有耗非线性介质中的二阶谐波和三波耦合

本文分析了均匀各向同性有耗非线性介质中的二阶谐波和三波耦合问题，等阻尼和相位匹配的条件下导出了耦合波的解析解。     

有耗非线性介质中的二阶谐波和三波耦合

本文分析了均匀各向同性有耗非线性介质中的二阶谐波和三波耦合问题;在等阻尼和相位匹配的条件下导出了耦合波的解析解。     

各向同性手征媒质均匀填充手征波导中的耦合波方程

本文从麦氏方程组和手征媒质的本构关系出发，运用耦合波理论，对各向同性手征媒质均匀填充的手征波导中存在的耦合孪生模式的电场和磁场矢量进行了推导并得到耦合波方程组的一般表达式，同时指出了在弱耦合近似条件下，应用微扰原理求解耦合波方程组的一般思路，为从耦合波的观点来分析手征波导中的各种不连续问题提供了一条新的理论途径。     

外腔式双波长喇曼激光器的耦合波理论

为了对基于喇曼晶体的主要喇曼频移模和次级喇曼频移模的外腔式双波长喇曼激光器进行理论分析，采用光场的波动方程和喇曼晶体中振动波的阻尼谐振子波方程推导出了描述基频光、喇曼光1和喇曼光2的耦合波方程组，通过引入归一化参量对耦合波方程组进行了归一化，并数值分析了输出镜反射率和归一化参量对外腔式双波长喇曼激光器性能的影响。结果表明，选择对主要频移模反射率小于0.5且对次级频移模反射率大于0.5的输出镜、两个喇曼振动模的增益系数相差不大的喇曼晶体，适当提高入射基频光的脉冲宽度可以提高次级喇曼频移模的转化效率，可实现有效双波长运转。所提出的归一化耦合波理论可以作为分析外腔式双波长喇曼激光器的辅助工具。     

反激光的理论分析

对反激光进行了理论分析,内容包括由Doppler效应引起的频移与加宽、离子朗道阻尼布里渊三波耦合、布里渊旁散及宽带激发等各方面的问题.     

PPT光纤波片耦合模方程的解析解

理论分析了PPT光纤波片耦合模方程，得出了一定条件下的解析解，将该解析解和渐进近似结果进行了比较，它们在实际应用的PPT光纤波片中具有很好的一致性。     

平面型有界等离子体的不稳定性

激光与平面型等离子体相互作用,会出现各类非线性过程。本文从等离子体中两个波耦合方程出发,研究了均匀等离子体的不稳定性。当存在阻尼时,就有可能出现不稳定性。而当阻尼很小可被忽略后,将仅出现空间增益效应。对于密度按线性变化的非均匀等离子体,本文得到它的解析解,并讨论了出现不稳定性的条件。     

阻尼相干态与波包量子干涉

本文参照相干态定义和含阻尼及无规力万方程定义了阻尼相干态，并应用于计算波包间的量子干涉。在一般情况下，对于一个含阻尼的系统，波包间产生的干涉条纺将很快消失而很难观察到，但当真空场被压缩时，就清楚地显示出波包间的量子干涉效应。     

Reggia—Spencer移相器相移机理研究

用非简并耦合波方程研究了Reggia-Spencer移相器的工作机理，其结果指出；在非同步耦合条件下，移相器的相移随着耦合因子Q的减小而增强；移相器中传播的本征模式是右旋，左旋椭圆极大波，它不随传统方向或磁化方向而变。     

阻尼相干态与波包量子干涉

本文参照相干态定义和合阻尼及无规力的朗之万方程定义了阻尼相干态，并应用于计算波包间的量子干涉。在一般情况下，对于一个合阻尼的系统，波包间产生的于涉条纹将很快消失而很难观察到，但当真空场被压缩时，就清楚地显示出波包间的量子干涉效应。     

Approximate Boundary Conditions for Thin Structures

In wave propagation problems thin structures are often replaced by boundaries of zero thickness, in order to reduce the numerical mesh. The reduction of thickness has to be incorporated in the approximate boundary condition applied to the interface. This paper presents a modification of an approximate boundary condition originally introduced by Mitzner. The modified Mitzner condition can be applied to the boundary of zero thickness and it is more general and accurate than the commonly used impedance boundary condition. For frequency domain solvers the condition is as easy to implement as the impedance boundary condition. It is tested and compared to the impedance boundary condition for planar and cylindrical structures. The new condition is exact at normal incidence on a planar structure.      

DRES: Data recovery for condition monitoring to enhance system reliability

The system reliability depends heavily on the sensed condition data which are mainly collected by various types of sensors. The missing or faulty condition data can result in wrong decision-making or lead to system fault. To realize data integrity for system condition monitoring, one data-driven framework for recovering condition data is proposed in this article. The proposed model is combined by mutual information and Multivariable Linear Regression (MLR). The correlations among condition monitoring data sets are firstly analysed by mutual information. Then, MLR is utilized to recover condition monitoring data. A case study of aircraft engine condition monitoring data sets which are offered by National Aeronautics and Space Administration Ames Research Center is carried out to evaluate the performance of the data-driven framework.     

