电流并联负反馈放大器实验的研究

用实验的方法，研究电流并联负反馈对放大器性能的改善，提出电流型、并联型负反馈放大器性能参数的测量方法。     

Separate Polarization Modes Synchronization and Synchronization Switches between Vertical-Cavity Surface-Emitting Lasers

For vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated feedback, there exist several synchronization types such as synchronizations between total powers and synchronizations between separate polarization modes. Based on the two-mode rate equations, we study and compare numerically the performances of different synchronization types. Our results show that three synchronization types exhibit good performances when their synchronization conditions are satisfied. They are the complete synchronization between total powers, complete synchronization between x-polarized modes, and generalized synchronization between x-polarized and y-polarized modes. The former two types are sensitive to the injection rate and spontaneous emission, while the third type is contrary. Synchronization type with the best performance may switch from one to another, with changing of injection rate and spontaneous emission factor.     

增强型延迟反馈法控制低维混沌系统的解析研究

基于时间延迟反馈控制混沌系统的方法,提出一种增强型控制方案,并利用分析延迟系统产生Hopf分支条件的方法,给出这种方案控制低维连续自治混沌系统时,在达到控制目标的条件下,控制参数的一般解析关系.将这一方案和分析方法应用到两个混沌模型中,结果表明:采用修正的方案可以明显地改善控制混沌的效果和质量;解析分析的结果与实际数值计算的结果一致. 关键词： 延迟反馈 混沌控制 Hopf分支     

Selection of meaningless steady noise for masking of speech

This paper focuses on masking speech with meaningless steady noise as a way of realizing a comfortable sound environment. As a basis for research, meaningless steady noise at minimum sound pressure levels for masking of male or female meaningful speech is considered, based on psychological experiments using a method of adjustment. From the results, band-limited pink noise can be selected as the most effective noise for masking of speech. In the case of speech with a lower sound pressure level, the sound pressure level of the meaningless steady noise needs to be a little higher.     

Submicrometric Displacement and Vibration Measurement Using Optical Feedback in a Fiber Laser

A very simple and efficient technique for the remote sensing of a noncooperative target is presented. This technique is based on the frequency-shifted reinjection of light in a class B laser. Ytterbium- and erbium-doped fiber lasers have both been used to measure displacements with a submicrometric resolution and the vibration power spectrum of an object.     

一种控制掺铒光纤激光器超混沌的方法——非线性延时反馈参数调制法

提出一种非线性延时反馈参数调制法来控制混沌/超混沌，给出了利用这种方法控制处于超混沌状态的双环掺铒光纤激光器的方案.数值模拟表明，只要延时时间和反馈强度合适就可以把双环掺铒光纤激光器从超混沌状态成功地控制到不同的周期状态. 关键词： 掺铒光纤激光器 超混沌 非线性延时反馈参数调制 混沌控制     

HL—1装置等离子体密度反馈实验

本文叙述HL-1装置用反馈脉冲补充送气方式控制等离子体密度的方法及实验结果。给出了在固有的物理实验条件下的最佳反馈方式,实现了对密度的有效控制及反馈。讨论了在不同密度条件下的几种反馈方式及反馈系统尚存在的不足之处。     

经纬仪二轴正交调整方法

本文叙述了经纬仪二轴正交调整的四种方法,其中对偏反射镜法作了理论分析。     

Numerical Approximation and Error Analysis for the Timoshenko Beam Equations with Boundary Feedback

In this paper,the numerical approximation of a Timoshenko beam with bound- ary feedback is considered.We derived a linearized three-level difference scheme on uniform meshes by the method of reduction of order for a Timoshenko beam with boundary feedback.It is proved that the scheme is uniquely solvable,unconditionally stable and second order convergent in L_∞norm by using the discrete energy method. A numerical example is presented to verify the theoretical results.     

三代像增强器用微通道板的改进与发展

简要说明了三代像增强器的特点，分析了微通道板的离子反馈形成机理，给出有效抑制离子反馈对光阴极造成伤害的2种方法，即一种是减少和清除微通道板的吸附气体，另一种是阻止反馈离子反馈到光阴极上。介绍了国外最新的三代像增强器，以及使用优化改进的高性能微通道板显著减薄甚至彻底去除微通道板离子反馈膜的方法，该方法能维持砷化镓光阴极足够长的工作寿命，还介绍了最新发展的体导电微通道板和硅微通道板。指出高可靠性无膜选通砷化镓像增强器技术的实现，不仅需要微通道板在抑制离子反馈方面取得突破，还需要砷化镓光阴极在耐受离子反馈能力上进一步提高，同时还要结合和拓展选通电源的应用。