浅析立体照片的拍摄原理及观看方法

本文介绍了立体照片的合成原理，以及用普通照相机拍摄立体照片和观看立体照片的方法     

Si1-xGex/Si异质结构中热应力对临界厚度的影响

系统分析了Si_1-xGe_x/Si外延生长中热应力对外延生长的影响．假设Si Ge的线膨胀系数是随Ge的组分线性变化的，由此计算出热应变和应变能密度．根据能量平衡原理，当失配应变能密度加热应变能密度等于位错能密度时，外延层达到临界厚度，在People的基础上得出了改进的临界厚度计算公式．理论计算值与People的实验值更相近． 关键词：     

动态热不敏感谐振腔分析

发展了热不敏感谐振腔的辅助参量处理方法,给出了可适用于任何多元件谐振腔新的严格的解析解法,详细分析了谐振腔的稳定性以及输出模式与功率的热稳特性。同时还引入了热敏感程度的概念,并进而求得了最佳热不敏感条件:g₁g₂=1/2,μ₁=0。 关键词：     

直接标度分析动力生长

用直接标度分析方法研究了分子束外延生长和在长程时间、空间关联条件下的动力生长过程。分别得到了在强、弱耦合区的粗糙指数和动力学指数,并对其结果进行了讨论,说明了其弱耦合的结果与动力重整化群的结果一致的原因。 关键词：     

吸附式制冷的动态特性分析

以非平衡吸附模型为基础,计算了加热流体温度变化时,系统的性能系数COP以及单位质量吸附剂制冷功率SCP随时间的变化,结果表明加热流体温度变化对系统COP和SCP值有很大影响,并且影响相对滞后于加热流体温度的变化.计算结果也表明对于两吸附床的吸附式制冷系统,在稳定运行时,由于吸附床温度、吸附量不断变化、循环周期较长及封闭期影响,其瞬时性能也是不稳定的,如果采用三床交替循环,则可有效改善其瞬时性能的稳定性.     

动态接触角的初步分析

应用经典的Moffatt解,通过引入接触线特征参数λ给出接触线上的粘性剪切应力,导出动态接触角和接触线移动速度的关系,尝试解释文献中两种不同测量方法所得静态接触角不一致的现象,理论所揭示的动态接触角和接触线移动速度的关系曲线和以往文献中的曲线形式基本一致,通过和Hoffman试验数据的比较发现,λ与流体性质无关,是表征固壁性质的特征参数,并初步探讨了λ的数理意义。     

ANALYSIS OF A PIEZOELECTRIC MULTIMORPH IN EXTENSIONAL AND FLEXURAL MOTIONS

Impedance and admittance matrices are presented for the analysis of the beam-type piezoelectric multimorph (PM). Each piezoelectric layer is polarized in the thickness direction. The stacking sequence can be arbitrary, and both the extensional and flexural motions are considered. The variational principle is used for deriving the lumped conjugate parameters: two mechanical ports for the extensional motion, four mechanical ports for the flexural motion, and m electrical ports for the m piezoelectric layers. The resonance and antiresonance frequencies are then easily calculated from the admittance matrices. For the case of all the piezoelectric layers either in series or parallel connection, them +6 ports reduce to the seven ports, and its impedance and admittance matrices are presented. The present methods are applied to the cantilevered PM and their electromechanical behavior is studied. The tip trajectory of the cantilevered piezomotor is also investigated using the presented matrices. It is found that the present methods are very effective in analyzing the multilayer piezoelectric transducers.     

