检索结果-南通市图书馆

Triaxiality and shape coexistence in the A ～ 30 “island of inversion”nuclei

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2015年第11期58卷 99-106页

作者： dong guoxiang WANG XiaoBao YU ShaoYing School of Science Huzhou University

Understanding the properties of nuclei inside "island of inversion" is still an interesting issue. Based on a simple Nilsson model with a new set of isospin-dependent parameters, and with non-axial deformations considered, we have performed three-dimensional potential-energy-surface calculations for Ne, Na, Mg and Al isotopes that are claimed to be in or nearby the A～30 island of inversion". It is found that shape coexistence and triaxial deformation(or softness) exist in these nuclei. Large deformations are obtained by the improved Nilsson parameters, which explains the observed large electric quadrupole transition probabilities. The large deformations happening in30 Ne,31Na,32 Mg and33Al indicate the quenching of the spherical N = 20 neutron shell gap. The calculations of nuclear binding and two-neutron separation energies have been also improved with the isospin-dependent parameters and the inclusion of the non-axial deformation degree of freedom.

关键词： island of inversion shell evolution triaxial deformation shape coexistence

An investigation of ab initio shell-model interactions derived by no-core shell model

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2016年第9期59卷 52-58页

作者： XiaoBao Wang guoxiang dong QingFeng Li CaiWan Shen ShaoYing Yu School of Science Huzhou University

The microscopic shell-model effective interactions are mainly based on the many-body perturbation theory （MBPT）, the first work of which can be traced to Brown and Kuo＇s first attempt in 1966, derived from the Hamada-Johnstou nucleon-nucleon potential. However, the convergence of the MBPT is still unclear. On the other hand, ab initio theories, such as Green＇s function Monte Carlo （GFMC）, no-core shell model （NCSM）, and coupled-cluster theory with single and double excitations （CCSD）, have made many progress in recent years. However, due to the increasing demanding of computing resources, these ab initio applications are usually limited to nuclei with mass up to A = 16. Recently, people have realized the ab initio construction of valence-space effective interactions, which is obtained through a second-time renormalization, or to be more exactly, projecting the full-many- body Hamiltonian into core, one-body, and two-body cluster parts. In this paper, we present the investigation of such ab initio shell-model interactions, by the recent derived sd-shell effective interactions based on effective J-matrix Inverse Scattering Potential （JISP） and chiral effective-field theory （EFT） through NCSM. In this work, we have seen the similarity between the ab initio shell- model interactions and the interactions obtained by MBPT or by empirical fitting. Without the inclusion of three-body （3-bd） force, the ab initio shell-model interactions still share similar defects with the microscopic interactions by MBPT, i.e., T = 1 channel is more attractive while T = 0 channel is more repulsive than empirical interactions. The progress to include more many-body correlations and 3-bd force is still badly needed, to see whether such efforts of ab initio shell-model interactions can reach similar precision as the interactions fitted to experimental data.

关键词： shell model effective interactions ab initio methods

Collective properties of neon isotopes investigated by projected shell model

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2014年第29期59卷 3847-3852页

作者： guoxiang dong Xiaobao Wang Furong Xu Shaoying Yu State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking University Department of Physics University of Jyvskyl40014 JyvskylFinland School of Science Huzhou Teachers College

Collective phenomenon in neon isotopes is an interesting ***,even the ground-state deformations cannot be well described by ***,QJ Zhi and ZZ Ren[Phys Lett B 638:166(2006)]have suggested an improved Nilsson potential,which can give a suitable description of ground-state properties in magnesium *** order to test the description of neon isotopes located around the‘‘island of inversion’’,we have used this potential to provide the deformed basis for the projectedshell-model *** low-lying spectra and transition properties of neon isotopes can be reproduced *** gyromagnetic factors of neon isotopes have also been *** structures of excited states along the yrast line are studied in the language of band diagrams.

关键词：氖同位素投影壳模型基态性质集体霓虹灯物理学尼尔森激发态

Wideband radar cross-section reduction using plasma-based checkerboard metasurface

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2022年第8期24卷 98-104页

作者： Zhiming ZHAO Xiaoping LI guoxiang dong Yanming LIU School of Aerospace Science and Technology Xidian UniversityXi'an 710126People's Republic of China

For stealth technology,in order to overcome the limitations of thin-layer plasma for electromagnetic waves attenuation and further broaden the radar cross-section(RCS)reduction(RCSR)band of the metasurface,the plasma-based checkerboard metasurface composed of plasma and checkerboard metasurface is investigated to achieve better *** designed a checkerboard metasurface which can achieve abnormal reflection to reduce RCS and whose-10d B RCSR bandwidth is from 8.1 to 14.5 GHz,the RCSR principle of it lies in the backscattering cancellation,which depends on the phase difference of artificial magnetic conductor(AMC)*** designed plasma-based checkerboard metasurface is a thin composite structure,including a checkerboard metasurface,a plasma layer,and an air gap which is between *** wave simulations confirm that the plasma-based checkerboard metasurface’s–10 dB RCS reduction bandwidth and RCS reduction amplitude,are both increased under different polarized waves compared with the only single plasma or the only *** also introduced the reason and mechanism of the interaction between plasma and the checkerboard metasurface to improve the RCSR effect in *** plasma-based checkerboard metasurface does not need the plasma to be too thick for plasma stealth,its application in practical scenarios is easier to implement.

