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Rare Metals 2012年第4期31卷 362-367页

作者： zhao, Guohua zhao, jianhua College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400045China

The hot dipping process of pure aluminum on H13 steel substrates followed by plasma electrolytic oxidation(PEO) was studied to form alumina ceramic coatings for protective purpose.H13 steel bars were first dipped in pure aluminum melts,and then,a reactive iron-aluminum intermetallic layer grew at the interface between the melt and the steel *** reactive layer was mainly composed of intermetallic Fe-Al(Fe_2Al_5);the thickness of aluminum layer and Fe-Al intermetallic layer were mainly influenced by dipping time(1.5～12.0 min) and dipping temperature(710～760 ℃).After PEO process,uniform Al_2O_3 ceramic coatings were deposited on the surface of aluminized *** element distribution,phase composition and morphology of the aluminized layer,and the ceramic coatings were characterized by SEM/EDS and *** distribution of hardness across the composite coating is demonstrated,and the maximum value reaches 1864 *** thermal shock resistance of the coated sample is also well improved.

关键词： plasma electrolytic oxidation hot-dipping aluminum surface modification

Measurement of thermal conductivity,viscosity and density of ionic liquid [EMIM][DEP]-based nanofluids

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Chinese Journal of Chemical Engineering 2016年第3期24卷 331-338页

作者： Hua Xie Zongchang zhao jianhua zhao Hongtao Gao School of Chemical Engineering Dalian University of Technology Institute of Marine Engineering and Thermal Science Dalian Maritime University

This article studied experimentally the effect of multi-wall carbon nanotubes （MWCNTs） on the thermo physical properties of ionic liquid-based nanofluids. The nanofluids were composed of ionic liquid, 1-ethyl-3- methylimidazolium diethylphosphate [EMIM][DEP], or its aqueous solution[EMIM][DEP]（1）＋ H20（2） and MWCNTs without any surfactants. The thermal conductivity, viscosity and density of the nanofluids were mea- sured experimentally. The effects of the mass fraction of MWCNTs, temperature and the mole fraction of water on the thermo physical properties of nanofluids were studied. Results show that the thermal conductivity of nanofluids increases within the range of 1.3%-9.7% compared to their base liquids, and have a well linear depen- dence on temperature. The viscosity and density of the nanofluids exhibit a remarkable increase compared with those of the base liquids. Finally, the correlation of the effective thermal conductivity and viscosity of the nanofluids was made using the models in the literatures.

关键词： Nanofluid Multi-wall carbon nanotubes Thermal conductivity Viscosity Density

Oil Pocket's Bearing Capacity Analysis of Liquid Hydrostatic Worktable in Gantry Moving Milling Center

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 1008-1017页

作者： zhao jianhua LIANG Yingna GAO Dianrong Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Liren College Yanshan University

Durning the design process of hydrostatic rotary worktable,the processing and assembly tolerance,（the offset of worktable and the gap of the oil film’s thickness）is *** it will cause that the real bearing of oil pocket deviates from the initial design value,and then the performance of rotary worktable will be reduced *** to now,no effort is found toward the research of influence of the processing and assembly tolerance on the performance of the rotary *** the hydrostatic oil film is assumed as the elastomer in this paper,and then the bearing capacity of the oil pocket is studied with and without the mass offset of the worktable by taking an expression between the bearing capacity and the oil film’s thickness of the oil pocket as the deform compatibility *** influence of the processing tolerance of the oil sealing belt’s gap on the bearing capacity of the oil pocket is *** the light of the liquid hydrostatic worktable of Gantry Moving Milling Center using on the scene,the oil pocket’s pressure of the worktable is tested using Rotary Worktable Test System under the circumstance of the mass offset of the worktable and the gap tolerance of the oil sealing belt,and then the equivalent offset of worktable,the average pressure of the oil pocket and the actual thickness of the oil film are analyzed *** test results show that the bearing capacity component of the oil pocket caused by G is consistent,and the component caused by M is relative to the position of the oil *** the oil sealing belt’s gap is larger than the theoretical value,the bearing capacity of the oil pocket is smaller than the others;whereas the bearing capacity of the oil pocket is larger than the *** maximum and minimum equivalent offsets are 0.256 4 mm and 0.047 5 mm,respectively,and the average oil pocket pressure varies from 0.345 MPa to 0.460 MPa,the maximum and minimum value of the actual oil film thickness are 109.976？m（No.7 oil

关键词： Gantry Moving Milling Center bearing capacity processing and assembly tolerance mass offset

Simplified iterative algorithm for OFDM phase noise mitigation

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Journal of Systems Engineering and Electronics 2007年第4期18卷 716-720页

作者： Yang jianhua zhao Danfeng Yue Li zhao Chunhui Coll. of Information and Communication Engineering Harbin Engineering Univ. Harbin 150001 P. R. China

OFDM has been widely adopted in several communication systems. However, OFDM systems are very sensitive to the phase noise, which causes the CPE （common phase error） and ICI （inter-carrier interference）, and thus degrades the system performance significantly. Based on the IEEE 802.11a standard, a simplified iterative phase noise mitigation algorithm is proposed. The proposed algorithm has very low complexity, and requires no additional pilot information. The simulation result shows that good BER performance can be achieved through several few times of iteration.

