微型反应堆照射座内热中子通量谱的测定

一、基本原理用一组展开函数?_i(E)来表示所测的真实谱φ(E),典型的展开函数是一组N—1项的多项式,N是探测箔种类数。     

Measurement of single electrode potentials and impedances in hydrogen and direct methanol PEM fuel cells

A commercial proton exchange membrane fuel cell has been fitted with a simple dynamic hydrogen reference electrode (DHE). Single electrode potentials and impedances measured with hydrogen and methanol as the fuel have been critically evaluated. It has been shown that the anode overpotential and impedance can be very significant in hydrogen cells operated at ambient temperature, due to dehydration of the anode. The DHE provides a powerful way of monitoring the hydration state of the membrane and electrodes, so that operating conditions can be adjusted to optimise water management. Individual electrode potentials and impedances are even more important in methanol cells, and can be conveniently measured with the DHE.     

工程监理对施工安全的控制要点及措施

论述监理工程师必须加强施工安全管理,重点叙述施工安全控制要点、要求及措施。     

OSI RM网络层基于通信子网的路由选择算法

本文论述了ＯＳＩ ＲＭ网络层基于通信子网的路由选择算法的若干问题，包括算法的设计原则、原理、实现方法以及关于算法完善性的讨论。     

Copper Oxide Precipitates in NBS Standard Reference Material 482

Copper oxide has been detected in the copper containing alloys of NBS Standard Reference Material (SRM) 482. This occurrence is significant because it represents heterogeneity within a standard reference material that was certified to be homogeneous on a micrometer scale. Oxide occurs as elliptically to spherically shaped precipitates whose size differs with alloy composition. The largest precipitates occur in the Au20-Cu80 alloy and range in size from submicrometer up to 2 μm in diameter. Precipitates are observed using light microscopy, electron microscopy, and secondary ion mass spectrometry (SIMS). SIMS has demonstrated that the precipitates are present within all the SRM 482 wires that contain copper. Only the pure gold wire is precipitate free. Initial results from the analysis of the Au20-Cu80 alloy indicate that the percentage of precipitates is less than 1 % by area. Electron probe microanalysis (EPMA) of large (2 μm) precipitates in this same alloy indicates that precipitates are detectable by EPMA and that their composition differs significantly from the certified alloy composition. The small size and low percentage of these oxide precipitates minimizes the impact that they have upon the intended use of this standard for electron probe microanalysis. Heterogeneity caused by these oxide precipitates may however preclude the use of this standard for automated EPMA analyses and other microanalysis techniques.     

多探头全身计数器探测效率随体模大小的变化及修正

本文介绍利用计算机对全身计数器进行效率刻度的方法，文中计算一个固定多探头全身计数器系统对不同大小体模的探测效率，分析了探测效率随体模长度和体厚因子变化的关系，并给出了对于＾１３７Ｃｓ源，通过修正参考人体模的探测效率而得到不同大小（身长１４５～１８５ｃｍ体，重４５～８７ｋｇ）体模探测器效率的近似公式。     

连续系统的模型参考自适应辨识新方法

１引言文［１］提出了将待辨系统以被控对象的形式嵌入到Ｎａｒｅｎｄｒａ等［２］的自适应控制结构中去的连续系统辨识方案，解决了传统的模型参考自适应辨识方法不能处理待辨系统不稳定或不具备良好暂态品质的问题．但它不能处理非最小相位系统，而且对于相对阶大于１并且传递函数分子阶次大于０的系统，因需要进行矩阵求逆而使运算复杂，精度降低．本文在文［１］的基础上，提出了将待辨系统与一个适当选择的相对阶为１的系统并联后作为被控对象嵌入到模型参考自适应控制系统（ＭＲＡＣＳ）中去的辨识方案，解决了上述问题。２辨识方案考…     

X线胸透受检者的体表照射量分布及评价

本文应用热释光剂量元件测定了苏州市第一人民医院９０人次Ｘ线胸透时受检者体表照射量的分布。测量结果表明：相应于第６胸椎处的照射量最大，以此处为参考点照射量向四周逐渐下降。每次胸透受检者最大入口体表照射量的平均值和单次测量标准差分别为２．１５×１０￣（－４）和１．３４×１０￣（－４）Ｃ·ｋｇ￣（－１），每次胸透所致平均有效剂量当量为０．２２ｍＳｖ。     

CIM与工业自动化总体技术：它的目标,方法和实践

本文概述了近年国际上兴起的CIM与国内的工业自动化总体技术,阐明了其出现背景,以及它的目标、方法、参考模型和有关实践情况,在CIM参考模型和体系结构中,叙述了西欧ESPRIT的CIM/OSA模型、美国普渡大学的企业参考体系结构与CIM模型,并简述了它们在建立综合自动化系统中的主要思路。     

网架挠度自动测试系统

本文介绍了一种新型的网架挠度自动测试系统。作者采用电感调频式位移传感器和单片微型计算机组成数据检测和处理系统,研制了刚性和柔性两种参考连接体系,从而实现了网架挠度测试数字化和自动化。该系统具有通道多、测量范围大、精度高、工作可靠、设备轻巧、使用简便等优点,已通过6项工程应用,表明效果明显。