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Fluorescent SiC and its application to white light-emitting diodes

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Journal of Semiconductors 2011年第1期32卷 24-26页

作者： Satoshi Kamiyama Motoaki Iwaya Tetsuya Takeuchi Isamu Akasaki Mikael Syvjrvi Rositza Yakimova Department of Materials Science and Engineering meijo university Department of Physics Chemistry and Biology Linkping University

Fluorescent-SiC （f-SiC）, which contains donor and acceptor impurities with optimum concentrations, has high conversion efficiency from NUV to visible light caused by donor-acceptor-pair （DAP） recombination. This material can be used as a substrate for a near UVlight-emitting diode （LED） stack, and leads to monolithic white LED device with suitable spectral property for general lighting applications. In this paper, we describe basic technologies of the white LED, such as optical properties of f-SiC substrate, and epitaxial growth of NUV stack on the f-SiC substrate.

关键词： white LED phosphor SiC donor-acceptor-pair GaN general lighting

Bending behaviour of lightweight aggregate concrete-filled steel tube spatial truss beam

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Journal of Central South university 2016年第8期23卷 2110-2117页

作者：傅中秋吉伯海朱伟葛汉彬 College of Civil and Transportation Engineering Hohai University Department of Civil Engineering Meijo University

A lightweight aggregate concrete-filled steel tube(LACFST) spatial truss beam was tested under bending load. The performance was studied by the analysis of the beam deflection and strains in its chords and webs. According to the test results, several assumptions were made to deduce the bearing capacity calculation method based on the force balance of the whole section. An optimal dimension relationship for the truss beam chords was proposed and verified by finite element analysis. Results show that the LACFST spatial truss beam failed after excessive deflection. The strain distribution agreed with Bernoulli-Euler theoretical prediction. The truss beam flexural bearing capacity calculation results matched test evidence with only a 3% difference between the two. Finite element analyses with different chord dimensions show that the ultimate bearing capacity increases as the chord dimensions increase when the chords have a diameter smaller than optimal one; otherwise, it remains almost unchanged as the chord dimensions increase.

关键词：轻集料混凝土桁架梁空间钢管弯曲承载力计算方法有限元分析尺寸关系

A Position and Torque Switching Control Method for Robot Collision Safety

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International Journal of Automation and computing 2018年第2期15卷 156-168页

作者： Zhi-Jing Li Hai-Bin Wu Jian-Ming Yang Ming-Hao Wang Jin-Hua Ye School of Mechanical Engineering and Automation Fuzhou University Department of Mechanical System Meijo University

With the increasing number of human-robot interaction applications, robot control characteristics and their effects on safety as well as performance should be taken account into the robot control system. In this paper, a position and torque switching con- trol method was proposed to improve the robot safety and performance, when robots and humans work in the same space. The switch- ing control method includes two modes, the position control mode using a proportion-integral （PI） algorithm, and the torque control mode using sliding mode control （SMC） algorithm for eliminating swing. Under the normal condition, the robot works in position con- trol mode for trajectory tracking with quick response. Once the robot and human collide, the robot will switch to torque control mode immediately, and the impact force will be restricted within a safe range. When the robot and human detach, the robot will resume to po- sition control mode automatically. Moreover, for a better performance, the joint torque is detected fl＇om direct-current （DC） motor＇s cur- rent rather than the torque sensor. The experiment results show that the proposed approach is effective and feasible.

关键词： Human-robot interaction position control torque control switching control robot collision safety.

Experimental Study on Vortex Growth during the Early Development of Rotating Disks

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World Journal of Mechanics 2022年第3期12卷 41-50页

作者： Hiroyuki Furukawa Takeomi Yamazaki Department of Mechanical Engineering Meijo University Nagoya Japan

In previous studies, the effects of radial clearance on the flow of a rotating disk in a cylindrical vessel have been investigated by using rotating disks of different shapes. As a result, different flow phases were observed in each disk due to the difference in disk dimensions. In this study, we focus on the end-face effect and conduct experiments to visualize the vortex growth process and elucidate the generation mechanism of the vortex structure. From the experiment results, at Re = 4000, 7000, and 9000, four types of vortex flow modes appeared in the vortex development process. However, at Re = 4000, only regular 2-cells and regular 4-cells appeared, and at Re = 9000, only mutated 2-cells and mutated 3-cells appeared. In addition, it was found that only one type appeared depending on the rotational ascent time ts. When Re = 4000, the rotational ascent time ts = 0, 2, 7, and 8 was stable at regular 4-cells, while the others were finally stable in regular 2-cells. This study revealed the influence of the acceleration of the rotating disk on the non-unique flows in the cylindrical casing.

关键词： Rotating Disk Experimental Study Flow Instability Non-Uniqueness

Establishment of Particular Methods in Casting Simulation

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Journal of Shanghai Jiaotong university(Science) 2012年第4期17卷 475-478页

作者：陈萌杨剑鸣杨弋涛 School of Materials Science&Engineering Shanghai University Department of Mechanical Engineering Meijo University

Casting simulation tool ADSTEFAN is useful to design casting technology of complicated iron castings.Based on the function of solidification analysis,special methods were taken to carry out the prediction and optimization of shake-out timing for large sized iron castings.It has been proved that these analyses are effective to iron casting production.During the research of cast iron semi-solid process,to predict and control the influence of inclined cooling plate on flow and heat transmission of molten iron,the basis of analysis model has been built in this study.Flow field simulation considering temperature field was carried out for further research and satisfied with the practical production.

