矸石架头主钢梁变形分析及校正

淮北矿业集团公司许疃煤矿是年产300万t的现代化大型矿井,建井期间,为了减少工业广场面积,节约土地,主副井的泥浆都倾倒在矸石山地基下面,淮南矿业集团公司矿井的矸石山也有类似情况.     

"电路与电子技术实验"教学改革

针对独立学院人才培养的特点,对中国计量学院.电路与电子技术实验"在实验内容、实验模式、实验教学手段、开放式实验教学及实验考核制度等多方面开展的改革进行了介绍.这些改革有效地提高了实验课程的教学质量,体现了以"以生为席"的教育理念.     

知识管理与知识传播——论图书馆学与传播学的融合

在图书馆用户导向的服务理念下,知识管理与知识传播将会是图书馆发展的两项重要工作,吸收和借鉴传播学的理论和实践是图书馆做好知识传播工作的关键。从图书馆学与传播学共同面对的知识和信息入手,阐述了图书馆和传播学的历史渊源、理论和实践的融合。     

An efficient algorithm for electromagnetic scattering from rough surfaces using a single integral equation and multilevel sparse-matrix canonical-grid method

An efficient algorithm for wave scattering from two-dimensional lossy rough surfaces is proposed. It entails the use of a single magnetic field integral equation (SMFIE) in conjunction with a multilevel sparse-matrix canonical-grid (MSMCG) method. The Rao-Wilton-Glisson (RWG) triangular discretization is adopted to better model the rough surface than the pulse basis functions used in the well-established SMCG method. Using the SMFIE formulation, only one unknown per interior edge of the triangular mesh approximating the rough surface is required, and the iterative solution to the moment equation converges more rapidly than that of the conventional coupled equations for dielectric rough surfaces. The MSMCG method extends the applicability of the SMCG method to rougher surfaces. Parallel implementation of the proposed method enables us to model dielectric surfaces up to a few thousand square wavelengths. Simulation results are presented as bistatic scattering coefficients for Gaussian randomly rough surfaces.     

谐波参数测试方法探讨

提出了一种采用测量接收机测试射频信号源谐波参数的方法,并对该方法的特点、应用范围进行了分析,进而实现了该方法的自动化测试,解决了在没有频谱分析仪的情况下测试射频信号源谐波参数的问题。     

光纤量子密钥分发系统中密钥传输率和误码率的研究

通过理论分析和计算,研究了光纤损耗、色散和单光子探测器暗计数等因素对量子密钥分发系统密钥传输率和误码率的影响.研究表明,光纤损耗是影响密钥传输率的主要因素.而量子比特误码率则与光纤损耗、色散、脉冲宽度、单光子探测器暗计数以及瑞利反向散射等因素有关.在实验中,应尽量降低光纤损耗、色散和单光子探测器的暗计数,同时选择适当的初始脉宽,从而提高密钥传输率并降低误码率,进而提高量子密钥分发系统的传输距离.     

GaAs MMIC MESFET混频器性能比较

给出了几种 Ga As MESFET单片混频器结构与芯片测试结果比较。实验表明 ,在相同本振功率激励下 Ga As MMIC双栅混频器具有良好变频特性 ,栅混频器指标次之 ,漏混频器结构最简单 ,但变频特性不如前两种。另外 ,单片巴仑双平衡混频器具有高的动态范围和宽频段工作特点。     

基于PROTEUS的数控恒流源设计与仿真

为了克服传统单片机开发过程中存在的硬件成本高、开发速度慢等诸多弊端,介绍了采用EDA仿真软件PROTEUS开发的数控恒流源系统。给出了系统硬件电路设计方案和在Keil环境下开发的主要程序代码。AT89C52单片机控制TLC5615串行D/A转换器输出锯齿形电压信号,此电压信号经电压电流转换电路转换产生稳定的线性电流信号。在PROTEUS环境中完成了软件和硬件的仿真,验证了设计方案的可行性。设计过程简单方便,降低了开发成本,设计效率得到大大提高。     

Robust Constrained Model Predictive Control Based on Parameter-Dependent Lyapunov Functions

The problem of robust constrained model predictive control (MPC) of systems with polytopic uncertainties is considered in this paper. New sufficient conditions for the existence of parameter-dependent Lyapunov functions are proposed in terms of linear matrix inequalities (LMIs), which will reduce the conservativeness resulting from using a single Lyapunov function. At each sampling instant, the corresponding parameter-dependent Lyapunov function is an upper bound for a worst-case objective function, which can be minimized using the LMI convex optimization approach. Based on the solution of optimization at each sampling instant, the corresponding state feedback controller is designed, which can guarantee that the resulting closed-loop system is robustly asymptotically stable. In addition, the feedback controller will meet the specifications for systems with input or output constraints, for all admissible time-varying parameter uncertainties. Numerical examples are presented to demonstrate the effectiveness of the proposed techniques.     

移动信息技术的应用研究

随着智能手机及平板电脑等终端产品的普及,智能移动终端越来越多地参与到人们的生产和生活中,影响着人们日常生活的方方面面。3G和4G的高速移动网络技术革新为移动信息时代的来临奠定了技术基础,社会正全面迈向移动信息时代。移动信息技术给企业业务经营方式带来巨大变革,从“有形收益”和“无形价值”两个方面实现了企业竞争优势的提升;移动信息技术使人们生活更便捷,对社会经济、文化、科技等领域产生了重大影响。这里整理了移动技术的相关应用,并结合移动技术的特点,对移动信息技术的应用前景进行了分析。