are Expli.C， 67 tokens are recast， and 96 tokens are Negotia.C. A comparison of the distribution of theses feedback types across different error types is showed in Table 10 and Figure 9.
Table 10
Distribution of Feedback Types Across Error Types in F&M Instru.
Phonological error Grammatical error Lexical error MF error Total
Expli.C 1 10% 10 9% 1 5% 5 15% 17
Recast 6 60% 45 39% 9 45% 7 20% 67
Negotia.C 3 30% 61 52% 10 50% 22 65% 96
Total 10 100% 116 100% 20 100% 34 100% 180
Figure 9
Percentage of Feedback Types Across Error Types in F&M Instru.
Table 10 and Figure 9 show that in F&M Instru.， 60% of phonological errors are treated with recast， 30% are treated with Negotia.C， and 10% are treated with Expli.C; 52% of grammatical errors are treated with Negotia.C， 39% are treated with recast， and 9% are treated with Expli.C; 50% of lexical errors are treated with Negotia.C， 45% are treated with recast， 5% are treated with Expli.C; 65% of MF errors are treated with Negotia.C， 20% are treated with recast， and 15% are treated with Expli.C.
The analyses above indicate the following pattern in F&M Instru.： The majority of feedback type following phonological errors are recast， the majority of feedback type following grammatical errors and lexical errors is recast and Negotia.C， and the majority of feedback type following MF errors are Negotia.C.
To sum up， the majority of feedback type following phonological errors and grammatical errors are recast， the majority of feedback types following lexical errors are recast and Negotia.C， and the majority of feedback type following MF errors are Negotia.C. As it is related to instruction types， in FF Instru.， teachers like to use Negotia.C to follow phonological errors and lexical errors， and recast to follow grammatical errors. In MF Instru.， teachers like to use recast to follow FF errors （phonological， grammatical and lexical errors） and Negotia.C is such as to follow MF errors. In F&M Instru.， teachers like to use recast to follow phonological errors， Negotia.C to be followed grammatical errors， and both Negotia.C and recast are preferred after lexical errors. When MF errors are handled， Negotia.C is a lot more preferred.
3.4 Relationship Between Feedback Types and Learner’s Uptake Types
4.3 presents a general picture of the relationship between feedback types and error types in FF Instru.， MF Instru. and F&M Instru. respectively. This part will focus on the relationship between feedback types and uptake types respectively in FF Instru.， MF Instru. and F&M Instru.. As the above mentioned， uptake is divided into two types： repair and needs-repair. Tables 4-11 display the results of examining the relationships between feedback types and uptake types.
Table 11
Distribution of Uptake Types Across Feedback Types
Repair Needs-repair Total
Number Percentage （%） Number Percentage （%）
Expli.C 31 55 25 45 56
Recast 92 33 183 67 275
Negotia.C 216 82 49 18 265
Total 339 57 257 43 596
Figure 10
Percentage of Uptake Types Across Feedback Types
Table 11 and Figure 10 demonstrate that recast， the most popular feedback type， brings about the lowest repair rate （33%）. The next one is Expli.C， the percentage of repair is 55%. The feedback type with the highest repair rate is Negotia.C， 82% of learner utterances following this type of feedback moves involved in uptake. In general， 57% of all feedback moves elicit repair， while 43% follow with needs-repair.
Tables 12-14 show the distribution of repair and needs-repair across feedback types in each instruction.
Table 12
Distribution of Uptake Types Across Feedback Types in FF Instru.
Repair Needs-repair Total
Number Percentage （%） Number Percentage （%）
Expli.C 9 70 4 30 13
Recast 12 52 11 48 23
Negotia.C 29 81 7 19 36
Total 50 69 22 31 72
Figure 11
Percentage of Uptake Types Across Feedback Types in FF Instru.
Table 12 and Figure 11 demonstrate that in FF Instru.， Negotia.C， which has been used the most frequently， brings about the highest repair rate （81%） as well. The next one is Expli.C， the percentage of repair is 70%. The feedback type with the lowest repair rate is recast， with the repair rate of 52%. In general， 69% of all feedback moves elicit learner repair， while 31% follow with the
needs-repair.
Table 13
Distribution of Uptake Types Across Feedback Types in MF Instru.
Repair Needs-repair Total
Number Percentage （%） Number Percentage （%）
Expli.C 12 46 14 54 26
Recast 44 24 141 76 185
Negotia.C 110 83 23 17 133
Total 166 48 178 52 344
Figure 12
Percentage of Uptake Types across Feedback Types in MF Instru.
