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Development of a 3D model for particle-wall collision and induced rotation and its influence on particle traj..tories

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Particuology 2024年第11期94卷 211-228页

作者： Cairen Miranda j.hn palmore j.. Department of Mechanical Engineering Virginia TechBlacksburg24060VAUSA Department of Mechanical Engineering University of WashingtonSeattle98195WAUSA

The present research focuses on improving the prediction of rotating particle *** particle-surface collision models do not accurately predict the particle rebound when taking rotation into *** data,such as the studies by Gorham and Kharaz(2000),Buck,Tang,Heinrich,Deen and Kuipers(2017),and Dong and Moys(2006)show that the Tsuj..Oshima and Morikawa(1985)model is inaccurate due to the incorrect tangential coefficient of restitution ***,Kuipers,Mohd Salleh,Stein,and Seville(2001)introduced a similar model to the work by Tsuj..et al.(1985)which includes a tangential coefficient of restitution but is only in two dimensions and does not consider out of plane *** work re-derives the particle collision model from the impulse equations for binary collisions in 3D while considering rotating *** derived equations in this work compares well to experimental particle-surface impact *** implications of this model are seen by investigating erosion due to particle collision in a simple pipe *** is shown that Tsuj..et al.(1985)over predicts the *** small differences in particle traj..tories between the present model and the Tsuj..et al.(1985)model will grow in complex flows with multiple close range particle impacts leading to inaccurate erosion predictions which will negatively impact the design of turbomachinery and pneumatic pipes.

关键词： Particle collisions CFD Rotation Three dimensional

Compositional complexity dependence of dislocation density and mechanical properties in high entropy alloy systems

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Progress in Natural Science:Materials International 2020年第4期30卷 545-551页

作者： P.Thirathipviwat G.Song j..ednarcik U.Kühn T.Gemming K.Nielsch j..an Leibniz Institute of Solid State and Materials Research (IFW Dresden) Frontier Research Center for Applied Atomic Sciences Ibaraki University Division of Advanced Materials Engineering and Institute for rare metals Kongju National University Institute of Physic Pavol Jozef Safarik University in Ko?ice Deutsches Elektronen-Synchrotron (DESY) Institute of Materials Science Technische Universit?t Dresden Institute of Applied Physics Technische Universit?t Dresden Korea Institute for Rare Metals Korea Institute of Industrial Technology (KITECH)

This study focuses on a quantitative analysis of dislocation accumulation after cold plastic deformation and mechanical properties of Fe Ni Co Cr Mn and Ti Nb Hf Ta Zr high entropy alloys(HEAs) which are single phase fcc and bcc solid solutions, respectively. In order to study the role of compositional complexity from unary to quinary compositions on dislocation accumulation and mechanical properties after plastic deformation, the single solid solution phase forming sub-alloys of the two HEAs were investigated. All studied samples revealed a large plastic deformability under cold-rotary swaging process by 85–90% area reduction without intermediate annealing. The dislocation density of all studied samples, determined by Williamson-Hall method on synchrotron X-ray diffraction patterns, were between 1014-1015m-2dependent on the alloy composition. The level of dislocation density after plastic deformation is not only affected by the number of constituent element but the lattice distortion and intrinsic properties in terms of stacking fault energy, modulus misfit, and melting point also impact the dislocation storage. The level of dislocation density determines the level of mechanical properties because of a resistance to dislocation motions. The hardness and yield compressive strength of the studied samples are proportional to the level of dislocation density.

关键词： High entropy alloys Dislocation density Synchrotron XRD Mechanical properties

Development of fatal acute liver failure in HIV-HBV coinfected patients

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World j..rnal of Gastroenterology 2010年第32期16卷 4107-4111页

作者： Albert M Anderson Marina B Mosunj.. Melody P palmore Melissa K Osborn Andrew j..uir Emory University School of Medicine Grady Health System Infectious Diseases Program341 Ponce de Leon AvenueAtlantaGA 30308United States Duke University School of Medicine DUMC 3913DurhamNorth CarolinaCA 27710United States

Coinfection with hepatitis B virus(HBV) is not uncommon in human immunodeficiency virus(HIV)-infected individuals and patients with HIV-HBV coinfection are at high risk for progression of liver *** guidelines regarding the treatment of HIV infection recommend that patients who are coinfected with HIV and HBV receive highly active antiretroviral therapy(HAART) with activity against hepatitis *** HIVHBV coinfected patients often experience liver enzyme elevations after starting antiretroviral therapy,acute liver failure(ALF) is rare and typically occurs with older antiretroviral agents with known potential for *** describe two cases of fatal ALF in the setting of HIV-HBV coinfection after initiation of *** cases occurred despite treatment with antiretrovirals that have activity against HBV and highlight the challenges in distinguishing drug hepatotoxicity and HBV immune reconstitution inflammatory ***-HBV coinfected patients should be monitored closely when initiating HAART,even when treatment includes agents that have activity against HBV.

