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Numerical Study on the Stress–Strain Cycle of Thermal Self-Compressing Bonding

Chinese Journal of Mechanical Engineering 2018年第4期31卷 140-147页

作者： yun-Hua Deng Qiao guan Jun tao Bing Wu Aeronautical Key Laboratory for Welding and Joining Technologies AVIC Beijing Aeronautical Manufacturing Technology Research Institute School of Mechanical Engineering and Automation Beihang University Science and Technology on Power Beam Process Laboratory AVIC Beijing Aeronautical Manufacturing Technology Research Institute

Thermal self-compressing bonding(TSCB) is a new solid-state bonding method pioneered by the authors. With electron beam as the non-melted heat source, previous experimental study performed on titanium alloys has proved the feasibility of TSCB. However, the thermal stress–strain process during bonding, which is of very important significance in revealing the mechanism of TSCB, was not analysed. In this paper, finite element analysis method is adopted to numerically study the thermal elasto-plastic stress–strain cycle of thermal self-compressing bonding. It is found that due to the localized heating, a non-uniform temperature distribution is formed during bonding, with the highest temperature existed on the bond interface. The expansion of high temperature materials adjacent to the bond interface are restrained by surrounding cool materials and rigid restraints, and thus an internal elasto-plastic stress–strain field is developed by itself which makes the bond interface subjected to thermal compressive action. This thermal self-compressing action combined with the high temperature on the bond interface promotes the atom diffusion across the bond interface to produce solid-state joints. Due to the relatively large plastic deformation, rigid restraint TSCB obtains sound joints in relatively short time compared to diffusion bonding.

关键词： Thermal self-compressing bonding Locally non-melted heating Thermal elasto-plastic stress–strain Atom diffusion Solid-state bonding Finite element analysis

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Chiral emission and Purcell enhancement in a hybrid plasmonic-photonic microresonator

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Light(Science & Applications) 2020年第1期9卷 1961-1962页

作者： Qi-tao Cao You-Ling Chen yun-Feng Xiao Frontiers Science Center for Nano-optoelectronics&School of Physics Peking UniversityBeijing 100871China State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China

A high-Q hybrid plasmonic-photonic microresonator,which consists of a dielectric microdisk hybridized with a plasmonic nanoantenna dimer,enables an enlarged local density of states of the optical field and chiral prop... 详细信息

关键词： cavity plasmon Chiral

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Study of the Dynamic Characteristics of A Cone-Shaped Recovery System on Submarines for Recovering Autonomous Underwater Vehicle

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China Ocean Engineering 2020年第3期34卷 387-399页

作者： MENG Ling-shuai LIN Yang gu Hai-tao SU Tsung-Chow State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China Florida Atlantic University Boca RatonFL 33431USA

National navies equip their submarines with Autonomous Underwater Vehicle(AUV)*** has become an important component of submarine development in technologically-advanced *** advanced and reliable recovery systems directly improves the safety and operational efficiency of submarines equipped with *** this paper,based on aerial refueling technology,a cone-shaped recovery system with two different guiding covers(closed structure and frame structure)is applied to the *** taking the Suboff model as the research object,STAR-CCM was used to study the influence of the installation position of the recovery system,and the length of the rigid rod,on the Suboff *** was found that when the recovery system is installed in the middle and rear of the Suboff model at the same velocity and the same length of the rigid rod,the Suboff model has the good stability and less *** experiences the largest drag when being installed in the front of the rigid ***,when the recovery system is installed in the front and middle of the rigid rod,the drag increases as its length increases,and the lift decreases as its length *** with the closed structure guiding cover,the Suboff model will have less drag and better stability when the recovery system uses the frame structure guiding ***,the deflection and vibration of the rigid rod were also analyzed via mathematical theory.

关键词： cone-shaped recovery system submarine computational fluid dynamics(CFD) hydrodynamics deflection vibration

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A Unified Theoretical Treatment on Statistical Properties of the Semi-batch Self-condensing Vinyl Polymerization System

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Chinese Journal of Polymer Science 2021年第11期39卷 1510-1520页

作者： Fang gu Jiang-tao Li Xiao-Zhong Hong Hai-Jun Wang College of Chemistry and Environment Science Hebei UniversityBaoding 071002China College of Physical Science and Technology Hebei UniversityBaoding 071002China Chemical Biology Key Laboratory of Hebei Province Hebei UniversityBaoding 071002China Key Laboratory of Medicinal Chemistry and Molecular Diagnosis Ministry of EducationHebei UniversityBaoding 071002China

We present a novel generating function(GF)method for the self-condensing vinyl polymerization(SCVP)system with any initial distribution of preexisted *** a method was proven to be especially useful to investigate the semi-batch SCVP system allowing a sequence of feeding operations during the ***,the number-,weight-,and z-average molecular weights as well as dispersity index of hyperbranched polymers can be explicitly given,which are determined by predetermined feeding details and conversions in each polymerization *** analytical results are further confirmed by the corresponding Monte Carlo ***,the present GF method has provided a unified treatment to the semi-batch SCVP ***,hyperbranched polymers with desired properties can be prepared by designing feeding details and presetting conversions at each step based on the present GF method.

