Application of Capillary Electrophoretic On-Line Sequential Concentration Based on Micelle to Solvent Stacking

To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was reviewed. MSS has been coupled to sweeping FASS, FASI and normal EKI. Furthermore, multiple stacking by coupling MSS with more than one stacking method has also been reported. It is more sensitive and selective than solely used of one or two stacking methods and is very suitable for complex and trace sample analysis.

Sequential injection spectrophotometric determination of nanomolar nitrite in seawater by on-line preconcentration with HLB cartridge

The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described..An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol （volume fraction is 55%, the same below）, in turn, then eluted by an eluent containing 50% ethanol and 0.25 M（mol/dm^3） H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4 85.7 aM, and the LOD （3a） was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.

Determination of triazine herbicide residues in water samples by on-line sweeping concentration in micellar electrokinetic chromatography

A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.

On-line Sweeping Sample Concentration in Micellar Electrokinetic Chromatography with Enhanced Sensitivity for the Deter-mination of Carbamazepine in Human Serum

A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodiode array detection. Under the optimal conditions, the calibration curve was linear over a range of 0.5-40μg·mL^-1 for CBZ with a correlation coefficient of 0.998. The detection limit （S/N = 3：1） of CBZ was 0.10 μg·mL^-1. The sweeping-MEKC method has been successfully applied to the analysis of CBZ in human serum.

Reagent optimization for on-line simultaneous polarographic determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of anextremely large excess of Zn^(2+)

Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).

On-line forecasting model for zinc output based on self-tuning support vector regression and its application

An on-line forecasting model based on self-tuning support vectors regression for zinc output was put forward to maximize zinc output by adjusting operational parameters in the process of imperial smelting furnace. In this model, the mathematical model of support vector regression was converted into the same format as support vector machine for classification. Then a simplified sequential minimal optimization for classification was applied to train the regression coefficient vector α- α* and threshold b. Sequentially penalty parameter C was tuned dynamically through forecasting result during the training process. Finally, an on-line forecasting algorithm for zinc output was proposed. The simulation result shows that in spite of a relatively small industrial data set, the effective error is less than 10% with a remarkable performance of real time. The model was applied to the optimization operation and fault diagnosis system for imperial smelting furnace.

中医体质分型对全麻诱导时七氟醚MAC值的影响

目的:探讨气管插管全麻诱导时,在常见的四种中医体质分型患者中,吸入七氟醚使意识消失的最低肺泡有效浓度的半数有效浓度(EC_(50))的差异。方法:研究纳入80例拟择期行气管插管全麻手术患者,根据《中医体质分类与判定》标准分为平和质(A组)、血瘀质(B组)、阴虚质(C组)、阳虚质(D组)共四组,每组20例。以吸入麻醉药七氟醚诱导麻醉,使患者意识消失,设定起始七氟醚的呼气末浓度为1.72%,并计算出5个阶梯的七氟醚呼吸末浓度值,分别为0.84%、1.21%、1.72%、2.45%和3.50%,最终用序贯法测定患者意识消失时七氟醚最低肺泡浓度的EC_(50)。结果:四组病人意识消失时七氟醚EC_(50)及对应的95%可信区间(CI)分别是:A组EC_(50)为2.37%(95%CI:1.97%~2.85%);B组EC_(50)为2.21%(95%CI:1.88%~2.58%):C组EC_(50)为2.83%(95%CI:2.63%~3.03%);D组EC_(50)为1.85%(95%CI:1.57%~2.18%)。结论:七氟醚最低肺泡有效浓度在不同中医体质患者中的存在一定差异性,阳虚患者七氟醚EC_(50)比阴虚患者明显降低。

基于序关系分析法和模糊综合评价法的家用雾化制氧机设计

为提升家用雾化制氧机的用户体验及满意度,提出结合用户体验模型,采用半结构化访谈方式归纳用户需求并建立评价层级体系;采用序关系分析法进行需求指标权重计算及优度排序;通过功能分析系统技术(Function Analysis System Technique,FAST)功能树获取产品功能要素,指导设计方案输出;采用模糊综合评价(Fuzzy Comprehensive Evaluation,FCE)法对产品设计方案进行用户满意度评价。研究结果表明:基于序关系分析法和FCE法设计的家用雾化制氧机具有较高的用户满意度,设计方法的集成提升了用户需求获取与方案评价环节的效率及科学性,可为同类产品的创新设计提供参考。

