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初中学生实验操作考查方法的研究
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作者 徐义明 刁世智 尹凤竹 《当代教育科学》 1994年第1期41-44,共4页
一、当前考查模式综述 近几年来,全国不少学校对学生实验操作能力考查的方式方法进行了研究探讨。基本模式是:题目综合,覆盖各科,考题公开,全面操作,抽签定题,对号入座,一师一生,全程监测,分数评定,依据细则。详细讲一下就是:题目多半... 一、当前考查模式综述 近几年来,全国不少学校对学生实验操作能力考查的方式方法进行了研究探讨。基本模式是:题目综合,覆盖各科,考题公开,全面操作,抽签定题,对号入座,一师一生,全程监测,分数评定,依据细则。详细讲一下就是:题目多半是综合性的,在30分钟内即可完成,要求覆盖操作内容尽量多,在考试前向学生公布试题,让学生在实验室充分全面地练习。考试时让学生抽签,决定做那个题目; 展开更多
关键词 实验操作考查 初中学生 评分 监考者 分数评定 装片 偶然误差 加分 实验考查 考查方法
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Three-dimensional analysis of slopes reinforced with piles 被引量:10
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作者 高玉峰 叶茂 张飞 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2322-2327,共6页
Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of... Based on the upper bound of limit analysis, the plane-strain analysis of the slopes reinforced with a row of piles to the 3D case was extended. A 3D rotational failure mechanism was adopted to yield the upper bound of the factor of safety. Parametric studies were carried out to explore the end effects of the slope failures and the effects of the pile location and diameter on the safety of the reinforced slopes. The results demonstrate that the end effects nearly have no effects on the most suitable location of the installed piles but have significant influence on the safety of the slopes. For a slope constrained to a narrow width, the slope becomes more stable owing to the contribution of the end effects. When the slope is reinforced with a row of piles in small space between piles, the effects of group piles are significant for evaluating the safety of slopes. The presented method is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of plies stabilizing the unstable slopes. 展开更多
关键词 three-dimensional rotational failure mechanism stability of slopes limit analysis LANDSLIDES PILES
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Reliability evaluation for Weibull distribution under multiply type-? censoring 被引量:1
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作者 贾祥 蒋平 郭波 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3506-3511,共6页
The multiply type-I censoring represented that all units in life test were terminated at different times. For estimations of Weibull parameters, it was easy to compute the maximum likelihood estimation (MLE) and lea... The multiply type-I censoring represented that all units in life test were terminated at different times. For estimations of Weibull parameters, it was easy to compute the maximum likelihood estimation (MLE) and least-squares estimation (LSE) while it was hard to build confidence intervals (CI). The concept of generalized confidence interval (GCI) was introduced to build CIs of parameters under multiply type-I censoring. Further, GCI based on LSE and GCI based on MLE were proposed. It is mathematically proved that the former is exact and the latter is approximate. Besides, a Monte Carlo simulation study and an illustrative example also Ran out that the GCI method based on LSE yields rather satisfactory results by comparison with the ones based on MLE. It should be clear that the GCI method is a sensible choice to evaluate reliability under multiply type-I censoring. 展开更多
关键词 multiply type-I censoring generalized confidence interval maximum likelihood estimation least-squares estimation
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