Kaolinite flocculation induced by smectite addition - a transmission X-ray microscopic study.

PubMed

Zbik, Marek S; Song, Yen-Fang; Frost, Ray L

2010-09-01

The influence of smectite addition on kaolinite suspensions in water was investigated by transmission X-ray microscopy (TXM) and Scanning Electron Microscopy (SEM). Sedimentation test screening was also conducted. Micrographs were processed by the STatistic IMage Analysing (STIMAN) program and structural parameters were calculated. From the results of the sedimentation tests important influences of small smectite additions to about 3wt.% on kaolinite suspension flocculation has been found. In order to determine the reason for this smectite impact on kaolinite suspension, macroscopic behaviour micro-structural examination using Transmission X-ray Microscope (TXM) and SEM has been undertaken. TXM & SEM micrographs of freeze-dried kaolinite-smectite suspensions with up to 20% smectite showed a high degree of orientation of the fabric made of highly oriented particles and greatest density when 3wt.% of smectite was added to the 10wt.% dense kaolinite suspension. In contrast, suspensions containing pure kaolinite do not show such platelet mutual orientation but homogenous network of randomly oriented kaolinite platelets. This suggests that in kaolinite-smectite suspensions, smectite forms highly oriented basic framework into which kaolinite platelets may bond in face to face preferential contacts strengthening structure and allowing them to show plastic behaviour which is cause of platelets orientation. Copyright 2010 Elsevier Inc. All rights reserved.

Simple route to (NH4)xWO3 nanorods for near infrared absorption

NASA Astrophysics Data System (ADS)

Guo, Chongshen; Yin, Shu; Dong, Qiang; Sato, Tsugio

2012-05-01

Described here is how to synthesize one-dimensional ammonium tungsten bronze ((NH4)xWO3) by a facile solvothermal approach in which ethylene glycol and acetic acid were employed as solvents and ammonium paratungstate was used as a starting material, as well as how to develop the near infrared absorption properties of (NH4)xWO3 nanorods for application as a solar light control filter. The as-obtained product was characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), atomic force microscope (AFM) and UV-Vis-NIR spectra. The SEM and TEM images clearly revealed that the obtained sample possessed rod/fiber-like morphologies with diameters around 120 nm. As determined by UV-Vis-NIR optical measurement, the thin film consisted of (NH4)xWO3 nanoparticles, which can selectively transmit most visible lights, but strongly absorb the near-infrared (NIR) lights and ultraviolet rays. These interesting optical properties make the (NH4)xWO3 nanorods suitable for the solar control windows.Described here is how to synthesize one-dimensional ammonium tungsten bronze ((NH4)xWO3) by a facile solvothermal approach in which ethylene glycol and acetic acid were employed as solvents and ammonium paratungstate was used as a starting material, as well as how to develop the near infrared absorption properties of (NH4)xWO3 nanorods for application as a solar light control filter. The as-obtained product was characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), atomic force microscope (AFM) and UV-Vis-NIR spectra. The SEM and TEM images clearly revealed that the obtained sample possessed rod/fiber-like morphologies with diameters around 120 nm. As determined by UV-Vis-NIR optical measurement, the thin film consisted of (NH4)xWO3 nanoparticles, which can selectively transmit most visible lights, but strongly absorb the near-infrared (NIR) lights and ultraviolet rays. These interesting optical properties make the (NH4)xWO3 nanorods suitable for the solar control windows. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30612c

Remediation of uranium-contaminated groundwater by sorption onto hydoxyapatite derived from catfish bones

USDA-ARS?s Scientific Manuscript database

Hydroxyapatite was prepared from catfish bones, called catfish hydroxyapatite (CFHA), by mechanical and chemical treatment methods and was characterized by x-ray diffraction (X-RD) and scanning electron microscope (SEM) techniques to confirm the presence of hydroxyapatite. The ability of CFHA to rem...

Nail Damage (Severe Onychodystrophy) Induced by Acrylate Glue: Scanning Electron Microscopy and Energy Dispersive X-Ray Investigations

PubMed Central

Pinteala, Tudor; Chiriac, Anca Eduard; Rosca, Irina; Larese Filon, Francesca; Pinteala, Mariana; Chiriac, Anca; Podoleanu, Cristian; Stolnicu, Simona; Coros, Marius Florin; Coroaba, Adina

2017-01-01

Background Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques have been used in various fields of medical research, including different pathologies of the nails; however, no studies have focused on obtaining high-resolution microscopic images and elemental analysis of disorders caused by synthetic nails and acrylic adhesives. Methods Damaged/injured fingernails caused by the use of acrylate glue and synthetic nails were investigated using SEM and EDX methods. Results SEM and EDX proved that synthetic nails, acrylic glue, and nails damaged by contact with acrylate glue have a different morphology and different composition compared to healthy human nails. Conclusions SEM and EDX analysis can give useful information about the aspects of topography (surface sample), morphology (shape and size), hardness or reflectivity, and the elemental composition of nails. PMID:28232921

Development of 1500mm Wide Wrought Magnesium Alloys by Twin Roll Casting Technique in Turkey

NASA Astrophysics Data System (ADS)

Duygulu, Ozgur; Ucuncuoglu, Selda; Oktay, Gizem; Temur, Deniz Sultan; Yucel, Onuralp; Kaya, Ali Arslan

Magnesium alloy AZ31, AZ61, AZ91, AM50 and AM60 sheets were produced by twin roll casting first time in Turkey. Sheets of 4.5-6.5mm thick and 1500mm width were successfully achieved. Microstructure of the sheet was analyzed by optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Semi-quantitative analyses were performed by SEM-EDS. In addition, X-ray studies were performed for both characterization and texture purposes. Mechanical properties were investigated by tensile tests and also hardness measurements. Homogenization and annealing heat treatments were performed on the produced sheets.

Comparing the detection of iron-based pottery pigment on a carbon-coated sherd by SEM-EDS and by Micro-XRF-SEM.

PubMed

Pendleton, Michael W; Washburn, Dorothy K; Ellis, E Ann; Pendleton, Bonnie B

2014-03-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis.

Comparing the Detection of Iron-Based Pottery Pigment on a Carbon-Coated Sherd by SEM-EDS and by Micro-XRF-SEM

PubMed Central

Pendleton, Michael W.; Washburn, Dorothy K.; Ellis, E. Ann; Pendleton, Bonnie B.

2014-01-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis. PMID:24600333

Three-dimensional mapping of soil chemical characteristics at micrometric scale: Statistical prediction by combining 2D SEM-EDX data and 3D X-ray computed micro-tomographic images

NASA Astrophysics Data System (ADS)

Hapca, Simona

2015-04-01

Many soil properties and functions emerge from interactions of physical, chemical and biological processes at microscopic scales, which can be understood only by integrating techniques that traditionally are developed within separate disciplines. While recent advances in imaging techniques, such as X-ray computed tomography (X-ray CT), offer the possibility to reconstruct the 3D physical structure at fine resolutions, for the distribution of chemicals in soil, existing methods, based on scanning electron microscope (SEM) and energy dispersive X-ray detection (EDX), allow for characterization of the chemical composition only on 2D surfaces. At present, direct 3D measurement techniques are still lacking, sequential sectioning of soils, followed by 2D mapping of chemical elements and interpolation to 3D, being an alternative which is explored in this study. Specifically, we develop an integrated experimental and theoretical framework which combines 3D X-ray CT imaging technique with 2D SEM-EDX and use spatial statistics methods to map the chemical composition of soil in 3D. The procedure involves three stages 1) scanning a resin impregnated soil cube by X-ray CT, followed by precision cutting to produce parallel thin slices, the surfaces of which are scanned by SEM-EDX, 2) alignment of the 2D chemical maps within the internal 3D structure of the soil cube, and 3) development, of spatial statistics methods to predict the chemical composition of 3D soil based on the observed 2D chemical and 3D physical data. Specifically, three statistical models consisting of a regression tree, a regression tree kriging and cokriging model were used to predict the 3D spatial distribution of carbon, silicon, iron and oxygen in soil, these chemical elements showing a good spatial agreement between the X-ray grayscale intensities and the corresponding 2D SEM-EDX data. Due to the spatial correlation between the physical and chemical data, the regression-tree model showed a great potential in predicting chemical composition in particular for iron, which is generally sparsely distributed in soil. For carbon, silicon and oxygen, which are more densely distributed, the additional kriging of the regression tree residuals improved significantly the prediction, whereas prediction based on co-kriging was less consistent across replicates, underperforming regression-tree kriging. The present study shows a great potential in integrating geo-statistical methods with imaging techniques to unveil the 3D chemical structure of soil at very fine scales, the framework being suitable to be further applied to other types of imaging data such as images of biological thin sections for characterization of microbial distribution. Key words: X-ray CT, SEM-EDX, segmentation techniques, spatial correlation, 3D soil images, 2D chemical maps.

Dynamic-scanning-electron-microscope study of friction and wear

NASA Technical Reports Server (NTRS)

Brainard, W. A.; Buckley, D. H.

1974-01-01

A friction and wear apparatus was built into a real time scanning electron microscope (SEM). The apparatus and SEM comprise a system which provides the capability of performing dynamic friction and wear experiments in situ. When the system is used in conjunction with dispersive X-ray analysis, a wide range of information on the wearing process can be obtained. The type of wear and variation with speed, load, and time can be investigated. The source, size, and distribution of wear particles can be determined and metallic transferal observed. Some typical results obtained with aluminum, copper, and iron specimens are given.

The application of scanning electron microscopy to fractography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, C.R.; McGill, B.L.

1994-10-01

Many failures involve fracture, and determination of the fracture process is a key factor in understanding the failure. This is frequently accomplished by characterizing the topography of the fracture surface. Scanning electron microscopy has a prominent role in fractography due to three features of the scanning electron microscope (SEM): high resolution, great depth of field, and the ability to obtain chemical information via analysis of the X-rays generated by the electrons. A qualitative treatment is presented of the interaction of electrons with a sample and the effect of the SEM operating parameters on image formation, quality, and X-ray analysis. Fractographsmore » are presented to illustrate these features of scanning electron microscopy and to illustrate the limitations and precautions in obtaining fractographs and x-ray analyses. The review is concluded with examples of fracture surface features of metallic, ceramic, and polymeric materials.« less

Crystal Structure, Magnetic and Optical Properties of Mn-Doped BiFeO₃ by Hydrothermal Synthesis.

PubMed

Zhang, Ning; Wei, Qinhua; Qin, Laishun; Chen, Da; Chen, Zhi; Niu, Feng; Wang, Jiangying; Huanag, Yuexiang

2017-01-01

In this paper, Mn doped BiFeO₃ were firstly synthesized by hydrothermal process. The influence of Mn doping on structural, optical and magnetic properties of BiFeO₃ was studied. The different amounts of Mn doping in BiFeO₃ were characterized by X-ray diffraction, Scanning Electron Microscope, Energy Dispersive X-ray Spectroscope, UV-Vis diffuse reflectance spectroscopy and magnetic measurements. The X-ray diffraction (XRD) patterns confirmed the formation of pure phase rhombohedral structure in BiFe(1−x) Mn (x) O₃ (x = 0.01, 0.03, 0.05, 0.07) samples. The morphologies and chemical compositions of as-prepared samples could be observed by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscope (EDS). A relative large saturated magnetization (Ms) of 0.53 emu/g for x = 0.07 sample was obtained at room temperature, which is considered to be Mn ions doping. UV-Vis diffuse reflectance spectroscopy showed strong absorption of light in the range of 200–1000 nm, indicating the optical band gap in the visible region for these samples. This implied that BiFe(1−x) Mn(x)O₃ may be a potential photocatalyst for utilizing solar energy.

Determination of the sequence of intersecting lines using Focused Ion Beam/Scanning Electron Microscope.

PubMed

Kim, Jiye; Kim, MinJung; An, JinWook; Kim, Yunje

2016-05-01

The aim of this study was to verify that the combination of focused ion beam (FIB) and scanning electron microscope/energy-dispersive X-ray (SEM/EDX) could be applied to determine the sequence of line crossings. The samples were transferred into FIB/SEM for FIB milling and an imaging operation. EDX was able to explore the chemical components and the corresponding elemental distribution in the intersection. The technique was successful in determining the sequence of heterogeneous line intersections produced using gel pens and red sealing ink with highest success rate (100% correctness). These observations show that the FIB/SEM was the appropriate instrument for an overall examination of document. © 2016 American Academy of Forensic Sciences.

Morphology-controllable of Sn doped ZnO nanorods prepared by spray pyrolysis for transparent electrode application

NASA Astrophysics Data System (ADS)

Hameed, M. Shahul; Princice, J. Joseph; Babu, N. Ramesh; Zahirullah, S. Syed; Deshmukh, Sampat G.; Arunachalam, A.

2018-05-01

Transparent conductive Sn doped ZnO nanorods have been deposited at various doping level by spray pyrolysis technique on glass substrate. The structural, surface morphological and optical properties of these films have been investigated with the help of X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and UV-Vis spectrophotometer respectively. XRD patterns revealed a successful high quality growth of single crystal ZnO nanorods with hexagonal wurtzite structure having (002) preferred orientation. The scanning electron microscope (SEM) image of the prepared films exposed the uniform distribution of Sn doped ZnO nanorod shaped grains. All these films were highly transparent in the visible region with average transmittance of 90%.

Scanning electron microscopy/energy dispersive spectrometry fixedbeam or overscan x-ray microanalysis of particles can miss the real structure: x-ray spectrum image mapping reveals the true nature

NASA Astrophysics Data System (ADS)

Newbury, Dale E.; Ritchie, Nicholas W. M.

2013-05-01

The typical strategy for analysis of a microscopic particle by scanning electron microscopy/energy dispersive spectrometry x-ray microanalysis (SEM/EDS) is to use a fixed beam placed at the particle center or to continuously overscan to gather an "averaged" x-ray spectrum. While useful, such strategies inevitably concede any possibility of recognizing microstructure within the particle, and such fine scale structure is often critical for understanding the origins, behavior, and fate of particles. Elemental imaging by x-ray mapping has been a mainstay of SEM/EDS analytical practice for many years, but the time penalty associated with mapping with older EDS technology has discouraged its general use and reserved it more for detailed studies that justified the time investment. The emergence of the high throughput, high peak stability silicon drift detector (SDD-EDS) has enabled a more effective particle mapping strategy: "flash" x-ray spectrum image maps can now be recorded in seconds that capture the spatial distribution of major (concentration, C > 0.1 mass fraction) and minor (0.01 <= C <= 0.1) constituents. New SEM/SDD-EDS instrument configurations feature multiple SDDs that view the specimen from widely spaced azimuthal angles. Multiple, simultaneous measurements from different angles enable x-ray spectrometry and mapping that can minimize the strong geometric effects of particles. The NIST DTSA-II software engine is a powerful aid for quantitatively analyzing EDS spectra measured individually as well as for mapping information (available free for Java platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

Development of SEM/STEM-WDX for highly sensitive detection of light elements

NASA Astrophysics Data System (ADS)

Anan, Y.; Koguchi, M.; Kimura, T.; Sekiguchi, T.

2018-02-01

In this study, to detect the light element lithium (Li) and to detect low dosed Boron (B) in the local area at nm order, we developed an analytical electron microscope equipped with an improved serial (S)-type WDX (wavelength dispersive X-ray spectroscopy) system. In detail, to detect Li, we developed a high-conductivity multi-capillary X-ray (MCX) lens, and a diffractor with a lattice spacing (d) of 15 nm, and with a spacing variation (δ d) of 0.8 nm. Moreover, to detect low dosed light element B, we designed a high-conductivity MCX lens based on the soft X-ray reflectivity in the capillary and calculation. We developed a large-solid-angle MCX lens whose conductivity of the characteristic X-rays of B became 20 times higher than that of an MCX lens with a 30-mm focal length. Our developed analytical electron microscope was applied to a LiAl specimen and a low B-doped Si substrate specimen, and the performance of this analytical electron microscope was evaluated. As a results, this analytical electron microscope could detect the characteristic X-rays of Li with a minimum mass fraction (MMF) of 8.4 atomic % (at. %). The energy resolution was 1 eV at 55 eV. From the results of measuring the line profile of B for the unpatterned B-implantation area on a B-doped Si substrate specimen, the measured line profile data were in good agreement with secondary ion mass spectrometry data up to a depth of 100 nm with a B concentration of 0.05 at. %.

Enhanced EDX images by fusion of multimodal SEM images using pansharpening techniques.

PubMed

Franchi, G; Angulo, J; Moreaud, M; Sorbier, L

2018-01-01

The goal of this paper is to explore the potential interest of image fusion in the context of multimodal scanning electron microscope (SEM) imaging. In particular, we aim at merging the backscattered electron images that usually have a high spatial resolution but do not provide enough discriminative information to physically classify the nature of the sample, with energy-dispersive X-ray spectroscopy (EDX) images that have discriminative information but a lower spatial resolution. The produced images are named enhanced EDX. To achieve this goal, we have compared the results obtained with classical pansharpening techniques for image fusion with an original approach tailored for multimodal SEM fusion of information. Quantitative assessment is obtained by means of two SEM images and a simulated dataset produced by a software based on PENELOPE. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Permeable reactive barrier of coarse sand-supported zero valent iron for the removal of 2,4-dichlorophenol in groundwater.

PubMed

Gao, Weichun; Zhang, Yongxiang; Zhang, Xiaoye; Duan, Zhilong; Wang, Youhao; Qin, Can; Hu, Xiao; Wang, Hao; Chang, Shan

2015-11-01

In this study, coarse sand-supported zero valent iron (ZVI) composite was synthesized by adding sodium alginate to immobilize. Composite was detected by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). SEM results showed that composite had core-shell structure and a wide porous distribution pattern. The synthesized composite was used for degradation of 2,4-dichlorophenol (2,4-DCP) contamination in groundwater. Experimental results demonstrated that degradation mechanism of 2,4-DCP using coarse sand-supported ZVI included adsorption, desorption, and dechlorination. 2,4-DCP adsorption was described as pseudo-second-order kinetic model. It was concluded that dechlorination was the key reaction pathway, ZVI and hydrogen are prime reductants in dechlorination of 2,4-DCP using ZVI.

Crystallographic Study of Itokawa Particle, RA-QD02-0127 by Using Energy-Scanning X-Ray Diffraction Method with Synchrotron Radiation

NASA Technical Reports Server (NTRS)

Hagiya, K.; Ohsumi, K.; Komatsu, M.; Mikouchi, T.; Zolensky, M. E.; Hirata, A.; Yamaguchi, S.; Kurokawa, A.

2016-01-01

The petrographic study of Itokawa particle, RA-QD02-0127 has been performed by SEM-EDS and optical microscope observations. The purpose of this study is to understand better the metamorphic and impact shock history of asteroid Itokawa, and other S-class asteroids.

Optical, Magnetic and Photocatalytic Activity Studies of Li, Mg and Sr Doped and Undoped Zinc Oxide Nanoparticles.

PubMed

Shanthi, S I; Poovaragan, S; Arularasu, M V; Nithya, S; Sundaram, R; Magdalane, C Maria; Kaviyarasu, K; Maaza, M

2018-08-01

Nanoparticles of Li, Mg and Sr doped and undoped zinc oxide was prepared by simple precipitation method. The structural, optical, and magnetic properties of the samples were investigated by the Powder X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR) spectroscopy, Ultra-violet Visible spectroscopy (UV-vis) spectra, Photoluminescence (PL) and Vibrational Sample Magnetometer (VSM). The Powder X-ray diffraction data confirm the formation of hexagonal wurtzite structure of all doped and undoped ZnO. The SEM photograph reveals that the pores availability and particles size in the range of 10 nm-50 nm. FTIR and UV-Visible spectra results confirm the incorporation of the dopant into the ZnO lattice nanostructure. The UV-Visible spectra indicate that the shift of blue region (lower wavelength) due to bandgap widening. Photoluminescence intensity varies with doping due to the increase of oxygen vacancies in prepared ZnO. The pure ZnO exist paramagnetic while doped (Li, Mg and Sr) ZnO exist ferromagnetic property. The photocatalytic activity of the prepared sample also carried out in detail.

Direct-write maskless lithography using patterned oxidation of Si-substrate Induced by femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Kiani, Amirkianoosh; Venkatakrishnan, Krishnan; Tan, Bo

2013-03-01

In this study we report a new method for direct-write maskless lithography using oxidized silicon layer induced by high repetition (MHz) ultrafast (femtosecond) laser pulses under ambient condition. The induced thin layer of predetermined pattern can act as an etch stop during etching process in alkaline etchants such as KOH. The proposed method can be leading to promising solutions for direct-write maskless lithography technique since the proposed method offers a higher degree of flexibility and reduced time and cost of fabrication which makes it particularly appropriate for rapid prototyping and custom scale manufacturing. A Scanning Electron Microscope (SEM), Micro-Raman, Energy Dispersive X-ray (EDX), optical microscope and X-ray diffraction spectroscopy (XRD) were used to evaluate the quality of oxidized layer induced by laser pulses.

Synergistic effect of tartaric acid with 2,6-diaminopyridine on the corrosion inhibition of mild steel in 0.5 M HCl

PubMed Central

Qiang, Yujie; Guo, Lei; Zhang, Shengtao; Li, Wenpo; Yu, Shanshan; Tan, Jianhong

2016-01-01

The inhibitive ability of 2,6-diaminopyridine, tartaric acid and their synergistic effect towards mild steel corrosion in 0.5 M HCl solution was evaluated at various concentrations using potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS), and weight loss experiments. Corresponding surfaces of mild steel were examined by atomic force microscope (AFM), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) analysis. The experimental results are in good agreement and reveal a favorable synergistic effect of 2,6-diaminopyridine with tartaric acid, which could protect mild steel from corrosion effectively. Besides, quantum chemical calculations and Monte Carlo simulation were used to clarify the inhibition mechanism of the synergistic effect. PMID:27628901

Silicone intraocular lens surface calcification in a patient with asteroid hyalosis.

PubMed

Matsumura, Kazuhiro; Takano, Masahiko; Shimizu, Kimiya; Nemoto, Noriko

2012-07-01

To confirm a substance presence on the posterior intraocular lens (IOL) surface in a patient with asteroid hyalosis. An 80-year-old man had IOLs for approximately 12 years. Opacities and neodymium-doped yttrium aluminum garnet pits were observed on the posterior surface of the right IOL. Asteroid hyalosis and an epiretinal membrane were observed OD. An IOL exchange was performed on 24 March 2008, and the explanted IOL was analyzed using a light microscope and a transmission electron microscope with a scanning electron micrograph and an energy-dispersive X-ray spectrometer for elemental analysis. To confirm asteroid hyalosis, asteroid bodies were examined with the ionic liquid (EtMeIm+ BF4-) method using a field emission scanning electron microscope (FE-SEM) with digital beam control RGB mapping. X-ray spectrometry of the deposits revealed high calcium and phosphorus peaks. Spectrometry revealed that the posterior IOL surface opacity was due to a calcium-phosphorus compound. Examination of the asteroid bodies using FE-SEM with digital beam control RGB mapping confirmed calcium and phosphorus as the main components. Calcium hydrogen phosphate dihydrate deposits were probably responsible for the posterior IOL surface opacity. Furthermore, analysis of the asteroid bodies demonstrated that calcium and phosphorus were its main components.

Synthesis and dc electrical conductivity of Cr-doped CeO2 nanoparticles by solution combustion method

NASA Astrophysics Data System (ADS)

Harish, B. M.; Avinash, B. S.; Chaturmukha, V. S.; Jayanna, H. S.; Suresh, S.; Naveen, C. S.; Lamani, Ashok R.

2018-04-01

NPs of Ce1-xCrxO2 (x=0, 0.04, 0.08, 0.12) have been synthesized by solution combustion method using glycine as fuel. The effect of chromium on structural and dc electrical conductivity of cerium oxide nanoparticles were investigated. The obtained powder is characterized by UV-visible spectrometer, X-ray diffractometer (XRD), Scanning electron microscope (SEM) and Energy dispersive X-Ray analysis (EDS). X-ray diffraction analysis carried out on calcined samples reveals that successful incorporation of Cr2+ in CeO2 lattice where as SEM studies confirms the porous morphological structure of the prepared sample. The Keithley source meter is used to measure the dc conductivity of samples in the temperature range from 303K to 623K. The conductivity was found to be increases with increase of temperature as well as the Cr concentration due to semiconducting behavior of material and change in the charge carrier concentration. The activation energy decreases with increasing chromium concentration. The present work deals with the effect of chromium additive on structural and the D.C electrical properties Ce1-xCrxO2 NPs.

Three dimensional profile measurement using multi-channel detector MVM-SEM

NASA Astrophysics Data System (ADS)

Yoshikawa, Makoto; Harada, Sumito; Ito, Keisuke; Murakawa, Tsutomu; Shida, Soichi; Matsumoto, Jun; Nakamura, Takayuki

2014-07-01

In next generation lithography (NGL) for the 1x nm node and beyond, the three dimensional (3D) shape measurements such as side wall angle (SWA) and height of feature on photomask become more critical for the process control. Until today, AFM (Atomic Force Microscope), X-SEM (cross-section Scanning Electron Microscope) and TEM (Transmission Electron Microscope) tools are normally used for 3D measurements, however, these techniques require time-consuming preparation and observation. And both X-SEM and TEM are destructive measurement techniques. This paper presents a technology for quick and non-destructive 3D shape analysis using multi-channel detector MVM-SEM (Multi Vision Metrology SEM), and also reports its accuracy and precision.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Thomas Martin; Patton, Bruce W.; Weber, Charles F.

The primary goal of this project is to evaluate x-ray spectra generated within a scanning electron microscope (SEM) to determine elemental composition of small samples. This will be accomplished by performing Monte Carlo simulations of the electron and photon interactions in the sample and in the x-ray detector. The elemental inventories will be determined by an inverse process that progressively reduces the difference between the measured and simulated x-ray spectra by iteratively adjusting composition and geometric variables in the computational model. The intended benefit of this work will be to develop a method to perform quantitative analysis on substandard samplesmore » (heterogeneous phases, rough surfaces, small sizes, etc.) without involving standard elemental samples or empirical matrix corrections (i.e., true standardless quantitative analysis).« less

Tropical sea snail shells: Possible exotic sources for ceramic biomaterial synthesis

NASA Astrophysics Data System (ADS)

Oktar, F. N.; Kiyici, I. A.; Gökçe, H.; Aǧaogulları, D.; Kayali, E. S.

2013-12-01

In this study, chemical and structural properties of sea snail shell based bioceramic materials (i.e. hydroxyapatite, whitlockite and other phases) are produced by using mechano-chemical (ultrasonic) conversion method. For this purpose, differential thermal and gravimetric analysis (DTA/TG), X-ray diffraction, infra-red (IR) and scanning electron microscope (SEM) studies are performed.

Total rate imaging with x-rays (TRIX)--a simple method of forming a non-projection x-ray image in the SEM using an energy dispersive detector and its application to biological specimens.

PubMed

Ingram, P; Shelburne, J D

1980-01-01

X-ray images can be formed in a conventional scanning electron microscope equipped with a Si(Li) energy dispersive spectrometer. All the x-ray events generated in the electron beam scanning process are synchronously displayed in the same manner as for dot maps. The quasi-digital image formed using Total Rate Imaging with X-rays (TRIX) exhibits good gray scale contrast and is dependent on topography, orientation and atomic number. Although this latter dependence is complex, it has been found useful in locating several types of inclusions in lung tissue (silicosis), human alveolar macrophages and cigarette smoke condensate. This is because of the greater depth of penetration of x-rays than backscattered electrons (BSE) usually used for such localizations in a matrix, and the negligible sensitivity of the Si(Li) detector to x-rays from an organic biological matrix. The optimum procedure is to use a combination of TRIX and BSE to investigate such specimens.

Boehmite nanostructures preparation by hydrothermal method from anodic aluminium oxide membrane.

PubMed

Yang, X; Wang, J Y; Pan, H Y

2009-02-01

Boehmite nanostructures were successfully synthesized from porous anodic aluminium oxide (AAO) membrane by a simple and efficient hydro-thermal method. The experiment used high purity alumina as raw material, and the whole reaction process avoided superfluous impurities to be introduced. Thus, the purity of Boehmite products was ensured. The examinations of the morphology and structure were carried out by atomic force microscope (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Composition of the specimens was analyzed using energy dispersive X-ray spectroscope (EDX) and X-ray diffraction (XRD). Based on these observations the growth process was analyzed.

Composition and microstructure of MTA and Aureoseal Plus: XRF, EDS, XRD and FESEM evaluation.

PubMed

Cianconi, L; Palopoli, P; Campanella, V; Mancini, M

2016-12-01

The aim of this study was to determine the chemical composition and the phases' microstructure of Aureoseal Plus (OGNA, Italy) and ProRoot MTA (Dentsply Tulsa Dental, USA) and to compare their characteristics. Study Design: Comparing Aureoseal Plus and ProRoot MTA microstructure by means of several analyses type. The chemical analysis of the two cements was assessed following the UNI EN ISO 196-2 norm. X-Ray fluorescence (XRF) was used to determine the element composition. The crystalline structure was analysed quantitatively using x-ray diffraction (XRD). Powders morphology was evaluated using a scanning electron microscope (SEM) with backscattering detectors, and a field emission scanning electron microscope (FESEM). Elemental analysis was performed by energy dispersive x-ray analysis (EDS). The semi-quantitative XRF analysis showed the presence of heavy metal oxides in both cements. The XRD spectra of the two cements reported the presence of dicalcium silicate, tricalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite, bismuth oxide and gypsum. SEM analysis showed that ProRoot MTA powder is less coarse and more homogeneous than Aureoseal. Both powders are formed by particles of different shapes: round, prismatic and oblong. The EDS analysis showed that some ProRoot MTA particles, differently from Aureoseal, contain Ca, Si, Al and Fe. Oblong particles in ProRoot and Aureoseal are rich of bismuth. The strong interest in developing new Portland cement-based endodontic sealers will create materials with increased handling characteristics and physicochemical properties. A thorough investigation on two cement powders was carried out by using XRF, XRD, SEM and EDS analysis. To date there was a lack of studies on Aureoseal Plus. This cement is similar in composition to ProRoot MTA. Despite that it has distinctive elements that could improve its characteristics, resulting in a good alternative to MTA.

Direct laser sintered WC-10Co/Cu nanocomposites

NASA Astrophysics Data System (ADS)

Gu, Dongdong; Shen, Yifu

2008-04-01

In the present work, the direct metal laser sintering (DMLS) process was used to prepare the WC-Co/Cu nanocomposites in bulk form. The WC reinforcing nanoparticles were added in the form of WC-10 wt.% Co composite powder. The microstructural features and mechanical properties of the laser-sintered sample were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDX), and nanoindentation tester. It showed that the original nanometric nature of the WC reinforcing particulates was well retained without appreciable grain growth after laser processing. A homogeneous distribution of the WC reinforcing nanoparticles with a coherent particulate/matrix interfacial bonding was obtained in the laser-sintered structure. The 94.3% dense nanocomposites have a dynamic nanohardness of 3.47 GPa and a reduced elastic modulus of 613.42 GPa.

Synthesis and characterization of Ag@polycarbazole coaxial nanocables and their enhanced dispersion behavior

NASA Astrophysics Data System (ADS)

Zahoor, Ahmad; Teng, Qiu; Wang, Haiqiao; Choudhry, M. A.; Li, Xiaoyu

2011-06-01

Ag@polycarbazole coaxial nanocables (CNCs) have been successfully fabricated by the oxidative polymerization of carbazole over Ag nanowires (NWs) in acetonitrile. The morphology of Ag NWs and CNCs was studied by employing a transmission electron microscope (TEM) and a scanning electron microscope (SEM), which showed them to be a monodisperse material. The thickness of the polymer sheath was found to be 5 nm to 8 nm by observation under a high-resolution transmission electron microscope (HR-TEM). Energy dispersive X-ray spectroscopy (EDS), FT-IR and Raman measurements were used to characterize the polymer sheath, which demonstrated it to be a carbon material in polycarbazole form. X-ray photoelectron spectroscopy (XPS) was used for an interfacial study, which revealed that Ag surface atoms remained intact during polymer growth. In the end, zeta potential showed that the dispersion stability of Ag NWs increased due to polymer encapsulation, which is significant to obtain a particular alignment for anisotropic measurement of electrical conductivity.

Novel perovskite coating of strontium zirconate in Inconel substrate

NASA Astrophysics Data System (ADS)

Venkatesh, G.; Blessto, B.; Rao, C. Santhosh Kumar; Subramanian, R.; Berchmans, L. John

2018-02-01

Thermal Barrier Coatings (TBC) provides a low thermal conductivity barrier to heat transfer from the hot gas in the engine to the surface of the coated alloy component. SrZrO3 powder are prepared by Sol Gel synthesis method. The synthesized powder sample is characterized by X Ray Diffraction Technique (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) and the results are interpreted. The Polycrystalline nature of SrZrO3 is confirmed and lattice spacing are determined in XRD. SEM shows sub-micron sized particles and a fringed pattern is observed in TEM. The IN718 specimen is Wire Cut and Sand Blasted. A SrZrO3 double layer is coated over the Inconel specimen through a Bond Coat made of NiCoCrAlY by Plasma spraying Process and also characterized. SEM analysis of the Coating shows diffusion of Fe, Sr into the substrate.

Non-destructive determination of thickness of the dielectric layers using EDX

NASA Astrophysics Data System (ADS)

Sokolov, S. A.; Kelm, E. A.; Milovanov, R. A.; Abdullaev, D. A.; Sidorov, L. N.

2016-12-01

In this work a non-destructive method for measuring the thickness of the dielectric layers consisting of silicon dioxide and silicon nitride has been developed using a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDS). Rising in accelerating voltage of electron beam leads to increasing in the depth of generation of the characteristic X-ray. If the ratio of the signal intensity of one of the substrate's elements to the noise equal to 3 suggests that the generation's depth of the characteristic X-ray coincides with the thickness of the overlying film. Dependence of the overlying film's thickness on the accelerating voltage can be plotted. Validation of the results was carried out by using the equation of Anderson-Hassler. The generation's volume of the characteristic X-Ray was simulated by CASINO program. The simulations results are in good agreement with experimental results for small thicknesses.

Role of Bi3+ substitution on structural, magnetic and optical properties of cobalt spinel ferrite

NASA Astrophysics Data System (ADS)

Anjum, Safia; Sehar, Fatima; Awan, M. S.; Zia, Rehana

2016-04-01

Bismuth-doped cobalt ferrite CoBi x Fe(2- x)O4 with x = 0, 0.1,0.2, 0.3, 0.4, 0.5 have been prepared using powder metallurgy route. The structural, morphological, elemental, magnetic and optical properties have been investigated using X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-rays, vibrating sample magnetometer and ultraviolet-visible spectrometer, respectively. X-ray diffractometer analysis confirms the formation of single-phase cubic spinel structure. As the substitution of larger ionic radii Bi3+ ions increases in cobalt ferrite which is responsible to increase the lattice parameters and decrease the crystallite size. SEM micrographs revealed the spherical shape of the particles with the nonuniform grain boundaries. The saturation magnetization decreases and bandgap energy increases as the concentration of non-magnetic Bi3+ ions increases.

Synthesis of N-doped potassium tantalate perovskite material for environmental applications

NASA Astrophysics Data System (ADS)

Rao, Martha Purnachander; Nandhini, Vellangattupalayam Ponnusamy; Wu, Jerry J.; Syed, Asad; Ameen, Fuad; Anandan, Sambandam

2018-02-01

Nitrogen containing potassium tantalate perovskite material has been synthesized by the solvothermal method using urea (CH4N2O) as a nitrogen source. The as-prepared sample was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The particle size of nitrogen containing KTaO3 observed from SEM images was found to be 100-150 nm. Doping KTaO3 with nitrogen causes reduction of band gap from 3.5 to 2.54 eV. The incorporation of Nitrogen into the crystal lattice of KTaO3 not only extended the absorption of light from UV (ultraviolet) region to visible region and also enhanced the photocatalytic activity. As prepared nitrogen containing KTaO3 samples exhibit cubic-like morphology and noticed efficient photocatalytic activity towards methylene blue dye degradation under visible light illumination. The intermediates formed during photodegradation were identified by mass spectrometry (GC-MS) and proposed suitable degradation pathway.

Young's modulus and SEM analysis of leg bones exposed to simulated microgravity by hind limb suspension (HLS)

NASA Astrophysics Data System (ADS)

Patel, Niravkumar D.; Mehta, Rahul; Ali, Nawab; Soulsby, Michael; Chowdhury, Parimal

2013-04-01

The aim of this study was to determine composition of the leg bone tissue of rats that were exposed to simulated microgravity by Hind-Limb Suspension (HLS) by tail for one week. The leg bones were cross sectioned, cleaned of soft tissues, dried and sputter coated, and then placed horizontally on the stage of a Scanning Electron Microscope (SEM) for analysis. Interaction of a 17.5 keV electron beam, incident from the vertical direction on the sample, generated images using two detectors. X-rays emitted from the sample during electron bombardment were measured with an Energy Dispersive Spectroscopy (EDS) feature of SEM using a liquid-nitrogen cooled Si(Li) detector with a resolution of 144 eV at 5.9 keV (25Mn Kα x-ray). Kα- x-rays from carbon, oxygen, phosphorus and calcium formed the major peaks in the spectrum. Relative percentages of these elements were determined using a software that could also correct for ZAF factors namely Z(atomic number), A(X-ray absorption) and F(characteristic fluorescence). The x-rays from the control groups and from the experimental (HLS) groups were analyzed on well-defined parts (femur, tibia and knee) of the leg bone. The SEM analysis shows that there are definite changes in the hydroxyl or phosphate group of the main component of the bone structure, hydroxyapatite [Ca10(PO4)6(OH)2], due to hind limb suspension. In a separate experiment, entire leg bones (both from HLS and control rats) were subjected to mechanical stress by mean of a variable force. The stress vs. strain graph was fitted with linear and polynomial function, and the parameters reflecting the mechanical strength of the bone, under increasing stress, were calculated. From the slope of the linear part of the graph the Young's modulus for HLS bones were calculated and found to be 2.49 times smaller than those for control bones.

High-compactness coating grown by plasma electrolytic oxidation on AZ31 magnesium alloy in the solution of silicate-borax

NASA Astrophysics Data System (ADS)

Shen, M. J.; Wang, X. J.; Zhang, M. F.

2012-10-01

A ceramic coating was formed on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation (PEO) in the silicate solution with and without borax doped. The composition, morphology, elements and roughness as well as mechanical property of the coating were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reciprocal-sliding tribometer. The results show that the PEO coating is mainly composed of magnesia. When using borax dope, boron element is permeating into the coating and the boron containing phase exist in the form of amorphous. In addition, the microhardness and compactness of the PEO coating are improved significantly due to doped borax.

Incorporation of Tin on copper clad laminate to increase the interface adhesion for signal loss reduction of high-frequency PCB lamination

NASA Astrophysics Data System (ADS)

Wang, Chong; Wen, Na; Zhou, Guoyun; Wang, Shouxu; He, Wei; Su, Xinhong; Hu, Yongsuan

2017-11-01

A novel method of improving the adhesion between copper and prepreg in high frequency PCB was proposed and studied in this work. This process which aimed to decrease the IEP (isoelectric point) of the copper to obtain higher adhesion, was achieved by depositing a thin tin layer with lower IEP on copper. It was characterized by scanning electron microscopy (SEM), 3D microscope, peel strength test, X-Ray thickness test, grazing incidence X-ray diffraction (GXRD), X-ray photoelectron spectroscopy (XPS), Agilent vector network analyzer (VNA), which confirmed its excellent adhesion performance and outstanding electrical properties in high-frequency signal transmission compared with traditional brown oxide method. Moreover, the mechanism of achieving high adhesion for this method was also investigated.

Design of a normal incidence multilayer imaging X-ray microscope

NASA Astrophysics Data System (ADS)

Shealy, David L.; Gabardi, David R.; Hoover, Richard B.; Walker, Arthur B. C., Jr.; Lindblom, Joakim F.

Normal incidence multilayer Cassegrain X-ray telescopes were flown on the Stanford/MSFC Rocket X-ray Spectroheliograph. These instruments produced high spatial resolution images of the sun and conclusively demonstrated that doubly reflecting multilayer X-ray optical systems are feasible. The images indicated that aplanatic imaging soft X-ray/EUV microscopes should be achievable using multilayer optics technology. A doubly reflecting normal incidence multilayer imaging X-ray microscope based on the Schwarzschild configuration has been designed. The design of the microscope and the results of the optical system ray trace analysis are discussed. High resolution aplanatic imaging X-ray microscopes using normal incidence multilayer X-ray mirrors should have many important applications in advanced X-ray astronomical instrumentation, X-ray lithography, biological, biomedical, metallurgical, and laser fusion research.

X-ray laser microscope apparatus

DOEpatents

Suckewer, Szymon; DiCicco, Darrell S.; Hirschberg, Joseph G.; Meixler, Lewis D.; Sathre, Robert; Skinner, Charles H.

1990-01-01

A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

Laser ablation of Au-CuO core-shell nanocomposite in water for optoelectronic devices

NASA Astrophysics Data System (ADS)

Ismail, Raid A.; Abdul-Hamed, Ryam S.

2017-12-01

Core-shell gold-copper oxide Au-CuO nanocomposites were synthesized using laser ablation of CuO target in colloidal solution of Au nanoparticles (NPs). The effect of laser fluence on the structural, morphological, electrical, and optical properties of Au-CuO nanocomposites was investigated using x-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL), Fourier transformed infrared spectroscopy (FTIR), Hall measurement, and UV-vis spectroscopy. X-ray diffraction results confirm the formation of polycrystalline Au-CuO NPs with monoclinic structure. The optical energy gap for CuO was 4 eV and for the Au-CuO core-shell nanocomposites was found to be in the range of 3.4-3.7 eV. SEM and TEM investigations revealed that the structure and morphology of Au-CuO core-shell nanocomposites were strongly depending on the laser fluence. A formation of Au-CuO nanospheres and platelets structures was observed. The photoluminescence data showed an emission of broad visible peaks between 407 and 420 nm. The effect of laser fluence on the dark and illuminated I-V characteristics of Au-CuO/n-Si heterojunction photodetectors was investigated and analyzed. The experimental data demonstrated that the photodetector prepared at optimum laser fluence exhibited photosensitivity of 0.6 AW-1 at 800 nm.

Evaluation of correlation between dissolution rates of loxoprofen tablets and their surface morphology observed by scanning electron microscope and atomic force microscope.

PubMed

Yoshikawa, Shinichi; Murata, Ryo; Shida, Shigenari; Uwai, Koji; Suzuki, Tsuneyoshi; Katsumata, Shunji; Takeshita, Mitsuhiro

2010-01-01

We observed the surface morphological structures of 60 mg tablets of Loxonin, Loxot, and Lobu using scanning electron microscope (SEM) and atomic force microscope (AFM) to evaluate the dissolution rates. We found a significant difference among the initial dissolution rates of the three kinds of loxoprofen sodium tablets. Petal forms of different sizes were commonly observed on the surface of the Loxonin and Loxot tablets in which loxoprofen sodium was confirmed by measuring the energy-dispersible X-ray (EDX) spectrum of NaKalpha using SEM. However, a petal form was not observed on the surface of the Lobu tablet, indicating differences among the drug production processes. Surface area and particle size of the principal ingredient in tablets are important factors for dissolution rate. The mean size of the smallest fine particles constituting each tablet was also determined with AFM. There was a correlation between the initial dissolution rate and the mean size of the smallest particles in each tablet. Visualizing tablet surface morphology using SEM and AFM provides information on the drug production processes and initial dissolution rate, and is associated with the time course of pharmacological activities after tablet administration.

Hierarchical MnO2 nanosheets synthesized via electrodeposition-hydrothermal method for supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Zheng, Dongdong; Qiang, Yujie; Xu, Shenying; Li, Wenpo; Yu, Shanshan; Zhang, Shengtao

2017-02-01

Metal oxides have emerged as one kind of important supercapacitor electrode materials. Herein, we report hierarchical MnO2 nanosheets prepared of indium tin oxide (ITO) coated glass substrates via a hybrid two-step protocol, including a cathodic electrodeposition technique and a hydrothermal process. The samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX), and transmission electron microscope (TEM). SEM and TEM images show that the as-synthesized MnO2 nanosheets are hierarchical and porous, which could increase the active surface and short paths for fast ion diffusion. The results of nitrogen adsorption-desorption analysis indicate that the BET surface area of the MnO2 nanosheets is 53.031 m2 g-1. Furthermore, the electrochemical properties of the MnO2 are elucidated by cyclic voltammograms (CV), galvanostatic charge-discharge (GCD) tests, and electrochemical impedance spectroscopy (EIS) in 0.1 M Na2SO4 electrolyte. The electrochemical results demonstrate that the as-grown MnO2 nanosheet exhibits an excellent specific capacitance of 335 F g-1 at 0.5 A g-1 when it is applied as a potential electrode material for an electrochemical supercapacitor. Additionally, the MnO2 nanosheet electrode also presents high rate capability and good cycling stability with 91.8% retention after 1000 cycles. These excellent properties indicate that the hierarchical MnO2 nanosheets are a potential electrode material for electrochemical supercapacitors.

[Effects of dynamic high-pressure microfluidization on the structure of waxy rice starch].

PubMed

Tu, Zong-Cai; Zhu, Xiu-Mei; Chen, Gang; Wang, Hui; Zhang, Bo; Huang, Xiao-Qin; Li, Zhi

2010-03-01

The effects of dynamic ultra high-pressure microfluidization on the structure of waxy rice starch solutions (6%) were analyzed using SEM, UV-Vis spectra, polarized light microscopy, and X-ray diffraction spectra. The results showed that: SEM graphs demonstrated that the crystal structure of waxy rice starch under different pressure treatment was destroyed with different degrees and impacted into flake up to 160 MPa; from the ultraviolet-visible spectrum we know the reduction in the blue iodine value and the decrease in the amylopectin content, which illustrated that the structure of waxy rice starch was fractured; polarized microscopic images showed that the polarization crosses of starch molecules became misty with the pressure increasing, and most of starch molecules lost polarization cross when the pressure reached 160 MPa; X-ray diffraction spectra indicated that relative crystallinity began to decline at 120 MPa with pressure treatment, and the decreased amplitude was slightly lower.

Investigation of tin oxide nanofibers synthesized via bio-template technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kundu, Virender Singh, E-mail: vskundu-kuk@rediffmail.com; Dhiman, Jonny; Kumar, Suresh

In the present paper tin oxide nanofibers have been by synthesized using cotton as bio-template via sol-gel route. This is comparatively a new synthesis technique. The structure and morphology of the obtained SnO{sub 2} nanofibers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX). The optical properties of the same have been studied by using UV-Vis spectroscopy. The observed XRD pattern showed that peaks are very narrow and sharp which indicates crystalline nature of samples. SEM images gave an idea about the sample morphology and confirm that the obtained sample were nanofibers. The optical absorbancemore » spectrum of the sample under study was recorded in UV-visible region (200nm- 800nm). The band gap of the sample was found to be 3.95 eV which is higher than their bulk counterpart.« less

Enhancement in surface area and magnetization of CoFe2O4 nanoparticles for targeted drug delivery application

NASA Astrophysics Data System (ADS)

Kale, Swati B.; Somvanshi, Sandeep B.; Sarnaik, M. N.; More, S. D.; Shukla, S. J.; Jadhav, K. M.

2018-05-01

This paper reports facile synthesis, characterizations by X-ray diffraction and scanning electron microscopy and magnetic behaviour of cobalt ferrite nanoparticles. Cobalt ferrite nanoparticles were prepared by sol-gel auto combustion technique using glycine as a fuel. Phase purity and nanocrystalline nature of the prepared sample was confirmed through X-ray diffraction technique. No extra peak other than cubic spinel structure was observed in the XRD pattern. The crystallite size calculated by using Scherrer's formula is of the order of 21.6 nm indicating the nanocrystalline nature of the prepared cobalt ferrite sample. The surface morphological studies were carried out using scanning electron microscope (SEM). SEM image shows homogeneous, agglomerated particles with sponge-like form. The saturation magnetization, coercivity and remenance magnetization obtained by hysteresis curve clearly gives the evidence of excellent and enhanced magnetic behaviour.

Simultaneous recovery of phosphorus and potassium as magnesium potassium phosphate from synthetic sewage sludge effluent.

PubMed

Nakao, Satoshi; Nishio, Takayuki; Kanjo, Yoshinori

2017-10-01

Bench-scale experiments were performed to investigate simultaneous recovery of phosphorus and potassium from synthetic sewage sludge effluent as crystals of magnesium potassium phosphate (MPP or struvite-(K), MgKPO 4 ·6H 2 O). The optimal pH of MPP formation was 11.5. A phosphorus level of at least 3 mM and K:P molar ratio over 3 were necessary to form MPP, which showed higher content rate of phosphorus and potassium in precipitate. MPP crystallization was confirmed by analysing the precipitates using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) apparatus and an X-ray Diffractometer (XRD). Inhibition of MPP crystallization by iron and aluminium was confirmed by precipitation experiments and SEM-EDX analysis. Potassium ratio against magnesium in precipitate decreased for iron concentrations greater than over 0.2 mM and aluminium concentrations over 0.05 mM.

Surface modification of tooth root canal after application of an X-ray opaque waveguide

NASA Astrophysics Data System (ADS)

Dostálová, T.; Jelínková, H.; Šulc, J.; Němec, M.; Koranda, P.; Bartoňová, M.; Radina, P.; Miyagi, M.; Shi, Y.-W.; Matsuura, Y.

The interest in endodontic use of dental laser systems has been increasing. With the development of thin and flexible delivery systems for various wavelengths, laser applications in endodontics may become even more desirable. The aim of this study is to check the X-ray opacity of a hollow waveguide and to observe the results after laser root canal treatment. The root canal systems of 10 molars were treated endodontically by laser. For the laser radiation source, an Er:YAG laser system generating a wavelength of 2940 nm and an Alexandrite laser system generating a wavelength of 375 nm were used. The hollow waveguide used was checked under X-ray . A root canal surface treated by laser radiation was analyzed by a scanning electron microscope (SEM). The special hollow glass waveguide used was visible in the root canal system under X-ray imaging. Surface modification of the root canal after laser treatment was not found. After conventional treatment the root canal was enlarged. The surface was covered with a smear layer. After application of both laser systems, the smear layer was removed. The resulting canal surface was found to be clean and smooth. Under SEM observation open dentinal tubules were visible. No cracks were present, nor were surface modifications observed.

Effect of cadmium incorporation on the properties of zinc oxide thin films

NASA Astrophysics Data System (ADS)

Bharath, S. P.; Bangera, Kasturi V.; Shivakumar, G. K.

2018-02-01

Cd x Zn1- x O (0 ≤ x ≤ 0.20) thin films are deposited on soda lime glass substrates using spray pyrolysis technique. To check the thermal stability, Cd x Zn1- x O thin films are subjected to annealing. Both the as-deposited and annealed Cd x Zn1- x O thin films are characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDAX) to check the structural, surface morphological and compositional properties, respectively. XRD analysis reveals that the both as-deposited and annealed Cd x Zn1- x O thin films are (002) oriented with wurtzite structure. SEM studies confirm that as-deposited, as well as annealed Cd x Zn1- x O thin films are free from pinholes and cracks. Compositional analysis shows the deficiency in Cd content after annealing. Optical properties evaluated from UV-Vis spectroscopy shows red shift in the band gap for Cd x Zn1- x O thin films. Electrical property measured using two probe method shows a decrease in the resistance after Cd incorporation. The results indicate that cadmium can be successfully incorporated in zinc oxide thin films to achieve structural changes in the properties of films.

Characteristics of Volcanic Soils in Landslide during the 2016 Kumamoto Earthquake, Japan

NASA Astrophysics Data System (ADS)

Hazarika, H.; Fukuoka, H.; Kokusho, T.; Sumartini, O.; Bhoopendra, D.

2017-12-01

There were many seismic subsidence, debris flows, landslides and slope failures, which occurred in Aso area due to the 2016 Kumamoto earthquake, Japan. This research aims to determine the failure mechanism of many mild slopes, and elucidate the strength characteristics of volcanic soils collected from the sites. A series of undrained static and cyclic triaxial tests, ring shear tests and direct shear tests were performed. Also, for further understanding of volcanic soils' material strength, X-ray powder diffraction analysis (XRD), X-ray fluorescence analysis (XRF), and Scanning electron microscope analysis (SEM) were performed. In this paper, preliminary results of the experimental testing program are discussed.

Preparation and Optoelectrical Properties of p-CuO/n-Si Heterojunction by a Simple Sol-Gel Method

NASA Astrophysics Data System (ADS)

He, Bo; Xu, Jing; Ning, Huanpo; Zhao, Lei; Xing, Huaizhong; Chang, Chien-Cheng; Qin, Yuming; Zhang, Lei

The Cuprous oxide (CuO) thin film was prepared on texturized Si wafer by a simple sol-gel method to fabricate p-CuO/n-Si heterojunction photoelectric device. The novel sol-gel method is very cheap and convenient. The structural, optical and electrical properties of the CuO film were studied by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometer and Hall effect measurement. A good nonlinear rectifying behavior is obtained for the p-CuO/n-Si heterojunction. Under reverse bias, good photoelectric behavior is obtained.

Electron-excited energy dispersive x-ray spectrometry in the variable pressure scanning electron microscope (EDS/VPSEM): it's not microanalysis anymore!

NASA Astrophysics Data System (ADS)

Newbury, Dale E.; Ritchie, Nicholas W. M.

2015-10-01

X-ray spectra suffer significantly degraded spatial resolution when measured in the variable-pressure scanning electron microscope (VPSEM, chamber pressure 1 Pa to 2500 Pa) as compared to highvacuum SEM (operating pressure < 10 mPa). Depending on the gas path length, electrons that are scattered hundreds of micrometers outside the focused beam can contribute 90% or more of the measured spectrum. Monte Carlo electron trajectory simulation, available in NIST DTSA-II, models the gas scattering and simulates mixed composition targets, e.g., particle on substrate. The impact of gas scattering at the major (C > 0.1 mass fraction), minor (0.01 <= C <= 0.1), and trace (C < 0.01) constituent levels can be estimated. NIST DTSA-II for Java-platforms is available free at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

Algan/Gan Hemt By Magnetron Sputtering System

NASA Astrophysics Data System (ADS)

Garcia Perez, Roman

In this thesis, the growth of the semiconductor materials AlGaN and GaN is achieved by magnetron sputtering for the fabrication of High Electron Mobility Transistors (HEMTs). The study of the deposited nitrides is conducted by spectroscopy, diffraction, and submicron scale microscope methods. The preparation of the materials is performed using different parameters in terms of power, pressure, temperature, gas, and time. Silicon (Si) and Sapphire (Al2O3) wafers are used as substrates. The chemical composition and surface topography of the samples are analyzed to calculate the materials atomic percentages and to observe the devices surface. The instruments used for the semiconductors characterization are X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscope (AFM). The project focused its attention on the reduction of impurities during the deposition, the controlled thicknesses of the thin-films, the atomic configuration of the alloy AlxGa1-xN, and the uniformity of the surfaces.

Design of a normal incidence multilayer imaging x-ray microscope.

PubMed

Shealy, D L; Gabardi, D R; Hoover, R B; Walker, A B; Lindblom, J F; Barbee, T W

1989-01-01

Normal incidence multilayer Cassegrain x-ray telescopes were flown on the Stanford/MSFC Rocket X-Ray Spectroheliograph. These instruments produced high spatial resolution images of the Sun and conclusively demonstrated that doubly reflecting multilayer x-ray optical systems are feasible. The images indicated that aplanatic imaging soft x-ray /EUV microscopes should be achievable using multilayer optics technology. We have designed a doubly reflecting normal incidence multilayer imaging x-ray microscope based on the Schwarzschild configuration. The Schwarzschild microscope utilizes two spherical mirrors with concentric radii of curvature which are chosen such that the third-order spherical aberration and coma are minimized. We discuss the design of the microscope and the results of the optical system ray trace analysis which indicates that diffraction-limited performance with 600 Å spatial resolution should be obtainable over a 1 mm field of view at a wavelength of 100 Å. Fabrication of several imaging soft x-ray microscopes based upon these designs, for use in conjunction with x-ray telescopes and laser fusion research, is now in progress. High resolution aplanatic imaging x-ray microscopes using normal incidence multilayer x-ray mirrors should have many important applications in advanced x-ray astronomical instrumentation, x-ray lithography, biological, biomedical, metallurgical, and laser fusion research.

The Microstructure and Physical Properties of Incinerated Paper-Cullet-Clay Ceramics

NASA Astrophysics Data System (ADS)

Sahar, M. R.; Hamzah, K.; Rohani, M. S.; Samah, K. A.; Razi, M. M.

A series of ceramic based on (x) incinerated recycle paper - (80-x) cullet - 20 Kaolin clay (where 10×45 wt%) has successfully been made by slip casting technique followed by sintering at 1000 °C. The actual composition of ceramic is analyzed using Energy Dispersive of X-Ray (EDAX) while the phase existence is determined using X-Ray Diffraction (XRD) technique. Their microstructural morphology is observed under Scanning Electron Microscope (SEM) and the physical properties are measured in term of their thermal shrinkage and hardness. It is found that the ceramic contain mostly of Silica and the phase is dominated by the existence of Quartz (SiO2), Wollastonite (CaSiO3) and Anorthite (Ca(Al2SiO8)). The SEM micrograph shows that the morphology is dominated by the existence of granular structure, and then become smoother as the cullet level is further increased. It is also found out that the thermal shrinkage is in the range 18% - 6.5% while the hardness is in the range of 152MPa- 1.463 GPa depending on composition.

Visible light photocatalytic activities of template free porous graphitic carbon nitride-BiOBr composite catalysts towards the mineralization of reactive dyes

NASA Astrophysics Data System (ADS)

Kanagaraj, Thamaraiselvi; Thiripuranthagan, Sivakumar; Paskalis, Sahaya Murphin Kumar; Abe, Hideki

2017-12-01

Template free porous g-C3N4 (pGCN) and flower like bismuth oxybromide catalysts were synthesized by poly condensation and precipitation methods respectively. Various weight percentages of porous GCN-BiOBr composite catalysts (x% pGCN-BiOBr where x = 5, 10, 30, 50 & 70 wt% of pGCN) were synthesized by impregnation method. All the synthesized catalysts were characterized by X-Ray diffractometer, Fourier transform infrared spectrophotometer, BET surface area analyzer, UV Visible diffuse reflectance spectrophotometer, X-Ray photoelectron spectrophotometer, SEM with Energy dispersive X-ray analyzer (SEM/EDAX) and elemental mapping, Transmission electron microscope, Photoluminescence spectrophotometer and Electrochemical impedance. Photocatalytic degradation of all the synthesized catalysts were tested towards the harmful reactive dyes such as reactive blue 198 (RB 198), reactive black 5 (RB 5) and reactive yellow 145 (RY 145) in presence of visible irradiation. Among the catalysts 30% pGCN-BiOBr resulted in the highest photocatalytic activity towards the degradation of all the three dyes in presence of UV, visible and solar irradiations. Kinetics studies on the photocatalytic mineralization of dyes indicated that it followed pseudo first order. HPLC, TOC and COD studies confirm that the dyes are mineralized into CO2, water and mineral salts.

Structural and magnetic properties of chromium doped zinc ferrite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sebastian, Rintu Mary; Thankachan, Smitha; Xavier, Sheena

2014-01-28

Zinc chromium ferrites with chemical formula ZnCr{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by Sol - Gel technique. The structural as well as magnetic properties of the synthesized samples have been studied and reported here. The structural characterizations of the samples were analyzed by using X – Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The single phase spinel cubic structure of all the prepared samples was tested by XRD and FTIR. The particle size was observed to decrease from 18.636 nm to 6.125more » nm by chromium doping and induced a tensile strain in all the zinc chromium mixed ferrites. The magnetic properties of few samples (x = 0.0, 0.4, 1.0) were investigated using Vibrating Sample Magnetometer (VSM)« less

Macroscopic and microscopic variation in recovered magnesium phosphate materials: implications for phosphorus removal processes and product re-use.

PubMed

Massey, Michael S; Ippolito, James A; Davis, Jessica G; Sheffield, Ron E

2010-02-01

Phosphorus (P) recovery and re-use will become increasingly important for water quality protection and sustainable nutrient cycling as environmental regulations become stricter and global P reserves decline. The objective of this study was to examine and characterize several magnesium phosphates recovered from actual wastewater under field conditions. Three types of particles were examined including crystalline magnesium ammonium phosphate hexahydrate (struvite) recovered from dairy wastewater, crystalline magnesium ammonium phosphate hydrate (dittmarite) recovered from a food processing facility, and a heterogeneous product also recovered from dairy wastewater. The particles were analyzed using "wet" chemical techniques, powder X-ray diffraction (XRD), and scanning electron microscopy in conjunction with energy dispersive X-ray spectroscopy (SEM-EDS). The struvite crystals had regular and consistent shape, size, and structure, and SEM-EDS analysis clearly showed the struvite crystals as a surface precipitate on calcium phosphate seed material. In contrast, the dittmarite crystals showed no evidence of seed material, and were not regular in size or shape. The XRD analysis identified no crystalline magnesium phosphates in the heterogeneous product and indicated the presence of sand particles. However, magnesium phosphate precipitates on calcium phosphate seed material were observed in this product under SEM-EDS examination. These substantial variations in the macroscopic and microscopic characteristics of magnesium phosphates recovered under field conditions could affect their potential for beneficial re-use and underscore the need to develop recovery processes that result in a uniform, consistent product.

Cryotomography x-ray microscopy state

DOEpatents

Le Gros, Mark; Larabell, Carolyn A.

2010-10-26

An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

Diffusion length measurement using the scanning electron microscope. [for silicon solar cell

NASA Technical Reports Server (NTRS)

Weizer, V. G.

1975-01-01

The present work describes a measuring technique employing the scanning electron microscope in which values of the true bulk diffusion length are obtained. It is shown that surface recombination effects can be eliminated through application of highly doped surface field layers. The effects of high injection level and low-high junction current generation are investigated. Results obtained with this technique are compared to those obtained by a penetrating radiation (X-ray) method, and a close agreement is found. The SEM technique is limited to cells that contain a back surface field layer.

Resizing metal-coated nanopores using a scanning electron microscope.

PubMed

Chansin, Guillaume A T; Hong, Jongin; Dusting, Jonathan; deMello, Andrew J; Albrecht, Tim; Edel, Joshua B

2011-10-04

Electron beam-induced shrinkage provides a convenient way of resizing solid-state nanopores in Si(3) N(4) membranes. Here, a scanning electron microscope (SEM) has been used to resize a range of different focussed ion beam-milled nanopores in Al-coated Si(3) N(4) membranes. Energy-dispersive X-ray spectra and SEM images acquired during resizing highlight that a time-variant carbon deposition process is the dominant mechanism of pore shrinkage, although granular structures on the membrane surface in the vicinity of the pores suggest that competing processes may occur. Shrinkage is observed on the Al side of the pore as well as on the Si(3) N(4) side, while the shrinkage rate is observed to be dependent on a variety of factors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ORIGIN OF QUARTZ IN COAL.

