检索结果-南通市图书馆

Precipitation Characteristics and Mechanism of Vanadium Carbides in a V-Microalloyed Medium-Carbon Steel

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) 2018年第11期31卷 1197-1206页

作者： Xiao-Lin Pan minoru Umemoto School of Metallurgy Northeastern University Department of Mechanical Engineering Toyohashi University of Technology

The precipitation characteristics and mechanism of vanadium carbides during isothermal transformation at 650℃ in aV-microalloyed medium-carbon steel were investigated through scanning electron microscopy and transmission electronmicroscopy as well as dilatometry test. Five morphologies of vanadium carbides were found to precipitate at differentnucleation sites during the transformation. Two kinds of interphase precipitation form simultaneously in both pro-eutectoidand pearlitic ferrites. The linear arrays of fine interphase precipitates are parallel to the γ/α interface, and the fine needles ofinterphase precipitates are perpendicular to the 7/ct interface. The vanadium carbides of long or short fibers, coarse particlesand fine particles form in both pro-eutectoid and pearlitic ferrites, displaying different precipitation distributions andorientation relationships with ferrite. The precipitation mechanisms of vanadium carbide precipitates with different modeswere proposed, and the precipitation sequence of various vanadium carbide precipitates was finally ascertained.

关键词： Microalloyed steels Carbide precipitation Isothermal transformation Precipitation sequence Orientation relationship

Experimental and Numerical Study of Twin Underexpanded Impinging Jets

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2003年第3期12卷 255-259页

作者： minoru Yaga minoru Okano Masumi Tamashiro Kenyu Oyakawa Department of Mechanical Systems Engineering Faculty of Engineering University of the RyukyusSenbaru 1 Okinawa 903-0213 JAPANDepartment of Mechanical Systems Engineering Faculty of Engineering University of the RyukyusSenbaru 1 Okinawa 903-0213 JAPANDepartment of Mechanical Systems Engineering Faculty of Engineering University of the RyukyusSenbaru 1 Okinawa 903-0213 JAPANDepartment of Mechanical Systems Engineering Faculty of Engineering University of the RyukyusSenbaru 1 Okinawa 903-0213 JAPAN

In this paper, the dual underexpanded impinging jets are experimentally and numerically studied. The experiments were performed by measuring the unsteady and averaged wall static pressures and by visnalizing density fields using schlieren method. Numerical calculations were also conducted by solving unsteady three dimensional compressible Navier-Stokes equations with Baldwin-Lomax turbulence model. The main parametm''s for the dual jets are the non-dimensional distance between the two nozzle centers H/D covering 1.5, 2.0, the nozzle to plate separation L/D 2.0, 3.0,4.0 and 5.0 and the pressure ratio defined by Po/Pb 1.0-6.0, where D is the diameter of each nozzle exit, Po the stagnation pressure and Pb the back pressure. It is found that the agreement between the experiments and the calculations is good. The fountain flow at the middle of the two jets is observed both in the experiments and the calculation. According to FFT analysis of the experiments for the twin jets,relatively low frequgncy (up to 5 kHz) is dominant for H/D =1.5, L/D =2.0 and pressure rafio po/Pb =3.0 and 5.0,which is confLrmed by the experiments.

关键词：可压缩流体力学冲击波碰撞射流 CFD 计算流体力学喷射流动实验研究数值分析

One-Dimensional Analysis of Supersonic Two-Stage HVOF Process

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2009年第4期18卷 332-337页

作者： Hiroshi KATANODA Junichi HAGI minoru FUKUHARA Dept.Mechanical Engineering Kagoshima University

The one-dimensional calculation of the gas/particle flows of a supersonic two-stage high-velocity oxy-fuel(HVOF) thermal spray process was performed. The internal gas flow was solved by numerically integrating theequations of the quasi-one-dimensional flow including the effects of pipe friction and heat transfer. As for the supersonicjet flow, semi-empirical equations were used to obtain the gas velocity and temperature along the centerline. The velocity and temperature of the particle were obtained by an one-way coupling method. The material ofthe spray particle selected in this study is ultra high molecular weight polyethylene (UHMWPE). The temperaturedistributions in the spherical UHMWPE particles of 50 and 150 m accelerated and heated by the supersonic gasflow was clarified.

