检索结果-南通市图书馆

PREPARATION AND XRD STUDy OF LITHIUM DEFICIENT LiB COMPOUND

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 667-671页

作者： z.J.Liu B.y.Huang z.y.Li StateKeyLaboratoryforPowderMetallurgy CentralSouthUniversityChangsha410083China

The LiB compounds in lithium deficient state were prepared by three methods and its crystal structure was investigated by using XRD. It is found that the lattice constant c of the compound will increase step by step with decreasing Li content from 0.2796nm of the normal LiB to 0.2886, 0.2981 and 0.3118nm of the lithium deficient LiB. The change of the lattice constant is reversible.

关键词： LiB compound crystal structure electrode materials X-ray diffraction

Dispersion and Damage of Carbon Nanotubes in Carbon Nanotube/7055Al Composites During High-Energy Ball Milling Process

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2021年第2期34卷 196-204页

作者： S.Bi B.L.Xiao z.H.Ji B.S.Liu z.y.Liu z.y.Ma Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Material Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China AVIC Manufacturing Technology Institute Beijing 100024China

High-energy ball milling(HEBM)combined with powder metallurgy route was used to fabricate carbon nanotube(CNT)reinforced 7055 Al *** powder morphology evolution processes(HEBM-1 and HEBM-2)were designed to investigate the dispersion and damage of CNTs during HEBM ***-1 evolution process involved powder fl attening,cold-welding and fracture,while HEBM-2 evolution process consisted of powder fl attening and *** HEBM-1,the repetitive fracture and cold-welding process was effective for dispersing ***,the powder fl attening process in HEBM-2 was unsuccessful in dispersing CNTs due to two reasons:(1)the thickness of fl aky Al powders exceeded the critical value,and(2)the clustered CNTs embedded in fl aky Al powders could not be *** of the broadening of D band and the appearance of a new defect-related D’band,product of I D/I G and full width half maximum of D band,rather than I D/I G,was used to evaluate the actual damage of *** indicates that the damage of CNTs was severe in powder fl attening and fracture stages,while the damage of CNTs was small in powder cold-welding stage.

关键词： Metal matrix composites Carbon nanotubes Powder evolution Dispersion and damage Powder metallurgy

Giant magnetocaloric effect in the Gd_5 Ge_(2.025)Si_(1.925)In_(0.05) compound

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2010年第3期19卷 517-522页

作者： E.yzak I.Dincer y.Elerman Department of Engineering Physics Faculty of EngineeringAnkara University06100 BesevlerAnkaraTurkey

The magnetocaloric properties of the GdsGe2.025Si1.925In0.05 compound have been studied by x-ray diffraction, magnetic and heat capacity measurements. Powder x-ray diffraction measurement shows that the compound has a dominant phase of monoclinic Cd5Ge2Si2-type structure and a small quantity of Gds（Ge,Si）3-type phase at room temperature. At about 270 K, this compound shows a first order phase transition. The isothermal magnetic entropy change （△SM） is calculated from the temperature and magnetic field dependences of the magnetization and the temperature dependence of MCE in terms of adiabatic temperature change （△Tad） is calculated from the isothermal magnetic entropy change and the temperature variation in zero-field heat-capacity data. The maximum △SM is -13.6 J·kg^-1.K^- 1 and maximum ATad is 13 K for the magnetic field change of 0 5 T. The Debye temperature （θD） of this compound is 149 K and the value of DOS at the Fermi level is 1.6 states/*** from the low temperature zero-field heat-capacity data. A considerable isothermal magnetic entropy change and adiabatic temperature change under a field change of 0-5 T jointly make the Gd5Ge2.025Si1.925In0.05 compound an attractive candidate for a magnetic refrigerant.

