International Nuclear Information System (INIS)

Most surface-acoustic-wave and thin-film optical devices are made by the planar fabrication process. The exposure of the pattern in the polymer film is the first and most crucial step in ensuring desired device geometry, dimensional control, and freedom from pattern distortion. The methods of exposing the polymer film include: optical projection, conventional contact printing, conformable photomask contact printing, holographic recording, scanning electron beam lithography, projection electron lithography, and x-ray lithography. In this paper scanning electron beam lithography, conformable photomask contact printing, holographic recording, and x-ray lithography are discussed. In the last section, ion beam etching of relief structures is discussed.

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Multi-kilo-electron-volt x-ray microscopy will be an important laser-produced plasma diagnostic at future megajoule facilities such as the National Ignition Facility (NIF). However, laser energies and plasma characteristics imply that x-ray microscopy will be more challenging at NIF than at existing facilities. We use analytical estimates and numerical ray tracing to investigate several instrumentation options in detail, and we conclude that near-normal-incidence single spherical or toroidal crystals may offer the best general solution for high-energy x-ray microscopy at NIF and similar large facilities. Apertured Kirkpatrick{endash}Baez microscopes using multilayer mirrors may also be good options, particularly for applications requiring one-dimensional imaging over narrow fields of view. {copyright} 1998 Optical Society of America

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We summarize recent developments in x-ray microscopy of polymers by focusing on the characterization of organic electronic devices. The quantitative compositions of model polymer blends have been mapped at a resolution of {approx}35 nm. Since it could be inferred that these devices have structures smaller than 35 nm, quantitative compositional mapping at length scales below the present resolution limit of x-ray microscopy is required. Organic devices thus serve to both highlight the success of NEXAFS microscopy to date, but to also outline the very real need for higher spatial resolution. New approaches to create improved optics or different acquisition modalities are required if x-ray microscopy is to make sustained contributions to such an important area of research as organic devices.

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High-spatial-resolution microfocus-based X-ray imaging technology, both real-time and film, has been used to study the thickness variation that occurs in the oxide core of silver-sheathed BSCCO ribbons produced by the powder-in-tube method. This thickness variation (also called ``sausaging``) occurs during incremental rolling and degrades the critical current densities of the ribbons. Using X-ray image data the authors determined the onset and severity of sausaging. Onset occurred at a ribbon thickness of 203 {micro}m, and the severity increased with subsequent rolling reductions. Scanning electron microscopy was used to confirm the X-ray image data. X-ray imaging provides several advantages over more traditional methods for characterizing the superconductors such as optical or scanning electron microscopy. The X-ray imaging provides ...

UK PubMed Central (United Kingdom)

San Francisco Bay has been contaminated historically by mercury from mine tailings as well as contemporary industrial sources. Native Spartina foliosa and non-native S....Full Text Available

International Nuclear Information System (INIS)

A study of the thin gold film growth, during the deposition on glass substrate under UHV conditions at low temperatures, is presented. The complementary methods, the atomic force microscopy and grazing incidence x-ray reflectometry, are used for the research. It is shown that due to variation of the time of deposition from 2 to 50 min different kinds of thin Au films nanostructures are obtained: from discontinuous films consisting of isolated islands, via formation of the chains of islands, up to continuous films. (author)

International Nuclear Information System (INIS)

Full text: Institute for Nuclear Research, Pitesti-Mioveni, Romania in direct cooperation with the National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest studied and prepared for coating more than 1000 tiles made of Inconel with 7-9 #mu#m of beryllium for nuclear fusion applications at JET, Culham, UK. The principles of manufacturing processes using thermal evaporation and plasma ignited in pure metal vapors as well as by Thermionic Vacuum Arc (TVA) method and the properties of the Ni and Be coatings are presented. The prepared beryllium layers were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. (authors)

British Library Electronic Table of Contents (United Kingdom)

This paper presents results about the characterisation of the biomass fly ashes sourced from a thermal power plant and from a co-generation power plant located in Portugal, and the study of new cement formulations incorporated with the biomass fly ashes. The study includes a comparative analysis of the phase formation, setting and mechanical behaviour of the new cement-fly ash formulations based on these biomass fly ashes. Techniques such as X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), thermal gravimetric and differential thermal analysis (TG/DTA), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and environmental scanning electron spectroscopy (ESEM) were used to determine the structure and composition of the formulations. Fly ash F1 from the t...

International Nuclear Information System (INIS)

Secondary ion mass spectrometry (SIMS), secondary electron microscopy (SEM) and X-ray analysis have been applied to the measurement of U-bearing particles with the intent of gleaning information concerning their history and/or origin. The lead isotopic abundances are definitive indicators that U-bearing particles have come from an ore-body, even if they have undergone chemical processing. SEM images and X-ray analysis can add further information to the study that may allude to the extent of chemical processing. The presence of 'common' lead that does not exhibit a radiogenic signature is clear evidence of anthropogenic origin. (author)

International Nuclear Information System (INIS)

The transport properties of a 'thin' polycrystalline diamond film are analyzed after the sample exposure to 8.06-keV x-ray radiation. Structure and morphology of the as-grown film have been evaluated by Raman, x-ray diffraction, and scanning electron microscopy techniques. The transport properties have been investigated by measuring dark current-voltage characteristics in the temperature range of 60 to 360 K. Ohmic transport has been evidenced on the as-grown film up to 1.16x10"5 V/cm. After irradiation, nonlinear contributions to the dark current have been evidenced and related to field-assisted thermal ionization of traps. Below 200 K, hopping mechanisms have been observed. Correlations have been found among x-ray irradiation, density of traps involved in the transport processes, and the nonhomogeneous nature of the sample. A simple model of the grain boundary structure is proposed to explain the ...

International Nuclear Information System (INIS)

Iron oxide thin films were prepared by spray pyrolysis technique onto glass substrates from iron chloride solution. They were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and (UV-vis) spectroscopy. The films deposited at T _s #<=# 450 deg. C were amorphous; while those produced at T _s_u_b = 500 deg. C were polycrystalline #alpha#-Fe_2O_3 with a preferential orientation along the (1 0 4) direction. By observing scanning electron microscopy (SEM), it was seen that iron oxide films were relatively homogeneous uniform and had a good adherence to the glass substrates. The grain size was found (by RX) between 19 and 25 nm. The composition of these films was examined by X-ray photoelectron spectroscopy and electron probe microanalysis (EPMA). These films exhibited also a transmittance value about 80% in the ...

International Nuclear Information System (INIS)

Structural relaxation, crystallization and optimisation processes in soft magnetic amorphous alloys based on iron are examined by applying different experimental techniques: X-ray diffraction analysis, high-resolution electron microscopy, measurements of magnetic and electric properties (permeability, after-effect resistivity). The presented results are discussed in terms of annealing out of microvoids, formation of nanocrystalline phase and changes of effective magnetostriction constant. (author)

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The authors study the nonuniformity of a-Si:H films obtained by the method of vacuum condensation, with the help of x-ray small-angle scattering (SLS) and transmission electron microscopy. Films of hydrogenated amorphous silicon are greatest interest, because the electronic properties of this material can be controlled by doping. As a result of the compensation of the ruptured bonds, and possibly, effects of melting, the properties of such films are analogous to those of singlecrystalline silicon. XLS enables a quantitative determination of the prameters of the regions of low electron density (RLD) in such objects.

Science.gov (United States)

We have investigated the nanotexture and crystallographic orientation of aragonite in a coral skeleton using synchrotron-based scanning transmission X-ray microscopy (STXM) and transmission electron microscopy (TEM). Polarization-dependent STXM imaging at 40-nm spatial resolution was used to obtain an orientation map of the c-axis of aragonite on a focused ion beam milled ultrathin section of a Porites coral. This imaging showed that one of the basic units of coral skeletons, referred to as the center of calcification (COC), consists of a cluster of 100-nm aragonite globules crystallographically aligned over several micrometers with a fan-like distribution and with the properties of single crystals at the mesoscale. The remainder of the skeleton consists of aragonite single-crystal fibers in crystallographic continuity with the nanoglobules comprising the COC. Our observation provides information on the nm-scale processes ...

CERN Document Server

Energy Dispersive X-ray Analysis in the Electron Microscope

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Accelerated aging tests on gold bridgewired detonator assemblies to determine compatibility of the Au and Pd-In-Sn solder with the organic explosive, PENT, have revealed an unusual corrosion process. These tests, conducted at 74/sup 0/C and 54/sup 0/C indicated a preferential attack of the gold. A matrix of corrosion test units was established to study this corrosion problem with accelerating temperatures up to 100/sup 0/C. Scanning electron microscopy (SEM), energy dispersive x-ray (EDX), and x-ray diffraction techniques were used to determine the extent of the corrosion and identify the corrosion products. Results indicate the preferential attack of the gold was due to HCN formed by decomposition of the explosive powder (PETN) at high temperatures. Other associated reactions were also observed including subsequent attack of the solder by the gold corrosion product and degradation of the plastic header.

