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61.
Oohashi H. Fukuda M. Kondo Y. Wada N. Tohmori Y. Sakai Y. Toba H. Itaya Y. 《Lightwave Technology, Journal of》1998,16(7):1302-1307
This paper discusses the degradation behaviors and reliability of spot-size converter integrated laser diodes fabricated using the full wafer process with dry etching and metal organic vapor phase epitaxy (MOVPE). Failure criteria applicable to actual access networks were determined based on the degradation behavior exhibited in several aging tests, and device lifetimes were then estimated. The far-field patterns and wide-temperature operation required for low-cost system application scarcely changed during degradation, even after a 150% increase in threshold current. Within this degradation range, the device life for system application is estimated to be more than 105 h at 60°C and 10 mW 相似文献
62.
Tohmori Y. Suzaki Y. Fukano H. Okamoto M. Sakai Y. Mitomi O. Matsumoto S. Yamamoto M. Fukuda M. Wada M. Itaya Y. Sugie T. 《Electronics letters》1995,31(13):1069-1070
A 1.3 μm laser has been developed with a butt-jointed selectively grown spot-sire converter (SSC). The SSC vertically tapered waveguide and strained multiquantum well (MQW) active region are independently optimised. The laser was buried with semi-insulating InP to reduce optical loss in the SSC. A threshold current of 7 mA and an output power of >20 mW were obtained. Minimum coupling loss to a flat-end fibre of 1.06 dB was achieved. Long-term stability was also confirmed 相似文献
63.
Diao YX Han MJ Wan LJ Itaya K Uchida T Miyake H Yamakata A Osawa M 《Langmuir : the ACS journal of surfaces and colloids》2006,22(8):3640-3646
The adsorption of 4,4'-bipyridine (BiPy) on Cu(111) has been investigated in 0.1 M HClO4 by cyclic voltammetry, electrochemical scanning tunneling microscopy (STM), and surface-enhanced infrared adsorption spectroscopy (SEIRAS). Cyclic voltammetry showed the double layer region extending from -0.2 to 0.26 V and a pair of redox waves superposing on hydrogen evolution wave at more negative potentials. Diprotonated BiPy, BiPyH2(2+), is adsorbed flat on the Cu(111) (1 x 1) surface and forms a well-ordered monolayer with a (3 x 4) symmetry in the double-layer potential region. At more negative potential, BiPyH2(2+) is reduced to its monocation radical, BiPyH2(*+), and forms another well-ordered structure in which the radicals are stacked in molecular rows with a face-to-face self-dimer as the building unit. The SEIRA spectra of both BiPyH2(2+) and BiPyH2(*+) are dominated by gerade modes which should be IR-inactive for the centrosymmetric species. The breakdown of the selection rule of IR absorption is ascribed to the vibronic coupling associated with charge transfer between BiPyH2(2+) and the surface and between the radicals. 相似文献
64.
K Ogawa M Nishii F Nohara T Saito T Itaya T Fujii 《Chemical & pharmaceutical bulletin》1992,40(3):612-616
A detailed account is given of the first chemical synthesis of hypoxanthine 7-N-oxide (5), which started from coupling of 6-chloro-5-nitro-4(3H)-pyrimidinone (7) with N-(4-methoxybenzyl)phenacylamine, generated in situ from the hydrochloride (8), and proceeded through cyclization of the resulting phenacylaminopyrimidinone (9) and removal of the 4-methoxybenzyl group. The results of catalytic hydrogenolysis, methylation followed by catalytic hydrogenolysis, and rearrangement under acidic conditions of 5 supported the correctness of the assigned structure. An ultraviolet spectroscopic approach suggested that the neutral species of 5 exists in H2O mainly as the N(7)-OH tautomer (21). In the in vitro bioassay of antileukemic activity against murine L5178Y cells, 5 was weakly cytotoxic, with IC50 of 100 micrograms/ml. It did not show any antimicrobial activity even at 1000 micrograms/ml. None of the 9-(4-methoxybenzyl) (11) and O-methyl (12, 13, and 14) derivatives was found to be antileukemic or antimicrobial. 相似文献
65.
Yoshimoto S Tsutsumi E Honda Y Murata Y Murata M Komatsu K Ito O Itaya K 《Angewandte Chemie (International ed. in English)》2004,43(23):3044-3047
66.