Table 13 and Figure 12 show that in MF Instru.， the repair rates after recast and Expli.C are much lower than Negotia.C. Recast， though used most frequently， brings about the lowest repair rate （24%）. Expli.C， with the repair rate of 46%， comes after Recast. The feedback type with the highest repair rate is Negotia.C， with the repair rate of 83%. In general， 48% of all feedback moves elicit learner repair， while 52% follow with needs-repair.
Table 14
Distribution of Uptake Types across Feedback Types in F&M Instru.
Repair Needs-repair Total
Number Percentage （%） Number Percentage （%）
Expli.C 10 59 7 41 17
Recast 36 54 31 46 67
Negotia.C 77 80 19 20 96
Total 123 68 43 32 180
Figure 13
Percentage of Uptake Types Across Feedback Types in F&M Instru.
Table 14 and Figure 13 display that in general， 68% of all feedback moves in F&M Instru. elicit learner repair， while 32% in F&M Instru. follow with needs-repair. To be more specific， the feedback type with the highest repair rate is Negotia.C， 4/5 of the learner utterances following this type of feedback moves involve repair. The feedback type with the second highest repair rate comes to Expli.C， with the repair rate of 59%. Recast， which has been used much more frequently than Expli.C， brings about the lowest repair rate （54%）.
The analyses above suggest that in general， recast， which has been most frequently used， brings about the lowest repair rate; the feedback type with the highest repair rate is Negotia.C. The repair rate of the three feedback types in each instruction occur in accordance with the repair rate of the three feedback types in general， that is， in the three instructions， Negotia.C brings about the highest repair rate， followed by Expli.C and recast respectively. The total repair rate in MF Instru. （48%） is lower than that in FF Instru. （69%） and F&M Instru. （68%）. Interestingly， the repair rates of Negotia.C in the three instructions are close to one another （81% in FF Instru.， 83% in MF Instru.， 80% in F&M Instru.）， the repair rates of Expli.C （59%） and recast （54%） in F&M Instru. are very close to each other， and the repair rates of Expli.C （46%）， recast （24%） and Negotia.C （83%） are strongly different from one another in both MF Instru..
CONCLUSION
The present study has focused on the issue： how teacher’s corrective feedback is related to the focus of instruction. According to different focuses， instruction can be grouped to three types： form-focused instruction （FF Instru.）， meaning-focused instruction （MF Instru.） and both-form-and-meaning-focused instruction （F&M Instru.）. The following conclusion can be drawn from the results and discussions of the previous chapter.
Firstly， MF Instru. invites the most CFSs， followed by F&M Instru. and FF Instru. respectively. This finding goes against the statement by Jack Richards （1986） that error correction should be avoided in communication unless error hinders communication process. That is， teachers offer feedback without taking instruction focus into consideration.
Secondly， when teachers correct students’ errors， they pay much more attention to FF errors than to MF errors. In MF Instru. and F&M Instru.， though MF errors occupy a small proportion of all the errors， their number is larger than that of phonological and lexical errors. Grammatical errors attract the most attention whichever the instruction it is.
Thirdly， recast and Negotia.C is much more preferred than Expli.C as a whole. When error types are taken into consideration， the majority of corrective feedback type following phonological and grammatical errors is recast， the most feedback types following lexical errors come to recast and Negotia.C， and the majority of feedback type following MF errors are Negotia.C. As it is related to instruction types， in FF Instru.， Negotia.C is more frequently used than Expli.C in general; teachers prefer to use Negotia.C to follow phonological and lexical errors， and recast to follow grammatical errors. In MF Instru.， recast is most frequently utilized， followed by Negotia.C and Expli.C respectively; teachers like to use recast to follow FF errors （grammatical， phonological and lexical errors）， and Negotia.C is such as to follow MF errors. In F&M Instru.， recast and Negotia.C are more frequently used than Expli.C; teachers prefer to use recast to follow phonological errors， Negotia.C to be followed grammatical errors， and both Negotia.C and recast are preferred after lexical errors. When MF errors are handled， Negotia.C is much more preferred than Expli.C and recast.
Fourthly， in general， recast， the most popular feedback type， brings about the lowest repair rate， while the feedback type with the highest repair rate is Negotia.C. The repair rate of Expli.C， recast and Negotia.C in the three instructions ranks in the same order as in the general situation， that is， Negotia.C invites the most repair， followed by Expli.C and recast respectively in FF Instru.， MF Ibstru. and F&M Instru..
