臭氧室内空气质量评价标准的研究制订

通过分析O3毒理学研究和流行病学研究结果，参考国际权威机构制订的O3健康基准和国外相关标准，在考虑O3室内污染特点和我国目前污染水平的基础上，提出我国室内空气质量标准推荐值。     

应用δ~(13)C值探讨土壤中有机碳的迁移规律

C3 植物与C4 植物具明显的δ13C值差异 ,利用这种特性 ,选取荔波茂兰喀斯特森林边缘处这个C3植物—C4 植物转换生长的地点 ,分别采集森林与农田各三个剖面的土壤样品 ,根据测定其土壤总有机碳、不同粒径及不同比重组分的δ13C值间的相互关系来推导土壤有机碳的若干迁移规律     

银柱吸附,离子色谱法测定海水中的NO3--N

利用银柱吸附海水中的Cl-离子,然后通过电导法离子色谱测定海水中的NO3-_N。研究结果表明,使用该方法测定海水中的NO3-_N,分析方法简单,测试结果准确,同一样品多次测定结果的相对标准偏差低于2.0%,检测结果不受干扰,检出限为0.008mgL,是监控海水中NO3-_N的有效方法。     

一个研究街道峡谷流场及浓度场特征的三维数值模式

目前，研究街道峡谷内流场及机动车排放污染物的扩散行为特征所采用的主要方法为：采用野外测试法和物理模拟法，而采用三维数值模拟方法研究此问题的工作很少。本文创建了一个研究微尺度街道峡谷内流场及机动车排放污染物扩散特征的三维数值模式，即首次采用伪不定常方法，利用K——E闭合方案，建立了一个模拟城市街道峡谷内流场及污染物扩散特征与街道峡谷风场、街道几何结构及两侧建筑物高度对称性之间的复杂关系的三维数值模式。经过与实际监测资料及风洞实验对比，结果表明此三维模式具有较好的模拟精度，能够很好模拟峡谷内的风场及街谷几何结构对街道峡谷内流场及浓度场特征的影响，有很强的实用性。     

Microbial cycling of iron and sulfur in acidic coal mining lake sediments

Lakes caused by coal mining processes are characterized by low pH, low nutrient status, and high concentrations of Fe(II) and sulfate due to the oxidation of pyrite in the surrounding mine tailings. Fe(III) produced during Fe(II) oxidation precipitates to the anoxic acidic sediment, where the microbial reduction of Fe(III) is the dominant electron-accepting process for the oxidation of organic matter, apparently mediated by acidophilic Acidiphilium species. Those bacteria can reduce a great variety of Fe(III)-(hydr)oxides and reduce Fe(III) and oxygen simultaneously which might be due to the small differences in the redox potentials under low pH conditions. Due to the absence of sulfide, Fe(II) formed in the upper 6 cm of the sediment diffuses to oxic zones in the water layer where itcan be reoxidized by Acidithiobacillus species. Thus, acidic conditions are stabilized by the cycling of iron which inhibits fermentative and sulfate-reducing activities. With increasing sediment depth, the amount of reactive iron decrease, the pH increases above 5, and fermentative and as yet unknown Fe(III)-reducing bacteria are also involved in the reduction of Fe(III). Sulfate is reduced apparently by the activity of spore-forming sulfate reducers including new species of Desulfosporosinus that have their pH optimum similar to in situconditions and are not capable of growth at pH 7. However, generation of alkalinity via sulfate reduction is reduced by the anaerobic reoxidation of sulfide back to sulfate. Thus, the microbial cycling of iron at the oxic-anoxic interface and the anaerobic cycling of sulfur maintains environmental conditions appropriate for acidophilic Fe(III)-reducing and acid-tolerant sulfate-reducing microbial communities.     

Enhanced production of poly(3-hydroxybutyrate) by filamentation-suppressed recombinantEscherichia coli in a defined medium

Fed-batch cultures of recombinantEscherichia coli strains were carried out for the production of poly(3-hydroxybutyric acid) (PHB) in a chemically defined medium. TheE. coli strains used were XL1-Blue, harboring pSYL105, a stable high-copy number plasmid containing theAlcaligenes eutrophus polyhydroxyalkanoate (PHA) genes, and XL1-Blue, harboring pSYL107, which is pSYL105 containing theE. coli ftsZ gene to suppress filamentation. With XL1-Blue(pSYL105) the final cell mass and PHB concentration obtained in 62 h were 102 and 22.5 g/L, respectively. Fed-batch culture of XL1-Blue(pSYL107) under identical conditions resulted in a final cell mass and PHB concentration of 127.5 and 48.2 g/L, respectively. The PHB contents obtained with XL1-Blue(pSYL105) and XL1-Blue(pSYL107) were 22.1 and 37.8%, respectively. Therefore, PHB was more efficiently produced in a defined medium by employing filamentation-suppressed recombinantE. coli.     

