Application of a multi-step computation scheme to an intratidal estuarine water quality model

A computation scheme, which involves multi-step computation of the decoupled mass-balance equations in water quality models, was proposed by Park and Kuo (1996. Water Res. 30, 2255–2264). Using a simple hypothetical model, they explained the concept and demonstrated the accuracy and computational efficiency of the multi-step scheme. This paper describes the concept and the implementation of the multi-step computation scheme in a more generalized format for both intratidal and intertidal estuarine water quality models. The scheme is applied to a prototype estuary using a laterally-integrated two-dimensional intratidal model. The computational efficiency of the scheme is demonstrated by comparing the model results using the multi-step scheme with those using the traditional single-step explicit numerical solution of the kinetic processes.     

青藏高原东部亚高山森林草甸植被地理格局的成因探讨

森林和草地在亚高山带的阴阳坡上形成的交错分布现象,呈一弧型分布在青藏高原东部本文在综合分析了造成这种现象的生理生态因素之后,重点从火的作用、放牧作用和历史时期人类活动的影响等方面,讨论了青藏高原东部亚高山带植被地理格局的形成原因结果表明,自然生态因素和人类活动的影响在植被地理格局的形成过程中起着同等重要的作用,其中火灾的作用以及气候变化造成的人口迁移压力作用十分明显．在这一弧形区域内,林线以下的亚高山灌丛或草甸多属次生类型,人类有目的的烧荒和长期放牧阻滞了植被的顺向演替,维持了亚高山（灌丛）草甸的偏途顶级状态．     

Water Environmental Degradation of the Heihe River Basin in Arid Northwestern China

Water environmental degradation is a major issue in the Heihe River Basin belonging to the inland river basin of temperate arid zone in northwestern China. Mankind’s activities, such as dense population and heavy dependence on irrigated agriculture, place immense pressure on available and limited water resources during the last century, especially the recent five decades. An investigation on the water environmental degradation in the Heihe River Basin and analysis of its causation were conducted. The results indicated that water environmental changes in the whole basin were tremendous mostly in the middle reaches, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Some new forms of management based on traditional and scientific knowledge must be introduced to solve problems of water environmental degradation in the Heihe River Basin.     

MOVEMENT BEHAVIOUR OF MEDAKA (Oryzias latipes) IN RESPONSE TO SUBLETHAL TREATMENTS OF DIAZINON AND CHOLINESTERASE ACTIVITY IN SEMI-NATURAL CONDITIONS

Behavioural changes of medaka (Oryzias latipes) treated with an anticholinesterase insecticide, diazinon (0.1 mg L^{- 1}), were continuously observed for 4 days in semi-natural conditions. Although variations occurred in individual specimens, the movement tracks appeared differently with typical short-range movement with irregular turns and shaking after the treatments. Eight movement patterns frequently observed before and after the treatments were selected, and the variables characterising the movement patterns were compared quantitatively. The variables were clearly differentiated when the movement patterns were correspondingly matched before and after the treatments (e.g., vertical movements, horizontal movements, etc). Meander and stop duration were highly different among the selected movement patterns. Additionally, different degree of toxic response behaviours could also be detected by quantitative characterisation of the variables. Response behaviour was confirmed with toxicological experiments that show the decrease in the acetylcholine esterase activity in the head and body of specimens. Quantitative investigations on the variables of the movement tracks suggested the usefulness of response behaviour as a monitoring tool for environmental assessment.     

