共查询到20条相似文献，搜索用时 62 毫秒
1.
高效液相色谱法测定农药样品马拉硫磷,样品用甲醇溶液提取测定。本研究方法为使用XDB—C18（150mm×4．6mm）的色谱分离柱,70％甲醇：30％水（V／V）为流动相,流速为0．8m1／min,最佳波长为220nm的紫外检测器。研究结果表明,在10-100mg／L浓度范围内峰面积与进样量呈良好的线性关系,相关系数r=0．9989;检测限为10．5μg／L（S／N=3）;相对标准偏差RSDS（n=5）1．10％,回收率为95．5％以上。 相似文献
2.
目的：建立索拉非尼的HPLC法测定含量。方法：采用phenomenex C8色谱柱（250mm×4．6μm×，5μm），流动相：三乙胺磷酸缓冲液（取纯水990mL，加入三乙胺10mL，用磷酸调节PH至5．4）-乙腈（60：40），检测波长250nm，流速：1．0mL／min。结果：索拉非尼浓度在200．17-480．41μg／mL范围内，与峰面积呈良好的的线性关系（r=0．9998），最低检测限为0．1ng。结论：本法简便，专属，重现性好，可用于测定索拉非尼含量。 相似文献
3.
建立反相高效液相色谱法测定复方川贝精片中五味子醇甲的含量。方法：采用奥泰公司C18色谱柱（250mm×4．6mm,5μm）,甲醇-水（60：40）,检测波长为250nm,流速为1．0ml／min,柱温为30℃。五味子醇甲在6．8-68．0μg·mL＾-1范围内呈良好的线性关系（r=O．99997）。五味子醇甲平均回收率分别为96．95％。结论：本法简便、准确,可用于复方川贝精片中五味子醇甲的含量测定。 相似文献
4.
动物性肌肉组织中多种磺胺类药物残留量的研究 总被引：1，自引：0，他引：1
采用ACQUITYUPLC^TMBEHC18柱（100mm×2．1mmi．d．,1．7μm）,以乙腈-0．2％乙酸水溶液（体积比1：9）为流动相;梯度洗脱;样品经乙腈和乙酸乙酯重复提取、饱和正己烷脱脂等处理;利用超高压液相色谱-电喷雾串联四极杆质谱联用（UPLC—MS／MS）技术,建立了一种能快速分离和测定动物性肌肉组织中多种磺胺类药物残留的方法。结果表明：该方法检出限（LOD）为0．04～1．35μg／kg;在1～200μg／ml范围内线性关系良好,回收率为63％～110．27％,可以满足各国对动物性食品中各种磺胺类药物的检测要求。 相似文献
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6.
本实验研究阿司匹林口腔崩解片的制备方法并建立反相高效液相色谱法测定阿司匹林口腔崩解片中阿司匹林的含量。方法：采用安捷伦十八烷基硅烷键合硅胶色谱柱（218mm×4．6mm,5μm）,乙腈-四氢呋喃-冰醋酸-水（23：5：5：61）,检测波长为280hm,流速为1．0ml／min,柱温为35℃。阿司匹林在0．1～1．8μg范围内呈良好的线性关系（r=0．99996）。阿司匹林平均回收率为标示量的99．1％。结论：本制剂稳定、可靠,测定方法简便、准确。 相似文献
7.
目的：测定谷丙甘氧酸胶囊中谷氧酸、丙氨酸、甘氧酸含量。方法：采用SS EXSIL ODS（250%＊4．6mm，5μm）色谱柱，0．05mol／L的醋酸钠溶液（pH6．4）：乙腈：水（70：15：5）为流动相的高效液相色谱法。结果：谷氧酸、丙氨酸、甘氨酸分别在132—308μg，48-112μg，24—56μg范围内线形良好（r=0．9998，0．9997，0．9996）；平均回收率分别为99．8％，99．8％，99．7；RSD分别为0．54％，0．62％，0．72％。结论：该方法简便快速，适用于谷丙甘氨酸胶囊中3组分含量的测定。’ 相似文献
8.
建立反相高效液相色谱法测定九气拈痛丸中橙皮菩的含量。方法：采用奥泰公司C18色谱柱（283mm×4．6mm,5μm）,甲醇-水（35：65）,检测波长为283nm,流速为1．0ml／min,拄温为30℃。橙皮苷在16．4～82．01μg·mL—11范围内呈良好的线性关系（r=0．99995）。橙皮苷平均回收率分别为99．76％。结论：本法简便、准确,可用于九气拈痛丸中橙皮苷的含量测定。 相似文献
9.
目的探讨糌粑中过氧化苯甲酰含量测定的HPLC法。方法高效液相色谱法,色谱条件：色谱柱为C18（150mm×4．6mm,5μm）,流动相为0．005mmol／L（PH=4．O）乙酸铵：乙腈（80＋20）,流速1．0mL／min,检测波长230nm。结果糌粑中过氧化苯甲酰被盐酸羟胺还原成苯甲酸,在此色谱条件下,苯甲酸在7min内出峰,峰面积与含量在0．01—0．20mg范围内成线性,r=0．9994,平均回收率为95．5％,相对标准偏差5．7％。结论该方法快速简便,可以满足食品检验的需要。 相似文献
10.
建立反相高效液相色谱法测定兰索拉唑口崩片中兰索拉唑的含量。方法：采用奥泰公司C18色谱柱（284mm×4．6mm,5μm）,甲醇-水-三乙胺-磷酸（640：360：5：1．5,pH为7．3）为流动相,检测波长为284nm,流速为1．0ml／min,柱温为30℃兰索拉唑在6．8-68．0μg·mL^-1范围内呈良好的线性关系（r=0．99995）。兰索拉唑平均回收率分别为100．1％。结论：本法简便、准确,可用于兰索拉唑口崩片中兰索拉唑的含量测定。 相似文献
11.
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
12.
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
13.
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
14.
《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
15.
《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
16.
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
17.
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
18.
Milton Mueller 《The Information Society》2001,17(3):151-163
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
19.
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.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
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
20.
Leah A. Lievrouw 《The Information Society》1998,14(2):83-96
The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests. 相似文献