Determination of Content of Eight Elements in Metal Coating Smeared on Waste Plastics by X-ray Fluorescence Spectrometry

X-ray fluorescence spectrometry was used to detect the content of eight elements in metal coating smeared on waste plastics,and effects of sample cups,elements in plastic substrate,and interaction of elements in metal coating on detection results were analyzed. The results show that the RSD of the method used to detect element content in the metal coating smeared on the waste plastics ranged from 0.008% to 0.044%; the determination range of the eight elements was 0.002%-52.0%,and their detection limit ranged from 0.0002% to 0.0008%. The determination results of X-ray fluorescence spectrometry were consistent with that of ICP-AES. The method can provide technical support for the determination of damage and pollution caused by metal coating smeared on waste plastics.

Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence Spectrometry

A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy(LIBS),as a fast on-line analysis technology,has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants,the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present.In this paper,we propose a novel x-ray fluorescence(XRF) assisted LIBS method for high repeatability analysis of coal quality,which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal,but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements.With the combination of elemental lines in LIBS and XRF spectra,the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal.Quantitative analysis results show that the relative standard deviation(RSD) of C is 0.15%,the RSDs of other elements are less than 4%,and the standard deviations of calorific value,ash content,sulfur content and volatile matter are 0.11 MJ kg,0.17%,0.79% and 0.41%respectively,indicating that the method has good repeatability in determination of coal quality.This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

Possible Relevance of the Allende Meteorite Conditions in Prebiotic Chemistry: An Insight into the Chondrules and Organic Compounds

The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the magnetic minerals present in ordinary and carbonaceous chondrites, providing information on the evolution of magnetic fields. The interaction of organic compounds with magnetic minerals is a possible source of chemical diversity, which is crucial for molecular evolution. Carbon compounds in meteorites are of great scientific interest for a variety of reasons, such as their relevance to the origins of chirality in living organisms. This study presents the characterization of organic and mineral compounds in the Allende meteorite. The structural and physicochemical characterization of the Allende meteorite was accomplished through light microscopy, powder X-ray diffraction with complementary Rietveld refinement, Raman and infrared spectroscopy, mass spectrometry, scanning electron microscopy, and atomic force microscopy using magnetic signal methods to determine the complex structure and the interaction of organic compounds with magnetic Ni-Fe minerals. The presence of Liesegang-like patterns of chondrules in fragments of the Allende structure may also be relevant to understanding how the meteorite was formed. Other observations include the presence of magnetic materials and nanorod-like solids with relatively similar sizes as well as the heterogeneous distribution of carbon in chondrules. Signals observed in the Raman and infrared spectra resemble organic compounds such as carbon nanotubes and peptide-like molecules that have been previously reported in other meteorites, making the Mexican Allende meteorite a feasible sample for the study of the early Earth and exoplanetary bodies.

基于原子荧光光谱法的水环境汞含量检测技术研究

本文通过对相关文献进行查阅,对原子荧光光谱法的概念及其基本原理进行了研究,结合相关现代理论知识,采用原子荧光光谱法,对水环境中的汞含量进行了检测,并通过实验论证确定了该方法的有效性。希望能够为水环境汞含量检测质量的提升提供一定理论支持。

X射线荧光光谱在文件/纸质文物检验中的应用研究进展

X射线荧光光谱技术(X-ray fl uorescence, XRF)是一种实验室常见的元素分析方法,这种方法可分析样品中多种元素的种类和含量。XRF在法庭科学领域有广泛应用,本文从纸张、书写/印刷墨迹、纸币、纸质文物检验等方面综述XRF在文件检验中的应用,概述了基于XRF数据的文件真伪鉴别、串并、溯源和断代技术,介绍了元素定量分析过程中引入的数学统计方法,以及多种颜料的定性分析方法。最后,对XRF技术的应用进行了展望,讨论了该分析方法需要进一步研究的问题和未来发展趋势。

