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Characterization for elastic constants of fused deposition modelling-fabricated materials based on the virtual fields method and digital image correlation

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Acta Mechanica Sinica 2017年第6期33卷 1075-1083页

作者： Quankun Cao Huimin xie AML Department of Engineering Mechanics Tsinghua University Beijing 100084 China

Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?.

关键词： Fused deposition modelling Virtual fields method Digital image correlation Orthotropic constitutive model Disk compression

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Atmospheric mercury over the marine boundary layer observed during the third China Arctic Research Expedition

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Journal of Environmental Sciences 2011年第9期23卷 1424-1430页

作者： Hui Kang Zhouqing xie Institute of Polar Environment University of Science and Technology of China Hefei 230026 China

TGM measurements on board ships have proved to provide valuable complementary information to measurements by a ground based monitoring *** the third China Arctic Research Expedition （from July 11 to September 24,2008）,TGM concentrations over the marine boundary layer along the cruise path were in-situ measured using an automatic mercury vapor *** we firstly reported the results in Japan Sea,North Western Pacific Ocean and Bering Sea,where there are rare *** value ranged between 0.30 and 6.02 ng/m 3 with an average of （1.52 ± 0.68） ng/m 3 ,being slightly lower than the background value of Northern Hemisphere （1.7 ng/m 3 ）.Notably TGM showed considerably spatial and temporal ***,the average value of TGM in Bering Sea was higher than those observed in Japan Sea and North Western Pacific *** the north of Japan Sea TGM levels were found to be lower than 0.5 ng/m 3 during forward cruise and displayed obviously diurnal cycle,indicating potential oxidation of gaseous mercury in the *** pronounced episode was recorded as *** levels of TGM were observed in the coastal regions of southern Japan Sea during backward cruise due primarily to air masses transported from the adjacent mainland reflecting the contribution from anthropogenic *** ship returned back and passed through Kamchatka Peninsula TGM increased by the potential contamination from volcano emissions.

关键词： total gaseous mercury atmosphere marine boundary layer Japan Sea North Western Pacific Ocean Bering Sea

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Variational Corner Transfer Matrix Renormalization Group Method for Classical Statistical Models

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Chinese Physics Letters 2022年第6期39卷 65-70页

作者： X.F.Liu y.F.Fu W.Q.yu J.F.yu Z.y.xie Department of Physics Renmin University of ChinaBeijing 100872China School of Physics and Electronics Hunan UniversityChangsha 410082China

In the context of tensor network states,we for the first time reformulate the corner transfer matrix renormalization group(CTMRG)method into a variational bilevel optimization *** solution of the optimization problem corresponds to the fixed-point environment pursued in the conventional CTMRG method,from which the partition function of a classical statistical model,represented by an infinite tensor network,can be efficiently *** validity of this variational idea is demonstrated by the high-precision calculation of the residual entropy of the dimer model,and is further verified by investigating several typical phase transitions in classical spin models,where the obtained critical points and critical exponents all agree with the best known results in *** extension to three-dimensional tensor networks or quantum lattice models is straightforward,as also discussed briefly.

关键词： tensor variational straight

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FRECKLE FORMATION AND CHARACTERIZATION OF A Ni-Cr-Mo-Fe-W ALLOy

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 414-418页

作者： J.X.Dong M.C.Zhang y.P.Zeng X.S.xie University of Science and Technology Beijing Beijing 100083 ChinaUniversity of Science and Technology Beijing Beijing 100083 ChinaUniversity of Science and Technology Beijing Beijing 100083 ChinaUniversity of Science and Technology Beijing Beijing 100083 China

The freckle formation and their phase characterization in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in a Ni-Cr-Mo-Fe-W alloy. These results show that in freckle areas a large number of M6C, μ and P phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and C during solidification, which results in small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give an reasonable interpretation of the freckle feature for this alloy.

关键词： freckle Ni-Cr-Mo-Fe- W alloy thermodynamic calculation

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A STUDy OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

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Acta Metallurgica Sinica(English Letters) 2007年第1期20卷 27-34页

作者： X.B. Li y.Q. xie y.Z. Nie H.J. Peng H.J. Tao F.X. yu College of Materials Science and Engineering Central South University Changsha 410083 China

On the basis of energy and shape method for the determination of the valence bond （ VB ） structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is ec^29907. （sc^0.4980 ＋ dc^2.4927） ef^1.0098 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.

关键词： valence bond structure temperature titanium

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Continuous Selection,Collectively Fixed Points and System of Coincidence Theorems in Product Topological Spaces

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Acta Mathematica Sinica,English Series 2006年第6期22卷 1629-1638页

作者： xie Ping DIng College of Mathematics and Software Science Sichuan Normal University Chengdu 610066 P. R. China

Some new continuous selection theorems are first proved in noncompact topological spaces. As applications, some new collectively fixed point theorems and coincidence theorems for two families of set-valued mappings defined on product space of noncompact topological spaces are obtained under very weak assumptions. These results generalize many known results in recent literature.