多能互补发电系统电/热/氢储能容量协调优化配置

针对无常规电源支撑的风-光-热-储-氢多能互补发电行经济性和利用率具有重要意义。该文提出一种基于全年8760 h系统,协调优化配置电/热/氢各类储能容量,对提高系统运时序生产模拟的多能互补发电系统电/热/氢储能容量协调优化配置方法,建立以系统等年值收益最大为目标,考虑系统电/热/氢能量流平衡作用、新能源利用率、外送通道容量、各类电源和储能系统运行约束的电/热/氢储能容量优化配置模型,并提出新能源弃电状态与电/热/氢储能装置的耦合运行策略;以风/光全年8760 h理论出力序列为输入,通过求解模型得到兼顾系统经济、安全和清洁性的电/热/氢储能最优配置容量。算例基于我国西北某多能互补发电系统进行仿真测试,验证所提出的全年8760 h时序生产模拟方法的有效性,量化分析系统成本和电价、储能运行策略等因素对容量配置结果的影响。

On-line solid-phase extraction using alizarin violet functionalized silica gel for determination of trace lead in environmental samples and wastewater by sequential injection spectrophotometry

Trace of Pb(Ⅱ) has been on-line separated and enriched from environmental samples and wastewater by using the self-made alizarin violet functionalized silica gel micro-column coupling with a sequential injection sampling technology. The determination is based on the color reaction of Pb(Ⅱ) with iodide and crystal violet to form an ionic association complex in the presence of polyvinyl alcohol and hydrochloric acid. The use of the microcolumn can prevent the interference of most familiar metal ions, and therefore improve the selectivity and sensitivity of this analytical technique. The proposed method was used for the determination of Pb(Ⅱ) in environmental samples and wastewater. No statistically significant difference was observed between the results determined by the present method and atomic absorption spectrometry.

罗哌卡因在老年患者全髋关节置换术中髋关节囊周围神经阻滞的半数有效浓度

目的测定全麻联合髋关节囊周围神经(PENG)阻滞用于全髋关节置换术老年患者的罗哌卡因半数有效浓度(EC_(50))。方法选择择期行全髋关节置换术的老年患者36例,男20例,女16例,年龄65~80岁,BMI 18~30 kg/m 2,ASAⅡ或Ⅲ级。在超声引导下行PENG阻滞,设定罗哌卡因容量为20 ml,浓度由序贯法确定,初始浓度为0.375%,若神经阻滞20 min后,静息NRS评分较阻滞前下降≥2分且活动时NRS评分较阻滞前下降≥3分时,则视为阻滞成功,反之则视为失败,阻滞失败则下1例患者提高1个浓度梯度,阻滞成功则下1例患者降低1个浓度梯度,相邻浓度比值为1.0∶1.2,直至出现7个拐点。采用Probit概率法计算罗哌卡因的EC_(50)及其95%可信区间(CI)。记录PENG阻滞前(阻滞前)、阻滞后20 min和术后2、6、12、24 h静息和活动(被动抬髋15°)时NRS评分,术后穿刺部位感染、血肿、神经损伤、局麻药中毒、恶心、呕吐、头晕等发生情况。结果罗哌卡因用于老年患者全髋关节置换术前行PENG阻滞的EC_(50)为0.185%(95%CI 0.154%~0.213%)。无一例患者穿刺部位感染、血肿、神经损伤、局麻药中毒并发症。结论罗哌卡因用于老年患者全髋关节置换术中PENG阻滞的EC_(50)为0.185%(95%CI 0.154%~0.213%)。

基于改进OS-ELM的电子鼻在线气体浓度检测

电子鼻是一种仿生传感系统,该设备能够同时对多种气体进行识别,因此应用在许多领域当中。气体浓度算法是电子鼻对气体定量分析时的核心部分,为了提高电子鼻浓度检测算法精度,提出一种基于在线序列极限学习机(Online Sequential-Extreme Learning Machine,OS-ELM)的预测模型。该模型通过一维卷积神经网络(One Dimen‐sional Convolutional Neural Network,1DCNN)提取特征,使用OS-ELM对气体浓度进行预测,并提出了一种改进的粒子群(Particle Swarm Optimization,PSO)算法以克服OS-ELM需人工调整模型参数的问题。由理论分析,改进的算法比传统PSO算法有更强的搜索能力。实验结果表明,所提模型对气体的预测精度上较传统的预测模型具有更高的预测精度和泛化能力。

