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Controllable fabrication of carbon aerogels

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Rare Metals 2006年第Z1期25卷 284-288页

作者： TANEMURA Sakae TANEMURA Masaki SUZUKI Kenzi Department of Environmental technology & Urban Planning Nagoya Institute of Technology Showa-ku Nagoya 466-8555 Japan EcoTopia Science institute Nagoya University Chikusa-ku Nagoya Japan

Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 ℃ under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high surface area and sharp pore size distribution. Aiming to investigate the effects of preparation conditions on the gelation process, the bulk density, and the physical and chemical structure of the resultant carbon aerogels, the molar ratio of R/C (resorcinol to catalyst) and the amount of distilled water were varied, consequently two different sets of samples, with series of R/C ratio and RF/W (Resorcinol-Formaldehyde to water, or the content of reactant) ratio, were prepared. The result of N2 adsorption/desorption experiment at 77 K shows that the pore sizes decreasing from 11.4 down to 2.2 nm with the increasing of the molar ratio of R/C from 100 to 400, and/or, the pore sizes decreasing from 3.8 down to 1.6 nm with the increasing of reactant content from 0.4 to 0.6.

关键词： resorcinol-formaldehyde aerogels carbon aerogels super-critical drying N2 adsorption/desorption

Lagrangian and Eulerian Statistics from Direct Numerical Simulations of Turbulent Channel Flow

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Chinese Physics Letters 2006年第4期23卷 883-886页

作者：罗剑平 Tatsuo Ushijima Osami Kitoh nagoya institute of technology Gokiso-cho Showa-ku Nagoya 466-8555 Japan

Lagrangian and Eulerian statistics are obtained from the direct numerical simulation of a turbulent channel flow. The Reynolds number is obtained to be Reτ = 100 （based on friction velocity and channel half-height）. The Lagrangian time microscales are compared to their Eulerian equivalents. It is found that the Lagrangian time microscales equal the Eulerian time microscales at the wall, but they are consistently larger than the Eulerian away from the wall. The Eulerian time scales are also found to be scaled by the propagation velocity rather than the mean velocity. The ratio of the Lagrangian to the Eulerian time microscales is found to be nearly constant away from the wall （y^＋〉 40）.

关键词： ISOTROPIC TURBULENCE FLUID PARTICLES VELOCITY DISPERSION GRADIENT

Electrocatalytic evolution of oxygen on NiCu particles modifying conductive alumina/nano-carbon network composite electrode

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Science China(Technological Sciences) 2012年第12期55卷 3388-3394页

作者： FUJI Masayoshi SHIRAI Takashi WATANABE Hideo TAKAHASHI Minoru Ceramics Research Laboratory Nagoya Institute of Technology

In this paper, a novel electrically conductive alumina/nano-carbon network (NCN) composite material was used as an electro- catalyst carrier. A NiCu/Al2O3 /NCN composite electrode was prepared by electrodepositing NiCu particles onto the surface of the conductive alumina/NCN composite. Morphology, composition, crystalline structure and electrochemical properties of the NiCu/Al2O3 /NCN composite electrode were investigated. The results showed that NiCu particles can be deposited onto the surface of the alumina/NCN composite by a coelectrodeposition method. NiCu particles in the form of solid solution with face-centered cubic (fcc) structure were relatively uniformly distributed over the carbon layer of the conductive ceramic between alumina grains. As-resulted NiCu/Al2O3 /NCN composite electrode had a remarkably enhanced electrochemical activity and high stabilization for oxygen evolution reaction, which indicated its potential application with enhanced performance to oxygen evolution reaction (OER). Moreover, based on the electrochemical measurement, the mechanism of the OER on the NiCu/Al2O3 /NCN composite electrode was discussed.