USGS Publications Warehouse

Ruppert, Leslie F.; Cecil, C. Blaine; Stanton, Ronald W.

1984-01-01

Both a scanning electron microscope and an electron microprobe (EMP) were used in this study to analyze the cathodoluminescence properties of quartz grains in samples of the Upper Freeport coal bed because quartz grains in coal are small (silt sized) and below the resolution capabilities of a standard luminoscope. Quartz grains were identified by the detection of silicon alone with energy dispersive X-ray units attached to both the SEM and the EMP.

Evolution processes of the corrosion behavior and structural characteristics of plasma electrolytic oxidation coatings on AZ31 magnesium alloy

NASA Astrophysics Data System (ADS)

Chen, Dong; Wang, Ruiqiang; Huang, Zhiquan; Wu, Yekang; Zhang, Yi; Wu, Guorui; Li, Dalong; Guo, Changhong; Jiang, Guirong; Yu, Shengxue; Shen, Dejiu; Nash, Philip

2018-03-01

Evolution processes of the corrosion behavior and structural characteristics of the plasma electrolytic oxidation (PEO) coated AZ31 magnesium alloy were investigated by using scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), potentio-dynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Detached coating samples were fabricated by an electrochemical method and more details of the internal micro-structure of coatings were clearly observed on the fractured cross-section morphologies of the samples compared to general polished cross-section morphologies. Evolution mechanisms of the coating corrosion behavior in relation to the evolution of micro-structural characteristics were discussed in detail.

[Biomimetic mineralization of rod-like cellulose nano-whiskers and spectrum analysis].

PubMed

Qu, Ping; Wang, Xuan; Cui, Xiao-xia; Zhang, Li-ping

2012-05-01

Cellulose nano-whiskers/nano-hydroxyapatite composite was prepared with biomimetic mineralization using rod-like cellulose nano-whiskers as template. The cellulose nano-whiskers and cellulose nano-whiskers/nano-hydroxyapatite composite were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope-energy dispersive analysis of X-rays (SEM-EDXA). Variation and distribution of carbon, oxygen, calcium, and phosphorus in the composites were studied. The morphologies and growth mechanism of nano-hydroxyapatite were analyzed. The results showed that nano-hydroxyapatite was formed on the surface of cellulose nano-whiskers; the carbon-oxygen ratio of cellulose nano-whiskers and cellulose nano-whiskers/nano-hydroxyapatite composite was 1.81 and 1.54, respectively; the calcium-phosphorus ratio of the composite was 1.70. The nucleation of nano-hydroxyapatite was around the hydroxyl groups of cellulose nano-whiskers. It is suggested that there is coordination between the hydroxyl groups of cellulose nano-whiskers and calcium ions of nano-hydroxyapatite. The nano-hydroxyapatite can distribute in the matrix of cellulose nano-whiskers. From the atomic force microscope (AFM) images, we can see that the diameter of the spherical nano-hydroxyapatite particles was about 20 nm.

X ray imaging microscope for cancer research

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

1991-01-01

The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research.

Simultaneous phase and morphology controllable synthesis of copper selenide films by microwave-assisted nonaqueous approach

NASA Astrophysics Data System (ADS)

Li, Jing; Fa, Wenjun; Li, Yasi; Zhao, Hongxiao; Gao, Yuanhao; Zheng, Zhi

2013-02-01

Copper selenide films with different phase and morphology were synthesized on copper substrate through controlling reaction solvent by microwave-assisted nonaqueous approach. The films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The result showed that the pure films could be obtained using cyclohexyl alcohol or benzyl alcohol as solvent. The cubic Cu2-xSe dendrites were synthesized in cyclohexyl alcohol reaction system and hexagonal CuSe flaky crystals were obtained with benzyl alcohol as solvent.

A critical study of the role of the surface oxide layer in titanium bonding

NASA Technical Reports Server (NTRS)

Dias, S.; Wightman, J. P.

1983-01-01

Scanning electron microscope/X-ray photoelectron spectroscopy (SEM/XPS) analysis of fractured adhesively bonded Ti 6-4 samples is discussed. The text adhesives incuded NR 056X polyimide, polypheylquinoxaline (PPQ), and LARC-13 polyimide. Differentiation between cohesive and interfacial failure was based on the absence of presence of a Ti 2p XPS photopeak. In addition, the surface oxide layer on Ti-(6A1-4V) adherends is characterized and bond strength and durability are addressed. Bond durability in various environmental conditions is discussed.

Young's modulus and SEM analysis of leg bones exposed to simulated microgravity by hind limb suspension (HLS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, Niravkumar D.; Mehta, Rahul; Ali, Nawab

2013-04-19

The aim of this study was to determine composition of the leg bone tissue of rats that were exposed to simulated microgravity by Hind-Limb Suspension (HLS) by tail for one week. The leg bones were cross sectioned, cleaned of soft tissues, dried and sputter coated, and then placed horizontally on the stage of a Scanning Electron Microscope (SEM) for analysis. Interaction of a 17.5 keV electron beam, incident from the vertical direction on the sample, generated images using two detectors. X-rays emitted from the sample during electron bombardment were measured with an Energy Dispersive Spectroscopy (EDS) feature of SEM usingmore » a liquid-nitrogen cooled Si(Li) detector with a resolution of 144 eV at 5.9 keV ({sub 25}Mn K{sub {alpha}} x-ray). K{sub {alpha}}- x-rays from carbon, oxygen, phosphorus and calcium formed the major peaks in the spectrum. Relative percentages of these elements were determined using a software that could also correct for ZAF factors namely Z(atomic number), A(X-ray absorption) and F(characteristic fluorescence). The x-rays from the control groups and from the experimental (HLS) groups were analyzed on well-defined parts (femur, tibia and knee) of the leg bone. The SEM analysis shows that there are definite changes in the hydroxyl or phosphate group of the main component of the bone structure, hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}], due to hind limb suspension. In a separate experiment, entire leg bones (both from HLS and control rats) were subjected to mechanical stress by mean of a variable force. The stress vs. strain graph was fitted with linear and polynomial function, and the parameters reflecting the mechanical strength of the bone, under increasing stress, were calculated. From the slope of the linear part of the graph the Young's modulus for HLS bones were calculated and found to be 2.49 times smaller than those for control bones.« less

Dopant concentration dependent optical and X-Ray induced photoluminescence in Eu3+ doped La2Zr2O7

NASA Astrophysics Data System (ADS)

Pokhrel, Madhab; Brik, Mikhail; Mao, Yuanbing

2015-03-01

Herein, we will be presenting the dopant (Eu) concentration dependent high density La2Zr2O7 nanoparticles for optical and X-ray scintillation applications by use of X - ray diffraction, Raman, FTIR, scanning electron microscope (SEM), transmission electron microscopy (TEM), optically and X-ray excited photoluminescence (PL). Several theoretical methods have been used in order to investigate the structural, electronic, optical, elastic, dynamic properties of Eu doped La2Zr2O7. It is observed that Eu: La2Zr2O7 shows an intense red luminescence under 258, 322, 394 and 465 nm excitation. The optical intensity of Eu: La2Zr2O7 depends on the dopant concentration of Eu3+. Following high energy excitation with X-rays, Eu: La2Zr2O7 shows an atypical Eu PL response (scintillation) with a red emission. The intense color emission of Eu obtained under 258 nm excitation, the X-ray induced luminescence property along with reportedly high density of La2Zr2O7, makes these nanomaterials attractive for optical and X-ray applications. The authors thank the support from the Defense Threat Reduction Agency (DTRA) of the U.S. Department of Defense (Award #HDTRA1-10-1-0114).

Chemical form analysis of reaction products in Cs-adsorption on stainless steel by means of HAXPES and SEM/EDX

NASA Astrophysics Data System (ADS)

Kobata, M.; Okane, T.; Nakajima, K.; Suzuki, E.; Ohwada, K.; Kobayashi, K.; Yamagami, H.; Osaka, M.

2018-01-01

In this study, for the understandings of Cesium (Cs) adsorption behavior on structure materials in severe accidents in a light water nuclear reactor, the chemical state of Cs and its distribution on the surface of SUS304 stainless steel (SS) with different Si concentrations was investigated by hard X-ray photoelectron spectroscopy (HAXPES) and scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDX). As a result, it was found that Cs is selectively adsorbed at the site where Si distributes with a high concentration. CsFeSiO4 is the dominant Cs products in case of low Si content, while Cs2Si2O5 and Cs2Si4O9 are formed in addition to CsFeSiO4 in case of high Si content. The chemical forms of the Cs compounds produced in the adsorption process on the SS surface have a close correlation with the concentration and chemical states of Si originally included in SS.

Progress toward Synthesis and Characterization of Rare-Earth Nanoparticles

NASA Astrophysics Data System (ADS)

Romero, Dulce G.; Ho, Pei-Chun; Attar, Saeed; Margosan, Dennis

2010-03-01

Magnetic nanoparticles exhibit interesting phenomena, such as enhanced magnetization and reduced magnetic ordering temperature (i.e. superparamagnetism), which has technical applications in industry, including magnetic storage, magnetic imaging, and magnetic refrigeration. We used the inverse micelle technique to synthesize Gd and Nd nanoparticles given its potential to control the cluster size, amount of aggregation, and prevent oxidation of the rare-earth elements. Gd and Nd were reduced by NaBH4 from the chloride salt. The produced clusters were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The results from the XRD show that the majority of the peaks match those of the surfactant, DDAB. No peaks of Gd were observed due to excess surfactant or amorphous clusters. However, the results from the SEM and EDX indicate the presence of Gd and Nd in our clusters microscopically, and current synthesized samples contain impurities. We are using liquid-liquid extraction method to purify the sample, and the results will be discussed.

Non Destructive 3D X-Ray Imaging of Nano Structures & Composites at Sub-30 NM Resolution, With a Novel Lab Based X-Ray Microscope

DTIC Science & Technology

2006-11-01

NON DESTRUCTIVE 3D X-RAY IMAGING OF NANO STRUCTURES & COMPOSITES AT SUB-30 NM RESOLUTION, WITH A NOVEL LAB BASED X- RAY MICROSCOPE S H Lau...article we describe a 3D x-ray microscope based on a laboratory x-ray source operating at 2.7, 5.4 or 8.0 keV hard x-ray energies. X-ray computed...tomography (XCT) is used to obtain detailed 3D structural information inside optically opaque materials with sub-30 nm resolution. Applications include

Focused ion beam (FIB)/scanning electron microscopy (SEM) in tissue structural research.

PubMed

Leser, Vladka; Milani, Marziale; Tatti, Francesco; Tkalec, Ziva Pipan; Strus, Jasna; Drobne, Damjana

2010-10-01

The focused ion beam (FIB) and scanning electron microscope (SEM) are commonly used in material sciences for imaging and analysis of materials. Over the last decade, the combined FIB/SEM system has proven to be also applicable in the life sciences. We have examined the potential of the focused ion beam/scanning electron microscope system for the investigation of biological tissues of the model organism Porcellio scaber (Crustacea: Isopoda). Tissue from digestive glands was prepared as for conventional SEM or as for transmission electron microscopy (TEM). The samples were transferred into FIB/SEM for FIB milling and an imaging operation. FIB-milled regions were secondary electron imaged, back-scattered electron imaged, or energy dispersive X-ray (EDX) analyzed. Our results demonstrated that FIB/SEM enables simultaneous investigation of sample gross morphology, cell surface characteristics, and subsurface structures. The same FIB-exposed regions were analyzed by EDX to provide basic compositional data. When samples were prepared as for TEM, the information obtained with FIB/SEM is comparable, though at limited magnification, to that obtained from TEM. A combination of imaging, micro-manipulation, and compositional analysis appears of particular interest in the investigation of epithelial tissues, which are subjected to various endogenous and exogenous conditions affecting their structure and function. The FIB/SEM is a promising tool for an overall examination of epithelial tissue under normal, stressed, or pathological conditions.

Low temperature nucleation of Griffiths Phase in Co doped LaMnO3 nanostructures

NASA Astrophysics Data System (ADS)

Adeela, N.; Khan, U.; Naz, S.; Iqbal, M.; Irfan, M.; Cheng, Y.

2017-11-01

We have reported magnetic properties of La1-xCoxMnO3 nanostructures synthesized by hydrothermal route. The crystal structure has been characterized by X-ray diffraction (XRD) technique, which shows rhombohedral perovskite structure at room temperature. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) have been used to analyse morphology and chemical composition of prepared nanoparticles. Magnetic hysteresis loops of all the samples exhibit ferromagnetic behaviour at 10 K. Inverse susceptibility graphs as a function of temperature represent deviation from Curie Weiss law. The indication for short range ferromagnetic clusters well above Curie temperature is observed due to the Griffiths Phase (GP). It is proposed that the presence of GP arises from induced size effects of La and Co ions.

Fabrication, characterization and gas sensing studies of PPy/MWCNT/SLS nanocomposite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tiwari, D. C., E-mail: dctiwari2001@yahoo.com; Atri, Priyanka, E-mail: dctiwari2001@yahoo.com; Sharma, R.

2014-04-24

Multiwall carbon nanotubes (MWCNT) coated with polypyrrole nanocomposite was prepared by in-situ chemical oxidative polymerization method in the presence of surfactant (SLS). The scanning electron microscope (SEM) pictures indicate the core shell structure of PPy/MWCNT/SLS nanocomposite. Nature of the prepared material was investigated by X-ray diffraction spectroscopy. This nanocomposite shows the excellent gas sensing behaviour for ammonia gas at 150 ppm and 300 ppm levels.

Removal of Micrometer Size Morphological Defects and Enhancement of Ultraviolet Emission by Thermal Treatment of Ga-Doped ZnO Nanostructures

PubMed Central

Manzoor, Umair; Kim, Do K.; Islam, Mohammad; Bhatti, Arshad S.

2014-01-01

Mixed morphologies of Ga-doped Zinc Oxide (ZnO) nanostructures are synthesized by vapor transport method. Systematic scanning electron microscope (SEM) studies of different morphologies, after periodic heat treatments, gives direct evidence of sublimation. SEM micrographs give direct evidence that morphological defects of nanostructures can be removed by annealing. Ultra Violet (UV) and visible emission depends strongly on the annealing temperatures and luminescent efficiency of UV emission is enhanced significantly with each subsequent heat treatment. X-Ray diffraction (XRD) results suggest that crystal quality improved by annealing and phase separation may occur at high temperatures. PMID:24489725

Removal of micrometer size morphological defects and enhancement of ultraviolet emission by thermal treatment of Ga-doped ZnO nanostructures.

PubMed

Manzoor, Umair; Kim, Do K; Islam, Mohammad; Bhatti, Arshad S

2014-01-01

Mixed morphologies of Ga-doped Zinc Oxide (ZnO) nanostructures are synthesized by vapor transport method. Systematic scanning electron microscope (SEM) studies of different morphologies, after periodic heat treatments, gives direct evidence of sublimation. SEM micrographs give direct evidence that morphological defects of nanostructures can be removed by annealing. Ultra Violet (UV) and visible emission depends strongly on the annealing temperatures and luminescent efficiency of UV emission is enhanced significantly with each subsequent heat treatment. X-Ray diffraction (XRD) results suggest that crystal quality improved by annealing and phase separation may occur at high temperatures.

Sensitive determination of citrinin based on molecular imprinted electrochemical sensor

NASA Astrophysics Data System (ADS)

Atar, Necip; Yola, Mehmet Lütfi; Eren, Tanju

2016-01-01

In this report, a novel molecular imprinted voltammetric sensor based on glassy carbon electrode (GCE) modified with platinum nanoparticles (PtNPs) involved in a polyoxometalate (H3PW12O40, POM) functionalized reduced graphene oxide (rGO) was prepared for the determination of citrinin (CIT). The developed surfaces were characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) method. CIT imprinted GCE was prepared via electropolymerization process of 80.0 mM pyrrole as monomer in the presence of phosphate buffer solution (pH 6.0) containing 20.0 mM CIT. The linearity range and the detection limit of the developed method were calculated as 1.0 × 10-12-1.0 × 10-10 M and 2.0 × 10-13 M, respectively. In addition, the voltammetric sensor was applied to rye samples. The stability and selectivity of the voltammetric sensor were also reported.

New molecular imprinted voltammetric sensor for determination of ochratoxin A.

PubMed

Yola, Mehmet Lütfi; Gupta, Vinod Kumar; Atar, Necip

2016-04-01

In this report, a novel molecular imprinted voltammetric sensor based on silver nanoparticles (AgNPs) involved in a polyoxometalate (H3PW12O40, POM) functionalized reduced graphene oxide (rGO) modified glassy carbon electrode (GCE) was presented for determination of ochrattoxin A (OCH). The developed surfaces were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) method. OCH imprinted GCE was prepared via electropolymerization process of 100mM phenol as monomer in the presence of phosphate buffer solution (pH6.0) containing 25 mM OCH. The linearity range and the detection limit of the method were calculated as 5.0 × 10(-11) - 1.5 × 10(-9)M and 1.6 × 10(-11) M, respectively. The voltammetric sensor was applied to grape juice and wine samples with good selectivity and recovery. The stability of the voltammetric sensor was also reported. Copyright © 2015 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gofron, K. J., E-mail: kgofron@bnl.gov; Cai, Y. Q.; Coburn, D. S.

A novel on-axis X-ray microscope with 3 µm resolution, 3x magnification, and a working distance of 600 mm for in-situ sample alignment and X-ray beam visualization for the Inelastic X-ray Scattering (IXS) beamline at NSLS-II is presented. The microscope uses reflective optics, which minimizes dispersion, and allows imaging from Ultraviolet (UV) to Infrared (IR) with specifically chosen objective components (coatings, etc.). Additionally, a portable high resolution X-ray microscope for KB mirror alignment and X-ray beam characterization was developed.

Synthesis of Zeolite-X from Bottom Ash for H2 Adsorption

NASA Astrophysics Data System (ADS)

Kurniawan, R. Y.; Romadiansyah, T. Q.; Tsamarah, A. D.; Widiastuti, N.

2018-01-01

Zeolite-X was synthesized from bottom ash power plant waste using fusion method on air atmosphere. The fused product dissolved in demineralized water and aluminate solution was added to adjust the SiO2/Al2O3 molar ratio gel prior hydrothermal process. The synthesis results were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Fourier Transform Infrared (FTIR). The results showed that the zeolite-X has a high crystallinity with octahedral particle. The pure-form zeolite-X then was characterized and tested for H2 gas adsorption by gravimetric method to determine the H2 gas adsorption capacity of zeolite-X from bottom ash and it was compared to synthetic zeolite-X.

Tribological characterization of TiN coatings prepared by magnetron sputtering

NASA Astrophysics Data System (ADS)

Makwana, Nishant S.; Chauhan, Kamlesh V.; Sonera, Akshay L.; Chauhan, Dharmesh B.; Dave, Divyeshkumar P.; Rawal, Sushant K.

2018-05-01

Titanium nitride (TiN) coating deposited on aluminium and brass pin substrates using RF reactive magnetron sputtering. The structural properties and surface morphology were characterized by X-ray diffraction (XRD), atomic force microscope (AFM) and field emission scanning electron microscope (FE-SEM). There was formation of (101) Ti2N, (110) TiN2 and (102) TiN0.30 peaks at 3.5Pa, 2Pa and 1.25Pa sputtering pressure respectively. The tribological properties of coating were inspected using pin on disc tribometer equipment. It was observed that TiN coated aluminium and brass pins demonstrated improved wear resistance than uncoated aluminium and brass pins.

X-ray microscopy using reflection targets based on SEM with tungsten filament

NASA Astrophysics Data System (ADS)

Liu, Junbiao; Ma, Yutian; Zhao, Weixia; Niu, Geng; Chu, Mingzhang; Yin, Bohua; Han, Li; Liu, Baodong

2016-10-01

X-ray MicroandNano imaging is developed based on the conventional x-ray tomography, it can not only provide nondestructive testing with higher resolution measurement, but also be used to examine the material or the structure with low atomic number and low density. The source with micro-focal spot size is one of the key components of x-ray MicroandNano imaging. The focused electron beam from SEM bombarding the metal target can generate x-ray with ultra-small size. It is convenient to set up x-ray microscopy based on SEM for laboratory use. This paper describes a new x-ray microscopy using reflection targets based on FEI Quanta600 SEM with tungsten filament. The flat panel detector is placed outside of the vacuum chamber with 300μm thickness Be-window to isolate vacuum from the air. A stage with 3 DOFs is added to adjust the positions of the target, the SEM's sample stage is used to move sample. And the shape of target is designed as cone with 60° half cone angle to get the maximum x-ray dosage. The attenuation coefficient of Bewindow for x-ray is about 25%. Finally, the line pair card is used to evaluate the resolution and the result shows that the resolution of the system can receive less than 750nm, when the acceleration voltage is 30keV, the beam current is 160nA, the SEM working distance is 5mm and the acquisition time of the detector is 60s.

Deuterium permeation of amorphous alumina coating on 316L prepared by MOCVD

NASA Astrophysics Data System (ADS)

Li, Shuai; He, Di; Liu, Xiaopeng; Wang, Shumao; Jiang, Lijun

2012-01-01

The deuterium permeation behavior of the alumina coating on 316L stainless steel prepared by metal organic chemical vapor deposition (MOCVD) was investigated. The alumina coating was also characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that the as-prepared coating consisted of amorphous alumina. This alumina coating had a dense, crack-free and homogeneous morphology. Although the alumina coating was amorphous, effective suppression of deuterium permeation was demonstrated. The deuterium permeability of the alumina coating was 51-60 times less than that of the 316L stainless steel and 153-335 times less than that of the referred low activation martensitic steels at 860-960 K.

Structural and photoluminescence properties of Ni doped CdS nanoparticles synthesis by sol gel method

NASA Astrophysics Data System (ADS)

Mahdi, Hadeel Salih; Parveen, Azra; Azam, Ameer

2018-05-01

Ni doped CdS nanoparticles have been successfully synthesized by sol-gel method. Nickel nitrate, cadmium nitrate, sodium sulfide has been used as precursors for the preparation of these Ni-doped CdS nanoparticles. The structural properties were studied by X-ray diffraction analysis. Surface morphology and the composition of the samples were studied by scanning electron microscope (SEM). The X-ray diffraction results revealed that the Ni-doped CdS nanoparticles were in hexagonal structure. The crystallite size was determined from Debye-Scherer equation and showed that the particle size increases with the doping of Ni. Optical absorption spectra of Ni doped CdS also was studied by Photoluminescence spectroscopy in the range of 200-600 nm.

Band edge movement and structural modifications in transition metal doped TiO2 nanocrystals for the application of DSSC

NASA Astrophysics Data System (ADS)

Patle, L. B.; Huse, V. R.; Chaudhari, A. L.

2017-10-01

Nanocrystalline undoped and transition metal ion doped (TM:Cu2+, Mn2+ and Fe3+) TiO2 nanoparticles, with 1 mol% were synthesized by a simple and cost effective modified co-precipitation method at room temperature and were successfully used as photoanode for dye sensitized solar cell (DSSC). The effect of transition metal ions into TiO2 nano crystalline powder has been systematically investigated using x-ray diffraction (XRD), UV-Vis spectroscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive x-ray spectroscopy (EDX). The results of XRD confirm nanocrystalline anatase tetragonal structure of prepared undoped and TM doped TiO2 semiconductor. The influence of doping on band edge movement has been estimated using UV-visible spectroscopy. The SEM results indicate that microscopic effect of doping on morphology of the TiO2. The peaks of EDX signify incorporation of transition metal cations into TiO2 lattice. The effect of doping on flat band potential was estimated using interpolation on Mott-Schottky plot. The performances of DSSCs of undoped and doped TiO2 photoelectrodes were investigated under light illumination. In comparison with undoped and (Cu2+, Fe3+) doped TiO2 photoanodes we found that incorporation of Mn2+ into TiO2 exhibits improvement in photoconversion efficiency (η). There is increase in photoconversion efficiency of DSSCs with Mn2+ doped TiO2 by 6% as compared to that of undoped TiO2 photoanode.

Imaging properties and its improvements of scanning/imaging x-ray microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeuchi, Akihisa, E-mail: take@spring8.or.jp; Uesugi, Kentaro; Suzuki, Yoshio

A scanning / imaging X-ray microscope (SIXM) system has been developed at SPring-8. The SIXM consists of a scanning X-ray microscope with a one-dimensional (1D) X-ray focusing device and an imaging (full-field) X-ray microscope with a 1D X-ray objective. The motivation of the SIXM system is to realize a quantitative and highly-sensitive multimodal 3D X-ray tomography by taking advantages of both the scanning X-ray microscope using multi-pixel detector and the imaging X-ray microscope. Data acquisition process of a 2D image is completely different between in the horizontal direction and in the vertical direction; a 1D signal is obtained with themore » linear-scanning while the other dimensional signal is obtained with the imaging optics. Such condition have caused a serious problem on the imaging properties that the imaging quality in the vertical direction has been much worse than that in the horizontal direction. In this paper, two approaches to solve this problem will be presented. One is introducing a Fourier transform method for phase retrieval from one phase derivative image, and the other to develop and employ a 1D diffuser to produce an asymmetrical coherent illumination.« less

Design, Fabrication and Testing of Multilayer Coated X-Ray Optics for the Water Window Imaging X-Ray Microscope

NASA Technical Reports Server (NTRS)

Spencer, Dwight C.

1996-01-01

Hoover et. al. built and tested two imaging Schwarzschild multilayer microscopes. These instruments were constructed as prototypes for the "Water Window Imaging X-Ray Microscope," which is a doubly reflecting, multilayer x-ray microscope configured to operate within the "water window." The "water window" is the narrow region of the x-ray spectrum between the K absorption edges of oxygen (lamda = 23.3 Angstroms) and of carbon (lamda = 43.62 Angstroms), where water is relatively highly transmissive and carbon is highly absorptive. This property of these materials, thus permits the use of high resolution multilayer x-ray microscopes for producing high contrast images of carbon-based structures within the aqueous physiological environments of living cells. We report the design, fabrication and testing of multilayer optics that operate in this regime.

Synthesis of Mn doped ZnS nanocrystals: Crystallographic and morphological study

NASA Astrophysics Data System (ADS)

Shaikh, Azharuddin Z.; Shirsath, Narendra B.; Sonawane, Prabhakar S.

2018-05-01

The influence of doping concentration on the physical properties of ZnS nanocrystals synthesized using coprecipitation method at room temperature is reported in this paper. In particular, we have studied the structural properties of Zn1-xMnxS where (x=0.01, 0.03, 0.05) by X-ray diffraction. X-ray peak broadening analysis used to calculate the crystalline sizes, lattice parameters, number of unit cell per particle and volume of unit cell. Crystalline ZnS with a cubic structure is confirmed by XRD results. The grain size of pure and Mn doped samples were found in the range of 7nm to 9nm. All the physical parameters of cubic ZnS nanocrystals were calculated are similar with standard values. The scanning electron microscope (SEM) which revealed that the synthesized nanocrystals are well-crystalline and possessing cubic phase.

Fabrication of large area plasmonic nanoparticle grating structure on silver halide based transmission electron microscope film and its application as a surface enhanced Raman spectroscopy substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Singh, M. N.

The plasmonic responses of silver nanoparticle grating structures of different periods made on silver halide based electron microscope film are investigated. Raster scan of the conventional scanning electron microscope (SEM) is used to carry out electron beam lithography for fabricating the plasmonic nanoparticle grating (PNG) structures. Morphological characterization of the PNG structures, carried out by the SEM and the atomic force microscope, indicates that the depth of the groove decreases with a decrease in the grating period. Elemental characterization performed by the energy dispersive spectroscopy and the x-ray diffraction shows the presence of nanoparticles of silver in the PNG grating.more » The optical characterization of the gratings shows that the localized surface plasmon resonance peak shifts from 366 to 378 nm and broadens with a decrease in grating period from 10 to 2.5 μm. The surface enhanced Raman spectroscopy of the Rhodamine-6G dye coated PNG structure shows the maximum enhancement by two orders of magnitude in comparison to the randomly distributed silver nanoparticles having similar size and shape as the PNG structure.« less

Surface phenomena of hydroxyapatite film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants.

PubMed

Kim, Eun-Ju; Jeong, Yong-Hoon; Choe, Han-Cheol

2013-03-01

In this study, surface phenomena of hydroxyapatite (HA) film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants have been investigated by electron beam physical vapor deposition (EB-PVD), field emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), potentiostat and contact angle. The microstructure of Ti-29Nb-xZr alloys exhibited equiaxed structure and alpha" phase decreased, whereas beta phase increased as Zr content increased. The increment of Zr contents in HA coated nanotubular Ti-29Nb-xZr alloys showed good corrosion potential in 0.9% NaCI solution. The wettability of HA coated nanotubular surface was higher than that of non-coated samples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bekar, Kursat B.; Miller, Thomas Martin; Patton, Bruce W.

This report is the final deliverable of a 3 year project whose purpose was to investigate the possibility of using simulations of X-ray spectra generated inside a scanning electron microscope (SEM) as a means to perform quantitative analysis of the sample imaged in the SEM via an inverse analysis methodology. Using the nine point Technology Readiness Levels (TRL) typically used by the US Department of Defense (DOD) and the National Aeronautics and Space Administration (NASA), this concept is now at a TRL of 3. In other words, this work has proven the feasibility of this concept and is ready tomore » be further investigated to address some of the issues highlighted by this initial proof of concept.« less

Electrodeposition of Zn-doped α-nickel hydroxide with flower-like nanostructure for supercapacitors

NASA Astrophysics Data System (ADS)

You, Zheng; Shen, Kui; Wu, Zhicheng; Wang, Xiaofeng; Kong, Xianghua

2012-08-01

Zn-doped α-nickel hydroxide materials with flower-like nanostructures are synthesized by electrochemical deposition method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (SEM) and electrochemical measurements. XRD spectra indicate nickel hydroxide doped with Zn is α-Ni(OH)2 with excellent crystallization. The SEM observation shows that the formation of Zn-doped Ni(OH)2 includes two steps: a honeycomb-like film forms on the substrate first, then flower-like particles forms on the films. The nickel hydroxide doped with 5% Zn can maintain a maximum specific capacitance of 860 F g-1, suggesting its potential application in electrochemical capacitors.

Fabrication of high-k dielectric Calcium Copper Titanate (CCTO) target by solid state route

NASA Astrophysics Data System (ADS)

Tripathy, N.; Das, K. C.; Ghosh, S. P.; Bose, G.; Kar, J. P.

2016-02-01

CaCu3Ti4O12 (CCTO) ceramic pellet of 10mm diameter has been synthesized by adopting solid state route. The structural and morphological characterization of the ceramics sample was carried out by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. XRD pattern revealed the CCTO phase formation, where as SEM micrograph shows the sample consisting of well defined grain and grain boundaries. The room temperature dielectric constant of the sample was found to be ∼ 5000 at 1kHz. After successful preparation of CCTO pellet, a 2 inch diameter CCTO sputtering target is also fabricated in order to deposit CCTO thin films for microelectronic applications.

A study on magneto-optic properties of CoxMg1-xFe2O4 nanoferrofluids

NASA Astrophysics Data System (ADS)

Karthick, R.; Ramachandran, K.; Srinivasan, R.

2018-04-01

Nanoparticles of CoxMg1-xFe2O4 (x = 0.1, 0.5, 0.9) were synthesized using chemical co-precipitation method. Characterization by X-ray diffraction technique confirmed the formation of cubic crystalline structure and the crystallite size of the samples obtained using Debye-Scherrer approximation were found to increase with increasing cobalt substitution. Surface morphology and the Chemical composition of the samples were visualized using scanning electron microscope (SEM) with energy dispersive analysis of X-rays (EDAX). Room temperature magnetic parameters of the nanoparticles by vibrating sample magnetometer (VSM) revealed the magnetic properties such as Saturation magnetization (Ms), Remanent magnetization (Mr) and Coercive field (Hc) found to increase with increasing cobalt substitution. Faraday rotation measurements on CoxMg1-xFe2O4 ferrofluids exhibited increase in rotation with cobalt substitution. Further, there is an increase in Faraday rotation with increasing magnetic field for all the samples.

Reflection soft X-ray microscope and method

DOEpatents

Suckewer, Szymon; Skinner, Charles H.; Rosser, Roy

1993-01-01

A reflection soft X-ray microscope is provided by generating soft X-ray beams, condensing the X-ray beams to strike a surface of an object at a predetermined angle, and focusing the X-ray beams reflected from the surface onto a detector, for recording an image of the surface or near surface features of the object under observation.

Reflection soft X-ray microscope and method

DOEpatents

Suckewer, S.; Skinner, C.H.; Rosser, R.

1993-01-05

A reflection soft X-ray microscope is provided by generating soft X-ray beams, condensing the X-ray beams to strike a surface of an object at a predetermined angle, and focusing the X-ray beams reflected from the surface onto a detector, for recording an image of the surface or near surface features of the object under observation.

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens.

PubMed

Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong

2013-11-01

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10(-2) Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens

NASA Astrophysics Data System (ADS)

Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong

2013-11-01

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10-2 Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Guided self-assembly of nanostructured titanium oxide.

PubMed

Wang, Baoxiang; Rozynek, Zbigniew; Fossum, Jon Otto; Knudsen, Kenneth D; Yu, Yingda

2012-02-24

A series of nanostructured titanium oxide particles were synthesized by a simple wet chemical method and characterized by means of small-angle x-ray scattering (SAXS)/wide-angle x-ray scattering (WAXS), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal analysis, and rheometry. Tetrabutyl titanate (TBT) and ethylene glycol (EG) can be combined to form either TiO(x) nanowires or smooth nanorods, and the molar ratio of TBT:EG determines which of these is obtained. Therefore, TiO(x) nanorods with a highly rough surface can be obtained by hydrolysis of TBT with the addition of cetyl-trimethyl-ammonium bromide (CTAB) as surfactant in an EG solution. Furthermore, TiO(x) nanorods with two sharp ends can be obtained by hydrolysis of TBT with the addition of salt (LiCl) in an EG solution. The AFM results show that the TiO(x) nanorods with rough surfaces are formed by the self-assembly of TiO(x) nanospheres. The electrorheological (ER) effect was investigated using a suspension of titanium oxide nanowires or nanorods dispersed in silicone oil. Oil suspensions of titanium oxide nanowires or nanorods exhibit a dramatic reorganization when submitted to a strong DC electric field and the particles aggregate to form chain-like structures along the direction of applied electric field. Two-dimensional SAXS images from chains of anisotropically shaped particles exhibit a marked asymmetry in the SAXS patterns, reflecting the preferential self-assembly of the particles in the field. The suspension of rough TiO(x) nanorods shows stronger ER properties than that of the other nanostructured TiO(x) particles. We find that the particle surface roughness plays an important role in modification of the dielectric properties and in the enhancement of the ER effect.

The X-ray microscopy beamline UE46-PGM2 at BESSY

NASA Astrophysics Data System (ADS)

Follath, R.; Schmidt, J. S.; Weigand, M.; Fauth, K.

2010-06-01

The Max Planck Institute for Metal Physics in Stuttgart and the Helmholtz Center Berlin operate a soft X-ray microscopy beamline at the storage ring BESSY II. A collimated PGM serves as monochromator for a scanning X-ray microscope and a full field X-ray microscope at the helical undulator UE46. The selection between both instruments is accomplished via two switchable focusing mirrors. The scanning microscope (SM) is based on the ALS STXM microscope and fabricated by the ACCEL company. The full field microscope (FFM) is currently in operation at the U41-SGM beamline and will be relocated to its final location this year.

Compact scanning transmission x-ray microscope at the photon factory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeichi, Yasuo, E-mail: yasuo.takeichi@kek.jp; Inami, Nobuhito; Ono, Kanta

We report the design and performance of a compact scanning transmission X-ray microscope developed at the Photon Factory. Piezo-driven linear stages are used as coarse stages of the microscope to realize excellent compactness, mobility, and vibrational and thermal stability. An X-ray beam with an intensity of ∼10{sup 7} photons/s was focused to a diameter of ∼40 nm at the sample. At the soft X-ray undulator beamline used with the microscope, a wide range of photon energies (250–1600 eV) is available. The microscope has been used to research energy materials and in environmental sciences.

[In vitro study with techniques of imaging of the composition of urinary calculi].

PubMed

Tellez Martínez-Fornés, M; Burgos Revilla, F J; Sáez Garrido, J C; Soria Descalzo, J; Barbero González, J; Sánchez Corral, J; Minaya Minaya, A; Vallejo Herrador, J

1997-02-01

Pre-treatment knowledge of the lithiasic composition can be useful to design the most appropriate therapeutic scheme for each kind of stone. The relationship between the stone's densitometry information provided by the different imaging techniques, conventional radiology (RX), computerized axial tomography (CAT) and dual energy radiographic densitometry (DO) is analyzed, as well as the elemental composition determined by the microanalysis of fragments obtained post-lithotrity using a scanning electronic microscope (SEM) associated to X-ray dispersion energy (XDE). 60 stones, 12 for each pure composition selected (calcium oxalate mono and dihydro, phosphocarbonate, magnesium ammonium phosphate and uric acid), were studied with XR, CAT and DO and were later subjected to lithofragmentation in vitro. Fragments analysis was carried out post-lithotrity with SEM associated to XDE. The X-ray does not allow to establish the composition of some calculi. CAT quantifies the mineral contents of the oxalocalcic and infective calculi and differentiates the uric acid from the other compositions because the mean density values are under 500 Hounsfield Units. DO evaluates the lithiasic content in phosphocarbonate salts which are structurally similar to bone hydroxyapatite.

Acetone sensors based on microsheet-assembled hierarchical Fe2O3 with different Fe3+ concentrations

NASA Astrophysics Data System (ADS)

Wang, Han; Yan, Lei; Li, Shuo; Li, Yu; Liu, Li; Du, Liting; Duan, Haojie; Cheng, Yali

2018-02-01

Several different morphologies of microsheet-assembled Fe2O3 have been fabricated by hydrothermal method using diverse concentrations of Fe3+ precursor solutions (0.025, 0.020, 0.015, 0.010 mol/L Fe3+). The as-synthesized materials have been characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), and energy-dispersive X-ray spectrometry (EDS). The SEM images reflect that the morphologies of as-synthesized materials are affected by the concentrations of Fe3+ in precursor solutions. The less concentration of Fe3+, the more porous of Fe2O3 microflowers, and thinner of slices distributed on the surface. Furthermore, gas sensors based on these Fe2O3 microflowers manufactured and tested to various common gases. The optimum response value to 100 ppm acetone is 52 at the working temperature of 220 °C. Meanwhile, the Fe2O3 microflower sensors possess ultrafast response-recovery speed, which are 8 and 19 s, respectively. The possible sensing mechanism was mainly attributed to the high surface area, three-dimensional porous structure.

Synthesis of TiO2 Nanoparticle and its phase Transition

NASA Astrophysics Data System (ADS)

Mangrola, M. H.; Joshi, V. G.; Parmar, B. H.

2011-12-01

Here we report the synthesis of titanium dioxide (TiO2) nanoparticles and study of its phase transition from anataze to rutile. Titanium dioxide (TiO2) nanoparticles have been prepared by hydrolysis of Titanium isopropoxide an aqueous solution with constant value of pH 2 and peptizing the resultant suspension gel(white-Blue) and calcinate gel at different temperature. Structures of synthetic samples of TiO2 have been examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The anatase-rutile transition has been a popular topic due to its interest to scientific and engineering fields. . Here we have seen that the 100 °C calcinate powder consist of anatase fine crystalline phase with a particle size 14 to 15 nm. The prepared TiO2 nanoparticles have uniform size and morphology, and the phase transformation kinetics of obtained material was studied by interpretation of the X-ray diffraction patterns peaks. The phase transform occurred from anatase to rutile at calcinate temperature up to 600 °C. A very fine network texture made from uniform nanoparticles was revealed by scanning electron microscopy (SEM) analyses.

Mobility of rare earth elements in mine drainage: Influence of iron oxides, carbonates, and phosphates.

PubMed

Edahbi, Mohamed; Plante, Benoît; Benzaazoua, Mostafa; Ward, Matthew; Pelletier, Mia

2018-05-01

The geochemical behavior of rare earth elements (REE) was investigated using weathering cells. The influence of sorption and precipitation on dissolved REE mobility and fractionation is evaluated using synthetic iron-oxides, carbonates, and phosphates. Sorption cell tests are conducted on the main lithologies of the expected waste rocks from the Montviel deposit. The sorbed materials are characterized using a scanning electron microscope (SEM) equipped with a microanalysis system (energy dispersive spectroscopy EDS) (SEM-EDS), X-ray diffraction (XRD), and X-ray absorption near edge structure (XANES) in order to understand the effect of the synthetic minerals on REE mobility. The results confirm that sorption and precipitation control the mobility and fractionation of REE. The main sorbent phases are the carbonates, phosphates (present as accessory minerals in the Montviel waste rocks), and iron oxides (main secondary minerals generated upon weathering of the Montviel lithologies). The XANES results show that REE are present as trivalent species after weathering. Thermodynamic equilibrium calculations results using Visual Minteq suggest that REE could precipitate as secondary phosphates (REEPO 4 ). Copyright © 2018 Elsevier Ltd. All rights reserved.

Photoelectrochemical Performance of TiO2/Ti Electrode for Organic Compounds

NASA Astrophysics Data System (ADS)

Maulidiyah, M.; Wijawan, I. B. P.; Wibowo, D.; Aladin, A.; Hamzah, B.; Nurdin, M.

2018-05-01

Photoelectrochemical performance of TiO2/Ti electrode was investigated by using organic compounds. The TiO2/Ti electrode was prepared by anodic oxidation at a potential bias of 25 V for 4 h then calcined for 450 °C to obtain the anatase polymorph. Subsequently, it was characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX). The XRD pattern showed that TiO2 has anatase phase as confirmed by 2θ peaks at 37.93° 63.00°, and 83.00°. Using SEM-EDX data the TiO2 layer was formed on Ti plate with the composition of Ti (4.5 keV) and O (0.5 keV) elements. Furthermore, the photoelectrochemical sensing on the three organic compounds (ascorbic acid, glucose, and titan yellow) with the electrolyte addition showed that the linearity of TiO2/Ti electrode were 0.937, 0.968, and 0.938, meanwhile without the electrolyte were 0.998, 0.989, and 0.923, respectively.

A new method of nanocrystalline nickel powder formation by magnetron sputtering on the water-soluble substrates

NASA Astrophysics Data System (ADS)

Tučkutė, S.; Urbonavičius, M.; Lelis, M.; Maiorov, M.; Díaz Ordaz, J. R.; Milčius, D.

2018-01-01

Due to the accurate and relatively easy control magnetron sputtering is an attractive technique for the synthesis of metallic particles. This work describes a new method of nickel powder production by depositing nickel on the surface of sodium chloride particles which were used as the template and are soluble in water. Ni powder with flake-like structure was obtained after washing Ni coated salt particles in ultrasonic cleaner. Salt particles and nickel powder were characterized using scanning electron microscope (SEM), energy-dispersive x-ray spectrometer, XRD and X-ray photoelectron spectroscopy (XPS) techniques. SEM images showed that thickness of the received Ni particles varied in the nanoscale and depended on the magnetron deposition time but did not depend on the size of salt particles. On the other hand initial size of the salt particles was successfully employed a measure to control lateral dimensions of Ni powder. XRD and XPS analysis results revealed that Ni particles had metallic core and oxidized shell which was a cause of the slightly deteriorated magnetic properties.

Nano-sized ZnO powders prepared by co-precipitation method with various pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purwaningsih, S. Y., E-mail: sriyanisaputri@gmail.com; Pratapa, S.; Triwikantoro,

2016-04-19

In this work, nano-sized ZnO powders have been synthesized by the co-precipitation method with Zn(CH3COOH)2.2H2O, HCl, and NH3.H2O as raw materials in various pH ranging from 8 to 10. The purity, microstructure, chemical group analysis, morphology of the prepared ZnO powders were studied by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), energy dispersive X-ray spectrometry (EDX), and scanning electron microscope (SEM), respectively. Rietveld refinement of XRD data showed that ZnO crystallizes in the wurtzite structure with high purity. The obtained powders were nano-sized particles with the average crystallite size about 17.9 ± 2.1 nm synthesized with pH of 9.5, atmore » 85°C, and stirring time of 6 h. The SEM results have visualied the morphology of ZnO nanoparticles with spherical-like shape. The effect of processing conditions on morphology of ZnO was also discussed.« less

Combined PIXE and X-ray SEM studies on time-resolved deposits of welding shop aerosols

NASA Astrophysics Data System (ADS)

Barfoot, K. M.; Mitchell, I. V.; Verheyen, F.; Babeliowsky, T.

1981-03-01

Time-resolved deposits of welding shop air particulates have been obtained using a streak sampling system. PIXE analysis of these deposits, using 2 MeV protons, typically revealed the presence of a large number of elements, with many in the range Z = 11-30. Strong variations, up to three orders of magnitude, in the concentrations of several elements such as Al, Si and Fe as well as Zn, Na, K and Ca were found. The 2 h sampling resolution normally used was found to be insufficient to follow the short pollution episodes that regularly occur in a welding shop environment and so sampling with a 20 min resolution was used. The variation of elemental concentrations for different sampling times together with information on the physical nature of these air particulates, determined with a scanning electron microscope (SEM) and Si(Li) X-ray detector attachment, are presented. This type of information together with that obtained from the PIXE analysis is of importance in industrial hygiene studies. The need to make corrections for partial filter clogging, based on air-flow rate monitoring, is discussed.

PVP capped CdS nanoparticles for UV-LED applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sivaram, H.; Selvakumar, D.; Jayavel, R., E-mail: rjvel@annauniv.edu

Polyvinlypyrrolidone (PVP) capped cadmium sulphide (CdS) nanoparticles are synthesized by wet chemical method. The powder X-ray diffraction (XRD) result indicates that the nanoparticles are crystallized in cubic phase. The optical properties are characterized by UV-Vis absorption. The morphology of CdS nanoparticles are studied using Scanning electron microscope (SEM). The thermal behavior of the as prepared nanoparticles has been examined by Thermo gravimetric analysis (TGA). The optical absorption study of pvp capped CdS reveal a red shift confirms the UV-LED applications.

Ilmenite exsolution schemes in Apollo-17 high-Ti basalts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaniman, D.; Heiken, G.; Muhich, T.

1990-01-01

Combined electron microprobe and scanning electron microscope (SEM) x-ray image analyses are used to obtain semiquantitative data on the relations between ilmenite grains and their exsolved chromite and rutile. Comparisons of these data for ilmenites in four Apollo-17 high-Ti basalts with a database of electron microprobe analyses from the literature indicates that Cr expulsion from ilmenite can be as important as Fe{sup 2+} reduction in causing subsolidus exsolution of chromite and rutile from ilmenite. 12 refs., 4 figs., 5 tabs.

DEVELOPMENT OF LiCo0.90Mg0.05Al0.05O2 THIN FILMS BY PULSED LASER DEPOSITION TECHNIQUE

NASA Astrophysics Data System (ADS)

Vasanthi, R.; Ruthmangani, I.; Manoravi, P.; Joseph, M.; Kesavamoorthy, R.; Sundar, C.; Selladurai, S.

LiCo0.90Mg0.05Al0.05O2 bulk powders are synthesized using combustion process and made into a thin film by depositing on silicon wafer using a pulsed laser ablation technique. A comparative study by SEM (Scanning Electron Microscope) XRD (X-ray diffraction), Infrared spectroscopy and Raman Spectroscopy is performed on both bulk and PLD thin films.

Flake like V{sub 2}O{sub 5} nanoparticles for ethanol sensing at room temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chitra, M.; Uthayarani, K.; Rajasekaran, N.

2016-05-23

The versatile redox property of vanadium oxide explores it in various applications like catalysis, electrochromism, electrochemistry, energy storage, sensors, microelectronics, batteries etc., In this present work, vanadium oxide was prepared via hydrothermal route followed by calcination. The structural and lattice parameters were analysed from the powder X-ray diffraction (XRD) pattern. The morphology and the composition of the sample were obtained from Field emission Scanning electron microscopic (FeSEM) and Energy Dispersive X-ray (EDAX) Spectrometric analysis respectively. The sensitivity, response – recovery time of the sample towards ethanol (0 ppm – 300 ppm) sensing at room temperature was measured and the present investigation onmore » vanadium oxide nanoparticles over the flakes shows better sensitivity (30%) at room temperature.« less

Structural and optical properties of Ni-doped CdS thin films prepared by chemical bath deposition method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Premarani, R.; Saravanakumar, S., E-mail: sarophy84@gmail.com; Chandramohan, R.

2015-06-24

The structural and optical behavior of undoped Cadmiun Sulphide (CdS) and Ni-doped CdS thinfilms prepared by Chemical Bath Deposition (CBD) technique is reported. The crystallite sizes of the thinfilms have been characterized by X-ray diffraction pattern (XRD). The particle sizes increase with the increase of Ni content in the CdS thinfilms. Scanning Electron Microscope (SEM) results indicated that CdS thinfilms is made up of aggregate of spherical-like particles. The composition was estimated by Energy Dispersive Analysis of X-ray (EDX) and reported. Spectroscopic studies revealed considerable improvement in transmission and the band gap of the films changes with addition of Nimore » dopant that is associated with variation in crystallite sizes in the nano regime.« less

Micro-Raman and FT-IR spectroscopic studies of ceramic shards excavated from ancient Stratonikeia city at Eskihisar village in West-South Turkey

NASA Astrophysics Data System (ADS)

Bahçeli, Semiha; Güleç, Gamze; Erdoğan, Hasan; Söğüt, Bilal

2016-02-01

In this study, micro-Raman and Fourier transformed infrared (FT-IR) spectroscopies, X-ray diffraction (XRD) and scanning electron microscope with energy dispersive X-ray (SEM-EDX) were used to characterize the mineralogical structures of pigments of four ceramic fragments in which one of them belongs to Hellenistic period (1st - IVth century BC) and other three ceramic shards belong to Early Rome (IVth century BC- 1st century AD) excavated from Stratonikeia ancient city. In the results of investigations on these four ceramic fragments, the various phases were identified: quartz, kaolinite, albit (or Na-feldspar), calcite, anastase, hematite and magnetite. Furthermore, the obtained findings indicate that firing temperature is about 800-850 °C for all the shards.

Physicochemical characterisation of natural K-clinoptilolite and heavy-metal forms from Gördes (Manisa, western Turkey)

NASA Astrophysics Data System (ADS)

Ünaldı, Tevfik; Mızrak, İbrahim; Kadir, Selahattin

2013-12-01

Physicochemical characterisation of natural K-clinoptilolite and heavy-metal (Ag+, Cd2+, Cr3+ and Co3+) forms was accomplished through ion exchange by batch, X-ray diffractometric (XRD), X-ray fluorescence (XRF), infrared-spectral (FT-IR), differential thermal analysis-thermal gravimetric (DTA-TG) and scanning-electron microscopic (SEM) methods. Increasing the normality in the cases of heavy-metal forms resulted in decrease in crystallinity and increases in unit-cell volume, rate of ion exchange, and percentage of ion selectivity. In this study, the order of ion-selectivity percentages (rather than ion selectivity) of heavy-metal forms was determined to be Ag+ > Cd2+ > Cr3+ > Co3+. This finding is consistent with the results of worldwide research on the order of ion selectivity in modified clinoptilolite.

A facile and green preparation of reduced graphene oxide using Eucalyptus leaf extract

NASA Astrophysics Data System (ADS)

Li, Chengyang; Zhuang, Zechao; Jin, Xiaoying; Chen, Zuliang

2017-11-01

In this paper, a green and facile synthesis of reduced graphene oxide (GO) by Eucalyptus leaf extract (EL-RGO) was investigated, which was characterized with ultraviolet-visible spectroscopy (UV), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and Thermal gravimetric analysis (TG). Eucalyptus leaf extract also play both reducing and capping stabilizing agents prepared EL-RGO as shown a good stability and electrochemical properties. This approach could provide an alternative method to prepare EL-RGO in large-scale production. Moreover, the good electrochemical property and biocompatibility can be used in various applications. In addition, the merit of this study is that both the oxidized products and the reducing agents are environmental friendly by green reduction.

Influences of Co doping on the structural and optical properties of ZnO nanostructured

NASA Astrophysics Data System (ADS)

Majeed Khan, M. A.; Wasi Khan, M.; Alhoshan, Mansour; Alsalhi, M. S.; Aldwayyan, A. S.

2010-07-01

Pure and Co-doped ZnO nanostructured samples have been synthesized by a chemical route. We have studied the structural and optical properties of the samples by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), field-emission transmission electron microscope (FETEM), energy-dispersive X-ray (EDX) analysis and UV-VIS spectroscopy. The XRD patterns show that all the samples are hexagonal wurtzite structures. Changes in crystallite size due to mechanical activation were also determined from X-ray measurements. These results were correlated with changes in particle size followed by SEM and TEM. The average crystallite sizes obtained from XRD were between 20 to 25 nm. The TEM images showed the average particle size of undoped ZnO nanostructure was about 20 nm whereas the smallest average grain size at 3% Co was about 15 nm. Optical parameters such as absorption coefficient ( α), energy band gap ( E g ), the refractive index ( n), and dielectric constants ( σ) have been determined using different methods.

Structure and optical properties of TiO2 thin films deposited by ALD method

NASA Astrophysics Data System (ADS)

Szindler, Marek; Szindler, Magdalena M.; Boryło, Paulina; Jung, Tymoteusz

2017-12-01

This paper presents the results of study on titanium dioxide thin films prepared by atomic layer deposition method on a silicon substrate. The changes of surface morphology have been observed in topographic images performed with the atomic force microscope (AFM) and scanning electron microscope (SEM). Obtained roughness parameters have been calculated with XEI Park Systems software. Qualitative studies of chemical composition were also performed using the energy dispersive spectrometer (EDS). The structure of titanium dioxide was investigated by X-ray crystallography. A variety of crystalline TiO2 was also confirmed by using the Raman spectrometer. The optical reflection spectra have been measured with UV-Vis spectrophotometry.

Scanning electron microscopic and X-ray micro analysis on tooth enamel exposed to alkaline agents.

PubMed

Taubee, Fabian; Steiniger, Frank; Nietzsche, Sandor; Norén, Jörgen G

2010-01-01

The background of this study comprises two clinical cases, where patients exposed to aerosols of an alkaline and surface active cleaning agent developed loss of enamel substance on their teeth, further resulting in loss of teeth and partially destroyed soft tissues. The alkaline cleaning agent consisted of potassium hydroxide and various surfactants. The purpose of this study was to investigate possible changes in morphology and composition in human teeth enamel exposed to alkaline solutions, by means of X-ray micro analysis (XRMA), FTIR-spectroscopic analyses and scanning electron microscopy (SEM). Extracted premolars, exposed to potassium hydroxide solutions and alkaline cleaning solution,were analyzed by means of XRMA and SEM. Enamel powder, exposed to cleaning solution, was analyzed by means of FTIR. The SEM analysis revealed an increased porosity of the enamel surface and partially loss of enamel substance after exposure to alkaline solutions. The XRMA analyses revealed a decrease in carbon concentration while phosphorous and calcium showed no marked changes. The FTIR analyses showed no significant changes in peak heights or peak positions for phosphate, carbonate or hydroxide. It was concluded that human teeth enamel exposed to alkaline solutions showed loss of organic substance, marked pores in enamel surface and loss of substance in the enamel surface.

Correlative fractography: combining scanning electron microscopy and light microscopes for qualitative and quantitative analysis of fracture surfaces.

PubMed

Hein, Luis Rogerio de Oliveira; de Oliveira, José Alberto; de Campos, Kamila Amato

2013-04-01

Correlative fractography is a new expression proposed here to describe a new method for the association between scanning electron microscopy (SEM) and light microscopy (LM) for the qualitative and quantitative analysis of fracture surfaces. This article presents a new method involving the fusion of one elevation map obtained by extended depth from focus reconstruction from LM with exactly the same area by SEM and associated techniques, as X-ray mapping. The true topographic information is perfectly associated to local fracture mechanisms with this new technique, presented here as an alternative to stereo-pair reconstruction for the investigation of fractured components. The great advantage of this technique resides in the possibility of combining any imaging methods associated with LM and SEM for the same observed field from fracture surface.

Development of x-ray laminography under an x-ray microscopic condition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa

2011-07-15

An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatialmore » resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.« less

X ray microscope assembly and alignment support and advanced x ray microscope design and analysis

NASA Technical Reports Server (NTRS)

Shealy, David L.

1991-01-01

Considerable efforts have been devoted recently to the design, analysis, fabrication, and testing of spherical Schwarzschild microscopes for soft x ray application in microscopy and projection lithography. The spherical Schwarzschild microscope consists of two concentric spherical mirrors configured such that the third order spherical aberration and coma are zero. Since multilayers are used on the mirror substrates for x ray applications, it is desirable to have only two reflecting surfaces in a microscope. In order to reduce microscope aberrations and increase the field of view, generalized mirror surface profiles have been considered in this investigation. Based on incoherent and sine wave modulation transfer function (MTF) calculations, the object plane resolution of a microscope has been analyzed as a function of the object height and numerical aperture (NA) of the primary for several spherical Schwarzschild, conic, and aspherical head reflecting two mirror microscope configurations.

Optoelectronic and Electrochemical Properties of Vanadium Pentoxide Nanowires Synthesized by Vapor-Solid Process

PubMed Central

Pan, Ko-Ying; Wei, Da-Hua

2016-01-01

Substantial synthetic vanadium pentoxide (V2O5) nanowires were successfully produced by a vapor-solid (VS) method of thermal evaporation without using precursors as nucleation sites for single crystalline V2O5 nanowires with a (110) growth plane. The micromorphology and microstructure of V2O5 nanowires were analyzed by scanning electron microscope (SEM), energy-dispersive X-ray spectroscope (EDS), transmission electron microscope (TEM) and X-ray diffraction (XRD). The spiral growth mechanism of V2O5 nanowires in the VS process is proved by a TEM image. The photo-luminescence (PL) spectrum of V2O5 nanowires shows intrinsic (410 nm and 560 nm) and defect-related (710 nm) emissions, which are ascribable to the bound of inter-band transitions (V 3d conduction band to O 2p valence band). The electrical resistivity could be evaluated as 64.62 Ω·cm via four-point probe method. The potential differences between oxidation peak and reduction peak are 0.861 V and 0.470 V for the first and 10th cycle, respectively. PMID:28335268

Effect of heat input on microstructure, wear and friction behavior of (wt.-%) 50FeCrC-20FeW-30FeB coating on AISI 1020 produced by using PTA welding.

PubMed

Özel, Cihan; Gürgenç, Turan

2018-01-01

In this study, AISI 1020 steel surface was coated in different heat inputs with (wt.-%) 50FeCrC-20FeW-30FeB powder mixture by using plasma transferred arc (PTA) welding method. The microstructure of the coated samples were investigated by using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDS). The hardness was measured with micro hardness test device. The dry sliding wear and friction coefficient properties were determined using a block-on-disk type wear test device. Wear tests were performed at 19.62 N, 39.24 N, 58.86 N load and the sliding distance of 900 m. The results were shown that different microstructures formed due to the heat input change. The highest average micro hardness value was measured at 1217 HV on sample coated with low heat input. It was determined that the wear resistance decreased with increasing heat input.

ZnO/TiO2 nanocomposite rods synthesized by microwave-assisted method for humidity sensor application

NASA Astrophysics Data System (ADS)

Ashok, CH.; Venkateswara Rao, K.

2014-12-01

The nanocomposite rods shows well known properties compared with nano structured materials for various applications like light-emitting diodes, electron field emitters, solar cells, optoelectronics, sensors, transparent conductors and fabrication of nano devices. Present paper investigates the properties of ZnO/TiO2 nanocomposite rods. The bi component of ZnO/TiO2 nanocomposite rods was synthesized by microwave-assisted method which is very simple, rapid and uniform in heating. The frequency of microwaves 2.45 GHz was used and temperature maintained 180 °C. Zinc acetate and titanium isopropoxide precursors were used in the preparation. The obtained ZnO/TiO2 nanocomposite rods were annealed at 500 °C and 600 °C. ZnO/TiO2 nanocomposite rods have been characterized by X-ray Diffraction (XRD) for average crystallite size and phase of the composite material, Particle Size Analyser (PSA) for average particle size, Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) for morphology study, Energy Dispersive X-ray Spectrometry (EDX) for elemental analysis, and Thermal Gravimetric and Differential Thermal Analysis (TG-DTA) for thermal property.

Time-dependent gel to gel transformation of a peptide based supramolecular gelator.

PubMed

Baral, Abhishek; Basak, Shibaji; Basu, Kingshuk; Dehsorkhi, Ashkan; Hamley, Ian W; Banerjee, Arindam

2015-06-28

A dipeptide with a long fatty acid chain at its N-terminus gives hydrogels in phosphate buffer in the pH range 7.0-8.5. The hydrogel with a gelator concentration of 0.45% (w/v) at pH 7.46 (physiological pH) provides a very good platform to study dynamic changes within a supramolecular framework as it exhibits remarkable change in its appearance with time. Interestingly, the first formed transparent hydrogel gradually transforms into a turbid gel within 2 days. These two forms of the hydrogel have been thoroughly investigated by using small angle X-ray scattering (SAXS), powder X-ray diffraction (PXRD), field emission scanning electron microscopic (FE-SEM) and high-resolution transmission electron microscopic (HR-TEM) imaging, FT-IR and rheometric analyses. The SAXS and low angle PXRD studies substantiate different packing arrangements for the gelator molecules for these two different gel states (the freshly prepared and the aged hydrogel). Moreover, rheological studies of these two gels reveal that the aged gel is stiffer than the freshly prepared gel.

Effect of heat input on microstructure, wear and friction behavior of (wt.-%) 50FeCrC-20FeW-30FeB coating on AISI 1020 produced by using PTA welding

PubMed Central

Gürgenç, Turan

2018-01-01

In this study, AISI 1020 steel surface was coated in different heat inputs with (wt.-%) 50FeCrC-20FeW-30FeB powder mixture by using plasma transferred arc (PTA) welding method. The microstructure of the coated samples were investigated by using optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDS). The hardness was measured with micro hardness test device. The dry sliding wear and friction coefficient properties were determined using a block-on-disk type wear test device. Wear tests were performed at 19.62 N, 39.24 N, 58.86 N load and the sliding distance of 900 m. The results were shown that different microstructures formed due to the heat input change. The highest average micro hardness value was measured at 1217 HV on sample coated with low heat input. It was determined that the wear resistance decreased with increasing heat input. PMID:29324875

Trace Element Mapping of a Biological Specimen by a Full-Field X-ray Fluorescence Imaging Microscope with a Wolter Mirror

NASA Astrophysics Data System (ADS)

Hoshino, Masato; Yamada, Norimitsu; Ishino, Toyoaki; Namiki, Takashi; Watanabe, Norio; Aoki, Sadao

2007-01-01

A full-field X-ray fluorescence imaging microscope with a Wolter mirror was applied to the element mapping of alfalfa seeds. The X-ray fluorescence microscope was built at the Photon Factory BL3C2 (KEK). X-ray fluorescence images of several growing stages of the alfalfa seeds were obtained. X-ray fluorescence energy spectra were measured with either a solid state detector or a CCD photon counting method. The element distributions of iron and zinc which were included in the seeds were obtained using a photon counting method.