British Library Electronic Table of Contents (United Kingdom)

A novel single-step synthetic method for the preparation of anatase N-doped TiO"2 nanocrystalline at low temperature has been devoleped. The N-doped anatase TiO"2 nanoparticles were synthesized by sonication of the solution of tetraisopropyl titanium and urea in water and isopropyl alcohol at 80^oC for 150min. The as-prepared sample was characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis absorption spectrum. The product structure depends on the reaction temperature and reaction time. The photocatalytic activity of the as-prepared photocatalyst was evaluated via the photodegradation of an azo dye direct sky blue 5B. The results show that the N-doped TiO"2 nanocrystalline prepared via sonication exhibit an excellent photocatalytic...

International Nuclear Information System (INIS)

In this work we report a study of the induced changes in structure and corrosion behavior of martensitic stainless steels nitrided by plasma immersion ion implantation (PI"3) at different previous heat treatments. The samples were characterized by x-ray diffraction and glancing angle x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and potentiodynamic measurements. Depending on the proportion of retained austenite in the unimplanted material, different phase transformations are obtained at lower and intermediate temperatures of nitrogen implantation. At higher temperatures, the great mobility of the chromium yields CrN segregations like spots in random distribution, and the #alpha#"'-martensite is degraded to#alpha#-Fe (ferrite). The nitrided layer thickness follows a fairly linear relationship with the temperature and a parabolic law with the process time. The ...

International Nuclear Information System (INIS)

Particularly high coherence of the x-ray beam is associated, on the ID19 beamline at ESRF, with the small angular size of the source as seen from a point of the sample (0.1-1 #mu#rad). This feature makes the imaging of phase objects extremely simple, by using a 'propagation' technique. The physical principle involved is Fresnel diffraction. Phase imaging is being simultaneously developed as a technique and used as a tool to investigate light natural or artificial materials introducing phase variations across the transmitted x-ray beam. They include polymers, wood, crystals, alloys, composites or ceramics, exhibiting inclusions, holes, cracks, ... . 'Tomographic' three-dimensional reconstruction can be performed with a filtered back-projection algorithm either on the images processed as in attenuation tomography, or on the phase maps retrieved from the images with a reconstruction procedure similar to that used for electron ...

Science.gov (United States)

... The constancy of the X-ray intensity ratio for each element in Table 8 as the X-ray tube settings were changed shows the excellent compensating ...

Science.gov (United States)

This investigation describes the technique for the detection of the X-ray fluorescent radiation

British Library Electronic Table of Contents (United Kingdom)

Homogeneous mixtures of Ce0.8Gd0.2O1.9 (GDC) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) nanopowders were successfully synthesized using induction plasma by axial injection of a solution. The resulting nanocomposite powders consisted of two kinds of nanopowders with different mass ratio of GDC/LSCF, such as 3/7 and 6/4. The morphological features, crystallinity, and the phases of the synthesized powders were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), local energy-dispersive x-ray spectroscopy (EDS) analysis, and x-ray diffraction (XRD). The nanopowders are almost globular in shape with a diameter smaller than 100?nm and their BET specific areas are around 20?m2?g?1. The GDC and LSCF phases are well distributed in the nanopowders. In addition, suspens...

British Library Electronic Table of Contents (United Kingdom)

Herein, we report engineering of nanostructured p-CuIn3Se5/n-CdS heterojunction thin film on a glass substrate, which is prepared at room temperature using simple wet chemical approach involving ion exchange reactions between CdS and Cu^+, In^3^+ and Se^2^- ions in alkaline medium. The uniform deposition of heterojunction thin films is achieved by optimizing the pH, temperature and molarity of the reactant bath. The as-deposited thin-films were annealed at 200^oC in air for 1h and further characterized for structural, optical and electrical properties using UV-Vis spectrophotometer, X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Hall effect for type of conductivity, and I-V measurement to investigate the char...

International Nuclear Information System (INIS)

In this work we investigate an iron oxide thin film grown with atomic layer deposition for a gas sensor application. The objective is to characterize the structural, chemical, and electrical properties of the film, and to demonstrate its gas-sensitivity. The obtained scanning electron microscopy and atomic force microscopy results indicate that the film has a granular structure and that it has grown mainly on the glass substrate leaving the platinum electrodes uncovered. X-ray diffraction results show that iron oxide is in the #alpha#-Fe_2O_3 (hematite) phase. X-ray photoelectron spectra recorded at elevated temperature imply that the surface iron is mainly in the Fe"3"+ state and that oxygen has two chemical states: one corresponding to the lattice oxygen and the other to adsorbed oxygen species. Electric conductivity has an activation energy of 0.3-0.5 eV and almost Ohmic current-voltage dependency. ...

British Library Electronic Table of Contents (United Kingdom)

Multiwall carbon nanotubes (MWCNTs) were functionalized with a photosensitizer, rosebengal (RB), and folicacid (FA), an anti-cancer drug simultaneously and individually, which was characterized with various analytical instruments like Fourier Transform Iinfrared (FTIR) spectroscopy, UV?Vis spectroscopy, Thermogravimetric analysis (TGA), Photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Transmission electron microscopy (TEM). FTIR spectra confirmed the chemical modification of MWCNT. The chemical functionalization of MWCNT with RB was further supported by UV?Vis and PL spectra.

International Nuclear Information System (INIS)

The low alloy steels were nitrided in the plasma atmosphere generated by using hollow cathode discharge. For comparison, specimens of 40 Cr steel were in two different potential states. One kind is isolated from cathode and anode between them the discharge was created. The other kind is placed on the plate which is connected to the cathode. The nitriding was carried out at different temperatures. The surface morphology, phase of compound layers and microhardness profiles were analyzed. The optical microscopy observation and X-ray diffraction showed that the compound layers were formed in all experiments. The results of the nitriding treatment are weakly dependent on the potentials applied on the specimens.

International Nuclear Information System (INIS)

By the methods of small-angle X-ray scattering and translucent electron microscopy the existence of inhomogeneity of electron density in hydrogenated films of amorphous silicon is confirmed. The decreased density regions are extended and form a branched network of channels oriented mostly by the normal direction to the films surface. The typical size of the decreased density regions network constitutes 10 nm in the 100-800 nm films thickness range. The increase of hydrogen total partial pressure in gas mixture in case of films growth results at first in the decrease of extension of these regions and than to micropores generation in the network nodal points of the decreased electron density regions.

International Nuclear Information System (INIS)

AlN nanocrystalline layers and superstructures are used in the modern optoelectronic technology as reflecting mirrors in semiconductor layers. In the present work the properties of AlN films prepared by sputtering methods from an AlN target in reactive Ar + N plasma were investigated. The characterization was performed with HRTEM, SEM, glancing angle XRD and RBS methods. The present measurements confirmed the polycrystalline structure of AlN layers and enabled the evaluation of their grain size. The roughness and thickness of the layers were additionally determined by ellipsometric and profilometric measurements. (author)

British Library Electronic Table of Contents (United Kingdom)

In this paper we describe a Ni-Sn intermetallic material obtained via template electroplating synthesis. The structure and the morphology of this material are investigated by X ray diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. We demonstrate that Ni-Sn behaves as a sub-micrometric electrode showing a favourable response when cycled in a lithium cell. The results here reported suggest that the template electroplating is a promising synthetic approach that can lead to an optimized structure and morphology of the Ni-Sn electrode, such as to confer it a role of a high capacity anode in advanced lithium ion batteries.

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Not Available

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No abstract prepared.

British Library Electronic Table of Contents (United Kingdom)

Antibacterial activity of Transition metals (Mn, Co) doped ZnO nanopowders prepared by a DC thermal plasma method against Escherichia coli and Staphylococcus aureus are investigated. The phase and morphology studies have been carried out by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) respectively. All the samples of the present investigation are found to have hexagonal wurtzite structure and crystallite sizes are found to vary from 25nm to 30nm. Our bacteriological study showed the enhanced antibacterial activity of transition metals doped ZnO nanoparticles than undoped ZnO indicating the great potential of ZnO nanoparticles in relevant clinical and biomedical applications.

British Library Electronic Table of Contents (United Kingdom)

The present investigation deals with the synthesis of nanostructured nickel ferrite (NiFe2O4) and their liquid petroleum gas-sensing characteristics. The 15-20nm size nickel ferrite has been synthesized at 700degreeC by a simple molten-salt route using sodium chloride as grain growth inhibitor. These nanoparticles exhibit significantly high response towards liquid petroleum gas (LPG) in comparison with ethanol vapor, hydrogen sulfide, ammonia and hydrogen. The gas response towards various gases at their 200ppm concentrations is investigated at 200-450degreeC. Different characterization techniques have been employed, such as differential thermal analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission elec...

