双基地多入多出雷达收发方位角联合估计算法

基于多项式求根理论,提出了一种高精度双基地多入多出(Multiple InputMultiple Output,MIMO)雷达收发方位角联合估计算法.该方法通过多项式求根和极小特征矢量法获得二维收发方位角的估值.所提方法无需运算负担繁重的二维伪谱峰值搜索,估得的二维收发方位角由于特征值和特征矢量存在一一对应关系能够自动配对.算法通过链接匹配滤波后的阵列接收数据,产生了虚拟阵元效应,扩展了有效阵列孔径,使得可检测信源数目成倍增长,算法的空间角分辨率更高,角估计性能更优,有效测角范围更加宽广,稳健性更好.仿真实验证明了所提算法的有效性和实用性.     

烧结FeCrAl纤维多孔材料的高温吸声性能

由于航空发动机扇涡轮腔体内为高温环境,需寻找一种吸声材料,此材料既有良好的吸声性能,还有耐高温抗氧化的特殊性能.实验选取FeCrAl纤维为原材料制备烧结纤维多孔材料,在100～500 ℃的测试温度范围内对各样品及梯度结构的吸声性能进行测试,研究温度和厚度对其吸声性能的影响.结果表明,随着温度的升高,吸声系数不再随频率的升高而增大.通过增加材料的厚度也可使吸声性能有较大提高.虽然温度对材料吸声性能影响很大,但梯度结构比单层材料的高温吸声性能好.     

Ellipse-underlay protection algorithm to deal with regional demolishments in mesh optical networks

For the abundant bandwidth, a malfunction in optical networks causes a great deal of loss to traffic, and hence the survivability of optical networks must be considered. Two technologies, protection and restoration, are used in general, and the former is investigated in this paper. The existing protection strategies mainly cope with a single link failure or a double-link failure in an optical network and not consider what causes these failures. In this paper, we study the reasons which lead to the network malfunctions, and pose a new concept named regional demolishment. A protection algorithm named Ellipse-underlay algorithm is also proposed. We compare the performance of the Ellipse-underlay algorithm to the Node-disjoint algorithm. Simulation results show that the Ellipse-underlay algorithm is more effective to the survivability of traffic than the Node-disjoint algorithm.     

EDMA在航迹片段规划系统中的应用

TI公司C6x系列数字信号处理器（DSP）所具有的增强型直接存储器访问方式（EDMA）,相比于DMA配置更加灵活,通道更加丰富。分析了增强型直接存储器访问EDMA2和EDMA3两种传输机制,验证了EDMA3在传输性能上的优势,并将EDMA3方式应用于航迹片段规划系统对大量数据的传输和处理。通过控制EDMA3不仅提高了数据传输速率,而且充分发挥了DSP中央处理单元的快速计算能力。     

激光处理对油松种子老化的修复效应

用He-Ne激光处理贮存五年的油松陈种子 ,用无离子水浸种 30h后析出液的电导率比CK组低 38% ,其发芽率、活力指数最高可达CK组的 14 6 %和 16 9%。试验结果表明 ,适量的激光处理对油松陈种子的老化有修复效应。     

Adaptive ABR congestion control with active buffer control

ATM Forum has defined that the ABR service is designed mainly for data traffic. The design of a simple and efficient congestion control scheme is a problem that network managers have to face. In this paper, we propose a control scheme for ABR service for better scalability and response. The scheme uses both the load level and an increase in queue length to detect the presence of congestion. Continuous control functions are designed for the bandwidth allocation. A better buffer control is achieved by incorporating the percentage of buffer occupancy into the control function. All of the control functions are designed in such a way that they are sensitive to the change of the system states when they are far from the optimal level to get a fast response, but insensitive and change slowly when the states are close to the optimal level to keep the system around the steady state. Our simulation results show that the algorithm is fair to all the connections and it converges fast when the network's condition changes. Copyright © 2001 John Wiley & Sons, Ltd.     

高频雷达电台干扰抑制的稳健最小二乘方法

为对抗工作环境下的非平稳短波电台干扰,本文基于对偶极化的高频地波超视距雷达接收系统提出了新的稳健最小二乘抗干扰算法,改善高频雷达目标检测的性能.该方法基于凸空间最优化的思想,修正水平极化辅助天线接收数据,设定最大的环境误差范围,保证在最差误差环境下的最优干扰抑制性能.通过转换该凸最优的约束方程为简单的一维搜索,提出了最优加权系数的有效求解方法.实验数据处理结果表明了方法的有效性.     

适用于异步徽处理器的16位自定时ALU

针对嵌入式微处理设计中提出的高性能,低功耗的要求,提出了一种面向异步微处理器的由动态电压级联逻辑电路（DCVS）构成的16位自定量ALU。在综合考虑面积、速度、功耗及指令的统计分布情况下,该ALU具有优异的性能。     

慢性滤泡性咽炎的激光治疗与冷冻治疗疗效分析

目的观察慢性滤泡性咽炎,采用两种方法治疗的效果。方法将患者随机分成两组,A组为激光治疗组,B组为冷冻治疗组。结果A组治愈率96%,B组56%。结论激光治疗慢性滤泡性咽炎更有效。     

基于球坐标的非线性小波变换图像压缩编码算法

利用小波变换的3个高频分量之间相关特性,提出了基于球坐标变换的非线性小波变换图像压缩编码的方法,在小波收缩中,采用双曲线收缩处理球坐标下的径向分量以提高重建图像的质量,实验结果表明,此算法在压缩比和重建质量方面都取得较好的效果。