Quantitative Electron-Excited X-Ray Microanalysis of Borides, Carbides, Nitrides, Oxides, and Fluorides with Scanning Electron Microscopy/Silicon Drift Detector Energy-Dispersive Spectrometry (SEM/SDD-EDS) and NIST DTSA-II.

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2015-10-01

A scanning electron microscope with a silicon drift detector energy-dispersive X-ray spectrometer (SEM/SDD-EDS) was used to analyze materials containing the low atomic number elements B, C, N, O, and F achieving a high degree of accuracy. Nearly all results fell well within an uncertainty envelope of ±5% relative (where relative uncertainty (%)=[(measured-ideal)/ideal]×100%). Quantification was performed with the standards-based "k-ratio" method with matrix corrections calculated based on the Pouchou and Pichoir expression for the ionization depth distribution function, as implemented in the NIST DTSA-II EDS software platform. The analytical strategy that was followed involved collection of high count (>2.5 million counts from 100 eV to the incident beam energy) spectra measured with a conservative input count rate that restricted the deadtime to ~10% to minimize coincidence effects. Standards employed included pure elements and simple compounds. A 10 keV beam was employed to excite the K- and L-shell X-rays of intermediate and high atomic number elements with excitation energies above 3 keV, e.g., the Fe K-family, while a 5 keV beam was used for analyses of elements with excitation energies below 3 keV, e.g., the Mo L-family.

Synthesis and microstructural studies of annealed Cu(2)O/Cu(x)S bilayer as transparent electrode material for photovoltaic and energy storage devices.

PubMed

Taleatu, B A; Arbab, E A A; Omotoso, E; Mola, G T

2014-10-01

Cu2 O thin film and a transparent bilayer have been fabricated by electrodeposition method. The growths were obtained in potentiostatic mode with gradual degradation of anodic current. X-ray diffraction (XRD) study showed that the bilayer is polycrystalline and it possesses mixture of different crystallite phases of copper oxides. Surface morphology of the films was investigated by scanning electron microscopy (SEM). The SEM images revealed that the films were uniformly distributed and the starting material (Cu2 O) had cubical structure. Grains agglomeration and crystallinity were enhanced by annealing. Optical studies indicated that all the samples have direct allowed transition. Energy band gap of the bilayer film was reduced by annealing treatment thus corroborating quantum confinement upshot. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Imaging Schwarzschild multilayer X-ray microscope

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Baker, Phillip C.; Shealy, David L.; Core, David B.; Walker, Arthur B. C., Jr.; Barbee, Troy W., Jr.; Kerstetter, Ted

1993-01-01

We have designed, analyzed, fabricated, and tested Schwarzschild multilayer X-ray microscopes. These instruments use flow-polished Zerodur mirror substrates which have been coated with multilayers optimized for maximum reflectivity at normal incidence at 135 A. They are being developed as prototypes for the Water Window Imaging X-Ray Microscope. Ultrasmooth mirror sets of hemlite grade sapphire have been fabricated and they are now being coated with multilayers to reflect soft X-rays at 38 A, within the biologically important 'water window'. In this paper, we discuss the fabrication of the microscope optics and structural components as well as the mounting of the optics and assembly of the microscopes. We also describe the optical alignment, interferometric and visible light testing of the microscopes, present interferometrically measured performance data, and provide the first results of optical imaging tests.

Development of Thin Films as Potential Structural Cathodes to Enable Multifunctional Energy-Storage Structural Composite Batteries for the U.S. Army’s Future Force

DTIC Science & Technology

2011-09-01

glancing angle X - ray diffraction (GAXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemical...Emission SEM FWHM full width at half maximum GAXRD glancing angle X - ray diffraction H3COCH2CH2OH 2-methoxyethanol LiMn2O4 lithium manganese oxide...were characterized by scanning electron microscopy (SEM), X - ray diffraction (XRD), and atomic force microscopy (AFM). In addition,

Design of an imaging microscope for soft X-ray applications

NASA Astrophysics Data System (ADS)

Hoover, Richard B.; Shealy, David L.; Gabardi, David R.; Walker, Arthur B. C., Jr.; Lindblom, Joakim F.

1988-01-01

An imaging soft X-ray microscope with a spatial resolution of 0.1 micron and normal incidence multilayer optics is discussed. The microscope has a Schwarzschild configuration, which consists of two concentric spherical mirrors with radii of curvature which minimize third-order spherical aberration, coma, and astigmatism. The performance of the Stanford/MSFC Cassegrain X-ray telescope and its relevance to the present microscope are addressed. A ray tracing analysis of the optical system indicates that diffraction-limited performance can be expected for an object height of 0.2 mm.

Chemical characterization of surface precipitates in La0.7Sr0.3Co0.2Fe0.8O3-δ as cathode material for solid oxide fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Yang; Nikiforov, Alexey Y.; Kaspar, Tiffany C.

2016-11-01

In this study, a strontium doped lanthanum cobalt ferrite thin film with 30% Sr on A-site, denoted as La0.7Sr0.3Co0.2Fe0.8O3-δ or LSCF-7328, was investigated before and after annealing at 800 °C under CO2 containing atmosphere for 9 hours. The formation of secondary phases on surface of post-annealed LSCF-7328 has been observed using atomic force microscope (AFM) and scanning electron microscope (SEM). The extent of Sr segregation at the film surface was observed using the synchrotron-based total reflection X-ray fluorescence (TXRF) technique. The bonding environment of the secondary phases formed on the surface was investigated by synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES).more » Transmission electron microscope (TEM) and related spectroscopy techniques were used for microstructural and quantitative elemental analyses of the secondary phases on surface. These studies revealed that the secondary phases on surface consisted of SrO covered with a capping layer of SrCO3. The formation of Co-rich phases has also been observed on the surface of post-annealed LSCF-7328.« less

Morphology studies of hydrophobic silica on filter surface prepared via spray technique

NASA Astrophysics Data System (ADS)

Shahfiq Zulkifli, Nazrul; Zaini Yunos, Muhamad; Ahmad, Azlinnorazia; Harun, Zawati; Akhair, Siti Hajar Mohd; Adibah Raja Ahmad, Raja; Hafeez Azhar, Faiz; Rashid, Abdul Qaiyyum Abd; Ismail, Al Emran

2017-08-01

This study investigated the effect of the hydrophobic surface treatment effect of air filter performance by using silica aerogel powder as an additive by using spray coating techniques. The membrane characterization tests were carried out on a filter prepared from different additive concentration. Studies on the cross-section and the distribution of particles on the membrane were carried out using a scanning electron microscope (SEM), and the surface morphology was investigated by x-ray spectroscopy (EDS). The results are shown by SEM and EDS that the microstructure filter, especially in the upper layer and sub-layer has been changed. The results also show an increase of hydrophobicity due to the increased quantity of silica aerogel powder.

Preparation of a novel breviscapine-loaded halloysite nanotubes complex for controlled release of breviscapine

NASA Astrophysics Data System (ADS)

Gao, Min; Lu, Liqian; Wang, Xiaoyue; Lin, Houke; Zhou, Qingsong

2017-11-01

For sustain the release rate and prolong half-life of breviscapine in vivo, the breviscapine-loaded halloysite nanotubes complex was prepared. The breviscapine was encapsulated into halloysite nanotubes (HNTs) using a vacuum process. The complex were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), transmission electron microscope (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy(FT-IR). The formation of breviscapine-loaded HNTs complex was proved by the test results of SEM, DSC, TEM and IR analysise. The results confirmed that breviscapine was successfully loaded in the halloysite nanotubes. Additionally, the in vitro drug release of breviscapine from breviscapine-loaded HNTs complex was investigated, the result indicated this complex has apparent sustained-release effect.

[Preparation of sodium alginate-nanohydroxyapatite composite material for bone repair and its biocompatibility].

PubMed

Wang, Yanmei; He, Jiacai; Li, Quanli; Shen, Jijia

2014-02-01

To prepare sodium alginate-nanohydroxyapatite composite material and to explore its feasibility as a bone repair material. Sodium alginate-nanohydroxyapatite composite material was prepared using chemical cross-linking and freeze-drying technology. The composite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) and its porosity was measured by liquid displacement method. The fifth passage of bone marrow stromal stem cells (BMSCs) were incubated on the composite material and then growth was observed by inverted microscope and SEM. BMSCs were cultured with liquid extracts of the material, methyl thiazolyl tetrazolium (MTT) assay was used to calculate the relative growth rate (RGR) on 1, 3, 5 d and to evaluate the cytotoxicity. Fresh dog blood was added into the liquid extracts to conduct hemolysis test, the spectrophotometer was used to determine the optical density (OD) and to calculate the hemolysis rate. Sodium alginate-nanohydroxyapatite composite material displayed porosity, the porous pore rate was (88.6 +/- 4.5)%. BMSCs showed full stretching and vigorous growth under inverted microscope and SEM. BMSCs cultured with liquid extracts of the material had good activities. The toxicity of composite material was graded as 1. Hemolysis test results showed that the hemolysis rate of the composite material was 1.28%, thus meeting the requirement of medical biomaterials. The composite material fabricated in this study has high porosity and good biocompatibility.

Eco-friendly preparation of large-sized graphene via short-circuit discharge of lithium primary battery.

PubMed

Kang, Shaohong; Yu, Tao; Liu, Tingting; Guan, Shiyou

2018-02-15

We proposed a large-sized graphene preparation method by short-circuit discharge of the lithium-graphite primary battery for the first time. LiC x is obtained through lithium ions intercalation into graphite cathode in the above primary battery. Graphene was acquired by chemical reaction between LiC x and stripper agents with dispersion under sonication conditions. The gained graphene is characterized by Raman spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Atomic force microscope (AFM) and Scanning electron microscopy (SEM). The results indicate that the as-prepared graphene has a large size and few defects, and it is monolayer or less than three layers. The quality of graphene is significant improved compared to the reported electrochemical methods. The yield of graphene can reach 8.76% when the ratio of the H 2 O and NMP is 3:7. This method provides a potential solution for the recycling of waste lithium ion batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

Green synthesis and spectral characterization of silver nanoparticles from Lakshmi tulasi (Ocimum sanctum) leaf extract

NASA Astrophysics Data System (ADS)

Subba Rao, Y.; Kotakadi, Venkata S.; Prasad, T. N. V. K. V.; Reddy, A. V.; Sai Gopal, D. V. R.

2013-02-01

A simple method for the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of Lakshmi tulasi (Ocimum sanctum) leaf as a reducing and stabilizing agent. AgNPs were rapidly synthesized using aqueous extract of tulasi leaf with AgNO3 solution within 15 min. The green synthesized AgNPs were characterized using physic-chemical techniques viz., UV-Vis, X-ray diffraction (XRD), scanning electron microscope (SEM) coupled with X-ray energy dispersive spectroscopy (EDX) and Fourier transform-infrared spectroscopy (FT-IR). Characterization data reveals that the particles were crystalline in nature and triangle shaped with an average size of 42 nm. The zeta potential of AgNPs were found to be -55.0 mV. This large negative zeta potential value indicates repulsion among AgNPs and their dispersion stability.

Electrochemical and XPS study of LiFePO4 cathode nanocomposite with PPy/PEG conductive network

NASA Astrophysics Data System (ADS)

Fedorková, A.; Oriňáková, R.; Oriňák, A.; Kupková, M.; Wiemhöfer, H.-D.; Audinot, J. N.; Guillot, J.

2012-08-01

High performance PPy/PEG-LiFePO4 nanocomposites as cathode materials were synthesized by solvothermal method and simple chemical oxidative polymerization of pyrrole (Py) monomer on the surface of LiFePO4 particles. The samples were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectrometry (XPS) and charge-discharge tests. PPyPEG hybrid layers decrease particle to particle contact resistance while the impedance measurements confirmed that the coating of PPy-PEG significantly decreases the charge transfer resistance of the electrode material. The initial discharge capacities of this sample at C/5 and 1C are 150 and 128 mAh/g, respectively. The results show that PPy/PEGLiFePO4 composites are more effective than bare LiFePO4 as cathode material.

Photocatalytic Degradation Effect of μ-Dielectric Barrier Discharge Plasma Treated Titanium Dioxide Nanoparticles on Environmental Contaminant.

PubMed

Seo, Hyeon Jin; Hwang, Ki-Hwan; Na, Young Hoon; Boo, Jin-Hyo

2018-09-01

This study focused on the photocatalytic degradation effect of the μ-dielectric barrier discharge (μ-DBD) plasma treated titanium dioxide (TiO2) nanoparticles on environmental contaminant such as formaldehyde. TiO2 nanoparticles were treated by a μ-DBD plasma source with nitrogen gas. We analyzed the degradation of formaldehyde with the plasma treated TiO2 nanoparticles by UV-visible spectrophotometer (UV-VIS), and demonstrated that the photocatalytic activity of the μ-DBD plasma-treated TiO2 nanoparticles showed significantly high catalytic efficiency rather than without plasma treated TiO2 nanoparticles. Field emission scanning electron microscopes (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and water contact angle analyzer were used to measure the effects of photocatalytic degradation for the plasma treated TiO2 nanoparticles.

Structural and optical properties of WTe2 single crystals synthesized by DVT technique

NASA Astrophysics Data System (ADS)

Dixit, Vijay; Vyas, Chirag; Pathak, V. M.; Soalanki, G. K.; Patel, K. D.

2018-05-01

Layered transition metal di-chalcogenide (LTMDCs) crystals have attracted much attention due to their potential in optoelectronic device applications recently due to realization of their monolayer based structures. In the present investigation we report growth of WTe2 single crystals by direct vapor transport (DVT) technique. These crystals are then characterized by energy dispersive analysis of x-rays (EDAX) to study stoichiometric composition after growth. The structural properties are studied by x-ray diffraction (XRD) and selected area electron diffraction (SAED) is used to confirm orthorhombic structure of grown WTe2 crystal. Surface morphological properties of the crystals are also studied by scanning electron microscope (SEM). The optical properties of the grown crystals are studied by UV-Visible spectroscopy which gives direct band gap of 1.44 eV for grown WTe2 single crystals.

Ellipsoidal and parabolic glass capillaries as condensers for x-ray microscopes.

PubMed

Zeng, Xianghui; Duewer, Fred; Feser, Michael; Huang, Carson; Lyon, Alan; Tkachuk, Andrei; Yun, Wenbing

2008-05-01

Single-bounce ellipsoidal and paraboloidal glass capillary focusing optics have been fabricated for use as condenser lenses for both synchrotron and tabletop x-ray microscopes in the x-ray energy range of 2.5-18 keV. The condenser numerical apertures (NAs) of these devices are designed to match the NA of x-ray zone plate objectives, which gives them a great advantage over zone plate condensers in laboratory microscopes. The fabricated condensers have slope errors as low as 20 murad rms. These capillaries provide a uniform hollow-cone illumination with almost full focusing efficiency, which is much higher than what is available with zone plate condensers. Sub-50 nm resolution at 8 keV x-ray energy was achieved by utilizing this high-efficiency condenser in a laboratory microscope based on a rotating anode generator.

Synthesis and characterization of intercalated polyaniline-clay nanocomposite using supercritical CO2

NASA Astrophysics Data System (ADS)

Abdelraheem, A.; El-Shazly, A. H.; Elkady, M. F.

2018-05-01

Lately, supercritical CO2 (SCCO2) have been getting great interest. It can be used in numerous applications because it is environmentally friendly, safe, comparatively low cost, and nonflammable. One of its applications is being a solvent in the synthesis of polymeric-clay nanocomposite. In this paper, intercalated polyaniline-clay nanocomposite (PANC) was prepared using SCCO2. The intercalation structure of polyaniline chains between clay layers was verified by various characterization techniques. Scanning electron microscope and transmission electron microscope (SEM-TEM) were used to show the morphology of the synthesized nanocomposite. The molecular structure of PANC nanocomposite was confirmed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The BET surface area and the conductivity of the nanocomposite were determined.

A facile thermal decomposition route to synthesise CoFe2O4 nanostructures

NASA Astrophysics Data System (ADS)

Kalpanadevi, K.; Sinduja, C. R.; Manimekalai, R.

2014-01-01

The synthesis of CoFe2O4 nanoparticles has been achieved by a simple thermal decomposition method from an inorganic precursor, cobalt ferrous cinnamate hydrazinate (CoFe2(cin)3(N2H4)3) which was obtained by a novel precipitation method from the corresponding metal salts, cinnamic acid and hydrazine hydrate. The precursor was characterized by hydrazine and metal analyses, infrared spectral analysis and thermo gravimetric analysis. Under appropriate annealing, CoFe2(cin)3(N2H4)3 yielded CoFe2O4 nanoparticles, which were characterized for their size and structure using X-Ray diffraction (XRD), high resolution transmission electron microscopic (HRTEM), selected area electron diffraction (SAED) and scanning electron microscopic (SEM) techniques.

Synthesis, characterization, in vitro anti-proliferative and hemolytic activity of hydroxyapatite

NASA Astrophysics Data System (ADS)

Palanivelu, R.; Ruban Kumar, A.

2014-06-01

Hydroxyapatite (Ca10(PO4)6(OH)2, HAP) nanoparticles are widely used in several biomedical applications due to its compositional similarities to bone mineral, excellent biocompatibility and bioactivity, osteoconductivity. In this present investigation, HAP nanoparticles synthesized by precipitation technique using calcium nitrate and di-ammonium phosphate. The crystalline nature and the functional group analysis are confirmed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Fourier transform Raman spectroscopy (FT-Raman) respectively. The morphological observations are ascertained from field emission electron scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). In vitro anti-proliferative and hemolytic activities are carried out on the synthesized HAP samples and the studies reveals that HAP have mild activity against erythrocytes.

Effect of reduced graphene oxide-carbon nanotubes hybrid nanofillers in mechanical properties of polymer nanocomposites

NASA Astrophysics Data System (ADS)

Sa, Kadambinee; Mahakul, Prakash C.; Subramanyam, B. V. R. S.; Raiguru, Jagatpati; Das, Sonali; Alam, Injamul; Mahanandia, Pitamber

2018-03-01

Graphene and carbon nanotubes (CNTs) have tremendous interest as reinforcing fillers due to their excellent physical properties. However, their reinforcing effect in polymer matrix is limited due to agglomeration of graphene and CNTs within the polymer matrix. Mechanical properties by the admixture of reduced graphene oxide (rGO) and CNTs in Poly (methyl methacrylate) (PMMA) prepared by solution mixing method has been investigated. The prepared samples are characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy. The hybrid composite shows improvement in the mechanical properties compared to rGO/PMMA and MWCNTs/PMMA composites due to better interaction between rGO-MWCNTs and polymer matrix.

Effects of Laser Shock Processing on Morphologies and Mechanical Properties of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion

PubMed Central

Zhang, Lei; Lu, Jin-Zhong; Zhang, Yong-Kang; Ma, Hai-Le; Luo, Kai-Yu; Dai, Feng-Ze

2017-01-01

Effects of laser shock processing (LSP) on the cavitation erosion resistance of laser weldments were investigated by optical microscope (OM), scanning electron microscope (SEM) observations, roughness tester, micro hardness tester, and X-ray diffraction (XRD) technology. The morphological microstructures were characterized. Cumulative mass loss, incubation period, erosion rate, and damaged surface areas were monitored during cavitation erosion. Surface roughness, micro-hardness, and residual stress were measured in different zones. Results showed that LSP could improve the damage of morphological microstructures and mechanical properties after cavitation erosion. The compressive residual stresses were generated during the process of LSP, which was an effective guarantee for the improvement of the above mentioned properties. PMID:28772652

Laboratory-size three-dimensional water-window x-ray microscope with Wolter type I mirror optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohsuka, Shinji; The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu-cho, Nishi-ku, Hamamatsu-City, 431-1202; Ohba, Akira

2016-01-28

We constructed a laboratory-size three-dimensional water-window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques. It consists of an electron-impact x-ray source emitting oxygen Kα x-rays, Wolter type I grazing incidence mirror optics, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit better than 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm-scale three-dimensional fine structures were resolved.

PtyNAMi: ptychographic nano-analytical microscope at PETRA III: interferometrically tracking positions for 3D x-ray scanning microscopy using a ball-lens retroreflector

NASA Astrophysics Data System (ADS)

Schroer, Christian G.; Seyrich, Martin; Kahnt, Maik; Botta, Stephan; Döhrmann, Ralph; Falkenberg, Gerald; Garrevoet, Jan; Lyubomirskiy, Mikhail; Scholz, Maria; Schropp, Andreas; Wittwer, Felix

2017-09-01

In recent years, ptychography has revolutionized x-ray microscopy in that it is able to overcome the diffraction limit of x-ray optics, pushing the spatial resolution limit down to a few nanometers. However, due to the weak interaction of x rays with matter, the detection of small features inside a sample requires a high coherent fluence on the sample, a high degree of mechanical stability, and a low background signal from the x-ray microscope. The x-ray scanning microscope PtyNAMi at PETRA III is designed for high-spatial-resolution 3D imaging with high sensitivity. The design concept is presented with a special focus on real-time metrology of the sample position during tomographic scanning microscopy.

Influence of the divalent and trivalent ions substitution on the structural and magnetic properties of Mg0.5-xCdxCo0.5Cr0.04TbyFe1.96-yO4 ferrites prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Mustafa, Ghulam; Islam, M. U.; Zhang, Wenli; Anwar, Abdul Waheed; Jamil, Yasir; Murtaza, Ghulam; Ali, Ihsan; Hussain, Mudassar; Ali, Akbar; Ahmad, Mukhtar

2015-08-01

A series of the divalent and trivalent co-substituted Mg0.5-xCdxCo0.5Cr0.04TbyFe1.96-yO4 spinel ferrite systems (where x=0-0.5 in steps of 0.1 and y=0.00-0.10 in steps 0.02) are synthesized by sol-gel auto combustion method. The product materials were characterized by the thermo gravimetric analysis and differential scanning calorimetry (TGA/DSC), Fourier transform infrared spectra (FTIR), nitrogen adsorption (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The X-ray diffraction patterns and Fourier transform infrared spectroscopy confirm spinel nanocrystalline phase. The crystallite size is determined by Scherer's formula from 36.6 to 69.4 nm. The X-ray density is found in the range of 5.09-6.43 (g/cm3). The morphological features are studied using scanning electron microscope and AFM. Saturation magnetization (Ms) and remanence (Mr) magnetization extracted from M-H loops exhibit the decreasing trends 21.4-16 emu/g and 9.1-6.3 emu/g, respectively. A significant decrease in the intrinsic parameters is observed in the prepared samples due to the weakening of the A-B interaction as iron enters into the tetrahedral A-site. The coercivity lies in the range of 300-869 Oe as a function of co-substitution contents. The coercivity of the sample with x=0.1, y=0.02 was found maximum i.e. 869 Oe. The obtained results suggest that the investigated materials may be potential candidates for high density recording media applications.

Eight-channel Kirkpatrick-Baez microscope for multiframe x-ray imaging diagnostics in laser plasma experiments.

PubMed

Yi, Shengzhen; Zhang, Zhe; Huang, Qiushi; Zhang, Zhong; Mu, Baozhong; Wang, Zhanshan; Fang, Zhiheng; Wang, Wei; Fu, Sizu

2016-10-01

Because grazing-incidence Kirkpatrick-Baez (KB) microscopes have better resolution and collection efficiency than pinhole cameras, they have been widely used for x-ray imaging diagnostics of laser inertial confinement fusion. The assembly and adjustment of a multichannel KB microscope must meet stringent requirements for image resolution and reproducible alignment. In the present study, an eight-channel KB microscope was developed for diagnostics by imaging self-emission x-rays with a framing camera at the Shenguang-II Update (SGII-Update) laser facility. A consistent object field of view is ensured in the eight channels using an assembly method based on conical reference cones, which also allow the intervals between the eight images to be tuned to couple with the microstrips of the x-ray framing camera. The eight-channel KB microscope was adjusted via real-time x-ray imaging experiments in the laboratory. This paper describes the details of the eight-channel KB microscope, its optical and multilayer design, the assembly and alignment methods, and results of imaging in the laboratory and at the SGII-Update.

Crystallography of Magnetite Plaquettes and their Significance as Asymmetric Catalysts for the Synthesis of Chiral Organics in Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Chan, Q. H. S.; Zolensky, M. E.

2015-01-01

We have previously observed the magnetite plaquettes in carbonaceous chondrites using scanning electron microscope (SEM) imaging, examined the crystal orientation of the polished surfaces of magnetite plaquettes in CI Orgueil using electron backscattered diffraction (EBSD) analysis, and concluded that these magnetite plaquettes are likely naturally asymmetric materials. In this study, we expanded our EBSD observation to other magnetite plaquettes in Orgueil, and further examined the internal structure of these remarkable crystals with the use of X-ray computed microtomography.

Effect of preparation conditions on the nanostructure of hydroxyapatite and brushite phases

NASA Astrophysics Data System (ADS)

Mansour, S. F.; El-dek, S. I.; Ahmed, M. A.; Abd-Elwahab, S. M.; Ahmed, M. K.

2016-10-01

Hydroxyapatite (HAP) and dicalcium phosphate dihydrate (brushite) nanoparticles were prepared by co-precipitation method. The obtained products were characterized by X-ray powder diffraction (XRD), Fourier transformation infra-red spectroscopy (FTIR) and thermo-gravimetric analysis (TGA). Scanning electron microscopy (SEM) and transmission electron microscope (TEM) were used to investigate the morphology of the powdered samples as well as their microstructure, respectively. Brushite samples were obtained in a spherical shape, while hydroxyapatite was formed in a needle and rice shape depending on the pH value.

Water window imaging x ray microscope

NASA Technical Reports Server (NTRS)

Hoover, Richard B. (Inventor)

1992-01-01

A high resolution x ray microscope for imaging microscopic structures within biological specimens has an optical system including a highly polished primary and secondary mirror coated with identical multilayer coatings, the mirrors acting at normal incidence. The coatings have a high reflectivity in the narrow wave bandpass between 23.3 and 43.7 angstroms and have low reflectivity outside of this range. The primary mirror has a spherical concave surface and the secondary mirror has a spherical convex surface. The radii of the mirrors are concentric about a common center of curvature on the optical axis of the microscope extending from the object focal plane to the image focal plane. The primary mirror has an annular configuration with a central aperture and the secondary mirror is positioned between the primary mirror and the center of curvature for reflecting radiation through the aperture to a detector. An x ray filter is mounted at the stage end of the microscope, and film sensitive to x rays in the desired band width is mounted in a camera at the image plane of the optical system. The microscope is mounted within a vacuum chamber for minimizing the absorption of x rays in air from a source through the microscope.

Probing Stress States in Silicon Nanowires During Electrochemical Lithiation Using In Situ Synchrotron X-Ray Microdiffraction

DOE PAGES

Ali, Imran; Tippabhotla, Sasi Kumar; Radchenko, Ihor; ...

2018-04-04

Silicon is considered as a promising anode material for the next-generation lithium-ion battery (LIB) due to its high capacity at nanoscale. However, silicon expands up to 300% during lithiation, which induces high stresses and leads to fractures. To design silicon nanostructures that could minimize fracture, it is important to understand and characterize stress states in the silicon nanostructures during lithiation. Synchrotron X-ray microdiffraction has proven to be effective in revealing insights of mechanical stress and other mechanics considerations in small-scale crystalline structures used in many important technological applications, such as microelectronics, nanotechnology, and energy systems. In the present study, anmore » in situ synchrotron X-ray microdiffraction experiment was conducted to elucidate the mechanical stress states during the first electrochemical cycle of lithiation in single-crystalline silicon nanowires (SiNWs) in an LIB test cell. Morphological changes in the SiNWs at different levels of lithiation were also studied using scanning electron microscope (SEM). It was found from SEM observation that lithiation commenced predominantly at the top surface of SiNWs followed by further progression toward the bottom of the SiNWs gradually. The hydrostatic stress of the crystalline core of the SiNWs at different levels of electrochemical lithiation was determined using the in situ synchrotron X-ray microdiffraction technique. We found that the crystalline core of the SiNWs became highly compressive (up to -325.5 MPa) once lithiation started. In conclusion, this finding helps unravel insights about mechanical stress states in the SiNWs during the electrochemical lithiation, which could potentially pave the path toward the fracture-free design of silicon nanostructure anode materials in the next-generation LIB.« less

Probing Stress States in Silicon Nanowires During Electrochemical Lithiation Using In Situ Synchrotron X-Ray Microdiffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, Imran; Tippabhotla, Sasi Kumar; Radchenko, Ihor

Silicon is considered as a promising anode material for the next-generation lithium-ion battery (LIB) due to its high capacity at nanoscale. However, silicon expands up to 300% during lithiation, which induces high stresses and leads to fractures. To design silicon nanostructures that could minimize fracture, it is important to understand and characterize stress states in the silicon nanostructures during lithiation. Synchrotron X-ray microdiffraction has proven to be effective in revealing insights of mechanical stress and other mechanics considerations in small-scale crystalline structures used in many important technological applications, such as microelectronics, nanotechnology, and energy systems. In the present study, anmore » in situ synchrotron X-ray microdiffraction experiment was conducted to elucidate the mechanical stress states during the first electrochemical cycle of lithiation in single-crystalline silicon nanowires (SiNWs) in an LIB test cell. Morphological changes in the SiNWs at different levels of lithiation were also studied using scanning electron microscope (SEM). It was found from SEM observation that lithiation commenced predominantly at the top surface of SiNWs followed by further progression toward the bottom of the SiNWs gradually. The hydrostatic stress of the crystalline core of the SiNWs at different levels of electrochemical lithiation was determined using the in situ synchrotron X-ray microdiffraction technique. We found that the crystalline core of the SiNWs became highly compressive (up to -325.5 MPa) once lithiation started. In conclusion, this finding helps unravel insights about mechanical stress states in the SiNWs during the electrochemical lithiation, which could potentially pave the path toward the fracture-free design of silicon nanostructure anode materials in the next-generation LIB.« less

Radiation-induced changes in electrical conductivity and structure of BaPbO3 after γ-irradiation

NASA Astrophysics Data System (ADS)

Shan, Qing; Cai, Pingkun; Zhang, Xinlei; Li, Jiatong; Chu, Shengnan; Jia, Wenbao

2015-11-01

Several barium plumbate (BaPbO3) solid samples, made from PbO and BaCO3 powder by chemistry liquid-phase coprecipitation, were investigated before and after γ-irradiation. The solid samples were irradiated by a 60Co γ-irradiation source whose dose rate is about 0.7 kGy per hour. The irradiation times were 0, 72, 144, 216, 288 and 360 h. Then, the four-probe method, X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to indicate the changes in electrical conductivity and microstructure of BaPbO3 after γ-irradiation. The XRD results indicated that the content of PbO was reduced as the irradiation dose was increased and eventually vanished from the surface of samples. However, there was no new obvious substance phase found from the XRD atlas. It seems that the PbO transformed into nearly amorphous Pb5O8. The conjecture could be proved by the results of annealing experiment and SEM. The XPS results seem to show that the microstructure of BaPbO3 was slightly changed.

Wear Properties of ECAP-Processed AM80 Magnesium Alloy

NASA Astrophysics Data System (ADS)

Gopi, K. R.; Shivananda Nayaka, H.; Sahu, Sandeep

2017-07-01

AM80 magnesium alloy was subjected to equal-channel angular pressing (ECAP), and microstructural evolution was studied using scanning electron microscope (SEM). Grain size was found to decrease up to 3 µm after four passes. An increase in number of ECAP passes led to a corresponding increase in hardness of the processed samples. Unprocessed and ECAP-processed samples were subjected to wear test using pin-on-disk wear test machine to study the wear behavior. Effects of varying loads (30 and 40 N) with sliding distances (2500 and 5000 m) were studied. The results showed reduction in wear mass loss for the ECAP-processed samples in comparison with unprocessed condition. Coefficient of friction (COF) was studied for different loads, and improvement in COF values was observed for ECAP-processed samples compared to unprocessed condition. Worn surfaces were studied using SEM and energy-dispersive x-ray spectrometer, and they exhibited plastic deformation, delamination, plowing, wear debris and oxidation in the sliding direction. X-ray diffraction analysis was conducted on the worn surfaces to identify the phases. It revealed the presence of magnesium oxide and magnesium aluminum oxide which led to oxidation wear in the sliding direction. Wear mechanism was found to be abrasive and oxidation wear.

Characterization of modified PVDF membrane by gamma irradiation for non-potable water reuse.

PubMed

Lim, Seung Joo; Kim, Tak-Hyun; Shin, In Hwan

2015-01-01

Poly(vinylidene fluorine) (PVDF) membranes were grafted by gamma-ray irradiation and were sulfonated by sodium sulfite to modify the surface of the membranes. The characteristics of the modified PVDF membranes were evaluated by the data of Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscope (FE-SEM), the contact angle of the membrane surface and the water permeability. From the results of FT-IR, XPS and FE-SEM, it was shown that the modified membranes were successfully grafted by gamma-ray irradiation and were sulfonated. The content of oxygen and sulfur increased with the monomer concentration, while the content of fluorine sharply decreased. The pore size of the modified membranes decreased after gamma-ray irradiation. The contact angle and the water permeability showed that the hydrophilicity of the modified membranes played a role in determining the membrane performance. The feasibility study of the modified PVDF membranes for using non-potable water reuse were carried out using a laboratory-scale microfiltration system. Grey wastewater was used as the influent in the filtration unit, and permeate quality satisfied non-potable water reuse guidelines in the Republic of Korea.

Multimodal hard x-ray nanoprobe facility by nested Montel mirrors aimed for 40nm resolution at Taiwan Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Gung-Chian, E-mail: gcyin@nsrrc.org.tw; Chang, Shi-Hung; Chen, Bo-Yi

2016-01-28

The hard X-ray nanoprobe facility at Taiwan Photon Source (TPS) provides multimodal X-ray detections, including XRF, XAS, XEOL, projection microscope, CDI, etc. Resulting from the large numerical aperture obtained by utilizing nested Montel mirrors, the beamline with a moderate length 75 meters can conduct similar performance with those beamlines longer than 100 meters. The mirrors are symmetrically placed with a 45 degrees cut. The beamline optics is thus designed to take the advantage of the symmetry of mirrors such that a round focal spot is accomplished. The size and the divergence of the focus spot are simulated around 40 nm andmore » 6.29 mrad, respectively. The whole facility including the beamline and the stations will be operated under vacuum to preserve the photon coherence as well as to prevent the system from unnecessary environmental interference. A SEM in close cooperation with laser interferometers is equipped to precisely locate the position of the sample. This endstation is scheduled to be commissioned in the fall of 2016.« less

X-ray nanoprobe project at Taiwan Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Gung-Chian, E-mail: gcyin@nsrrc.org.tw; Chang, Shih-Hung; Chen, Bo-Yi

2016-07-27

The hard X-ray nanoprobe facility at Taiwan Photon Source (TPS) provides versatile X-ray analysis techniques, with tens of nanometer resolution, including XRF, XAS, XEOL, projection microscope, CDI, etc. Resulting from the large numerical aperture obtained by utilizing Montel KB mirrors, the beamline with a moderate length 75 meters can conduct similar performance with those beamlines longer than 100 meters. The two silica-made Montel mirrors are 45 degree cut and placed in a V-shape to eliminate the gap loss and the deformation caused by gravity. The slope error of the KB mirror pair is less than 0.04 µrad accomplished by elasticmore » emission machining (EEM) method. For the beamline, a horizontal DCM and two-stage focusing in horizontal direction is applied. For the endstation, a combination of SEM for quickly positioning the sample, a fly scanning system with laser interferometers, a precise temperature control system, and a load lock transfer system will be implemented. In this presentation, the design and construction progress of the beamline and endstation is reported. The endstation is scheduled to be in commissioning phase in 2016.« less

Electrospinning Hetero-Nanofibers In2O3/SnO2 of Homotype Heterojunction with High Gas Sensing Activity

PubMed Central

Du, Haiying; Yao, PengJun; Sun, Yanhui; Wang, Jing; Wang, Huisheng; Yu, Naisen

2017-01-01

In2O3/SnO2 composite hetero-nanofibers were synthesized by an electrospinning technique for detecting indoor volatile organic gases. The physical and chemical properties of In2O3/SnO2 hetero-nanofibers were characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), Energy Dispersive X-Ray Spectroscopy (EDX), specific surface Brunauer–Emmett–Teller (BET) and X-ray photoelectron spectroscopy (XPS). Gas sensing properties of In2O3/SnO2 composite hetero-nanofibers were measured with six kinds of indoor volatile organic gases in concentration range of 0.5~50 ppm at the operating temperature of 275 °C. The In2O3/SnO2 composite hetero-nanofibers sensor exhibited good formaldehyde sensing properties, which would be attributed to the formation of n-n homotype heterojunction in the In2O3/SnO2 composite hetero-nanofibers. Finally, the sensing mechanism of the In2O3/SnO2 composite hetero-nanofibers was analyzed based on the energy-band principle. PMID:28792433

Novel Bi/BiOBr/AgBr composite microspheres: Ion exchange synthesis and photocatalytic performance

NASA Astrophysics Data System (ADS)

Lyu, Jianchang; Li, Zhenlu; Ge, Ming

2018-06-01

Novel Bi/BiOBr/AgBr composite microspheres were prepared by a rational in situ ion exchange reaction between Bi/BiOBr microspheres and AgNO3. The characteristic of the as-obtained ternary microspheres was tested by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL). Under visible light irradiation, Bi/BiOBr/AgBr microspheres exhibited an excellent photocatalytic efficiency for rhodamine B (RhB) degradation, which was about 1.4 and 4.9 times as high as that of Bi/BiOBr and BiOBr/AgBr, demonstrating that the highest separation efficiency of charge carriers in the heterostructured Bi/BiOBr/AgBr. The photocatalytic activity of Bi/BiOBr/AgBr microspheres just exhibited a slight decrease after three consecutive cycles. The photocatalytic mechanism investigation confirmed that the superoxide radicals (O2•-) were the dominant reactive oxygen species for RhB degradation in Bi/BiOBr/AgBr suspension.

Sub-25-nm laboratory x-ray microscopy using a compound Fresnel zone plate.

PubMed

von Hofsten, Olov; Bertilson, Michael; Reinspach, Julia; Holmberg, Anders; Hertz, Hans M; Vogt, Ulrich

2009-09-01

Improving the resolution in x-ray microscopes is of high priority to enable future applications in nanoscience. However, high-resolution zone-plate optics often have low efficiency, which makes implementation in laboratory microscopes difficult. We present a laboratory x-ray microscope based on a compound zone plate. The compound zone plate utilizes multiple diffraction orders to achieve high resolution while maintaining reasonable efficiency. We analyze the illumination conditions necessary for this type of optics in order to suppress stray light and demonstrate microscopic imaging resolving 25 nm features.

Effect of the microstructure on the thermoelectric properties of polycrystalline lanthanum chalcogenides

NASA Technical Reports Server (NTRS)

Lockwood, A.; Wood, C.; Vandersande, J.; Zoltan, A.; Parker, J.; Danielson, L.; Alexander, M.; Whittenberger, D.

1987-01-01

Small amounts of second phase materials can have important effects on the thermoelectric properties of polycrystalline gamma-La(3-x)X4 (X-S, Te; X in the range of 0 to 1/3). Microscopic examination by SEM of hot pressed La(3-x)Te4 samples has revealed from 1-5 vol. pct of La2O2Te, an amount which is not detected by X-ray powder diffraction measurements. This amount of La2O2Te resulting from oxygen contamination can reduce the concentration of electrons by as much as 10 to 75 percent below the electron concentration calculated for single phase La(3-x)Te4 in the composition range of greatest interest. Small amounts of second phase materials can also lower the lattice thermal conductivity by scattering low frequency phonons. These results indicate that microstructural effects should be considered when electrical and thermal properties of polycrystalline materials are analyzed.

Design and analysis of multilayer x ray/XUV microscope

NASA Technical Reports Server (NTRS)

Shealy, David L.

1990-01-01

The design and analysis of a large number of normal incidence multilayer x ray microscopes based on the spherical mirror Schwarzschild configuration is examined. Design equations for the spherical mirror Schwarzschild microscopes are summarized and used to evaluate mirror parameters for microscopes with magnifications ranging from 2 to 50x. Ray tracing and diffraction analyses are carried out for many microscope configurations to determine image resolution as a function of system parameters. The results are summarized in three publication included herein. A preliminary study of advanced reflecting microscope configurations, where aspherics are used in place of the spherical microscope mirror elements, has indicated that the aspherical elements will improve off-axis image resolution and increase the effective field of view.

Time-Resolved, High-Resolution, X-Ray Microscopy of In-Vitro Biological and Life Science Specimens with the Aid of Laser Plasmas

DTIC Science & Technology

1994-06-30

transmissive Fresnel lens. We have made considerable effort in the last few years to explore the potential of x-ray multilayer-coated Schwarzschild x-ray...ray mirror fabrication and efficient x-ray mirror design. A 120mm diameter, NA = 0.35, 15X Schwarzschild microscope coated with Ni/C multilayer mios for...et al 2 developed a smaller, 33mm diameter, NA - 0.28, 15X Schwarzschild microscope coated with a W/C multilayer mirror for 4.4nm, in the socalled

Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO4:Dy TL material

NASA Astrophysics Data System (ADS)

Kamarudin, Nadira; Abdullah, Wan Saffiey Wan; Hamid, Muhammad Azmi Abdul; Dollah, Mohd Taufik

2014-09-01

This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO4) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 μm in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO4 with average crystallite size of 74 nm with orthorhombic crystal system. The TL behavior of produced CaSO4:Dy was studied using a TLD reader after exposure to gamma ray by Co60 source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosch, R.; Boutin, J. Y.; Le Breton, J. P.

This article describes x-ray imaging with grazing-incidence microscopes, developed for the experimental program carried out on the Ligne d'Integration Laser (LIL) facility [J. P. Le Breton et al., Inertial Fusion Sciences and Applications 2001 (Elsevier, Paris, 2002), pp. 856-862] (24 kJ, UV--0.35 nm). The design includes a large target-to-microscope (400-700 mm) distance required by the x-ray ablation issues anticipated on the Laser MegaJoule facility [P. A. Holstein et al., Laser Part. Beams 17, 403 (1999)] (1.8 MJ) which is under construction. Two eight-image Kirkpatrick-Baez microscopes [P. Kirkpatrick and A. V. Baez J. Opt. Soc. Am. 38, 766 (1948)] with differentmore » spectral wavelength ranges and with a 400 mm source-to-mirror distance image the target on a custom-built framing camera (time resolution of {approx}80 ps). The soft x-ray version microscope is sensitive below 1 keV and its spatial resolution is better than 30 {mu}m over a 2-mm-diam region. The hard x-ray version microscope has a 10 {mu}m resolution over an 800-{mu}m-diam region and is sensitive in the 1-5 keV energy range. Two other x-ray microscopes based on an association of toroidal/spherical surfaces (T/S microscopes) produce an image on a streak camera with a spatial resolution better than 30 {mu}m over a 3 mm field of view in the direction of the camera slit. Both microscopes have been designed to have, respectively, a maximum sensitivity in the 0.1-1 and 1-5 keV energy range. We present the original design of these four microscopes and their test on a dc x-ray tube in the laboratory. The diagnostics were successfully used on LIL first experiments early in 2005. Results of soft x-ray imaging of a radiative jet during conical shaped laser interaction are shown.« less

The effect of inhibitor sodium nitrate on pitting corrosion of dissimilar material weldment joint of stainless steel AISI 304 and mild steel SS 400

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hilca, B. R., E-mail: bangkithilca@yahoo.com; Triyono, E-mail: triyonomesin@uns.ac.id

This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO{sub 3}) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate contentmore » as inhibitor.« less

Preparation and antibacterial effect of silver hydroxyapatite/titania nanocomposite thin film on titanium

NASA Astrophysics Data System (ADS)

Mo, Anchun; Liao, Juan; Xu, Wei; Xian, Suqin; Li, Yubao; Bai, Shi

2008-11-01

The composite which contains Ag + and nanosized hydroxyapatite with TiO 2 was deposited onto titanium by dipping method. The morphology, chemical components and structures of the thin film were characterized by XRD, scanning electronic microscope (SEM) and energy dispersive X-ray analysis (EDX). Staphylococcus aureus and Escherichia coli were utilized to test the antibacterial effect. XRD results demonstrated that the films have characteristic diffraction peaks of pure HA. EDX results showed that the deposited films consisted of Ca, P, Ti, O and Ag, all of which distribute uniformly. With regard to the antibacterial effect, 98% of S. aureus and more than 99% of E. coli were killed after 24 h incubation and pictures of SEM showed obviously fewer cells on the surface with coating.

Graphene oxide based CdSe photocatalysts: Synthesis, characterization and comparative photocatalytic efficiency of rhodamine B and industrial dye

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Trisha; Lee, Jeong-Ho; Meng, Ze-Da

Highlights: ► CdSe–graphene is synthesized by hydrothermal method. ► Three molar solutions of CdSe were used making three different composites. ► RhB and Texbrite MST-L were used as sample dye solutions. ► Texbrite MST-L is photo degraded in visible light. ► UV-spectroscopic analysis was done to measure degradation. - Abstract: CdSe–graphene composites were prepared using simple “hydrothermal method” where the graphene surface was modified using different molar solutions of cadmium selenide (CdSe) in aqueous media. The characterization of CdSe–graphene composites were studied by X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and with transmission electron microscope (TEM).more » The catalytic activities of CdSe-composites were evaluated by degradation of rhodamine B (RhB) and commercial industrial dye “Texbrite MST-L (TXT-MST)” with fixed concentration. The degradation was observed by the decrease in the absorbance peak studied by UV spectrophotometer. The decrease in the dye concentration indicated catalytic degradation effect by CdSe–graphene composites.« less

Effects of atomic oxygen on titanium dioxide thin film

NASA Astrophysics Data System (ADS)

Shimosako, Naoki; Hara, Yukihiro; Shimazaki, Kazunori; Miyazaki, Eiji; Sakama, Hiroshi

2018-05-01

In low earth orbit (LEO), atomic oxygen (AO) has shown to cause degradation of organic materials used in spacecrafts. Similar to other metal oxides such as SiO2, Al2O3 and ITO, TiO2 has potential to protect organic materials. In this study, the anatese-type TiO2 thin films were fabricated by a sol-gel method and irradiated with AO. The properties of TiO2 were compared using mass change, scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmittance spectra and photocatalytic activity before and after AO irradiation. The results indicate that TiO2 film was hardly eroded and resistant against AO degradation. AO was shown to affects only the surface of a TiO2 film and not the bulk. Upon AO irradiation, the TiO2 films were slightly oxidized. However, these changes were very small. Photocatalytic activity of TiO2 was still maintained in spite of slight decrease upon AO irradiation, which demonstrated that TiO2 thin films are promising for elimination of contaminations outgassed from a spacecraft's materials.

Piper nigrum leaf and stem assisted green synthesis of silver nanoparticles and evaluation of its antibacterial activity against agricultural plant pathogens.

PubMed

Paulkumar, Kanniah; Gnanajobitha, Gnanadhas; Vanaja, Mahendran; Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Pandian, Kannaiyan; Annadurai, Gurusamy

2014-01-01

Utilization of biological materials in synthesis of nanoparticles is one of the hottest topics in modern nanoscience and nanotechnology. In the present investigation, the silver nanoparticles were synthesized by using the leaf and stem extract of Piper nigrum. The synthesized nanoparticle was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray analysis (EDAX), and Fourier Transform Infrared Spectroscopy (FTIR). The observation of the peak at 460 nm in the UV-vis spectra for leaf- and stem-synthesized silver nanoparticles reveals the reduction of silver metal ions into silver nanoparticles. Further, XRD analysis has been carried out to confirm the crystalline nature of the synthesized silver nanoparticles. The TEM images show that the leaf- and stem-synthesized silver nanoparticles were within the size of about 7-50 nm and 9-30 nm, respectively. The FTIR analysis was performed to identify the possible functional groups involved in the synthesis of silver nanoparticles. Further, the antibacterial activity of the green-synthesized silver nanoparticles was examined against agricultural plant pathogens. The antibacterial property of silver nanoparticles is a beneficial application in the field of agricultural nanotechnology.

High-efficiency and conveniently recyclable photo-catalysts for dye degradation based on urchin-like CuO microparticle/polymer hybrid composites

NASA Astrophysics Data System (ADS)

Liu, Xiong; Cheng, Yuming; Li, Xuefeng; Dong, Jinfeng

2018-05-01

In this work, we developed a new type of photo-catalysts composed of the urchin-like cupric oxide (CuO) microparticle and polyvinylidene fluoride (PVDF) hybrid composites by the convenient organic-inorganic hybrid strategy, which show high-efficiency and conveniently recyclable for dye degradation including methylene blue (MB), Congo red (CR), and malachite green (MG) by visible light irradiation. The micro-structural characteristics of urchin-like CuO microparticles are crucial and dominant over the photo-degrading efficiency of hybrid catalyst because of their highly exposed {0 0 2} facet and larger specific surface area. Simultaneously, the intrinsic porous framework of PVDF membrane not only remains the excellent photo-catalytic activity of urchin-like CuO microparticles but also facilitates the enrichment of dyes on the membrane, and thereby synergistically contributing to the photo-catalytic efficiency. The microstructures of both urchin-like CuO microparticles and hybrid catalysts are systematically characterized by various techniques including scanning electron microscopy (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption/desorption isotherms, which evidently support the mentioned mechanism.

Facile One-Pot Synthesis of Flower Like Cobalt Oxide Nanostructures on Nickel Plate and Its Supercapacitance Properties.

PubMed

Kandasamy, N; Venugopal, T; Kannan, K

2018-06-01

A flower like cobalt oxide nanostructured thin film (Co2O3) on Nickel (Ni) plate as have been successfully developed via alcoholic Seed Layer assisted chemical bath Deposition (SLD) process. Through the controlled alkaline electrolytes, the flower and paddles like Co2O3 nanoarchitectures were formed. The prepared thin film was characterized by X-ray diffraction (XRD), scanning electron microscope with energy dispersive X-ray (SEM and EDX), Atomic Force Microscope (AFM), Raman spectroscopy techniques. Electron micrograph reveals the flower and paddles like nanostructured Co2O3 thin film deposited on Ni plates. The electrochemical characteristics were investigated using cyclic voltammetry (CV), charge-discharge and AC impedance spectroscopy in different aqueous electrolytes such as NaOH, KOH, and LiOH. The maximum specific capacitance of 856 Fg-1 was attained with 2 M KOH electrolyte with 2 mVs-1 of the Co2O3 thin film coated Ni plate at 80 °C using SLD method. The capacitance values obtained with various electrolytes are in the order of KOH > NaOH > LiOH. The results indicate that the present method is economical and the material is ecofriendly with enhanced capacitance property.

Novel band gap-tunable K-Na co-doped graphitic carbon nitride prepared by molten salt method

NASA Astrophysics Data System (ADS)

Zhao, Jiannan; Ma, Lin; Wang, Haoying; Zhao, Yanfeng; Zhang, Jian; Hu, Shaozheng

2015-03-01

Novel band gap-tunable K-Na co-doped graphitic carbon nitride was prepared by molten salt method using melamine, KCl, and NaCl as precursor. X-ray diffraction (XRD), N2 adsorption, Scanning electron microscope (SEM), UV-vis spectroscopy, Photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared catalysts. The CB and VB potentials of graphitic carbon nitride could be tuned from -1.09 and +1.55 eV to -0.29 and +2.25 eV by controlling the weight ratio of eutectic salts to melamine. Besides, ions doping inhibited the crystal growth of graphitic carbon nitride, enhanced the surface area, and increased the separation rate of photogenerated electrons and holes. The visible-light-driven Rhodamine B (RhB) photodegradation and mineralization performances were significantly improved after K-Na co-doping.

Temperature-controlled cross-linking of silver nanoparticles with diels-alder reaction and its application on antibacterial property

NASA Astrophysics Data System (ADS)

Liu, Lian; Yang, Pengfei; Li, Junying; Zhang, Zhiliang; Yu, Xi; Lu, Ling

2017-05-01

Sliver nanoparticles (AgNPs) were synthesized and functionalized with furan group on their surface, followed by the reverse Diels-Alder (DA) reaction with bismaleimide to vary the particle size, so as to give different antibacterial activities. These nanoparticles were characterized using Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Ultraviolet-Visible (UV-vis), Nanoparticle Size Analyzer and X-Ray Photoelectron Spectroscopy (XPS). It was found that the cross-linking reaction with bismaleimide had a great effect on the size of AgNPs. The size of the AgNPs could be controlled by the temperature of DA/r-DA equilibrium. The antibacterial activity was assessed using the inhibition zone diameter by introducing the particles into a media containing Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus, respectively. It was found that these particles were effective bactericides. Furthermore, the antibacterial activity of the nanoparticles decreased orderly as the particle size enlarged.

Synthesis and characterization of blue fluorescent surface modified nano-graphene oxide flakes as a pH-sensitive drug delivery system

NASA Astrophysics Data System (ADS)

Hashemi, Hamed; Namazi, Hassan

2018-07-01

A new blue fluorescent surface modified graphene oxide (GO) by 6-(5-bromothiophen-2-yl) benzo[c][1,2,5]selenadiazole-5-carboxylic acid (TB) denoted as (GO-TB) was synthesized. The obtained hybrid was characterized by Scanning Electron Microscope (SEM/EDS); Brunauer-Emmett-Teller (BET); X-Ray Diffraction Spectroscopy (XRD); X-Ray Photoelectron Spectroscopy (XPS); UV-Vis Absorption Spectroscopy, and Fourier Transformed Infrared Spectroscopy (FTIR). The synthesized TB moiety displayed orange emission around 590 nm, while GO-TB exhibited a blue photoluminescence around 431 and 159 nm blue shift of photoluminescence. Doxorubicin immobilized on the hybrid surface up to 93%, and the release behavior in three different pHs was investigated. The release profile indicated a pH-dependent liberation with Fickian diffusion mechanism. The cytotoxicity of the hybrid was studied and the IC50 value for the hybrid was 5.16 µg/ml.

Preparation and characteristics of epoxy/clay/B4C nanocomposite at high concentration of boron carbide for neutron shielding application

NASA Astrophysics Data System (ADS)

Kiani, Mohammad Amin; Ahmadi, Seyed Javad; Outokesh, Mohammad; Adeli, Ruhollah; Mohammadi, Aghil

2017-12-01

In this research, the characteristics of the prepared samples in epoxy matrix by means of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), as well as scanning electron microscope (SEM) are evaluated. Meanwhile, the obtained mechanical properties of the specimen are investigated. Thermogravimetric analysis (TGA) is also employed to evaluate the thermal degradation of manufactured nanocomposites. The thermal neutron absorption properties of nanocomposites containing 3 wt% of montmorillonite nanoclay (closite30B) have been studied experimentally, using an Am-Be point source. Mechanical tests reveal that the higher B4C concentrations, the more tensile strengths, but lower Young's modulus in all samples under consideration. TGA analysis also shows that thermal stability of the nanocomposite, increases in presence of B4C. Finally, neutron absorption analysis shows that increasing the B4C concentration leads to a nonlinearly build-up of neutron absorption cross section.

Microstructure and Properties of Zircon-Added Carbon Refractories for Blast Furnace

NASA Astrophysics Data System (ADS)

Zhu, Tianbin; Li, Yawei; Sang, Shaobai; Chen, Xilai; Zhao, Lei; Li, Yuanbing; Li, Shujing

2012-11-01

Microstructure and properties of zircon-added carbon refractory specimens for blast furnace (BF) were investigated with the aid of X-ray diffraction (XRD), a scanning electron microscope (SEM), energy-dispersive X-ray, mercury porosimetry, and a laser thermal conductivity (TC) meter. Additives could influence the matrix structures and improve the properties of specimens. With the increase of zircon powder content, the amount of SiC whiskers formed increased and their aspect ratio became larger, and the SiC whiskers tended to be distributed homogeneously. Zircon powder additions decreased the mean pore diameter and increased <1- μm pore volume by filling in pores via SiC, improved the TC and the cold crushing strength (CCS) due to the in-situ formation of the more well-developed SiC whiskers with high TC, and significantly reduced the molten iron attack to carbon specimens.

Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

NASA Astrophysics Data System (ADS)

Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.

2017-06-01

An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

Electron probe X-ray microanalysis of cultured myogenic C2C12 cells with scanning and scanning transmission electron microscopy.

PubMed

Tylko, G; Karasiński, J; Wróblewski, R; Roomans, G M; Kilarski, W M

2000-01-01

Heterogeneity of the elemental content of myogenic C2C12 cultured cells was studied by electron probe X-ray microanalysis (EPXMA) with scanning (SEM EPXMA) and scanning transmission electron microscopy (STEM EPXMA). The best plastic substrate for growing cells was Thermanox. For STEM EPXMA, a Formvar film coated with carbon was found to be suitable substrate. The cells examined by scanning transmission electron microscopy showed great heterogeneity in their elemental content in comparison with the cells examined in the scanning electron microscope despite of an almost identical preparation procedure for EPXMA. Nevertheless the K/Na ratios obtained from both methods of EPXMA were very close (4.1 and 4.3). We conclude that the observed discrepancy in the elemental content obtained by the two methods may be due to differences in instrumentation and this must be taken into account when planning a comparative study.

Dissolution and precipitation behaviors of silicon-containing ceramic coating on Mg-Zn-Ca alloy in simulated body fluid.

PubMed

Pan, Yaokun; Chen, Chuanzhong; Wang, Diangang; Huang, Danlan

2014-10-01

We prepared Si-containing and Si-free coatings on Mg-1.74Zn-0.55Ca alloy by micro-arc oxidation. The dissolution and precipitation behaviors of Si-containing coating in simulated body fluid (SBF) were discussed. Corrosion products were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectrometer (XPS). Electrochemical workstation, inductively coupled plasma atomic emission spectrometer (ICP-AES), flame atomic absorption spectrophotometer (AAS) and pH meter were employed to detect variations of electrochemical parameter and ions concentration respectively. Results indicate that the fast formation of calcium phosphates is closely related to the SiOx(n-) groups, which induce the heterogeneous nucleation of amorphous hydroxyapatite (HA) by sorption of calcium and phosphate ions. Copyright © 2014 Elsevier B.V. All rights reserved.

Explanation of the photocurrent generation of Cu2O quantum dots (QDs) sensitized p-CuSCN stable photoelectrochemical cells

NASA Astrophysics Data System (ADS)

Karunarathna, P. G. D. C. K.; Samarakoon, S. P. A. U. K.; Fernando, C. A. N.

2018-01-01

Fabrication of Cu2O quantum dots (QDs) sensitized p-CuSCN photoelectrode provides a significant photocurrent enhancement in photoelectrochemical medium for the first time. The variation of photocurrent quantum efficiency (Ф%) with Cu2O amount formed on p-CuSCN was presented. Here, two maxima of photocurrent could be observed in Cu/p-CuSCN/Cu2O photoelectrodes. The first photocurrent peak was due to the Cu2O QDs sensitization on p-CuSCN layer, and the second photocurrent peak was due to the formation of p-n junction. Time development of the photocurrent for Cu/p-CuSCN/n-Cu2O photoelectrodes and material characterization from Fourier transform infrared (FTIR) spectra, scanning electron microscope (SEM) images, energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD) were done in this study in detailed.

Interaction of intermetallic compound formation in Cu/SnAgCu/NiAu sandwich solder joints

NASA Astrophysics Data System (ADS)

Xia, Yanghua; Lu, Chuanyan; Chang, Junling; Xie, Xiaoming

2006-05-01

The interaction between Cu/solder interface and solder/Ni interface at a Cu/SnAgCu/NiAu sandwich solder joint with various surface finishes and solder heights was investigated. The interfacial microstructure and composition of intermetallic compounds (IMCs) were characterized by a scanning electron microscope (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX). The phase structure of IMC was identified by x-ray diffraction (XRD). It is found that ternary (Cu,Ni)6Sn5 IMCs form at both interfaces. The composition, thickness, and morphology of the ternary IMCs depend not only on the interface itself, but also on the opposite interface. That is to say, strong coupling effects exist between the two interfaces. Lattice parameters of (Cu,Ni)6Sn5 shrink with increasing Ni content, in agreement with Vegard’s law. The mechanism of ternary IMC formation and interface coupling effects are discussed in this paper.

Low Cost CaTiO3 Perovskite Synthesized from Scallop (Anadara granosa) Shell as Antibacterial Ceramic Material

NASA Astrophysics Data System (ADS)

Fatimah, Is; Nur Ilahi, Rico; Pratami, Rismayanti

2018-01-01

Research on perovskite CaTiO3 synthesis from scallop (Anadara granosa) shell and its test as material for antibacterial ceramic application have been conducted. The synthesis was performed by calcium extraction from the scallop shell followed by solid-solid reaction of obtained calcium with TiO2. Physicochemical character of the perovskite wasstudied by measurement of crystallinity using x-ray diffraction (XRD), diffuse-reflectance UV Visible spectrophotometry, scanning electrone microscope-energy dispersive x-ray (SEM-EDX) and Fourier-Transform InfraRed. Considering the future application of the perovskite as antibacterial agent, laboratory test of the peroskite as material in antibacterial ceramic preparation was also conducted. Result of research indicated that perovskite formation was obtained and the material demonstrated photocatalytic activity as identified by band gap energy (Eg) value. The significant activity was also reflected by the antibacterial action of formed ceramic.

Overview of nanoscale NEXAFS performed with soft X-ray microscopes.

PubMed

Guttmann, Peter; Bittencourt, Carla

2015-01-01

Today, in material science nanoscale structures are becoming more and more important. Not only for the further miniaturization of semiconductor devices like carbon nanotube based transistors, but also for newly developed efficient energy storage devices, gas sensors or catalytic systems nanoscale and functionalized materials have to be analysed. Therefore, analytical tools like near-edge X-ray absorption fine structure (NEXAFS) spectroscopy has to be applied on single nanostructures. Scanning transmission X-ray microscopes (STXM) as well as full-field transmission X-ray microscopes (TXM) allow the required spatial resolution to study individual nanostructures. In the soft X-ray energy range only STXM was used so far for NEXAFS studies. Due to its unique setup, the TXM operated by the Helmholtz-Zentrum Berlin (HZB) at the electron storage ring BESSY II is the first one in the soft X-ray range which can be used for NEXAFS spectroscopy studies which will be shown in this review. Here we will give an overview of the different microscopes used for NEXAFS studies and describe their advantages and disadvantages for different samples.

Scanning electron microscope/energy dispersive x ray analysis of impact residues on LDEF tray clamps

NASA Technical Reports Server (NTRS)

Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

1992-01-01

To better understand the nature of particulates in low-Earth orbit (LEO), and their effects on spacecraft hardware, we are analyzing residues found in impacts on the Long Duration Exposure Facility (LDEF) tray clamps. LDEF experiment trays were held in place by 6 to 8 chromic-anodized aluminum (6061-T6) clamps that were fastened to the spacecraft frame using three stainless steel hex bolts. Each clamp exposed an area of approximately 58 sq cm (4.8 cm x 12.7 cm x .45 cm, minus the bolt coverage). Some 337 out of 774 LDEF tray clamps were archived at JSC and are available through the Meteoroid & Debris Special Investigation Group (M&D SIG). Optical scanning of clamps, starting with Bay/Row A01 and working toward H25, is being conducted at JSC to locate and document impacts as small as 40 microns. These impacts are then inspected by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis (SEM/EDXA) to select those features which contain appreciable impact residue material. Based upon the composition of projectile remnants, and using criteria developed at JSC, we have made a preliminary discrimination between micrometeoroid and space debris residue-containing impact features. Presently, 13 impacts containing significant amounts of unmelted and semi-melted micrometeoritic residues were forwarded to Centre National d'Etudes Spatiales (CNES) in France. At the CNES facilities, the upgraded impacts were analyzed using a JEOL T330A SEM equipped with a NORAN Instruments, Voyager X-ray Analyzer. All residues were quantitatively characterized by composition (including oxygen and carbon) to help understand interplanetary dust as possibly being derived from comets and asteroids.