关键词： magnetic properties magnetocaloric effect isothermal magnetic entropy change adia-batic temperature change

Analysis of Contact Melting Driven by Surface Heat Flux Around a Cylinder

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2008年第1期17卷 64-68页

作者： y.S.zhao W.z.Chen F.R.Sun z.y.Chen Faculty of Thermal Engineering College of Power and ShippingNaval University of EngineeringWuhan 430033China Faculty of Thermal Engineering College of Power and ShippingNaval University of EngineeringWuhan 430033China Professor

The contact melting of phase change material around a moving horizontal cylindrical heat source, which descended under its own weight, is investigated in this article. A melting model under constant surface heat flux is established. The analytical results for thickness and pressure distributions inside melt layer and steady melting velocity are obtained by using contact melting theory. The melting law is discussed, and compared with that of contact melting driven by temperature difference. It is found that quasi-steady melting velocity is determined by heat flux of heat source, and the variation of heat source density has less effect on melting velocity.

关键词： Contact melting horizontal cylinder phase change phenomena

Construction of Non-Equilibrium Gas Distribution Functions through Expansions in Peculiar Velocity Space

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2023年第6期15卷 1456-1472页

作者： z.y.yuan z.Chen C.Shu y.y.Liu z.L.zhang School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjingJiangsu 210094China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering National University of Singapore10 Kent Ridge Crescent119260Singapore

Gas distribution function plays a crucial role in the description of gas flows at the mesoscopic *** the presence of non-equilibrium flow,the distribution function loses its rotational symmetricity,making the mathematical derivation *** both the Chapman-Enskog expansion and the Hermite polynomial expansion(Grad’s method),we observe that the non-equilibrium effect is closely related to the peculiar velocity space(C).Based on this recognition,we propose a new methodology to construct the non-equilibrium distribution function from the perspective of polynomial expansion in the peculiar velocity space of *** coefficients involved in the non-equilibrium distribution function can be exactly determined by the compatibility conditions and the moment *** new framework allows constructing non-equilibrium distribution functions at any order of truncation,and the ones at the third and the fourth order have been presented in this paper for illustration *** validations demonstrate that the new method is more accurate than the Grad’s method at the same truncation error for describing non-equilibrium ***-dimensional benchmark tests are performed to shed light on the applicability of the new method to practical engineering problems.

关键词： Non-equilibrium gas distribution function peculiar velocity space complete poly-nomial expansion

Efect of Nanometer WC Coating on Thermal Conductivity of Diamond/6061 Composites

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 118-126页

作者： z.y.Dong D.Wang W.G.Wang B.L.Xiao z.y.Ma Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Liaoning Shihua University Fushun 113001China

Diamond has poor interface tolerance with *** enhance interface bonding,in this study,tungsten carbide(WC)nanocoatings on the surface of diamond particles were prepared using sol–gel and in-situ reaction ***_(3) sol–gel with two concentrations,0.2 mol/L,and 0.5 mol/L,was,respectively,coated on diamond particles,then sintered at 1250℃for 2 h to produce WC *** concentration of 0.2 mol/L WO_(3) sol–gel was not enough to cover the surface of the diamond completely,while 0.5 mol/L WO_(3) sol–gel could fully cover ***,WO_(3) was preferentially deposited on{100}planes of the ***_(3) converted to WC in-situ nanocoatings after sintering due to the in-situ reaction of WO_(3) and *** diamond-reinforced Al composites with and without WC coating were fabricated by powder *** diamond/Al composite without coating has a thermal conductivity of 584.7 W/mK,while the composite with a coating formed by 0.2 mol/L and 0.5 mol/L WO_(3) sol–gel showed thermal conductivities of 626.1 W/mK and 584.2 W/mK,*** moderate thickness of nanocoatings formed by 0.2 mol/L WO_(3) sol–gel could enhance interface bonding,therefore improving thermal *** nanocoating produced by 0.5 mol/L WO_(3) sol–gel cracked during the fabrication of the composite,leading to Al12W formation and a decrease in thermal conductivity.

