三峡水库蓄水期城陵矶与长沙站水位关系分析

为了解三峡水库蓄水期间城陵矶与长沙水位的关系,通过建立洞庭湖城陵矶站不同水位与湘江长沙站水位流量相关关系,分析城陵矶站对长沙水位的影响.根据MIKE11水动力学模型,分析计算枯水期长江干流宜昌站、湘江湘潭站不同来水条件下城陵矶、长沙水位及其相关关系,进而分析了三峡水库蓄水期不同因素对长沙站水位的影响情况,认为在2008...     

资水梯级电站施工期闸孔通航方式工程实践

有通航要求的水利水电工程施工期通航问题,是施工导流设计和工程实施期间需要妥善解决的问题之一。以资水柘溪电站以下河段修建的修山水电站、东坪水电站和株溪口水电站工程为例,介绍了施工期利用工程既有的闸孔通航并取得较好技术经济效果的实际做法。工程实践表明,利用闸孔通航,技术上是可行的,并具有导流程序简单、施工期通航工程措施费用低、电站发电时间可提前等优点,经济效益显著。其工程经验可在类似工程中推广应用。     

基于LFSR的钟控密钥流生成器

本文提出了一种基于LFSR的钟控密钥流生成器。该生成器通过一个钟控线性移位寄存器从15个级数是两两互素的线性移位寄存器中控制选取10个,将所选出的各线性移位寄存器生成的m序列相加,然后输出,从而达到了伪随机序列周期扩大的目的。本文还对密钥流生成器的线性复杂度、均匀性、相关性以及游程特性进行了分析。分析表明,该生成器生成序列的周期能达到2128,而且有较大的线性复杂度和良好的相关性和均匀性。认为该序列可以作为密钥流序列进行加密。通过钟控的方式随机选取用于相加的m序列,增加了密钥流序列的条数。此外,本文还给出了该生成器的具体实现算法,有一定的实用价值。     

基于主动变采样周期方法的网络控制系统的H∞控制器设计

This paper studies the problem of designing H∞ controllers for networked control systems (NCSs) with both network-induced time delay and packet dropout by using an active-varying sampling period method, where the sampling period switches in a finite set. A novel linear estimation-based method is proposed to compensate packet dropout, and H∞ controller design is also presented by using the multi-objective optimization methodology. The simulation results illustrate the effectiveness of the active-varying sampling period method and the linear estimation-based packet dropout compensation.     

Simultaneous measurement of temperature and strain with long period grating pairs using low resolution detection

An investigation showing the performance of compact long period grating (LPG) pairs under demanding experimental conditions, making comparisons with the use of single LPGs for the simultaneous measurement of strain and temperature is presented. In this work, a LPG pair (LPGP) sensor comprising two weak (2.5 dB each) LPGs, 13 mm apart, was compared against the performance of two single LPG sensors (LPG1 & LPG2) with coupling strengths of 2.5 dB and 12.5 dB, respectively. All the LPG sensors used were subjected to extreme conditions arising from the fabrication, by choosing a high amplitude mask period with short physical length LPGs, and the high temperature annealing processes. In addition, a low resolution detection instrument was used to capture the spectra under study. Results have shown that the LPGP is 40 times better than the first single LPG used (LPG1) and three times better than the second LPG (LPG2). Using the error analysis methodology of Brady et al., the temperature and strain errors due to the uncertainty of the wavelength measurement for each of the LPG1, LPG2, and LPGP were compared with the typical performance of various fibre Bragg grating (FBG)-based sensor schemes under similar testing conditions. It was found that LPGPs offer the best performance especially when using low resolution detection instrumentation.     

JSF技术在J2EE平台下的优势分析

JSF是真正的MVC模式,它的侧重点是Web表现层,提供了丰富的页面开发控件,而且支持控件的开发,方便、灵活.JSF使开发人员以拖拽的方式使用控件来布局Web页面,简单而又美观,克服了Java在Web开发中不可视化的缺点.J2EE是强大的企业级系统开发平台,其架构在三层Web系统中有着得天独厚的优势.JSF在J2EE平台下的应用,弥补了Java在Web开发方面的不足,非常适用于中小型三层Web系统的快速应用开发.     

Computational simulation of Belousov–Zhabotinskii oscillating chemical reaction

The suitability of computational simulation of the Belousov–Zhabotinskii oscillating chemical reaction by differential kinetic methodology for resolving nonlinear multi-component system is demonstrated in this work. According to the Field–KÖrÖs–Noyes mechanism and the Oregonator model, the change of the concentrations of HBrO₂, bromide ion and cerium ion are simulated. The results of computational simulation are consistent with experimental results very well. At the same time, the effect of variables and parameters, especially the rate constant on the oscillation curve, are investigated deeply. A simple method of estimating rate constants is obtained through simulation the concentrations of key components of the system, and then comparison the simulation results with the experimental ones. The reasonable rate constant is also proposed.     

基于长周期光纤光栅的生物传感器设计及仿真

利用生物活性物质高效、专一的催化特性,通过生化反应中生成的复合物对包层折射率和半径的直接调制,提出了基于长周期光纤光栅的、可用于蛋白质等生物物质鉴别与分析的传感方案,并用数值计算方法对检测中所生成复合物薄膜层的折射率和厚度变化对耦合波长偏移和衰减的影响进行了仿真研究,为新型高灵敏度生物传感器的研发提供了理论依据。     

双闭环真空硅微陀螺仪设计及测试性能分析

所设计的硅微陀螺仪工作在10 Pa,品质因素达到3000,采用CAN金属壳封装形式,测控线路采用闭环自激驱动,力反馈式闭环检测方式.驱动采用单边驱动单边检测,尽量使线路简化;检测采用双重分解和重构回路.测试结果表明:有用信号和正交信号实现很好的相位解耦,互不影响.在实现标度因素10 mY/(°)S-1的情况下,零偏稳定性已达到了60°/h;线性度已达到了400 ppm;带宽仿真达到150 Hz;这较以前设计的空气下闭驱开检方式下的硅微陀螺性能提高了近2个数量级.     

基于Mumford-Shah模型和G空间的图像结构纹理分解

构造了一个变分问题来实现图像的纹理结构分解.其中结构成分用分段光滑的函数(即Mumford-Shah模型)刻画,纹理部分用振荡函数(G空间)来描述.由于Mumford-Shah模型将结构成分显式地描述为分段光滑函数,在非结构边缘点处的梯度采用L2范数约束,故相对于全变差(Total variation,TV,梯度的L1范数)的分解方式,很好地克服TV带来的阶梯效应;G空间本身定义的纹理函数的振荡特性保证了分解的结构成分中含有更少的纹理信息.实验表明,无论相对于经典的TV-L2分解还是TV-G分解,本文方法均体现出了很好的分解性能.