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Achieving exceptional wear resistance in a crack-free high-carbon tool steel fabricated by laser powder bed fusion without pre-heating

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journal of Materials Science & Technology 2023年第25期156卷 1-19页

作者： Konrad Kosiba Daniel Wolf Matthias bönisch Kai Neufeld Ruben Hühne Tobias Gustmann jozef bednarčík Hongyu Chen Xiaoliang Han Volker Hoffmann Lukas beyer Uta Kühn Sergio Scudino Lars Giebeler julia K.Hufenbach Leibniz Institute for Solid State and Materials Research (IFW) Dresden E.V. Helmholtzstr. 20Dresden 01069Germany Department of Materials Engineering KU LeuvenKasteelpark Arenberg 44bus 2450Leuven 3001Belgium Department of Condensed Matter Physics Institute of PhysicsP.J. Safarik University in KosicePark Angelinum 9Kosice 04154Slovakia Institute of Experimental Physics Slovak Academy of ScienceWatsonova 47Kosice 040 01Slovakia Key Laboratory of Impact and Safety Engineering of Ministry of Education of China Ningbo UniversityNingbo 315211China TU bergakademie Freiberg Institute of Materials ScienceGustav-Zeuner-Str. 5Freiberg 09599Germany

Laser powder bed fusion(LPbF)for the fabrication of dense components used for tooling applications,is highly *** stresses,which evolve in the additively manufactured part,are inherent to LPbF *** additional stress contribution in high-carbon steels arises from the austenite-to-martensite phase transformation,which may eventually lead to cracking or even *** an alternative to pre-heating the base plate,which is not striven by industry,lowering the martensite content which forms in the part,is essential for the fabrication of dense parts by LPbF of high-carbon tool steels which are then adapted to *** this study,a successful strategy demonstrates the processing of the Fe85Cr4Mo1V1W8C1(wt%)high-carbon steel by LPbF into dense parts(99.8%).The hierarchical microstructure consists of austenitic and martensitic grains separated by elemental segregations in which nanoscopic carbide particles form a network.A high density of microsegregation was observed at the molten pool boundary ultimately forming a *** LPbF-fabricated steel shows a yield strength,ultimate compressive stress,and total strain of 1210 MPa,3556 MPa,and 27.4%,*** mechanical and wear performance is rated against the industrially employed and highly wear-resistant 1.2379 tool steel taken as the *** its lower macro-hardness,the LPbF steel(58.6 HRC,0.0061 mm^(3) Nm^(-1))shows a higher wear resistance than the reference steel(62.6 HRC,0.0078 mm^(3) Nm^(-1)).This behavior results from the wear-induced formation of martensite in a microscale thick layer directly at the worn surface,as it was proven via high-energy X-ray diffraction mapping.

关键词： Additive manufacturing Laser powder bed fusion Steel Wear TRIP

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

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journal 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.Eckert 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

Presence of three dengue serotypes in Ouagadougou(burkina Faso):research and public health implications

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Infectious Diseases of Poverty 2016年第1期5卷 208-220页

作者： Valéry Ridde Isabelle Agier Emmanuel bonnet Mabel Carabali Kounbobr roch Dabiré Florence Fournet Antarou Ly Ivlabèhiré bertrand Meda beatriz Parra Department of Social and Preventive Medicine University of Montreal School of Public Health(ESPUM)MontréalCanada University of Montreal Public Health Research Institute(IRSPUM) Pavillon 7101 Avenue du ParcP.O.Box 6128Centre-ville StationMontrealQuebec H3C 3J7Canada Identités et Différenciations de l’Environnement des Espaces et des Sociétés–Caen(IDEES) University of Caen Basse-NormandieCaenFrance International Vaccine Institute Dengue Vaccine InitiativeSNU Research Park1 Gwanak-roGwanak-guSeoul 151-742Korea Institut de Recherche en Sciences de la Santé(IRSS) B.P.545 Bobo-DioulassoBurkina Faso UnitéMaladies infectieuses et vecteurs:écologie génétiqueévolution et contrôle(MIVEGEC)Institut de recherche pour le développement(IRD)B.P.171 Bobo-DioulassoBurkina Faso Institut de Recherche en Sciences de la Santé(IRSS) 03 B.P.7192 OuagadougouBurkina Faso Grupo de Virus Emergentes y Enfermedad Departamento de Microbiología Universidad del ValleCaliColombia

