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Non-spherical symmetry development of underwater shock waves created by laser-induced breakdown

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Journal of Hydrodynamics 2023年第1期35卷 76-82页

作者： Ying-xue wang Di-xi Han Jian-hua Liu Qiang Zhong Zhi-feng Yao Ruo-fu Xiao fu-jun wang College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China China Ship Scientific Research Centre Wuxi214082China Taihu Laboratory of Deepsea Technological Science Wuxi214082China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China

As a controllable alternative to cavitation collapse-induced shock waves,numerous cavitation studies on laser-induced breakdown have been carried out in *** the laser focusing region is not spherical,the shock waves caused by laser breakdown also exhibit non-spherical symmetry ***,some researchers have proposed the linear superposition theory based on the far field measurement data to explain this asymmetry,assuming that it is essentially the linear superposition of multiple wave fronts caused by multiple points of laser-induced breakdown that leads to the asymmetric propagation of shock *** this study,measurements of shock wave propagation processes with different breakdown energies are carried out based on a nanosecond resolution photogrammetry system,and the propagation velocities of shock waves in different directions are directly measured using a double exposure technique on a single *** the experiment,the velocity of the shock wave at the beginning of the breakdown was measured up to nearly 4000 m/*** early shock wave front was ellipsoidal,and the propagation velocity in the laser incident direction was generally slower than that in the perpendicular direction,decaying to the speed of sound in water within 1000 ns after the breakdown,and the wave front gradually approached to a *** variability of the shock wave front pressure ratio in the laser propagation direction and the vertical direction implies that the linear superposition theory applicable to the far field is not applicable to the near *** may be more complex mechanism for the near-field shock wave propagation process.

关键词： Underwater shock wave non-spherical symmetry velocity decay linear superposition laser breakdown

Adaptive Noise Identification in Vision-assisted Motion Estimation for Unmanned Aerial Vehicles

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International Journal of Automation and computing 2015年第4期12卷 413-420页

作者： Fan Zhou Wei Zheng Zeng-fu wang Department of Automation University of Science and Technology of China Institute of Intelligent Machines Chinese Academy of Sciences

Vision localization methods have been widely used in the motion estimation of unmanned aerial vehicles(UAVs).The noise of the vision location result is usually modeled as a white Gaussian noise so that this location result could be utilized as the observation vector in the Kalman filter to estimate the motion of the *** the noise of the vision location result is affected by external environment,the variance of the noise is ***,in previous researches,the variance is usually set as a fixed empirical value,which will lower the accuracy of the motion *** main contribution of this paper is that we proposed a novel adaptive noise variance identification(ANVI) method,which utilizes the special kinematic properties of the UAV for frequency analysis and then adaptively identifies the variance of the *** adaptively identified variance is used in the Kalman filter for more accurate motion *** performance of the proposed method is assessed by simulations and field experiments on a quadrotor *** results illustrate the effectiveness of the method.

关键词： Adaptive noise variance identification vision location motion estimation Kalman filter unmanned aerial vehicle.

Adsorption of Au(Ⅲ) by amino-modified monodispersed PGMA microspheres and deposition of gold nanoparticles

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Rare Metals 2018年第3期37卷 196-203页

作者： fu-Chun wang Jun-Mei Zhao Wan-Kun wang Zi-Zheng Tong School of Materials and Metallurgical Engineering Guizhou Institute of Technology Institute of Process Engineering Chinese Academy of Sciences

Monodispersed poly（glycidyl methacrylate）（PGMA） microspheres with various amounts of amino groups（PGMA-NH2） were used to adsorb Au（Ⅲ） from simulated wastewaters. Gold nanoparticle-coated PGMA functional microspheres can be directly obtained via the adsorption process. The adsorption kinetics follows pseudo-second model, and 10 min is enough for reaching at equilibrium. The adsorption isotherm follows Langmuir model, and the adsorption amounts for Au（Ⅲ） are 8.25 and 21.75 mol·kg^-1 at 298 and 328 K, respectively. The relative separation coefficients between Au（Ⅲ）, Pt（Ⅵ）, Pd（Ⅱ）and Co（Ⅱ）, Cu（Ⅱ）; Ni（Ⅱ）, Fe（Ⅲ） are all higher than 100 when 1 〈 pH 〈 3. furthermore, the characterization analysis of X-ray diffraction（XRD）, thermogravimetrydifferential scanning calorimetry（TG-DSC）, scanning electron microscopy-energy dispersive spectroscopy（SEM-EDS）, transmission electron microscopy（TEM） and Fourier transform infrared spectroscopy（FTIR） confirms that AuCl4^-has been reduced to Au^0 nanoparticles and deposited onto the surface of PGMA-NH2. The current work shows a good prospect for PGMA-NH2 to be a valid adsorbent for the recovery of gold and the possible fabrication of gold nanoparticles by reduction-deposition process without any reductant.

关键词： PGMA microspheres AuCl4^- Amino groups Adsorption Reduction-deposition Elemental gold

Characteristics of supersonic flow in new type externally pressurized spherical air bearings

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Journal of Central South University 2012年第1期19卷 128-134页

作者： wang fu-sheng BAO Gang School of Mechanical and Electrical Engineering Harbin Institute of TechnologyHarbin 150001China

In order to predict accurately the characteristics of supersonic flow in new type externally pressurized spherical air bearings under large bearing clearance and high air supply pressure, which could decrease their load carrying capacity and stability, a CFD-based analysis was introduced to solve the three-dimensional turbulent complete compressible air flow governing equations. The realizable κ-ε model was used as a turbulent closure illustrate that the interaction exists between shock waves The supersonic flow field near air inlets was analyzed. The flow structures and boundary layer, and the flow separation is formed at the lower comer and the lower wall around the point of a maximum velocity. The numerical results show that the conversion from supersonic flow to subsonic flow in spherical air bearing occurs through a shock region （pseudo-shock）, and the viscous boundary layer results in the flow separation and reverse flow near the shock. The calculation results basically agree with the corresponding experimental data.

