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New explicit algebraic stress and flux model for active scalar and simulation of shear stratified cylinder wake flow

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Science China(Technological Sciences) 2009年第9期52卷 2536-2546页

作者： hua ZuLin GU Li XING LingHang dai WenHong Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education College of Environmental Science&EngineeringHohai UniversityNanjing 210098China Yangtze River Scientific Research Institute Wuhan 430010China Centre for Water and Environment Queen’s UniversityKingstonOntarioK7L3N6Canada

On the numerical simulation of active scalar,a new explicit algebraic expression on active scalar flux was derived based on Wikstrm,Wallin and Johansson model (aWWJ model). Reynolds stress algebraic expressions were added by a term to account for the buoyancy effect. The new explicit Reynolds stress and active scalar flux model was then established. Governing equations of this model were solved by finite volume method with unstructured grids. The thermal shear stratified cylinder wake flow was computed by this new model. The computational results are in good agreement with laboratorial measurements. This work is the development on modeling of explicit algebraic Reynolds stress and scalar flux,and is also a further modification of the aWWJ model for complex situations such as a shear stratified flow.

关键词： active scalar explicit algebraic model scalar flux Reynolds stress thermal shear stratified cylinder wake flow numerical simulation

Synthesis and Crystal Structure of a Novel Manganese Coordination Polymer Constructed by 3,5-Dimethylbenzoic Acid with 4,4'-Bipyridine

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Chinese Journal of Structural Chemistry 2006年第10期25卷 1213-1216页

作者： ZHANG Chun-hua CHEN Man-Sheng KUANG dai-Zhi Department of Chemistry and Materials Science Hengyang Normal University Hengyang 421008 China

A novel manganese coordination polymer [Mn（L）2（bipy）]n （HL = 3,5-dimethylbenzoic acid, 4,4＇-bipy = 4,4＇-bipyridine） has been synthesized by a hydrothermal method. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 2.0996（8）, b = 1,1835（5）, c = 0.9958（4） nm, β = 110.161（5）°, V = 2,3229（16） nm^3, Z = 4, C28H26MnN2O4, Mr = 509.45, Dc= 1.457 g/cm^3,μ = 0.607 mm^-1, F（000） = 1060, Rim = 0.0566, R = 0.0334 and wR = 0.1078. In the crystal the manganese atom is six-coordinated by two nitrogen atoms from 4,4＇-bipy and four oxygen atoms from 3,5-dimethylbenzolate molecules, completing an octahedral geometry. The 4,4＇-bipy molecules bridge the infinite chain [Mn（L）2（bipy）]n to form a two-dimensional layer.

关键词： manganese coordination polymer hydrothermal synthesis crystal structure

Diagnosis and Treatment of Uveal Effusion Syndrome: a Case Series and Literature Review

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Chinese Medical Sciences Journal 2011年第4期26卷 231-236页

作者： Chan Wu Fang-tian Dong hua Zhang You-xin Chen Rong-ping dai Ke Tan Department of Ophthalmology Peking Union Medical College HospitalChinese Academy of Medical Sciences ＆ Peking Union Medical College Beijing 100730 China

Objective To explore the diagnosis, classification, and management of uveal effusion syndrome (UES). Methods The clinical data of 10 patients diagnosed with UES in our hospital between 1990-2010 were extracted from hospital records and analyzed, including ophthalmologic examination, ophthalmologic ultrasonography, ultrasound biomicroscopy (UBM), fundus fluorescence angiography (FFA), indocyanine green (ICG) angiography, surgical procedures, and outcomes. Results The fundus examination of all impacted eyes showed bullous retinal detachment shifting with head position, confirmed by ultrasonography revealing retinal and choroidal detachment. UBM showed annular peripheral ciliochoroidal detachment in all cases. FFA was performed in 5 patients and revealed leopard spots without leakage from choroid into subretinal space. ICG angiograpy was performed in 3 patients and demonstrated diffused granular marked hyperfluorescence in the choroidal fluorescence in the very early phase, which increased with time and persisted until the late phase. Four eyes of 2 patients underwent full-thickness sclerectomies and 1 eye of 1 patient underwent subscleral sclerectomy, all of whom achieved reattachment of the retina without recurrence during 1-year follow-up. Conclusions Comprehensive preoperative evaluation, including ophthalmologic ultrasonography, computed tomography, and magnetic resonance imaging, is crucial for accurate classification of UES and selection of proper management strategy. Surgical treatment can achieve optimal clinical outcomes for type 1 and type 2 UES.

