Modelling of a gas flow measurement: Application to nuclear containment vessels

The objective of this work is to simulate the gas flow across a concrete wall of a nuclear power plant internal enclosure. In the laboratory, permeability measurements are generally made on cylindrical samples (15 cm diameter×5 cm height: ∅ 15×5 cm) with a steady-state experiment. To be able to predict structural behaviour, we studied size effect and steady-state time with a modified CEMBUREAU permeability test. A statistical approach showed that there is no size effect on concrete permeability. Laboratory results found on cylindrical samples can be applied to tests in situ, where concrete specimens are thicker. A model based on the mass balance relation provided times to reach steady state and reproduced experimental flow kinetics for uniform water content across specimens.     

广播电视农村覆盖现状浅析

加强农村广播电视的发展,提高其覆盖率是关键,针对这一问题,阐述了解决农村广播电视覆盖的手段,对农村广播电视覆盖现状做了详细的分析,并提出建议和措施。     

全双极WTA模型的改进及其实现

提出了一种相似度的新定义，使双极ＷＡＴ模型的实现更加简洁明了。增加一个阈值使系统能判别非存储模式或因其信息量过低而无法鉴定的输入模式，阈值的大小与要求的容错能力有关。双极相似度及阈值通过光学方法实现。阈值的光学实现使系统仍具有照明不变性。通过电路实现取及ＷＴＡ网络的迭代运算。     

IPA模型对Hopfield模型神经网络的改进

考虑Ｈｏｐｆｉｅｌｄ模型中假态之间的布尔逻辑关系，提出利用ＩＰＡ模型对神经网络中的假态进行抑制，并和原网络的性能进行了比较，结果表明：改进后的网络性能比Ｈｏｐｆｉｅｌｄ模型和ＩＰＡ模型均有较大提高。     

DIGITAL PROCESSING OF THE POLARIZATION STATE OF GEOPHYSICAL ULF SIGNALS

In this paper, the evaluation by running window smoothing is used for the digital processing of the polarization of geophysical ULF signals. The observed signals are resolved into two orthogonal complex components so that it is no longer necessary to consider the phase and amplitude of the signals simultaneously.     

用稳态反饱和吸收法测量C_（60）的激发态吸收截面

用准连续激光实现了Ｃ６０的稳态反饱和吸收，通过实验和理论计算的拟合，确定了Ｃ６０的三重第一激发态吸收截面。     

无线数据通信网发展趋势

无线数据通信具有两大发展趋势，即低速的广域移动数据网及高速的局域无线数据网。本文介绍了其技术特点、应用情况和市场前景，分析了无线数据通信传输技术、网络结构和媒质接入控制等问题。     

Random Vibration of Systems with Viscoelastic Memory

The equation of motion of linear dynamic systems with viscoelastic memory is usually expressed in a integrodifferential form, and its numerical solution is computationally heavy. In two recent papers, the writers suggested that the system memory be accounted for through the introduction of a number of additional internal variables. Following this approach, the motion of the system is governed by a set of first-order, linear differential equations, whose solution is quite easy. In this paper, the approach is extended to single-degree-of-freedom systems subjected to random, nonstationary excitation. The equations governing the time variation of the second-order statistics are derived, and an effective step-by-step solution procedure is proposed. Numerical example shows the accuracy of the procedure for white and nonwhite excitations.     

A Novel Channel Predictor Based on Constrained Hidden Markov Model

1　Introduction　Linkadaptationtechniqueisnowwidelyrecognizedasakeysolutiontoincreasethespectralefficiencyofwire lesssystems[1～ 3] .GPRS ,EDGE ,cdma2 0 0 0andWCDMAallincludelinkadaptationasameanstopro videhigherdatarates[4～ 5] .Torealizethepotentialoflinkadaptation ,reliablechannel predictionisneces sary[6 ] .　Therearemanydifferentchannelpredictionmethodsavailablenow ,suchasLongRangePrediction(LRP) [6 ] ,predictionbasedonsubspacesignalprocess ingalgorithms[7] ,predictionbasedonFinit…     

精馏塔静态仿真：Ⅰ.静动态混合数学模型的应用

本文为了克服精馏塔静态仿真不易收敛和初值难以给定等难题，巧妙地利用隐含数值积分方法的特点，将稳态与动态数学模型耦合起来，用以求解高难度的非理想精馏塔静态仿真问题。所得静动态混俣模型大大提高了精馏塔静态仿真的鲁棒性，对于高度非理想精馏塔的仿真尤为有效。通过对某丙烯腈萃取精馏塔的静态仿真，充分证明了这种混合模型化方法的可行性。