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The microstructure of the layers produced by plasma nitriding austenitic stainless steel at different treatment temperatures (400 and 500 C) were studied by transmission electron microscopy (TEM) together with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the microstructures were composed of 'expanded austenite' ({gamma}{sub N}) and {alpha}(ferrite)+CrN following plasma nitriding at lower and higher treatment temperatures, respectively. The former contains stacking faults and deformed twin substructures, while the latter is made up of colonies displaying a lamellar structure. Kurdjumov-Sachs or Nishiyama-Wassermann orientation relationships between the {alpha} and CrN layer were observed. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The ball-milling method was used to produce Mg-50 wt.% ZrFe{sub 1.4}Cr{sub 0.6} composite. The thermodynamic, kinetic, and cycling properties, as well as the resistance to oxidation were examined. This composite possesses excellent kinetic properties, even at moderate temperature. Scanning electron microscopy, energy-dispersive spectrum, transmission electron microscopy and X-ray diffraction were used to characterize the composite before and after hydriding. The fine ZrFe{sub 1.4}Cr{sub 0.6} particles covering Mg particles acting as a ''catalytic film'', a significant amount of imperfections and some alloy powder in the Mg matrix introduced by ball milling all contributed to the enhanced absorption/desorption rate. (orig.)

British Library Electronic Table of Contents (United Kingdom)

A study of the stability of conducting fabrics of polyester (PES) coated with polypyrrole/PW12O40^3^- (organic/inorganic hybrid material) in different pH solutions (1, 7, 13) has been done. Washing tests were also done in views of its possible application in electronic textiles such as antistatic clothing. X-ray photoelectron spectroscopy (XPS) studies have been done to quantify the amount of counter ion that remains in the polymer matrix and determine the doping ratio (N^+/N) after the different tests. Scanning electron microscopy (SEM) was also used to observe morphological differences after the different tests. Surface resistivity changes were measured by means of electrochemical impedance spectroscopy (EIS). Scanning electrochemical microscopy (SECM) was employed to measure changes in ...

International Nuclear Information System (INIS)

The sections and provisions of the X-ray Ordinance of January 8, 1987 are discussed which are of relevance to dental radiology. (DG).

Energy Technology Data Exchange (ETDEWEB)

An automated Time Resolved Aerosol Collector (TRAC) has been developed for sequential sampling of field-collected aerosols for laboratory-based Computer Controlled Scanning Electron Microscopy/Energy Dispersed X-ray (CCSEM/EDX) single particle analysis. The collector is optimized for use of grid-supported 20 nm carbon films as deposition substrates. The carbon films have low enough X-ray background to permit EDX analysis down to 0.1-0.2 ?m particles, including detection of low-Z elements: C, N, & O. The TRAC provides unattended sampling onto a set of 151 individual grids, at sequential time intervals as short as 1 min. After collection, the samples are sealed and refrigerated pending analysis. The utility of the TRAC-CCSEM/EDX approach is exemplified using the aerosol samples collected during the Texas 2000 Air Quality Studies (Aug. 15 ? Sept. 15, 2000). We are able to quantitatively follow the time evolution in the ...

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Silver silica nanocomposites were obtained by the sol-gel technique using tetraethyl orthosilicate (TEOS) and silver nitrate (AgNO{sub 3}) as precursors. The silver nitrate concentration was varied for obtaining composites with different nanoparticle sizes. The structural and microstructural properties were determined by x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopic (XPS) studies were done for determining the chemical states of silver in the silica matrix. For the lowest AgNO{sub 3} concentration, monodispersed and spherical Ag crystallites, with an average diameter of 5 nm, were obtained. Grain growth and an increase in size distribution was observed for higher concentrations. The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5-10 nm is studied. For decreasing nanoparticle ...

International Nuclear Information System (INIS)

Iron oxide thin films have been obtained by spray pyrolysis using 100% methanolic and ethanolic solutions of iron tri-chloride. The films were deposited onto ITO-coated glass substrates. The preparative conditions have been optimized to obtain compact, pin-hole-free and smooth thin films which are adherent to the substrate. The structural, morphological and compositional characterizations have been carried out by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The films deposited using ethanolic solution results into pure hematite; #alpha#-Fe_2O_3 thin films, however, films deposited using methanolic solution consists of hematite and maghemite-c phases of iron oxide. The films are nanocrystalline with particle size of 30-40 nm. The optical absorbance of the film was of the order of 10"5 cm"-"1. The optical band gap of films was found to be 2.26 and 2.20 eV for the films deposited using ...

International Nuclear Information System (INIS)

Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e., the self-ions, are used during deposition. Cu films were deposited on SiO_2 substrates at room temperature using 1% Cu self-ions with an energy ranging between 0--4 keV. We studied the microstructures of the Cu films using x-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated x-ray intensity ratio I(111)/I(200) reaches its maximum value indicating a strong left-angle 111 right-angle texture, while the impurity concentration and resisitivity are minimum. The correlation between the structural, compositional and ...

Science.gov (United States)

Ion bombardment during deposition can significantly modify the film properties. In the partially ionized beam deposition, ions derived from the depositing material, i.e., the self-ions, are used during deposition. Cu films were deposited on SiO{sub 2} substrates at room temperature using 1% Cu self-ions with an energy ranging between 0--4 keV. We studied the microstructures of the Cu films using x-ray diffraction and transmission electron microscopy, measured the impurity level inside the films using secondary ion mass spectrometry, and performed the resistivity measurements using a four point probe. The results indicate that there is an optimum ion energy around 2 keV at which, the integrated x-ray intensity ratio {ital I}(111)/{ital I}(200) reaches its maximum value indicating a strong {l angle}111{r angle} texture, while the impurity concentration and resisitivity are minimum. The correlation between the structural, ...

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The finest particle size fractions ({le} 25 {mu}m) in four fly ash samples from fluidised bed combustion of three biomass based fuels and a municipal solid waste fuel were size separated using a centrifugal SPLITT fractionation cell. The ashes were separated into different size fractions and the cadmium concentration, partition and speciation in each separated fraction were then investigated in relation to their possible leaching. The fractionation was evaluated by environmental scanning electron microscopy, which also provided indications of the associations between Cd and other main elements on the particles through the use of X-ray fluorescence mapping. The total concentration of Cd in each fraction was determined by AAS analysis which showed different dependence on the ash particle size in the case of biomass or waste fuels. In addition, the speciation of Cd in each fraction, investigated by sequential chemical extractions and ...

International Nuclear Information System (INIS)

A possible novel application of hard x-ray emitted during laser-plasma interaction was discussed. The authors established an Optical Transform Function to study the joint effect of the spectral distribution and temporal profile of the laser-produced x-ray on x-ray phase imaging. Though the laser-produced x-ray pulse duration is short and incoherent, the analysis confirms that the current x-ray phase imaging theory still holds for laser-produced x-ray phase imaging

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Performance of SRF cavities are limited by non-linear localized effects. The variation of local material characters between "hot" and "cold" spots is thus of intense interest. Such locations were identified in a BCP-etched large-grain single-cell cavity and removed for examination by high resolution electron microscopy (SEM), electron-back scattering diffraction microscopy (EBSD), optical microscopy, and 3D profilometry. Pits with clearly discernable crystal facets were observed in both "hotspot" and "coldspot" specimens. The pits were found in-grain, at bi-crystal boundaries, and on tri-crystal junctions. They are interpreted as etch pits induced by surface crystal defects (e.g. dislocations). All "coldspots" examined had qualitatively low density of etching pits or very shallow tri-crystal boundary junction. EBSD revealed the crystal structure surrounding the pits via crystal phase orientation mapping, while 3D ...

International Nuclear Information System (INIS)

Al, Au, Ti/Al and Ti/Au contacts were prepared on n-GaN and annealed up to 900 deg. C. The structure, phase and morphology were studied by cross-sectional transmission and scanning electron microscopy as well as by X-ray diffraction (XRD), the electrical behaviour by current-voltage measurements. It was obtained that annealing resulted in interdiffusion, lateral diffusion along the surface, alloying and bowling up of the metal layers. The current-voltage characteristics of as-deposited Al and Ti/Al contacts were linear, while the Au and Ti/Au contacts exhibited rectifying behaviour. Except the Ti/Au contact which became linear, the contacts degraded during heat treatment at 900 deg. C. The surface of Au and Ti/Au contacts annealed at 900 deg. C have shown fractal-like structures revealed by scanning electron microscopy. Transmission electron microscopy and XRD investigations of the Ti/Au contact ...