关键词： Compressible Flow Supersonic Flow Two-Stage HVOF Thermal Spray One-Dimensional Analysis UHMWPE

Exact Bosonic Solutions of the Truncated Skyrme Model

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第6期27卷 35-36页

作者： SHI Chang-Guang HIRAYAMA minoru Department of Mathematics and Physics Shanghai University of Electric Power Shanghai 200090 Department of Physics University of Toyama Gofuku 3190 Toyama Japan

A model defined by half the Lagrangian （the highly nonlinear part） of the Skyrme model is investigated. Two classes of bosonic solutions are obtained. It is shown that, although the field configurations of these two... 详细信息

关键词： SKYRME model BOSONS LAGRANGE equations FIELD theory (Physics) MATHEMATICAL physics FORCE & energy

Experimental study of unsteady supersonic flow interacting with porous cavity and jets or rods

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 Thermal Science 2014年第2期23卷 153-159页

作者： Nao Kuniyoshi minoru Yaga Isao Teruya Masaaki Ishikawa Graduate schools of engineering and science University of the Ryukyus1 SenbaruNishiharaOkinawa903-0213Japan Department of Mechanical System Engineering University of the Ryukyus1 SenbaruNishiharaOkinawa903-0213Japan

In this study,an experiment was performed to clarify the flow field,in which the jets were normally injected into a main supersonic flow surrounded by a porous cavity,and this report figures out interaction between starting shock wave and porous *** the experiment,a porous cavity is attached to a main duct and jets and rods are inserted to the main duct on the porous *** reveal this flow field,the thermal tuft probe was adopted to experimentally investigate the flow in the *** the experiments,the effect of the porous cavity with jets or rods on the flow field is studied by means of visualization of schlieren method with a high speed camera and measurement of cavity flow with thermal tuft *** a results,frequency analysis of output of the thermal tuft probe revealed that some clear dominant frequencies were confirmed when the starting shock wave existed around the porous cavity in all cases of jets and rods ***,visualization of schlieren method with a high speed camera clarified that a starting shock wave had the same dominant frequencies as that of the flow fluctuation in the cavity only around the cavity.

关键词： Shock wave Compressible flow Porous cavity Unsteady flow direction

Fluid Flow and Infrared Image Analyses on Endwall Fitted with Short Rectangular Plate Fin

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2006年第2期15卷 145-151页

作者： Kenyu OYAKAWA Islam Md. DIDARUL minoru YAGA Dept. of Mechanical Systems Engineering University of the Ryukyus Okinawa Japan. Faculty of Engineering University of the Ryukyus Okinawa Japan.

An experimental investigation is carded out to study fluid flow and heat transfer characteristics on the endwall fitted with arrays （ 7 × 7 ） of short rectangular plate fins of different pattern （co-angular and zigzag） for different pitch ratio. Experiments were conducted in a rectangular duct of 50 mm height for an air flow of Reynolds number ranged from 18750 to 62500 based on the equivalent diameter and air velocity of the duct. Infrared image analysis technique was employed to make clear the characteristics of local heat transfer coefficients on fin base, endwall and overall surface. Flow pattern around the short rectangular plates were visualized by inducing fluorescent dye in a water channel and longitudinal vortices were observed. Increasing the distance between plates in flow direction causes heat transfer enhancement for co-angular pattern, while decreasing the distance causes heat transfer enhancement for zigzag pattern. Zigzag pattern with pitch ratio 2 is found to be more effective in heat transfer enhancement than any other cases investigated.