关键词： uveal effusion syndrome idiopathic classification sclerectomy

Nonlinear frequency analysis of buckled nanobeams in the presence of longitudinal magnetic field

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Acta Mechanica Solida Sinica 2017年第5期30卷 465-473页

作者： Xi-ping Sun Yuan-Zhuo Hong Hu-Liang dai Lin Wang Tianjin Research Institute Water Transport Engineering M.O.TTest Detection Center of Water Transport EngineeringTianjin 300456China Department of Mechanics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment Wuhan 430074China

The nonlinear free vibration around the postbuckling configuration of nonlocal nanobeams with pinned-pinned boundary conditions are analytically investigated, considering the ge- ometric nonlinearity arising from the mid-plane stretching and particularly the effect of a longitudinal magnetic field. When the applied axial force is small, the nanobeam is stable and its free vibration is around the straight equilibrium position. As the axial force becomes large and is beyond a certain critical value （critical axial force）, however, either positive or negative non-trivial equilibrium configuration occurs and the free vibration is around the buckled configuration. The governing equation for the nanobeam before buckling exhibits a cubic nonlinearity while for a buckled nanobeam it contains both cubic and quadratic non- linearities. Based on the nonlinear governing equations, approximate analytical solutions for the postbuckling configuration in terms of the applied axial force are evaluated, show- ing that the magnetic field parameter has a great effect on the critical axial force, buckled displacement and linear frequencies of the nanobeam system. More interestingly, the non- linear frequency is found to be generally higher than the linear frequency in the case of prebuckling regime while it could be lower than the linear one in the case of postbuck- ling regime. The nonlinear frequency can be significantly influenced by the magnetic field, the nonlinear coefficient associated with the mid-plane stretching, and the initial vibration amplitude.

关键词： Nonlocal nanobeamPostbucklingNonlinear frequencyMagnetic fieldVibration

Mechanics of advanced fiber reinforced lattice composites

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Acta Mechanica Sinica 2010年第6期26卷 825-835页

作者： hua-Lin Fan Tao Zeng dai-Ning Fang Wei Yang College of Mechanics and Materials Hohai University Nanjing 210098China Key Laboratory for Advanced Building Materials of Sichuan Province Southwest University of Science and Technology Mianyang 621010China College of Civil Engineering and Architecture Harbin University of Science and TechnologyHarbin 150080China College of Engineering Peking University Beijing 100871China University Office Zhejiang University Hangzhou 310058China

Fiber reinforced lattice composites are lightweight attractive due to their high specific strength and specific *** the past 10 years,researchers developed three-dimensional（3D） lattice trusses and two-dimensional （2D） lattice grids by various methods including interlacing, weaving,interlocking,filament winding and molding hot- *** lattice composites have been applied in the fields of radar cross-section reduction,explosive absorption and heat-resistance. In this paper,topologies of the lattice composites, their manufacturing routes,as well as their mechanical and multifunctional applications,were surveyed.

关键词： Lattice composites Mechanical behaviors Fabrication Multifunction

Experimental Investigation on Ejector Performance Using R134a as Refrigerant

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Journal of Thermal Science 2019年第4期28卷 727-735页

作者： dai Zhengshu YU Bo LIU Pengpeng CHEN Guangming ZHANG hua School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China State Key Laboratory of Air-conditioning Equipment and System Energy Conservation Zhuhai 519070China Institute of Refrigeration and Cryogenics Zhejiang UniversityHangzhou 310027China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai 200093China

Ejector refrigeration has the advantage of low capital cost,simple design,reliable operation,long lifespan and almost no *** only weakness is the low efficiency and its intolerance to deviations from design operation condition.R134 a used in ejector refrigeration system gives better performance in comparison with many other environmental friendly refrigerants as the generation temperature is from 75℃to 80℃.The present work experimentally investigated the on-design and off-design performance of the ejector with fixed geometry using R134 a as refrigerant,and cycle performance of the ejector refrigeration *** experimental prototype was constructed and the effects of primary flow inlet pressure,secondary flow inlet pressure and ejector back pressure on ejector performance and cycle performance were investigated *** operation conditions are:primary flow inlet pressure from 2.2 MPa to 3.25 MPa,secondary flow inlet pressure from 0.36 MPa to 0.51 MPa,ejector back pressure from 0.45 MPa to 0.67 *** were drawn from the experimental results,and the experimental data can be used for validation of theoretical model for both critical and subcritical mode.