考虑质量效应的混合态中的vortex物质的Brownian运动

本文对包含质量效应的ｖｏｒｔｅｘ体系的动态特性进行了研究通过使用ＭＣＦＭ和Ｋｒａｍｅｒｅｓｅｓｃａｐｅ ｒａｔｅ方法，对包含钉扎作用的ｖｏｒｔｉｃｅｓ体系的 ｃｒｅｅｐ行为进行了研究发现在考虑了质量效应之后，ｖｏｔｔｉｃｅｓ体系的ｃｒｅｅｐ与通常的过阻尼状态下的结果很接近在没有使用任何钉扎势对外加电流的特殊依赖的情况下得到了非线性电流电压特性曲线．并且发现，ｖｏｒｔｉｃｅｓｃｒｅｅｐ的有效势垒高度随外加驱动力的非线性变化．同时发现随ｖｏｒｔｅｘ质量的增加，相应的ｃｒｅｅｐ速率减小．收稿日期：１９９…     

回旋行波管动力学分析及数值计算

 以小回旋电子注、均匀截面光滑壁圆柱波导为例,对回旋行波管动力学色散方程作了解析分析和讨论;数值计算和分析了注波互作用耦合系数与电子注参数的相互关系,为优化选择电子注参数,提高注波互作用效率获得了依据。     

ANALYSIS OF THE FLEXURAL VIBRATION OF A THIN-PLATE BOX USING A COMBINATION OF FINITE ELEMENT ANALYSIS AND ANALYTICAL IMPEDANCES

Many practical built-up thin-plate structures, e.g., a modern car body, are essentially assemblies of numerous thin plates joined at their edges. The plates are so thin that they invariably support the weight of the structure and machinery using their substantial in-plane stiffness. Consequently, vibrational power injected into the structure from sources mounted at these stiff points is controlled by high impedance long-wavelength in-plane waves in the plates. As the long in-plane waves propagate around the structure, they impinge upon the numerous structural joints at which short-wavelength flexural waves are generated in adjoining plates. These flexural waves have much lower impedance than the in-plane waves. Hence, the vibration of thin-plate structures excited at their stiff points develops into a mixture of long in-plane waves and short flexural waves. In a previous paper by the same authors, a numerically efficient finite element analysis which accommodated only the long in-plane waves was used to predict the forced response of a six-sided thin-plate box at the stiff points. This paper takes that finite element analysis and, drawing on theory developed in two additional papers by the same authors, couples analytical impedances to it in order to represent the short flexural waves generated at the structural joints. The parameters needed to define these analytical impedances are identified. The vibration of the impedances are used to calculate estimates of the mean-square flexural vibration of the box sides which compare modestly with laboratory measurements. The method should have merit in predicting the vibration of built-up thin-plate structures in the so-called “mid-frequency” region where the modal density of the long waves is too low to allow confident application of statistical energy analysis, yet the modal density of the short flexural waves is too high to allow efficient finite element analysis.     

ITERATIVE SEMICLASSICAL SOLUTIONS OF CIP GIANT MAGNETORESISTANCE IN MAGNETIC MULTILAYERS WITH MIXED LAYERS TAKEN INTO ACCOUNT

The problem of solving semiclassically the current in-plane (CIP) giant magnetoresistance in magnetic multilayers with mixed layers taken into account is comprehensively studied. The solution of this problem is attributed to the solution of G-coefficients. A new choice of local spin quantization-axes is adopted so that the number of G-coefficients is reduced from Johnson-Camley's 4(5n+1) to our 4(4n+1). Furthermore, we show that actually only a half number of G-coefficients need be sloved for the symmetric structure and a superlattice can be simplified to a symmetric penta-layered structure. The main result of this paper is the establishment of the iteration method for solving the G-coefficients. Associating this method with that of numerical integration, for which a formulism is developed, the GMR. can be conveniently calculated.     

用快速傅氏变换作次声信号的动态谱分析

本文提出了应用小型数字计算机和快速傅氏变换作次声信号动态频谱的分析方法, 实验证明这种方法行之有效, 且容易实施, 从而克服了模拟分析器难以克服的困难. 本文介绍数字化频谱分析的一般原理, 着重讨论记录在纸上的次声信号的采样和分析方面的有关问题, 给出了用F O R T R A N 语言编写的动态谱分析计算程序和绘图程序, 和一个实际例子的分析结果. 关键词：     

