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111.
112.
The auto-charge pump is a self-starting and self-sustaining circuit used to generate a floating voltage supply for the high side circuitry of half-bridge inverters. The switching output of the half-bridge replaces the dedicated pump oscillator thus simplifying the circuit. A model is derived which is then verified experimentally 相似文献
113.
114.
In this work, we deal with the 1D compressible fluid coupled with elastic solid in an Eulerian-Lagrangian system. To facilitate
the analysis, the Naviers equation for elastic solid is cast into a 2×2 system similar to the Euler equation but in Lagrangian
coordinate. The modified Ghost Fluid Method is employed to treat the fluid-elastic solid coupling, where an Eulerian-Lagrangian
Riemann problem is defined and a nonlinear characteristic from the fluid and a Riemann invariant from the solid are used to
predict and define the ghost fluid states. Theoretical analysis shows that the present approach is accurate in the sense of
approximating the solution of the Riemann problem at the interface. Numerical validation of this approach is also accomplished
by extensive comparison to 1D problems (both water-solid and gas-solid) with their respective analytical solutions.
T.G. Liu’s current address: Department of Mathematics, Beijing University of Aeronautics and Astronautics, Beijing 100083.
email: liutg@buaa.edu.cn. 相似文献
115.
Hyunjin Lim Sooyoun Park Hyeonsik Cheong Hyun-Min Choi Young Chool Kim 《Diamond and Related Materials》2010,19(10):1254-1258
We have performed low-temperature (8 K) photoluminescence (PL) measurements on 71 natural and 12 high-pressure-and-high-temperature (HPHT)-treated type IIa diamonds. The GR1, NV0, NV?, H4, and H3 defect center PL signals are compared. Some distinct differences in the PL lineshape, intensity, and appearance of side-band PL signals are observed. Furthermore, we processed 6 of the natural diamond samples with the HPHT treatment to investigate the effect of the treatment on the PL spectrum. By systematically analyzing the differences in the PL spectra, we developed a scheme to discriminate natural and HPHT-treated diamonds with 99% validity. 相似文献
116.
Kwan-Ho Park Il-Ho Kim Soon-Mok Choi Won-Seon Seo Dong-Ik Cheong Hyung Kang 《Journal of Electronic Materials》2013,42(7):1377-1381
p-Type Yb z Fe4?x Co x Sb12 skutterudites were prepared by encapsulated melting and hot pressing, and the filling and doping (charge compensation) effects on the transport and thermoelectric properties were examined. The electrical conductivity of all specimens decreased slightly with increasing temperature, indicating that they were in a degenerate state due to high carrier concentrations of 1020 cm?3 to 1021 cm?3. The Hall and Seebeck coefficients exhibited positive signs, indicating that the majority carriers are holes (p-type). The Seebeck coefficient increased with increasing temperature to maximum values of 100 μV/K to 150 μV/K at 823 K. The electrical and thermal conductivities were reduced by substitution of Co for Fe, which was responsible for the decreased carrier concentration. Overall, the Yb-filled Fe-rich skutterudites showed better thermoelectric performance than the Yb-filled Co-rich skutterudites. 相似文献
117.
Wai-Fun Leong Kok-Whey Cheong Oi-Ming Lai Kamariah Long Yaakob B. Che Man Misni Misran Chin-Ping Tan 《Journal of the American Oil Chemists' Society》2011,88(5):717-725
The purpose of this study was to optimize the production parameters for water-soluble phytosterol nanodispersions. Response
surface methodology (RSM) was employed to model and optimize three of the processing parameters: mixing time (t) by conventional homogenizer (1–20 min), mixing speed (v) by conventional homogenizer (1,000–9,000 rpm) and homogenization pressure (P) by high-pressure homogenizer (0.1–80 MPa). All responses [i.e., mean particle size (PS), polydispersity index (PDI) and
phytosterols concentration (Phyto, mg/l)] fitted well to a reduced quadratic model by multiple regressions after manual elimination.
For PS, PDI and Phyto, the coefficients of determination (R
2) were 0.9902, 0.9065 and 0.8878, respectively. The optimized processing parameters were 15.25 min mixing time, 7,000 rpm
mixing speed and homogenization pressure 42.4 MPa. In the produced nanodispersions, the corresponding responses for the optimized
preparation conditions were a PS of 52 nm, PDI of 0.3390 and a Phyto of 336 mg/l. 相似文献
118.
Bulk unipolar diodes with a wide range of barrier heights have been made in hydrogenated amorphous silicon by ion implantation. The precise concentration of dopant atoms that can be obtained when implanting into an amorphous substrate leads to accurate barrier height control. Compared with the alternative unipolar device, the Schottky diode, these devices should provide uniform, high barrier diodes for photodetectors, and very low barrier diodes for low-power, unbiased, mixers and detectors 相似文献
119.
Nagalingam Saravanan Geok Bee Teh Samuel Yong Peen Yap Kar Mun Cheong 《Journal of Materials Science: Materials in Electronics》2008,19(12):1206-1208
ZnS nanoparticles were successfully synthesized by reflux under an alkaline medium. The nanoparticles were characterized by
using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical
properties of ZnS nanoparticles were examined by photoluminescence (PL) spectrum. The result shows that the as-synthesized
ZnS nanoparticles had a cubic phase. SEM image shows that ZnS nanoparticles are basically in spherical shape and are homogeneous.
The particle size was found to be in the range of 18 nm. 相似文献
120.
Methods for assessing treatment effects of longitudinal randomized intervention are considered. The focus is on modeling the nonlinear relationship between treatment effects and baseline often observed in prevention programs designed for at-risk populations. Piecewise linear growth modeling was used to study treatment effects during the different periods of development. A multistep multiple-group analysis procedure is proposed for assessing treatment effects in the presence of nonlinear treatment-baseline interactions. Standard errors of the estimates from this multistep procedure were obtained using a bootstrap approach. The methods are illustrated using data from the Johns Hopkins Prevention Research Center involving an intervention aimed at improving classroom behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献