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A 3D pyramid spline element

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Acta Mechanica Sinica 2011年第6期27卷 986-993页

作者： Juan chen Chong-Jun Li wan-Ji chen School of Mathematics and Quantitative Economics Dongbei University of Finance and Economics 116025 Dalian China School of Mathematical Sciences Dalian University of Technology116024 Dalian China Key Laboratory of Liaoning Province for Composite Structural Analysis of Aerocraft and Simulation Shenyang Aerospace University 110136 Shenyang China State Key Laboratory for Structural Analysis of Industrial Equipment Dalian University of Technology 116024 Dalian China

In this paper,a 13-node pyramid spline element is derived by using the tetrahedron volume coordinates and the B-net method,which achieves the second order completeness in Cartesian *** appropriate examples were employed to evaluate the performance of the proposed *** numerical results show that the spline element has much better performance compared with the isoparametric serendipity element Q20 and its degenerate pyramid element P13 especially when mesh is distorted,and it is comparable to the Lagrange element *** has been demonstrated that the spline finite element method is an efficient tool for developing high accuracy elements.

关键词： Spline finite element Pyramid element The second order completeness B-net method

One-step synthesis of FeO(OH)nanoparticles by electric explosion of iron wire underwater

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Defence Technology（防务技术） 2022年第1期18卷 133-139页

作者： Hao Yin Xin Gao Peng-wan chen Insitute of Systems Engineering China Acaderry of Engineering PhysicsMianyang.Sichuan 612900.China State Key Laboratory of Explosion Science and Technology Beijing Ins titute of Technology Beijing100081.China

In this study,we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging *** as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS),showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental *** particular,pure FeO(OH)nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 *** of discharge current and resistive voltage data indicate that the high energy input induced bystrong plasma discharge at high charging voltage is a key factor to form FeO(OH).This study presents a one-step method to synthesize FeO(OH)nanoparticles using electric explosion of iron wire.

关键词： Electric wire explosion Plasma tunnel Nanopartides FeO(OH)

Corrosion resistance of benzotriazole passivated Cu-Zn-Alshape memory alloy in artificial Ringer's solution

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Rare Metals 2005年第3期24卷 252-256页

作者： LIANG chenghao chen Bangyi chen wan wanG Hua State Key laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian 116012 China

The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole was investigated by salt spraying test and electrochemical methods in artificial Ringer＇s solution. The results showed that after benzotriazole passivation, the corrosion resistance of the Cu-Zn-Al shape memory alloy was improved evidently. The anodic polarization current density of the passivated alloy decreased, the mass loss reduced, the anodic passivation accelerated, the anodic active dissolution was inhibited effectively, and the surface tarnishing was reswained. Infrared reflection spectrum test showed that Cu（Ⅰ）-benzotriazole or Cu（Ⅱ）-benzotriazole complex layer was formed on the surface of the Cu-Zn-Al shape memory alloy after passivation. This layer appeared plane, well adhesion, and presented homogeneous golden metallic luster. The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole is improved for the formation of an electrochemical stable baffle layer on passivated surface. This layer separates the metal substrate from the outside corrosion medium effectively and retards the corrosion process of dezincification.

关键词： surface modification corrosion resistance electrochemical method Cu-Zn-Al shape memory alloy benzotriazole passivation

Effects on the Phase Transformation Temperature of Nanofluids by the Nanoparticles

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Journal of Materials Science & Technology 2008年第5期24卷 742-744页

作者： Huaqing XIE Jifen wan Lifei chen Department of Environmental Engineering Shanghai Second Polytechnic University Shanghai 201209 China

Nanofluids have been demonstrated to have intriguing thermodynamic properties. In this work, we described the investigation of the phase transformation behaviors of nanofluids containing alumina （Al2O3） or titania （TiO2） nanoparticles with different weight fractions. The experimental results indicate that the melting temperatures of nanofluids （in freezing states） are reduced with the increase of the weight fraction of nanoparticles. The reduction is related to nanoparticle species as well as nanoparticle size.

关键词： Nanofluids Thermal analysis Melting

An advanced higher-order theory for laminated composite plates with general lamination angles

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Acta Mechanica Sinica 2011年第5期27卷 720-729页

作者： Zhen Wu Hong Zhu wan-Ji chen Key Laboratory of Liaoning Province forComposite Structural Analysis of Aerocraft and Simulation Shenyang Aerospace University 110136 Shenyang China

This paper proposes a higher-order shear deformation theory to predict the bending response of the laminated composite and sandwich plates with general lamination *** proposed theory a priori satisfies the continuity conditions of transverse shear stresses at ***,the number of unknown variables is independent of the number of *** first derivatives of transverse displacements have been taken out from the inplane displacement fields,so that the C 0 shape functions are only required during its finite element *** to C 0 continuity requirements,the proposed model can be conveniently extended for implementation in commercial finite element *** verify the proposed theory,the fournode C 0 quadrilateral element is employed for the interpolation of all the displacement parameters defined at each nodal point on the composite *** results show that following the proposed theory,simple C 0 finite elements could accurately predict the interlaminar stresses of laminated composite and sandwich plates directly from a constitutive equation,which has caused difficulty for the other global higher order theories.

