深圳抽水蓄能电站上水库主坝坝型选择

本文着重介绍了在可研究性阶段,通过对深圳抽水蓄能电站上水库主坝设计过程中坝型选择的相关因素的分析,确定其大坝类型的过程。     

Resource management in the next-generation DS-CDMA cellular networks

Direct sequence code-division multiple access has been shown as the predominant access technology to provide high-speed multimedia services in next-generation wireless cellular networks. The DS-CDMA cellular network significantly differentiates itself from the traditional narrowband TDMA/FDMA system, in which great capacity gain can be explored by taking advantage of its unique characteristics. This article addresses resource management in DS-CDMA cellular networks. We first provide an overview of the DS-CDMA network and discuss the main challenges in the design of resource management schemes. We then examine several critical issues within the scope of resource management, including congestion control, rate and power control, and cell planning, with the emphasis on call admission control. Finally, we offer some insights and discussions on the performance aspects, strengths, and weaknesses of existing proposals.     

In situ polymerization and characterization of polyester‐based polyurethane/nano‐silica composites

Polyester‐based polyurethane/nano‐silica composites were obtained via in situ polymerization and investigated by Fourier‐transform infrared spectroscopy (FTIR), or FTIR coupled with attenuated total reflectance (FTIR‐ATR), Transmission electron microscopy (TEM), atomic force microscopy (AFM), an Instron testing machine, dynamic mechanical analysis (DMA) and ultraviolet‐visible spectrophotometry (UV‐vis). FTIR analysis showed that in situ polymerization provoked some chemical reactions between polyester molecules and nano‐silica particles. FTIR‐ATR, TEM and AFM analyses showed that both surface and interface contained nano‐silica particles. Instron testing and DMA data showed that introducing nano‐silica particles into polyurethane enhanced the hardness, glass temperature and adhesion strength of polyurethane to the substrate, but also increased the resin viscosity. UV‐vis spectrophotometry showed that nano‐silica obtained by the fumed method did not shield UV radiation in polyurethane films. Copyright © 2003 Society of Chemical Industry     

广义预测控制系统的仿真软件设计与开发

介绍了基于广义预测控制的模型预测控制（MPC）系统仿真软件的开发与实现过程。该软件包含了MAC，IMAC，DMC，DDMC和GPC五种预测控制算法，可以用不同的方法实现对预测控制系统的综合性仿真以及控制器参数的调整。利用该软件可对模型预测控制系统的作用机理做进一步仿真分析，并有助于定性分析各种算法中设计参数对系统性能的影响以及不同算法之间的区别。     

Photoreactivation of Escherichia coli following medium-pressure ultraviolet disinfection and its control using chloramination.

Ultraviolet (UV) disinfection is becoming increasingly popular as an alternative disinfection technology to chlorination in recent years. In this study, we investigated the photoreactivation of Escherichia coli following medium-pressure (MP) UV disinfection of synthetic water by a bench-scale collimated beam apparatus. The UV doses ranged from 1.6 -19.7 mWs/cm2 and photoreactivation was investigated for 6 hours under fluorescent light. In addition, chloramination was applied after UV disinfection to investigate its ability to control photoreactivation. It was found that photoreactivation occurred for all UV doses tested and the increase in bacteria numbers ranged from 0.04 to 1.35 log10. However, the degree of photoreactivation decreased with increased UV doses. Chloramination experiments revealed that the addition of 0.5 mg/l of monochloramine resulted in suppression of photoreactivation for 1 hour only. An increased monochloramine dose of 1 mg/l was found to prevent photoreactivation for the entire duration of the experiment. The results of this study have shown that photoreactivation occurs even after MP UV disinfection, although it is of a lesser extent at higher UV doses. This study has also established that secondary chloramination can effectively suppress and eliminate photoreactivation with a chloramine dose of 1 mg/l.     

立方相GaN的持续光电导

研究了金属有机物化学气相外延 (MOVPE)方法生长的非故意掺杂的立方相 Ga N的持续光电导效应 .在六方相 Ga N中普遍认为持续光电导效应与黄光发射有关 ,而实验则显示在立方 Ga N中 ,持续光电导效应与其中的六方相 Ga N夹杂有关系 ,而与黄光发射没有关系 .文中提出 ,立方相 Ga N与其中的六方相 Ga N夹杂之间的势垒引起的空间载流子分离是导致持续光电导现象的物理原因 .通过建立势垒限制复合模型 ,解释了立方相 Ga N的持续光电导现象的物理过程 ,并对光电导衰减过程的动力学作了分析 .对实验数据拟合的结果证明以上的模型和推导是与实验相符的 .     

Solution of large deformation contact problems with friction between Blatz-Ko hyperelastic bodies

The present paper is devoted to the analysis of the contact problems with Coulomb friction and large deformation between two hyperelastic bodies. One approach to separate the material nonlinearity and contact nonlinearity is presented. The total Lagrangian formulation is adopted to describe the geometrically nonlinear behavior. Nondifferentiable contact potentials are regularized by means of the augmented Lagrangian method. Numerical examples are carried out in two cases: rigid-deformable contact and deformable-deformable contact with large slips. The numerical results prove that the proposed approach is robust and efficient concerning numerical stability.     

A generalized equation for the prediction of melting temperatures of homopolymers and copolymers

A generalized equation was derived to calculate the melting temperatures of homopolymers and copolymers. The Gibbs‐Thomson equation for homopolymers and a modified application to copolymers were derived using the proposed equation. The melting temperature T_m⁰ in the Flory equation corresponds to the melting temperature T_m^C,∞ of copolymer crystals with stems of infinite length. Also, T_m^C,n*, the melting temperature for copolymer crystals with stems containing the maximum possible number of structural units, n*, should be used instead of T_m⁰ as the basis of supercooling in crystallization. The proposed equation shows good agreement with experimental data for α‐alkene‐ethylene homogeneous copolymers.     

中温换热器检查及修复方案

经分析认为中温换热器缺陷出现的主要原因是H2 S腐蚀。采取更换短管以及补焊上段下管板的措施进行修复 ,取得了满意的效果     

Bi3+对纳米MnO2水热合成的影响研究

在中性和酸性条件下，以MnO2作为锰源，通过水热合成了纳米MnO2，通过XRD和TEM对产物进行的观察表明，在酸性条件下，向溶液中添加一定量的Bi^3 ，产物的晶型由α型向γ型转化，产物形貌由针状、丝状向颗粒状转变。