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排序方式: 共有1611条查询结果,搜索用时 31 毫秒
61.
62.
Shuqi Guo Yutaka Kagawa Toshiyuki Nishimura Hidehiko Tanaka 《Journal of the American Ceramic Society》2007,90(7):2255-2258
The thermal and electrical properties of MoSi2 and/or SiC-containing ZrB2 -based composites and the effects of MoSi2 and SiC contents were examined in hot-pressed ZrB2 –MoSi2 –SiC composites. The thermal conductivity and electrical conductivity of the ZrB2 –MoSi2 –SiC composites were measured at room temperature by a nanoflash technique and a current–voltage method, respectively. The results indicate that the thermal and electrical conductivities of ZrB2 –MoSi2 –SiC composites are dependent on the amount of MoSi2 and SiC. The thermal conductivities observed for all of the compositions were more than 75 W·(m·K)−1 . A maximum conductivity of 97.55 W·(m·K)−1 was measured for the 20 vol% MoSi2 -30 vol% SiC-containing ZrB2 composite. On the other hand, the electrical conductivities observed for all of the compositions were in the range from 4.07 × 10–8.11 × 10 Ω−1 ·cm−1 . 相似文献
63.
Mohammad Kamruzzaman Yutaka Kuwahara Tomonari Ogata Seiji Ujiie Seiji Kurihara 《Polymer International》2011,60(5):730-737
A new class of liquid‐crystalline poly(ethylene imine)s (PEIs) having four differently substituted (? CN,? C4H9,? OCH3 and? NO2) azobenzene side‐chain groups attached through alkyl spacer groups were successfully synthesized using a solution polycondensation reaction. The synthesized polymers were characterized using differential scanning calorimetry, polarized optical microscopy and X‐ray diffraction. The photochemical, thermo‐optical and photo‐orientational behavior of the polymers were investigated in detail. Spin‐coated films of PEIs with azobenzene groups having? C4H9,? OCH3 and? NO2 substituents showed out‐of‐plane molecular orientation on annealing. Except for the PEI with an azobenzene group having ? NO2 substituent, all polymers exhibited good photoresponsive properties upon irradiation with UV and visible light. Films of PEIs with azobenzene side groups having? CN,? C4H9 and? OCH3 substituents showed reversible alignment behavior from random state to out‐of‐plane and from out‐of‐plane to random state on annealing and on irradiation with UV and non‐polarized visible light. The reversibility of the molecular orientation of PEIs from random state to out‐of‐plane and from out‐of‐plane to random state greatly depended on the substituent attached to the azobenzene side‐chain group. Copyright © 2010 Society of Chemical Industry 相似文献
64.
Masahiro Takahashi Yutaka Kimura Mitsuki Hagiwara Keiki Kishikawa Shigeo Kohmoto 《Synthetic Metals》2011,161(15-16):1557-1562
Improved synthesis and reinvestigation of the magnetic properties of triphenylamine bearing three nitronylnitroxide radicals (1) were carried out. Single crystal X-ray crystallographic analysis of 1 established that its molecular shape had a C3-symmetry. Our newly prepared 1 showed different physical properties from those of reported. SQUID measurements of 1 showed that each of the three spins of 1 behaved independently at room temperature. In contrast, the three spins coupled antiferromagnetically at lower temperature as low as ca. 1.8 K. These spin behaviors can be explained by a regular triangular antiferromagnetic model (J/kB = ?3.3 K) and interpreted as a spin frustration system. 相似文献
65.
Ziqing Zhai Yuichi Miyahara Hiroshi Abe Yutaka Watanabe 《Metallurgical and Materials Transactions A》2014,45(13):6163-6172
The grain boundary segregation of phosphorus and alloying elements in the heat-affected zone (HAZ) of a low alloy steel was studied quantitatively with atom probe tomography. Non-equilibrium segregation mainly occurred during welding and subsequent fast cooling, leading to remarkable segregation of P, C, Mn, and Mo. The segregation of these four types of solutes showed similar microstructure-dependence at this stage, in which the segregation levels are higher in coarse-grained HAZ and intercritically reheated coarse-grained HAZ than in fine-grained HAZ. After simulated aging, P and Mn showed further enrichment at grain boundaries through equilibrium segregation, while desegregation was observed for C and Mo. In addition, it seems that precipitation of Mo at dislocations was greatly promoted during aging, which probably also contributed to the increase of P and Mn at grain boundaries. 相似文献
66.
Seiichi Takami Yasuhiro Shirai Toyohiro Chikyow Yutaka Wakayama 《Thin solid films》2009,518(2):692-694
We have proposed the synthesis of organic molecular nanowires using porous alumina as a template. We also proposed the use of a magnetic field to control the molecular packing structure in the nanowires. In this paper, we developed the method to evaluate the electronic properties of the nanowire of a phthalocyanine derivative that was synthesized using porous alumina as a template. The developed method facilitates the study in the organic molecular nanowires that were synthesized using templates and helps their use in future electronic devices. 相似文献
67.
Sunnam Kim Wataru Inoue Satoshi Hirano Ryohei Yagi Yutaka Kuwahara Tomonari Ogata Seiji Kurihara 《Polymer》2014
Three type polymers containing the same azobenzene side chain group with different backbone structures, poly(DMAz6Fm), poly(DMAz6It) and poly(MAz6Ac) derived respectively from fumaric acid, itaconic acid and acrylic acid, were synthesized. The dependence of photo-response properties on the polymeric architecture was investigated for the solutions and films. By irradiation of the linearly polarized light (436 nm), uniaxial orientations of the thin films were induced and anisotropic properties were investigated by measurements of the order parameters and birefringence values. 相似文献
68.
Shixue Wang Yoshio Utaka Yutaka Tasaki 《International Journal of Heat and Mass Transfer》2009,52(19-20):4386-4389
An experiment was carried out to examine heat and mass transfer between constant-temperature water and dry air through a porous plate having extremely small pores. The effects of the thermal conductivity in the porous plate on moisture transport were investigated. The controlling factor for moisture transport was found to be the thermal resistance inside the porous plate having a low-thermal-conductivity and the heat transfer at the surface of the porous plate having a high-thermal-conductivity. 相似文献
69.
Kimiyoshi Naito Yutaka Kagawa Seishi Utsuno Tamaki Naganuma Kanshi Kurihara 《Composites Science and Technology》2009,69(11-12):2027-2029
Electromagnetic wave transmittances of plain woven fabric glass fiber reinforced epoxy matrix composite (PW-GFRP) and eight-harness-stain fabric glass fiber reinforced polyimide matrix composite (8H-GFRP) with 1.0 mm thickness were measured in a terahertz (THz) frequency range. The transmittance values for both composites are nearly zero at a frequency of 1.0 THz. The real parts of the complex dielectric constant, ε′(ω) are 4.45 and 3.87 for PW-GFRP and 8H-GFRP, respectively, in the frequency range from 0.2 to 1.0 THz, and they are almost frequency independent. Conversely, the imaginary parts of the dielectric constant, ε′′(ω) for both composites linearly increases with increase of the frequency from 0.13 to 0.37 for PW-GFRP, and from 0.12 to 0.33 for 8H-GFRP. 相似文献
70.