关键词： continuous selection collectively fixed point coincidence theorem for two families of set-valued mappings FC-space

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Gas-assisted microfluidic step-emulsification forgenerating micron- and submicron-sized droplets

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Microsystems & Nanoengineering 2023年第4期9卷 167-179页

作者： Biao Huang Xinjin Ge Boris y.Rubinstein Xianchun Chen Lu Wang Huiy.ng xie Alexander M.Leshansky Zhenzhen Li Department of Aerospace Engineering Beijing Institute of TechnologyNo.5 ZhongGuanCunNan StreetHaiDian DistrictBeijing 100081China State Key Laboratory of Engines Tianjin UniversityNo.92 Weijin RoadNankai DistrictTianjin 300350China Stowers Institute for Medical Research Kansas CityMO 64110USA School of Chemistry and Chemical Engineering Beijing Institute of TechnologyNo.5 ZhongGuanCunNan StreetHaiDian DistrictBeijing 100081China Department of Chemical Engineering Technion–Israel Institute of TechnologyHaifa 32000Israel

Micron- and submicron-sized droplets have extensive applications in biomedical diagnosis and drug ***, accurate high-throughput analysis requires a uniform droplet size distribution and high production *** the previously reported microfluidic coflow step-emulsification method can be used to generate highlymonodispersed droplets, the droplet diameter (d) is constrained by the microchannel height (b), d\3b, while theproduction rate is limited by the maximum capillary number of the step-emulsification regime, impedingemulsification of highly viscous liquids. In this paper, we report a novel, gas-assisted coflow step-emulsificationmethod, where air serves as the innermost phase of a precursor hollow-core air/oil/water emulsion. Air graduallydiffuses out, producing oil droplets. The size of the hollow-core droplets and the ultrathin oil layer thickness bothfollow the scaling laws of triphasic step-emulsification. The minimal droplet size attains d 1:7b, inaccessible instandard all-liquid biphasic step-emulsification. The production rate per single channel is an order-of-magnitudehigher than that in the standard all-liquid biphasic step-emulsification and is also superior to alternative emulsificationmethods. Due to low gas viscosity, the method can also be used to generate micron- and submicron-sized droplets ofhigh-viscosity fluids, while the inert nature of the auxiliary gas offers high versatility.

关键词： sized viscosity generating

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MOLECULAR　MECHANICAL　AND　QUANTUM　CHEMICAL　CALCULATION　ON　ACyLATION　REACTIVITy　FOR　1－（NITRO　SUBSTITUTED　ANILINO）－4－SUBSTITUTED－2，6－PIPERAZINEDIONES

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Chinese Chemical Letters 1995年第8期6卷 691-694页

作者： Jiang, HL Li, Q Chen, KX Tang, y Shen, X Ji, Ry xie, yy Chinese Acad Sci Shanghai Inst Mat Med Shanghai 200031 Peoples R China

Molecular mechanical and quantum chemical methods were used to calculate the conformational and electronic structures of the template molecules of (nitro substituted an ill no)-4 - sub st nut ed -2, 6 -piperazinediones, With the calculation results we explained the acylation reactivity of title compounds satisfactorily.

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New Generalized R-KKM Type Theorems in General Topological Spaces and Applications

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Acta Mathematica Sinica,English Series 2007年第10期23卷 1869-1880页

作者： xie Ping DIng College of Mathematics and Software Science Sichuan Normal University Chengdu 610066 P. R. China

In this paper, some new generalized R-KKM type theorems for generalized R-KKM mappings with finitely closed values and with finitely open values are established in noncompact topological spaces without any convexity structure under much weaker assumptions. As applications, some new minimax inequalities, saddle point theorem and equilibrium existence theorem for equilibrium problems with lower and upper bounds are established in general noncompact topological spaces. These theorems unify and generalize many known results in the literature.

关键词： generalized R-KKM mapping finitely closed-valued (open-valued) generalized R-KKM type theorem minimax inequality saddle point equilibrium problem

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Behavior of Theta-series under Modular Substitutions

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Acta Mathematica Sinica,English Series 2011年第9期27卷 1705-1716页

作者： Bing y.ng xie LMAM School of Mathematical Science Peking University Beijing 10087'1 P. R. China

In this article we provide a transformation formula of certain theta series, and apply it to obtain non-holomorphic vector-valued modular forms.

关键词： Theta series nonholomorphic vector-valued modular forms

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