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排序方式: 共有266条查询结果,搜索用时 15 毫秒
261.
Masayuki Nakamura Hideaki Takagi Kiyoshi Einaga Toshiyuki Nishikawa Naoshi Moriyama Katsumi Wasaki 《IEEJ Transactions on Electrical and Electronic Engineering》2011,6(1):37-45
In installing wireless access systems for indoor use using IEEE 802.11b/g‐complied 2.4‐GHz band wireless local area network (LAN) units, problems that arise include blind zones and interferences caused by radio waves transmitted by neighboring access point units. To solve these problems, the use of leaky coaxial cables (LCXs) is a promising method. However, commercially available flexible LCXs with small diameters for 2.4‐GHz wireless LAN were not long enough for use in tunnels, underground facilities, and so on, and the communication characteristics of LCXs long enough for these places using wireless LAN units have not been reported. We have developed a flexible 300‐m long LCX for the 2.4‐GHz band and IEEE 802.11b/g‐complied wireless LAN units with high sensitivity. We evaluated its performance with four cable configurations and confirmed that this LCX provides wireless connections over 300 m along the cable and over 20 m lateral to the cable in an open‐air environment. We also found the coverage could be extended by a method of cable‐to‐cable links. IEEJ Trans 2010 DOI: 10.1002/tee.20604 相似文献
262.
Takayuki Harada Isao Ohkubo Mikk Lippmaa Yasuaki Sakurai Yuji Matsumoto Shunsuke Muto Hideomi Koinuma Masaharu Oshima 《Advanced functional materials》2012,22(21):4471-4475
A high‐performance spin filter tunnel junction composed of an epitaxial oxide heterostructure is reported. By independently controlling the magnetic orientations of ferromagnetic tunnel barrier and electrode layers, a tunnel magnetoresistance ratio exceeding 120% is obtained purely by the spin filtering effect. A newly introduced spin filter material, Pr0.8Ca0.2Mn1‐yCoyO3, is shown to be useful for building novel multibarrier spintronic tunnel devices due to its composition‐controlled magnetic hardness. 相似文献
263.
Kimata K Yamaguchi M Saito Y Hata H Miyake K Yamane T Nakagawa Y Yano A Ito K Kawarasaki Y 《Journal of Bioscience and Bioengineering》2012,113(2):154-159
Yeast's extracellular expression provides a cost-efficient means of producing industrially useful recombinant proteins. However, depending on the protein to be expressed, the production results in a poor yield, which is occasionally accompanied with loss of the expression plasmid and hence hampered growth of the host in the inducing medium. Here we propose an alternative approach, high cell-density expression, to improve the yield of a certain range of so-called difficult-to-express proteins. In this expression system, recombinant yeast cells resting in stationary phase (OD(660)=3-4) are suspended in a small aliquot of inducing medium to form a high cell-density culture (e.g., OD(660)=15). When applied to the yeast strains harboring Lentinula edodes laccase (Lcc1 or Lcc4) expressing plasmids, the high cell-density system allowed the host cells to synthesize elevated amounts of the laccase which resulted in >1000- to 6000-fold higher yield than those synthesized in a classical growth-associated manner. The resting cells required aerobic agitation for the maximum production. The production system also worked for other foreign enzymes but not for beta-galactosidase from Aspergillus oryzae or Escherichia coli, likely suggesting an involvement of chaperons that act on a certain range of secretory proteins. 相似文献
264.
Masaru Matsumoto Hisato Matsumiya Shinya Fujiwara Yasuaki Ito 《Journal of Wind Engineering & Industrial Aerodynamics》2010,98(8-9):429-437
This paper studies the coupled flutter mechanism of plate and long span bridges based on step-by-step analysis (SBS). Fundamental flutter modes are defined based on amplitude ratio and phase difference between heaving and torsional motions. Furthermore, a formula remarkably similar to the Selberg formula can be derived by use of the particular simplified flutter-onset condition. In the process of SBS analysis, some torsional divergent velocities where the torsional rigidity becomes zero can be defined. Finally, the flutter-behavior of an elastic model of the complete Akashi-Kaikyo Bridge, which is the longest suspension bridge in the world, is studied from the point of view of flutter in 2 degrees of freedom, namely heaving and torsional motion, taking into account the structural coupling effect of additional torsional displacement induced by horizontal displacement as a structural coupling property. 相似文献
265.
Taron Makaryan Yasuaki Okada Hiroyuki Kondo Seiji Kawasaki Keigo Suzuki 《Advanced functional materials》2023,33(2):2209538
Striving for the sixth-generation communication technology discovery, semiconductors beyond Si with wider bandgaps as well as non-conventional metals are actively being sought to achieve high speeds whilst maintaining devices miniaturization. 2D materials may provide the potential for downsizing, but their functional advantage over existing counterparts still longs to be discovered. Along that path, surface-adsorbed or bulk-intercalated water molecules remaining after wet-chemical synthesis of 2D materials are generally seen as obstacles to high-performance achievement. Herein, the control of such water within the interlayers of solution-processed metallic 2D titanium carbide (MXene) by vacuum annealing duration is demonstrated. Moreover, the impact of water removal on work function (WF) and functional terminations is unveiled for the first time. Furthermore, the usefulness of such water for controlling a novel Schottky diode in contact with an n-type oxide semiconductor, niobium-doped strontium titanate (Nb:SrTiO3) is observed. The advantage of MXene compared to conventional gold as facile processing, WF tunability, and lower turn-on voltage in the Schottky anode application is highlighted. This fundamental study shows the way for a novel Schottky diode preparation in atmospheric conditions and provides implications for further research directions aiming at commercialization. 相似文献
266.
The paper proposes a method to select a power factor for an inverter of distributed power generation systems to keep appropriate voltage of a power system with the high penetration of inverter-interfaced generation. The increase of inverter-interfaced power sources, such as wind and photovoltaic power generation, arouses concerns on the voltage fluctuations in a power system. While constant power factor control of an inverter has been studied as a means to stabilize the voltage of a power system, there still remains room to improve the control. The proposed method in the paper selects the power factor based on the R/X ratio of the looking-back impedance into the interconnected power system. By normalizing the related variables, a general formula is derived for the power factor, and the resultant relationship between the apparent power and voltage of an inverter becomes identical irrespective of the R/X ratio with the control. Sample studies show that, by operating an inverter with the power factor, voltage fluctuations are effectively suppressed even for a power system with the high penetration of inverter-interfaced generation. 相似文献