Experimental Investigation into the Production Behavior of Methane Hydrate in Porous Sediment with Hot Brine Stimulation

The gas production behavior from methane hydrate in porous sediment by injecting the brine with the salinity of 0−24 wt % and the temperature of −1 to 130 °C was investigated in a one-dimensional experimental apparatus. The results show that the gas production process consists of three periods: the free gas production, the hydrate dissociation, and the general gas reservoir production. The hydrate dissociation accompanies the temperature decrease with the injection of the brine (NaCl solution), and the dissociation duration is shortened with the increase of the salinity. With the injection of hot brine, instantaneous hydrate dissociation rate also increases with the increase of the salinity. However, while the NaCl concentration is beyond a certain value, the rate has no longer continued increasing. Thermal efficiency and energy ratio for the hydrate production can be enhanced by injecting hot brine, and the enhanced effectiveness is quite good with the injection of high salinity at lower temperature.

Identification of a novel DNA methyltransferase 2 from the brine shrimp, Artemia franciscana

DNA methyltransferase 2 (Dnmt2) is a dual-specificity DNA methyltransferase, which contains a weak DNA methyltransferase and novel tRNA methyltransferase activity. However, its biological function is still enigmatic. To elucidate the expression profiles of Dnmt2 in Artemia franciscana, we isolated the gene encoding a Dnmt2 from A. franciscana and named it as AfDnmt2. The cDNA of AfDnmt2 contained a 1140-bp open reading frame that encoded a putative Dnmt2 protein of 379 amino acids exhibiting 32%similar to 39% identities with other known Dnmt2 homologs. This is the first report of a DNA methyltransferase gene in Crustacean. By using semi-quantitative RT-PCR, A)Dnmt2 was found to be expressed through all developmental stages and its expression increased during resumption of diapause cysts development. Southern blot analysis indicated the presence of multiple copies of AfDnmt2 genes in A. franciscana. (C) 2007 Published by Elsevier Inc.

Heavy metals in plants and phytoremediation - A state-of-the-art report with special reference to literature published in Chinese journals

Goal, Scope and Background. In some cases, soil, water and food are heavily polluted by heavy metals in China. To use plants to remediate heavy metal pollution would be an effective technique in pollution control. The accumulation of heavy metals in plants and the role of plants in removing pollutants should be understood in order to implement phytoremediation, which makes use of plants to extract, transfer and stabilize heavy metals from soil and water. Methods. The information has been compiled from Chinese publications stemming mostly from the last decade, to show the research results on heavy metals in plants and the role of plants in controlling heavy metal pollution, and to provide a general outlook of phytoremediation in China. Related references from scientific journals and university journals are searched and summarized in sections concerning the accumulation of heavy metals in plants, plants for heavy metal purification and phytoremediation techniques. Results and Discussion. Plants can take up heavy metals by their roots, or even via their stems and leaves, and accumulate them in their organs. Plants take up elements selectively. Accumulation and distribution of heavy metals in the plant depends on the plant species, element species, chemical and bioavailiability, redox, pH, cation exchange capacity, dissolved oxygen, temperature and secretion of roots. Plants are employed in the decontamination of heavy metals from polluted water and have demonstrated high performances in treating mineral tailing water and industrial effluents. The purification capacity of heavy metals by plants are affected by several factors, such as the concentration of the heavy metals, species of elements, plant species, exposure duration, temperature and pH. Conclusions. Phytoremediation, which makes use of vegetation to remove, detoxify, or stabilize persistent pollutants, is a green and environmentally-friendly tool for cleaning polluted soil and water. The advantage of high biomass productive and easy disposal makes plants most useful to remediate heavy metals on site. Recommendations and Outlook. Based on knowledge of the heavy metal accumulation in plants, it is possible to select those species of crops and pasturage herbs, which accumulate fewer heavy metals, for food cultivation and fodder for animals; and to select those hyperaccumulation species for extracting heavy metals from soil and water. Studies on the mechanisms and application of hyperaccumulation are necessary in China for developing phytoremediation.