关键词： abnormal reflection plasma-based checkerboard metasurface radar cross section reduction(RCSR) stealth technology

Energy spreading,equipartition,and chaos in lattices with non-central forces

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第2期31卷 119-128页

作者： Yong-Jing Chen Yang Su guoxiang dong Li-Le Liu Zhigang GeXiaobao Wang China Nuclear Data Center China Institute of Atomic EnergyBeijing 102413China School of Science Huzhou UniversityHuzhou 313000China

We numerically study a one-dimensional,nonlinear lattice model which in the linear limit is relevant to the study of bending(flexural)*** contrast with the classic one-dimensional mass-spring system,the linear dispersion relation of the considered model has different characteristics in the low frequency *** introducing disorder in the masses of the lattice particles,we investigate how different nonlinearities in the potential(cubic,quadratic,and their combination)lead to energy delocalization,equipartition,and chaotic *** excite the lattice using single site initial momentum excitations corresponding to a strongly localized linear mode and increase the initial energy of *** a certain energy threshold,when the cubic nonlinearity is present,the system is found to reach energy equipartition and total *** the other hand,when only the quartic nonlinearity is activated,the system remains localized and away from equipartition at least for the energies and evolution times considered ***,for large enough energies for all types of nonlinearities we observe *** chaotic behavior is combined with energy delocalization when cubic nonlinearities are present,while the appearance of only quadratic nonlinearity leads to energy *** results reveal a rich dynamical behavior and show differences with the relevant Fermi–Pasta–Ulam–Tsingou *** findings pave the way for the study of models relevant to bending(flexural)waves in the presence of nonlinearity and disorder,anticipating different energy transport behaviors.

关键词： Anderson localization energy spreading energy equipartition chaos

Characteristics of the electromagnetic wave propagation in magnetized plasma sheath and practical method for blackout mitigation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第5期33卷 489-499页

作者：吴翔张珈珲董果香石磊 School of Aerospace Science and Technology Xidian UniversityXi'an 710071China

“Magnetic window”is considered as an effective method to solve the communication blackout *** software package based on the finite element method is utilized to simulate the propagation of right-handed circularly polarized wave in the magnetized plasma *** assume a double Gaussian model of electron density and an exponential attenuation model of magnetic *** propagation characteristics of right-handed circularly polarized wave are analyzed by the observation of the reflected,transmitted and loss *** numerical results show that the propagation of right-handed circularly polarized wave in the magnetized plasma sheath varies for different incident angles,collision frequencies,non-uniform magnetic fields and non-uniform plasma *** notice that reducing the wave frequency can meet the propagation conditions of whistle mode in the weak magnetized plasma *** the transmittance of whistle mode is less affected by the variation of the electron density and the collision *** can be used as a communication window.

关键词： magnetized plasma sheath communication blackout finite element incident angle whistler wave

Energy density functional analysis of the fission properties of^(240)Pu:The effect of pairing correlations

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2022年第2期46卷 105-111页

作者： Yong-Jing Chen Yang Su guoxiang dong Li-Le Liu Zhigang Ge Xiaobao Wang China Nuclear Data Center China Institute of Atomic EnergyBeijing 102413China School of Science Huzhou UniversityHuzhou 313000China

We have calculated the potential energy surfaces for ^(240)Pu up to the scission point using the density functional theory with different pairing strengths to investigate the effect of pairing correlations on its fission *** enhancement in the pairing correlations lowers the barrier heights,isomeric state,and ridge between the symmetric and asymmetric fission valleys ***,it weakens the microscopic shell structure around the Fermi surface,shrinks the scission frontiers,especially for the symmetric and very asymmetric fission regions,and lifts the total kinetic energies(TKEs)for the symmetric fission *** is also emphasized that the microscopic calculation qualitatively reproduces the trend of the distribution of the measured TKEs,especially for the positions of the peaks at A_(frag)≈132 and A_(frag)≈108.

关键词： density functional theory potential energy surface nuclear fission

Development of Energy-Saving Devices for a 20,000DWT River–Sea Bulk Carrier

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2018年第1期17卷 131-139页

作者： Kunpeng Chen Yuling Gao Zhenping Huang guoxiang dong State Key Laboratory of Navigation and Safety Technology Shanghai Ship&Shipping Research InstituteShanghai 200135China

A reduction of fuel consumption and an increase in efficiency are currently required for river–sea bulk ***-swirl and ducted stators are widely used devices in the industry and efficiency gains can be obtained for single-screw and twin-screw *** on the hydrodynamic characteristics of the 20,000DWT river–sea bulk carrier,in this study,we proposed,designed,and tested a series of pre-swirl energy-saving devices(ESDs).The experimental results demonstrate that the proposed ESDs improved the propulsive efficiency and reduced the delivered *** results confirm the success of our ESD for the 20,000DWT river–sea bulk *** validated the role of Reynolds-averaged Navier–Stokes(RANS)computational fluid dynamics(CFD)in the twin-skeg river–sea vessel ESD design and found the circumferential arrangement and number of stators to be important factors in the design process.

关键词： River–sea bulk carrier Energy-saving devices Pre-swirl stators Computational fluid dynamics RANS

Comparison of Different Added Power in Waves Prediction Methods

在线全文

学校读者我要写书评

暂无评论

Journal of Shipping and Ocean Engineering 2018年第1期8卷 21-29页

作者： CHEN Weimin LI Jianpeng dong guoxiang XING Lei State Key Laboratory of Navigation and Safety Technology Shanghai Ship and Shipping Research Institute Shanghai 200135 China

In order to predict the speed loss in the actual sea states more precisely, delivered power shall be measured more accurately as an input. Therefore, based on a 50,000 DWT tanker, various results obtained from different prediction methods were compared by a series of model tests performed in calm water and in waves. It is shown that speed loss deprived from RTIM （resistance and thrust identity method） method in regular waves test could satisfy the engineering requirements most.

关键词： Added power model test speed loss sea keeping prediction self propulsion test in waves.