关键词： Self-condensing vinyl polymerization Semi-batch Generating function Statistical properties

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Trapping photons with optical black hole

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Light(Science & Applications) 2023年第4期12卷 507-508页

作者： You-Ling Chen Qi-tao Cao yun-Feng Xiao State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Frontiers Science Center for Nano-optoelectronics&School of Physics Peking UniversityBeijing 100871China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006 ShanxiChina

An optical black-hole cavity based on transformation optics enables Q-factor enhancement and strong field confinement,by eliminating the intrinsic radiation loss of the conventional whispering-gallery modes,holding po... 详细信息

关键词： optics eliminating enable

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Theoretical Study of Reaction Mechanism of 1-Propenyl Radical with NO

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Chinese Journal of Chemical Physics 2008年第3期21卷 239-244页

作者： Xue-li Cheng Yan-yun Zhao Feng Li Ren-tao Wu Department of Chemistry Taishan University Tai'an 271021 China Department of Chemistry Qufu Normal University Qufu 273155 China Department of Physics Taishan University Tai'an 271021 China

The reaction system of 1-propenyl radical with NO is an ideal model for studying the intermolecular and intramolecular reactions of complex organic free radicals containing C=C double bonds. On the basis of the full optimization of all species with the Gaussian 98 package at the B3LYP/6- 311＋＋G^＊＊ level, the reaction mechanism was elucidated extensively using the vibrational mode analysis. There are seven reaction pathways and five sets of small molecule end products： CH2O＋CH3CN, CH2CHCN＋H2O, CH3CHO＋HCN, CH3CHO＋HNC, and CH3CCH＋HNO. The channel of C3H5-＋NO→IM1→TS1→IM2→TS2→IM3→TS3→CH3CHO＋HCN is thermodynamically most favorable.

关键词： Reaction mechanism 1-Propenyl radical NO Vibrational mode analysis

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Numerical Study on Motion Responses of Two Parallel Ships During Underway Replenishment by the Semi-Analytical HOTP Method

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China Ocean Engineering 2022年第2期36卷 233-246页

作者： YANG yun-tao ZHU Ren-chuan MA Chao GAO Hui School of Naval Architecture and Civil Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600China State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea ExplorationSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of High Performance Ship Technology(Wuhan University of Technology) Ministry of EducationWuhan 430063China School of Naval Architecture Ocean and Energy Power EngineeringWuhan University of TechnologyWuhan 430063China

Motion responses of two ships advancing parallel in waves with hydrodynamic interactions are investigated in this paper. Within the framework of the frequency-domain potential flow theory, a semi-analytical higher-order translating-pulsating source(HOTP) method is presented to solve the problems of coupled radiation and diffraction potential. The method employs nine-node bi-quadratic curvilinear elements to discretize the boundary integral equations(BIEs) constructed over the mean wetted surface of the two ship hulls. In order to eliminate the numerical oscillation, analytical quadrature formulas are derived and adopted to evaluate the integrals related to the Froudedependent part of the Green’s function along the horizontal direction in the BIEs. Based on the method, a numerical program is originally coded. Through the calculations of hydrodynamic responses of single ships, the numerical implementation is proved successful. Then the validated program is applied in the investigations on the hydrodynamic interactions of two identical Wigley Ⅲ hulls and the underway replenishment of a frigate and a supply ship in waves with and without stagger, respectively. The comparison between the present computed results with experimental data and numerical solutions of other methods shows that the semi-analytical HOTP method is of higher accuracy than the pulsating source Green’s function method with speed correction and better stability than the traditional HOTP method based on Gauss quadrature. In addition, for two ships with obviously different dimensions,the influence of hydrodynamic interactions on the smaller ship is found to be more noticeable than that on the larger ship, which leads to the differences between the motions of frigate with and without the presence of supply ship.

