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91.
Hiroyuki Kameda Jinwang Li Dam Hieu Chi Ayumi Sugiyama Koichi Higashimine Tomoya Uruga Hajime Tanida Kazuo Kato Toshihiko Kaneda Takaaki Miyasako Eisuke Tokumitsu Tadaoki Mitani Tatsuya Shimoda 《Journal of the European Ceramic Society》2012,32(8):1667-1680
We report a novel low-temperature crystallization path for perovskite lead zirconate titanate (PZT) from solution. The modification of a PZT solution by monoethanolamine (MEA) resulted in a change in the crystallization behavior. MEA was strongly coordinated to the metal ions, resulting in destroy of multinuclear metal organic complexes. This led to a remarkably increased pyrolysis temperature, and Pb2+ was reduced into Pb0 because of a reducing environment at 200–300 °C. Nanoscopic separations of Pb0 was later transformed into uniformly distributed α-PbO nanocrystals and clusters in the amorphous Zr/Ti–O matrix, and finally the sample crystallized into perovskite at 400–500 °C. On the other hand, pyrochlore phase was observed in the conventional crystallization process. The avoidance of pyrochlore formation is the key for the low-temperature crystallization of perovskite. X-ray absorption fine structure (XAFS) analysis was performed to reveal the structures in solutions and amorphous phases. 相似文献
92.
Dr. Hiroyuki Shinchi Tomoya Nakamura Hayato Ota Prof. Shoko Nishihara Dr. Masahiro Wakao Prof. Yasuo Suda 《Chembiochem : a European journal of chemical biology》2019,20(14):1810-1816
Developing methods to determine cell type and cell state has been a significant challenge in the field of cancer diagnosis as well as in typing and quality verification for cultured cells. Herein, we report a cell profiling method based on binding interactions between cell-surface sugar-chain-binding proteins and sugar-chain-immobilized fluorescent nanoparticles (SFNPs), together with a method for cell typing and cell quality verification. Binding profiles of cells against sugar chains were analyzed by performing flow cytometry analysis with SFNPs. Discrimination analysis based on binding profiles could classify cell type and evaluate the quality of cultured cells. By applying our method to differentiated cells originating from conventional cell lines and also to mouse embryotic stem cells, we could detect the cells before and after differentiation. Our method can be utilized not only for the biofunctional analysis of cells but also for diagnosis of cancer cells and quality verification of cultured cells. 相似文献
93.
Tomoyuki Ikai Tomoya Kudo Masahiro Nagaki Tomoyuki Yamamoto Katsuhiro Maeda Shigeyoshi Kanoh 《Polymer》2014
A series of dithieno[3,2-b:2′,3′-d]silole-based π-conjugated copolymers containing thieno[3,4-c]pyrrole-4,6-dione or thieno[3,4-b]thiophene units bearing 4-substituted phenyl pendants were synthesized and their thermal stability, optical properties and frontier orbital energy levels were systematically investigated. The introduction of electron-withdrawing substituents on the phenyl rings lowered their frontier orbital energy levels without deteriorating their thermal and optical properties. By replacing an electron-donating methoxy group with an electron-withdrawing trifluoromethyl group, both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital energy levels of the polymers were deepened by more than 0.3 eV. A relatively linear relationship was observed between the HOMO energy levels and the Hammett substituent constants. 相似文献
94.
Kei Ikeda-Murakami Naoto Tani Tomoya Ikeda Yayoi Aoki Takaki Ishikawa 《International journal of molecular sciences》2022,23(3)
Caffeine, a common ingredient in energy drinks, crosses the blood–brain barrier easily, but the kinetics of caffeine across the blood–cerebrospinal fluid barrier (BCSFB) has not been investigated. Therefore, 127 autopsy cases (Group A, 30 patients, stimulant-detected group; and Group B, 97 patients, no stimulant detected group) were examined. In addition, a BCSFB model was constructed using human vascular endothelial cells and human choroid plexus epithelial cells separated by a filter, and the kinetics of caffeine in the BCSFB and the effects of 4-aminopyridine (4-AP), a neuroexcitatory agent, were studied. Caffeine concentrations in right heart blood (Rs) and cerebrospinal fluid (CSF) were compared in the autopsy cases: caffeine concentrations were higher in Rs than CSF in Group A compared to Group B. In the BCSFB model, caffeine and 4-AP were added to the upper layer, and the concentration in the lower layer of choroid plexus epithelial cells was measured. The CSF caffeine concentration was suppressed, depending on the 4-AP concentration. Histomorphological examination suggested that choroid plexus epithelial cells were involved in inhibiting the efflux of caffeine to the CSF. Thus, the simultaneous presence of stimulants and caffeine inhibits caffeine transfer across the BCSFB. 相似文献
95.
