检索结果-南通市图书馆

International Journal of Minerals,Metallurgy and Materials 2020年第12期27卷 1635-1643页

作者： Eltefat Ahmadi Ryosuke O.Suzuki Tatsuya Kikuchi Takumi Kaneko yuta Yashima Division of Materials Science and Engineering Faculty of EngineeringHokkaido UniversitySapporo 060-8628Japan Japan Society for the Promotion of Science(JSPS) Tokyo 102-0083Japan

A new concept for producing highly pure Ti metal powder from ilmenite(FeTiO)_(3))is proposed in this *** nitride(TiN)or titanium oxycarbonitride(TiO_(x)C_(y)N_(z))could be synthesized in the first step via the simultaneous carbothermal reduction and nitridation(CTRN)of FeTiO3 to remove oxygen *** separate oxygen completely,high-quality TiS2 samples were then synthesized from TiN and TiC using S2 gas,and the clean sulfides were finally reduced toα-Ti powders with spherical morphology using electrolysis in molten CaCl_(2).Xray diffraction(XRD),scanning electron microscopy(SEM)in conjunction with energy-dispersive X-ray spectroscopy(EDS),and elemental LECO analysis were used to study the phases and microstructures of the sulfides and the electrochemically reduced *** Ti powder showed no carbon contamination and consisted of high-purity foil-like Ti sheets with very low oxygen,carbon,and nitrogen contents of less than 0.15 wt%O,0.02 wt%C,and 0.003 wt%N,*** quality of the Ti powder was much higher than that of the powder obtained using the conventional OS process(proposed by *** and ***)starting directly from the oxides.

关键词： titanium molten salt electrolysis sulfidation titanium oxycarbonitride ilmenite

Synthesis and TEM structural characterization of C60-flattened carbon nanotube nanopeapods

在线全文

学校读者我要写书评

暂无评论

Nano Research 2014年第12期7卷 1843-1848页

作者： Qing Wang Ryo Kitaura yuta Yamamoto Shigeo Arai Hisanori Shinohara Department of Chemistry & Institute for Advanced Research Nagoya University Nagoya 464-8602 Japan High Voltage Electron Microscope Laboratory Ecotopia Science Institute Nagoya University Nagoya 464-8602 Japan

A fully flattened carbon nanotube （FNT）, a graphene nanoribbon （GNR） analogue, provides a hollow space at edges for endohedral doping. Due to the unique shape of the hollow space of FNTs, novel types of low-dimensional arrangements of atoms and molecules can be obtained through endohedral doping into FNTs, which provides a new type of nanopeapods. FNT-based nanopeapods have been synthesized through endohedral doping of C60, and their structural characterization with transmission electron microscopy （TEM） performed. The doping of C60 into the inner hollow space of FNTs has been carried out via the gas-phase filling method, where open-ended FNTs are sealed in a glass ampoule and heated at 723-773 K for two days. TEM observations show that most of the encapsulated C60 molecules align as single molecular chains along the edges of FNTs and that some of the C60 forms two-dimensional close-packed structures inside FNTs.

关键词： carbon nanotubes nanopeapods endohedral doping electron microscopy

地闪回击电磁场受建筑物宽度和相对位置的影响分析

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

江西科学 2024年第3期42卷 648-653页

作者：王荣珠赖悦李玉塔夏雪江西省气候中心南昌330046 北京市气象探测中心北京100089

在雷电监测预警工作中,由于地形限制,雷电监测系统通常布置于建筑物顶部,会导致系统反演的雷电参数误差较大,因此,通过仿真模拟手段定量分析影响程度,为定位结果的校正提供参考。基于时域有限差分法(FDTD),研究了建筑物的宽度和相对位... 详细信息

在雷电监测预警工作中,由于地形限制,雷电监测系统通常布置于建筑物顶部,会导致系统反演的雷电参数误差较大,因此,通过仿真模拟手段定量分析影响程度,为定位结果的校正提供参考。基于时域有限差分法(FDTD),研究了建筑物的宽度和相对位置对闪电回击电磁场的影响,绘制了建筑物的宽度与垂直电场增大比例之间的关系式以及拟合曲线。结果表明,垂直电场的增量M在建筑物宽度增加时减少,当建筑物宽度增加到一定程度时,仍保持在较小范围内;当建筑物与闪电通道之间的距离d增加到3.22 km时,建筑物的宽度对建筑物顶部垂直电场值影响可忽略不计。研究结果对提高雷电定位系统精度有一定参考价值。

关键词：建筑物宽度相对位置回击电磁场

CFD Simulation of Pulsation Noise in a Small Centrifugal Compressor with Volute and Resonance Tube

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2015年第1期24卷 24-29页

作者： Daich Wakaki yuta Sakuka Yuzo Inokuchi Kosuke Ueda Nobuhiko Yamasaki Akihiro Yamagata Kyushu University IHI Corporation

The rotational frequency tone noise emitted from the automobile turbocharger is called the pulsation noise. The cause of the pulsation noise is not fully understood, but is considered to be due to some manufacturing errors, which is called the mistuning. The effects of the mistuning of the impeller blade on the noise field inside the flow passage of the compressor are numerically investigated. Here, the flow passage includes the volute and duct located downstream of the compressor impeller. Our numerical approach is found to successfully capture the wavelength of the pulsation noise at given rotational speeds by the comparison with the experiments. One of the significant findings is that the noise field of the pulsation noise in the duct is highly one-dimensional although the flow fields are highly three-dimensional.

