中国剩余定理与剩余类环Z／（m）上的递归序列

本文基于中国剩余定理给出了一种Z/(m)上递归序列极小多项式的求法和大周期的非线性递归序列的求法,并讨论了线性递归序列之极小多项式的个数,周期和圈数的下界等问题。     

环Z(2~e)上m序列特征多项式的拟周期、本原性的判别与计算

本文给出环Z( 2 e) 上极大长线性递归序列 (m序列 )的特征多项式的拟周期与本原性的判决与计算方法。     

基于时频联合估计的短波OFDM的检测算法

针对短波信道的特点,该文提出了一种OFDM同步检测方案。方案采用m序列调制导频符号,利用时频偏移联合估计得到m序列的相关峰来实现同步检测。该文理论分析了方案中判决门限区间的选取。蒙特卡罗仿真表明,该方案在低信噪比(-10dB)下性能良好,有可靠的同步概率和小的虚警概率。     

环Z/(p~d)上多项式周期的特性

设f(x)是环Z/(p~d)上首一多项式,则f(x)可自然视为Z/(p)上多项式,其中i=1,2,…,d。本文刻划了在各层环Z/(p),2/(p~2),…,Z/(p~d)上f(x)的周期变化情况。     

剩余类环Z/(p~n)上若干类单圈多项式构造

该文研究了剩余类环Z/(pn)上的单圈多项式,其中p 3 5,n 3 2。由于Z/(pn)上单圈多项式的构造可以归结为Z/(p2)上单圈多项式的构造,该文首先给出了Z/(5)上任意次单圈多项式的系数刻画并在此基础上给出了Z/(52)上6次单圈多项式的全部构造。其次,该文给出了Z/(p2)上(p 1)次单圈多项式的部分构造。     

环Z/(m)上线性递归序列的圈数与分布

本文主要讨论了剩余类环Z/(m)上线性递归序列的非平移等价类的个数问题及分布问题。     

基于混沌混合序列的RFID系统流加密方案

在分析了RFID系统所面临的数据安全问题及现有解决方法的基础上,将一种流加密方案用于解决RFID数据安全问题,将m序列和Logistic混沌序列相结合生成一种混沌混合序列,理论分析和计算机仿真结果表明,该混合序列具有良好的随机性、自相关性等许多优良特性,且具有较理想的线性复杂度,适宜作为流加密系统的密钥序列。     

（英）一种新型低暗计数率单光子雪崩二极管的设计与分析

基于0.18 μm互补金属氧化物半导体(CMOS) 图像传感器工艺提出一种新型的低暗计数率(Dark Count Rate)单光子雪崩二极管(SPAD)器件.该器件是利用P+/LNW(Light N-well doping)结检测光子,并通过低浓度的N型扩散圆形保护环抑制边缘击穿,确保其工作在盖格模式.测试结果表明在室温环境下,直径为8 μm的SPAD器件,雪崩击穿电压为14.2 V,当过调电压设置为2 V时,暗计数率为260 Hz,具有低的暗计数率特性.     

无源定位技术的电子战应用

概述了无源定位技术特点，从四个方面进行了分类，总结了现有主要无源定位技术的优缺点。对无源定位面临的现代信号环境（主要指雷达）进行分析，指出主要有三种应用目的：雷达告警（RW）、电了战支援（ES）和电子情报（ELINT）。最后，对无源定位系统涉及到的一些关键指标进行分析，这对无源定位技术的工程化论证过程有参考作用。     

The convex-concave characteristics of Gaussian channel capacity functions

In this correspondence, we give several inherent properties of the capacity function of a Gaussian channel with and without feedback by using some operator inequalities and matrix analysis. We give a new proof method which is different from the method appearing in: K. Yanagi and H. W. Chen, "Operator inequality and its application to information theory," Taiwanese J. Math., vol. 4, no. 3, pp. 407-416, Sep. 2000. We obtain the following results: C/sub n,Z/(P) and C/sub n,FB,Z/(P) are both concave functions of P, C/sub n,Z/(P) is a convex function of the noise covariance matrix and C/sub n,FB,Z/(P) is a convex-like function of the noise covariance matrix. This new proof method is very elementary and the results shall help study the capacity of Gaussian channel. Finally, we state a conjecture concerning the convexity of C/sub n,FB,/spl middot//(P).     