The possibility to apply the active hub-flap control method, which is a proven rotating stall control method for a single-stage compressor, to a 3-stage axial compressor is experimentally discussed, where complex rotating stall inception processes are observed. The research compressor is a 3-stage one and could change the stagger angle settings for rotor blades and stator vanes. Sixteen rotor blade/stator vane configuration patterns were tested by changing stagger angle for the stator vanes. By measurement of surface-pressure fluctuation, stall inception proc- esses are investigated and the measured pressure fluctuation data is used as a predictive signal for rotating stall. The experimental results show that the stall detection system applied to active hub-flap control in a single-stage compressor could be usefully applied to that in a 3-stage compressor with a more complex stall inception process. 相似文献
96.
Toshiyuki Matsunaga Noboru Yamada Rie Kojima Shinichi Shamoto Masugu Sato Hajime Tanida Tomoya Uruga Shinji Kohara Masaki Takata Peter Zalden Gunnar Bruns Ilya Sergueev Hans Christian Wille Raphaël Pierre Hermann Matthias Wuttig 《Advanced functional materials》2011,21(12):2232-2239
Crystallization of an amorphous solid is usually accompanied by a significant change of transport properties, such as an increase in thermal and electrical conductivity. This fact underlines the importance of crystalline order for the transport of charge and heat. Phase‐change materials, however, reveal a remarkably low thermal conductivity in the crystalline state. The small change in this conductivity upon crystallization points to unique lattice properties. The present investigation reveals that the thermal properties of the amorphous and crystalline state of phase‐change materials show remarkable differences such as higher thermal displacements and a more pronounced anharmonic behavior in the crystalline phase. These findings are related to the change of bonding upon crystallization, which leads to an increase of the sound velocity and a softening of the optical phonon modes at the same time. 相似文献
97.
Chu-Chen Chueh Tomoya Higashihara Jung-Hsun Tsai Mitsuru Ueda Wen-Chang Chen 《Organic Electronics》2009,10(8):1541-1548
The electronic properties, morphology and optoelectronic device characteristics of conjugated diblock copolythiophene, poly(3-hexylthiophene)-block -poly(3-phenoxymethylthiophene) (P3HT-b-P3PT), are firstly reported. The polymer properties and structures were explored through different solvent mixtures of chloroform (CHCl3), dichlorobenzene (DCB), and CHCl3:DCB (1:1 ratio). The absorption maximum (λmax) of P3HT-b-P3PT prepared from DCB was around 554 nm with a shoulder peak indicative for the highly crystalline structure around 604 nm while that from CHCl3 was 516 nm without the clear shoulder peak. The field-effect hole mobility of P3HT-b-P3PT increased from ~6.0 × 10?3, ~8.0 × 10?3 to ~2.0 × 10?2 cm2 V?1 s?1 as the DCB content in the solvent mixture enhanced. The AFM images suggested that the highly volatile CHCl3 processing solvent led to the amorphous structure, on the other hand, less volatile DCB resulted in the largely crystalline structure of the P3HT-b-P3PT. Such difference on the polymer structure and hole mobility led to the varied power conversion efficiency (PCE) of the photovoltaic cells fabricated from the blend of P3HT-b-P3PT/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) (1:1, w/w): 1.88 (CHCl3), 2.13 (CHCl3:DCB (1:1)), and 2.60% (DCB). The PCBM blend ratio also significantly affected the surface structure and the solar cell performance. The PCE of polymer/PCBM could be improved to 2.80% while the ratio of polymer to PCBM went to 1:0.7. The present study suggested that the surface structures and optoelectronic device characteristics of conjugated diblock copolymers could be easily manipulated by the processing solvent, the block segment characteristic, and blend composition. 相似文献
98.