关键词： cast iron shake-out timing cooling plate simulation

Long-Term Effect of TMD on Vibration Control of An MDOF Offshore Fixed Platform

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China Ocean Engineering 2003年第4期18卷 481-494页

作者：石湘 Tetsuya MATSUI WU Minger Graduate School of Environmental Studies Nagoya University Nagoya 464-8603 Japan Department of Architecture Meijo University Nagoya 468-8503 Japan

A three-dimensional fixed offshore platform in deep water modeled by the finite element method is studied in this paper. Analysis of the dynamic response of the MDOF structure is realized taking the non-linearity of the wave drag force and the wave-structure interaction into account. The structural response statistics, which have Gaussian distributions, are used to evaluate the vibration effect of the structure without TMD and with TMD. And an optimal method to design TMD controlling the first mode of the multi-mode structure is proposed. Moreover, the probabilities of occurrence of sea states at the platform site are considered for prediction of the long-term effect of a TMD. Simulation results demonstrate that the long-term effect of a well-designed TMD is good and the practical use is possible due to the good stability of its optimal parameters under different sea states.

关键词： offshore fixed platform vibration control tuned mass damper multi degree of freedom optimal design

Parametric study on damage control design of SMA dampers in frame-typed steel piers

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Frontiers of Structural and Civil Engineering 2009年第4期3卷 384-394页

作者： Xiaoqun LUO Hanbin GE Tsutomu USAMI Advanced Research Center for Seismic Experiments and Computations Meijo UniversityNagoya 468-8502Japan Department of Building Engineering Tongji UniversityShanghai 200092China Department of Civil Engineering Meijo UniversityNagoya 468-8502Japan

This paper focuses on damage control design of SMA dampers in steel frame piers.A parametric study based on time history analyses is carried out on frametyped bridge piers with axial-type SMA damping device.The parameters examined are design parameters of strength ratioαF and stiffness ratioαK.Seismic performance indexes on displacement and strain are investigated under three JRA recommended Level 2 Ground TypeПstrong earthquake motions.Design recommendations are suggested following the results of the parametric study.

关键词： damage control design shape memory alloy parameter study displacement-based verification strainbased verification time history analysis

Fabrication of Aluminum/Single-Walled Carbon Nanotube Oxidation Films through CNT-Added Surface Treatment

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Journal of Surface Engineered Materials and Advanced Technology 2022年第1期12卷 1-13页

作者： Sangjae Kim Emi Matsuyama Hideharu Tajima Rikuma Miyake Takahiro Maruyama Research & Development Center Yamaichi Special Steel Nagoya Aichi Japan Department of Applied Physics Nagoya Institute of Technology Nagoya Aichi Japan Department of Applied Chemistry Meijo University Nagoya Aichi Japan Nanomaterial Research Center Meijo University Nagoya Aichi Japan

CNT-added surface treatment (CAST) is a newly developed technology that incorporates single-walled carbon nanotubes (SWCNTs) into a metal surface through alternate current electrolysis using a dispersion of SWCNTs in an alkaline aqueous solution. We apply this method to Al-plates and characterize their surface morphology and components through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. After CAST processing, protrusion structures of Al-oxide containing SWCNTs are formed on the surface of the Al-plate, and the surface morphology differs significantly from that of the surface of Al films treated through conventional anodic oxidation. The height and spacing of the protrusion structures formed on the surface of the CAST-treated Al-plates are 100 - 200 nm and 50 - 100 nm, respectively. In addition, we investigate the formation mechanism of the protrusion structure by applying a DC voltage between the working electrode (Al-plate) and a counter electrode immersed in a dispersion of SWCNTs in an alkaline aqueous solution. Comparing the Al-plate surface after treatment under both current directions, we propose a model for the formation process of protrusion structures containing SWCNTs based on catalyst surface etching.

关键词： SWCNT Anodic Oxidation Anodic Aluminum Oxide

New role of α phase in the fracture behavior and fracture toughness of a β-type bio-titanium alloy

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International Journal of Minerals,Metallurgy and Materials 2023年第9期30卷 1756-1763页

作者： Ran Wang Xiu Song Lei Wang Yang Liu Mitsuo Niinomi Deliang Zhang Jun Cheng Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education)School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Institute for Materials Research Tohoku University2-1-1 KatahiraAoba-kuSendai 980-8577Japan meijo university 1-501 ShiogamaguchiTempaku-kuNagoya 468-8502Japan Nagoya university Furo-choChikusa-kuNagoya 464-8601Japan Shaanxi Key Laboratory of Biomedical Metal Materials Northwest Institute for Nonferrous Metal ResearchXi’an 710016China

The role of α precipitates formed during aging in the fracture toughness and fracture behavior of β-type bio-titanium alloy Ti–29Nb–13Ta–4.6Zr(TNTZ) was studied. Results showed that the fracture toughness of the TNTZ alloy aged at 723 K decreases to the minimum of 72.07–73.19 kJ·m^(-2)when the aging time is extended to 4–8 h and then gradually increases and reaches 144.89 kJ·m^(-2)after 72 h. The decrease in fracture toughness within the aging time of 4–8 h is caused by the large stress concentration at the tip of acicular α precipitates with a high aspect ratio and the preferential crack propagation along the inhomogeneous acicular α precipitates distributed in “V-shape” and “nearly perpendicular shape”. When the aging time is extended to 8–72 h, the precrack tip is uniformly blunted, and the crack is effectively deflected by α precipitates with multi long axis directions, more high homogeneity, low aspect ratio, and large number density. Analysis of the effect of αprecipitates on the fracture behavior suggested that the number of long axis directions of α precipitates is the key controlling factor for the fracture behavior and fracture toughness of the TNTZ alloy aged for different times.

关键词： fracture toughness Ti-29Nb-13Ta-4.6Zr alloy agedαphase crack tip blunting