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Phonon Stability of Quantum Droplets in Dipolar Bose Gases

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Chinese Physics Letters 2022年第6期39卷 52-57页

作者： Fan Zhang lan Yin School of Physics Peking UniversityBeijing 100871China

Stabilized by quantum fluctuations,dipolar Bose–Einstein condensates can form self-bound liquid-like *** in the Bogoliubov theory,there are imaginary phonon energies in the long-wavelength limit,implying dynamical instability of this system.A similar instability appears in the Bogoliubov theory of a binary quantum droplet,and is removed due to higher-order quantum fluctuations as shown recently[Gu Q and Yin L 2020 ***.B 102220503(R)].We study the excitation energy of a dipolar quantum droplet in the Beliaev formalism,and find that quantum fluctuations significantly enhance the phonon *** adopt a self-consistent approach without the problem of complex excitation energy in the Bogoliubov theory,and obtain a stable anisotropic sound velocity which is consistent with the superfluid hydrodynamic theory,but slightly different from the result of the extended Gross–Pitaevskii equation due to quantum depletion.A modified Gross–Pitaevskii equation in agreement with the Beliaev theory is proposed,which takes the effect of quantum fluctuations into account more completely.

关键词： stability quantum excitation

Experimental and Numerical Studies on Sea Sand Concrete Filled Stainless Steel Tube with Inner FRP Tube Subjected to Axial Compression

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China Ocean Engineering 2023年第2期37卷 272-287页

作者： ZENG lan YU Wen-lan MO Zi-yong HUANG Shi-qing YUAN Hong MOE Key Laboratory of Disaster Forecast and Control in Engineering School of Mechanics and Construction EngineeringJinan UniversityGuangzhou 510632China Construction Engineering Quality and Safety Supervision Station of Renshou County Meishan 620500China School of Architectural Engineering Guangzhou Institute of Science and TechnologyGuangzhou 510540China

Since fibre-reinforced polymer(FRP) and stainless steel(SS) offer advantages of corrosion resistance and hybrid confinement, this study proposed a new type of composite column: sea sand concrete(SSC)-filled SS tubular columns with an inner FRP tube(CFSTFs) to help exploit abundant ocean resources in marine engineering. To study compressive behaviours of these novel members, eight CFSTFs and two SSC-filled SS tubular columns(CFSTs)were tested under axial compression. Their axial load-displacement curves, axial load-strain curves in SS or FRP tubes were obtained, and influences of key test parameters(the existence of glass FRP(GFRP) tubes, steel tube shapes, and GFRP tube thicknesses and diameters) were discussed. Further, specimen failure mechanism was analyzed employing the finite element method using ABAQUS software. Test results confirmed the excellent ductility and load-bearing capacity of CFSTFs. The existence of GFRP tubes inside can postpone SS tube buckling, and the content of inner FRP tubes, particularly increasing diameters, was found to improve compressive behaviours. GFRP contents helped develop the second elastic-plastic stage of the load-displacement curves. Furthermore, the bearing capacity of CFSTFs with a circular cross-section was approximately 26% higher than that with a square cross-section, and this difference narrowed with the increase in GFRP ratios.

关键词： sea-sand concrete(SSC) confined concrete column fibre-reinforced polymer(FRP)tube stainless steel tube axial compression

Analytical models for the penetration of semi-infinite targets by rigid,deformable and erosive long rods

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Acta Mechanica Sinica 2010年第4期26卷 573-583页

作者： He-Ming Wen Bin lan CAS Key Laboratory for Mechanical Behavior and Design of Materials University of Science and Technology of China 230027 Hefei China

A theoretical study is presented herein on the pen- etration of a semi-infinite target by a spherical-headed long rod for Yp 〉 S, where Yp is the penetrator strength and S is the static target resistance. For Yp 〉 S, depending upon initial impact velocity, there exist three types of penetration, namely, penetration by a rigid long rod, penetration by a deforming non-erosive long rod and penetration by an erosive long rod. If the impact velocity of the penetrator is higher than the hydrodynamic velocity （VH）, it will penetrate the target in an erosive mode; if the impact velocity lies between the hydrodynamic velocity （VH） and the rigid body velocity （VR）, it will penetrate the target in a deformable mode; if the impact velocity is less than the rigid body velocity （VR）, it will penetrate the target in a rigid mode. The critical conditions for the transition among these three penetration modes are proposed. It is demonstrated that the present model predictions correlate well with the experimental observations in terms of depth of penetration （DOP） and the critical transition conditions.

