Design and AC Loss Analyze of a 10 MW-Rated HTS Wind Turbine Generator

Journal of Superconductivity and Novel Magnetism - We present key design parameters of an innovative 10 MW low-speed direct-drive superconducting generator by high-temperature...     

Preparation of methacrylamide grafted and dye-ligand immobilized PET fibers: Studies of adsorption and purification of lysozyme

In this study, novel affinity chromatographic fibers was prepared from methacrylamide grafted poly(ethylene terephthalate), PET-g-pMAA, using benzoylperoxide as an initiator. A dye ligand (i.e., Procion Brown) as a ligand was then covalently immobilized on the different amount of pMAAm grafted PET fibers, (PET-g-pMAAm-PB). The fibers were characterized by surface area measurement, infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Adsorptive properties of the composite fibers were tested using a model protein (i.e., lysozyme). To achieve these purposes, the influence of pH, ionic strength, initial lysozyme concentration, and temperature on adsorption system has been investigated and evaluated. A maximum lysozyme adsorption PET-g-pMAAm-PB fiber was obtained as 43.9 mg g⁻¹ at pH 7.5. The experimental equilibrium data obtained for lysozyme adsorption onto PET-g-pMAAm-PB fibers fitted well to the Langmuir isotherm model. The result of kinetic analyzed for lysozyme adsorption onto affinity fibers showed that the second-order rate equation was favorable. The purity of the eluted lysozyme, as determined by HPLC, was 84% with recovery 73% for PET-g-pMAAm-PB fiber. Experiments on regeneration and dynamic adsorption were also performed. It appears that PET-g-pMAAm-PB fibers can be applied for lysozyme separation without causing any denaturation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Immobilization of urease and estimation of effective diffusion coefficients of urea in HEMA and VP copolymer matrices

Enzyme urease was immobilized in copolymer matrices of 2-hydroxyethyl methacrylate (HEMA) and N-vinyl pyrrolidone (VP). The activities of immobilized urease stored in phosphate buffer solution of pH 7.0 at 4°C were examined periodically for up to 90 days. For the matrices of higher VP/HEMA mole ratio in the structure, a higher volume increase and enhanced apparent activity were observed, while HEMA polymer alone proved to have the most stable matrix for prolonged activity. No appreciable amount of enzyme leakage was experienced for any of the matrices prepared. The effective diffusion coefficients of urea through these polymer matrices were calculated with a ‘diffusion and reaction’ model and the highest effective diffusion coefficient was found with pure HEMA matrix, possibly due to its laminated structure.     

Dielectric properties in Au/SnO2/n-Si (MOS) structures irradiated under Co-γ rays

The metal-oxide-semiconductor (MOS) structures with insulator layer thickness range of 55-430 Å were stressed with a bias of 0 V during ⁶⁰Co-γ ray source irradiation with the dose rate of 2.12 kGy/h and the total dose range was 0-5×10⁵ Gy. The real part of dielectric constant ε′, dielectric loss ε″, dielectric loss tangent tanδ and the dc conductivity σ_dc were determined from against frequency, applied voltage, dose rate and thickness of insulator layer at room temperature for Au/SnO₂/n-Si (MOS) structures from C-V capacitance and G-V conductance measurements in depletion and weak inversion before and after irradiation. The dielectric properties of MOS structures have been found to be strongly influenced by the presence of dominant radiation-induced defects. The frequency, applied voltage, dose rate and thickness dependence of ε′, ε″, tanδ and σ_dc are studied in the frequency (500 Hz-10 MHz), applied voltage (−10 to 10 V), dose rate (0-500 kGy) and thickness of insulator layer (55-430 Å) range, respectively. In general, dielectric constant ε′, dielectric loss ε″ and dielectric loss tangent are found to decrease with increasing the frequency while σ_dc is increased. Experimental results shows that the interfacial polarization can be more easily occurred at the lower frequency and/or with the number of density of interface states between Si/SnO₂ interfaces, consequently, contribute to the improvement of dielectric properties of Au/SnO₂/n-Si (MOS) structures.     

Studies on Sustained Release IV: Inert Matrix Tablets of Sulfamethizole, Employing Pdlyvinyl Chloride and Carboxypolymethylene

An inert matrix type sulfamethizole sustained release dosage form is attempted, using polyvinyl chloride and carboxypolymethylene. The release obtained with the flow -through cell is lower than the target profile. With the rotating bottle apparatus, higher release rates were obtained, but based upon our previous findings, the latter method is considered not to be very realistic.

Upon the kinetic assessment of dissolution data, zero order, first order and Hixson-Crowell kinetics were found to give similar fits.     

基于子空间的空时分组码的解码

空时码解码算法往往假设信道状态信息(CSI)已经事先估计出,信道估计需要额外的运算量,而且信道估计误差使解码性能降低.本文提出一种基于子空间方法的空时分组码直接解码算法,利用空时分组码的结构,结合子空间算法,可以不需要信道信息,直接得到码符信息的闭式解.仿真实验结果表明,随着噪声子空间求解准确度的提高,直接解码算法性能逐渐接近使用确切信道信息的相关解码器.     

SYNTHESIS AND CHARACTERIZATION OF BORON CARBIDE FILMS BY PLASMA-ENHANCED CHEMICAL VAPOR DEPOSITION

The plasma-enhanced chemical vapor deposition of boron carbide was investigated on quartz glass and alumina substrates from a gas mixture of BCl 3 , H 2 , and CH 4 in an inductively coupled plasma (ICP) medium produced by a radio frequency (RF) discharged onto the gases passing through a tubular reactor under atmospheric pressure. A thin solid boron carbide coating with a gray color was deposited on both substrates. The results of XRD revealed that the major solid phase formed in the coating material was β-rhombohedral B 4 C. The SEM analysis showed that the surface homogeneity increased with an increase in the exposure time, and different boron carbide structures were formed at different RF powers and exposure times.