Generation of transient chaos from two-dimensional systems via a switching approach

A new approach of generating transient chaos from two-dimensional（2D） continuous autonomous systems within finite time is presented.Based on an absolute-value switching law,the phenomenon of transient chaos takes place by switching between three 2D systems.Basic dynamic behavior of the systems is investigated.Numerical examples illustrate the validity of the results.

Determination of Lansoprazole by Direct Injection of Plasma and High Performance Liquid Chromatography with Column Switching

High performance liquid chromatography with column switching has been developed for the determination of lansoprazole in plasma. The plasma samples were injected onto a pretreatment column packed with LiChromprep RP2 (25～40 mm) after simple dilution with distilled water. Distilled water was used to wash out protein and other polar components in plasma. After switching, the concentrated lansoprazole was eluted in the backflush mode onto a Shimpack CLC ODS column with methanol 0 2 mol·L 1 ammonium acetate (65:35) as mobile phase. Purge solutions were used for clean up and for regenerating the pretreatment column. The method showed good precision and recovery. The detection limit was 0 005 mg·L -1 plasma. The RSD’s (intra and interday) were less than 2 5% and 5 3% respectively. The method has been successfully used to determine pharmacokinetics of lansoprazole in Chinese volunteers.

Determination of petroleum sulfonates in crude oil by column-switching anion-exchange chromatography

A column-switching anion-exchange chromatography method was described for the separation and determination of petroleum monosulfonates （PMS） and petroleum disulfonates （PDS） in crude oil that was simply diluted with the dichloromethane/methanol （60/40）. The high performance liquid chromatography （HPLC） system consisted of a clean-up column and an analytical column, which were connected with two six-port switching valves. Detection of petroleum sulfonates was available and repeatable. This method has been successfully applied to determine PMS and PDS in crude oil samples from Shengli oil field.

Identification of Glyphosate Herbicide with Ion Chromatographic Column Switching Method

[Objective] The paper was to establish the method for quantitative analysis of glyphosate herbicide and identification of salt type. [Method] Using ion chromatographic column switching method,cations( sodion,ammonium ion,potassium ion,dimethonium ion and isopropylamine ion) and glyphosate anion in glyphosate salt were determined with Thermo IonP ac SCS1 cation exchange column and Thermo IonP ac AS14 anion exchange column,and external standard method was used for quantification. [Result] Various components showed good linear relationship within the linearity range,and the correlation coefficient r was greater than 0. 999; the relative standard deviation of retention time and peak area were less than 0. 13% and 1. 22%,respectively; the recovery was 98. 22%-99. 97%.[Conclusion] The method is precise,accurate and simple,and can be used to determine the active ingredients of glyphosate herbicide.

Development of simple HPLC/UV with a column-switching method for the determination of nicotine and cotinine in hair samples

Nicotine and cotinine in hair are good biomarkers for assessing long-term exposure to smoking. However, analytical devices such as GC/MS are associated with high cost and are not widely used. HPLC/UV is used widely in laboratories, but is unsuitable for measurement of minor constituents, except when using the column-switching method. Thus, we aimed to establish a simple, inexpensive and sensitive method based on HPLC/UV with column switching for measuring nicotine and cotinine in hair. First, we compared the presence and absence of a column selection unit. We then measured amounts of nicotine and cotinine in hair samples collected from the general population, and compared both the corresponding levels and the detection limits with those in previous studies. Finally, initial and running costs of HPLC/UV were compared with other analytical methods. As one of the results, the areas of nicotine and cotinine measured by HPLC/UV with column-switching method were 12.9 and 16.9 times greater, respectively, than those without the column-switching method. The amount of nicotine and cotinine in hair was significantly correlated to number of cigarettes smoked per day (r = 0.228, p = 0.040). In addition, the HPLC/UV method showed similar sensitivity and detection limit (nicotine, 0.10 ng/mg;cotinine, 0.08 ng/mg) as reported in previous studies. The cost of the HPLC/UV method is lower than that of other analytical methods. We were able to establish a low-cost method with good sensitivity for measuring nicotine and cotinine in hair. The HPLC/UV with a column-switching method will be useful as a first step in screening surveys in order to better understand the effects of smoking exposure.

