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排序方式: 共有1222条查询结果,搜索用时 15 毫秒
141.
Hong W.-P. Bhat R. DeRosa F. Hayes J.R. Chang G.-K. 《Electron Device Letters, IEEE》1991,12(6):284-286
The transport properties and device characteristics of pseudomorphic In0.4Al0.6As/InP modulation-doped heterostructures are investigated. The existence of a two-dimensional electron gas at the heterojunction was confirmed by Shubnikov-de Haas measurements. A high electron mobility transistor (HEMT) having a gate length of 1.5 μm showed extrinsic transconductances and drain current densities as high as 160 mS/mm and 300 mA/mm, respectively. The HEMT also showed a very small output conductance of less than 2 mS/mm and high gate-drain breakdown voltage of larger than 15 V. These results show the great potential of this HEMT for high-voltage gain and high-power microwave applications 相似文献
142.
Hong W.P. Bhat R. Nguyen C. Koza M. Caneau C. Chang G.K. 《Electron Devices, IEEE Transactions on》1992,39(12):2817-2818
The authors report the first demonstration of In0.52Al 0.48As/In0.53Ga0.47As metal-semiconductor-metal (MSM) photodetectors and high-electron-mobility transistors (HEMTs) grown on GaAs substrates by organometallic chemical vapor deposition. Both photodetectors and transistors showed no degradation in performance compared to devices simultaneously grown on InP substrates. The photodetectors exhibited a responsivity of 0.45 A/W and leakage current of 10 to 50 nA. The HEMTs with a gate length of 1.0 μm showed a transconductance as high as 250 mS/mm, and f T and f max of 25 and 70 GHz, respectively 相似文献
143.
Zah C.E. Delfyett P.J. Bhat R. Caneau C. Favire F. Pathak B. Lin P.S.D. Gozdz A.S. Andreadakis N.C. Koza M.A. Iqbal M.Z. Izadpanah H. Lee T.P. 《Electronics letters》1993,29(10):857-859
1.5 mu m compressive-strained multiquantum-well gain-coupled distributed-feedback lasers have been fabricated on semi-insulating InP substrates with very low parasitic capacitance for studying the laser dynamic characteristics. A maximum 3 dB bandwidth of 12.8 GHz under small signal modulation, a 20 dB down chirping width of 0.33 nm under modulation, a 20 dB down chirping width of 0.33 nm under 5 Gbit/s NRZ pseudorandom modulation, and a low chirping short pulse of 20 ps under gain switching are obtained.<> 相似文献
144.
A high-frequency link series-parallel resonant power converter is analyzed using the state-space approach. Analysis is presented for both the continuous capacitor voltage mode and the discontinuous capacitor voltage mode. Steady-state solutions are derived. Design curves for the converter gain and other component stresses are obtained. A method of optimizing the converter under certain constraints is presented and a simple design procedure is illustrated by a design example. Experimental results are presented to verify the theory 相似文献
145.
A decision-theoretic approach is proposed for bad-data elimination in parameter estimation. A linear measurement model with unknown additive noise having zero mean is considered and the noise distribution is assumed to be symmetrical and absolutely continuous. The partial covariance of the measurement random variable is considered to be constrained, and its minimum covariance and unbiasedness are chosen as criteria of goodness for the estimator. Using game-theory, a soft-limiter is shown to be optimal. It is also established that in the presence of bad data, performance of the proposed scheme is superior, and in its absence comparable, to that of linear estimators. 相似文献
146.
B. V. Radhakrishna Bhat Y. R. Mahajan H. Md. Roshan YVRK Prasad 《Metallurgical and Materials Transactions A》1992,23(8):2223-2230
The constitutive flow behavior of a metal matrix composite (MMC) with 2124 aluminum containing 20 vol pct silicon carbide
particulates under hot-working conditions in the temperature range of 300 °C to 550 °C and strain-rate range of 0.001 to 1
s-1 has been studied using hot compression testing. Processing maps depicting the variation of the efficiency of power dissipation
given by [2m/(m + 1)] (wherem is the strain-rate sensitivity of flow stress) with temperature and strain rate have been established for the MMC as well
as for the matrix material. The maps have been interpreted on the basis of the Dynamic Materials Model (DMM). [3] The MMC
exhibited a domain of superplasticity in the temperature range of 450 °C to 550 °C and at strain rates less than 0.1 s-1. At 500 °C and 1 s-1 strain rate, the MMC undergoes dynamic recrystallization (DRX), resulting in a reconstitution of microstructure. In comparison
with the map for the matrix material, the DRX domain occurred at a strain rate higher by three orders of magnitude. At temperatures
lower than 400 °C, the MMC exhibited dynamic recovery, while at 550 °C and 1 s-1, cracking occurred at the prior particle boundaries (representing surfaces of the initial powder particles). The optimum
temperature and strain-rate combination for billet conditioning of the MMC is 500 °C and 1 s-1, while secondary metalworking may be done in the super- plasticity domain. The MMC undergoes microstructural instability
at temperatures lower than 400 °C and strain rates higher than 0.1 s-1. 相似文献
147.
148.
A hydromagnetic inclined porous slider bearing with a transverse magnetic field is analysed. Expressions for various bearing characteristics are obtained for large and small Hartmann numbers. The dimensionless load capacity, friction and centre of pressure are computed for large Hartmann numbers in the open-circuit case; the load capacity and friction increase markedly with increasing Hartmann number. 相似文献
149.
Orbital information forAryabhata was computed and made available for telemetry and tracking schedules and for mission analysis. Taking an available statevector
once in a week from USSR, the orbital computations were made for the first four months using a numerical integration procedure.
During the later period of the mission, an analytical method was adopted to reduce the computer time.Aryabhata, in a near circular orbit at 600 km and having an inclination of 50.68°, experienced a constant atmospheric drag due to which
the semi-major axis decayed by about 0.5 km in one year. The nodal regression rate, due to asphericity of the earth, was almost
constant at 4.632°/day. The inclination remained constant throughout the year. 相似文献
150.
Spectral domain analysis is used to determine the end effects in coupled rectangular slot resonators in unilateral fin lines. End corrections computed as a function of the structural parameters are reported. 相似文献