关键词： Long rod Semi-infinite target - Penetration Alekseevskii-Tate model Rigid body velocity - Hydrodynamic velocity

A direct electrochemical biosensor for rapid glucose detection based on nitrogen-doped carbon nanocages

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Rare Metals 2024年第5期43卷 2184-2192页

作者： lan-lan Li Yu Zhao Li-Jia Pan Jian-Bin Xu Yi Shi College of Mechanical and Electrical Engineering Henan Agricultural UniversityZhengzhou 450002China School of Electronic Science and Engineering Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China Department of Electronic Engineering The Chinese University of HongKongHongkong 999077China

Given the increasing number of diabetic patients,rapid and accurate detection of glucose in body fluids is *** study developed a direct electrochemical biosensor for glucose based on nitrogen-doped carbon nanocages(NCNCs).NCNCs possess a large specific surface area of 1395 m^(2)·g^(-1),a high N atomic content of 9.37%and good biocompatibility,which is favorable for enzyme loading and electron *** surface average concentration of electroactive glucose oxidase on NCNCs was 2.82×10^(-10)mol·cm^(-2).The NCNC-based direct electrochemical biosensor exhibited a high sensitivity of 13.7μA·(mmol·L^(-1))^(-1)·cm^(-2),rapid response time of 5 s and an impressive electron-transferrate constant(ks)of 1.87 s^(-1).Furthermore,we investigated an NCNC-based direct electron transfer(DET)biosensor for sweat glucose detection,which demonstrated tremendous promise for non-invasive wearable diabetes diagnosis.

关键词： Direct electron transfer(DET) Nitrogen-doped carbon nanocages(NCNCs) Glucose oxidase Biosensor

Self-assembling anchored film basing on two tetrazole derivatives for application to protect copper in sulfuric acid environment

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Journal of Materials Science & Technology 2020年第17期52卷 63-71页

作者： Yujie Qiang Hao Li Xijian lan Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China

Two tetrazole compounds(BTA,BTTA)self-assembled on copper substrate and their inhibition effect toward copper corrosion in 0.5 M H2SO4 was evaluated through atomic force microscopy(AFM),scanning electron microscopy(SEM),weight loss measurement along with electrochemical techniques including electrochemical impedance spectroscopy(EIS)and potentiodynamic *** indicate that BTTA can provide superior inhibition performance to BTA,and the highest inhibition efficiency values of 96.3%(BTA)and 99.8%(BTTA)were achieved respectively at 2 *** tetrazole inhibitor films follow langmuir model concerning both physical and chemical adsorption,which can be verified by Xray photoelectronic spectroscopy(XPS)***,the negative value of adsorption free energy infers a spontaneous adsorption process of these tetrazole compounds on Cu *** dynamics(MD)simulation reveals stronger multiple anchor adsorption of BTTA molecules than BTA because of the existence of S atom.

关键词： Copper Corrosion inhibitor Adsorption Anticorrosion MD simulation

Rational design and synthesis of advanced metal-organic frameworks for electrocatalytic water splitting

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Science China Chemistry 2023年第4期66卷 943-965页

作者： Yu-Jia Tang Ya-Qian lan School of Chemistry and Materials Science Institute of Advanced Materials and Flexible Electronics(IAMFE)Nanjing University of Information Science and TechnologyNanjing 210044China School of Chemistry South China Normal UniversityGuangzhou 510006China