Compression mappings on primitive sequences over Z/(p/sup e/)

Let Z/(p/sup e/) be the integer residue ring with odd prime p/spl ges/5 and integer e/spl ges/2. For a sequence a_ over Z/(p/sup e/), there is a unique p-adic expansion a_=a_/sub 0/+a_/spl middot/p+...+a_/sub e-1//spl middot/p/sup e-1/, where each a_/sub i/ is a sequence over {0,1,...,p-1}, and can be regarded as a sequence over the finite field GF(p) naturally. Let f(x) be a primitive polynomial over Z/(p/sup e/), and G'(f(x),p/sup e/) the set of all primitive sequences generated by f(x) over Z/(p/sup e/). Set /spl phi//sub e-1/ (x/sub 0/,...,x/sub e-1/) = x/sub e-1//sup k/ + /spl eta//sub e-2,1/(x/sub 0/, x/sub 1/,...,x/sub e-2/) /spl psi//sub e-1/(x/sub 0/,...,x/sub e-1/) = x/sub e-1//sup k/ + /spl eta//sub e-2,2/(x/sub 0/,x/sub 1/,...,x/sub e-2/) where /spl eta//sub e-2,1/ and /spl eta//sub e-2,2/ are arbitrary functions of e-1 variables over GF(p) and 2/spl les/k/spl les/p-1. Then the compression mapping /spl phi//sub e-1/:{G'(f(x),p/sup e/) /spl rarr/ GF(p)/sup /spl infin// a_ /spl rarr/ /spl phi//sub e-1/(a_/sub 0/,...,a_/sub e-1/) is injective, that is, a_ = b_ if and only if /spl phi//sub e-1/(a_/sub 0/,...,a_/sub e-1/) = /spl phi//sub e-1/(b_/sub 0/,...,b_/sub e-1/) for a_,b_ /spl isin/ G'(f(x),p/sup e/). Furthermore, if f(x) is a strongly primitive polynomial over Z/(p/sup e/), then /spl phi//sub e-1/(a_/sub 0/,...,a_/sub e-1/) = /spl psi//sub e-1/(b_/sub 0/,...,b_/sub e-1/) if and only if a_ = b_ and /spl phi//sub e-1/(x/sub 0/,...,x/sub e-1/) = /spl psi//sub e-1/(x/sub 0/,...,x/sub e-1/) for a_,b_ /spl isin/ G'(f(x),p/sup e/).     

Step Response of Lossless Nonuniform Transmission Lines with Power-Law Characteristic Impedance Function (Short Paper)

The step-response waveform of the Iossless nonuniform transmission line possessing a characteristic impedance function Z/sub c/(x)= Z/sub 0/(1 + eta x)/sup 2n/, n = 0,1,2,..., is deduced. The simple and closed-form solutions should be useful for pulse transient analysis involving nonuniform transmission lines.     

A LARGE CLASS OF BINARY ZCZ SEQUENCE FAMILIES CONSTRUCTED BY PERIOD DOUBLING

In an Approximately Synchronized Code Division Multiple Access （AS-CDMA） communication system, a family with large number of Zero Correlation Zone （ZCZ） sequences is desired, which can satisfy the rapid increase of users. This paper presents a method to generate a （2L,2M, ZCZ＇）-ZCZ sequence family from an original （L,M,ZCZ）-ZCZ sequence family, where ZCZ＇ = ZCZ if ZCZ is even and ZCZ＇ =ZCZ - 1 if ZCZ is odd. This method can also recursively act on a ZCZ sequence family to construct a series of ZCZ sequence families with large sequence number and zero correlation zone length identical to or one less than that of original ZCZ sequences.     