关键词： infrared image rectangular plate convection heat transfer flow visualization

Flow Characteristics of Rectangular Underexpanded Impinging Jets

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2006年第1期15卷 59-64,30页

作者： minoru YAGA Yoshio KINJO Masumi TAMASHIRO Kenyu OYAKAWA Dept. of Mechanical System Engineering University of the Ryukyus Okinawa 903-0213 Japan Mazda Motor Corporation Hiroshima 730-8670 Japan

In this paper, the flow fields of underexpanded impinging jet issued from rectangular nozzles of aspect ratio 1, 3 and 5 are numerically and experimentally studied. Two dimensional temperature and pressure distributions are measured by using infrared camera and the combination of a pressure scanning device and a stepping motor, respectively. The variation of the stagnation pressure on the impinging plate reveals that a hysteretic phenomenon exists during the increasing and decreasing of the pressure ratio for the aspect ratio of 3.0 and 5.0. It is also found that the nozzle of aspect ratio 1.0 caused the largest total pressure loss Pc /p0= 0.27 at the pressure ratio of Po /p0 = 6.5, where Pc is the stagnation center pressure on the wall, P0 the upstream stagnation pressure, Pb the ambient pressure. The other two nozzles showed that the pressure loss Pc / P0 =0.52 and 0.55 were achieved by the nozzles of the aspect ratio 3,0 and 5.0, respectively. The comparison between the calculations and experiments is fairly good, showing the three dimensional streamlines and structures of the shock waves in the jets. However, the hysteresis of the pressure variations observed in the experiments between the pressure ratio of 3.5 and 4.5 cannot be confirmed in the calculations.

关键词： compressible flow shock wave under-expanded rectangular impinging jet CFD.

Behavior of Shock Waves Formed by Unsteady Supersonic Jet Injected into Cell

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 50-55页

作者： minoru YAGA Hiroshi FUKUOKA Yasushi IWATA Toshio TAKIYA Depts.Mech.Systems Eng. Univ.of the RyukyusSenbaru 1NishiharaOkinawa903-0213 Professor Graduate student Faculty of Eng.Univ.of the RyukyusSenbaru 1NishiharaOkinawa903-0213 Nanoelectronics Research Institute AIST Tsukuba Central 2Tsukuba 305-8568 Hitachi Zosen Corporation 2-11 Funamachi2 chomeTaishou-kuOsaka 551-0022

The unsteady behavior of flow driven by a jet suddenly injected into a cell is numerically studied by solving the axisymmelric two-dimensional compressible Navier-Stokes equations. The system of the calculation is a model of the laser ablation of a certain duration followed by a discharging process through the exit hole at the down- stream end of the cell. In the calculations, the contour of the cell is changed while other parameters such as the Mach number of the jet, its duration, and the diameter of the cell exit are fixed. Monitoring the velocity at the exit hole is used to investigate the influence of the shape on the interaction between the shock wave and the jet. As the result, it was found that the velocity peak value and its arrival time at the downstream end of the cell exit are determined by the diameter of the cell.

关键词： Shock wave CFD supersonic flow unsteady jet velocity variation

Preparation of Lanthanum Nickel Oxide-Coated Ni Sheet Anodes and Their Application to Electrolytic Production of (CF_3)_3N in (CH_3)_4NF·4.0HF Melt

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第1期24卷 1-8页

作者： Yoshio Shodai minoru Inaba Kazuki Onoda Akimasa Tasaka Department of Molecular Science and Technology Faculty of Engineering Doshisha University Kyotanabe Kyoto 610-0321 Japan

A new process for electrolytic production of a perfluorinated compound, （CF3）3N, using lanthanum nickel oxide-coated Ni sheet anode in the （CH3）4NF· 4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone（PVP）. The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000℃, respectively. The anode performance in the （CH3）4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm^-2 in the （CH3）4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of （CF3）3N （21.4%） was obtained at 20 mA·cm^-2 in （CH3）4NF·4.0HF melt using the LaNiO3-coated Ni sheet.

关键词： electrolytic perfluorination lanthanum nickel oxide perfluorotrimethylamine rare earths