Microstructure and properties of laser-clad high-temperature wear-resistant alloys

NASA Astrophysics Data System (ADS)

Yang, Yongqiang

1999-02-01

A 2-kW CO 2 laser with a powder feeder was used to produce alloy coatings with high temperature-wear resistance on the surface of steel substrates. To analyze the microstructure and microchemical composition of the laser-clad layers, a scanning electron microscope (SEM) equipped with an energy dispersive X-ray microanalysis system was employed. X-ray diffraction techniques were applied to characterize the phases formed during the cladding process. The results show that the microstructure of the cladding alloy consists mainly of many dispersed particles (W 2C, (W,Ti)C 1- x, WC), a lamellar eutectic carbide M 12C, and an (f.c.c) matrix. Hardness tested at room and high temperature showed that the laser-clad zone has a moderate room temperature hardness and relatively higher elevated temperature hardness. The application of the laser-clad layer to a hot tool was very successful, and its operational life span was prolonged 1 to 4 times.

Antibacterial and cytotoxic potential of silver nanoparticles synthesized using latex of Calotropis gigantea L.

NASA Astrophysics Data System (ADS)

Rajkuberan, Chandrasekaran; Sudha, Kannaiah; Sathishkumar, Gnanasekar; Sivaramakrishnan, Sivaperumal

2015-02-01

The present study aimed to synthesis silver nanoparticles (AgNPs) in a greener route using aqueous latex extract of Calotropis gigantea L. toward biomedical applications. Initially, synthesis of AgNPs was confirmed through UV-Vis spectroscopy which shows the surface plasmonic resonance peak (SPR) at 420 nm. Fourier transform infrared spectroscopy (FTIR) analysis provides clear evidence that protein fractions present in the latex extract act as reducing and stabilizing bio agents. Energy dispersive X-ray (EDAX) spectroscopy confirms the presence of silver as a major constituent element. X-ray diffractograms displays that the synthesized AgNPs were biphasic crystalline nature. Electron microscopic studies such as Field emission scanning electron microscopic (Fe-SEM) and Transmission electron microscope (TEM) reveals that synthesized AgNPs are spherical in shape with the size range between 5 and 30 nm. Further, crude latex aqueous extract and synthesized AgNPs were evaluated against different bacterial pathogens such as Bacillus cereus, Enterococci sp, Shigella sp, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus and Escherichia coli. Compared to the crude latex aqueous extract, biosynthesized AgNPs exhibits a remarkable antimicrobial activity. Likewise invitro anticancer study manifests the cytotoxicity value of synthesized AgNPs against tested HeLa cells. The output of this study clearly suggesting that biosynthesized AgNPs using latex of C. gigantea can be used as promising nanomaterial for therapeutic application in context with nanodrug formulation.

Development of a scanning transmission x-ray microscope for the beamline P04 at PETRA III DESY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrianov, Konstantin; Ewald, Johannes; Nisius, Thomas

We present a scanning transmission x-ray microscope (STXM) built on top of our existing modular platform for high resolution imaging experiments. This platform consists of up to three separate vacuum chambers and custom designed piezo stages. These piezo stages are able to move precisely in x-, y- and z-direction, this makes it possible to adjust the components for different imaging modes. During recent experiments the endstation was operated mainly as a transmission x-ray microscope (TXM) [1, 2].

Morphological and Wear behaviour of new Al-SiCmicro-SiCnano hybrid nanocomposites fabricated through powder metallurgy

NASA Astrophysics Data System (ADS)

Arif, Sajjad; Tanwir Alam, Md; Aziz, Tariq; Ansari, Akhter H.

2018-04-01

In the present work, aluminium matrix composites reinforced with 10 wt% SiC micro particles along with x% SiC nano particles (x = 0, 1, 3, 5 and 7 wt%) were fabricated through powder metallurgy. The fabricated hybrid composites were characterized by x-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrum (EDS) and elemental mapping. The relative density, hardness and wear behaviour of all hybrid nanocomposites were studied. The influence of various control factors like SiC reinforcement, sliding distance (300, 600, 900 and 1200 m) and applied load (20, 30 and 40 N) were explored using pin-on-disc wear apparatus. The uniform distribution of micro and nano SiC particles in aluminium matrix is confirmed by elemental maps. The hardness and wear test results showed that properties of the hybrid composite containing 5 wt% nano SiC was better than other hybrid composites. Additionally, the wear loss of all hybrid nanocomposites increases with increasing sliding distance and applied load. The identification of wear phenomenon were studied through the SEM images of worn surface.

X-ray/EUV optics for astronomy, microscopy, polarimetry, and projection lithography; Proceedings of the Meeting, San Diego, CA, July 9-13, 1990

NASA Technical Reports Server (NTRS)

Hoover, Richard B. (Editor); Walker, Arthur B. C., Jr. (Editor)

1991-01-01

Topics discussed in this issue include the fabrication of multilayer X-ray/EUV coatings; the design, characterization, and test of multilayer X-ray/EUV coatings; multilayer X-ray/EUV monochromators and imaging microscopes; X-ray/EUV telescopes; the test and calibration performance of X-ray/EUV instruments; XUV/soft X-ray projection lithography; X-ray/EUV space observatories and missions; X-ray/EUV telescopes for solar research; X-ray/EUV polarimetry; X-ray/EUV spectrographs; and X-ray/EUV filters and gratings. Papers are presented on the deposition-controlled uniformity of multilayer mirrors, interfaces in Mo/Si multilayers, the design and analysis of an aspherical multilayer imaging X-ray microscope, recent developments in the production of thin X-ray reflecting foils, and the ultraprecise scanning technology. Consideration is also given to an active sun telescope array, the fabrication and performance at 1.33 nm of a 0.24-micron-period multilayer grating, a cylindrical proportional counter for X-ray polarimetry, and the design and analysis of the reflection grating arrays for the X-Ray Multi-Mirror Mission.

Synthesis, characterization, in vitro anti-proliferative and hemolytic activity of hydroxyapatite.

PubMed

Palanivelu, R; Ruban Kumar, A

2014-06-05

Hydroxyapatite (Ca10(PO4)6(OH)2, HAP) nanoparticles are widely used in several biomedical applications due to its compositional similarities to bone mineral, excellent biocompatibility and bioactivity, osteoconductivity. In this present investigation, HAP nanoparticles synthesized by precipitation technique using calcium nitrate and di-ammonium phosphate. The crystalline nature and the functional group analysis are confirmed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Fourier transform Raman spectroscopy (FT-Raman) respectively. The morphological observations are ascertained from field emission electron scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). In vitro anti-proliferative and hemolytic activities are carried out on the synthesized HAP samples and the studies reveals that HAP have mild activity against erythrocytes. Copyright © 2014 Elsevier B.V. All rights reserved.

Microstructural and thermal study of Al-Si-Mg/melon shell ash particulate composite

NASA Astrophysics Data System (ADS)

Abdulwahab, M.; Umaru, O. B.; Bawa, M. A.; Jibo, H. A.

The microstructural study via scanning electron microscope (SEM) and thermal study via differential scanning calorimetric (DSC) study of Al-7%Si-0.3Mg/melon shell ash particulate composite has been carried out. The melon shell ash was used in the production of MMC ranging from 5% to 20% at interval of 5% addition using stir casting method. The melon shell ash was characterized using X-ray fluorescent (XRF) that reveal the presence of CaO, SiO2, Al2O3, MgO, and TiO2 as major compounds. The composite was machined and subjected to heat treatment. Microstructural analyses of the composite produced were done using scanning electron microscope (SEM). The microstructure obtained reveals a dark ceramic (reinforcer) and white metallic phase. Equally, the 5 wt% DSC result gives better thermal conductivity than other proportions (10 wt%, 15 wt%, and 20 wt%). These results showed that an improved property of Al-Si-Mg alloy was achieved using melon shell ash particles as reinforcement up to a maximum of 20 wt% for microstructural and 5% wt DSC respectively.

Benefits from bremsstrahlung distribution evaluation to get unknown information from specimen in SEM and TEM

NASA Astrophysics Data System (ADS)

Eggert, F.; Camus, P. P.; Schleifer, M.; Reinauer, F.

2018-01-01

The energy-dispersive X-ray spectrometer (EDS or EDX) is a commonly used device to characterise the composition of investigated material in scanning and transmission electron microscopes (SEM and TEM). One major benefit compared to wavelength-dispersive X-ray spectrometers (WDS) is that EDS systems collect the entire spectrum simultaneously. Therefore, not only are all emitted characteristic X-ray lines in the spectrum, but also the complete bremsstrahlung distribution is included. It is possible to get information about the specimen even from this radiation, which is usually perceived more as a disturbing background. This is possible by using theoretical model knowledge about bremsstrahlung excitation and absorption in the specimen in comparison to the actual measured spectrum. The core aim of this investigation is to present a method for better bremsstrahlung fitting in unknown geometry cases by variation of the geometry parameters and to utilise this knowledge also for characteristic radiation evaluation. A method is described, which allows the parameterisation of the true X-ray absorption conditions during spectrum acquisition. An ‘effective tilt’ angle parameter is determined by evaluation of the bremsstrahlung shape of the measured SEM spectra. It is useful for bremsstrahlung background approximation, with exact calculations of the absorption edges below the characteristic peaks, required for P/B-ZAF model based quantification methods. It can even be used for ZAF based quantification models as a variable input parameter. The analytical results are then much more reliable for the different absorption effects from irregular specimen surfaces because the unknown absorption dependency is considered. Finally, the method is also applied for evaluation of TEM spectra. In this case, the real physical parameter optimisation is with sample thickness (mass thickness), which is influencing the emitted and measured spectrum due to different absorption with TEM measurements. The effects are in the very low energy part of the spectrum, and are much more visible with most recent windowless TEM detectors. The thickness of the sample can be determined in this way from the measured bremsstrahlung spectrum shape.

Room Temperature Elastic Moduli and Vickers Hardness of Hot-Pressed LLZO Cubic Garnet

DTIC Science & Technology

2012-01-01

polishing compounds, Leco, St. Joseph, MI). X - ray diffraction and scanning electron microscopy (SEM) The microstructure of the hot-pressed specimens...was examined on uncoated fracture surfaces by SEM with an accelerating voltage of 1 and 3 kV. Phase purity was evaluated from X - ray diffraction data...the micro- structure appeared to be homogenous for the two hot- pressed LLZO specimens included in this study (Fig. 1). X - ray diffraction confirmed that

Photo-induced self-cleaning and sterilizing activity of Sm3+ doped ZnO nanomaterials.

PubMed

Saif, M; Hafez, H; Nabeel, A I

2013-01-01

Highly active samarium doped zinc oxide self-cleaning and biocidal surfaces (x mol% Sm(3+)/ZnO where x=0, 1, 2 and 4 mol%) with crystalline porous structures were synthesized by hydrothermal method. Sm(3+)/ZnO thin films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopic (EDS), UV-visible diffuse reflectance and fluorescence (FL) spectroscopy. The combination between doping and hydrothermal treatments significantly altered the morphology of ZnO into rod and plate-like nanoshapes structure and enhanced its absorption and emission of ultraviolet radiation. The photo-activity in term of quantitative determination of the active oxidative species (()OH) produced on the thin film surfaces was evaluated using fluorescent probe method. The results showed that, the hydrothermally treated 2.0 mol% Sm(3+)/ZnO film (S2) is the highly active one. The optical, structural, morphology and photo-activity properties of the highly active thin film (S2) make it promising surface for self-cleaning and sterilizing applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

Calcinations effect on the grain size distributions Al2O3 powder

NASA Astrophysics Data System (ADS)

Issa, Tarik Talib; Mohammed, Awattif A.; Kamil, Dunia

2012-09-01

Fine of Al2O3 Powder was calcined at 200°C, 400°C, 600°C, and 800°C respectively for 2 hours under static air, x-ray diffraction, optical microscope and grain size distribution were done to analysis the resulting data after calcinations process. Batter particle size was achieved at 800°C of value (0.486) μm, while batter particles mean value of size 7.18 μm was found at 400°C. SEM micrographs shows that the agglomerate particles were vanished due to the calcinations process.

Spectroscopic characterization of nanohydroxyapatite synthesized by molten salt method.

PubMed

Gopi, D; Indira, J; Kavitha, L; Kannan, S; Ferreira, J M F

2010-10-01

Hydroxyapatite (HAP) nanopowders were synthesized by molten salt method at 260 degrees C. The as-prepared powders were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo gravimetric analysis (TGA). With the aid of the obtained results the effect of calcining time on the crystallinity, size and morphology of HAP nanopowders is presented. The HAP nanopowders synthesized by molten salt method consist of pure phase of HAP without any impurities and showed the rod-like morphology without detectable decomposition up to 1100 degrees C. Copyright 2010 Elsevier B.V. All rights reserved.

The preparation and characterization of silk fibroin blended with low molecular weight hydroxypropyl methylcellulose (HPMC)

NASA Astrophysics Data System (ADS)

Shetty, G. Rajesha; Rao, B. Lakshmeesha; Gowda, Mahadeva; Shivananda, C. S.; Asha, S.; Sangappa, Y.

2018-04-01

In this work, the structure and optical properties of Silk Fibroin (SF), lower molecular weight Hydroxypropyl Methylcellulose (HPMC(L)) and its blend film of SF-HPMC(L) were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron Microscope (SEM) and UV-Visible spectroscopy (UV-Vis). The results indicates that the homogeneous miscible blend of SF-HPMC(L) has lower crystallite size and lower optical band gap compared to virgin SF and HPMC(L). FTIR study confirms the presence of both SF and HPMC(L) molecules in the prepared blend films.

Optical, electrical and ferromagnetic studies of ZnO:Fe diluted magnetic semiconductor nanoparticles for spintronic applications

NASA Astrophysics Data System (ADS)

Elilarassi, R.; Chandrasekaran, G.

2017-11-01

In the present investigation, diluted magnetic semiconductor (Zn1-xFexO) nanoparticles with different doping concentrations (x = 0, 0.02, 0.04, 0.06, and 0.08) were successfully synthesized by sol-gel auto-combustion method. The crystal structure, morphology, optical, electrical and magnetic properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis using x-rays (EDAX), ultraviolet-visible spectrophotometer, fluorescence spectroscope (FS), vibrating sample magnetometer (VSM) and broad band dielectric spectrometer (BDS). XRD results reveal that all the samples possess hexagonal wurtzite crystal structure with good crystalline quality. The absence of impurity phases divulge that Fe ions are well incorporated into the ZnO crystal lattice. The substitutional incorporation of Fe3+ at Zn sites is reflected in optical absorption spectra of the samples. Flouorescence spectra of the samples show a strong near-band edge related UV emission as well as defect related visible emissions. The semiconducting behavior of the samples has been confirmed through electrical conductivity measurements. Magnetic measurements indicated that all the samples possess ferromagnetism at room temperature.

Calcination temperature effect on the microstructure and dielectric properties of M-type strontium hexagonal ferrites

NASA Astrophysics Data System (ADS)

Mohammed, J.; Sharma, Jyoti; Kumar, Sachin; Trudel, T. T. Carol; Srivastava, A. K.

2017-07-01

M-type hexagonal ferrites have found wide application in electronics industry due to the possibility of tuning properties such as dielectric properties. An improved dielectric property is useful in high frequency application. In this paper, we studied the effect of calcination temperature on structural and dielectric properties of Al-Mn substituted M-type strontium hexagonal ferrites with chemical composition Sr1-xAlxFe12-yMnyO19 (x=0.3 and y=0.6) synthesized by sol-gel auto-combustion method. The prepared sample was sintered at four different temperatures (T=750°C, 850°C, 950°C and 1050°C) for 5 hours. Characterisations of the synthesized samples were carried out using X-ray diffraction (XRD), impedance analyser, field emission electron microscope (FE-SEM) and energy dispersive X-ray (EDX) spectroscopy. The dielectric properties were explained on the basis of Koop's phenomenological theory and Maxwell Wagner theory. The sample calcinated at 750°C shows the highest value of dielectric constant and AC conductivity whereas that calcinated at 1050°C exhibit the lowest dielectric losses.

Scanning force microscope for in situ nanofocused X-ray diffraction studies

PubMed Central

Ren, Zhe; Mastropietro, Francesca; Davydok, Anton; Langlais, Simon; Richard, Marie-Ingrid; Furter, Jean-Jacques; Thomas, Olivier; Dupraz, Maxime; Verdier, Marc; Beutier, Guillaume; Boesecke, Peter; Cornelius, Thomas W.

2014-01-01

A compact scanning force microscope has been developed for in situ combination with nanofocused X-ray diffraction techniques at third-generation synchrotron beamlines. Its capabilities are demonstrated on Au nano-islands grown on a sapphire substrate. The new in situ device allows for in situ imaging the sample topography and the crystallinity by recording simultaneously an atomic force microscope (AFM) image and a scanning X-ray diffraction map of the same area. Moreover, a selected Au island can be mechanically deformed using the AFM tip while monitoring the deformation of the atomic lattice by nanofocused X-ray diffraction. This in situ approach gives access to the mechanical behavior of nanomaterials. PMID:25178002

WC/Co composite surface structure and nano graphite precipitate induced by high current pulsed electron beam irradiation

NASA Astrophysics Data System (ADS)

Hao, S. Z.; Zhang, Y.; Xu, Y.; Gey, N.; Grosdidier, T.; Dong, C.

2013-11-01

High current pulsed electron beam (HCPEB) irradiation was conducted on a WC-6% Co hard alloy with accelerating voltage of 27 kV and pulse duration of 2.5 μs. The surface phase structure was examined by using glancing-angle X-ray diffraction (GAXRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) methods. The surface tribological properties were measured. It was found that after 20 pulses of HCPEB irradiation, the surface structure of WC/Co hard alloy was modified dramatically and composed of a mixture of nano-grained WC1-x, Co3W9C4, Co3W3C phases and graphite precipitate domains ˜50 nm. The friction coefficient of modified surface decreased to ˜0.38 from 0.6 of the initial state, and the wear rate reduced from 8.4 × 10-5 mm3/min to 6.3 × 10-6 mm3/min, showing a significant self-lubricating effect.

X-ray transmission microscope development

NASA Technical Reports Server (NTRS)

Kaukler, William F.; Rosenberger, Franz E.

1995-01-01

We are developing a hard x-ray microscope for direct observation of solidification dynamics in metal alloys and metal matrix composites. The Fein-Focus Inc. x-ray source was delivered in September and found to perform better than expected. Confirmed resolution of better than 2 micrometers was obtained and magnifications up to 800X were measured. Nickel beads of 30 micrometer diameter were easily detected through 6mm of aluminum. X-ray metallography was performed on several specimens showing high resolution and clear definition of 3-dimensional structures. Prototype furnace installed and tested.

Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source

NASA Astrophysics Data System (ADS)

Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

2014-09-01

We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source.

PubMed

Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

2014-09-01

We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

Soft x-ray spectromicroscopy using compact scanning transmission x-ray microscope at the photon factory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeichi, Yasuo, E-mail: yasuo.takeichi@kek.jp; Inami, Nobuhito; Ono, Kanta

We report the stability and recent performances of a new type of scanning transmission X-ray microscopy. The optics and compact design of the microscope realized mobility and robust performance. Detailed consideration to the vibration control will be described. The insertion device upgraded to elliptical polarization undulator enabled linear dichroism and circular dichroism experiments.

Sub-micrometer resolution proximity X-ray microscope with digital image registration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chkhalo, N. I.; Salashchenko, N. N.; Sherbakov, A. V., E-mail: SherbakovAV@ipm.sci-nnov.ru

A compact laboratory proximity soft X-ray microscope providing submicrometer spatial resolution and digital image registration is described. The microscope consists of a laser-plasma soft X-ray radiation source, a Schwarzschild objective to illuminate the test sample, and a two-coordinate detector for image registration. Radiation, which passes through the sample under study, generates an absorption image on the front surface of the detector. Optical ceramic YAG:Ce was used to convert the X-rays into visible light. An image was transferred from the scintillator to a charge-coupled device camera with a Mitutoyo Plan Apo series lens. The detector’s design allows the use of lensesmore » with numerical apertures of NA = 0.14, 0.28, and 0.55 without changing the dimensions and arrangement of the elements of the device. This design allows one to change the magnification, spatial resolution, and field of view of the X-ray microscope. A spatial resolution better than 0.7 μm and an energy conversion efficiency of the X-ray radiation with a wavelength of 13.5 nm into visible light collected by the detector of 7.2% were achieved with the largest aperture lens.« less

Elemental composition study of heavy metal (Ni, Cu, Zn) in riverbank soil by electrokinetic-assisted phytoremediation using XRF and SEM/EDX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamari, Suhailly; Embong, Zaidi; Bakar, Ismail

Electrokinetic (EK)-assisted phytoremediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phytoremediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6V/cm{sup −1} electric field for 4 hours/day, the soil and plant samples were analyzedmore » using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phytoremediation plant powder samples had increase while elemental concentrations in the post-phytoremediation soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phytoremediation process has increase the efficiency of plant uptake.« less

Three-dimensional multiscale analysis of degradation of nano- and micro-structure in direct methanol fuel cell electrodes after methanol starvation

NASA Astrophysics Data System (ADS)

Netzeband, Christian; Arlt, Tobias; Wippermann, Klaus; Lehnert, Werner; Manke, Ingo

2016-09-01

This study investigates the ageing effects on the microstructure of the anode catalyst layer of direct methanol fuel cells (DMFC) after complete methanol starvation. To this end the samples of two methanol-depleted membrane electrode assemblies (MEA) have been compared with a pristine reference sample. A three-dimensional characterization of the anode catalyst layer (ACL) structure on a nanometer scale has been conducted by focused ion beam (FIB)/scanning electron microscope (SEM) tomography. The FIB/SEM tomography allows for a detailed analysis of statistic parameters of micro-structured materials, such as porosity, tortuosity and pore size distributions. Furthermore, the SEM images displayed a high material contrast between the heavy catalyst metals (Pt/Ru) and the relatively light carbon support, which made it possible to map the catalyst distribution in the acquired FIB/SEM tomographies. Additional synchrotron X-ray tomographies have been conducted in order to obtain an overview of the structural changes of all the components of a section of the MEAs after methanol depletion.

Properties of magnetic iron oxides used as materials for wastewater treatment

NASA Astrophysics Data System (ADS)

Matei, E.; Predescu, A.; Vasile, E.; Predescu, A.

2011-07-01

The paper describes the properties of some nanopowders obtained by coprecipitation and used as adsorbent for wastewater treatment. The Fe3O4 and γ-Fe2O3 nanopowders were obtained using iron salts and NaOH as precipitation agents. D-sorbitol was used to prevent the agglomeration between the nanoparticles. The particle size and distribution were detected using a transmission electron microscopy (TEM) and a scanning electron microscope (SEM) equipped with dispersive analyze system in X radiation energy (EDS). The structure of the iron oxide nanoparticles was characterized by X-ray powder diffraction. Thus, the nanoparticles were characterized and compare in terms of particle size and chemical composition and used for adsorption studies in order to removal hexavalent chromium from waste waters.

Photoluminescence studies on Cd(1-x)Zn(x)S:Mn2+ nanocrystals.

PubMed

Sethi, Ruchi; Kumar, Lokendra; Pandey, A C

2009-09-01

Highly monodispersed, undoped and doped with Mn2+, binary and ternary (CdS, ZnS, Cd(1-x)Zn(x)S) compound semiconductor nanocrystals have been synthesized by co-precipitation method using citric acid as a stabilizer. As prepared sample are characterized by X-ray diffraction, Small angle X-ray scattering, Transmission electron microscope, Optical absorption and Photoluminescence spectroscopy, for their optical and structural properties. X-ray diffraction, Small angle X-ray scattering and Transmission electron microscope results confirm the preparation of monodispersed nanocrystals. Photoluminescence studies show a significant blue shift in the wavelength with an increasing concentration of Zn in alloy nanocrystals.

Fabricating the spherical and flake silver powder used for the optoelectronic devices

NASA Astrophysics Data System (ADS)

Ju, Wei; Ma, Wangjing; Zhang, Fangzhi; Chen, Yixiang; Xie, Jinpeng

2018-01-01

The spherical and flake silver powder with different particle size for the optoelectronic devices was partly prepared by using chemical reduction and ball milling method, and charactered by scanning electron microscope (SEM), X-ray diffraction (XRD), laser particle size analyzer and thermo-gravimetric(TG) analyzer. The particle size of three series of spherical silver powder fabricated by chemical reduction is about 1.5μm, 1μm and 0.6μm, respectively; after being mechanical milling, the particle size of flake silver powder with high flaky rate is about 10μm, 6μm and 2μm respectively. Thermo gravimetric (TG) and XRD analyses showed that the silver powders have high purity and crystalline, and then the laser particle size and SEM analyses showed that the silver powders has good uniformity.

Insitu grown superhydrophobic Zn-Al layered double hydroxides films on magnesium alloy to improve corrosion properties

NASA Astrophysics Data System (ADS)

Zhou, Meng; Pang, Xiaolu; Wei, Liang; Gao, Kewei

2015-05-01

A hierarchical superhydrophobic zinc-aluminum layered double hydroxides (Zn-Al LDHs) film has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method following chemical modification. The characteristics of the films were investigated by X-ray diffraction (XRD), scanning electronic microscope (SEM), and energy dispersive spectroscopy (EDS). XRD patterns and SEM images showed that the micro/nanoscale hierarchical LDHs film surfaces composed of ZnO nanorods and Zn-Al LDHs nanowalls structures. The static contact angle (CA) for the prepared surfaces was observed at around 165.6°. The corrosion resistance of the superhydrophobic films was estimated by electrochemical impedance spectroscopy (EIS) and potentiondynamic polarization measurement. EIS and polarization measurements revealed that the superhydrophobic Zn-Al LDHs coated magnesium alloy had better corrosion resistance in neutral 3.5 wt.% NaCl solution.

Cryo X-ray microscope with flat sample geometry for correlative fluorescence and nanoscale tomographic imaging.

PubMed

Schneider, Gerd; Guttmann, Peter; Rehbein, Stefan; Werner, Stephan; Follath, Rolf

2012-02-01

X-ray imaging offers a new 3-D view into cells. With its ability to penetrate whole hydrated cells it is ideally suited for pairing fluorescence light microscopy and nanoscale X-ray tomography. In this paper, we describe the X-ray optical set-up and the design of the cryo full-field transmission X-ray microscope (TXM) at the electron storage ring BESSY II. Compared to previous TXM set-ups with zone plate condenser monochromator, the new X-ray optical layout employs an undulator source, a spherical grating monochromator and an elliptically shaped glass capillary mirror as condenser. This set-up improves the spectral resolution by an order of magnitude. Furthermore, the partially coherent object illumination improves the contrast transfer of the microscope compared to incoherent conditions. With the new TXM, cells grown on flat support grids can be tilted perpendicular to the optical axis without any geometrical restrictions by the previously required pinhole for the zone plate monochromator close to the sample plane. We also developed an incorporated fluorescence light microscope which permits to record fluorescence, bright field and DIC images of cryogenic cells inside the TXM. For TXM tomography, imaging with multi-keV X-rays is a straightforward approach to increase the depth of focus. Under these conditions phase contrast imaging is necessary. For soft X-rays with shrinking depth of focus towards 10nm spatial resolution, thin optical sections through a thick specimen might be obtained by deconvolution X-ray microscopy. As alternative 3-D X-ray imaging techniques, the confocal cryo-STXM and the dual beam cryo-FIB/STXM with photoelectron detection are proposed. Copyright © 2012 Elsevier Inc. All rights reserved.

A combined scanning tunnelling microscope and x-ray interferometer

NASA Astrophysics Data System (ADS)

Yacoot, Andrew; Kuetgens, Ulrich; Koenders, Ludger; Weimann, Thomas

2001-10-01

A monolithic x-ray interferometer made from silicon and a scanning tunnelling microscope have been combined and used to calibrate grating structures with periodicities of 100 nm or less. The x-ray interferometer is used as a translation stage which moves in discrete steps of 0.192 nm, the lattice spacing of the silicon (220) planes. Hence, movements are traceable to the definition of the metre and the nonlinearity associated with the optical interferometers used to measure displacement in more conventional metrological scanning probe microscopes (MSPMs) removed.

Hard X-Ray Scanning Microscope with Multilayer Laue Lens Nanofocusing Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazaretski, Evgeny

Evgeny Nazaretski, a physicist at Brookhaven Lab’s National Synchrotron Light Source II, spearheaded the development of a one-of-a-kind x-ray microscope with novel nanofocusing optics called multilayer Laue lenses.

Design and performance of an X-ray scanning microscope at the Hard X-ray Nanoprobe beamline of NSLS-II

DOE PAGES

Nazaretski, E.; Yan, H.; Lauer, K.; ...

2017-10-05

A hard X-ray scanning microscope installed at the Hard X-ray Nanoprobe beamline of the National Synchrotron Light Source II has been designed, constructed and commissioned. The microscope relies on a compact, high stiffness, low heat dissipation approach and utilizes two types of nanofocusing optics. It is capable of imaging with ~15 nm × 15 nm spatial resolution using multilayer Laue lenses and 25 nm × 26 nm resolution using zone plates. Fluorescence, diffraction, absorption, differential phase contrast, ptychography and tomography are available as experimental techniques. The microscope is also equipped with a temperature regulation system which allows the temperature ofmore » a sample to be varied in the range between 90 K and 1000 K. The constructed instrument is open for general users and offers its capabilities to the material science, battery research and bioscience communities.« less

Design and performance of an X-ray scanning microscope at the Hard X-ray Nanoprobe beamline of NSLS-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazaretski, E.; Yan, H.; Lauer, K.

A hard X-ray scanning microscope installed at the Hard X-ray Nanoprobe beamline of the National Synchrotron Light Source II has been designed, constructed and commissioned. The microscope relies on a compact, high stiffness, low heat dissipation approach and utilizes two types of nanofocusing optics. It is capable of imaging with ~15 nm × 15 nm spatial resolution using multilayer Laue lenses and 25 nm × 26 nm resolution using zone plates. Fluorescence, diffraction, absorption, differential phase contrast, ptychography and tomography are available as experimental techniques. The microscope is also equipped with a temperature regulation system which allows the temperature ofmore » a sample to be varied in the range between 90 K and 1000 K. The constructed instrument is open for general users and offers its capabilities to the material science, battery research and bioscience communities.« less

Thickness determination of large-area films of yttria-stabilized zirconia produced by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Pryds, N.; Toftmann, B.; Bilde-Sørensen, J. B.; Schou, J.; Linderoth, S.

2006-04-01

Films of yttria-stabilized zirconia (YSZ) on a polished silicon substrate of diameter up to 125 mm have been produced in a large-area pulsed laser deposition (PLD) setup under typical PLD conditions. The film thickness over the full film area has been determined by energy-dispersive X-ray spectrometry in a scanning electron microscope (SEM) with use of a method similar to one described by Bishop and Poole. The attenuation of the electron-induced X-rays from the Si wafer by the film was monitored at a number of points along a diameter and the thickness was determined by Monte Carlo simulations of the attenuation for various values of film thickness with the program CASINO. These results have been compared with direct measurements in the SEM of the film thickness on a cross-section on one of the wafers. The results of these measurements demonstrate the ability of this technique to accurately determine the thickness of a large film, i.e. up to diameters of 125 mm, in a relatively short time, without destroying the substrate, without the need of a standard sample and without the need of a flat substrate. We have also demonstrated that by controlling the deposition parameters large-area YSZ films with uniform thickness can be produced.

Phase transformation from cubic ZnS to hexagonal ZnO by thermal annealing

NASA Astrophysics Data System (ADS)

Mahmood, K.; Asghar, M.; Amin, N.; Ali, Adnan

2015-03-01

We have investigated the mechanism of phase transformation from ZnS to hexagonal ZnO by high-temperature thermal annealing. The ZnS thin films were grown on Si (001) substrate by thermal evaporation system using ZnS powder as source material. The grown films were annealed at different temperatures and characterized by X-ray diffraction (XRD), photoluminescence (PL), four-point probe, scanning electron microscope (SEM) and energy dispersive X-ray diffraction (EDX). The results demonstrated that as-deposited ZnS film has mixed phases but high-temperature annealing leads to transition from ZnS to ZnO. The observed result can be explained as a two-step process: (1) high-energy O atoms replaced S atoms in lattice during annealing process, and (2) S atoms diffused into substrate and/or diffused out of the sample. The dissociation energy of ZnS calculated from the Arrhenius plot of 1000/T versus log (resistivity) was found to be 3.1 eV. PL spectra of as-grown sample exhibits a characteristic green emission at 2.4 eV of ZnS but annealed samples consist of band-to-band and defect emission of ZnO at 3.29 eV and 2.5 eV respectively. SEM and EDX measurements were additionally performed to strengthen the argument.

Chemical and microstructural analyses for heavy metals removal from water media by ceramic membrane filtration.

PubMed

Ali, Asmaa; Ahmed, Abdelkader; Gad, Ali

2017-01-01

This study aims to investigate the ability of low cost ceramic membrane filtration in removing three common heavy metals namely; Pb 2+ , Cu 2+ , and Cd 2+ from water media. The work includes manufacturing ceramic membranes with dimensions of 15 by 15 cm and 2 cm thickness. The membranes were made from low cost materials of local clay mixed with different sawdust percentages of 0.5%, 2.0%, and 5.0%. The used clay was characterized by X-ray diffraction (XRD) and X-ray fluorescence analysis. Aqueous solutions of heavy metals were prepared in the laboratory and filtered through the ceramic membranes. The influence of the main parameters such as pH, initial driving pressure head, and concentration of heavy metals on their removal efficiency by ceramic membranes was investigated. Water samples were collected before and after the filtration process and their heavy metal concentrations were determined by chemical analysis. Moreover, a microstructural analysis using scanning electronic microscope (SEM) was performed on ceramic membranes before and after the filtration process. The chemical analysis results showed high removal efficiency up to 99% for the concerned heavy metals. SEM images approved these results by showing adsorbed metal ions on sides of the internal pores of the ceramic membranes.

Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

DOE PAGES

Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.; ...

2016-02-05

Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.

Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

Impact of Oriented Clay Particles on X-Ray Spectroscopy Analysis

NASA Astrophysics Data System (ADS)

Lim, A. J. M. S.; Syazwani, R. N.; Wijeyesekera, D. C.

2016-07-01

Understanding the engineering properties of the mineralogy and microfabic of clayey soils is very complex and thus very difficult for soil characterization. Micromechanics of soils recognize that the micro structure and mineralogy of clay have a significant influence on its engineering behaviour. To achieve a more reliable quantitative evaluation of clay mineralogy, a proper sample preparation technique for quantitative clay mineral analysis is necessary. This paper presents the quantitative evaluation of elemental analysis and chemical characterization of oriented and random oriented clay particles using X-ray spectroscopy. Three different types of clays namely marine clay, bentonite and kaolin clay were studied. The oriented samples were prepared by placing the dispersed clay in water and left to settle on porous ceramic tiles by applying a relatively weak suction through a vacuum pump. Images form a Scanning Electron Microscope (SEM) was also used to show the comparison between the orientation patterns of both the sample preparation techniques. From the quantitative analysis of the X-ray spectroscopy, oriented sampling method showed more accuracy in identifying mineral deposits, because it produced better peak intensity on the spectrum and more mineral content can be identified compared to randomly oriented samples.

Structural, Morphological, Differential Scanning Calorimetric and Thermogravimetric Studies of Ball Milled Fe Doped Nanoscale La0.67Sr0.33MnO3 Manganite

NASA Astrophysics Data System (ADS)

Astik, Nidhi; Jha, Prafulla K.; Pratap, Arun

2018-03-01

The ball milling route has been used to produce the La0.67Sr0.33Mn0.85Fe0.15O3 (LSMFO) nanocrystalline sample from oxide precursors. The sample was characterized using x-ray diffraction (XRD), a scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDAX), differential scanning calorimetry (DSC) and thermogravimetric (TGA) measurements. The x-ray diffraction confirms the phase purity of sample and shows that the sample crystallizes in the rhombohedral perovskite structure with a R-3c space group. The scanning electron micrograph shows the presence of well-faceted crystallites of LSMFO. The EDAX spectrum demonstrates the molar ratio of different elements of nanocrystalline LSMFO. Furthermore, the crystallite size using the Debye-Scherrer formula and William-Hall analysis has been found as 24 nm and 29 nm, respectively. Our results support the idea that a good quality nanocrystalline LSMFO sample can be obtained using the ball milling route. We also discuss the DSC and TGA curves and analyse the results in terms of phase transition, calcination temperature and activation barrier energies.

Enhanced efficiency of luminescence with stoichiometry control in LiGd(W(1-x)MoxO4)2:Eu3+ red phosphors

NASA Astrophysics Data System (ADS)

Kavi Rasu, K.; Balaji, D.; Moorthy Babu, S.

2017-06-01

A series of LiGd(W(1-x)MoxO4)2 [hereafter LGWM]:Eu3+(x=0.00 to 1.00) red-emitting phosphors were synthesized by sol-gel method. Metal nitrates were used as starting materials with citric acid as chelator and ethylene glycol as binder. Synthesized gel was pre-fired at 523 K and calcined at 1073 K using resistive furnace in air atmosphere. The crystallinity, surface morphology and luminescent properties of the phosphors were investigated using powder X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectrophotometry respectively. The intensity of the red emission at 615 nm for 5D0→7F2 electric dipole transition increases as the content of Mo6+ was increased and reach a maximum, when the relative ratio of W/Mo is 1:1 under 396 nm excitation.

Table-top soft x-ray microscope using laser-induced plasma from a pulsed gas jet.

PubMed

Müller, Matthias; Mey, Tobias; Niemeyer, Jürgen; Mann, Klaus

2014-09-22

An extremely compact soft x-ray microscope operating in the "water window" region at the wavelength λ = 2.88 nm is presented, making use of a long-term stable and nearly debris-free laser-induced plasma from a pulsed nitrogen gas jet target. The well characterized soft x-ray radiation is focused by an ellipsoidal grazing incidence condenser mirror. Imaging of a sample onto a CCD camera is achieved with a Fresnel zone plate using magnifications up to 500x. The spatial resolution of the recorded microscopic images is about 100 nm as demonstrated for a Siemens star test pattern.

Light-responsive smart surface with controllable wettability and excellent stability.

PubMed

Zhou, Yin-Ning; Li, Jin-Jin; Zhang, Qing; Luo, Zheng-Hong

2014-10-21

Novel fluorinated gradient copolymer was designed for smart surface with light-responsive controllable wettability and excellent stability. The switchable mechanism and physicochemical characteristics of the as-prepared surface decorated by designed polymeric material were investigated by ultraviolet-visible (UV-vis) spectrum, scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Thanks to the functional film and surface roughening, etched silicon surface fabricated by copolymer involving spiropyran (Sp) moieties possesses a fairly large variation range of WCA (28.1°) and achieves the transformation between hydrophilicity (95.2° < 109.2°) and hydrophobicity (123.3° > 109.2°) relative to blank sample (109.2°). The synthetic strategy and developed smart surface offer a promising application in coating with controllable wettability, which bridge the gap between chemical structure and material properties.

Hard X-Ray Scanning Microscope with Multilayer Laue Lens Nanofocusing Optics

ScienceCinema

Nazaretski, Evgeny

2018-06-13

Evgeny Nazaretski, a physicist at Brookhaven Lab’s National Synchrotron Light Source II, spearheaded the development of a one-of-a-kind x-ray microscope with novel nanofocusing optics called multilayer Laue lenses.

Nm-scale spatial resolution x-ray imaging with MLL nanofocusing optics: instrumentational requirements and challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazaretski, E.; Yan, H.; Lauer, K.

2016-08-30

The Hard X-ray Nanoprobe (HXN) beamline at NSLS-II has been designed and constructed to enable imaging experiments with unprecedented spatial resolution and detection sensitivity. The HXN X-ray Microscope is a key instrument for the beamline, providing a suite of experimental capabilities which includes scanning fluorescence, diffraction, differential phase contrast and ptychography utilizing Multilayer Laue Lenses (MLL) and zoneplate (ZP) as nanofocusing optics. In this paper, we present technical requirements for the MLL-based scanning microscope, outline the development concept and present first ~15 x 15 nm 2 spatial resolution x-ray fluorescence images.

Imaging Research With Non-Periodic Multilayers for Inertial Confinement Fusion Diagnostic Experiments

NASA Astrophysics Data System (ADS)

L. Wang, F.; Mu, B. Z.; Wang, Z. S.; Gu, C. S.; Zhang, Z.; Qin, S. J.; Chen, L. Y.

A grazing Kirkpatrick-Baez (K-B) microscope was designed for hard x-ray (8keV; Cu Ka radiation) imaging in Inertial Confinement Fusion (ICF) diagnostic experiments. Ray tracing software was used to simulate optical system performance. The optimized theoretical resolution of K-B microscope was about 2 micron and better than 10 micron in 200 micron field of view. Tungsten and boron carbide were chosen as multilayer materials and the multilayer was deposited onto the silicon wafer substrate and the reflectivity was measured by x-ray diffraction (XRD). The reflectivity of supermirror was about 20 % in 0.3 % of bandwidth. 8keV Cu target x-ray tube source was used in x-ray imaging experiments and the magnification of 1x and 2x x-ray images were obtained.

Colloidal Synthesis and Thermoelectric Properties of CuFeSe2 Nanocrystals

PubMed Central

Zhang, Bing-Qian; Zuo, Yong; Chen, Jing-Shuai; Niu, He-Lin; Mao, Chang-Jie

2017-01-01

Copper-based chalcogenides that contain abundant, low-cost and environmentally-friendly elements, are excellent materials for numerous energy conversion applications, such as photocatalysis, photovoltaics, photoelectricity and thermoelectrics (TE). Here, we present a high-yield and upscalable colloidal synthesis route for the production of monodisperse ternary I-III-VI2 chalcogenides nanocrystals (NCs), particularly stannite CuFeSe2, with uniform shape and narrow size distributions by using selenium powder as the anion precursor and CuCl2·2H2O and FeCl3 as the cationic precursors. The composition, the state of valence, size and morphology of the CuFeSe2 materials were examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM), respectively. Furthermore, the TE properties characterization of these dense nanomaterials compacted from monodisperse CuFeSe2 NCs by hot press at 623 K were preliminarily studied after ligand removal by means of hydrazine and hexane solution. The TE performances of the sintered CuFeSe2 pellets were characterized in the temperature range from room temperature to 653 K. Finally, the dimensionless TE figure of merit (ZT) of this Earth-abundant and intrinsic p-type CuFeSe2 NCs is significantly increased to 0.22 at 653 K in this work, which is demonstrated to show a promising TE materialand makes it a possible p-type candidate for medium-temperature TE applications. PMID:29278381

Optical, electrical and ferromagnetic studies of ZnO:Fe diluted magnetic semiconductor nanoparticles for spintronic applications.

PubMed

Elilarassi, R; Chandrasekaran, G

2017-11-05

In the present investigation, diluted magnetic semiconductor (Zn 1-x Fe x O) nanoparticles with different doping concentrations (x=0, 0.02, 0.04, 0.06, and 0.08) were successfully synthesized by sol-gel auto-combustion method. The crystal structure, morphology, optical, electrical and magnetic properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis using x-rays (EDAX), ultraviolet-visible spectrophotometer, fluorescence spectroscope (FS), vibrating sample magnetometer (VSM) and broad band dielectric spectrometer (BDS). XRD results reveal that all the samples possess hexagonal wurtzite crystal structure with good crystalline quality. The absence of impurity phases divulge that Fe ions are well incorporated into the ZnO crystal lattice. The substitutional incorporation of Fe 3+ at Zn sites is reflected in optical absorption spectra of the samples. Flouorescence spectra of the samples show a strong near-band edge related UV emission as well as defect related visible emissions. The semiconducting behavior of the samples has been confirmed through electrical conductivity measurements. Magnetic measurements indicated that all the samples possess ferromagnetism at room temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and physical properties of polycrystalline (Bi1-xPbx)2Sr2Ca2Cu3Oy high T c superconductors

NASA Astrophysics Data System (ADS)

Awan, M. S.; Maqsood, M.; Mirza, S. A.; Yousaf, M.; Maqsood, A.

1995-02-01

(Bi1-xPbx:)2Sr2Ca2Cu3Oy ( x = 0.3) high critical transition temperature ( T c) superconductors are synthesized by the solid-state reaction method in polycrystalline form. X-ray diffraction (XRD) studies, direct current (dc) electrical resistivity measurements, scanning electron microscopic (SEM) studies, critical current density measurements, and zero-field alternating current (ac) susceptibility measurements are performed to investigate the physical changes, structural changes, and magnetic behavior of the superconducting samples. X-ray diffraction studies show that a high T c phase exists with orthorhombic symmetry in the specimen. According to the XRD data, the lattice parameters of the high T c phase were determined as a = 0.537(1) nm, b = 0.539(1) nm, and c = 3.70(1) nm. The compound exhibits a superconducting transition at 106 ±1 K for zero resistance. The ac susceptibility measurements in zero field confirm the dc electrical resistivity results; hence both support the XRD results. The particle size and structural changes as a function of the cold-pressing and aging effect are also reported.

Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO{sub 4}:Dy TL material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamarudin, Nadira; Abdullah, Wan Saffiey Wan; Dollah, Mohd Taufik

2014-09-03

This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO{sub 4}) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 μm in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO{sub 4} with average crystallite size of 74 nm with orthorhombic crystal system. Themore » TL behavior of produced CaSO{sub 4}:Dy was studied using a TLD reader after exposure to gamma ray by Co{sup 60} source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry.« less

Effect of heat treatment procedure on magnetic and magnetocaloric properties of Ni43Mn46In11 melt spun ribbons

NASA Astrophysics Data System (ADS)

Kaya, M.; Elerman, Y.; Dincer, I.

2018-07-01

The effect of heat treatment on the structural, magnetic and magnetocaloric properties of Ni43Mn46In11 melt-spun ribbons was systematically investigated using X-ray powder diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), magnetic force microscope (MFM) and magnetic measurements. From the XRD studies, tetragonal and cubic phases were detected at room temperature for as-spun, quenched and slow-cooled ribbons. Furthermore, it was observed, upon annealing martensite transition temperatures increased when compared to the as-spun ribbon. To avoid magnetic hysteresis losses in the vicinity of the structural transition region, the magnetic entropy changes-ΔS m of the investigated ribbons were evaluated from temperature-dependent magnetisation-M(T) curves on cooling for different applied magnetic fields. The maximum ΔS m value was found to be 6.79 J kg-1 K-1 for the quenched ribbon in the vicinity of structural transition region for a magnetic field change of 50 kOe.

Piper nigrum Leaf and Stem Assisted Green Synthesis of Silver Nanoparticles and Evaluation of Its Antibacterial Activity Against Agricultural Plant Pathogens

PubMed Central

Paulkumar, Kanniah; Gnanajobitha, Gnanadhas; Vanaja, Mahendran; Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Pandian, Kannaiyan; Annadurai, Gurusamy

2014-01-01

Utilization of biological materials in synthesis of nanoparticles is one of the hottest topics in modern nanoscience and nanotechnology. In the present investigation, the silver nanoparticles were synthesized by using the leaf and stem extract of Piper nigrum. The synthesized nanoparticle was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray analysis (EDAX), and Fourier Transform Infrared Spectroscopy (FTIR). The observation of the peak at 460 nm in the UV-vis spectra for leaf- and stem-synthesized silver nanoparticles reveals the reduction of silver metal ions into silver nanoparticles. Further, XRD analysis has been carried out to confirm the crystalline nature of the synthesized silver nanoparticles. The TEM images show that the leaf- and stem-synthesized silver nanoparticles were within the size of about 7–50 nm and 9–30 nm, respectively. The FTIR analysis was performed to identify the possible functional groups involved in the synthesis of silver nanoparticles. Further, the antibacterial activity of the green-synthesized silver nanoparticles was examined against agricultural plant pathogens. The antibacterial property of silver nanoparticles is a beneficial application in the field of agricultural nanotechnology. PMID:24558336

Yttria-Stabilized Zirconia Ceramic Deposition on SS430 Ferritic Steel Grown by PLD - Pulsed Laser Deposition Method

NASA Astrophysics Data System (ADS)

Khalid Rivai, Abu; Mardiyanto; Agusutrisno; Suharyadi, Edi

2017-01-01

Development of high temperature materials are one of the key issues for the deployment of advanced nuclear reactors due to higher temperature operation. One of the candidate materials for that purpose is ceramic-coated ferritic steel that one of the functions is to be a thermal barrier coating (TBC). Thin films of YSZ (Ytrria-Stabilized Zirconia) ceramic have been deposited on a SS430 ferritic steel using Pulsed Laser Deposition (PLD) at Center For Science and Technology of Advanced Materials laboratory - National Nuclear Energy Agency of Indonesia (BATAN). The thin film was deposited with the chamber pressure range of 200-225 mTorr, the substrate temperature of 800oC, and the number of laser shots of 3×104, 6×104 and 9×104. Afterward, the samples were analyzed using Scanning Electron Microscope - Energy Dispersive X-ray Spectroscope (SEM-EDS), X-Ray Diffractometer (XRD), Atomic Force Microscope (AFM) and Vickers hardness tester. The results showed that the YSZ could homogeneously and sticky deposited on the surface of the ferritic steel. The surfaces were very smoothly formed with the surface roughness was in the range of 70 nm. Furthermore, thickness, composition of Zr4+ dan Y3+, the crystallinity, and hardness property was increased with the increasing the number of the shots.

Hard x-ray phase contrastmicroscopy - techniques and applications

NASA Astrophysics Data System (ADS)

Holzner, Christian

In 1918, Einstein provided the first description of the nature of the refractive index for X-rays, showing that phase contrast effects are significant. A century later, most x-ray microscopy and nearly all medical imaging remains based on absorption contrast, even though phase contrast offers orders of magnitude improvements in contrast and reduced radiation exposure at multi-keV x-ray energies. The work presented is concerned with developing practical and quantitative methods of phase contrast for x-ray microscopy. A theoretical framework for imaging in phase contrast is put forward; this is used to obtain quantitative images in a scanning microscope using a segmented detector, and to correct for artifacts in a commercial phase contrast x-ray nano-tomography system. The principle of reciprocity between scanning and full-field microscopes is then used to arrive at a novel solution: Zernike contrast in a scanning microscope. These approaches are compared on a theoretical and experimental basis in direct connection with applications using multi-keV x-ray microscopes at the Advanced Photon Source at Argonne National Laboratory. Phase contrast provides the best means to image mass and ultrastructure of light elements that mainly constitute biological matter, while stimulated x-ray fluorescence provides high sensitivity for studies of the distribution of heavier trace elements, such as metals. These approaches are combined in a complementary way to yield quantitative maps of elemental concentration from 2D images, with elements placed in their ultrastructural context. The combination of x-ray fluorescence and phase contrast poses an ideal match for routine, high resolution tomographic imaging of biological samples in the future. The presented techniques and demonstration experiments will help pave the way for this development.

Investigation on growth, structural, optical, electrical and X-ray sensing properties of chemically deposited zinc bismuth sulfide (ZnxBi2‑xS3) thin films

NASA Astrophysics Data System (ADS)

Sabarish, R.; Suriyanarayanan, N.; Kalita, J. M.; Sarma, M. P.; Wary, G.

2018-05-01

In the present work, ZnxBi2‑xS3 films were synthesized (x = 0.2 M) by a chemical bath deposition (CBD) technique at different bath temperatures (60 °C, 70 °C and 80 °C). The role of bath temperature on the formation of the films has been examined. The crystalline nature, structural parameters and surface morphology of the films were ascertained using x-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDS) respectively. These studies confirmed the formation of crystalline Zn0.2Bi1.8S3 films with uniform distribution of homogenous grains. The characterization results revealed that the film deposited at 70 °C has the good crystalline quality than the films deposited at 60 and 80 °C. Further, the optical absorption spectra showed that the bandgap (E g ) of the film deposited at 70 °C was about 2.39 eV which was found to be less than the same film deposited at 60 and 80 °C. The Current-Voltage (I-V) characteristics of all the films were measured under dark condition. This showed that the electrical conductivity of the film deposited at 70 °C was 1.61 × 10‑5 S cm‑1 which is ten times higher than other films. Further, the I-V characteristics of the film deposited at 70 °C was studied under x-ray radiation. The current under the x-ray radiation was significantly higher compared to the dark current. The x-ray detection sensitivity of the film was found to be maximum at 0.7 V and gradually decreases with increase of bias voltage. This analysis reveals that the film deposited at 70 °C can be used as an x-ray sensor.

SLAC All Access: X-ray Microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Johanna; Liu, Yijin

2012-08-14

SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

SLAC All Access: X-ray Microscope

ScienceCinema

Nelson, Johanna; Liu, Yijin

2018-01-16

SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

High resolution projection X-ray microscope equipped with fluorescent X-ray analyzer and its applications

NASA Astrophysics Data System (ADS)

Minami, K.; Saito, Y.; Kai, H.; Shirota, K.; Yada, K.

2009-09-01

We have newly developed an open type fine-focus X-ray tube "TX-510" to realize a spatial resolution of 50nm and to radiate low energy characteristic X-rays for giving high absorption contrast to images of microscopic organisms. The "TX-510" employs a ZrO/W(100) Schottky emitter and an "In-Lens Field Emission Gun". The key points of the improvements are (1) reduced spherical aberration coefficient of magnetic objective lens, (2) easy and accurate focusing, (3) newly designed astigmatism compensator, (4) segmented thin film target for interchanging the target materials by electron beam shift and (5) fluorescent X-ray analysis system.

Synthesis, crystal structure and characterization of a new organic-inorganic hybrid material 4-(ammonium methyl) pipyridinium hexachloro stanate (II) trihydrate

NASA Astrophysics Data System (ADS)

Lassoued, Mohamed Saber; Abdelbaky, Mohammed S. M.; Lassoued, Abdelmajid; Ammar, Salah; Gadri, Abdellatif; Ben Salah, Abdelhamid; García-Granda, Santiago

2018-03-01

The present paper undertakes the study of (C6H16N2) SnCl6·3H2O which is a new hybrid compound. It was prepared and characterized by single crystal X-ray diffraction, X-ray powder, Hirshfeld surface, Spectroscopy measurement, thermal study and photoluminescence properties. The single crystal X-ray diffraction studies revealed that the compound crystallizes in monoclinic Cc space group with cell parameters a = 8.3309(9) Å, b = 22.956(2) Å, c = 9.8381(9) Å, β = 101.334(9) ° and Z = 4. The atomic arrangement shows an alternation of organic and inorganic entities. The cohesion between these entities is performed via Nsbnd H⋯Cl, Nsbnd H⋯O, Osbnd H⋯Cl and Osbnd H⋯O hydrogen bonding to form a three-dimensional network. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D finger plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. The X-ray powder is in agreement with the X-ray structure. Scanning electron microscope (SEM) was carried out. Furthermore, the room temperature infrared (IR) spectrum of the title compound was recorded and analyzed on the basis of data found in the literature. Solid state 13C NMR spectrum shows four signals, confirming the solid state structure determined by X-ray diffraction. Besides, the thermal analysis studies were performed, but no phase transition was found in the temperature range between 30 and 450 °C. The optical and PL properties of the compound were investigated in the solid state at room temperature and exhibited three bands at 348 and 401 cm-1 and a strong fluorescence at 480 nm.

Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

NASA Astrophysics Data System (ADS)

Liu, Min; Zheng, Junyi; Lu, Yanling; Li, Zhijun; Zou, Yang; Yu, Xiaohan; Zhou, Xingtai

2013-09-01

Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 °C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (μ-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from μ-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 °C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys.

Electrodeposition of Ni and CeO₂/Ni Nanotubes for Hydrogen Evolution Reaction Electrode.

PubMed

Du, Xiaoqing; Yang, Yumeng; Yi, Chenxi; Chen, Yu; Cai, Chao; Zhang, Zhao

2018-07-01

Ni NTs and CeO2-Ni nanotubes (NTs) have been prepared by galvanostatic electrodeposition in anodic aluminum oxide (AAO) Templates. Scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopic (EDS) and X-ray Diffraction (XRD) are used to characterize the prepared NTs. The results showed that the preparation process of CeO2-Ni NTs was accompanied by the formation of many new phases CeNix (x = 1, 2, 3.5 or 5) and preferential orientation crystal face of Ni in CeO2-Ni NTs is 〈111〉, which is different from that Ni 〈200〉 in Ni NTs. Then linear scan voltammetry (LSV) is applied to test the electrocatalytic activity for hydrogen revolution reaction (HER) of the two electrodes in 1 M NaCl aqueous solution and find that both of the two materials exhibited good performance. Finally, the kinetics analyses from the HER process showed that Tafel slope b was mainly dependent on phase composition and electric conductivity of the electrode, while j0 was mainly dependent on its real specific surface area.

Specimen Holder for Analytical Electron Microscopes

NASA Technical Reports Server (NTRS)

Clanton, U. S.; Isaacs, A. M.; Mackinnon, I.

1985-01-01

Reduces spectral contamination by spurious X-ray. Specimen holder made of compressed carbon, securely retains standard electron microscope grid (disk) 3 mm in diameter and absorbs backscattered electrons that otherwise generate spurious X-rays. Since holder inexpensive, dedicated to single specimen when numerous samples examined.

Investigations on the properties of NH4HCO3 filled natural rubber based magnetorheological elastomers (MREs)

NASA Astrophysics Data System (ADS)

Fan, Lili; Wang, Guoping; Wang, Wenju; Shi, Guanxin; Yang, Fufeng; Rui, Xiaoting

2018-04-01

Various anisotropic magnetorheological elastomers (MREs) were synthesized using the rubber mixing technique. Magnetic and temperature distributions of the experimental equipment and test instruments were analyzed by the ANSYS. NH4HCO3 was filled in the natural rubber matrix to modify properties of MREs. Microstructures and compositions of samples were studied by the scanning electron microscope (SEM), the energy dispersive x-ray spectroscopy (EDAX) analysis and x-ray powder diffraction (XRD). Via vibrating sample magnetometer (VSM) and density functional theory (DFT) method, the magnetic property of carbonyl iron (CI) was illuminated. The shear storage modulus and MR effect of MREs were investigated by the dynamic mechanical analyzer (DMA). It indicated that distributions of magnetic and temperature in the experimental and testing devices were uniform. Before vulcanization, CI particles were uniformly distributed in the matrix, while a CI chain structure was formed and embedded in the matrix after the vulcanization process. Moderate addition of NH4HCO3 accelerated the rubber vulcanization and enhanced the MR effect.

A multi-analytical approach for the characterization of wall painting materials on contemporary buildings

NASA Astrophysics Data System (ADS)

Magrini, Donata; Bracci, Susanna; Cantisani, Emma; Conti, Claudia; Rava, Antonio; Sansonetti, Antonio; Shank, Will; Colombini, MariaPerla

2017-02-01

Samples from Keith Haring's wall painting of the Necker Children Hospital in Paris were studied by a multi-analytical protocol. X-ray fluorescence (XRF), powder X-ray diffraction (XRDP), Electron microscope (SEM-EDS), Infrared and Raman spectroscopy (μ-FT-IR and μ-Raman) measurements were performed in order to characterize the materials and to identify the art technique used to produce this contemporary work. Materials from the mural suffered from severe detachments of materials and several fragments were found on the ground beneath. Some of these fragments, which were representative of the whole palette and stratigraphic sequence, were collected and studied. The fragments were sufficiently large to enable non-invasive measurements to be performed in order to characterize the materials. A comparison of the data of the techniques applied revealed that Haring's palette was composed of organic pigments such as Naphtol red, phthalocyanine blue and green and Hansa yellow, in accordance with those used previously by the artist in other painted murals.

One-Pot Synthesis of Hierarchical Flower-Like Pd-Cu Alloy Support on Graphene Towards Ethanol Oxidation

NASA Astrophysics Data System (ADS)

Zhang, Jingyi; Feng, Anni; Bai, Jie; Tan, Zhibing; Shao, Wenyao; Yang, Yang; Hong, Wenjing; Xiao, Zongyuan

2017-09-01

The synergetic effect of alloy and morphology of nanocatalysts play critical roles towards ethanol electrooxidation. In this work, we developed a novel electrocatalyst fabricated by one-pot synthesis of hierarchical flower-like palladium (Pd)-copper (Cu) alloy nanocatalysts supported on reduced graphene oxide (Pd-Cu(F)/RGO) for direct ethanol fuel cells. The structures of the catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). The as-synthesized Pd-Cu(F)/RGO nanocatalyst was found to exhibit higher electrocatalytic performances towards ethanol electrooxidation reaction in alkaline medium in contrast with RGO-supported Pd nanocatalyst and commercial Pd black catalyst in alkaline electrolyte, which could be attributed to the formation of alloy and the morphology of nanoparticles. The high performance of nanocatalyst reveals the great potential of the structure design of the supporting materials for the future fabrication of nanocatalysts.

One-Pot Synthesis of Hierarchical Flower-Like Pd-Cu Alloy Support on Graphene Towards Ethanol Oxidation.

PubMed

Zhang, Jingyi; Feng, Anni; Bai, Jie; Tan, Zhibing; Shao, Wenyao; Yang, Yang; Hong, Wenjing; Xiao, Zongyuan

2017-09-02

The synergetic effect of alloy and morphology of nanocatalysts play critical roles towards ethanol electrooxidation. In this work, we developed a novel electrocatalyst fabricated by one-pot synthesis of hierarchical flower-like palladium (Pd)-copper (Cu) alloy nanocatalysts supported on reduced graphene oxide (Pd-Cu (F) /RGO) for direct ethanol fuel cells. The structures of the catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). The as-synthesized Pd-Cu (F) /RGO nanocatalyst was found to exhibit higher electrocatalytic performances towards ethanol electrooxidation reaction in alkaline medium in contrast with RGO-supported Pd nanocatalyst and commercial Pd black catalyst in alkaline electrolyte, which could be attributed to the formation of alloy and the morphology of nanoparticles. The high performance of nanocatalyst reveals the great potential of the structure design of the supporting materials for the future fabrication of nanocatalysts.

Novel p-n heterojunction copper phosphide/cuprous oxide photocathode for solar hydrogen production.

