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排序方式: 共有670条查询结果,搜索用时 31 毫秒
31.
Using a membrane emulsification method based on porous hollow-fiber membranes in combination with an aqueous two-phase system (ATPS), we are able to produce “water-in-water” droplets with narrow-dispersed size distributions. The equilibrium phases of the aqueous two-phase system polyethylene glycol-dipotassium hydrogen phosphate are used for this purpose. The droplet diameter of a given fluid system is determined by the flow rates of the continuous and disperse phase as well as the hollow fiber dimensions. When diluting the disperse phase and thus moving the ATPS system out of equilibrium, the droplet size can be further reduced in comparison to the equilibrium case. Generally, droplets formed with this method have diameters 20%–60% larger than the inner hollow fiber diameter. The new strategy of diluting the disperse phase allows the production of droplet diameter below the inner diameter of the membrane. 相似文献
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The establishment of new academic specialties is an intriguing research topic from a social history of science perspective. In this article we focus on the ‘scientific migration’ within the Higher Institute of Physical Education (HIPE) and the Faculty of Medicine at the State University in Ghent, Belgium. The HIPE was ‘attached’ to the Faculty of Medicine in 1908, a world first that led to an interesting triangular relationship between physical education, physiotherapy, and medicine. The physiatrists (physicians-physiotherapists) who were appointed at the HIPE had to struggle with inferior status with respect to their colleagues within the Faculty of Medicine itself. Territorial power struggles arose on several levels. In 1936, after the first generation of physicians-physiotherapists had retired, physiotherapy was integrated fully into the Faculty of Medicine, and radiology and cancer treatment – which had been considered subsectors of physiotherapy – became autonomous specialties. Physical education, however, retained its inferior academic status. 相似文献
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This paper deals with the problem of constrained stability and tracking of Takagi–Sugeno (T–S) fuzzy positive systems. Linear programming (LP) is used to insert the constraints in the design phase while imposing positivity in closed-loop. The theoretical results are applied to the buck DC–DC converter which is widely used in the photovoltaic generators. Based on the simulation results success of the method is shown for this application. 相似文献
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Hans N. Weiler 《牛津教育评论》2013,39(1):15-27
Abstract Taking the political and scholarly debates about curriculum reform in the Federal Republic of Germany as a case in point, the article develops the notion of ‘compensatory legitimation’ as a theoretical construct for better understanding the political dynamics of making and implementing educational policy under conditions of conflict. Among various strategies of compensatory legitimation, special attention is given to the recourse to legal and constitutional norms, the utilisation of expertise, and the invocation of the discourse of participation. 相似文献
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Hans H. Wellisch 《Learned Publishing》1997,10(1):15-19
Differentiates items on a continuum of verbal texts as: books (single-author, small-team, multiple-author, encyclopedias); periodicals (journals, bulletins, bibliographic volume indexes, cumulations); databases. The requirements of their indexing, with varying problems of policy, language, depth, authors' names, and titles, in both printed and electronic form, are discussed. 相似文献
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