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1.
作为一类重要的持久性有机农药污染物所造成的危害已引起普遍关注,它们不仅会积留于动植物体内、直接影响我们的健康,而且还会威胁动物的生命健康。有机氯农药(简称Ocp)是一类组成里含有氯的有机杀虫剂、杀菌剂。一般分为两大类:一类是滴滴涕类,称为氯代苯及其衍生物,包括滴滴涕及六六六等;另一类是氯化甲撑萘类,如艾氏剂、狄氏剂、七氯、氯丹及毒杀芬等。我国曾经使用较多的是滴滴涕和六六六。传统提取底质中有机氯的方法为索式提取,而本文采用低污染有机溶剂对谷物进行萃取,气相色谱-质谱法检测,对多种有机氯农药的分离度较好。  相似文献   

2.
《中国科技信息》2003,(11):33-33
水循环系统运行时,如工业用循环冷却水系统或是发电厂内的水力循环系统经常会发生水垢污染问题,藻类、真菌、微生物及细菌日积月累滋生成长,堵塞了过滤器及阀门使水循环设备停摆,为抑制水垢生长,大量的杀菌剂(Biocide)、氯剂杀菌及臭氧剂早被广泛的使用,无形中已对水环保造成强大的  相似文献   

3.
液氯是给水工程中常用的消毒剂。它能杀灭水中的细菌,同时也危及人、畜安全。为了保证加氯系统正常运行及人身安全,淄博市引黄供水管理局在净水厂、配水厂设置了漏氯中和装置及堵漏装置。介绍了漏氯跑氯事故原因及处理措施。  相似文献   

4.
郭秀梅 《科技风》2014,(18):107-108
介绍了再生烟气脱氯技术在天津石化大芳烃装置上取代碱洗脱氯工艺的工业试验及运行情况。工业试验结果表明,采用固体脱氯剂法取代现有的UOP碱洗工艺,消除碱渣和废水的排放,简化、优化了脱氯工艺,具有操作简单、检测准确、方便等特点,再生烟气排放气中HCl体积分数含量小于1μL/L,低于国家排放要求。  相似文献   

5.
化合物氯代苯酚是有机化工中一类重要物质,在木材防腐、防锈剂、染料、农业化学品生物杀伤剂、农药除草剂和普通杀虫剂等方面有广泛应用。考虑到氯代苯酚精制过程的复杂性,笔者在自己工作经验基础上,结合参考有关文献,对该过程仪表选型做一论述。  相似文献   

6.
针对连续重整再生气体脱氯问题,如果采用固体脱氯剂替代原碱洗和水洗系统,不仅简化了工艺流程,而且还方便了操作。固态脱氯技术的应用,可以减少再生系统腐蚀,延长运行周期,同时降低了再生气体水含量,提高了催化剂再生性能,具有较好的经济效益和环保效益。  相似文献   

7.
提出了钢筋混凝土防腐技术和预防措施,并对混凝土中的Cl-含量确定了量化指标,通过试验验证了7种混凝土外加剂均能减缓氯盐对钢筋的腐蚀速度,强调了应建立有关融雪、破冰剂的技术质量标准和试验规程。  相似文献   

8.
吴敏 《内江科技》2010,31(10):106-106,20
早先的电冰箱全部采用感温囊式温控器控制,它是利用感温剂(一般为氟利昂12或氯烷)的热涨冷缩原理控制电路通断,从而达到对电冰箱制冷温度的控制。这种温控器灵敏度不高,并且随着使用时间的增加,温控器的性能参数发生飘移,导致了电冰箱内制冷温度出现偏差。本文设计的电子温控器克服了感温囊式温控器的弊端,使电冰箱的自动控制更加精确.  相似文献   

9.
氟氯烃(CFCs)可用作致冷剂、气溶胶喷射剂、发泡剂和清洗用溶剂,不过也会破坏平流层中的臭氧,从而加剧温室效应,现在化学工业部门正在开发CFCs的各种代用品。  相似文献   

10.
甲基三氯硅烷是“直接法”合成二甲基二氯硅烷单体过程中的主要副产物,其规模化处理和综合利用是实现有机硅工业可持续发展的关键。本文介绍了国内外将甲基三氯硅烷通过歧化、转化反应法制备其它重要甲基氯硅烷单体的研究进展。其中歧化法主要有一甲与三甲、一甲与高、低沸物两种反应体系;转化反应则包括甲基(氢)氯化铝法、直接加氢法、氯代转化法等;评述了以上几种甲基三氯硅烷利用途径中不同方法的特点,并对甲基三氯硅烷歧化、转化综合利用的工业化前景进行了展望。  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

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   

16.
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   

17.
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.  相似文献   

18.
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.  相似文献   

19.
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   

20.
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence  相似文献   

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