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Vector meson effects on multi-Skyrmion states from the rational map ansatz

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Science China(Physics,Mechanics & Astronomy) 2023年第11期66卷 126-135页

作者： Jun-Shuai Wang Yong-liang ma College of Physics Jilin UniversityChangchun130012China School of Fundamental Physics and mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences(UCAS)Hangzhou310024China TaiJi Laboratory for Gravitational Wave Universe(Beijing/Hangzhou) UCASBeijing100049China

The roles of the lightest vector mesons ρ and ω in the multi-Skyrmion states are studied using the hidden local symmetry approach up to the next-to-leading order,including the homogeneous Wess-Zumino *** low-energy constants in the effective field theory are determined using the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills *** only two inputs,m_(ρ) and f_(π),it is possible to determine all low-energy constants without *** vector meson effects can be investigated by sequentially integrating vector mesons,and their geometry can be elucidated by comparing the results using the low-energy constants estimated from the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills *** found that theρmeson reduces the masses of the multi-Skyrmion states and increases the overlaps of their constituents,whereas theωmeson repulses the constituents of the multi-Skyrmion states and increases their ***,these vector mesons are crucial in the Skyrme model approach to *** also found that the warping factor,an essential element in the holographic model of QCD,affects the properties of the multi-Skyrmion states and cannot be ignored.

关键词： vector meson multi-Skyrmion state rational map hidden local symmetry

Numerical simulation of flow past a square cylinder with a circular bar upstream and a splitter plate downstream

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Journal of Hydrodynamics 2019年第5期31卷 949-964页

作者： yuan ma MMRashidi Zhi-gang Yang Shanghai Automotive Wind Tunnel Center Tongji UniversityShanghai 201804China Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal management Systems Shanghai 201804China Department o f Civil Engineering School of EngineeringUniversity of BirminghamBirminghamUK

A numerical investigation of flow past a square cylinder with a circular bar upstream and a splitter plate downstream is carried out in this paper by lattice Boltzmann method(LBM).The combination of the three obstacles and LBM is the main novelty of the present *** flow patterns are analyzed by a uniform flow of Reynolds number 100 based on the side length of the square cylinder,*** simulations are performed in the range of 1≤Ds/D≤5,0≤G/D≤7 and 1≤L/D≤6,where Ds,G and L are the center-to center distance,surface-to-surface distance and the splitter plate length,*** flow patterns are observed in the present *** maximum percentage reduction in mean drag coefficient is 68.76%at(ds,g,l)=(2.5,0,3)which is in pattern *** vortex shedding from the square cylinder and the circular bar can be completely suppressed in pattern *** small distance between the square cylinder and the splitter plate plays a more vital role in suppression of vortex shedding as compared with large distance and length.

关键词： Square cylinder lattice Boltzmann method(LBM) reduction of drag forces vortex shedding control circular bar splitter plate

Continuum damage mechanics for sintered powder metals

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Science China(Physics,Mechanics & Astronomy) 2015年第1期58卷 95-106页

作者： yuan Huang ma SongYun ZHANG Long Beijing Institute of Technology School of Mechanical Engineering University of Wuppertal Department of Mechanical Engineering

Sintered metals are characterized by the high porosity(8%)and voids/micro-cracks in *** behavior of the materials is coupled with micro-crack propagation and coalescence of open *** the present work the damage evolution of the sintered iron under multi-axial monotonic loading conditions was investigated experimentally and *** tests indicated that damage of the sintered iron initiated already at a stress level much lower than the macroscopic yield *** damage process can be divided into the stress-dominated elastic damage and the plastic damage described by the plastic *** on the uniaxial tensile tests an elastic-plastic continuum damage model was developed which predicts both elastic damage and plastic damage in the sintered iron under general multi-axial monotonic loading *** predictions agree with experiments with different multi-axial loading paths.A phenomenological continuum damage model for the sintered metal is developed based on the experimental observations to predict the inelastic behavior and damage process to failure under multi-axial loading *** proposed damage model is experimentally verified under different loading conditions.

关键词： sintered metal porous material damage evolution multi-axial damage continuum damage model

Investigating the Effects of Para-methoxy Substitution in Sterically Enhanced Unsymmetrical Bis(arylimino)pyridine-cobalt Ethylene Polymerization Catalysts

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Chinese Journal of Polymer Science 2022年第3期40卷 266-279,I0007页

作者： Yi Yan Shi-Fang yuan Ming Liu Gregory A.Solan Yan-Ping ma Tong-Ling liang Wen-Hua Sun Institute of Applied Chemistry Shanxi UniversityTaiyuan 030006China Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of SciencesBeijing 100190China Department of Chemistry University of LeicesterUniversity RoadLeicester LE17RHUK State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

