Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens

To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.

Comparison of Antioxidant Activities of Silver Nanoparticles and Methanol Extracts of Three Indigenous Nigeria Herbal Seeds

The antioxidant of seeds was carried out using extracts from methanol and Silver Nanoparticles from the spice. The SEM shows the shapes, dispersion and agglomeration of the sample, while the EDX confirms the SEM and the presence of some compounds. The FT-IR reveals the AgNPs capping and reducing the particular biomolecule from the functional group for identification. Compounds found in the FT-IR seeds of Capsicum annum are Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol). Monodora myristica are Mo L (Molybdenum), Ag L (Silver iodide), C K (Cyanogen chloride), P K (Phenol), Mg K (Magnesium). Piper guineense are Ag L (Silver iodide), Ci K (Potassium chloride), C K (Cyanogen chloride), P K (Phenol). The seeds show that the AgNPS of CA and MM has a better antioxidant activity than the methanol of CA and MM, while the PG methanol has a better activity than the AgNPS PG. The control (Catechin and Galic acid) has a slight overall better DPPH activity than the AgNPS. It is important to note that there is a concentration dependency in CA, MM AgNPS, PG methanol respectively. Notably, at CA methanol, the conc. at 125 was higher than the conc. at 250. Hence, there is need to create a great part in using plant samples for making tabulated or capsulated drugs for treatment of diseases and using plant silver nanoparticles to develop a healthy food/drug preservative package material “smart packaging” that will enhance shelf-life.

Mossbauer,X-Ray and Magnetic Studies of Black Sand from the Italian Mediterranean Sea

The study of natural magnetic sands is instrumental to investigate the geological aspects of their formation and of the origin of their territory. In particular, Mossbauer spectroscopy provides unique information on their iron content and on the oxidation state of iron in their mineral composition. The Italian coast on the Mediterranean Sea near Rome is known for the presence of highly magnetic black sands of volcanic origin. A study of the room temperature Mossbauer spectrum, powder X-ray diffraction, energy dispersive X-ray spectroscopy, and magnetic measurements of a sample of black magnetic sand collected on the seashore of the town of Ladispoli is performed. This study reveals magnetite as main constituent with iron in both tetrahedral and octahedral sites. Minor constituents are the iron minerals hematite and ilmenite, the iron containing minerals diopsite, gossular, and allanite, as well as ubiquitous sanidine, quartz, and calcite.

Mechanism of cement-stabilized soil polluted by magnesium sulfate

In order to simulate and study the mechanism of cement stabilized soils polluted by different contents of magnesium sulfate(MS), a series of tests were conducted on the cemented soil samples, including unconfined compression strength(UCS) tests of blocks, X-ray diffraction(XRD) phase analysis of powder samples, microstructure by scanning electronic microscopy(SEM),element composition by energy dispersive spectrometry(EDS), and pore distribution analysis by Image Processed Plus 6.0(IPP 6.0)software. The UCS test results show that UCS of cemented soils reaches the peak value when the MS content is 4.5 g/kg. While, the UCS for Sample MS4 having the MS content of 18.0 g/kg is the lowest among all tested samples. Based on the EDS analysis results,Sample MS4 has the greater contents for the three elements, oxygen(O), magnesium(Mg) and sulfur(S), than Sample MS1. From the XRD phase analysis, C-A-S-H(3Ca O·Al2O3·3Ca SO4·32H2O and 3Ca O·Al2O3·Ca SO4·18H2O), M-A-H(Mg O·Al2O3·H2O), M-S-H(Mg O·Si O2·H2O), Mg(OH)2 and Ca SO4 phase diffraction peaks are obviously intense due to the chemical action associated with the MS. The pore distribution analysis shows that the hydrated products change the distribution of cemented soil pores and the pores with average diameter(AD) of 2-50 μm play a key role in terms of the whole structure of cemented soil. The microscopic structure of the cemented soil with MS exhibits the intertwined and embedded characteristics between the cement and granular soils from the SEM images of cemented soils. The microstructure analysis shows that the magnesium sulfate acts as the additive, which is beneficial to the soil strength when the MS content is low(i.e., Sample MS2). However, higher MS amount involving a chemical action makes samples crystallize and expand, which is adverse to the UCS of cemented soils(i.e., Sample MS4).

