实现交流接触器节电无噪音运行无弧分断的新方法

介绍了一种既能节电无噪音运行又能实现无弧分断的新型交流接触器，即将电力电子器件IGBT、可控硅模块等应用于交流接触器的控制回路和主回路，以实现接触器节电无噪音运行、无弧分断的功能。给出了这种新型交流接触器的设计、工作原理、分析及结论。     

基于无噪协方差矩阵变换的宽带测向算法

宽带测向一直是阵列信号处理领域研究的热点。本文提出了一种基于无噪协方差矩阵变换的宽带测向算法。该算法通过构造变换矩阵,把各个窄带频率处的无噪协方差矩阵变换到聚焦频率处,然后应用子空间的方法得到波达方向估计值。与通常的信号子空间宽带测向算法相比,本文提出的算法不需要对波达方向进行预估计。理论分析证明了本文波达方向估计算法的无偏性。把该算法应用到均匀线阵上,仿真实验结果证明了算法的有效性。     

隐藏有限字符特性的跳空安全传输方法

针对无线数字通信系统,从信息论角度推导了一个保障物理层安全传输的充分条件,并提出了一种隐藏有限字符特性的跳空安全传输方法。首先,在有限字符输入系统中,多天线窃听者具有离散有噪无损信道（Discrete Noisy Lossless Channel ,DNLC ）结构,可以恢复保密信号,致使人工噪声方法失效,因此破坏窃听者的DNLC结构是保证系统传输安全的一个充分条件。然后,利用无线信道特征的多样性和独特性,提出一种基于多输入多输出（Multiple In-put Multiple Output ,MIMO）系统的跳空安全传输方法,在传输信息的过程中随机切换收发天线并发送空域干扰,可以隐藏保密信号的有限字符特性并破坏窃听者的DNLC结构。最后,理论分析和仿真结果表明了该安全方法的有效性。     

Novel matched amplifiers with low noise positive feedback. Part II: Resistive–capacitive feedback

The avalanche modo characteristics of bipolar transistors are considered. A theoretical analysis based on an extension to the Ebers-Moll transistor model is shown to provide satisfactory agreement with various experimental results in the avalanche mode.     

交流接触器无声运行的探讨

本文分析了交流接触器无声运行的工作原理,提出了两类电气控制线路,这是一种实用的节能技术。     

坝腔内混凝土的无声胀裂开挖

无声破碎剂是一种依靠胀力使物体劈裂破坏的新型破碎材料 ,可精确切割或破碎 ,对附近建筑物无任何影响。在桓仁水电站裂缝病坝段内的5号机扩机厂房的基础混凝土开挖中 ,成功地采用了无声破碎剂进行胀裂开挖 ,取得了良好效果     

Novel matched amplifiees with low noise positive feedback. Part 1: General features and resistive feedback

The prominent inventions of D.E. Norton as well as other similar schematics are widely used in different circuits of amplifiers and mixers. However, the use of these circuits in high-frequency integrated circuits (IC) is still hindered by the presence of the broadband feedback transformer. We propose new configuration schematics of transformer-less amplifiers with similar properties. Now we understand implicitly that this opportunity was already contained in our previous patents and papers. Here, the generalised circuit of an amplifier with a complex positive current feedback and with a common base (CB) transistor configuration is considered. Besides, the circuit of low noise amplifier (LNA) with a resistive positive feedback (RPF) is investigated in detail. RPF and CB amplifiers are compared. It is demonstrated that LNA RPF provides gain stability vs scattering of parameters, a good level of the input and output matching, a wider frequency band and the noise temperature more than twice as low as that in CB and, despite a positive feedback, it provides a high stability gain.     

NC8系列交流接触器

NC8系列交流接触器是正泰集团公司自行开发设计的新产品。该产品具有模块化、组合化、小型化的特点。技术性能指标先进，造型美观、新颖。     

Capture Effect of Randomly Addressed Polling Protocol

The capture effect, discussed in this paper, is generally considered to enhance the system's performance in a wireless network. This paper also considers the Randomly Addressed Polling (RAP) protocol in the presence of a fading mobile radio environment. Herein, a deterministic channel, which rules according to inverse power propagation law, is established to obtain the probability that one collided packet can capture the channel from distance distribution. Through the probability, we analyze the performance of the RAP protocol by using an embedded Markov chain. According to our results, the performance of the RAP protocol does not obviously change in terms of power control, implying that it can be more aptly applied in power control skill than other protocols.     

Noiseless Subsystems and the Structure of the Commutant in Quantum Error Correction

The effect of noise on a quantum system can be described by a set of operators obtained from the interaction Hamiltonian. Recently it has been shown that generalized quantum error correcting codes can be derived by studying the algebra of this set of operators. This led to the discovery of noiseless subsystems. They are described by a set of operators obtained from the commutant of the noise generators. In this paper we derive a general method to compute the structure of this commutant in the case of unital noise. PACS: 03.67.–a, 03.67.Pp