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In this paper, the influence of plasma nitriding at temperature 720 deg. C for 20 h on the surface microstructure and interface microstructure of electroplated chromium coating was investigated. In these conditions, interdiffusion, mixing and reaction phenomena of elements originating from the substrate and coating material are more likely to occur, thus increasing the bonding strength between the coating and carbon steel substrate. The change of the structures from the substrate side to the coating surface, and the effect of the substrate steel on the interface structure were studied by cross-sectional transmission electron microscope observation (XTEM). The nitride layer formed on the surface was analyzed by X-ray diffraction method (XRD). After treatment at above conditions a 6-7 {mu}m thick nitride compound layer was formed in surface region and the same thick carbide compound layer was also formed in the interface region between electroplated chromium coating ...

International Nuclear Information System (INIS)

We have investigated the microstructure evolutions in the Ti17 near #beta# titanium alloy during heat treatments. The phase transformation has first been studied experimentally by combining X-ray diffraction analysis, electrical resistivity and microscopy observations. From a series of isothermal treatments, a IT diagram has been determined, which takes into account the different morphologies. Then, a Johnson-Mehl-Avrami-Kolmogorov (JMAK) model has been successfully used to describe the phase transformation kinetics during either isothermal or cooling treatments. Finally, the coupling of the JMAK model to the finite element software ZeBuLoN allowed us to investigate the evolution of the spatial distribution of the different morphologies during the cooling of an aircraft engine shaft disk after forging.

British Library Electronic Table of Contents (United Kingdom)

The thermal stability of nanoscale grains in cryomilled aluminum powders containing 1% diamantane was investigated. Diamantane is a diamondoid molecule consisting of 14 carbon atoms in a diamond cubic structure that is terminated by hydrogen atoms. The nanostructures of the resulting cryomilled powders were characterized using both transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The average grain size was found to be on the order of 22?nm, a value similar to that obtained for cryomilled Al without diamantane. To determine thermal stability, the powders were heated in an inert gas atmosphere at constant temperatures between 423 and 773?K (0.51T m to 0.83T m) for exposure times of up to 10?h. The average grain size for all powders containing diamantane was obse...

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Biosorption of elements is a little understood phenomenon exhibited by some types of even nonliving microbial biomass. A common fungus Rhizopus arrhizus has been reportd to take up uranium from adqueous solutions to the extent of 180 mg U/sup 6 +//g. The mechanism of uranium sequestering by this type of biomass was studied by using experimental techniques such as electron microscopy, x-ray energy dispersion analysis, IR spectroscopy, and supporting evidence was obtained for a biosorption mechanism consisting of at least three processes. Uranium coordination and adsorption in the cell-wall chitin structure occur simultaneously and rapidly whereas precipitation of uranylhdroxide within the chitin microcrystalline cell-wall structure takes place at a lower rate. Interference of Fe/sup 2/ and Zn/sup 2 +/ coions with uranium biosorption is indicated.

Energy Technology Data Exchange (ETDEWEB)

Reduction of silver myristate (AgMy) under mild thermal reaction conditions in a dipolar aprotic solvent i.e. N, N-dimethylformamide (DMF) has been carried out. UV-visible absorption measurements of dried and re-dispersible brown flocculants showed broad features of surface plasmon resonance (SPR) due to silver nanoparticles. The freshly isolated particles showed absorption bands at 414 and 485 nm, respectively, due to inter-particle coupling or clustering of silver ions and silver atoms. X-ray diffraction (XRD) pattern of fcc zero-valent silver resulted in crystallite size of about 10 nm. Scanning electron microscopy (SEM) revealed formation of rod shaped silver with increasing reaction temperature. Thermal analysis (TGA) showed about 10% weight loss due to organic capping.

British Library Electronic Table of Contents (United Kingdom)

Bilayers of pure palladium and gold films were evaporated alternatively on (100) and (111) monocrystalline silicon substrates. After annealing, in a vacuum furnace from 100 to 650degreeC during 30min, the growth sequence of the Pd2Si and PdSi phases that evolved as the result of the diffusion reaction was examined by means of Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), whereas the surface morphology was investigated by scanning electron microscopy (SEM) technique. The effect of the intermediate gold layer is investigated in order to test its effectiveness as barrier for Cu and Si atoms interdiffusion and its influence on the morphology of the formed palladium silicides. The effect of substrate orientation on the palladium silicides growth and formation was also e...

British Library Electronic Table of Contents (United Kingdom)

The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process cou...

International Nuclear Information System (INIS)

The constituent phases and associated deformed microstructure of the quenched Ti-xNb-(0.5-1.5) at.% Si alloy consisting of non-cytotoxicity elements, where x = 24-30 at.%, were investigated to provide pseudoelasticity for biomedical and sensor applications. Optical microscopy revealed that stress-induced martensitic transformation takes place during the deformation in the present alloys. It is confirmed from the X-ray diffraction results of the deformed specimens that the crystal structure of the stress-induced martensite phase is the orthorhombic so-called #alpha#'' structure. Within the alloys having #beta#(bcc) phase studied Nb-poor region appeared to exhibit a dominant behavior for stress-induced martensitic transformation than Nb-rich region. This result suggests that metastable #beta# phase is superior to stable #beta# phase for the occurrence of stress-induced martensitic transformation in the present alloy system.

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Ag nanoparticles were prepared in a water-phase system with a mixture of silver-ammonia complex, sodium borohydride, and lauric acid according to molar feed ratio of approximately 6:3:1. The mechanism of preparation and separation by chemical reduction-protection method was explored. The as-synthesized Ag nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis spectroscopy, respectively. It was found that the size of high purity Ag particles was ranging from 30 to 50 nm with slight agglomeration. In addition, the as-synthesized wet Ag nanoparticles were dispersed stably in organic vehicle to formulate electrically conductive nanopaste. Upon direct-written and sintered, the array pattern of the nanopaste with the resolution of about 30 {mu}m was achieved with the electrical resistivity in the order of magnitude of 10{sup -5} {Omega} cm.

British Library Electronic Table of Contents (United Kingdom)

The growth of silver chloride nanoparticles on ancient textile was achieved by sequential dipping steps in alternating bath of potassium chloride and silver nitrate under ultrasound irradiation. The effect of ultrasound irradiation and sequential dipping steps in growth of the AgCl nanoparticles has been studied. These systems depicted a decrease in the particles size accompanying a decrease in the sequential dipping steps. The samples were characterized with powder X-ray diffraction (XRD) and scanning electron microscopy. XRD analyses indicated that the prepared AgCl nanoparticles on fiber were crystalline. The textile samples containing AgCl nanoparticles were tested for their antibacterial efficacy against Escherichia coli and were found to possess significant antibacterial activity.

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Microalloyed or high strength low alloy (HSLA) steels are carbon-manganese steels containing small amounts of Nb, V or Ti. The excellent mechanical properties of these alloys, particularly high yield strength, usually obviate the need for expensive quench and tempering operations. Furthermore, the presence of a significant amount of nitride-forming elements in some microalloyed steels has generated interest in the applicability of these alloys as a new generation of nitriding steels. In this paper, a study of the plasma nitriding behaviour of a commercially available microalloyed steel MAXIMA{sup TM} is reported. A comparison is made with a traditional quenched and tempered nitriding steel (En19), plasma nitrided under similar conditions. Optical and scanning electron microscopy in conjunction with microhardness measurements and X-ray diffraction were utilized to characterize the nitrided surfaces. The observed differences in the thickness and ...

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Pd-induced surface structures on Si(1 1 3) have been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In the initial process of the Pd adsorption below 0.10 ML, Pd silicide (Pd{sub 2}Si) clusters are observed to form randomly on the surface. By increasing the Pd coverage to 0.10 ML, the clusters cover the entire surface, and an amorphous layer is formed. After annealing the Si(1 1 3)-Pd surface at 600 deg. C, various types of islands and chain protrusions appears. The agglomeration, coalescence and crystallization of these islands are observed by using high temperature (HT-) STM. It is also found by XPS that the islands correspond to Pd{sub 2}Si structure. On the basis of these results, evolution of Pd-induced structures at high temperatures is in detail discussed.

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Samples of austenitic stainless steel AISI 316 were nitrided using the cathodic cage technique with the addition of methane in the nitriding atmosphere. The aim was to study the influence of this technique in reducing the precipitation of chromium nitrite and in improving the wear resistance. The results show that there was a significant improvement in such properties when compared to the results of ionic plasma nitriding. Formation of a double layer, one more internal composed of carbon and another with high nitrogen content, was confirmed by Scanning Electron Microscopy (SEM). The microhardness profile of the layer showed an increase in hardness values and a larger uniformity, while X-ray analysis showed less chromium nitriding precipitation when compared with results obtained for samples treated using ionic plasma nitriding.