Atomic crystals resistive switching memory

Facing the growing data storage and computing demands, a high accessing speed memory with low power and non- volatile character is urgently needed. Resistive access random memory with 4F2 cell size, switching in sub-nanosecond, cycling endurances of over 1012 cycles, and information retention exceeding 10 years, is considered as promising next- generation non-volatile memory. However, the energy per bit is still too high to compete against static random access memory and dynamic random access memory. The sneak leakage path and metal film sheet resistance issues hinder the further scaling down. The variation of resistance between different devices and even various cycles in the same device, hold resistive access random memory back from commercialization. The emerging of atomic crystals, possessing fine interface without dangling bonds in low dimension, can provide atomic level solutions for the obsessional issues. Moreover, the unique properties of atomic crystals also enable new type resistive switching memories, which provide a brand-new direction for the resistive access random memory.

基于在线柱切换液相色谱技术的红霉素软膏含量测定研究

目的建立在线柱切换高效液相色谱法测定红霉素软膏中主药含量的方法,为相关制剂的质量控制提供有效手段。方法样品经80℃提取后直接进样,柱切换系统下,采用C_(18)(50 mm×2.1 mm,5μm)色谱柱初步分离,2.5 min后转入C_(18)(150 mm×2.1 mm,5μm)柱进行分析,流速0.2 mL·min^(-1),柱温35℃。结果红霉素在1~100μg·mL^(-1)范围内线性关系良好(r=0.9994);平均加样回收率大于96.9%;日内和日间精密度小于1.29%(n=6)。结论本研究改进样品提取方法,并通过在线柱切换完成目标组分的净化和富集,该方法操作简单、准确灵敏、稳定性好,可用于红霉素软膏的含量测定。

头孢克洛聚合物杂质的分析

目的对头孢克洛中聚合物杂质的结构进行初步鉴定,对其产生机理进行初步分析。方法以0.05 mol/L磷酸盐缓冲液(pH 8.0)为溶剂,室温放置4 d,制备头孢克洛强制聚合溶液;采用HPSEC法对强制聚合物溶液中各杂质进行分离,结合二维液相脱盐技术、柱切换-LC/MS^(n)技术,根据各杂质一级、二级精确质量信息及聚合机制,初步鉴定主峰前各杂质结构。结果对头孢克洛强制聚合溶液中的9个聚合物杂质结构进行初步解析,并初步分析其产生机理。结论强制聚合溶液可作为头孢克洛原料及制剂中聚合物杂质研究分析用系统适用性溶液。本研究中推测的聚合物杂质结构对头孢克洛原料及其制剂的杂质谱研究及质量控制有重要参考意义。

柱上隔离开关不同镀银层参数的导电及磨损性能实验研究

为提高柱上隔离开关的导电和耐摩抗磨能力,行业目前主要采用在其接触部位进行镀银处理。但镀银层厚度、粗糙度和硬度对柱上隔离开关的导电性、磨损度的影响缺乏研究,亟需给出更加合理的设计标准。本文以GW-9系列柱上隔离开关为研究对象,通过投制试验样件,研究了镀银层厚度、粗糙度、硬度及涂覆电力复合脂对其接触部位导电性及摩擦磨损性能的影响。研究结果表明:柱上隔离开关接触部位镀银能够提高接触表面的导电性和摩擦性能,镀银层的粗糙度和硬度对接触部位的导电性具有一定影响,不同镀银层厚度对接触部位导电性的影响较小,电力复合脂润滑能够显著提高隔离开关接触部位的抗磨性能。研究结果可为隔离开关电接触材料参数的标准化设计提供理论与实验依据。

柱上开关电磁辐射干扰测试技术研究

针对现有技术中柱上开关电磁辐射干扰测试能力滞后等问题,研究通过搭建电磁辐射对柱上开关干扰测试装置,通过柱上开关集合、屏蔽模块、检测模块、电磁干扰信号发生器、电压检测、电流检测、信号处理、干扰信号分析模块以及终端分析模块等实现柱上开关电磁辐射干扰测试;通过构建一种新型的改进深度学习模型,应用RBF神经网络,大大提高柱上开关电磁辐射干扰的预测精度。通过实验,这种方法提高了柱上开关电磁辐射干扰预测能力。