background:The significant malaria burden in Africa has often eclipsed other febrile *** Faso’s first dengue epidemic occurred in 1925 and the most recent in *** there is still very little known about dengue prevalence,its vector proliferation,and its poverty and equity ***:An exploratory cross-sectional survey was performed from December 2013 to january *** primary healthcare centers in Ouagadougou were selected based on previously reported presence of *** patients consulting with fever or having had fever within the previous week and with a negative rapid diagnostic test(RDT)for malaria were invited to *** data,healthcare use and expenses,mobility,health-related status,and vector control practices were captured using a *** samples of every eligible subject were obtained through finger pricks during the survey for dengue RDT using SD bIOLINE Dengue Duo(NS1Ag and IgG/IgM)®and to obtain blood spots for reverse transcription polymerase chain reaction(RT-PCR)*** a sample of randomly selected yards and those of patients,potential Aedes breeding sites were found and *** were collected and brought to the laboratory to monitor the emergence of adults and identify the ***:Of the 379 subjects,8.7%(33/379)had positive RDTs for *** the 2009 WHO classification,38.3%(145/379)had presumptive,probable,or confirmed dengue,based on either clinical symptoms or laboratory *** 60 samples tested by RT-PCR(33 from the positive tests and 27 from the subsample of negatives),15 were *** serotypes observed were DENV2,DENV3,and *** of dengue infection in 15-to-20-year-olds and persons over 50 years were 4.0(CI 95%:1.0–15.6)and 7.7(CI 95%:1.6–37.1)times higher,respectively,than in children under *** total spending for a dengue episode was 13771 FCFA[1300–67300 FCFA](1$US=478 FCFA).On average,2.6 breeding sites were found per yard.

关键词： Dengue Fever Acute febrile non-malaria cases burkina Faso Aedes Health system Cost Mobility

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接触斑点对蜗轮副承载能力的影响

机械传动 2014年第10期38卷 9-13,17页

作者： Hermes j. Hhn b.-R. Stahl K. Monz A. 陈金山 SEW-Eurodrive传动设备德国有限公司德国布鲁克塞尔76646 慕尼黑工业大学齿轮研究中心(FZG) 德国加兴85748 德国IMO集团公司德国格蕾姆斯多夫91350 浙江台玖精密机械有限公司浙江嘉兴314500

根据现有的技术发展水平,只有当蜗轮副的齿面完全啮合,才能评估其抗点蚀能力。但实际上,在蜗轮与蜗杆初始啮合时,它们只有一个较小的啮合斑点。由于时间和经费的关系,通过长时间轻载跑合使其达到完全啮合一般不太可能。在初期,由于接触... 详细信息

根据现有的技术发展水平,只有当蜗轮副的齿面完全啮合,才能评估其抗点蚀能力。但实际上,在蜗轮与蜗杆初始啮合时,它们只有一个较小的啮合斑点。由于时间和经费的关系,通过长时间轻载跑合使其达到完全啮合一般不太可能。在初期,由于接触面较小,齿部的接触应力会很大,有可能会在啮合处的表面产生一条微观裂纹,随后裂纹继续发展使材料从蜗轮上剥落,从而形成点蚀。较小的啮合斑点与点蚀的关系迄今还没有被系统的分析与研究,因此蜗轮轮齿也不能很好的进行优化。通过理论和实践相结合,提一种新的、可适用于不同尺寸、不同接触斑点位置以及齿形的计算方法,以弥补这一空白领域。

关键词：蜗轮蜗杆点蚀

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GLObAL ASYMPTOTIC STAbILITY IN N-SPECIES NONAUTONOMOUS LOTKA-VOLTERRACOMPETITIVE SYSTEMS WITH DELAYS

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Acta Mathematica Scientia 2003年第2期23卷 208-218页

作者：徐瑞陈兰荪 M.A.j.Chaplain Department of Mathematics Mechanical Engineering College Institute of Mathematics Academia Sinica Department of Mathematics University of Dundee

A delayed n-species nonautonomous Lotka-Volterra type competitive system without dominating instantaneous negative feedback is investigated. by means of a suitable Lyapunov functional, sufficient conditions are derived for the global asymptotic stability of the positive solutions of the system. As a corollary, it is shown that the global asymptotic stability of the positive solution is maintained provided that the delayed negative feedbacks dominate other interspecific interaction effects with delays and the delays are sufficiently small.

