直螺线管对称轴上的磁场     

王福谦 《长治学院学报》2003,20(5):26-28

文章以矩形螺线管轴线上的磁场分布特点为基础 ,将螺线管的对称截面按矩形进行分割 ,分析得出螺线管对称轴上磁场分布的一般规律。  相似文献   

论刚体对坐标轴转动惯量的平移和旋转变换     

于志明 《洛阳师范学院学报》2007,26(5):50-52

本文导出了刚体对坐标轴的转动惯量的平移和旋转变换一般式。  相似文献   

Navigating the discursive tensions of the public university: the case of a South African student     

Kate le Roux 《Teaching in Higher Education》2019,24(2):231-247

As public universities seek to be locally responsive and compete internationally, tensions arise between expansion and equity, and between discourses of neoliberalism and social justice. This article focuses on how students navigate these tensions, and the implications for how they can act, interact and be. Norman Fairclough’s three-level view of the social and language, and his method of critical discourse analysis are used to analyse longitudinal interviews with an undergraduate science student. This student is, on account of his home and schooling, considered ‘historically marginalised’ at an historically-white, English-medium South African university. The results show how the student navigates multiple positionings that draw on notions of class, language, independence, progress, choice, care, and so on. It is argued that while universities should support students to navigate some of these tensions, there is a need to re-imagine structuring discourses related to the ‘normal’, ‘independent’ university student.  相似文献   

纵向数据线性混合模型中M估计的渐近正态性     

孙慧慧 《周口师范学院学报》2011,28(5)

对纵向数据的线性混合模型yk=Xkβ＋Ckτk＋ek用Fisher得分迭代法得到了参数的M估计（稳健估计）,并在一系列的正则条件下,证明了参数M估计的渐近性质．  相似文献   

轴控制器在大型流动演出中的应用--以庆祝澳门回归祖国20周年文艺晚会为例     

侯鹏强  唐伟  向飞 《演艺科技》2020,(1):1-4,23

介绍轴控制器在庆祝澳门回归祖国20周年文艺晚会中的应用,对应用中的关键技术和难点进行分析和说明。  相似文献   

Application of the Levenshtein Distance Metric for the Construction of Longitudinal Data Files     

Harold C. Doran  Paul B. Van Wamelen 《Educational Measurement》2010,29(2):13-23

The analysis of longitudinal data in education is becoming more prevalent given the nature of testing systems constructed for No Child Left Behind Act (NCLB). However, constructing the longitudinal data files remains a significant challenge. Students move into new schools, but in many cases the unique identifiers (ID) that should remain constant for each student change. As a result, different students frequently share the same ID, and merging records for an ID that is erroneously assigned to different students clearly becomes problematic. In small data sets, quality assurance of the merge can proceed through human reviews of the data to ensure all merged records are properly joined. However, in data sets with hundreds of thousands of cases, quality assurance via human review is impossible. While the record linkage literature has many applications in other disciplines, the educational measurement literature lacks details of formal protocols that can be used for quality assurance procedures for longitudinal data files. This article presents an empirical quality assurance procedure that may be used to verify the integrity of the merges performed for longitudinal analysis. We also discuss possible extensions that would permit merges to occur even when unique identifiers are not available.  相似文献   

大型集装箱船的总纵强度实用计算方法     

吴善刚  邱文昌 《上海海事大学学报》1998,(3)

以我国１９９６年《钢质海船入级与建造规范》对大型集装箱船的总纵强度的要求为标准,讨论了具体装载状态下船舶总纵强度的校核方法,并着重探讨了在资料不完整的情况下与总纵强度校核有关的船舶资料的计算制作方法。  相似文献   

立轴磨床多轴加工进刀轨迹优化控制模型     

杨晓雪 《科技通报》2015,(6)

对立轴磨床多轴加工进刀轨迹优化控制模型的设计,提高模型的加工精度,为评价数控立轴磨床多轴联动的误差补偿提供依据。传统的进刀轨迹优化控制模型采用稳态预测误差控制的控制算法,导致磨床进刀的交叉耦合轨迹预补偿误差较大。提出一种基于直线轨迹的轮廓误差补偿的立轴磨床多轴加工进刀轨迹优化控制模型。以CAD为预处理软件工具,对加工模具进行空间曲线生成实体模型,构建三维造型,进行立轴磨床的多轴加工进刀轨迹控制模型设计,正确地选择加工刀具,合理地设置切削参数,构建刀具进刀的时间控制轴。构建复杂的零件加工控制系统解耦得到两个独立的控制子系统,实现进刀轨迹三轴联动控制,构建立轴磨床多轴加工进刀轨迹控制系统的轮廓误差向量最小化目标函数,实现控制模型改进。仿真结果表明,该模型能有效提高加工精度,减小误差。  相似文献   

难美项群空中身体翻转动作类型与构架研究     

缑小燕 《北京体育大学学报》2015,38(5):108-114

摘要：鉴于当前世界竞技体育项目的高速发展,为了更好的适应新形势变化,针对表现难美性项群中自由体操、单跳、蹦床、跳水和空中技巧五个项目中,身体动作的主因子“空中身体翻转动作”进行分析研究,目的是通过该研究,能够对项目间的相互借鉴、以及项目技术的相互支撑起到一定的帮助作用,并对项目的发展具有一定的实际意义。文章通过文献资料法、访谈法、录像分析法等科学研究方法进行系统分析,得到以下结论：1）空中身体翻转动作是运动员身体在空中围绕运动轴完成单向或多向翻腾和转动的技术动作,是五个表现难美性项目的核心技术。2）依时间的递进进行观察和描述,一个完整的身体翻转动作包含起动加速、起跳、空中翻转、落停4个相互连接的技术环节。3）自由体操和单跳的空中身体翻转动作常以多式样的空中身体翻腾转体难度动作直接连接另一个空中身体翻转难度动作。4）空中身体翻转技术动作的递进式发展历程可分为五个发展阶段：单一翻腾阶段;单一的翻腾或旋转阶段;复合翻转阶段;多翻多转及“叠加”翻转阶段和自由体操与单跳进入突出平面挂串连接阶段。5）发展表现难美性项群空中身体翻转动作的对策设计为：及时研究、积极适应国际评分规则的变化,科学把握空中身体翻转动作的有序性发展规律, 主动发掘空中身体翻转技术动作的创新途径。  相似文献   

Fostering Social and Emotional Skills for Well-Being and Social Progress     

Koji Miyamoto  Maria C. Huerta  Katarzyna Kubacka 《European Journal of Education》2015,50(2):147-159

Children need a balanced set of cognitive, social and emotional capabilities to adapt to today's demanding, changing and unpredictable world. OECD countries and partner economies recognise the importance on the holistic development of individuals. However, there are big gaps between stakeholders' knowledge, expectations and practices on how to foster such skills. This paper presents evidence on the importance of social and emotional skills; on how policy makers and schools are currently enhancing and monitoring such skills; and, on the existing gaps between knowledge, expectations and practices to mobilise these skills. The paper concludes by pointing ways in which education stakeholders can do more to better develop and mobilise the skills that drive individual's well-being and social progress. The paper draws on findings and frameworks that are being published in a full OECD report entitled ‘Skills for Social Progress: the Power of Social and Emotional Skills’ in the first half of 2015.  相似文献