摘要：
In this paper, based on the two-potential approach combining with the isospin dependent nuclear potential, we systematically compare the α preformation probabilities of odd-A nuclei between nuclear isomeric states and ground states. The results indicate that during the process of α particle preforming, the low lying nuclear isomeric states are similar to ground states. Meanwhile, in the framework of single nucleon energy level structure, we find that for nuclei with nucleon number below the magic numbers, the α preformation probabilities of high-spin states seem to be larger than low ones. For nuclei with nucleon number above the magic numbers, the α preformation probabilities of isomeric states are larger than those of ground states.
期刊：
International Journal of Heat and Mass Transfer,2016年103:521-537 ISSN：0017-9310
通讯作者：
Zhang, Haiou
作者机构：
[Zhang, Haiou; Zhou, Xiangman] Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.;[Wang, Guilan] Huazhong Univ Sci & Technol, State Key Lab Mat Proc & Die & Mould Technol, Wuhan 430074, Peoples R China.;[Bai, Xingwang] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Zhang, Haiou] H;Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.
关键词：
Arc welding based additive manufacturing;Arc;Metal transport;Numerical simulation
摘要：
In arc welding based additive manufacturing, the surface topographies of deposited layer are more complex than conventional welding, therefore, the distribution of the electromagnetic force in molten pool, arc pressure, plasma shear stress and heat flux on molten pool surface are not the same as the conventional welding. A three-dimensional weak coupling modeling method of the arc and metal transport is developed to simulate the arc, molten pool dynamic and droplet impingement in arc welding based additive manufacturing. In the arc model, the molten pool is simplified to be solid state on the basis of experimentally observed results. The arc is simulated firstly, and then the electromagnetic force, arc pressure, plasma shear stress and heat flux are extracted and transmitted to metal transport model. The volume of fluid (VOF) method is employed to track free surface of molten pool and droplet, and the continuum surface force (CSF) method is applied to transform all the surface forces on free surface as localized body forces. This weak coupling model has better accuracy than empirical model and decreases computational consumption. The molten pool morphology and cross-sectional profile of simulated results accord well with experimental results in both single-bead deposition and overlapping deposition, which indicates that this weak coupling modeling method is capable of simulating the complex heat and mass transfer phenomena in arc welding based additive manufacturing. (C) 2016 Elsevier Ltd. All rights reserved.
期刊：
Journal of Materials Science,2016年51(14):6735-6749 ISSN：0022-2461
通讯作者：
Zhang, Haiou
作者机构：
[Zhang, Haiou; Zhou, Xiangman] Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.;[Zhao, Jingyi; Wang, Guilan; Fu, Youheng] Huazhong Univ Sci & Technol, State Key Lab Mat Proc & Die & Mould Technol, Wuhan 430074, Peoples R China.;[Bai, Xingwang] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Zhang, Haiou] H;Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China.
关键词：
Solid Fraction;Cellular Automaton;Weld Bead;Rolling Reduction;Cellular Automaton Model
摘要：
Hybrid deposition and micro-rolling (HDMR) is a metal additive manufacturing process that integrates arc direct deposition manufacturing and micro-rolling. A two-dimensional cellular automata and finite volume method coupling model is developed for simulating the microstructure evolution of solidification and the dynamic recrystallization during HDMR forming. The influences of different rolling reductions on dynamic recrystallization fraction, average equivalent radius of recrystallized grains, and the area of dynamic recrystallization region are discussed. The results show that solidification microstructure consists of complete columnar dendrite. The rolling reduction plays a dominant role in determining the area of dynamic recrystallization region and the size of recrystallized grains. The average recrystallized grain size at the top position is not affected by rolling reduction, while the influence of rolling reduction on the dynamic recrystallization fraction and average radius of recrystallized grain is found to be stable, but not linear. The same qualitative and quantitative conclusions are drawn from the experimental results as well.
作者机构：
[Guo, Ping; Sun, Xiao-Dong] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Li, Xiao-Hua] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Li, Xiao-Hua] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Peoples R China.
通讯机构：
[Li, Xiao-Hua] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Peoples R China.
摘要：
α decay is a common and important process of natural radioactivity of heavy and superheavy nuclei. The α decay half-lives for even-even nuclei from Z=62 to Z=118 are systematically studied based on the two-potential approach with a quasistationary state approximation. As for the nuclear potential, the isospin effect is considered, which slightly improves the results by 6.8%. To reduce the deviations between experimental half-lives and calculated results due to the nuclear shell structure, the analytic expression of hindrance factors is employed. Our results can reproduce the experimental half-lives as good as using the density-dependent cluster model and the generalized liquid drop model.