International Nuclear Information System (INIS)

Microstructure and properties of a Mg AZ31B laser beam weld without filler are studied using electron microscopy, X-ray diffraction and mechanical tests. The microstructure of the weld is characterized by a narrow heat affected zone, columnar grains and precipitate coarsening in the fusion zone. Texture in the fusion zone is significantly different from the texture of the base material. The residual stress distribution observed is similar at the top and the bottom of the weld, maximum tensile residual stress values are observed in the fusion zone. Tensile tests reveal differences in the mechanical behavior of the fusion zone and the parent material, which can be related to the differences of texture and the resulting deformation mechanisms.

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Regularities of deformation-induced dissolution of a surface layer of iron oxides in matrixes of iron-based alloys with bcc and fcc lattices have been studied by the methods of M?ssbauer spectroscopy, transmission electron microscopy, and X-ray diffraction. A method of producing iron alloys strengthened by dispersed oxide nanoparticles and alloyed with elements possessing a high affinity to oxygen (titanium and yttrium) has been proposed, which implies a dynamic dissolution of a surface layer of iron oxides upon strong cold deformation and a precipitation of secondary yttrium and titanium nanooxides upon a subsequent high-temperature sintering of mechanically alloyed powders. There has been demonstrated a possibility of oxide strengthening of pure iron upon its interaction with air without...

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Cold spray was employed as a novel low temperature approach to deposit titanium dioxide (TiO{sub 2}) photocatalytic film. The film microstructure was characterized using X-ray diffraction and scanning electron microscopy. The photocatalytic performance was examined through acetaldehyde degradation under ultraviolet illumination. Results showed that TiO{sub 2} film was successfully deposited on substrate surface through cold spray. The film thickness reached up to 15 {mu}m. The film presented a rough surface and porous structure. Owing to the low temperature of spray powder, no phase and particle size changes occurred to TiO{sub 2} during deposition. It was found that the cold-sprayed TiO{sub 2} film was active for photodegradation of acetaldehyde.

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Interest in the tribological properties of plasma nitriding has increased substantially over the past years because plasma nitriding provides a high nitride depth and improved hard facing. The present study examines the tribological properties of AISI H11 plasma nitrided, hot-worked steel. Different nitriding temperatures and durations were considered. Characterization of the composite structures was investigated with wear tests, x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and microhardness tests. The depth profile of the nitrided zone was measured using the nuclear reaction analysis (NRA) technique. Plasma nitriding affected the microhardness, wear properties, and morphology considerably. Increase in process temperature increased the nitride zone depth.

British Library Electronic Table of Contents (United Kingdom)

In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative proced...

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Nd{sub 40}Fe{sub 30}Al{sub 10}Co{sub 15}B{sub 5} alloys were fabricated by high energy ball milling method under various conditions. Microstructure of the alloys was investigated by X-ray diffraction and electron microscopy techniques. Magnetic properties were characterized by hysteresis and thermomagnetic measurements. The high coercive fields up to 2.36 T have been observed on the samples consisting of Nd{sub 2}(Fe,Co,Al){sub 14}B, Nd{sub 6}(Fe,Co,Al){sub 14} and Nd crystallites imbedded in a residual amorphous matrix.

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Passive films formed on Alloy 690 in high-temperature alkaline environments were investigated by potentiodynamic polarization, X-ray photoelectron spectroscopy, transmission electron microscopy and Mott-Schottky approach. Passive current density and donor density of the passive films increase with increasing temperature, due to increased diffusion rates of metallic ions and dehydration of hydroxide phases. The passive films show a duplex structure including an inner layer of fine-grained Cr oxide or spinel oxide and an outer layer of Ni-Fe spinel oxide and Ni hydroxide. A growth model of the passive films on Alloy 690 in high-temperature alkaline environments is proposed and discussed.

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Nanosized CaSnO{sub 3} is synthesized by a hydrothermal process and characterized by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The SEM observation shows the sample has a porous flowerlike morphology. The electrochemical results exhibit that the stable and reversible capacity of 547 mAh g{sup -1} is obtained after 50 cycles at 60 mA g{sup -1} (0.1 C) and the corresponding charge capacity is determined to be 316 mAh g{sup -1} at the current density of 2.5 C. Cyclic voltammetry and electrochemical impedance spectroscopy data are analyzed to complement the galvanostatic results. The observed excellent performance is attributed to the porous structure and large surface area of flowerlike CaSnO{sub 3}.

British Library Electronic Table of Contents (United Kingdom)

To improve the friction and wear behavior of carbon fabric reinforced polymer composites (CFRP), nano-SiO2 was deposited on the fabric surface. The friction and wear behavior of the resulting composites were investigated on a model ring-on-block test rig. Experimental results revealed that fiber surface treatment contributed to largely improve the tribological properties of the CFRP composites. Scanning electron microscope (SEM) investigation showed that the worn surface of the surface modified CFRP composite was smoother under given load and sliding rate. Field emission scanning electron microscopy (FESEM), FTIR and X-ray photoelectron spectroscopy (XPS) studies of the carbon fiber surface showed that nanostructured Sio2 thin film can be obtained by SiO2 sols deposition, which improved th...

International Nuclear Information System (INIS)

Recent research carried out in laboratories showed that Saddle field neutral fast atom beam source is a promising method for nitriding of stainless steel. In the present work, the effect of treatment time on the microstructural and mechanical properties of plasma-nitrided stainless steel sample was investigated by this new method. Plasma nitriding was carried out at 420 deg. C and at a pressure of 0.1 Pa for a time range of 1 to 12 h. SEM-EDX, microhardness tests, optical microscopy and X-ray diffraction (XRD) were used to evaluate the mechanical and structural properties of the nitrided layer. It was found that nitriding time has a pronounced effect on the structural and mechanical properties of low-temperature plasma-nitrided samples and produced a precipitation-free thin hard nitrided layer within a short processing time.

British Library Electronic Table of Contents (United Kingdom)

In this work AISI 1045 steel were duplex treated via plasma nitriding of chromized layer. Samples were pack chromized by using a powder mixture consisting of ferrochromium, ammonium chloride and alumina at 1273K for 5h. The samples were then plasma-nitrided for 5h at 803K and 823K, in a gas mixture of 75%N2+25%H2. The treated specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and Vickers micro-hardness test. The thickness of chromized layer before nitriding was about 8mm and it was increased after plasma nitriding. According to XRD analysis, the chromized layer was composed of chromium and iron carbides. Plasma nitriding of chromized layer resulted in the formation of chromium and iron nitrides and carbides. The hardness of the duplex layer...

International Nuclear Information System (INIS)

The intensity of superstructure reflections and associated diffuse scattering from In_0_._5Ga_0_._5P and In_0_._5Al_0_._5P epitaxic layers grown on (001) GaAs substrates was mapped in reciprocal space. The Warren-Cowley short-range-order parameters were obtained through the usual process for evaluating Fourier coefficients. Varying values for the correlation length in different directions indicate how group III atoms stack up in ordered states. The resultant structure with long-range order confirms the hypothesis made on the basis of electron diffraction and high-resolution transmission electron microscopy studies. (orig.).

British Library Electronic Table of Contents (United Kingdom)

A microanalytical characterization of cast magnesium alloys of eutectic origin based on the Mg?Al?Ca ternary matrix system has been carried out in order to investigate the influence of alloying elements on their microstructure as well as microchemistry-processing-microstructural relations using structure-sensitive techniques of electron microscopy, mechanical spectroscopy (internal friction), X-ray diffractometry, and advanced microanalytical methods including electron probe compositional analysis. Following the data obtained here there is direct correlation of microstructure with creep properties of the new experimental magnesium alloys. The creep and heat-induced properties of the multicomponent magnesium alloys containing low range of inexpensive additions of titanium (0.07?0.2%) or str...

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The electroless nickel plating/poly(dl-lactide-co-glycolide) composite coating (EN-plating/PLGA composite coating) was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy AZ81 to double control the corrosion and drug release in the hanks' solution. The EN-plating was fabricated on the MAO coating to improve the corrosion resistance by overlaying most pores and micro-cracks on the surface of the MAO film. Meanwhile, a double layered organic poly(dl-lactide-co-glycolide)/paclitaxel (PLGA/PTX) drug releasing coating with a top layered PLGA drug controlled releasing coating on EN plating was prepared to control the drug release rate by adjusting the different lactide: glycolide (LA:GA) ratio of PLGA. Scanning electron microscopy (SEM) and the X-ray powder dif...

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Biosorption of lead from aqueous solutions by living and immobilized cell of C. freundii was examined as a function of metal concentration in a batch laboratory bioreactor. Lead concentrations were analyzed using Atomic Absorption Spectrophotometer (AAS). X-ray Energy Dispersion (EDX) analyses were made in order to determine the accumulation of lead on the cells and shell surfaces. Before and after the experiments the biomaterials and adsorbents were examined by Scanning Electron Microscopy (SEM). Biosorption was detected over a range of initial lead concentrations from 25{times}10{sup -3} to 200{times}10{sup -3} kg/m{sup 3}. 15 refs., 4 figs.

