Effects of Written Corrective Feedback on College EFL Students’Writing Accuracy and Linguistic Knowledge Acquisition

Set at the interface between second language acquisition and second language writing,this study examines how different types of written corrective feedback(WCF)influence the writing accuracy of Chinese college students learning English as a Foreign Language(EFL)and whether WCF facilitates the students’grasp of the focused linguistic knowledge.The participants(n=60)were divided into direct correction group(n=20),indirect error-coding group(n=20)and metalinguistic explanation group(n=20).The three groups wrote four essays in two months and received WCF for the first three essays on the five targeted error types,namely tense errors,confusion of different forms of a word,word(articles,prepositions,etc.)missing,errors in subjectverb agreement and inappropriate verb-noun collocations.The results show that all three types of WCF improved students’writing accuracy but none of them had any statistical advantage,and the metalinguistic WCF was more effective than the other two forms in facilitating the acquisition of the targeted linguistic features.These results shed some light on teaching and consolidation of language points through writing in EFL contexts.

Impact Analysis of Off-board Charger to Power Quality

In this paper, we tested the entire charging process of a single off-board charger in one charging station in Beijing. Among the testing data, we chose the typical power quality parameters and compared them with national standard. Then we drew conclusions as follows: 1) Electric vehicle battery is the capacitive load. It can export reactive power when charging. 2) In the charging process of the off-board charger, indicators of voltage deviation, frequency deviation, power factor, and voltage distortion rate are qualified. 3) Off-board charger produces odd harmonics in the charging process, and with increasing harmonic order, harmonic content reduces. There is a certain amount of high-order harmonic in off-board charger, mainly distributing around 6650 kHz. 4) Generated harmonics of the actual device, the harmonic is mainly reflected in the current, voltage, only a small distortion.

两种宫腔粘连大鼠模型稳定性的比较

目的比较无水乙醇化学损伤法、刮宫与宫腔留置脂多糖双重损伤法建立SD大鼠宫腔粘连动物模型的造模效果,探索模型稳定性。方法110只SD雌鼠采用随机数表随机分为正常组、双重损伤组和无水乙醇组。正常组每组30只,余两组均为40只。无水乙醇组宫腔注射95%无水乙醇损伤子宫内膜,双重损伤组刮宫后宫腔留置脂多糖棉线2 d损伤子宫内膜,正常组行假手术。分别于术后1周、2周、4周、8周、12周采用随机数表每组各随机抽取3只动物收集子宫组织,行HE染色和Masson染色,对子宫内膜厚度、腺体数量和纤维化面积进行统计分析,并行免疫组织化学染色观察CD31在子宫内膜间质上的表达情况。结果①两种模型子宫内膜厚度在造模2周后,均小于正常组,且趋于稳定。无水乙醇组子宫内膜厚度较双重损伤组减少更明显(P均<0.05)。②两种模型子宫内膜腺体数量在造模1周后均明显小于正常组,无水乙醇组子宫内膜腺体数量较双重损伤组减少更明显(P均<0.05)。③两种模型子宫内膜间质纤维化面积在造模1周后均高于正常组(P均<0.05),但无水乙醇组纤维化面积在造模后8周开始减少。④两种模型子宫内膜间质CD31表达量在造模1周后均明显小于正常组(P均<0.05),无水乙醇组较双重损伤组减少更明显(P均<0.05)。⑤2周和12周模型鼠妊娠情况及胎鼠数目比较表明模型鼠生育能力均受到影响,且无水乙醇组模型鼠生育能力所受影响比双重损伤模型组明显。结论两种方法均能诱导宫腔粘连;无水乙醇化学损伤法操作较简单、经济,但纤维化稳定性欠佳,其子宫内膜厚度、腺体数量及血管改变符合薄型子宫内膜病理变化,更适用于薄型子宫内膜疾病的相关研究;双重损伤模型贴近临床损伤方法,且模型更稳定,可以满足宫腔粘连相关研究需求。