共查询到20条相似文献，搜索用时 120 毫秒
1.
本文研究了应用UG软件对"点云"数据进行曲面重构的过程:扫描线的生成、扫描线的排序、曲面裁剪和曲面的拼接直至曲面的构成,提出了一种先平面裁剪后拼接融合的多个小平面拼接方法,可使多个曲面光滑地连接成为一体。 相似文献
2.
研究了滑板运动和冲浪运动中动力学模型的特性,即在光滑圆滚线上和粗糙圆滚线上的滑板,在竖直平面内,同一水平线上经过一个最低点的 任意两点所有光滑连接线中;物体无初速度滑动时,所需时间最短的曲线是圆滚线（最速降线）这一特性对目前国际上滑板运动和冲浪运动具有指导性的意义。 相似文献
3.
王珍娥 《雁北师范学院学报》2007,(4)
若一元函数存在导数,则可推得函数在某点连续,曲线呈光滑状态.而对多元函数来说,自变量在平面区域、空间区域甚至n维空间区域内变化,导数概念相对复杂.本文就导数概念的推广略加探讨. 相似文献
4.
黄国基 《湖南城市学院学报》1999,(6)
研究了滑板运动和冲浪运动中动力学模型的特性,即在光滑四滚线上和粉植圆滚线上的滑板,在竖直平面内,同一水平线上经过一个最低点的任意两点所有光滑连接线中;物体无初速度滑动时,所需时间最短的曲线是圆滚线（最速降线）这一特性对目前国际上滑板运动和冲浪运动具有指导性的意义． 相似文献
5.
用最优化理论提出一种新的薄膜结构裁剪方法，并用Ｂ样条曲线对裁剪图边界进行光滑处理，提高了裁剪分析的精度．最后给出了一个张拉式薄膜结构裁剪分析实例． 相似文献
6.
王珍娥 《雁北师范学院学报》2007,23(1):75-76,87
若一元函数存在导数，则可推得函数在某点连续，曲线呈光滑状态．而对多元函数来说，自变量在平面区域、空间区域甚至n维空间区域内变化，导数概念相对复杂．本文就导数概念的推广略加探讨． 相似文献
7.
本文通过对一般平面测设中的常用算法分析,设计出能够对坐标点、导线、曲线、任意支点进行综合计算的多用途便携式PC运行程序。该程序通过简单的算法设计,达到了针对任意变化的置镜点、后视点、放样点交互进行复杂平面测设的要求。 相似文献
8.
本文通过对一般平面测设中的常用算法分析,设计出能够对坐标点、导线、曲线、任意支点进行综合计算的多用途便携式PC运行程序.该程序通过简单的算法设计,达到了针对任意变化的置镜点、后视点、放样点交互进行复杂平面测设的要求. 相似文献
9.
10.
江家敏 《开封教育学院学报》1990,(3)
与一元函数的广义积分定义类似,重积分概念也可以推广,从而得到区域无界和函数无界两种广义重积分。它们在概率论和其它学科有广泛的应用,但这个问题一般数学分析教科书中却极少涉及,为此,本文以广义二重积分为例,对广义重积分的问题作一些探讨。 定义一 设D是平面上无界区域(如全平面、半平面、角域或有界区域外部等),f(x,y)在D上有定义;用任意光滑曲线r在D中划出有限区域σ,f(x,y)((x,y) 相似文献
11.
The experiment in which a candle is burned inside an inverted vessel partially immersed in water has a history of more than
2,200 years, but even nowadays it is common that students and teachers relate the change in volume of the enclosed air to
its oxygen content. Contrary to what many people think, Lavoisier concluded that any change in volume in this experiment is
negligible; moreover, the explanation relating oxygen consumption in the air with its change in volume is known to be wrong.
In this work we briefly review the history behind the candle experiment and its relationship with some typical erroneous explanations.
One of the key factors behind Lavoisier’s success was the use of experiments carefully designed to test different hypotheses.
Following these steps, we performed several closed volume experiments where the candle wick was replaced by a capillary stainless
steel cylinder supported and heated by a nichrome filament connected to an external power supply. Our recorded experiments
are displayed as web pages, designed with the purpose that the reader can easily visualize and analyze modern versions of
Lavoisier’s experiments. These experiments clearly show an initial phase of complete combustion, followed by a phase of incomplete
combustion with elemental carbon or soot rising to the top of the vessel, and a final phase where the hot artificial wick
only evaporates a white steam of wax that cannot ignite because no oxygen is left in the closed atmosphere. After either a
complete or incomplete combustion of the oxygen, our experiments show that the final gas volume is nearly equal to the initial
air volume. 相似文献
12.
张红旗 《廊坊师范学院学报》2010,(3):80-83
公推直选乡镇长与乡镇党委书记出现的时间、发展现状与趋势、制度依据、选举成本,以及乡镇长与乡镇党委书记在乡镇政权中的作用有明显的不同。在我们看来,直接选举乡镇党委书记,发展的空间更广阔,对乡镇民主建设与乡镇政府职能转型所起的作用更大。 相似文献
13.
The concept of metacognition refers to one’s knowledge and control of one’s own cognitive system. However, despite being widely
used, this concept is confusing because of several reasons. First, sometimes it is not at all clear what is cognitive and
what is metacognitive. Second, researchers often use the same term, namely, “metacognition” even when they refer to very different
aspects of this complex concept. Alternatively, researchers may use different terms to indicate the same metacognitive elements.
Another foggy matter is the interrelationships among the various components of metacognition discussed in the literature.
