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Particle erosion of infrared materials

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Journal of University of Science and Technology Beijing 2008年第6期15卷 758-763页

作者： qi He Fanxiu lv Fenglei Zhang Huibin Guo Junjun Wei School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Erosion test of some infrared （IR） optical crystals （Ge, ZnS, MgF2, and quartz） was conducted with a number of different erodents （glass bead, and angular SiC, SiO2, Al2O3） by a homemade gas-blasting erosion tester. The influence of impact angle, impact velocity, erodent, and erosion time on the erosion rate and the effect of erosion on their IR transmittance were studied. The dam- aged surface morphology was characterized by scanning electron microscopy, and the erosion mechanism was explored. All of the materials show the maximum in wear versus impact angle at 90°, confirming their brittle failure behavior. It is found that the erosion rate is dependent on the erodent velocity by a power law, and it is highly correlated to the hardness of the erodent. The erosion rate-time curves do not show an incubation state, but an accelerated erosion period followed a maximum erosion （steady state）. The decrease of IR transmittance is direct proportion to the erosion rate. Although the material loss occurs primarily by brittle process, ductile behavior is clearly an important feature, especially for MgF2 and ZnS.

关键词： solid particle erosion infrared optical materials erosion mechanism infrared transmittance

Simulation, experimentation, and collaborative analysis of adjacent heat exchange modules in a vehicular cooling system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第6期14卷 417-426页

作者： Yu-qi HUANG Rui HUANG Xiao-li YU Feng lv Power Machinery and Vehicular Engineering Institute Zhejiang University Department of Mechanical and Aerospace Engineering Monash University-Clayton

A cooling system consisting of several heat exchange modules is a necessary part of an automobile, and its performance has a direct effect on a vehicle's energy consumption. Heat exchangers, such as a charged air cooler (CAC), radiator, oil cooler, or condenser have different structures and can be arranged in various orders, and each combination may produce different effects because of interactions among them. In this study, we aimed to explore the principles governing interactions among adjacent heat exchangers in a cooling system, using numerical simulation and experimental technology. 3D models with different combinations were developed, compared, and analyzed comprehensively. A wind tunnel test platform was constructed to validate the computational results. We found that the heat dissipation of the modules was affected slightly by their relative position (the rules basically comply with the field synergy principle), but was independent of the modules' spacing within a certain distance range. The heat dissipation of one module could be effectively improved by restructuring, but with a penalty of higher resistance. However, the negative effect on the downstream module was much less than expected. The results indicated that the intensity of heat transfer depends not only on the average temperature difference between cold and hot mediums, but also on the temperature distribution.

关键词： Collaborative analysis Heat exchangers Field synergy principle Computational fluid dynamics (CFD) Wind tunnel

Enhancing CO_(2)capture of an aminoethylethanolamine-based non-aqueous absorbent by using tertiary amine as a proton-transfer mediator:From performance to mechanism

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Journal of Environmental Sciences 2024年第6期140卷 146-156页

作者： Xiaobin Zhou DanWang chao Liu Guohua Jing Bihong lv Dunqiu Wang College of Environmental Science and Engineering Guilin University of TechnologyGuilin 541004China The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control Guilin University of TechnologyGuilin 541004China College of Chemical Engineering Huaqiao UniversityXiamen 361021China

Non-aqueous absorbents(NAAs)have attracted increasing attention for CO_(2)capture because of their great energy-saving *** diamines which can provide high CO_(2)absorption loading are promising candidates for formulating NAAs but suffer disadvantages in *** this study,a promising strategy that using tertiary amines(TAs)as proton-transfer mediators was proposed to enhance the regenerability of an aminoethylethanolamine(AEEA,diamine)/dimethyl sulfoxide(DMSO)(A/D)***,some employed TAs such as N,N-diethylaminoethanol(DEEA),N,N,N’,N’’,N’’-pentamethyldiethylenetriamine(PMDETA),3-dimethylamino-1-propanol(3DMA1P),and N,N-dimethylethanolamine(DMEA)enhanced not only the regenerability of the A/D NAA but also the CO_(2)absorption ***,the CO_(2)absorption loading and cyclic loading were increased by about 12.7%and 15.5%-22.7%,*** TA-enhanced CO_(2)capture mechanism was comprehensively explored via nuclear magnetic resonance technique and quantum chemical *** CO_(2)absorption,the TA acted as an ultimate proton acceptor for AEEA-zwitterion and enabled more AEEA to form carbamate species(AEEACOO-)to store CO_(2),thus enhancing CO_(2)*** CO_(2)desorption,the TA first provided protons directly to AEEACOO-as a proton donor;moreover,it functioned as a proton carrier and facilitated the low-energy step-wise proton transfer from protonated AEEA to AEEACOO-.Consequently,the presence of TA made it easier for AEEACOO-to obtain protons to decompose,resulting in enhanced CO_(2)*** a word,introducing the TA as a proton-transfer mediator into the A/D NAA enhanced both the CO_(2)absorption performance and the regenerability,which was an efficient way to“kill two birds with one stone”.

