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Frontiers in Energy 2017年第2期11卷 119-125页

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

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

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

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

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

Heritability and Variability of Quality Parameters of Tomatoes in Outdoor Production

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Research 2020年第1期2020卷 1099-1107页

作者： christian.Zorb hans-Peter Piepho Sabine Zikeli Bernd Horneburg University of Hohenheim Institute of Crop Science70593 StuttgartGermany University of Kassel Section of Organic Plant Breeding and Agrobiodiversity27213 WitzenhausenGermany

The tomato is the most important vegetable *** England,outdoor tomatoes are widely grown by amateur gardeners,with the number of their allotment plots exceeding *** instance,in Germany,only about 16%of tomato plants are cultivated according to organic standards,although these rates are expected to *** for yield and fruit quality can increase resource ***,we need to evaluate the variability of yield and fruit quality parameters,to calculate the heritability of these traits and to identify superior genotypes for organic outdoor tomato production and *** these aims,we grew 24 tomato genotypes of diverse origins in a two-year field *** heritability of quality traits such as glucose,fructose,organic acid,and lycopene was *** medium heritability for yield suggests that trials with a larger number of locations are needed for the reliable selection of this *** correlations of sugar concentrations with fruit weight and of organic acid concentration with fruit weight and yield suggest trade-offs in breeding for larger fruits and higher *** for increased lycopene content is not subject to these challenges;the concentrations of the primary metabolite sugars and organic acids are positively correlated.

关键词： breeding sugar exceeding

Single and multiple stressor effect of road deicers and Cu on Atlantic salmon (Salmo salar) alevins from hatching till swim-up

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Journal of Environmental Sciences 2018年第4期30卷 368-378页

作者： Urma Mahrosh BjФrn Olav Rosseland Brit Salbu hans-christian.Teien Nortuegian Uniuersity of Life Sciences Department of Environmental Sciences N-1432 As Norway National University of Sciences and Technology H-12 Islamabad Pakistan Norwegian University of Life Sciences Department of Ecology and Natural Resource Management N-1432 As Norway

Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt（NaCl） and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations（100–1000 mg/L）,mortality was significantly higher compared to control. In exposure to Cu solutions（5–20 μg Cu/L）, no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions（road salt and Cu）, ultrafiltration of the exposure water demonstrated that only 20%–40% of Cu was present as positively charged low molecular mass（LMM） Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities,delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter–early spring period.

关键词： Road deicers Copper Atlantic salmon Alevins Biological effects

Between Scylla and Charybdis:The role of the human immune system in the pathogenesis of hepatitis C

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World Journal of Gastroenterology 2013年第44期19卷 7852-7866页

作者： Ulrich Spengler hans Dieter Nischalke Jacob Nattermann christian.P Strassburg Department of Internal Medicine 1 University of Bonn 53105 Bonn Germany

Hepatitis C virus(HCV)frequently elicits only mild immune responses so that it can often establish chronic *** this case HCV antigens persist and continue to stimulate the immune *** persistence then leads to profound changes in the infected host’s immune responsiveness,and eventually contributes to the pathology of chronic *** topic highlight summarizes changes associated with chronic hepatitis C concerning innate immunity(interferons,natural killer cells),adaptive immune responses(immunoglobulins,T cells,and mechanisms of immune regulation(regulatory T cells).Our overview clarifies that a strong anti-HCV immune response is frequently associated with acute severe tissue *** chronic hepatitis C,however,the effector arms of the immune system either become refractory to activation or take over regulatory *** together these changes in immunity may lead to persistent liver damage and ***,effector arms of the immune system will not only be considered with respect to antiviral defence but also as pivotal mechanisms of inflammation,necrosis and progression to ***,avoiding Scylla-a strong,sustained antiviral immune response with inital tissue damage-takes the infected host to virus-triggered immunopathology,which ultimately leads to cirrhosis and liver cancerthe realm of Charybdis.

关键词： Natural killer cells CD4+ T helper cells Regulatory T cells Interferon Hepatitis C Hepatic stellate cells Hepatocytes Immunoglobulin Retinoic acid inducible gene-I Toll like receptors

Phosphorus accumulation and leaching risk of greenhouse vegetable soils in Southeast China

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Pedosphere 2021年第5期31卷 683-693页

作者： Yusef KIANPOOR KALKHAJEH Biao HUANG Helle SORENSEN Peter EHOLM hans christian.BhansEN Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention School of Resources and EnvironmentAnhui Agricultural UniversityHefei 230036(China) Department of Plant and Environmental Sciences University of CopenhagenThorvaldsensvej 40Frederiksberg DK-1871 C(Denmark) Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008(China) Sino-Danish Center for Education and Research(SDC) Beijing 101408(China) Data Science Lab Department of Mathematical SciencesUniversity of CopenhagenUniversitetsparken 5DK-2100 Copenhagen East(Denmark)

Over-fertilization has caused significant phosphorus(P)accumulation in Chinese greenhouse vegetable production(GVP)*** study,for the first time,quantified profile P accumulation directly from soil P measurements,as well as subsoil P immobilization,in three alkaline coarse-textured GVP soil profiles with 5(S5),15(S15),and 30(S30)years of cultivation in Tongshan,Southeast *** each profile,soil samples were collected at depths of 0-10(topsoil),10-20,20-40,40-60,60-80,and 80-100 *** accumulation was estimated from the difference in P contents between topsoil and parent material(60-100 cm subsoil).Phosphorus mobility was assessed from measurements of water-soluble P concentration(P_(Sol)).Finally,P sorption isotherms were produced using a batch sorption experiment and fitted using a modified Langmuir *** total P contents of 1980(S5),3190(S15),and 2330(S30)mg kg^(-1) were measured in the topsoils versus lower total P content of approximately 600 mg kg^(-1) in the 80-100 cm ***,topsoil PSol values were very high,varying from 6.4 to 17.0 mg L^(-1).The estimated annual P accumulations in the topsoils were 397(S5),212(S15),and 78(S30)kg ha^(-1) year^(-1).Sorption isotherms demonstrated the dominance of P desorption in highly P-saturated topsoils,whereas the amount of adsorbed P increased in the 80-100 cm subsoils with slightly larger P adsorption *** total P adsorption capacity of the 80-100 cm subsoils at a solution P concentration of0.5 mg L^(-1) was 15.7(S5),8.7(S15),and 6.5(S30)kg ha^(-1),demonstrating that subsoils were unable to secure P concentrations in leaching water below 0.5 mg L^(-1) because of their insufficient P-binding capacity.

关键词： greenhouse vegetable production Langmuir model P adsorption capacity P desorption P immobilization P mobility subsoil topsoil