粒子束接口液相色谱—质谱应用

粒子束接口（ＢＰＩ，Ｐａｒｔｉｃｌｅ Ｂｅａｍ Ｉｎｔｅｒｆａｃｅ）是几种实现液相色谱－质谱联用的技术之一。本文结合ＦｉｎｎｉｇａｎＭＡＴＳＳＱ７１０质谱仪及其粒子束接口与Ｗａｔｅｒｓ液相色谱泵联用和近年来有关文献对仪器结构、分析条件选择、应用等方面进行讨论。     

人尿中的刺激剂Mesocarb的HPLC－ES／MS分析

利用ＨＰＬＣ－ＥＳ／ＭＳ（高效液相色谱／电喷雾接口／质谱）联用技术，对国际奥委会规定禁用的药物精神刺激剂Ｍｅｓｏｃａｒｂ的标准品和阳性尿进行了分析实验。通过对分离条件、离子化条件等的选择，建立了一个可靠的Ｍｅｓｏｃａｒｂ的检测方法。     

液相色谱—气相色谱联用技术的发展

液相色谱—气相色谱联用技术的发展姜燕（山西经济管理学院城建系太原０３０００６）关键词液相色谱毛细管气相色谱联用接口液相色谱和气相色谱联用技术（ＬＣ／ＧＣ）是一项新型多维色谱技术［１］。它兼有ＬＣ的高选择性和ＧＣ的高效率及高灵敏度,对复杂有机试样有较强...     

HPLC与AAS,AFS联用技术在元素化学形态分析中的应用

本文介绍了高效液相色谱与原子吸收光谱、原子荧光光谱的联用技术及其应用于元素化学形态分析的现状、前景及存在问题。着重论述了用于元素形态分析的高效液相色谱分离方法及联用接口。     

《高速液相色谱-质谱联用》

高速液相色谱—质谱联用是色—质联用的一个新动向,这种联用比起气相色谱—质谱对样品的适用范围要更广些,特别是对难气化、易分解的大分子的试样更具优越性。本文主要介绍高速液相色谱—质谱联用的各种接口装置,其中包括二种类型——分离溶剂与不分离溶剂联用的五种不同方式,并比较了各种联用的优缺点。     

高效液相色谱电感耦合等离子体质谱联用技术HPLC-ICP-MS进展

综述了高效液相色谱电感耦合等离子体质谱联用技术的发展情况。简要介绍了该联用技术的应用概况、接口及主要困难。引用参考文献91篇。     

分离/分析联用技术与仪器

综合评述了各种分离/分析联用技术与仪器。重点论述的内容包括:气相色谱/质谱法各种类型接口和仪器,液相色谱/质谱法联用的困难和现有的六种接口,实现色谱/红外光谱法联用的各种方法和仪器,现有三种质谱/质谱联用仪器产品的型式,以及以上各种联用技术与仪器的发展趋势。此外,还对分离/分析联用技术和仪器的名词术语和符号的统一命名法提出了具体建议。     

色谱联用技术

本书对色谱联用技术中所涉及到的仪器,如质谱、傅里叶变换红外光谱、原子光谱、核磁共振等仪器的构件及谱图作了简要介绍,并在此基础上逐一介绍了各种联用技术:气相色谱-质谱联用,液相色谱-质谱联用,色谱-傅里叶红外光谱联用,色谱-原子光谱联用,色谱-ICP／MS联用,色谱-核磁共振谱联用,以及色谱-色谱联用。书中不仅介绍这些联用技术系统组成、接口、工作原理等,还举实例介绍其实际应用。读者对象:色谱分析人员、大专院校师生。     

液相色谱/质谱联用中的热喷雾接口

热喷雾接口是一种新型液相色谱/质谱联用接口。本文介绍热喷雾接口的结构、工作原理、操作方法和谱图特征.通过与其他接口的比较,说明其效率、方法的灵敏度和优缺点,热喷雾接口最适合于难汽化和热不稳定化合物,尤其是生物样品分析.     

1200L液相色谱／四极杆串联质谱联用仪

美国瓦里安公司经过半个多世纪的发展 ,已成为国际上主要的科学仪器生产、供应商。其产品广泛应用于生命科学、环境分析、石油化工、卫生检疫、公安法医等众多应用领域。作为ＭＳ/ＭＳ技术的先驱 ,瓦里安公司一直致力于提高仪器性价比的研究和开发。 2 0 0 2年瓦里安公司又在 2 0 0 2年匹兹堡国际仪器展览会上推出了价格适中、配置灵活、性能稳定、灵敏度高、应用广泛、自动化程度高的液相色谱 / /四极杆质谱联用仪 ,该液质联用仪可升级为液相色谱 /三级四极杆串联质谱仪。通过调换色质接口 ,该质谱仪还可以与气相色谱仪联用 ,是目前市场上…     

Determination of polychlorinated dibenzo-p-dioxins,dibenzofurans, and biphenyls by gas chromatography/mass spectrometry in the negative chemical ionization mode with different reagent gases

Reagent gases that are used in mass spectrometry in the NCI mode for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are discussed. Ion-molecule reactions and respective characteristic ions that form while using reagent gases (CH(4), O(2), i-C(4)H(10), NH(3), H(2), He, Ar, Xe, SF(6)) or gas mixtures (CH(4)/O(2), Ar/CH(4), CH(4)/H(2)O, Ar/O(2), i-C(4)H(10)/CH(2)Cl(2)/O(2)) are reviewed. It is shown that only CH(4), O(2), CH(4)/O(2), and CH(4)/N(2)O are widely used and well studied, even though-in the case of these reagent gases-there are contradictions between the publications of various authors. Such reagent gases as NH(3) and He are not well studied, but further investigations of their use for the determination of organochlorine pollutants could be of interest. The possibilities of more sensitive and selective determination of PCDDs, PCDFs, and PCBs are discussed.     