关键词： Carbon dioxide capture Non-aqueous absorbent Tertiary amine Proton-transfer mediator Enhanced mechanism

Modified artificial neural network model with an explicit expression to describe flow behavior and processing maps of Ti2AlNb-based superalloy

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Journal of Iron and Steel Research International 2021年第11期28卷 1451-1462页

作者： Yan-qi Fu qing Zhao Man-qian lv Zhen-shan Cui School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Institute of Forming Technology and Equipment Shanghai Jiao Tong UniversityShanghai 200030China

The elevated-temperature deformation behavior of Ti2AlNb superalloy was observed by isothermal compression experiments in a wide range of temperatures(950–1200°C)and strain rates(0.001–10 s^(-1)).The flow behavior is nonlinear,strongly coupled,and *** constitutive models,namely the double multivariate nonlinear regression model,artificial neural network model,and modified artificial neural network model with an explicit expression,were applied to describe the Ti2AlNb superalloy plastic deformation *** comparative predictability of those constitutive models was further evaluated by considering the correlation coefficient and average absolute relative *** comparative results show that the modified artificial network model can describe the flow stress of Ti2AlNb superalloy more accurately than the other developed constitutive *** explicit expression obtained from the modified artificial neural network model can be directly used for finite element *** modified artificial neural network model solves the problems that the double multivariate nonlinear regression model cannot describe the nonlinear,strongly coupled,and multivariable flow behavior of Ti2AlNb superalloy accurately,and the artificial neural network model cannot be embedded into the finite element software ***,the modified artificial neural network model is mainly dependent on the quantity of high-quality experimental data and characteristic variables,and the modified artificial neural network model has not physical ***,the processing maps were applied to obtain the optimum processing parameters.

关键词： Modified artificial neural network model Ti2AlNb superalloy Double multivariate nonlinear regression model Explicit expression Processing map

Research progress on permeability improvement mechanisms and technologies of coalbed deep-hole cumulative blasting

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International Journal of Coal Science & Technology 2020年第2期7卷 329-336页

作者： Deyong Guo Pengfei lv Jiechao Zhao chao Zhang School of Emergency Management and Safety Engineering China University of Mining and TechnologyBeijingBeijing100083China Safety Engineering College Beijing Institute of Petrochemical TechnologyBeijing102617China

Coalbed gas extraction is an important means of exploiting and utilizing gas resources,as well as a means of preventing coal mine *** view of the low gas extraction rate from coalbeds with high gas content and low permeability,a method of improving permeability through deep-hole cumulative blasting is applied to develop initial directional fractures using a jet *** the action of the blasting stress wave and detonation gas wedge,the fractures extend over a large range within the coal,thereby improving coalbed *** study focuses on the criteria of cumulative blasting-induced coalbed fracturing based on a literature review of the penetration effect of cumulative *** this basis,we summarize the coal fracturing zone,crack extension process,and the key technologies of charging and hole sealing for cumulative *** addition,the latest research progress in the optimization of field test drilling and blasting parameters for cumulative blasting is *** findings indicate that the permeability improvement mechanism of cumulative blasting could be further enhanced,and the technology and technical equipment are in urgent need of ***,development trends in the cumulative blasting permeability improvement technique are identified.

关键词： Cumulative blasting Fracturing mechanism Coalbed permeability improvement Permeability improvement technology Gas extraction

Microstructure and Corrosion Resistance of Plasma Electrolytic Oxidized Recycled Mg Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第6期35卷 961-974页

作者： You lv chao Zhang Yupeng Zhang qishi Wang Xinxin Zhang Zehua Dong Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Hubei Engineering Research Centre for Biomaterials and Medical Protective Materials Huazhong University of Science and TechnologyWuhan 430074China China Railway Major Bridge Engineering Group Material and Equipment Supply Co.Ltd.Wuhan 430000China

The wide application of Mg is hindered by its low corrosion resistance,especially for recycled *** this work,a novel plasma electrolytic oxidation(PEO)process was conducted on a recycled Mg alloy with a high content of Al(~2.3 wt%),which results in a polycrystalline PEO *** PEO coating displays a three-layered structure with a uniform elemental *** the outer layer decorated by channels of micrometre scales,the middle layer mainly contains submicronsized pores associated with plasma discharges,whereas the fine pores originated from oxygen evolution were detected in the inner *** electrochemical measurements,hydrogen evolution tests and salt spray tests were conducted,indicating the superior corrosion resistance of PEO-coated recycled Mg ***,the purposed PEO method could dramatically enhance the corrosion resistance of recycled Mg,which may broaden its application in the future.

