两双折射平板间的Casimir力

本文在量子表面模式方法的基础上,计算了两平行双折射平板间的Casimir力,两平板的光轴平行于平板平面,平板间为真空区域。在延迟条件下,给出了两平板间Casimir力的近似解析表达式。     

Leibniz流形上Casimir函数

通过研究微分同胚及Leibniz映射对Leibniz流形上Casimir函数的作用,得出了：（1）Leibniz流形（M,[.,.]M）上的Casimir函数C（x）,可以由微分同胚φ：M→N诱导为N上的Casimir函数（φ-1）＊C;（2）可逆的Leibniz映射ψ：M→N,可以把N上的Casimir函数的线性组合sum （λiCi） from i=1 to s拉回为M上的Casimir函数.最后给出了Leibniz向量场和Casimir函数间的几个公式.     

边界条件下的电磁场的正则量子化

利用Fadecv-Jakiw方法对带边界条件的电磁场进行量子化,将场变量的傅里叶展开的模作为新的动力学变量获得对易关系,所有的量子化过程都在经典解空间进行。计算了两无穷平行平面边界的Casimir能。     

对经济法与民商法关系的方法论透视

本文基于对方法论是一门学科的基础和标志的认识，从方法论的角度对经济法与民商法的关系问题进行了探讨。这是一种全新的探讨，首次提出经济法的方法论是整体主义与和谐辩证法，而民商法的方法论是个体主义与冲突辩证法。因此两大法律部门的根本差异是基于这两种不同思维方法产生的。在此基础上对两种方法论的关系及两大法律部门对社会关系的调整做了辩证解释。     

当事人申请再审程序限制性要件的解释

《最高人民法院关于适用<中华人民共和国民事诉讼法>的解释》第383条确立了当事人申请再审一次原则。规定中"当事人"存在"再审申请一方当事人"以及"双方当事人"两种不同的解释方法;"再审判决、裁定"存在"一审再审的上诉案件的再审"以及"一审发回重审上诉后的再审"两种形式上并非直接表现为再审裁判的情况。再审申请程序不同于再审程序,其严肃性应当适当让位于当事人的程序参与权,因此可以采用"申请人不同"以及"再审适事由不同"的双重要件模式来解释当事人的范围。基于再审程序的纠错性和严肃性,"再审判决、裁定"应当包含不同解释下可能衍生出的两种情况,即当事人不能对一审再审的上诉案件和一审发回重审的上诉案件提起再审申请,以此强调再审程序的纠错功能,避免目前司法实践中存在的再审不终的问题。     

乡愁·邮票·关联

台湾诗人余光中的《乡愁》是人教版初中语文讲读课文。《乡愁》中的名句＂乡愁是一枚小小的邮票＂历来解释不一。归纳起来,各家解释主要分两种观点：一种认为这是一个比喻句;一种认为这里采用了象征的手法。我们认为这两     

“显示”理论：一个新的解释思路

“显示”理论是维特根斯坦为解决划界问题而提出的一种语言分析思想,它在维特根斯坦《逻辑哲学论》中占有重要地位。学界对这种思想进行了不同的解释,从总体上看,主要有三种观点：一是对“显示”理论进行分类;二是对“显示”理论进行宗教解释;三是类型论的解释。在分析了这三种观点的基础上,我们认为这三种解释都存在一定的问题,因此,我们提出了一个基于“显示”理论的新的解释思路。     

你是我的英雄

字典里对英雄的解释有两种:一是为群众谋利益而有功绩的人,一是旧指英武过人的人。我对英雄的解释也有两种:一是为人民为国家浴血奋战的人,另一种最后说。一个热闹的午后,我溜进了黑黢黢的电影院看《天地英雄》,看到了两个英雄,一个叫来     

基于.NET 2.0的RSS阅读器的设计与实现

RSS阅读器是指从网页获取RSS Feeds并解释和显示摘要信息的工具..NET提供了读取和解释XML文件的类库,.NET应用程序,一种是基于Windows Form的Windows Client形式,另一种是基于ASP.NET的Web Form形式.为了简化程序设计中的一些细节,突出RSS阅读器的核心技术,文章采用Windows Form实现RSS阅读器.     

外语学习本质再认识及其对外语教学的启示

本文从知识学习观的角度来考察外语学习本质特征,并以此为据分析解释了外语学习中常见的两种现象,最后讨论了本结论对基于内容的外语教学实践的启示。     

超导体中的双体模型

在戈德（Gorter．C．J）和卡西米尔（Casimir．H．B．G）的二流体模型的基础上，建立了适合于高温超导体的新模型──双体模型，通过论证，双体模型是合理的．     

Snippets of physics

The vacuum state of the electromagnetic field is far from trivial. Amongst other things it can exert forces that are measurable in the lab, in a curious phenomenon known as Casimir effect. T Padmanabhan works at IUCAA, Pune and is interested in all areas of theoretical physics, especially those which have something to do with gravity.     

