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A review of biomimetic research for erosion wear resistance

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Bio-Design and Manufacturing 2020年第4期3卷 331-347页

作者： feng sun He Xu College of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbinChina

One of the reasons behind failed engineering surfaces and mechanical components is particle erosion wear;thus,to mitigate its happening,biomimetic engineering is the current state-of-the-art being ***,this paper reviews the literature and the development trends on erosive wear resistance that employ biomimetic methods as well as analyze the bio-inspired surface,the bio-inspired structure,the bio-based materials,the associated challenges,and the future ***,the feasibility of the multi-biological and perspective on the coupling biomimetic method for anti-erosion wear are *** is concluded that the design of anti-erosion materials or structures by the bio-inspired methods is of great significance in the development of engineering applications.

关键词： Erosion wear Biology to engineering Biomimetics Erosion reduction

Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

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Journal of Thermal Science 2024年第1期33卷 126-137页

作者： sun feng XIE Gongnan School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Department of Thermal Engineering Tsinghua UniversityBeijing 100084China

Active regenerative cooling with supercritical hydrocarbon fuel is considered as the most promising thermal protection *** existence of buoyancy force would lead to strongly anisotropic flow and thermal transport *** is closely related to the cooling performance of the *** elucidate the mechanisms of turbulent transport,the large eddy simulation(LES) was performed to assess turbulence statistics within different turbulence *** results indicated that the buoyancy and inertial force together dominated the change of turbulent ***,the spatial thermal buoyancy effect significantly suppressed the vertical velocity *** is due to the laminar motion caused by the buoyancy force,thereby weakening the thermal *** the statistics of velocity fluctuation,it was found that the buoyancy force and inertial force greatly weaken the vertical and streamwise velocity fluctuation,*** the statistics of thermal transport,the results pointed out that the near-wall heat transport characteristics need to be paid more *** thickness of the temperature mixing boundary layer led to the attenuation of vertical heat flux,which inhibited vertical temperature diffusion and predisposed to extreme conditions of heat transfer *** results can enhance the academic understanding of the heat transfer mechanism of supercritical fluids,and give guidance for further applications of thermal protection.

关键词： active regenerative cooling large eddy simulation(LES) buoyancy force turbulence statistics

Selberg＇s Integral for Ramanujan Automorphic Representation

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Acta Mathematica Sinica,English Series 2011年第7期27卷 1449-1454页

作者： Qing feng sun Department of Mathematics Shandong University Ji'nan 250100 P. R. China

Let π△ be the automorphic representation of GL（2, QA） associated with Ramanujan modular form A and L（s, π△） the global L-function attached to π△. We study Selberg＇s integral for the automorphic L-function L（s, π△） under GRH. Our results give the information for the number of primes in short intervals attached to Ramanujan automorphic representation.

关键词： Automorphic L-functions Selberg's integral primes in short intervals

Trajectory Analysis of Fuel Injection into Supersonic Cross Flow Based on Schlieren Method

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Chinese Journal of Aeronautics 2012年第1期25卷 42-50页

作者： YANG Hui LI feng sun Baigang School of Jet Propulsion Beihang University Beijing 100191 China

Trajectory analysis of fuel injection into supersonic cross flow is studied in this paper. A directly-connected wind tunnel is constructed to provide stable supersonic freestream. Based on the test rig, the schlieren system is established to reveal the fuel injection process visually. Subsequently, the method of quantitative schlieren is adopted to obtain data of both fuel/air interface and bow shock with the aid of Photoshop and Origin. Finally, the mechanism based on two influential factors of fuel injection angle and fuel injection driven pressure, is researched by vector analysis. A dimensionless model is deduced and analyzed. The curve fitting result is achieved. The relationship between the data and the two influential factors is established. The results provide not only the quantitative characteristics of the fuel injection in supersonic cross flow but also the valuable reference for the future computational simulation.

关键词： fuel injection schlieren supersonic flow injection driven pressure injection angle characteristic velocity

Synthesis and Structure of [Cu(OH)_2(H_2O)_2(4-C_5H_4N-COOH)_2]

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Chinese Journal of Structural Chemistry 2001年第6期20卷 478-480页

作者： ZHONG Zhao-En sun Dao-feng South China Medical Apparatus Coorporation Ltd. Tonghe TownTongsha Road 13Guangzhou 510515China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian 350002China

The hydrothermal reaction of isonicotinic acid (4-C5H4N-COOH), Cu(ClO4)(2). 6H(2)O and water at 170 degreesC gave the title compound, [Cu(OH)(2)(H2O)(2)(4-C5H4N-COOH)(2)] (1), which was analyzed by single-crystal X-ray diffraction, The complex crystallizes in triclinic space group PY with unit cell parameters: a = 6.337(2), b = 6.894(3), c = 9.178(3). alpha = 99.40(3), beta = 105.26(3), gamma 108.17(5)degrees, V = 354.1(2)Angstrom (3), Z = 1, C12H16CuN2O8, M-r = 379.81, D-c = 1.791 Mg/m(3), F(000) 197, mu (MoK alpha) = 1.589 mm(-1). The final R and wR are 0.068 and 0.170 for 1249 observed reflections with I greater than or equal to2 sigma (I). The central copper ion is in a distorted octahedron geometry completed by two nitrogen atoms from carboxylic ligand, two oxygen atoms from hydroxyl groups and two oxygen atoms from coordinated water molecules. The intermolecular hydrogen bonding leads to the formation of a three-dimensional supramolecular structure.