关键词： Recycled Mg Plasma electrolytic oxidation Corrosion resistance Layered structure

Insight into the large electro-strain in bismuth sodium titanate-based relaxor ferroelectrics:From fundamentals to regulation methods

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Journal of Materials Science & Technology 2023年第19期150卷 27-48页

作者： Xiaojun Wu Lanji Wen chao Wu Xiang lv Jie Yin Jiagang Wu College of Materials Science and Engineering Sichuan University610064PR China

Due to the demand for environmental protection,developing eco-friendly piezoelectric applica-tions/materials is an inevitable *** market share of lead-free materials is growing steadily every *** typical lead-free systems,Bi_(0.5)Na_(0.5)TiO_(3)(BNT)has attracted wide attention due to its supe-rior strain property(e.g.,dynamic piezoelectric coefficient d33*of most modified-BNT ceramics exceeds 600 pm/V,which is higher than commercial soft PZT ceramics PIC151).The excellent strain performance in BNT-based materials is thought to arise from the relaxor-ferroelectric transition,and currently,the mainstream strain regulation method is chemical *** far,amounts of effective dopants have been investigated,while the intrinsic strain regulation mechanism is still ambiguous(e.g.,how do dopants work?).Therefore,we review the intrinsic strain regulation mechanism,and strain origination and reg-ulation methods are also investigated to comprehend the regulation ***,the strain origination and regulation mechanism are investigated from different dimensions(e.g.,macro perspective and micro perspective),which is vacant in previous *** the macro view,the particular tai-lored relaxor-ferroelectric crossover is the critical key for the giant electro-strain,while from the micro view,the electro-strain is dominated by the cracked ferroelectric order and relaxor-ferroelectric transi-tion,resulting from the broken Bi-O bonds due to the local field *** the strain origination and regulation mechanism of BNT-based ceramics is of great importance to exclude the blind researching mode and rationally design the experimental scheme.

关键词： Strain origin Bi_(0.5)Na_(0.5)TiO_(3)(BNT) Strain regulation

A Review on Recent Development of Cooling Technologies for Photovoltaic Modules

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Journal of Thermal Science 2020年第6期29卷 1410-1430页

作者： ZHANG Chunxiao SHEN chao WEI Shen WANG Yuan lv Guoquan SUN Cheng Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology Ministry of Industry and Information TechnologySchool of ArchitectureHarbin Institute of TechnologyHarbin 150090China The Bartlett School of Construction and Project Management University College London(UCL)London WC1E 7HBUK

When converting solar energy to electricity,a big proportion of energy is not converted for electricity but for heating PV cells,resulting in increased cell temperature and reduced electrical *** cooling technologies have been developed and used for PV modules to lower cell temperature and boost electric energy ***,little crucial review work was proposed to comment cooling technologies for PV ***,this paper has provided a thorough review of the up-to-date development of existing cooling technologies for PV modules,and given appropriate comments,comparisons and *** to the ways or principles of cooling,existing cooling technologies have been classified as fluid medium cooling(air cooling,water cooling and nanofluids cooling),optimizing structural configuration cooling and phase change materials *** influential factors and sub-methods were collected from the review work,and their contributions and impact have been discussed to guide future *** most cooling technologies reviewed in this paper are matured,there are still problems need to be solved,such as the choice of cooling fluid and its usability for specific regions,the fouling accumulation and cleaning of enhanced heat exchangers with complex structures,the balance between cooling cost and net efficiency of PV modules,the cooling of circulating water in tropical areas and the freezing of circulating water in cold *** be advocated,due to efficient heat transfer and spectral filter characters,nanofluids can promote the effective matching of solar energy at both spectral and spatial scales to achieve orderly energy utilization.

关键词： solar energy PV modules cooling technologies nanoparticles phase change materials

Ferrosilicon alloy granules prepared through centrifugal granulation process

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Journal of Iron and Steel Research International 2020年第11期27卷 1247-1258页

作者： Wen-chao He Xue-wei lv Zhi-ming Yan Gang-qiang Fan Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China

A novel granulation process that involved the use of a rotary multi-nozzles cup atomizer and water cooling was proposed for ferroalloy *** effects of rotating speed and nozzle diameter on the properties of FeSi75 alloy(containing 75 wt.%Si)granules were *** indicated that median granule diameter decreased as rotating speed in creased,and initially increased and then decreased as nozzle diameter in *** optimal conditi ons for the gra nulation of FeSi75 alloy were a rotating speed of 150 r/min and nozzle diameter of 10 or 12 *** phase composition,micromorphology,and elemental distribution of the FeSi75 alloy granules were also studied by X-ray diffraction,scanning electron microscopy,and energy-dispersive X-ray *** order to provide guidance for the layout and water depth of the tank,the solidification behavior of ferrosilicon alloy droplet was numerically studied.A simplified model was established to elucidate the traveling trajectory and heat transfer of alloy droplet in air and cooling water during the atomization *** solidification time of droplet with different thicknesses of solidification layer increased with the in crease in alloy droplet diameter.

关键词： FeSi75 alloy Rotary multi-nozzles cup atomizer Size distribution Microstructural analysis Solidification behavior