PubMed

Chen, Ying-Chu; Chen, Zhong-Bo; Hsu, Yu-Kuei

2018-08-01

A Copper phosphide (Cu 3 P) micro-rod (MR) array, with coverage by an n-Cu 2 O thin layer by electrodeposition as a photocathode, has been directly fabricated on copper foil via simple electro-oxidation and phosphidation for photoelectrochemical (PEC) hydrogen production. The morphology, structure, and composition of the Cu 3 P/Cu 2 O heterostructure are systematically analyzed using a scanning electron microscope (SEM), X-ray diffraction and X-ray photoelectron spectra. The PEC measurements corroborate that the p-Cu 3 P/n-Cu 2 O heterostructural photocathode illustrates efficient charge separation and low charge transfer resistance to achieve the highest photocurrent of 430 μA cm -2 that is greater than other transition metal phosphide materials. In addition, a detailed energy diagram of the p-Cu 3 P/n-Cu 2 O heterostructure was investigated using Mott-Schottky analysis. Our study paves the way to explore phosphide-based materials in a new class for solar energy applications. Copyright © 2018 Elsevier Inc. All rights reserved.

Radioactive Cobalt(II) Removal from Aqueous Solutions Using a Reusable Nanocomposite: Kinetic, Isotherms, and Mechanistic Study

PubMed Central

Wang, Ximing; Chen, Zhangjing

2017-01-01

A lignocellulose/montmorillonite (LMT) nanocomposite was prepared as a reusable adsorbent for cobalt(II) ions, and characterized by nitrogen (N2) adsorption/desorption isotherm, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). LMT exhibited efficient adsorption of cobalt ions (Co(II)), and the adsorbed Co(II) was readily desorbed by nitric acid (HNO3). All parameters affecting the adsorption and/or desorption of Co(II), including initial Co(II) concentration, pH value, temperature, HNO3 concentration, and time, were optimized. The kinetic data analysis showed that the adsorption followed the pseudo-second-order kinetic model and fit well into the Langmuir isotherm equation. Notably, the nanocomposite can be used four times without significantly losing adsorbent capability. The Energy-Dispersive X-ray (EDX) and FTIR spectra analysis also revealed that the adsorption mechanism may be mainly a chemical adsorption dominated process. PMID:29186794

Cyclic oxidation behavior of plasma sprayed NiCrAlY/WC-Co/cenosphere coating

NASA Astrophysics Data System (ADS)

Mathapati, Mahantayya; Ramesh M., R.; Doddamani, Mrityunjay

2018-04-01

Components working at elevated temperature like boiler tubes of coal and gas fired power generation plants, blades of gas and steam turbines etc. experience degradation owing to oxidation. Oxidation resistance of such components can be increased by developing protective coatings. In the present investigation NiCrAlY-WC-Co/Cenosphere coating is deposited on MDN 321 steel substrate using plasma spray coating. Thermo cyclic oxidation behavior of coating and substrate is studied in static air at 600 °C for 20 cycles. The thermo gravimetric technique is used to approximate the kinetics of oxidation. X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray mapping techniques are used to characterize the oxidized samples. NiCrAlY-WC-Co/Cenosphere coating exhibited lower oxidation rate in comparison to MDN 321 steel substrate. The lower oxidation rate of coating is attributed to formation of Al2O3, Cr2O3, NiO and CoWO4 oxides on the outermost surface.

Investigations on the Behavior of HVOF and Cold Sprayed Ni-20Cr Coating on T22 Boiler Steel in Actual Boiler Environment

NASA Astrophysics Data System (ADS)

Bala, Niraj; Singh, Harpreet; Prakash, Satya; Karthikeyan, J.

2012-01-01

High temperature corrosion accompanied by erosion is a severe problem, which may result in premature failure of the boiler tubes. One countermeasure to overcome this problem is the use of thermal spray protective coatings. In the current investigation high velocity oxy-fuel (HVOF) and cold spray processes have been used to deposit commercial Ni-20Cr powder on T22 boiler steel. To evaluate the performance of the coatings in actual conditions the bare as well as the coated steels were subjected to cyclic exposures, in the superheater zone of a coal fired boiler for 15 cycles. The weight change and thickness loss data were used to establish kinetics of the erosion-corrosion. X-ray diffraction, surface and cross-sectional field emission scanning electron microscope/energy dispersive spectroscopy (FE-SEM/EDS) and x-ray mapping techniques were used to analyse the as-sprayed and corroded specimens. The HVOF sprayed coating performed better than its cold sprayed counterpart in actual boiler environment.

Preparation and characterization of dialdehyde starch by one-step acid hydrolysis and oxidation.

PubMed

Zuo, Yingfeng; Liu, Wenjie; Xiao, Junhua; Zhao, Xing; Zhu, Ying; Wu, Yiqiang

2017-10-01

Dialdehyde starch was prepared by one-step synthesis of acid hydrolysis and oxidation, using corn starch as the raw material, sodium periodate (NaIO 4 ) as the oxidant, and hydrochloric acid (HCl) as the acid solution. The prepared dialdehyde starch was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The results confirmed that oxidation occurred between the starch and NaIO 4 . The acid hydrolysis reaction reduced the molecular weight of starch and effectively improved the aldehyde group contents (92.7%). Scanning electron microscope (SEM) analysis indicated that the average particle size decreased after acid hydrolysis and oxidation reaction. X-ray diffraction (XRD) and thermal gravimetric analyzer (TGA) analysis demonstrated that the crystallinity of the obtained dialdehyde starch showed a downward trend and a decelerated thermal decomposition rate. The starch after acid hydrolysis and oxidation exhibited lower hot paste viscosity and higher reactivity. Copyright © 2017. Published by Elsevier B.V.

Fabrication and characterization of nano-gas sensor arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hassan, H. S., E-mail: hassan.shokry@gmail.com; Kashyout, A. B., E-mail: hady8@yahoo.com; Morsi, I., E-mail: drimanmorsi@yahoo.com

2015-03-30

A novel structures of Nanomaterials gas sensors array constructed using ZnO, and ZnO doped with Al via sol-gel technique. Two structure arrays are developed; the first one is a double sensor array based on doping with percentages of 1% and 5%. The second is a quadrature sensor array based on several doping ratios concentrations (0%, 1%, 5% and 10%). The morphological structures of prepared ZnO were revealed using scanning electron microscope (SEM). X-ray diffraction (XRD) patterns reveal a highly crystallized wurtzite structure and used for identifying phase structure and chemical state of both ZnO and ZnO doped with Al undermore » different preparation conditions and different doping ratios. Chemical composition of Al-doped ZnO nanopowders was performed using energy dispersive x-ray (EDS) analysis. The electrical characteristics of the sensor are determined by measuring the two terminal sensor’s output resistance for O{sub 2}, H{sub 2} and CO{sub 2} gases as a function of temperature.« less

Evaluation of dose dependent antimicrobial activity of self-assembled chitosan, nano silver and chitosan-nano silver composite against several pathogens.

PubMed

Tareq, Foysal Kabir; Fayzunnesa, Mst; Kabir, Md Shahariar; Nuzat, Musrat

2018-01-01

The aim of this investigation to preparation of silver nanoparticles organized chitosan nano polymer, which effective against microbial and pathogens, when apply to liquid medium and edible food products surface, will rescue the growth of microbes. Self-assembly approach used to synthesis of silver nanoparticles and silver nanoparticles organized chitosan nano polymer. Silver nanoparticles and silver nanoparticles organized chitosan nano polymer and film characterized using Ultra-violate visible spectrometer (UV-vis), X-ray diffraction (X-ray), and Scanning electronic microscope (SEM). The crystalline structured protein capped nano silver successfully synthesized at range of 12 nm-29 nm and organized into chitosan nano polymer. Antimicrobial ingredient in liquid medium and food product surface provide to rescue oxidative change and growth of microorganism to provide higher safety. The silver nanoparticles organized chitosan nano polymer caused the death of microorganism. The materials in nano scale synthesized successfully using self-assembly method, which showed good antimicrobial properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of oxidizer to fuel molar ratio on particle size and DC conductivity of CeO{sub 2} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harish, B. M.; Rajeeva, M. P.; Naveen, C. S.

2016-05-06

Cerium oxide nanoparticles were synthesized by solution combustion method with varying the oxidizer (cerium nitrate hexa hydrate) to fuel (Glycine) molar ratio. The prepared samples were characterized by UV-visible spectrometer, X-ray diffractometer (XRD), Scanning electron microscope (SEM) and Energy dispersive X-Ray analysis (EDAX). XRD pattern reveals the formation of cubic fluorite structure of CeO{sub 2}. It was observed that finest crystallites were found at extreme fuel-deficient condition and it is good enough to produce favorable powder characteristics. The average crystallite size was found to be 14.46 nm to 21.57 nm. The temperature dependent dc conductivity was carried out using Keithleymore » source meter between the temperature range from 300 K to 573 K. From this study it was found that the conductivity increases with increase of temperature due to semiconducting behavior of CeO{sub 2} and it decreases with particle size due to increase in the energy band gap.« less

Synthesis of BiOCl nanosheets with oxygen vacancies for the improved photocatalytic properties

NASA Astrophysics Data System (ADS)

Cai, Yujie; Li, Dongya; Sun, Jingyu; Chen, Mengdie; Li, Yirui; Zou, Zhongwei; Zhang, Hua; Xu, Haiming; Xia, Dongsheng

2018-05-01

The square-sharped BiOCl nanosheets with oxygen vacancies were successfully synthesized via a facile hydrothermal route using xylitol as surfactant. The as-prepared BiOCl samples were characterized by Powder X-ray Diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), UV-Vis diffuse reflectance spectra (DRS), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) and Electron spin resonance (ESR). The as-prepared samples were phase-pure with the width and the thickness were about 50-400 nm and 20-50 nm respectively. Besides, the photodegradation performances showed the BiOCl nanosheets with 0.1 g concentration of xylitol (BOC-1) had the best photocatalytic activity under visible light due to its special polycrystalline structure, grain boundary and an optimum concentration of oxygen vacancies. The h+ and radO2- were the two main active species during the photocatalytic process and the possible photocatalytic mechanism was proposed.

Pozzolanic Characterization Of Waste Rice Husk Ash (RHA) From Muar, Malaysia

NASA Astrophysics Data System (ADS)

Hadipramana, J.; Riza, F. V.; Rahman, I. A.; Loon, L. Y.; Adnan, S. H.; Zaidi, A. M. A.

2016-11-01

Investigation of Rice Husk Ash (RHA) thoroughly under controlled burning is regular issue to obtain result to produce the amorphous silica that has high pozzolanic reactivity characteristic. This paper offered an observation about characteristic of ground and un-ground of un-controlled burning temperature RHA that were taken from rice millings in Muar, Johor Malaysia. Such tests as X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Particle Size Analysis and Specific Area Surface, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron microscope (SEM) were conducted in this investigation to carry out the characteristic of RHA samples. The results show that the RHA was consist approximately 89.90% of silica and the RHA possessed the amorphous particle were dominant than its crystalline part. This proves that the RHA has a big potential as a pozzolanic material considering the silica content and porous structure. In addition, particle size analysis decides whether the pozzolanic reactivity can be increased by grinding process.

Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Janaki, A. Chinnammal; Sailatha, E.; Gunasekaran, S.

2015-06-01

The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity.

Structure and growth of the mesoscopic surfactant/silica thin films

NASA Astrophysics Data System (ADS)

Zhou, Linbo

1999-10-01

We report the study of the structure and the growth of the mesoscopic surfactant/silica thin films. We use X-ray diffraction coupled with Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), Transmission Electron Microscope (TEM) and light scattering techniques to study the structure, lattice strain and the drying effect of the thin films as well as the growth kinetics and mechanism. The surfactant/silica materials are synthesized using the supramolecular assemblies of the surfactant molecules to template the condensation of the inorganic species. The subsequent calcination yields the mesoporous silica materials, which have many application properties such as unusual electronic, optical, magnetic and elastic characteristics. The films are grown on mica, graphite and silicon substrates in an acidic CTAC (Cetyltrimethyl Ammonium Chloride)/TEOS (Tetraethyl Orthosilicate) solution and are found to consist of the hexagonally packed tubules. The substrate plays an important role in the epitaxial arrangement of the film. We use the light scattering and cryo TEM to study the micelle morphology and aggregation in the solution and use synchrotron radiation X-ray diffraction to study the growth of the film at the solid/liquid interfaces in-situ. An induction time is found followed by the growth of the film at a nonlinear growth rate. The induction time depends on the ratio of the concentrations of CTAC to TEOS in the high CTAC concentration regime. The growth kinetics and mechanism are elucidated in a context of a growth model. For the technological application, Micromolding in Capillaries (MIMIC) technique and the field guided growth are used to process the patterned mesoscopic surfactant/silica thin films and align the nanotubules into the desired orientation. X-ray diffraction characterization has been performed to study the structure and orientation of the thin films. The combined influence of the electric field and the confinement of the mold allows the synthesis of the surfactant/silica thin films with the controlled orientation.

Electrical properties of CZTS pellets made from microwave-processed powder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghediya, Prashant R., E-mail: prashantghediya@yahoo.co.in; Chaudhuri, Tapas K.

2015-06-24

Electrical properties of the kesterite copper zinc tin sulphide (CZTS) pellets in the temperature range from 300 K to 500 K are reported. The pellets are p-type with thermoelectric power (TEP) of + 175 µV/K. Electrical conductivity (σ) increases with the temperatures and is found to be due to thermionic emission (TE) over grain boundary (GB) barriers with activation energy of 170 meV. CZTS pellets are made from micropowders synthesized by microwave irradiation of precursor solution. Formation of kesterite CZTS is confirmed by X-ray diffraction (XRD) and Raman spectroscopy. Scanning Electron Microscope (SEM) shows that powder is micron sized spherical particles.

Micro-emulsion-assisted synthesis of ZnS nanospheres and their photocatalytic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Yao; He Xiaoyan; Cao Minhua

2008-11-03

ZnS nanospheres with rough surface were synthesized by using a micro-emulsion-assisted solvothemal process. The molar ratio of [water]/[surfactant] played an important role in controlling the size of the ZnS nanospheres. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), field emission-scanning electron microscope (FE-SEM), and selected area electron diffraction (SAED) were used for the characterization of the resulting ZnS nanospheres. A possible formation mechanism was proposed. These ZnS nanospheres exhibited a good photocatalytic activity for degradation of an aqueous p-nitrophenol solution and the total organic carbon (TOC) of the degradation product has also been investigated.

Correlation between impurity distribution and location of ferroelectric domain walls in Nd : Mg : LiNbO 3 single crystal

NASA Astrophysics Data System (ADS)

Naumova, I. I.; Evlanova, N. F.; Blokhin, S. A.; Lavrishchev, S. V.

1998-04-01

Using selective chemical etching, scanning electron microscope (SEM) and wave dispersive X-ray (WDX) microanalysis we showed that the ferroelectric domain walls coincide with the maxima and minima Nd-impurity modulation in a periodically poled Nd : Mg : LiNbO 3 crystal grown by the Czochralski method along the normal to the (0 1 1¯ 2) face. Asymmetric form of the Nd-modulation produces nonequal positive and negative domains for one period. Variations of instantaneous rate of growth were estimated for facet and nonfacet crystal region in the framework of Burton-Prim-Slichter theory.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Hazeem, Nabeel Z., E-mail: nabeelnano333@gmail.com; Ministry of Education, the General Directorate for Educational Anbar; Ahmed, Naser M.

In this work, we fabricated nanorods by applying an electric potential on poly (ethylene oxide) (PEO) and polyaniline (PANI) as a polymeric solution by electrospinning method. Testing was conducted on the samples by field emission scanning Electron microscope (FE-SEM), X-ray diffraction (XRD) and Photoluminescence. And the results showed the emergence of nanorods in the sample within glass substrate. Diameters of nanorods have ranged between (52.78-122.40)nm And a length of between (1.15 – 1.32)μm. The emergence of so the results are for the first time, never before was the fabrication of nanorods for polymers using the same method used in thismore » research.« less

Comparison of Antimicrobial Properties of Nano Quinolone with its Microscale Effects

NASA Astrophysics Data System (ADS)

Behbahani, G. Rezaie; Sadr, M. Hossaini; Nabipour, H.; Behbahani, H. Rezaei; Vahedpour, M.; Barzegar, L.

2013-06-01

Nano nalidixic acid was prepared by ultrasonic method in carbon tetrachloride. Nano nalidixic acid (quinolone antibiotic) was characterized by X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscope (SEM). The antibacterial activities of nano nalidixic acid were tested against microorganisms and compared with the microscale drug. The results show that nano nalidixic acid has good inhibitory properties against two Gram-positive species, Staphylococcus aureus and Bacillus subtilis. Nano nalidixic acid also showed good antifungal activity against Candida albicans. Nano nalidixic acid can be injected into the human body as a decontaminating agent to prevent the growth of harmful microorganisms more effectively than the micro-sized drug.

Synthesis of Calcite Nano Particles from Natural Limestone assisted with Ultrasonic Technique

NASA Astrophysics Data System (ADS)

Handayani, M.; Sulistiyono, E.; Firdiyono, F.; Fajariani, E. N.

2018-03-01

This article represents a precipitation method assisted with ultrasonic process to synthesize precipitated calcium carbonate nano particles from natural limestone. The synthesis of nanoparticles material of precipitated calcium carbonate from commercial calcium carbonate was done for comparison. The process was performed using ultrasonic waves at optimum condition, that is, at temperature of 80oC for 10 minutes with various amplitudes. Synthesized precipitated calcium carbonate nanoparticles were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Particle Size Analyzer (PSA). The result of PSA measurements showed that precipitated calcium carbonate nano particles was obtained with the average size of 109 nm.

Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

NASA Astrophysics Data System (ADS)

Li, Kun; Liu, Junyao; Lei, Ting; Xiao, Tao

2015-10-01

A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

Design and analysis of aspherical multilayer imaging X-ray microscope

NASA Technical Reports Server (NTRS)

Shealy, David L.; Jiang, WU; Hoover, Richard B.

1991-01-01

Spherical Schwarzschild microscopes for soft X-ray applications in microscopy and projection lithography employ two concentric spherical mirrors that are configured such that the third-order spherical aberration and coma are zero. Based on incoherent, sine-wave MTF calculations, the object-plane resolution of a magnification-factor-20 microscope is presently analyzed as a function of object height and numerical aperture of the primary for several spherical Schwarzschild, conic, and aspherical two-mirror microscope configurations.

Microscopy based studies on the interaction of bio-based silver nanoparticles with Bombyx mori Nuclear Polyhedrosis virus.

PubMed

Tamilselvan, Selvaraj; Ashokkumar, Thirunavukkarasu; Govindaraju, Kasivelu

2017-04-01

In the present investigation, silver nanoparticles (AgNPs) interactions with Bombyx mori Nuclear Polyhedrosis virus (BmNPV) were characterized using High-Resolution Scanning Electron Microscopy (HR-SEM), Energy Dispersive X-ray Analysis (EDAX), Transmission Electron Microscopy (TEM), Atomic Force Microcopy (AFM) and Confocal Microscope (CM). HR-SEM study reveals that the biosynthesized AgNPs have interacted with BmNPV and were found on the surface. TEM micrographs of normal and viral polyhedra treated with AgNPs showed that the nanoparticles were accumulated in the membrane and it was noted that some of the AgNPs successfully penetrated the membrane by reaching the capsid of BmNPV. AFM and confocal microscopy studies reveal that the disruption in the shell membrane tends to lose its stability due to exposure of AgNPs to BmNPV. Copyright © 2017 Elsevier B.V. All rights reserved.

[Spectral characteristics of decomposition of incorporated straw in compound polluted arid loess].

PubMed

Fan, Chun-Hui; Zhang, Ying-Chao; Xu, Ji-Ting; Wang, Jia-Hong

2014-04-01

The original loess from western China was used as soil sample, the spectral methods of scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), elemental analysis, Fourier transform infrared spectroscopy (FT-IR) and 13C nuclear magnetic resonance (13C NMR) were used to investigate the characteristics of decomposed straw and formed humic acids in compound polluted arid loess. The SEM micrographs show the variation from dense to decomposed surface, and finally to damaged structure, and the EDS data reveal the phenomenon of element transfer. The newly-formed humic acids are of low aromaticity, helpful for increasing the activity of organic matters in loess. The FTIR spectra in the whole process are similar, indicating the complexity of transformation dynamics of humic acids. The molecular structure of humic acids becomes simpler, shown from 13C NMR spectra. The spectral methods are useful for humic acids identification in loess region in straw incorporation process.

Self-repairing vanadium-zirconium composite conversion coating for aluminum alloys

NASA Astrophysics Data System (ADS)

Zhong, Xin; Wu, Xiaosong; Jia, Yuyu; Liu, Yali

2013-09-01

In this paper, new self-repairing vanadium-zirconium composite conversion coating was prepared and investigated by Electrochemical impedance spectra (EIS), Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. EIS results showed that V-Zr conversion coating with hydrogen peroxide modified (VZO) revealed an increasing corrosion resistance in corrosive media which meant a certain self-repairing effect. SEM comparison photos also disclosed that VZO treated with scratches was gradually ameliorated from the initial cracked configuration to fewer cracks and more fillers through an immersion of 3.5% NaCl solution. XPS results demonstrated that the content of vanadium on VZO increased and zirconium declined when immersed in the corrosive solution. This explained further that the self-repairing ability could be related to vanadium. From the above results, we inferred possible structures of VZO and proposed that self-repairing effect was achieved through a hydrolysis condensation polymerization process of vanadate in the localized corrosion area.

Effect of isovalent dopants on photodegradation ability of ZnS nanoparticles

NASA Astrophysics Data System (ADS)

Khaparde, Rohini; Acharya, Smita

2016-06-01

Isovalent (Mn, Cd, Cu, Co)-doped-ZnS nanoparticles having size vary in between 2 to 5 nm are synthesized by co-precipitation route. Their photocatalytic activity for decoloration of Cango Red and Malachite Green dyes is tested in visible radiation under natural conditions. Structural and morphological features of the samples are investigated by X-ray diffraction, Raman spectroscopy, Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and UVsbnd Vis spectrometer. Single phase zinc blende structure of as-synthesized undoped and doped-ZnS is confirmed by XRD and revealed by Rietveld fitting. SEM and TEM images show ultrafine nanoparticles having size in the range of 2 to 5 nm. UV-Vis absorption spectra exhibit blue shift in absorption edge of undoped and doped ZnS as compared to bulk counterpart. The photocatalytic activity as a function of dopant concentration and irradiation time is systematically studied. The rate of de-coloration of dyes is detected by UVsbnd Vis absorption spectroscopy and organic dye mineralization is confirmed by table of carbon (TOC) study. The photocatalytic activity of Mn-doped ZnS is highest amongst all dopants; however Co as a dopant is found to reduce photocatalytic activity than pure ZnS.

Precipitation Rate Investigation on synthesis of precipitated calcium carbonate

NASA Astrophysics Data System (ADS)

Sulistiyono, E.; Handayani, M.; Firdiyono, F.; Fajariani, E. N.

2018-03-01

Study on the formation of precipitated calcium carbonate from natural limestone Sukabumi with the influenced of various parameters such as precipitation rate, concentration of CaCl2 and amplitudes were investigated. We also investigated the result with the precipitated calcium carbonate from Merck (p.a) for comparison. The higher concentration of CaCl2 would give effect to the lower of the precipitation rate. It was observed that precipitation rate of calcium carbonate from limestone Sukabumi at concentration of 0.08 molar was 3.66 cm/minutes and showing the optimum condition, while the precipitation rate of calcium carbonate Merck at the concentration 0.08 molar was 3.53 cm/minutes. The characterization of precipitated calcium carbonate was done using X-ray fluorescence (XRF) and scanning electron microscope (SEM). The characterization using XRF showed that CaO content of precipitated calcium carbonate from natural limestone Sukabumi had high purity of 99.16%. The particle distribution using scanning electron microscope (SEM) showed that precipitated calcium carbonate from natural limestone Sukabumi revealed 1.79 µm – 11.46 µm, meanwhile the particle distribution of precipitated calcium carbonate Merck showed larger particles with the size of 3.22 µm – 10.68 µm.

Investigation of Structure and Property of Indian Cocos nucifera L. Fibre

NASA Astrophysics Data System (ADS)

Basu, Gautam; Mishra, Leena; Samanta, Ashis Kumar

2017-12-01

Structure and physico-mechanical properties of Cocos nucifera L. fibre from a specific agro-climatic region of India, was thoroughly studied. Fine structure of the fibre was examined by Fourier Transform Infra-Red (FTIR) spectroscopy, Thermo-Gravimetric Analysis (TGA), X-Ray Diffraction (XRD), component analysis, Scanning Electron Microscope (SEM) and optical microscope. SEM shows prominent longitudinal cracks and micro-pores on the surface. XRD shows a low degree of crystallinity (45%), bigger crystallite size, and even the presence of appreciable amount of non-cellulose matter. FTIR reveals presence of large quantities of hydroxyl, phenolic and aldehyde groups. Component and thermal analyses indicates presence of cellulose and lignin as major components. Physical parameters reveal that, fibres are highly variable in length (range 44-305 mm), and diameter (range 100-795 µm). Mechanical properties of the fibre viz. breaking tenacity, breaking extensibility, specific work of rupture, and coefficient of friction were measured. Microbial decomposition test under soil reveals excellent durability of coconut fibre which makes it appropriate for the application in geotextiles. Mass specific electrical resistance of 4 Ω-kg/m2 indicates its enhanced insulation as compared to the jute.

A laboratory 8 keV transmission full-field x-ray microscope with a polycapillary as condenser for bright and dark field imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baumbach, S., E-mail: baumbach@rheinahrcampus.de; Wilhein, T.; Kanngießer, B.

2015-08-15

This article introduces a laboratory setup of a transmission full-field x-ray microscope at 8 keV photon energy. The microscope operates in bright and dark field imaging mode with a maximum field of view of 50 μm. Since the illumination geometry determines whether the sample is illuminated homogeneously and moreover, if different imaging methods can be applied, the condenser optic is one of the most significant parts. With a new type of x-ray condenser, a polycapillary optic, we realized bright field imaging and for the first time dark field imaging at 8 keV photon energy in a laboratory setup. A detectormore » limited spatial resolution of 210 nm is measured on x-ray images of Siemens star test patterns.« less

A laboratory 8 keV transmission full-field x-ray microscope with a polycapillary as condenser for bright and dark field imaging.

PubMed

Baumbach, S; Kanngießer, B; Malzer, W; Stiel, H; Wilhein, T

2015-08-01

This article introduces a laboratory setup of a transmission full-field x-ray microscope at 8 keV photon energy. The microscope operates in bright and dark field imaging mode with a maximum field of view of 50 μm. Since the illumination geometry determines whether the sample is illuminated homogeneously and moreover, if different imaging methods can be applied, the condenser optic is one of the most significant parts. With a new type of x-ray condenser, a polycapillary optic, we realized bright field imaging and for the first time dark field imaging at 8 keV photon energy in a laboratory setup. A detector limited spatial resolution of 210 nm is measured on x-ray images of Siemens star test patterns.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-01-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

Iodine Vapor Staining for Atomic Number Contrast in Backscattered Electron and X-ray Imaging

PubMed Central

Boyde, Alan; Mccorkell, Fergus A; Taylor, Graham K; Bomphrey, Richard J; Doube, Michael

2014-01-01

Iodine imparts strong contrast to objects imaged with electrons and X-rays due to its high atomic number (53), and is widely used in liquid form as a microscopic stain and clinical contrast agent. We have developed a simple technique which exploits elemental iodine's sublimation-deposition state-change equilibrium to vapor stain specimens with iodine gas. Specimens are enclosed in a gas-tight container along with a small mass of solid I2. The bottle is left at ambient laboratory conditions while staining proceeds until empirically determined completion (typically days to weeks). We demonstrate the utility of iodine vapor staining by applying it to resin-embedded tissue blocks and whole locusts and imaging them with backscattered electron scanning electron microscopy (BSE SEM) or X-ray microtomography (XMT). Contrast is comparable to that achieved with liquid staining but without the consequent tissue shrinkage, stain pooling, or uneven coverage artefacts associated with immersing the specimen in iodine solutions. Unmineralized tissue histology can be read in BSE SEM images with good discrimination between tissue components. Organs within the locust head are readily distinguished in XMT images with particularly useful contrast in the chitin exoskeleton, muscle and nerves. Here, we have used iodine vapor staining for two imaging modalities in frequent use in our laboratories and on the specimen types with which we work. It is likely to be equally convenient for a wide range of specimens, and for other modalities which generate contrast from electron- and photon-sample interactions, such as transmission electron microscopy and light microscopy. Microsc. Res. Tech. 77:1044–1051, 2014. © 2014 The Authors. Microscopy Research Technique published by Wiley Periodocals, Inc. PMID:25219801

LaNi0.6Co0 4O3-δ dip-coated on Fe-Cr mesh as a composite cathode contact material on intermediate solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Morán-Ruiz, Aroa; Vidal, Karmele; Larrañaga, Aitor; Laguna-Bercero, Miguel Angel; Porras-Vázquez, Jose Manuel; Slater, Peter Raymond; Arriortua, María Isabel

2014-12-01

The feasibility of using Crofer22APU mesh dip coated with LaNi0.6Co0.4O3-δ (LNC) ceramic paste as a uniform contact layer on a Crofer22APU channeled interconnect was studied. The control of LNC dip coating thickness on Fe-Cr mesh was carried out by rheological measurements of the suspension. SEM cross-section of formed composite contact material showed good adherence between ceramic and metallic components. The measured area specific resistance (ASR) value at 800 °C was 0.46 ± 0.01 mΩ cm2, indicating low contact resistance itself. The long term stability of metallic/ceramic composite was also studied. The contact resistance, when composite contact material was adhered to channeled Crofer22APU interconnect, was 5.40 ± 0.01 mΩ cm2, which is a suitable value for the performance of IT-SOFC stack. The stability of the system after treating at 800 °C for 1000 h was characterized using X-ray Micro-Diffraction (XRMD), Scanning Electron Microscope equipped with an Energy Dispersive X-ray analyzer (SEM-EDX) and X-ray Photoelectron Spectroscopy (XPS) techniques. The oxidation rate of the alloy and Fe3O4 phase formation were enhanced on the channels of the interconnect. Thus, the formation of CrO3 (g) and CrO2(OH)2 (g) species was accelerated on the composite surface under the channel. Through XRMD and XPS analysis the coexistence of two perovskite phases (initial LNC and Cr-perovskite) was observed.

Spatial investigation of some uranium minerals using nuclear microprobe

NASA Astrophysics Data System (ADS)

Valter, Anton A.; Knight, Kim B.; Eremenko, Gelij K.; Magilin, Dmitry V.; Ponomarov, Artem A.; Pisansky, Anatoly I.; Romanenko, Alexander V.; Ponomarev, Alexander G.

2018-06-01

In this work, several individual grains of uranium minerals—uraninite with high content of Ca, Ca-rich boltwoodite, growths of uranophane with β-uranophane, and weeksite—from different uranium deposits were studied by a scanning nuclear microprobe. Particle-induced X-ray emission technique provided by the microprobe (µ-PIXE) was carried out to obtain a concentration and 2D distribution of elements in these minerals. In addition, energy dispersive X-ray spectrometry (SEM-EDS) provided by a scanning electron microscope was used. The types of minerals were determined by X-ray diffraction methods. Results of this study improved the understanding of trace elemental composition of the uranium minerals depending on their origin. Obtained signatures could be linked then to the sample provenance. Such data are important for nuclear forensics to identify the ore types and even specific ore bodies, when only small samples may be available for analysis. In this study, the µ-PIXE technique was used for obtaining the 2D distribution of trace elements that are not commonly measured by SEM-EDS at the relevant concentrations. The detected levels and precisions of elements determination by µ-PIXE were also defined. Using µ-PIXE, several micro mineral inclusions such as phosphate with high level of V and Si were identified. The age of the uranium minerals was estimated due to a significant content of radiogenic Pb that provides an additional parameter for determination of the main attributive characteristics of the minerals. This work also showed that due to its high elemental sensitivity the nuclear microprobe can be a new analytical tool for creating a nuclear forensic database from the known uranium deposits and a subsequent analysis of the intercepted illicit materials.

The fabrication of visible light responsive Ag-SiO2 co-doped TiO2 thin films by the sol-gel method

NASA Astrophysics Data System (ADS)

Dam Le, Duy; Dung Dang, Thi My; Thang Chau, Vinh; Chien Dang, Mau

2010-03-01

In this study we have successfully deposited Ag-SiO2 co-doped TiO2 thin films on glass substrates by the sol-gel method. After being coated by a dip coating method, the film was transparent, smooth and had strong adhesion on the glass surface. The deposited film was characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), a scanning electron microscope (SEM) and atomic force microscope (AFM) to investigate its crystallization, transmittance and surface structure. The antifogging ability is explained by the contact angle of water on the surface of the glass substrates under visible-light. The obtained results show that Ag-SiO2 co-doped TiO2 film has potential applications for self cleaning and anti-bacterial ceramic tiles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Rabindar K., E-mail: rkrksharma6@gmail.com; Reddy, G. B., E-mail: rkrksharma6@gmail.com

In this report, we synthesize vertically aligned molybdenum trioxide (α−MoO{sub 3}) nanoflakes (NFs) with high aspect ratio (height/thickness >15) on the cobalt coated glass substrates by the plasma assisted sublimation process, employing Mo metal strip as a sublimation source. The effect of substrate temperature, nature of substrate as well as the geometry of the sublimation source (Mo-strip) have been investigated on the morphological, structural and optical properties of the grown NFs, keeping plasma parameters as fixed. The surface morphology, crystalline structure and optical properties of MoO{sub 3} NFs have been studied systematically by using scanning electron microscope (SEM), transmission electronmore » microscope (TEM) with selected area electron diffraction (SAED), X-ray diffractometer, and IR- spectroscopy. The experimental observations endorse that the characteristics of MoO{sub 3} NFs are strongly depend on substrate temperature, substrate nature as well as geometry of Mo-strip. All the observed results are well in consonance with each other.« less

In vitro assessments on bacterial adhesion and corrosion performance of TiN coating on Ti6Al4V titanium alloy synthesized by multi-arc ion plating

NASA Astrophysics Data System (ADS)

Lin, Naiming; Huang, Xiaobo; Zhang, Xiangyu; Fan, Ailan; Qin, Lin; Tang, Bin

2012-07-01

TiN coating was synthesized on Ti6Al4V titanium alloy surface by multi-arc ion plating (MIP) technique. Surface morphology, cross sectional microstructure, elemental distributions and phase compositions of the obtained coating were analyzed by means of scanning electron microscope (SEM), optical microscope (OM), glow discharge optical emission spectroscope (GDOES) and X-ray diffraction (XRD). Bacterial adhesion and corrosion performance of Ti6Al4V and the TiN coating were assessed via in vitro bacterial adhesion tests and corrosion experiments, respectively. The results indicated that continuous and compact coating which was built up by pure TiN with a typical columnar crystal structure has reached a thickness of 1.5 μm. This TiN coating could significantly reduce the bacterial adhesion and enhance the corrosion resistance of Ti6Al4V substrate.

Bio-templated synthesis of highly ordered macro-mesoporous silica material for sustained drug delivery

NASA Astrophysics Data System (ADS)

Qu, Fengyu; Lin, Huiming; Wu, Xiang; Li, Xiaofeng; Qiu, Shilun; Zhu, Guangshan

2010-05-01

The bimodal porous structured silica materials consisting of macropores with the diameter of 5-20 μm and framework-like mesopores with the diameter of 4.7-6.0 nm were prepared using natural Manchurian ash and mango linin as macropored hard templates and P123 as mesopore soft templates, respectively. The macroporous structures of Manchurian ash and mango linin were replicated with the walls containing highly ordered mesoporous silica as well. As-synthesized dual porous silica was characterized by scanning electron microscope (SEM), powder X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption/desorption, fourier transform IR (FTIR) spectroscopy, and thermo-gravimetric analyzer (TGA). Ibuprofen (Ibu) was employed as a model drug and the release profiles showed that the dual porous material had a sustained drug delivery capability. And such highly ordered dual pore silica materials may have potential applications for bimolecular adsorption/separation and tissue repairing.

Bioactivity of calcium phosphate bioceramic coating fabricated by laser cladding

NASA Astrophysics Data System (ADS)

Zhu, Yizhi; Liu, Qibin; Xu, Peng; Li, Long; Jiang, Haibing; Bai, Yang

2016-05-01

There were always strong expectations for suitable biomaterials used for bone regeneration. In this study, to improve the biocompatiblity of titanium alloy, calcium phosphate bioceramic coating was obtained by laser cladding technology. The microstructure, phases, bioactivity, cell differentiation, morphology and resorption lacunae were investigated by optical microscope (OM), x-ray diffraction (XRD), methyl thiazolyl tetrazolium (MTT) assay, tartrate-resistant acid phosphatase (TRAP) staining and scanning electronic microscope (SEM), respectively. The results show that bioceramic coating consists of three layers, which are a substrate, an alloyed layer and a ceramic layer. Bioactive phases of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) were found in ceramic coating. Osteoclast precursors have excellent proliferation on the bioceramic surface. The bioceramics coating could be digested by osteoclasts, which led to the resorption lacunae formed on its surface. It revealed that the gradient bioceramic coating has an excellent bioactivity.

Exfoliation of graphene sheets via high energy wet milling of graphite in 2-ethylhexanol and kerosene.

PubMed

Al-Sherbini, Al-Sayed; Bakr, Mona; Ghoneim, Iman; Saad, Mohamed

2017-05-01

Graphene sheets have been exfoliated from bulk graphite using high energy wet milling in two different solvents that were 2-ethylhexanol and kerosene. The milling process was performed for 60 h using a planetary ball mill. Morphological characteristics were investigated using scanning electron microscope (SEM) and transmission electron microscope (TEM). On the other hand, the structural characterization was performed using X-ray diffraction technique (XRD) and Raman spectrometry. The exfoliated graphene sheets have represented good morphological and structural characteristics with a valuable amount of defects and a good graphitic structure. The graphene sheets exfoliated in the presence of 2-ethylhexanol have represented many layers, large crystal size and low level of defects, while the graphene sheets exfoliated in the presence of kerosene have represented fewer number of layers, smaller crystal size and higher level of defects.

Microstructure-related properties of magnesium fluoride films at 193nm by oblique-angle deposition.

PubMed

Guo, Chun; Kong, Mingdong; Lin, Dawei; Liu, Cunding; Li, Bincheng

2013-01-14

Magnesium fluoride (MgF2) films deposited by resistive heating evaporation with oblique-angle deposition have been investigated in details. The optical and micro-structural properties of single-layer MgF2 films were characterized by UV-VIS and FTIR spectrophotometers, scanning electron microscope (SEM), atomic force microscope (AFM), and x-ray diffraction (XRD), respectively. The dependences of the optical and micro-structural parameters of the thin films on the deposition angle were analyzed. It was found that the MgF2 film in a columnar microstructure was negatively inhomogeneous of refractive index and polycrystalline. As the deposition angle increased, the optical loss, extinction coefficient, root-mean-square (rms) roughness, dislocation density and columnar angle of the MgF2 films increased, while the refractive index, packing density and grain size decreased. Furthermore, IR absorption of the MgF2 films depended on the columnar structured growth.

Thermal Conductivity on the Nanofluid of Graphene and Silver Nanoparticles Composite Material.

PubMed

Myekhlai, Munkhshur; Lee, Taejin; Baatar, Battsengel; Chung, Hanshik; Jeong, Hyomin

2016-02-01

The composite material consisted of graphene (GN) and silver nanoparticles (AgNPs) has been essential topic in science and industry due to its unique thermal, electrical and antibacterial proper- ties. However, there are scarcity studies based on their thermal properties of nanofluids. Therefore, GN-AgNPs composite material was synthesized using facile and environment friendly method and further nanofluids were prepared by ultrasonication in this study. The morphological and structural investigations were carried out using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD) as well as ultra violet (UV)-visible spectroscopy. Furthermore, thermal conductivity measurements were performed for as-prepared nanofluids. As a result of thermal conductivity study, GN-AgNPs composite material was considerably enhanced the thermal conductivity of base fluid (water) by to 6.59% for the nanofluid (0.2 wt% GN and 0.4 wt% AgNPs).

Structural and optical properties of Na-doped ZnO films

NASA Astrophysics Data System (ADS)

Akcan, D.; Gungor, A.; Arda, L.

2018-06-01

Zn1-xNaxO (x = 0.0-0.05) solutions have been synthesized by the sol-gel technique using Zinc acetate dihydrate and Sodium acetate which were dissolved into solvent and chelating agent. Na-doped ZnO nanoparticles were obtained from solutions to find phase and crystal structure. Na-doped ZnO films have been deposited onto glass substrate by using sol-gel dip coating system. The effects of dopant concentration on the structure, morphology, and optical properties of Na-doped ZnO thin films deposited on glass substrate are investigated. Characterization of Zn1-xNaxO nanoparticles and thin films are examined using differential thermal analysis (DTA)/thermogravimetric analysis (TGA), Scanning electron microscope (SEM) and X-Ray diffractometer (XRD). Optical properties of Zn1-xNaxO thin films were obtained by using PG Instruments UV-Vis-NIR spectrophotometer in 190-1100 nm range. The structure, morphology, and optical properties of thin films are presented.

Developments on a SEM-based X-ray tomography system: Stabilization scheme and performance evaluation

NASA Astrophysics Data System (ADS)

Gomes Perini, L. A.; Bleuet, P.; Filevich, J.; Parker, W.; Buijsse, B.; Kwakman, L. F. Tz.

2017-06-01

Recent improvements in a SEM-based X-ray tomography system are described. In this type of equipment, X-rays are generated through the interaction between a highly focused electron-beam and a geometrically confined anode target. Unwanted long-term drifts of the e-beam can lead to loss of X-ray flux or decrease of spatial resolution in images. To circumvent this issue, a closed-loop control using FFT-based image correlation is integrated to the acquisition routine, in order to provide an in-line drift correction. The X-ray detection system consists of a state-of-the-art scientific CMOS camera (indirect detection), featuring high quantum efficiency (˜60%) and low read-out noise (˜1.2 electrons). The system performance is evaluated in terms of resolution, detectability, and scanning times for applications covering three different scientific fields: microelectronics, technical textile, and material science.

Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope.

PubMed

Scholl, A; Marcus, M A; Doran, A; Nasiatka, J R; Young, A T; MacDowell, A A; Streubel, R; Kent, N; Feng, J; Wan, W; Padmore, H A

2018-05-01

Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast. Published by Elsevier B.V.

Microscale reconstruction of biogeochemical substrates using multimode X-ray tomography and scanning electron microscopy

NASA Astrophysics Data System (ADS)

Miller, M.; Miller, E.; Liu, J.; Lund, R. M.; McKinley, J. P.

2012-12-01

X-ray computed tomography (CT), scanning electron microscopy (SEM), electron microprobe analysis (EMP), and computational image analysis are mature technologies used in many disciplines. Cross-discipline combination of these imaging and image-analysis technologies is the focus of this research, which uses laboratory and light-source resources in an iterative approach. The objective is to produce images across length scales, taking advantage of instrumentation that is optimized for each scale, and to unify them into a single compositional reconstruction. Initially, CT images will be collected using both x-ray absorption and differential phase contrast modes. The imaged sample will then be physically sectioned and the exposed surfaces imaged and characterized via SEM/EMP. The voxel slice corresponding to the physical sample surface will be isolated computationally, and the volumetric data will be combined with two-dimensional SEM images along CT image planes. This registration step will take advantage of the similarity between the X-ray absorption (CT) and backscattered electron (SEM) coefficients (both proportional to average atomic number in the interrogated volume) as well as the images' mutual information. Elemental and solid-phase distributions on the exposed surfaces, co-registered with SEM images, will be mapped using EMP. The solid-phase distribution will be propagated into three-dimensional space using computational methods relying on the estimation of compositional distributions derived from the CT data. If necessary, solid-phase and pore-space boundaries will be resolved using X-ray differential phase contrast tomography, x-ray fluorescence tomography, and absorption-edge microtomography at a light-source facility. Computational methods will be developed to register and model images collected over varying scales and data types. Image resolution, physically and dynamically, is qualitatively different for the electron microscopy and CT methodologies. Routine CT images are resolved at 10-20 μm, while SEM images are resolved at 10-20 nm; grayscale values vary according to collection time and instrument sensitivity; and compositional sensitivities via EMP vary in interrogation volume and scale. We have so far successfully registered SEM imagery within a multimode tomographic volume and have used standard methods to isolate pore space within the volume. We are developing a three-dimensional solid-phase identification and registration method that is constrained by bulk-sample X-ray diffraction Rietveld refinements. The results of this project will prove useful in fields that require the fine-scale definition of solid-phase distributions and relationships, and could replace more inefficient methods for making these estimations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Li; Zhu, Zihua; Yu, Xiao-Ying

In this study, we report new results of in situ study of 5 nm goat anti-mouse IgG gold nanoparticles in a novel portable vacuum compatible microfluidic device using scanning electron microscope (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The unique feature of the liquid flow cell is that the detection window is open to the vacuum allowing direct probing of the liquid surface. The flow cell is composed of a silicon nitride (SiN) membrane and polydimethylsiloxane (PDMS), and it is fully compatible with vacuum operations for surface analysis. The aperture can be drilled through the 100 nm SiN membranemore » using a focused ion beam. Characteristic signals of the conjugated gold nanoparticles were successfully observed through the aperture by both energy-dispersive X-ray spectroscopy (EDX) in SEM and ToF-SIMS. Comparison was also made among wet samples, dry samples, and liquid sample in the flow cell using SEM/EDX. Stronger gold signal can be observed in our novel portable device by SEM/EDX compared with the wet or dry samples, respectively. Our results indicate that analyses of the nanoparticle components are better made in their native liquid environment. This is made possible using our unique microfluidic flow cell.« less

A simple method for detection of gunshot residue particles from hands, hair, face, and clothing using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX).

PubMed

Kage, S; Kudo, K; Kaizoji, A; Ryumoto, J; Ikeda, H; Ikeda, N

2001-07-01

We devised a simple and rapid method for detection of gunshot residue (GSR) particles, using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX) analysis. Experiments were done on samples containing GSR particles obtained from hands, hair, face, and clothing, using double-sided adhesive coated aluminum stubs (tape-lift method). SEM/WDX analyses for GSR were carried out in three steps: the first step was map analysis for barium (Ba) to search for GSR particles from lead styphnate primed ammunition, or tin (Sn) to search for GSR particles from mercury fulminate primed ammunition. The second step was determination of the location of GSR particles by X-ray imaging of Ba or Sn at a magnification of x 1000-2000 in the SEM, using data of map analysis, and the third step was identification of GSR particles, using WDX spectrometers. Analysis of samples from each primer of a stub took about 3 h. Practical applications were shown for utility of this method.

Microscopic and Metallurgical Aspects of the Space Shuttle Columbia Accident Investigation and Reconstruction

NASA Technical Reports Server (NTRS)

McDaniels, Steven J.

2004-01-01

The Space Shuttle Columbia was descending for a landing at the Kennedy Space Center (KSC) on February 1, 2003. Approximately 20 minutes prior to touchdown, the Columbia began disintegrating over the western United States; the majority of debris eventually impacted in eastern Texas and western Louisiana. A monumental effort eventually recovered approximately 84,000 pieces of debris, approximately 38% of the Orbiter's original dry weight. The debris was transported to KSC, where the items were catalogued and evaluated. Critical areas of interest, such as the left and right leading edge surfaces and the underside of the ship, were placed upon a grid to aid in the reconstruction. Items of interest included metallic structures, reinforced carbon-carbon composites, and ceramic heat insulation tiles. Many of the leading edge elements had re-solidified metallic deposits spattered on them. These deposits became known as slag and were one of the main focuses of the investigation. In order to help determine the sequence of events inside the left wing during the accident, the slag's composition, layering order, and directionality of deposition were studied. A myriad of analytical tests were performed in an attempt to ascertain the compositional and depositional characteristics of selected slag deposits, including the ordering of deposited layers within each individual slag deposit harvested. Initially, Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy (SEM/EDX) were performed to quickly characterize the overall composition of individual slag deposits: SEM utilizes a narrowlyfocused high-energy electron beam impinging upon a specimen. The incident beam excites and liberates lower energy secondary electrons, which are detected and analyzed, providing a visual representation of the sample's surface topography. EDX also relies on an incident electron beam, except an EDX unit measures X-ray energies generated by the impinging beam. Each element generates a unique X-ray signature; the EDX detector measures these discreet energies. EDX actually penetrates approximately 2 microns into the bulk of the sample. However, random examination of various portions of slag, coupled with the semiquantitative nature of the SEM/EDX analysis, did not yield convincingly pertinent data. Therefore, X-ray dot mapping was conducted, which provided more understandable data, both in terms of slag layering and composition. An X-ray dot map is generated by performing numerous EDX scans for individual elements, then compiling the scans in a visual representation. Eventually, specimens consisting of not only the slag, but of the adjacent RCC substrate as well were cross-sectioned. X-Ray dot mapping of the materialographicallymounted and -polished cross- sections provided a visual representation of both the layering sequence and compositional characteristics of the slag. Contemporaneously, Electron Spectroscopy for Chemical Analysis/X-Ray Photoelectron Spectroscopy (ESCA/XPS) and powdered X-Ray Diffraction (XRD) were performed to further characterize the deposits and to attempt to identify what, if any, compounds were present. The ESCA/XPS analysis allowed the analyst to "sputter" into the sample with an electron gun, aiding in the identification of the layering sequence. XPS uses photons, rather than electrons, which impinge upon the surface of the sample. XPS measures the electrons emitted from within the first 5 nm of the sample's surface. The XRD measures the scatter angles of incident X-rays; the angle and intensity of scatter depend upon the crystalline structure of the pulverized sample. XRD is considered a qualitative rather than quantitative technique. ESCA/XPS revealed that the final layer to deposit was predominantly carbonaceous. XRD was successful in identifying specific compounds, such as Al 2O3, Al and/or Al3 21SiO47, mullite (3(Al2)O3 -SiO2), and nickel-aluminides. Eventually, Electron MicroProbe Analysis (EMPA) was conducted on the marialographically-prepared cross- sections of selected slag deposits. Microprobe combines SEM and Wavelength Dispersive X-Ray Spectroscopy (WDS), and, like EDX, uses a narrowly-focused high-energy electron beam impinging upon a specimen to elicit, in the case of EPMA, characteristic X-rays with specific wavelengths. This quantitative, analytical tool proved the most useful in determining depositional layering and composition of the slag deposits. This information was utilized in verifying the location of the breach in the left leading edge of the wing of the Columbia.

Hybrid setup for micro- and nano-computed tomography in the hard X-ray range

NASA Astrophysics Data System (ADS)

Fella, Christian; Balles, Andreas; Hanke, Randolf; Last, Arndt; Zabler, Simon

2017-12-01

With increasing miniaturization in industry and medical technology, non-destructive testing techniques are an area of ever-increasing importance. In this framework, X-ray microscopy offers an efficient tool for the analysis, understanding, and quality assurance of microscopic samples, in particular as it allows reconstructing three-dimensional data sets of the whole sample's volume via computed tomography (CT). The following article describes a compact X-ray microscope in the hard X-ray regime around 9 keV, based on a highly brilliant liquid-metal-jet source. In comparison to commercially available instruments, it is a hybrid that works in two different modes. The first one is a micro-CT mode without optics, which uses a high-resolution detector to allow scans of samples in the millimeter range with a resolution of 1 μm. The second mode is a microscope, which contains an X-ray optical element to magnify the sample and allows resolving 150 nm features. Changing between the modes is possible without moving the sample. Thus, the instrument represents an important step towards establishing high-resolution laboratory-based multi-mode X-ray microscopy as a standard investigation method.

Green synthesis of iron nanoparticles by various tea extracts: comparative study of the reactivity.

PubMed

Huang, Lanlan; Weng, Xiulan; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

2014-09-15

Iron nanoparticles (Fe NPs) are often synthesized using sodium borohydride with aggregation, which is a high cost process and environmentally toxic. To address these issues, Fe NPs were synthesized using green methods based on tea extracts, including green, oolong and black teas. The best method for degrading malachite green (MG) was Fe NPs synthesized by green tea extracts because it contains a high concentration of caffeine/polyphenols which act as both reducing and capping agents in the synthesis of Fe NPs. These characteristics were confirmed by a scanning electron microscope (SEM), UV-visible (UV-vis) and specific surface area (BET). To understand the formation of Fe NPs using various tea extracts, the synthesized Fe NPs were characterized by SEM, X-ray energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD). What emerged were different sizes and concentrations of Fe NPs being synthesized by tea extracts, leading to various degradations of MG. Furthermore, kinetics for the degradation of MG using these Fe NPs fitted well to the pseudo first-order reaction kinetics model with more than 20 kJ/mol activation energy, suggesting a chemically diffusion-controlled reaction. The degradation mechanism using these Fe NPs included adsorption of MG to Fe NPs, oxidation of iron, and cleaving the bond that was connected to the benzene ring. Copyright © 2014 Elsevier B.V. All rights reserved.

Zircon Supported Copper Catalysts for the Steam Reforming of Methanol

NASA Astrophysics Data System (ADS)

Widiastri, M.; Fendy, Marsih, I. N.

2008-03-01

Steam reforming of methanol (SRM) is known as one of the most favorable catalytic processes for producing hydrogen. Current research on zirconia, ZrO2 supported copper catalyst revealed that CuO/ZrO2 as an active catalyst for the SRM. Zircon, ZrSiO4 is available from the by-product of tin mining. In the work presented here, the catalytic properties of CuO/ZrSiO4 with various copper oxide compositions ranging from 2.70% (catalyst I), 4.12% (catalyst II), and 7.12%-mass (catalyst III), synthesized by an incipient wetness impregnation technique, were investigated to methanol conversion, selectivity towards CO formation, and effect of ZnO addition (7.83%CuO/8.01%ZnO/ZrSiO4 = catalyst V). The catalytic activity was obtained using a fixed bed reactor and the zircon supported catalyst activity was compared to those of CuO/ZnO/Al2O3 catalyst (catalyst IV) and commercial Kujang LTSC catalyst. An X-ray powder diffraction (XRD) analysis was done to identify the abundant phases of the catalysts. The catalysts topography and particle diameter were measured with scanning electron microscopy (SEM) and composition of the catalysts was measured by SEM-EDX, scanning electron microscope-energy dispersive using X-ray analysis. The results of this research provide information on the possibility of using zircon (ZrSiO4) as solid support for SRM catalysts.

Role of Oxides and Porosity on High-Temperature Oxidation of Liquid-Fueled HVOF Thermal-Sprayed Ni50Cr Coatings

NASA Astrophysics Data System (ADS)

Song, B.; Bai, M.; Voisey, K. T.; Hussain, T.

2017-02-01

High chromium content in Ni50Cr thermally sprayed coatings can generate a dense and protective scale at the surface of coating. Thus, the Ni50Cr coating is widely used in high-temperature oxidation and corrosion applications. A commercially available gas atomized Ni50Cr powder was sprayed onto a power plant steel (ASME P92) using a liquid-fueled high velocity oxy-fuel thermal spray with three processing parameters in this study. Microstructure of as-sprayed coatings was examined using oxygen content analysis, mercury intrusion porosimetry, scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). Short-term air oxidation tests (4 h) of freestanding coatings (without boiler steel substrate) in a thermogravimetric analyzer at 700 °C were performed to obtain the kinetics of oxidation of the as-sprayed coating. Long-term air oxidation tests (100 h) of the coated substrates were performed at same temperature to obtain the oxidation products for further characterization in detail using SEM/EDX and XRD. In all samples, oxides of various morphologies developed on top of the Ni50Cr coatings. Cr2O3 was the main oxidation product on the surface of all three coatings. The coating with medium porosity and medium oxygen content has the best high-temperature oxidation performance in this study.

X-ray microscopy as an approach to increasing accuracy and efficiency of serial block-face imaging for correlated light and electron microscopy of biological specimens.

PubMed

Bushong, Eric A; Johnson, Donald D; Kim, Keun-Young; Terada, Masako; Hatori, Megumi; Peltier, Steven T; Panda, Satchidananda; Merkle, Arno; Ellisman, Mark H

2015-02-01

The recently developed three-dimensional electron microscopic (EM) method of serial block-face scanning electron microscopy (SBEM) has rapidly established itself as a powerful imaging approach. Volume EM imaging with this scanning electron microscopy (SEM) method requires intense staining of biological specimens with heavy metals to allow sufficient back-scatter electron signal and also to render specimens sufficiently conductive to control charging artifacts. These more extreme heavy metal staining protocols render specimens light opaque and make it much more difficult to track and identify regions of interest (ROIs) for the SBEM imaging process than for a typical thin section transmission electron microscopy correlative light and electron microscopy study. We present a strategy employing X-ray microscopy (XRM) both for tracking ROIs and for increasing the efficiency of the workflow used for typical projects undertaken with SBEM. XRM was found to reveal an impressive level of detail in tissue heavily stained for SBEM imaging, allowing for the identification of tissue landmarks that can be subsequently used to guide data collection in the SEM. Furthermore, specific labeling of individual cells using diaminobenzidine is detectable in XRM volumes. We demonstrate that tungsten carbide particles or upconverting nanophosphor particles can be used as fiducial markers to further increase the precision and efficiency of SBEM imaging.

X-ray Microscopy as an Approach to Increasing Accuracy and Efficiency of Serial Block-face Imaging for Correlated Light and Electron Microscopy of Biological Specimens

PubMed Central

Bushong, Eric A.; Johnson, Donald D.; Kim, Keun-Young; Terada, Masako; Hatori, Megumi; Peltier, Steven T.; Panda, Satchidananda; Merkle, Arno; Ellisman, Mark H.

2015-01-01

The recently developed three-dimensional electron microscopic (EM) method of serial block-face scanning electron microscopy (SBEM) has rapidly established itself as a powerful imaging approach. Volume EM imaging with this scanning electron microscopy (SEM) method requires intense staining of biological specimens with heavy metals to allow sufficient back-scatter electron signal and also to render specimens sufficiently conductive to control charging artifacts. These more extreme heavy metal staining protocols render specimens light opaque and make it much more difficult to track and identify regions of interest (ROIs) for the SBEM imaging process than for a typical thin section transmission electron microscopy correlative light and electron microscopy study. We present a strategy employing X-ray microscopy (XRM) both for tracking ROIs and for increasing the efficiency of the workflow used for typical projects undertaken with SBEM. XRM was found to reveal an impressive level of detail in tissue heavily stained for SBEM imaging, allowing for the identification of tissue landmarks that can be subsequently used to guide data collection in the SEM. Furthermore, specific labeling of individual cells using diaminobenzidine is detectable in XRM volumes. We demonstrate that tungsten carbide particles or upconverting nanophosphor particles can be used as fiducial markers to further increase the precision and efficiency of SBEM imaging. PMID:25392009

Effect of fluorine doping on highly transparent conductive spray deposited nanocrystalline tin oxide thin films

NASA Astrophysics Data System (ADS)

Moholkar, A. V.; Pawar, S. M.; Rajpure, K. Y.; Bhosale, C. H.; Kim, J. H.

2009-09-01

The undoped and fluorine doped thin films are synthesized by using cost-effective spray pyrolysis technique. The dependence of optical, structural and electrical properties of SnO 2 films, on the concentration of fluorine is reported. Optical absorption, X-ray diffraction, scanning electron microscope (SEM) and Hall effect studies have been performed on SnO 2:F (FTO) films coated on glass substrates. The film thickness varies from 800 to 1572 nm. X-ray diffraction pattern reveals the presence of cassiterite structure with (2 0 0) preferential orientation for FTO films. The crystallite size varies from 35 to 66 nm. SEM and AFM study reveals the surface of FTO to be made of nanocrystalline particles. The electrical study reveals that the films are degenerate and exhibit n-type electrical conductivity. The 20 wt% F doped film has a minimum resistivity of 3.8 × 10 -4 Ω cm, carrier density of 24.9 × 10 20 cm -3 and mobility of 6.59 cm 2 V -1 s -1. The sprayed FTO film having minimum resistance of 3.42 Ω/cm 2, highest figure of merit of 6.18 × 10 -2 Ω -1 at 550 nm and 96% IR reflectivity suggest, these films are useful as conducting layers in electrochromic and photovoltaic devices and also as the passive counter electrode.

Facile Synthesis of Efficient Antibacterial Agent as CoFe₂O₄/Ag Composite Material Against Both Gram-Negative Escherichia coli and Gram-Positive Bacillus subtilis Bacteria.

PubMed

Gankhuyag, Sukhbayar; Lee, Kyoung; Bae, Dong Sik

2018-09-01

We have suggested that a facile synthesis of CoFe2O4/Ag composite material as an antibacterial agent for substitution of a chlorination agent for microbial infected wastewater treatment. The CoFe2O4/Ag was synthesized by an impregnation method in assistance with trisodium citrate as a reducing agent. The as-prepared uncalcined CoFe2O4 (CFG), calcined CoFe2O4 (CFG600), and calcined CoFe2O4/Ag (CFG600/Ag) composites were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM) and Energy Dispersive X-ray (EDX) techniques. Antibacterial activities were also determined in liquid culture by measuring the minimum inhibitory concentrations (MIC) against Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) bacteria in vitro. Results showed that CFG600/Ag composites had an excellent antibacterial activity in comparison with CFG and CFG600 composites. The CFG600/Ag composites have completely inhibited the growth of both E. coli and B. subtilis bacteria from concentrations of more than 0.25 mg/ml. Furthermore, the FE-SEM study demonstrated the physical damage of bacteria when treated with CFG600/Ag composite material at a concentration of 0.10 mg/ml.

Effects of alpha-zirconium phosphate on thermal degradation and flame retardancy of transparent intumescent fire protective coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xing, Weiyi; Zhang, Ping; Song, Lei

2014-01-01

Graphical abstract: - Highlights: • A transparent intumescent fire protective coating was obtained by UV-cured technology. • OZrP could enhance the thermal stability and anti-oxidation of the coating. • OZrP could reduce the combustion properties of the coatings. - Abstract: Organophilic alpha-zirconium phosphate (OZrP) was used to improve the thermal and fire retardant behaviors of the phenyl di(acryloyloxyethyl)phosphate (PDHA)-triglycidyl isocyanurate acrylate (TGICA)-2-phenoxyethyl acrylate (PHEA) (PDHA-TGICA-PHEA) coating. The morphology of nanocomposite coating was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of OZrP on the flame retardancy, thermal stability, fireproofing time and char formation of the coatingsmore » was investigated by microscale combustion calorimeter (MCC), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), laser Raman spectroscopy (LRS) and scanning electric microscope (SEM). The results showed that by adding OZrP, the peak heat release rate and total heat of combustion were significantly reduced. The highest improvement was achieved with 0.5 wt% OZrP. XPS analysis indicated that the performance of anti-oxidation of the coating was improved with the addition of OZrP, and SEM images showed that a good synergistic effect was obtained through a ceramic-like layer produced by OZrP covered on the surface of char.« less

Electron Microscope Studies of Cadmium Mercury Telluride

NASA Astrophysics Data System (ADS)

Lyster, Martin

Available from UMI in association with The British Library. Requires signed TDF. Epitaxial layers of Cd_{x }Hg_{(1-x)}Te grown on various substrates by liquid phase epitaxy and metallo-organic vapour phase epitaxy have been studied using transmission and scanning electron microscopy, in a variety of contrast modes. Wavelength-dispersive X-ray microanalysis has been used to study interfaces in epitaxial specimens, and the results are used to derive diffusion coefficients for a range of values of x in Cd_ {x}Hg_{(1-x)} Te. Extensive use has been made of back-scattered electron contrast in the SEM as a means of compositional mapping, and defect structures are imaged by this technique. The back-scattered electron contrast at interfaces has been studied in detail and is modelled using the Monte Carlo approach. The modelling is combined with calculations and practical measurements of the probe size in the SEM instrument used in the work, to arrive at a quantitative explanation of this contrast. The SEM and scintillator detector used allow a spatial resolution of better than 1000A, but it is shown that improvements in this are possible with present technology. Scanning infra-red microscopy (SIRM) and high -resolution transmission electron microscopy (HREM) have been applied to the study of CdTe. SIRM images reveal information about Te precipitation, including particle size and density. HREM images provide results concerning dislocation structures in CdTe. Selected-area diffraction contrast TEM results are presented which illustrate the microstructure of LPE and MOVPE material; and TEM foil preparation techniques are discussed, including the choice of ion species for milling cross-sectional specimens. In view of the results obtained, suggestions are made for future work in this field.

