含磁控和荷控两种忆阻器的混沌电路设计与仿真

利用惠普实验室荷控和磁控两种忆阻器模型设计了一个五阶混沌电路. 数值仿真结果表明该电路在参数变化情况下能产生Hopf分岔和反倍周期分岔两种分岔行为,并能产生双涡卷、单涡卷、周期态等不同相轨道. 为了验证电路的混沌行为,利用基本元器件设计了惠普实验室荷控和磁控忆阻器模拟器,并将其应用到对所设计电路中进行Pspice仿真,电路仿真结果验证了理论分析的正确性. 关键词： 混沌电路 HP忆阻器 模拟器 Pspice仿真     

Novel combination of non-aqueous capillary electrophoresis and multivariate curve resolution-alternating least squares to determine phenolic acids in virgin olive oil

This paper presents the development of a non-aqueous capillary electrophoresis method coupled to UV detection combined with multivariate curve resolution-alternating least-squares (MCR-ALS) to carry out the resolution and quantitation of a mixture of six phenolic acids in virgin olive oil samples. p-Coumaric, caffeic, ferulic, 3,4-dihydroxyphenylacetic, vanillic and 4-hydroxyphenilacetic acids have been the analytes under study. All of them present different absorption spectra and overlapped time profiles with the olive oil matrix interferences and between them. The modeling strategy involves the building of a single MCR-ALS model composed of matrices augmented in the temporal mode, namely spectra remain invariant while time profiles may change from sample to sample. So MCR-ALS was used to cope with the coeluting interferences, on accounting the second order advantage inherent to this algorithm which, in addition, is able to handle data sets deviating from trilinearity, like the data herein analyzed. The method was firstly applied to resolve standard mixtures of the analytes randomly prepared in 1-propanol and, secondly, in real virgin olive oil samples, getting recovery values near to 100% in all cases. The importance and novelty of this methodology relies on the combination of non-aqueous capillary electrophoresis second-order data and MCR-ALS algorithm which allows performing the resolution of these compounds simplifying the previous sample pretreatment stages.     

信号侦察中的跳频信号识别方法

为了解决跳频设备已经大量装备而对跳频信号的侦察识别仍然困难的问题,作者提出了两种跳频信号识别方法,包括最大相关处理法和时间相关统计法.在对跳带内的信号进行数字信道化处理后,再经过最大相关处理,时-频图上的跳频信号的分布情况将会变得非常清晰;时间相关统计法是充分利用跳频信号在时间上的断续性和每跳间的连续性来识别跳频信号.经过实验验证,上述两种识别方法的使用,在跳频信号的侦察识别上效果非常明显.     

Preparation and characterization of Cobalt Sulfophthalocyanine/TiO2/fly-ash cenospheres photocatalyst and study on degradation activity under visible light

Cobalt Sulfophthalocyanine (CoSPc) sensitized TiO₂ sol samples were prepared through a Sol-Gel method using Cobalt Sulfophthalocyanine as a sensitizer. Loading and modified floating photocatalyst was prepared by hydrothermal method using fly-ash cenospheres as a carrier. The properties of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance spectrum (DRS). Photocatalytic activity was studied by degrading wastewater of methylene blue under visible light. The results indicate that the fly-ash cenospheres are covered by modified TiO₂ film which composed of the anatase, brookite and rutile misch crystal phase. CoSPc/TiO₂/fly-ash cenospheres samples have good catalytic activity under visible light, and have strong absorbency during 600-700 nm. The sensitization of CoSPc can enhance visible light catalytic activity of TiO₂/fly-ash cenospheres. The degradation rate of methylene blue reaches 73.36% in 180 min under the visible light illumination. But too much CoSPc can decrease its catalytic activity.     

Use of expanded bed adsorption to purify flavonoids from Ginkgo biloba L.