关键词： ejector performance refrigeration R134a experiment

On the emergence of gravitational dynamics from tensor networks

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Communications in Theoretical Physics 2023年第8期75卷 134-138页

作者： hua-Yu dai Jia-Rui Sun Yuan Sun School of Physics and Astronomy Sun Yat-Sen UniversityGuangzhou 510275China

Tensor networks are used to describe the ground state wavefunction of the quantum many-body ***,it has been shown that a tensor network can generate the anti-de Sitter(AdS)geometry by using the entanglement renormalization approach,which provides a new way to realize bulk reconstruction in the AdS/conformal field theory ***,whether the dynamical connections can be found between the tensor network and gravity is an important unsolved *** this paper,we give a novel proposal to integrate ideas from tensor networks,entanglement entropy,canonical quantization of quantum gravity and the holographic principle and argue that the gravitational dynamics can be generated from a tensor network if the wave function of the latter satisfies the Wheeler–DeWitt equation.

关键词： AdS/CFT correspondence tensor network emergent gravity

Early identification of stroke through deep learning with multi-modal human speech and movement data

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Neural Regeneration Research 2025年第1期20卷 234-241页

作者： Zijun Ou Haitao Wang Bin Zhang Haobang Liang Bei Hu Longlong Ren Yanjuan Liu Yuhu Zhang Chengbo dai Hejun Wu Weifeng Li Xin Li School of Computer Science and Engineering Sun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Department of Neurology Guangdong Neuroscience InstituteGuangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhouGuangdong ProvinceChina Department of Emergency Medicine Guangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhouGuangdong ProvinceChina

Early identification and treatment of stroke can greatly improve patient outcomes and quality of *** clinical tests such as the Cincinnati Pre-hospital Stroke Scale(CPSS)and the Face Arm Speech Test(FAST)are commonly used for stroke screening,accurate administration is dependent on specialized *** this study,we proposed a novel multimodal deep learning approach,based on the FAST,for assessing suspected stroke patients exhibiting symptoms such as limb weakness,facial paresis,and speech disorders in acute *** collected a dataset comprising videos and audio recordings of emergency room patients performing designated limb movements,facial expressions,and speech tests based on the *** compared the constructed deep learning model,which was designed to process multi-modal datasets,with six prior models that achieved good action classification performance,including the I3D,SlowFast,X3D,TPN,TimeSformer,and *** found that the findings of our deep learning model had a higher clinical value compared with the other ***,the multi-modal model outperformed its single-module variants,highlighting the benefit of utilizing multiple types of patient data,such as action videos and speech *** results indicate that a multi-modal deep learning model combined with the FAST could greatly improve the accuracy and sensitivity of early stroke identification of stroke,thus providing a practical and powerful tool for assessing stroke patients in an emergency clinical setting.

关键词： artificial intelligence deep learning diagnosis early detection FAST screening stroke

Ultrathin surface coating of Cu enabling long-life Zn metal anodes

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Rare Metals 2024年第5期43卷 2125-2135页

作者： Sang-Sang Liu Ya-Ru Liang Wen-Long Chen Ze-hua Wang Yi-Long dai Fu-Gang Qi Zeng-Sheng Ma Xiao-ping Ouyang School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105China Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education Xiangtan UniversityXiangtan 411105China

Aqueous zinc-ion batteries(AZIBs)are regarded as promising energy storage devices due to their low cost,high capacity,and ecological ***,the severe dendritic growth and side reactions hinder their practical applicability ***,an ultrathin Cu coating layer(~200 nm)is decorated on zinc foils via filtered cathodic vacuum arc deposition technology,aiming to achieve high-performance *** Cu layer effectively suppresses chemical corrosion and hydrogen evolution reactions and enables preferential(002)Zn deposition during the stripping/plating ***,the Cu@Zn anode represents an elongated cycle life over 4,000 h at 2 mA·cm^(-2)/2 mAh·cm^(-2).Even in conditions of high current density of 5 and 10 mA·cm^(-2),the Cu@Zn anode shows prolonged cycling stability exceeding 4000 and 2000 h,*** advantages also bring high Coulombic efficiency of 99.87%under 5 mAh·cm^(-2)in Cu@Ti||Zn half-cell over 1500 ***,the Cu@Zn||MnO_(2)full cell demonstrates a superior cyclability with a specific capacity of 203 mAh·g^(-1)after 500 cycles a1 A·g^(-1).

关键词： Zn ion battery Zn metal anode Zn(002)plane Cu coating