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1.
本文讨论了互换性定律的族系,研究了非训练行为不准确现象,讨论了行为互换性的需求,推论了行为互换性定律的存在,建立了行为互换性的概念,创建了行为互换性定律的命题及其数学模型,详述了定律的内涵,分析了行为互换性与其他互换性的关系,讨论了行为互换性定律的对象范围、互换类型、自身特点和作用意义,对行为互换性定律进行了验证分析,讨论了行为互换性定律的应用,并给出了应用例子。  相似文献   

2.
《互联网时代》是以全球背景下的视野,聚焦了历史、聚焦了文化、聚焦了社会功能,通过十集的影像表达,缔造了一个时代所呈现的互联网巨大变革,满足了受众,创造了经济效益,开创了中国纪录片史上的又一个里程碑,同时创造了较高的社会现实意义。完成了近乎完美的中国映像,为中国纪录片占有国际地位奠定了社会基础。  相似文献   

3.
简述了模拟水波的原理,使用面向对象方法对水波3D实时模拟系统进行了结构设计,给出了设计模式的结构图,提出了一个可复用的系统框架.详细介绍了使用HLSL对Gerstner水波进行编程的方法,实现了水波实时渲染的模拟并给出了关键的程序代码.最后分析了使用Gerstner波进行水波模拟存在的不足并提出了改进建议.  相似文献   

4.
健康有益的社团活动不仅丰富了校园文化,培养了学生的兴趣爱好,扩大了学生的求知领域,使大学生活丰富多彩,而且对大学生的心理成长具有积极的作用。即社团活动使大学生获得了归属感,丰富了情感体验,提高了交往能力,增强了合作意识,提升了自信心,促进了大学生社会化的进程。  相似文献   

5.
本文论述了研究标准化性质的意义,阐述了4个性质的内涵,分别研究了其理论关系和特点,提出了4个性质的证明方法,并作了相应证明,论述了4个性质的应用关系,给出了部分代表性的应用领域。  相似文献   

6.
王强 《硅谷》2014,(8):115+103-115,103
随着社会的发展,科学技术的进步,计算机技术在各个领域中得到了广泛的应用。计算机技术在会计领域中发挥了重要作用,逐步建立起了会计电算化体系,充分发挥了计算机自动、高效、准确的优势,受到了会计人员的青睐,计算技术在会计领域中的应用提高了会计核算的准确性,提高了会计人员的工作效率,保障了会计工作快速、高效、高质量的完成。文章对会计中计算机技术的应用进行了探讨。  相似文献   

7.
介绍了一种以VBA作为研发平台的千分尺证书记录系统。介绍了系统的结构,并详述了几个关键模块的设计和系统的防错功能,千分尺证书记录系统的研发,减轻了工作量,降低了劳动强度,杜绝了人为产生的偶然性失误,提高了劳动效率。  相似文献   

8.
对盒体零件的冲孔工艺方案进行了分析,介绍了各种冲孔工艺方案的优缺点,从而确定了利用凸轮机构,实现了该零件的径向冲孔。介绍了该模具结构及工作过程,给出了零件的工艺计算方法,提出了模具的设计方法,为解决同类零件的冲孔提供了参考。  相似文献   

9.
本文简述了小壳体零件的特点,提出了以往生产中产品由于壁薄而废品率高的问题,由于零件设计和铸件毛料入手作以具体分析,改进了工艺方法,增加了加工余量,更改了毛料,实践证明,改进后的工艺方法,大幅度降低了加工中的废品率,提高了劳动生产率,满足了该零件的设计要求,为公司节省了大量生产成本。  相似文献   

10.
标准化学科几何互换性定律的创建   总被引:1,自引:1,他引:0  
本文讨论了规律和定律的关系和特点,讨论了几何互换性的本质关系,推论了互换性定律的存在,创建了动配合互换性定律、定位配合互换性定律、紧配合互换性定律,建立了定律的命题、数学模型和关系模型,详述了每个定律的内涵,创建了支持互换性工程应用的几何互换性空间,讨论了互换性定律的应用,创建了广泛适用的互换性空间。  相似文献   

11.
Resonant microelectromechanical systems are promising devices for real time and highly sensitive measurements. The sensitivity of such sensors to additional mass loadings which can be increased thanks to the miniaturisation of devices is of prime importance for biological applications. The miniaturisation of structures passes through a photolithographic process and wet chemical etching. So, this paper presents new results on the anisotropic chemical etching of the gallium arsenide (GaAs) crystal used for this application, in several solutions. This paper focuses on the micro/nanostructuration of the sensing surface to increase the sensor sensitivity. Indeed, this active surface will be biofunctionalized to operate in biological liquid media in view of biomolecules detection. Several experimental conditions of etching bath composition, concentration and temperature were examined to obtain a large variety of geometrical surfaces topographies and roughness. According to the orientation dependence of the chemical etching process, the experiments were also performed on various GaAs crystal plates. The bath 1 H3PO4:9 H2O2:1 H2O appeared to be particularly adapted to the fabrication of the GaAs microstructured membrane: indeed, the bath is highly stable, anisotropic, and, as a function of temperature, it allows the production of a large variety of GaAs surface topographies.  相似文献   

12.
新型智能电化学微加工系统的研究   总被引:8,自引:0,他引:8  
约束刻蚀剂层技术在三维超微图形复制加工的新型技术。本文根据约束刻蚀剂层技术的工艺特点,介绍了约束刻蚀剂层电化学微加工仪器的组成,讨论了具有微力传感的纳米级微定位系统的研究与开发。利用研制 的加工仪器,在半导体GaAs进行刻蚀加工,复制出微孔阵列,其排列周期与模板的微锥阵列的排列周期吻合得很好,同时在铜板上也成功进行了微孔刻蚀加工。  相似文献   

