工程图样中尺寸标注的探讨

在绘制和阅读工程图样时,尺寸标注是一个非常重要且不易掌握的环节.详细论述了标注尺寸的基本规则及标注时的具体要求,并通过具体实例详细论述了标注尺寸的方法和步骤,以及标注尺寸时应注意的事项.     

分布式电源对辐射状电网的电压影响性分析

随着电网智能化的发展,小容量的清洁分布式电源给电网带来的影响逐渐增大.对含分布式电源的等腰负荷模型进行电压影响性建模仿真,得出分布式电源并网位置及容量对电网电压的影响,并提出了考虑DG影响的配网电压控制原则.     

Operational,not theoretical: A critique of the current paradigm in development communication

It has been more than 20 years since Everett Rogers first outlined the elements of the ‘new’, ‘Another Development’, ‘plurality’ paradigm of development. This paradigm was later radicalized and extended by Jan Servaes, who called it ‘multiplicity’. While the paradigm was developed in response to the shortcomings of the earlier modernization paradigm, policy makers in Third World countries continue to use the recommendations of the older paradigm.

This paper suggests that the failure of the new paradigm to replace the older one may be due to its own contradictions and inconsistencies. The paper presents the various elements of this paradigm and then critically evaluates them. It discusses why the conceptualizations in the new paradigm are not always useful, and notes that while some of the voices being used in it may be new, the ideas are really quite old. The overall purpose of the paper is to initiate a systematic critique of the new paradigm—a task the authors feel is long neglected.     

20世纪30年代中国生物学发展方向的一场争论及其文化根源

20世纪30年代,一场看似关于中国生物学发展方向的争论．表面上呈现出不同专业对经费资源的争夺,而当人们考查论战双方主要人物的成长过程、求学经历和社会关系后,很容易发现,这背后其实隐藏着“五四”之后新、旧文化之间的碰撞,以及两种西方哲学思想对国人的深刻影响。     

Prevalence and correlates of meeting the muscle-strengthening exercise recommendations among Chinese children and adolescents: Results from 2019 Physical Activity and Fitness in China—The Youth Study

PurposeThis study aimed to describe the national prevalence of Chinese children and adolescents who met the World Health Organization muscle-strengthening exercise (MSE) recommendations and identify correlates of meeting the MSE recommendations.MethodsCross-sectional data from the 2019 Physical Activity and Fitness in China—The Youth Study, a nationally representative sample of Chinese children and adolescents (n = 80,413; mean age = 13.7 years; 53.9% girls) and their parents, were analyzed. Children and adolescents who reported engaging ≥3 days (up to 7 days) of MSE per week were classified as meeting the MSE recommendations. MSE, demographics, lifestyle behaviors (sport participation, moderate-to-vigorous physical activity, screen time, and sleep duration), exercise intention, peer and parental support, and parental MSE participation were assessed through self-reports. Logistic regression models were used to determine the correlates of meeting the MSE recommendations. The analyses were completed in 2020.ResultsOverall, 39.3% of children and adolescents met the MSE recommendations. Girls, 10th–12th graders, minorities, those from lower income households and those from families with lower parental education were less likely to meet the MSE recommendations. Children and adolescents who were proficient in ≥2 sports were more likely to meet the MSE recommendations (adjusted odds ratio (aOR) = 1.44, 95% confidence interval (95%CI): 1.26–1.65), as were those with more moderate-to-vigorous physical activity (aOR = 1.57, 95%CI: 1.53–1.61). Additionally, children and adolescents with high exercise intention (aOR = 1.60, 95%CI: 1.51–1.69), those whose parents met the adult MSE recommendations (aOR = 1.46, 95%CI: 1.40–1.52), and those who received high peer (aOR = 1.27, 95%CI: 1.20–1.34) and parental support (aOR = 1.07, 95%CI: 1.04–1.12) were more likely to meet the MSE recommendations.ConclusionLess than two-fifths of Chinese children and adolescents met the World Health Organization MSE recommendations. The correlates identified in our study can help inform the development of school and community based strategies and policies to enhance participation in MSE and improve muscular fitness of all Chinese children and adolescents.     

学校道德教育面临的新问题

本论述学校道德教育的目的，阐述在社会主义市场经济体制下学校道德教育面临的新情况、新问题，并提出学校道德教育的方法在新形势下应实现的三个方面的转变。     

我国高考命题的范式和范式转换研究

命题研究是高考改革的重点,范式是研究命题的根本问题。自新中国成立以来,高考命题先后出现了三次命题范式和两次范式转换。首先是政治立意范式向知识立意范式的转换,随后是知识立意向能力立意范式的转换。能力立意范式已经成为高考命题的主流范式,它为高考命题工作带来了革命性的变化,对高考改革具有重要意义。在新的改革时期,命题范式正在发生变化,素质立意范式已经建立。     

关于科技期刊分级目录的思考

随着破除"唯论文""SCI至上"的逐步推进,科技期刊分级目录的探索和应用也在不断变化.对不同类型的科技期刊分级分区进行溯源分析,从优秀期刊和资助期刊评比、影响因子和核心期刊认定,到期刊分区与分级目录,科技期刊被划分成层次鲜明的期刊等级.科技期刊的分区分级在进行期刊评价的同时,也带来了不可忽视的问题:科技期刊"三六九"等分,无法形成共同发展的良好行业生态;"内卷"严重,助长以刊评文的不良学术风气;科技论文和科研经费外流严重,造成版权割让.我们认为:改善科技期刊发展生态,需要发挥学会学术引领作用,以期刊质量为发展着力点;推进出版社科技期刊集约化发展,实现规模化经营;优化政府扶持办法,营造公平市场环境;建立期刊预警和论文撤稿机制,强化科研诚信监控;探索代表作评价制度,破除以刊评文错误导向.     

Health shocks and children's school attainments in rural China

Using a long panel dataset of Chinese farm households covering the period of 1987–2002, this paper studies how major health shocks happening to household adults affect children's school attainments. We find that primary school-age children are the most vulnerable to health shocks, with their chances to enter middle school dropping by 9.9 percentage points when a prime-age adult in their families has a major illness. Our robustness regressions that try to take care of the composition bias in illness reports find larger effects with the upper bound being 16.1 percentage points. We also find that the effects of health shocks vary by gender and birth order. However, middle school-age children are not affected by family health shocks.