利用黄河泥沙加固下游大堤

黄河是一条举世闻名的多泥沙河流，善淤、善决、善徒给沿河人民带来对过深重灾难，防洪问题一直是国家的心腹之患。泥沙问题是黄河防洪问题的症结所在。在总结固大堤经验的基础，进行挖河疏浚，淤筑“相对地下河”，已作为黄河治理的一项重大决策付诸实施。     

The relative permeability of concrete using nitrogen gas

A modified version of a test, originally proposed by BRE (UK), was used to assess relative permeability to nitrogen gas of concretes cured in various ways. Three simple parameters from test plots clearly showed the effects of duration of water curing, followed by drying to constant mass at 50°C; test specimen moisture content was dominant and drying at 105°C reduced differences between concretes of very different quality. Convincing evidence was not found of differences between upper and lower ‘halves’ of cylinders nor between cast and cored ones.     

带隔板底水油藏油井临界产量计算公式

本给出了带隔板底水油藏油井的监界产量计算公式，它适用于所有带隔板底水油藏的油井。     

THE STATISTICAL DISTRIBUTION OF EXTREME VALUES OF WAVE-CURRENT FORCES ACTING ON SLENDER CIRCULAR CYLINDER IN IRREGULAR WAVES

Based on model test,the statistical distribution of extreme values of wave-current in-line forces acting on vertical circular cylinder is analyzed in this paper.It is shownthat the results calculated by the simplified method,proposed by authors,agree well with the testdata;Weibull distribution is also adoptable in the region of high KC number, and the shapeparameter a and scale parameter β are related well with KC number respectively.     

带类型λ—演算

一、引言补演算是一个用函数描述计算的形式理论体系[1J,它由许多计算模型所组成。文〔1〕指出,应用认-演算比纯粹补演算更接近程序语言.但是由于内建函子和常数的引入常会发生一些问题,例如.常数O和函子+在机器中同样看待     

Efficient Parallel Algorithms for Some Graph Theory Problems

In this paper,a sequential algorithm computing the aww vertex pair distance matrix D and the path matrix Pis given.On a PRAM EREW model with p,1≤p≤n^2,processors,a parallel version of the sequential algorithm is shown.This method can also be used to get a parallel algorithm to compute transitive closure array A^* of an undirected graph.The time complexity of the parallel algorithm is O(n^3/p).If D,P and A^* are known,it is shown that the problems to find all connected components,to compute the diameter of an undirected graph,to determine the center of a directed graph and to search for a directed cycle with the minimum(maximum)length in a directed graph can all be solved in O(n^2/p logp)time.     

合成氨制气中的以水代汽新工艺

提出了应用油水融合技术在合成氨部分氧化法制气中以水代汽的工艺途径，并分析了其效果和意义。     

广东省伴生放射性矿资源利用过程辐射水平调查

为加强伴生放射性矿物资源开发利过程中放射性环境管理 ,防治放射性污染 ,对广东省几个大型伴生矿(包括稀土矿、钽铌矿和铅锌矿 )资源利用 (开采、冶炼、加工 )过程中天然放射性核素的污染现状进行了调查。调查结果表明 :稀土矿中独居石 ,天然放射性核素含量最高 ,2 3 8U、2 3 2 Th、2 2 6Ra的含量分别为 3.5 1× 1 0 4、1 .74× 1 0 5、4 .8×1 0 4Bq/kg,其冶炼废渣中核素的含量分别为 5 .1 0× 1 0 5、6 .38× 1 0 6、1 .5 2× 1 0 6Bq/kg。稀土选冶厂周围陆地环境 γ射线的空气吸收剂量率比一般地区的高。     

Processing of Yttria-Alumina Coated Silicon Nitride Slips by Slip Casting

Si₃N₄powders coated with 6 wt% Y₂O₃and 4 wt% Al₂O₃were prepared by coprecipitation. The resulting powders were dispersed in water at different pH values and with addition of various amounts of ammonium polyacrylate (NH₄PA) to produce 32 vol% slips. The influence of the amount of NH₄PA solution added and pH on the rheological properties of 32 vol% coated Si₃N₄slips were studied. In addition, the sintered density of cast samples was determined and related to the degree of slip dispersion. The adsorption of the NH₄PA on the coated particle surface was rather high and the surface became saturated near 0.86 mg/m²at pH 9.2. High NH₄PA concentrations (1.7–3 wt%) were necessary to obtain well dispersed 32 vol% coated Si₃N₄slips at pH 9.2. The best stabilization was obtained with the addition of 2.3 wt% NH₄PA; in this condition, the viscosity reached a minimum value of 35 mPa.s at 100 s^–1. The slip viscosity increased with increasing pH from 9.2 to 10.2. Slips with low viscosities gave a more dense packing of cast samples and consequently higher sintered density values.     

关于后张预应力混凝土结构优化设计的几个问题

结合UP软件编程实践，本文对后张预应力混凝土结构计算程序中引入优化功能的意义进行了论述，提出了预应力筋与普通钢筋之间的最优搭配关系，优化原点概念及相关影响因素，列出了优化计算程序所应涉及的基本计算内容，并对当前后张预应力混凝土结构设计中的一些观点提出了不同意见。