1,721,595 research outputs found
Full ZVS-range transient current buildup half-bridge converter with different ZVS operations to load variation
No full textA full zero voltage switching (ZVS) range transient current buildup half-bridge converter,is proposed. The proposed converter controls the secondary synchronous switches to build up the current for the ZVS operation. In addition, the blocking capacitor in the secondary side of the transformer is used to make the different current buildups and different ZVS operations with the load variation. Furthermore, it eliminates the dc offset of the magnetizing current. Therefore, the considerably effective ZVS characteristics can be ensured in the full-load ranges without any additional conduction losses
High-efficiency boost half-bridge converter with fast boost current transferring ZVS operation
No full textA new boost half bridge (BHB) converter is presented. It is composed of additional switch, diode and coupled winding to boost inductor of BHB converter. Using the transferring of boost inductor current to coupled winding in a short period, the cancellation of zero voltage switching (ZVS) current, which always occurs in convention one, is prevented. Therefore, the ZVS operation is easily achieved by leakage inductor current of transformer. Furthermore, since negatively build-up leakage inductor current of boost winding helps the ZVS operation throughout full load range, the excellent ZVS operation and high efficiency is achieved
Enzymatic reduction of shogaol: A novel biotransformation pathway for the alpha, beta-unsaturated ketone system
No full textA novel reductive metabolism of 1-(4-hydroxy-3-methoxyphenyl)-deca-4-ene-3-one (shogaol), a pungent principle of ginger, was investigated in rat liver in vitro. Ethyl acetate-extractable metabolites of shogaol formed by incubation of this alpha,beta-unsaturated ketone with rat liver cytosolic fraction fortified with NADPH or NADPH-generating system were isolated, and two major metabolites were identified as 1-(4-hydroxy-3-methoxyphenyl)-decan-3-one (paradol) and 1-(4-hydroxy-3-methoxy)-decan-3-ol (reduced paradol). 1-(4-hydroxy-3-methoxyphenyl)-deca-1-ene-3-one (dehydroparadol), a non-pungent analog of shogaol, formed the same metabolites as did shogaol under similar incubation conditions. Paradol appears to be an intermediate in the reductive metabolism of the alpha,beta-unsaturated ketone moiety of shogaol to the corresponding saturated alcohol.N
POSITION OF NONLINEAR ELEMENTS AND IDENTIFICATION OF THEIR TYPE BY A LOCAL NONPARAMETRIC METHOD
No full textDevelopment of indium tin oxide film texture during DC magnetron sputtering deposition
No full textThe indium tin oxide (ITO) film texture development process during sputtering deposition was explored. Cross-section TEM images revealed that prepared ITO films have columnar structures. theta - 2theta X-ray diffraction (XRD) studies on ITO thin films deposited under various sputtering conditions were conducted. The change of XRD profiles with increasing thickness was monitored to elucidate the mechanism of film texture development. ITO films, which were deposited under conventional conditions, evolved to (400) orientation with increasing film thickness. In contrast, surplus amounts of additional oxygen gas flow suppressed growth of (400)-oriented grains. Meanwhile, moderate ranges of pressure and power density and higher substrate temperatures resulted in more (400)-oriented film textures. The development of texture to (400) orientation is attributed to a lower surface energy and a height advantage combined with shadowing effect. The ITO film growth process was assumed to be composed of two steps, the nucleatiom step and the evolution step. Higher adatom mobility is thought to be very important for the nucleation of (400)-oriented grains. (C) 2003 Elsevier B.V. All rights reserved
Iterative Curve Fitting Method to Extract a Constrained Optimum Design Parameter from the Best Possible Performance Result
No full textIntegrated optical waveguide based on photobleaching-induced birefringence in an electro-optic polymer
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