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Microstructure and Wear Behavior of Cermet/Iron Alloy Cladding Layers on A6061 Alloy Coated by Resistance Seam Welding Method

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Acta Metallurgica Sinica(English Letters) 2015年第4期28卷 414-423页

作者： Wen-Qin Wang Tomiko yamaguchi Kazumasa Nishio Faculty of Engineering Kyushu Institute of Technology Nishinippon Institute of Technology

Cermet/iron alloy cladding layers were coated on the surface of Al-Mg-Si alloy （A6061） plates by resistance seam welding method with tungsten carbide （WC） and high-carbon iron alloy （SHA） powders. The cladding layer consisted of WC reinforcement, SHA binder, A6061 and FeAl3. The effect of WC ratio （30 wt%, 50 wt% and 70 wt%） on the microstructure and wear behavior of the cladding layers was investigated in detail. Abrasive wear test was performed under two kinds of load condition by using a rubber wheel apparatus to evaluate wear resistance. The results showed that the wear resistance of the cladding layer was improved by 3.5-5 times than that of the substrate. At lower load, the wear resistances of the samples 30% and 70% WC were nearly the same, which suggested that FeAl3 played an important role in improvement of the wear resistance instead of WC. While at higher load, the amount of WC determined the wear resistance of the cladding layer. Furthermore, wear behavior of these cladding layers was explained with reference to the observed microstructure of the worn surface.

关键词： Resistance seam welding A6061 WC Cladding layer Wear resistance

Real-time rendering of layered materials with anisotropic normal distributions

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Computational Visual Media 2020年第1期6卷 29-36页

作者： Tomoya yamaguchi Tatsuya Yatagawa Yusuke Tokuyoshi Shigeo Morishima Waseda University Tokyo155-8885Japan The University of Tokyo Tokyo153-8656Japan Intel Corporation CA95054USA

This paper proposes a lightweight bidirectional scattering distribution function(BSDF)model for layered materials with anisotropic reflection and refraction *** our method,each layer of the materials can be described by a microfacet BSDF using an anisotropic normal distribution function(NDF).Furthermore,the NDFs of layers can be defined on tangent vector fields,which differ from layer to *** method is based on a previous study in which isotropic BSDFs are approximated by projecting them onto base ***,the adequateness of this previous work has not been well investigated for anisotropic *** this paper,we demonstrate that the projection is also applicable to anisotropic BSDFs and that the BSDFs are approximated by elliptical distributions using covariance matrices.

关键词： layered materials microfacet BSDF reflection modeling real-time rendering

Hybrid image of three contents

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Visual Computing for Industry,Biomedicine,and Art 2020年第1期3卷 31-38页

作者： Peeraya Sripian Yasushi yamaguchi SIT Research Laboratory Shibaura Institute of TechnologyRoom#04R313-7-5 ToyosuKoto-kuTokyo 135-8548Japan The University of Tokyo Bldg.#15Room#505A3-8-1KomabaMeguro-kuTokyo 153-8902Japan

A hybrid image allows multiple image interpretations to be modulated by the viewing ***,it can be constructed by combining the low and high spatial frequencies of two different *** original hybrid image synthesis was limited to similar shapes of source images that were aligned in the edges,e.g.,faces with a different expression,to produce an effective double image *** our previous work,we proposed a noiseinserted method for synthesizing a hybrid image from dissimilar shape images or unaligned *** this work,we propose a novel method for adding an image to be seen from a middle viewing *** middlefrequency(MF)image is extracted by a special bandpass filter,which generates ringing while extracting only specified frequency *** this method,the middle frequency should be perceived as a meaningless pattern when viewed from a far distance and close up.A parameter tuning experiment was performed to determine the suitable cutoff frequencies for designing the filter for the MF *** found that ringings of a suitable size could be used to make the middle frequency less noticeable when seen from far away.

