步进电机细分驱动系统设计

为了提高步进电机的运行精度,消除或减小振动现象,文章基于细分驱动技术,以单片机ATmega128为核心,应用恒流斩波PWM发生电路和H桥功率驱动电路设计了步进电机的驱动系统。系统控制参数通过上位机设定,以串口通信传给单片机。实验结果表明：电机运行平稳,振动噪音小,转矩大,精度高,系统具有良好的应用前景。     

Semiparametric Estimation of a Change-point for Recurrent Events Data

One particular recurrent events data scenario involves patients experiencing events according to a common intensity rate, and then a treatment may be applied. The treatment might be effective for a limited amount of time, so that the intensity rate would be expected to change abruptly when the effect of the treatment wears out. In particular, we allow models for the intensity rate, post-treatment, to be at first decreasing and then change to increasing (and vice versa). Two estimators of the location of this change are proposed.     

重大公共卫生事件背景下的青年思想政治教育工作

新冠疫情的暴发作为一场全球性重大公共卫生事件对青年思想状况产生了较大影响。思想政治教育必须回应青年的思想关切,并给予及时的引导。基于重大公共卫生事件做好思想政治教育工作有五个基本着力点,即：以树立正确的灾难观为着力点,培养危机意识和担当精神;以倡导科学应对疫情为着力点,提高理性思辨能力和自我防护能力;以讲好中国抗疫经验为着力点,增强四个意识,坚定四个自信;以反思人与自然关系为着力点,增强自然保护意识和生态文明理念;以关注全球抗疫大局为着力点,筑牢人类命运共同体意识。     

一场声势浩大的新闻事件策划——浅析《金沙》的推广宣传策略

“新闻事件策划”这个命题自上世纪九十年代中期被提出以后,长期受到广泛争议和关注。在笔者的研究中,以一系列新闻事件策划的理论和实践研究成果为评判标准,主要关注成都市历时打造一年的文化名片“金沙”,以及作为媒体聚焦点的《金沙》音乐剧。在分析“金沙”成功的造势背后,揭示这条“金光闪闪”的文化产业链运作的新思路。     

对手机媒体的传播学思考

手机媒体是一种继报纸、广播、电视、网络四大媒体之后出现的、以手机为载体的媒体,手机媒体传播的特点是即时的大众传播和人际传播的结合,我们可以称之为"人际大众传播"。本文认为,作为"跨媒体"时代信息传播的重要成员,手机媒体对大众传播的广泛参与,优化了传播过程,弥补了以往大众传播的缺陷,同时也打破了主流媒体原有的传播思路与格局,对主流媒体产生了极大的影响。     

Consistent Estimation of the Structural Distribution Function

Motivated by problems in linguistics we consider a multinomial random vector for which the number of cells N is not much smaller than the sum of the cell frequencies, i.e. the sample size n . The distribution function of the uniform distribution on the set of all cell probabilities multiplied by N is called the structural distribution function of the cell probabilities. Conditions are given that guarantee that the structural distribution function can be estimated consistently as n increases indefinitely although n / N does not. The natural estimator is inconsistent and we prove consistency of essentially two alternative estimators.     

Semiparametric regression of clustered current status data

This paper discusses regression analysis of clustered current status data under semiparametric additive hazards models. In particular, we consider the situation when cluster sizes can be informative about correlated failure times from the same cluster. To address the problem, we present estimating equation-based estimation procedures and establish asymptotic properties of the resulting estimates. Finite sample performance of the proposed method is assessed through an extensive simulation study, which indicates the procedure works well. The method is applied to a motivating data set from a lung tumorigenicity study.     

新型城镇化进程中河北省城乡社区医疗卫生配套研究

新型城镇化建设的稳步推进及卫生体制改革的逐步深化,为河北省推进城乡社区医疗卫生发展改革带来了重大机遇,但河北省城乡社区医疗卫生配套状况仍然面临着重视不够、高水平人员短缺等问题。为此,应进一步加大城乡社区医疗卫生配套的宣传力度、建立并完善城乡社区高层次人才的制度机制、积极借鉴国外社区医疗卫生先进经验,以实现河北省城乡社区医疗卫生的可持续发展。     

Arenas of comfort and conflict: peer relationship events and young people's educational attainment

Previous research suggests that developments in young people's peer relationships may either compound or alleviate the adverse impacts of other major life changes during adolescence. We explored this proposition with respect to young people's educational attainment upon leaving high school, using longitudinal data from a large cohort of Australian secondary school students (n?=?1612) who have taken part in the Our Lives research study between the ages of 12/13 and 19/20 years. Our analysis focused on the role of peer relationship events such bullying, friendship problems, falling in love, and breaking up with someone. Bullying and romantic involvement were associated with lower odds of receiving a competitive tertiary entrance rank at the end of high school. However, close, resilient friendships – in which status and identity conflicts may be more easily tolerated and resolved – may help to offset the role of these other events. As well as reviewing the consequences of our findings for young people's educational and occupational trajectories in the longer-term, we highlight their implications for future research and policy in this area.     

我国高校学分制实施现状与改革策略研究

学分制又称学分积累制,它是以学分作为计量学生学习分量单位,以学生取得必要的基本学分作为毕业标准的一种教学管理制度。我国是推行学分制较早的国家之一,现有的学分制模式有完全学分制模式和不完全学分制模式两种。目前,在学分制实施中还存在着学分制内在要求与现行课程体系的矛盾;学生选课需求的广泛性与学校提供选修课范围相对狭窄的矛盾;学分制实施条件要求与教育教学资源不足的矛盾;教师专业的单一性和学生需求多样性的矛盾;学分制目标管理与传统的教学管理之间的矛盾等。论文针对上述问题提出了相应的改革策略。