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Air-coupled ultrasonic testing and analysis on delamination defect of low-density thermal protection and insulation material

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Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica 2025年第2期42卷 835-844页

作者： Xiao, Kedi Ma, zhaoqing Gao, Chenjia Chen, Bo Yuan, Shengping Luo, Ming Zhi, Fan Tang, Jun Yu, Liqiong Wu, Shihong zhao, jianhua Aerospace Research Institute of Materials & Processing Technology Beijing100076 China

The low-density thermal protection and insulation material is an important constituent material on aerospace craft thermal protection system. The material is low density, high porosity, and low thermal conductivity, with lightweight and excellent thermal protection and insulation performance. However, the material and its microscopic structure characteristics cause difficulties on non-destructive testing on the internal defects. The regular ultrasonic transmission testing is unsuitable, and the infrared testing is less effective. To detect the delamination defect of low-density thermal protection and insulation material, which is composed of quartz needled fabric and phenolic resin, the research on air-coupled ultrasonic testing is carried out. The microstructure of the material was analyzed by X-ray Micro-CT detection. The relationship between delamination defect sound pressure transmittance and air gap thickness was estimated. The material specimens with densities of 0.4, 0.5, 0.6, 0.7 g/cm3 were made. The research of air-coupled ultrasonic testing on the specimens with probe frequencies of 50, 140, 200 kHz was performed. The result shows, the air-coupled ultrasonic testing is effective on delamination defect detection of low-density thermal protection and insulation material. The suitable detection frequency and detectability are both related to the material density and the material homogeneity. When the material thickness is 30 mm, the delamination defect air gap thickness is 0.3 mm, the probe frequency is 50 kHz, and the material density is within 0.4-0.7 g/cm3, the delamination defect with diameter greater than 30 mm can be detected. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Ultrasonic testing

Surface modification of die casting mold steel by a composite technique of hot-dipping and plasma electrolytic oxidation

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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

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镀锡层对铜导线超声波焊接接头性能的影响

焊接学报 2025年第2期46卷 95-101页

作者：吕玮怡杨可成先明赵健华冯博河海大学材料科学与工程学院常州213200

对镀锡铜导线、铜导线进行超声波焊接试验,观测镀锡铜导线、铜导线焊接接头温度,分析了不同焊接能量下镀锡铜导线、铜导线焊接接头的性能,研究了镀锡层对铜导线超声波焊接接头性能的影响.结果表明,超声波焊接可以实现镀锡铜导线有效连接... 详细信息

对镀锡铜导线、铜导线进行超声波焊接试验,观测镀锡铜导线、铜导线焊接接头温度,分析了不同焊接能量下镀锡铜导线、铜导线焊接接头的性能,研究了镀锡层对铜导线超声波焊接接头性能的影响.结果表明,超声波焊接可以实现镀锡铜导线有效连接,随着焊接能量的增加,镀锡铜导线、铜导线两种导线的焊接接头抗拉力逐渐增加;由于镀锡层的熔点较低,在超声软化作用下填充铜导线界面,进而隔离铜线之间原子扩散渗透,使得不同焊接能量下的镀锡铜导线的强度明显低于铜导线;随着焊接能量增加,焊接界面温度升高,镀锡铜导线表面镀锡层熔化,镀锡铜铜丝直接连接产生冶金结合,强度增加明显,其焊接接头断口出现韧窝,显示出明显的韧性断裂模式,接头性能较好.

关键词：超声波焊接镀锡铜线铜线力学性能

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