大规模新能源基地经特高压直流送出系统中长期运行方式优化方法

大规模新能源基地经特高压直流送出是我国未来新能源消纳的重要形式,合理优化特高压直流中长期运行方式,是提高新能源基地外送消纳能力的重要基础。提出了基于时序生产模拟的大规模新能源基地经特高压直流送出系统中长期运行方式优化方法。首先,考虑生产模拟计算准确性与复杂度的要求,建立了不同类型光热电站、火电机组和储能电站的聚合运行模型;然后,考虑特高压直流运行模式、灵活调节性能和受端电网负荷调峰需求,建立了不含整数变量的特高压直流运行模型。最后,建立了以新能源最大化外送消纳为目标,考虑各类电源与特高压直流运行约束的中长期运行方式优化模型,提出了基于逐周计算的全年8760h生产模拟计算方法。算例基于含风电/光伏/光热/火电/储能的大规模新能源基地开展测试,结果表明所提出方法能够优化特高压直流年/月运行曲线,实现新能源的最大化外送消纳,计算准确性与效率能够满足工程实用性需求。

顺序注射-氢化物发生原子荧光光谱法测定铜精矿中砷

利用盐酸、硝酸和液溴分解铜精矿样品，采用顺序注射-氢化物发生原子荧光光谱法检测样品中砷含量。讨论了样品中的主元素铜和其他元素对砷的干扰及消除方法；确定了适宜的硼氢化钾浓度。提出利用仪器的顺序注射装置的稀释功能测定含砷量较高的样品，扩展了测量的范围，提高了工作效率。砷质量浓度在0．90～100μg／L范围内与荧光强度呈良好的线性关系，方法检出限为0．30μg／L。该方法用于测定铜精矿中的砷，回收率可达89．1％～109．1%，相对标准偏差小于6．0%；铜精矿的测定结果与国家标准方法比较，结果吻合。

土壤中重金属铊的分级提取形态分析法研究

以自然高铊污染土壤为样品, 对BCR标准分级提取形态分析法中争议较大的HAc和NH2OH·HCl提取剂pH、提取剂浓度和提取体系温度对土壤中相应形态Tl提取量的影响进行了研究。实验发现标准条件的HAc提取体系可有效提取土壤中可交换态的Tl, 而标准的NH2OH·HCl提取体系不能有效提取土壤中易还原态的Tl。根据实验结果, 对标准BCR法进行如下改进: NH2OH·HCl提取剂pH由2.0酸化至1.5, 提取剂浓度由0.1mol/L增至0.5 mol/L, 提取体系温度由室温(28℃)增至60℃; 其他提取条件不变。

发电厂附近大气气溶胶元素浓度的监测

用Streaker时间顺序采样器在火力发电厂附近连续收集大气气溶胶样品.这些样品在2X1.7MV串列加速器上用2.5MeV的质子进行PIXE分析,得到了大气气溶胶粗、细颗粒物中21个元素浓度及其对时间的短时变化,显示了主要污染源方向的信息.结果表明,元素Si,K,Zn和As的浓度高于北京城区冬天的水平,Br/Pb的比值为0.16(n=44),高于一般地区.

阿奇霉素治疗支原体肺炎的序贯疗法定量分析

利用室分析方法,建立了药物动力学模型,给出了静脉、口服多次用药后血药浓度,并绘制出药时曲线,分析了所给的阿奇霉素治疗支原体肺炎的序贯疗法用药方案可行性,提高了用药的依从性.

油品顺序输送管道混油浓度的数值计算

针对求解顺序输送管道混油浓度的问题，简要分析了管道在不同流态下的混油机理。依据紊流扩散理论，采用数值积分方法，编制了用于求解顺序输送管道动态运行混油段内混油浓度分布，以及管道终点截面混油浓度的计算程序。为顺序输送管道混油特性的分析预测及混油浓度的计算提供了一个实用可靠的方法。

一种检测铜精矿中砷和汞含量的新方法——高压密封微波消解—顺序注射—氢化物发生—原子荧光光谱法

利用高压密封微波消解和顺序注射—氢化物发生—原子荧光光谱两项技术建立了检测铜精矿中砷、汞含量的新方法,并通过试验确定了适宜的检测条件。研究结果表明:本方法对砷的检出限为0.02μg/L,对汞的检出限为0.05μg/L;检测铜精矿中砷、汞的含量时,砷、汞的回收率分别为94.3%～107.0%和91.0%～102.0%,检测结果相对标准偏差分别在0.93%～1.97%之间和3.11%～8.07%之间,并且检测结果与认定值和国家标准方法测定值一致。

氢化物-原子荧光光谱法连续测定锌精矿中砷、锑、铋、锡

用氢化物 原子荧光光谱法 ,一次性分解样品 ,在L 半胱氨酸存在下 ,实现了锌精矿中As、Sb、Bi、Sn的连续测定。其回收率分别为 92 .8%～ 10 5 .0 %、96 .0 %～ 10 9.3%、96 .0 %～ 111.6 %和 96 .7%～ 10 3 7% ;检出限分别为 0 .35、0 .31、0 .19和 0 .35 μg/L。用该方法分析锌精矿样品 。