Influence of the Cu(In,Ga)Se2 thickness and Ga grading on solar cell performance

Thin‐film solar cells with Cu(In,Ga)Se₂ (CIGS) absorber layers ranging from 1.8 to 0.15 μm in thickness were fabricated by co‐evaporation, with both homogeneous and Ga/(Ga + In) graded composition. The absorption of the CIGS layers was determined and compared with corresponding QE measurements in order to obtain the optical related losses. The material characterization included XRD as well as cross‐sectional SEM analysis. Devices with CIGS layers of all thicknesses were fabricated, and down to 0.8–1 μm they showed a maintained high performance (η ∼ 15%). When the CIGS layer was further reduced in thickness the loss in performance increased. The main loss was observed for the short‐circuit current, although the loss was not only due to a reduced absorbance. The open‐circuit voltage was essentially not affected by the reduction of the CIGS thickness, while the fill factor showed a slight decrease. The fill factor loss was eliminated by introducing a Ga/(Ga+In) graded CIGS, which also resulted in an increased open‐circuit voltage of 20–30 mV for all CIGS thicknesses. Device results of 16.1% efficiency at 1.8 μm CIGS thickness, 15.0% at 1.0 μm and 12.1% at 0.6 μm (total area without anti‐reflective coating) were achieved. Copyright © 2002 John Wiley & Sons, Ltd.     

Wide-sense nonblocking multicast Log/sub 2/(N,m,p) networks

Recently, Tscha and Lee proposed a fixed-size window algorithm for the multicast Log/sub 2/(N,0,p) network and expressed a desire to see its extension to the Log/sub 2/(N,m,p) network. Later, Kabacinski and Danilewicz generalized the fixed-size window to variable size to improve the results. In this paper, we further extend the variable-size results from the Log/sub 2/(N,0,p) network to Log/sub 2/(N,m,p). Note that this extension is difficult since each link in the channel graph of Log/sub 2/(N,0,p) has the same blocking effect, but not so in Log/sub 2/(N,m,p). We also determine the optimal window size and optimal m.     

Al薄膜对(002)ZnO/Al/Si结构基片中ZnO薄膜特性影响的实验研究

采用射频磁控溅射法沉积制备了(002)ZnO/A l/Si复合结构。研究了Al薄膜对(002) ZnO/Al/Si复合结构的声表面波器件(SAWD)基片性能影响以及当ZnO 薄膜厚度一定时的Al膜最佳厚度。采用X射线衍射(XRD)对Al和ZnO薄膜进行了结构表征 ,采用 扫描电镜(SEM)对ZnO薄膜进行表面形貌表征,并从薄膜生长机理角度进行了分析。结果 表明,加Al薄膜有利于ZnO薄膜按(002)择优取向生长,并且ZnO 薄膜的结晶性能提高;与(002)ZnO/Si结构基片相比,当Al薄膜 厚为100nm时,(002)ZnO/Al/Si结构中ZnO薄 膜的机电耦合系数提高 了65%。     

Closed form and infinite series solutions for the MGF of a dual-diversity selection combiner output in bivariate Nakagami fading

Using a circular contour integral representation for the generalized Marcum-Q function, Q/sub m/(a,b), we derive a new closed-form formula for the moment generating function (MGF) of the output signal power of a dual-diversity selection combiner (SC) in bivariate (correlated) Nakagami-m fading with positive integer fading severity index. This result involves only elementary functions and holds for any value of the ratio a/b in Q/sub m/(a,b). As an aside, we show that previous integral representations for Q/sub m/(a,b) can be obtained from a contour integral and also derive a new, single finite-range integral representation for Q/sub m/(a,b). A new infinite series expression for the MGF with arbitrary m is also derived. These MGFs can be readily used to unify the evaluation of average error performance of the dual-branch SC for coherent, differentially coherent, and noncoherent communications systems.     

Three-step impedance criterion for small-signal stability analysis in two-stage DC distributed power systems

Small-signal stability analysis methods based on an impedance criterion originate from the minor loop gain method and are gradually utilized in two-stage DC distributed power systems. In this paper, we conclude that the impedance criterion directly dependent on output impedance Z/sub o/(s) of the source subsystem and input impedance Z/sub i/(s) of the load subsystem is possible but gives an incorrect stability analysis for systems with a regulated source subsystem. Through introducing a mapped pure impedance of the load subsystems and the preliminary system, we develop a general three-step impedance criterion, with which a correct small-signal stability analysis can be guaranteed, regardless of the type of source subsystem. Furthermore, we introduce the application of the three-step impedance criterion in two small-signal stability analysis cases and utilize it in an example system to predict the stability shift process arising from the variation on the load resistance and input voltage value.