作者机构：
[Guo, Ping; Sun, Xiao-Dong] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Li, Xiao-Hua] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Li, Xiao-Hua] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Peoples R China.
通讯机构：
[Li, Xiao-Hua] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Peoples R China.
摘要：
In this work, we systematically investigate the favored α-decay half-lives and α preformation probabilities of both odd- A and doubly-odd nuclei related to ground and isomeric states around the doubly magic cores at Z=82, N=82 and at Z=82, N=126, respectively, within a two-potential approach from the view of the valence nucleon (or hole). The results show that the α preformation probability is linearly related to NpNn or NpNnI, where Np, Nn, and I are the number of valence protons (or holes), the number of valence neutrons (or holes), and the isospin of the parent nucleus, respectively. Fitting the α preformation probabilities data extracted from the differences between experimental data and calculated half-lives without a shell correction, we give two analytic formulas of the α preformation probabilities and the values of corresponding parameters. Using those formulas and the parameters, we calculate the α-decay half-lives for those nuclei. The calculated results can well reproduce the experimental data.
摘要：
We investigate the properties of strange quark matter (SQM) and quark stars (QSs) in the framework of SU(3) Nambu–Jona-Lasinio (NJL) model with two types of vector interactions under strong magnetic fields: (1) the flavor-dependent repulsion among u, d, and s quarks with the coupling constant GV, and (2) the universal repulsion and the vector-isovector interaction with the coupling constants gV and GIV. The effects of the two types of vector interactions on the constituent quark mass, vacuum quark mass, quark chemical potential, and quark fraction in SQM under strong magnetic fields are studied, and the results indicate that these physical quantities for SQM are all sensitive to the two types of vector interactions in NJL model under magnetic fields. Using a density-dependent magnetic field profile which is introduced to describe the magnetic field strength distribution inside the magnetars, we calculate the properties of spherical QSs by using two extreme cases for the orientation of the magnetic field inside the stars, i.e., the radial orientation in which the magnetic fields are along the radial direction in stars, and the transverse orientation in which the magnetic fields are randomly oriented in the plane which is perpendicular to the radial direction. Our results indicate that the maximum mass of QSs may dependent on both the strength distribution and the orientation of the magnetic fields inside QSs by using SU(3) NJL model.
摘要：
Manufacturing the complex surface of personal artificial bone by laser rapid prototyping has always been difficult in artificial bone forming. An approach to this challenge is presented based on the CT slice data of natural bone. The artificial bone was customised by means of building an STL model and using the laser rapid prototyping method. Firstly, the CT slice data of natural bone was obtained by CT scanning. The edge detection and 8-connected boundary tracking algorithm were utilised to obtain the natural bone contour data of each slice. Secondly, in order to meet the process requirements of layer thickness in laser rapid prototyping, profile matching points were established on every two adjacent layers. Linear interpolation was used to gain intermediate contour data according to the profile matching points. Then, the contours of natural bone were fitted by a cubic spline curve. Finally, the STL model of natural bone was generated by minimum diagonal triangulation and the laser rapid prototyping machine was put into service to print the artificial bone.
作者机构：
[Zhang, Zhen-Hua] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.;[Zhang, Zhen-Hua] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Hunan, Peoples R China.;[Wang, Chao; Guo, Xin-Heng] Beijing Normal Univ, Coll Nucl Sci & Technol, Beijing 100875, Peoples R China.
通讯机构：
[Zhang, Zhen-Hua] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.
关键词：
CP violation;Heavy baryon;Bottom quark
摘要：
We propose a new mechanism which can introduce large CP asymmetries in the phase spaces of three-body decays of heavy baryons. In this mechanism, a large CP asymmetry is induced by the interference of two intermediate resonances, which subsequently decay into two different combinations of final particles. We apply this mechanism to the decay channel Lambda(0)(b) -> p pi(0)pi(-), and find that the differential CP asymmetry can reach as large as 50%, while the regional CP asymmetry can reach as large as 16% in the interference region of the phase space. (C) 2015 The Authors. Published by Elsevier B.V.
作者机构：
[Chen, Chunlin; Chen, Yong; Chen, Yue; Qiu, Changjun] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Chen, Chunlin; Wang, Zhongchang; Chen, Yong] Tohoku Univ, Adv Inst Mat Res, Aoba Ku, Sendai, Miyagi 980, Japan.