挥发性有机化合物催化氧化催化剂的制备和性能研究

研制出用于催化氧化废气中挥发性有机化合物（ＶＯＣ）的非贵金属氧化物催化剂,在固定床上,处理含醋酸丁酯的模拟气,考察了空速、浓度等因素对催化剂活性的影响及催化剂的耐热性能,当空速为５０００ｈ＾－１,进气温度为２２０℃、醋酸丁酯质量浓度为２．４～５．８ｇ／ｍ＾２时,醋酸丁酯的去除率〉９８％,而且该催化剂人具有较高的热稳定性。     

1999年9月21日台湾7.6级大震预报讨论

介绍了用三性法（周期性,公度性,黄金分割性）对１９９９年９月２１日台湾７．６级大震的三要素预报,并用构造分段公式,“静中动判据”补充作了讨论。鉴于短监预报的重要,我们还用样暴倍九律,即预滑－磁暴－天气韵律模式对９．２１大震的发震日期的预报作了讨论。     

纳豆激酶原核表达载体的构建及其活性鉴定

利用引物搭桥的方法,经PCR扩增,获得了纳豆激酶成熟肽基因(NK),从而构建了大肠杆菌表达质粒NK/pTWIN1,NK/PET32a及NK/PML-c2x,经分别转化宿主菌ER2566,BL21和ER2566,获得了转纳豆激酶基因重组菌.结果表明,NK/pTWIN1-ER2566和NK/PET32a-BL21的纳豆激酶蛋白表达量较高.本研究选用NK/pTWIN1-ER2566作为表达菌株,对其进行发酵表达.SDS-PAGE显示,目的蛋白约占菌体总蛋白的36%,该蛋白是以包涵体形式存在的.包涵体经收集、蛋白变性及复性,并经过SP Sepharose分离纯化,得到了纯化的纳豆激酶蛋白,琼脂糖-纤维蛋白平板法测出1mg纳豆激酶干粉的溶栓活性相当于600u尿激酶.本文从基因工程角度研究纳豆激酶基因的克隆、表达及纯化,为利用基因工程菌生产纳豆激酶奠定了基础.图5表1参11     

过氧化氢酶活性及活性抑制的测定

广泛存在微生物及动植物体内的过氧化氢酶已应用于生态毒理及生态化学的研究领域，本文主要介绍了通过肝过氧化氢酶活性抑制的测定，来估价受试化学品对水生生物急性及亚急性效应的方法。     

有机溶剂,表面活性剂及NaCl对对二氯苯在水中活度系数的影响

本文利用气相色谱法测定了对二氯苯在不同组成的水溶液体系中的活度系数,其中包括二组份与三组份共溶剂体系、表面活性剂-水体系与NaCl-水体系。实验结果表明:对二氯苯在二组份和三组份共溶剂体系中的活度系数的对数值与各组份的体积分数之间有线性加和关系;表面活性剂在达到临界胶束浓度以上时,可显著降低对二氯苯在水中的活度系数;对二氯苯在NaCl水溶液中的活度系数与NaCI的含量之间成正比关系。作者还利用UNIFAC法估算了对二氯苯在各种共溶剂体系中的活度系数,所得估算值与测定值相接近。     

汞和硒对剑尾鱼Na+/K+-ATPase活性的影响

应用浸浴法研究汞(Hg)对剑尾鱼(XiphophorushelleriHeckel)鳃和肝脏Na /K ATPase活性的影响以及硒(Se)对机体Na /K ATPase汞中毒的保护作用.结果表明,Hg和Se对剑尾鱼96hLC50分别为0.84mg/L和6.64mg/L.Hg对剑尾鱼鳃和肝脏Na /K ATPase活性的影响相似,与对照组相比,处理d1时低浓度Hg组鳃和肝脏ATPase活性没有明显变化(P>0.05),但高浓度Hg组ATPase活性变化显著(P<0.05),至d3和d5时,酶活性均极显著下降(P<0.01),鱼鳃和肝脏酶活性分别下降32%和60%,表明Hg处理对鳃和肝脏Na /K ATPase活性具有抑制作用.单独加Se组鱼鳃和肝脏Na /K ATPase活性在d3和d5显著提高(P<0.01).Hg Se组与Hg组相比,酶活性有明显差异(P<0.05或P<0.01),Se对剑尾鱼Hg中毒具有保护作用.剑尾鱼鳃和肝细胞Na /K ATPase活性可作为对水环境汞污染效应环境风险评价(ERA)的有效生物学标记.表2参16