关键词： semi-analytical HOTP method two parallel ships underway replenishment coupled motions

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Unraveling the electrocatalytically active sites and stability of Co&Co oxides on nanocarbon for oxygen evolution reaction in acid solution

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Journal of Energy Chemistry 2020年第10期29卷 8-13页

作者： Yansong Zhu Tianran Zhang tao An yun Zong Jim Yang Lee Faculty of Pharmacy Shenyang Pharmaceutical UniversityShenyang 110016LiaoningChina Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore Institute of Materials Research and Engineering(IMRE) Singapore

The oxygen evolution reaction(OER)in acid solution is a significant challenge for non-precious metal electrocatalysts based on the transition metals although they have shown good OER performance in alkaline *** this study,we synthesized the electrocatalysts containing two or three Co species(Co,CoO and Co3O4)nanoparticles on porous graphitic carbon(PGC)nanosheets which were prepared by a facile and low-cost synthesis where Co(NO3)2•6H2O and glucose were pyrolyzed in the presence of sodium chloride *** Co3O4-dominated catalyst as-prepared,Co3O4/PGC,is OER active in acid solution(1.74 V at a current density of 10 mA cm^−2).We identified the OER active sites in the catalyst to be the Co3O4 nanoparticles rather than carbon-coated *** comparative studies of the varied catalysts,we also proved that Co3O4 is catalytically more active than Co and *** Co3O4/PGC catalyst,however,lost almost of all its activity after 100 voltammetric cycles in the 1.2-1.8 V voltage *** the catalyst stability was examined potentiostatically at different potentials,the catalyst showed good stability at 1.4 *** stability study also revealed the mechanism of the catalyst instability in acid was caused by Co3O4 reduction below 1.4 V and by Co3O4 oxidation above 1.4 V.1.4 V is therefore a unique potential where Co3O4 nanoparticles are neither oxidized nor reduced to be susceptible to acid dissolution.

关键词： Non-precious metal Active sites Oxygen evolution reaction Acid Stability

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Role of Microalloyed Y and Gd in Improving the Corrosion Resistance of Rolled Mg-3Al-1Zn Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第6期35卷 941-947页

作者： Panpan Wang Haitao Jiang Yujiao Wang yun Zhang Jingchao tao Shanghai Key Laboratory of Materials Laser Processing and Modification and National Engineering Research Center of Light Alloy Net FormingSchool of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Institute of Engineering Technology University of Science and TechnologyBeijingBeijing 100083China

The corrosion performances of rolled AZ31 alloy with addition of Y and Gd were comparatively investigated. The corrosion rates of AZ31 alloy modified with Y and Gd were 3.3 and 3.7 mm/y immersing for 24 h in 3.5 wt% NaCl solution, respectively, which were much lower than that of AZ31 alloy(23.6 mm/y). The remarkable improvement in corrosion performance by adding Y or Gd was ascribed to preferentially form less noble Al_(2)Y or Al_(6)GdMn_(6) and more protective corrosion product layer, resulting in the reduction in H_(2) evolution rate and the enhancement of passivity.

关键词： AZ31 alloy Second phases Volta potential diff erence Y Gd

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Search for d-MPs without duplicates in two-terminal multistate networks based on MPs

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Journal of Systems Engineering and Electronics 2022年第6期33卷 1332-1341页

作者： XU Bei FANG Yining BAI guanghan ZHANG yun’an tao Junyong Laboratory of Science and Technology on Integrated Logistics Support College of Intelligent Sciences and TechnologyNational University of Defense TechnologyChangsha 410073China School of General Aviation Nanchang Hangkong UniversityNanchang 330063China

The reliability evaluation of a multistate network is primarily based on d-minimal paths/cuts(d-MPs/d-MCs).However,being a nondeterminism polynomial hard(NP-hard)problem,searching for all d-MPs is a rather challenging *** existing implicit enumeration algorithms based on minimal paths(MPs),duplicate d-MP candidates may be *** extra step is needed to locate and remove these duplicate d-MP candidates,which costs significant computational *** paper proposes an efficient method to prevent the generation of duplicate d-MP candidates for implicit enumeration algorithms for ***,the mechanism of generating duplicate d-MP candidates in the implicit enumeration algorithms is ***,a direct and efficient avoiding-duplicates method is ***,an improved algorithm is developed,followed by complexity analysis and illustrative *** on the computational experiments comparing with two existing algorithms,it is found that the proposed method can significantly improve the efficiency of generating d-MPs for a particular demand level d.

关键词： reliability multistate network d-minimal path(d-MP) duplicate

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