13.
研究了非掺GaAs半绝缘单晶的液封垂直梯度凝固法(VGF)生长技术,解决了Si沾污和C浓度的控制问题,得到了直径2英寸非掺半绝缘低位错单晶。测试表明:该单晶的位错密度较LEC单晶下降近一个数量级,电学参数与LEC单晶类似,接近国个VGF单晶的的参数指标。  相似文献   

14.
Several studies on gas-liquid pipe flows in micro gravity have been performed. They were motivated by the technical problems arising in the design of the thermohydraulic loops for the space applications. Most of the studies were focused on the determination of the flow pattern, wall shear stress, heat transfer and phase fraction and provided many empirical correlations. Unfortunately some basic mechanism are not yet well understood in micro gravity. For example the transition from bubbly to slug flow is well predicted by a critical value of the void fraction depending on an Ohnesorge number, but the criteria of transition cannot take into account the pipe length and the bubble size at the pipe inlet. To improve this criteria, a physical model of bubble coalescence in turbulent flow is used to predict the bubble size evolution along the pipe in micro gravity, but it is still limited to bubble smaller than the pipe diameter and should be extended to larger bubbles to predict the transition to slug flow. Another example concerns the radial distribution of the bubbles in pipe flow, which control the wall heat and momentum transfers. This distribution is very sensitive to gravity. On earth it is mainly controlled by the action of the lift force due to the bubble drift velocity. In micro gravity in absence of bubble drift, the bubbles are dispersed by the turbulence of the liquid and the classical model fails in the prediction of the bubble distribution. The first results of experiments and numerical simulations on isolated bubbles in normal and micro gravity conditions are presented. They should allow in the future improving the modelling of the turbulent bubbly flow in micro gravity but also on earth.  相似文献   

15.
The empirical pseudopotential method coupled with the virtual crystal approximation has been used to compute the electronic band gaps and pseudocharge densities for the compound semiconductor GaAs and the alloy Ga1−xAlxAs. The variation of the compositional fraction of AlAs in GaAs has been correlated to the high pressure effect on GaAs.  相似文献   

16.
Grazing exit X-ray fluorescence (GE-XRF), which has unique advantages in surface and film analysis, is a development of XRF related to total reflection XRF. The combination of polycapillary X-ray optics with total reflection geometry in the detection path allows micro analysis in thin layer characterization. This technique was applied to analyze a series of titanium and iron layers which were deposited on GaAs single crystal by metal vapor vacuum arc ion sources. Thickness and density of the layers result from fitting the experimental data to model calculations, and the information of layer uniformity can be acquired by two-dimensional scan analysis. The GE-XRF method has application for complete layer characterization and process control during the layer deposition.  相似文献   

17.
The objective of this paper is to predict the twin formation in the Gallium Arsenide (GaAs) crystals grown by vertical gradient freeze (VGF) method at different growth parameters. The deformation twins are formed in the GaAs crystal during its growth processes from the melt. The thermal stresses generated by the temperature profile during the crystal growth can be the primary cause of deformation twin formation. Temperature gradients are depend on the geometrical and physical crystal growth parameters, such as crystal diameter and imposed temperature gradients on the surface of the solidifying crystal in VGF. A quantitative thermal stress model is developed here for predicting the twin formation in GaAs grown by VGF at different growth parameters. This investigation is expected to further the understanding of twin formation. This understanding will provide valuable information to crystal growers to study the influence of growth parameters on twin formation for growing low defect GaAs crystal.  相似文献   

18.
Metalorganic vapor phase epitaxy (MOVPE) was used to grow semiconductor structures comprising a GaAs single crystal matrix with incorporated layers of aluminum nanoclusters (Al-NCs). A new regime of GaAs overgrowth on Al-NC layers is proposed, which ensures planarization of the semiconductor layer surface at a thickness comparable with the height of Al-NCs.  相似文献   

19.
A micro pulsating heat pipe made of a thin clear Teflon tube of 1.6 mm ID was used to observe the pulsating flow inside a heat pipe under different gravity levels using parabolic flights. More vigorous pulsating flow was observed under microgravity, compared to the depressed movements under hypergravity. Two metallic micro pulsating heat pipes made of an aluminum plate with small internal channels were also tested to investigate the effect of gravity on their heat transfer characteristics. Reduced gravity experiments were performed aboard Falcon 20 aircraft flying parabolic trajectories. Under normal and hypergravity conditions, both the orientation of the pulsating heat pipe and locations of the heated and cooled sections affected the heat transfer performance. Under reduced gravity, however, the heat pipes showed better operating and heat transfer performance than that under normal and hypergravity. These experiments have for the first time confirmed that pulsating heat pipes are capable of operating under reduced gravity and thus are suitable for deployment in space applications such as satellites.  相似文献   

20.
Potential advantages of using relaxed porous InGaAs/GaAs superlattices as buffer layers are considered. The X-ray diffraction patterns and the photoluminescence spectra of multilayer epitaxial InGaAs/GaAs heterostructures upon electrochemical etching are indicative of a partial relaxation of elastic stresses in the component epilayers. The stress relaxation in porous superlattices, used as buffer layers on both porous GaAs and periodic single crystal heterostructures, provides for a small but still significant positive effect related to a decrease in elastic energy accumulated in the growing structure.  相似文献   

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