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Biochar 2022年第1期4卷 490-502页

作者： Haixin Guo sohei ogawa Yukiya Isoda Feng Shen Richard Lee Smith Jr Ministry of Agriculture and Rural Affairs Agro-Environmental Protection InstituteNo.31 Fukang RoadNankai DistrictTianjin 300191China Graduate School of Environmental Studies Tohoku UniversityAramaki Aza Aoba 6-6-11AobaSendai 980-8579Japan

Many types of sustainably-prepared functional biochar catalysts are needed to transform biomass substrates into platform *** this work,weak-acid biochar catalysts were prepared by mix ball-milled(10 min,isothermal,room temperature)cherry blossom tree leaf biomass(BM)with humic acid(H)prior to carbonization of samples for 1 h under nitrogen *** of the as-prepared materials(HBM-carbonization temperature in℃)showed that humic acid activated the biochars and increased their number of oxygen-containing functional(-COOH,OH)*** weak-acid biochars were applied as heterogeneous catalysts for dehydration of fructose to 5-hydroxymethylfurfural(5-HMF),where it was found that biochar catalyst,HBM-400,gave 100%fructose conversion and 77.5%5-HMF yields in an ionic liquid(1-butyl-3-methylimidazolium chloride)reaction system(140℃,60 min reaction time).As-prepared HBM-400 biochars exhibited constant catalytic activity for fructose dehydration with repeated use without any type of reactivation treatment and were stable for 5 *** acid is an effective additive for preparing weak-acid catalytic materials from waste biomass.

关键词： Humic acid Mixing ball milling Oxygen-containing functional group Weak-acid biochar

Estimations of the Maximum Tangential Velocity V_(θm) in the Vortex Core Region and also the Mean Rotational Velocity V_(oi) near the Concave Wall Surface in the Returned Flow Type Cyclone Dust Collector

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Journal of Thermal Science 2010年第6期19卷 553-560页

作者： Akira ogawa T 110-0011. Minowa 2-14-7 Taitou-Ku Tokyo Japan

There are many types of cyclone dust collectors for separating the fine solid and dust particles from gases in the various industries and also in the home used purposes. For estimating the power loss and the collection efficiency, one of the most important factors is the maximum tangential velocity V0m in the vortex core region in the cyclone body. In order to determine V0~ by the simple method, it is useful to apply the mechanical balance of the angular momentum fluxes under the assumption of ogawa combined vortex model which is composed of the quasi-forced vortex in the vortex core region and also the quasi-free vortex surrounded the vortex core region and also under the assumption of the introduction of equivalent length Heq corresponding to the cone spaces of the cyclone body and the dust bunker. On the other hand, the mean rotational velocity Voi near the concave wall surface is also estimated by the mechanical balance of angular momentum fluxes with the moment of viscous friction force. For confirming the general applications of the obtained equations, the returned flow types cyclones changed the throat diameter D3 are designed. The material of the cyclone is the transparent acrylic resin. Therefore the inner surface of the cyclone body can be regarded as smooth surface. The comparisons of the measured velocities V~ and Voi by a cylindrical Pitot tube are shown in good agreement with those of the proposed equations. The above stated results are described in detail.

关键词： Cyclone Dust Collector Maximum Tangential Velocity Mean Rotational Velocity Angular Momentum Flux Equivalent Length Surface Frictional Force ogawa Combined Vortex Model Reynolds Number.

Effects of loading contact on electric-power generation of lead zirconate titanate piezoelectric ceramic plate

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Journal of Advanced Ceramics 2019年第4期8卷 509-518页

作者： Mitsuhiro OKAYASU Tsukasa ogawa Graduate School of Natural Science and Technology Okayama University

To better understand the generation of electric power for piezoelectric Pb Zr Ti O3(PZT)ceramic plate(?25 mm),an attempt was made to investigate experimentally and numerically electricpower generation characteristics during cyclic bending under various loading fixtures(?0–?20 mm),i.e.,different contact *** the load-contact area on the PZT ceramic leads to a nonlinear decrease in the generated *** contact area basically enhances the generated voltage,although the voltage saturates during loading when the contact area is less than?5 mm.A similar voltage is generated for?0 and?5 mm,which is attributed to strain status(ratio of compressive and tensile strain)and material failure due to different stress distribution in the PZT *** the basis of the obtained electric generation voltage,suitable loading conditions are clarified by loading with the?5 mm fixture,which generates a higher voltage and a longer lifetime of the PZT *** this approach,it is appeared that the area contact with the area ratio of 0.04(?5 mm/?20 mm)is suitable to obtain the high efficiency of the electric voltage.