ClO2处理含铁,锰及细菌饮用水的应用研究

为了除去水中高含量的铁，锰及细菌，采用ＣｌＯ２氧化Ｆｅ＾２＋，Ｍｎ＾２＋和灭菌的方法。研究结果表明，处理后水平铁，锰都末检出，细菌指标符合国家饮用水标准。此法具有工艺简单，操作方便，反应速度快，去除率极高，不产生致癌物质ＴＨＭ、且能很好地除水中的异味及色度等优点。此法适用于各种生活给水系统。     

Synthesis of Short-chain-length/Medium-chain-length Polyhydroxyalkanoate (PHA) Copolymers in Peroxisome of the Transgenic Arabidopsis Thaliana Harboring the PHA Synthase Gene from Pseudomonas sp. 61-3

In this paper, the photosynthetic production of short-chain-length/medium-chain-length polyhydroxyalkanoate (PHA) copolymers is reported. The wild-type and highly active doubly mutated PHA synthase 1 (S325T/Q481K, abbreviated ST/QK) genes from Pseudomonas sp. 61-3 were introduced into Arabidopsis thaliana. Peroxisome targeting signal 1 (PTS1) was used to target PHA synthases into the peroxisome to synthesize PHA from the intermediates of the β-oxidation pathway. The transgenic Arabidopsis produced PHA copolymers consisting of 40–57 mol% 3-hydroxybutyrate, 21–49 mol% 3-hydroxyvalerate, 8–18 mol% 3-hydroxyhexanoate, and 2–8 mol% 3-hydroxyoctanoate. The maximum PHA contents were 220μ g/g cell dry weight (cdw) in leaves, and 36μ g/g cdw in stems, respectively. The expression of the ST/QK mutated PHA synthase in leaves gene did not lead to significant difference in PHA content and monomer composition of PHAs, compared to the wild-type PHA synthase gene, suggesting that the supply of monomers may be a rate-determining step of PHA biosynthesis in the peroxisome. However, in stems, there were significant differences dependent on whether the wild-type or ST/QK mutated PHA synthase was expressed. These results suggest that tissue-specific monomer availability is important in determining the final mol% composition of PHA copolymers produced by the peroxisome in plants.     

青藏铁路救援指挥系统的研究

通过对青藏铁路特点及运营模式的分析,提出构建青藏铁路事故救援指挥系统的重要性。结合青藏铁路信息化总体规划,在充分利用青藏铁路各信息系统及通讯网络基础上,利用地理信息系统(GIS)技术和无线通讯技术,建设具有指挥、控制、通信及情报(C3I)功能的青藏铁路事故救援指挥系统。提出了系统应达到的目标功能,结合青藏铁路生产作业实际情况,给出了系统实现的信息流程、体系结构,并开发了原型系统。系统将青藏铁路多源信息整合并结合GIS技术以直观的电子地图、图像等方式展示出来,实现了救援预案管理和智能化查询、匹配;并通过应急无线通讯设备实现事故现场视频、图像实时播放及指挥调度与事故现场间的语音双向通讯;同时可建立事故数据库,为统计报告和事故分析服务。     

UV/O3复合降解水中2,4-二氯酚的试验研究

以紫外光源为主要依托,变换反应器中的不同工艺条件,分别对紫外光、臭氧和紫外/臭氧三种不同于工艺条件对水中污染物2,4-二氯酚(2 ,4-DCP)的降解规律进行研究.结果表明,UV/O3复合对2,4-DCP的降解较UV、O3单独作用效果好;溶液的酸碱度影响UV/O3对2 ,4-DCP的降解;此外,溶液中含有细菌时,E. coli的杀灭效果仍表现为UV/O3＞O3＞UV.细菌的杀灭和2,4-DCP的降解均消耗羟基自由基,形成竞争反应,从而影响到2,4-DCP的降解效果.