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51.
Iwamuro N. Okamoto A. Tagami S. Motoyama H. 《Electron Devices, IEEE Transactions on》1991,38(2):303-309
The mechanisms of destructive failure of an insulated gate bipolar transistor (IGBT) at short-circuit state are discussed. Results from two-dimensional numerical simulation of p-channel and n-channel IGBTs are presented. It is found that there are two types of destructive failure mechanisms: a secondary breakdown and a latchup. Which type is dominant in p-channel and n-channel IGBTs depends on an absolute value of forward voltage |V CE|. At moderately low |V CE|, the p-channel IGBT is destroyed by secondary breakdown, and the n-channel IGBT, by latchup. This is due to the difference of a type of flowing carrier crossing a base-collector junction of wide base transistor and ionization rates of electrons and holes 相似文献
52.
H Okamoto 《Journal of Phase Equilibria and Diffusion》1992,13(1):107-108
53.
H Okamoto 《Journal of Phase Equilibria and Diffusion》1992,13(1):106-107
54.
An improved coupled-mode equation for nonlinear directional couplers (NLDC) with Kerr-like nonlinear media is proposed. The method is based on the generalized reciprocity relation in which two sets of field solutions satisfying Maxwell's equations are for the NLDC and for the isolated nonlinear waveguide. That leads to a reasonable result that all the coefficients in the coupled-mode equations, including the coupling coefficient, become power dependent. For the NLDC with a self-focusing or self-defocusing nonlinear material, the authors examine how the coupling coefficient, the coupling length, and the guided power depend on the input power in the range of coupling stronger than in previous reports. It is found that the critical power at which the coupling length becomes infinity does not increase as much with the two guides for the case of self-focusing media 相似文献
55.
H. Okamoto 《Journal of Phase Equilibria and Diffusion》1992,13(4):440-441
56.
H. Okamoto 《Journal of Phase Equilibria and Diffusion》1992,13(2):223-224
57.
58.
We report a dispersion slope equalizer on a planar lightwave circuit for wavelength division multiplexing (WDM) transmission. This device consists of an array of lattice-formed equalizers with different compensation values fabricated on one wafer and arrayed-waveguide gratings for wavelength multi/demultiplexing. We describe its configuration, operational principle, parameter design, fabrication, and measured characteristics in detail. N/spl times/20 and N/spl times/40 Gb/s slope equalizers were fabricated and their characteristics agreed well with designed values. We also report a reduction in the bias electrical power needed for thermooptic phase shifters in the equalizer array that we realized by employing a phase trimming technique normally used for optical switches. 相似文献
59.
60.
We observed change in distance between two droplets in each step after application of large multi-step shear strains. Experiments were performed using a sliding plate apparatus. Large step shear strains were applied to two polyisobutylene droplets in poly(dimethyl siloxane) matrix in the same plane between the plates. The distance between the two droplets decreases with increasing the total shear strain, which is given by the product of the step strain magnitude and the number of application of the step strains. The two droplets coalesce when the distance becomes less than the diameter of the droplets. The slope for plots of the distance versus the total strain is independent of the step strain magnitude. This indicates that the effect per unit strain on the distance is the same, irrespective of the strain magnitude. It is suggested that a stronger hydrodynamic interaction between the droplets is the main cause for the droplet approach. 相似文献