Physicochemical characterization of raw materials and co-products from the titanium dioxide industry.

PubMed

Gázquez, M J; Bolívar, J P; García-Tenorio, R; Vaca, F

2009-07-30

The present study was conducted to characterize several raw materials and co-products from the titanium dioxide industry in relation to their elemental composition (major, minor and trace elements), granulometry, mineralogy, microscopic morphology and physical composition. The main objective was to gain basic information for the future potential application of these co-products in fields such as agriculture, construction, civil engineering, etc. Microscopic studies were performed by applying scanning electron microscopy with X-ray microanalysis (SEM-XRMA) while the mineralogical compositions were analysed by means of the X-ray diffraction (XRD) technique. The concentrations of major elements such as Na, Al, Si, Ca, Ti, Fe, S and K were determined by X-ray fluorescence (XRF), while heavy metals and other trace elements were determined by ICP-MS. The physicochemical characterization of the raw materials used in the titanium dioxide industry, in addition to the characterization of the co-products generated, has enabled the evaluation of the degree of fractionation of different elements and compounds between the different co-products, as well as the control of the possible variations in the physicochemical composition of the raw materials throughout the time and the study of the influence of these variations in the characteristics of the obtained co-products. As a main conclusion of our study, it is possible to indicate that the levels of the pollutant elements associated to the co-products analysed were, in general, within safe limits and, therefore, they could potentially be used in composites as fertilizers or for building materials in road construction, etc. Nevertheless, for the specific application of each of these co-products in agriculture, construction and civil engineering, additional studies need to be performed to evaluate their appropriateness for the proposed application, together with specific studies on their health and environmental impact.

Mechanical and structural characterizations of gamma- and alpha-alumina nanofibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vahtrus, Mikk; Umalas, Madis; Polyakov, Boris

2015-09-15

We investigate the applicability of alumina nanofibers as a potential reinforcement material in ceramic matrix compounds by comparing the mechanical properties of individual nanofibers before and after annealing at 1400 °C. Mechanical testing is performed inside a scanning electron microscope (SEM), which enables observation in real time of the deformation and fracture of the fibers under loading, thereby providing a close-up inspection of the freshly fractured area in vacuum. Improvement of both the Young's modulus and the breaking strength for annealed nanofibers is demonstrated. Mechanical testing is supplemented with the structural characterization of the fibers before and after annealing usingmore » SEM, transmission electron microscopy and X-ray diffraction methods. - Highlights: • Mechanical properties of individual alumina nanofibers were measured using in situ SEM cantilevered beam bending technique. • Improvement of mechanical properties of the alumina fibers after annealing at 1400 °C is demonstrated. • Formation of branched structures is demonstrated and their mechanical properties are studied. • XRD and electron microscopy were used for structural characterization of untreated and annealed nanofibers.« less

Is scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) quantitative?

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2013-01-01

Scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) is a widely applied elemental microanalysis method capable of identifying and quantifying all elements in the periodic table except H, He, and Li. By following the "k-ratio" (unknown/standard) measurement protocol development for electron-excited wavelength dispersive spectrometry (WDS), SEM/EDS can achieve accuracy and precision equivalent to WDS and at substantially lower electron dose, even when severe X-ray peak overlaps occur, provided sufficient counts are recorded. Achieving this level of performance is now much more practical with the advent of the high-throughput silicon drift detector energy dispersive X-ray spectrometer (SDD-EDS). However, three measurement issues continue to diminish the impact of SEM/EDS: (1) In the qualitative analysis (i.e., element identification) that must precede quantitative analysis, at least some current and many legacy software systems are vulnerable to occasional misidentification of major constituent peaks, with the frequency of misidentifications rising significantly for minor and trace constituents. (2) The use of standardless analysis, which is subject to much broader systematic errors, leads to quantitative results that, while useful, do not have sufficient accuracy to solve critical problems, e.g. determining the formula of a compound. (3) EDS spectrometers have such a large volume of acceptance that apparently credible spectra can be obtained from specimens with complex topography that introduce uncontrolled geometric factors that modify X-ray generation and propagation, resulting in very large systematic errors, often a factor of ten or more. © Wiley Periodicals, Inc.

High resolution tip-tilt positioning system for a next generation MLL-based x-ray microscope

DOE PAGES

Xu, Weihe; Schlossberger, Noah; Xu, Wei; ...

2017-11-15

Multilayer Laue lenses (MLLs) are x-ray focusing optics with the potential to focus hard x-rays down to a single nanometer level. In order to achieve point focus, an MLL microscope needs to have the capability to perform tip-tilt motion of MLL optics and to hold the angular position for an extended period of time. Here, we present a 2D tip-tilt system that can achieve an angular resolution of over 100 microdegree with a working range of 4°, by utilizing a combination of laser interferometer and mini retroreflector. The linear dimensions of the developed system are about 30 mm in allmore » directions, and the thermal dissipation of the system during operation is negligible. Compact design and high angular resolution make the developed system suitable for MLL optics alignment in the next generation of MLL-based x-ray microscopes.« less

X-ray Microscopic Characterization of Protein Crystals

NASA Technical Reports Server (NTRS)

Hu, Z. W.; Holmes, A.; Thomas, B.R.; Chernov, a. A.; Chu, Y. S.; Lai, B.

2004-01-01

The microscopic mapping of the variation in degree of perfection and in type of defects in entire protein crystals by x-rays may well be a prerequisite for better understanding causes of lattice imperfections, the growth history, and properties of protein crystals. However, x-ray microscopic characterization of bulk protein crystals, in the as-grown state, is frequently more challenging than that of small molecular crystals due to the experimental difficulties arising largely from the unique features possessed by protein crystals. In this presentation, we will illustrate ssme recent activities in employing coherence-based phase contrast x-ray imaging and high-angular-resolution diffraction techniques for mapping microdefects and the degree of perfection of protein crystals, and demonstrate a correlation between crystal perfection, diffraction phenomena., and crystallization conditions. The observed features and phenomena will be discussed in context to gain insight into the nature of defects, nucleation and growth, and the properties of protein crystals.

High resolution tip-tilt positioning system for a next generation MLL-based x-ray microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Weihe; Schlossberger, Noah; Xu, Wei

Multilayer Laue lenses (MLLs) are x-ray focusing optics with the potential to focus hard x-rays down to a single nanometer level. In order to achieve point focus, an MLL microscope needs to have the capability to perform tip-tilt motion of MLL optics and to hold the angular position for an extended period of time. Here, we present a 2D tip-tilt system that can achieve an angular resolution of over 100 microdegree with a working range of 4°, by utilizing a combination of laser interferometer and mini retroreflector. The linear dimensions of the developed system are about 30 mm in allmore » directions, and the thermal dissipation of the system during operation is negligible. Compact design and high angular resolution make the developed system suitable for MLL optics alignment in the next generation of MLL-based x-ray microscopes.« less

The nucleation and growth mechanism of Ni-Sn eutectic in a single crystal superalloy

NASA Astrophysics Data System (ADS)

Jiang, Weiguo; Wang, Li; Li, Xiangwei; Lou, Langhong

2017-12-01

The microstructure of single crystal superalloy with and without tin layer on the surface of as-cast and heat-treatment state was investigated by optical microscope (OM) and scanning electron microscopy (SEM). The composition of different regions on the surface was tested by energy dispersive X-ray (EDS). The reaction intermetallic compound (IMC) formed in the heat treatment process was confirmed by X-ray diffraction (XRD). The orientations of different microstructure in samples as heat treatment state were determined by electron back-scattering diffraction (EBSD) method. The porosity location in the interdendritic region was observed by X-ray computed tomography (XCT). The experiment results showed that the remained Sn on the surface of the superalloy reacted with Ni, and then formed Ni3Sn4 in the as-cast state. Sn enriched by diffusion along the porosity located in the interdendritic region and γ + γ‧ (contain a little of Sn) eutectic and Ni3Sn2 formed in single crystal superalloy during heat treatment, and the recalescence behaviors were found. Ni3Sn2 nucleated independently in the cooled liquid at the front of (γ + γ‧) (Sn) eutectic. The nucleation and growth mechanism of the eutectic and Ni3Sn2 IMC during heat treatment was discussed in the present paper.

Detection and distribution analysis of organosilicon compounds in wood by means of SEM-EDX and micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vetter, L. de; Cnudde, V.; Masschaele, B.

This article explores the potential of a scanning electron microscope with an energy dispersive X-ray spectrometer in combination with a new non-destructive 3D visualization technique, X-ray micro-computed tomography, as detection methods for siloxanes/silanes mixtures applied as wood preservatives. In order to have a higher contrast, bromine functional silane was added to the mixture. Scots pine and beech samples were dipped or impregnated with the mixture and subsequently scanned. Both silicon and bromine were easily detectable with both techniques. Dipped siloxanes/silanes covered the cell walls partly in beech and the lumen partly or completely in Scots pine. Impregnated siloxanes/silanes could bemore » found in the cell walls of both wood species. From the results, it can be concluded that, under the circumstances as described in the article, impregnation with a siloxane is necessary to have cell wall penetration. The combination of scanning electron microscopy, energy dispersive X-ray spectroscopy and micro-computed tomography can offer important information concerning the localization of certain products inside wood. While the last of these can monitor changes in 3D, the other two techniques can provide detailed 2D information. Both techniques are complementary and provide important extra information.« less

Pollen structure visualization using high-resolution laboratory-based hard X-ray tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Qiong; Gluch, Jürgen; Krüger, Peter

A laboratory-based X-ray microscope is used to investigate the 3D structure of unstained whole pollen grains. For the first time, high-resolution laboratory-based hard X-ray microscopy is applied to study pollen grains. Based on the efficient acquisition of statistically relevant information-rich images using Zernike phase contrast, both surface- and internal structures of pine pollen - including exine, intine and cellular structures - are clearly visualized. The specific volumes of these structures are calculated from the tomographic data. The systematic three-dimensional study of pollen grains provides morphological and structural information about taxonomic characters that are essential in palynology. Such studies have amore » direct impact on disciplines such as forestry, agriculture, horticulture, plant breeding and biodiversity. - Highlights: • The unstained whole pine pollen was visualized by high-resolution laboratory-based HXRM for the first time. • The comparison study of pollen grains by LM, SEM and high-resolution laboratory-based HXRM. • Phase contrast imaging provides significantly higher contrast of the raw images compared to absorption contrast imaging. • Surface and internal structure of the pine pollen including exine, intine and cellular structures are clearly visualized. • 3D volume data of unstained whole pollen grains are acquired and the specific volumes of the different layer are calculated.« less

Dark-field imaging with the scanning transmission x-ray microscope

NASA Astrophysics Data System (ADS)

Morrison, G. R.; Browne, M. T.

1992-01-01

The King's College London scanning transmission x-ray microscope in use on beam line 5U2 at the SRS, SERC Daresbury Laboratory, has been modified to allow dark-field images to be formed using only the x rays scattered by the specimen. Experiments have been performed with a number of different detector geometries, and this has confirmed that the strongest scattering arises from edges or thickness gradients in the specimen. Although the dark-field signal is only a small fraction of the normal transmitted bright-field signal, features can be revealed with high contrast, and it has proved possible to detect the presence of features that are below the resolution limit of the microscope.

Magnified hard x-ray microtomography: toward tomography with submicron resolution

NASA Astrophysics Data System (ADS)

Schroer, Christian G.; Benner, Boris; Guenzler, Til F.; Kuhlmann, Marion; Lengeler, Bruno; Rau, Christoph; Weitkamp, Timm; Snigirev, Anatoly A.; Snigireva, Irina

2002-01-01

Parabolic compound refractive lenses (PCRLs) are high quality imaging optics for hard x-rays that can be used as an objective lens in a new type of hard x-ray full field microscope. Using an aluminium PCRL, this new type of microscope has been shown to have a resolution of 350 nm. Further improvement of the resolution down to 50 nm can be expected using beryllium as a lens material. The large depth of field (several mm) of the microscope results in sharp projection images for samples that fit into the field of view of about 300 micrometers. This allows to combine magnified imaging with tomographic techniques. First results of magnified microtomography are shown. Contrast formation in the microscope and the consequences for tomographic reconstruction are discussed. An outlook on further developments is given.

Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro

2016-01-28

Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.

Application of SEM and EDX in studying biomineralization in plant tissues.

PubMed

He, Honghua; Kirilak, Yaowanuj

2014-01-01

This chapter describes protocols using formalin-acetic acid-alcohol (FAA) to fix plant tissues for studying biomineralization by means of scanning electron microscopy (SEM) and qualitative energy-dispersive X-ray microanalysis (EDX). Specimen preparation protocols for SEM and EDX mainly include fixation, dehydration, critical point drying (CPD), mounting, and coating. Gold-coated specimens are used for SEM imaging, while gold- and carbon-coated specimens are prepared for qualitative X-ray microanalyses separately to obtain complementary information on the elemental compositions of biominerals. During the specimen preparation procedure for SEM, some biominerals may be dislodged or scattered, making it difficult to determine their accurate locations, and light microscopy is used to complement SEM studies. Specimen preparation protocols for light microscopy generally include fixation, dehydration, infiltration and embedding with resin, microtome sectioning, and staining. In addition, microwave processing methods are adopted here to speed up the specimen preparation process for both SEM and light microscopy.

A combination of a SEM technique and X-ray microanalysis for studying the spore germination process of Clostridium tyrobutyricum.

PubMed

Bassi, Daniela; Cappa, Fabrizio; Cocconcelli, Pier Sandro

2009-06-01

Clostridium tyrobutyricum is an anaerobic bacterium responsible for late blowing defects during cheese ripening and it is of scientific interest for biological hydrogen production. A scanning electron microscopy (SEM) coating technique and X-ray microanalysis were developed to analyze the architecture and chemical composition of spores upon germination in response to environmental changes. In addition, we investigated the effects of different compounds on this process. Agents and environmental conditions inducing germination were characterized monitoring changes in optical density (OD). Among all tested conditions, the greatest drop in OD(625) (57.4%) was obtained when spores were incubated in l-alanine/l-lactate buffer, pH 4.6. In addition, a carbon-coating SEM technique and X-ray microanalysis were used to observe the architecture of spores and to examine calcium dipicolinate release. Conditions inducing C. tyrobutyricum spore germination were identified and SEM X-ray microanalysis clearly distinguished germinating from dormant spores. We confirmed that calcium dipicolinate release is one of the first events occurring. These microscopy methods could be considered sensitive tools for evaluating morphological and chemical changes in spores of C. tyrobutyricum during the initial phase of germination. Information gathered from this work may provide new data for further research on germination.

Characterization of As-polluted soils by laboratory X-ray-based techniques coupled with sequential extractions and electron microscopy: the case of Crocette gold mine in the Monte Rosa mining district (Italy).

PubMed

Allegretta, Ignazio; Porfido, Carlo; Martin, Maria; Barberis, Elisabetta; Terzano, Roberto; Spagnuolo, Matteo

2018-06-24

Arsenic concentration and distribution were studied by combining laboratory X-ray-based techniques (wavelength dispersive X-ray fluorescence (WDXRF), micro X-ray fluorescence (μXRF), and X-ray powder diffraction (XRPD)), field emission scanning electron microscopy equipped with microanalysis (FE-SEM-EDX), and sequential extraction procedure (SEP) coupled to total reflection X-ray fluorescence (TXRF) analysis. This approach was applied to three contaminated soils and one mine tailing collected near the gold extraction plant at the Crocette gold mine (Macugnaga, VB) in the Monte Rosa mining district (Piedmont, Italy). Arsenic (As) concentration, measured with WDXRF, ranged from 145 to 40,200 mg/kg. XRPD analysis evidenced the presence of jarosite and the absence of any As-bearing mineral, suggesting a high weathering grade and strong oxidative conditions. However, small domains of Fe arsenate were identified by combining μXRF with FE-SEM-EDX. SEP results revealed that As was mainly associated to amorphous Fe oxides/hydroxides or hydroxysulfates (50-80%) and the combination of XRPD and FE-SEM-EDX suggested that this phase could be attributed to schwertmannite. On the basis of the reported results, As is scarcely mobile, even if a consistent As fraction (1-3 g As/kg of soil) is still potentially mobilizable. In general, the proposed combination of laboratory X-ray techniques could be successfully employed to unravel environmental issues related to metal(loid) pollution in soil and sediments.

Effects of laser polishing on surface microstructure and corrosion resistance of additive manufactured CoCr alloys

NASA Astrophysics Data System (ADS)

Wang, W. J.; Yung, K. C.; Choy, H. S.; Xiao, T. Y.; Cai, Z. X.

2018-06-01

Laser polishing of 3D printed metal components has drawn great interest in view of its potential applications in the dental implant industries. In this study, corrosion resistance, surface composition and crystalline structure of CoCr alloys were investigated. The corrosion resistance, micromorphology, composition, phase transformations and crystalline structures of samples were characterized using an electrochemical analyzer, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The results indicate that high laser powers and low object distances within a certain range can facilitate the formation of complex oxide films, which exhibits high corrosion resistance. Further, object distances have a significant influence on cooling rates during the solidification of the melt pool in laser polishing, and fast cooling generates vast amounts of vacancies and defects, which result in the crystalline phase transformation from γ to ε. Consequently, the formed oxides play an important role in corrosion resistance on the outer layer, and inner layer with γ phase also helps keep the CoCr alloys in a stable structure with high resistant to corrosion. The two process parameters in laser polishing, laser power and object distances, are demonstrated as being important for controlling the surface microstructures and corrosion resistance of the additive manufactured CoCr alloy components.

Hydrothermal self-assembly of novel porous flower-like SnO2 architecture and its application in ethanol sensor

NASA Astrophysics Data System (ADS)

Jiang, X. H.; Ma, S. Y.; Sun, A. M.; Zhang, Z. M.; Jin, W. X.; Wang, T. T.; Li, W. Q.; Xu, X. L.; Luo, J.; Cheng, L.; Mao, Y. Z.; Zhang, M.

2015-11-01

Different morphologies of tin dioxide (SnO2) architectures were prepared by increasing reaction time (12, 18, 24 and 48 h) under a facile hydrothermal process and followed by calcination. The crystal structures and morphologies of the hierarchical architecture were characterized in detail by means of powder X-ray diffraction (XRD), energy dispersive X-ray detector (EDX), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the porous flower-like SnO2 architecture was obtained by 24 h hydrotherm treatment. Most importantly, the sensors based on porous flower-like SnO2 architecture exhibited perfect sensing performance toward ethanol with excellent selectivity, high response and fast response-recovery capability compared with other SnO2 nanoflowers for the same ethanol concentration at 300 °C. The response value was about 208 and the response-recovery time was around 8 and 7 s for 500 ppm ethanol, respectively. The enhancement in gas sensing properties was attributed to the unique structures, including the flower-like structure and porous feature, which provided more gas active center and diffusion pathways. The results indicated that porous flower-like SnO2 architecture was a potential candidate for fabricating effective ethanol sensor. Furthermore, the possible growth mechanism and the ethanol sensing mechanism of the architecture were discussed, too.

Dechlorination of disinfection by-product monochloroacetic acid in drinking water by nanoscale palladized iron bimetallic particle.

PubMed

Chen, Chao; Wang, Xiangyu; Chang, Ying; Liu, Huiling

2008-01-01

Nanoscale palladized iron (Pd/Fe) bimetallic particles were prepared by reductive deposition method. The particles were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM), transmission electron microscope (TEM), and Brunauer-Emmett-Teller-nitrogen (BET-N2) method. Data obtained from those methods indicated that nanoscale Pd/Fe bimetallic particles contained alpha-Fe0. Detected Pd to Fe ratio by weight (Pd/Fe ratio) was close to theoretical value. Spherical granules with diameter of 47 +/- 11.5 nm connected with one another to form chains and the chains composed nanoscale Pd/Fe bimetallic particles. Specific surface area of particles was 51 m2/g. The factors, such as species of reductants, Pd/Fe ratio, dose of nanoscale Pd/Fe bimetallic particles added into solutions, solution initial pH, and a variety of solvents were studied. Dechlorination effect of monochloroacetic acid by different reductants followed the trend: nanoscale Pd/Fe bimetallic particles of 0.182% Pd/Fe > nanoscale Fe > reductive Fe. When the Pd/Fe ratio was lower than 0.083%, increasing Pd/Fe ratio would increase dechlorination efficiency (DE) of MCAA. When the Pd/Fe ratio was higher than 0.083%, increasing Pd/Fe ratio caused a decrease in DE. Adding more nanoscale Pd/Fe bimetallic particles to solution would enhance DE. The DE of MCAA decreased as initial pH of solution increased.

Investigation of high temperature corrosion behavior on 304L austenite stainless steel in corrosive environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahri, M. I.; Othman, N. K.; Samsu, Z.

2014-09-03

In this work, 304L stainless steel samples were exposed at 700 °C for 10hrs in different corrosive environments; dry oxygen, molten salt, and molten salt + dry oxygen. The corrosion behavior of samples was analyzed using weight change measurement technique, optical microscope (OM) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX). The existence phases of corroded sample were determined using X-ray Diffraction (XRD). The lowest corrosion rate was recorded in dry oxygen while the highest was in molten salt + dry oxygen environments with the value of 0.0062 mg/cm{sup 2} and −13.5225 mg/cm{sup 2} respectively. The surfacemore » morphology of sample in presence of salt mixture showed scale spallation. Oxide scales of Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3} were the main phases developed and detected by XRD technique. Cr{sub 2}O{sub 3} was not developed in every sample as protective layers but chromate-rich oxide was developed. The cross-section analysis found the oxide scales were in porous, thick and non-adherent that would not an effective barrier to prevent from further degradation of alloy. EDX analysis also showed the Cr-element was low compared to Fe-element at the oxide scale region.« less

The effect of porosity on the mechanical properties of porous titanium scaffolds: comparative study on experimental and analytical values

NASA Astrophysics Data System (ADS)

Khodaei, Mohammad; Fathi, Mohammadhossein; Meratian, Mahmood; Savabi, Omid

2018-05-01

Reducing the elastic modulus and also improving biological fixation to the bone is possible by using porous scaffolds. In the present study, porous titanium scaffolds containing different porosities were fabricated using the space holder method. Pore distribution, formed phases and mechanical properties of titanium scaffolds were studied by Scanning Electron Microscope (SEM), x-ray diffraction (XRD) and cold compression test. Then the results of compression test were compared to the Gibson-Ashby model. Both experimentally measured and analytically calculated elastic modulus of porous titanium scaffolds decreased by porosity increment. The compliance between experimentally measured and analytically calculated elastic modulus of titanium scaffolds are also increased by porosity increment.

[Topography structure and flocculation mechanism of polymeric phosphate ferric sulfate (PPFS)].

PubMed

Zheng, Huai-li; Zhang, Hui-qin; Jiang, Shao-jie; Li, Fang; Jiao, Shi-jun; Fang, Hui-li

2011-05-01

Characteristics of polymeric phosphate ferric sulfate (PPFS) were investigated using FTIR (Fourier transform infrared spectrometer), XRD (X-ray diffraction) and SEM (scanning electron microscope) in the present study. The formed PPFS structure and morphology were stereo meshwork, which was clustered and close to coral reef, synthesis of high charge density, bioactive polyhydroxy and mixed polynuclear complex PPFS. The results showed that charge neutralization of PPFS had not played a decisive role in the coagulation beaker test and the zeta potential proved that PPFS was largely affected by bridging and netting sweep. Therefore, the coagulation mechanisms of PPFS were mainly composed of charge neutralization, adsorption bridging and netting sweep mechanisms.

ZnO nanoparticles based fiber optic gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narasimman, S.; Sivacoumar, R.; Alex, Z. C.

In this work, ZnO nanoparticles were synthesized by simple aqueous chemical route method. The synthesized ZnO nanoparticles were characterized by X-ray diffraction and scanning electron microscope. The sensitivity of the nanoparticles was studied for different gases like acetone, ammonia and ethanol in terms of variation in spectral light intensity. The XRD and SEM analysis confirms the formation of hexagonal wurtzite structure with the grain size of 11.2 nm. The small cladding region of the optical fiber was replaced with the synthesized nanoparticles. The light spectrum was recorded for different gas concentrations. The synthesized nanoparticles showed high sensitivity towards ammonia in lowmore » ppm level and acetone in high ppm level.« less

HA/Bioglass composite films deposited by pulsed laser with different substrate temperature

NASA Astrophysics Data System (ADS)

Wang, D. G.; Chen, C. Z.; Jin, Q. P.; Li, H. C.; Pan, Y. K.

2014-03-01

In this experiment, the HA/Bioglass composite films on Ti-6Al-4V were deposited by a pulsed laser at Ar atmosphere, and the influence of substrate temperature on the morphology, phase constitutions, bonding configurations and adhesive strength of the films was studied. The obtained films were characterized by an electron probe microanalyzer (EPMA), scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), scratch apparatus, and so on. The results show that the amount of the droplets, the crystallinity, and the critical load of the deposited films all increase with the increase of the substrate temperature; however, the substrate temperature has little influence on the functional groups of the films.

The Effects of ph on Structural and Optical Characterization of Iron Oxide Thin Films

NASA Astrophysics Data System (ADS)

Tezel, Fatma Meydaneri; Özdemir, Osman; Kariper, I. Afşin

In this study, the iron oxide thin films have been produced by chemical bath deposition (CBD) method as a function of pH onto amorphous glass substrates. The surface images of the films were investigated with scanning electron microscope (SEM). The crystal structures, orientation of crystallization, crystallite sizes, and dislocation density i.e. structural properties of the thin films were analyzed with X-ray diffraction (XRD). The optical band gap (Eg), optical transmission (T%), reflectivity (R%), absorption coefficient (α), refraction index (n), extinction coefficient (k) and dielectric constant (ɛ) of the thin films were investigated depending on pH, deposition time, solution temperature, substrate temperature, thickness of the films by UV-VIS spectrometer.

Solution combustion method for synthesis of nanostructured hydroxyapatite, fluorapatite and chlorapatite

NASA Astrophysics Data System (ADS)

Zhao, Junjie; Dong, Xiaochen; Bian, Mengmeng; Zhao, Junfeng; Zhang, Yao; Sun, Yue; Chen, JianHua; Wang, XuHong

2014-09-01

Hydroxyapatite (HAP), fluorapatite (Fap) and chlorapatite (Clap) were prepared by solution combustion method with further annealing at 800 °C. The characterization and structural features of the synthesized powders were evaluated by the powder X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques. Characterization results from XRD and Rietveld analysis revealed that OH- in the HAP lattice were gradually substituted with the increase of F- and Cl- content and totally substituted at the molar concentration of 0.28 and 0.6, respectively. The results from FI-IR have also confirmed the incorporation of substituted anions in the apatite structure.

Electrochemical properties of doped lithium titanate compounds and their performance in lithium rechargeable batteries

NASA Astrophysics Data System (ADS)

Shenouda, Atef Y.; Murali, K. R.

Several substituted titanates of formula Li 4- xMg xTi 5- xV xO 12 (0 ≤ x ≤ 1) were synthesized (and investigated) as anode materials in rechargeable lithium batteries. Five samples labeled as S1-S5 were calcined (fired) at 900 °C for 10 h in air, and slowly cooled to room temperature in a tube furnace. The structural properties of the synthesized products have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transmission infrared (FTIR). XRD explained that the crystal structures of all samples were monoclinic while S1 and S3 were hexagonal. The morphology of the crystal of S1 was spherical while the other samples were prismatic in shape. SEM investigations explained that S4 had larger grain size diameter of 15-16 μm in comparison with the other samples. S4 sample had the highest conductivity 2.452 × 10 -4 S cm -1. At a voltage plateau located at about 1.55 V (vs. Li +), S4 cell exhibited an initial specific discharge capacity of 198 mAh g -1. The results of cyclic voltammetry for Li 4- xMg xTi 5- xV xO 12 showed that the electrochemical reaction was based on Ti 4+/Ti 3+ redox couple at potential range from 1.5 to 1.7 V. There is a pair of reversible redox peaks corresponding to the process of Li + intercalation and de-intercalation in the Li-Ti-O oxides.

Correlative tomography at the cathode/electrolyte interfaces of solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Wankmüller, Florian; Szász, Julian; Joos, Jochen; Wilde, Virginia; Störmer, Heike; Gerthsen, Dagmar; Ivers-Tiffée, Ellen

2017-08-01

This paper introduces a correlative tomography technique. It visualizes the spatial organization of primary and secondary phases at the interface of La0.58Sr0.4Co0.2Fe0.8O3-δ cathode/10 mol% Gadolinia doped Ceria/8 mol% Yttria stabilized Zirconia electrolyte. It uses focused ion beam/scanning electron microscope tomography (FIB/SEM), and combines data sets from Everhart-Thornley and Inlens detector differentiating four primary and two secondary material phases. In addition, grayscale information is correlated to elemental distribution gained by energy dispersive X-ray spectroscopy in a scanning transmission electron microscope. Interdiffusion of GDC into YSZ and SrZrO3 as secondary phases depend (in both amount and spatial organization) on the varied co-sintering temperature of the GDC/YSZ electrolyte. The ion-blocking SrZrO3 forms a continuous layer on top of the temperature-dependent GDC/YSZ interdiffusion zone (ID) at and below a co-sintering temperature of 1200 °C; above it becomes intermittent. 2D FIB/SEM images of primary and secondary phases at 1100, 1200, 1300 and 1400 °C were combined with a 3D FIB/SEM reconstruction (1300 °C). This reveals that ;preferred; oxygen ion transport pathways from the LSCF cathode through GDC and the ID into the YSZ electrolyte only exist in samples sintered above 1200 °C. The applied correlative technique expands our understanding of this multiphase cathode/electrolyte interface region.

A mirror for lab-based quasi-monochromatic parallel x-rays

NASA Astrophysics Data System (ADS)

Nguyen, Thanhhai; Lu, Xun; Lee, Chang Jun; Jung, Jin-Ho; Jin, Gye-Hwan; Kim, Sung Youb; Jeon, Insu

2014-09-01

A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

Diffracting aperture based differential phase contrast for scanning X-ray microscopy.

PubMed

Kaulich, Burkhard; Polack, Francois; Neuhaeusler, Ulrich; Susini, Jean; di Fabrizio, Enzo; Wilhein, Thomas

2002-10-07

It is demonstrated that in a zone plate based scanning X-ray microscope, used to image low absorbing, heterogeneous matter at a mesoscopic scale, differential phase contrast (DPC) can be implemented without adding any additional optical component to the normal scheme of the microscope. The DPC mode is simply generated by an appropriate positioning and alignment of microscope apertures. Diffraction from the apertures produces a wave front with a non-uniform intensity. The signal recorded by a pinhole photo diode located in the intensity gradient is highly sensitive to phase changes introduced by the specimen to be recorded. The feasibility of this novel DPC technique was proven with the scanning X-ray microscope at the ID21 beamline of the European Synchrotron Radiation facility (ESRF) operated at 6 keV photon energy. We observe a differential phase contrast, similar to Nomarski's differential interference contrast for the light microscope, which results in a tremendous increase in image contrast of up to 20 % when imaging low absorbing specimen.

Nanoscale characterization of local structures and defects in photonic crystals using synchrotron-based transmission soft X-ray microscopy

PubMed Central

Nho, Hyun Woo; Kalegowda, Yogesh; Shin, Hyun-Joon; Yoon, Tae Hyun

2016-01-01

For the structural characterization of the polystyrene (PS)-based photonic crystals (PCs), fast and direct imaging capabilities of full field transmission X-ray microscopy (TXM) were demonstrated at soft X-ray energy. PS-based PCs were prepared on an O2-plasma treated Si3N4 window and their local structures and defects were investigated using this label-free TXM technique with an image acquisition speed of ~10 sec/frame and marginal radiation damage. Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components. Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated. This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties. PMID:27087141

Installation of Multiple Application X-ray Imaging Undulator Microscope (MAXIMUM) at ALS: Final report, 8/15/95-8/15/96

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-12-31

MAXIMUM is short for Multiple Application X-ray IMaging Undulator Microscope, a project started in 1988 by our group at the Synchrotron Radiation Center of the University of Wisconsin-Madison. It is a scanning x-ray photoemission microscope that uses a multilayer-coated Schwarzschild objective as the focusing element. It was designed primarily for materials science studies of lateral variations in surface chemistry. Suitable problems include: lateral inhomogeneities in Schottky barrier formation, heterojunction formation, patterned samples and devices, insulating samples. Any system which has interesting properties that are not uniform as a function of spatial dimension can potentially be studied with MAXIMUM. 6 figs.,more » 3 tabs.« less

Enhancement of bioactivity of titanium carbonitride nanocomposite thin films on steels with biosynthesized hydroxyapatite

PubMed Central

Thampi, VV Anusha; Dhandapani, P; Manivasagam, Geetha; Subramanian, B

2015-01-01

Thin films of titanium carbonitride (TiCN) were fabricated by DC magnetron sputtering on medical grade steel. The biocompatibility of the coating was further enhanced by growing hydroxyapatite crystals over the TiCN-coated substrates using biologically activated ammonia from synthetic urine. The coatings were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM)-energy dispersive spectroscopy, and Raman spectroscopy. The electrochemical behavior of the coatings was determined in simulated body fluid. In addition, hemocompatibility was assessed by monitoring the attachment of platelets on the coating using SEM. The wettability of the coatings was measured in order to correlate with biocompatibility results. Formation of a coating with granular morphology and the preferred orientation was confirmed by SEM and X-ray diffraction results. The hydroxyapatite coating led to a decrease in thrombogenicity, resulting in controlled blood clot formation, hence demonstrating the hemocompatibility of the coating. PMID:26491312

Enhancement of bioactivity of titanium carbonitride nanocomposite thin films on steels with biosynthesized hydroxyapatite.

PubMed

Thampi, V V Anusha; Dhandapani, P; Manivasagam, Geetha; Subramanian, B

2015-01-01

Thin films of titanium carbonitride (TiCN) were fabricated by DC magnetron sputtering on medical grade steel. The biocompatibility of the coating was further enhanced by growing hydroxyapatite crystals over the TiCN-coated substrates using biologically activated ammonia from synthetic urine. The coatings were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM)-energy dispersive spectroscopy, and Raman spectroscopy. The electrochemical behavior of the coatings was determined in simulated body fluid. In addition, hemocompatibility was assessed by monitoring the attachment of platelets on the coating using SEM. The wettability of the coatings was measured in order to correlate with biocompatibility results. Formation of a coating with granular morphology and the preferred orientation was confirmed by SEM and X-ray diffraction results. The hydroxyapatite coating led to a decrease in thrombogenicity, resulting in controlled blood clot formation, hence demonstrating the hemocompatibility of the coating.

[Experimental study on the retentive force of cobalt-chromium alloy, pure titanium and vitallium cast clasps in the simulated 3-year clinical use].

PubMed

Yan, Hai-xin; Zhao, Yan-bo; Qin, Li-mei; Zhu, Hai-ting; Wu, Lin

2015-12-01

To investigate the changes of retentive force of cobalt-chromium alloy, pure titanium and vitallium cast clasps in the simulated 3-year clinical use. Fifteen metal abutment crowns made of No.QT800-2 nodular cast iron were used in the test. Five clasps from each of the following alloys: cobalt-chromium alloy, pure titanium and vitallium were fabricated. The undercut depth was 0.25 mm. A masticatory simulator was used to cycle the clasp on and off the metal abutment crown 5000 times, simulating 3-year clinical use. Retentive force was measured 11 times during this process. SPSS13.0 software package was used to analyze the results. Casting defects were observed using X-ray non destructive testing (X-ray NDT) before cyclic test. Surface characteristics were qualitatively evaluated using scanning electron microscope (SEM) before and after cyclic test. The results indicated that there were significant differences (P=0.000) in the retentive force of the 3 groups before and after the cyclic test. The highest retentive force was recorded in the vitallium clasps, and the lowest retentive force was measured in the pure titanium clasps. The results of X-ray NDT depicted the typical casting defect seen at the end of the connector. SEM examination revealed that no evidence of pores and cracks in the inner surfaces of the 3 groups was found before cyclic test. Wear was evident in the inner surfaces of the 3 groups but none of the clasps exhibited any evidence of cracks after cyclic test through SEM examination. In this in vitro test, vitallium clasps show the best retentive force in the 3 groups before and after 5000 cycles at 0.25 mm undercut depth. Cobalt-chromium alloy and vitallium clasps can maintain ideal retentive force at 0.25mm undercut depth in the long-term use. Wear may be one of the reasons for the loss of retentive force of clasps in the cyclic test.

Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation

NASA Astrophysics Data System (ADS)

Surucu, Seda; Masur, Kai; Turkoglu Sasmazel, Hilal; Von Woedtke, Thomas; Weltmann, Klaus Dieter

2016-11-01

This paper reports Ar gas, Ar + O2, Ar + O2 + N2 gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O2 + N2 gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O2 + N2 gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9° ± 1.0 and 75.6° ± 0.1, respectively compared to the untreated samples (126.5°). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on/within scaffolds.

Investigation of physical and mechanical properties of (BaSnO3)x(Bi,Pb)-2223 composite

NASA Astrophysics Data System (ADS)

Habanjar, K.; Barakat, M. M. E.; Awad, R.

2017-07-01

The effect of BaSnO3 nanoparticles addition on the structural and mechanical properties of (Bi,Pb)-2223 superconducting phase by means of X-rays diffraction analysis (XRD), scanning electron microscope (SEM), electrical resistance and Vickers microhardness measurement was studied. BaSnO3 nanomaterial and (BaSnO3)x(Bi,Pb)-2223 superconducting samples were prepared using co-precipitation method and standard solid-state reaction techniques, respectively. From XRD data, the addition of BaSnO3 into (Bi,Pb)-2223 phase does not affect the tetragonal structure and the lattice parameters. SEM images indicate that the microstructure of (Bi,Pb)-2223 was enhanced by adding BaSnO3 nanoparticles by filling its pores and voids. The superconducting transition temperature Tc as well as the critical transport current density Jc, estimated from electrical resistivity measurements, are increased up to x = 0.5 wt%, then decreased with further increase in x. Vickers microhardness measurements Hv were carried out at room temperature as a function of applied. The experimental Hv results were analysed in view of Meyer’s law, Hays and Kendall (HK) approach, elastic/plastic deformation (EPD) and proportional specimen resistance (PSR). All samples exhibit normal indentation size effect (ISE), in addition to that, the analysis shows that the Hays and Kendall model is the most suitable one to describe the load independent microhardness for (BaSnO3)x(Bi,Pb)-2223 superconducting samples.

Laser-induced Multi-energy Processing in Diamond Growth

DTIC Science & Technology

2012-05-01

microscopy (SEM) and energy dispersive X - ray (EDX) measurements, Drs. Yi Liu and Shah Valloppilly from Nebraska Center for Materials and Nanoscience...NCMN) at UNL for help on X - Ray diffraction (XRD) measurements, and Professor Steve W. Martin and Dr. Young Sik Kim from the Department of Material...spectroscopy and X - ray diffraction ................... 62 4.4 Conclusions

The Effect of Buffer Types on the In0.82Ga0.18As Epitaxial Layer Grown on an InP (100) Substrate.

PubMed

Zhang, Min; Guo, Zuoxing; Zhao, Liang; Yang, Shen; Zhao, Lei

2018-06-08

In 0.82 Ga 0.18 As epitaxial layers were grown on InP (100) substrates at 530 °C by a low-pressure metalorganic chemical vapor deposition (LP-MOCVD) technique. The effects of different buffer structures, such as a single buffer layer, compositionally graded buffer layers, and superlattice buffer layers, on the crystalline quality and property were investigated. Double-crystal X-ray diffraction (DC-XRD) measurement, Raman scattering spectrum, and Hall measurements were used to evaluate the crystalline quality and electrical property. Scanning electron microscope (SEM), atomic force microscope (AFM), and transmission electron microscope (TEM) were used to characterize the surface morphology and microstructure, respectively. Compared with the In 0.82 Ga 0.18 As epitaxial layer directly grown on an InP substrate, the quality of the sample is not obviously improved by using a single In 0.82 Ga 0.18 As buffer layer. By introducing the graded In x Ga 1−x As buffer layers, it was found that the dislocation density in the epitaxial layer significantly decreased and the surface quality improved remarkably. In addition, the number of dislocations in the epitaxial layer greatly decreased under the combined action of multi-potential wells and potential barriers by the introduction of a In 0.82 Ga 0.18 As/In 0.82 Al 0.18 As superlattice buffer. However, the surface subsequently roughened, which may be explained by surface undulation.

Dynamic x-ray imaging of laser-driven nanoplasmas

NASA Astrophysics Data System (ADS)

Fennel, Thomas

2016-05-01

A major promise of current x-ray science at free electron lasers is the realization of unprecedented imaging capabilities for resolving the structure and ultrafast dynamics of matter with nanometer spatial and femtosecond temporal resolution or even below via single-shot x-ray diffraction. Laser-driven atomic clusters and nanoparticles provide an ideal platform for developing and demonstrating the required technology to extract the ultrafast transient spatiotemporal dynamics from the diffraction images. In this talk, the perspectives and challenges of dynamic x-ray imaging will be discussed using complete self-consistent microscopic electromagnetic simulations of IR pump x-ray probe imaging for the example of clusters. The results of the microscopic particle-in-cell simulations (MicPIC) enable the simulation-assisted reconstruction of corresponding experimental data. This capability is demonstrated by converting recently measured LCLS data into a ultrahigh resolution movie of laser-induced plasma expansion. Finally, routes towards reaching attosecond time resolution in the visualization of complex dynamical processes in matter by x-ray diffraction will be discussed.

Ultraviolet germicidal irradiation and its effects on elemental distributions in mouse embryonic fibroblast cells in x-ray fluorescence microanalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Qiaoling; Vogt, Stefan; Lai, Barry

Rapidly-frozen hydrated (cryopreserved) specimens combined with cryo-scanning x-ray fluorescence microscopy provide an ideal approach for investigating elemental distributions in biological cells and tissues. However, because cryopreservation does not deactivate potentially infectious agents associated with Risk Group 2 biological materials, one must be concerned with contamination of expensive and complicated cryogenic x-ray microscopes when working with such materials. We employed ultraviolet germicidal irradiation to decontaminate previously cryopreserved cells under liquid nitrogen, and then investigated its effects on elemental distributions under both frozen hydrated and freeze dried states with x-ray fluorescence microscopy. We show that the contents and distributions of most biologicallymore » important elements remain nearly unchanged when compared with non-ultraviolet-irradiated counterparts, even after multiple cycles of ultraviolet germicidal irradiation and cryogenic x-ray imaging. This provides a potential pathway for rendering Risk Group 2 biological materials safe for handling in multiuser cryogenic x-ray microscopes without affecting the fidelity of the results.« less

Ultraviolet germicidal irradiation and its effects on elemental distributions in mouse embryonic fibroblast cells in x-ray fluorescence microanalysis

DOE PAGES

Jin, Qiaoling; Vogt, Stefan; Lai, Barry; ...

2015-02-23

Rapidly-frozen hydrated (cryopreserved) specimens combined with cryo-scanning x-ray fluorescence microscopy provide an ideal approach for investigating elemental distributions in biological cells and tissues. However, because cryopreservation does not deactivate potentially infectious agents associated with Risk Group 2 biological materials, one must be concerned with contamination of expensive and complicated cryogenic x-ray microscopes when working with such materials. We employed ultraviolet germicidal irradiation to decontaminate previously cryopreserved cells under liquid nitrogen, and then investigated its effects on elemental distributions under both frozen hydrated and freeze dried states with x-ray fluorescence microscopy. We show that the contents and distributions of most biologicallymore » important elements remain nearly unchanged when compared with non-ultraviolet-irradiated counterparts, even after multiple cycles of ultraviolet germicidal irradiation and cryogenic x-ray imaging. This provides a potential pathway for rendering Risk Group 2 biological materials safe for handling in multiuser cryogenic x-ray microscopes without affecting the fidelity of the results.« less

Synthesis of magnetic biocomposite for efficient adsorption of azo dye from aqueous solution.

PubMed

Sivashankar, R; Sathya, A B; Krishnakumar, Uma; Sivasubramanian, V

2015-11-01

A novel magnetic biocomposite was synthesized using metal chlorides and aquatic macrophytes by co-precipitation method. The resulting product, magnetic biocomposite was characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). The adsorption performance of the magnetic biocomposite was tested with removal of Metanil Yellow dye from aqueous solution. The effect of influencing parameters such as initial dye concentration, solution pH and agitation were investigated. The equilibrium isotherm was well described by the Langmuir model with the with maximum adsorption capacity of 90.91mg/g. Adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the magnetic biocomposite could efficiently adsorb the azo dyes from aqueous solution, and the spent adsorbents could be recovered completely by magnetic separation process. Therefore, the prepared magnetic biocomposite could thus be used as promising adsorbent for the removal of azo dyes from polluted water. Copyright © 2015 Elsevier Inc. All rights reserved.

Bioresponsive Materials for Drug Delivery Based on Carboxymethyl Chitosan/Poly(γ-Glutamic Acid) Composite Microparticles

PubMed Central

Yan, Xiaoting; Tong, Zongrui; Chen, Yu; Mo, Yanghe; Feng, Huaiyu; Li, Peng; Qu, Xiaosai; Jin, Shaohua

2017-01-01

Carboxymethyl chitosan (CMCS) microparticles are a potential candidate for hemostatic wound dressing. However, its low swelling property limits its hemostatic performance. Poly(γ-glutamic acid) (PGA) is a natural polymer with excellent hydrophilicity. In the current study, a novel CMCS/PGA composite microparticles with a dual-network structure was prepared by the emulsification/internal gelation method. The structure and thermal stability of the composite were determined by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The effects of preparation conditions on the swelling behavior of the composite were investigated. The results indicate that the swelling property of CMCS/PGA composite microparticles is pH sensitive. Levofloxacin (LFX) was immobilized in the composite microparticles as a model drug to evaluate the drug delivery performance of the composite. The release kinetics of LFX from the composite microparticles with different structures was determined. The results suggest that the CMCS/PGA composite microparticles are an excellent candidate carrier for drug delivery. PMID:28452963

Extreme Pressure Synergistic Mechanism of Bismuth Naphthenate and Sulfurized Isobutene Additives

NASA Astrophysics Data System (ADS)

Xu, Xin; Hu, Jianqiang; Yang, Shizhao; Xie, Feng; Guo, Li

A four-ball tester was used to evaluate the tribological performances of bismuth naphthenate (BiNap), sulfurized isobutene (VSB), and their combinations. The results show that the antiwear properties of BiNap and VSB are not very visible, but they possess good extreme pressure (EP) properties, particularly sulfur containing bismuth additives. Synergistic EP properties of BiNap with various sulfur-containing additives were investigated. The results indicate that BiNap exhibits good EP synergism with sulfur-containing additives. The surface analytical tools, such as X-ray photoelectron spectrometer (XPS) scanning electron microscope (SEM) and energy dispersive X-ray (EDX), were used to investigate the topography, composition contents, and depth profile of some typical elements on the rubbing surface. Smooth topography of wear scar further confirms that the additive showed good EP capacities, and XPS and EDX analyzes indicate that tribochemical mixed protective films composed of bismuth, bismuth oxides, sulfides, and sulfates are formed on the rubbing surface, which improves the tribological properties of lubricants. In particular, a large number of bismuth atoms and bismuth sulfides play an important role in improving the EP properties of oils.

The Effect of the Acetone Extract of Arctotis arctotoides (Asteraceae) on the Growth and Ultrastructure of Some Opportunistic Fungi Associated with HIV/AIDS

PubMed Central

Otang, Wilfred M.; Grierson, Donald S.; Ndip, Roland N.

2011-01-01

In this study, the effect of the acetone extract of Arctotis arctotoides (L.f.) O. Hoffm. (Asteraceae) on the growth and ultrastructure of some opportunistic fungi associated with HIV/AIDS was analyzed by means of scanning electron microscope (SEM). Remarkable morphological alterations in the fungal mycelia which were attributed to the loss of cell wall strength ranged from loss of turgidity and uniformity, collapse of entire hyphae to evident destruction of the hyphae. The elements responsible for giving the fungi their characteristic virulence were detected and quantified by energy dispersive X-ray microanalysis techniques. X-ray microanalysis showed the specific spectra of sodium, potassium and sulfur as the principal intersection of the four pathogenic fungi studied. Since these ions have the potential of fostering fungal invasion by altering the permeability of hosts’ membranes, their presence was considered inherent to the pathogenicity of the opportunistic fungi. Hence, these findings indicate the potential of the crude extract of A. arctotoides in preventing fungal invasion and subsequent infection of host’s membranes. PMID:22272130

Macrosegregation of GeSi Alloys Grown in a Static Magnetic Field

NASA Technical Reports Server (NTRS)

Ritter, T. M.; Volz, M. P.; Cobb, S. D.; Szofran, F. R.

1999-01-01

Axial and radial macrosegregation profiles have been determined for GeSi alloy crystals grown by the vertical Bridgman technique. An axial 5 Tesla magnetic field was applied to several samples during growth to decrease the melt velocities by means of the Lorentz force. Compositions were measured with either energy dispersive X-ray spectroscopy (EDS) on a scanning electron microscope (SEM) or by wavelength dispersive X-ray spectroscopy (WDS) on a microprobe. The crystals were processed in graphite, hot-pressed boron nitride (BN), and pyrolytic boron nitride (PBN) ampoules, which produced various solid-liquid interface shapes during solidification. Those samples grown in a graphite ampoule exhibited radial profiles consistent with a highly concave interface and axial profiles indicative of complete mixing in the melt. The samples grown in BN and PBN ampoules had less radial variation. Axial macrosegregation profiles of these samples fell between the predictions for a completely mixed melt and one where solute transport is dominated by diffusion. Possible explanations for the apparent insufficiency of the magnetic field to achieve diffusion controlled growth conditions are discussed.

Synthesis and characterization of mangan oxide coated sand from Capkala kaolin

NASA Astrophysics Data System (ADS)

Destiarti, Lia; Wahyuni, Nelly; Prawatya, Yopa Eka; Sasri, Risya

2017-03-01

Synthesis and characterization of mangan oxide coated sand from quartz sand fraction of Capkala kaolin has been conducted. There were two methods on synthesis of Mangan Oxide Coated Sand (MOCS) from Capkala Kaolin compared in this research. Characterization of MOCS was done by using Scanning Electron Microscope/Energy Dispersive X-Ray Spectrometer (SEM/EDX) and X-Ray Diffraction (XRD). The MOCS was tested to reduce phosphate in laundry waste. The result showed that the natural sand had bigger agregates and a relatively uniform structural orientation while both MOCS had heterogen structural orientation and manganese oxide formed in cluster. Manganese in first and second methods were 1,93% and 2,63%, respectively. The XRD spectrum showed clear reflections at 22,80°, 36,04°, 37,60° and a broad band at 26,62° (SiO2). Based on XRD spectrum, it can be concluded that mineral constituents of MOCS was verified corresponding to pyrolusite (MnO2). The former MOCS could reduce almost 60% while the later could reduce 70% phosphate in laundry waste.

Reutilization of the expired tetracycline for lithium ion battery anode.

PubMed

Hou, Hongying; Dai, Zhipeng; Liu, Xianxi; Yao, Yuan; Liao, Qishu; Yu, Chengyi; Li, Dongdong

2018-07-15

Waste antibiotics into the natural environment are the large challenges to the environmental protection and the human health, and the unreasonable disposal of the expired antibiotics is a major pollution source. Herein, to achieve the innocent treatment and the resource recovery, the expired tetracycline was tried to be reutilized as the electrode active material in lithium ion battery (LIB) for the first time. The micro-structure and element component of the expired tetracycline were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Furthermore, the corresponding electrochemical performances were also investigated by galvanostatic charge/discharge and cyclic voltammetry (CV). To be satisfactory, the expired-tetracycline-based electrode delivered the initial specific discharge capacity of 371.6mAh/g and the reversible specific capacity of 304.1mAh/g after 200cycles. The decent results will not only offer an effective strategy to recycle the expired tetracycline, but also shed a new light on the cyclic economy and the sustainable development. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of micro-oxidation on joints of C/C composites and GH3044 for large-size aerospace parts

NASA Astrophysics Data System (ADS)

Shi, Xiaohong; Jin, Xiuxiu; Yan, Ningning; Yang, Li

2017-11-01

To improve the bonding strength of carbon/carbon (C/C) composites and GH3044 nickel-based superalloy, the bonding interlayer with Ti/Ni/Cu/Ni multiple foils were prepared by a two-step technique involving micro-oxidation and partial transient liquid phase (PTLP) process. Interface characteristics and mechanical behavior of joints were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser scanning confocal microscope (LSCM) and energy X-ray dispersive spectrometer (EDS). Results show that a porous layer on C/C composites is formed by micro-oxidation for more than 2 min at 1073 K in air, which provides a diffusion path for liquid phase to infiltrate into C/C substrate and generate a wedge interlocking interface. After micro-oxidation for 4 min, the shear strength of joints reaches 32.09 ± 1.98 MPa what is 36.73% higher than that of joints without micro-oxidation (23.47 ± 1.15 MPa). The increase of shear strength remarkably depends on physical interlocking and chemical bonding at porous interface.

Assessment of the Effects Exerted by Acid and Alkaline Solutions on Bone: Is Chemistry the Answer?

PubMed

Amadasi, Alberto; Camici, Arianna; Porta, Davide; Cucca, Lucia; Merli, Daniele; Milanese, Chiara; Profumo, Antonella; Rassifi, Nabila; Cattaneo, Cristina

2017-09-01

The treatment of corpses with extremely acid or basic liquids is sometimes performed in criminal contexts. A thorough characterization by chemical analysis may provide further help to macroscopic and microscopic analysis; 63 porcine bone samples were treated with solutions at different pH (1-14) for immersion periods up to 70 days, as well as in extremely acidic sulfuric acid solutions (9 M/18 M) and extremely basic sodium hydroxide. Inductively coupled optical emission spectrometry (ICP-OES)/plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) showed that only the sulfuric acid solution 18 M was able to completely dissolve the sample. In addition, chemical analysis allowed to recognize the contact between bone and substances. Hydrated calcium sulfate arose from extreme pH. The possibility of detecting the presence of human material within the residual solution was demonstrated, especially with FT-IR, ICP-OES, and EDX. © 2017 American Academy of Forensic Sciences.

Structural and magnetic properties of Ni0.8M0.2Fe2O4 (M = Cu, Co) nano-crystalline ferrites

NASA Astrophysics Data System (ADS)

Vijaya Babu, K.; Satyanarayana, G.; Sailaja, B.; Santosh Kumar, G. V.; Jalaiah, K.; Ravi, M.

2018-06-01

Nano-crystalline nickel ferrites are interesting materials due to their large physical and magnetic properties. In the present work, two kinds of spinel ferrites Ni0.8M0.2Fe2O4 (M = Cu, Co) are synthesized by using sol-gel auto-combustion method and the results are compared with NiFe2O4. The structural properties of synthesized ferrites are determined by using X-ray powder diffraction; scanning electron microscope and Fourier transform infrared spectroscopy. The cation distribution obtained from X-ray diffraction show that cobalt/copper occupies only tetrahedral site in spinel lattice. The lattice constant increases with the substitution of cobalt/copper. The structural parameters like bond lengths, tetrahedral and octahedral edges have been varied with the substitution. The microstructural study is carried out by using SEM technique and the average grain size is increased with nickel ferrite. The initial permeability (μi) is improving with the substitution. The observed g-value from ESR is approximately equal to standard value.

Enhancement of antioxidant and antibacterial properties for tannin acid/chitosan/tripolyphosphate nanoparticles filled electrospinning films: Surface modification of sliver nanoparticles.

PubMed

Zhan, Fuchao; Sheng, Feng; Yan, Xiangxing; Zhu, Yingrui; Jin, Weiping; Li, Jing; Li, Bin

2017-11-01

The tannin acid/chitosan/tripolyphosphate nanoparticles were encapsulated in polyvinyl alcohol (PVA)/poly-acrylic acid (PAA) electrospinning films by electrostatic spinning technology. To optimize the prepared condition, properties and morphology of nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscope (TEM). The optimized initial concentration of tannin, chitosan and tripolyphosphate solutions were 1, 1, 0.5mg/ml, respectively, with adding proportion for 5:5:1. The average diameter of tannin acid/chitosan/tripolyphosphate nanoparticles was ∼80nm. The electrospinning films showed an excellent water-resistant property with 0.5wt%N,N'-Methylenebisacrylamide (MBA). Due to the antioxidant and antibacterial of tannic acid, the films possessed these properties. The antioxidant and antibacterial of these fibers significantly improved after in situ formation of silver nanoparticles (AgNPs). Electrospun films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrothermal synthesis and characterization of hydroxyapatite and fluorhydroxyapatite nano-size powders.

PubMed

Montazeri, Leila; Javadpour, Jafar; Shokrgozar, Mohammad Ali; Bonakdar, Shahin; Javadian, Sayfoddin

2010-08-01

Pure hydroxyapatite (HAp) and fluoride-containing apatite powders (FHAp) were synthesized using a hydrothermal method. The powders were assessed by x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and F-selective electrode. X-ray diffraction results revealed the formation of single phase apatite structure for all the compositions synthesized in this work. However, the addition of a fluoride ion led to a systematic shift in the (3 0 0) peak of the XRD pattern as well as modifications in the FTIR spectra. It was found that the efficiency of fluoride ion incorporation decreased with the increase in the fluoride ion content. Fluorine incorporation efficiency was around 60% for most of the FHAp samples prepared in the current study. Smaller and less agglomerated particles were obtained by fluorine substitution. The bioactivity of the powder samples with different fluoride contents was compared by performing cell proliferation, alkaline phosphatase (ALP) and Alizarin red staining assays. Human osteoblast cells were used to assess the cellular responses to the powder samples in this study. Results demonstrated a strong dependence of different cell activities on the level of fluoridation.

Microstructures and Properties of Laser Cladding Al-TiC-CeO2 Composite Coatings

PubMed Central

Kong, Dejun; Song, Renguo

2018-01-01

Al-TiC-CeO2 composite coatings have been prepared by using a laser cladding technique, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), a 3D microscope system, X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that an Al-Fe phase appears in the coatings under different applied laser powers and shows good metallurgical bonding with the matrix. The dilution rate of the coating first decreases and then increases with increasing laser power. The coating was transformed from massive and short rod-like structures into a fine granular structure, and the effect of fine grain strengthening is significant. The microhardness of the coatings first decreases and then increases with increasing laser power, and the maximum microhardness can reach 964.3 HV0.2. In addition, the residual stress of the coating surface was tensile stress, and crack size increases with increasing stress. When the laser power was 1.6 kW, the coating showed high corrosion resistance. PMID:29373555

Microstructures and Properties of Laser Cladding Al-TiC-CeO₂ Composite Coatings.

PubMed

He, Xing; Kong, Dejun; Song, Renguo

2018-01-26

Al-TiC-CeO₂ composite coatings have been prepared by using a laser cladding technique, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), a 3D microscope system, X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that an Al-Fe phase appears in the coatings under different applied laser powers and shows good metallurgical bonding with the matrix. The dilution rate of the coating first decreases and then increases with increasing laser power. The coating was transformed from massive and short rod-like structures into a fine granular structure, and the effect of fine grain strengthening is significant. The microhardness of the coatings first decreases and then increases with increasing laser power, and the maximum microhardness can reach 964.3 HV 0.2 . In addition, the residual stress of the coating surface was tensile stress, and crack size increases with increasing stress. When the laser power was 1.6 kW, the coating showed high corrosion resistance.

Bacteria-assisted preparation of nano α-Fe2O3 red pigment powders from waste ferrous sulfate.

PubMed

Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui

2016-11-05

Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe2O3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe2O3 red pigment powders contained 98.24wt.% of Fe2O3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22nm to 86nm and averaged at 45nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments. Copyright © 2016 Elsevier B.V. All rights reserved.

Design and fabrication of x-ray Kirkpatrick-Baez microscope for ICF

NASA Astrophysics Data System (ADS)

Mu, Baozhong; Wang, Zhanshan; Huang, Shengling; Yi, Shengzhen; Shen, Zhengxiang

2007-12-01

A hard x-ray (8 keV, Kα line of Cu) Kirkpatrick-Baez (KB) microscope was designed for the diagnostics of inertial confinement fusion (ICF). Three main parts including optical design, fabrication of multilayers, and alignment method were discussed in this paper. According to the deduced equation of aberration in whole field, an optical system was designed, which gives attention to not only spatial resolution but also the collection efficiency. Tungsten (W) and boron carbide (B4C) were chosen as multilayer materials and the non-periodic multilayer with 40 layers was deposited. The measured reflectivity by XRD is better than 18% in the bandwidth range of about 0.3%. Super accurately alignment is another difficulty in the application of KB microscope. To meet the requirements of pointing and co-focusing, a binocular laser pointer which is flexible enough was designed. Finally, an 8keV x-ray tube was used as source in x-ray imaging experiment and images with magnification of 2× were obtained.

Fabrication and Characterization of Dense Zirconia and Zirconia-Silica Ceramic Nanofibers

PubMed Central

Guo, Guangqing; Fan, Yuwei

2011-01-01

The objective of this study was to prepare dense zirconia-yttria (ZY), zirconia-silica (ZS) and zirconia-yttria-silica (ZYS) nanofibers as reinforcing elements for dental composites. Zirconium (IV) propoxide, yttrium nitrate hexahydrate, and tetraethyl orthosilicate (TEOS) were used as precursors for the preparation of zirconia, yttria, and silica sols. A small amount (1–1.5 wt%) of polyethylene oxide (PEO) was used as a carry polymer. The sols were preheated at 70 °C before electrospinning and their viscosity was measured with a viscometer at different heating time. The gel point was determined by viscosity–time (η–t) curve. The ZY, ZS and ZYS gel nanofibers were prepared using a special reactive electrospinning device under the conditions near the gel point. The as-prepared gel nanofibers had diameters between 200 and 400 nm. Dense (nonporous) ceramic nanofibers of zirconia-yttria (96/4), zirconia-silica (80/20) and zirconia-yttria-silica (76.8/3.2/20) with diameter of 100–300 nm were obtained by subsequent calcinations at different temperatures. The gel and ceramic nanofibers obtained were characterized by scanning electron microscope (SEM), high-resolution field-emission scanning electron microscope (FE-SEM), thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC), Fourier transform infrared spectrometer (FT-IR), and X-ray diffraction (XRD). SEM micrograph revealed that ceramic ZY nanofibers had grained structure, while ceramic ZS and ZYS nanofibers had smooth surfaces, both showing no visible porosity under FE-SEM. Complete removal of the polymer PEO was confirmed by TGA/DSC and FT-IR. The formation of tetragonal phase of zirconia and amorphous silica was proved by XRD. In conclusion, dense zirconia-based ceramic nanofibers can be fabricated using the new reactive sol–gel electrospinning technology with minimum organic polymer additives. PMID:21133090

X-Ray Optics at NASA Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

O'Dell, Stephen L.; Atkins, Carolyn; Broadway, David M.; Elsner, Ronald F.; Gaskin, Jessica A.; Gubarev, Mikhail V.; Kilaru, Kiranmayee; Kolodziejczak, Jeffery J.; Ramsey, Brian D.; Roche, Jacqueline M.;

Effect of annealing temperature and copper mole ratio on the morphology, structure and magnetic properties of Mg0.5-xCuxZn0.5Fe2O4 nanoparticles prepared by the modified Pechini method

NASA Astrophysics Data System (ADS)

Loghman-Estarki, M. R.; Torkian, S.; Rastabi, R. Amini; Ghasemi, A.

