大陆的起源及其早期增长速率

<正> 引言毫无疑问,大陆的成因和增长问题,在过去、现在和将来都是地质学家十分感兴趣和有争论的课题。地球化学和地球物理资料提供了大陆和地幔演化的大量边界条件。然而,其中的大多数边界条件都不是唯一的。有些边界条件似乎是相互矛盾的。特别是Nd和Pb同位     

处理工业废水的中试装置

每一个化学工程师或环境工程师都了解中试装置在新工艺的开发和应用中的历史作用及重要性。在70年代初期进行的许多废水处理中试研究为系统设计提供了设计基础,这些系统满足了美国环境保护局(EPA)颁布的最佳实用技术(BPT)排放限制。     

美国中西部地区环境保护观感

美国的东海岸和西海岸代表着当今全美高度发展的现代化的科技经济，中西部地区则代表着美国最本质和最核心的自然生态环境和最具雄厚生产潜力的农业经济。美国中西部地区东起密西西比河，西至著右的洛基山脉。美国中部地区是重要的农业和乳富业产地。这里不但气候适宜、雨量充沛、日照丰富，而且地势平坦，土质肥沃。这里根据不同作物生长所需的环境条件而划定了许多种植带，使农业生产获得充分发展和稳定的产量。自北向南，有小麦、玉米、大豆、棉花、稻米种植带，以及最北部五大湖地区以种植青贮玉米和牧草为主的大面积的乳富带。这一地区…     

Past changes in the abundance of diatoms as inferred from a sediment core from Hebe Haven, Saikung, Hong Kong

１　Ｉｎｔｒｏｄｕｃｔｉｏｎ１－１　ＤｉａｔｏｍｓＤｉａｔｏｍｓ（ＣｌａｓｓＢａｃｉｌｌａｒｉｏｐｈｙｃｅａｅ）ａｒｅｃｏｍｍｏｎａｎｄｗｉｄｅｌｙｄｉｓｔｒｉｂｕｔｅｄｉｎｂｏｔｈｆｒｅｓｈａｎｄｍａｒｉｎｅｗａｔｅｒｓ（Ｍｏｓｅｒ，１９９６）．ＴｈｅｓｅｍｉｃｒｏｓｃｏｐｉｃｕｎｉｃｅｌｌｕｌａｒｐｌａｎｔｓｆｉｘａｍａｊｏｒｐｏｒｔｉｏｎｏｆｔｈｅＥａｒｔｈ○ｓｃａｒｂｏｎ，ｇｅｎｅｒａｔｅｏｘｙｇｅｎ，ａｎｄｓｕｐｐｌｙｆｏｏｄｔｏａｎｉｍａｌｓｗｈｉｃｈｆｅｅｄｏｎｔｈｅｍ（Ｄｉｘｉｔ…     

Assessing the impact of air pollution sources in Hong Kong, a densely populated city

As the simple dispersion model tested is not sufficiently accurate to predict the SO2 concentration in complex terrain commonly encountered amongst high rise buildings in Hong Kong, and the lack of comprehensive local wind data at most sites prevents the use of more advanced dispersion model to assess the impact of major air pollutant sources, a receptor model approach is adopted for the apportionment of air pollution sources in Hong Kong. The preliminary results obtained are presented and discussed.     

Comparison of decolorization of reactive microorganisms isolated from various sources

Azo dyes are among the oldest man-made chemicals and they are still widely used in the textile, printing and the food industries.About 10% - 15% of the total dyes used in the industry is released into the environment during the manufacturing and usage. Some dyes and some of their N-substituted aromatic bio-transformation products are toxic and/or carcinogenic and therefore these dyes are considered to beenvironmental pollutants and health hazards. These azo dyes are degraded by physico-chemical and biological methods. Of these, biological methods are considered to be the most economical and efficient. In this work, attempts were made to degrade these dyes aerobically. Theorganisms which were efficient in degrading the following azo dyes-Red RB, Remazol Red, Remazol Blue, Remazol Violet, Remazol Yellow,Golden Yellow, Remazol Orange, Remazol Black- were isolated from three different sources viz., wastewater treatment plant, paper milleffluent treatment plant and tannery was tewater treatment plant. The efficiency of azo dye degradation by mixed cultures from each source wasanalyzed. It was found that mixed cultures from tannery treatment plant worked efficiently in decolorizing Remazol Red, Remazol Orange,Remazol Blue and Remazol Violet, while mixed cultures from the paper mill effluent worked efficiently in decolorizing Red RB, Golden Yellow and Remazol Yellow. The mixed cultures from wastewater treatment plant efficiently decolorized Remazol Black.     

城市大气污染水平变化的近似预测法

<正> 在对城市大气污染水平做长期预测时,通常没有有关污染源的数据资料供精确的计算,这就决定了一般都使用最简单的近似计算法。如果知道排放物总量变化的数据,预测污染物的平均浓度被认定是可行的,这一点也是有条件的。表现为新污染源离市中心的距离变远及污染源高度的增加等城市建设发展趋势,对城市大气状况有巨大的影响。以致,人们在进行近似预测时在某种程度上也予以考虑。     

Influence of form and quantity of chromium on the development and survival of two silkworm (Bombyx mori L.) races

IntroductionThediversityamonginsectlifehistoriesmakesitdifficulttocomparetheeffectofachemical(orfactor)onthedevelopmentoftheseorganisms.Thediversityofbioassaysrangesfromthepopulationleveltothemolecularlevelandfrominvivotoinvitrostudies(Zhang ,1 993 ) .Differentparametershavebeenusedtostudyinsectgrowthinhibitionofmanychemicals.Forexample ,LD50 (thedosewhichcauses50 %mortalityinapopulation)iscommonlyusedtodeterminetheactivityofchemicalsthathaveacutetoxicity .Itcannotbeusedtothosechemicalsthatd…     

Effects of some heavy metals on cell suspension cultures of Catharanthus roseus

ＥｆｆｅｃｔｓｏｆｓｏｍｅｈｅａｖｙｍｅｔａｌｓｏｎｃｅｌｌｓｕｓｐｅｎｓｉｏｎｃｕｌｔｕｒｅｓｏｆＣａｔｈａｒａｎｔｈｕｓｒｏｓｅｕｓＺｈｕＬｉｚｈｏｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＥｎｖｉｒｏｎｍｅｎｔａｌＳｃｉｅｎｃｅ），ＨａｎｇｚｈｏｕＵｎｉｖ...     

贵金属的准确测定

<正> 一、样品分解和分离方法虽然近年来分析仪器有了很大进展,但测定贵金属的基本手段在很大程度上仍是一些经典的化学法。取样和样品分解是准确测定过程中极为重要的一步。因此经典的火试金法在样品分解中仍保持重要地位,氧化熔融、混酸分