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Decomposition behavior of yttria-stabilized zirconia and its effect on directed energy deposited Ti-based composite material

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Journal of Materials Science & Technology 2022年第17期112卷 138-150页

作者： Gwanghyo Choi Won Seok Choi Yoon Sun Lee Dahye Kim Ji Hyun Sung Seungjun An Chang-Seok Oh Amine Hattal Madjid Djemai Brigitte Bacroix guy dirras Pyuck-Pa Choi Department of Materials Science and Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea 3D Additive Manufacturing Application Tech.Center Korea Institute of Industrial TechnologyDaegu 42994Republic of Korea InssTek Co. Daejeon 04763Republic of Korea Korea Institute of Materials Science 797 ChangwondaeroChangwon 51508Republic of Korea UniversitéSorbonne Paris Nord Laboratoire des Sciences des Procédés et des MatériauxLSPMCNRSUPR 3407F-93430VilletaneuseFrance Z3Dlab Parc Technologique26 Rue des SablonsMontmagny 95360France CNRS UPR3407Laboratoire des Sciences des Procédés et des MatériauxLSPMUniversitéSorbonne Paris NordF-93430VilletaneuseFrance

We report on the microstructure and the strengthening mechanisms of additively manufactured parts fabricated by directed energy deposition of Ti-6Al-4V(Ti64)powders blended with yttria-stabilized zirconia(YSZ)*** specimens showed refined microstructures as compared to bare as-deposited Ti64,where theαand columnar priorβgrain sizes decreased with increasing YSZ *** YSZ nanoparticles decomposed during the deposition process and led to the formation of yttrium oxide and some excess oxygen in the Ti64 *** decrease in the sizes of the priorβgrains could be attributed to the increasing amount of dissolved oxygen and yttrium,which promoted constitutional ***,the reduction in the size of theαgrains could be ascribed to a shift of the onset of theβ→α+βtransformation to a higher temperature and shorter time with increasing concentration of dissolved ***,the contributions of the underlying strengthening mechanisms for the as-deposited specimens were quantitatively determined.

关键词： Additive manufacturing Directed energy deposition Metal matrix composites Titanium alloys Yttrium-stabilized zirconia

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The multi-functional aspect of scanning holographic microscopy: a review(Invited Paper)

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Chinese Optics Letters 2009年第12期7卷 1066-1071页

作者： guy Indebetouw Physics Department Virginia Tech Blacksburg

Recent developments in scanning holographic microscopy that offer the prospects of new quantitative tools and imaging modalities in bio, micro, and nano sciences are reviewed. The versatility of the method is emphasized. Scanning holography can operate in an incoherent mode for fluorescence imaging, in a coherent mode for quantitative phase imaging, or in a tomographic mode for axial sectioning and rejection of the out-of-focus haze. Possible applications are illustrated with examples, and future prospects are discussed.

关键词： The multi-functional aspect of scanning holographic microscopy a review

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An Approach to Differential Geometry of Fractional Order via Modified Riemann-Liouville Derivative

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Acta Mathematica Sinica,English Series 2012年第9期28卷 1741-1768页

作者： guy JUMARIE Department of Mathematics University of Quebec at Montreal

In order to cope with some difficulties due to the fact that the derivative of a constant is not zero with the commonly accepted Riemann-Liouville definition of fractional derivative, one （Jumarie） has proposed recently an alternative referred to as （local） modified Riemann-Liouville definition, which directly, provides a Taylor＇s series of fractional order for non differentiable functions. We examine here in which way this calculus can be used as a framework for a differential geometry of fractional or- der. One will examine successively implicit function, manifold, length of curves, radius of curvature, Christoffel coefficients, velocity, acceleration. One outlines the application of this framework to La- grange optimization in mechanics, and one concludes with some considerations on a possible fractional extension of the pseudo-geodesic of thespecial relativity and of the Lorentz transformation.