关键词： conductive aluminafNCN electrodeposition NiCu oxygen evolution electrocatalytic activity

High-frequency magnetic characteristics of Fe-Co-based nanocrystalline alloy films

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Science China(Technological Sciences) 2010年第6期53卷 1501-1506页

作者： HIHARA Takehiko SUMIYAMA Kenji Department of Materials Science and Engineering Nagoya Institute of TechnologyNagoya 466-8555Japan

Magnetically soft Fe-Co-based nanocrystalline alloy films were produced by two preparation methods:One using a new energetic cluster deposition technique and another using a conventional magnetron sputtering *** structural,static magnetic properties and high-frequency magnetic characteristics were *** the energetic cluster deposition method,by applying a high-bias voltage to a substrate,positively charged clusters in a cluster beam were accelerated electrically and deposited onto a negatively biased substrate together with neutral clusters from the same cluster source,to form a high-density Fe-Co alloy cluster-assembled film with good high-frequency magnetic *** the conventional magnetron sputtering method,only by rotating substrate holder and without applying a static inducing magnetic field on the substrates,we produced Fe-Co-based nanocrystalline alloy films with a remarkable in-plane uniaxial magnetic anisotropy and a good soft magnetic *** obtained Fe-Co-O,Fe-Co-Ti-N,and Fe-Co-Cr-N films all revealed a high real permeability exceeding 500 at a frequency up to 1.2 *** makes Fe-Co-based nanocrystalline alloy films potential candidates as soft magnetic thin film materials for the high-frequency applications.

关键词： Fe-Co-based nanocrystalline alloy films high-frequency characteristics energetic cluster deposition magnetron sputtering substrate rotation

Numerical study on 3D effect and practical design in shield tunneling

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Underground Space 2019年第3期4卷 201-209页

作者： Hossain Md.Shahin Teruo Nakai Tetsuo Okuno Islamic University of technology GazipurBangladesh Geo-Research institute Japan nagoya institute of technology NagoyaJapan Shimizu Corporation TokyoJapan

In practice,different design methods are used in solving geotechnical problems depending on the type of issue such as the tunneling,braced excavation,or bearing capacity of a foundation,that is,the basic mechanism of the design method differs depending on the problems even for the same ground.A numerical analysis using the finite element method has recently become familiar owing to an improved computing performance;however,it is not widely used in the design of geotechnical problems including tunnel excavation owing to the reliability of the constitutive model of the ground *** a constitutive model of soils can properly express the properties of the ground material,a numerical analysis will play a vital role in solving the geotechnical *** this paper,the current state of a numerical analysis and its applicability in tunnel design are ***,the simulation of the ground behavior during tunnel excavation is carried out using sandy and clay ground parameters for shallow and deep tunnel *** paper is mainly focused on the effects of tunnel excavation under three-dimensional(3D)conditions,as well as the current design ***-linear 2D and 3D finite element analyses have been conducted,in which the elastoplastic sub-loading tij model has been used as a constitutive model of the *** performance and acceptability of the constitutive model have already been proven to reproduce the results of various model tests on different geotechnical problems such as the tunneling,braced excavation,and bearing capacity of a foundation,as well as the measured field *** was found that a 2D finite element analysis where the rate of stress release is considered,can be used for the prediction of the ground deformation and surface settlement;however,it does not provide rational information in the prediction of tunnel lining forces such as the stress,bending moment,and axial force,which emphasize the necessity of a 3D analysis with a proper cons

关键词： Shield tunneling Finite element analysis 3D effect

Micronization of curcumin with biodegradable polymer by supercritical anti-solvent using micro swirl mixer

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Frontiers of Chemical Science and Engineering 2018年第1期12卷 184-193页

作者： Kimthet Chhouk Wahyudiono Hideki Kanda Shin-Ichro Kawasaki Motonobu Goto Department of Chemical Engineering Nagoya University Nagoya 464-8603 Japan Department of Chemical Engineering and Food technology Institute of Technology of Cambodia Phnom Penh Cambodia Department of Materials Process Engineering Nagoya University Nagoya 464-8603 Japan Research institute for Chemical Engineering Process technology National Institute of Advanced Industrial Science and Technology Sendai 983-8551 Japan

Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and antimicrobial activity. In this employed to produce the work, a swirl mixer was micronized curcumin with polyvinylpyrrolidone （PVP） by the supercritical antisolvent process to improve the bioavailability of curcumin. The effects of operating parameters such as curcumin/PVP ratio, feed concentration, temperature, pressure, and CO2 flow rate were investigated. The characterization and solubility of particles were determined by using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and ultra-violet-visible spectroscopy. The result shows that the optimal condition for the production of curcumin/PVP particles is at curcumin/PVP ratio of 1：30, feed concentration of 5 mg·mL^-1, temperature of 40 ℃, pressure of 15 MPa, and CO2 flow rate of 15 mL·min^-1. Moreover, the dissolution of curcumin/PVP particles is faster than that of raw curcumin.