Cryo-X-ray analysis-A novel tool to better understand the physicochemical reactions at the bioglass/biological fluid interface

The present study deals with the short-term physicochemical reactions at the interface between bioactive glass particles [55SiO(2)-20CaO-9P(2)O(5)-12Na(2)O-4MgO. mol%] and biological fluid (Dulbecco Modified Eagle's Medium (DMEM)). The physicochemical reactions within the interface are characterized by scanning transmission electron microscopy (TEM) (STEM) associated with Energy-dispersive X-ray spectroscopy (EDXS). Microanalysis of diffusible ions such as sodium, potassium, or oxygen requires a special care. In the present investigation the cryo-technique was adopted as a suitable tool for the specimen preparation and characterization. Cryosectioning is essential for preserving the native distribution of ions so that meaningful information about the local concentrations can be obtained by elemental microanalysis. The bioglass particles immersed in biological fluid for 24 h revealed five reaction stages: (i) dealkalization of the surface by cationic exchange (Na(+), Ca(2+) with H(+) or H(3)O(+)); (ii) loss of soluble silica in the form of Si(OH)(4) to the solution resulting from the breakdown of Si--O--Si bonds (iii); repolymerization of Si(OH)(4) leading to condensation of SiO(2)); (iv) migration of Ca(2+) and PO(4) (3-) to the surface through the SiO(2)-rich layer to form CaO-P(2)O(5) film; (v) crystallization of the amorphous CaO-P(2)O(5) by incorporating OH-- or CO(3) (2-) anions with the formation of three different surface layers on the bioactive glass periphery. The thickness of each layer is approximately 300 nm and from the inner part to the periphery they consist of Si--OH, which permits the diffusion of Ca(2+) and PO(4) (3-) ions and the formation of the middle Ca--P layer, and finally the outer layer composed of Na--O, which acts as an ion exchange layer between Na(+) ions and H(+) or H(3)O(+) from the solution.     

Characterization of micellar film morphologies of semifluorinated block copolymers by AFM

The micellar morphologies of well-defined amphiphilic block copolymers composed of 1H,1H-dihydroperfluorooctyl methacrylate (FOMA) and ethylene oxide (EO) blocks with different chain lengths were effectively investigated by using tapping mode-atomic force microscopy (TM-AFM). By spin-casting chloroform solutions, well-ordered spherical micellar films could be obtained for poly(FOMA(10k)-b-EO(10k)) and poly(FOMA(20k)-b-EO(20k)) copolymers. The atomic force microscopy (AFM) height and phase image analysis indicated that dark regions of the micelles corresponded to PEO blocks and the light regions were for PFOMA blocks. The spherical micelles with PEO corona and PFOMA core were also identified by transmission electron microscopy (TEM) and X-ray photoelectron spectrometer (XPS) analysis. The core diameters of the block-copolymer aggregates were 20nm for poly(FOMA(10k)-b-EO(10k)) and 30nm for poly(FOMA(20k)-b-EO(20k)) by TM-AFM, whereas slightly lower values of 17 and 26nm were obtained from TEM. A detailed study on the inverted morphological change observed in the micelles films after annealing above glass transition temperature (T(g)) was also presented.     

数控强力切削中伺服系统对极限切削宽度的影响

针对数控强力切削中颤振问题,建立了包含切削过程颤振环节的数控强力切削伺服系统数学模型。对模型的理论分析、计算机仿真及正交试验验证表明:增大位置环增益KPP可以提高机床快速跟踪性能,减小速度环积分时间常数τs能迅速消除系统静差,但极限切削宽度blim会随之而下降;过大或过小的速度环增益KPS都会导致blim下;优化调节伺服系统KPP,τs和KPS可提高系统的动、静态特性及blim。正交实验优化伺服系统参数方法简单可行,能有效地提高切削系统稳定性和极限切削宽度,适用于重型机床的数控强力切削。     

多元掺杂LaGaO_3基稀土复合氧化物的制备与导电性能

采用改进的固相反应法合成了锶、镁与铁或钴多元掺杂的LaGaO3基稀土复合氧化物La0.8Sr0.2Ga0.72Mg0.20Fe0.08O2.8(LSGMF)和La0.8Sr0.2Ga0.72Mgo.20Co0.08O2.8(LSGMC),利用EDS、XRD及SEM等方法对LSGMF和LSGMC的化学成分、物相组成及显微组织等进行了分析;采用直流四端子法测量了两者在350～850℃温度区间的电导率.结果表明:经1 400℃烧结后,LSGMF和LSGMC均形成单一正交钙钛矿结构;两者除含少量钙外,不舍其他杂质元素;在测试温度范围,材料的电导率与温度的关系分区间符合Arrhenius方程,在较低温阶段(350～500℃)具有较低的导电活化能(Ea<0.3 eV);与仅用锶、镁双掺杂的LSGM相比,LSGMF和LSGMC具有较高的电导率.     