Review of the diagnosis of gastrointestinal lanthanum deposition

Lanthanum carbonate is used for treatment of hyperphosphatemia mostly in patients with chronic renal failure.Although lanthanum carbonate is safe,recently,lanthanum deposition in the gastrointestinal mucosa of patients has been reported in the literature.This review provides an overview of gastroduodenal lanthanum deposition and focuses on disease's endoscopic,radiological,and histological features,prevalence,and outcome,by reviewing relevant clinical studies,case reports,and basic research findings,to better understand the endoscopic manifestation of gastrointestinal lanthanum deposition.The possible relationship between gastric lanthanum deposition pattern and gastric mucosal atrophy is also illustrated;in patients without gastric mucosal atrophy,gastric lanthanum deposition appears as diffuse white lesions in the posterior wall and lesser curvature of the gastric body.In the gastric mucosa with atrophy,lanthanum-related lesions likely appear as annular or granular whitish lesions.Moreover,these white lesions are probably more frequently observed in the lower part of the stomach,where intestinal metaplasia begins.

Nano-tribological characteristics of lanthanum-based thin films on sulfonated self-assembled monolayer of 3-mercaptopropyl trimethoxysilane

Silane coupling reagent （3-mercaptopropyl trimethoxysilane （MPTS）） was prepared on silicon substrate to form two-dimensional Self-Assembled Monolayer （SAM） and the terminal -SH group in the film was in situ oxidized to -SO3H group to endow the film with good chemisorption ability. Thus, lanthanum-based thin films were deposited on oxidized MPTS-SAM to form rare earth composite thin films （RE thin films）, making use of the chemisorption ability of the -SO3H group. Atomic Force Microscope （AFM）, X-ray Photoelectron Spectrometry （XPS）, and contact angle measurements were used to characterize the RE thin films. Adhesive force and friction force of the RE thin films and silicon substrate were measured under various applied normal loads and scanning speed of AFM tip. The results showed that the friction force increased with applied normal loads and scanning speed of AFM tip. To study the effect of capillary force, tests were performed in various relative humidities. The results showed that the adhesive force of silicon substrate increased with relative humidity and the adhesive force of RE thin films only increased slightly with relative humidity. Research showed that surfaces with higher hydrophobic property reveal lowered adhesive and friction forces.

Growth of Fluorocarbon Films by Low-Pressure Dielectric Barrier Discharge

Plasma polymerized fluorocarbon （FC） films have been deposited on silicon substrates from dielectric barrier discharge （DBD） plasma of C4Fs at room temperature under a pressure of 25～125 Pa. The effects of the discharge pressure and frequency of power supply on the films have been systematically investigated. FC films with a less cross linked structure may be formed at a relatively high pressure. Increase in the frequency of power supply leads to a significant increase in the deposition rate. Static contact angle measurements show that deposited FC films have a stable, hydrophobic surface property. All deposited films show smooth surfaces with an atomic surface roughness. The relationship between plasma parameters and the properties of the deposited FC films are discussed.

Using X-ray computed tomography and micro-Raman spectrometry to measure individual particle surface area, volume, and morphology towards investigating atmospheric heterogeneous reactions

Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogeneous reactions usually have large variations and may not be relevant to real atmospheric conditions. One of the major reasons for this is the use of bulk samples in laboratory experiments, while particles in the atmosphere are suspended individually. A number of technologies have been developed recently to study heterogeneous reactions on the surfaces of individual particles. Precise measurements on the reactive surface area, volume, and morphology of individual particles are necessary for calculating the uptake coefficient, quantifying reactants and products, and understanding the reaction mechanism better. In this study, for the first time we used synchrotron radiation X-ray computed tomography（XCT） and micro-Raman spectrometry to measure individual CaCO_3 particle morphology, with sizes ranging from 3.5–6.5 μm. Particle surface area and volume were calculated using a reconstruction method based on software threedimensional（3-D） rendering. The XCT was first validated with high-resolution fieldemission scanning electron microscopy（FE-SEM） to acquire accurate CaCO_3 particle surface area and volume estimates. Our results showed an average difference of only 6.1% in surface area and 3.2% in volume measured either by micro-Raman spectrometry or X-ray tomography. X-ray tomography and FE-SEM can provide more morphological details of individual Ca CO3 particles than micro-Raman spectrometry. This study demonstrated that X-ray computed tomography and micro-Raman spectrometry can precisely measure the surface area, volume, and morphology of an individual particle.