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A novel liquid phase alkylation of aniline with methanol over Zn/Cu salts modified kaolin assisted with a pair of porous carbon electrode in slurry-bed reactor under constant current intensity, room temperature and atmospheric pressure was reported. The Zn/Cu salts modified kaolin catalysts were synthesized and characterized by infrared spectrometer (IR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the transition metals were completely supported on kaolins structure and formed a pored one. The effect parameters, such as initial pH, electrolysis time, metal ratio with kaolin and salts composition in this electrochemical catalytic system, were studied. The procedure was inspected by ultraviolet-visible spectrum (UV-vis), and the product distributi...

International Nuclear Information System (INIS)

A brief description of the physical process of dose enhancement effects produced by X-ray radiation on materials is given, with emphasis on the influence on electronic devices. The damages caused by X-ray radiation dose enhancement is more serious than that of #gamma#-ray with higher energy.

UK PubMed Central (United Kingdom)

The issue of beam-induced damage on diffractive hard X-ray optics is addressed. For this purpose a systematic study on the radiation damage induced by a high-power X-ray beam is carried out in both...Full Text Available

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High interelectrode voltage peaks have been observed simultaneously with the emission of hard X-ray bursts from a flash X-ray tube. The magnitude of the voltage peaks may exceed twice the initial charging voltage. It has also been observed that the discharge emits bursts of X-and P-band microwaves radiation which are coincident with the emission of the hard X-ray bursts. The results indicate that the microwaves and X-rays have a common origin in discharge plasma movements and an acceleration model for electrons in the plasma is presented as one possible explanation of the observed phenomena.

International Nuclear Information System (INIS)

... obtain the film thickness for a given x-ray intensity ratio. 2.3 ANALYSING FOR

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The X-ray properties of the main sequence Be stars conclude that they are a widely separated binary system containing an accreting neutron star.

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ZnO thin films were electrodeposited in aqueous solution on gilded p-type Si wafer substrates. Thermal treatments were carried out on different films in Ar atmosphere at different temperatures, between 200 and 600 {sup 0}C. Surface morphology studies using scanning electron microscopy and atomic force microscopy show a smooth surface for an annealing temperature of 400 {sup 0}C with a roughness mean square value of about 15 nm and a precipitation of ZnO microcrystals on the deposit surface at 600 {sup 0}C. X-ray diffraction experiments reveal a decrease in the c-parameter value from 5.223 to 5.206 A after treatment at 600 {sup 0}C, due to the removal of hydrogen from the film. Raman spectroscopy analyses show an improvement in the crystal quality of the film and a decrease in the compressive stress inside the deposit. Photoluminescence observations reveal an important change in the UV emission band after annealing at 200 ...

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This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N{sub 2}/H{sub 2}) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole ...

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The formation of textured YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (123) from a liquid phase according to the peritectic reaction Y{sub 2}BaCuO{sub 5} (211) + liquid {yields} 123 was analyzed using real-time analysis techniques of high-temperature X-ray diffraction, high-temperature optical microscopy, and environmental scanning electron microscopy (ESEM). Results were coupled with conventional ''post-mortem'' SEM analysis of processed samples at various stages of microstructural development. Observations of 123 formation and growth from the peritectic melt permit the conclusion that the presence of crystalline 211 primarily acts as a source of yttrium. The slow dissolution of 211 into the yttrium deficient liquid phase is the rate controlled step in the formation and growth of the textured 123, rather that its acting as a nucleation site for 123 grains as has been widely assumed. (orig.).

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In this study, WO{sub 3} thin films were grown on glass substrates using an aqueous solution containing tungstate (NH{sub 4}){sub 2}WO{sub 4} as precursor. The substrate temperature incremented from 250 to 500 deg. C, by steps of 50 deg. C. The structural properties were investigated using XRD, atomic force microscopy and scanning electronic microscopy techniques. Microprobe analyses showed that a balanced stoichiometric composition was obtained for thin films prepared at T{sub s} = 350 and 400 deg. C. The X-ray diffraction analyses showed different structure crystallography in function of the substrate temperature. Moreover, films deposited at 400 deg. C were annealed in air for 2 h at 450 and 500 deg. C, respectively and the structural changes due to heat treatment were studied. Finally, the optical properties of these films were carried out using optical measurements of transmittance T({lambda}) and reflectance ...

International Nuclear Information System (INIS)

Zinc oxide thin films were obtained by laser ablation of a Zn target in oxygen reactive atmosphere, the oxygen being supplied either by a standard gas inlet valve or from a radio-frequency (rf) oxygen plasma. Pt-coated silicon and MgO were used as substrates. The influence of the deposition parameters as laser wavelength (266, 355, 1064 nm), laser fluence (1.5-20 J/cm2) and oxygen pressure (1-60 Pa) was studied. The influence of the rf plasma beam addition on the morphological proprieties of zinc oxide films was particularly investigated, simultaneously with several configurations of the direction of the ablation plasma, the rf plasma beam and the substrate. The obtained films, with thicknesses in the range of 50 nm to 1 ?m have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM).

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Dopant-free Bi{sub 2}Ti{sub 2}O{sub 7} thin films with pyrochlore structure and La-doped bismuth titanate thin films have been fabricated by means of chemical solution decomposition, and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy and UV-Vis spectrophotometry in this study. Their photocatalytic activities have been evaluated by photodegrading methyl orange solution, and the optimum processing parameters for the highest photocatalytic activity have been found. Moreover, the effects of La-doping on the phase transformation and the photocalalytic activity have been studied. It has been deduced from the experiment result that substituted La{sup 3+} ions can act as a stabilizer of Aurivillus phase BLT and a grain-growth inhibitor in BLT thin films.

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Powders with nominal compositions (in atomic percent) Ti-48Al and Ti-48Al-2Nb-2Cr were prepared by the plasma rotating electrode process (PREP) and gas atomization (GA) techniques. As-solidified and heat-treated (1000degC per 3 h) powder samples were examined by metallography, scanning electron microscopy, X-ray diffraction and transmission electron microscopy. The microstructures of the powders were characterized as a function of atomization technique, alloy content, powder particle size (solidification rate) and thermal history. All of the as-solidified powders were comprised of disordered [alpha], and ordered [alpha][sub 2]-Ti[sub 3]Al and [gamma]-TiAl. For both alloys, a larger volume fraction of [alpha] and [alpha][sub 2] was observed in the PREP powders relative to GA powders of comparable size. Additionally, for both alloys and both atomization techniques, the volume fraction of [alpha][sub 2] was observed to ...

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The three-dimensional magnetic structure and reversal mechanism of patterned Co/Pt multilayers, were imaged using complementary Lorentz transmission electron microscopy (LTEM) (in-plane component) and magnetic transmission x-ray microscopy (M-TXM) (perpendicular magnetization). The Co/Pt films with perpendicular anisotropy were patterned by ion irradiation through a stencil mask to produce in-plane magnetization in the irradiated regions. The boundaries of the patterns, defined by the transition from out-of-plane to in-plane magnetization, were found to be determined by the stencil mask, whilst the scale of the magnetic reversal by the physical microstructure. The nucleation fields were substantially reduced to 50 Oe for the in-plane regions and 1 kOe for the perpendicular regions, comparing to 4.5 kOe for the as-grown film. The perpendicular reversals were found to always originate at the pattern boundaries.

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The electrochemical method has been used to deposit zinc oxide (ZnO) thin films from aqueous zinc nitrate solution at 80 deg. C onto fluorine doped tin oxide (FTO) coated glass substrates. ZnO thin films were grown between - 0.900 and - 1.025 V vs Ag/AgCl as established by voltammogram. Characterisation of ZnO films was carried out for both as-deposited and annealed films in order to study the effect of annealing. Structural analysis of the ZnO films was performed using X-ray diffraction, which showed polycrystalline films of hexagonal phase with (002) preferential orientation. Atomic force microscopy was used to study the surface morphology. Optical studies identified the bandgap to be {approx} 3.20 eV and refractive index to 2.35. The photoelectrochemical cell signal indicated that the films had n-type electrical conductivity and current-voltage measurements showed the glass/FTO/ZnO/Au devices exhibit rectifying properties. The thickness of ...

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The properties of polycrystalline (Ti, Al)N coatings deposited on non-nitrided, classically plasma-nitrided and low pressure plasma-nitrided AISI H11 steel samples were investigated. The plasma deposition and low pressure plasma nitriding were performed in a Z700-LH magnetron sputter ion plating unit, while a separate unit was used for plasma nitriding of specimens at a pressure of several millibars. The (Ti, Al)N coating was deposited onto all the samples using the same equipment as for the plasma deposition and low pressure plasma nitriding. For the characterization of the composite structures, the following methods were used: scratch test, X-ray diffraction analysis, scanning electron microscopy, scanning tunnelling microscopy and microhardness testing. It was found that plasma nitriding prior to coating deposition strongly affects the growth and properties of hard coatings, such as the microhardness, adhesion, preferred ...

