联合上限法和主应力法确定模具表面压力分布的研究(Ⅰ)

提出了一种联合上限法(Upper Bound Method)和主应力法(Slab Method)确定模具与金属接触表面压力分布的方法.这是一种基于利用上限法确定金属流动和变形区,然后根据主应力法原理计算接触面压力分布的方法,简称UBM/SM联合法.这种方法较其它方法简便,而且能给出计算压力分布的解析式.本文阐述该法的基本原理,并用它计算杯形件反挤时凸凹模表面的压力分布.     

A conceptual approach to selection of a control measure for residual chlorine discharge in Kuwait bay

It is estimated that some 17 metric tons of residual oxidants (chlorine) are discharged into the enclosed coastal seawater of Kuwait on a daily basis from power-desalination plants alone. Alarmed by the unlimited number of reported cases of damage to marine aquatic systems due to chlorine discharge around the world, several alternatives were proposed to control such a massive discharge of residual oxidant into seawaters. Most of the proposed alternatives lacked the basic criteria necessary for their evaluation, justification, and then selection. The objective of this article is to provide a conceptual approach that can be used to select a control measure for residual oxidant discharge in Kuwait coastal seawaters. This approach is based on state-of-the-art knowledge and the unique operational and environmental factors involved. A matrix system was designed whereby the cost of residual chlorine control alternative, its effectiveness, and environmental and public health impact, performance, and reliability in Kuwait can be compared and evaluated. The selection approach considered currently operating power plants in terms of their engineering design and material (cast iron or steel condensers), current operational conditions, operator's perception, acceptability, and projected problems associated with the environmental management of proposed modifications. The proposed approach revealed that in Kuwait, conventinal chlorination was marginally superseded only by chlorination/dechlorination using SO₂ and operation alteration using process optimization. The overall cost-effective assessment matrix classified other alternatives as worse than chlorination by various degrees. Ozone and UV were found to be the worst and the least desirable alternatives for biofouling control of seawater in Kuwait. In light of the available information on the consequences of the Gulf War on the marine environment, and the potential formation of additional halogenated organic compounds through the reaction of residual chlorine with the released petroleum hydrocarbons, it is essential to control residual chlorine discharged into the nearshore environment of Kuwait.     

生态城市动态指标体系的构建与分析

阐述了生态城市的内涵,并从城市的经济系统、社会系统、自然生态系统三个方面构建了生态城市的指标体系。 体系还体现了不同城市的地域特点,以及城市复合生态系统的动态平衡。最后以苏州市为例。分析了其生态化进程。     

联合上限法和主应力法(UBM/SM法)确定模具表面压力分布的研究(Ⅱ)

本文根据前文所提联合上限法和主应力法确定模具表面压力分布的基础原理,计算了圆柱坯料正挤压和十字头锻件镦挤时模具表面的压力分布,所得结果与测定值很吻合,进一步证明了UBM/SM法实际应用的可靠性.     

关于塑性应变比的测定

此文用直接法和间接法研究了δ值和计算方法对γ值的影响。发现γ值基本上与δ无关。δ只影响其测量精度,δ愈大愈有利于提高γ的测量精度。计算方法对γ值的影响只在δ值较小时。随δ增大,计算方法的影响逐步消除。     

气相色谱-质谱法测定土壤中的汽油及其组分含量

对土壤中的汽油,采用外标法,经吹扫捕吸仪浓缩后,用气相色谱-质谱法分析定量。同时,用峰面积归一化法,可以测定土壤中汽油的组分含量。     

冶金企业无组织排放颗粒物影响评价

以上海市某冶金企业为例,该厂有正常运行的冶炼炉13座,每年向大气中排放大量颗粒污染物.基于高斯倾斜烟羽模式,整理了2003年上海市全年的气象资料,运用气象概率矩阵法计算了该厂直排点源及无组织面源排放颗粒物的影响,得出了厂区内无组织排放颗粒物落地浓度等值线图.计算结果表明,厂区内颗粒物污染主要来自无组织面源,污染集中在厂区中心的污染源附近;直排点源对环境的影响较小,污染主要集中在下风向.     

Determinants of parental effort: a behavioural study in the Eurasian kestrel,Falco tinnunculus

We recorded behaviour of kestrels (Falco tinnunculus) in western Finland during the courtship (1988–1992), incubation (1989–1991), early nestling (age of young 1–2 weeks, 1989–1992) and late nestling stages (3–4 weeks, 1989–1991) to examine determinants of their parental effort (PE). In males, PE was estimated as the hunting effort (the proportion of budget time spent in flight-hunting) and in females as the food provisioning rate (number of prey items delivered to the nest per hour). The following predictions derived from the parental investment theory were examined. (1) Parents rearing large clutches and broods should invest more in breeding than do parents rearing small clutches and broods. The hunting effort of parents did not increase with clutch or brood size, but males tending large broods had a higher prey delivery rate than males tending small broods (Figs 1–2). (2) PE of parents should increase in the course of the breeding season. In males, this was true only between the incubation and early nestling phases (Fig. 3). (3) The early pairs should invest more in breeding than late ones. This tended to be true during the early (for males) and late nestling phases (for females) (Fig. 4). (4) There should be a negative correlation between PE of mates within pairs, but no evidence for such adjustment was found (Fig. 5). (5) Females mated with bright-coloured attractive males should show higher PE than females mated with dull-coloured males but our results were inconsistent with this prediction. We conclude that PE decisions of kestrels are mainly based on cost-benefit estimates of residual reproductive value, rather than on current investment indicators, like clutch or brood size. This might be beneficial in environments with highly variable survival prospects of offspring caused by pronounced among-year variation in abundance of the main food (microtine rodents). The results also show that hypotheses explaining variation in PE in the short term are not necessarily valid for long-term PE, e.g. tending clutches or broods, which also reflects the demands of female and young.     

生物膜法与活性污泥法

通过两种工艺不同特点的对比，指出了生物膜法工艺的根本特性，说明该工艺是有机污水治理的江佳选择，是炼油污水处理工艺的最佳选择．另对“无剩余污泥”提出了不同看法．     

应用电化学方法处理印染废水

本文简要介绍了电化方法的原理、特点及其在印染废水处理中的应用．