The synthesis of a new coil–rod–coil ABA triblock copolymers comprised of regioregular poly(3-hexylthiopene) (P3HT) and poly(methyl methacrylate) (PMMA) segments has been demonstrated by the combination of quasi-living Grignard metathesis (GRIM) polymerization and living anionic polymerization based on 1,1-diphenylethylene (DPE) chemistry. The method involves simple reaction steps, an in situ introduction of DPE moieties at the α,ω-ends of P3HT and the lithiation with sec-butyl lithium (sec-BuLi) to generate a macroinitiator bearing 1,1-diphenylalkyl anions, followed by cross-over to MMA. The selective α,ω-ends di-functionalization is a key step to achieve the ABA structure. The structural homogeneity of the precursor and block copolymer has been confirmed by gel permeation chromatography (GPC), GPC-right angle laser light scattering (RALLS), and nuclear magnetic resonance (NMR). The block copolymer has been fully characterized by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), Ultra-violet–visible (UV–vis) and photo luminescent (PL) spectroscopies, and atom force microscopy (AFM). 相似文献
99.
Tomoya Inoue Yuta Nemoto Takako Nagase Yasuhisa Hasegawa Yoshimichi Kiyozumi Koichi Sato Masateru Nishioka Satoshi Hamakawa Toshikazu Nishide Fujio Mizukami 《Korean Journal of Chemical Engineering》2008,25(3):437-442
We successfully developed zeolite membranes with hydrophilic character, by choosing appropriate zeolites in terms of hydrophilicity
and high acid tolerance. We evaluated thus developed membranes by their pervaporation (PV) performance, dehydration from acidic
organic solvent. The zeolite membranes we developed, based on merlinoite (MER), chabazite (CHA) or phillipsite (PHI), are
shown to exhibit stable dehydration performance, respectively. We successfully applied the membranes to the selective removal
of water in an ester condensation reaction starting from a stoichiometric mixture of a carboxylic acid and an alcohol. The
availability of pervaporation-assisted ester condensation reaction was validated by various kinds of combinations of carboxylic
acid and alcohols, which implies the general availability of pervaporation-assisted process intensification by zeolite membranes.
This paper was presented at the 11th Korea-Japan Symposium on Catatysis held at Seoul, Korea, May 21–24, 2007. 相似文献
100.
Akira Hirao Kaori Kawasaki Tomoya Higashihara 《Science and Technology of Advanced Materials》2013,14(4):469-477
We have developed a novel methodology using polymer anions specially designed to comprise either of the three same or different polymer segments for the synthesis of well-defined regular and asymmetric star-shaped polymers. The polymer anion was prepared by the addition reaction of living anionic polymer to in-chain-functionalized polymer with 1,1-diphenylethylene (DPE) moiety and in situ coupled with chain-end-functionalized polystyrene with two or four benzyl bromide moieties. Although the anions located at the cores of 3-armed star polymers were believed to be highly sterically hindered, the coupling reactions proceeded virtually quantitatively under the conditions in THF at – 78 °C for 24 h. Regular 7-armed A7 and 13-armed A13 star-shaped polystyrenes as well as quite new asymmetric 7-armed A2B2C2D and 13-armed A4B4C4D star-shaped polymers were synthesized in ca. 100% yields. Four polymer segments, A, B, C, and D, were, poly(4-trimethylsilylstyrene), poly(4-methoxystyrene), poly(4-methylstyrene), and polystyrene prepared by sec-BuLi-initiated living anionic polymerization. Thus, three same or different polymer chains could be simultaneously introduced into either two or four benzyl bromide reaction sites only by one-step coupling reaction with the above-prepared polymer anion. The resulting star-shaped polymers all were well-defined in architecture and precisely controlled in-chain length and composition. Accordingly, they have a high molecular weight and structural homogeneity. Among them, asymmetric star-shaped polymers synthesized herein are the first successful examples comprised of four plural different polymer segments. As expected, new morphologies with nanoscopic ordered structures applicable to nanotechnology have been expressed. 相似文献