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111.
As the atmospheric electric field always fluctuates, its observed waveforms are very complicated. It is important to detect the characteristic variation from the observed signals and determine its cause. The natural observation method is adequate for analyzing such nonperiodic signals as the atmospheric electric field signals. In this method the aspectum is proposed as the quantity to estimate the instantaneous power. In this study signal processing by the aspectum was applied to signals of atmospheric electric field variation. It was clarified that a strong correlation exists between the instantaneous fluctuations of atmospheric electric field and the wind speed in the convenient meteorological environment. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 27–34, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20302 相似文献
112.
Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO. 总被引:27,自引:0,他引:27
Atsushi Tsukazaki Akira Ohtomo Takeyoshi Onuma Makoto Ohtani Takayuki Makino Masatomo Sumiya Keita Ohtani Shigefusa F Chichibu Syunrou Fuke Yusaburou Segawa Hideo Ohno Hideomi Koinuma Masashi Kawasaki 《Nature materials》2005,4(1):42-46
Since the successful demonstration of a blue light-emitting diode (LED), potential materials for making short-wavelength LEDs and diode lasers have been attracting increasing interest as the demands for display, illumination and information storage grow. Zinc oxide has substantial advantages including large exciton binding energy, as demonstrated by efficient excitonic lasing on optical excitation. Several groups have postulated the use of p-type ZnO doped with nitrogen, arsenic or phosphorus, and even p-n junctions. However, the choice of dopant and growth technique remains controversial and the reliability of p-type ZnO is still under debate. If ZnO is ever to produce long-lasting and robust devices, the quality of epitaxial layers has to be improved as has been the protocol in other compound semiconductors. Here we report high-quality undoped films with electron mobility exceeding that in the bulk. We have used a new technique to fabricate p-type ZnO reproducibly. Violet electroluminescence from homostructural p-i-n junctions is demonstrated at room-temperature. 相似文献
113.
Kenji Wada Kazuhiko Hirabayashi Naoki Watanabe Shingo Yamamoto Teruyuki Kondo Take-aki Mitsudo Masashi Inoue 《Topics in Catalysis》2009,52(6-7):693-698
Novel Ti-containing silsesquioxane gel catalysts were prepared by the hydrosilylative condensation of Ti-containing silsesquioxanes together with cubic silsesquioxanes and spherosilicates. The porosity of gels was controlled by changing the composition and the mixing order of the starting materials. Both porous and nonporous gels were found to act as excellent heterogeneous catalysts towards the selective epoxidation of cyclooctene by the use of aqueous hydrogen peroxide as an oxidant. 相似文献
114.
115.
Rahmat Budiarto Masashi Yamada Hidenori Itoh Hirohisa Seki 《Computers & Industrial Engineering》1996,31(3-4):939-943
In many method of the cat's cradle string diagram processing in use today, there is no a strong emphasis on user interaction. This paper discusses a method for constructing cat's cradle string diagram in 2-D. The method uses a string representation and processing in 2-D which preserves the topology characteristics of the string diagram and also uses a small data volume. The inputted string diagram is transformed onto its cat's cradle string diagram by geometric transformation and GA. The method allows the user to interactively construct a cat's cradle string diagram. Three operations are used for constructing cat's cradle diagram, they are pull (over and under), release and exchange. An implemented program executed some shapes of cat's cradle for verifying the method. 相似文献
116.
The basic characteristics of secondary electron emission (SEE) from various organic compounds have been investigated, and a channel electron multiplier with high gain and flexibility has been developed. The maximum SEE yield is higher for the aliphatic compound than for the aromatic, and is higher for the organic solid with high ionization potential. By studying the SEE yields from the electron-conductive polymeric compositions which consist of plasticized poly(vinyl chloride) and electroconductive particles (NaTCNQ or carbon black), it is shown that the SEE yield depends mainly on the characteristics of the matrix polymer and is almost independent of the addition of electroconductive particles which inherently have low SEE yields. Adding less than 5% stabilizers to these polymeric compositions has little effect on the SEE yields. A flexible channel electron multiplier (FCEM) made of the electron-conductive polymeric composition shows the following characteristics: gain ? 108 (applied voltage of 3 kV); rise time ? a few nanoseconds; background count rate < 0.1 cps; and maximum output current ? 10?6 A. As a photon detector in the vacuum UV region, the FCEM shows a threshold value of 8.4 eV for photoelectric emission. 相似文献
117.
