剂量率对聚四氟乙烯辐射裂解的影响

本文研究了在以电子加速器的电子射线为辐射源时,剂量率对PTFE辐射裂解的影响。在剂量相同的条件下,剂量率从1.44×10~4 rad/s增至5.75×10~4 rad/s,裂解效率提高3.3倍。剂量率和各断裂参数(单位剂量裂解度a_0,G(s)值等)均成线性关系。当裂解度一定时,剂量率与剂量成反变关系。     

广西某矿区托帕石的宝石学特征

广西某矿区的脉石矿物——黄玉分三个世代,其中第三世代的黄玉晶体无色透明,重量大于0.9克拉,瑕疵不明显,密度(3.50)、硬度(7.8430)和折射率(1.6330)等特征均达宝石级,经系统研究测试,可以命名为托帕石(Topaz)。     

STM tunneling spectroscopy on high Tc superconductors

STM tunneling spectroscopy has been performed on the bulk single crystals of BiSrCaCuO (BSCCO) and the epitaxial thin films of YBaCuO (YBCO) at cryogenic temperatures. The STM images and tunneling spectra observed on the (001) surfaces can be classified into three cases; 1) Atomic image is visible. However, the tunneling spectrum shows semiconducting or smeared superconducting gap structures, depending on the tip-sample distance. 2) Clear atomic image can not be obtained. But, the tunneling spectrum shows flat bottom region with quite low zero bias conductance. 3) Tunneling spectra demonstrate gapless behavior, independent of the tip-sample separation. These observations support the quasi-2D electronic picture in whichs-wave like 2D superconducting layers are coupled with each other through the Josephson effect.     

贵冶动力中心二期反渗透系统改造

本文阐述对贵冶动力车间二期反渗透进行改造的成功实践 ,主要从反渗透系统设计、反渗透系统中容易出现的问题及解决方法等进行介绍。     

Optimum thermoeconomic and thermodynamic performance characteristics of an irreversible three-heat-source heat pump

The coefficient of performance and specific heating load of an irreversible three-heat-source heat pump are given by using a general cycle model affected by the finite-rate heat transfer, heat leak and internal irreversibility of the cyclic working fluid. The heat pumping load divided by the total cost per unit time is taken as a new objective function and used to investigate the performance of the heat pump. The thermoeconomic and thermodynamic performance characteristics of the heat pump are discussed in detail. Some important performance parameters such as the thermoeconomic objective function and coefficient of performance are optimized. The optimally operating regions of the heat pump and the bounds of several performance parameters are determined. Finally, it is pointed out that the Carnot heat pump may be taken as a special case of a three-heat-source heat pump and consequently its optimal performance can be directly derived from the results obtained here.     

论工艺参数对烧结产质量的影响及分析

本文论述了正确认识烧结工艺参数对搞好烧结生产的意义，介绍了烧结工艺参数其及相互关系，详述了烧结主要工艺参数对其产质量的影响，提出了烧结工艺参数认识的几点结论性意见。     

改进的GMDH方法及其在参数预报中的应用

本文在综合了ＧＭＤＨ方法中几种有效的改进算法的基础上，进一步研究了变量预选及部分表达式的构成问题，采用最优化方法确定变量最佳组成式并进行变量筛选，由此得到精度更高、稳定性较好的模型，将其应用于聚丙烯熔指数的预报，仿真结果令人满意。     

基于Legendre多项式的随机连续系统的Markov参数估计

本文在讨论连续Ｗｉｓｅｎｒ过程的Ｌｅｇｅｎｄｒｅ多项式逼近值的相关性和Ｗｉｅｎｅｒ过程扰动下连续线性系统基于该正交多项的最小二乘估计有偏性后，提出了无偏一致的且数估计误差方差最小的Ｍａｒｋｏｖ估计（最小方差估计）算法，并给出本文方法的仿真结果。     

Valid parameter range analyses for chemical reaction kinetic models

The present work quantifies the relations between the structure of a chemical reaction kinetic model, its valid parameter range, and the truncation error tolerance of the model. General methods are presented to solve the three important problems of valid parameter range analysis: (1) identification of the valid parameter range of a kinetic model, (2) estimation of the error tolerance required when applying a kinetic model over a specified parameter range, and (3) improvement of existing model generation algorithms to construct more robust models. Finally, the relationship between a model's structure, its valid parameter range, and the truncation error tolerance are illustrated by the flexibility-tolerance-model graph. The new methods are applied to pyrolysis of methane/ethane mixtures.     

Pultruded fibre reinforced polyurethane composites II. Effect of processing parameters on mechanical and thermal properties

This paper presents a novel process for the fabrication of pultruded polyurethane (PU) composites. The effects of the processing parameters on the mechanical properties (flexural strength and flexural modulus, etc.) and thermal properties (HDT) of the fibre reinforced PU composites by pultrusion have been studied. The processing parameters investigated include pulling rate (in-line speed), die temperature, filler type and content, and post-cure time and temperature. Results show that the composites possessed various optimum pulling rates at different die temperatures. On the basis of the DSC diagram, the swelling ratio, the mechanical properties and the thermal properties of composites, the optimum die temperature can be determined. It is found that the mechanical and thermal properties increase with filler content for various types of filler. The mechanical and thermal properties increase at a suitable post-cure temperature and time. Furthermore, the properties which decreased due to the degradation of composite materials for a long post-cure time will be discussed.