Analysis of saltation characteristics of bed-load transport in flowing water

The study of bed-load transport is of great significance both in theory and in practice. This paper discusses the saltation of bed-load solid grains in flowing water. Experiments and theoretic analysis have been made by means of high-speed photographing and advanced data processing technique with a combined method based on mechanical and statistical theories. It indicates that the saltation is the main form of the bed-load transport under ordinary flowing conditions. In the meantime, taking successive saltation as the model of bed-load transport, systematic analysis has been made with regard to the kinematic properties and mechanism of saltation. The statistical analysis shows that the probability density functions of the relative height and length of saltation are in conformity with Γ-type distribution, while the probability density functions of the relative velocities of saltation are in conformity with the Gaussian distribution. The project supported by National Natural Science Foundation of China     

OPNET的网络仿真机制及仿真建模方法

随着计算机技术和通信技术的迅猛发展，网络仿真已成为时下研究、规划、设计网络不可缺少的工具。本文以OPNET为例，在系统研究OPNET网络仿真机制的基础上，着重探讨了OPNET的网络仿真建模方法。     

数字混沌扩频序列的盲估计

混沌序列具有非线性、宽带类噪声、大的码族、任意长的周期且容易产生的特性,因此在扩频通信系统中很有实用价值。本文将文献[1]中对伪随机扩频序列盲估计的方法推广应用到混沌扩频通信中,并对其不足提出了改进方法。在只知道扩频码周期而无其它任何先验知识的条件下,利用特征值分析的方法可以对数字混沌直扩序列进行盲估计,仿真实验证明了该方法的有效性。     

高功率双工旋转场移相器

旋转场移相器具有移相精度高(均方根误差可小于1°)和温度稳定性好等特点,通过改进射频传输结构,可大大提高他的功率容量。利用旋转场移相器的互易特性和铁氧体圆极化器的非互易特性,设计出高功率双工旋转场移相器。其双工特性可将收/发信号分开,实现移相器和环行器的双重功能,用于天线的收发通道等场合时,可省去一个高功率环行器,结构紧凑。分析了双工旋转场移相器的工作原理,阐述了高功率应用下的设计方法,推导出了管状铁氧体的相移量计算公式,按此方法设计了实用的器件,并给出了试验数据。     

火控雷达诱饵系统角度自动控制

在现役雷达抗反辐射导弹的各种措施中,为雷达配置诱饵是较有效、可行的一种。介绍了两点源诱偏的原理,对利用同一类型退役火控雷达作非相干诱饵进行了探讨,提出了一种火控雷达诱饵系统角度自动控制的方法。     

12864-12 LCD模块与射频SoC nRF9E5的串行接口设计

本文首先介绍一种具有2位或3位串行、4位或8位并行多种接口方式，内部含有国标一级、二级简体中文字库的图形点阵液晶显示模块12864-12，以及该模块的技术特性、串行接口方式和操作指令。然后介绍射频片上系统nRF9E5的片内微控制器结构与其接口资源，给出在无线数据传输系统中12864-12与nRF9E5串行连接的硬件电路和部分程序。最后，论述了该方案的优点。     

基于神经网络的雷达辐射源体制和用途智能识别

本文描述一种采用BP神经网络对雷达辐射源体制和用途进行智能识别的方法 ,包括理论分析、神经网络结构设计、推理和学习算法设计、编程算法设计、实验结果比较与分析等。实验表明 ,该方法有着良好的识别效果     

我国有线电视的网络媒体价值

阐述有线电视网络媒体的特点，有线电视网络媒体面临的困境及解决办法，最后展望有线电视网络媒体价值。     

DFB active filter/detector for multichannel FSK optical transmission

In a DFB laser amplifier, used simultaneously as narrow band optical filter and detector in O-FDM systems the increase of the input optical power induces distortion of the filter transfer function. The effect of such a distortion on the receiver sensitivity and dynamic range has been investigated in a 155 Mbit/s FSK direct detection experiment. A two-channel experiment is also reported for the first time. Owing to the effect of interference between the two channels, it has been found that a minimum channel spacing of about 15 GHz is required to maintain the bit error rate below 10/sup -9/.<>     

A novel fermentation process for calcium magnesium acetate (CMA) production from cheese whey

Applied Biochemistry and Biotechnology - A novel, anaerobic fermentation process is developed to produce calcium magnesium acetate (CMA) from cheese whey. CMA can be used as a noncorrosive road...