X射线荧光光谱法测定镀铝锌板耐指纹膜质量

提出镀铝锌板耐指纹膜质量的X射线荧光光谱法,对样品的制备条件、仪器工作条件等进行了分析研究,建立了耐指纹膜中元素Cr和Zr的X荧光强度与标准样品膜质量的相关曲线,线性相关系数分别为0.9997和0.9999,相对标准偏差(RSD,n=10)分别为0.69%和0.67%,适用于生产应用.     

一种溶解氧敏感膜荧光发射效率光谱检测系统的研制

荧光猝灭法是快速测量污水、地表水以及渔业养殖水环境中溶解氧含量的先进技术之一,氧敏感膜是荧光猝灭法检测技术的核心,高荧光发射效率的氧敏感膜具有灵敏度高、特异性强、信噪比高的优点,检测结果更为准确。高效率是优选氧敏感膜的依据,也是溶解氧检测元器件、检测电路和检测光路优化设计的关键。现有溶解氧荧光检测装置中未有对氧敏感膜进行质量评估的标准方法,基于对已有传感器探头光路和电路的研究,该研究分析了全波段的荧光发射效率,选用大功率氙灯作为激发光源,基于连续单波长逐级扫描进行单色分光,构建了氧敏感膜的激发光-荧光光谱扫描装置,然后通过扫描测定氧敏感膜的激发光光谱和荧光光谱,提出并建立了荧光发射效率计算方法,提出的方法能客观地评估荧光发射能力,准确寻找最佳激发波长。为验证该方法的可行性,对来自国内外的多个氧敏感膜样品进行了实验测定,测试结果表明：单张氧敏感膜荧光发射效率随波长变化,呈多峰分布,同一型号的样品荧光效率曲线相似,但荧光发射效率差异较大,同一激发波长下荧光发射效率最大者较最小者高出14.5%,三张氧敏感膜的最大峰值波长均不同,分别为：401,543和435 nm,但发射峰值波长均为650 nm;不同型号的氧敏感膜相比较,最大荧光发射效率可相差1～2个数量级;实测传感器中使用的激发波长,其所选用的激发波长并非最大发射峰值波长,其荧光发射效率仅为最大荧光发射效率的1/2,表明传感器光源可以进一步优化选型。综上所述,本文建立了一种溶解氧敏感膜荧光发射效率检测系统,提出了以荧光发射效率评估氧敏感膜的方法,并开展了相关实验测定。本文工作可望用于新型氧敏感膜材料、工艺的研究及传感器优化设计与制造。     

荧光分子印迹膜选择性检测7-氨基-4-甲基香豆素

合成了以7-氨基-4-甲基香豆素为模板分子,聚偏氟乙烯微孔滤膜为支撑介质的分子印迹复合膜.采用荧光光度法,研究了荧光分子印迹膜的吸附动力学、吸附容量和选择性吸附性能.研究表明,该印迹膜对模板分子具有良好的识别功能.     

基于改进标准加入法的碳酸饮料中防腐剂和甜味剂高通量筛查分析

利用正交设计分别配制含有三种防腐剂、四种甜味剂的模拟水样,采用核独立成分分析（KICA）处理模拟水样与加入不同含量标准品的饮料样品的紫外光谱(UV)数据,得到其中待测添加剂或背景成分的UV轮廓的独立组分(IC)信息,以IC的系数矩阵进行支持向量回归（SVR）分析,建立模拟样品中防腐剂与甜味剂的UV-KICA-SVR预测模型。添加不同含量水平添加剂的碳酸饮料样品,采用KICA处理其测试得到的UV光谱数据,得到与添加剂对应的IC信息及量,加入量与预测量线性回归方程截距即为饮料中添加剂含量。利用化学计量学“盲源信号分离”方法提取饮料样品中的待测添加剂IC信息与样品基质信息,利用SVR对解析得到的IC信号回归分析建模,改进传统单一组分测定的标准加入法,建立了碳酸饮料样品中防腐剂和甜味剂高通量筛查分析的新方法。方法用于测定碳酸饮料中山梨酸钾,苯甲酸钠、对羟基苯甲酸甲酯钠三种防腐剂与糖精钠、安赛蜜,阿斯巴甜和甘草酸铵四种甜味剂含量,检测限(LOD)为0.2～1.0 mg·L-1,测定结果与传统的色谱方法相当。     