生物质垃圾与煤混烧污染特征的研究

对不同配比复合垃圾衍生燃料做实验试烧,并对燃烧产生的NOx、SO2等燃烧排放污染物进行了监测.利用扫描电镜(SEM)和能谱(EDX)结合联用技术观察了生物质垃圾与煤混合压制燃料的燃烧颗粒的微观形态特征.结果表明,随着生物质比例的加大,发现飞灰颗粒有细化的现象.Cl元素的排放主要出现在燃烧初期.钾的主要存在形式是氯化钾.飞灰颗粒的所有能谱分析中并没有检测到重金属元素的存在.

扫描电子显微镜及能谱分析技术在黄土微结构研究上的应用

我国利用扫描电子显微镜研究黄土微结构的报道始于20世纪的70年代。随着当代电子技术和计算机的发展,利用扫描电子显微镜和能谱分析技术,可以在观测微结构的同时,实现对微结构元素分析的目的。本研究介绍了扫描电子显微镜和能谱分析技术的原理,并从样品制作、处理、观察和结果分析等角度就二者在黄土微结构研究上的应用做了探讨。

纳米碳纤维化学镀镍-铁-钴-磷合金镀层

在铁片试样上研究了化学镀Ni-Fe-Co-P合金镀层的工艺,利用此工艺在经过敏化、活化处理后的纳米碳纤维表面沉积出Ni-Fe-Co-P合金镀层。采用能量色散X射线谱(EDS)分析得出镀层成分,利用扫描电子显微镜(SEM)观察镀层形貌。结果表明,镀层的沉积速率随镀液中氯化镍质量浓度的增加而增加,随硫酸钴质量浓度的增加而降低;通过控制镀液中c(Co2+)/c(Ni2+)的比值,可控制沉积速率及镀层中镍、钴元素的相对含量;镀后的纳米碳纤维分散性好,获得了连续、均匀的Ni-Fe-Co-P合金镀层。

PVC/PP共混体系的X射线能谱微区分析

用Ｘ射线能谱微区分析方法对ＰＶＣ／ＰＰ共混物进行了研究，得到了共混物断面氯元素的面分布图，并对面分布图像进行了相分析，从亚微观层次揭示了ＰＶＣ／ ＰＰ共混物的相结构．将面分布图像与扫描电镜（ＳＥＭ） 对ＰＶＣ／ＰＰ共混物的形态照片进行了比较．结果表明，元素面分布图像比形态照片具有更清晰、直观的特点，能准确说明聚合物的相结构。

能谱仪半定量分析用的元素Kx·s因子的实验测定和理论校正

本文利用无机盐溶液微滴结晶为标样,在装备有英国Link公司AN10000能谱仪的JEM—1200EX分析电镜上,测定了一组半定量分析用的相对S元素的K_(x·s)因子,并通过计算微滴结晶厚度和吸收校正因子,从理论上进行了校正。同时,对利用K因子测定的已知元素浓度比的实验值与其实际值进行了比较。结果表明,这些K因子的实验值是准确的。

Impact of open dumping of municipal solid waste on soil properties in mountainous region

