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31.
32.
A new simplified threshold-voltage model for n-MOSFETs with nonuniformly doped substrate and its application to MOSFET's miniaturization 总被引:1,自引:0,他引:1
Jiin-Jang Maa Ching-Yuan Wu 《Electron Devices, IEEE Transactions on》1995,42(8):1487-1494
The formulation, verification, and application of a new simplified 2-D threshold voltage model for n-MOSFETs with nonuniformly doped substrate profile are provided, in which the averaged normal field at the Si/SiO/sub 2/ interface in the active channel is quoted from a simplified solution of two-dimensional Poisson equation using the Green function technique. Starting with the expression of this average normal field, a simple threshold-voltage model for short-channel n-MOSFETs with nonuniformly doped substrate profile is explicitly expressed in terms of device structures and terminal voltages by considering parabolic source-drain boundary potentials. Moreover, the effects of the junction depth on the threshold voltage are examined in detail. It is shown that the DIBL effect cannot be completely eliminated by simply increasing the substrate doping concentration. Comparisons among developed model, 2-D numerical analysis, and experimental data have been made and the accuracy of the developed analytical model has been verified. In addition, a direct extension of our model to the case of uniformly doped substrates leads to a new constraint equation for device miniaturization.<> 相似文献
33.
Normally a complicated three-dimensional (3-D) approach is needed to study the field pattern of induction machines with skewed rotor bars. In this paper, a time-stepping two-dimensional (2-D) eddy-current finite element method, based on multislice technique, is described to study the steady-state operation and the starting process of skewed rotor induction machines. The fields of the multislices are being solved en bloc simultaneously, and thus, the effects of the eddy current and saturation can be taken into account directly. New forms of the governing equations for the multislice model are derived, which allow the meshes of multislices to be taken as one 2-D mesh so that the algorithm is very similar to that of general 2-D problems. Special techniques required for the mesh generation in the multislice model and the salient structures of the software are also described. The results obtained by using the program being developed have very good correlation with test data 相似文献
34.
Core–shell type nanoparticles of poly(L ‐lactide)/poly(ethylene glycol) (LE) diblock copolymer were prepared by a dialysis technique. Their size was confirmed as 40–70 nm using photon correlation spectroscopy. The 1H‐NMR analysis confirmed the formation of core–shell type nanoparticles and drug loading. The particle size, drug loading, and drug release rate of the LE nanoparticles were slightly changed by the initial solvents that were used. The drug release behavior of LE core–shell type nanoparticles showed an initial burst during the first 12 h and then a sustained release until 100 h. The degradation behavior of LE block copolymer nanoparticles was divided into three phases: the initial rapid degradation phase, the stationary phase, and the rapid degradation phase until complete degradation. It was suggested that lidocaine release kinetics were predominantly governed by the diffusion mechanism in the initial burst phase and after that by both of the diffusion and degradation mechanisms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2625–2634, 2002 相似文献
35.
Carl A. Soderstrom Patricia C. Dischinger Gordon S. Smith J.Richard Hebel David R. McDuff David A. Gorelick Timothy J. Kerns Shiu M. Ho Kathleen M. Read 《Accident; analysis and prevention》1997,29(6):715-721
A structured in-depth interview employing standardized criteria was used to determine the prevalence of lifetime and current alcohol dependence (alcoholism) in unselected consecutive patients admitted to a regional Level I trauma center. Of 629 patients, 157 (25.0%) were current alcoholics at the time of injury. An additional 87 (13.8%) were diagnosed as lifetime non-current alcoholics. There was no significant difference in the rates of current alcohol dependence among patients injured in vehicular crashes (23.5%), other unintentional trauma victims (29.3%), and those injured as a result of violence (24.6%). Of BAC + (blood alcohol concentration positive) patients, 54.5% were current alcoholics. However, 14.4% of alcohol-negative patients were also diagnosed as alcohol dependent. 相似文献
36.
Shye Lin Wu Chung Len Lee Tan Fu Lei Chen C.F. Chen L.J. Ho K.Z. Ling Y.C. 《Electron Device Letters, IEEE》1994,15(4):120-122
In this study, it is demonstrated that the incorporation of fluorine can enhance poly-Si/Si interfacial oxide break-up in the poly-Si emitter contacted p+-n shallow junction formation. The annealing temperature for breaking up the poly-Si/Si interfacial oxide has been found to be as low as 900°C. As a result, the junction depth of the BF2-implanted device is much larger than that of the boron-implanted device 相似文献
37.
38.
Low temperature heat capacity measurements have been made on hot isostatically pressed Nb3Sn and arc cast, homogenized, and A15 transformation annealed V-23.3 at. pct Ga and V-18.1 at. pct Ga. The heat capacity measurements
display the superconducting transition temperature (T
c), and have been used to evaluate the effects of plastic deformation on theT
c range. Plastic deformation to the extent of 15 pct compression at 1525 and 1650 °C does not alter the superconducting transition
in polycrystalline Nb3Sn. Plastic deformation to the extent of 15 pct compression at 1050 and 1200 °C does not alter the superconducting transition
in polycrystalline V-23.3Ga, transformed to A15 structure with a fifty-hour 1150 °C anneal. The same statement can be made
for A15 V-18.1Ga, deformed at 1050 °C after a fifty-hour, 1150 °C anneal. With onlyfive hours annealing at 1150 °C, A15 V-23.2Ga displays a lowering and broadening of theT
c range upon 1050 and 1200 °C plastic deformation. With onlyfive hours annealing at 1150 °C, A15 V-18.1Ga displays a broad, but increasedT
c range after plastic deformation at 1050 °C. 相似文献
39.
Sung Ho Jeong Joon Jeong Yi Jong Keun Kim Man Yeong Ha 《Journal of Mechanical Science and Technology》1991,5(1):16-21
A computer program to calculate the strip temperature heated in the continuous annealing furnace was developed, using the
zone method for radiative heat transfer analysis with the measured gas temperature in the furnace. Using theF
E Operator, the present study considered the effects of soot and transient species, in addition to the H2O−CO2 gas mixture on the gas radiative heat transfer. The predicted strip temperature distribution forF
E=1.05 represented well the measured data. The maximum difference in the heat flux transfered to the strip from the combustion
gas forF
E=1.0 (without soot and transient species gas radiation) and 1.05 (with soot and transient species gas radiation) was about
15%. The present study also investigated the effects of line speed and thickness variations on the strip temperature, establishing
the bases for the on-line computer model. 相似文献
40.
Ho A.N. Pantell R.H. Feinstein J. Huang Y.C. 《Quantum Electronics, IEEE Journal of》1991,27(12):2650-2655
A novel wiggler design for use in free-electron lasers (FELs) is proposed, consisting of a staggered array of magnetic poles situated inside the bore of a solenoid. The resultant field pattern consists of a periodic transverse magnetic field on axis, as well as a longitudinal guide field. Such a wiggler has several advantages: the longitudinal field acts to confine the electrons near the FEL axis, high fields can be attained at short wiggler periods, the field strength is easily varied, and fabrication and testing of the wiggler are relatively easy. It is planned to use this wiggler design in a far infrared FEL to be built at Stanford University 相似文献