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101.
S. Kittaka K. Matsuno K. Tanaka Y. Kuroda M. Fukuhara 《Journal of Materials Science》2001,36(10):2511-2522
The interactions between vanadium pentoxide hydrate (V2O5·nH2O) sol and colloid solutions of ultra fine titanium dioxide TiO2 and zirconium dioxide particles ZrO2 were studied. When mixed with an intrinsic V2O5·nnH2O sol, TiO2 particles in the mixed sol are sandwiched by V2O5·nH2O layer sheets to form intercalation compounds. An Interlayer distance of V2O5·nH2O was increased by this treatment and the surface area was also increased from 7.9 m2 g–1 for the V2O5·nH2O to ca. 50 m2 g–1. When the TiO2 sol was contacted with K-type V2O5·nH2O, microporous nature appeared in the sample and the surface area incrased up to ca. 100 m2 g–1. The porous structure was maintained up to 300°C, above which materials were separated into two phases, anhydrous V2O5 and anatase type TiO2. Ultrafine ZrO2 particles were intercalated stoichiometrically in both intrinsic and K-type V2O5·nH2O giving ZrO2-V2O5·nH2O for all the mixing ratios from ZrO2/V2O5 = 5 to 20. Physico-chemical properties were almost unvaried and the materials were nonporous. Their surface areas are around 50 m2 g–1 for the former and around 60 m2 g–1 for the latter. The layered structure was maintained up to 300°C above which the sample was crystallized into ZrV2O7. The reaction temperature is about 150°C lower than that the heated mixture of ZrO2 and V2O5 powders. The electron microscope observations of the prepared materials showed that the number of the stacked layers was decreased from more than 10 sheets for the sample before intercalation to about 2–4 sheets by exfoliation. This indicates that V2O5·nH2O is exfoliated by ion exchangeably reacting to ultrafine titanium oxide and zirconium oxide particles. 相似文献
102.
This paper deals with a dynamic voltage restorer (DVR) characterized by installing the shunt converter at the load side. The DVR can compensate for the load voltage when a voltage sag appears in the supply voltage. An existing DVR requires a large capacitor bank or other energy‐storage elements such as double‐layer capacitors or batteries. The DVR presented in this paper requires only a small DC capacitor intended for smoothing the DC‐link voltage. Moreover, three control methods for the series converter are compared and discussed to reduce the series‐converter rating, paying attention to the zero‐sequence voltages included in the supply voltage and the compensating voltage. Experimental results obtained from a 200‐V, 5‐kW laboratory system are shown to verify the viability of the system configuration and the control methods. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(3): 73–82, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20460 相似文献
103.
STATEMENT OF PROBLEM: The surgical and restorative procedures at the posterior region of the maxilla and the mandible present a complex task in the treatment of partially edentulous patients. PURPOSE: The purpose of this study was to investigate the applicability of short hydroxylapatite-coated dental implants to the posterior mandible of partially edentulous patients. MATERIAL AND METHODS: Eight and 11 mm implants were evaluated as to their cumulative survival rate, clinical status (plaque index, gingival index, probing depth), and marginal bone loss over a 5-year period. RESULTS AND CONCLUSIONS: The verified overall cumulative survival rate was 94% for implants and 91% for prostheses. These results suggest predictable success for the application of short implants to the posterior mandible. 相似文献
104.
Saito M. Sugimori Y. Kohama Y. Yoshida Y. Miura N. Ishikuro H. Sakurai T. Kuroda T. 《Solid-State Circuits, IEEE Journal of》2010,45(1):134-141
An inductive-coupling programmable bus for NAND flash memory access in solid state drive (SSD) is presented. Compared to the conventional SSD, this wireless interface using relayed transmission reduces power consumption to 1/2, I/O circuit-layout area to 1/40, and achieves a data rate of 2 Gb/s in 0.18 ?m CMOS process. In addition, since this wireless interface enables one package to contain 64 chips, the number of packages is reduced to 1/8. 相似文献
105.
Hirofumi Matsuda Makoto Kuwabara Kohichi Hamamoto 《Journal of the American Ceramic Society》1998,81(1):229-232
Thin, semiconducting BaTiO3 ceramic wires prepared in the present study exhibited reversible stress-induced, nonlinear current—;voltage characteristics across several grain boundaries. A remarkable change in resistance with the application (by the three-point bending method) of only ∼1% tensile deformation indicated that the BaTiO3 wires may have potential as stress-sensing devices. Resistance in the BaTiO3 wires bot increased and decreased with increasing tensile stress parallel to the electric fields, far below the ferroelectric transition temperature, T c ; in Sr-substituted wires near T c , on the other hand, resistance only increased. Detailed studies of the patterns and fluctuation of polarization at grain boundaries could be meaningful, because stress-sensing characteristics may be induced by changes in the relative angle between polarization vectors of adjacent grains. 相似文献
106.
Chinone N. Kuroda T. Ohtoshi T. Takahashi T. Kajimura T. 《Quantum Electronics, IEEE Journal of》1985,21(8):1264-1270
Mode-hopping noise in index-guided semiconductor lasers is investigated. It is found that random switching between lasing modes and output power differences in those modes cause mode-hopping noise. An effective method to suppress such mode-hopping noise is proposed. High Te doping to an n-type GaAlAs cladding layer completely suppresses the noise. Te in GaAlAs forms a DX center that acts as a saturable absorber. This property stabilizes the laser mode and prevents mode competition. The minimum loss difference between lasing and nonlasing modes to suppress mode-hopping noise is also discussed. 相似文献
107.
Hirofumi Kakemoto Tohru Higuchi Hajime Shibata Satoshi Wada Takaaki Tsurumi 《Journal of Materials Science: Materials in Electronics》2008,19(4):311-314
The modification of thermoelectric figure of merit was estimated from enhanced mobility of [100] oriented beta-FeSi2 film. beta-FeSi2 on Si(001) substrate was prepared by molecular beam epitaxy method using an Fe source. The crystallographic orientation of
beta-FeSi2 film on Si(001) substrate was characterized by using X-ray diffraction. Using scanning electron microscopy, surface morphology
and film thickness of samples were observed and estimated, respectively. The mobility of beta-FeS2 film on Si(001) substrate were also characterized by Hall measurement at room temperature. A part of the enhancement of figure
of merit was evaluated as the functions of mobility and crystallographic orientation of samples. 相似文献
108.
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110.
This paper describes a bidirectional isolated DC/DC converter considered as a core circuit for next‐generation 3.3‐kV/6.6‐kV high‐power‐density power conversion systems. The DC/DC converter is intended to use power switching devices based on SiC and/or GaN, which will be available on the market in the near future. A 350‐V, 10‐kW, and 20‐kHz DC/DC converter is designed, constructed, and tested in this paper. It consists of two single‐phase full‐bridge converters with the latest trench‐gate Si‐IGBTs and a 20‐kHz transformer with a nano‐crystalline soft‐magnetic material core and litz wires. The transformer plays an essential role in achieving galvanic isolation between the two full‐bridge converters. The overall efficiency from the DC‐input to DC‐output terminals is accurately measured to be as high as 97%, excluding gate drive circuit and control circuit losses from the whole loss. Moreover, loss analysis is carried out to estimate effectiveness in using SiC‐based power switching devices. The loss analysis clarifies that the use of SiC‐based power devices may bring a significant reduction in conducting and switching losses to the DC/DC converter. As a result, the overall efficiency may reach 99% or higher. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 75–83, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20505 相似文献