关键词： Diamond Al matrix composite Nanometer coating WC Thermal conductivity

Numerical Modeling and Analysis of Grooved Surface Applied to Film Cooling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2011年第4期8卷 464-473页

作者： L. Guo z. C. Liu y. y. yan z. W. Han Faculty of Engineering University of Nottingham Nottingham NG7 2RD UK Department of Internal Combustion Engine Jilin University Changchun 130022 P. R. China Key Laboratory of Bionic Engineering （Ministry of Education China） Jilin University Changchun 130022 P. R. China

In order to improve the efficiency of film cooling, numerical investigation was carried out to study the effects of different film-cooled plates on surface heat transfer. Both grooved and non-grooved surfaces were concerned. The modeling was per- formed using Fluent software with the adoption of Shear-Stress Transport （SST） k-ωmodel as the turbulence closure. The coolant was supplied by a single film cooling hole with an inclination angle of 30°. The Mach numbers for the coolant flow and the mainstream flow were fixed at 0 and 0.6, respectively. At three blowing ratios of 0.5, 1.0 and 1.5, the aerodynamic behaviour of the mixing process as well as the heat transfer performance of the film cooling were presented. The numerical results were validated using experimental data extracted from a benchmark test. Good agreements between numerical results and the ex- perimental data were observed. For the film cooling efficiency, it shows that both local and laterally averaged cooling effectiveness can be improved by the non-smooth surface at different blowing ratios. Using the grooved surface, the turbulence intensity upon the plate can be reduced notably, and the mixing between the two flows is weakened due to the reduced turbu lence level. The results indicate that the cooling effectiveness of film cooling can be enhanced by applying the grooved surface.

关键词： film cooling non-smooth surface cooling effectiveness grooved structure blowing ratio

Shape Memory Alloy-Reinforced Metal-Matrix Composites:A Review

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 739-761页

作者： D.R.Ni z.y.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

Metal-matrix composites reinforced with shape memory alloys （SMA, including long fiber, short fiber, and particle） are ＂intelligent materials＂ with many special physical and mechanical properties, such as high damping property, high tensile strength, and fatigue resistance. In this review article, the fabrication method, microstructure, interface reaction, modeling, and physical and mechanical properties of the composites are addressed. Particular emphasis has been given to （a） fabrication and microstructure of aluminum matrix composites reinforced with SMAs, and （b） shape memory effect on the physical and mechanical properties of the composites. While the bulk of the information is related to aluminum matrix composites, important results are now available for other metal-matrix composites.

关键词： Metal-matrix composites Shape memory alloy Fabrication method Microstructure Interface reaction Mechanical properties

Simultaneous characterization of multiple properties of solid and liquid phases in crystallization processes using NIR

在线全文

学校读者我要写书评

暂无评论

Particuology 2011年第6期9卷 589-597页

作者： Chao y. Ma Xue z. Wang Institute of Particle Science and Engineering School of Process Environmental and Materials Engineering University of Leeds Leeds LS2 9JT UK

Near infrared spectroscopy （NIR） is now probably the most popular process analytical technology （PAT） for pharmaceutical and some other industries. However, unlike mid-IR, NIR is known to have difficulties in monitoring crystallization or precipitation processes because the existence of solids could cause distortion of the spectra. This phenomenon, seen as unfavorable previously, is however an indication that NIR spectra contain rich information about both solids and liquids, giving the possibility of using the same instrument for multiple property characterization. In this study, transflectance NIR calibration data was obtained using solutions and slurries of varied solution concentration, particle size, solid concentration and temperature. The data was used to build calibration models for prediction of the multiple properties of both phases. Predictive models were developed for this challenging application using an approach that combines genetic algorithm （GA） and support vector machine （SVM）. GA is used for wavelength selection and SVM for mode building. The new GA-SVM approach is shown to outperform other methods including GA-PLS （partial least squares） and traditional SVM. NIR is thus successfully applied to monitoring seeded and unseeded cooling crystallization processes of L-glutamic acid.

关键词： Process analytical technology Near infrared spectroscopy Support vector machine Genetic algorithm Wavelength selection Cooling crystallization