A High Efficiency,High Throughput Unipolar Aerosol Charger for Nanoparticles

A novel aerosol charger has been developed, which has high efficiency and high throughput especially for nanometer particles in the size range of 3–50nm. Unipolar charging with high ion concentration and long charging time is used to obtain the high charging efficiency. High throughput is achieved by reducing particle loss within the charger. This is accomplished by directing ion flow and aerosol flow in the same direction and by the use of sheath air flow. The charger configuration is of a longitudinal design – the direction of aerosol stream and ion stream are flowing parallel along the longitudinal axis of the charger. The charger consists of four sections: the inlet zone, the ion production zone, the unipolar charging zone, and the exit zone. In the inlet and ion production zones, unipolar ions are generated using Po²¹⁰ radioactive sources with an electric field designed to separate the positive and negative ions, and to focus the selected unipolar ions into the core region of the charger. The ions with the selected polarity is then attracted to the charging zone by an uniform electric field created by a series of ring electrodes applied with a linear ramped voltage. Aerosol entering the charger is sheathed with clean gas flow in order to keep the aerosol in the core region. A novel exit design with a reversed electric field is incorporated in order to minimize the charged particles loss. The performance of the charger is first evaluated using computer simulation and then constructed for experimental validation. Experiment data have demonstrated that the charger achieves 90% and 95% charged-particles penetration efficiency and with 22% and 48% extrinsic charging efficiency at 3 and 5nm particle sizes, respectively. These performance data represent significant improvement, over a factor of 10, compared with the existing chargers.     

Achieving High Data Throughput in Research Networks

After less than a year of operation ,the BaBar experiment at SLAC has collected almost 100 million particle collision events in a database approaching 165TB.Around 20 TB of data has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon,France,and around 40TB of simulated data has been imported from the Lawrence Livermore National Laboratory(LLNL),BaBar Collaborators plan to double data collection each year and export a third of the data to IN2P3.So within a few years the SLAC OC3 (155Mbps) connection will be fully utilized by file transfer to France alone.Upgrades to infrastructure is essential and detailed understanding of performance issues and the requirements for reliable high throughput transfers is critical.In this talk results from active and passive monitoring and direct measurements of throughput will be reviewed.Methods for achieving the ambitious requirements will be discussed.     

高含量铷化探样品中镍的XRF法测定

对于化探样品中 Rb元素含量超高的样品 ,通过拓宽标准样品的含量范围 ,利用 X射线荧光光谱仪 ,选择既有准确分析值 ,又能代表样品元素含量范围的标准样品 ,经回归计算 ,测得校准曲线 ,对 Rb的含量在 2× 10 -6— 132 0× 10 -6的变化范围内 ,准确测定 Ni的含量     

氢化物-原子荧光光谱法测定高纯铅中硒

本文研究了氢化物－原子荧光光普法（HGAFS）测定高纯铅中微量杂质硒，考察了最佳测定条件及共存元素对测定结果的影响，本方法操作简便，快速。结果准确，相对标准偏差小于10％，加标回收率为86．3％－91．8％。     

Chip-Based Microwave Photonic Payload Repeater for High Throughput Satellites

High-throughput satellite (HTS) is an ideal way to realize cross-regional massive, multifaceted digital exchange services, and it requires a signal processing module that can be massively multiplexed and has high flexibility. Due to the limitations of the frequency characteristics, microwave integrated circuits are difficult to meet this requirement. One solution to this problem is photonic integrated circuits (PICs). However, full-size PIC satellite payloads containing main optoelectronic components are extremely challenging to implement on monolithic or hybrid integrated platforms. Here, the study demonstrates a hybrid integrated on-chip microwave-photonic satellite repeater with large-scale multiplexing potential and high flexibility. This is a demonstration of a hybrid integration of a InP/Si3N4 external cavity laser, arrayed InP modulators, and semiconductor optical amplifiers (SOAs), as well as multifunctional Si3N4 signal processors, to fulfill a 1 × 4 Ka-band repeater module with on-chip arrayed frequency down-conversion and outstanding narrowband photonic channelization. When combined with the full-chip photonic RF repeater, broadband, highly integrated, and cost-effective communications satellite payloads will become realizable more quickly in the near future.     

依诺沙星的荧光熄灭法测定

基于依诺沙星对十二烷基苯磺酸钠的荧光具有猝灭的特性,建立了一种测定依诺沙星的新方法。在pH2.00的磷酸缓冲溶液中,十二烷基苯磺酸钠的激发波长为283nm,发射波长为326nm,依诺沙星的浓度在0—8.1μg/mL范围内与其荧光强度呈良好的线性关系,检出限为0.016μg/mL,方法的相对标准偏差为1.17%。本法灵敏度高、选择性好,用于制剂中依诺沙星的含量测定,结果令人满意。     

Development of Two Innovative 96-Microwell-Based Spectrophotometric Assays with High Throughput for Determination of Fluoroquinolone Antibiotics in their Pharmaceutical Formulations

Journal of Applied Spectroscopy - Fluoroquinolone antibiotics (FQAs) have broad-spectrum antibacterial activity, high potency, variable indications, and excellent pharmacokinetic profi les. Many...     