Dealloying-induced dual-scale nanoporous indium-antimony anode for sodium/potassium ion batteries

InSb alloy is a promising candidate for sodium/potassium ion batteries(SIBs/PIBs)but challenged with achieving high performance by dramatic volumetric changes.Herein,nanoporous(np)-InSb with dualscale phases(cubic/hexagonal(C/H)-InSb)was fabricated by chemical dealloying of ternary Mg-In-Sb precursor.Operando X-ray diffraction(XRD)and ex-situ characterizations well rationalize the dealloying/alloying mechanisms and the formation of dual-scale microstructures/phases.As an anode for SIB/PIBs,the np-InSb electrode exhibits superior reversible capacities and lifespan compared with the monometallic porous(p)-In electrode,stemming from the dealloying-induced dual-scale nanoporous architecture and alloying strategy with proper composition.The operando XRD results demonstrate that the(de)sodiated mechanism of the np-InSb electrode involves a two-step(de)alloying process,while the(de)potassiated mechanism is associated with a full electrochemically-driven amorphization upon cycling.Additionally,the gas evolution during the(dis)charge process was monitored by on-line mass spectrometry.

Chemical Characterization of Auriferous Ores from the Brazilian State of Paraiba

One of the most important problems facing the gold industry is that the placer and free milling gold ores are almost terminating. Hence, the use of refractory ores has been increased during the recent years. In general, gold refractory ores occurs in various types of deposits associated with a range of minerals. Among the refractory ores, the sulfide type is the most common. The methodology employed in the mining process depends on the mode of occurrence of the ore and on the particle size, shape and degree of purity of the auriferous species. We have undertaken a mineralogical investigation of a representative sample of a complex gold mining ore collected in the municipality of Princesa Isabel, Paraiba, Brazil, using X-ray fluorescence spectrometry, X-ray diffractometry, infrared spectroscopy, inductively coupled plasma-atomic emission spectrometry and the Fire Assay. The results showed that the arsenic content of the ore was closely related to the gold content, and that the occurrence of “invisible gold” was associated primarily with pyrite and secondarily with arsenopyrite. The sulfur content of the ore was directly related to its refractoriness. It is concluded that gold mineralization in the study area is mainly of the gold-quartz-sulfide veins (lode gold), while the gold found in the mini-fractures of the deposits is probably associated with the hydrothermal processes that occurred in the region.

Geochemical Characterization and Mineralogy of Babouri-Figuil Oil Shale,North-Cameroon

Organic geochemistry methods such as high temperature combustion, Rock-Eval pyrolysis and gas analysis were used to analyze oil shale from Babouri-Figuil Basin. Results show that the average content of organic matter is 36.25 %wt, while that of mineral matter is 63.75 %wt. The total organic carbon (TOC) is between 15.93 %wt and 26.82 %wt. The HI vs. Tmax diagram indicates an immature Type I kerogen. The average value of the oil potential (S2b) is 149.95 mg HC/g rock. The gases obtained by retort process are H2, CO2, CO and CnH2n, CnH2n+2. Finally, it emerges that, the organic matter of Babouri-Figuil shales was immature or has just reached the beginning of the oil window. The mineralogical study of Babouri-Figuil oil shale has been carried out by means of XRD (X-Ray Diffractometry) and XRF (X-Ray Fluorescence spectrometry). The results show that mineral matrix contains silica, carbonates, sulphates, oxides and clay minerals. Besides, compounds contain metals and metalloids like Fe, In, Ca. The main oxides are SiO2 (majority), CaO, Fe2O3, Al2O3, SO3, and K2O.

