AHMED experiments on hygroscopic and inert aerosol behaviour in LWR containment conditions: experimental results

Hygroscopic NaOH, CsI, CsOH and inert Ag aerosol behaviour at different temperatures and relative humidities (RH) has been studied in a well instrumented and controlled vessel of 1.81 m³ total free volume. Homogeneous thermal-hydraulic conditions for aerosol measurement in the vessel were achieved. The aerosol number and mass concentration were measured continuously during the experiments using a Condensation Nucleus Counter and a Tapered Element Oscillating Microbalance. The particle size distribution and chemical composition in the test conditions were measured by Berner low pressure impactors. In the case of NaOH the half life of the aerosol mass concentration was more than four times longer at low RH (22%) as compared to high RH (96%). The half lives of the CsOH and CsI aerosols were only twice as long at low RH as compared to high RH. Thus at high RH (96–97%) the half lives of CsOH and CsI were twice as long as the half life for the NaOH aerosol. The faster decay of the NaOH aerosol is due to the smaller density decrease of NaOH during water condensation. CsOH particles grew rapidly to their equilibrium size at all humidities. The measured equilibrium size for CsOH aerosol agree well with the calculated particle size at different RHs. Experimental results were also compared with calculations obtained by severe accident computer codes. These calculated results will be presented in a later paper.     

破片撞击下装甲钢层裂破坏的二维MCA方法模拟

高速破片撞击装甲钢的层裂问题,应考虑侧向稀疏波效应的影响．应用二维MCA方法模拟破片高速撞击装甲钢,以元胞速度场直观地描述这种侧向稀疏效应．模拟得到不同速度撞击下,靶板背面的破坏形态和层裂片形貌、分布及飞散速度,符合实际结果．     

一种基于MCA神经网络的数字水印算法

最小主元分析(MCA)在信号处理和数据分析中有重要的应用,故将MCA神经网络应用到数字水印中.该方法可以检测和识别出对原图像的任何修改,并可以用来对完整性和真实性进行检测.该方法另一个非常重要的特性是任何灰度图都可以被嵌入到原图像中,而原有的最低位平面法只能嵌入二进制图像.在水印的提取过程中,需要用户提供公钥来进行解密,因此伪造者是无法修改已有水印并且通过检测的.各种实验证明该方法的各项特性.     

A neural networks learning algorithm for minor component analysis and its convergence analysis

The eigenvector associated with the smallest eigenvalue of the autocorrelation matrix of input signals is called minor component. Minor component analysis (MCA) is a statistical approach for extracting minor component from input signals and has been applied in many fields of signal processing and data analysis. In this letter, we propose a neural networks learning algorithm for estimating adaptively minor component from input signals. Dynamics of the proposed algorithm are analyzed via a deterministic discrete time (DDT) method. Some sufficient conditions are obtained to guarantee convergence of the proposed algorithm.     

跨音速轴流压气机叶片造型及数值仿真

针对跨音速轴流压气机的多圆弧叶片.提出了一种基于锥面展开面的叶片造型方法.设计了某型压气机第一级转子,通过三维粘性流计算软件NUMECA对此孤立转子进行了性能仿真,仿真结果与实验结果符合较好;分析了叶型厚度分布对转子性能的影响:采用标准厚度分布对叶片重新生成,并与多圆弧叶片进行了对比,结果表明用标准厚度生成的叶片更薄一些,性能也更佳;同时当叶型最大厚度的位置后移时,转子的稳定工作范围变宽,效率略有降低.     

氯乙酸间歇生产过程中结晶工序控制方案的建模分析

针对某厂新建的间歇式氯乙酸生产车间结晶工序所使用的预热水罐，通过简要分析得知其控制回路具有耦合性较大和系统易波动的缺点。本文通过建立数学模型，证明将其更换为体积较大的预热水槽，再对预热水槽水位进行恒值控制，可以达到降低系统耦合度，优化系统设计的目的。     

短期负荷预测的MCA与ANN组合模型

针对应用ANN方法时需要处理大量的日负荷数据而影响运算速度的缺点,提出用主成分分析(MainComponent Analysis,MCA)与ANN相结合的组合模型进行预测的方法,在日负荷数据输入神经网络之前用MCA进行处理,“过滤”掉无用的信息成分,以提高负荷预测的效率。仿真结果验证了该组合模型是可行并且高效的。     

氯乙酸间歇生产过程中控制方案的若干改进措施

某厂1999年底建成的年产万吨氯乙酸生产装置采用了自动控制系统。本文在对该自动控制系统进行全面分析之后，针对其结晶釜温度控制方案提出了具体的改进措施,即将原系统使用的预热水罐更换为体积大小合理的预热水槽，并按过程控制原理对预热水槽施加 一定的控制方案，以降低结晶釜夹套的进水预热过程和釜内温度控制过程的耦合度，提高氯乙酸结晶工序的控制性能。     

USING MULTIPLE CORRESPONDENCE ANALYSIS WITH MEMBERSHIP VALUES WHEN THE SYSTEM STUDY YIELDS MISCELLANEOUS DATASETS

This article explains the main role that space windowing plays in preliminary knowledge extraction from multifactor and multivariate databases coming from complex system empirical studies. The explanation is based on the general case of a database with a hyperparallelepipedic structure in which the directions correspond to the factors and where the measurement variables may be quantitative or qualitative, temporal or nontemporal, and objective or subjective. First, the data in each cell of the hyperparallelepiped is transformed into membership values that can be averaged over factors, such as time or individual. Then, several graphic techniques can be exploited to investigate membership values. This article mainly focuses on the use of multiple correspondence analysis (MCA). A didactic example with several factors and several kinds of variables—nontemporal vs. temporal where each one may be either quantitative or qualitative—is used to illustrate the widespread use of the pair “space windowing/MCA.” The discussion presents the advantages and disadvantages of using space windowing to perform a preliminary analysis of a multifactor multivariate system study.     

一种新型现场多道核能谱数据采集系统的设计

介绍了一种新型现场多道核能谱数据采集系统的设计，详细阐述了设计思路，提出了可行性方案，给出了重要功能模块及采取的关键技术，并重点针对现场核能谱数据采集系统的低功耗、实时性和高性能设计进行了研究，最后给出了其主要技术指标及实测Cs标准源谱线，结果表明该系统功能完善，功耗低、性能可靠。