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921.
Heterogeneous nucleation of water was investigated using molecular dynamics simulation. Solid with fcc (111) surface was placed at the bottom of a cell consisting of 864 water molecules. ST2 model with NPT ensemble was used. The pressure and temperature were set to be 0.1 MPa and 275 K, respectively. The interaction between water and the solid was based on the equations proposed by Spohr. Exception was made on the lattice constant which was slightly modified to fit with that for ice structure. The shape of the solid surface was considered. It was found that the only one layer of water molecules was adsorbed in a case of a flat surface, whereas ice nucleation occurred by removing some of the atoms from the surface. Spohr's interaction was also modified so that the dipole moment of water became anti-ferroelectric. It was found that the modification increased the ice growth, further. The effect of lattice constant of solid on nucleation was also investigated. It was found that the variation on lattice constant with a few percent from that of ice was acceptable for nucleation, especially on shrinking side. On expanding side, however, it gave some gaps for water molecules to fit in other than that for ice structure, and it prevented the growth of ice. Hence, a guideline for the selection of ice nucleus material was obtained. 相似文献
922.
Yoshiko Yamazaki Toru Matsunaga Aya Ichinokawa Yoko Fujishiro Emi Saito Takao Sato 《应用聚合物科学杂志》2009,114(5):2764-2768
In the zwitterionic polymer gel which has cationic and anionic groups inside, it forms a complex to producing stability by adding thermal energy. We reported the behavior induced by the ionic interaction of them and the impact that a nonionic surfactant could exert on the complex formation. We had heating experiments of the zwitterionic polymer gel in PBS with a nonionic surfactant added. We analyzed DSC and measured the diameter, stress and flexure of heated the gel. As the result, it has been demonstrated that formation of strong ionic interactions inside the gel can be achieved by heating them in a solution containing the nonionic surfactant. It has been also demonstrated that the ratio of bound water is increased within the gel, promising an enhanced strength. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
923.
A three-port, 450 mum tall, monolithic rectangular coaxial power divider is introduced. The device is fabricated by a surface micromachining process with six sequentially deposited copper layers with thicknesses of 50 and 100 mum. The divider has an overall loss of 0.2 dB at 30 GHz, the input port return loss is better than 10 dB and the output amplitude and phase misbalances are plusmn0.35 dB and plusmn2.2deg, respectively, from 20 to 40 GHz. The device is designed in a way that permits straightforward realisation of a Wilkinson divider with integrated resistor. 相似文献
924.
Lukic M.V. Filipovic D.S. Fontaine D. Rollin J.-M. Saito Y. 《Antennas and Propagation, IEEE Transactions on》2009,57(9):2583-2590
A Ka-band monolithically integrated 4 times 1 corporate-fed cavity-backed patch antenna array is demonstrated in this paper. A single antenna element has four slits introduced to extend the bandwidth to about 8%. Its gain and radiation efficiency are 6.3 dBi and 97%, respectively. A rectangular mu-coaxial line based combining network is monolithically integrated with radiating elements in a slightly modified tile configuration. Specifically, to reduce the array footprint power dividers are aligned along the array axis. Combining network has height 1/2 that of the array and feed lines do not route through the antenna elements. Overall loss of the combining network is 0.5 dB at 30 GHz. Measured reflection coefficient bandwidth and maximum gain of the fabricated 4 times 1 corporate-fed array are 13.7% and 12.73 dBi, respectively. The array is designed and fabricated in a recently developed surface micromachining process known as PolyStrata. 相似文献
925.
Shigeo Nagaya Naoki Hirano Toshio Katagiri Tsutomu Tamada Koji Shikimachi Yu Iwatani Fusao Saito Yusuke Ishii 《低温学》2012,52(12):708-712
Development of apparatuses for protecting industrial facilities such as semiconductor plants or information industries from instantaneous voltage dips, which requires very large output power, has been expected. A Superconducting magnetic energy storage system (SMES), one of such apparatus, consists of superconducting magnets that must withstand high voltage during operation and require high reliability. We have already development of SMES using conventional superconducting coils and done the field test of the SMES for bridging instantaneous voltage dips. After field test, the commercial SMES for instantaneous voltage dips is working there. Since field test has started, we have confirmed nearly 40 operations, and all have succeeded. In 2011, three commercial SMES units for bridging instantaneous voltage dips are operating in Japan. 相似文献
926.