Modulus and Hardness Change of Silicon and Sapphire Substrates by TiC/VC Multilayer Coatings

The nanohardness H of multilayer specimens TiC/VC@Si and TiC/VC@Sapphire prepared by Pulsed-Laser-Deposition is investigated to check the existence of a superlattice effect as known from TiN/VN multilayers. In the present work the multilayer period thickness λ varies between 1.34 nm and 24.8 nm (total layer thickness t ≈ 200 nm). Unlike Young’s modulus E, H is enhanced, regardless of t, by covering Si as well as sapphire with a TiC/VC multilayer;the relative load carrying capacity being larger for Si. The maximum value of H obtained is 38 GPa for TiC/VC@Sapphire. It is observed for a multilayer thickness of λ ≈ 10 nm. Hardness of TiC/VC@Sapphire obeys, after annealing, a Hall-Petch relation H = 35.25 + 6.945 λ–0.5 (H in GPa und λ≥ 10 nm). From orientation dependent X-ray absorption fine structure and X-ray reflection records, short-range order and layer geometry are derived. These analyses reveal a continuous approach of interatomic distances Ti-C and V-C for deceasing multilayer periods. High-resolution transmission electron microscopy shows that multilayers are nanostructured, i.e., not only TiC/VC phase boundaries but also subgrains represent obstacles against plastic deformation. Dislocations play a major role as sources of internal stress and vehicles of plasticity.

Study on activated carbon in chromium-containingwastewater treatment by XPS

The mechanism of activated carbon treatment with chromium-containing wastewater byX-ray photoelectron spectroscopy (XPS) and that of adsorption and reduction reaction of the acti-vated carbon with hexavalent chromium solution are presented in this paper. The XPS results showthat at PH<1,the activated carbon does not adsorb any chromium ion,and the main reaction is re-duction process of Cr(VI), at 1<pH<6, both reduction process of Cr(VI) and adsorption process ofCr(VI) and Cr(III) occur on the carbon surface, at PH >6,the main process is adsorption of the car-bon to Cr(VI). The optimum range of treatment is at pH 3-6,in which removal efficiency ofadsorption and reduction is relatively high. It demonstrates that the reduction mechanism is aheterogeneous acid catalysis process.

A Newly Developed Non-Destructive Tritium Measurement Technique and Its Application to V-4Cr-4Ti Alloy

A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry （BIXS）, has been developed recently. In the present study a V-4Cr-4Ti alloy was pre-heated at 1000℃ for 2 h to form a recrystallization structure before the tritium absorption experiments were conducted. Firstly the hydrogen isotope gas was charazterized by means of a quadrupole mass spectrometer （QMS） and a small-sized ionization chamber. Then hydrogen isotope absorption tests of V-4Cr-4Ti alloy were performed at 400 ℃ and the atomic concentration of hydrogen isotope in V-4Cr-4Ti alloy was estimated as 0.17% with a tritium content of approximately 2.5 ppm. Experimental results indicate that BIXS is a quite useful tool for quantitatively measuring the tritium content and tritium distribution in the surface layers of vanadium alloys and no strong trapping effects of tritium exist in the pre-heated V-4Cr-4Ti alloy.

Measurement of niobium reaction rate for material surveillance tests in fast reactors

A highly accurate and precise technique for measurement of the 93 Nb(n,n’)93m Nb reaction rate was established for the material surveillance tests,etc.in fast reactors.The self-absorption effect on the measurement of the characteristic X-rays emitted by 93m Nb was decreased by the dissolution and evaporation to dryness of niobium dosimeter.A highly precise count of the number of 93 Nb atoms was obtained by measuring the niobium solution concentration using inductively coupled plasma mass spectrometry.X-rays of 93m Nb were measured accurately by means of comparing the X-ray intensity of irradiated niobium solution with that of the solution in which stable 93 Nb was added.The difference between both intensities indicates the effect of 182 Ta,which is generated from an impurity tantalum,and the intensity of X-rays from 93m Nb was evaluated.Measurement error of the 93 Nb(n,n’)93m Nb reaction rate was reduced to be less than 4%,which was equivalent to the other reaction rate errors of dosimeters used for Joyo dosimetry.In addition,an advanced technique using Resonance Ionization Mass Spectrometry was proposed for the precise measurement of 93m Nb yield,and 93m Nb will be resonance-ionized selectively by discriminating the hyperfine splitting of the atomic energy levels between 93 Nb and 93m Nb at high resolution.