Itaya Y. Matsuoka T. Nakano Y. Suzuki Y. Kuroiwa K. Ikegami T. 《Electronics letters》1982,18(23):1006-1008
A new 1.5 ?m-wavelength GalnAsP/InP distributed feedback buried-heterostructure laser was fabricated by a three-step LPE growth process. The second-order corrugation grating was formed on the waveguide layer grown on the active layer. High differential quantum efficiency of 13%/facet was obtained. Single-longitudinal-mode operation in the temperature range from ?20°C to 55°C was obtained. 相似文献
67.
Itaya Y. Arai S. Kishino K. Asada M. Suematsu Y. 《Quantum Electronics, IEEE Journal of》1981,17(5):635-640
Reduction of the threshold current of GaInAsP lasers with an antimeltback layer was studied in the wavelength range1.50-1.65 mu n. The two-phase solution growth technique was applied using a relatively low temperature and a slow cooling rate of 0.17°C/min to reduce the active layer thickness. The antimeltback layer with a bandgap wavelength of 1.35 μm resulted in a flat active layer and eliminated the melt-back problem completely. From experiments and calculations we found that both the carrier and the optical confinement of this structure, having an antimeltback layer, were almost the same as those for the conventional InP cladding structure. A threshold eurrent density as low as 1.2 kA/cm2and an active layer thickness of 0.20μm were obtained at these wavelengths. The lattice-match condition of low-temperature growth was studied. In the low-temperature growth, the longer wavelength lasers were grown with the same amount of InAs.J_{th}/d was independent of the growth condition (T_{S}, T_{G} ) and had a value of 5-6 kA/cm2. μm. 相似文献
68.
The effectiveness of internal heating for enhancing the drying of molded ceramics is evaluated by both modeling and experiments.
In the theoretical analysis, three dimensional drying-induced strain–stress are modeled, and the numerical solutions show
that the internal heating generates lower internal stress than continuous convective heating or intermittent convective heating.
Microwave drying is examined experimentally to study the effect of internal heating on the drying behavior of a wet sample
of a kaolin slab. The drying behavior is compared among three modes: microwave heating, hot air heating and radiation heating.
The transient behavior of temperatures in microwave drying is quite different from conventional drying by external heating.
In particular, the temperature of the slab drops once in the progress of drying. This phenomenon cannot be predicted adequately
by a simple model of one-dimensional heat conduction and moisture diffusion accompanied with an internal heat generation rate
given as a linear function of the moisture content. It should be noted that the temperature behavior takes place due to the
combined interactions with internal evaporation of moisture by rise in internal vapor pressure and shift of impedance or interference
in the applicator. Microwave heating with a constant power above 100 W results in sample breakage due to the internal vapor
pressure. However, if the power is dynamically controlled so as to maintain the temperature less than the boiling point of
water, the drying succeeds without any crack generation until completion with a significantly faster drying rate than drying
in convective heating or in the oven. 相似文献
69.
Matsumoto M Inukai J Tsutsumi E Yoshimoto S Itaya K Ito O Fujiwara K Murata M Murata Y Komatsu K 《Langmuir : the ACS journal of surfaces and colloids》2004,20(4):1245-1250
Scanning tunneling microscopy (STM) and low-energy electron diffraction were used to reveal the structures of ordered adlayers of [2+2]-type C60-C60 fullerene dimer (C120) and C60-C70 cross-dimer (C130) formed on Au(111) by immersingit in abenzene solution containing C120 or C130 molecules. High-resolution STM images clearly showed the packing arrangements and the electronic structures of C120 and C130 on the Au(111) surface in ultrahigh vacuum. The (2 square root3 x 4square root3)R30 degrees, (2square root3 x 5square root3)R30 degrees, and (7 x 7) structures were found for the C120 adlayer on the Au(111) surface, whereas C130 molecules were closely packed on the surface. Each C60 or C70 monomer cage was discerned in the STM image of a C130 molecule. 相似文献
70.
T. Kinoshita H. Yamazaki H. Fukasawa K. Hirota T. Ishikawa J. Kasagi A. Kato T. Katsuyama K. Kino F. Miyahara T. Nakabayashi K. Nawa K. Okamura Y. Saitoh K. Satou M. Sengoku H. Shimizu K. Suzuki S. Suzuki T. Terasawa H. Kanda K. Maeda T. Takahashi Y. Aruga T. Fujinoya A. Iijima M. Itaya Y. Ito T. Iwata H. Kato T. Kawamura T. Michigami M. Moriya T. Sasaki Y. Tajima S. Takita T. Noma M. Yamamoto H.Y. Yoshida Y. Yoshida O. Konno T. Maruyama T. Yorita 《Physics letters. [Part B]》2006