北京志愿者协会之发展道路研究

本文首先对北京志愿者协会进行了概要介绍,接着对协会的优势劣势进行了解析,最后对于北京志愿者协会的发展道路进行了思考,指出北京志愿者协会可以和其他营利组织合作“创收”、实现协的独立和自主性、发展一种志愿服务的文化范围、形成有效的志愿者服务的激励机制。     

Genetic analysis of fruit shape traits at different maturation stages in sponge gourd

The fruit shape is important quantitative trait closely related to the fruit quality. However, the genetic model of fruit shapes has not been proposed. Therefore, in the present study, analysis of genetic effects for fruit shape traits （fruit length and fruit perimeter） in sponge gourd was conducted by employing a developmental genetic model including fruit direct effects and maternal effects. Analysis approaches of unconditional and conditional variances were applied to evaluate the genetic behavior of fruit shape traits at economical and physiological maturation times. The results of variance analysis indicated that fruit length and fruit perimeter were simultaneously affected by fruit direct genetic effects and maternal effects. Fruit direct genetic effects were relatively more important for fruit shape traits at whole developmental period. The gene expression was most active at the economical maturation stage （1-12 d after flowering） for two shape traits, and the activation of gene was mostly due to direct dominance effects at physiological maturation stage （13-60 datter flowering）. The coefficients due to different genetic effects, as well as the phenotypic correlation coefficients, varied significantly between fruit shape traits themselves at various maturation stages. The results showed that it was relatively easy to improve fruit shape traits for industrial purpose by carefully selecting the parents at economical maturation stage instead of that at physiological maturation stage.     

模态试验分析在教学中的应用和实践

模态试验分析是了解结构动态特性的有效手段.通过模态试验,可以计算出结构的固有频率、模态振型、阻尼比等参数,为结构设计与优化打下坚实的基础.在实验教学中,通过对模态试验的基本原理、主要步骤和试验中注意事项的介绍和分析,可以指导学生完成模态实验,加深学生对理论知识的理解和掌握,提高学生的动手能力、独立思考能力和分析解决问题的能力.     

生物化学综合性实验的探索与评价

以河北科技师范学院2005级生物科学、生物技术专业学生为样本,通过对生物化学综合性实验效果的调查,说明综合性实验在突出学生主体地位、激发学生兴趣等方面起到了积极的作用,能够在培养学生团队合作精神、科研能力等多方面综合能力的提升。     

扩招背景下提高实践教学质量的方法研究与实践

探讨了扩招背景下工程训练实践教学面临的机遇和挑战,对工程训练中提高教学质量的方法和途径进行了研究,提出了通过构建工程训练体系、实践教学保障体系和考核评价体系提高实践教学质量的思路,并结合整个教学团队的工作实践,阐述了在实践教学中的应用情况.     

一个代数不等式的再研究

《数学通报》2004年第4期刊登的1485号问题是：设xk〉0,k=1,2…n,p∈R,q〉0,且令∑k=1^n xk=s,Sk = pxk ＋ q（ s - xk）,     

氧气和二氧化碳在血液中的运输方式

本文论述了氧气和二氧化碳在血液中的运输方式。     

高校创业教育的本质与逻辑

高校创业教育是指在高校中实施的、旨在培养学生现在或未来开拓事业所需素质的一种教育活动,其本质是培养人。高校创业教育的有效开展,必须要以现实的人为逻辑起点,以发展的人为逻辑终点,而要实现从起点到终点的转变,则需要在高校整个人才培养的体系框架内,不断强化对学生开拓性素质的培养。     

《中国音韵学研究》讹夺举例

《中国音韵学研究》是研究汉语言文字学的重要经典著作之一,它的出版标志着现代音韵学的诞生。但古音字类表存在的一些讹夺等现象尚未引起前修时贤的关注。现参照《康熙字典》、《广韵》等辞书,分类列举古音字类表的疏漏现象,并以声母表和韵母表中韵字对应的情况稍加说明。     

Replication,pathogenicity, and transmission of SARS-CoV-2 in minks

Minks are raised in many countries and have transmitted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans. However, the biologic properties of SARS-CoV-2 in minks are largely unknown. Here, we investigated and found that SARS-CoV-2 replicates efficiently in both the upper and lower respiratory tracts, and transmits efficiently in minks via respiratory droplets; pulmonary lesions caused by SARS-CoV-2 in minks are similar to those seen in humans with COVID-19. We further found that a spike protein-based subunit vaccine largely prevented SARS-CoV-2 replication and lung damage caused by SARS-CoV-2 infection in minks. Our study indicates that minks are a useful animal model for evaluating the efficacy of drugs or vaccines against COVID-19 and that vaccination is a potential strategy to prevent minks from transmitting SARS-CoV-2.