入世后环境预报气象服务应对措施研究

本文分析研究了我国加入WTO后，对地球环境预报气象服务的影响、带来的机遇和挑战并结合我国国情，从观念、法律、技术、人材等十个方面提出行之有效的应对措施。     

Al（Ⅲ）溶液的水解─沉淀特性研究─—磷酸根的作用

采用连续碱滴定方法和Ｘ射线衍射及红外光谱分析，研究了在Ａｌ（Ⅲ）－磷酸根溶液体系中，Ａｌ（Ⅲ）的水解－沉淀特性，结果表明，当Ｐ／Ａ１＞０．０５时，磷酸根对Ａｌ（Ⅲ）的水解－成核－沉淀过程有显著的促进作用，描述了磷酸根作用的动力学机理．     

地下水污染修复技术:可渗透反应墙

可渗透反应墙技术(permeable reactive barrier)是一种将溶解的污染物从污染水体中去除的钝性处理技术,是近年来比较流行的地下水污染原位处理方法,许多欧美国家已开始进入广泛的应用。介绍了该处理方法的基本原理、系统的主要结构类型、反应材料的选取等,并着重介绍了Fe0-PRB技术及其相关的技术。     

地下水污染修复的零价铁PRB技术

零价铁可渗透反应墙(Fe0-PRB)技术,已被证明是一项修复由卤代烃、卤代芳烃和有机氯农药以及一些有毒金属(如铬、硒、铀、砷和锝等)引起的地下水污染的有效技术.本文总结了国内外利用零价铁PRB修复受污染地下水的研究成果和动态,并结合当前该技术面临的问题分析了研究方向和发展前景.     

蓄热式热氧化器处理挥发性有机化合物

本文介绍了一种目前在欧美国家应用较成熟，但是国内尚无应用的VOC气体处理器-蓄热式热氧化器。     

Enumeration of Legionella pneumophila in cooling tower water systems

Legionella pneumophila, the causative agent of Legionnaires0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> disease, is known to colonise and frequently grow in cooling tower waters. Disease is acquired by inhaling aerosol contaminated by legionellae. Determination of the count of Legionella pneumophila in cooling tower waters may, therefore, be useful for risk assessment. In our survey, 103 water samples from 50 cooling towers were examined over a five-year period to indicate the seasonal distribution and the ecology of L. pneumophila, as regards temperature and pH. L. pneumophila serogroup 1 was found in 44% of the isolated strains, which is primarily responsible for the majority of Legionnaires0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> disease. The large majority of examined towers had levels of L. pneumophila in the high-risk category. These cooling towers have been linked to many outbreaks of Legionnaires0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> disease.     

Informing global environmental policy‐making: A plea for new methods of assessment and synthesis

Practice and research in assessment of global environmental change are dominated by two conventional assessment methods, formal models and expert panels. Models construct a representation of biophysical and socio0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">economic components of a policy issue, to project future trends or consequences of interventions. Panels articulate consensus views of policy0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">relevant knowledge through deliberations among selected experts. These methods make valuable contributions, but are weak in addressing certain kinds of knowledge needs that are typical of global0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">change issues. To address these needs, a set of novel assessment methods is proposed that combine elements of representation and deliberation. These methods, of which policy exercises, simulation0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">gaming, and scenario exercises are examples, involve human participants in structured relevant decision and task settings. Relative to models and panels, these methods can more readily incorporate diverse perspectives, can integrate across broader collections of knowledge domains, and can both encourage creative insights and innovations, and provide tests of their relevance and practicality. Risks of bias, and of over0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">confident generalization from unique experiences, are effectively mitigated by critical debriefings, and appear no more severe than corresponding risks in conventional assessment methods, or in policy0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">makers0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> generalizations from historical experience. While serious development and implementation challenges remain, early experience suggests that these methods can offer useful ideas and insights for policy0/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">making that are not available through other means.     