PEDAGOGICAL IMPLICATION
The findings of the present study seem to suggest the following two pedagogical implications：
First， when offering corrective feedback， teachers should take focus of instruction into consideration. In meaning-focused instruction （MF Instru.）， teachers should allow certain linguistic deviation to go uncorrected so long as the error does not impede the flow of communication. When teaching focuses on form accuracy， teacher had better use negotiation of form （Negotia.C） to encourage students’ correction in the provision of corrective feedback. It may not be effective for teachers to offer recast after students’ errors. Besides， the learners are capable of correcting themselves if they are given sufficient time and their attention is called upon to the form.
Second， teachers should conduct more activities which aim at accuracy as well as fluency and communication， in which the learner may have more opportunities to speak in the target language and also have more chances to commit errors which inform teachers of their learning stage and help them diagnose learning difficulties， because the analysis in 4.4 have indicated that the errors treated in the instruction focusing on both form and meaning get higher rate of uptake than in the one only focusing on meaning. As we know， communication is the goal of language teaching and at the same time it should be part of the learning process. In doing so， the learners can make formally learnt language more automatically available; they can acquire language subconsciously during meaningful communication， and when they are making effort to communicate， they develop strategies of communication which help them to learn.
REFERENCES
Chaudron， C. （1988）. Second language classrooms： Research on teaching and learning. Cambridge： Cambridge University Press.
Ellis， R. （1994）. The study of second language acquisition. Oxford University Press.
Jack， C. R.， & Rodgers， T. S. （1986）. Approaches and methods in language teaching. Cambridge University Press.
Lyster， R. （1998a）. Recast， repetition and ambiguity in L2 classroom discourse. SSLA， 20， 51-81.
Shi， G. （2005）. Teachers’ error correction and students’ acception in English class. Foreign Language and Literature， 4， 242-248.
Tang， J. Y. （2003）. Teachers’ error correction’s impact on the students’ acquisition uptake in English class （Master’s Thes）. South China Normal University.