Determination of Interatomic Potentials for the X0(+), A0(+), and B1 States of HgKr from Fluorescence and Excitation Spectra

We present an analysis of the A0(+)(6(3)P(1))-->X0(+)(6(1)S(0)) bound-bound and bound-free fluorescence spectrum, and of the A0(+)(6(3)P(1))<--X0(+)(6(1)S(0)) and B1(6(3)P(1))<--X0(+)(6(1)S(0)) bound-bound excitation spectrum of the HgKr van der Waals molecule. The A-->X fluorescence spectrum, which was observed for the first time, as well as the excitation spectra were recorded using a pulsed supersonic molecular beam crossed with a pulsed dye laser beam. An analysis of the A(v')<--X(v"), B(v')<--X(v"), and A(v'=8)-->X(v") bound-bound bands indicates that a Morse function combined with a long-range approximation represents the interatomic potential energy curve of the A, B, and X states below the dissociation limit. In the simulation of the A(v'=8)-->X bound-free spectrum the Morse, Lennard-Jones (n-6), and Maitland-Smith (n(0), n(1)) functions were tested, and the Maitland-Smith (11.39, 10.50) potential was found to be a good representation of the repulsive part of the X-state PE curve above the dissociation limit, over the internuclear separation range R=2.85-3.55 ?. The spectroscopic characteristics for the A, B, and X states obtained in this work are compared with other available experimental and theoretical results. Copyright 2001 Academic Press.     

Stability in High Dimensional Steep Repelling Potentials

The appearance of elliptic periodic orbits in families of n-dimensional smooth repelling billiard-like potentials that are arbitrarily steep and limit to Sinai billiards is established for any finite n. For typical potentials, the stability regions in the parameter space scale as a power-law in 1/n and in the steepness parameter. Thus, it is shown that even though these systems have a uniformly hyperbolic (albeit singular) limit, the ergodicity of this limit system is destroyed in the more realistic smooth setting. The considered example is highly symmetric and is not directly linked to the smooth many particle problem. Nonetheless, the possibility of explicitly constructing stable motion in smooth n degrees of freedom systems limiting to strictly dispersing billiards is now established.     

Fluorescence Study of the Membrane Effects of Aggregated Lysozyme

The last decade has seen unprecedented upsurge of interest in the structural and toxic properties of particular type of protein aggregates, amyloid fibrils, associated with a number of pathological states. In the present study fluorescence spectroscopy technique has been employed to gain further insight into the membrane-related mechanisms of amyloid toxicity. To this end, erythrocyte model system composed of liposomes and hemoglobin was subjected to the action of oligomeric and fibrillar lysozyme. Acrylamide quenching of lysozyme fluorescence showed that solvent accessibility of Trp₆₂ and Trp₁₀₈ increases upon the protein fibrillization. Resonance energy transfer measurements suggested the possibility of direct complexation between hemoglobin and aggregated lysozyme. Using the novel squaraine dye SQ-1 it was demonstrated that aggregated lysozyme is capable of inhibiting lipid peroxidation processes. Fluorescent probes pyrene, Prodan and diphenylhexatriene were employed to characterize the membrane-modifying properties of hemoglobin and lysozyme. Both oligomeric and fibrillar forms of lysozyme were found to exert condensing influence on lipid bilayer structure, with the membrane effects of fibrils being less amenable to modulation by hemoglobin.     

On the Free Energy of a Gaussian Membrane Model with External Potentials

We consider a class of d-dimensional Gaussian lattice field which is known as a model of semi-flexible membrane. We study the free energy of the model with external potentials and show the following:     

Review of Fluorescence Suppression Techniques in Raman Spectroscopy

Abstract

Raman spectroscopy is an important and powerful technique for analyzing the chemical composition of biological or nonbiological samples in many fields. A serious challenge frequently encountered in Raman measurements arises from the existence of the concurrent fluorescence background. The fluorescence intensity is normally several orders of magnitude larger than the Raman scattering signal, especially in biological samples. Such fluorescence background must be suppressed in order to obtain accurate Raman spectra. Several different techniques have been explored for this purpose. These techniques could be generally grouped into time-domain, frequency-domain, wavelength-domain, and computational methods in addition to various Raman enhancement techniques and other unconventional methods. This review briefly describes the fundamental principles of each group of methods, reports the most recent advances, and makes comparison across those major categories of techniques in terms of cost and performance in a hope to guide interested readers to select proper methods for specific applications.     

Preconcentration Methods for the Analysis of Liquid Samples by X-Ray Fluorescence Techniques

Abstract

This article gives an overview of the state-of-the-art of multi-element and single-element preconcentration procedures prior to X-ray fluorescence (XRF) analysis of liquid samples. Many of these preconcentration methods were developed long ago and the purpose of this review is to present some new efficient variations of these methods and new techniques extending the possibilities of XRF for liquid solutions analysis. In addition, trends and future perspectives in this domain are also commented on and discussed in the last section of the review.