A special fermionic generalization of lineal gravity

INTRODUCTION The models of lineal gravity (the gravity theory in (1 1)-dimensions) are Liouville theory (Jackiw, 1985), a simplest non-trivial theory based on the sca- lar curvature R and additional scalar field, and so-called ‘string-inspired’ model (Cangemi and Jackiw, 1992; 1993), where scalar (dilaton) field arises from the string theory. Both models can also be obtained by dimensional reduction from (2 1)-di- mensions (Achúcarro, 1993; Cangemi, 1992; Grig- nani and Nardelli, 19…     

Mathematically based and practically based explanations in the elementary school: teachers’ preferences

This article focuses on elementary school teachers’ preferences for mathematically based (MB) and practically based (PB) explanations. Using the context of even and odd numbers, it explores the types of explanations teachers generate on their own as well as the types of explanations they prefer after reviewing various explanations. It also investigates the basis for these preferences. Results show that teacher-generated explanations include more MB explanations than PB explanations. However, many still choose to use mostly PB explanations in their classrooms, believing that these explanations will be most convincing to their students. The implications for teacher education are discussed.     

Preschool Children's Explanations of Plant Growth and Rain Formation: A Comparative Analysis

This paper explores the different types and characteristics of preschool children's explanations of plant growth and rain formation. The children's explanations were categorized as naturalistic, non-naturalistic, or synthetic, i.e., explanations containing both naturalistic and non-naturalistic parts. In regards to plant growth the children tended to rely on synthetic or on naturalistic explanations, which involved direct and indirect agents (such as water, a person, fertilizers, roots) enabling the plant to grow. Non-naturalistic explanations of plant growth, or the non-naturalistic parts of synthetic explanations, were mainly animistic (anthropomorphic). In the case of rain formation the children most frequently used non-naturalistic explanations, which were mainly teleological or metaphysical. The naturalistic explanations recorded on rain formation, as well as the naturalistic parts of synthetic explanations tended to have a non-agentive character, i.e., children considered rainwater as preexisting in containers such as the clouds. Overall, the explanations recorded about plant growth tended to be more complex than the ones for rain formation. It is suggested that science activities designed for preschool children should take into account the types and characteristics of their explanations in order to select which phenomena are appropriate for this age group, and aim at fostering the children's ability at formulating naturalistic explanations.     

To teach or not to teach the conceptual structure of mathematics? Teachers undervalue the potential of Principle-Oriented explanations

Principle-oriented explanations have demonstrated to foster students’ mathematical understanding, as they integrate conceptual and procedural information to make the solution process tangible to novice students. Teachers, however, often omit conceptual information when explaining procedures. In two experimental studies, we tested the hypothesis that teachers’ tendency to omit conceptual information may have occurred, as teachers generally devalued the potential of principle-oriented explanations. In Study 1, we randomly provided two cohorts of secondary students (N = 129) with principle-oriented versus procedure-oriented explanations on four mathematical topics. Afterwards, students answered a knowledge test. We replicated previous findings that students with principle-oriented explanations outperformed students with procedure-oriented explanations on the knowledge test (application test, transfer test). In Study 2, we gave mathematics teachers (N = 69) these explanations as judgment materials. Teachers randomly rated a balanced set of four explanations of Study 1 which varied in their procedure- versus principle-orientation. We found no significant differences between teachers’ judgments of principle- versus procedure-oriented explanations. Content analyses of the justifications revealed that teachers were more concerned about students’ overload when judging principle-oriented explanations than procedure-oriented explanations. Our findings replicated the beneficial effects of principle-oriented explanations for novice students’ understanding. Furthermore, they highlight the need to sensitize teachers for potential effects of providing principle-oriented explanations.     

Why Instructional Explanations Often Do Not Work: A Framework for Understanding the Effectiveness of Instructional Explanations

Although explanations are a common means of instruction, research shows that they often do not contribute to learning. To unravel the factors giving rise to the ineffectiveness of instructional explanations, we propose a framework that brings together empirical work on instructional explanations from a variety of research fields, including classroom instruction, tutoring, cooperative learning, cognitive skill acquisition, learning from texts, computer-supported learning, and multimedia learning. In our framework, we identify the distinctive characteristics of instructional explanations, present general guidelines for designing instructional explanations, and describe factors influencing both the generation and use of instructional explanations. It is argued that future research should uncover in more detail the interrelations between the different aspects of providing and using instructional explanations and their specific effects on learning.