关键词： Fractional calculus modified Riemann-Liouville derivative fractional Taylor's series fractional manifold fractional geodesic fractional mechanics Lorentz transformation

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Weighted Bergman kernels and virtual Bergman kernels

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Science China Mathematics 2005年第Z1期48卷 225-237页

作者： guy Roos Nevski Prospekt 113/4-53 191024 St Petersburg Russian Federation

We introduce the notion of virtual Bergman kernel and study some of its applications.

关键词： Bergman kernel, weighted Bergman kernel, virtual Bergman kernel.

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New classes of domains with explicit Bergman kernel

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Science China Mathematics 2004年第3期47卷 352-371页

作者： Roos guy Henan University Kaifeng 475001 China Nevski Prospekt 113/4-53 191024 St Petersburg Russian Federation

We introduce two classes of egg type domains, built on general boundedsymmetric domains, for which we obtain the Bergman kernel inexplicit formulas. As an auxiliary tool, we compute the integralof complex powers of the generic norm on a bounded symmetricdomains using the well-known integral of Selberg. Thisgeneralizes matrix integrals of Hua and leads to a specialpolynomial with integer or half-integer coefficients attached toeach irreducible bounded symmetric domain.

关键词： Cartan domain, Bergman kernel, holomorphic automorphism group, boundedsymmetric domain, Hua integral.

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The advantages of Low Pressure Carburizing in the Heat Treatment Subcontracting Business

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材料热处理学报 2004年第5期25卷 364-369页

作者： guy PRUNEL Bruno STAUDER BODYCOTE Chassieu FranceBODYCOTE Chassieu France

Low Pressure Carburizing (LPC) was introduced in the 90’s in the western Europe Heat Treatment business, mainly for in-house applications where it was especially appreciated for Carburizing of transmission parts. However the success of the LPC units installed for gears Carburizing in the automotive industry has hindered the development of the process in other fields - like subcontracting business -, where its advantages deserve to be enlightened. After a brief review of the principle of the process, the interest of its classical application to transmission parts is described, underlining peculiarly the reduction of the distortion observed when LPC is associated with high pressure gas quenching. Then the less-known advantages of the LPC process, like the high accuracy and reproducibility of the results, the modeling possibility and the simulation easiness, the case-depth uniformity and the full flexibility of the units are considered, showing how they can be beneficial to subcontracting business.

关键词：低压渗碳热处理转包商业 LPC 应用

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Coal pillar design when considered a reinforcement problem rather than a suspension problem

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International Journal of Mining Science and Technology 2018年第1期28卷 11-19页

作者： Russell Frith guy Reed Mine Advice Pty Ltd New South Wales 2282Australia

Current coal pillar design is the epitome of suspension design.A defined weight of unstable overburden material is estimated, and the dimensions of the pillars left behind are based on holding up that material to a prescribed factor of *** principle, this is no different to early roadway roof support ***, for the most part, roadway roof stabilisation has progressed to reinforcement, whereby the roof strata is assisted in supporting *** is now the mainstay of efficient and effective underground coal *** and reinforcement are fundamentally different in roadway roof stabilisation and lead to substantially different requirements in terms of support hardware characteristics and their *** suspension, the primary focus is the total load-bearing capacity of the installed support and ensuring that it is securely anchored outside of the unstable roof *** contrast, reinforcement recognises that roof de-stabilisation is a gradational process with ever-increasing roof displacement magnitude leading to ever-reducing *** roof support characteristics relate to such issues as system stiffness, the location and pattern of support elements and mobilising a defined thickness of the immediate roof to create(or build) a stabilising strata *** objective is to ensure that horizontal stress is maintained at a level that prevents mass roof *** paper presents a prototype coal pillar and overburden system representation where reinforcement, rather than suspension, of the overburden is the stabilising mechanism via the action of in situ horizontal *** roadway roof reinforcement principles can potentially be applied to coal pillar design under this *** merit of this is evaluated according to failed pillar cases as found in a series of published *** on the findings, a series of coal pillar system design considerations for bord and pillar type mine workings are ***