关键词： Pulsation Tone Noise CFD URANS Centrifugal Compressor Turbocharger Volute

Prediction of Acoustic Absorption Performance of a Perforated Plate with Air Jets

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2017年第4期26卷 378-384页

作者： Hiromitsu Hamakawa Masanori Miyazaki yuta Asai Eru Kurihara Eiichi Nishida Hidechito Hayashi Department of Mechanical Engineering Oita University700 DannoharuOita 870-1192Japan Graduate Student Oita University700 DannoharuOita 870-1192Japan Department of Mechanical Systems Engineering Shonan Institute of Technology1-1-25 Tsujido-NishikaiganFuji-sawaKanagawa 251-8511Japan Department of Mechanical Engineering Nagasaki University1-14 Bunkyo machiNagasaki852-8521Japan

The present study focuses on the prediction of acoustic absorption performance of a perforated plate with air jets by theoretical calculations. In addition, we experimentally measured the flow rate, internal pressure, acoustic pressure, and transfer function using an acoustic impedance tube. The normal incidence absorption coefficient was calculated from the measured transfer function using transfer function methods. We investigated the influences of background air space, flow velocity, thickness, aperture rate, and aperture diameter of a perforated plate on the acoustic absorption characteristics. The frequency characteristics of the acoustic absorption coefficient showed a maximum value at a local frequency. As the background air space increased, the peak frequency of acoustic absorption characteristics decreased. As the flow velocity passing through the apertures increased, the peak level of the acoustic absorption coefficient also increased. The theoretical results agreed well with the experimental ones qualitatively.

关键词： acoustic absorption perforated plate theoretical prediction acoustic impedance tube air jets

Machine learning of organic solvents reveals an extraordinary axis in Hansen space as indicator of spherical precipitation of polymers

在线全文

学校读者我要写书评

暂无评论

Aggregate

Aggregate 2023年第5期4卷 207-213页

作者： yuta Ihara Hiroshi Yamagishi Masanobu Naito Yohei Yamamoto Department of Materials Science Faculty of Pure and Applied Sciencesand Tsukuba Research Center for Energy Materials Science(TREMS)University of TsukubaTsukubaJapan Research and Services Division of Materials Data and Integrated System(MaDIS) National Institute for Materials Science(NIMS)TsukubaJapan Program in Materials Science and Engineering Graduate School of Pure and Applied SciencesUniversity of TsukubaTsukubaJapan

Machine learning is an emerging tool in the field of materials chemistry for uncovering a principle from large ***,we focus on the spherical precipitation behavior of polymers and computationally extract a hidden trend that is orthogonal to the availability bias in the chemical *** constructing a dataset,four polymers were precipitated from 416 solvent/nonsolvent combinations,and the morphology of the resulting precipitates were *** dataset was subjected to computational investigations consisting of principal component analysis and machine learning based on random forest model and support vector ***,we eliminated the effect of the availability bias and found a linear combination of Hansen parameters to be the most suitable variable for predicting precipitation *** predicted appropriate solvents are those with low hydrogen bonding capability,low polarity,and small molecular ***,we found that the capability for spherical precipitation is orthogonal to the availability bias and forms an extraordinary axis in Hansen space,which is the origin of the conventional difficulty in identifying the *** extraordinary axis points toward a void region,indicating the potential value of synthesizing novel solvents located therein.

关键词： chemical space computational chemistry machine learning polymers precipitation

Anisotropic brittle-ductile transition of monocrystalline sapphire during orthogonal cutting and nanoindentation experiments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nanotechnology and Precision Engineering 2018年第3期1卷 157-171页

作者： Philipp Maas yuta Mizumoto Yasuhiro Kakinuma Sangkee Min Department of System Design Engineering Faculty of Science & TechnologyKeio University Department of Mechanical Engineering University of Wisconsin-Madison

Single-crystal sapphire is utilized as a high-performance engineering material,especially in extreme and harsh ***,due to its extreme hardness and brittleness,the machinability of sapphire is still a *** means of nanoindentation and plunge-cut experiments,the anisotropic brittle-ductile transition of the prismatic M-plane and rhombohedral R-plane is examined by analyzing crack morphologies and the critical depth-of-cut(CDC).The experimental results of the nanoindentation tests are correlated to the plunge-cut *** the prism plane and the rhombohedral crystal plane exhibit a two-fold symmetry of ductility with various crack patterns along the machined *** direction-dependent plasticity of the hexagonal sapphire crystal is mainly connected to a twinning process accompanied by slip dislocation.

