推荐信

在国外,上大学需要向学校提供自己的推荐个,有的推荐信由自己写成,有的则由推荐人写出.……     

在学生中实行核心读者制的初步尝试

<正> 去年,我们在学生中实行了核心读者制,深受同学们的欢迎.所谓核心读者,就是一部分思想品质较好,热爱学习,热心图书馆工作,办事认真负责的学生读者.核心读者应履行的义务是每周定日定时到图书馆工作一定时间(暂定     

体育教师非权力性影响力探析

体育教师对学生的影响力有权力性和非权力性之分。结合体育教学实践活动，阐述了教师非权力性影响力的内涵，强调了其在体育教学中的意义；认为体育教师非权力影响力的构成因素包括：品格因素、情感因素、知识因素和才能因素。     

洛克惩罚教育的心理学诠释

惩罚教育是洛克教育思想的组成部分,他在《教育漫话》中对惩罚教育进行了相关的阐述。从心理学的角度诠释洛克对惩罚教育的态度及惩罚教育的方法,挖掘其中所蕴涵的心理学思想,对现今学校的品德教育有一定的启迪意义。     

Microcalorimetry studies of the antimicrobial actions of Aconitum alkaloids

The metabolic activity of organisms can be measured by recording the heat output using microcalorimetry. In this paper, the total alkaloids in the traditional Chinese medicine Radix Aconiti Lateralis were extracted and applied to Escherichia coli and Staphylococcus aureus. The effect of alkaloids on bacteria growth was studied by microcalorimetry. The power-time curves were plotted with a thermal activity monitor (TAM) air isothermal microcalorimeter and parameters such as growth rate constant (μ), peak-time (T_m), inhibitory ratio (I), and enhancement ratio (E) were calculated. The relationships between the concentration of Aconitum alkaloids and μ of E. coli or S. aureus were discussed. The results showed that Aconitum alkaloids had little effect on E. coli and had a potentially inhibitory effect on the growth of S. aureus.     

Optimal linear attitude estimators via geometric analysis

Three optimal linear attitude estimators are proposed for single-point real-time estimation of spacecraft attitude using a geometric approach. The final optimal attitude is represented by modified Rodrigues parameters (MRPs). After introducing incidental right-hand orthogonal coordinates for each pair of measured values, three error vectors are obtained by the use of dot or/and cross products. Corresponding optimality criteria are rigorously quadratic and unconstrained, which do not coincide with Wahba’s constrained criterion. The singularity, which occurs when the principal angle is close to π, can be easily avoided by one proper rotation. Numerical simulations show that the proposed three optimal linear estimators can provide a precision comparable with those complying with the Wahba optimality definition, and have faster computational speed than the famous quaternion estimator (QUEST).     

基于步进电机的流苏丝线绕制机智能控制器的设计

针对流苏丝线绕制过程中对动力机构的控制要求,系统设计以ATMEL89S52系列单片机为核心控制器,采用SANY0步进电机作为动力机,利用东芝公司的TB6560AHQ步进电机细分驱动器和ATMEL公司的I2C总线器件AT4C02芯片对系统掉电时的实时速度、圈数和转向等数据进行保护,实现了丝线绕制过程中对力矩、转向、速度、圈数和捻度等参数的精确控制,减轻了工人的劳动强度,提高了流苏的生产质量和效率.     

国内电子商务信息生态链理论研究分析与对策

近十年来电子商务信息生态链的研究一直是学者们相继研究的热点.论文通过统计和归纳的方法,对国内相关的文献进行分类和总结,试图揭示目前国内电子商务信息生态链理论研究的现状,指出其存在的不足,并提出加强学术交流与合作、定性研究与实证研究相结合以及创建核心研究群从而推动核心影响力这三条改进策略.     

北周宇文廙、宇文广墓志疏证

新出土《周故大将军西阳昭公墓志》与北周庾信撰《周大将军赵公墓志铭》分别记载了宇文廙和宇文广的生平及家族世系.两位志主为北周皇族嫡亲,曾任秦州刺史一职,其家族对北周王室立下过赫赫战功,与陇右秦州有着很深的渊源.据墓志记载,志主宇文廙籍贯为河南洛阳,与北周皇族出身武川不符,通过考证可知,宇文泰通过建立府兵制、改变皇族及士兵的郡望姓氏,广幕关陇贵族,使得北周在和东魏与梁的斗争中脱颖而出.墓志对于宇文廙籍贯的交代,是北周皇族改郡望之历史确据,和北周建国前期种种政治行为相暗合,为我们深入了解北周的历史提供了可贵的资料.两通墓志的记述较《周书》本传更为详尽,具有重要的学术价值.     

偏序半群的偏序同态和商序同态的若干重要性质

通过偏序半群的同余、半格同余和自然序半格同余,对偏序半群的偏序同态与商序同态的性质进行了刻画,得到了一些重要结论.