汽轮机初始湿蒸汽级的不平衡两相流

本文提出一种采用自发凝结成核理论进行汽轮机初始湿蒸汽级圆柱面轴对称不平衡湿蒸汽流动数值计算方法。以一台国产汽轮机的初始湿蒸汽级为例,得到不同半径上不平衡流气动热力参数的变化规律;分析了该级中不平衡两相流动的特点及其对级特性的影响:指出了改进湿蒸汽透平级工程热力计算方法的途径。     

汽油机燃烧过程的一维数值模拟

本文建立了汽油机燃烧过程的一维数值模型。在模型中,假设火焰前锋面为柱形,它从火花塞中心向气缸壁面传播;各计算量均作为曲轴转角和燃烧室径向位置的函数;系统中的瞬时反应率遵守双分子碰撞的 Arrhenius 关系;应用有限差分法求解偏微分方程组。实例计算表明,示功图的计算结果与试验结果比较符合。使用这个模拟方法可以计算气缸内温度场和浓度场的径向变化,并能预测火花塞的径向位置对燃烧过程的影响。     

广东省鳞伞属的种类记述

本文根据Smith和Hesler(1968)的分类系统,对近年来发现于广东地区的16种鳞伞属种类作一记述。其中5个新种(另文发表),9个国内新纪录。     

Trace metals in soil, dust, and tree leaves of the urban environment, Guangzhou, China

Metals have been constantly introduced to urban environments via various point and non-point sources of pollution,and have contaminated different urban compartments(sample types).However,most research projects have focused on a single environmental compartment to characterize urban metal contamination.In the present study,an integrated sampling program that includes surface soils,different size fractions of soil and road dust(<50 μm,50-100 μm,100-250 μm,and 250-1000 μm),tree leaves,and grasses,was conducted in a typical urban area of Guangzhou,China.The aim of the study was to investigate the interrelationships among the metal pollutants in these samples.The concentrations of trace metals varied greatly among different sample types,and their distribution was generally in the following order:road dust > soil dust ≥ surface soils ≈ top soils > grasses ≥ tree leaves.As for the relationships among the trace metals,different combinations were seen among the sample types,indicating different loadings of trace metals in the sampling medium.Significant correlations of metal concentrations were found between tree leaves and the smallest(<50 μm) fraction of road dust,and between soil dust(50-100 μm) and surface soils,suggesting that trace metals in these samples may influence each other.     

A parallel algorithm for statistical-fairness-based spectrum allocation of cognitive radios

A parallel algorithm for statistical-fairness-based spectrum allocation of cognitive radios is proposed in this paper. The key idea of the algorithm is to pursue the maximum total spectrum utilization of the system by adopting a parallel technique in every spectrum allocation, and to ensure the statistical fairness rule by deploying a particular scheme during a series of allocations. The simulation results show that the proposed algorithm not only achieves a fairer and more efficient allocation of spectrum resources, but also has much shorter allocation duration than the color sensitive graph coloring (CSGC) algorithm.     

如何推进企业信息化的建设和发展

阐述了信息化的概念和意义,分析了山西省企业信息系统开发水平落后的原因,主要从管理、投资、人员培训与组织管理、网络建设等几方面提出企业MIS总体开发的一些实施策略.     

下一代超媒体文件传输协议（HTTP—NG）的结构分析与研究

对当前ＨＴＴＰ存在的问题和Ｗｅｂ应用的需求进行了分析，并给出了一下代超媒体传输协议ＨＴＴＰ－ＮＧ的结构模式及其各层的功能，昔在改善目前ＨＴＴＰ／１．ｘ的性能，以适应Ｗｅｂ应用迅速发展的需要。     

KSHT-I型三辊穿轧机快速回退控制仪的研制

本文主要介绍了“ＫＳＨＴ－Ｉ型三辊穿轧机快速回退控制仪”，这个简单而实用单片机系统的基本组成、软件设计、研制过程和现场实际中产生的问题以及针对这些问题所采用的有效措施。实践证明快速回退控制仪和所采用的压力传感器及其信号放大装置实用可行。     

迭加原理的数学基础及其在物理学中的应用

迭加原理是线性系统具有的一个重要性质，在物理学中有着广泛的应用，为人们在许多领域的研究提供了简便的方法，但它不是普遍成立的原理。本文从数学物理的角度讨论了迭加原理的数学基础，概述了迭加原理在物理学中的应用，并指出迭加原理的适用范围。     

示波分析新进展

对１９９０年以来示波分析新技术的发展进行了评论；对示波分析在环境监测、药物分析以及治金分析等方面的实际 进行了阐述。