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1.
啤酒糖化中酶活力影响因素的分析   总被引:1,自引:0,他引:1  
麦芽汁的制备是啤酒生产的开始,其制备技术决定着麦芽汁的质量和麦芽汁的收得率,进而影响啤酒的质量和啤酒的产量。就糖化过程中对酶活力具有重要影响的因素(粉碎度、温度、PH值、糖化醪浓度)进行阐述,并给出了生产过程中具体的数值及范围,旨在为提高浸出率、缩短糖化时间、提高麦芽汁质量等方面提供理论支持。  相似文献   

2.
恒流变合成基钻井液是一种新型的钻井液体系,其流变性,特别是屈服值和低剪切速率下的粘度等参数不受温度压力的影响。利用线性回归方法对恒流变合成基钻井液流变模式进行优选,流变曲线拟合结果表明卡森、赫巴和宾汉三种流变模式均能较好的表征恒流变合成基钻井液的流变性。选用宾汉模式表征恒流变合成基钻井液流变性,并进行相关水力学计算,研究结果表明YP对ECD的影响大于PV对ECD的影响。  相似文献   

3.
孙佳 《内江科技》2013,(2):162-162
稠油的主要特征是粘度高、流动差等特性,但对温度敏感主要表现在从牛顿流体转变为非牛顿流体的温度差异上。转变温度越低,原油的流变特性越好,对注蒸汽热采越有利,反之则越不利。因此,目前开采稠油的主要方式是蒸汽热采,本文总结了热采机理及对蒸汽的要求,为其高效利用提供依据。  相似文献   

4.
正面银浆的印刷性与其流变性能有着紧密的联系。通常的研究中,关注最多的是浆料的粘度、屈服等流变数据。本文研究了正面银浆流变性能中壁面滑移在丝网印刷中的应用。通过不同壁面滑移测试方法的比较,建立了适宜的测试方法,发现不同测试方法对于准确表达壁面滑移特性是有区别的。壁面滑移越大的浆料过网性能越好,过低的壁面滑移会引起浆料断栅的可能性。  相似文献   

5.
采用废橡胶废塑料等裂解物为主要原料的温拌改性剂制备了低能耗改性沥青,通过沥青三大指标测试、布氏旋转粘度仪及动态剪切流变仪(DSR)对旋转薄膜烘箱老化(RTFOT)前、后的改性沥青进行基本性能分析。分析结果得出,废橡胶废塑料裂解物的温拌改性沥青老化前后的流变特性均比基质沥青优异,结合粘度、延度、软化点和针入度的结果可得沥青施工温度降低至少50℃,不仅能够实现低温施工,同时还能够提高沥青的高低温性能和抗老化性能。  相似文献   

6.
采用化学交联的方法,研究了以DCP为交联剂,SR444为助交联剂的交联体系对聚丙烯熔体粘度的影响,使用转矩流变仪表征了改性后聚丙烯的粘度变化。研究发现,体系的熔体粘度与SR444和DCP的相对量有关,当二者的用量相当,熔体粘度较高。通过挤出机发泡发现,体系熔体粘度高发泡效果好,熔体平衡扭矩为3.9Nm的PP,发泡的密度为0.398g/cm3。  相似文献   

7.
通过高温流变实验,揭示了合金凝固温区不同阶段的流变特性;提出准液相及准固相为五元件流变模型,而其过渡温区为六元件流变模型,并获得了相应的微分型本构方程。  相似文献   

8.
间歇聚合反应生产尼龙66粘度波动的讨论   总被引:1,自引:0,他引:1  
用乌氏粘度计对问歇生产尼龙664切片的粘度进行讨论。结果表明,粘度受温度、压力、醋酸等影响较大。除此之外,完成阶段和切粒阶段时间对粘度也有影响。尼龙66的粘度高低.体现了其分子量大小与分布情况,对下游产品性能至关重要。  相似文献   

9.
主要分析粉煤灰颗粒形态以及粉煤灰在水泥浆体组合体系中对浆体的流变特性的影响因素,并对其影响关系进行比较。  相似文献   

10.
采用自制的氯甲基倍半硅氧烷(CM-POSS)对环氧树脂E-51进行改性,考察了CM-POSS的加入量及温度对E-51/Me THPA/TEA体系粘度变化的影响规律,结果表明环氧体系粘度在室温条件下随CM-POSS加入量的增加而增加;当CM-POSS/E-51/Me THPA/TEA体系温度小于90℃时,体系粘度随着温度升高而下降,温度大于90℃时,粘度随着温度升高而迅速上升;当体系温度在35~50℃时,建立并求解了CM-POSS/E-51/Me THPA/TEA体系的流变模型,结果证明CM-POSS/E-51/Me THPA/TEA体系粘度变化规律符合Roller半经验模型。  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.
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.
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   

16.
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   

17.
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.
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.  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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