2017-11-01

In this study, magnesium copper zinc ferrite (MCZ) nanoparticles were synthesized by the modified Pechini method. In this approach, the magnesium nitrate, copper nitrate, zinc nitrate, iron nitrate, citric acid and diethylene glycol (instead of ethylene glycol in conventional Pechini method) were used as a source of Mg2+, Cu2+, Zn2+, complex and stabilizer and solvent agent, respectively. The effect of annealing temperature and copper mole ratio on the morphology, structural and magnetic properties of Mg0.5xCuxZn0.5Fe2O4 (x = 0-0.5) nanoparticles were investigated. Various characterization methods, including X-ray diffraction (XRD), field emission scanning electron microscope (FeSEM), energy-dispersive spectroscopy (EDS), X-ray mapping, Fourier transforms infrared spectroscopy (FTIR), adsorption-desorption isotherm and vibrating sample magnetometer (VSM) were used to study the phase, microstructure, particle size, elemental distribution, functional group determination, porosity and magnetic properties of nanoparticles, respectively. The results showed that cubic spinel phase with various morphologies such as semi-spherical, sheet-like shapes was obtained by the modified Pechini method. Furthermore, the nanoparticles with the x value of 0.2, annealed at 700 °C have the highest saturation magnetization (Ms = 56.5 emu/g) among the other synthesized MCZ ferrite nanoparticles.

Structural and spectral properties of undoped and tungsten doped Zn3(PO4)2ZnO nanopowders

NASA Astrophysics Data System (ADS)

Satyavathi, K.; Subba Rao, M.; Nagabhaskararao, Y.; Cole, Sandhya

2018-01-01

Pure and tungsten doped Zn3(PO4)2ZnO nanopowders (NPs) are prepared using sol-gel method. It has the longest track record of used in dentistry. It is used for cementation of inlays, crowns and orthodontic appliances. The systematic investigations like X-ray Diffraction (XRD), Scanning electron microscope (SEM) with energy dispersive X-ray (EDX) spectroscope, Transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy, Optical absorption, Photoluminescence (PL) and Electron Paramagnetic Resonance (EPR) spectroscopic techniques are carried out for the prepared NPs. XRD pattern reveals that the prepared samples are in crystalline nature in which Zn3(PO4)2 corresponding to monoclinic phase and ZnO corresponding to hexagonal wurtzite phase, the average crystallite size of prepared nanopowders is in the range of 20-30 nm. The lattice strain, lattice cell parameters, unit cell volume and dislocation density of the prepared NPs are also calculated. The morphology of the prepared NPs is analyzed with SEM and TEM images. The distribution of Zn, P, O and W species in the prepared samples are identified by the chemical composition mapping through EDX. IR spectra of prepared samples exhibit the characteristic sharp absorption band peaks. The sharp absorption bands observed in the region 1200-900 cm-1 are due to complex stretching of characteristic PO43- groups. The absorption spectra exhibit a broad band around 696 nm is recognized due to 2B2g → 2B1g (dxy → dx2- y2) transition of tungsten ions. The PL spectra exhibit four emission peaks in the visible region indicating the quantum-confinement-induced photoluminescence. The CIE chromaticity diagram suggests that the prepared NPs have good color purity. The EPR spectra indicate that the W5+ ions occupy octahedral site symmetry in the host lattice.

[Based on Curing Age of Calcined Coal Gangue Fine Aggregate Mortar of X-Ray Diffraction and Scanning Electron Microscopy Analysis].

PubMed

Dong, Zuo-chao; Xia, Jun-wu; Duan, Xiao-mu; Cao, Ji-chang

2016-03-01

By using X-ray diffraction (XRD) and environmental scanning electron microscope (SEM) analysis method, we stud- ied the activity of coal gangue fine aggregate under different calcination temperature. In view of the activity of the highest-700 degrees C high temperature calcined coal gangue fine aggregate mortar of hydration products, microstructure and strength were discussed in this paper, and the change laws of mortar strength with curing age (3, 7, 14, 28, 60 and 90 d) growth were analyzed. Test results showed that coal gangue fine aggregate with the increase of calcination temperature, the active gradually increases. When the calcination temperature reaches 700 degrees C, the activity of coal gangue fine aggregate is the highest. When calcining temperature continues to rise, activity falls. After 700 degrees C high temperature calcined coal gangue fine aggregate has obvious ash activity, the active components of SiO2 and Al2 O3 can be with cement hydration products in a certain degree of secondary hydration reaction. Through on the top of the activity of different curing age 700 degrees C high temperature calcined coal gangue fine aggregate mortar, XRD and SEM analysis showed that with the increase of curing age, secondary hydration reaction will be more fully, and the amount of hydration products also gradually increases. Compared with the early ages of the cement mortar, the products are more stable hydration products filling in mortar microscopic pore, which can further improve the microstructure of mortar, strengthen the interface performance of the mortar. The mortar internal structure is more uniform, calcined coal gangue fine aggregate and cement mortar are more of a strong continuous whole, which increase the later strength of hardened cement mortar, 700 degrees C high temperature calcined coal gangue fine aggregate pozzolanic effect is obvious.

Scanning transmission x-ray microscope for materials science spectromicroscopy at the ALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warwick, T.; Seal, S.; Shin, H.

1997-04-01

The brightness of the Advanced Light Source will be exploited by several new instruments for materials science spectromicroscopy over the next year or so. The first of these to become operational is a scanning transmission x-ray microscope with which near edge x-ray absorption spectra (NEXAFS) can be measured on spatial features of sub-micron size. Here the authors describe the instrument as it is presently implemented, its capabilities, some studies made to date and the developments to come. The Scanning Transmission X-ray Microscope makes use of a zone plate lens to produce a small x-ray spot with which to perform absorptionmore » spectroscopy through thin samples. The x-ray beam from ALS undulator beamline 7.0 emerges into the microscope vessel through a silicon nitride vacuum window 160nm thick and 300{mu}m square. The vessel is filled with helium at atmospheric pressure. The zone plate lens is illuminated 1mm downstream from the vacuum window and forms an image in first order of a pinhole which is 3m upstream in the beamline. An order sorting aperture passes the first order converging light and blocks the unfocused zero order. The sample is at the focus a few mm downstream of the zone plate and mounted from a scanning piezo stage which rasters in x and y so that an image is formed, pixel by pixel, by an intensity detector behind the sample. Absorption spectra are measured point-by-point as the photon energy is scanned by rotating the diffraction grating in the monochromator and changing the undulator gap.« less

1998 Technology Showcase. JOAP International Condition Monitoring Conference.

DTIC Science & Technology

1998-04-01

Systems using Automated SEM/ EDX and New Diagnostic Routines 276 N. W Farrant & T. Luckhurst ADVANCED DIAGNOSTIC SYSTEMS Model-Based Diagnostics of Gas...Microscopy with Energy Dispersive X-Ray (SEM/ EDX ) micro analysis packages and Energy Dispersive X-Ray Fluorescence (EDXRF) analytical equipment. Therqfore...wear particles separated by ferrogram method. a- I WEAR PARTICLE A SLAS 97 (HOME PAGE) Fig I Home Page NONFE;RROUS MATERIAL A wW~ a48 -1, rV fr , ý b

Driving the photoluminescent and structural properties of X2-Y2SiO5 by varying the dopant Dy3+ concentration towards cool WLED applications

NASA Astrophysics Data System (ADS)

Ramakrishna, G.; Nagabhushana, H.; Hareesh, K.; Sunitha, D. V.

2017-07-01

Dy3+ doped Y2SiO5 nanophosphors were synthesized by solution combustion technique using Calotropis gigantean milk latex and NaCl as fuel and flux respectively. Powder X-ray diffraction (PXRD) confirmed the formation of monoclinic X2-phase Y2SiO5 belonging to the phase group C2/c. Fourier transform infrared spectroscopy (FTIR) shows characteristic metal-oxygen (Y-O) vibration band at 721 cm-1. Transmission electron microscopic (TEM) and Scanning electron microscopic (SEM) morphological feature exhibits non-uniform almost spherical shaped nanosized particles. The photoluminescence (PL) emission peaks, recorded at 388 nm, showed radiative emissions at 483, 575 and 636 nm respectively. Judd-Ofelt (JO) analysis was carried out to estimate the radiative (AR) properties, radiative life time (τR), branching ratio (βR) and stimulated emission crossection (σλp). The CIE and CCT was estimated using McCamy empirical formula. In the beginning, the CIE co-ordinate values were lying in the light blue region. However, with increase in Dy3+ concentration the values shifted towards white region. CCT value was found to be ∼6984 K. Therefore, Y2SiO5:Dy3+ (9 mol%) can be used for cool day light and WLED applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aoki, Sadao; Namikawa, Tadahiro; Hoshino, Masato

A Zernike-type phase contrast hard X-ray microscope was constructed at the Photon Factory BL3C2 (KEK). A white beam from a bending magnet was monochromatized by a silicon double crystal monochromator. Monochromatic parallel X-ray beam illuminated a sample, and transmitted and diffracted X-ray beams were imaged by a Fresnel zone plate (FZP) which had the outer zone width of 100 nm. A phase plate made of a thin aluminum foil with a pinhole was set at the back focal plane of the FZP. The phase plate modulated the diffraction beam from the FZP, whereas a direct beam passed through the pinhole.more » The resolution of the microscope was measured by observing a tantalum test pattern at an X-ray energy of 9 keV. A 100nm line-and-space pattern could be resolved. X-ray montage pictures of growing eggs of artemia (plankton) were obtained.« less

FIB-SEM cathodoluminescence tomography: practical and theoretical considerations.

PubMed

De Winter, D A M; Lebbink, M N; Wiggers De Vries, D F; Post, J A; Drury, M R

2011-09-01

Focused ion beam-scanning electron microscope (FIB-SEM) tomography is a powerful application in obtaining three-dimensional (3D) information. The FIB creates a cross section and subsequently removes thin slices. The SEM takes images using secondary or backscattered electrons, or maps every slice using X-rays and/or electron backscatter diffraction patterns. The objective of this study is to assess the possibilities of combining FIB-SEM tomography with cathodoluminescence (CL) imaging. The intensity of CL emission is related to variations in defect or impurity concentrations. A potential problem with FIB-SEM CL tomography is that ion milling may change the defect state of the material and the CL emission. In addition the conventional tilted sample geometry used in FIB-SEM tomography is not compatible with conventional CL detectors. Here we examine the influence of the FIB on CL emission in natural diamond and the feasibility of FIB-SEM CL tomography. A systematic investigation establishes that the ion beam influences CL emission of diamond, with a dependency on both the ion beam and electron beam acceleration voltage. CL emission in natural diamond is enhanced particularly at low ion beam and electron beam voltages. This enhancement of the CL emission can be partly explained by an increase in surface defects induced by ion milling. CL emission enhancement could be used to improve the CL image quality. To conduct FIB-SEM CL tomography, a recently developed novel specimen geometry is adopted to enable sequential ion milling and CL imaging on an untilted sample. We show that CL imaging can be manually combined with FIB-SEM tomography with a modified protocol for 3D microstructure reconstruction. In principle, automated FIB-SEM CL tomography should be feasible, provided that dedicated CL detectors are developed that allow subsequent milling and CL imaging without manual intervention, as the current CL detector needs to be manually retracted before a slice can be milled. Due to the required high electron beam acceleration voltage for CL emission, the resolution for FIB-SEM CL tomography is currently limited to several hundreds of nm in XY and up to 650 nm in Z for diamonds. Opaque materials are likely to have an improved Z resolution, as CL emission generated deeper in the material is not able to escape from it. © 2011 The Authors Journal of Microscopy © 2011 Royal Microscopical Society.

Effect of nano BiPb-2212 phase addition on BiPb-2223 phase properties

NASA Astrophysics Data System (ADS)

Mohammed, N. H.; Abou-Aly, A. I.; Barakat, M. Me.; Hassan, M. S.

2018-06-01

BiPb-2212 phase in nanoscale was added to BiPb-2223 phase with a general stoichiometry of (Bi1.7Pb0.4Sr2.1Ca1.1Cu2.1O8+δ)x/Bi1.8Pb0.4Sr2.0Ca2.0Cu3.2O10+δ, 0.0 ≤ x  ≤ 2.5 wt.%. All samples were prepared by the standard solid-state reaction method. The prepared nano BiPb-2212 phase was characterized by X-ray powder diffraction (XRD) and transmission electron microscope (TEM). The prepared samples were characterized by XRD and the scanning electron microscope (SEM). XRD analysis indicated that the sample with x = 1.5 wt.% has the highest relative volume fraction for BiPb-2223 phase. Samples were examined by electrical resistivity and I-V measurements. There is no significant change in the superconducting transition temperature Tc for all samples. The highest critical current density Jc was recorded for the sample with x = 1.5 wt.%. The normalized excess conductivity (Δσ/σroom) was calculated according to Aslamazov-Larkin (AL) model. Four different fluctuating regions were recorded as the temperature decreased. The coherence length along the c-axis at 0 K ξc(0), interlayer coupling strength s, Fermi velocity vF of the carriers and Fermi energy EF were calculated for both samples with x = 0.0 wt.% and 1.5 wt.%.

Facile synthesis of one dimensional ZnO nanostructures for DSSC applications

NASA Astrophysics Data System (ADS)

Marimuthu, T.; Anandhan, N.

2016-05-01

Development of zinc oxide (ZnO) nanostructure based third generation dye sensitized solar cell is interesting compared to conventional silicon solar cells. ZnO nanostructured thin films were electrochemically deposited onto fluorine doped tin oxide (FTO) glass substrate. The effect of ethylene-diamine-tetra-acetic acid (EDTA) on structural, morphological and optical properties is investigated using X-ray diffraction (XRD) meter, field emission scanning electron microscope (FE-SEM) and micro Raman spectroscopy. XRD patterns reveal that the prepared nanostructures are hexagonal wutrzite structures with (101) plane orientation, the nanostructure prepared using EDTA exhibits better crystallinity. FE-SEM images illustrate that the morphological changes are observed from nanorod structure to cauliflower like structure as EDTA is added. Micro Raman spectra predict that cauliflower like structure possesses a higher crystalline nature with less atomic defects compared to nanorod structures. Dye sensitized solar cell (DSSC) is constructed for the optimized cauliflower structure, and open circuit voltage, short circuit density, fill factor and efficiency are estimated from the J-V curve.

Plasma-induced polymerization for enhancing paper hydrophobicity.

PubMed

Song, Zhaoping; Tang, Jiebin; Li, Junrong; Xiao, Huining

2013-01-30

Hydrophobic modification of cellulose fibers was conducted via plasma-induced polymerization in an attempt to graft the hydrophobic polymer chains on paper surface, this increasing the hydrophobicity of paper. Two hydrophobic monomers, butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA), were grafted on cellulose fibers, induced by atmospheric cold plasma. Various influencing factors associated with the plasma-induced grafting were investigated. Contact-angle measurement, Fourier Transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to ascertain the occurrence of the grafting and characterized the changes of the cellulose fiber after modification. The results showed that the hydrophobicity of the modified paper sheet was improved significantly after the plasma-induced grafting. The water contact angle on the paper surface reached up to 130°. The morphological differences between modified and unmodified samples were also revealed by SEM observation. The resulting paper is promising as a green-based packaging material. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fungi and bacteria involved in desert varnish formation

NASA Technical Reports Server (NTRS)

Taylor-George, S.; Palmer, F.; Staley, J. T.; Curtiss, B.; Adams, J. B.; Borns, D. J.

1983-01-01

Desert varnish is a coating of ferromanganese oxides and clays that develops on rock surfaces in arid to semi-arid regions. Active respiration but not photosynthesis was detected on varnished rock surfaces from the Sonoran Desert. Light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations, and cultivation experiments indicate that both fungi, primarily dematiaceous hyphomycetes, and bacteria are found on and within desert varnish coatings from the arid regions studied. Some fungi grow as microcolonial fungi (MCF) on rocks, and microscopic observations suggest MCF become incorporated in the varnish coating. SEM-EDAX (energy dispersive X-ray systems) analyses indicate the MCF contain 3 of the characteristic elements of varnish: iron, aluminum, and silicon. In some locations, MCF are also enriched in manganese relative to the rock substratum. Furthermore, some of the dematiaceous hyphomycetes that have been cultivated are able to oxidize manganese under laboratory conditions. It is possible that manganese-oxidizing bacteria, which are found in varnish, also play an important role in varnish formation.

Templated synthesis of nanoporous titania/nanocarbon composites

NASA Astrophysics Data System (ADS)

Mistry, Jayur

Hexagonally patterned (honeycomb structured) nano-porous titania finds distinct applications in the field of material science, electronics, and catalysis. The preparation of titania/nanocarbon composites was carried out using titanium iso-propoxide precursor and a viscous surfactant templated system arranged into nanoscopic channels of water and iso-octane. Nanocarbon was introduced into the titania pores, as it was dispersed into the water (used to increase the W0), while making templets. Prepared titania/nanocarbon composites were analyzed under scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) after a specific heat treatment. SEM and TEM allows us to see the morphology of the hexagonally patterned templates and XRD shows the change in the crystallinity of the titania after the heat treatment. Further tests are run with the Solartron™ CellTest potentiostat syste, which, allows us to study the electrical properties of the nanocomposites. The composites synthesized have wide applications in number of fields, including energy, sensors and electronics.

Peat Water Purification by Hydroxyapatite (HAp) Synthesized from Waste Pensi (Corbicula moltkiana) Shells

NASA Astrophysics Data System (ADS)

Fajri Alif, Matlal; Aprillia, Wandha; Arief, Syukri

2018-01-01

Hydroxyapatite (HAP) were synthesized from Pensi (Corbicula moltkiana) sheels by hydrothermal method and used as adsorbent for peat water purification. Batch adsorption experiments were performed to investigate the effects of various factors such as contact time, adsorbent dosage, and pH. The obtained materials were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). Results showed that HAP calcined at 900°C (HAP900) and 1000°C (HAP1000) have a poorly crystalline shape. HAP900 also contain Tetracalsium Phosphate (TTCP) with a Ca/P molar ratio 2.18, while HAP 1000 contain HAp with a Ca/P molar ratio 1.67. Optimum condition for peat water purification with HAP900 and HAP1000 were both achieved at 1 hours, 1 grams adsorben mass at pH 2. SEM micrographs show that after purification, the surface of HAP were covered by organic compounds from peat water.

Synthesis of Zinc Oxide Nanoparticles using Anthocyanin as a Capping Agent

NASA Astrophysics Data System (ADS)

Septiani, N. L. W.; Yuliarto, B.; Iqbal, M.; Nugraha

2017-05-01

Zinc Oxide nanoparticles have been successfully synthesized by utilizing anthocyanin as a capping agent by thermal decomposition of precursor route. The influence of the high and low concentrations of the anthocyanin to the shape and size of ZnO was investigated in this work. The anthocyanin was obtained from Indonesia black rice extract with methanol as a solvent. The crystallinity and morphology properties were characterized by X-Ray Diffractometer (XRD), and Scanning Electron Microscope (SEM), respectively. XRD result showed that ZnO was formed with good crystallinity without any second phase and had a hexagonal wurtzite crystal structure. SEM result revealed that ZnO with a low concentration of anthocyanin has a spherical shape with a uniform size of about 16 nm while ZnO with a high concentration of anthocyanin has a rod-like shape. The size of spherical ZnO in this work is smaller than ZnO from the same method of synthesis without anthocyanin (~30 nm).

Study on structure and morphology (Boehmeria nivea) in the irregular and regular parts of the fiber after biodegumming

NASA Astrophysics Data System (ADS)

Wulandari, A. P.; Septarini, D.; Zainuddin, A.

2017-05-01

Ramie is a natural fiber that is very potential to be developed in Indonesia. Decorticated-fiber which has been known as china grass produce different structures irregular part but shows a long straight section in the middle. This study aims to determine differences in chemical components, morphology and microstructure of two different parties after biodegumming process. China grass has been processed to remove gum using pectinolytic fungus. The microstructure of the treated was further tested by Fourier Transform InfraRed (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM). The FTIR study indicated that during the biodegumming process, chemical bonding of non-cellulose components most removed by the activity of pectinase from the fungus. XRD analysis reflects an increase in the crystallinity of the fiber after biodegumming. Scanning electron microscopy (SEM) was used to confirm a reduction in the size of the fiber after biodegumming either in the irregular and regular part of the fiber after biodegumming.

Shock induced reaction of Ni/Al nanopowder mixture.

PubMed

Meng, C M; Wei, J J; Chen, Q Y

2012-11-01

Nanopowder Ni/Al mixture (mixed in Al:Ni = 2:1 stoichiometry) was shock compressed by employing single and two-stage light gas gun. The particle size of Al and Ni are 100-200 nm and 50-70 nm respectively, morphologies of Al and Ni are sphere like either. Recovered product was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. According to the XRD spectrum, the mixed powder undergo complete reaction under shock compression, reaction product consist of Ni2Al3, NiAl and corundum structure Al2O3 compound. Grain size of Ni-Al compound is less than 100 nm. With the shock pressure increasing, the ratio of Ni2Al3 decreased obviously. The corundum crystal size is 400-500 nm according to the SEM observation. The results of shock recovery experiments and analysis show that the threshold pressure for reaction of nano size powder Ni/Al mixture is much less than that of micro size powder.

Physicochemical characterization of chitosan/nylon6/polyurethane foam chemically cross-linked ternary blends.

PubMed

Jayakumar, S; Sudha, P N

2013-03-15

Chitosan/nylon6/polyurethane foam (CS/Ny6/PUF) ternary blend was prepared and chemically cross-linked with glutaraldehyde. Structural, thermal and morphological studies were performed for the prepared ternary blends. Characterizations of the ternary blends were investigated by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM). The FTIR results showed that the strong intermolecular hydrogen bonds took place between CS, Ny6 and PUF. TGA and DSC studies reveal that the thermal stability of the blend is enhanced by glutaraldehyde as crosslinking agent. Results of XRD indicated that the relative crystalline of pure CS film was reduced when the polymeric network was reticulated by glutaraldehyde. Finally, the results of scanning electron microscopy (SEM) indicated that the morphology of the blend is rough and heterogeneous, further it confirms the interaction between the functional groups of the blend components. Copyright © 2012 Elsevier B.V. All rights reserved.

Facile synthesis of Co3O4 hexagonal plates by flux method

NASA Astrophysics Data System (ADS)

Han, Ji-Long; Meng, Qing-Fen; Gao, Sheng-Li

2018-01-01

Using a novel flux method, a hexagonal plate of Co3O4 was directly synthesized. In this method, CoCl2·6H2O, NaOH, and the cosolvent H3BO3 were heated to 750 °C for 2 h in a corundum crucible. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high-resolution transmission electron microscope (HRTEM). Furthermore, XRD studies indicated that the product consisted of a cubic phase of Co3O4, and the phase existed in a completely crystalline form. Then, SEM results indicated that these hexagonal plates tiered up and they had diameters in the range of 2-10 μm. According to the results of SAED and HRTEM analyses, the interlayer spacing was about 0.24 nm, which corresponds to the interlayer distance of (3 1 1) crystal plane of cubic Co3O4.

Phase Equilibria and Magnetic Phases in the Ce-Fe-Co-B System

PubMed Central

Wang, Tian; Kevorkov, Dmytro; Medraj, Mamoun

2016-01-01

Ce-Fe-Co-B is a promising system for permanent magnets. A high-throughput screening method combining diffusion couples, key alloys, Scanning Electron Microscope/Wavelength Dispersive X-ray Spectroscope (SEM/WDS), and Magnetic Force Microscope (MFM) is used in this research to understand the phase equilibria and to explore promising magnetic phases in this system. Three magnetic phases were detected and their homogeneity ranges were determined at 900 °C, which were presented by the formulae: Ce2Fe14−xCoxB (0 ≤ x ≤ 4.76), CeCo4−xFexB (0 ≤ x ≤ 3.18), and Ce3Co11−x FexB4 (0 ≤ x ≤ 6.66). The phase relations among the magnetic phases in this system have been studied. Ce2(Fe, Co)14B appears to have stronger magnetization than Ce(Co, Fe)4B and Ce3(Co, Fe)11B4 from MFM analysis when comparing the magnetic interactions of selected key alloys. Also, a non-magnetic CeCo12−xFexB6 (0 ≤ x ≤ 8.74) phase was detected in this system. A boron-rich solid solution with Ce13FexCoyB45 (32 ≤ x ≤ 39, 3 ≤ y ≤ 10) chemical composition was also observed. However, the crystal structure of this phase could not be found in the literature. Moreover, ternary solid solutions ε1 (Ce2Fe17−xCox (0 ≤ x ≤ 12.35)) and ε2 (Ce2Co17−xFex (0 ≤ x ≤ 3.57)) were found to form between Ce2Fe17 and Ce2Co17 in the Ce-Fe-Co ternary system at 900 °C. PMID:28772374

Synthesis, characterization, and hydrogen uptake studies of magnesium nanoparticles by solution reduction method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rather, Sami ullah, E-mail: rathersami@gmail.com

2014-12-15

Graphical abstract: X-ray diffraction (XRD) pattern of magnesium nanoparticles synthesized by solution reduction method with and without TOPO. - Highlights: • Simple and convenient method of preparing Mg nanoparticles. • Characterized by XRD, SEM, FESEM and TEM. • Trioctylphosphine oxide offers a greater control over the size of the particles. • Hydrogen uptake of samples at different temperatures and pressure of 4.5 MPa. - Abstract: Facile and simple, surfactant-mediated solution reduction method was used to synthesize monodisperse magnesium nanoparticles. Little amount of magnesium oxide nanoparticles were also formed due to the presence of TOPO and easy oxidation of magnesium, eventhough,more » all precautions were taken to avoid oxidation of the sample. Precise size control of particles was achieved by carefully varying the concentration ratio of two different types of surfactants, – trioctylphosphine oxide and hexadecylamine. Recrystallized magnesium nanoparticle samples with and without TOPO were analyzed by X-ray diffraction, scanning electron microscope, field emission scanning electron microscope, and transmission electron microscope. The peak diameters of particles were estimated from size distribution analysis of the morphological data. The particles synthesized in the presence and absence of TOPO found to have diameters 46.5 and 34.8 nm, respectively. This observed dependence of particle size on the presence of TOPO offers a convenient method to control the particle size by simply using appropriate surfactant concentrations. Exceptional enhancement in hydrogen uptake and kinetics in synthesized magnesium nanoparticles as compared to commercial magnesium sample was due to the smaller particle size and improved morphology. Overall hydrogen uptake not affected by the little variation in particle size with and without TOPO.« less

Guided self-assembly of nanostructured titanium oxide

NASA Astrophysics Data System (ADS)

Wang, Baoxiang; Rozynek, Zbigniew; Fossum, Jon Otto; Knudsen, Kenneth D.; Yu, Yingda

2012-02-01

A series of nanostructured titanium oxide particles were synthesized by a simple wet chemical method and characterized by means of small-angle x-ray scattering (SAXS)/wide-angle x-ray scattering (WAXS), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal analysis, and rheometry. Tetrabutyl titanate (TBT) and ethylene glycol (EG) can be combined to form either TiOx nanowires or smooth nanorods, and the molar ratio of TBT:EG determines which of these is obtained. Therefore, TiOx nanorods with a highly rough surface can be obtained by hydrolysis of TBT with the addition of cetyl-trimethyl-ammonium bromide (CTAB) as surfactant in an EG solution. Furthermore, TiOx nanorods with two sharp ends can be obtained by hydrolysis of TBT with the addition of salt (LiCl) in an EG solution. The AFM results show that the TiOx nanorods with rough surfaces are formed by the self-assembly of TiOx nanospheres. The electrorheological (ER) effect was investigated using a suspension of titanium oxide nanowires or nanorods dispersed in silicone oil. Oil suspensions of titanium oxide nanowires or nanorods exhibit a dramatic reorganization when submitted to a strong DC electric field and the particles aggregate to form chain-like structures along the direction of applied electric field. Two-dimensional SAXS images from chains of anisotropically shaped particles exhibit a marked asymmetry in the SAXS patterns, reflecting the preferential self-assembly of the particles in the field. The suspension of rough TiOx nanorods shows stronger ER properties than that of the other nanostructured TiOx particles. We find that the particle surface roughness plays an important role in modification of the dielectric properties and in the enhancement of the ER effect.

High-resolution 3D analyses of the shape and internal constituents of small volcanic ash particles: The contribution of SEM micro-computed tomography (SEM micro-CT)

NASA Astrophysics Data System (ADS)

Vonlanthen, Pierre; Rausch, Juanita; Ketcham, Richard A.; Putlitz, Benita; Baumgartner, Lukas P.; Grobéty, Bernard

2015-02-01

The morphology of small volcanic ash particles is fundamental to our understanding of magma fragmentation, and in transport modeling of volcanic plumes and clouds. Until recently, the analysis of 3D features in small objects (< 250 μm) was either restricted to extrapolations from 2D approaches, partial stereo-imaging, or CT methods having limited spatial resolution and/or accessibility. In this study, an X-ray computed-tomography technique known as SEM micro-CT, also called 3D X-ray ultramicroscopy (3D XuM), was used to investigate the 3D morphology of small volcanic ash particles (125-250 μm sieve fraction), as well as their vesicle and microcrystal distribution. The samples were selected from four stratigraphically well-established tephra layers of the Meerfelder Maar (West Eifel Volcanic Field, Germany). Resolution tests performed on a Beametr v1 pattern sample along with Monte Carlo simulations of X-ray emission volumes indicated that a spatial resolution of 0.65 μm was obtained for X-ray shadow projections using a standard thermionic SEM and a bulk brass target as X-ray source. Analysis of a smaller volcanic ash particle (64-125 μm sieve fraction) showed that features with volumes > 20 μm3 (~ 3.5 μm in diameter) can be successfully reconstructed and quantified. In addition, new functionalities of the Blob3D software were developed to allow the particle shape factors frequently used as input parameters in ash transport and dispersion models to be calculated. This study indicates that SEM micro-CT is very well suited to quantify the various aspects of shape in fine volcanic ash, and potentially also to investigate the 3D morphology and internal structure of any object < 0.1 mm3.

Near-infrared quantum cutting in Yb3+ ion doped strontium vanadate

NASA Astrophysics Data System (ADS)

Sawala, N. S.; Bajaj, N. S.; Omanwar, S. K.

2016-05-01

The materials Sr3-x(VO4)2:xYb were successfully synthesized by co-precipitation method varying the concentration of Yb3+ ions from 0 to 0.06 mol. It was characterize by powder X-ray powder diffraction (XRD) and surface morphology was studied by scanning electronic microscope (SEM). The photoluminescence (PL) properties were studied by spectrophotometers in near infra red (NIR) and ultra violet visible (UV-VIS) region. The Yb3+ ion doped tristrontium vanadate (Sr3(VO4)2) phosphors that can convert a photon of UV region (349 nm) into photons of NIR region (978, 996 and 1026 nm). Hence this phosphor could be used as a quantum cutting (QC) luminescent convertor in front of crystalline silicon solar cell (c-Si) panels to reduce thermalization loss due to spectral mismatch of the solar cells. The theoretical value of quantum efficiency (QE) was calculated from steady time decay measurement and the maximum efficiency approached up to 144.43%. The Sr(3-x) (VO4)2:xYb can be potentiality used for betterment of photovoltaic (PV) technology.

Microstructure and mineral composition of dental enamel of permanent and deciduous teeth.

PubMed

De Menezes Oliveira, Maria Angélica Hueb; Torres, Carolina Paes; Gomes-Silva, Jaciara Miranda; Chinelatti, Michelle Alexandra; De Menezes, Fernando Carlos Hueb; Palma-Dibb, Regina Guenka; Borsatto, Maria Cristina

2010-05-01

This study evaluated and compared in vitro the microstructure and mineral composition of permanent and deciduous teeth's dental enamel. Sound third molars (n = 12) and second primary molars (n = 12) were selected and randomly assigned to the following groups, according to the analysis method performed (n = 4): Scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Energy dispersive X-ray spectrometer (EDS). Qualitative and quantitative comparisons of the dental enamel were done. The microscopic findings were analyzed statistically by a nonparametric test (Kruskal-Wallis). The measurements of the prisms number and thickness were done in SEM photomicrographs. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Chemical phases present in both types of teeth were observed by the XRD analysis. The mean thickness measurements observed in the deciduous teeth enamel was 1.14 mm and in the permanent teeth enamel was 2.58 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enamel-dentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The percentage of Ca and P was higher in the permanent teeth enamel. The primary enamel structure showed a lower level of Ca and P, thinner thickness and higher numerical density of rods. (c) 2009 Wiley-Liss, Inc.

The effect of gradient boracic polyanion-doping on structure, morphology, and cycling performance of Ni-rich LiNi0.8Co0.15Al0.05O2 cathode material

NASA Astrophysics Data System (ADS)

Chen, Tao; Li, Xiang; Wang, Hao; Yan, Xinxiu; Wang, Lei; Deng, Bangwei; Ge, Wujie; Qu, Meizhen

2018-01-01

A gradient boracic polyanion-doping method is applied to Ni-rich LiNi0.8Co0.15Al0.05O2 (NCA) cathode material in this study to suppress the capacity/potential fade during charge-discharge cycling. Scanning electron microscope (SEM) results show that all samples present spherical morphology and the secondary particle size increases with increasing boron content. X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) results demonstrate that boracic polyanions are successfully introduced into the bulk material and more enriched in the outer layer. XPS analysis further reveals that the valence state of Ni3+ is partly reduced to Ni2+ at the surface due to the incorporation of boracic polyanions. From the electrochemical measurements, B0.015-NCA electrode exhibits excellent cycling performance, even at high potential and elevated temperature. Moreover, the SEM images illustrate the presence of cracks and a thick SEI layer on pristine particles after 100 cycles at high temperature, while the B0.015-NCA particles show an intact structure and thin SEI layer. Electrochemical impedance spectroscopy confirms that the boracic polyanion doping could hinder the impedance increase during cycling at elevated temperature. These results clearly indicate that the gradient boracic polyanion-doping contributes to the remarkable enhancement of structure stability and cycling performance of NCA.

Study on the sulfidation behavior of smithsonite

NASA Astrophysics Data System (ADS)

Wu, Dandan; Wen, Shuming; Deng, Jiushuai; Liu, Jian; Mao, Yingbo

2015-02-01

Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pHIEP of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, CS in the solution declined from 1000 × 10-6 mol/L to 1.4 × 10-6 mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S2- and CO32- ions.

Fine Structure in Multi-Phase Zr8Ni21-Zr7Ni10-Zr2Ni7 Alloy Revealed by Transmission Electron Microscope

PubMed Central

Shen, Haoting; Bendersky, Leonid A.; Young, Kwo; Nei, Jean

2015-01-01

The microstructure of an annealed alloy with a Zr8Ni21 composition was studied by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The presence of three phases, Zr8Ni21, Zr2Ni7, and Zr7Ni10, was confirmed by SEM/X-ray energy dispersive spectroscopy compositional mapping and TEM electron diffraction. Distribution of the phases and their morphology can be linked to a multi-phase structure formed by a sequence of reactions: (1) L → Zr2Ni7 + L’; (2) peritectic Zr2Ni7 + L’ → Zr2Ni7 + Zr8Ni21 + L”; (3) eutectic L” → Zr8Ni21 + Zr7Ni10. The effect of annealing at 960 °C, which was intended to convert a cast structure into a single-phase Zr8Ni21 structure, was only moderate and the resulting alloy was still multi-phased. TEM and crystallographic analysis of the Zr2Ni7 phase show a high density of planar (001) defects that were explained as low-energy boundaries between rotational variants and stacking faults. The crystallographic features arise from the pseudo-hexagonal structure of Zr2Ni7. This highly defective Zr2Ni7 phase was identified as the source of the broad X-ray diffraction peaks at around 38.4° and 44.6° when a Cu-K was used as the radiation source. PMID:28793460

Focused Ion Beam (FIB) combined with SEM (FIB/SEM) and TEM: Advanced tools for nano-analysis in Geosciences

NASA Astrophysics Data System (ADS)

Wirth, R.; Morales, L. G.

2011-12-01

Focused ion beam (FIB) techniques have been successfully applied to the preparation of site-specific electron transparent membranes for transmission electron microscopy (TEM) investigations in Geosciences since several years. For example, systematic TEM studies of nano-inclusions in diamond foils prepared with FIB have improved our knowledge on diamond formation. However, FIB is not exclusively used for sample preparation for TEM application because it has been proved that one and the same TEM foil can also be used for Synchrotron IR, Synchrotron X-Ray fluorescence (XRF), scanning transmission X-Ray microscopy (STXM) and NanoSIMS analysis. In addition, FIB milling turned out to be very useful for sample preparation of Brillouin scattering experiments and has a strong potential for preparation of highly-polished, micrometer-scale samples. However, a real break through in FIB application was achieved combining a Ga-ion source of the FIB with an electron source of a scanning electron microscope (SEM) in one single instrument. The combination of FIB/SEM renders access to the third dimension of the sample possible. A cavity normal to the sample surface is sputtered with Ga-ions and this newly created inner surface is imaged with the electron beam. Alternating slicing and viewing along these cavities allow the acquisition of a sequence of images that allows the observation in 3 dimensions. Recently, this technique has been successfully applied to image the structure of grain or phase boundaries in metamorphic rocks as well as micro- and nanoporosity in shales, but its applicability goes far beyond these few examples. Combining slicing and viewing with X-Ray and electron backscatter diffraction (EBSD) analysis can provide 3D elemental mapping and 3D crystallographic orientation mapping of crystalline materials. Combined FIB/SEM devices also facilitate the preparation of substantially thinner and cleaner TEM foils (approximately 30 nm) because electron beam imaging controls the progress of the sputtering process without sputtering the sample during imaging. Electron induce sputtering is substantially smaller than ion induced sputtering. Finally, the amorphous layers created by Ga-ion sputtering and Ga-ion implantation can be removed from the foil surfaces by subsequent argon ion bombardment under a low angle of incidence and low acceleration voltage thus permitting TEM high-resolution imaging and electron energy-loss spectroscopy (EELS). Additionally, ultra-thin foils have the advantage that they are electron transparent even at 30 keV, the common operational voltage of a SEM. Therefore the electron column of the FIB/SEM system can be used as a TEM at low voltage and images can be made either in bright-field, dark field and through a high-angle annular dark field (HAADF) detector. The HAADF detector provides information about the chemical composition of the specimen with high spatial resolution because it is Z-contrast sensitive.

Relative merits and limiting factors for x-ray and electron microscopy of thick, hydrated organic materials

DOE PAGES

Du, Ming; Jacobsen, Chris

2017-10-07

Electron and x-ray microscopes allow one to image the entire, unlabeled structure of hydrated materials at a resolution well beyond what visible light microscopes can achieve. However, both approaches involve ionizing radiation, so that radiation damage must be considered as one of the limits to imaging. Drawing upon earlier work, we describe here a unified approach to estimating the image contrast (and thus the required exposure and corresponding radiation dose) in both x-ray and electron microscopy. This approach accounts for factors such as plural and inelastic scattering, and (in electron microscopy) the use of energy filters to obtain so-called "zeromore » loss" images. As expected, it shows that electron microscopy offers lower dose for specimens thinner than about 1 mu m (such as for studies of macromolecules, viruses, bacteria and archaebacteria, and thin sectioned material), while x-ray microscopy offers superior characteristics for imaging thicker specimen such as whole eukaryotic cells, thick-sectioned tissues, and organs. The required radiation dose scales strongly as a function of the desired spatial resolution, allowing one to understand the limits of live and frozen hydrated specimen imaging. Lastly, we consider the factors limiting x-ray microscopy of thicker materials, suggesting that specimens as thick as a whole mouse brain can be imaged with x-ray microscopes without significant image degradation should appropriate image reconstruction methods be identified.« less

Relative merits and limiting factors for x-ray and electron microscopy of thick, hydrated organic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Ming; Jacobsen, Chris

Electron and x-ray microscopes allow one to image the entire, unlabeled structure of hydrated materials at a resolution well beyond what visible light microscopes can achieve. However, both approaches involve ionizing radiation, so that radiation damage must be considered as one of the limits to imaging. Drawing upon earlier work, we describe here a unified approach to estimating the image contrast (and thus the required exposure and corresponding radiation dose) in both x-ray and electron microscopy. This approach accounts for factors such as plural and inelastic scattering, and (in electron microscopy) the use of energy filters to obtain so-called "zeromore » loss" images. As expected, it shows that electron microscopy offers lower dose for specimens thinner than about 1 mu m (such as for studies of macromolecules, viruses, bacteria and archaebacteria, and thin sectioned material), while x-ray microscopy offers superior characteristics for imaging thicker specimen such as whole eukaryotic cells, thick-sectioned tissues, and organs. The required radiation dose scales strongly as a function of the desired spatial resolution, allowing one to understand the limits of live and frozen hydrated specimen imaging. Lastly, we consider the factors limiting x-ray microscopy of thicker materials, suggesting that specimens as thick as a whole mouse brain can be imaged with x-ray microscopes without significant image degradation should appropriate image reconstruction methods be identified.« less

Comparing plasma and X-ray exposure and identifying vulnerable cell parts

NASA Astrophysics Data System (ADS)

Graham, Bill

2012-10-01

Here two issues in plasma medicine that are being addressed in a collaboration between the Centre of Plasma Physics and the School of Pharmacy at Queen's University Belfast and the Plasma Institute at York University UK will be discussed. Recent measurements of the interaction of plasmas created directly in DMEM cell medium and MDAMB-231, a human breast cancer cell line, showed evidence of reduced cell viability and of DNA damage. The same set of experiments were undertaken but with X-ray exposure. A correlation of the dependence on plasma exposure time and X-ray dose was observed which might point the way to dose definition in plasma medicine. We have also been working to identify the cell parts most vulnerable to plasma exposure. In this study a 10 kHz atmospheric pressure non-thermal plasma jet, operating in He/0.5%O2 and characterized to determine the behavior of many of the plasma species, was incident onto the surface of media containing either bacterial strains, in their planktonic and biofilm forms, or isolated bacterial plasmid DNA. The results of measurements to look for changes in plasmid structural conformation, rates of single and double strand breaks, the catalytic activity of certain bacterial enzymes, the peroxidation of lipid content of the bacterial cells, the leakage of ATP and Scanning Electron Microscope (SEM) images will be discussed.

Microstructure, ferromagnetic and photoluminescence properties of ITO and Cr doped ITO nanoparticles using solid state reaction

NASA Astrophysics Data System (ADS)

Babu, S. Harinath; Kaleemulla, S.; Rao, N. Madhusudhana; Rao, G. Venugopal; Krishnamoorthi, C.

2016-11-01

Indium-tin-oxide (ITO) (In0.95Sn0.05)2O3 and Cr doped indium-tin-oxide (In0.90Sn0.05Cr0.05)2O3 nanoparticles were prepared using simple low cost solid state reaction method and characterized by different techniques to study their structural, optical and magnetic properties. Microstructures, surface morphology, crystallite size of the nanoparticles were studied using X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM). From these methods it was found that the particles were about 45 nm. Chemical composition and valence states of the nanoparticles were studied using energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (XPS). From these techniques it was observed that the elements of indium, tin, chromium and oxygen were present in the system in appropriate ratios and they were in +3, +4, +3 and -2 oxidation states. Raman studies confirmed that the nanoparticle were free from unintentional impurities. Two broad emission peaks were observed at 330 nm and 460 nm when excited wavelength of 300 nm. Magnetic studies were carried out at 300 K and 100 K using vibrating sample magnetometer (VSM) and found that the ITO nanoparticles were ferromagnetic at 100 K and 300 K. Where-as the room temperature ferromagnetism completely disappeared in Cr doped ITO nanoparticles at 100 K and 300 K.

Synthesis and surface characterization of alumina-silica-zirconia nanocomposite ceramic fibres on aluminium at room temperature

NASA Astrophysics Data System (ADS)

Mubarak Ali, M.; Raj, V.

2010-04-01

Alumina-silica-zirconia nanocomposite (ASZNC) ceramic fibres were synthesized by conventional anodization route. Scanning Electron Microscopy (SEM), Atomic Force microscopy (AFM), X-Ray Diffraction (XRD) and Energy Dispersive X-Ray spectroscopy (EDAX) were used to characterize the morphology and crystalloid structure of ASZNC fibres. Current density (DC) is one of the important parameters to get the alumina-silica-zirconia nanocomposite (ASZNC) ceramic fibres by this route. Annealing of the films exhibited a drastic change in the properties due to improved crystallinity. The root mean square roughness of the sample observed from atomic force microscopic analysis is about 71.5 nm which is comparable to the average grain size of the coatings which is about 72 nm obtained from X-Ray diffraction. The results indicate that, the ASZNC fibres are arranged well in the nanostructure. The thickness of the coating increased with the anodizing time, but the coatings turned rougher and more porous. At the initial stage the growth of ceramic coating increases inwards to the metal substrate and outwards to the coating surface simultaneously. Subsequently, it mainly grows towards the metal substrate and the density of the ceramic coating increases gradually, which results in the decrease of the total thickness as anodizing time increases. This new approach of preparing ASZNC ceramic fibres may be important in applications ranging from gas sensors to various engineering materials.

Role of manganese dioxide in the recovery of oxide-sulphide zinc ore.

PubMed

Yang, Kun; Zhang, Libo; Zhu, Xingcai; Peng, Jinhui; Li, Shiwei; Ma, Aiyuan; Li, Haoyu; Zhu, Fei

2018-02-05

In this article, the role of MnO 2 in the recovery of oxide-sulphide zinc ore discussed. Through adopting various modern analysis techniques (such as X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope, energy dispersive X-ray analysis, and fourier transform infrared spectroscopy), the function and mechanism of MnO 2 during the phase transformation process is found out. Thermodynamic mechanisms involved in the phase transformation process with or without addition of manganese dioxide investigated by exploiting the Equilib module of FactSage. What's more, XRD patterns, XPS spectra and SEM-EDAX analyses of zinc calcines verify well the calculations of FactSage. Results reveal that the addition of MnO 2 will produce an aggregation of ZnMn 2 O 4 , a valuable energy material, while roasting on its own, results in generating undesirable Zn 2 SiO 4 , the oxidation degree being relatively low. Moreover, XRD pattern of zinc calcine and FT-IR spectrum of yellow product collected in the calcination process prove that the sulphur-fixing value of the additive MnO 2 , which can promote transforming to the elemental sulphur. The volatile S can be collected through a simple guiding device. In this process, the emission of SO 2 effectively avoids, thus MnO 2 deems as a potential additive in the recovery of oxide-sulphide zinc ore. Copyright © 2017. Published by Elsevier B.V.

Synthesis of novel CeO2-BiVO4/FAC composites with enhanced visible-light photocatalytic properties.

PubMed

Zhang, Jin; Wang, Bing; Li, Chuang; Cui, Hao; Zhai, Jianping; Li, Qin

2014-09-01

To utilize visible light more effectively in photocatalytic reactions, a fly ash cenosphere (FAC)-supported CeO2-BiVO4 (CeO2-BiVO4/FAC) composite photocatalyst was prepared by modified metalorganic decomposition and impregnation methods. The physical and photophysical properties of the composite have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and UV-Visible diffuse reflectance spectra. The XRD patterns exhibited characteristic diffraction peaks of both BiVO4 and CeO2 crystalline phases. The XPS results showed that Ce was present as both Ce(4+) and Ce(3+) oxidation states in CeO2 and dispersed on the surface of BiVO4 to constitute a p-n heterojunction composite. The absorption threshold of the CeO2-BiVO4/FAC composite shifted to a longer wavelength in the UV-Vis absorption spectrum compared to the pure CeO2 and pure BiVO4. The composites exhibited enhanced photocatalytic activity for Methylene Blue (MB) degradation under visible light irradiation. It was found that the 7.5wt.% CeO2-BiVO4/FAC composite showed the highest photocatalytic activity for MB dye wastewater treatment. Copyright © 2014. Published by Elsevier B.V.

Applications of synchrotron x-ray diffraction topography to fractography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bilello, J.C.

1983-01-01

Fractographs have been taken using a variety of probes each of which produces different types of information. Methods which have been used to examine fracture surfaces include: (a) optical microscopy, particularly interference contrast methods, (b) scanning electron microscopy (SEM), (c) SEM with electron channelling, (d) SEM with selected-area electron channelling, (e) Berg-Barrett (B-B) topography, and now (f) synchrotron x-radiation fractography (SXRF). This review concentrated on the role that x-ray methods can play in such studies. In particular, the ability to nondestructively assess the subsurface microstructure associated with the fracture to depths of the order of 5 to 10 ..mu..m becomesmore » an important attribute for observations of a large class of semi-brittle metals, semiconductors and ceramics.« less

A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source.

PubMed

Horne, S F; Silterra, J; Holber, W

2009-01-01

Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported.

A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source

PubMed Central

Silterra, J; Holber, W

2009-01-01

Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported. PMID:20198115

Surface Modification Technique of Cathode Materials for LI-ION Battery

NASA Astrophysics Data System (ADS)

Jia, Yongzhong; Han, Jinduo; Jing, Yan; Jin, Shan; Qi, Taiyuan

Cathode materials for Li-ion battery LiMn2O4 and LiCo0.1Mn1.9O4 were prepared by soft chemical method. Carbon, which was made by decomposing organic compounds, was used as modifying agent. Cathode material matrix was mixed with water solution that had contained organic compound such as cane sugar, soluble amylum, levulose et al. These mixture were reacted at 150 200 °C for 0.5 4 h in a Teflon-lined autoclave to get a series of homogeneously C-coated cathode materials. The new products were analyzed by X-ray diffraction (XRD) and infrared (IR). Morphology of cathode materials was characterized by scanning electron microscope (SEM) and transition electron microscope (TEM). The new homogeneously C-coated products that were used as cathode materials of lithium-ion battery had good electrochemical stability and cycle performance. This technique has free-pollution, low cost, simpleness and easiness to realize the industrialization of the cathode materials for Li-ion battery.

Characterization of the Micro-Abrasive Wear in Coatings of TaC-HfC/Au for Biomedical Implants

PubMed Central

Guzmán, Pablo; Yate, Luis; Sandoval, Mercy; Caballero, Jose

2017-01-01

The object of this work was the deposition of a Ta-Hf-C thin film with a gold interlayer on stainless steel, via the physical vapor deposition (PVD) technique, in order to evaluate the properties of different systems subjected to micro-abrasive wear phenomena generated by alumina particles in Ringer's solution. The surface characterization was performed using a scanning electron microscope (SEM) and atomic force microscope (AFM). The crystallographic phases exhibited for each coating were obtained by X-ray diffraction (XRD). As a consequence of modifying the composition of Ta-Hf there was evidence of an improvement in the micro-abrasive wear resistance and, for each system, the wear constants that confirm the enhancement of the surface were calculated. Likewise, these surfaces can be bioactive, generating an alternative to improve the biological fixation of the implants, therefore, the coatings of TaC-HfC/Au contribute in the development of the new generation of orthopedic implants. PMID:28773207

Synthesis of SnO2 and Ag Nanoparticles from Electronic Wastes with the Assistance of Ultrasound and Microwaves

NASA Astrophysics Data System (ADS)

Cerchier, Pietrogiovanni; Dabalà, Manuele; Brunelli, Katya

2017-09-01

In this work, SnO2 and Ag nanoparticles were produced with a raw material nitric acid solution, which came from the leaching of printed circuit boards. First, a precursor of tin oxide was precipitated from the nitric acid solution by three different techniques: (I) conventional heating, (II) microwave irradiation, and (III) ultrasound treatment. Second, this precursor was transformed into tin oxide nanoparticles by heat treatment in a furnace. Third, hydrochloric acid was added to the nitric acid solution to induce the precipitation of silver chloride. Fourth, silver chloride was reduced to metallic silver nanoparticles in an ammonia solution using glucose syrup as both the reducing agent and the capping agent. The reduction reaction was carried out through (I) conventional heating, (II) microwave irradiation, and (III) ultrasound treatment. The nanoparticles were characterized by scanning electron microscope (SEM), x-ray diffractometer (XRD), infrared (IR)-spectroscopy, transmission electron microscope (TEM), ultraviolet (UV)-spectroscopy, and laser diffraction particle size analyzer.

Effect of phase transformation on optical and dielectric properties of zirconium oxide nanoparticles

NASA Astrophysics Data System (ADS)

Chintaparty, Rajababu; Palagiri, Bhavani; Reddy Nagireddy, Ramamanohar; subbha Reddy Imma Reddy, Venkata

2015-09-01

Zirconium oxide nanoparticle (ZrO2) is synthesized by the hydrothermal method at different calcination temperatures. The structural analysis is carried out by X-ray diffraction and Raman spectra. The sample prepared at 400 °C and 1100 °C showed the cubic and monoclinic phase, respectively, and the sample calcined at 600 °C and 800 °C showed the mixed phase with co-existence of cubic and monoclinic phases. Furthermore, the morphology and particle size of these samples were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. The band gap estimated from UV-Vis spectra of ZrO2 (zirconia) nanocrystalline materials calcined at different temperatures from 400 °C to 1100 °C was in the range of 2.6-4.2 eV. The frequency dependence of dielectric constant and dielectric loss was investigated at room temperature. The low frequency region of dielectric constant is attributed to space charge effects.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Shan, E-mail: coralgao@hotmail.com; Engineering Ceramics Key Laboratory of Shandong Province, Shandong University, Jinan 250061; Sun, Kangning, E-mail: sunkangning@sdu.edu.cn

Highlights: ► We succeeded in synthesizing hydroxyapatite nano fibers by a chemical method. ► The reaction temperature is only 90 °C. ► The synthetic hydroxyapatite nano fiber is single crystal. - Abstract: We report a novel chemical precipitation route for the synthesis of hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, HA) fibers using surfactants as templates. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) reveal the characteristic peaks of HA. Transmission electron microscope (TEM) and high-resolution TEM revealed the nano structure, crystallinity and morphology of the HA fibers. The morphology of the HA fibers after calcinations were characterized bymore » scanning electron microscope (SEM). Br{sup −} ions were quickly replaced by the excess PO{sub 4}{sup 3−} ions in the solution after the addition of cetyltrime-thylammonium bromide (CTAB). Meanwhile, CTAB formed a rod-like micelles. Precursors reacted with PO{sub 4}{sup 3−} at the surface of CTAB micelles and finally formed the nanofiber structure.« less

Investigation of argon ion sputtering on the secondary electron emission from gold samples

NASA Astrophysics Data System (ADS)

Yang, Jing; Cui, Wanzhao; Li, Yun; Xie, Guibai; Zhang, Na; Wang, Rui; Hu, Tiancun; Zhang, Hongtai

2016-09-01

Secondary electron (SE) yield, δ, is a very sensitive surface property. The values of δ often are not consistent for even identical materials. The influence of surface changes on the SE yield was investigated experimentally in this article. Argon ion sputtering was used to remove the contamination from the surface. Surface composition was monitored by X-ray photoelectron spectroscopy (XPS) and surface topography was scanned by scanning electron microscope (SEM) and atomic force microscope (AFM) before and after every sputtering. It was found that argon sputtering can remove contamination and roughen the surface. An ;equivalent work function; is presented in this thesis to establish the relationship between SE yield and surface properties. Argon ion sputtering of 1.5keV leads to a significant increase of so called ;work function; (from 3.7 eV to 6.0 eV), and a decrease of SE yield (from 2.01 to 1.54). These results provided a new insight into the influence of surface changes on the SE emission.

Photocatalytic degradation of methyl orange and bromophenol blue dyes in water using sol-gel synthesized TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Dhanalakshmi, J.; Pathinettam Padiyan, D.

2017-09-01

TiO2 nanoparticles were prepared by a sol-gel method using titanium tetra isopropoxide as a precursor. The structural, optical, morphological and electrical properties were studied by x-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), a high resolution scanning electron microscope (HR-SEM), a transmission electron microscope (TEM), Raman analysis, Photoluminescence (PL) and impedance spectroscopy. The XRD and Raman spectra revealed that the synthesized samples are in pure anatase phase with an average crystallite size of 18 nm. Photocatalytic activity of the TiO2 nanoparticles was investigated for the degradation of 10 ppm methyl orange (MO) and bromophenol blue (BPB) dye using 10 mg of catalyst. Anatase TiO2 exhibited the removal of 67.12% and 85.51% of MO and BPB, respectively, within 240 min. The photocatalytic degradation process is explained using pseudo second order kinetics and fits well with the higher correlation coefficient.

Microstructural Study of Micron-Sized Craters Simulating Stardust Impacts in Aluminum 1100 Targets

NASA Technical Reports Server (NTRS)

Leroux, Hugues; Borg, Janet; Troadec, David; Djouadi, Zahia; Horz, Friedrich

2006-01-01

Various microscopic techniques were used to characterize experimental micro- craters in aluminium foils to prepare for the comprehensive analysis of the cometary and interstellar particle impacts in aluminium foils to be returned by the Stardust mission. First, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) were used to study the morphology of the impact craters and the bulk composition of the residues left by soda-lime glass impactors. A more detailed structural and compositional study of impactor remnants was then performed using TEM (Transmission Electron Microscopy), EDS, and electron diffraction methods. The TEM samples were prepared by Focused Ion Beam (FIB) methods. This technique proved to be especially valuable in studying impact crater residues and impact crater morphology. Finally, we also showed that InfraRed microscopy (IR) can be a quick and reliable tool for such investigations. The combination of all of these tools enables a complete microscopic characterization of the craters.

A high selective methanol gas sensor based on molecular imprinted Ag-LaFeO3 fibers.

PubMed

Rong, Qian; Zhang, Yumin; Wang, Chao; Zhu, Zhongqi; Zhang, Jin; Liu, Qingju

2017-09-21

Ag-LaFeO 3 molecularly imprinted polymers (ALMIPs) were fabricated, which provided special recognition sites to methanol. Then ALMIPs fiber 1, fiber 2 and fiber 3 were prepared using filter paper, silk and carbon fibers template, respectively. Based on the observation of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and Nitrogen adsorption surface area analyzer (BET), the structure, morphology and surface area of the fibers were characterized. The ALMIPs fibers (fiber 1, fiber 2 and fiber 3) show excellent selectivity and good response to methanol. The responses to 5 ppm methanol and the optimal operating temperature of ALMIPs fibers are 23.5 and 175 °C (fiber 1), 19.67 and 125 °C (fiber 2), 17.59 and 125 °C (fiber 3), and a lower response (≤10, 3, 2) to other test gases including formaldehyde, acetone, ethanol, ammonia, gasoline and benzene was measured, respectively.

Nano CaCO₃ imprinted starch hybrid polyethylhexylacrylate\\polyvinylalcohol nanocomposite thin films.

PubMed

Prusty, Kalyani; Swain, Sarat K

2016-03-30

Starch hybrid polyethylhexylacrylate (PEHA)/polyvinylalcohol (PVA) nanocomposite thin films are prepared by different composition of nano CaCO3 in aqueous medium. The chemical interaction of nano CaCO3 with PEHA in presence of starch and PVA is investigated by Fourier transforms infrared spectroscopy (FTIR). X-ray diffraction (XRD) is used in order to study the change in crystallite size and d-spacing during the formation of nanocomposite thin film. The surface morphology of nanofilms is studied by scanning electron microscope (SEM). The topology and surface roughness of the films is noticed by atomic force microscope (AFM). The tensile strength, thermal stability and thermal conductivity of films are increased with increase in concentrations of CaCO3 nanopowder. The chemical resistance and biodegradable properties of the nanocomposite thin films are also investigated. The growth of bacteria and fungi in starch hybrid PEHA film is reduced substantially with imprint of nano CaCO3. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of alumina ceramic encapsulation for self-healing materials on thermal barrier coating

NASA Astrophysics Data System (ADS)

Golim, O. P.; Prastomo, N.; Izzudin, H.; Hastuty, S.; Sundawa, R.; Sugiarti, E.; Thosin, K. A. Z.

2018-03-01

Durability of Thermal Barrier Coating or TBC can be optimized by inducing Self-Healing capabilities with intermetallic materials MoSi2. Nevertheless, high temperature operation causes the self-healing materials to become oxidized and lose its healing capabilities. Therefore, a method to introduce ceramic encapsulation for MoSi2 is needed to protect it from early oxidation. The encapsulation process is synthesized through a simple precipitation method with colloidal aluminum hydroxide as precursor and variations on calcination process. Semi-quantitative analysis on the synthesized sample is done by using X-ray diffraction (XRD) method. Meanwhile, qualitative analysis on the morphology of the encapsulation was carried out by using Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FESEM) equipped with dual Focus Ion Beam (FIB). The result of the experiment shows that calcination process significantly affects the final characteristic of encapsulation. The optimum encapsulation process was synthesized by colloidal aluminum hydroxide as a precursor, with a double step calcination process in low pressure until 900 °C.

First Description of Sulphur-Oxidizing Bacterial Symbiosis in a Cnidarian (Medusozoa) Living in Sulphidic Shallow-Water Environments.

PubMed

Abouna, Sylvie; Gonzalez-Rizzo, Silvina; Grimonprez, Adrien; Gros, Olivier

2015-01-01

Since the discovery of thioautotrophic bacterial symbiosis in the giant tubeworm Riftia pachyptila, there has been great impetus to investigate such partnerships in other invertebrates. In this study, we present the occurrence of a sulphur-oxidizing symbiosis in a metazoan belonging to the phylum Cnidaria in which this event has never been described previously. Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) observations and Energy-dispersive X-ray spectroscopy (EDXs) analysis, were employed to unveil the presence of prokaryotes population bearing elemental sulphur granules, growing on the body surface of the metazoan. Phylogenetic assessments were also undertaken to identify this invertebrate and microorganisms in thiotrophic symbiosis. Our results showed the occurrence of a thiotrophic symbiosis in a cnidarian identified as Cladonema sp. This is the first report describing the occurrence of a sulphur-oxidizing symbiosis in a cnidarian. Furthermore, of the two adult morphologies, the polyp and medusa, this mutualistic association was found restricted to the polyp form of Cladonema sp.