X80高屈强比管线钢性能分析与管道安全性预测

测出X80等5种材料常规机械性能及名义应力屈强比σs/σb和真实应力屈强比Ss/Sb。比较发现Ss/Sb较σs/σb小13%,表明高强度、高屈强比X80钢屈服后塑性变形裕度仍较大。还测出材料静力韧度、冲击韧性及断裂δR阻力曲线,并应用于X80钢管线安全性预测,可以认为,高屈强比对结构安全性的影响并非如通常认为的那么严重。最后讨论了屈强比对硬化指数n的影响。     

原位自生20%TiC/Fe和20%(TiW)C/Fe复合材料的组织与性能

用原位自生法制备了20％TiC/Fe复合材料,并以W替代部分Ti制备了两种20％(TiW)C／Fe复合材料,研究了它们的显微组织与性能。结果表明：在20％TiC／Fe和20％(Ti0．8W0.2)C／Fe复合材料中,TiC和(TiW)C分别是两种材料中唯一的第二相,它们呈枝晶、方块和条形等多种形态。在20％TiC／Fe中．由于TiC与铁熔体的密度相差较大,出现了第二相的分布不均现象。在20％(Ti0.7W0.3)C／Fe复合材料中,(TiW)C相是唯一的第二相,它呈细小等轴粒状和条状两种形态,均匀分布于基体中,它的硬度与耐磨性明显好于前两种复合材料。     

Oscosurvismeter,A New Instrument for Osmotic Pressure,Conductance, Viscosity,and Surface Tension Measurements of Liquid Solutions of Chemical Substances

Abstract

The Oscosurvismeter is made of borosil glass material for measuring osmotic pressure (π), specific conductance (κ), viscosity (η), and surface tension (γ) of solutions. Solutions of different strengths are taken in two cells/compartments, partitioned by a semi‐permeable membrane (SPM). A concentration gradient makes the solvent move towards the concentrated solution to establish an equilibrium; this measures osmotic pressure (π). The Oscosurvismeter saves time and materials, and enhances accuracy and precision in measurements; the instrument consists of six parts: (1) survismeter; (2) osmometer; (3) electrode; (4) metallic clamp; (5) semipermeable membrane (SPM); and (6) high potential metallic springs. High accuracy data are noted with the instrument.     

Cathodoluminescence study of semiconductor oxide micro- and nanostructures grown by vapor deposition

Nano- and microstructures of SnO(2), In(2)O(3) and ZnO have been grown during thermal treatment of compacted powders under argon flow. Indium-doped SnO(2) tube-shaped structures with rectangular cross-section are obtained by adding a fraction of In(2)O(3) to the starting SnO(2) powder. In-rich nanoislands were found to grow on some edges of the tubes. ZnO nanostructures doped with Sn or Eu were grown by adding SnO(2) and Eu(2)O(3) powder, respectively, to the ZnO precursor powder. All the samples have been characterized by the emissive and cathodoluminescence (CL) modes of scanning electron microscopy. CL images from SnO(2):In and In(2)O(3):Sn tubes and islands show a higher emission from the Sn-rich structures related to oxygen deficiency. CL of doped ZnO enables to detect the presence of dopant in specific regions or structures. CL appears to be a useful technique to study optical and electronic properties of semiconductor oxide nanostructures.     

A study on conformational changes by electron charges in viologen single molecules by using STM

The topography of self-assembled viologen derivatives (VC(8)SH, VC(10)SH, HSC(8)VC(8)SH, and HSC(10)VC(10)SH) molecules on an octanethiol (C(8)) self-assembled monolayer (SAM) modified gold surface was measured using ultrahigh-vacuum scanning tunneling microscopy (UHV-STM). We demonstrate here a novel matrix SAM appropriate for isolation of the viologen molecules. The C(8) was used for a matrix SAM, in which the VC(8)SH, VC(10)SH, HSC(8)VC(8)SH, and HSC(10)VC(10)SH were inserted at molecular lattice defects. The isolated single molecules of viologen derivatives inserted in the matrix SAM were observed as protrusions in STM topography using a constant current mode. We measured the topographic heights (VC(8)SH: 1.53nm, VC(10)SH: 2.01nm, HSC(8)VC(8)SH: 2.71nm, and HSC(10)VC(10)SH: 3.3nm) of the molecular protrusions using STM. Also, changes in the central axis of viologen molecules were observed as VC(8)SH (0.5-0.73nm), VC(10)SH (0.4-0.74nm), HSC(8)VC(8)SH (0.67-0.84nm), and HSC(10)VC(10)SH (0.67-0.99nm), respectively.