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排序方式: 共有534条查询结果,搜索用时 171 毫秒
91.
Yasuhiro Suzuki Yuichi Tohmori Kazutoshi Kato Mitsuo Fukuda Hiromi Oohashi Satoshi Sekine Naoto Uchida Hiromu Toba Masaharu Horiguchi Toshihiko Sugie Yasuhumi Yamada 《Optical and Quantum Electronics》1998,30(3):141-159
Cost-effectiveness is essential in developing optical access network systems. To reduce system costs, both improved system and component technologies are required. Reducing the costs of optical devices and modules in an optical network unit is especially necessary. In this paper, the requirements for optical devices in optical access networks and modules are clarified. Moreover, we also review the recent progress in technologies for semiconductor optical devices and hybrid integration for low-cost optical modules in access networks. 相似文献
92.
S. Aoyama 《Zeitschrift fur Physik C Particles and Fields》1989,42(2):297-300
TheB-C system with an arbitrary conformal weight by Friedan, Martinec and Shenker is formulated by using the Beltrami parametrization. The holomorphic factorization will be manifest. We quantize the system in the BRST formalism. It will be shown by an explicit calculation that the Slavnov-Taylor identity is afflicted by the holomorphic anomaly. 相似文献
93.
M. B. Smirnov I. Yu. Skobelev A. I. Magunov A. Ya. Faenov T. A. Pikuz Y. Fukuda K. Yamakawa Y. Akahane M. Aoyama N. Inoue H. Ueda 《Journal of Experimental and Theoretical Physics》2004,98(6):1123-1132
Interaction between high-power ultrashort laser pulse and giant clusters (microdroplets) consisting of 109 to 1010 atoms is considered. The microdroplet size is comparable to the laser wavelength. A model of the evolution of a microdroplet plasma induced by a high-power laser pulse is developed, and the processes taking place after interaction with the pulse are analyzed. It is shown theoretically that the plasma is superheated: its temperature is approximately equal to the ionization potential of an ion having a typical charge. The microdroplet plasma parameters are independent of the pulse shape and duration. The theoretical conclusions are supported by experimental studies of x-ray spectra conducted at JAERI, where a 100-terawatt Ti-sapphire laser system was used to irradiate krypton and xenon microdroplets by laser pulses with pulse widths of 30 to 500 fs and intensities of 6×1016 to 2×1019W/cm2. 相似文献
94.
Hiromu Saito Motoshi Matsuura Takashi Inoue 《Journal of Polymer Science.Polymer Physics》1991,29(12):1541-1546
Depolarized light scattering measurements on single-phase mixtures of dissimilar polymers, poly(methyl methacrylate) (PMMA)/poly (acrylonitrile-co-styrene) (SAN, AN content = 15 wt %) and PMMA/poly (vinylidene fluoride) (PVDF) were carried out. The effective mean-square optical anisotropy γ2 of the mixtures was found to be much higher than that estimated by the simple additivity of γ2 of component polymers. From the deviation, the order parameter (1 + J12) was estimated to be in a range of 2–13, depending on the blend composition. This suggests local ordering in the single-phase mixtures, i.e., nematic alignment of the locally stretched dissimilar chains. In contrast, the deviation was slight in the polymer/solvent systems, SAN/MMA (monomer) and PVDF/butanone. The degree of ordering decreased with increasing temperature. T. The Specific interaction evidenced by FTIR spectroscopy exhibited a similar temperature dependence. Thus, local ordering seems to be induced by specific interactions and chain connectivity. The temperature dependence of J12 was successfully described by the Landau-de Gennes theory; J ∞ (T + T0)/ T, T0 being the isotropic-nematic transition temperature, as in the case of liquid crystals. 相似文献
95.
Total Synthesis and Biological Evaluation of the Glycosylated Macrocyclic Antibiotic Mangrolide A 下载免费PDF全文
Hiromu Hattori Joel Roesslein Dr. Patrick Caspers Dr. Katja Zerbe Dr. Hideki Miyatake‐Ondozabal Dr. Daniel Ritz Dr. Georg Rueedi Prof. Dr. Karl Gademann 《Angewandte Chemie (International ed. in English)》2018,57(34):11020-11024
The macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram‐negative pathogens. Reported is the first enantioselective total synthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two β‐selective glycosylations. The synthesis of mangrolide A and its analogues enabled the re‐examination of its activity against bacterial pathogens, and only minimal activity was observed. 相似文献
96.
