腕关节软骨板生物力学特征研究     

李雪  沙川华  陈孟诗 《体育科学》2007,27(7):51-54

目的：腕关节软骨板为桡尺远侧关节与腕关节共同拥有的结构，具有缓冲尺骨小头与腕骨间的直接压力，分散载荷等作用。该结构为纤维软骨，在运动中不断承受着来自各方向的拉伸、挤压、剪切等力量，容易发生急性损伤与慢性劳损。方法：通过对新鲜腕关节软骨板共计60个试件进行不同应变水平下的“应力松弛试验”和等应变速度下的“拉伸试验”，了解腕关节软骨板在承受一维拉伸破坏试验时的力学性质，并用拟线性粘弹性理论对试验结果进行分析，建立了腕关节软骨板的本构方程。结果：腕关节软骨板的应力松弛程度较低，初始应力松弛率在8％～15％左右；腕关节软骨板的本构方程为：腕骨面为：σ^e（ε）=1.111（e^1.923k-1），尺骨面为：σ^e（ε）=1.111（e^2.904ε-1）；腕关节软骨板腕骨面与尺骨面力学性能差异不大。结论：急性运动损伤及其慢性劳损的发生与软骨板的部位关系不大，主要与腕关节受到打击的角度、关节运动的幅度以及使关节运动的肌肉工作性质等有关。  相似文献   

Water-repellent and biocide treatments: Assessment of the potential combinations   总被引：1，自引：0，他引：1  

Claire Moreau  Vronique Vergs-Belmin  Lise Leroux  Genevive Orial  Gilles Fronteau  Vincent Barbin 《Journal of Cultural Heritage》2008,9(4):394-400

It is a common practice to use several chemical products during restoration projects of monuments or sculptures. However, care must be taken when combining the products to avoid a misuse. For example, it is well-known that applying a biocide on stone before a water-repellent leads to a diminishment of the hydrophobic effect of the treatment. But the application of biocide after a water-repellent treatment has been poorly analysed, although studies have proven that the stone looses its hydrophobicity after the application of the biocide. Henceforth, this study investigates the effects of biocide application on a water-repellent film and focuses on the possibilities to restore the efficiency of the previous water-repellent treatment (after the application of the biocide). At first, the tests were performed on glass slides to understand the mechanisms, with the subsequent results revealing that the biocide product deposits on the water-repellent film. Then, the study focuses on determining methods to remove the remains of biocide on limestone samples, previously treated with a water-repellent. The water-repellent used in the study is an alkylpolysiloxane, Rhodorsil H224 from Rhodia.  相似文献   

Standardization and UNDERSTANDardization in Educational Assessment     

Stephen G. Sireci 《Educational Measurement》2020,39(3):100-105

Educational tests are standardized so that all examinees are tested on the same material, under the same testing conditions, and with the same scoring protocols. This uniformity is designed to provide a level “playing field” for all examinees so that the test is “the same” for everyone. Thus, standardization is designed to promote fairness in testing. In practice, the material tested, the conditions under which a test is administered, and the scoring processes, are often too rigid to provide the intended level playing field. For example, standardized testing conditions may interact with personal characteristics of examinees that affect test performance, but are not construct-relevant. Thus, more flexibility in standardization is needed to account for the diversity of experiences, talents, and handicaps of the incredibly heterogeneous populations of examinees we currently assess. Traditional standardization procedures grew out of experimental psychology and psychophysics laboratories where keeping all conditions constant was crucial. Today, accounting for and measuring what is not constant across examinees is crucial to valid construct interpretations. To meet this need I introduce the concept of understandardization, which refers to ensuring sufficient flexibility in standardized testing conditions to yield the most accurate measurement of proficiency for each examinee.  相似文献   