通讯机构：
[Chen, Chunlin] U;Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
关键词：
Au/CeO2;Hydrothermal synthesis;Scanning transmission electron microscopy
摘要：
Gold nanoparticles supported on oxide substrates are widely utilized as heterogeneous catalysts. Here, we apply a facile surfactant- and template-free hydrothermal method to fabricate Au/CeO2 nanostructures, and show a successful preparation of well-defined CeO2 nano-octahedrons with Au nanoparticles on their surface. The high-angle annular dark field scanning transmission microscopy imaging technique is applied to investigate microstructure of the Au/CeO2 nanostructure. We find that the Au clusters with a diameter of less than 2 nm cannot form the FCC Au lattice, and that twins emerge in the Au nanoparticles with a diameter of larger than 2 nm. Moreover, we identify preferential orientation relationships {111}(Au) parallel to {111}(CeO2) and < 110 >(Au) parallel to < 110 >(CeO2) between the Au nanoparticles and CeO2 nano-octahedrons. (C) 2014 Elsevier B.V. All rights reserved.
期刊：
Journal of the European Ceramic Society,2015年35(5):1385-1391 ISSN：0955-2219
通讯作者：
Qiu, Changjun
作者机构：
[Liu, Wulong; Qiu, Changjun] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Huang, Qing; Zhou, Jie; Zhou, Xiaobing; Liu, Wulong; Ding, Zhihui; Du, Shiyu; Qiu, Changjun] Chinese Acad Sci, Div Funct Mat & Nanodevices, Ningbo Inst Mat Technol & Engn, Ningbo 315201, Zhejiang, Peoples R China.;[Ha, Young-Hwan] Yeungnam Univ, Sch Mat Sci & Engn, Gyongsan, South Korea.
通讯机构：
[Qiu, Changjun] C;Chinese Acad Sci, Div Funct Mat & Nanodevices, Ningbo Inst Mat Technol & Engn, Ningbo 315201, Zhejiang, Peoples R China.
关键词：
MAX phase;Microwave sintering;Synthesis;Ti2AlN
摘要：
Porous Ti<inf>2</inf>AlN ceramic, which was measured to be 3.23g/cm<sup>3</sup> about 74.9% of its theoretical value, was successfully synthesized and simultaneously consolidated from starting raw materials of Ti, Al, and TiN powders with a near-stoichiometric molar ratio of 1:1.03:1 by a microwave sintering method at 1200°C for 30min in an argon atmosphere. When sintered at 1200°C for 1h, the Ti<inf>2</inf>AlN grain showed a preferred growth behavior along the c-axis in the final ceramic, as shown by the results of an X-ray diffraction study. The Lotgering orientation factor on the surface of as-sintered Ti<inf>2</inf>AlN ceramic was as high as f<inf>(00ℓ)</inf>=0.598. A traditional synthesis method in a quartz tube furnace was also applied to synthesize the materials under the same conditions, but this did not result in similar preferred grain growth phenomenon. Factors affecting the orientation were discussed, and an underlying growth mechanism was suggested. Also, a dense Ti<inf>2</inf>AlN sample was obtained by re-sintering the porous Ti<inf>2</inf>AlN sample using a spark plasma sintering method. As a result, the orientation was maintained, and the density was measured to be 4.21g/cm<sup>3</sup>, which reached 97.6% of its theoretical value.
摘要：
To combat thermal-induced problems such as residual stress, deformation, and crack, induction heating is introduced into weld-based additive manufacturing process as a controlled thermal intervention. To date, however, numerical simulation of this induction-assisted weld-based additive manufacturing process is still a tough task; for conducting transient thermoelectromagnetic motion, coupling analysis is computationally prohibitive. In this paper, a simulation strategy is devised to address the problem. The coupling analysis is performed only at a typical time to obtain the representative distribution of induction heat, which is then transferred to the thermal analysis of multilayer deposition as a moving heat source. Utilizing this strategy, the effects of real-time induction preheating and postheating on residual stress state are analyzed in comparative simulations. The results show that both induction preheating and postheating lead to more homogeneous heat input and lower residual stresses compared with the case without induction heating.
作者机构：
[Zhang Zhen-Hua] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Zhang Zhen-Hua; Lu, Gang] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Peoples R China.;[Wei Ke-Wei; Lu, Gang] Henan Univ Technol, Coll Sci, Zhengzhou 450001, Peoples R China.;[Wei Ke-Wei] Anyang Normal Univ, Coll Phys & Elect Engn, Anyang 455002, Peoples R China.
通讯机构：
[Zhang Zhen-Hua] U;Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
关键词：
X(3872);mass degeneracy;B meson
摘要：
The spin is an important property of a particle. Although it is unlikely, there is still a possibility that two particles with different spins share similar masses. In this paper, we propose a method to probe this kind of mass degeneracy of particles with different spins. We use the cascade decay B+→X(3872)K+, X(3872)→D+D- to illustrate our method. It can be seen that the possible mass degeneracy of X(3872) can lead to interesting behavior in the corresponding cascade decay.