Naoki Aoyama Tsukasa YoshiharaShin-ichi Furukawa Tomoshige NittaHideaki Takahashi Masayoshi Nakano 《Fluid Phase Equilibria》2007
Two types of molecular simulation techniques have been utilized to investigate adsorption of methanol/water mixtures in a mesoporous silica with a hydrophobic pore surface: the NVT-ensemble Molecular Dynamics method with the melt-quench algorithm for modeling a fully-silylated mesoporous silica and the μVT-ensemble Orientaional-Biased Monte Carlo method for calculating adsorption isotherms. Adsorption isotherms of methanol and water at 333 K are calculated for an equi-relative-pressure mixture (each component has the same relative pressure which is defined as the ratio of the partial pressure to the saturation pressure of the pure gas) together with pure gases. In the case of the pure gas, water hardly adsorb even at elevated pressures, while the adsorption isotherm for methanol shows the condensable adsorption. On the other hand, in the case of the mixture, water molecules are substantially adsorbed along with methanol molecules, showing an isotherm representing the condensation mechanism. In addition, it is found that the separation factor of methanol to water is the highest in the case of monolayer adsorption from a liquid mixture. 相似文献
97.
K. Hirose S. Takatani M. Aoyama 《Journal of Radioanalytical and Nuclear Chemistry》1994,182(2):349-358
To clarify environmental effects of the Chemobyl radionuclides, long-lived Chernobyl radioactivity (239,240Pu,238Pu,241Pu and90Sr) in deposition samples in May 1986 was measured at 11 stations in Japan. Temporal variation of weekly deposition of90Sr differed from that of volatile radionuclides such as131I and137Cs, which may reflect the released process at Chernobyl. On the other hand, the geographical distributions of the monthly deposition of long-lived radionuclides were similar to those of volatile radionuclides, in which maximum deposits of90Sr and plutonium were observed in Akita, a northwestern Japan Sea coast site of Honshu Island. Higher241Pu deposition in most of the stations, as well as high238Pu/239,240Pu activity ratios were observed. The241Pu/238Pu activity ratios in deposition samples were nearly equal to that in the total release, which is clear evidence that Chernobyl-derived plutonium was transported to Japan in May 1986 together with volatile radionuclides although the contribution of Chernobyl Pu was about three orders of magnitude lower than137Cs. 相似文献
98.
A catalyst comprised of Pd2(dba)3·CHCl3 and an N-Ar axially chiral mimetic-type ligand, (S)-N-[2-(diphenylphosphanyl)naphthalene-1-yl]-2-(piperidinylmethyl)piperidine, provides good enantioselectivities for the asymmetric Kumada-Corriu cross-coupling reaction of 1-phenylethylmagnesium chloride and E-β-bromostyrene derivatives with which it is more difficult to achieve high enantioselectivity. Furthermore, in the case of styrene derivatives bearing both vinyl and aryl bromide groups, the chemoselective asymmetric cross-coupling reaction of the vinyl bromide group is observed. This N-Ar axially chiral mimetic-type ligand allows easy synthesis of a wide variety of analogues, and starting from the initial ligand, the enantioselectivity of coupling products is improved by modifying the structure in the ligand. 相似文献
99.
Matsuura K Ariga K Endo K Aoyama Y Okahata Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(10):1750-1756
The inclusion behavior of gaseous guest molecules in a solid apohost, an orthogonal anthracene-bis(resorcinol)tetraol (1), was investigated with a quartz-crystal microbalance (QCM). Compound 1 forms crystals composed of molecular sheets bound together by an extensive hydrogen-bonded network. An apohost of 1 was cast onto a QCM and the binding of gaseous guest molecules was followed as a function of time by observing the decrease in the oscillation frequency, which is directly related to the increase in mass. Ethyl acetate and methyl ethyl ketone were significantly included into the apohost, whereas benzene and cyclohexane were simply adsorbed onto the surface of the solid; all these guests have similar vapor pressures at 25 degrees C. On the other hand, a host analogue 2, a tetramethoxy derivative of 1, barely included these guest molecules. The inclusion amount and the rate of inclusion of ethyl acetate or methyl ethyl ketone showed a drastic increase above a threshold concentration of guests in the gas phase. Thus, the structure of the apohost changed cooperatively in order to bind guest molecules above the threshold guest concentration. This cooperativity of the binding behavior was kinetically analyzed. 相似文献
100.
Thin-layer chromatography with flame ionization detection has been applied to the analysis of organic extracts of diesel exhaust particulates. Non-volatile organics whose boiling points are higher than ca. 300 degrees C can be analyzed, with a detection limit of ca. 0.03 micrograms and a relative standard deviation of ca. 10%. The organic extracts are separated into aliphatics , aromatics and polars by the development procedure with n-hexane, and the polars can be separated further by using toluene as the solvent. Some examples of application are presented. 相似文献