Soft X-ray microscope with nanometer spatial resolution and its applications

NASA Astrophysics Data System (ADS)

Wachulak, P. W.; Torrisi, A.; Bartnik, A.; Wegrzynski, L.; Fok, T.; Patron, Z.; Fiedorowicz, H.

2016-12-01

A compact size microscope based on nitrogen double stream gas puff target soft X-ray source, which emits radiation in water-window spectral range at the wavelength of λ = 2.88 nm is presented. The microscope employs ellipsoidal grazing incidence condenser mirror for sample illumination and silicon nitride Fresnel zone plate objective for object magnification and imaging. The microscope is capable of capturing water-window images of objects with 60 nm spatial resolution and exposure time as low as a few seconds. Details about the microscopy system as well as some examples of different applications from various fields of science, are presented and discussed.

Elucidating the Wavelength Dependence of Phonon Scattering in Nanoparticle-Matrix Composites using Phonon Spectroscopy

DTIC Science & Technology

2016-07-11

composites with x - ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Rutherford backscattering spectroscopy...RBS), particle-induced x - ray emission (PIXE), and energy dispersive x - ray spectroscopy (EDX). This work complements earlier works on CdSe...sample shows only In2Se3 and CdIn2Se4 XRD peaks (Figure 1.4e), it is stoichiometrically   Figure 1.4. X - ray diffraction patterns of (a) γ-In2Se3

Mechanical design of a precision linear flexural stage for 3D x-ray diffraction microscope at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Shu, D.; Liu, W.; Kearney, S.; Anton, J.; Tischler, J. Z.

2015-09-01

The 3-D X-ray diffraction microscope is a new nondestructive tool for the three-dimensional characterization of mesoscopic materials structure. A flexural-pivot-based precision linear stage has been designed to perform a wire scan as a differential aperture for the 3-D diffraction microscope at the Advanced Photon Source, Argonne National Laboratory. The mechanical design and finite element analyses of the flexural stage, as well as its initial mechanical test results with laser interferometer are described in this paper.

Electron microscopy methods in studies of cultural heritage sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vasiliev, A. L., E-mail: a.vasiliev56@gmail.com; Kovalchuk, M. V.; Yatsishina, E. B.

The history of the development and application of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray microanalysis (EDXMA) in studies of cultural heritage sites is considered. In fact, investigations based on these methods began when electron microscopes became a commercial product. Currently, these methods, being developed and improved, help solve many historical enigmas. To date, electron microscopy combined with microanalysis makes it possible to investigate any object, from parchment and wooden articles to pigments, tools, and objects of art. Studies by these methods have revealed that some articles were made by ancient masters using ancient “nanotechnologies”; hence,more » their comprehensive analysis calls for the latest achievements in the corresponding instrumental methods and sample preparation techniques.« less

Mechanical properties of Al-Cu alloy-SiC composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anggara, B. S., E-mail: anggorobs1960@yahoo.com; Handoko, E.; Soegijono, B.

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to getmore » better quality of back to back hardness Vickers of Al-Cu alloys.« less

Electrochemical Study of Cobalt in Urea and Choline Chloride

NASA Astrophysics Data System (ADS)

Li, Min; Shi, Zhongning; Wang, Zhaowen; Reddy, Ramana G.

The nucleation mechanism of Co(II) in urea-choline chloride-CoCl2 melt at 373 K was studied using chronoamperometry. Chronoamperometry experiments confirm that the electrodeposition of cobalt on tungsten electrode is governed by three-dimensional (3D) progressive nucleation and diffusion-controlled growth mechanisms. The average diffusion coefficient of Co(II) in the melt at 373 K is 1.1 × 10-6 cm2 s-1, which is in good agreement with the estimated value obtained from cyclic voltammetry data. Characterization of the Co electrodeposit using scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) techniques indicate that the electrodeposit obtained at -0.75 V and 373 K contain dense and compact surface formed from pure cobalt metal.

Mechanical properties of Al-Cu alloy-SiC composites

NASA Astrophysics Data System (ADS)

Anggara, B. S.; Handoko, E.; Soegijono, B.

2014-09-01

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.

Electron microscopy methods in studies of cultural heritage sites

NASA Astrophysics Data System (ADS)

Vasiliev, A. L.; Kovalchuk, M. V.; Yatsishina, E. B.

2016-11-01

The history of the development and application of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray microanalysis (EDXMA) in studies of cultural heritage sites is considered. In fact, investigations based on these methods began when electron microscopes became a commercial product. Currently, these methods, being developed and improved, help solve many historical enigmas. To date, electron microscopy combined with microanalysis makes it possible to investigate any object, from parchment and wooden articles to pigments, tools, and objects of art. Studies by these methods have revealed that some articles were made by ancient masters using ancient "nanotechnologies"; hence, their comprehensive analysis calls for the latest achievements in the corresponding instrumental methods and sample preparation techniques.

Gas sensing performance of nano zinc oxide sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Shiva, E-mail: shivasharmaau@gmail.com; Chauhan, Pratima, E-mail: mangu167@yahoo.co.in

We report nano Zinc Oxide (ZnO) synthesized by sol-gel method possessing the crystallite size which varies from 25.17 nm to 47.27 nm. The Scanning electron microscope (SEM) image confirms the uniform distribution of nanograins with high porosity. The Energy dispersion X-ray (EDAX) spectrum gives the atomic composition of Zn and O in ZnO powders and confirms the formation of nano ZnO particles. These factors reveals that Nano ZnO based gas sensors are highly sensitive to Ammonia gas (NH{sub 3}) at room temperature, indicating the maximum response 86.8% at 800 ppm with fast response time and recovery time of 36 sec and 23 secmore » respectively.« less

Effect of Y2O3 on polyindole for high frequency capacitor application

NASA Astrophysics Data System (ADS)

Maji, P.; Choudhary, R. B.; Majhi, M.

2017-05-01

Polyindole-Yittrium Oxide (PIn-Y2O3) composite was synthesized in the laboratory through chemical polymerization process. The structural and morphological studies of PIn-Y2O3 composite were investigated using X-ray diffraction (XRD) and scanning electron microscopic (SEM) techniques. These studies showed that PIn-Y2O3 composite was amorphous in nature and formed with spherical granule shape. The dielectric response was measured through LCR meter in the frequency range from 100 Hz to 1 MHz. The dielectric studies revealed that incorporation of Y2O3 into polymeric matrix improved the dielectric behavior of PIn polymer and markedly suitable for its application in high frequency capacitor and many other electronic devices.

Electrochromic NiO thin films prepared by spin coating

NASA Astrophysics Data System (ADS)

Özütok, F.; Demiri, S.; Özbek, E.

2017-02-01

Recently, smart windows are very important because they are often being used in smart buildings and car glasses (windows). At this point, producing effective electrochromic materials is so necessary. In this study, we produced NiO thin films by using spin coating technique on In-doped SnO2 (ITO) substrate. Nickel proportions of these nickel oxide (NiO) films are 3, 5 and 7 %. Nickel acetate tetrahydrate is the initial solution and solvents are ethylene gl ycol and n-hexzane. Structural properties and surface images are investigated by using x-ray diffactometer (XRD) and scanning electron microscope (SEM) device, respectively. In addition, electrochemical behavior is investigated by cyclic voltammetry. A correlation between surface morphology and electrochromic performance was observed as well.

Corrosion inhibition of aminated hydroxyl ethyl cellulose on mild steel in acidic condition.

PubMed

Sangeetha, Y; Meenakshi, S; Sairam Sundaram, C

2016-10-05

Aminated hydroxyethyl cellulose (AHEC) was synthesized, characterized using Fourier Transform Infrared spectroscopy (FTIR) and the corrosion inhibition of AHEC on mild steel in 1M HCl was studied using chemical and electrochemical studies. Results obtained in weight loss method showed that inhibition efficiency increased with increase in concentration of AHEC. The adsorption of the inhibitor on metal surface followed Frumkin isotherm. Polarization studies revealed that the AHEC inhibits through mixed mode. Thermodynamic parameters and activation energy were calculated and discussed. FTIR and X-ray diffraction studies (XRD) confirmed the adsorption of the inhibitor. The surface morphology was studied using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM). Copyright © 2016 Elsevier Ltd. All rights reserved.

Catharanthus roseus: a natural source for the synthesis of silver nanoparticles

PubMed Central

Mukunthan, KS; Elumalai, EK; Patel, Trupti N; Murty, V Ramachandra

2011-01-01

Objective To develop a simple rapid procedure for bioreduction of silver nanoparticles (AgNPs) using aqueous leaves extracts of Catharanthus roseus (C. roseus). Methods Characterization were determined by using UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. Results SEM showed the formation of silver nanoparticles with an average size of 67 nm to 48 nm. X-ray diffraction analysis showed that the particles were crystalline in nature with face centered cubic geometry. Conclusions C. roseus demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0). This study provides evidence for developing large scale commercial production of value-added products for biomedical/nanotechnology-based industries. PMID:23569773

Enhanced magneto-optical and photo-catalytic properties of transition metal cobalt (Co2+ ions) doped spinel MgFe2O4 ferrite nanocomposites

NASA Astrophysics Data System (ADS)

Abraham, A. Godlyn; Manikandan, A.; Manikandan, E.; Vadivel, S.; Jaganathan, S. K.; Baykal, A.; Renganathan, P. Sri

2018-04-01

In this study, spinel magnesium cobalt ferrite (CoxMg1-xFe2O4: x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanocomposites were synthesized successfully by modified sol-gel combustion method. Magnesium nitrate, cobalt nitrate and iron nitrate were used as the source of divalent (Mg2+ and Co2+) and trivalent (Fe3+) cations, respectively and urea were used as the reducing (fuel) agent. The effects of cobalt ions on morphology, structural, optical, magnetic and photo-catalytic properties of spinel CoxMg1-xFe2O4 nanocomposites were investigated. Various characterization methods, including X-ray powder diffraction (XRD), high resolution scanning electron microscope (HR-SEM), transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transforms infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM) and photo-catalytic degradation (PCD) activity were used to study the phase purity, microstructure, particle size, elemental composition, functional group determination, band gap calculation, magnetic properties and degradation efficiency of nanoparticles, respectively. The observed results showed that the final products consists cubic spinel phase with sphere-like nanoparticles morphologies. Furthermore, spinel Co0.6Mg0.4Fe2O4 nanocomposite showed highest PCD efficiency (98.55%) than other composition of ferrite nanoparticles.

Statistical analysis of low-voltage EDS spectrum images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, I.M.

1998-03-01

The benefits of using low ({le}5 kV) operating voltages for energy-dispersive X-ray spectrometry (EDS) of bulk specimens have been explored only during the last few years. This paper couples low-voltage EDS with two other emerging areas of characterization: spectrum imaging of a computer chip manufactured by a major semiconductor company. Data acquisition was performed with a Philips XL30-FEG SEM operated at 4 kV and equipped with an Oxford super-ATW detector and XP3 pulse processor. The specimen was normal to the electron beam and the take-off angle for acquisition was 35{degree}. The microscope was operated with a 150 {micro}m diameter finalmore » aperture at spot size 3, which yielded an X-ray count rate of {approximately}2,000 s{sup {minus}1}. EDS spectrum images were acquired as Adobe Photoshop files with the 4pi plug-in module. (The spectrum images could also be stored as NIH Image files, but the raw data are automatically rescaled as maximum-contrast (0--255) 8-bit TIFF images -- even at 16-bit resolution -- which poses an inconvenience for quantitative analysis.) The 4pi plug-in module is designed for EDS X-ray mapping and allows simultaneous acquisition of maps from 48 elements plus an SEM image. The spectrum image was acquired by re-defining the energy intervals of 48 elements to form a series of contiguous 20 eV windows from 1.25 kV to 2.19 kV. A spectrum image of 450 x 344 pixels was acquired from the specimen with a sampling density of 50 nm/pixel and a dwell time of 0.25 live seconds per pixel, for a total acquisition time of {approximately}14 h. The binary data files were imported into Mathematica for analysis with software developed by the author at Oak Ridge National Laboratory. A 400 x 300 pixel section of the original image was analyzed. MSA required {approximately}185 Mbytes of memory and {approximately}18 h of CPU time on a 300 MHz Power Macintosh 9600.« less

Arsenic detection in water: YPO{sub 4}:Eu{sup 3+} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Debasish; Luwang, Meitram Niraj, E-mail: mn.luwang@ncl.res.in; Academy of Scientific and Innovative Research

This work reports on the novel technique of detection of arsenic in aqueous solution utilising the luminescence properties of lanthanide doped nanomaterials. Eu{sup 3+} (5%) doped YPO{sub 4}nanorodswere utilised for the said experiment. Co-precipitation method was used for the synthesis of the materials and characterised them with different instrumental techniques like X-ray diffraction (XRD), Infra-red (IR), UV-absorption, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence studies. This nanoparticle can adsorb both arsenic and arsenious acids. We studied the effect of arsenic adsorption on the luminescence behaviour of the nanoparticles. Arsenic acid enhanced the luminescencemore » intensity whereas arsenious acid quenched the luminescence. This luminescence enhancement or quenching is related with arsenic concentration. This relation of luminescence property with concentration of arsenic can be used to detect arsenic in industrial waste. - Graphical abstract: Novel technique of detection of Arsenic ion in aqueous solution utilising the luminescence properties of lanthanide doped nanomaterials. Potential application for detection of arsenic in drinking and industrial waste water. - Highlights: • Novel technique of detection of Arsenic in aqueous solution by YPO{sub 4}:Eu{sup 3+} nanomaterials. • The effect of arsenic adsorption on the luminescence behaviour of the nanoparticles was studied. • Arsenic acid enhance whereas arsenious acid quenches the luminescence intensity. • This technique can be used to detect arsenic in industrial waste.« less

Photocatalysis-assisted water filtration: using TiO2-coated vertically aligned multi-walled carbon nanotube array for removal of Escherichia coli O157:H7.

PubMed

Oza, Goldie; Pandey, Sunil; Gupta, Arvind; Shinde, Sachin; Mewada, Ashmi; Jagadale, Pravin; Sharon, Maheshwar; Sharon, Madhuri

2013-10-01

A porous ceramic was coated with vertically aligned multi-walled carbon nanotubes (MWCNTs) by spray pyrolysis. Titanium dioxide (TiO2) nanoparticles were then coated onto this densely aligned MWCNT. The presence of TiO2/MWCNT interfacial arrays was confirmed by X-ray diffraction (XRD), scanning electron microscope-energy dispersive analysis of X-ray (SEM-EDAX) and transmission electron microscope (TEM). This is a novel report in which water loaded with a most dreadful enterohemorrhagic pathogenic strain of Escherichia coli O157:H7 was filtered through TiO2/MWCNT coated porous ceramic filter and then analysed. Bacterial removal performance was found to be significantly lower in control i.e. plain porous ceramic (P<0.05) as compared to TiO2/MWCNT coated ceramic. The photocatalytic killing rate constant for TiO2-ceramic and MWCNT/TiO2-ceramic under fluorescent light was found be 1.45×10(-2) min(-1) and 2.23×10(-2) min(-1) respectively. Further, when I-V characteristics were performed for TiO2/MWCNT composite, it was corroborated that the current under light irradiation is comparatively higher than that in dark, thus proving it to be photocatalytically efficient system. The enhanced photocatalysis may be a contribution of increased surface area and charge transfer rate as a consequence of aligned MWCNT network. © 2013 Elsevier B.V. All rights reserved.

The electrocatalytic reduction of nitrate in water on Pd/Sn-modified activated carbon fiber electrode.

PubMed

Wang, Ying; Qu, Jiuhui; Wu, Rongcheng; Lei, Pengju

2006-03-01

The Pd/Sn-modified activated carbon fiber (ACF) electrodes were successfully prepared by the impregnation of Pd2+ and Sn2+ ions onto ACF, and their electrocatalytic reduction capacity for nitrate ions in water was evaluated in a batch experiment. The electrode was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and temperature programmed reduction (TPR). The capacity for nitrate reduction depending on Sn content on the electrode and the pH of electrolyte was discussed at length. The results showed that at an applied current density of 1.11 mA cm(-2), nitrate ions in water (solution volume: 400 mL) were reduced from 110 to 3.4 mg L(-1) after 240 min with consecutive change of intermediate nitrite. Ammonium ions and nitrogen were formed as the main final products. The amount of other possible gaseous products (including NO and N2O) was trace. With the increase of Sn content on the Pd/Sn-modified ACF electrode, the activity for nitrate reduction went up to reach a maximum (at Pd/Sn = 4) and then decreased, while the selectivity to N2 was depressed. Higher pH value of electrolyte exhibited more suppression effect on the reduction of nitrite than that of nitrate. However, no significant influence on the final ammonia formation was observed. Additionally, Cu ion in water was found to cover the active sites of the electrode to make the electrode deactivated.

Production and Characterization of Nanosilica from Bagasse Through Biosynthesis Using Lactobacilus bulgaricus.

PubMed

Rahmawati, Nanda Yuli; Harisna, Azza Hanief; Khoirunnisa, Wulida; Yasvinawati, Niarisandi; Sumitro, Sutiman Bambang

2016-06-01

Bagasse has a potential as natural resource of nanosilica. Nanosilica biosynthetic production method is better than chemical or physical methods. The aim of this study is to determine the potential of Lactobacillus bulgaricus in nanosilica synthesis, the effect of the long incubation, and the effect of freeze drying to the nanosilica quality. The method consists of two steps. The first is performing biosynthesize using bagasse and Lactobacillus bulgaricus in dark place with temperature of 37 degress C for the period of 24 hours, 48 hours, and 72 hours. The second is analyzing particles and chemical of nanosilica characterization using Fourier Transformer Infrared Spectroscopy (FTIR), Particle Size Analyzer (PSA), X-ray Diffraction (XRD), some microscopes namely stereo, fluorescence, polarizing, Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX). The results show that nanosilica has spherical shaped, amorphous, and able to fluoresce when exposed by UV. The average size of particles are 104.6 nm in the 24 hours length incubated, 67.3 nm in the 48 hours length incubation, and 30.5 nm in the 72 hours length incubation. Samples using freeze drying have more complex and smaller structure than samples using air drying. The lengths of incubation influence the size and shape of nanosilica. Samples using freeze drying enable change the soil structure, and has beneficiary effect to improve soil fertility, as nanofertilizer. Whereas, the samples using air drying may use for glass or biofilm materials.

Microscopic composition measurements of organic individual particles collected in the Southern Great Plains

NASA Astrophysics Data System (ADS)

Bonanno, D.; China, S.; Fraund, M. W.; Pham, D.; Kulkarni, G.; Laskin, A.; Gilles, M. K.; Moffet, R.

2016-12-01

The Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) Campaign was carried out to gain a better understanding of the lifecycle of shallow clouds. The HISCALE experiment was designed to contrast two seasons, wet and dry, and determine their effect on atmospheric cloud and aerosol processes. The spring component to HISCALE was selected to characterize mixing state for particles collected onto substrates. Sampling was performed before and after rain events to obtain airborne soil organic particles (ASOP), which are ejected after rain events. The unique composition of the ASOP may affect optical properties and/or hygroscopic properties. The collection of particles took place at the Atmospheric Radiation Measurement Southern Great Plains (ARM SGP) field site. The Scanning Transmission X-Ray Microscope (STXM) was used to image the samples collected during the first HI-SCALE Campaign to determine the carbonaceous mixing state. Scanning Electron Microscopy Energy-dispersive X-ray (SEM/EDX) analysis is more sensitive to the inorganic makeup of particles, while STXM renders a more comprehensive analysis of the organics. Measurements such as nephelometry, Particle Soot Absorption Photometry (PSAP), and Aerosol Mass Spectrometry (AMS) from the ARM archive will be correlated with microscopy measurements. The primary focus is the relation between composition and morphology of ASOP with hygroscopicity and optical properties. Further investigation of these organic particles will be performed to provide a mixing state parameterization and aid in the advancement of current climate models.

TiO2 nanoparticles versus TiO2-SiO2 nanocomposites: A comparative study of photo catalysis on acid red 88

NASA Astrophysics Data System (ADS)

Balachandran, K.; Venckatesh, Rajendran; Sivaraj, Rajeshwari; Rajiv, P.

2014-07-01

A novel, simple, less time-consuming and cost-effective wet chemical technique was used to synthesis TiO2 nanoparticles and TiO2-SiO2 nanocomposites using Titanium tetra isopropoxide (TTIP) as a precursor relatively at low temperature in acidic pH. Titania sol was prepared by hydrolysis of TTIP and was mixed with silicic acid and tetrahydrofuran mixture. The reaction was carried out under vigorous stirring for 6 h and dried at room temperature. The resulting powders were characterized by UV-Visible spectroscopy, Fourier transform infrared (FT-IR), X-ray diffraction, scanning electron microscope (SEM) and transmission electron microscope (TEM). The grain size of the particles was calculated by X-ray diffraction, surface morphology and chemical composition was determined from scanning electron microscopy-energy dispersive spectroscopy, metal oxide stretching was confirmed from FT-IR spectroscopy, band gap was calculated using UV-Visible spectroscopy. Surface area of the composite as calculated by BET analyzer and it was found to be 65 and 75 m2/g for TiO2 and TiO2-SiO2 respectively. The photocatalytic experiments were performed with aqueous solution of acid red 88 with TiO2 and TiO2-SiO2 batch studies for 4 h irradiation, direct photolysis of TiO2 and TiO2-SiO2 contributed 94.2% and 96.5% decomposition in solar radiation for the optimized concentration of acid red 88.

1.55 µm emission from a single III-nitride top-down and site-controlled nanowire quantum disk

NASA Astrophysics Data System (ADS)

Chen, Qiming; Yan, Changling; Qu, Yi

2017-07-01

InN/InGaN single quantum well (SQW) was fabricated on 100 nm GaN buffer layer which was deposited on GaN template by plasma assisted molecular beam epitaxy (PA-MBE). The In composition and the surface morphology were measured by x-ray diffusion (XRD) and atom force microscope (AFM), respectively. Afterwards, the sample was fabricated into site-controlled nanowires arrays by hot-embossing nano-imprint lithography (HE-NIL) and ultraviolet nanoimprint lithography (UV-NIL). The nanowires were uniform along the c-axis and aligned periodically as presented by scanning electron microscope (SEM). The single nanowire showed disk-in-a-wire structure by high angle annular dark field (HAADF) and an In-rich or Ga deficient region was observed by energy dispersive x-ray spectrum (EDXS). The optical properties of the SQW film and single nanowire were measured using micro photoluminescence (µ-PL) spectroscopy. The stimulating light wavelength was 632.8 nm which was emitted from a He-Ne laser and the detector was a liquid nitrogen cooled InGaAs detector. A blue peak shift from the film material to the nanowire was observed. This was due to the quantum confinement Stark Effect. More importantly, the 1.55 µm emission was given from the single disk-in-a-wire structure at room temperature. We believe the arrays of such nanowires may be useful for quantum communication in the future.

Microgravity

NASA Image and Video Library

2004-04-15

To the crystallographer, this may not be a diamond but it is just as priceless. A Lysozyme crystal grown in orbit looks great under a microscope, but the real test is X-ray crystallography. The colors are caused by polarizing filters. Proteins can form crystals generated by rows and columns of molecules that form up like soldiers on a parade ground. Shining X-rays through a crystal will produce a pattern of dots that can be decoded to reveal the arrangement of the atoms in the molecules making up the crystal. Like the troops in formation, uniformity and order are everything in X-ray crystallography. X-rays have much shorter wavelengths than visible light, so the best looking crystals under the microscope won't necessarily pass muster under the X-rays. In order to have crystals to use for X-ray diffraction studies, crystals need to be fairly large and well ordered. Scientists also need lots of crystals since exposure to air, the process of X-raying them, and other factors destroy them. Growing protein crystals in space has yielded striking results. Lysozyme's structure is well known and it has become a standard in many crystallization studies on Earth and in space.

Lysozyme Crystal

NASA Technical Reports Server (NTRS)

2004-01-01

To the crystallographer, this may not be a diamond but it is just as priceless. A Lysozyme crystal grown in orbit looks great under a microscope, but the real test is X-ray crystallography. The colors are caused by polarizing filters. Proteins can form crystals generated by rows and columns of molecules that form up like soldiers on a parade ground. Shining X-rays through a crystal will produce a pattern of dots that can be decoded to reveal the arrangement of the atoms in the molecules making up the crystal. Like the troops in formation, uniformity and order are everything in X-ray crystallography. X-rays have much shorter wavelengths than visible light, so the best looking crystals under the microscope won't necessarily pass muster under the X-rays. In order to have crystals to use for X-ray diffraction studies, crystals need to be fairly large and well ordered. Scientists also need lots of crystals since exposure to air, the process of X-raying them, and other factors destroy them. Growing protein crystals in space has yielded striking results. Lysozyme's structure is well known and it has become a standard in many crystallization studies on Earth and in space.

Symposium LL: Nanowires--Synthesis Properties Assembly and Application

DTIC Science & Technology

2010-09-10

dedicated hard x - ray microscopy beamline is operated in partnership with the Advanced Photon Source to provide fluorescence, diffraction, and...characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X - ray diffraction (XRD) measurements, proving it to be...Investigation of Preferred Growth Direction of GaN Nanorods by Synchrotron X - ray Reciprocal Space Mapping. Yuri Sohn1, Sanghwa Lee1, Chinkyo Kim1 and Dong

SEM Microanalysis of Particles: Concerns and Suggestions

NASA Astrophysics Data System (ADS)

Fournelle, J.

2008-12-01

The scanning electron microscope (SEM) is well suited to examine and characterize small (i.e. <10 micron) particles. Particles can be imaged and sizes and shapes determined. With energy dispersive x-ray spectrometers (EDS), chemical compositions can be determined quickly. Despite the ease in acquiring x-ray spectra and chemical compositions, there are potentially major sources of error to be recognized. Problems with EDS analyses of small particles: Qualitive estimates of composition (e.g. stating that Si>Al>Ca>Fe plus O) are easy. However, to be able to have confidence that a chemical composition is accurate, several issues should be examined. (1) Particle Mass Effect: Is the accelerating voltage appropriate for the specimen size? Are all the incident electrons remaining inside the particle, and not traveling out of the sample side or bottom? (2) Particle Absorption Effect: What is the geometric relationship of the beam impact point to the x-ray detector? The x-ray intensity will vary by significant amounts for the same material if the grains are irregular and the path out of the sample in the direction of the detector is longer or shorter. (3) Particle Fluorescence Effect: This is generally a smaller error, but should be considered: for small particles, using large standards, there will be a few % less x-rays generated in a small particle relative to one of the same composition and 50-100 times larger. Also, if the sample sits on a grid of a particular composition (e.g. Si wafer) potentially several % of Si could appear in the analysis. (4) In a increasing number of laboratories, with environmental or variable pressure SEMs, the Gas Skirt Effect is operating against you: here the incident electron beam scatters in the gas in the chamber, with less electrons impacting the target spot and some others hitting grains 100s of microns away, producing spectra that could be faulty. (5) Inclusion of measured oxygen: if the measured oxygen x-ray counts are utilized, significant errors can be introduced by differential absorption of this low energy x-ray. (6) Standardless Analysis: This typical method of doing EDS analysis has a major pitfall: the printed analysis is normalized to 100 wt%, thereby eliminating an important clue to analytical error. Suggestions: (1) Use lower voltage, e.g. 10 kV, reducing effects 1,2,3 above. (2) Use standards--traditional flat polished ones--and don't initially normalize totals. Discrepancies can be observed and addressed, not ignored. (3) Alway include oxygen by stoichometry, not measured. (4) Experimental simulation. Using material of constant composition (e.g. NIST glass K-411, or other homogeneous multi-element material with the elements of interest), grind into fragments of similar size to your unknowns, and see what is the analytical error for measurements of these known particles. Analyses of your unknown material will be no better, and probably worse than that, particularly if the grains are smaller. The results of this experiment should be reported whenever discussing measurements on the unknown materials. (5) Monte Carlo simulation. Programs such PENEPMA allows creation of complex geometry samples (and samples on substrates) and resulting EDS spectra can be generated. This allows estimation of errors for representative cases. It is slow, however; other simulations such as DTSA-II promise faster simulations with some limitations. (6) EBSD: this is a perfectly suited for some problems with SEM identification of small particles, e.g. distinguishing magnetite (Fe3O4) from hematite (Fe2O3), which is virtually impossible to do by EDS. With the appropriate hardware and software, electron diffraction patterns on particles can be gathered and the crystal type determined.

King's College London/SERC Daresbury Scanning X-ray Microscope

NASA Astrophysics Data System (ADS)

Burge, R. E.; Browne, M. T.; Buckley, C. J.; Cave, R.; Charalambous, P.; Duke, P. J.; Freake, A. J.; Hare, A.; Hills, C. P. B.; Kenney, J. M.; Kuriyama, T.; Lidiard, D.; MacDowell, A.; Michette, A. G.; Morrison, G. R.; Ogawa, K.; Rogoyski, A. M.

1986-01-01

The present status of the soft X-ray microscope is described and a short description is given, with likely development paths for the future, of the Daresbury synchrotron source, the monochromator, the high-resolution zone-plates, the scanning specimen stage, image recording and methods of image enhancement. It is considered that the instrumental developments needed for images at 10 nm resolution will take a further two or three years.

Assets and pitfalls of chemical and microscopic analyses on gunshot residues in skeletonized bodies: a report of five cases.

PubMed

Amadasi, Alberto; Gibelli, Daniele; Mazzarelli, Debora; Porta, Davide; Gaudio, Daniel; Salsarola, Dominic; Brandone, Alberto; Rizzi, Agostino; Cattaneo, Cristina

2015-07-01

In case of gunshot wounds, forensic anthropologists and pathologists have many tools at hand, and the assistance that chemical and microscopic investigations can provide in such scenarios is often valuable and crucial. However, the results of such analyses in the search of gunshot residues (GSR) ought not to be acritically considered. We report five cases where chemical (sodium rhodizonate) and microscopic (scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX)) analyses were performed for the search of GSR. Four cases concerned the forensic field and analyses on buried, charred, or submerged remains, whereas one case concerned the historical remains of a soldier of the First World War. In every case, the search for GSR with these techniques showed their persistence even after long periods and preservation in peculiar environments. However, chemical analyses provided their contribution, but in two cases, anthropological analyses provided crucial and solving results. The five cases show the indisputable usefulness of chemical and microscopic analyses in the search of GSR in gunshot wounds and especially how such residues may survive in time and in adverse environmental conditions. However, experts should always be dubious about some pitfalls (such as contamination) one can frequently find in these scenarios.

A full-field transmission x-ray microscope for time-resolved imaging of magnetic nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ewald, J.; Nisius, T.; Abbati, G.

Sub-nanosecond magnetization dynamics of small permalloy (Ni{sub 80}Fe{sub 20}) elements has been investigated with a new full-field transmission microscope at the soft X-ray beamline P04 of the high brilliance synchrotron radiation source PETRA III. The soft X-ray microscope generates a flat-top illumination field of 20 μm diameter using a grating condenser. A tilted nanostructured magnetic sample can be excited by a picosecond electric current pulse via a coplanar waveguide. The transmitted light of the sample plane is directly imaged by a micro zone plate with < 65 nm resolution onto a 2D gateable X-ray detector to select one particular bunch in themore » storage ring that probes the time evolution of the dynamic information successively via XMCD spectromicroscopy in a pump-probe scheme. In the experiments it was possible to generate a homogeneously magnetized state in patterned magnetic layers by a strong magnetic Oersted field pulse of 200 ps duration and directly observe the recovery to the initial flux-closure vortex patterns.« less

The approach to reflection x-ray microscopy below the critical angles

NASA Astrophysics Data System (ADS)

Artyukov, Igor A.; Busarov, Alexander; Popov, Nikolay L.; Vinogradov, Alexander V.

2017-05-01

There is a quest for new knowledge and methods to study various materials and processes on surfaces and interfaces at the nanoscale. It concerns ablation, phase transitions, physical and chemical transformations, dissolution, selforganization etc. Obviously, to achieve an appropriate resolution it is necessary to use a corresponding wavelength . Higher resolution can be obtained with shorter wavelengths. On the other hand, in surface modification, ablation, study of buried interfaces etc. the penetration length of radiation into the materials, which depends on the wavelength and angle of incidence, plays important role... Considering these factors the experimental studies in nano-physics and nanotechnology are usually carried out using X-ray radiation with a photon energy of 0.1-10 keV. As far as surfaces and films are investigated, it is reasonable to use an X-ray microscope operating in the reflection mode. However, in this spectral range a substantial portion of the radiation is reflected only at small grazing angles (e.g. <= 10°). Thus, the idea of grazing incidence reflection-mode X-ray microscope has been developed. In this paper, we consider one of possible schemes of such an X-ray microscope. Our analysis and simulation is based on the extension of the Fresnel propagation theory to tilted object problems.

X-ray mosaic nanotomography of large microorganisms.

PubMed

Mokso, R; Quaroni, L; Marone, F; Irvine, S; Vila-Comamala, J; Blanke, A; Stampanoni, M

2012-02-01

Full-field X-ray microscopy is a valuable tool for 3D observation of biological systems. In the soft X-ray domain organelles can be visualized in individual cells while hard X-ray microscopes excel in imaging of larger complex biological tissue. The field of view of these instruments is typically 10(3) times the spatial resolution. We exploit the assets of the hard X-ray sub-micrometer imaging and extend the standard approach by widening the effective field of view to match the size of the sample. We show that global tomography of biological systems exceeding several times the field of view is feasible also at the nanoscale with moderate radiation dose. We address the performance issues and limitations of the TOMCAT full-field microscope and more generally for Zernike phase contrast imaging. Two biologically relevant systems were investigated. The first being the largest known bacteria (Thiomargarita namibiensis), the second is a small myriapod species (Pauropoda sp.). Both examples illustrate the capacity of the unique, structured condenser based broad-band full-field microscope to access the 3D structural details of biological systems at the nanoscale while avoiding complicated sample preparation, or even keeping the sample environment close to the natural state. Copyright © 2012 Elsevier Inc. All rights reserved.

The macroscopic, microscopic and spectrometric effects of various chemotherapeutic agents on the plasma-sprayed hydroxyapatite-coated implant surface.

PubMed

Zablotsky, M; Meffert, R; Mills, O; Burgess, A; Lancaster, D

1992-12-01

The purpose of this research was to determine the nature of the residual hydroxyapatite (HA)-coated implant surface after treatment with various chemotherapeutic modalities, including: citric acid, chlorhexidine gluconate, hydrogen peroxide, tetracycline HCl, stannous fluoride, polymyxin B and a prototype plastic Cavitron tip. Implant surfaces were evaluated macroscopically, microscopically (scanning electron microscopy (SEM)) and spectrometrically (energy-dispersive spectrometry and X-ray diffraction). HA-substrate bond strength and dissolution testing was also performed for surfaces treated with a supersaturated citric acid solution. All treatments left either microscopic residues or a loss of surface roughness when viewed on SEM. A 30- to 60-s application of citric acid left a significantly greater coating thickness than all other treatments, whereas a 3-min application of citric acid removed significantly more HA than untreated controls. Significant changes in Ca/P ratios were seen with most treatments. The clinical significance of this phenomenon is not known. No treatments altered the crystallinity of the residual HA coating. A 1-min application of citric acid did not significantly alter the tensile bond strength of the coating to the substrate. The clinical significance of these findings is not known at present. However, when taken with results from previous studies, it appears that in treating the infected HA-coated implant surface, a 30- to 60-s application of citric acid (pH 1) may be beneficial in detoxifying the HA coating prior to regenerative procedures. Further in vitro and in vivo studies are necessary to evaluate the biological response to citric acid when used to detoxify the infected implant surface.

Broadband X-ray edge-enhancement imaging of a boron fibre on lithium fluoride thin film detector

NASA Astrophysics Data System (ADS)

Nichelatti, E.; Bonfigli, F.; Vincenti, M. A.; Cecilia, A.; Vagovič, P.; Baumbach, T.; Montereali, R. M.

2016-10-01

The white beam (∼6-80 keV) available at the TopoTomo X-ray beamline of the ANKA synchrotron facility (KIT, Karlsruhe, Germany) was used to perform edge-enhancement imaging tests on lithium fluoride radiation detectors. The diffracted X-ray image of a microscopic boron fibre, consisting of tungsten wire wrapped by boron cladding, was projected onto lithium fluoride thin films placed at several distances, from contact to 1 m . X-ray photons cause the local formation of primary and aggregate colour centres in lithium fluoride; these latter, once illuminated under blue light, luminesce forming visible-light patterns-acquired by a confocal laser scanning microscope-that reproduce the intensity of the X-ray diffracted images. The tests demonstrated the excellent performances of lithium fluoride films as radiation detectors at the investigated photon energies. The experimental results are here discussed and compared with those calculated with a model that takes into account all the processes that concern image formation, storing and readout.

Synthesis, structure and electromagnetic properties of Mn-Zn ferrite by sol-gel combustion technique

NASA Astrophysics Data System (ADS)

Wang, Wenjie; Zang, Chongguang; Jiao, Qingjie

2014-01-01

The electromagnetic absorbing behaviors of a thin coating fabricated by mixing Mn-Zn ferrite with epoxy resin (EP) were studied. The spinel ferrites Mn1-xZnxFe2O4 (x=0.2, 0.5 and 0.8) were synthesized with citrate acid as complex agent by sol-gel combustion method. The microstructure and surface morphology of Mn-Zn ferrite powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The complex permittivity and complex permeability of the fabricated ferrite/EP composites were investigated in terms of their contributions to the absorbing properties in the low frequency (10 MHz to 1 GHz). The microwave absorption of the prepared ferrite/EP composites could be tailored by matching the dielectric loss and magnetic loss and by controlling the doped metal ratio. The composites with the ferrite composition x=0.2 are found to show higher reflection loss compared with the composites with other compositions. It is proposed that the prepared composites can potentially be applied in electromagnetic microwave absorbing field.

The qualitative f-ratio method applied to electron channelling-induced x-ray imaging with an annular silicon drift detector in a scanning electron microscope in the transmission mode.

PubMed

Brodusch, Nicolas; Gauvin, Raynald

2017-09-01

Electron channelling is known to affect the x-ray production when an accelerated electron beam is applied to a crystalline material and is highly dependent on the local crystal orientation. This effect, unless very long counting time are used, is barely noticeable on x-ray energy spectra recorded with conventional silicon drift detectors (SDD) located at a small elevation angle. However, the very high count rates provided by the new commercially available annular SDDs permit now to observe this effect routinely and may, in some circumstances, hide the true elemental x-ray variations due to the local true specimen composition. To circumvent this issue, the recently developed f-ratio method was applied to display qualitatively the true net intensity x-ray variations in a thin specimen of a Ti-6Al-4V alloy in a scanning electron microscope in transmission mode. The diffraction contrast observed in the x-ray images was successfully cancelled through the use of f-ratios and the true composition variations at the grain boundaries could be observed in relation to the dislocation alignment prior to the β-phase nucleation. The qualitative effectiveness in removing channelling effects demonstrated in this work makes the f-ratio, in its quantitative form, a possible alternative to the ZAF method in channelling conditions. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Relative merits and limiting factors for x-ray and electron microscopy of thick, hydrated organic materials.

PubMed

Du, Ming; Jacobsen, Chris

2018-01-01

Electron and x-ray microscopes allow one to image the entire, unlabeled structure of hydrated materials at a resolution well beyond what visible light microscopes can achieve. However, both approaches involve ionizing radiation, so that radiation damage must be considered as one of the limits to imaging. Drawing upon earlier work, we describe here a unified approach to estimating the image contrast (and thus the required exposure and corresponding radiation dose) in both x-ray and electron microscopy. This approach accounts for factors such as plural and inelastic scattering, and (in electron microscopy) the use of energy filters to obtain so-called "zero loss" images. As expected, it shows that electron microscopy offers lower dose for specimens thinner than about 1 µm (such as for studies of macromolecules, viruses, bacteria and archaebacteria, and thin sectioned material), while x-ray microscopy offers superior characteristics for imaging thicker specimen such as whole eukaryotic cells, thick-sectioned tissues, and organs. The required radiation dose scales strongly as a function of the desired spatial resolution, allowing one to understand the limits of live and frozen hydrated specimen imaging. Finally, we consider the factors limiting x-ray microscopy of thicker materials, suggesting that specimens as thick as a whole mouse brain can be imaged with x-ray microscopes without significant image degradation should appropriate image reconstruction methods be identified. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrastructural analysis of dental ceramic surface processed by a 1070 nm fiber laser

NASA Astrophysics Data System (ADS)

Fornaini, C.; Merigo, E.; Poli, F.; Rocca, J.-P.; Selleri, S.; Cucinotta, A.

2018-04-01

Background: Lithium di-silicate dental ceramic bonding, realized by using different resins, is strictly dependent on micro-mechanical retention and chemical adhesion. The aim of this in vitro study was to investigate the capability of a 1070 nm fibre laser for their surface treatment. Methods: Samples were irradiated by a pulsed fibre laser at 1070 nm with different parameters (peak power of 5, 7.5, and 10 kW, repetition rate (RR) 20 kHz, speed of 10 and 50 mm/sec, and total energy density from 1.3 to 27 kW/cm2) Subsequently, the surface modifications were analysed by optical microscope, scanning electron microscope (SEM) and energy dispersive X-ray Spectroscopy (EDS). Results: With a peak power of 5 kW, RR of 20 kHz, and speed of 50 mm/sec, the microscopic observation of the irradiated surface showed increased roughness with small areas of melting and carbonization. EDS analysis revealed that, with these parameters, there are no evident differences between laser-processed samples and controls. Conclusions: A 1070 nm fibre laser can be considered as a good device to increase the adhesion of lithium di-silicate ceramics when optimum parameters are considered.

Direct observation of X-ray induced atomic motion using scanning tunneling microscope combined with synchrotron radiation.

PubMed

Saito, Akira; Tanaka, Takehiro; Takagi, Yasumasa; Hosokawa, Hiromasa; Notsu, Hiroshi; Ohzeki, Gozo; Tanaka, Yoshihito; Kohmura, Yoshiki; Akai-Kasaya, Megumi; Ishikawa, Tetsuya; Kuwahara, Yuji; Kikuta, Seishi; Aono, Masakazu

2011-04-01

X-ray induced atomic motion on a Ge(111)-c(2 x 8) clean surface at room temperature was directly observed with atomic resolution using a synchrotron radiation (SR)-based scanning tunneling microscope (STM) system under ultra high vacuum condition. The atomic motion was visualized as a tracking image by developing a method to merge the STM images before and after X-ray irradiation. Using the tracking image, the atomic mobility was found to be strongly affected by defects on the surface, but was not dependent on the incident X-ray energy, although it was clearly dependent on the photon density. The atomic motion can be attributed to surface diffusion, which might not be due to core-excitation accompanied with electronic transition, but a thermal effect by X-ray irradiation. The crystal surface structure was possible to break even at a lower photon density than the conventionally known barrier. These results can alert X-ray studies in the near future about sample damage during measurements, while suggesting the possibility of new applications. Also the obtained results show a new availability of the in-situ SR-STM system.

Field modeling and ray-tracing of a miniature scanning electron microscope beam column.

PubMed

Loyd, Jody S; Gregory, Don A; Gaskin, Jessica A

2017-08-01

A miniature scanning electron microscope (SEM) focusing column design is introduced and its potential performance assessed through an estimation of parameters that affect the probe radius, to include source size, spherical and chromatic aberration, diffraction and space charge broadening. The focusing column, a critical component of any SEM capable of operating on the lunar surface, was developed by the NASA Marshall Space Flight Center and Advanced Research Systems. The ray-trace analysis presented uses a model of the electrostatic field (within the focusing column) that is first calculated using the boundary element method (BEM). This method provides flexibility in modeling the complex electrode shapes of practical electron lens systems. A Fourier series solution of the lens field is then derived within a cylindrical domain whose boundary potential is provided by the BEM. Used in this way, the Fourier series solution is an accuracy enhancement to the BEM solution, allowing sufficient precision to assess geometric aberrations through direct ray-tracing. Two modes of operation with distinct lens field solutions are described. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Two-year magnetic monitoring in conjunction with geochemical and electron microscopic data of roadside dust in Seoul, Korea

NASA Astrophysics Data System (ADS)

Kim, Wonnyon; Doh, Seong-Jae; Park, Yong-Hee; Yun, Seong-Taek

Mineral magnetic properties of roadside dusts in Seoul, Korea, were measured and compared with the results of geochemical analyses in order to investigate the spatio-temporal patterns of urban pollution. Scanning electron microscope (SEM) observations and energy dispersive X-ray spectroscopy (EDS) analyses were carried out to verify the magnetic materials and their potential sources. A total of 1956 dust samples were collected monthly at eight sites, from June 1998 to June 2000. Thermomagnetic data and SEM observations for magnetic extracts indicated that the major magnetic phase was magnetite-like material. In particular, the highest and the lowest magnetic concentrations were observed in industrial areas and a park area, respectively, whereas, heavy traffic areas showed low to intermediate concentration. A linear correlation between enrichment indexes of magnetic susceptibility and heavy metals suggests that magnetic susceptibility can be used as a proxy for heavy metal pollution. The magnetic concentrations and magnetic particle sizes showed systematic seasonal fluctuations (high and large in winter versus low and small in summer) due to the seasonal influx variations of anthropogenic magnetic materials. On the basis of the morphology and elemental composition, the magnetic materials were grouped into three types: magnetic spherules possibly emitted from factories and domestic heating systems, aggregates derived from vehicle emission or motor vehicle brake system, and angular magnetic particles of natural origin.

Fabrication of Mesoporous Silica/Alumina Hybrid Membrane Film Nanocomposites using Template Sol-Gel Synthesis of Amphiphilic Triphenylene

NASA Astrophysics Data System (ADS)

Lintang, H. O.; Jalani, M. A.; Yuliati, L.; Salleh, M. M.

2017-05-01

Herein we reported that by introducing a one-dimensional (1D) substrate with a porous structure such as anodic aluminum oxide (AAO) membrane, mesoporous silica/alumina hybrid nanocomposites were successfully fabricated by using amphiphilic triphenylene (TPC10TEG) as a template in sol-gel synthesis (TPC10TEG/silicahex). For the optical study of the nanocomposites, TPC10TEG/silicahex showed absorption peak at 264 nm due to the ordered and long-range π-π stacking of the disc-like aromatic triphenylene core. Moreover, the hexagonal arrangement of TPC10TEG/silicahex was proven based on their diffraction peaks of d 100 and d 200 at 2θ = 2.52° and 5.04° and images of transmission electron microscopy (TEM), respectively. For fabrication of mesoporous silica/alumina hybrid membrane, TPC10TEG/silicahex was drop-casted onto AAO membrane for penetration into the porous structure via gravity. X-ray diffraction (XRD) analysis on the resulted hybrid nanocomposites showed that the diffraction peaks of d 100 and d 200 of TPC10TEG/silicahex were still preserved, indicating that the hexagonal arrangements of mesoporous silica were maintained even on AAO substrate. The morphology study on the hybrid nanocomposites using TEM, scanning electron microscope (SEM) and field emission scanning electron microscope (FE-SEM) showed the successful filling of most AAO channels with the TPC10TEG/silicahex nanocomposites.

Confirmatory analysis of field-presumptive GSR test sample using SEM/EDS

NASA Astrophysics Data System (ADS)

Toal, Sarah J.; Niemeyer, Wayne D.; Conte, Sean; Montgomery, Daniel D.; Erikson, Gregory S.

2014-09-01

RedXDefense has developed an automated red-light/green-light field presumptive lead test using a sampling pad which can be subsequently processed in a Scanning Electron Microscope for GSR confirmation. The XCAT's sampling card is used to acquire a sample from a suspect's hands on the scene and give investigators an immediate presumptive as to the presence of lead possibly from primer residue. Positive results can be obtained after firing as little as one shot. The same sampling card can then be sent to a crime lab and processed on the SEM for GSR following ASTM E-1588-10 Standard Guide for Gunshot Residue Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry, in the same manner as the existing tape lifts currently used in the field. Detection of GSR-characteristic particles (fused lead, barium, and antimony) as small as 0.8 microns (0.5 micron resolution) has been achieved using a JEOL JSM-6480LV SEM equipped with an Oxford Instruments INCA EDS system with a 50mm2 SDD detector, 350X magnification, in low-vacuum mode and in high vacuum mode after coating with carbon in a sputter coater. GSR particles remain stable on the sampling pad for a minimum of two months after chemical exposure (long term stability tests are in progress). The presumptive result provided by the XCAT yields immediate actionable intelligence to law enforcement to facilitate their investigation, without compromising the confirmatory test necessary to further support the investigation and legal case.

Binary pseudo-random patterned structures for modulation transfer function calibration and resolution characterization of a full-field transmission soft x-ray microscope

DOE PAGES

Yashchuk, V. V.; Fischer, P. J.; Chan, E. R.; ...

2015-12-09

We present a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) one-dimensional sequences and two-dimensional arrays as an effective method for spectral characterization in the spatial frequency domain of a broad variety of metrology instrumentation, including interferometric microscopes, scatterometers, phase shifting Fizeau interferometers, scanning and transmission electron microscopes, and at this time, x-ray microscopes. The inherent power spectral density of BPR gratings and arrays, which has a deterministic white-noise-like character, allows a direct determination of the MTF with a uniform sensitivity over the entire spatial frequency range and field of view of an instrument. We demonstrate themore » MTF calibration and resolution characterization over the full field of a transmission soft x-ray microscope using a BPR multilayer (ML) test sample with 2.8 nm fundamental layer thickness. We show that beyond providing a direct measurement of the microscope's MTF, tests with the BPRML sample can be used to fine tune the instrument's focal distance. Finally, our results confirm the universality of the method that makes it applicable to a large variety of metrology instrumentation with spatial wavelength bandwidths from a few nanometers to hundreds of millimeters.« less

Advantages of intermediate X-ray energies in Zernike phase contrast X-ray microscopy.

PubMed

Wang, Zhili; Gao, Kun; Chen, Jian; Hong, Youli; Ge, Xin; Wang, Dajiang; Pan, Zhiyun; Zhu, Peiping; Yun, Wenbing; Jacobsen, Chris; Wu, Ziyu

2013-01-01

Understanding the hierarchical organizations of molecules and organelles within the interior of large eukaryotic cells is a challenge of fundamental interest in cell biology. Light microscopy is a powerful tool for observations of the dynamics of live cells, its resolution attainable is limited and insufficient. While electron microscopy can produce images with astonishing resolution and clarity of ultra-thin (<1 μm thick) sections of biological specimens, many questions involve the three-dimensional organization of a cell or the interconnectivity of cells. X-ray microscopy offers superior imaging resolution compared to light microscopy, and unique capability of nondestructive three-dimensional imaging of hydrated unstained biological cells, complementary to existing light and electron microscopy. Until now, X-ray microscopes operating in the "water window" energy range between carbon and oxygen k-shell absorption edges have produced outstanding 3D images of cryo-preserved cells. The relatively low X-ray energy (<540 eV) of the water window imposes two important limitations: limited penetration (<10 μm) not suitable for imaging larger cells or tissues, and small depth of focus (DoF) for high resolution 3D imaging (e.g., ~1 μm DoF for 20 nm resolution). An X-ray microscope operating at intermediate energy around 2.5 keV using Zernike phase contrast can overcome the above limitations and reduces radiation dose to the specimen. Using a hydrated model cell with an average chemical composition reported in literature, we calculated the image contrast and the radiation dose for absorption and Zernike phase contrast, respectively. The results show that an X-ray microscope operating at ~2.5 keV using Zernike phase contrast offers substantial advantages in terms of specimen size, radiation dose and depth-of-focus. Copyright © 2012 Elsevier Inc. All rights reserved.

Transmission X-ray microscopy for full-field nano-imaging of biomaterials

PubMed Central

ANDREWS, JOY C; MEIRER, FLORIAN; LIU, YIJIN; MESTER, ZOLTAN; PIANETTA, PIERO

2010-01-01

Imaging of cellular structure and extended tissue in biological materials requires nanometer resolution and good sample penetration, which can be provided by current full-field transmission X-ray microscopic techniques in the soft and hard X-ray regions. The various capabilities of full-field transmission X-ray microscopy (TXM) include 3D tomography, Zernike phase contrast, quantification of absorption, and chemical identification via X-ray fluorescence and X-ray absorption near edge structure (XANES) imaging. These techniques are discussed and compared in light of results from imaging of biological materials including microorganisms, bone and mineralized tissue and plants, with a focus on hard X-ray TXM at ≤ 40 nm resolution. PMID:20734414

Probing buried layers by photoelectron spectromicroscopy with hard x-ray excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiemann, C.; Patt, M.; Cramm, S.

We report about a proof-of-principle experiment which explores the perspectives of performing hard x-ray photoemission spectromicroscopy with high lateral resolution. Our results obtained with an energy-filtered photoemission microscope at the PETRA III storage ring facility using hard x-ray excitation up to 6.5 keV photon energy demonstrate that it is possible to obtain selected-area x-ray photoemission spectra from regions less than 500 nm in diameter.

Scanning electron microscopy of bone.

PubMed

Boyde, Alan

2012-01-01

This chapter described methods for Scanning Electron Microscopical imaging of bone and bone cells. Backscattered electron (BSE) imaging is by far the most useful in the bone field, followed by secondary electrons (SE) and the energy dispersive X-ray (EDX) analytical modes. This chapter considers preparing and imaging samples of unembedded bone having 3D detail in a 3D surface, topography-free, polished or micromilled, resin-embedded block surfaces, and resin casts of space in bone matrix. The chapter considers methods for fixation, drying, looking at undersides of bone cells, and coating. Maceration with alkaline bacterial pronase, hypochlorite, hydrogen peroxide, and sodium or potassium hydroxide to remove cells and unmineralised matrix is described in detail. Attention is given especially to methods for 3D BSE SEM imaging of bone samples and recommendations for the types of resin embedding of bone for BSE imaging are given. Correlated confocal and SEM imaging of PMMA-embedded bone requires the use of glycerol to coverslip. Cathodoluminescence (CL) mode SEM imaging is an alternative for visualising fluorescent mineralising front labels such as calcein and tetracyclines. Making spatial casts from PMMA or other resin embedded samples is an important use of this material. Correlation with other imaging means, including microradiography and microtomography is important. Shipping wet bone samples between labs is best done in glycerol. Environmental SEM (ESEM, controlled vacuum mode) is valuable in eliminating -"charging" problems which are common with complex, cancellous bone samples.

SEM-induced shrinkage and site-selective modification of single-crystal silicon nanopores

NASA Astrophysics Data System (ADS)

Chen, Qi; Wang, Yifan; Deng, Tao; Liu, Zewen

2017-07-01

Solid-state nanopores with feature sizes around 5 nm play a critical role in bio-sensing fields, especially in single molecule detection and sequencing of DNA, RNA and proteins. In this paper we present a systematic study on shrinkage and site-selective modification of single-crystal silicon nanopores with a conventional scanning electron microscope (SEM). Square nanopores with measurable sizes as small as 8 nm × 8 nm and rectangle nanopores with feature sizes (the smaller one between length and width) down to 5 nm have been obtained, using the SEM-induced shrinkage technique. The analysis of energy dispersive x-ray spectroscopy and the recovery of the pore size and morphology reveal that the grown material along with the edge of the nanopore is the result of deposition of hydrocarbon compounds, without structural damage during the shrinking process. A simplified model for pore shrinkage has been developed based on observation of the cross-sectional morphology of the shrunk nanopore. The main factors impacting on the task of controllably shrinking the nanopores, such as the accelerating voltage, spot size, scanned area of e-beam, and the initial pore size have been discussed. It is found that single-crystal silicon nanopores shrink linearly with time under localized irradiation by SEM e-beam in all cases, and the pore shrinkage rate is inversely proportional to the initial equivalent diameter of the pore under the same e-beam conditions.

Structural, morphological and gas sensing study of zinc doped tin oxide nanoparticles synthesized via hydrothermal technique

NASA Astrophysics Data System (ADS)

Singh, Davender; Kundu, Virender Singh; Maan, A. S.

2016-07-01

The pure and Zn-doped SnO2 nanoparticles were prepared successfully by hydrothermal route on large scale having different doping concentration of zinc from 0 to 0.20%. The calcined nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) for structural and morphological studies. XRD analyses reveal that the nanoparticles of these doping concentrations are polycrystalline in nature and existed as tetragonal rutile structure, SEM study of images confirms the existence of very small, homogeneously distributed, and spherical nanoparticles. The particles size of the nanoparticles was calculated by Scherrer formula and was found in the range of 9-21 nm. The presence of dopant (i.e. zinc) and formation of Sn-O phase and hydrous nature of Zn-doped SnO2 nanoparticles are confirmed by EDX and FTIR study. The gas sensing properties of pure and Zn-doped SnO2 nanoparticles were investigated for various concentrations of methanol, ethanol and acetone at different operating temperatures and it has been found that with doping concentration of zinc (x = 0.20%) shows the maximum response 78% to methanol, 65% to ethanol and 62% to acetone respectively at different operating temperature within the measurement limit for a concentration of 100 ppm of each gases.

High pressure infiltration sintering behavior of WC-Co alloys

NASA Astrophysics Data System (ADS)

Fan, Xiaoqin; He, Duanwei; Wang, Pei; Li, Dong; Liu, Yinjuan; Ma, Dejiang; Du, Yanchun; Gao, Shangpan; Kou, Zili

2016-10-01

In this paper, two average tungsten carbide particle sizes of 2, 0.5 μm are placed respectively, in contact with a WC-16Co substrate, pressed at the pressure of 4.5-5.5 GPa, and heated to temperatures ranging from 1350°C to 1500°C in a large-volume cubic press. During the process Co was forced out of the WC-16Co substrate into the compressed powder. The resulting infiltrated samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), Vickers hardness and cutting performance tests. The results of XRD confirmed that the sintered bulks have WC and Co phases. The scanning electron microscopy (SEM) analysis reveals that the WC grains in well-sintered alloys are round in shape and cobalt with lower content is uniformly dispersed in the WC grain boundaries. The sintered sub-micron WC-Co alloy with a cobalt content of 3.8 wt% exhibits a prominent combination of high hardness value of 23.1 GPa and a large fracture toughness value of 8.6 MPa m½. The high-speed cutting tests indicating its cutting performance is significantly superior to the commercial YG6X (WC-6 wt%Co with WC grain size of 0.5 μm).

Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

NASA Astrophysics Data System (ADS)

Razavizadeh, Mahmoud; Jamshidi, Masoud

2016-08-01

Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

Degradation of all-vanadium redox flow batteries (VRFB) investigated by electrochemical impedance and X-ray photoelectron spectroscopy: Part 2 electrochemical degradation

NASA Astrophysics Data System (ADS)

Derr, Igor; Bruns, Michael; Langner, Joachim; Fetyan, Abdulmonem; Melke, Julia; Roth, Christina

2016-09-01

Electrochemical degradation (ED) of carbon felt electrodes was investigated by cycling of a flow through all-vanadium redox flow battery (VRFB) and conducting half-cell measurements with two reference electrodes inside the test bench. ED was detected using half-cell and full-cell electrochemical impedance spectroscopy (EIS) at different states of charge (SOC). Reversing the polarity of the battery to recover cell performance was performed with little success. Renewing the electrolyte after a certain amount of cycles restored the capacity of the battery. X-ray photoelectron spectroscopy (XPS) reveals that the amount of surface functional increases by more than a factor of 3 for the negative side as well as for the positive side. Scanning electron microscope (SEM) images show a peeling of the fiber surface after cycling the felts, which leads to a loss of electrochemically active surface area (ECSA). Long term cycling shows that ED has a stronger impact on the negative half-cell [V(II)/V(III)] than the positive half-cell [V(IV)/V(V)] and that the negative half-cell is the rate-determining half-cell for the VRFB.

Hot-corrosion of AISI 1020 steel in a molten NaCl/Na2SO4 eutectic at 700°C

NASA Astrophysics Data System (ADS)

Badaruddin, Mohammad; Risano, Ahmad Yudi Eka; Wardono, Herry; Asmi, Dwi

2017-01-01

Hot-corrosion behavior and morphological development of AISI 1020 steel with 2 mg cm-2 mixtures of various NaCl/Na2SO4 ratios at 700°C were investigated by means of weight gain measurements, Optical Microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The weight gain kinetics of the steel with mixtures of salt deposits display a rapid growth rates, compared with the weight gain kinetics of AISI 1020 steel without salt deposit in dry air oxidation, and follow a steady-state parabolic law for 49 h. Chloridation and sulfidation produced by a molten NaCl/Na2SO4 on the steel induced hot-corrosion mechanism attack, and are responsible for the formation of thicker scale. The most severe corrosion takes place with the 70 wt.% NaCl mixtures in Na2SO4. The typical Fe2O3 whisker growth in outer part scale was attributed to the FeCl3 volatilization. The formation of FeS in the innermost scale is more pronounced as the content of Na2SO4 in the mixture is increased.

Corrosion behavior of an HVOF-sprayed Fe3Al coating in a high-temperature oxidizing/sulfidizing environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.

An iron aluminide (Fe3Al) intermetallic coating was deposited onto a F22 (2.25Cr-1Mo) steel substrate using a JP-5000 high velocity oxy-fuel (HVOF) thermal spray system. The as-sprayed coating was examined by electron microscopy and X-ray diffraction and was characterized in terms of oxidation and adhesion. Fe3Al-coated steel specimens were exposed to a mixed oxidizing/sulfidizing environment at 500, 600, 700, and 800DGC for approximately seven days. The gaseous environment consisted of N2-10%CO-5%CO2-2%H2O-0.12%H2S (by volume). All specimens gained mass after exposure to the environment and the mass gains were found to be inversely proportional to temperature increases. Representative specimens exposed at each temperaturemore » were cross-sectioned and subjected to examination under a scanning electron microscope (SEM) and X-ray mapping. Results are presented in terms of corrosion weight gain and corrosion product formation. The purpose of the research presented here was to evaluate the effectiveness of an HVOF-sprayed Fe3Al coating in protecting a steel substrate exposed to a fossil energy environment.« less

Simultaneous Reduction and Functionalization of Graphene Oxide by 4-Hydrazinobenzenesulfonic Acid for Polymer Nanocomposites

PubMed Central

Qiao, Song-Jie; Xu, Xiang-Nan; Qiu, Yang; Xiao, He-Chong; Zhu, Yue-Feng

2016-01-01

Graphene oxide (GO) was functionalized and reduced simultaneously by a new reductant, 4-hydrazinobenzenesulfonic acid (HBS), with a one-step and environmentally friendly process. The hydrophilic sulfonic acid group in HBS was grafted onto the surface of GO through a covalent bond. The successful preparation of HBS reduced GO (HBS-rGO) was testified by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopic (XPS) and thermogravimetric analysis (TGA). The interlayer space of HBS-rGO was increased to 1.478 nm from 0.751 nm for GO, resulting in a subdued Van der Waals’ force between layers and less possibility to form aggregations. The aqueous dispersibility of graphene was improved to 13.49 mg/mL from 0.58 mg/mL after the functionalization. The viscosity of the epoxy resin based HBS-rGO composite could be regulated by an adjustment of the content of HBS-rGO. This study provides a new and applicable approach for the preparation of hydrophilic functionalized graphene, and makes it possible for the application of graphene in some functional polymer nanocomposites, such as specialty water-based coatings. PMID:28344286