International Nuclear Information System (INIS)

For direct writing of electrically conducting connections and areas into insulating gold oxide thin films a scanning Ar"+ laser beam and a 30 keV Ga"+ focused ion beam (FIB) have been used. The gold oxide films are prepared by magnetron sputtering under argon/oxygen plasma. The patterning of larger areas (dimension 10-100 #mu#m) has been carried out with the laser beam by local heating of the selected area above the decomposition temperature of AuO_x(130-150 C). For smaller dimensions (100 nm to 10 #mu#m) the FIB irradiation could be used. With both complementary methods a reduction of the sheet resistance by 6-7 orders of magnitude has been achieved in the irradiated regions (e.g. with FIB irradiation from 1.5 x 10"7#OMEGA#/#square# to approximately 6 #OMEGA#/#square#). The energy-dispersive X-ray analysis (EDX) show a considerably reduced oxygen content in the irradiated areas, and scanning electron microscopy (SEM), as well as atomic force ...

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Short communication.

International Nuclear Information System (INIS)

Monochromator stabilization (MOSTAB) is a feedback control system to stabilize an x-ray beam of synchrotron radiation. It applies a feedback voltage to a piezo electric transducer attached to a double-crystal monochromator. We developed MOSTAB modules and examined their performances using SPring-8 beamlines. The x-ray beam position stabilization using MOSTAB was realized simultaneously with the x-ray beam intensity stabilization. As an example of its application, we performed EXAFS measurement with MOSTAB. (author)

International Nuclear Information System (INIS)

Short communication.

Science.gov (United States)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

Slovak 1973. 164 p. Czechoslovakia Havranek, E. Bumbalova, A. Svitel,

Science.gov (United States)

... NONDESTRUCTIVE DETERMINATION OF AIRBORNE LEAD PARTICULATES BY THE RADIONUCLIDE X-RAY FLUORESCENCE ANALYSIS. ...

International Nuclear Information System (INIS)

X-ray scattering methods suitable for the investigation of the morphology and chemical composition of self-organized quantum dots and quantum wires are reviewed. Their application is demonstrated in experimental examples showing that a combination of small angle X-ray scattering with high-resolution X-ray diffraction can reveal both the shape and the chemical composition of the self-organized objects. (author)

International Nuclear Information System (INIS)

Published in summary form only.

Science.gov (United States)

Not Available

Science.gov (United States)

in a KDP crystal fed with red light from a Q-s_tched ruby laser. One reason for interest in holograms made with ultraviolet ...

International Nuclear Information System (INIS)

The author's achievements in the title field are summarized and discussed. The following topics are dealt with: (i) principles of radionuclide X-ray fluorescence analysis; (ii) mathematical methods in X-ray fluorescence analysis; (iii) Ross differential filters; (iv) application of radionuclide X-ray fluorescence analysis in the coal industry (with emphasis on the determination of the ash content, sulfur content, and arsenic content of coal); and (v) evaluation of the X-ray fluorescence analyzer from the radiological safety point of view. (P.A.).

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Discusses methods for determining ash content in coal using backscattering in X-ray fluorescence. The following aspects are evaluated: principle of ash content determination, energy sources, factors that influence measurement accuracy, reliability. Types of X-ray fluorescence analyzers developed in Czechoslovakia and manufactured in the Czech Republic are comparatively evaluated. Operation of the RPM 113.1 radionuclide X-ray fluorescence analyzer developed by the PAR company and used for measuring ash content in coal and coal calorific value is discussed. 7 refs.

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Here we examine Fe speciation within Fe-encrusted biofilms formed during 2-month seafloor incubations of sulfide mineral assemblages at the Main Endeavor Segment of the Juan de Fuca Ridge. The biofilms were distributed heterogeneously across the surface of the incubated sulfide and composed primarily of particles with a twisted stalk morphology resembling those produced by some aerobic Fe-oxidizing microorganisms. Our objectives were to determine the form of biofilm-associated Fe, and identify the sulfide minerals associated with microbial growth. We used micro-focused synchrotron-radiation X-ray fluorescence mapping (mu XRF), X-ray absorption spectroscopy (mu EXAFS), and X-ray diffraction (mu XRD) in conjunction with focused ion beam (FIB) sectioning, and highresolution transmission electron microscopy (HRTEM). The chemical and mineralogical composition of an Fe-encrusted biofilm was queried at ...

International Nuclear Information System (INIS)

We present differential scanning calorimetry (DSC), X-ray diffractometry, in situ Moessbauer spectroscopy (MS), and transmission electron microscopy (TEM) studies in Metglas ribbons subjected to different heat treatments. The temperature evolution of the hyperfine field H_h_f(T) and the Curie temperature (T_c) of the amorphous phase are determined. The magnetic field originally present in the amorphous phase has a 'normal' behavior, in the sense that it can be described by the Weiss molecular field theory. The total angular momentum of the iron atoms turns out to be 5/2 and this implies Fe"3"+ in which the electronic spins are uncoupled. When the samples are maintained near T_c (#approx#673 K), three new magnetic phases are detected in the Moessbauer spectra, indicating an onset of a crystallization process well below the first crystallization temperature (T_X_1), as determined by DSC (#approx#820 K). The magnetic behavior of these phases is ...

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In order to understand the chemistry of altermetal dopants in antimony oxide, the detailed structural characterization of two ..beta..-Sb/sub 2/O/sub 4/ compounds is reported, Mo-doped ..beta..-Sb/sub 2/O/sub 4/ (1.5 metal%) and V-doped ..beta..-Sb/sub 2/O/sub 4/ (5 metal%). The methods used to characterize these materials are X-ray and neutron diffraction, scanning electron microscopy, Mo K-edge extended X-ray absorption fine structure spectroscopy, and elemental analysis. The atomic position of each of these dopants in Sb/sub 2/O/sub 4/ is radically different as is the overall effect on the host structure. Molybdenum does not substitute for Sb atoms, rather the Mo atoms are found in channels of electron density formed by Sb/sup 3 +/ lone pairs. The two nearest Sb/sup 3 +/ are absent and the oxygen stoichiometry is preserved. The formula is Sb/sub 1.97/Mo/sub 0.015/O/sub 4/. Vanadium incorporates substitutionally for the ...

International Nuclear Information System (INIS)

Thermo-reactive diffusion chromizing followed by pulsed plasma nitriding were carried out on AISI 52100 and 8620 bearing steels. The chromized samples were pulse-plasma nitrided for 5 h at 500 deg. C in various N_2-H_2 gas mixtures. The coated steels were characterized using scanning electron microscopy, X-ray diffraction and microhardness testing. The unlubricated wear behaviors of only chromized and duplex treated steels were investigated in ball-on-disc system tests at room temperature. X-ray diffraction patterns of the duplex treated samples containing H_2 indicated the formation of dominant CrN and Cr_2N nitrides as well as the formation of Cr_3C_2 and Cr_7C_3 carbides. Gas mixtures in the plasma nitriding, which was performed after chromizing, have a significant influence on the wear rate of the duplex treated steels. The wear and friction tests showed that the lowest friction coefficient and wear rates were observed ...

Science.gov (United States)

The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozyme complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar arrangements of F-actin held ...

Science.gov (United States)

Mesporous anatase-phase TiO(2) hollow spheres with high photocatalytic activity were prepared by hydrothermal treatment and self-transformation of amorphous TiO(2) solid spheres in an NH(4)F aqueous solution. The prepared samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, N(2) adsorption-desorption isotherms and UV-vis absorption spectroscopy. The photocatalytic activity was evaluated by photocatalytic oxidation decomposition of acetone in air under UV irradiation. It is found that F(-) plays an essential role in the formation of TiO(2) hollow spheres. F(-) not only induces the hollowing of TiO(2) solid spheres, but also promotes the crystallization of anatase TiO(2) nanocrystals. A possible formation mechanism for the TiO(2) hollow spheres by localized Ostwald ripening or chemically induced self-transformation is proposed based on the ...

International Nuclear Information System (INIS)

After having discussed the peculiarities of children in X-ray diagnosis the application of the effective as well as the mean equivalent doses as to the determination of the radiation exposure in children is represented. In using computerized tomograms to determine position and extent of an organ the exposure by repeated X-raying was calculated referring to the entrance dose. Entrance dose measurements for all types of X-ray examination in hospitals and ascertainments of the frequency of radiograms in 20 X-ray departments were used to determine per capita and collective doses, resp., in several age groups. Alltogether, the per capita dose of children in the GDR amounts to 30% of that of adults. Conclusions were drawn as to taking measures to further reduction of radiation exposure: (1) Technical measures, such as positioning of patients, shielding of organs, quality assurance; (2) elaboration of ...