关键词： Laminated and sandwich composites Higherorder theory C 0 continuity requirement Transverse shear stress

The breaking of spin symmetry in the single-particle resonances in deformed nuclei

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Nuclear Science and Techniques 2024年第3期35卷 237-245页

作者： Zhen-Yu Zheng Shou-wan chen Quan Liu School of Physics and Optoelectronic Engineering Anhui UniversityHefei 230601China

The exploration of spin symmetry (SS) in nuclear physics has been instrumental in identifying atomic nucleus *** this study,we solve the Dirac equation from the relativistic mean field (RMF) in complex momentum *** investigated SS and its breaking in single-particle resonant states within deformed nuclei,with a focus on the illustrative *** was the initial discovery of a resonant spin doublet in a deformed nucleus,with the expectation of the SS approaching the continuum *** increasing single-particle energy,the splitting of the resonant spin doublets widened *** escalating splitting implies diminishing adherence to the SS,indicating a departure from the expected behavior as the energy levels *** also analyzed the width of the resonant states,showing that lower orbital angular momentum resonances possess shorter decay times and that SS is preserved within broad resonant doublets,as opposed to narrow resonant *** the radial density of the upper components for the bound-state and resonant-state doublets,it becomes evident that while SS is well-preserved in the bound states,it deteriorates in the resonant *** impact of nuclear deformation (β_(2)) on SS was examined,demonstrating that an increase in β_(2) resulted in higher energy and width splitting in the resonant spin doublets,which is attributed to increased component ***,the sensitivity of spin doublets to various potential parameters such as surface diffuseness (a),radius (R),and depth (Σ0) is discussed,emphasizing the role of these parameters in *** study provides valuable insights into the behavior of spin doublets in deformed nuclei and their interplay with the nuclear structure,thereby advancing our understanding of SS in the resonance state.

关键词： Spin symmetry Resonant states Deformed nuclei Complex-momentum representation

Ruin Probability and Joint Distributions of Some Actuarial Random Vectors in the Compound Pascal Model

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Acta Mathematicae Applicatae Sinica 2011年第1期27卷 63-74页

作者： Xian-min Geng Shu-chen wan College of Science Nanjing University of Aeronautics & Astronautics Nanjing 210016 China

The compound negative binomial model, introduced in this paper, is a discrete time version. We discuss the Markov properties of the surplus process, and study the ruin probability and the joint distributions of actuarial random vectors in this model. By the strong Markov property and the mass function of a defective renewal sequence, we obtain the explicit expressions of the ruin probability, the finite-horizon ruin probability, the joint distributions of T, U（T - 1）, ｜U（T）｜ and inf U（n）（i.e., the time of ruin, the surplus immediately before ruin, the deficit at ruin and maximal deficit from ruin to recovery） and the distributions of some actuarial random vectors.

关键词： Compound negative binomial model Ruin probability Sequence of up-crossing zero points,Ultimately leaving deficit time Joint distributions

Microscopic Superconductivity and Room Temperature Electronics of High-T_c Cuprates

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Communications in Theoretical Physics 2008年第11期50卷 1237-1240页

作者： LIU Fu-Su chen wan-Fang Department of Physics Peking University Beijing 100871 China Graduate School Chinese Academy of Sciences Beijing 100080 China

Abstract This paper points out that the Landau criterion for macroscopic superfluidity of He H is only a criterion for microscopic superfluidity of ^4He, extends the Landau criterion to microscopic superconductivity in fermions （electron and hole） system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-To cuprates.

关键词： superconductivity Landau criterion long-range phase coherence

Synthesis and Structural Characterization of Di(2-amino-5-methyl-1,8-naphthyridin-1-ium-7-carboxylato)dichlorocuprate(Ⅱ) Dihydrate

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Chinese Journal of Structural Chemistry 2007年第3期26卷 287-290页

作者： JIN Shou-Wen LIU Bin chen wan-Zhi Department of Chemistry Zhejiang University Xixi Campus Hangzhou 310028 China

Di（2-amino-5-methyl-1,8-naphthyridin-1-ium-7-carboxylato）dichlorocuprate（Ⅱ） di- hydrate has been prepared from 5,7-dimethyl-1,8-naphthyridine-2-amine, CuCl2·2H2O and concentrated hydrochloride acid, and its structure was determined by X-ray diffraction at 298 K. The compound （C20H22Cl2CuN6O6, Mr = 576.88） crystallizes in monoclinic, space group P21/n with a = 9.102（9）, b = 12.150（12）, c = 10.619（10） A,β = 91.20°, V= 1174.1（19） A^3, Z= 2, Dc= 1.632 g/cm^3, F（000） = 590,μ = 1.208 mm^-1, R = 0.0392 and wR = 0.0984. The Cu^2＋ ion is six-coordinated by two nitrogen and two oxygen atoms from two different naphthyridine ligands at the equatorial positions together with two chloride ions located at the axial positions.

关键词： crystal structure copper chloride 5,7-dimethyi-1,8-naphthyridine-2-amine