“985”高校招生区域公平研究——基于洛伦兹曲线和基尼系数

本文认为,运用洛伦兹曲线和基尼系数分析“985”高校在各省区招生情况可以发现,尽管“985”高校总体上在各省区招生比例的分配较为公平,但是具体到各“985”高校却很不公平。主要原因是“985”高校招生属地化倾向严重,在本省区招生比例太大。此外,某些省区间交换招生计划的问题也不容忽视。     

T_d群的E矩阵表示及T_d对称性系统e声子间耦合的CG系数计算

计算了T_d群下不可约表示E的矩阵表示,探讨了具有T_d对称性系统e声子间耦合的CG系数计算问题,利用群论与对称性分析等数学方法导出了e声子间耦合的CG系数计算公式,最后用所得到的计算公式计算出了这些CG系数值.     

概率统计教学中若干问题的辨析

针对概率统计教学中发现的学生容易混淆和易弄错的几个问题,通过具体实例进行了深入探讨和剖析.     

C~n中球垒域上立体角系数的估计

给出Cn中N-球垒域D的边界点t的立体角系数αξtξ的计算方法,证明了0<αξtξ<1。     

有理函数分解成部分分式的几种方法

本文介绍了将有理函数分解成部分分式的实根代入法、复根代入法、极限法、求导法等几种简单方法,简捷有效地解决了有理函数的积分问题。     

IRS分析法中项目顺序系数的计算机优化算法及实现

IRS分析法是一种教育信息处理方法,它是在得分数据基础上对项目的关联程度进行排序的一种分析方法。目前的实践应用中没有一种快捷的方式生成IRS分析法中的关联矩阵以便于IRS图的形成,笔者利用VBA实现IRS中项目顺序系数算法以便于IRS图计算机自动生成,为IRS分析方法的快捷处理提供方便。     

The Correlation between Two Random Variables in a Coin‐Tossing Experiment

We find the correlation of two jointly distributed random variables connected with a coin tossing experiment. The marginal distributions are binomial and negative binomial.     

基于同类型日思路的节假日电力负荷预测方法

针对节假日负荷预测的特点,从同类型日与基准日的选择思路进行了分析,并据此提供了相应的实用预测方法,使预测较为准确,为电力行业从事预测的人员提供算法参考。     

电导法测定水溶液中NaBr与KBr的活度系数

应用电导法分别测定水溶液中NaBr、KBr的电导率,以及混合电解质NaBr和KBr的电导率;计算了电解质的活度系数。结果表明,温度一定时,在稀溶液范围内,活度系数随浓度的增加而降低;浓度一定时,随温度的升高而降低;混合电解质的活度系数与单一电解质的活度系数相近,并不存在简单的加和关系。     

Measurement of boiling heat transfer coefficient in liquid nitrogen bath by inverse heat conduction method

Inverse heat conduction method （IHCM） is one of the most effective approaches to obtaining the boiling heat transfer coefficient from measured results. This paper focuses on its application in cryogenic boiling heat transfer. Experiments were conducted on the heat transfer of a stainless steel block in a liquid nitrogen bath, with the assumption of a 1D conduction condition to realize fast acquisition of the temperature of the test points inside the block. With the inverse-heat conduction theory and the explicit finite difference model, a solving program was developed to calculate the heat flux and the boiling heat transfer coefficient of a stainless steel block in liquid nitrogen bath based on the temperature acquisition data. Considering the oscillating data and some unsmooth transition points in the inverse-heat-conduction calculation result of the heat-transfer coefficient, a two-step data-fitting procedure was proposed to obtain the expression for the boiling heat transfer coefficients. The coefficient was then verified for accuracy by a comparison between the simulation results using this expression and the verifying experimental results of a stainless steel block. The maximum error with a revised segment fitting is around 6%, which verifies the feasibility of using IHCM to measure the boiling heat transfer coefficient in liquid nitrogen bath.