Neutron Activation Analysis and Scanning Electron Microscopy of Phytoplankton in the Coastal Zone of Crimea (The Black Sea)

The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplankton is important for interpretation of physiological and functional states of coastal ecosystems. The present study is focused on the structure and elemental composition of the phytoplankton assemblages from the different coastal zones by instrumental neutron activation analysis (INAA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). For the first time these complementary techniques were simultaneously applied to study the Black Sea phytoplankton. The concentrations of 45 elements in the coastal phytoplankton communities used as bioindicator of inorganic contamination of the Black Sea coastal area near Sevastopol, Ukraine, were determined. Phytoplankton samples were collected by total tows of the plankton net with 35 μm pore size at 3 stations situated in polluted and relatively pristine water areas of the Sevastopol coastal zone during autumn period of the phytoplankton growth. The concentration of Mg, Al, Sc, Ti, V, Mn, As, Rb, Ba, Th and Fe, Cr increases exponentially from relatively pristine station to more polluted station and 10-times and 3-times greater, respectively, in the phytoplankton of the Sevastopol Bay. The rare-earth elements have relatively the same concentration values less than 1 μg/g and tend to accumulate in the phytoplankton from the polluted station in the Sevastopol Bay. The obtained results are in a good agreement with the elemental concentration data in the oceanic plankton, plankton communities from the White Sea and the Black Sea. Using energy-dispersive X-ray spectrometry the mineral particles of unknown origin and impurities of copper (0.42% by weight) in the phytoplankton at the polluted station and zinc (0.57% by weight) at the relatively pristine station were determined.

Application of electron microscopy in gastroenterology

Electron microscopy has long been used in research in the fields of life sciences and materials sciences.Transmission and scanning electron microscopy and energy-dispersive X-ray spectroscopy(EDX)analyses have also been performed in the field of gastroenterology.Electron microscopy and EDX enable(1)Observation of ultrastructural differences in esophageal epithelial cells in patients with gastroesophageal reflux and eosinophilic esophagitis;(2)Detection of lanthanum deposition in the stomach and duodenum;(3)Ultrastructural and elemental analyses of enteroliths and bezoars;(4)Detection and characterization of microorganisms in the gastrointestinal tract;(5)Diagnosis of gastrointestinal tumors with neuroendocrine differentiation;and(6)Analysis of gold nanoparticles potentially used in endoscopic photodynamic therapy.This review aims to foster a better understanding of electron microscopy applications by reviewing relevant clinical studies,basic research findings,and the state of current research carried out in gastroenterology science.

原子荧光光谱法测定尿锑浓度

[目的]建立原子荧光光谱法测定尿锑浓度的检测方法。[方法]尿样经混合酸消化后,加入硫脲和抗坏血酸使5价锑还原为3价锑,再加入硼氢化钾还原生成锑化氢,由氩气载入石英原子化器中分解为原子态锑,在锑空心阴极灯发射光的激发下产生原子荧光,荧光强度与标准系列比较定量。[结果]尿锑浓度为0.0-10.0μg/L的线性关系较好,相关系数为0.999 4-0.999 9;最低检出限为0.06μg/L;相对标准偏差为1.9%-2.4%;平均加标回收率为99.7%。[结论]建立的湿法消解-氢化物发生-原子荧光光谱法测定尿锑实用、快速、准确、灵敏度高、基体干扰少,便于推广运用,尤其适用于大批量人群职业健康体检尿锑的检测。