关键词： Sapphire Anisotropy Brittle-ductile transition Orthogonal cutting

Regional management and biodiversity conservation in GIAHS:text analysis of municipal strategy and tourism management

在线全文

学校读者我要写书评

暂无评论

Ecosystem Health and Sustainability 2019年第1期5卷 124-132,I0019页

作者： Ryo Kohsaka Hikaru Matsuoka yuta Uchiyama Marie Rogel Graduate School of Environmental Studies Nagoya UniversityNagoyaJapan Institute of Science and Engineering Kanazawa UniversityKanazawaJapan Graduate School of Environmental Studies Tohoku UniversitySendaiJapan

Purpose of the research:To identify the gaps between the rhetoric and reality of the role of citizen participation and its role in maintenance and monitoring of heritages and resources(including biodiversity monitoring),we analyzed the discourse of Globally Important Agricultural Heritage System(GIAHS)at municipality ***:As an analytical framework,text mining is applied to interviews of officers at the municipal level of GIAHS in Noto which was amongst the first sites in *** identification of such gap is critical for sustainability and to prevent conflicts from tourism,agriculture or ***:The results reveal that(1)there is a gap between the official goals of that designation at the international level and local needs,(2)role of citizens is emphasized in the applications and action plans at rhetorical level but remain rather limited in practice and that(3)municipalities composing the GIAHS often have different priorities,even within the very same GIAHS sites,some municipalities even calling themselves“just a transition point to other destination municipalities.”Conclusions:It is critical for municipal officers to collaborate with various stakeholders,especially *** such,citizen science is a bottom-up approach to promote biodiversity conservation and facilitate GIAHS managements.

关键词： Municipality global institution GIAHS text mining co-occurrence analysis correspondence analysis

Self-interstitials generated on silicon bulk surface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2011年第1期21卷 17-20页

作者： Yukihiro KATO Ryoji FUKUDA yuta TAKENO Toshitada SHIMOZAKI Takahisa OKINO Department of Design Engineering Semiconductor Business DivisionMitsumi Electric Co.LtdAtugi 243-0004Japan Department of Architecture and Mechatronics Faculty of EngineeringOita UniversityOita 870-1192Japan Department of Materials and Technology Kyushu Institute of TechnologyKitakyushu 804Japan

The self-interstitial atoms in silicon generated by the bulk surface oxidation diffuse into the bulk inside and affect the phenomena such as the diffusions and the stacking *** generation rate of self-interstitials(Rgen) depends on theωpower of the oxidation film growth rate dX0/*** physical quantityωis important to understand the material science relevant to self-interstitials in the silicon ***,the conclusiveωvalue is not reported,although variousωvalues to control the generation rate have been *** the present study,the chemical reaction equation is analytically solved,and using the result,the oxidation stacking fault radius(r) is analytically expressed against the oxidation time(t).Comparing the obtained relation of r=r(t) with the experimental results of the stacking faults,the analytical expression of co is determined and the physical meaning ofωis ***,the temperature dependence ofωis also numerically determined.

关键词： silicon self-interstitial vacancy oxide impurity diffusion stacking fault

Automated crystal structure analysis based on blackbox optimisation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2020年第1期6卷 1022-1028页

作者： Yoshihiko Ozaki yuta Suzuki Takafumi Hawai Kotaro Saito Masaki Onishi Kanta Ono Artificial Intelligence Research Center(AIRC) National Institute of Advanced Industrial Science and Technology(AIST)TokyoJapan GREE Inc.TokyoJapan Institute of Materials Structure Science(IMSS) High Energy Accelerator Research Organization(KEK)IbarakiJapan SOKENDAI(The Graduate University for Advanced Studies) IbarakiJapan Paul Scherrer Institute VilligenSwitzerland Medley IncTokyoJapan

In the present study,we show that time-consuming manual tuning of parameters in the Rietveld method,one of the most frequently used crystal structure analysis methods in materials science,can be automated by considering the entire trial-and-error process as a blackbox optimisation *** automation is successfully achieved using Bayesian optimisation,which outperforms both a human expert and an expert-system type automation despite the absence of *** approach stabilises the analysis quality by eliminating human-origin variance and bias,and can be applied to various analysis methods in other areas which also suffer from similar tiresome and unsystematic manual tuning of extrinsic parameters and human-origin variance and bias.

关键词： analysis black structure