二氧化碳收集利用与处置技术分析

化石燃料的燃烧是百余年来大气中二氧化碳（CO2）浓度增加的主要原因。CO2的收集和处置则是抑制这一趋势的有效途径。本文通过对现有收集利用和处置技术的分析，认为火电厂是收集CO2的重点考虑对象；CO2用于三次采油及天然气回收在技术上和经济上比较可行；蓄水层储气前景广阔值得研究；深海处置有待进一步探索；CO2用于置换开采天然气水合物也是很有前景的方案。

中国医疗废物优化处置技术和管理模式研究

本论文在综合分析国内外医疗废物处置技术及其应用管理模式的基础上，结合中国医疗废物管理和处置现状，提出了中国医疗废物处置技术选择及应用模式，并对如何优化现行医疗废物处置技术和管理模式问题进行了系统的研究。主要研究成果包括： 1．中国医疗废物处置技术选择和应用模式研究。该项研究是在系统研究国际组织和国际公约、国内外医疗废物处置技术应用状况和管理模式基础上，结合中国医疗废物的产生、处置技术应用以及环境管理模式的特点和存在的问题，针对焚烧和非焚烧两大技术流派开展的。 2．中国医疗废物处置技术和管理模式优化研究。该研究是结合中国医疗废物处置技术应用和管理现状以及推进采用BAT/BEP的总体要求出发，结合具体案例提出了典型医疗废物处置技术优化所涉及工艺配置、工况参数以及污染控制要求，提出了以生命周期和全过程管理为核心的医疗废物管理理念，并就技术和管理模式优化的评价方法问题，提出了焚烧处置设施的性能评价方法以及非焚烧处理设施处理效果评价方法。 相关研究成果的意义在于可以为我国医疗废物领域相关技术选择、工程建设、设施运行、监督管理以及环境监测/检测方法的研究和应用提供借鉴，为推进医疗废物领域探索和采用BAT/BEP提供了技术支持。

危险弹药销毁用聚能引爆器设计

为解决炸药包殉爆销毁存在的诸多问题,适应新形势下部队训练保障要求,依据前人关于聚能装置设计经验和聚能效应原理,着重阐述了炸药、药型罩、炸高、外壳等重要参数设计原则及其选取依据,设计了一种用于危险弹药销毁的新型装置.为检验聚能引爆器侵彻引爆销毁危险弹药的能力,选取了5种典型弹药进行实弹销毁试验.试验结果表明:该装置能够引爆不同弹丸装药、不同弹体材料、不同弹丸壁厚的危险弹药,用于销毁危险弹药是可行的

