Half-bridge SIC inverter for hybrid electric vehicles: Design, development and testing at higher operating temperature

In recent years, Silicon Carbide (SiC) semiconductor devices have shown promise for high density power electronic applications, due to their electrical and thermal properties. In this paper, the performance of SiC JFETs for hybrid electric vehicle (HEV) applications is investigated at heatsink temperatures of 100 °C. The thermal runaway characteristics, maximum current density and packaging temperature limitations of the devices are considered and the efficiency implications discussed. To quantify the power density capabilities of power transistors, a novel 'expression of rating' (EoR) is proposed. A prototype single phase, half-bridge voltage source inverter using SiC JFETs is also tested and its performance at 25 °C and 100 °C investigated.

DISORDER POINT FOR 2D ELECTRONS IN A HALF-FILLED LANDAU-LEVEL

Short-range correlations of two-dimensional electrons in a strong magnetic field are shown to be triangular in nature well below half-filling, but honeycomb well above half-filling. The half-filling point is thus proposed, and qualitatively confirmed by three-body correlation calculations, to be a new type of disorder point where short-range correlations change character. A wavefunction study also suggests that nodes become unbound at half-filling. Evidence for incompressibility but deformability of the half-filling state earlier suggested by Fano, Ortolani and Tosatti, is also presented and found to be in agreement with recent experiments.

A new half-flash architecture for high speed video ADC

In this paper a new half-flash architecture for high speed video ADC is presented. Based on a high speed single-way analog switch circuit, this architecture effectively reduces the number of elements. At the same lime no sacrifice of speed is needed compared with the normal half-flash structure.

Period-doubling bifurcations of the thermocapillary convection in a floating half zone

This study experimentally explored the fine structures of the successive period-doubling bifurcations of the time-dependent thermocapillary convection in a floating half zone of 10 cSt silicone oil with the diameter d (0)=3.00 mm and the aspect ratio A=l/d (0)=0.72 in terrestrial conditions. The onset of time-dependent thermocapillary convection predominated in this experimental configuration and its subsequent evolution were experimentally detected through the local temperature measurements. The experimental results revealed a sequence of period-doubling bifurcations of the time-dependent thermocapillary convection, similar in some way to one of the routes to chaos for buoyant natural convection. The critical frequencies and the corresponding fractal frequencies were extracted through the real-time analysis of the frequency spectra by Fast-Fourier-Transformation (FFT). The projections of the trajectory onto the reconstructed phase-space were also provided. Furthermore, the experimentally predicted Feigenbaum constants were quite close to the theoretical asymptotic value of 4.669 [Feigenbaum M J. Phys Lett A, 1979, 74: 375-378].

Theoretical Analysis and New Formulae for Half-Lives of Proton Emission

The proton radioactivity half-lives of spherical proton emitters are calculated by the cluster model with the contribution of a centrifugal potential barrier considered separately. The results are compared with the experimental data and other theoretical data, and good agreement is found for most nuclei. In addition, two formulae are proposed for the proton decay half-life of spherical proton emitters through the least squares fit to the experimental data available, and could reproduce the experimental half-lives successfully.

Cluster preformation in heavy nuclei and radioactivity half-lives

Various cluster radioactivities of heavy nuclei have been investigated by using the unified fission model (UFM). The cluster preformation factors have been extracted by employing the UFM connected with the experimental half-lives, and the relationship of preformation probability between the cluster and alpha-particle has been discussed in detail. In addition, the cluster preformation probability has been studied in the framework of statistical physics. Some useful predictions on the cluster emission half-lives are provided for future experiments.

alpha-decay half-lives of superheavy nuclei and general predictions

The generalized liquid drop model (GLDM) and the cluster model have been employed to calculate the alpha-decay half-lives of superheavy nuclei (SHN) using the experimental alpha-decay Q values. The results of the cluster model are slightly poorer than those from the GLDM if experimental Q values are used. The prediction powers of these two models with theoretical Q values from Audi et al. (Q(Audi)) and Muntian et al. (Q(M)) have been tested to find that the cluster model with Q(Audi) and Q(M) could provide reliable results for Z > 112 but the GLDM with Q(Audi) for Z <= 112. The half-lives of some still unknown nuclei are predicted by these two models and these results may be useful for future experimental assignment and identification.

Alpha decay half-lives of heavy nuclei within a generalized liquid drop model

Theoretical alpha-decay half-lives of the heaviest nuclei are calculated using the experimental Q value. The barriers in the quasi-molecular shape path is determined within a Generalized Liquid Drop Model (GLDM) and the WKB approximation is used. The results are compared with calculations using the Density-Dependent, M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulae. The calculations provide consistent estimates for the half-lives of the a decay chains of these superheavy elements. The experimental data stand between the GLDM calculations and VSS ones in the most time.

Half-Lives of Superheavy Nuclei in Z=113 Alpha Decay Chain

The generalized liquid drop model (GLDM), including the proximity effects and centrifugal potential, and the cluster model with Cosh potential are used to study the half-lives of some Z=113 isotopes and their alpha-decay products.The experimental half-lives of (284)113, (283)113, (282)113and their alpha-decay products are well reproduced by the two models when zero angular momenta transfer is assumed. For (278)113 and its alpha-decay products, both the GLDM andthe cluster model could provide satisfactory results if we assume the alpha particle carry five units of angular momenta, which indicates that possible non zero angular momenta transfer and need further experimental measurements with high precision. Finally, we show that half-lives of alpha-decay are quite sensitive to the angular momentum transfers, and a formula could be used to describe the correlation between alpha-decay half-life and angular momentum transfer successfully.