杆件内力的一种计算方法

为了让学生能够更好的理解各种变形条件下杆件的内力,将杆件截面上的分布内力系向形心简化得到主矢和主矩,主矢和主矩分别沿三个坐标轴分解得到三个分力和三个分力偶矩矢。基于空间任意力系的平衡方程,确定各种变形条件下杆件的内力。教学实践证明,该方法能够较好的帮助学生理解杆件内力的概念,从而提高教学质量和教学效果。     

组织内知识市场有效性的结构与测量

知识是竞争优势的主导性来源,运用市场机制管理知识能够有效地提升组织内知识的效能,这种知识市场的有效性直接决定了组织能否获取知识优势。本文首先采用开放式问卷对107名管理者与员工进行了调查,归纳性分析表明组织内知识市场有效性包括六类影响因素;其次,选取315个样本对组织内知识市场有效性的影响因素进行了实证检验,结果表明组织内知识市场有效性是一个五因素的结构,同时本文设计的量表具有较好的信度和效度。这一理论结构的发现以及相应量表的研制具有重要的理论价值和应用价值。     

Development of a method for automatic basso continuo playing

The purpose of this study is to develop an automatic basso continuo playing system. In order to find a musically appropriate sequence of chords, we propose the principle of “harmony cost”, which is defined as the sum of two different costs: one is the “local cost” which indicates the unlikelihood of a certain chord allocation and the other is the “transition cost”, which indicates the unlikelihood of a certain connection between two chords. Automatic basso continuo playing is realised by searching for the optimal chord sequence, which minimises the accumulated harmony cost. The proposed method is evaluated by three experiments. Each experiment verifies the effectiveness of the proposed method.     

ERW焊管用于油井的试验研究

本文概述了ERW焊管在国内外的应用情况。通过对原材料及生产工艺的试验研究,阐述了用ERW方式生产定尺油管和连续油管用于油井的可行性,同时该方法也是解决国内众多ERW焊管生产设备产能过剩的有益探索。     

A principal stress method of stress analysis

The equations of equilibrium in a stress field as given by Lamé are compared with those given by Cauchy. The (P ? Q and P ? R) terms of the Lamé equations identified by the new words detend and double detend are invariant for any point in a stress field. The principal stresses are defined as real stress components. The $\text{?Xx}\text{?x}$ terms of the Cauchy equations are considered as imaginary force components. Real and imaginary stress and force components are differentiated by the differences between ray vectors, as for example a force which has only one real value and direction, and diffuse vectors, as for example a gradient, which has a real value in any direction. Shear is differentiated from detend value by its variation with the direction in which it is taken. Shear is found to be an imaginary component of force parallel to a plane.The photoelastic equidetend (isochromatic) and isoclinic maps of a plane stress field define, for any point, a gradient triangle with the three maximum gradients, Δ(P ? Q) ΔP and Δ ? Q, for its sides. Five quantities, the detend (P ? Q), the ratio of the detend to its gradient (r₄), the ratio (r₃) of the isoclinic normal ds₃ to the stress axis direction change along its length dα, the direction of the equidetend normal (θ) and the orientation of an isoclinic line (ω) with reference to a principal stress direction, determine each gradient triangle. Five equations which define elements of the gradient triangle in terms of the five measurable quantities, are developed. Definition of the triangle can be complete with two of the five measurable quantities or two of the five equations omitted. Graphic integration of principal stress changes along any line in a stress field can be made by plotting the line straight and measuring the area swept out by the normal projections, along the line, of the sides of the gradient triangle, after it has been rotated through 90 degrees.Properties of the gradient triangle are used to solve several symmetrical stress problems and to integrate along two lines through a stress field.     

