地铁火灾场景设计的初步研究

现阶段地铁火灾研究的主要工具是计算机模拟,而模拟计算结果准确与否很大程度上取决于火灾场景选取得是否恰当.本文通过对地铁站内的可燃物状况和已发生地铁火灾情况的仔细调查与分析,设定出了几种典型的地铁火灾场景,为地铁火灾模拟计算提供了依据.     

乐安江沉积物酸碱特性及其对重金属释放特性的影响

本文对乐安江沉积物样品的金属总量、酸碱特性进行了测定和不同pH条件下金属的释放实验.结果表明,乐安江沉积物中Cu,Pb,Zn,Cd和As的浓度均高于一般水体沉积物的本底值.从重金属的移动性分析,存在沉积物重金属对水体产生二次污染的可能.沉积物所含重金属随pH变化产生的金属释放顺序是Zn>Cu>Cd.Pb.     

CHANGE IN LAKE TROPHIC STATE AND INTERNAL PHOSPHORUS RELEASE AFTER ALUMINUM SULFATE APPLICATION1

ABSTRACT: Recovery of eutrophic lakes after nutrient diversion may be delayed if the lake experiences significant internal phosphorus (p) loading to the water column. A maximum dose of aluminum sulfate, defined herein, was applied to the anaerobic sediments of the hypolimnia of two dimictic Ohio lakes following septic tank diversion, with the objective of attaining long term control of the release of phosphorus to the water column from these sediments. The results were compared to a similar, downstream, untreated lake. Total phosphorus concentration declined sharply after treatment and has remained so through 1980 for both lakes, a period of 5 and 6 years of control, respectively. Internal P loading from anaerobic, hypolimnetic sediments was partially controlled by the treatment but there are other important sources, perhaps in the littoral zone, in these lakes. Algal biomass is Smaller and water transparency has increased. Both lakes became mesotrophic after treatment, as described by the Carlson (1977) trophic state index, and remain in that improved condition to date. No deleterious side effects were observed, although one lake experienced a significant decrease in diversity of planktonic microcrustacea and a lakeward extension of the macrophyte community. This method appears to be an effective and lasting means of accelerating the recovery of a eutrophic lake following nutrient diversion.     

设计火灾时火灾热释放速率曲线的确定

在运用火灾计算机模型进行建筑物性能化消防设计与评估时,确定合理、切合实际的火灾的热释放速率曲线非常重要。基于当前国内外的研究现状,本文提出了几种符合当前技术水平且实用的确定火灾热释放速率曲线的方法,对于每种分析计算方法及其适用条件进行了详细阐述,并给出了相关的计算实例。     

Vent sizing for gas-generating runaway reactions

Exothermic runaway reactions that generate non-condensible gas as the temperature increases, as is typical of decompositions for example, can reach extremely high rates of pressure rise necessitating emergency relief of the process vessel containing the reactant. Sizing of a relief device using presently recommended methods (e.g. DIERS) frequently leads to extremely large and expensive vents. This paper presents a methodology that leads to a simple but much improved method for vent sizing, fully allowing for two-phase release of the gas—liquid mixture. A number of examples are presented which lead to interesting conclusions about the influence of plant variables.     

A STOCHASTIC DYNAMIC PROGRAMMING BASED APPROACH TO THE OPERATION OF A MULTI-RESERVOIR SYSTEM1

ABSTRACT: An heuristic iterative technique based upon stochastic dynamic programming is presented for the analysis of the operation of a three reservoir ‘Y’ shaped hydroelectric system. The technique is initiated using historical inflow data for the downstream reservoir. At each iteration the optimal policies for the downstream hydroelectric generating unit are used to provide relative weightings or targets for operation of upstream reservoirs. New input inflows to the downstream reservoir are then obtained by running the historical streamflow record through the optimal policies for the upstream reservoirs. These flows are then used to develop a new operating policy for the downstream reservoir and hence new targets for the upstream reservoirs. The process is continued until the operating policies for each reservoir provide the same overall system benefit for two successive iterations. Results obtained from the procedure are compared to the results obtained by historical operation of the system. The procedure is shown to develop operating policies which give benefits which are as close to the historical benefits as can be expected given the choice of the number of storage state variables.     

高效液膜分离富集测定微量铜

应用高效乳状液膜技术分离、富集水和土壤样品中微量铜（Ⅱ）．研究了流动载体（Ｐ２０４）、表面活性剂（ＳＰａｎ８０）、膜的增强剂（液体石蜡）、膜溶剂（煤油）和内相解吸剂（２．５ｍｏｌ／ＬＨ２ＳＯ４）等液膜体系，对分离富集微量铜（Ⅱ）的影响．确定了Ｓｐａｎ８０—Ｐ２０４─液体石蜡─煤油─Ｈ２ＳＯ４高效液膜体系的最佳组成和最适宜的实验条件．富集后的溶液用１－（２－吡啶偶氮）－２－萘酚（ＰＡＮ）分光光度法测定铜（Ⅱ）．用本法富集水和土壤中微铜（Ⅱ）．回收率在９９％以上。应用于测定水和土壤中的微量铜．相对标准偏差为１．２％～４．５％。     

东海特定海区沉积物-水界面附近P释放的实验研究

以采自长江口外东海表层沉积物为对象，对不同类型的沉积物在模拟海水环境中进行了释P实验。研究表明，在静态条件下，沉积物释P量的高点出现在摇晃后10min左右，大约3h后基本趋于平衡。释P动力学可用Elovich公式与双常数速率公式进行拟合。最大释P量与沉积物的组成密切相关，以粉砂、粘土为主的沉积物释P量高，而砂质为主者释P量低。在释P实验中，铁磷(Fe-P)最为活跃，释放比例最高，其次是吸附态磷(Ad-P)和有机态磷(OP)。它们均属于生物可获得P的范畴。实验结果表明，在合适的水动力条件下，沉积物中的P可以迅速释放到水体．并影响水体的营养状杰和初级生产力。     

用突变理论分析矿山冒落型地震机理

矿山冒落型地震是一种破坏性最为严重的地质灾害之一。研究其成因机理 ,对矿山安全生产具有重大的现实意义。笔者根据矿山冒落型地震的特征 ,应用突变理论和能量守恒原理 ,建立了一个简单的力学模型 ,提出由地下开采引起采空区顶板突然破坏和冒落—释放能量—诱发地震的观点 ,并结合现场实例进行分析 ,得到顶板冒落和所释放出来的能量表达式 ,这为研究矿山冒落型地震成因机理提供了一种新的方法。     

冒落型矿震成因机理的研究

冒落型矿震属于塌陷地震的范畴 ,其形成和演化受到区内自然因素和人为因素的作用。笔者研究了顶板冒落的前兆特征、发展过程、运动形式和致崩原因 ,探讨了冒落型矿震的成因机理 ,提出了由于地下开采引起采空区顶板冒落 ,释放能量 ,诱发矿震的观点。