Egg White Protein-Bonded Columns and Their Applications

Egg white protein bonded columns were developed for HPLC. These columns can be used under aqueous mobile phase and separate various kinds of drug enantiomers. Hyphenated techniques using protein bonded columns with LC/MS and/or column switching have been recognized as integral methods in pharmaceutical research to analyze drug enantiomers. Therefore, these methods are very useful for research fields of pharmacokinetics and pharmacology.

面向输电网弹性提升的灵活控制装置配置规划

为提升电力系统弹性,确保主网应对小概率-高影响事件的能力,基于鲁棒优化理论提出主网灵活控制装置配置的规划框架,充分考虑远动开关配置下的最优线路开断(optimal transmission switch,OTS)、线路强化加固装置以及储能设施之间的最优协同作用,最大限度降低投资运行成本的同时减少由潜在极端事件造成的经济损失。首先,基于持续负荷曲线构建考虑典型日线路中断与新能源出力波动的两阶段鲁棒规划模型;然后,采用修改后的嵌套列和约束生成算法(nested column-and-constraints generation,NCCG)对模型进行求解,使用相关加速策略提升模型求解效率;最后,通过IEEE-24节点系统进行仿真分析,验证异质灵活控制装置之间的规划协同作用以及模型的有效性。

注射用盐酸头孢替安与临床常用溶剂的配伍稳定性研究

目的 考察注射用盐酸头孢替安与2种常用注射用配伍溶剂的配伍稳定性。方法考察配伍后0、2、4、8 h的溶液澄清度与颜色、渗透压摩尔浓度;并采用高效液相色谱(HPLC)测定配伍后的含量、有关物质、5-羟甲基糠醛情况;产生的主要未知杂质经柱切换的液相质谱联用(LCMS-IT-TOF)定性。结果 注射用盐酸头孢替安与常用溶剂配伍后,在室温下存放8 h,颜色变深,有关物质增加明显,产生的主要未知杂质经定性确定为聚合物杂质。结论在室温条件下,注射用盐酸头孢替安与0.9%氯化钠注射液、5%葡萄糖注射液配伍后不稳定,应立即使用。

多维气相色谱法关于混合气体检测过程中阀切换时间的研究

本文对多维气相色谱技术分析混合气体过程中的阀切换时间进行探讨,以当前典型的四阀六柱三检测器分析系统对混合气体进行检测为例,对多阀多柱分析混合气组成时各阀柱的功能及调节方法进行了分析,从而快速确定各通道的阀切换时间,优化分析过程。

柱上开关状态监测与故障诊断技术研究

针对传统柱上开关监测与故障诊断技术存在硬件设备不够完善、监测时间长、监测精度低的问题,采用储存电能电动机状态监测装置和多分类柱上开关状态故障诊断算法模型对现有方法进行了改良。构建出了具有数据采集模块、数据传输模块、数据计算模块、用户服务模块的柱上开关状态监测系统。对于所收集到的柱上开关状态监测数据进行深入的分析与计算,从而实现完善的监测硬件设备,较短的监测时间以及很高的监测精度。通过实验表明,本设计最低监测精度可达95%,在小数据量数据包最快所需监测时间只要10s。

一种系统优化转向时钟弹簧异响设计方法

在转向过程中驾驶室内时钟弹簧异响是一个在市面很多车型普遍存在且多发的问题,而问题的根本原因不仅仅是单一零件的设计失误,更是一个系统的问题,仅仅通过系统内零件各自的设计优化,很难从根本上避免异响的发生。本文从系统内各零件匹配设计入手,选取了对时钟弹簧异响影响最大的3个零件间的匹配设计方向,提出相应的优化方案及建议,通过对近年各车型的生产、售后问题持续跟踪,来验证各匹配方案的优缺点,并证明推荐方案的可实施性和有效性。