用快速傅氏变换作次声信号的动态谱分析

本文提出了应用小型数字计算机和快速傅氏变换作次声信号动态频谱的分析方法,实验证明这种方法行之有效,且容易实施,从而克服了模拟分析器难以克服的困难。本文介绍数字化频谱分析的一般原理,着重讨论记录在纸上的次声信号的采样和分析方面的有关问题,给出了用FORTRAN语言编写的动态谱分析计算程序和绘图程序,和一个实际例子的分析结果。     

动力系统的时间序列重构分析

利用延迟重构变换的雅可比行列式,分析了常微方程系统重构的拓扑性质.指出重构的嵌入性质除与重构维数有关之外,还依赖于延迟时间的选择,依赖于重构变量本身的条件稳定性质,利用条件Lyapunov指数分析了重构变量本身对重构的影响。提出了从时间序列计算雅可比行列式的方法,并以R?ssler系统为例进行了讨论。 关键词：     

DYNAMIC ANALYSIS OF A SPIRAL BEVEL-GEARED ROTOR-BEARING SYSTEM

Spiral bevel gears can transmit motion between two rotors, which are commonly perpendicular to each other. In this paper, the dynamic analysis of a spiral bevel-geared rotor-bearing system is studied. Firstly, the constraint equation describing the relationship between the generalized displacements of spiral bevel gear pairs is derived briefly. Then the modelling of coupled axial-lateral-torsional vibration of the rotor system geared by spiral bevel gears is discussed. Finally, the mechanism of coupled vibration of the spiral bevel-geared rotor system is analyzed theoretically and the dynamic behavior of the system is investigated numerically. The conclusions are characterized as follows. The influences of the critical speeds in rigid journal supports, stability threshold speed and unbalanced responses in hydrodynamic journal bearings are not remarkable in comparison with the spur bevel-geared system under the same conditions. However, the critical speeds and stability threshold speed are essentially affected by boundary conditions such as the torsional stiffness, and meanwhile the effect of the unbalanced responses is not prominent under the concerned rotating speeds except that around the resonance peaks. The steady state response due to torsional excitation is also analyzed, and the results show that it cannot be neglected either in the torsional direction or in the lateral and axial directions in the spiral bevel-geared rotor system.     

水平轴风力机结构动力学分析

本文以水平轴风力机为研究对象,基于动量-叶素理论和广义坐标系下的多自由度拉格朗日方程,利用模态分析方法建立了风轮、机舱和塔架耦合系统的运动方程,并用FORTRAN语言编制仿真程序.对风力机Turbowinds T600-48的固有频率和动态响应特性进行计算,并与实验数据对比分析,初步结果表明该程序的有效性.     

房间空调系统动态特性的分析

本文建立了房间空调系统的动态模型及其末端空气处理单元的各个模型.模型精确地预测了在外界气候条件改变和送风参数变化了的情况下的送风温度、冷冻水流量、冷冻水出水温度、房间温度和相对湿度.整个过程采用闭环控制,冷冻水流量和蒸汽量作为两个被控参数.为了抑制震荡,模糊参数经过了仔细的调试.模拟结果表明,相对于传统的PID控制,基于模糊自适应PI控制的系统能够在更短的时间内有效地抑制扰动,并凡偏差更小.     

氩孤钎焊加热区比热流分布的动态分析

通过对不同弧长、不同电流氩弧的高速摄影拍摄以及利用影片数据分析处理系统对其动态过程的研究,发现用高斯函数模拟氩弧钎焊加热区的比热流q(r)分布特性时,理论计算值与测量值符合得较好.实验结果表明,氩弧钎焊时采用大电流的焊接规范既不经济亦无必要.因为,由q(r)分布模型可知,当弧长不变增加焊接电流时,氩弧钎焊加热区半径变小,而q_m急剧增大,往往诱发液态钎料过热,毛细填充作用不强等问题,使钎焊质量下降;当焊接电流不变增加弧长时,加热区半径显着增大,q_m减小,反而有利于保证氩弧钎焊质量和生产效率.     

光折变各向异性自衍射动态特性的严格耦合波分析

利用严格耦合波衍射理论分析光折变相位光栅各向异性自衍射的动态特性,并以Ce:KNSBN晶体进行了实验验证.