关键词： micronization curcumin polyvinylpyrrolidone supercritical anti-solvent swirl mixer

Electrochemical Characterization of a Porous Pt Nanoparticle ＂Nanocube-Mosaic＂ Prepared by a Modified Polyol Method with HCI Addition

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Nano Research 2011年第8期4卷 746-758页

作者： Randy Jalem Ryosuke Koike Yong Yang Masanobu Nakayama Masayuki Nogami Department of Materials Science and Engineering Nagoya Institute of Technology Showa Nagoya 466-8555 Japan

Porous and single crystalline platinum （Pt） nanoparticles （NPs） have been successfully synthesized by reduction of H2PtC16.6H20 and then investigated by optical spectroscopy and transmission electron microscopy. H2PtCI6-6H20 was reduced using ethylene glycol in the presence of polyvinylpyrrolidone under highly acidic conditions （pH 〈 1） to form single crystalline Pt particles about 5 nm in size. These particles were then stacked via {100} facets, forming 50-nm length porous nanocubes with a mosaic structure. The porous Pt NPs exhibited excellent catalytic properties for methanol oxidation. In particular, the electrochemical surface area was -63 m2/g, five times higher than that for non-porous Pt NPs prepared using a conventional method. We suggest that the high catalytic activity of porous Pt NPs is due to a combination of the crystalline structure having exposed {100} facets and a porous morphology.

关键词： Platinum porous nanoparticles catalyst methanol oxidation cyclic voltammetry

Activation of Trifluoromethylthio Moiety by Appending Iodonium Ylide under Copper Catalysis for Electrophilic Trifluoromethylation Reaction

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Chinese Journal of Chemistry 2016年第5期34卷 485-489页

作者： Ibrayim Saidalimu Shugo Suzuki Etsuko Tokunaga Norio Shibata Department of Frontier Materials nagoya institute of technology Gokiso Showa-ku Nagoya 466-8555 Japan Department of Nanopharmaceutical Sciences Nagoya Institute oF Technology Gokiso Showa-ku Nagoya 466-8555 Japan

A novel iodonium-ylide compound 2 that appends a trifluoromethylthio （SCF3） group is disclosed as a new, shelf-stable electrophilic trifluoromethylation reagent. Unlike known shelf-stable electrophilic trifluoromethylation reagents, 2 has a stable SCF3 group which is activated by appending iodonium ylide under copper catalysis via sul- fonium ylide to generate a cationic trifluoromethyl （CF3） species. Reagent 2 was found to be an efficient electro- philic trifluoromethylation reagent for a wide range of silyl enol ethers 3 under copper catalysis. Cyclic and acyclic a-trifiuoromethyl ketones 4 were obtained by reagent 2 in moderate to good yields. On the other hand, a difluoro- methylthio analogue 5 did not affect intermolecular transfer difluoromethylation to substrates. Instead, intramolecu- lar 1,4-migration proceeded similar to the Stevens rearrangement to provide 6 in 21% yield, independent of the presence of nucleophiles 3.

关键词： trifluoromethylation difluoromethylation iodine sulfur ylide

Lagrangian Structure Function＇s Scaling Exponents in Turbulent Channel Flow

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Chinese Physics Letters 2010年第2期27卷 169-171页

作者：罗剑平卢志明牛岛连夫鬼頭修己刘宇陆 Shanghai institute of technology Shanghai 200235 Shanghai institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 nagoya institute of technology Gokiso-cho Showa-ku Nagoya 466-8555 Japan

The Lagrangian structure function＇s scaling exponents and intermittency of three-dimensional incompressible turbulent channel flow are investigated by using direct numerical simulation. The intermittency in streamwise velocity increments is found to increase in the near-wall region, which can be attributed to the presence of strong mean shear and organized motions in the near-wall region. It is found that the intermittency of transverse velocity increments is weaker than that of longitudinal ones. The present ESS evaluation of ζL（q） for the structure function of the streamwise velocity component in the channel centre is fairly close to experimental estimates of isotropic turbulence.

关键词： Fluid dynamics