Characterization of glass surfaces by electron spectroscopy

Commercial glasses typically consist of many metal oxides and the surface composition of a glass article can be very different from that of its interior due to vaporization, surface migration, etc., during fabrication. At the same time the chemical make-up of the surface is extremely important in any commercial application, directly affecting the strength and durability of the product. Analytical techniques capable of examining the surface composition have been limited, however, and classical methods of chemical analysis have never been able to supply the desired information. This paper contains a review of analytical procedures that have been used for glass surface analysis and explores the potential of several recently developed techniques. These include the Electron Microprobe, Electron Spectroscopy for Chemical Analysis (ESCA), Auger Electron Spectroscopy, Ion Scattering Spectroscopy and Secondary Ion Mass Analysis. The use of Electron Spectroscopy in the study of glass compositions common to the glass fiber industry will be explored in depth.     

Preparation and characterization of metallorganic chemical vapour deposited LixMoyOz using a single source solid precursor

Thin films of Li_xMo_yO_z have been deposited on glass substrate in a one step chemical vapour deposition using a single source solid precursor. The films were characterized using Rutherford Backscattering Spectroscopy (RBS), X-Ray Diffractometry, Scanning Electron Microscopy (SEM), Impedance Spectroscopy (IS), van der Pauw conductivity measurement and Ultraviolet-Visible Spectroscopy. Results of the characterization showed that the films are dendritic, polycrystalline and semiconducting with an optical transition energy of 3.0 eV. IS characterization gave a semicircle in the complex impedance plot. The conductivity vs. temperature plot showed a transition at 450 °C and also a hysteresis. Analysis showed the film to be mixture of phases.     

New developments in the surface analysis of solids

In both fundamental and applied surface physics, it is essential to know as much as possible about the chemical composition of the outer atomic layers of solids. Rapid progress has recently been made in the development of analytical methods which could be used in surface analysis. All utilize some type of emission (photons, electrons, atoms, molecules, ions), caused by excitation of the surface states. Both the “excitation” and emission processes must meet certain basic requirements as regards information depth, form in which the information is obtained, sensitivity, changes in the surface layer during analysis, etc. The more important of the methods that qualify, namely Auger-Electron Spectroscopy (AES), photo-Electron Spectroscopy for Chemical Analysis (ESCA) and the static method of Secondary-Ion Mass Spectrometry (SIMS), are discussed and their potentialities and limitations illustrated by characteristic examples.     

Laser nitriding investigated with Mössbauer spectroscopy

The effect of the nitrogen take‐up upon irradiation of iron or steel with excimer laser pulses in air or in nitrogen atmosphere is well established. The resulting phase compositions and nitrogen depth profiles were measured by a combination of simultaneous Conversion Electron Mössbauer Spectroscopy (CEMS), Conversion X‐ray Mössbauer Spectroscopy (CXMS), and Resonant Nuclear Reaction Analysis (RNRA) as a function of the nitrogen gas pressure during irradiation. A maximum nitrogen content and a maximum fraction of the ?-nitride was found at 0.1 MPa. This result is in accordance with hardness measurements performed by the nanoindentation technique.     

蜈蚣草孢子囊元素组成的X射线光谱分析

砷超富集植物蜈蚣草具有超强的砷吸收和富集能力,生物量大,被认为是修复砷污染土壤的理想植物材料.基于砷超富集植物蜈蚣草的植物修复技术已经推广应用到了我国20多个污染区的土壤修复实践中.目前所报道的所有蜈蚣草均具有砷超富集能力,并且该特性能够得到稳定遗传.蜈蚣草是如何通过仅仅几十个微米的孢子将这种砷超富集能力传递给下一代?...     

Synthesis of cellulose nanocrystals (CNCs) from cotton using ultrasound-assisted acid hydrolysis

This present work reports the synthesis of Cellulose nanocrystals (CNCs) from cotton using an ultrasound-assisted acid hydrolysis. Further, the synthesized CNCs was comprehensively characterized using Fourier Transform Infrared Spectroscopy (FTIR) to analyze surface functional groups and X-ray diffraction (XRD) in studying structural characteristics. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) have been used to study the thermal properties of CNCs. Morphology of CNCs was studied using a Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). The crystallite size was found to be 10–50 nm using XRD data and the average particle size to be 221 nm using PSD analysis.     