Gd(x)Y(1-x)Ca4O(BO3)3 (GdYCOB) is a promising nonlinear optical crystal that shows high effective nonlinearity d(eff), noncritical phase matching, and high chemical stability. We report on the fabrication and characteristics of a monolithic wavelength converter, which generates ultraviolet light by the incidence of a 1.064 microm near-infrared laser. The converter consists of GdYCOB for third-harmonic generation, KTiOPO4 (KTP) for second-harmonic generation, and a wave plate. GdYCOB has the advantage of an extremely wide angular acceptance bandwidth, whereas KTP exhibits a high effective nonlinear coefficient and a broad temperature bandwidth. Consequently the combination of these crystals results in highly efficient and stable ultraviolet conversion for constructing a compact and robust ultraviolet laser. 相似文献
118.
Saburo Hosokawa Yukihiro Hayashi Seiichiro Imamura Kenji Wada Masashi Inoue 《Catalysis Letters》2009,129(3-4):394-399
Ceria colloidal particles with a mean crystallite size of 2 nm were synthesized by a solvothermal reaction. The Ru/CeO2 catalyst prepared from the CeO2 colloids exhibited higher activity than the catalyst prepared from Ce(NO3)3. Temperature-programmed reduction analysis indicated that the reduction of surface Ce4+ was accelerated by highly dispersed Ru species on the CeO2 particles and occurred at low temperatures. The single component CeO2 sample prepared by the coagulation of the CeO2 colloid was more easily reduced and re-oxidized than the CeO2 sample prepared by the precipitation method from Ce(NO3)3. The higher activity of Ru/CeO2 prepared from the CeO2 colloids came from the inherent nature of the CeO2 support itself. 相似文献
119.
The effects of cobalt addition on the sintering, thermal, and electrical properties of Ce0.9Gd0.1O1.95 (GDC) and Zr0.89Sc0.1Ce0.01O2−δ (ScSZ) were investigated. A small addition of cobalt oxide remarkably enhanced the sinterability of GDC, especially for GDC powder with a specific surface area of 40 m2 g−1, which was synthesized via a citrate method. Relative densities of approximately 95% can be achieved for GDC pellet samples using 2 mol% Co dopant and sintering at 1100 °C for 10 h. The thermal expansion and electrical conductivity of 2 mol% Co-doped GDC were comparable to those of the non-doped sample. The thermal expansion of ScSZ with various amounts of Co addition was linear in both oxidizing and reducing atmospheres. The electrical conductivity of Co-doped ScSZ decreased with increasing Co content; however, this decrease was not dramatic. These results suggest that the addition of cobalt oxide is a promising method for obtaining GDC buffer layers that are sinterable at low temperatures for use in intermediate temperature-solid oxide fuel cells. 相似文献
120.
Masashi Kato Tomonari Yasuda Keiko Miyake Masaya Ichimura Tomoaki Hatayama 《International Journal of Hydrogen Energy》2014
Solar-to-hydrogen conversion efficiencies of water-splitting photochathodes using epitaxially grown p-type 4H-, 6H- and 3C-SiC were estimated in a two-electrode system without applying any external bias. By using electrode materials with small oxygen overpotentials as counter electrodes, the photocurrent became comparable to that observed in a three-electrode system with a suitable bias. Estimated efficiencies seem to depend on the bandgap of the SiC polytypes. For the 3C-SiC, the obtained efficiency was 0.38%, which is so far the highest value reported for SiC. We confirmed that the hydrogen volumes estimated from the photocurrent were almost the same as actual volumes observed by gas chromatography. 相似文献