关键词： Nonautonomous Lotka-Volterra competitive system finite and infinite delay global asymptotic stability Lyapunov functional

Rhizosphere microbial communities associated to rose replant disease:links to plant growth and root metabolites

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Horticulture Research 2020年第1期7卷 1031-1046页

作者： b.Yim A.baumann G.Grunewaldt-Stöcker b.Liu L.beerhues S.Zühlke M.Sapp j.Nesme S.j.Sørensen K.Smalla T.Winkelmann Institute of Horticultural Production Systems Leibniz Universität Hannover30419 HannoverGermany julius Kühn-Institut(jKI) Institute for Epidemiology and Pathogen Diagnostics38104 BraunschweigGermany Institute of Pharmaceutical biology Technische Universität Braunschweig38106 BraunschweigGermany Faculty of Chemistry and Chemical biology(CCb) Technische Universität Dortmund44227 DortmundGermany Cluster of Excellence on Plant Sciences(CEPLAS) Institute for Population GeneticsHeinrich Heine University40225 DüsseldorfGermany Section of Microbiology Department of BiologyUniversity of Copenhagen2100 CopenhagenDenmark

Growth depression of Rosa plants at sites previously used to cultivate the same or closely related species is a typical symptom of rose replant disease(RRD).Currently,limited information is available on the causes and the etiology of RRD compared to apple replant disease(ARD).Thus,this study aimed at analyzing growth characteristics,root morphology,and root metabolites,as well as microbial communities in the rhizosphere of the susceptible rootstock Rosa corymbifera‘Laxa’grown in RRD-affected soil from two sites(Heidgraben and Sangerhausen),either untreated or disinfected byγ-*** a greenhouse bioassay,plants developed significantly more biomass in theγ-irradiated than in the untreated soils of both *** plant metabolites detected in ***‘Laxa’roots were site-and *** aloesin was recorded in significantly higher concentrations in untreated than inγ-irradiated soils from Heidgraben,the concentrations of phenylalanine were significantly lower in roots from untreated soil of both *** microbial communities of 8-week-old plants were studied by sequencing of 16S rRNA,ITS,and cox gene fragments amplified from total community *** by microscopic observations,sequences affiliated to the bacterial genus Streptomyces and the fungal genus Nectria were identified as potential causal agents of RRD in the soils *** relative abundance of oomycetes belonging to the genus Pythiogeton showed a negative correlation to the growth of the ***,the RRD symptoms,the effects of soil treatments on the composition of the rhizosphere microbial community revealed striking similarities to findings related to ARD.

关键词： soil roots plant

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一般人群中腹型肥胖和新发心房颤动的关系

中华高血压杂志 2017年第9期25卷 830-830页

作者：刘莉叶鹏 baek YS Yang PS Kim TH Uhm jS Park j Pak hn Lee MH joung b

已知身高越高,体质量越大,心房颤动发生风险越高。然而,心房颤动的风险是否与腹型肥胖有关尚不清楚。baek等纳入韩国国民健康保险计划全国样本队列中基线无心房颤动的成人501 690人,年龄（47.6±14.3）岁,女性250 664人,占50%。测定其... 详细信息

已知身高越高,体质量越大,心房颤动发生风险越高。然而,心房颤动的风险是否与腹型肥胖有关尚不清楚。baek等纳入韩国国民健康保险计划全国样本队列中基线无心房颤动的成人501 690人,年龄（47.6±14.3）岁,女性250 664人,占50%。测定其体质量指数（body mass index,bMI）和腰围,将bMI〈18．5kg／m2定义为低体质量，18．5～〈25．0kg／m2定义为正常体质量；25．0～〈30．0kg／m2定义为超重；≥30．0kg／m2定义为肥胖；将腰围≥90（男性）和≥80cm（女性）定义为腹型肥胖。

关键词：心房颤动腹型肥胖体质量保险计划国民健康基线队列腰围样本 body

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

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World journal of Hepatology 2015年第9期7卷 1287-1296页

作者： Kerstin Herzer Angela Papadopoulos-Khn Anne Achterfeld Ali Canbay Katja Piras-Straub Andreas Paul Andreas Walker jrg 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

基于MP2RAGE形态测量学评估神经性厌食症相关的脑萎缩

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国际医学放射学杂志 2018年第1期 120-120页

作者： j.boto G.Gkinis A.roch T.Kober b.Mareéchal N.Ortiz 柴超 Division of Neuroradiology Geneva University Hospital and Faculty of Medicine of Geneva

摘要目的采用具有自动脑分割功能的双磁化准备快速获得梯度回波(MP2RAGE)MRI序列评估神经性厌食症病人的脑萎缩。材料与方法于2014年8月—2016年12月

关键词：神经性厌食症 MP2RAGE 灰质体积脑萎缩