关键词： piezoelectric ceramic lead zirconate titanate ceramic electric power generation

Spin-up and Spin-Down Times of Rotational Air Flow Depended on Mean Air Velocity and Surface Roughness on Inner Surface in Cylindrical Vortex Chamber

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Journal of Thermal Science 2004年第1期13卷 46-55页

作者： Akira ogawa Hiroyuki Murakami Department of Mechanical Eng.College of Eng. Nihon UniversityT-963.TokusadaTamura-machiKooriyama-CityJapanThe Marine Self Defense Forcethe Defense AgencyJapan

The spin-up time TA in the spin-up process and spin-down time TD in the spin-down process of rotational air flow in the cylindrical vortex chamber with three kinds of the artificial surface roughness were investigated. One of the most different characteristics between the smooth and rough surface conditions was the spin-down time TD. Also the transient response of the tangential velocity on the spin-up process was analyzed numerically and this result was compared with the experimental results. The above stated results are reported here in detail.

关键词： vortex chamber spin-up time spin-down time transient response surface roughness.

Control of Collection Efficiency for Axial Flow Cyclone Dust Collectors with Fixed Guide Vanes and with Funnel Shaped Exit Pipes

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Journal of Thermal Science 2006年第3期15卷 240-250页

作者： Akira ogawa Masaru Arakawa T-110-0011 Minowa 2-14-7Taitou-KuTokyoJapan SHINWA RULES Co. Ltd.Sanjo-ShiNiigataJapan

The experimental result of the collection efficiency of the axial flow cyclone with the fixed guide vanes is lower than that with the tangential inlet pipe to the cyclone body due to the weak angular momentum transfer given by flowing through the guide vanes. However, one of the interesting points is the control of the collection efficiency depended on the funnel shaped exit pipes. The collection efficiencies for these funnel shaped exit pipes are depended on the Froude number. Then, in this paper, the experimental results of the pressure drop and also the collection efficiency using the fly-ash particles and also the comparison of the calculated results of the collection efficiency with the experimental results are described i~ detail.

关键词： Axial flow cyclone funnel shaped exit pipe fixed guide vanes pressure drop collection efficiency,Froude number cut-Size

Surgery for scar revision and reduction:from primary closure to flap surgery

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Burns & Trauma 2019年第1期7卷 58-65页

作者： Rei ogawa Department of Plastic Reconstructive and Aesthetic SurgeryNippon Medical School1-1-5 Sendagi Bunkyo-kuTokyo 113-8603Japan

Scars are the final result of the four processes that constitute cutaneous wound healing,namely,coagulation,inflammation,proliferation,and *** scars are produced if the wounds reach the reticular *** nature of these scars depends on the four wound healing *** the remodeling process is excessive,collagen degradation exceeds collagen synthesis and atrophic scars are *** the inflammation phase is prolonged and/or more potent for some reason,inflammatory/pathological scars such as keloids or hypertrophic scars can *** these pathological scars are located on joints or mobile regions,scar contractures can *** used with the appropriate timing and when selected on the basis of individual factors,surgical techniques can improve mature *** review paper focuses on the surgical techniques that are used to improve mature scars,burn scars,and scar *** methods include z-plasties,w-plasties,split-thickness skin grafting,full-thickness skin grafting,local flaps(including the square flap method and the propeller flap),and expanded flaps,distant flaps,regional flaps,and free flaps.

关键词： Scar Keloid Hypertrophic scar Scar contracture Surgery Z-plasty W-plasty Local flap Expander Perforator flap

Fatigue Property of Additively Manufactured Ti-6Al-4V under Nonproportional Multiaxial Loading

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 76-84页

作者： Yuya Kimura Fumio ogawa Takamoto Itoh Graduate School of Science&Engineering Ritsumeikan UniversityShiga 5258577Japan Fracture and Reliability Research Institute Graduate School of Tohoku UniversityMiyagi 9808579Japan Department of Mechani-cal Engineering Ritsumeikan UniversityShiga 5258577Japan

The low cycle fatigue strength properties of the additively manufactured Ti-6Al-4V alloy are experimentally investi-gated under proportional and nonproportional multiaxial *** fatigue tests were conducted using hollow cylinder specimens with and without heat treatments,at room temperature in *** fatigue tests were conducted:one for proportional loading and one for nonproportional *** proportional loading was represented by a push-pull strain path(PP)and the nonproportional loading by a circle strain path(Cl).The failure lives of the additively manufactured specimens were clearly reduced drastically by internal voids and ***,the sizes of the defects were measured,and the defects were found not to cause a reduction in fatigue strength above a critical *** fracture surface was observed using scanning electron microscopy to investigate the fracture mechanisms of the additively manufactured specimens under the two types of strain *** fracture patterns were recognized for each strain paths;however,both showed retention of the crack propagation,despite the presence of numerous defects,probably because of the interaction of the *** crack propagation properties of the materials with numerous defects under nonproportional multiaxial loading were clarified to increase the reliability of the additively manufactured components.

