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Microstructure and Fracture Behavior of 316L Austenitic Stainless Steel Produced by Selective Laser Melting

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journal of Materials Science & Technology 2016年第8期32卷 738-744页

作者： r.Casati j.Lemke M.Vedani Department of Mechanical Engineering Politecnico di Milano

Selective laser melting is an additive manufacturing method based on local melting of a metal powder bed by a high power laser beam. Fast laser scans are responsible for severe thermal gradients and high cooling rates which produce complex hydrodynamic fluid flow. These phenomena affect crystal growth and orientation and are believed to be the cause of material spattering and microstructural defects, e.g. pores and incompletely melted particles. In this work, the microstructure and texture of 316L bars built along two different orientations and the effect of different distribution of defects on their mechanical response and failure mechanisms were investigated. Partially molten powder particles are believed to be responsible for the scattering in elongation to failure, reduced strength, and premature failure of vertical samples.

关键词： AISI 316L Additive manufacturing Selective laser melting Microstructural analysis Fracture behavior

Effect of Base Material on Microstructure and Texture Evolution of a Ti–6Al–4V Electron-Beam Welded joint

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Acta Metallurgica Sinica(English Letters) 2017年第5期30卷 499-504页

作者： G.Q.Wang Z.B.Zhao B.B.Yu j.r.Liu Q.j.Wang j.H.Zhang r.Yang j.W.Li School of Materials Science and Engineering University of Science and Technology of China Institute of Metal research Chinese Academy of Sciences Science and Technology on Power Beam Processes Laboratory Beijing Aeronautical Manufacturing Technology Research Institute

The effect of base material（BM） on microstructure and crystallographic orientation evolution of a Ti–6Al–4V electron-beam welded joint was investigated. Meanwhile, the crystallographic orientation of prior b grains was studied by advanced electron backscattered diffraction data processing. The inhomogeneity of microstructure within welded joint was formed due to the different microstructures of BM. By comparing microstructure details of the welded joint, including microstructure morphology and crystallographic orientation with those of the base material, it can be found that both the microstructure morphology and crystallographic orientation of the EBW joint would be controlled by BM.

关键词： Electron-beam welding Titanium alloys Prior b orientation Microstructure Texture

A discrete contact model for complex arbitrary-shaped convex geometries

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Particuology 2023年第9期80卷 180-191页

作者： jan E.Marquardt Ulrich j.römer Hermann Nirschl Mathias j.Krause Lattice Boltzmann research Group Karlsruhe Institute of TechnologyStraße am Forum 8Karlsruhe76131Germany Institute for Mechanical Process Engineering and Mechanics Karlsruhe Institute of TechnologyStraße am Forum 8Karlsruhe76131Germany Institute of Engineering Mechanics Karlsruhe Institute of TechnologyKaiserstraße 10Karlsruhe76131Germany Institute for Applied and Numerical Mathematics Karlsruhe Institute of TechnologyEnglerstraße 2Karlsruhe76131Germany

The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on ***,the simultaneous consideration of complex particle shapes and four-way coupling remains a major *** is mainly due to a lack of suitable contact *** models for complex shapes have been proposed in literature,and most limit the accuracy of the particle-fluid *** this reason,this paper presents a novel contact model for complex convex particle shapes for use with partially saturated methods,in which we propose to obtain necessary contact properties,such as the indentation depth,by a discretization of the contact *** goal of the proposed model is to enable comprehensive and accurate studies of particulate flows,especially with high volume fractions,that lead to new insights and contribute to the improvement of existing industrial *** ensure correctness and sustainability,we validate the model extensively by studying cases with and without *** the latter case,we use the homogenized lattice Boltzmann *** provided investigations show a great agreement of the proposed discrete contact model with analytical solutions and the literature.

关键词： Partially saturated cells method Homogenized lattice Boltzmann method Arbitrarily shaped particle Discrete contact model Particle-resolved simulation OpenLB

The immune modifying effects of amino acids on gut-associated lymphoid tissue

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journal of Animal Science and Biotechnology 2013年第3期4卷 195-204页

作者： Megan r ruth Catherine j Field Department of Agricultural Food and Nutritional Science 4-126A Li Ka Shing Health Research Innovation Centre University of AlbertaEdmonton AB T6G 2E1 Canada

The intestine and the gut-associated lymphoid tissue（GALT） are essential components of whole body immune defense,protecting the body from foreign antigens and pathogens,while allowing tolerance to commensal bacteria and dietary *** requirement for protein to support the immune system is well *** is known regarding the immune modifying properties of individual amino acids,particularly on the *** oral and parenteral feeding studies have established convincing evidence that not only the total protein intake,but the availability of specific dietary amino acids（in particular glutamine,glutamate,and arginine,and perhaps methionine,cysteine and threonine） are essential to optimizing the immune functions of the intestine and the proximal resident immune *** amino acids each have unique properties that include,maintaining the integrity,growth and function of the intestine,as well as normalizing inflammatory cytokine secretion and improving T-lymphocyte numbers,specific T cell functions,and the secretion of IgA by lamina propria *** understanding of this area has come from studies that have supplemented single amino acids to a mixed protein diet and measuring the effect on specific immune *** studies should be designed using amino acid mixtures that target a number of specific functions of GALT in order to optimize immune function in domestic animals and humans during critical periods of development and various disease states.