关键词： phase noise OFDM systems IEEE 802.11a standard inter-carrier interference

Electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases epitaxied on GaAs (001) substrates

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Journal of Semiconductors 2022年第7期43卷 55-60页

作者： Qiqi Wei Hailong Wang Xupeng zhao jianhua zhao State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China

The electron mobility anisotropy in (Al,Ga)Sb/InAs two-dimensional electron gases with different surface morphology has been *** electron mobility anisotropy is found for the sample with anisotropic morphology,which is mainly induced by the threading dislocations in the InAs *** the samples with isotropic morphology,the electron mobility is also anisotropic and could be attributed to the piezoelectric *** low temperature (below transition temperature),the piezoelectric scattering is enhanced with the increase of temperature,leading to the increase of electron mobility *** high temperature (above transition temperature),the phonon scattering becomes *** the phonon scattering is isotropic,the electron mobility anisotropy in all the samples would be *** results provide useful information for the comprehensive understanding of electron mobility anisotropy in the (Al,Ga)Sb/InAs system.

关键词： molecular-beam epitaxy (Al Ga)Sb/InAs two-dimensional electron gases electron mobility anisotropy piezoelectric scattering

A probabilistic-based method to evaluate hygrothermal performance of an internally insulated brick wall

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Building Simulation 2021年第2期14卷 283-299页

作者： jianhua zhao Jianshun Zhang John Grunewald Shuo Feng Institute of Architectural Technology&Science School of ArchitectureTianjin UniversityTianjinChina College of Mechanical&Aerospace Engineering Syracuse UniversitySyracuseUSA Institute of Building Climatology School of ArchitectureTechnische Universität DresdenDresdenGermany Qinhuangdao Municipal Bureau of Foreign Affairs and Commerce QinhuangdaoChina

Uncertainty exists in many aspects of building simulation.A deterministic hygrothermal analysis may not sufficiently give a reliable guidance if a number of input variables are subject to *** this paper,a probabilistic-based method was developed to evaluate the hygrothermal performance of building *** approach accounts for the uncertainties from model inputs and propagates them to the outputs through the simulation model,thus it provides a likelihood of performance *** hypercube sampling technique,incorporated with correlation structure among the inputs,was applied to generate the random samples that follows the intrinsic *** performance of an internally insulated masonry wall was evaluated by applying the proposed approach against different *** performance,condensation and mould growth potential of the renovated wall can overall satisfy the requirements stipulated in multifold *** most influential inputs were identified by the standardized regression sensitivity analysis and partial correlation *** methods deliver the same key parameters for the single and time-dependent output variables in the case *** probabilistic method can provide a comprehensive risk analysis and support the decision-maker and engineer in the design and optimization of building components.

关键词： probabilistic approach hygrothermal performance building component uncertainty analysis sensitivity analysis

Enhancement of the Curie temperature of ferromagnetic semiconductor(Ga,Mn)As

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Science China(Physics,Mechanics & Astronomy) 2013年第1期56卷 99-110页

作者： WANG HaiLong CHEN Lin zhao jianhua State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences

In this review article,we review the progress made in the past several years mainly regarding the efforts devoted to increasing the Curie temperature(T C) of(Ga,Mn)As,which is most widely considered as the prototype ferromagnetic *** Mn doping,nanostructure engineering and post-growth annealing which increase T C are described in detail.

关键词： magnetic semiconductors magnetic properties of nanostructures magnetotransport phenomena molecular-beam epitaxy

Numerical Simulation and Experimental Study of Heat-fluid-solid Coupling of Double Flapper-nozzle Servo Valve

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 1030-1038页

作者： zhao jianhua ZHOU Songlin LU Xianghui GAO Dianrong Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Hebei Vocational & Technical College of Building Materials