A group of five bis(arylimino)pyridine-cobalt(Ⅱ)chloride complexes,[2-{(2,6-(Ph_(2)CH)_(2)-4-MeOC_(6)H_(2))N=CMe}-6-(ArN=CMe)C_5 H_(3)N]CoCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3)Co1,2,6-Et_(2)C_(6)H_(3)Co2,2,6-iPr_(2)C_(6)H_(3)Co3,2,4,6-Me_(3)C_(6)H_(2)Co4,2,6-Et_(2)-4-MeC_(6)H_(2)Co5),each containing one N-4-methoxy-2,6-dibenzhydrylphenyl group and one smaller sterically/electronically variable N-aryl group,have been synthesized in good yield(>71%)from the corresponding neutral terdentate nitrogen-donor precursor,*** complexes have been characterized by^(1)H-NMR and FTIR spectroscopy with the former highlighting the paramagnetic nature of these cobaltous species and the unsymmetrical nature of the chelating *** molecular structures of Co3 and Co4 emphasize the steric differences of the two inequivalent N-aryl groups and the distorted square pyramidal geometry about the metal *** the presence of maO or MmaO,Co1-Co5 collectively displayed high activities for ethylene polymerization producing high molecular weight polyethylenes that,in general,exhibited narrow dispersities(M_w/M_n values:2.12-4.07).Notably,the least sterically hindered Co1 when activated with maO was the most productive(6.92×10^(6)g_(PE)·mol^(-1)_((Co))·h^(-1))at an operating temperature of60℃.Conversely,the most sterically hindered Co3/MmaO produced the highest molecular weight polyethylene(M_w=6.29×10^(5)g·mol^(-1)).All the polymers displayed high linearity as demonstrated by their melting temperatures(>130℃)and their~1 H-and^(13)C-NMR *** comparison of Co1 with its para-methyl,-chloro and-nitro counterparts,the presence of the para-methoxy substituent showed the most noticeable effect of enhancing the thermal stability of the catalyst.

关键词： Cobalt(II)precatalyst Ethylene polymerization High molecular weight polyethylene Electronic effects Thermal stability

Unlicensed Spectrum Sharing Game Between LEO Satellites and Terrestrial Cognitive Radio Networks

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Chinese Journal of Aeronautics 2012年第4期25卷 605-614页

作者： XIE Zhuochen ma LU liang Xuwen Shanghai Engineering Center for Micro-satellites Shanghai 200050China Shanghai Institute of Microsystem and Information Technology Chinese Academy of SciencesShanghai 200050China Graduate University of Chinese Academy of Sciences Beijing 100049China

By cognitive radio,the low Earth orbit（LEO） satellites may prefer to operate in the unlicensed spectrum which is open to all the users,and compete for the limited resources with terrestrial cognitive radio networks（CRNs）.The competition can be regarded as a game and analyzed with game *** particular unlicensed spectrum sharing problem is modeled here,and the special properties of ＂spatially-distinguished-interference＂ and the short period of the interactions between satellites and terrestrial CRNs are ***,the problem is formulated as a ＂partially-blind＂ finitely repeated prisoner＇s dilemma by game ***,we begin with two promising spectrum sharing schemes,which can be used to enforce the frequency reuse among the remotely located terrestrial CRN players as well as to overcome the observation *** analysis and comparison,it is proposed that the novel refreshing-contrite-tit-for-tat（R-CTFT） is the optimal spectrum sharing *** results verify that it can be used to utilize the spectrum most efficiently.

关键词： satellite communication systems cognitive radio unlicensed spectrum sharing spatially-distinguished-interference finitely repeated prisoner's dilemma partially-blind refreshing-contrite-tit-for-tat

Adjoint-Based Geometrically Constrained Aerodynamic Optimization of a Transonic Compressor Stage

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Journal of Thermal Science 2019年第5期28卷 850-861页

作者： SU Xinrong ma Can yuan Xin Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing 100084 China Science and Technology on Thermal Energy and Power Laboratory Wuhan 430205 China

Efficient method to handle the geometric constraints in the optimization of turbomachinery blade profile is required. Without constraints on the blade thickness, optimal designs typically yield thinner blade to reduce the friction loss, however, at the risk of degraded strength and stiffness. This issue is seldom discussed and existing literature always treat the blade thickness constraint in an indirect manner. In this work, two different geometric constraints on the blade thickness are proposed and applied in the adjoint optimization: one is on the maximum blade thickness and the other is on the blade area. Methods to compute sensitivities of both constraints are proposed and they are integrated into an optimization system based on a finite volume code and a solver for the discrete adjoint equation. Adjoint optimization is conducted to minimize the entropy production in a transonic compressor stage. Results for the adjoint optimization without geometry constraint and two comparative cases are detailed. It is indicated that three cases yield similar performance improvement;however, if geometry constraints are properly handled, the optimal designs have almost the same maximum thickness as the original design, compared to a thinner blade profile with 14% reduction of maximum thickness in the case without geometry constraint. The cases considering geometry constraints also consume slightly reduced Central Processing Unit(CPU) cost. Result of this work verifies the effectiveness of the proposed method to treat geometric constraints in adjoint optimization.

