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31.
本文研究了在室温下微波催化合成二糠叉环己酮的优化工艺条件。结果表明:糠醛与环己酮摩尔比2:1,功率为320W,反应2分钟时,二糠叉环己酮的产率最大,可达90.2%。 相似文献
32.
对恢复高考英语听力测试的思考 总被引:2,自引:0,他引:2
自2000年以来,我国开始在高考英语试题中逐渐推广听力测试,2003年高考英语听力测试在全国普及,促进了基础教育阶段学生英语听力水平的提高。但2005年起出现了部分省区取消或淡化高考英语听力的现象。本文探讨了此举的原因、危害,建议尽早恢复高考英语听力测试,发挥高考对基础英语教育的正面反拨作用,为培养学生的英语交际能力打下基础。 相似文献
33.
孟祥武 《辽宁师范大学学报(社会科学版)》2005,28(3):94-96
新中国成立后,茅盾主要致力于艺批评工作。这里着重从捕捉鲜明个性、驾驭思想艺术、运用对照比较和散美的笔调等4个方面探求茅盾对17年作家作品论的魅力,从而有益于今天的艺批评。 相似文献
34.
Timothy M. McGrath Gordon Waddington Jennie M. Scarvell Nick B. Ball Rob Creer Kevin Woods 《Journal of sports sciences》2016,34(4):289-302
Lower limb dominance (or lateral preference) could potentially effect functional performance. Clinicians are often asked to make judgements as to when a patient has sufficiently “recovered” from an injury, typically using strength and dynamic performance outcome measures. The primary purpose of this study was to systematically review the literature in relation to limb dominance within active adult populations and discuss some limitations to current methods and relate this to current clinical practice. A search of MEDLINE and CINAHL and EMBASE databases and reference lists of those articles identified was performed. Eleven articles were selected for meta-analysis. There was no statistical effect of limb dominance for any of the functional tests: isokinetic quadriceps and hamstring tests, hamstring:quadriceps ratios, single-leg hop for distance, single-leg vertical jump and vertical ground reaction force following a single-leg vertical jump. Pooled symmetry values varied from 94.6% to 99.6% across the tests, above the clinically accepted benchmark of 90% used in clinical practice. Although the results of this study must be used with discretion, asymmetries in the tasks described in this analysis should be viewed as undesirable and remedied accordingly. Further research is needed to quantify asymmetries, particularly in relation to sport-specific contexts. 相似文献
35.
目的:采用功能性动作测试系统(Functional Movement Screen,FMS)评价青少年在完成不同功能动作模式时身体各部分的稳定性、对称性和灵活性,研究其基本运动能力及影响因素。方法:以上海市某中学中随机挑选的100名初中生为研究对象,对他们进行7个特定动作的测试并评分,并对测试结果进行统计分析。结果:FMS测试总分满分为21,受试对象FMS总分均分为14.89,总体水平偏低;女生肩关节灵活性和直腿抬高测试得分显著高于男生,但总分上男女生无显著差异;青少年在完成动作时普遍存在身体晃动、力量不足和两侧肌力不对称现象,髋、膝、踝关节灵活性受限且稳定性较差,脊柱的屈伸能力不足,两侧盂肱关节和髋关节的活动能力不对称。在旋转稳定性、跨栏架和直线弓箭步3个测试中这些不足尤为明显。结论:青少年基本运动能力水平较低,大多数人需要进行矫正训练;男女生总体上的表现差异不显著,但女生在肩部灵活性和直腿抬高测试的表现要优于男生,故男生需加强肩部和髋部关节的灵活性锻炼。 相似文献
36.
Partial discharge test on a transformer is carried out according to the items in IEC 60.During the test,unproved measuring system is calibrated by proved system at a voltage no less than 50% the rated testing voltage.The result is then extrapolated linearly,leading to an error related to the distribution of stray capacitance,which varies with the testing frequency,especially to large transformers.In this paper a factor,named the capacitive rise fact,is introduced to assess the rise.The factor can be adjusted to some extent by changing the reactance that is connected to the LV side of the testing circuit to lower the capacity of the power source.However,the factor changes when the voltage divider on the high voltage side is removed after the voltage ratio has been calculated,and a great error is resulted under unfavorable conditions. 相似文献
37.
张佳颖 《北京工业职业技术学院学报》2005,4(3):62-63
在阐明语言发展基本理论的基础上,简要论证了古英语时期(450-1150)英语和汉语的发展历程,并进行了初步的比较研究. 相似文献
38.
Lee Ingle Ashlie Stephenson Gavin R. Sandercock 《European Journal of Sport Science》2016,16(8):1187-1196
The aim of the study was to compare and contrast habitual physical activity (PA) profiles and muscular fitness in schoolchildren from northern and southern regions of England. Data were collected from two secondary schools in the north east (NE) of England. The study procedures followed methods employed by the East of England Healthy Hearts Study in 10–16-year-old boys and girls based in the south east (SE) region of England and data were compared. Habitual physical activity (PAQ-A), vertical jump test, and hand-grip (HG) strength were assessed. We converted raw scores from all assessments to age- and sex-normalised z-scores. We recruited 597 children (58% boys) in the NE and compared findings to 597 age- and sex-matched boys and girls from the SE. Boys in the SE had significantly stronger HG scores, jumped higher, were more powerful (mean peak power: 2131?W vs. 1782?W; P?0.0001), and reported being more physically active (mean PAQ-A: 2.9 vs. 2.5; P?0.0001) than their male counterparts in the NE. In girls, the opposite trend was evident. Girls from the NE of England had a higher HG score, jumped higher, and were more powerful (mean peak power: 2114?W vs. 1839?W; P?.0001) than their peers from the SE. Regional variations in the habitual PA profiles and muscular fitness of schoolchildren from the SE and NE of England do exist. The systematic surveillance of children’s PA and fitness profiles throughout England would help identify regional inequalities on a larger scale. 相似文献
39.
薛维 《三门峡职业技术学院学报》2003,2(1):22-24
讨论了国内英汉语言对比研究中很少涉及的一个研究层面———语篇对比,介绍了英汉两种语言在语篇对比中一个非常有实用价值的模式—主位—述位推进模式,希望引起更多的同行对这一领域研究的关注。 相似文献
40.
李煜的<虞美人>和李清照的<武陵春>历来受人推崇,被认为是写愁词的千古绝调. 从此中可略窥其抒愁风格之一斑.真是作之凄然,读之怆然.就两人前后际遇的迥异,两首词内容和表现手法的分析,男女词人的不同情感表现来探讨二人的言愁,其愁各有千秋,深广、凄绝两由之.但基调和意蕴均一样荡人心魂,具异曲同工之妙. 相似文献