This paper presents the effect of open dumping of municipal solid waste(MSW) on soil characteristics in the mountainous region of Himachal Pradesh, India. The solid waste of dumpsite contains various complex characteristics with organic fractions of the highest proportions. As leachate percolates into the soil, it migrates contaminants into the soil and affects soil stability and strength. The study includes the geotechnical investigation of dump soil characteristics and its comparison with the natural soil samples taken from outside the proximity of dumpsites. The geochemical analysis of dumpsite soil samples was also carried out by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).Visual inspection revealed that the MSW consists of high fraction of organics, followed by paper. The soil samples were collected from five trial pits in the dumpsites at depths of 0.5 m, 1 m and 1.5 m. Then the collected soil samples were subjected to specific gravity test, grain size analysis, Atterberg’s limit test,compaction test, direct shear test, California bearing ratio(CBR) test and permeability analysis. The study indicated that the dumpsite soils from four study regions show decreasing trends in the values of maximum dry density(MDD), specific gravity, cohesion and CBR, and increasing permeability as compared to the natural soil. The results show that the geotechnical properties of the soils at all four study locations have been severely hampered due to contamination induced by open dumping of waste.

Palaeodiet of Miocene Producers and Depositional Environments:Inferences from the First Evidence of Microcoprolites from India

This paper reviews research on coprolites from India,providing the first evidence of microcoprolites from the early Miocene(Aquitanian)Khari Nadi Formation sedimentary succession,exposed about 1.5 km northeast of the village of Kotada,Kachchh(Kutch)District,Gujarat State,western India.Morphometric and size comparisons(in a statistical framework)with known coprolites from the Mesozoic-Cenozoic successions of India(including those recorded herein)and globally suggest that fishes were the likely producers of the Kotada coprolites.Scanning electron microscopy confirms the presence of fish dental remains within the coprolites,while both Scanning Electron Microscopy(SEM)and Energy Dispersive X-ray Spectroscopy(EDS)reveal the phosphatic nature of the microscopic coprolite specimens(recorded herein)hinting that the producer(s)were predominantly carnivorous(ichthyophagous)in their diet.Furthermore,X-Ray Fluorescence(XRF)analysis of the host and associated lithologies allows us to deduce that the Kotada coprolites were deposited in a shallow marine environment,with possible aerial exposure of the host lithology occurring at some point after deposition.To the best of our knowledge,the present report is the first record of microscopic fish coprolites from India,as well as being the first from the Aquitanian of India and the oldest Neogene record from India.

Calculation of the coefficient and dynamics of water diffusion in graphite joints

The coefficient and dynamics of water diffusion in adhesive-graphite joints were calculated in-situ with energy dispersive X-ray (EDX) analysis, a method that is significantly simpler than elemental analysis. Water diffusion coefficient and dynamics of adhesive-graphite joints treated by different surface treatment methods were also investigated. Calculation results indicated that the water diffusion rate in adhesive-graphite joints treated by sandpaper was higher than that treated by chemical oxidation or by silane couple agent. Also the durability of graphite joints treated by coupling agent is superior to that treated by chemical oxidation or sandpaper burnishing.

Influence of silicon on microdistribution of mineral ions in roots of salt-stressed barley as associated with salt tolerance in plants

Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown hydroponically to investigate the microdistribution of mineral ions in roots as affected by silicon (Si) with respect to salt tolerance. The experiment was undertaken consisting of two treatments with 3 replicates: (i) 120 mmol·L-1 NaCI alone (referred to as Si-NaCI+), (ii) 120 mmol·L-1 NaCI + 1.0 mmol·L-1 Si (as potassium silicate) (referred to as Si+NaCI+). Plant root tips were harvested for microanalysis using an energy dispersive X-ray microanalyzer (EDX) 30 d after transplanting. Higher Cl and Na X-ray peaks were recorded in the root epidermal, cortical and stelar cells of roots for the treatment Si-NaCI+ with the majorities of Na and Cl being accumulated in epidermal and cortical cells, while relatively low K peaks were observed regardless of the barley cultivars used. By contrast, considerably higher K peaks were detected in the epidermal, cortical and stelar cells of the roots for the treatment Si+NaCI+, but lower Cl and Na peaks were also observed for this treatment with both Na and Cl ions being evenly distributed in the epidermal, cortical and stelar cells. These findings directly support our previous finding, which showed that Si depressed the uptake of sodium but enhanced the uptake of potassium by salt-stressed barley. We believe that one of the possible mechanisms involved in Si-enhancement of salt tolerance in barley is attributed to the Si-induced changes in the uptake and microdistribution of mineral ions in plants.