关键词： Amino acids Arginine Epithelium Glutamate Glutamine Gut-associated lymphoid tissue Intestine Mucosa

Steady vortex force theory and slender-wing flow diagnosis

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Acta Mechanica Sinica 2007年第6期23卷 609-619页

作者： Y.T.Yang r.K.Zhang Y.r.An j.Z.Wu State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China

The concept vortex force in aerodynamics is sys- tematically examined based on a new steady vortex-force theory （Wu et al., Vorticity and vortex dynamics, Springer, 2006） which expresses the aerodynamic force （and moment） by the volume and boundary integrals of the Lamb vector. In this paper, the underlying physics of this theory is explored, including the general role of the Lamb vector in non- linear aerodynamics, its initial formation, and its relevance to the total-pressure non-uniformity. As a typical example, the theory is applied to the flow over a slender delta wing at a large angle of attack. The highly localized flow structures with high Lamb-vector peaks are identified in terms of their net contribution to various constituents of the total aerody-namic force. This vortex-force diagnosis sheds new light on the flow control and configuration optimization.

关键词： Vortex force - Delta-wing - Flow control

肝细胞癌的预后:通过美国人群队列研究比较7种评分标准

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世界核心医学期刊文摘（胃肠病学分册） 2005年第8期1卷 46-47页

作者： Marrero j.A Fontana r.j Barrat A 王铮 Division of Gastr oenterology University of Michigan3912 Taubman Center Ann ArborMI 48109-0362 United StatesDr

Currently there is no consensus which staging system is best in predicting the survival of patients with hepatocellular carcinoma (HCC). The aims of this stud y were to identify independent predictors of survival and to compare 7 available prognostic staging systems in patients with HCC. A total of 239 consecutive pat ients with cirrhosis and HCC seen between january 1, 2000, and December 31, 2003 , were ***, laboratory, and tumor characteristics and performan ce status were determined at diagnosis and before *** of survival were identified using the Kaplan-Meir test and the Cox model. Sixty-two perce nt of patients had hepatitis C, 56%had more than 1 tumor nodule, 24%had portal vein thrombosis, and 29%did not receive any cancer treatment. At the time of c ensorship, 153 (63%) patients had died. The 1-and 3-year survival of the enti re cohort was 58%and 29%, respectively. The independent predictors of surviv- al were performance status (Pre greater than 10 (P = .001), p ortal vein thrombosis (P=.0001), and tumor diameter greater than 4 cm (P = .001) . Treatment of HCC was related to overall su- rvival. The Barcelona Clinic Liver Cancer(BCLC) staging system had the best in dependent predictive power for survival when compared with the other 6 prognosti c systems. In conclusion, performance status, tumor extent, liver fun- ction, and treatmentwere independent predictors of survival mostly in patients with cirrhosis and HCC. The BCLC staging system includes aspects of all of thes e elements and provided the best prognostic stratification for our cohort of pat ients with HCC.

关键词：肝细胞癌队列研究肝细胞性肝癌评分标准肿瘤进展抗癌治疗瘤结节门静脉血栓形成丙型肝炎肿瘤特征

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烟草寄生线虫及其防治

国外烟草 1990年第2期 30-32页

作者： Lal.,r.j 徐秋萍

How spiders practice aggressive and Batesian mimicry

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Current Zoology 2012年第4期58卷 620-629页

作者： Ximena j. NELSON robert r. jACKSON School of Biological Sciences University of Canterbury Private Bag 4800 Christchurch New Zealand International Centre of Insect Physiology and Ecology Thomas Odhiambo Campus EO. Box 30 Mbita Point Kenya

To understand communication, the interests of the sender and the receiver/s of signals should be considered sepa-rately. When our goal is to understand the adaptive significance of specific responses to specific signals by the receiver, questions about signal information are useful. However, when our goal is to understand the adaptive significance to the sender of generating a signal, it may be better to envisage the receiver＇s response to signals as part of the sender＇s extended phenotype. By making signals, a sender interfaces with the receiver＇s model of the world and indirectly manipulates its behaviour. This is especially clear in cases of mimicry, where animals use deceptive signals that indirectly manipulate the behaviour of receivers. Many animals adopt Batesian mimicry to deceive their predators, or aggressive mimicry to deceive their prey. We review examples from the lite-rature on spiders to illustrate how these phenomena, traditionally thought of as distinct, can become entangled in a web of lies .

关键词： Mimicry Communication Spider Deception Signal Search image

Heme oxygenase system in hepatic ischemia-reperfusion injury

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World journal of Gastroenterology 2010年第48期16卷 6068-6078页

作者： james A richards Stephen j Wigmore Luke r Devey Centre for Inflammation research The University of EdinburghThe Queen's Medical Research Institute

Hepatic ischemia-reperfusion injury (IrI) limits access to transplantation. Heme oxygenase-1 (HO-1) is a powerful antioxidant enzyme which degrades free heme into biliverdin,free iron and carbon monoxide. HO-1 and its metabolites have the ability to modulate a wide variety of inflammatory disorders including hepatic IrI. Mechanisms of this protective effect include reduction of oxygen free radicals,alteration of macrophage and T cell phenotype. Further work is required to understand the physiological importance of the many actions of HO-1 identified experimentally,and to harness the protective effect of HO-1 for therapeutic potential.

关键词： Ischemia-reperfusion injury Heme oxygenase Transplantation Ischemic pre-conditioning