投加溶胞菌群对剩余污泥消化影响的初步研究

活性污泥法是目前世界上普遍应用的污水生物处理工艺，其在运行过程中产生大量的剩余污泥。由于剩余污泥处理费用巨大及污泥最终处置对环境具有潜在危害问题，污泥的处理和处置已经成为水处理领域关注的焦点。本文利用实验室筛选的溶胞菌群，在好氧消化的同时对污泥进行前处理，促进剩余污泥的破解与溶胞，再通过两相厌氧处理对污泥进行进一步消化，以研究投加溶胞菌对剩余污泥消化的影响。 本研究中溶胞菌污泥减量化技术分为两个部分，第一，污泥在溶胞菌作用下的好氧消化与污泥传统好氧消化的对比研究，利用取自成都三瓦窑污水处理厂剩余污泥，向好氧污泥消化反应器中投加溶胞菌，检测各项污泥指标，并通过同传统好氧污泥消化对比，以研究溶胞菌对污泥好氧消化的影响。第二， 经过溶胞菌处理后好氧消化的剩余污泥进行两相厌氧处理研究。通过建立好氧溶胞联合两相厌氧消化系统的来处理剩余污泥，并与相同条件运行的两相厌氧消化系统做对比，检测运行过程中系统中物质成分变化，研究了其处理能力和运行稳定性，探索了两相厌氧消化系统中的发酵类型差别，验证了好氧溶胞对剩余污泥的破解效果。 研究结果表明：污泥在溶胞菌作用下的好氧消化效果和消化效率均优于传统好氧消化。在溶胞菌群存在的情况下，剩余污泥的TSS和VSS去除率达到40%和53%，远高于传统好氧消化的12%和20%。污泥经过溶胞及好氧消化后，TCOD去除率达到54.4%。经过溶胞菌处理后的剩余污泥再进入两相厌氧处理系统，进入厌氧处理系统的剩余污泥的VSS／TSS比值约为0.62。在两相厌氧处理水力停留时间(HRT)为8d时，溶胞处理污泥厌氧消化后VSS去除率达到55.17%，对照组两相厌氧系统的VSS去除率平均值为18.53%。经过溶胞处理的两相厌氧系统的污泥减量了能力远高于对照组。两相厌氧系统的pH值和碱度说明系统运行较为稳定。产酸相的有机酸中乙酸含量高于丙酸和丁酸，说明发酵末端产物以乙酸为主。在20天的试验周期内，污泥溶胞处理后、两相厌氧系统产甲烷相产气量累积产气量为1.2L，对照组只有375ml。气体中甲烷含量都在55%左右。该研究结果表明，好氧溶胞对污泥有破解能力，溶胞处理对两相厌氧中产酸相水解污泥细胞有明显的促进作用，提高了产酸相的水解酸化能力和效率。该研究对于利用生物溶胞途径提高污泥消化效率具有重要意义。 The actived sludge process has been used more and more extensively, but the procedure will lead to a large quantity of excess sludge. The treatment of Excess activated sludge has becomes a focuses not only for it is a seriously negative effect on environment but also for the costly disposal comes subsequently. The cell lysing bacterium was keeped in our lab to joined in the digestion of the excess activated sludge which was carrying at the same time with pre-processing of sludge to investigated the influence of cell lysing bacterium on excess sludge. There are two part in the method of cell lysing bacterium digesting sludge technology, the first, comparison of excess sludge digestion between anaerobic Cell-lysing Pretreatment and Conventional Aerobic Process. The sludge which was collected from San Wanyao disposal plant in Chengdu was thrown into the aerobic process system with cell-lysing bacterium, then, the indexes were detected to compare the difference between the cell-lysing bacterium in aerobic process and the traditional method to determine the influence of cell-lysing bacterium on aerobic process ; The second, the research on the sludge which was pro-treated with cell-lysing and aerobic digestion in the diphase of anaerobic digestion system. The system of cell-lysing combined with diphase of anaerobic digesting was created to compare to the diphase of anaerobic digested system, the changes of mass constituent was detected to study the ability and steady of disposal. Moreover, the research explored the difference among the types of fermentation. The efficacious of aerobic process was been proved. The result shows that the digesting rate of aerobic process with cell-lysing bacterium was higher than the traditional process. The ratio of sludge is reach to 40%~53%, which was far more effectively than the traditional process rate of 12%~20%. The TCOD of sludge which was treated with cell lysing bacterium and Aerobic Process is reach to 54.4%. Then, the sludge was thrown into the diphase of anaerobic digesting system. VSS／TSS of sludge is 0.62, HRT is 6d, the reduction of VSS is reach to 40.8%. The pH and alkalinity indicate the steady running of the diphase anaerobic digest system. In the acerbity phasing, the content of acetic acid was more than butanoic acid and propanoic acid in organic acid, it is demonstrated that the main composition of final production of fermentation was Acetic Acid. During the 20d of experiment, methylhydride phasing of diphase anaerobic digest system produced 1.2L methylhydride, however, there is only 375ml in CK, the content of methylhydride in all gas phase was around the rate of 55%. The average ratio of VSS was 18.53% in CK diphase anaerobic digest system which was far more unavailable than the mass sludge rate of 55.17%. Results demonstrated that aerobic cell-lysing digested the sludge, the treat of cell-lysing could obviously promoted the hydrolyzeing of sludge cell in the acerbity phasing, which improved the ability and rate of hydrolization and acidification. This study is significant in inhenceing the rate of sludge digestion in the method of cell-lysing bacterium.