一道中考题的探究与思考     

陈为镜 《宁德师专学报(自然科学版)》2010,22(1):81-83,86

通过对2009年福州市中考一道数学试题的探析,分析学生答卷以及学习中存在的问题,探讨培养学生解题能力与总复习备考的建议.  相似文献   

The Analysis of Usefulness in CET4 Writing Subtest     

赵瑞 《读与写:教育教学刊》2010,7(8):15-16

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台湾施行社会证书考试的历史与经验研究     

张庆守 《闽江学院学报》2012,33(1):109-113,124

台湾社会证书考试的历史发展经历萌芽开创、拓展推进和调整深化三个阶段。在发展过程中，台湾当局有关部门重视考试法制建设，把综合素质和实务能力列为考评重要内容，建立统一的考试管理机制，优化考试影响因子配置，并采取多种措施提高证书的效用性和权威性。中国大陆开展社会证书考试可从台湾地区相关领域的历史发展及做法中汲取诸多经验教训。  相似文献   

A simple survey kit for chloride detection on cuneiform tablets and other collections     

Dennis Piechota  Jane Drake Piechota 《文物保护研究》2016,61(1):58-61

This technical note describes the construction and use of a portable silver nitrate test kit designed to be safely usable in the storeroom during collection condition surveys. It provides the surveying conservator with supplementary test data to better predict the level of hazard presented by soluble salts in collections.  相似文献   

An NCME Instructional Module on Subscores     

Sandip Sinharay  Gautam Puhan  Shelby J. Haberman 《Educational Measurement》2011,30(3):29-40

The purpose of this ITEMS module is to provide an introduction to subscores. First, examples of subscores from an operational test are provided. Then, a review of methods that can be used to examine if subscores have adequate psychometric quality is provided. It is demonstrated, using results from operational and simulated data, that subscores have to be based on a sufficient number of items and have to be sufficiently distinct from each other to have adequate psychometric quality. It is also demonstrated that several operationally reported subscores do not have adequate psychometric quality. Recommendations are made for those interested in reporting subscores for educational tests.  相似文献   

经济增长与违法用地的关系分析   总被引：3，自引：1，他引：2  

刘法威 《资源科学》2010,32(8):1558-1562

现阶段,协调好经济增长和违法用地的矛盾是实现我国可持续发展战略的重要基础。通过运用Granger因果检验方法,利用1999年-2007年间的省际面板数据验证了经济增长与违法用地之间的因果关系。研究结果表明,在滞后1期,经济发展与违法用地之间存在双向因果关系;在滞后2期,经济发展与违法用地之间不存在因果关系。具体而言:在经济增长的初级和中级阶段,经济增长是违法用地的诱因;在经济增长的高级阶段,经济增长与违法用地之间不存在因果关系,这是由于一方面经济增长不再依靠土地要素投入的增加,另一方面违法用地的大面积蔓延反倒会对经济发展质量产生不利影响。这一研究的政策启示是,目前以及今后一段时间内,土地违法现象仍然会存在。既要充分利用违法用地对经济增长的推动效应,而且需要采用经济、行政、技术等各种手段,将违法用地遏制在一个合理的范围内,以便更好地为我国的经济增长服务。  相似文献   

散打运动员肘关节的等速肌力研究          下载免费PDF全文

吴继魁 《河北体育学院学报》2016,30(3):86-90

采用ISOMED2000等速力量测试系统对优秀散打运动员和一般散打运动员肘关节进行不同速度的等速肌力测试.测试速度依次为10°/s、60°/s、180°/s和360°/s,选取屈肌肌群、伸肌肌群的峰值力矩、峰值力矩体重比、屈伸肌比值、峰力矩角度、平均功率、总功作为指标,对运动员的肘关节肌肉力量进行研究,比较分析不同速度下肘关节屈伸肌群的力学特征变化.结果显示,优秀运动员无论绝对力量、相对力量还是爆发力都高于一般运动员,优秀运动员在60°/s速度时峰力矩、相对峰力矩和做功最大,但优秀运动员的伸肌力量明显大于屈肌力量,可能出现关节不稳定.  相似文献