共查询到20条相似文献，搜索用时 189 毫秒
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讨论了平行光斜入射光栅时的衍射现象和光谱特性，得到了平行光斜入射时的光栅方程、主极大级次的变化规律和对光栅的分辨本领和角分辨率的影响．并计算了斜入射角对光栅测波长实验结果的影响，对所得的结论进行了实验验证，其结果和分析结论完全符合。 相似文献
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首先,从薄透镜的像方焦距公式出发,讨论空间介质折射率的变化对各种结构的凸透镜和凹透镜光学传输特性的影响,得出了会聚透镜和发散透镜对折射率的具体要求,特别是当透镜两侧折射率不同时,情况将变得复杂。其次,证明了凸透镜二次成像的条件,并进行了相关的讨论。 相似文献
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将薄透镜分为六种基本模型,即凸透镜、平凸透镜、凸平透镜、凹透镜、平凹透镜、凹平透镜。推导出六种薄透镜的物方和象方焦距公式。本文研究了薄透镜成像规律和作图的基本方法。研究表明,在介质折射率大于透镜折射率时,凸透镜、平凸透镜、凸平对光都是发散作用,凹透镜、平凹透镜、凹平透镜对光都是会聚作用。各种透镜的焦距与折射球面的曲率半径成正比,曲率半径越小焦距越小,凸透镜、平凸透镜、凸平透镜对光发散作用越强,凹透镜、平凹透镜、凹平透镜会聚作用也越强;当凹面和凸面曲率半径大小相等时,平凸(凹)、凸(凹)平透镜焦距相等且为凸(凹)透镜的二倍。 相似文献
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光纤光栅是一种光无源器件,它是在光纤中形成折射率周期性变化的相位型光栅.由于光纤光栅的光谱特性由其光波导结构决定,因此光纤光栅对温度、应力等环境变量的敏感是其固有特性.光纤光栅传感器不仅具有光纤传感的几乎全部优点,而且还具有可复用性、可同时多参量传感等优点,因此近十年来已迅速成为最重要的光学传感器之一.光纤经过拉锥处理后,由于直径更细,对应力等环境因素变得更加的敏感,因此,基于拉锥光纤的这一特点可以制作高灵敏度的专用传感器.本文介绍了一种利用结合一个经过拉锥处理的多模光纤光栅和一个普通光纤光栅实现温度和应力的同步传感方案. 相似文献
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傅里叶光学是近年来的光学中一个迅速发展的新学科,他是以傅里叶变换为工具,以阿贝成像原理为理论基础,本文提出了一种基于空间频率的的倍频方法。首先使用黑白光栅做空间滤波实验,得到频率越高的次波得到的图样越细锐的结论;其次由于光的色散规律引入闪耀光栅,通过设定闪耀角使衍射零级和干涉零级分开,让高级次的次波能够得到足够的能量,在像平面上得到清晰的图像;最后使用软件模拟特定闪耀角的闪耀光栅,进行模拟实验,验证预期的结果。 相似文献
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对影响醋纤滤棒硬度的因素进行了试验分析:滤棒的硬度随丝束填充量、增塑剂施加量及丝束单丝旦数和总旦数的增加而增加;此外,滤棒的存放时间及存放环境对其硬度亦有不同程度的影响。 相似文献
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Louis Weinberg 《Journal of The Franklin Institute》1951,252(1):43-62
A simple method has been demonstrated for obtaining some solutions of the principal equations of mathematical physics. Tables of solutions have been included in the Appendix so that problems in field theory can be solved with a minimum of labor. 相似文献
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Laura A. Wojcik 《Journal of The Franklin Institute》2003,340(1):63-76
The dynamic effects of muscle strength, timing of muscle activations, and body geometry have been modeled for a wide variety of human activities. These types of models require the development of complex system equations that account for the effects of rigid-body dynamics, musculotendon actuators, passive and active resistance to motion, and other physiological structures. One way in which model refinement can be expedited is through the use of bond graph modeling techniques. While bond graph techniques have been used extensively in a broad variety of applications, they have been used only sparingly in the field of biomechanics, despite the potential suitability of a modular, multidomain approach to the modeling of musculoskeletal function. In the current paper, bond graph modules representing muscle function and rigid-body motions of underlying bone structures are introduced. The system equations generated with the use of these models are equivalent to those developed with more traditional techniques, but the modules can be more easily used in conjunction with control models of neuromuscular function for the simulation of overall dynamic motor performance. 相似文献