关键词： hydrothermal reaction copper complex intermolecular hydrogen bonding

Molecular-Dynamics Simulations of Droplets on a Solid Surface

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Chinese Physics Letters 2010年第6期27卷 152-155页

作者： GAO Yu-feng sun De-Yan Department of Physics East China Normal University Shanghai 200062

By using a semi-empirical Lennard-Jones embedded-atom-method potential, we study the influence of many-body forces and atomic size mismatch on the wetting behavior of nano droplets on a solid surface. With molecular dynamics simulations, we find that the contact angle decreases with increasing many-body forces. The increase of atomic size mismatch between solid and liquid results in the decrease of contact angles. Our calculation also shows that the interface structure is strongly affected by the interaction between liquid and solid as well as the atomic size mismatch. For weak solid-liquid interaction, the interface layer of the droplet nearest to the solid exhibits a typical simple liquid structure regardless of the size mismatch. For strong solid-liquid interaction, evident ordering in the interface layer is observed for well matched cases.

关键词： MOLECULAR dynamics SIMULATION methods & models SURFACES (Technology) EMPIRICAL research ATOMIC theory FORCE & energy INTERFACES (Physical sciences)

Realization of arbitrary two-qubit quantum gates based on chiral Majorana fermions

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Chinese Physics B 2021年第4期30卷 43-54页

作者： Qing Yan Qing-feng sun International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China Collaborative Innovation Center of Quantum Matter Beijing 100871China Beijing Academy of Quantum Information Sciences Beijing 100193China

Quantum computers are in hot-spot with the potential to handle more complex problems than classical computers *** the quantum computation requires the universal quantum gate set {T,H,CNOT} so as to perform any unitary transformation with arbitrary *** we first briefly review the Majorana fermions and then propose the realization of arbitrary two-qubit quantum gates based on chiral Majorana *** cells consist of a quantum anomalous Hall insulator surrounded by a topological superconductor with electric gates and quantum-dot structures,which enable the braiding operation and the partial exchange *** defining a qubit by four chiral Majorana fermions,the singlequbit T and H quantum gates are realized via one partial exchange operation and three braiding operations,*** entangled CNOT quantum gate is performed by braiding six chiral Majorana ***,we design a powerful device with which arbitrary two-qubit quantum gates can be realized and take the quantum Fourier transform as an example to show that several quantum operations can be performed with this space-limited ***,our proposal could inspire further utilization of mobile chiral Majorana edge states for faster quantum computation.

关键词： quantum computation T gate CNOT gate braiding chiral Majorana fermions

Anomalous Josephson current in quantum anomalous Hall insulator-based superconducting junctions with a domain wall structure

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Chinese Physics B 2020年第9期29卷 487-497页

作者： Qing Yan Yan-feng Zhou Qing-feng sun International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China Department of Physics University of Texas at DallasRichardsonTexas 75080USA CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

We theoretically study the Josephson effect in a quantum anomalous Hall insulator(QAHI)nanoribbon with a domain wall structure and covered by the *** anomalous Josephson current,the nonzero supercurrent at the zero superconducting phase difference,appears with the nonzero magnetization and the suitable azimuth angle of the domain *** on the configuration of the domain wall,the anomalous current peaks in the Bloch type but disappears in the Néel type because the y-component of magnetization is necessary to break symmetry to arouse the anomalous *** phase shift of the anomalous current is tunable by the magnetization,the azimuth angle,or the thickness of the domain *** introducing a bare QAHI region in the middle of the junction which is not covered by the superconductor,the anomalous Josephson effect is enhanced such that the phase shift can exceedπ.Thus,a continuous change between 0 andπjunctions is realized via regulating the configuration of the domain wall or the magnetization *** long as an s-wave superconductor is placed on the top of the QAHI with a domain wall structure,this proposal can be experimentally fabricated and useful for the phase battery or superconducting quantum bit.

关键词： anomalous Josephson current quantum anomalous Hall insulator domain wall Josephson junction

On Holomorphic Sections in Teichmiiller Spaces

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Acta Mathematica Sinica,English Series 2009年第12期25卷 2023-2034页

作者： Ming feng sun Yu Liang SHEN Department of Mathematics Soochow University Suzhou 215006 P. R. China

It is proved that, for any elementary torsion free Fuchsian group F, the natural projection from the Teichmiiller curve V（F） to the Teichmiiller space T（F） has no holomorphic section.

关键词： Teichmuller space Bers fiber space Teichmiiller curve holomorphic section punctureforgetting mapping