A method for the precise measurement of optical path-difference,especially in stressed glass

In connection with an investigation that involved the measurement of optical path-difference and thence birefringence it became necessary to have much higher accuracy than is ordinarily attained. After a careful study of the various methods available it appeared that the one which best meets the requirements of precision and simplicity is a method first elaborated by Friedel (1893), and based on an interesting property possessed by a fixed combination of (1) a polarizer, (2) the birefracting material, and (3) a quarter-wave plate, each placed in a definite orientation to the others. When plane parallel monochromatic light passes through the elements of this fixed combination in the order shown above, the emergent light is plane polarized and the azimuth is related in a simple manner to the path-difference of the specimen. Since this azimuth can be measured by means of an analyzer and graduated circle, the determination of path-difference thus reduces itself to the measurement of an angular displacement, which can be done easily and with high precision.The method was first made applicable to a petrographic microscope for the purpose of determining the path-difference at a given spot in small specimens. Later, there was constructed a separate polarimeter in which large specimens could be conveniently measured. This instrument has given all that was expected of it in facility and rapidity of taking readings, and for any path-difference has a sensitivity about one hundred times greater than that of the devices in common use.A resumé of the general relations for elliptically polarized light as applied to the present method is given, and the magnitude of the errors that may arise is discussed in detail.     

A direct measurement method of quantum relaxation time

The quantum relaxation time of electrons in condensed matters is an important physical property, but its direct measurement has been elusive for a century. Here, we report a breakthrough that allows direct determination of quantum relaxation time at zero and non-zero frequencies using optical measurement. Through dielectric loss function, we connect bound electron effects to the physical parameters of plasma resonance and find an extra term of quantum relaxation time from inelastic scattering between bound electrons and conduction electrons at non-zero frequencies. We demonstrate here that the frequency-dependent inelastic polarization effect of bound electrons is the dominant contribution to quantum relaxation time of conduction electrons at optical frequencies, and the elastic polarization effect of bound electrons also dramatically changes the plasma resonance frequency through effective screening to charge carriers.     

学科硬度测量:FGA方法的应用

本文运用图形面积比例 (FGA)方法 ,对中国学术期刊进行了统计分析 ,并结合问卷调查研究 ,认为此方法不仅可用于一般学科的硬度测量 ,也可用于分支学科的硬度测量。此外 ,应用FGA方法还发现我国的科学发展与世界先进水平具有很大差距。     

国内组织信息化评价方法现状研究

随着信息化建设的不断深入,人们对于信息化的建设也越来越趋于理性,开始思考如何对不同类型的组织进行信息化的评价.经过半个多世纪的发展,国内学者在信息化评价指标体系的建设、评价理论与方法方面已经取得了一定成果,并积累了一定经验.通过查阅文献,对国内组织信息化水平评价方法现状进行了初步的研究,并在分析的基础上作了展望.     

模糊综合评价法在高校内部审计风险评价中的应用

首先分析了应用模糊综合评价法的可行性，然后利用模糊综合评价方法对高校内部审计风险进行评价，并予以实例详细说明，以达到有效控制内部审计风险的目的。     

数字贸易测度的融合比法:从构念到实测

当前,信息通信技术推动国际贸易变革,形成以数字贸易为核心的第四次全球化浪潮.衡量数字贸易规模,对于我国把握宏观经济形势,制订相关政策法规,参与全球规则制定和全球市场竞争具有重大意义.本文基于《中国商务年鉴》利用中国两化融合平台数据测算出各类数字贸易服务子项融合比,进而计算得出我国数字贸易总体规模,借以分析我国数字贸易发展现状和发展趋势,并在此基础上提出四条启示与建议:制定数字贸易发展战略规划,强化数字贸易管理机制;优化数字贸易产业结构,加快发展数字贸易核心产业;加快服务贸易数字化转型,促进服务外包与制造业融合发展;营造良好的数字治理环境,强化组织与制度创新.     

主成分分析法在县域工业科技成果转化绩效评价的运用

主成分分析方法是一种依据客观数据,将多种影响因素综合成少量几个影响因素的方法.运用主成分分析法对构建的县域科技成果转化绩效评价指标体系进行分析,把众多体现科技成果转化效益的因素简化成几个综合成分,并以江苏省52个县域的科技成果转化绩效评价为例,得出了较合理的评估结果,为县市科技成果转化绩效评价提供借鉴.