三相电压型SVPWM整流器控制策略研究

提出了一种便于数字实现的三相电压型PWM整流器控制方案,该方案基于矢量控制的思想,采用输入电压空间矢量定向,结合直接电流控制的方法进行电流跟踪控制,提高了整流器的整体性能,仿真结果证明了该方案的有效性.     

EAST中性束注入器加速极电源设计

文章介绍了80 kV,80A EA ST托卡马克装置中性束注入器加速极电源的设计方案,该方案利用脉阶调制技术,引入一种新颖的80个不可控直流电源模块串联的解决方案;加速极电源的输出电压取决于投入的模块数,通过开关可调节输出电压在0%~100%额定电压范围内阶梯变化;与传统的整流加串联真空调整管方案相比较,该方案具有多方面的优点。     

无线局域网中补码键控技术的研究

介绍了一种无线局域网的调制方法——补码键控．给出了无线局域网中补码键控的实现过程，通过应用Matlab对其进行了Matlab仿真试验，证明了该方法的可行性与优越性。     

变频器使用中的问题与处理

介绍了中铝山西分公司变频调速器的使用情况，针对使用中经常遇到的一些问题，如跳闸和变频器显示过电压、变频器电压测量不准确等，着重讨论了变频器故障分析与处理的方法。     

采用相位调制的三级阶梯波逆变器门驱信号发生器

相位调制在抑制输出谐波和输出自动稳压的敏感性方面比幅度调制有明显的优点．本文报告了一个三电平逆变器的门驱信号发生器，6个信号分成二组并严格对称．一组用于驱动逆变器功率电路的正半周，一组用于驱动逆变器功率电路的负半周，合成一个完整．三电平逆变输出，每个开关的切换角，即相位可调．文中还报告了一种具体的逆变器实验电路及其测试结果．     

表面等离子体共振生物传感器研究人参皂甙与血清白蛋白的相互作用

To use a newly developed wavelength modulation surface plasmon resonance （SPR） biosensor, an experimental protocol was developed to investigate the interaction of ginsenosides with serum albumin. With a known concentration of the ginsenosides, bound percentages of the ginsenosides with human serum albumin （HSA） or bovine serum albumin （BSA） were obtained. SPR technique could require no labeling and this method provided the detailed information on association and disassociation of molecules in real time. The results indicate that the sensitivity of wavelength modulation SPR biosensor is sufficient for detection and characterization of binding events involving low-molecular weight compounds and their immobilized protein targets.     

Application of solid-phase micro-extraction and comprehensive two-dimensional gas chromatography (GC×GC) for flavour analysis

Summary Headspace solid-phase micro-extraction (HS SPME), comprehensive two-dimensional GC (GC×GC), and flame ionization detection (FID) have been examined for their suitability and compatibility for rapid sampling, separation, and detection of garlic flavour volatiles. This approach (HS-SPME-GC×GC-FID) is distinctly superior to use of one-dimensional GC, i. e., HS-SPME-GC-FID. Direct comparison of the experimental results showed that a 10–50-fold increase in sensitivity is obtained, separating power is substantially enhanced, and the peak capacity is up to ten times higher. As a consequence, much more detailed flavour analysis can be performed; this results in better information about the aroma-active compounds.     

A novel class of allosteric modulators of the muscarinic M2 acetylcholine receptor: terphenyl derivatives

The allosteric modulation of receptors has become a widely accepted concept in order to enhance the agonist or antagonist binding to a receptor. Alcuronium, characterized by a high allosteric potency and a positive cooperativity at the muscarinic M₂ receptor, was chosen as a template to design a structural novel terphenyl-type of allosteric modulator. The skeleton was build up from 1-bromo-2-methylnaphthalene and 1,4-dibromo-2,5-dimethylbenzene using bis(triphenylphosphine)nickel(II) dichloride as a catalyst. Several amino substituted terphenyls were synthesised and preliminary pharmacological tests were performed.     

A compact NIR fiber-optic diode laser spectrometer for CO and CO(2): analysis of observed 2f wavelength modulation spectroscopy line shapes

A compact fiber-optic diode laser spectrometer for the measurement of CO and CO(2) gas concentrations in the near infrared around 1580 nm is described. By use of a balanced receiver to suppress diode laser intensity noise a sensitivity of 6.4 x 10(-7) at 1 Hz system bandwidth was achieved. At a reduced pressure of 80 hPa this equals to a detection limit of 5.1 ppm CO and 9.1 ppm CO(2) with 1m absorption path length. The observed line shapes of the 2f wavelength modulation spectroscopy (WMS) scheme are analyzed theoretically and experimentally. Accurate measurements of magnitude and phase of the diode laser frequency and intensity modulation responses were found critically for modeling the observed line shapes. In situ measurements of gas dissociation processes inside of a medium-power carbon dioxide laser are presented as an application example.     

Development of highly fluorescent photochromic material with high fatigue resistance

Efficient and reversible fluorescence modulation with excellent photo-stability was achieved from a sulfone form of diacetyl diarylethene, 1,2-bis(6-acetyl-2-methyl-1-benzothiophene-1,1-dioxide-3-yl)perfluorocyclopentene (DABTFO4). The DABTFO4 emits strong fluorescence in the closed-ring isomer even in the absence of extra fluorophores. The fluorescence quantum yield, fatigue resistance, and photo-cyclization yield of DABTFO4 were significantly improved compared with the unsubstituted 1,2-bis(2-methyl-1-benzothiophene-1,1-dioxide-3-yl)perfluorocyclopentene (BTFO4) and the sulfide analogue, 1,2-bis(6-acetyl-2-methyl-1-benzothiophene-3-yl)perfluorocyclopentene (DABTF6).