关键词： Hybrid image Contrast sensitivity Frequency filtering Scale-space

Improved image denoising via RAISR with fewer filters

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维普期刊数据库

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Computational Visual Media 2021年第4期7卷 499-511页

作者： Theingi Zin Yusuke Nakahara Takuro yamaguchi Masaaki Ikehara Department of Electronics and Electrical Engineering Keio UniversityYokohama-shi223-8522Japan

In recent years,accurate Gaussian noise removal has attracted considerable attention for mobile applications,as in smart *** conventional denoising methods have the potential ability to improve denoising performance with no additional ***,we propose a rapid post-processing method for Gaussian noise removal in this *** matching and 3D filtering and weighted nuclear norm minimization are utilized to suppress *** these nonlocal image denoising methods have quantitatively high performance,some fine image details are lacking due to the loss of high frequency *** tackle this problem,an improvement to the pioneering RAISR approach(rapid and accurate image super-resolution),is applied to rapidly post-process the denoised *** gives performance comparable to state-of-the-art super-resolution techniques at low computational cost,preserving important image structures *** modification is to reduce the hash classes for the patches extracted from the denoised image and the pixels from the ground truth to 18 filters by two improvements:geometric conversion and reduction of the strength *** addition,following RAISR,the census transform is exploited by blending the image processed by noise removal methods with the filtered one to achieve artifact-free *** results demonstrate that higher quality and more pleasant visual results can be achieved than by other methods,efficiently and with low memory requirements.

关键词： block matching and 3D filtering weighted nuclear norm minimization super-resolution geometric conversion census transform

Effects of Aspect Ratio in a Transonic Shock Tube Airfoil Flow

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Journal of Thermal Science 2012年第5期21卷 435-440页

作者： Masashi KASHITANI Keita MIURA Shinichiro NAKAO Yutaka yamaguchi Department of Aerospace Engineering National Defense Academy1-10-20 Hashirimizu Yokosuka 239-8686 JAPAN Department of Mechanical Engineering Nagasaki Institute of Applied Science 536 Aba-MachiNagasaki 851-0193 JAPAN

In the present study, the flow visualizations were performed around the NACA 0012 models which differ in aspect ratios. We discussed the effects of the aspect ratio in the test models. Additionally the unsteady, two-dimensional, compressible Euler equations were solved for the NACA 0012 airfoil. Experiments were performed utilizing the conventional gas driven shock tube as the intermittent transonic wind tunnel. The aspect ratios of the models are about 0.86 and 1.5, respectively. The Mach numbers M 2 are about 0.84. The Reynolds numbers of the present experimental conditions were constant that Re based on chord length is about 4.0×10 5 . The results are as follows: in different aspect ratios, the difference of the shock wave location is confirmed though the Mach number and Reynolds number are same. It indicates the different correction Mach number by the effects of the side wall boundary layer though the nominal Mach number measured the same value. Also, on the difference of shock wave location for the effects of the aspect ratio, the tend of CFD shows the qualitative agreement with the result of an experiment.

关键词： Shock tube Aerodynamics Transonic flows Aspect ratio Wind tunnel correction

Model predictive control for hybrid vehicle ecological driving using traffic signal and road slope information

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Control Theory and Technology 2015年第1期13卷 17-28页

作者： Kaijiang YU Junqi YANG Daisuke yamaguchi School of Electrical Engineering and Automation Henan Polytechnic University School of Information Science and Electrical Engineering Kyushu University

This paper presents development of a control system for ecological driving of a hybrid vehicle. Prediction using traffic signal and road slope information is considered to improve the fuel economy. It is assumed that the automobile receives traffic signal information from intelligent transportation systems （ITS）. Model predictive control is used to calculate optimal vehicle control inputs using traffic signal and road slope information. The performance of the proposed method was analyzed through computer simulation results. Both the fuel economy and the driving profile are optimized using the proposed approach. It was observed that fuel economy was improved compared with driving of a typical human driving model.