在线柱切换二维液相色谱法测定市售液态乳品中维生素D3的含量

采用双梯度中心切割液相色谱分离系统,建立在线柱切换二维高效液相色谱法测定液态乳品中维生素D3含量的方法。样品经过60℃皂化1h、萃取浓缩后进样,一维色谱采用C8色谱柱初步分离,确定维生素D3的中心切割时间,经捕获柱捕集维生素D3馏分转入二维色谱PAH柱进一步分离。一维梯度以甲醇-水体系作为流动相,流速为0.8 mL/min,二维梯度以甲醇-乙腈体系作为流动相,流速为0.3mL/min,检测波长为264nm。维生素D3在0.1~0.8mg/L范围内的相关系数r为0.9993;回收率为91.2%~98.2%;相对标准偏差为1.6%~3.8%(n=6);将该方法对实际样品的检测结果与国标法的测定结果进行对比,结果表明其准确度和稳定性均优于标准方法。本方法操作简便,回收率高,重现性好,可用于市售液态乳品中维生素D3的检测。

Determination of trace inorganic anions in anionic surfactants by single-pump column-switching ion chromatography

An ion chromatography method has been proposed for the determination of three common inorganic anions（chloride,nitrate and sulfate） in anionic surfactants using a single pump system.The new system consists of an ion exclusion column,a concentrator column,and an anion exchange column connected in series via two 6-ports valves in a Dionex ICS-2000 ion chromatograph.The valves were switched several times for removing surfactants,concentrating and separating the three anions.The chromatographic conditions were optimized.Detection limits（S/N = 3） were in the range of 0.10-0.68μg/L.The relative standard deviations（RSDs） of peak area were less than 4.6%.The recoveries were in the range of 84.1-112.6%.

离子色谱柱切换在线前处理法同时测定皮革及织物中的三价铬与六价铬离子

采用一根NG1反相色谱柱作为前处理柱在线去除样品中的水溶性有机基质,建立了离子色谱柱切换技术同时测定CrⅢ与CrⅥ的方法。进样前,先将待测样品水溶液与一定浓度的乙二胺四乙酸（EDTA）溶液充分反应,使其中的CrⅢ络合生成阴离子产物,该阴离子产物在可见光范围内有较强吸收;进样后,样品中的离子经前处理柱分离后被收集在2 mL接收环内,通过柱切换技术,淋洗液将接收环内的离子带至阴离子分析柱中分离,CrⅥ与1,5-二苯卡巴肼（DPC）溶液进行衍生化反应后与CrⅢ的EDTA络合物在同一波长下有较强吸收,由此可完成对两种离子的同波长测定。在优化的实验条件下,CrⅢ与CrⅥ的线性范围分别为0.3~10 mg/L（r=0.9991）,0.05~2 mg/L（r=0.9992）,检出限分别为80.78和6.67μg/L（信噪比S/N=3）,将3 mg/L CrⅢ与0.3 mg/L CrⅥ标准溶液连续进样6次,得到的色谱保留时间及峰面积相对标准偏差均小于3%;将本方法应用于皮革中CrⅢ与CrⅥ的检测,加标回收率为88.7%~108.5%。实验结果表明,本方法用于皮革及织物中铬离子的检测,具有快速、灵敏、选择性好等优点。

柱切换HPLC法同时测定人血浆中阿莫西林和克拉维酸浓度

柱切换 HPL C法同时测定人血浆中阿莫西林和克拉维酸浓度。血浆样品加头孢羟氨苄为内标 ,用乙腈沉淀蛋白及二氯甲烷反洗 ,水相进样后经在线净化 ,由流动相洗脱切入 C1 8分析柱进行分离测定。阿莫西林和克拉维酸线性范围分别为 0 .5～ 16和 0 .2 5～ 5 μg/ ml,净化回收率分别为 92 .8%～ 95 .2 %和 77.3%～80 .8% ,方法回收率分别为 94 .0 %～ 96 .1%和 88.9%～ 97.6 % ,日内 RSD分别为 0 .6 3%～ 1.6 1%和 1.4 5 %～ 2 .94 % ,日间 RSD2 .30 %～ 5 .31%和 5 .0 2 %～ 7.37%。本法准确可靠 。