关键词： aerodynamic optimization compressor stage discrete adjoint method geometric constraint

making More Sense of Human Intention Detection via Reconstruction Models

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China Communications 2020年第7期17卷 193-206页

作者： Wei liang Dalin Zhang Xigang yuan School of Computer Science and Engineering Changshu Institute of TechnologyChangshu 215500China School of Computer Science and Engineering University of New South Wales2052 NSWAustralia Business School Jiangsu Normal UniversityXuzhou 221116China

Movement intention recognition paves the path to developing Brain-Computer Interface(BCI)*** research mostly focuses on questions like"which hand is intended to move".While answering questions like"whether a hand is intended to move"is more desirable for widely realworld applications,because we cannot continuously perform intention tasks during usage,and the gap periods may cause unintended operation resulting in system ***,this kind of intention detection task is more difficult,since for a"whether"problem,it is hard to know what the"not"situation is and consequently to acquire training samples for the"not"***,the occurrence of genuine intentions is comparatively scarce and unexpected,making the intention detection task hard and *** tackle this problem,we propose a Reconstruction-based Intention Detection(RID)framework,which utilises a reconstruction model to represent a high-level abstraction of EEG signals and leverages the reconstruction errors to determine"whether"there is a movement *** framework is not only theoretically flexible and robust to any sophisticated real-world scenarios but also hand-crafted feature and domain knowledge *** experiments on detecting movement intention tasks with different reconstruction models demonstrate the promising performance of the proposed reconstruction intention detection framework.

关键词： intention consuming mostly

Coal seam drainage enhancement using borehole presplitting basting technology——A case study in Huainan

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International Journal of Mining Science and Technology 2017年第5期27卷 771-775页

作者： Chen Xianzhan Xue Sheng yuan liang School of Mining and Safety Engineering Anhui University of Science and TechnologyHuainan 232001China Anhui Coal Mine Safety Supervision Bureau Hefei 230088China CSIRO Energy PO Box 883KenmoreQLD 4069Australia

Xinji No. 2 underground coal mine extracts the coal seams #4 and #5. These two seams are highly gassy and gas drainage is required to control mine gas emission and reduce outburst risk. Because the seam permeability coefficient is very low and around 0.1 m^2/(MPa^2·d), a number of technologies have been trialled to enhance the seam permeability prior to gas drainage. Of these technologies trialled, the deep borehole presplitting blasting technology has been proven to be quite effective in increasing permeability. In Xinji No. 2 mine it doubled or sometimes tripled gas drainage volume. This paper describes the technology, its application in the enhancement of seam permeability in Xinji No. 2 coal mine, and its effect on gas drainage performance.

关键词： Coal mining Gas drainage Permeability enhancement Deep hole blasting

Comprehensive drought monitoring in Yunnan Province, China using multisource remote sensing data

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Journal of Mountain Science 2021年第6期18卷 1537-1549页

作者： WANG Jin-liang YU yuan-he Faculty of Geography Yunnan Normal UniversityKunming 650500China Key Laboratory of Resources and Environmental Remote Sensing for Universities in Yunnan Kunming 650500China Center for Geospatial Information Engineering and Technology of Yunnan Province Kunming 650500China

Development of drought monitoring techniques is important for understanding and mitigating droughts and for rational agricultural management. This study used data from multiple sources, including MOD13 A3, TRMM 3 B43, and SRTMDEM, for Yunnan Province, China from 2009 to 2018 to calculate the tropical rainfall condition index(TRCI), vegetation condition index(VCI), temperature condition index(TCI), and elevation factors. Principal component analysis(PCA) and analytic hierarchy process(AHP) were used to construct comprehensive drought monitoring models for Yunnan Province. The reliability of the models was verified, following which the drought situation in Yunnan Province for the past ten years was analysed. The results showed that:(1) The comprehensive drought index(CDI) had a high correlation with the standardized precipitation index, standardized precipitation evapotranspiration index, temperature vegetation dryness index, and CLDAS(China Meteorological Administration land data assimilation system), indicating that the CDI was a strong indicator of drought through meteorological, remote sensing and soil moisture monitoring.(2) The droughts from 2009 to 2018 showed generally consistent spatiotemporal changes. Droughts occurred in most parts of the province, with an average drought frequency of 29% and four droughtprone centres.(3) Monthly drought coverage during 2009 to 2014 exceeded that over 2015 to 2018. January had the largest average drought coverage over the study period(61.92%). Droughts at most stations during the remaining months except for October exhibited a weakening trend(slope > 0). The CDI provides a novel approach for drought monitoring in areas with complex terrain such as Yunnan Province.

关键词： Multisource data Comprehensive drought index(CDI) Standardized precipitation index(SPI) Standardized precipitation evapotranspiration index(SPEI) Temperature vegetation dryness index(TVDI) Yunnan Province China