As a promising and significant technology for hydrogen production,electrocatalytic water splitting is a research hotspot in the energy conversion field for alleviating the global energy crisis and achieving carbon neutrality ***-organic frameworks(MOFs)have been widely investigated as catalyst candidates with remarkable activity and long-term electrocatalysis durability owing to their precise and tailorable structures:tunable pore channels in the range of micropore/mesopore promote the mass/electron transfer;high specific surface areas expose abundant active species;modified metal nodes can serve as active sites;versatile organic ligands can be functionalized to further enhance the electrocatalytic *** this review,recent advances in the rational design and synthesis of advanced MOF electrocatalysts for water splitting are presented in the following ***,we analyze the design concepts of MOF electrocatalysts from the perspective of their distinct and modifiable ***,three common synthesis techniques of MOF electrocatalysts are briefly ***,we focus on the classification of different MOFs for robust electrocatalytic water splitting,including pristine MOFs,mixed-metallic MOFs,MOF nanosheets,electrically conductive MOFs,MOFs on substrates,and polyoxometalate-based ***,summary and outlook are proposed to uncover the next generation of advanced MOFs for electrochemical energy conversion applications.

关键词： metal-organic frameworks water splitting electrocatalysis hydrogen evolution reaction oxygen evolution reaction polyoxometalates

Aerodynamic Characteristics of a Normal Hovering Foil with Synthetic Jet Actuation

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Journal of Bionic Engineering 2020年第5期17卷 978-988页

作者： Jie Wu lan Jiang Xingjian Lin State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Aerodynamics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China

The aerodynamic characteristics of a normal hovering foil with Synthetic Jet(SJ)actuation are numerically studied in this *** elliptic foil with ratio of 4 undergoes the imposed translation and rotation synchronously.A pair of SJs with the same frequency and strength is placed on the upper and lower surfaces of the ***,the local flow field around the foil would be *** the Reynolds number of 100 and the rotating axis position of half chord,the effects of the inclined angle between the jet direction and the chord line,the phase angle between the SJs and the translation as well as the SJ location on the aerodynamic characteristics are systematically *** with the oscillating foil without SJ actuation,it is illustrated that the enhancement of mean lift force and hovering efficiency can be obtained by using the SJs with suitable working *** on the numerical analysis,it is found that the jet flow on the foil surfaces,which changes the local pressure distribution,can benefit the aerodynamic performance of the hovering foil.

关键词： normal hovering foil translation and rotation synthetic jet lift enhancement

Prof. Huan-Yong Chen： a leading botanist and taxonomist, one of the pioneers and founders of modern plant taxonomy in China

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Protein & Cell 2016年第11期7卷 773-776页

作者： Rui-lan Huang South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China

Prof. Huan-Yong Chen （Woon-Young Chun, 陈焕镛, 1890- 1971）, a leading botanist and taxonomist （Fig. 1）, who started a new era for the modern plant science in China and made a great contribution to the plant taxonomy, botany and horticulture of China, especially in Southern China. He was one of the first academicians of the Chinese Academy of Sciences （CAS）, a member of the first, second and third China＇s National People＇s Congress （NPC）, one of the first editors of Flora of Republicae Popularis Sinicae （FRPS,

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Path Planning for Intelligent Robots Based on Deep Q-learning With Experience Replay and Heuristic Knowledge

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IEEE/CAA Journal of Automatica Sinica 2020年第4期7卷 1179-1189页

作者： lan Jiang Hongyun Huang Zuohua Ding the Laboratory of Intelligent Computing and Software Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China the Center of Multi-Media Big Data of Library Zhejiang Sci-Tech UniversityHangzhou 310018China

Path planning and obstacle avoidance are two challenging problems in the study of intelligent robots. In this paper, we develop a new method to alleviate these problems based on deep Q-learning with experience replay and heuristic knowledge. In this method, a neural network has been used to resolve the "curse of dimensionality" issue of the Q-table in reinforcement learning. When a robot is walking in an unknown environment, it collects experience data which is used for training a neural network;such a process is called experience *** knowledge helps the robot avoid blind exploration and provides more effective data for training the neural network. The simulation results show that in comparison with the existing methods, our method can converge to an optimal action strategy with less time and can explore a path in an unknown environment with fewer steps and larger average reward.

关键词： Deep Q-learning(DQL) experience replay(ER) heuristic knowledge(HK) path planning