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作者： hans-Joachim KRAUTZ Alexander LISK Joachim POSSELT christian KATZER Department for Power Plant Technology Brandenburg University of Technology Cottbus-Senftenberg 03046 Cottbus Gemany

Due to the fluctuating character of the renewable energy sources the demand of conventional power plants for flexibility is increasing. In the recent years, in Germany there has been a fast rise of production capacity of renewable energies, especially from wind turbines, photovoltaic installations, and biomass plants. The installed nominal power of wind turbines is actually (December 2016) 42 GW and of photovoltaic installations 40?GW. The renewable electric energy production in Germany is about 190?TWh/a, which represents a share of 33% of the yearly demand. The increased need for flexibility affects both the power gradients as well as the minimum load of conventional power plants. Due to this flexibility behaviour, conventional power plants are faced with problems concerning the durability of power plant components, corrosion, more maintenance effort and consequently the overall life expectancy. Another consequence of the increasing share of renewable energies is the decreasing full load operating hours, especially of coal fired and gas power plants. Along with decreasing revenues from the energy exchange market, coal fired power plants are faced with new economically challenges.

关键词： flexible load operation minimal load power gradients power plant maintenance corrosion life expectancy

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Investigation of the Flow in the Impeller Side Clearances of a Centrifugal Pump with Volute Casing

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Journal of Thermal Science 2012年第3期21卷 197-208页

作者： Bjrn-christian Will Friedrich-Karl Benra hans-Josef Dohmen Institute of Energy and Environmental Engineering TurbomachineryUniversity Duisburg-Essen

The paper is concerned with the fluid flow in the impeller side clearances of a centrifugal pump with volute *** flow conditions in these small axial gaps are of significant importance for a number of effects such as disk friction,leakage losses or hydraulic axial thrust to name but a *** the investigated single stage pump,the flow pattern in the volute turns out to be asymmetric even at design flow *** gain a detailed insight into the flow structure,numerical simulations of the complete pump including the impeller side clearances are ***,the hydraulic head and the radial pressure distributions in the impeller side clearances are measured and compared with the numerical *** configurations of the impeller,either with or without balancing holes,are ***,three different operating points,i.e.:design point,part load or overload conditions are *** addition,analytical calculations are accomplished to determine the pressure distri-butions in the impeller side *** accurate boundary conditions are available,the 1D flow models used in this paper can provide reasonable results for the radial static pressure distribution in the impeller side ***,a counter rotating wake region develops in the rear impeller side clearances in absence of balancing holes which severely affects the inflow and outflow conditions of the cavity in circumferential direction.

关键词： Cavity Rotor-Stator Cavities Side Chambers Centrifugal Pump

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Colorectal carcinogenesis-update and perspectives

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World Journal of Gastroenterology 2014年第48期20卷 18151-18164页

作者： hans Raskov hans-christian Pommergaard Jakob Burcharth Jacob Rosenberg Speciall?gecentret ved Diakonissestiftelsen 2000 Frederiksberg Denmark Department of Surgery Herlev Hospital University of Copenhagen DK-2730 Herlev Denmark

Colorectal cancer(CRC)is a very common malignancy in the Western World and despite advances in surgery,chemotherapy and screening,it is still the second leading cause of cancer deaths in this part of the *** factors are found important in the development of CRC including colonocyte metbolism,high risk luminal environment,inflammation,as well as lifestyle factors such as diet,tobacco,and alchohol *** recent years focus has turned towards the genetics and molecular biology of CRC and several interesting and promising correlations and pathways have been *** major genetic pathways of CRC are the Chromosome Instability Pathway representing the pathway of sporadic CRC through the K-ras,APC,and P53 mutations,and the Microsatellite Instability Pathway representing the pathway of he re di t ar y non-polyposis c olon c anc e r t hrough mutations in mismatch repair *** identify early cancers,screening programs have been initiated,and the leading strategy has been the use of faecal occult blood testing followed by colonoscopy in positive *** the treatment of colorectal cancer,significant advances have been made in the recent *** molecular targets of CRC include at least two important cell surface receptors:the epidermal growth factorreceptor and the vascular endothelial growth factor *** genetic and molecular knowledge of CRC has widen the scientific and clinical perspectives of diagnosing and ***,despite significant advances in the understanding and treatment of CRC,results from targeted therapy are still not *** studies will determine the role for this new treatment modality.

关键词： Colorectal carcinogenesis Risk factors Microbiology Genetics Diet Microbiome Inflammation

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Numerical Analysis of a System of Singularly Perturbed Convection-Diffusion Equations Related to Optimal Control

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Numerical Mathematics(Theory,Methods and Applications) 2011年第4期4卷 562-575页

作者： hans-Görg Roos christian Reibiger Technische Universität Dresden Institut für Numerische Mathematik01062 DresdenGermany

We consider an optimal control problem with an 1D singularly perturbed differential state *** solving such problems one uses the enhanced system of the state equation and its adjoint ***,we obtain a system of two convectiondiffusion *** linear finite elements on adapted grids we treat the effects of two layers arising at different boundaries of the *** proof uniform error estimates for this method on meshes of Shishkin *** present numerical results supporting our analysis.

关键词： Convection-diffusion linear finite elements a priori analysis layer-adapted meshes singular perturbed optimal control

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Rationality of quotients by linear actions of affine groups

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Science China Mathematics 2011年第8期54卷 1521-1532页

作者： BOGOMOLOV Fedor BHNING christian GRAF VON BOTHMER hans-christian Department of Mathematics Courant Institute of Mathematical Sciences New York University Mathematisches Institut University of Gottingen

LetG = SLn(C)Cn be the (special) affine group. In this paper we study the representation theory of G and in particular the question of rationality for V/G, where V is a generically free G-representation. We show that the answer to this question is positive (Theorem 6.1) if the dimension of V is sufficiently large and V is indecomposable. We explicitly characterize two-step extensions 0 → S → V → Q → 0, with completely reducible S and Q, whose rationality cannot be obtained by the methods presented here (Theorem 5.3).

关键词： rationality linear group quotients affine groups

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The emperor''s new clothes

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丛书名：津津有味·读经典

2012年

作者： (丹麦) hans Chridstian andersen原

本书收录了安徒生的四个故事, 分别是《老头子总是对的》、《海的女儿》、《拇指姑娘》和《皇帝的新装》。

ISBN: (纸本)9787544728263;9787895006157

本书收录了安徒生的四个故事, 分别是《老头子总是对的》、《海的女儿》、《拇指姑娘》和《皇帝的新装》。

关键词：童话

来源：畅想之星图书光盘版（南... 评论

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雪花莲

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疯狂英语（初中天地） 2006年第2期 24-28页

作者： hans christian.andersen 叶林

你见过雪花莲吗?如果没有,那就读一读安徒生的这个故事吧。看这个故事之前,小编可真是从没见过这种美丽的花。乍一看,以为这只是一个讲述雪花莲曲折经历的故事,但在最后,我们就会发现作者是借雪花莲赞扬丹麦的一位诗人。我们可能没听说... 详细信息

你见过雪花莲吗?如果没有,那就读一读安徒生的这个故事吧。看这个故事之前,小编可真是从没见过这种美丽的花。乍一看,以为这只是一个讲述雪花莲曲折经历的故事,但在最后,我们就会发现作者是借雪花莲赞扬丹麦的一位诗人。我们可能没听说过这位诗人,但故事歌颂的那些思想进步的人则存在于我们周围。隆冬之际,你可有留意身边开放的雪花莲?

关键词：雪花莲一朵花

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