关键词： supersonic flow spherical air bearings Mach number shock wave

Fabrication and properties of aluminum silicate fibrous materials with in situ synthesized K2Ti6O13 whiskers

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International Journal of Minerals,Metallurgy and Materials 2017年第11期24卷 1335-1340页

作者： Hao Liu Nan Wei Zhou-fu wang Xi-tang wang Yan Ma The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China

To improve their mechanical and thermal insulation properties, aluminum silicate fibrous materials with in situ synthesized K_2Ti_6O_(13) whiskers were prepared by firing a mixture of short aluminum silicate fibers and gel powders obtained from a sol–gel process. During the preparation process, the fiber surface was coated with K_2Ti_6O_(13) whiskers after the fibers were subjected to a heat treatment carried out at various temperatures. The effects of process parameters on the microstructure, compressive strength, and thermal conductivity were analyzed systematically. The results show that higher treatment temperatures and longer treatment durations promoted the development of K_2Ti_6O_(13) whiskers on the surface of aluminum silicate fibers; in addition, the intersection structure between whiskers modulated the morphology and volume of the multi-aperture structure among fibers, substantially increasing the fibers' compressive strength and reducing their heat conduction and convective heat transfer at high temperatures.

关键词： aluminum silicate fiber potassium hexatitanate whiskers compressive strength thermal conductivity

Boosting viral-specific immunotherapy for chronic hepatitis B treatment

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Cellular & Molecular Immunology 2021年第12期18卷 2586-2587页

作者： Jin Fan Jun-Liang fu fu-Sheng wang Senior Department of Infectious Diseases the Fifth Medical Center of PLA General HospitalNational Clinical Research Center for Infectious DiseasesBeijing100039China

Hepatitis B virus(HBV)-specific antibody-producing B cells and functional HBV-specific helper and cytotoxic T cells are the primary influence of the clinical outcome of acute or chronic HBV ***,patients with chronic h... 详细信息

关键词： acute hepatitis clinical

Processing and oxidation of co-deposited Ni-Al coatings

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中国有色金属学会会刊：英文版 2004年第z1期14卷 199-203页

作者： ZHOU Yue-bo PENG Xiao wang fu-hui State Key Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences Shenyang 110016 China State Key Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences Shenyang 110016 China State Key Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences Shenyang 110016 China

Electrodeposited Ni matrix/Al microparticles or nanoparticles dispersed composite coatings (termed as EMCCs or ENCCs) are developed from a Ni-based electrolyte bath. The Al microparticles are in a size range of 1 -5 μm and the Al nanoparticles in an average size of 75 nm. The Al content in coatings increases with increase in the particle content in the bath. Particle size effect on the degree of codeposition is not significant. However, codeposition of Al nanoparticles instead of microparticles promotes more homogenous growth of Ni deposits on {111}, {200} and {220} planes. The oxidation at 1 050 ℃ of the as-deposited composite coatings shows that at a comparable Al content, ENCC of Ni-Al exhibits a better oxidation resistance than EMCC of Ni-Al due to the fast formation of an alumina scale during the transient stage of oxidation.

关键词： electrodeposition co-deposition Ni-Al composite coating high temperature oxidation microparticle nanoparticle

Arc-Discharge Synthesis and Microstructure Characterization of AIN Nanowires

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Journal of Materials Science & Technology 2006年第1期22卷 113-116页

作者： Zhijie LI Zhiqi SHEN fu wang Lianlong HE Shenyang National Laboratory of Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China Laboratory of Ultra-fine Particle Shenyang University of Technology Shenyang 110023 China School of Materials and Metallurgy Northeastern University Shenyang 110004 China

AIN nanowires with a hexagonal structure were synthesized using an improved arc-discharge method and their microstructures were characterized using a high-resolution transmission electron microscope. The synthesized AIN nanowires were of various shapes. Their diameters ranged from 20 to 110 nm and the lengths were up to 20 μm. Most of the AIN nanowires were coated by an amorphous layer of aluminum oxide. Fabrication yield was about several grams. The growth mechanism was considered to be a vapor-liquid-solid process and an AI droplet formed on the top of as-grown AIN nanowire played a role of catalyst.

关键词： Arc-discharge Nanowire High-resolution transmission electron microscope(HRTEM)

Low Frequency Electromagnetic Casting of 2195 Aluminum-Lithium Alloy and Its Effects on Microstructure and Mechanical Properties

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Acta Metallurgica Sinica(English Letters) 2020年第3期33卷 338-350页

作者： fu-Yue wang Xiang-Jie wang Wei Sun Fang Yu Jian-Zhong Cui Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China

In this study,the low frequency electromagnetic casting(LFEC) technology was adopted to fabricate 2195 Al-Li *** microstructure and solid solubility of as-cast 2195 alloys,as well as the second phase precipitation and tensile properties after aging,were investiagated and compared with the counterpart direct chill casting 2195 *** results indicate that LFEC can significantly improve the microstructure and metallurgical quality of as-cast alloy,and increase the number density of θ’(Al2Cu) and T1(Al2CuLi) phases during aging treatment due to the enhanced solubilities of alloying *** tensile properties of 2195 aged alloy cast by LFEC were hence improved evidently.

关键词： LFEC(low frequency electromagnetic casting) 2195 Aluminum-lithium alloy Casting defects Microstructure Tensile property