Biodegradation of starch-poly(β-hydroxybutyrate-co-valerate) composites in municipal activated sludge

Injection-molded composites were prepared by blending PHBV⁵ with native cornstarch (30% and 50%) and with cornstarch precoated with PEO as a binding agent. These composites were evaluated for their biodegradability in municipal activated sludge by measuring changes in their physical and chemical properties over a period of 35 days. All composites lost weight, ranging from 45 to 78% within 35 days. Interestingly, the extent and rate of weight loss were quite similar in PHBV composites with no starch, with 30% starch, and with 50% starch. Weight loss was slowest in PHBV blends prepared with PEO-coated starch. For all samples, the weight loss was accompanied by a rapid deterioration in tensile strength and percentage elongation. The deterioration of these mechanical properties exhibited a relative rate of PHBV>starch-PHBV>PEO-coated starch-PHBV. Changes in starch/PHBV composition after biodegradation were quantified by FTIR spectroscopy. Increasing the starch content resulted in more extensive starch degradation, while the PHBV content in the blends became less susceptible to hydrolytic enzymes.The mention of firms names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over firms or similar products not mentioned. All programs and services of the U.S. Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, marital status, or handicap.     

Accumulation of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid-co-4-hydroxyvaleric acid) by mutants and recombinant strains ofAlcaligenes eutrophus

Alcaligenes eutrophus accumulated a terpolyester of 3-hydroxybutyric acid (3HB), 3-hydroxyvaleric acid (3HV), and 4-hydroxyvaleric acid (4HV) during cultivation with 4HV as carbon and energy source under nitrogen starvation. The polyester accumulated by wild-type strains under these conditions contained 4HV at a molar fraction of approximately 5 mol% only. A catabolic pathway of 4HV was postulated, which included the activation of 4HV to 4HV-CoA and a conversion of 4HV-CoA to 3HV-CoA. Tn5::mob-induced mutants were isolated fromA. eutrophus HF39, which were affected in 4HV and/or valeric acid catabolism. Among 83 mutants were 27 4HV-negative or 4HV-leaky mutants; two mutants were identified which accumulated a terpolyester with a molar fraction of 10.1 to 22.7 mol% 4HV. In addition, a further increase in the molar fraction of 4HV in poly(3HB-co-3HV-co-4HV) and a two- to fourfold increase in the PHA synthase activity were monitored in these mutants or others and also in HF39, if the cells were complemented with the hybrid plasmid pHP1014::PP1, which contained the PHA biosynthesis genes ofA. eutrophus H16. Application of mutagenesis plus recombinant DNA techniques resulted in the accumulation of a terpolyester with up to 30 mol% 4HV and with approximately equimolar fractions of 3HB, 3HV, and 4HV.     

Calculation of carbon balances for evaluation of the biodegradability of polymers

Establishing carbon balances has been proven to be an applicable and powerful tool in testing biodegradability of polymers. In controlled degradation tests at a 4-L scale with the model polymer poly(0581m471k0q2772/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-hydroxybutyrate) (PHB), it was shown that the degree of degradation could not be determined with satisfactory accuracy from CO₂ release alone. Instead, the course of degradation was characterized by means of establishing carbon balances for the degradation of PHB withAcidovorax facilis and a mixed culture derived from compost. Different analytical methods for determining the different carbon fractions were adapted to the particular test conditions and compared. Quantitative determination of biomass and residual polymer were the main problems in establishing carbon balances. Amounts of biomass derived from protein measurements depend strongly on assumptions of the protein content of the biomass. Selective oxidation of biomass with hypochlorite was used as alternative, but here problems arose from insoluble metabolic products. Determination of soluble components with the method of chemical oxygen demand (COD) also includes empirical assumptions but seems acceptable if the dissolved carbon fraction is in the range of some 10% total carbon. Results confirm both analytical assays and theoretical approaches, in ending up at values very close to 100%, within an acceptable standard deviation range under test conditions comparable to standard test practice.Paper presented at the Bio/Environmentally Degradable Polymer Society014;Third National Meeting, June 6013;8, 1994, Boston, Massachusetts.