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71.
Obayashi S. Tsukahara T. Nakamura T. 《Industrial Electronics, IEEE Transactions on》2000,47(1):211-216
A multiobjective genetic algorithm (GA) based on Fonseca-Fleming's Pareto-based ranking and fitness-sharing techniques has been applied to aerodynamic shape optimization of cascade airfoil design. Airfoil performance is evaluated by a Navier-Stokes code. Evaluation of GA population is parallelized on the Numerical Wind Tunnel, a parallel vector machine. The present multiobjective design seeks high pressure rise, high flow turning angle, and low total pressure loss at a low Mach number. Pareto solutions that perform better than existing control diffusion airfoils were obtained 相似文献
72.
Ueno Y. Takahashi M. Nakamura S. Suzuki K. Shimizu T. Furukawa A. Tamanuki T. Mori K. Ae S. Sasaki T. Tajima K. 《Photonics Technology Letters, IEEE》2002,14(12):1692-1694
A control scheme for accurately optimizing (and also automatically stabilizing) the interferometer phase bias of symmetric-Mach-Zehnder (SMZ)-type ultrafast all-optical switches is proposed. In this control scheme, weak continuous-wave light is used as supervisory input light and its spectral power ratio at the switch output is used as a bipolar error signal. Our experimental results for 168-Gb/s 16:1 demultiplexing with a hybrid-integrated SMZ switch indicate the feasibility and the sensitivity of this control scheme. 相似文献
73.
Sekiguchi T. Itoh K. Takahashi T. Sugaya M. Fujisawa H. Nakamura M. Kajigaya K. Kimura K. 《Solid-State Circuits, IEEE Journal of》2002,37(4):487-498
The noise-generating mechanisms inherent in the open-bitline DRAM array using the 6F2 (F: feature size) memory cells and techniques for reducing the noise are described. The sources of differential noise coupled to the paired bitlines laid out in two arrays are the p-well, cell plate, and the group of nonselected wordlines. It was found, by simulation and by experiment with a 0.13-μm 256-Mb test chip, that the level of noise is dramatically reduced by using a low-impedance array with careful layout featuring low-resistivity materials, tight bridging between pairs of adjacent arrays, and a small array, achieving a comparable level of noise to that seen in the twisted and folded-bitline array. On basis of these results, it turns out that the open-bitline array has a strong chance of revival in the multigigabit generation, as long as these noise reduction techniques are applied 相似文献
74.
Takeshi Yanagisawa Takeshi Kojima Tadamasa Koyanagi Kiyoshi Takahisa Kuniomi Nakamura 《Microelectronics Reliability》2002,42(2):219-223
Changes in the characteristics of CuInGaSe2 solar cells in response to light irradiation were investigated. Then these changes, which suggest long-term degradation, were clarified using the measurement technique by feeble light. The thin-film cell of this type is considered to be “ever stable”. A stable result over the short term was also obtained in the light accelerated test of 2-SUN performed in this experiment. On the other hand, it was found that the characteristics measured with feeble light show a remarkable change over time. As a result of measuring at 0.065–105 mW/cm2 light intensity, the change rate of cell output power was so intense the measurement light was weak. This finding reflects the increase in an internal defect and suggests a possibility that light irradiation exerts the influence on long-term cell performance. Moreover, by measuring with feeble light, we found that the changed output recovers by reverse voltage application. The phenomenon of recovery up on comparatively low reverse voltage can be considered as an application for maintaining stability. 相似文献
75.
Hisashi Masui Samantha C. Cruz Shuji Nakamura Steven P. DenBaars 《Journal of Electronic Materials》2009,38(6):756-760
Inclined crystallographic planes of the wurtzite structure were investigated in comparison with the zincblende structure in
terms of surface geometry characteristics. The ball–stick model indicates that the semipolar surface possesses a surface polarity resembling the anion polarity, which agrees with the common experimental observations
of epitaxial growth preference for the cation-polarity surface over the surface. The wurtzite surface was found to share geometrical similarities with the zincblende {100} surface uniquely among the possible semipolar
planes. This finding encourages epitaxial growth on the plane of wurtzite semiconductors, e.g., GaN, with the potential of avoiding atomic step formations typically associated with
off-axis crystallographic planes. 相似文献
76.
Thiamine pyrophosphatase activity in the Golgi apparatus of calcitonin-treated osteoclasts. 总被引:1,自引:0,他引:1
The thiamine pyrophosphatase (TPPase) activity described by Novikoff and Goldfisher was examined in osteoclasts affected by calcitonin in order to elucidate whether the morphological and functional changes of the osteoclasts have an influence over the secretion function of their Golgi apparatus. The Golgi apparatus of osteoclasts of which the ruffled border had disappeared and bone resorption discontinued as the result of treatment with calcitonin showed a slight TPPase activity. The reaction products of the enzyme in these inactive osteoclasts were distinctly fewer than that of control osteoclasts, which were not affected by calcitonin. From these results, it is suggested that there may be a connection between the morphological and functional changes of osteoclasts and the secretion function of the Golgi apparatus. 相似文献
77.
N. Takahashi K. Terada T. Takahashi T. Nakamura W. Inami Y. Kawata 《Journal of Electronic Materials》2003,32(4):268-271
Optical response of tin nitride (SnNx) films, which were deposited onto quartz substrates by means of atmospheric pressure, halide chemical vapor deposition (AP-HCVD),
were examined by pulsed irradiation of a YAG laser (532 nm). It was observed that the transmittance of a light of a He-Ne
laser (633 nm) through the SnNx film decreases after the film is irradiated with a YAG laser. The atomic force microscopy (AFM) micrograph observation confirmed
that spot-like humps appeared on the SnNx film surface in the regions spotted by the YAG laser. This phenomenon was explained in terms of the laser-assisted thermal
decomposition of SnNx to β-tin. 相似文献
78.
Arahira S. Takahashi H. Nakamura K. Yaegashi H. Ogawa Y. 《Quantum Electronics, IEEE Journal of》2009,45(5):476-487
We proposed and demonstrated all-optical clock recovery system using a monolithic mode-locked laser diode (MLLD) that operated with less sensitivity to the polarization and the wavelength of the input data signals also with no bandpass filter to eliminate the input signal-components. The keys to this new technique are the MLLD integrated with a tensile-strained quantum-well saturable absorber and a new polarization-diversity setup by signal input orthogonally polarized to the lasing polarization of the MLLD. This approach was experimentally validated in the 40 Gbps clock recovery experiments. The results exhibited excellent performance of the clock recovery with low timing jitters (<0.3 ps) remaining small dependence on the wavelength and the polarization of the input data signals and input-signal suppression less than -30 dB with no use of the bandpass filter. We also succeeded in the stable clock recovery for the input of polarization-scrambled data signals. 相似文献
79.
Tomioka T. Nakamura M.S. Furuyama H. Onomura M. Ohshima S. 《Electronics letters》1992,28(19):1788-1790
A new heterodyne receiver is demonstrated. The local laser diode (LD) was built-in and no fibre was used between the parts. The number of optical parts and assembly processes was reduced, and a better performance was achieved because there was no polarisation fluctuation of the local light. The effect of a mismatch in the beam profile is discussed.<> 相似文献
80.