Thermal Degradation of Polysiloxane Coatings on E-Glass Fiber. A FTIR Study

Fourier Transform Infrared Spectroscopy and Thermal Analysis have been used to study the thermal and termooxidative degradation of polysiloxane coatings obtained by treating E-glass fiber with aqueous solutions of 3-chloropropyltriethoxysilane. Initial weight losses were due to polymerization of the coatings. Severe oxidative degradations were observed at temperatures above 180°C. At 550°C the residue of the coating was found to be silica with free silanol groups.     

AES and photoemission studies of Cu growth on Cr2O3

The initial growth (1–20 Å) of Cu on Cr₂O₃ at room temperature has been investigated by Auger Spectroscopy and UV photoemission spectroscopy by synchrotron radiation. Analysis of the Auger peak intensities suggests that copper is growing in a layer-by-layer mode probably with the simultaneous formation of the second and third layers.The photoemission spectra show that deposited copper grows steadily as a single copper species which does not interact strongly with the substrate.     

纳米银溶胶和微腔型光纤SERS基底的制备及其性能比较

通过化学法制备了纳米银溶胶基底和微腔型光纤表面增强拉曼散射(SERS)基底,其中光纤SERS基底的微腔结构是通过氢氟酸(H F)腐蚀得到的.实验采用湿法检测,首先将纳米银溶胶基底与罗丹明6G(R6 G)混合,找到增强效果最强时的裸光纤微腔结构,在此结构的基础上采用溶胶自组装法制备银纳米颗粒包覆的光纤SERS基底,通过控...     

X-ray radiation of poly-L-arginine hydrochloride and multilayered DNA-coatings

The aim of this work was to determine the chemical changes induced in thin films of the dry polypeptide poly-L-arginine hydrochloride and its mixture with calf thymus deoxyribonucleic acid (DNA) during 5 h of soft X-ray exposure. The physical and chemical effects of the soft X-ray irradiation were studied using X-ray Photoelectron Spectroscopy (XPS). Analysis of O1s, N1s and C1s features in XPS spectra reveals the existence of several routes of radiation-induced decomposition and shows quantitative and qualitative changes.     

温度对胶原蛋白结构影响的二维红外相关光谱的研究

采用傅立叶红外光谱法(FTIR)和二维相关分析(2D Correlation Analysis)技术研究了胶原蛋白在加热(15℃～95℃)条件下构象变化的规律.结果表明:二维相关分析能提供由温度变化引起的蛋白构象变化过程中分子结构动态变化的微观信息,为揭示胶原蛋白的结构特征和变温微扰引起的结构变化机理提供了一些有意义的实验依据和初步的理论分析.     

Soft X-ray Emission Depth Profile Analysis: SXDA

A nondestructive deep profile analytical method called Soft X-ray Emission Depth Analysis (SXDA) is developed on the basis of Soft X-ray Emission Spectroscopy (SXES). The theoretical basis, methods of calculations, apparatus and typical examples are given. All the advantages of SXES are included and in addition SXDA provides qualitative and quantitative elementary analysis, nondestructive detection of chemical bonding states is and can be used for surface layers in the depth range between 10^?3 and 3 μm. Examples of applications are taken from the fields of surface oxide investigations, catalysis, and alloy analysis.     

Poly(amidehydroxyurethane) template magnetite nanoparticles electrosynthesis: I. Electrochemical aspects and identification

A new method for the electrochemical synthesis and surface-functionalization of magnetite nanoparticles (NPs) with poly(amidehydroxyurethane) (PAmHU) is presented. Transmission Electron Microscopy shows the formation of NPs PAmHU cluster systems with individual NPs ranging in size from 6 to 42 nm. Electron Spectroscopy for Chemical Analysis, Electron Paramagnetic Resonance measurements, and X-ray Diffraction show that the electrochemically synthesized product contains NPs formed by a core-coating polymer system with an inner-core consisting of magnetite entities with crystallites dimensions within 6 to 11 nm. The resulting functionalized NPs are water-soluble and stable for months.     

Applications of ESCA to industrial chemistry

Electron Spectroscopy for Chemical Analysis (ESCA) is a new spectrotechnique which is assuming significant importance as a research tool in industrial The unique value of ESCA is its potential for providing insight into problems which are quite diverse in nature. This presentation includes direct indu of ESCA to research in catalysis, surface coatings, organic structure, qualitative and quantitative measurements of materials present at low levels and in solids amongst others.     

