砷、汞对植物毒性影响及其迁移富集效应探讨

介绍了自然环境中砷、汞的污染来源与污染现状,探讨了砷、汞对植物生长发育、光合作用和抗氧化能力的影响;为了缓解砷、汞对植物的毒害作用,可以添加新一代植物激素、营养元素和改良剂。分析发现,植物对不同浓度砷和汞的敏感程度并不相同,可利用特定植物的富集作用进行环境修复。当前研究主要集中于植物对砷、汞的吸收和转运生理机制,今后还需要加强对超积累植物分子基础的探索。     

A Variance Estimator for Constrained Estimates of Change in Relative Categorical Frequencies

Consistent estimators of change and state becomes an issue when sample data come from a mix of permanent and temporary observation units. A joint maximum likelihood estimator of state and change creates estimates of state that depend on antecedent viz. posterior survey results and may differ from estimates of state derived from a single-date analysis of the sample data. A constrained estimator of change in relative categorical frequencies that eliminates this potential inconsistency is proposed and a model based estimator of their sampling variance is developed. The performance of the constrained estimator is quantified against six criteria and a joint maximum likelihood estimator in simulated sampling from 15 populations with three combinations of permanent and temporary samples, four to six categorical class attributes, and constant size between sampling dates. Bias of the constrained estimators was negligible but larger than for joint maximum likelihood estimators. Mean absolute deviations and variances of constrained estimators were generally at par with the joint estimators. Constrained estimators of root mean square errors and achieved coverage of nominal confidence intervals of constrained estimators were occasionally better. A generalized variance function for the constrained estimates of change is provided as a computational shortcut.     

沙湾荒漠区生态环境的植物监测

利用植物生态学常规方法进行了荒漠植被种群生物量和数量特证调查,以植物为监测对象,并就群落地上部分生物量,Shannon-Wiener多样性指数,群落均匀度,生态优势度等指标探讨了在荒漠生态环境监测和评价中的具体应用。     

基于生态功能考虑的西北干旱地区生态需水研究

在当前生态需水研究的基础上,选取植被盖度作为衡量绿洲生态功能的主要指标,根据植被盖度和侵蚀率之间的关系,从生态系统的需水机理出发,提出了基于生态功能考虑的西北干旱地区生态需水量计算方法.以额济纳绿洲为例,计算了2000年额济纳绿洲生态需水,并与额济纳绿洲不同时期的生态需水进行了对比分析.     

焦化废水中有机污染物的特性及处理工艺方法的研究

研究了焦化废水中有机物的特性及有机污染物处理技术的发展动态和新方法。研究表明 ,生物法和物化新方法的联合工艺是处理焦化废水有机污染物的有效方法     

金陵石化炼油厂第二污水处理场改造工程介绍

金陵石化炼油厂第二污水处理场改造工程中对原有处理设施进行了工艺调整和优化，采用了均质，二级好氧生物处理及后浮选工艺，工程运行结果表明所采用的技术、设备是合理有效的。     

Degradation of Populus euphratica community in the lower reaches of the Tarim River, Xinjiang, China

IntroductionRiparian systems are aquatic-terrestrial ecotones withunique biotic , biophysical and landscape characteristics(Gregory, 1991 ; Naiman, 1997 ; Wiens , 2002) and areshaped by fluvial geomorphic processes . Riparian plantcommunities perform an i…     

冀南野生木本资源植物研究

冀南产野生木本资源植物200种，隶属43科91属。其中超过5种的科有13个，蔷薇科30种最多，其次为豆科24种，忍冬科、榆科、杨柳科均在10种以上。1、油松Pinustabulaeformis松科。木材可供建筑、电杆、矿柱、造船、家具及木纤维工业原料等用材；树干可提取松节油；树皮可提取栲胶     

湿式高效除尘脱硫装置的试验研究

本文介绍了一种高效除尘脱硫装置──三相流化床的性能和原理，并对三相流化床除尘脱硫工业中试系统的试验结果进行了分析．试验表明三相流化床除尘效率可达９８％，脱硫效率达７０％，运行安全可靠．     

用植物清除土壤中的重金属

介绍了生物修复技术去除土壤中的重金属及对植物的要求.植物能去除土壤中的有毒金属,将金属富集在生物体内,或将金属变成挥发性气体.