Toshiya KamadaYuji Sutou Masashi SumiyaYuta Saito Junichi Koike 《Thin solid films》2012,520(13):4389-4393
Phase change random access memory (PCRAM) requires an advanced phase change material to lower its power consumption and to enhance its data retention and endurance abilities. The present work investigated the crystallization behaviors and electrical properties of Ge1Cu2Te3 compound films with a low melting point of about 500 °C for PCRAM application. Sputter-deposited Ge1Cu2Te3 amorphous films showed a high crystallization temperature of about 250 °C. The Ge1Cu2Te3 amorphous film showed an electrical resistance decrease of over 102-fold and exhibited a small increase in thickness of 2.0% upon crystallization. The Ge1Cu2Te3 memory devices showed reversible switching behaviors and exhibited a 10% lower power consumption for the reset operation than the conventional Ge2Sb2Te5 memory devices. Therefore, the Ge1Cu2Te3 compound is a promising phase change material for PCRAM application. 相似文献
927.
Investigation of wall stress development and packing ratio distribution in the metal hydride reactor
Masahiko Okumura Koki Terui Ayaka Ikado Yasuhiro Saito Masakazu Shoji Yohsuke Matsushita Hideyuki Aoki Takatoshi Miura Yoshiaki Kawakami 《International Journal of Hydrogen Energy》2012
The strains generated in a reaction vessel of hydrogen storage alloys and the packing ratio distribution inside the vessel were measured in order to analyze the effects of packing on stress. More specifically strains generated on the vessel’s surface were measured when hydrogen is repeatedly absorbed and desorbed by the packed bed in the reaction vessel. The amount of deformation, local packing ratios and relative particle volumes in the vessel were also measured after repeated hydrogen absorption–desorption. As absorption–desorption was performed repeatedly, agglomeration regions where the value of the local packing ratio was around 0.6 were formed, and particularly strong stress was generated in these regions, causing deformation. More hydrogen packing causes agglomeration regions to form over a wider area. Since alloys are pulverized by repeated absorption–desorption, and concentrate in the lower parts of the vessel, agglomeration regions are also formed in the lower parts. Our experiments also revealed that the resulting agglomeration regions have a packing ratio of about 0.6. 相似文献
928.
929.
Togashi K Iizuka T Kato N Sasaki T Mukai Y 《Journal of nanoscience and nanotechnology》2012,12(1):568-572
To introduce self-organization ability of transmembrane proteins into Langmuir (L) and Langmuir-Blodgett (LB) techniques, we focused on "amphiphilic peptide" (AP) which is composed of two distinct hydrophilic and hydrophobic domains. Three types of APs of different average hydropathies were used to prepare the AP/lipid mixed L and LB films. According to the circular dichroism spectra, the secondary structures of APs were not uniform but were a mixture of alpha-helix, beta-strand and random coil. The fraction of alpha-helix was higher for lower hydropathy AP. The interaction between AP and lipid in the L film and the structure of the LB film were also depended on the APs used. 相似文献
930.
Young-Soon Jung Wataru Nakao Koji Takahashi Kotoji Ando Shinji Saito 《Journal of the American Ceramic Society》2009,92(1):167-173
The crack-healing behavior of machining cracks in a Si3 N4 /SiC composite containing Y2 O3 and Al2 O3 as a sintering additive was investigated. The machining cracks were introduced by a wheel grinding process, which is the most common method for finishing ceramic components. A semicircular groove was made at the center of small bending specimens by the machining. The machined specimens were healed at various temperatures and times in air. The optimized crack-healing condition of the machined specimen was found to be a temperature of 1300°C and a time of 1 h. The specimens healed by this condition exhibited almost the same strength as the smooth specimens that underwent the healing process. Moreover, the bending strength and fatigue limit of the machined and healed specimens were systematically investigated at temperatures ranging from room temperature to 1300°C. The heat-resistance temperature has been determined to be approximately 1000°C. Also, the specimens exhibited high static and cyclic fatigue limits at temperatures of 800° and 1000°C. These results demonstrate that crack healing could be an effective method for improving the structural integrity and reducing the manufacturing costs of a Si3 N4 /SiC composite ceramic. 相似文献