关键词： Hepatitis B virus Human immunodeficiency virus Liver failure

Bio-inspired tetracarbene compounds as a new family of energy saving catalysts

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j..rnal of Energy Chemistry 2023年第4期79卷 559-561页

作者： Bo Zhang Fritz E.Kühn CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina' University of Chinese Academy of Science Beijing 100049China Molecular Catalysis Catalysis Research Center and Department of ChemistrySchool of Natural SciencesTechnical University of MunichLichtenbergstr 485748 Garching bei MünchenGermany

Efficient use of energy is a pressing *** of chemical processes is currently an important target for energy *** chemical processes are independent of pathways with respect to the final energy output or consumption,the application of catalysts can reduce involved activation energies considerably and therefore save large amounts of energy.

关键词： Catalysis Iron Carbenes Multidentate ligands

Microstructural Evolution and Mechanical Behaviour of Metastable Cu-Zr-Co Alloys

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j..rnal of Materials Science & Technology 2014年第6期30卷 584-589页

作者： S.Pauly K.Kosiba P.Gargarella B.Escher K.K.Song G.Wang U.Kühn j..ckert IFW Dresden Institut für Komplexe Materialien HelmholtzstraBe 20D-01069 Dresden Germany Laboratory for Microstructures Shanghai University TU Dresden Institut für WerkstoffwissenschaftD-01062 Dresden Germany

Three different Cu-Zr-Co alloys, namely Cu40Zr37.5Co22.5, Cu42.5Zr45Co12.5 and Cu49Zr49Co2, were obtained by rapid cooling. The microstructure and phase formation of as-cast rods with diameters of 2 mm are compared with those of the respective ingots. An increasing Co content stabilises the B2 CuZr phase and leads to the precipitation of a ternary Cu-Zr-Co phase. The variation of the cooling rate affects the size of the B2 dendrites as well as the volume fraction and the morphology of the interdendritic phases. The mechanical properties were determined in compression and all alloys show a certain plastic deformability despite the presence of several binary and ternary intermetallic phases. The deformation mechanisms are discussed on the basis of the microstructures and the constituent phases.

关键词： Bulk metallic glasses Microstructural evolution Mechanical behaviour

Hydromechanical behaviors of andesite under different stress states during fluid inj..tion

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j..rnal of Rock Mechanics and Geotechnical Engineering 2021年第4期13卷 727-744页

作者： Miao He Qi Li Xiaying Li Liang Xu Michael Kühn State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Fluid Systems Modelling Section GFZ German Research Centre for GeosciencesPotsdamGermany Institute of Earth and Environmental Science University of PotsdamPotsdamGermany

Water reinj..tion into the formation is an indispensable operation in many energy engineering *** operation involves a complex hydromechanical(HM)coupling process and sometimes even causes unpredictable disasters,such as induced *** is acknowledged that the relative magnitude and direction of the principal stresses significantly influence the HM behaviors of rocks during ***,due to the limitations of current testing techniques,it is still difficult to comprehensively conduct laboratory inj..tion tests under various stress conditions,such as in triaxial extension stress *** this end,a numerical study of HM changes in rocks during inj..tion under different stress states is *** this model,the saturated rock is first loaded to the target stress state under drainage conditions,and then the stress state is maintained and water is inj..ted from the top to simulate the formation inj..tion *** attention is given to the difference in HM changes under triaxial compression and extension *** includes the differences in the pore pressure propagation,mean effective stress,volumetric strain,and stress-induced *** numerical results demonstrate that the differential stress will significantly affect the HM behaviors of rocks,but the degree of influence is different under the two triaxial stress *** HM changes caused by the triaxial compression stress states are generally greater than those of extension,but the differences decrease with increasing differential stress,indicating that the increase in the differential stress will weaken the impact of the stress state on the HM *** addition,the shear failure potential of fracture planes with various inclination angles is analyzed and summarized under different stress *** is recommended that engineers could design suitable inj..tion schemes according to different tectonic stress fields versus fault occurrence to reduce the risk of

关键词： Water reinj..tion Stress state Hydromechanical(HM)coupling Inj..tion-induced seismicity Numerical modeling

No relationship between biopsy sites near the main testicular vessels or rete testis and successful sperm retrieval using conventional or microdissection biopsies in 220 non-obstructive azoospermic men

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Asian j..rnal of Andrology 2013年第6期15卷 795-798,I0009页

作者： j..llrich Schwarzer Heiko Steinfatt Heiko Steinfatt Manfred Schleyer Frank M Kōhn Klaus Fiedler2, Irene von Hertwig Gottfried Krüsmann Wolfgang Würfel Andrologie Centrum MOnchen MOnchen D-81241 Germany Kinderwunsch Centrum MOnchen MOnchen D-81241 Germany Andrologicum MOnchen MOnchen D-80331 Germany

In 220 consecutive patients with non-obstructive azoospermia, sperm retrieval was attempted by a combination of conventional and microdissection testicular sperm extraction （TESE）. For sperm retrieval, 2-3 conventional biopsies were performed followed by a microdissection TESE in cases of negative conventional biopsies. During the surgery, the vasculature of the testis was assessed using the operative microscope, and the location of positive biopsies was registered in relation to the blood supply. The overall sperm retrieval rate was 58.2%. From the initial conventional biopsies, sperm could be retrieved in 46.8% of the patients. With microdissection TESE, sperm could be retrieved from an additional 11.4% of the patients. The further use of microdissection TESE improved the sperm retrieval rate significantly （P=0.017）. No significant accumulation of positive biopsies was found towards the rete testis or the main testicular vessels.

