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提高碱性蛋白酶生产效率的工艺条件研究 总被引：1，自引：0，他引：1
在地衣芽孢杆菌生长到对数期后期，添加０．０１％表面活性剂ＴＸ－１０碱性蛋白酶产量可提高２７．８％，当发酵液ｐＨ接近７．２左右时酶活接近峰值。此时应及时停止供氧，终止发酵；若继续通风培养４ｈ时可使酶活平均下降３８％左右。 相似文献
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高效液相色谱法测定饲料中色氨酸含量 总被引：3，自引：0，他引：3
样品用淀粉－氢氧化钡溶液１１０℃封管水解２４ｈ水解物用４ｍｏｌ／ＬＨＣｌ溶液调节ｐＨ至５～６以含１５％甲醇的０．０２ｍｏｌ／ＬＮａＡｃ缓冲溶液（ｐＨ＝４．５）为流动相,经高效液相色谱Ｃ１８柱分离,ＵＶ２８０ｎｍ检测,测定了饲料样品中色氨酸含量,方法简便,重现性好,回收率在９７．７％～１０４．１％之间。 相似文献
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报道了Ｉｏｄｏｇｅｎ法碘化标记单克隆抗体（单抗）的最佳条件和对标记单抗免疫活性影响的实验结果，结果表明，当Ｉｏｄｏｇｅｎ：ＭｃＡｂ＝１：４缓冲液ｐＨ＝７．４，旋涡搅拌１０ｍｉｎ时，标记率、放化纯和峰值百分率均较高，标记单抗的免疫活性与标记前比较没有统计学差异（Ｐ＞０．０５）。￣１３１Ｉ－ＨＣＭ８３和￣１２５Ｉ－ＶＣＭＣ与阳性对照结合率为３８．２％和３０．１％，Ｐ／Ｎ为９．１和３０．１。此通用技术具有推广应用价值。 相似文献
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碱性纤维素酶产生菌的筛选及其产酶条件 总被引：4，自引：0，他引：4
从土壤样品中筛选到一株产碱性纤维素酶的菌株ＳＹＨ－１,产酶的最适碳源为麸皮,最适氮源为豆饼粉,摇瓶发酵最高酶活２５ｕ／ｍＬ,酶反应的最适温度为５０℃,ｐＨ为９．６,主要作用底物为ＣＭＣ,对滤纸,纤维素粉和结晶纤维素几乎作用。 相似文献
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利用均匀设计法对Bacillus sp．ZJU318产酶的最佳培养基进行了快速优化研究。结果表明,其最适产酶培养基为：3．28％黄豆粉,0．023％蔗糖,0．075％K2HPO4,配制时的pH为12（灭菌后pH为8～9）;此外,其发酵的最佳条件为：发酵温度28℃,接种量20％,摇瓶装量20mL（250mL三角瓶）。在最适的发酵条件下,脂肪酶的发酵水平可达24．7U／mL。Bacillus sp．ZJU318脂肪酶作用的最适温度为45℃,40℃保温1h,活力几乎没有损失;但是,在50℃和60℃的条件下保温1h后,酶活降低得比较明显;酶作用的最适pH为9．0。在pH7～10,该脂肪酶较稳定,但是在酸性的环境中,酶的稳定性较低。 相似文献
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由控制饲料的ｐＨ值和缓冲液浓度来确定饲料的缓冲力，并配制不同水平的人工饲料饲育家蚕，检测三者间对饲料质量影响的主次。结果表明：饲料的缓冲力、ｐＨ值以及缓冲液度对家蚕的生长发育有显著影响，饲料缓冲液浓度和缓冲力的增加，饲料ｐＨ值的降低，都会引起蚕体重增量、相对生长率和净生长效率的降低，龄期经过的延长、消化后用于能量代谢的食物量的增加。在检验的ｐＨ值范围内（４．０￣５．５），饲料ｐＨ值对家蚕生长发育和 相似文献
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由控制饲料的ｐＨ值和缓冲液浓度来确定饲料的缓冲力，并配制不同水平的人工饲料饲育家蚕，检测三者间对饲料质量影响的主次．结果表明：饲料的缓冲力、ｐＨ值以及缓冲液浓度对家蚕的生长发育有显著影响．饲料缓冲液浓度和缓冲力的增加，饲料ｐＨ值的降低，都会引起蚕体重增量、相对生长率和净生长效率的降低，龄期经过的延长、消化后用于能量代谢的食物量的增加．在检验的ｐＨ值范围内（４．０～５．５），饲料ｐＨ值对家蚕生长发育和适口性的影响要小于饲料缓冲力，而略大于缓冲液浓度． 相似文献
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运用三元能量作用于马铃薯，其比对照组产量提高１９．１８％，结果个数增加１８．３０％，单薯重量减少０．５４％，经统计分析，前两项达到显著水平第３项差异不显著，证明了三元能量可促使马铃薯增产。 相似文献
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对５６例消化性溃疡患者，平分两组分别用奥美拉唑及进口洛赛克治疗４周。结果：奥美后唑总有效率９６％，洛赛克１００％，两者差异无显著性；两组治疗前后快速尿素酶试验阳性率相比差异无显著性；治疗前与治疗后胃液ｐＨ值相比两组差异均有高度显著性。奥美拉唑费用低，有推广价值。 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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《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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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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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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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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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
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Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献
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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
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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