Thin Cu films on manganese: aes and photoemission,by synchrotron radiation,investigations

The initial growth of Cu on polycrystalline manganese at room temperature has been investigated by Auger Spectroscopy and UV-synchrotron radiation photoemission spectroscopy, for copper coverages ranging from 1 to 18 Å. By monitoring the changes of the Cu3d level, a strong intermixing at the interface has been observed. The simultaneous growth of a copper phase which is lying on top of the intermixed region has also been detected. Analysis of the Auger data indicates that copper is most probably growing in a layer-by-layer mode, with a simultaneous diffusion into the substrate. Calculations for a layer-by-layer growth model are compared with the experimental data. They support our analysis.     

Effect of guest-host interaction on the dynamics of ethylene glycol in H-ZSM5 zeolite

Dynamics of ethylene glycol (EG) adsorbed in H-ZSM5 zeolite as studied using quasielastic neutron scattering (QENS) technique is reported here. Analysis of QENS data revealed that observed dynamics correspond to isotropic rotational motion of EG. Rotational diffusion coefficient of EG adsorbed in H-ZSM5 zeolite is found to be slower compared to bulk and comparable to that of benzene adsorbed in the same host. Positron Annihilation Spectroscopy (PAS) technique is used to understand the nature of guest-host interaction and the results of both QENS and PAS are found to be consistent with each other.     

Rheological Behavior and Interaction of Polycarbonate/Barium Sulfate Composites

The effect of microsized barium sulfate (BaSO ₄ ) on the rheological properties of Polycarbonate (PC) was investigated. The composite exhibits a reduced viscosity as compared to pure PC, indicating that use of barium sulfate is a new method to enhance the mobility of PC melts. Model calculation of this behavior was carried out according to a viscosity rheological equation. Values of model parameters were obtained and discussed. Other rheological properties were also determined, including frequency dependence of storage modulus and loss modulus. Analysis by Fourier Transform Infrared (FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS) shows that the barium sulfate fillers strongly interact with PC chains, with the type of interaction being determined.     

4-氨基-4'-氯二苯甲酮的合成及光谱表征

对硝基苯甲酰氯和氯苯在无水三氯化铝催化下 ,生成 4 硝基 4’ 氯二苯甲酮。以二硫化钠为还原剂 ,将其还原成重要有机中间体 4 氨基 4’ 氯二苯甲酮。通过多因素正交实验 ,确定了最佳工艺条件为 :反应温度 92℃ ,反应时间 2 5h ,4 硝基 4’ 氯二苯甲酮 :Na2 S2 =1∶1 7(mol) ,回收率为 85 80 % ,纯度为98 0 8% ,熔点 177～ 179℃。采用元素分析 ,1H ,13 C核磁共振波谱 ,红外光谱及质谱法表征了目标化合物的分子结构 ,并对化合物红外光谱吸收峰及核磁谱带进行了归属分析。阐明了质谱主要碎片离子的裂解途径。此研究可为无致癌性的禁用染料中间体替代品开发提供依据。     

Synthesis,characterization and visible-light driven photocatalysis by differently structured CdS/ZnS sandwich and core–shell nanocomposites

CdS/ZnS sandwich and core–shell nanocomposites were synthesized by a simple and modified Chemical Precipitation method under ambient conditions. The synthesized composites were characterized by XRD, SEM, TEM, EDAX and FTIR. Optical properties were analyzed by UV–vis. Spectroscopy and the photoluminescence study was done to monitor the recombination of photo-generated charge-carriers. Thermal stability of the synthesized composites was analyzed by Thermal Gravimetric Analysis (TGA). XRD revealed the formation of nanocomposites as mixed diffraction peaks were observed in the XRD pattern. SEM and TEM showed the morphology of the nanocomposites particles and their fine particle size. EDAX revealed the appropriate molar ratios exhibited by the constituent elements in the composites and FTIR gave some characteristic peaks which indicated the formation of CdS/ZnS nanocomposites. Electrochemical Impedance Spectroscopy was done to study charge transfer properties along the nanocomposites. Photocatalytic properties of the synthesized composites were monitored by the photocatalytic kinetic study of Acid Blue dye and p-chlorophenol under visible light irradiation. Results revealed the formation of stable core–shell nanocomposites and their efficient photocatalytic properties.