高效回收镍盐化工污泥制取硫酸镍技术工艺分析

对镍盐化工污泥中镍的浸出条件进行了分析和考察,对浸出液中沉铁和沉镍的p H值进行了系统的分析;采用水洗工艺对粗产品中氢氧化镍杂质的去除效果进行分析,最终采用加酸溶解和蒸发结晶的方式制取硫酸镍产物。     

The Harmonic Analysis of RMP Coil Power Supply in EAST TOKAMAK

In EAST TOKAMAK, resonant magnetic perturbation (RMP) coils, which are powered by RMP coil power supply (PS), are set to research edge localized mode, resistive wall mode and error field correction. In order to meet the requirements of fast response and output voltage ripple proposed by physical experimenters, the structure of multiple modules using cascaded carrier phase-shifted PWM H-bridges is adopted, which enhances the equal switch-frequency of the PS and improves the quality of output voltage. In the paper, theoretical calculation applying Fourier analysis is given to analyze its harmonics. Both simulation results on Matlab and test results of output voltage ripple show that the RMP coil PS can meet the requirements.     

Distribution of Melaleuca alternifolia essential oil in liposomes with Tween 80 addition and enhancement of in vitro antimicrobial effect

Tea tree oil (TTO) exhibits excellent broad-spectrum antimicrobial activity. In order to preserve it from the degradation in the presence of oxygen, light and temperature, TTO was encapsulated in liposomes (LTTOs) using the thin-membrane hydration and sonication method, and characterised by Zetasizer for size and size distribution, transmission electron microscope for morphology, zeta-potential for surface charge, entrapment efficiency and TTO release from the nanoparticles. The antimicrobial activities of phosphate-buffered saline solution containing TTO, unloaded liposomes and LTTOs suspension were determined by twofold serial broth dilution technique. The size of LTTOs was 75 nm and the encapsulation efficiency of 96.08% was obtained. LTTOs exhibited slow release of TTO and superior broad-spectrum antimicrobial effects compared with free TTO. Liposomes not only effectively encapsulated TTO to form a stable liposome suspension, but also enhanced inhibition and bactericidal effect on the TTO-tolerant strain. The liposomal systems carrying TTO may be a potential alternative for effective antimicrobial agents.     

Rheological properties and related screen-printing performance of low-temperature silver pastes for a-Si:H/c-Si heterojunction solar cells

Four different low-temperature silver pastes were utilized to make metal grids by screen printing for silicon heterojunction solar cells. The rheological behaviors of the low-temperature silver pastes were characterized by viscosity test, thixotropy test, oscillatory stress sweep test and creep-recovery test. The correlationship between the screen-printing performance and the rheological properties was investigated. It was found that the shear thinning behavior and the thixotropy behavior of the silver pastes were desirable for the screen-printing process. An obvious viscoelastic behavior of the silver paste was also helpful for improving its printability. Further, good recovery and low creep and recovery compliances could minimize the printing defects and the tendencies to bleed out during the screen-printing, and thus increase the aspect ratio of the printed grids.     

提案管理系统的设计与实现

介绍了-个采用PowerBuilder开发的提案管理系统.该系统采用客户端/服务器结构,分为用户管理、提案数据管理、任务数据管理、日志管理四个部分.描述了总体的设计思想、基本功能设计、数据库设计和关键技术.该系统能够帮助用户快速、方便的管理提案数据,在实际中得到了很好的应用.     

Bang-Bang Control Class D Amplifiers: Total Harmonic Distortion and Supply Noise

The total harmonic distortion (THD) and the power supply noise, qualified by the power supply rejection ratio (PSRR) and by the power supply induced intermodulation distortion (PS-IMD), are recognized to be potential drawbacks of class D amplifiers. In this paper, analytical expressions for the THD, PSRR, and PS-IMD of the bang-bang control class D amplifier (bang-bang amp) are derived; the bang-bang amp is arguably the most power-efficient class D amp for low-voltage power-critical applications including hearing aids. Based on the derived expressions, the effects of important parameters on the THD, PSRR, and PS-IMD are investigated, providing good insight to the design of the bang-bang amp to meet given design specifications. The analytical analyses are verified by comparing them against HSPICE simulations and hardware measurements. The bang-bang amp is also compared against the prevalent pulsewidth modulation class D amp, and in most cases, the former is shown to possess superior parameters, including lower power dissipation and hardware advantages for low-voltage power-critical applications.     

Study on antibacterial properties and major bioactive constituents of Chinese water chestnut (Eleocharis dulcis) peels extracts/fractions

Recently, considerable attention has been paid to the biologically active of fruit and vegetable processing wastes. In this study, antibacterial properties and major bioactive constituents of Chinese water chestnut peels (CWCP) extracts and fractions were evaluated. The data displayed that ethyl acetate fractions (EF) from CWCP showed greater antibacterial activity than n-butanol fractions, methanol extracts and water fractions against three common foodborne pathogenic bacteria (Staphylococcus aureus, Escherichia coli and Listeria monocytogenes) assessed by the inhibition zone, minimal inhibition concentration and minimal bactericidal concentration values. In accordance with disc diffusion assay, S. aureus was more susceptible to EF than the other two pathogens. Furthermore, action-mode studies indicated that EF exhibited significant bactericidal activity against S. aureus by degrading and disrupting the cell wall and cytoplasmic membrane, ultimately the leakage of cell contents led to cell death. Finally, high-performance liquid chromatography coupled with photodiode array and electrospray ionization mass spectrometry was used for characterization of bioactive constituents in EF, and ten flavonoids aglycons were identified or tentatively identified. The results suggest that the extracts and fractions from CWCP could be potentially used as a possible food supplement to improve food safety by the control or elimination of foodborne pathogenic bacteria.     

世界金融危机下上海天然气市场未来发展浅谈

文章简要描述了全球天然气发展趋势，并重点谈论了上海天然气的未来发展并提出了一些观点。     

Screening of <Emphasis Type="Italic">Candida utilis</Emphasis> and medium optimization for co-production of <Emphasis Type="Italic">S</Emphasis>-adenosylmethionine and glutathione

An effective S-adenosylmethionine and glutathione enriching yeast mutant of Candida utilis CCTCC M 209298 was first screened from plates containing 0.5 g/L of DL-ethionine by complex mutagenesis with UV and γ-ray in this study. Medium components optimization for enhanced co-production of S-adenosylmethionine and glutathione by C. utilis CCTCC M 209298 was further carried out using response surface methodology. The significant factors influencing S-adenosylmethionine and glutathione co-production were selected by Plackett-Burman design as sucrose, KH₂PO₄ and L-methionine, and Box-Behnken design was applied for further optimization studies. Based on these approaches, the optimized concentrations on medium components for higher co-production of S-adenosylmethionine and glutathione were sucrose 35.4 g/L, (NH₄)₂SO₄ 10 g/L, KH₂PO₄ 12.3 g/L, MgSO₄·7H₂O, 0.05 g/L, CaCl₂ 0.05 g/L and L-methionine 4.6 g/L. The medium optimization by response surface methodology led to a total production of 589.3 mg/L on S-adenosylmethionine and glutathione, which was 2.4-fold increased compared with the medium without optimization.