Three techniques (liquid–liquid extraction, packed bed adsorption and expanded bed adsorption) have been compared for the purification of flavonoids from the leaves of Ginkgo biloba L. A crude Ginkgo extract was obtained by refluxing with ethanol for 3 h. The yield of flavonoids achieved by this crude extraction was about 19% (w/w) and the purity of flavonoids in the concentrated extract was between 1.9 and 2.3% (w/w). The crude extract was then dissolved in deionized water and centrifuged where necessary to prepare clarified feedstock for further purification. For the method using liquid–liquid extraction with ethyl acetate, the purity, concentration ratio and yield of flavonoids were 25.4–31.0%, 16–18 and >98%, respectively. For the method using packed bed adsorption, Amberlite XAD7HP was selected as the adsorbent and clarified extract was used as the feedstock. The dynamic adsorption breakthrough curves and elution profiles were measured. For a feedstock containing flavonoids at a concentration of 0.25 mg/mL, the appropriate loading volume to reach a 5% breakthrough point during the adsorption stage was estimated to be 550–600 mL for a packed bed of volume 53 mL and a flow rate of 183 cm/h. The results from the elution stage indicated that the majority of impurities were eluted by ethanol concentrations of 40% (v/v) or below and efficient separation of flavonoids from the impurities could be achieved by elution of the flavonoids with 50–80% ethanol reaching an average purity of ∼25%. The recovery yield of flavonoids using the packed bed purification method was about 60% of the flavonoids present in the clarified feedstock (corresponding to around 30% for the total flavonoids in the unclarified crude extract). For the method using expanded bed adsorption also conducted with Amberlite XAD7HP as the adsorbent, the optimal operation conditions scouted during the packed bed experiments were used but unclarified crude extract could be loaded directly into the column. For an expanded bed with a settled bed height of 30 cm, the loss of flavonoids in the column flow-through was about 30%. The two-step elution protocol again proved to be effective in separating the adsorbed impurities and flavonoids. More than 96% of the bound impurities were completely removed by 40% ethanol in the first elution stage and less than 4% remained in the final product eluted by 90% ethanol in the second elution stage. Also, ∼74% of the adsorbed flavonoids on column (corresponding to 51% of the total flavonoids in the unclarified feedstock) were recovered in the product. In addition to higher recovery yield, the average process time to obtain the same amount of product was decreased in the expanded bed adsorption (EBA) process. The results suggest that the adoption of EBA procedures can greatly simplify the process flow sheet and in addition reduce the cost and time to purify flavonoids from Ginkgo biloba. These results clearly demonstrate the potential for the use of EBA to purify pharmaceuticals from plant sources.     

汕头Cable Modem接入业务报障的分析处理

本文就汕头Cable Modem接入业务的报障情况进行了分析,总结出六个问题并逐个说明其解决方法.     

铁—杂多酸液流电池的研究

本文报道的氧化还原流动池、负极活性物质为ＦｅＳＯ４，正极为Ｈ３ＰＭｏ１２Ｏ４０（ＨＰ），具有选择性的阳离子交换膜将两个经活化的多孔碳毯电极分开，两个氧化还原电对在碳和石墨电极上都具有相适应的电化学可逆性。电池的活性性质很稳定，电池没有使用寿命限制。     

消化性溃疡幽门螺旋杆菌感染和非感染患者血清微量元素的测定

对确诊ＨＰ阴性ＤＵ组２０例、ＨＰ阳性组２３例、ＨＰ阳性转阴性Ｄｕ组１２例血清多种微量元素测定，结果ＨＰ阳性Ｄｕ组钼、铬、锰、铜明显低于ＨＰ阴性Ｄｕ组，Ｐ＜０．０５或＜０．０１．ＨＰ含有多种酶，而微量元素多以金属酶存在于体内，可能两者相互影响，使ＨＰ感染患者微量元素降低，当ＨＰ感染清除后微量元素再升高，但其因果关系尚待深入研究。     

生理液中血卟啉溶液状态的光谱研究

本文通过对血卟啉在生理条件下(pH=7.2,I=0.5mol/LNaCl)水溶液中的光谱变化研究,探讨了其在溶液中的聚集状态。应用Kasha理论推算出血卟啉二聚体的面-面间距离为0.528nm,面间夹角为20°,平衡常数为2.85×10^-6.研究了在光作用下,血卟啉-人血清白蛋白溶液体系的光谱特性,讨论了光谱特性与血卟啉在癌瘤光化学治疗机制间的关系。     

Separation and determination of corynoxine and corynoxine B using chiral ionic liquid and hydroxypropyl‐β‐cyclodextrin as additives by field‐amplified sample stacking in capillary electrophoresis

A sensitive, fast, and effective method, field‐amplified sample stacking (FASS) in capillary electrophoresis, has been established for the separation and determination of corynoxine and corynoxine B. Hydroxypropyl‐β‐CD (HP‐β‐CD) and tetrabutylammonium‐L‐glutamic acid (TBA‐L‐Glu) were used as additives in the separation system. Electrokinetic injection was chosen to introduce sample from inlet at 10 kV for 50 s after a water plug (0.5 psi, 4 s) was injected to permit FASS. The running buffer (pH 6.1) was composed of 40 mM sodium dihydrogen phosphate solution, 130 mM HP‐β‐CD, and 10 mM TBA‐L‐Glu and the separation voltage was 20 kV. Under the optimum conditions, corynoxine and corynoxine B were successfully enriched and separated within 12 min and the sensitivity was improved approximately by 700–900 folds. Calibration curves were in a good linear relationship within the range of 62.5–5.00 × 10³ ng/mL for both corynoxine and corynoxine B. The limits of detection (S/N = 3) and quantitation (S/N = 10) were 14.9, 45.2 ng/mL for corynoxine and 11.2, 34.5 ng/mL for corynoxine B, respectively. Finally, this method was successfully applied for the determination of corynoxine and corynoxine B in the stems with hooks of Uncaria rhynchophylla and its formulations.