弱小信号处理电路的研制

无论是在核物理和粒子物理实验中，我们常常需要对探测到的弱小信号进行线性处理，以满足测量与分析的要求。为此，我们以弱小信号处理为题，开展了一些研究工作，我们先后开展的研究工作包括以下几个方面：1．弱电流测试仪的研制2．电荷前放的研制3．主放的研制这三种仪器我们将在沦文的第二、第三、第四章分别进行阐述。弱电流测试仪是一种便携式仪器（直接由22OV供电），它可以测量0．1 nA至100tlA范围的弱小电流（测量范围分六档可调）。它可以接受正或负极性直流输入电流。输出采用两种方式：表头直读和电压输出。电压输出最大为＋5V。电荷前置放大器具有电路结构简单、体积小（38m×45mm×80mfll）、输出信号上升时间快、噪声低、稳定性好等特点。主放成形时间常数分为四档：0．5 us、1 us、2 us、3 us：放大倍数分为两档：×10、×100；峰保持时间为6us左右（确保后续ADC所需的时间）；具有价格低、性能好、体积小的特点。在论文的第五部分论述的是根据在调试过程中出现的实际问题提出的解决办法，其中最主要的是对各种噪燕的解决办法。上述仪器研制完成后，在实际使用中，获得了满意的结果，受到好评。

污泥的农林处置与利用

Three problems of disposal and utilization of sludge are necessary to be solved by applying it in agriculture and forestry:①The possoblity of heavy metals in sludge causing second pollution to soil and crops.②The potential effect of pathogens on the environment.③Groundwater pollution caused by high N and P concentration.The aiteratures on the above three problems home and abroad were summarized in this paper.

Comparison of two marine sponge-associated Penicillium strains DQ25 and SC10: differences in secondary metabolites and their bioactivities

Two strains of Penicillium, DQ25 and SC10, isolated from marine sponge Haliclona angulata (Bowerbank) and Hymeniacidon sp. respectively, were subjected to stationary cultivation under GYP medium for 30 days. The fermentation extracts were undergone bioactivities assays against human pathogens, phytopathogenic fungi and brine shrimp (Artemia salina). Bioassays-guided compounds isolation was performed by Silica gel columns and Sephadex LH-20 chromatography. Spectroscopic methods were used to structures elucidation of the compounds. Results showed the activities of secondary metabolites of strain DQ25 were generally stronger than that of strain SC10. Major bioactive molecules isolated from strain DQ25 were a 1,4-naphthoquinone derivative and an unidentified alkaloid. The two components were not isolated from the extract of strain SC10. ITS sequences revealed that these two species have the greatest similarity with Penicillium vinaceum and Penicillium granulatum respectively.

Diet-induced changes in lipid and fatty acid composition of Artemia salina

The influence of diet on lipid and fatty acid composition of the brine shrimp Artemia salina nauplii was investigated. Various diets with different lipid composition and fatty acid profiles were fed to nauplii for 2 weeks. The lipid composition of microalgal diets, Isochrysis galbana, Phaeodactylum tricornutum and Nannochloropsis oculata and baker's yeast was analyzed. Newly hatched nauplii were examined before the feeding experiment. It was shown that Artemia was able to incorporate and selectively concentrate some dietary lipids. Depot lipids were more sensitive to changes in the dietary lipid composition than the main structural lipids, polar lipids and sterols. Variations in the content of the lipid classes correlated with stage of development of the animal. The fatty acid composition of the animal varied with that of diet. The concentrations of saturated fatty acids were apparently supported in the nauplii by biosynthesis de novo. The acid 16:1(n-7) originated from the food. The concentration range of n-6 polyunsaturated fatty acids (PUFAs) remained constant through the accumulation from the diet. The proportion of n-3 PUFAs varied with their level in the diet. The dynamics of alteration of 20:5(n-3) content in Artemia fed on Isochrysis, which is poor in this acid, suggested a limited capacity for elongation and desaturation of 18:3(n-3) to 20:5(n-3). None of the diets provided dietary input of 22:6(n-3). (C) 1998 Elsevier Science Inc. All rights reserved.