Digital and analog hybrid control in adaptive interference cancellation system

The digital proportion control is introduced to improve the performance of the analog adaptive interference cancellation system (ICS). For the high frequency parts of the signals after multiplier are not required, the sampling frequency need not satisfy the sampling theorem for high frequency. Because the sampling, calculation and output expend time in digital control, the ideal condition, delay condition and delay-wait condition are taken into account. Through analyzing the system model with three conditions, we gain the stable conditions of the system, the optimization step factors that can make the system converge fastest and the formulas of the interference cancellation ratios (ICRs). One step convergence can be accomplished under ideal condition, whereas the system can not converge in one step under delay condition and delay-wait condition. The calculation results show the convergence speed of delay-wait condition is slower than that of delay condition. The ICR is improved with the increase of the step factor which is in stable bound, but the convergence speed is decreased if the step factor exceeds the optimization step factor. In order to avoid that confine, the method of amending the steady state weight to improve the ICR is proposed. The analyses are in agreement with the computer simulations.     

精确阻抗边界条件的推导

针对Ｌｅｏｎｔｏｖｉｃｈ阻抗边界条件ＩＢＣ是近似阻抗边界条件这一不足之处，本文利用电磁场理论中的一般边界条件和麦克斯韦方程，考虑到平面波的传播特点，导出了不含近似的精确阻抗边界条件（ＥＩＢＣ），给出了精确阻抗这界条件一般矢量表达式及其在直角坐标系和柱坐标系中的表达形式。导出的结果显示，Ｌｏｎｔｏｖｉｃｈ阻抗边界条件只是精确阻抗边界条件一个特例。     

Condition assessment for automatic tool changer based on sparsity-enabled signal decomposition method

Automatic tool changer (ATC) is one of the key basic parts in CNC machining centers, and the globoidal indexing cam and the groove cam are the functional units for tool changing. Thus the condition monitoring is important for highly efficient and precision machining. In this paper, a condition monitoring system is constructed for the ATC, especially for the globoidal indexing cam, including vibration signal acquisition, fault feature extraction and localization, and condition assessment. In the constructed system, sparsity-enabled signal decomposition method is introduced to extract transient component and reduce noises in the complex vibration signals, and the transient component is always a key feature for fault localization. Simulation study shows that the sparsity-enabled signal decomposition method is effective in transient feature extraction. The experimental application in condition assessment for the ATC demonstrates that the constructed condition monitoring system has the potential to assess the working condition of the ATC in practical application.     

运动薄壳体上电磁场平均边界条件

考虑到采用电磁场精确边界条件处理电磁屏蔽问题的复杂性,为简化电磁屏蔽边值问题的分析及计算,本文利用局部平面波近似法,导出了运动薄导体壳上电磁场的平均边界条件,计算结果表明用该边界条件完全可以取代电磁场的精确边界条件.     

被动微波/红外成像复合导引头交班条件与交班误差研究

针对采用被动微波/红外成像复合导引头的舰空导弹在复合导引交班时,存在交班条件以及交班误差问题,对复合导引头所涉及到的交班问题进行了分类,分析归纳出不同情况下的交班条件,给出交班条件判断方法,提出交班过程的数学模型描写,得出交班条件的实质.在此基础之上求解并计算出基于比例导引的交班误差,并对交班误差的影响因素进行了仿真分析.最后得出舰空导弹在拦截反舰导弹时,在反舰导弹巡航段进行拦截并交班时,交班误差最小,最有利于交班.     

也谈一阶电路的能量陷阱

根据文献[1]提出的能量陷阱的概念，并通过分析一阶电路的能量特性，对存在能量陷阱的根本原因、充要条件以及在非零输入情况下，落入陷阱的能量作了进一步探讨。     

波纹喇叭差模耦合点的分析

通过对波纹喇叭基本理论的分析,描述了波纹喇叭具有的特殊参数点(低频截止点、快慢波分界线、平衡混合条件、高频截止条件、短路条件)的表达式及特征。以此为依据,详细讨论了在波纹喇叭中主模HE11与差模HE21共存的条件,以及在波纹喇叭内的差模临界截止点的分析。通过寻找到电流或者是电压的波腹点,由此可以更准确选定好开耦合口的位置。     

Higher order asymptotic boundary condition for the finite elementmodeling of two-dimensional transmission line structures

The general form of the solution to Laplace's equation is used to derive a higher-order asymptotic boundary condition. The boundary condition is then implemented in the finite element scheme to model two-dimensional transmission line structures operating in the quasi-TEM mode. The boundary condition is generalized and made valid for an arbitrary outer boundary. The operator is applied on a rectangular outer boundary because that is the most conformable outer boundary for the structures considered. The numerical results of two- and six-conductor configurations showed that the higher-order asymptotic boundary condition yielded a significant improvement over the simple asymptotic boundary condition