The double flapper-nozzle servo valve is widely used to launch and guide the equipment. Due to the large instantaneous flow rate of servo valve working under specific operating conditions, the temperature of servo valve would reach 120℃ and the valve core and valve sleeve deform in a short amount of time. So the control precision of servo valve significantly decreases and the clamping stagnation phenomenon of valve core appears. In order to solve the problem of degraded control accuracy and clamping stagnation of servo valve under large temperature difference circumstance, the numerical simulation of heat-fluid-solid coupling by using finite element method is done. The simulation result shows that zero position leakage of servo valve is basically impacted by oil temperature and change of fit clearance. The clamping stagnation is caused by warpage-deformation and fit clearance reduction of the valve core and valve sleeve. The distribution roles of the temperature and thermal-deformation of shell, valve core and valve sleeve and the pressure, velocity and temperature field of flow channel are also analyzed. Zero position leakage and electromagnet＇s current when valve core moves in full-stroke are tested using Electro-hydraulic Servo-valve Characteristic Test-bed of an aerospace sciences and technology corporation. The experimental results show that the change law of experimental current at different oil temperatures is roughly identical to simulation current. The current curve of the electromagnet is smooth when oil temperature is below 80℃, but the amplitude of current significantly increases and the hairy appears when oil temperature is above 80℃. The current becomes smooth again after the warped valve core and valve sleeve are reground. It indicates that clamping stagnation is caused by warpage-deformation and fit clearance reduction of valve core and valve sleeve. This paper simulates and tests the heat-fluid-solid coupling of double flapper-nozzle servo valve, an

关键词： double flapper-nozzle servo valve heat-fluid-solid coupling numerical simulation warpage-deformation clamping stagnation zero position leakage

Friction and Wear Study on Friction Pairs with a Biomimetic Non-smooth Surface of 316L Relative to CF/PEEK under a Seawater Lubricated Condition

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Chinese Journal of Mechanical Engineering 2019年第4期32卷 47-60页

作者： Yingna Liang Dianrong Gao Bo Chen jianhua zhao School of Mechanical Engineering Yanshan University Qinhuangdao 066004China Liren College Yanshan University Qinhuangdao 066004 China Heibei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao 066004 China

Current studies of a seawater axial piston pump mainly solve the problems of corrosion and wear in a slipper pair by selecting materials with corrosion resistance, self-lubrication, and wear resistance. In addition, an appropriate biomimetic non-smooth surface design for the slipper pair can further improve the tribological behavior. In this paper, 316 L stainless steel and CF/PEEK were selected to process the upper and bottom specimens, and the biomimetic non-smooth surface was introduced into the interface between the friction pair. The friction and wear tests were performed on a MMD-5 A tester at a rotation speed of 1000 r/min and load of 200 N under seawater lubricated condition. The results indicate that the main friction form of the smooth surface friction pair corresponds to abrasive wear and adhesive wear and that it exhibits a friction coe cient of 0.05–0.07, a specimen temperature of 56 ℃, a high wear rate, and surface roughness. Pits on the non-smooth surface friction pairs produced hydrodynamic lubrication and reduced abrasive wear, and thus the plowing e ect is their main friction form. The non-smooth surface friction pairs exhibit a friction coe cient of 0.03–0.04, a specimen temperature of 48 ℃, a low wear rate, and surface roughness. The study has important theoretical significance for enriching the lubrication, friction, and wear theory of a seawater axial piston pump, and economic significance and military significance for promoting the marine development and the national defense military.

关键词： Biomimetic non-smooth surface 316L CF/PEEK Seawater lubrication Friction and wear

Improvement of Microstructure and Mechanical Properties of Rapid Cooling Friction Stir-welded A1050 Pure Aluminum

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 134-141页

作者：许楠 LIU Lutao SONG Qining zhao jianhua BAO Yefeng College of Materials Science and Engineering Hohai UniversityChangzhou 213200China

Two-mm thick A1050 pure aluminum plates were successfully joined by conventional and rapid cooling friction stir welding(FSW), respectively. The microstructure and mechanical properties of the welded joints were investigated by electron backscatter diffraction characterization, Vickers hardness measurements, and tensile testing. The results showed that liquid CO_(2) coolant significantly reduced the peak temperature and increased the cooling rate, so the rapidly cooled FSW joint exhibited fine grains with a large number of dislocations. The grain refinement mechanism of the FSW A1050 pure aluminum joint was primarily attributed to the combined effects of continuous dynamic recrystallization, grain subdivision, and geometric dynamic recrystallization. Compared with conventional FSW, the yield strength, ultimate tensile strength, and fracture elongation of rapidly cooled FSW joint were significantly enhanced, and the welding efficiency was increased from 80% to 93%. The enhanced mechanical properties and improved synergy of strength and ductility were obtained due to the increased dislocation density and remarkable grain refinement. The wear of the tool can produce several WC particles retained in the joint, and the contribution of second phase strengthening to the enhanced strength should not be ignored.

关键词： aluminum alloy friction stir welding recrystallization microstructure mechanical properties