关键词： Ecological driving model predictive control intelligent transportation systems traffic signal optimal control

Possible Sources of Forecast Errors Generated by the Global/Regional Assimilation and Prediction System for Landfalling Tropical ***Ⅰ:Initial Uncertainties

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Advances in Atmospheric Sciences 2016年第7期33卷 841-851页

作者： Feifan ZHOU Munehiko yamaguchi Xiaohao QIN Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmowheric PhysicsChinese Academy of SciencesBeijing 100029 Meteorological Research Institute of the Japan Meteorological Agency Tsukuba 305-0052Japan State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029

This paper investigates the possible sources of errors associated with tropical cyclone （TC） tracks forecasted using the Global/Regional Assimilation and Prediction System （GRAPES）. The GRAPES forecasts were made for 16 landfaIling TCs in the western North Pacific basin during the 2008 and 2009 seasons, with a forecast length of 72 hours, and using the default initial conditions （＂initials＂, hereafter）, which are from the NCEP-FNL dataset, as well as ECMWF initials. The forecasts are compared with ECMWF forecasts. The results show that in most TCs, the GRAPES forecasts are improved when using the ECMWF initials compared with the default initials. Compared with the ECMWF initials, the default initials produce lower intensity TCs and a lower intensity subtropical high, but a higher intensity South Asia high and monsoon trough, as well as a higher temperature but lower specific humidity at the TC center. Replacement of the geopotential height and wind fields with the ECMWF initials in and around the TC center at the initial time was found to be the most efficient way to improve the forecasts. In addition, TCs that showed the greatest improvement in forecast accuracy usually had the largest initial uncertainties in TC intensity and were usually in the intensifying phase. The results demonstrate the importance of the initial intensity for TC track forecasts made using GRAPES, and indicate the model is better in describing the intensifying phase than the decaying phase of TCs. Finally, the limit of the improvement indicates that the model error associated with GRAPES forecasts may be the main cause of poor forecasts of landfalling TCs. Thus, further examinations of the model errors are required.

关键词： tropical cyclone track forecast error diagnosis Global/Regional Assimilation and Prediction System initialuncertainty

Reconstruction of power spectrum of primordial curvature perturbations on small scales from primordial black hole binaries scenario of LIGO/VIRGO detection

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Science China(Physics,Mechanics & Astronomy) 2023年第6期66卷 87-93页

作者： Xinpeng Wang Ying-li Zhang Rampei Kimura Masahide yamaguchi School of Physics Science and Engineering Tongji UniversityShanghai200092China Institute for Advanced Study of Tongji University Shanghai200092China Kavli Institute for the Physics and Mathematics of the Universe(WPI) Chiba277-8583Japan Center for Gravitation and Cosmology Yangzhou UniversityYangzhou225009China Waseda Institute for Advanced Study Waseda UniversityTokyo169-8050Japan Department of Physics Tokyo Institute of TechnologyTokyo152-8551Japan

As a candidate bound for the Binary Black Hole(BBH) merger events detected by LIGO/Virgo, Primordial Black Holes(PBHs)provide a useful tool to investigate the primordial curvature perturbations on small scales. Using the GWTC-1 to GWTC-3 catalogs, under the scenario that PBHs originate from large primordial curvature perturbations on small scales during infiationary epoch, we for the first time reconstruct the power spectrum of primordial curvature perturbations on small scales. It is found that the value of the amplitude of the primordial power spectrum is enhanced to O(10-2)on scales O(1) pc. This may imply the validity of PBH as a possible BBH merger candidate.

关键词： primordial black hole primordial curvature perturbation gravitational wave inflation

Bone fragility in type 2 diabetes mellitus

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World Journal of Orthopedics 2010年第1期1卷 3-9页

作者： Toru yamaguchi Internal Medicine 1 Shimane University Faculty of MedicineShimane 693-8501Japan

The number of patients with osteoporosis or type 2 diabetes mellitus(T2DM)is increasing in aging and westernized *** disorders predispose elderly people to disabling conditions by causing fractures and vascular complications,*** is well documented that bone metabolism and glucose/fat metabolism are etiologically related to each other through osteocalcin action and Wnt *** fragility in T2DM,which is not reflected by bone mineral density(BMD),depends on bone quality deterioration rather than bone mass ***,surrogate markers are needed to replace the insensitivity of BMD in assessing fracture risks of T2DM ***,the endogenous secretory receptor for advanced glycation endproducts,and insulin-like growth factor-I seem to be such candidates,although further studies are required to clarify whether or not these markers could predict the occurrence of new fractures of T2DM patients in a prospective fashion.

关键词： Osteoporosis Type 2 diabetes mellitus Fracture risk Osteocalcin Wnt signaling