关键词： Additive manufacturing Ti-6Al-4V Low cycle fatigue Multiaxial stress Nonproportional loading Internal defect

Investigation of Inside-Out Tracking Methods for Six Degrees of Freedom Pose Estimation of a Smartphone in Augmented Reality

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Computers, Materials & Continua 2024年第5期79卷 3047-3065页

作者： Chanho Park Takefumi ogawa Graduate School of Engineering The University of TokyoTokyo113-0033Japan Information Technology Center The University of TokyoChiba277-0882Japan

Six degrees of freedom(6DoF)input interfaces are essential formanipulating virtual objects through translation or rotation in three-dimensional(3D)space.A traditional outside-in tracking controller requires the installation of expensive hardware in *** inside-out tracking controllers have been proposed,they often suffer from limitations such as interaction limited to the tracking range of the sensor(e.g.,a sensor on the head-mounted display(HMD))or the need for pose value modification to function as an input interface(e.g.,a sensor on the controller).This study investigates 6DoF pose estimation methods without restricting the tracking range,using a smartphone as a controller in augmented reality(AR)*** approach involves proposing methods for estimating the initial pose of the controller and correcting the pose using an inside-out tracking *** addition,seven pose estimation algorithms were presented as candidates depending on the tracking range of the device sensor,the tracking method(e.g.,marker recognition,visual-inertial odometry(VIO)),and whether modification of the initial pose is *** two experiments(discrete and continuous data),the performance of the algorithms was *** results demonstrate enhanced final pose accuracy achieved by correcting the initial ***,the importance of selecting the tracking algorithm based on the tracking range of the devices and the actual input value of the 3D interaction was emphasized.

关键词： Smartphone inside-out tracking 6DoF pose 3D interaction augmented reality

Spermatogonial stem cells： progress and prospects

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Asian Journal of Andrology 2015年第5期17卷 771-775,I0007-I0008页

作者： Mitsuru Komeya Takehiko ogawa Department of Urology Graduate School of Medicine Yokohama City University Yokohama 236-0004 Japan Laboratory of Proteomics Institute of Molecular Medicine and Life Science Yokohama City University Association of Medical Science Yokohama 236-0004 Japan

Twenty years ago, the transplantation of spermatogonial stem cells （SSCs） from a mouse to other recipient mice was shown to be feasible, which clearly demonstrated the functional identity of SSCs. Since then, several important new findings and other technical developments have followed, which included a new hypothesis on their cell kinetics and spermatogonial hierarchy in the testis, a culture method allowing their self-renewal and proliferation, a testis tissue organ culture method, which induced their complete differentiation up to sperm, and the in vitro induction of germ cells from embryonic stem cells and induced pluripotent stem cells. These advancements reinforced or advanced our understanding of this unique cell. Nonetheless, there are many unresolved questions in the study of spermatogonial stem cells and a long road remains until these cells can be used clinically in reproductive medicine.

关键词： in vitro spermatogenesis male infertility organ culture

An extended computational approach for point-defect equilibria in semiconductor materials

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npj Computational Materials 2022年第1期8卷 746-756页

作者： Takafumi ogawa Ayako Taguchi Akihide Kuwabara Nanostructures Research Laboratory Japan Fine Ceramics Center2-4-1 MutsunoAtsuta-kuNagoya456-8587Japan

Concentrations of intrinsic and extrinsic point defects in crystalline materials with a bandgap are typically calculated in a constant-μapproach from defect formation energies based on density functional *** this work,calculations of thermal and charge equilibria among point defects are extended to a constant-N *** two approaches for point-defect equilibria are comparatively demonstrated in the application to Mg_(2)Si doped with Li,Na,and Ag,which is a lightweight and environmentally friendly thermoelectric candidate *** results reveal the systematic behavior of defect and carrier *** dopant atoms form interstitial defects at similar concentrations to substitutional defects at the Mg sites,resulting in significantly reduced free-carrier concentrations compared to the expected *** developed procedures could be utilized to find an optimal avenue for achieving higher carrier concentrations,e.g.,with regard to annealing temperature and the concentration of dopant atoms,in various semiconductors and insulators.

关键词： defect equilibria point