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针对传统的水质分析过程往往采用化学方法,容易造成二次污染。提出一种新的利用生物发光菌对河水化工污染等级进行测试的方法。通过分析发光菌的发光原理,利用有毒化学物质诱导细菌发光反应以及有毒物质抑制发光酶促反应的光减弱原理,对化学元素反映出不同的光强度特征进行采集,构建了发光细菌在化学污染环境下的可测量生长曲线。最后通过发光细菌毒性试验,建立发光细菌在一些重金属和有机污染物毒性作用下的发光强度的变化曲线,测定和判断水质受污染的等级。该方法的实验结果表现出较强的有效性和适应性,取得了较好的效果。 相似文献
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采用TCLP、国标、SPLP和SEP(F1+F2)4种不同重金属浸提方法对稳定化前后砷污染场地土壤进行毒性评估,实验结果表明,有效砷浸出率变化趋势为SEP(F1+F2)TCLP国标SPLP。当体系的p H在2.88~6.0范围内变化时,随p H增大,有效砷的浸出浓度减小;而当体系p H在7.0~9.0范围内变化时,有效砷的浸出浓度随体系p H增大而增大。生物有效性评估结果显示,两土样中砷的生物可给度明显降低,分别降低了22.2%和13.2%。ANC(酸中和容量)实验结果表明,稳定化处理前后两种土壤样品的酸中和能力变化不大。该试验可以为砷污染修复提供数据支持和方法参考。 相似文献
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废水中常见污染物为苯酚,其用途广泛但毒性和腐蚀性极强。为有效降低废水对环境污染程度,文中提出运用实验形式对废水中降解酵母菌进行筛选,采用毛细管气相色谱-质谱(GC-MS)联用仪分析可溶性有机物成分及含量。运用生物流化床驯化活性污泥,添加苯酚溶液并实行微生物驯化及富集,获取分离后的瓶形酵母菌;测试在不同降解时间、不同反应温度及不同酵母菌生物量等条件下,酵母菌降解废水能力,结果显示:酵母菌能够降解1500 mg/L浓度苯酚,反应最适宜温度为30℃,菌体为10.9~20.1μm×10.9~32.2μm降解性能最佳。利用毛细管气相色谱-质谱联用仪,采用吹脱捕集-GC-MS方法对可溶性有机物进行分析,分析结果表明废水中含有羧酸类,醇类,含氮、硫烃类和杂环化合物类等有机可溶性化合物。 相似文献
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酚类为原生质毒,属高毒物质。摄入高浓度酚时可引起人体急性中毒,长期摄入低浓度酚则可引起头昏、出疹、瘙痒、贫血及各种神经系统慢性中毒症状。在水质监测中挥发酚为必测项目,我国采用国际标准化组织颁布的4-氨基安替比林光度法为标准方法。该方法选择性高且稳定,环境监测分析人员经过长期实验比对,总结出实验中需要注意的事项及异常情况处理,以能够准确测定水中微量的挥发酚。 相似文献
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虾,蟹壳聚糖溶液粘度变化的研究 总被引：2，自引：0，他引：2
分别对虾、蟹壳聚糖溶液在不同浓度、p H值、温度下对其粘度变化的影响进行了研究 ,并对引起这些变化的原因进行了初步探讨 .结果表明 ,在溶液中蟹壳聚糖的降解速度比虾壳聚糖的降解速度快 ,在相同条件下虾壳聚糖溶液的粘度大于蟹壳聚糖溶液的粘度 .此结果对以壳聚糖为原料制备胶囊有着一定的理论意义和实际意义 相似文献
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聚合氯化铝是净水厂常用混凝剂,本文探讨了不同p H、温度和石灰与混凝剂投加顺序对混凝效果的影响,实验结果表明弱碱性的环境和较高的水温有利于提高聚合氯化铝的混凝效果,同时采用石灰对进水p H进行调节后再投加聚合氯化铝更有利于混凝过程。 相似文献
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针对空气中存在甲醛等有毒性挥发物质,以及化学药品挥发引起的二次空气污染,为此在室内环保设计中需要对空气甲醛的吸收能力与抗性进行研究。在室内封闭环境下,空气甲醛挥发较慢,需要通过绿色植物对其进行吸收及循环处理,采用当前方法时,主要以胺化剂制备常春藤纤维,采用傅里叶结合红外吸收光谱分析法,对常春藤的反应时间及反应的速度和浓度进行分析,存在甲醛吸收能力弱、抗性分析不准的问题。以虎尾兰叶片为例,在封闭环境下,对虎尾兰叶片进行不同浓度的甲醛胁迫实验,测定虎尾兰叶片在不同甲醛浓度环境下的对甲醛吸收能力。试验结果表明:虎尾兰具有很好的甲醛吸收能力,抗性较低,在净化空气方面具有更高实用价值。 相似文献
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饮用水的消毒是水处理过程中的重要工艺。本文绍了DBPs的基本信息,综述了消毒剂种类、投氯量、反应温度、p H、反应时间、溴离子、金属离子、氨氮等因素对DBPs生成的影响,为消毒条件的选择和水质安全保障提供参考。 相似文献
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A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
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Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
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Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献