Zhao， C. （2005）. Teachers’ corrective feedback of different level of English teaching―A Study based on corpus. Journal of PLA Foreign Languages Institute， 3， 35-44.
第9篇：米尔恩范文
双胞胎兄弟出生隔8天 弟救哥一命化险为夷
一名来自百慕大的孕妇，日前在加拿大哈利法克斯一家医院产下双胞胎兄弟，但两兄弟出生时间相隔8天，被称为“奇迹双胞胎”。据报道，埃多娜怀孕18周时，双胞胎哥哥埃米尔羊膜囊破裂，埃多娜被迅速送往医院。在埃多娜入院2周后，埃米尔出生。接着埃多娜的宫缩减弱了，弟弟埃塞似乎很喜欢待在妈妈的子宫里。医师担心把埃米尔的胎盘留在子宫内会使埃多娜感染，于是进行手术。在哥哥出生后8天，弟弟终于出生了。创造这一奇迹的大功臣是埃塞，很有可能是他挽救了哥哥的生命。埃多娜说：“实际上，是埃塞撑起我的子宫，让埃米尔可以继续成长。”目前，这对双胞胎还在新生儿重症监护室里，状况良好。
点评：这哥儿俩在娘胎里就不离不弃，长大后，肯定更会生死相依吧。
6岁小孩想当宇航员 向白宫请愿增经费
由于自小梦想成为一名宇航员，6岁的康纳・约翰逊目前在“白宫请愿网站”上发起了一项请愿活动，请求白宫为美国宇航局增加经费。康纳解释，之所以有这样的梦想，是因为他觉得太空有太多新奇的东西。直到最近，康纳听说美国国会威胁削减美国宇航局的经费，减少空间探索项目。在他看来，这极有可能威胁他“未来的职业生涯”，于是，他决定帮助美国宇航局，让白宫收回决定。康纳已成功拿到了近15000个签名，但签名要超过10万个，白宫才会回应他的提案。虽然这是个艰巨的任务，但康纳很乐观，认为自己能够完成使命。
点评：孩子的梦想永远令人敬畏，因为它有实现的无限可能。
科技
葡萄牙西边发现海底金字塔 疑似亚特兰提斯遗迹
失落的亚特兰提斯帝国传说一直是个谜团，日前，在葡萄牙西边的亚速群岛，一名渔夫以声呐探测法，在特塞拉岛和萨欧米格岛之间，发现了这座高度有60米、宽达8000米的海底金字塔，它位于海面下40米，四面棱线刚好朝向正东、正西、正南与正北，和吉萨的大金字塔类似，发现者认为这绝对不是自然形成的。这座海底金字塔会不会是所谓“失落的帝国”――亚特兰提斯的遗迹呢？在发现海底金字塔消息传出之后，这里也让考古学家和古文明的研究者更加好奇。
点评：失落的文明古国，永远令人好奇。
手机蓝光能给大脑提神 比咖啡因灵？
蓝光最近得到了一个坏名声，那就是影响睡眠。报道称，入睡前使用智能手机和其他电子设备会影响睡眠，因为它们发出的光会产生一种抑制褪黑激素的化学物质，从而控制人体的生物钟。然而日前披露的一项研究表明，蓝光也有一些优点，那就是在正确的时间里使用，可以使大脑更加清醒。瑞典中部大学的研究人员比较了咖啡因和蓝光对大脑的影响，发现它们都有积极的作用。有趣的是，人们暴露在蓝光下，大脑功能的测试表现更为出色。在相同条件下，使用更多咖啡因的测试人员则表现不佳。研究表明，蓝光可以提高认知能力，如记忆、警觉性和反应时间。这项技术将可以用于医学治疗。
点评：以后玩手机就更有理由了。可是，这靠谱吗？
萌宠
猫头鹰携钻戒“潜逃”险坏新人婚事
结婚戒指随猫头鹰从天而降，这样的婚礼是不是很特别？日前，英国一对新婚夫妇在婚礼上让一只猫头鹰充当拿戒指的“花童”，但就在婚礼当天，这只鸟儿却耍起了“脾气”。这对来自英国兰开夏郡的夫妻名叫克莱尔和安德鲁・波德。为了让婚礼显得“与众不同”，他们租了一只名叫“丽萝”的谷仓猫头鹰，并在婚礼当天让丽萝从空中飞落并献上婚戒。但这只鸟儿在婚礼现场并没有听话地落在红毯上，而是飞到了房梁上不肯下来。幸运的是，在驯鸟人的帮助下，他们最终用小鸡将丽萝哄了下来。丈夫安德鲁说，他的妻子是《哈利・波特》的忠实粉丝，她想将这一点体现在他们的婚礼上，所以想到了猫头鹰。这对夫妻还说，这一插曲让他们的婚礼着实令人难忘。
点评：这猫头鹰是想抢头条的节奏吗？是不是想把戒指送给另一只呢？
台湾猕猴杀鸡儆人？
宜兰一家养鸡场为阻止猕猴侵入鸡舍偷吃饲料，特别加设围篱，未料装设后两天内竟有50多只鸡遭屠杀，鸡脖也被扭断，损失近3万元。养鸡场主人气愤地说：“一定是猴子要报复我！故意虐杀鸡，甚至排成鸡尸堆挑衅。”宜兰冬山乡的养鸡场主人江佩琳说，周日上午与儿子到养鸡场察看时，发现养鸡场角落有20只鸡的尸体，除脖子被扭断，身上还有被咬的伤口，由于养鸡场设有围篱，野狗进不来，当时就怀疑凶手是猴群，但因找不到证据，只能认赔，没想到隔天养鸡场又有30几只鸡在鸡舍遭到集体屠杀。
点评：都说杀鸡给猴看，俺偏要杀鸡给人看。呜呜，谁让你不让俺吃东西来着？
奇趣
新加坡建筑师打造水上全景漂浮屋
日前，新加坡建筑师Myitr Malcew为法国浮动结构开发公司H2ORIZON设计出一种水上全景漂浮屋，为人们带来不一样的海上居住享受。这种漂浮屋是建造在一个有浮力的平台上，有两间卧室、两间浴室、一个大客厅和一个有吧台的厨房，外面有一个大露台。整个房子靠几根柱子支撑，并且全部是玻璃落地窗，这使得屋顶看起来像是漂浮在上面。这种漂浮屋的结构非常灵活，屋主可以根据自己的喜好把房子停靠在任何地点。它最独特的设计点是无论屋主选择在哪里停驻，它都可以让屋主拥有超级美丽的全景视野。但屋外可移动的屏风和木质可滑动的面板又可以保护屋内居民的隐私。
点评：只有想不到，没有做不到。在水上住着，肯定够浪漫。
美国女子追求另类 在眼中植入白金饰物
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