Influence of ash composition on the sintering behavior during pressurized combustion and gasification process

To determine the ash characteristics during fluidized bed combustion and gasification purposes, the investigation of the impacts of chemical composition of Jincheng coal ash on the sintering temperature was conducted. A series of experiments on the sintering behavior at 0.5 MPa was performed using the pressurized pressure-drop technique in the combustion and gasification atmospheres. Meanwhile, the mineral transformations of sintered ash pellets were observed using X-ray diffractometer （XRD） analyzer to better understand the experimental results. In addition, quantitative XRD and field emission scanning electron microscope/energy dispersive X-ray spectrometer （FE-SEM/EDS） analyses of ash samples were used for clarifying the detailed ash melting mechanism. These results show that the addition of Fe203 can obviously reduce the sintering temperatures under gasification atmospheres, and only affect a little the sintering temperature under combustion atmosphere. This may be due to the presence of iron-bearing minerals, which will react with other ash compositions to produce low-melting-point eutectics. The FE-SEM/EDS analyses of ash samples with Fe203 additive show consistent results with the XRD measurements. The CaO and Na20 can reduce the sintering temperatures under both the combustion and gasification atmospheres. This can be also contributed to the formation of low-melting-point eutectics, decreasing the sintering temperature. Moreover, the fluxing minerals, such as magnetite, anhydrite, muscovite, albite and nepheline, contribute mostly to the reduction of the sintering temperature while the feldspar minerals, such as anorthite, gehlenite and sanidine, can react with other minerals to produce low-melting-point eutectics, and thereby reduce the sintering temperatures.

Advanced TEM Characterization for Single-atom Catalysts:from Ex-situ Towards In-situ

Clean energy innovation has triggered the development of single-atom catalysts(SACs)due to their excellent catalytic activity,high tunability and low cost.The success of SACs for many catalytic reactions has opened a new field,where the fundamentals of catalytic property-structure relationship at atomic level await exploration,and thus raises challenges for structural characterization.Among the characterization techniques for SACs,aberration-corrected transmission electron microscopy(TEM)has become an essential tool for direct visualization of single atoms.In this review,we briefly summarize recent studies on SACs using advanced TEM.We first introduce TEM methods,which are particularly important for SACs characterization,and then discuss the applications of advanced TEM for SAC characterization,where not only atomic dispersion of single atoms can be studied,but also the distribution of elements and the valence state with local coordination can be resolved.We further extend our review towards in-situ TEM,which has increasing importance for the fundamental understanding of catalytic mechanism.Perspectives of TEM for SACs are finally discussed.

Understanding the galvanic corrosion of the Q-phase/Al couple using SVET and SIET

The galvanic corrosion of the Q-phase/Al couple in 0.1 M NaCl solutions has been studied using the scanning vibrating electrode technique (SVET)f the scanning ion-selective electrode technique (SIET) and energy dispersive X-ray spectroscopy (EDX). The galvanic corrosion of the Q-phase/Al couple was found to be dependent on pH and immersion time. Current density maps obtained by SVET shows that the anodic oxidation processes emerge from Al in a localized manner in pH 2 and 6 solutions but is initiated in a uniform manner in pH 13 solution, whereas, the cathodic processes are more homogeneously distributed over the Q-phase at pH 2.6 and 13. It is seen that the Q-phase remains cathodic in the Q-phase/Al couple in acidic, neutral and alkaline solutions indicating that the galvanic polarity of the Q-phase is independent of pH. The effect of the galvanic corrosion was largest at pH 2 and 13 compared to pH 6. The pH map obtained by SIET indicates that the galvanic activity of the Q-phase/Al couple proceeds via heavy alkalization of the Q-phase surface with the generation of appreciable amounts of OH~ ions. The enrichment of Cu indicated by EDX is responsible for the observed cathodic activity of the Q-phase in the Q-phase/Al couple.