关键词： intracytoplasmic sperm inj..tion male infertility microdissection testicular sperm extraction non-obstructiveazoospermia sperm retrieval

Laser additive manufactured high-performance Fe-based composites with unique strengthening structure

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j..rnal of Materials Science & Technology 2021年第30期89卷 242-252页

作者： Hongyu Chen Dongdong Gu Liang Deng Tiwen Lu Uta Kühn Konrad Kosiba College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China j..ngsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components Nanjing University of Aeronautics and AstronauticsNanjing 210016China Leibniz IFW Dresden Institute for Complex MaterialsP.O.Box 270116D-01069 DresdenGermany

Steel matrix composites(SMCs),reinforced by ceramic particles,have received a consistent attention in recent *** conventional methods to prepare SMCs is generally challenging,and the mechanical properties of conventionally fabricated SMCs are *** this study,we successfully fabricated highperformance SMCs by laser powder bed fusion(LPBF)of a composite powder consisting of Fe-based alloy powder and submicron-sized WC *** effect of laser energy density on the phase formation,microstructural evolution,overall density and resulting mechanical properties of LPBF-fabricated composites was *** present results show that a novel Fe_(2)W_(4)C carbidic network precipitates in the solidified microstructure entailing segregations along the boundaries of cellular *** presence of this carbidic network hampers the growth of sub-grains even at elevated temperatures,and hence,stabilizes the grain size though prepared at a broad range of different energy *** exact distribution of the Fe_(2)W_(4)C carbides depends on the employed laser energy densities,as for instance they are more uniformly distributed at higher energy *** density of LPBF samples reaches the maximum value of 99.4%at 150 j..m^(3).In this parameter set,high microhardness of~753 HV,compression strength of~3350 MPa and fracture strain of~24.4%are *** enhanced mechanical properties are ascribed to less metallurgical defects,higher volume fraction of the martensitic phase and increasing pile-up dislocations resulting from the pinning effect by Fe_(2)W_(4)C carbide.

关键词： Laser additive manufacturing Laser powder bed fusion Steel matrix composite Microstructures Mechanical properties

Management of telaprevir-based triple therapy for hepatitis C virus recurrence post liver transplant

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World j..rnal of Hepatology 2015年第9期7卷 1287-1296页

作者： Kerstin Herzer Angela Papadopoulos-Khn Anne Achterfeld Ali Canbay Katj..Piras-Straub Andreas Paul Andreas Walker j..g Timm Guido Gerken Department of Gastroenterology and Hepatology University Hospital Essen Department of General-Visceral and Transplantation Surgery University Hospital Essen Institute for Virology Heinrich Heine University

AIM: To characterize management of telaprevir(TVR)-based triple therapy of hepatitis C virus(HCV) reinfection after liver transplantation(LT).METHODS: We retrospectively analyzed safety and efficacy of telaprevir- based triple therapy in a single center cohort of 19 patients with HCV genotype(GT) 1 recurrence after LT, with respect to factors possibly predicting sustained viral response(SVR) or non-SVR. All patients were treated with TVR, pegylated(PEG) and ribavirine(RBV) for 12 wk followed by a dual phase with PEG/RBV for 12 wk in 7 patients and for 36 wk in 5 patients. RESULTS: In total 11/19(58%) of patients achieved a sustained response. All(11/11) SVR patients showed a rapid viral response at treatment weeks 4 and 11/14 rapid virological response(RVR) patients achieved SVR. Notably, all(7/7) patients who completed 48 wk of therapy and 80%(4/5) patients who completed 24 wk of therapy achieved SVR24. Treatment failure was significantly(P > 0.049) more frequent in GT1 a infection(5/7) compared to GT1b(3/12) infection and was associated with emergence of resistance-associated mutations in the NS3 protease domain. Bilirubin level at baseline is also related to SVR(P > 0.030). None of the patients had to discontinue treatment due to side effects. CONCLUSION: RVR, GT and bilirubin are clearly related to achievement of SVR. Providing a thorough patient selection and monitoring, a full course of TVR-based triple therapy in LT patients is feasible and achieves high SVR rates.

关键词： Liver transplantation Telaprevir HepatitisC virus recurrence Predictors Hepatitis C virus therapy