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In this paper, a model describing the castor three-dimensional dynamic behavior, is presented. A procedure, based on the Udwadia-Kalaba formulation has been implemented to write the castor non-linear motion equations. The model takes into account the flexural and lateral compliance of the castor frame and the phenomena related to the wheel rotation. To prescind from the wheel-road interaction parameters, the hypothesis of no sideslip of the wheel has been adopted but other tire models can be easily implemented. The non-linear system stability is evaluated integrating the motion equations and performing a fitting procedure on the natural steering oscillation. 相似文献
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This paper concerns the following topics: dependence of shape and size of a static meniscus sitting like a drop on the controllable part of pressure difference across the free surface; stability of static menisci; procedure for creation of a stable static meniscus, appropriate for the growth of a rod with constant radius; temperature gradients and crystallization front displacement; equation for crystal dimension change rate; evolution of crystal radius and of the level of crystallization front; and control of cross-section during growth. This kind of problems appears in semiconductor single-crystal rod growth from a melt by edge-defined film-fed growth (EFG) technique. The novel case where the upper radius of the meniscus is larger than the shaper radius and the meniscus is sitting like a drop is analyzed. For some of the topics numerical illustrations are given. The obtained results can be useful in experiment planning and technology design of single-crystal rod growth by the EFG method. With this aim this study was undertaken. 相似文献
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用方程解决问题,是思维方式的重要转折。小学生初学方程解决问题,情感上不认同,不愿积极主动运用方程;由于改变了已有的思维习惯,出现较大的认知障碍;缺少步骤方法的指导训练,解决问题时,或急于列方程或存在随意性,降低了正确率,无法体现方程思想的优越性。通过介绍方程的产生及其作用,帮助学生转变态度,主动学习运用;让学生在解决问题的过程中,经历、体验、试误,掌握用方程解决问题的步骤方法;通过设元、找等式等专项训练,提高用方程解决问题的能力。 相似文献
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非线性科学已经被广泛应用于数学、物理、化学、经济等领域。许多非线性现象都可以用非线性偏微分方程来很好地描述,所以得到非线性偏微分方程的解具有重要的意义。在研究非线性科学的同时,出现了一些带有扰动项的非线性偏微分方程。为了研究这种扰动偏微分方程,一些以对称理论为基础的扰动方法相继产生。本文主要研究对称扰动理论在偏微分方程中的应用,寻求偏微分方程的近似对称约化和无穷级数解。 相似文献
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The difficulties in solving Fredholm integral equations of the first kind are well known. A classical method has been to convert the equation into a set of m linear algebraic equations in n unknowns (m?n). For computational convenience, it is customary to force m = n and solve the resulting ill-conditioned system using one technique or other. In the general case, a feasible solution, if it exists, can be found by determining the generalized inverse of the coefficient matrix. One method of finding the generalized inverse is to reformulate the problem and observe the steady state response of a system of ordinary differential equations with prescribed initial conditions. Results obtained from this reformulation are found to be comparable in quality to those obtained earlier by other methods. Analog and digital computer implementations are discussed. 相似文献
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章德海 《中国科学院研究生院学报》2000,(2)
通过定义平移算子和差分算子 ,并利用Lax配对的方法 ,找到了KP差分 -微分方程组的正确形式 .定义了差分指数函数 .借助穿衣算子法 ,得到了KP差分 -微分方程组的精确解析解 .还讨论了KP差分 -微分方程组及其解的展开形式 . 相似文献
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蔡玉川 《科技成果管理与研究》2010,(2):73-75
本文应用一组产量和流压数据,通过最小二乘法回归得到二项式产能公式中的系数A和B绘制气井流入动态曲线。该曲线能较直观地反映气井产量和井底流压之问的关系,也反映了气体从气藏流入井底的动态,同时也能分析气井的生产制度是否合理。根据气水在井筒中的流动规律,确定气井携液临界流量及临界流速,从而可以确定油管的直径、下入深度等参数,以便对有杆泵排水采气进行优化设计。根据气井的流入动态、气水两相流动、有杆泵的优化设计,用数学手段精确地描述各个系统的参数动态规律,建立各种数学模型,编制计算机程序进行计算。 相似文献