关键词： Coal pillar design Overburden stability Rock reinforcement Bord and pillar mining

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Structure and properties of graphullerene: a semiconducting two-dimensional C_(60) crystal

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npj Computational Materials 2023年第1期9卷 197-202页

作者： Uri Argaman guy Makov Dept.of Materials Engineering Ben-Gurion University of the NegevBeer-ShevaIsrael

Graphullerene is a recently discovered,two-dimensional allotrope of carbon formed from C_(60) *** has been synthesized in the form(C_(60)Mg4)n and subsequently transformed into(C_(60))n by removal of the Mg *** initio calculations are employed to examine the structure and properties of this ***,graphullerene is composed of strained C_(60) *** of these molecules is connected to six neighbors in a hexagonal network with a total of eight chemical *** find this structure to be meta-stable,owing to the strain produced by the covalent bonding of the ***,the inclusion of Mg atoms transforms the cohesion energy from negative to positive values by forming additional C-Mg bonds,creating an energetically stable *** the absence of Mg,this allotrope is a pure carbon semiconductor with an indirect band *** spectrum calculations confirm the dynamical stability of the material and yield its in-and out-of-plane sound *** addition,symmetry breaking of the C_(60) molecules results in a distribution of bond lengths and creates vibrational modes that serve as a signature of graphullerene.

关键词： material bonds crystal

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Limitations and potential design risks when applying empirically derived coal pillar strength equations to real-life mine stability problems

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International Journal of Mining Science and Technology 2019年第1期29卷 17-25页

作者： Russell Frith guy Reed Mine Advice Pty Ltd

The method of determining coal pillar strength equations from databases of stable and failed case histories is more than 50 years old and has been applied in different countries by different researchers in a range of mining situations. While common wisdom sensibly limits the use of the resultant pillar strength equations and methods to design scenarios that are consistent with the founding database, there are a number of examples where failures have occurred as a direct result of applying empirical design methods to coal pillar design problems that are inconsistent with the founding database. This paper explores the reasons why empirically derived coal pillar strength equations tend to be problem-specific and should be considered as providing no more than a pillar strength ‘‘index." These include the non-consideration of overburden horizontal stress within the mine stability problem, an inadequate definition of supercritical overburden behavior as it applies to standing coal pillars, and the non-consideration of overburden displacement and coal pillar strain limits. All of which combine to potentially complicate and confuse the back-analysis of coal pillar strength from failed cases. A modified coal pillar design representation and model are presented based on coal pillars acting to reinforce a horizontally stressed overburden, rather than suspend an otherwise unstable self-loaded overburden or section, the latter having been at the core of historical empirical studies into coal pillar strength and stability.

关键词： Coal pillar design Pillar strength Overburden mechanics Limitations of pillar design

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Helicobacter pylori infection causes gastric cancer? A review of the epidemiological,meta-analytic, and experimental evidence

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World Journal of Gastroenterology 2006年第19期12卷 2991-2999页

作者： guy D Eslick School of Public Health The University of Sydney SydneyNew South WalesAustralia Department of Medicine The University of SydneyNepean HospitalPenrithNew South WalesAustralia

Since the discovery of Carnpylobacter-like organisms （Helicobacter pylori） more than two decades ago the possibility of a relationship with gastric cancer has been postulated, tested and supposedly proven. There have been numerous human studies of various designs from many countries around the world. Several meta-analyses have been published and more recently a small number of experimental animal studies were reported looking at the association between Helicobacter pylori infection and gastric cancer. Over the years, the human epidemiological studies have produced conflicting results; the metaanalyses have as one would expect produced similar pooled estimates; while the early experimental animal studies require replication. The exact mechanisms by which H pylori might cause gastric cancer are still under investigation and remain to be elucidated.

关键词： Helicobacter pylori Gastric cancer Metaanalysis Systematic review

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