This conceptual confusion regarding the concept of metacognition and its sub-components calls for in-depth theoretical and
conceptual clarifications. The goal of this article is to portray a detailed example of a conceptual analysis of meta-strategic
knowledge (MSK) which is one specific component of metacognition. This specific example is used to draw a general model for
conceptual analyses of additional metacognitive components. The approach suggested here is to begin with a clear definition
of the target sub component of metacognition, followed by a systematic examination of this sub component according to several
dimensions that are relevant to metacognition in general and to that sub component in particular. The examination should include
an analysis of how the details of the definition of the target sub-component refer to: (a) general theoretical metacognitive
issues raised by prominent scholars; (b) definitions formulated and issues raised by other researchers who have investigated
the same (or a similar) sub-component and, (c) empirical findings pertaining to that sub-component. Finally, it should be
noted that since metacognition is a relational rather than a definite concept it is important to situate the context within
which the conceptual analysis takes place. 相似文献
14.
The term professional vision points to the many nuanced ways professionals see. This paper traces the development of a professional vision of a researcher and a teacher looking at classroom practices. The researcher’s interest was to capture and study notable aspects of the teacher’s practice. Through a coding scheme, disparate classroom events were organized and analyzed to yield a researcher’s professional vision of the teacher’s practices. For the teacher, through reviewing the video records of his own classroom practices, his professional vision provided a basis for him to reflect and develop professionally. Leveraging on the work of the researcher, he initiated and transformed his own practices. Their collaboration yielded a mutually informed development of professional vision of classroom practices. In juxtaposing the two developments, the researcher and the teacher’s views can be contrasted, their distinctive interests highlighted and common grounds explored. Some implications for developing professional vision are drawn, and it is in the common grounds of the teacher’s professional development and seeing with a goal of enhancing of student learning that hold some promise of a mutual interest in developing a professional vision of classroom practices. 相似文献
15.
影响物流中心选址的因素及一种选址方法 总被引：2，自引：0，他引：2
文章论述了影响物流中心选址的七大因素,建议采用模糊评判的方法,该方法克服了传统选址方法的片面性、局限性和计算的复杂性,可对多种可供选择的方案做出明确的排序,使选址问题变得更加合理、科学与全面,更加反映客观实际. 相似文献
16.
This article reports on a case study where a professional musician was assigned to a primary school as mentor in a project where 14 primary-aged children, with their teacher's direction, were involved in the composition of a piece of music that would act as prologue to the school's major production. The researchers were interested in aspects of the composition project that appeared to develop student's compositional skills and motivation and how the mentor might exercise his role in the composition project alongside the teacher, who was the school's music specialist. A range of data was analyzed: classroom observations, emails, questionnaires, and one-on-one and focus-group interviews. Findings suggested that the involvement of the mentor was well received by the pupils and that the mentor and teacher complemented one another in their enactment of both pedagogical and compositional roles. Students enjoyed a high sense of success in the production of their composition. Student learning were highly variable and a range of activities and processes was identified by students as contributing to their learning. 相似文献
17.
王前新 《荆门职业技术学院学报》2009,24(4):88-93
地方本科院校学报具有学术窗口、学院名片、学人摇篮、服务平台等功能。对地方本科院校学报进行科学的定位,首先要结合学校定位,其次要着眼地域定位,寻求错位发展,尤其要处理好学术性与应用性的关系、内向性与开放性的关系、科学性与人文性的关系。为提高学报的办刊水平与质量,办出特色,地方本科院校学报要坚持走特色化与品牌化道路,在办刊质量、学术品位、特色栏目创设、编辑素质、装帧设计上下功夫。 相似文献
18.
This article has no direct link with academics, children, students or those who teach: I severed almost all such connections several years ago. It describes the rewards and challenges of leading a reminiscence group of elderly people, all of whom suffer some level of memory loss and/or severe physical disability; most are wheelchair-bound. It contains examples of their autobiographical talk which I recorded separately from group meetings and transcribed, exclusively for the satisfaction of each individual concerned. Ours is not a society which cherishes its aged members. What becomes of their identity? Who are they now? They are, of course, people – as interesting as those in our classrooms. They too need to know their own worth. 相似文献
19.
M. L. Carrió Pastor 《European Journal of Engineering Education》2007,32(5):599-612
Second language acquisition is a hard task for teachers, since to achieve the motivation from students to practice a language simulating a real context is very difficult. On the one hand, students are often influenced by their mother tongue and more when they are practising a second language with a partner from the same nationality. On the other, technology is part of our lives and teachers should use all the tools in order to motivate students to learn any topic. So, if we integrate technology in the methodology we use when teaching a second language and students can practise with international partners, the results can be surprising. Chats, scanning texts, games, filling forms, etc. are just some of the activities our students can do in order to improve their command of a second language and also these activities can be used by content teachers in order to complement content learning. In the present paper, we provide some examples of activities designed by collaborating with content teachers based on websites, and then we analyse the effect they produced on students. We contrast the methodology used to propose tasks based on websites and those based on texts, and finally, evaluate their effect on the motivation of students. 相似文献
20.
Exemplifying definitions: a case of a square 总被引：1，自引：1，他引：0
In this study we utilize the notion of learner-generated examples, suggesting that examples generated by students mirror their
understanding of particular mathematical concepts. In particular, we explore examples generated by a group of prospective
secondary school teachers for a definition of a square. Our framework for analysis includes the categories of accessibility
and correctness, richness, and generality. Results shed light on participants’ understanding of what a mathematical definition
should entail and, moreover, contrast their pedagogical preferences with mathematical considerations. 相似文献