Energy Technology Data Exchange (ETDEWEB)

A number of diagnostic X-ray units in Poland were subjected to analysis. The air kerma on X-ray tables was measured for the X-ray parameters used routinely during lumbo-sacral spine radiography of standard adult patient. Measurements of air kerma were performed using TLD made of lithium-fluoride. The doses received by patients in different X-ray departments can differ more than two orders of magnitude (from 0.42 mGy up to 72.11 mGy), for the same X-ray examination. The dose can be significantly reduced if fluorescent screens made from components of rare earth are used. (author). 10 refs, 1 fig., 2 tabs.

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Mixed-conducting Sr-Fe-Co oxides have potential applications in dense ceramic membranes for high-purity oxygen separation and/or methane conversion to produce syngas (CO + H{sub 2}), because of their combined high electronic/ionic conductivity and significant oxygen permeability. We studied the crystal structure and microstructure of the system in X-ray diffraction experiments and by using scanning electron microscopy, respectively. Thermogravimetric analysis was conducted on the SrFeCo{sub 0.5}O{sub x} sample in environments of various oxygen partial pressures (pO{sub 2}). Conductivity increased while weight decreased with increasing temperature. Activation energy decreased while conductivity increased with increasing pO{sub 2}. The pO{sub 2}-dependent conducting behavior of the SrFeCo{sub 0.5}O{sub x} system can be understood by considering the trivalent-to-divalent transition of transition-metal ions.

International Nuclear Information System (INIS)

Biaxially textured tungsten nanorods (A15 crystal structure) have been grown by oblique angle DC magnetron sputtering using a novel rotation mode called 'two-step rotation'. In this mode, the substrate is given a fast rotation through 1800 at 90 rpm and this is followed by a rest period of 30 s. These nanorods are vertically aligned and have a [100] texture normal to the substrate along with preferential in-plane texture as shown by x-ray pole figure analysis. In contrast, the tungsten nanorods obtained without substrate rotation are slanted at an angle of ?450 and have a [100] texture tilted 160 with respect to the substrate normal. The flux is incident from two diametrically opposite points on the sample at an oblique angle, averaging out the growth into vertical columns that retain the in-plane texture. Scanning electron microscopy shows that the tungsten nanorods have a mixture of {211} and {421} crystal habits; these planes are both ...

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Y{sub 2-x}Tb{sub x}SiO{sub 5} and Y{sub 2-x}Eu{sub x}SiO{sub 5} nanophosphors with seven different kinds of silicate sources were synthesized by sol-gel method. The structures have been investigated to be composed of nanometer-size grains of 30-60 nm through X-ray diffraction (XRD) and scanning electron microscopy (SEM) was used to compare the different morphology of patterns from seven different silicon sources. The photoluminescence of Y{sub 2-x}Tb{sub x}SiO{sub 5} was investigated as a function of silicate sources and the results revealed that these nanometer materials showed the characteristic emission {sup 5}D{sub 4} {yields} {sup 7}F{sub J} (J 6, 5, 4, 3) of Tb ions. The characteristic emission {sup 5}D{sub 0} {yields} {sup 7}F{sub J} (J = 1, 2, 4) of Eu ions was also found in the materials of Y{sub 2-x}Eu{sub x}SiO{sub 5}.

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Fine ceramic particles of zirconia toughened alumina (ZTA), titania toughened alumina (TTA), and zirconia-titania toughened alumina (ZTTA) have been synthesized by ultrasonic spray pyrolysis (USP) at various temperatures from starting salt solutions of various compositions aiming for the development of catalytic material. These particles were characterized for properties such as shape, size and size distribution, diffraction pattern, and chemical and phase composition of elements by scanning electron microscopy (SEM), particle size analyzer (PSA), x-ray diffraction (XRD), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Chemical compositions and sizes of ceramic composites have been controlled by the stoichiometry of salt solutions and the flow rate of spraying solutions. The optimum experimental conditions for the various composite particle synthesis have been proposed.

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The Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N{sub 2} gas was introduced to establish a treatment pressure of 8.0-8.4 x 10{sup -2} mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma-processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 {mu}m{sup 2} s{sup -1} at a plasma-processing time of 25 min was achieved. The formation of the hard phases TiN, Ti{sub 2}N, and Ti(N) in the Ti-6Al-4V surfaces are found to be the reason for the increased ...

Energy Technology Data Exchange (ETDEWEB)

Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti{sub 2}N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 {mu}m{sup 2}/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high concentration of active nitrogen species in the plasma atmosphere and the formed microcracks near ...

International Nuclear Information System (INIS)

An alloy of composition Ti-4.4 wt.% Ta-1.9 wt.% Nb is being developed as a structural material for corrosion applications, as titanium and its alloys possess excellent corrosion resistance in many oxidizing media. The primary physical metallurgy database for the Ti-4.4 wt.% Ta-1.9 wt.% Nb alloy is being presented for the first time. Determination of the #beta# transus, M_s temperature and classification of the alloy have been carried out, employing a variety of microscopy techniques, X-ray diffraction (XRD), micro-hardness and differential scanning calorimetry (DSC). The #beta# transition temperature or #beta# transus determined using different experimental techniques was found to agree very well with evaluations based on empirical calculations. Based on chemistry and observed room temperature microstructure, the alloy has been classified as an #alpha# + #beta# titanium alloy. The high temperature #beta# transforms to either #alpha#' or #alpha# ...

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In this study, SnO{sub 2} thin films have been grown using spray pyrolysis technique on glass substrates under a substrate temperature (T{sub s} = 440 {sup o}C). The precursors were methanol CH{sub 4}O and anhydrous tin tetrachloride. XRD analyses yielded strong (1 1 0)-(1 0 1)-(2 0 0) X-ray diffraction peaks which are characteristics to tetragonal crystals. Atomic Force Microscopy (AFM) analyses showed the existence of clusters with particular pyramidal shapes. The main part of this study concerns the optical measurements of transmittance T({lambda}) and reflectance R({lambda}) spectra inside 250-1800 nm domain. Conjoint optical and thermal properties were deduced using the Amlouk-Boubaker Opto-Thermal Expansivity {psi}{sub AB}. The obtained value: {psi}{sub AB} {approx} 23.4 m{sup 3} s{sup -1} helped situating the performance of the as-grown SnO{sub 2} compound among most known PV-T oxides like ZnO and TiO{sub 2}.

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Thin, lightweight, and flexible gas-diffusion electrodes (GDEs) based on freestanding entangled networks of single-walled carbon nanotubes (SWNTs) decorated with Ag nanoparticles (AgNPs) are tested as the air-breathing cathode in a zinc-air battery. The SWNT networks provide a highly porous surface for active oxygen absorption and diffusion. The high conductivity of SWNTs coupled with the catalytic activity of AgNPs for oxygen reduction leads to an improvement in the performance of the zinc-air cell. By modulating the pH value and the reaction time, different sizes of AgNPs are decorated uniformly on the SWNTs, as revealed by transmission electron microscopy and powder X-ray diffraction. AgNPs with sizes of 3-5 nm double the capacity and specific energy of a zinc-air battery as compared with bare SWNTs. The simplified, lightweight architecture shows significant advantages over conventional carbon-based GDEs in terms of weight, thickness and ...

International Nuclear Information System (INIS)

Technique, allowing to investigate straggling zone (full braking) from high-energy charged particles in detail, is described. Experimental results on investigation of efective structure, created in polycrystalline molybdenum (99.97%) within 29 MeV alpha-particles straggling zone for fluences from 3.8x10"1"9 up to 3.7x10"2"1 #alpha#/m"2 by methods of microhardness (H_#mu#, X-ray structural analysis (#DELTA#a/a) and transparent electron microscopy (TEM), are presented. It is determined, that for doses from 3.8x10"2"0 #alpha#/m"2 and higher, at #approx#6 MeV energy, molybdenum ''softening'' is observed, H_#mu# curve within straggling zone is well described by alloyage calculated profile. #DELTA#a/a measurements within straggling zone are well described by damage profile. TEM-investigations have shown the developed defective structure even within molybdenum ''softening'' range.

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The CaWO{sub 4}:Ln{sup 3+} SiO{sub 2} (Ln=Tb, Dy and Ho) nanoparticles were synthesized via a combustion process at 800 {sup o}C, using citric acid as chelating agent and fuel, ammonium nitrate as fuel, boric acid as flux material and silica as supports. The persistent phosphor nanoparticles were characterized by X-ray diffraction (XRD), reflectance UV-vis and fluorescence spectroscopy (PL) and transmission electron microscopy (TEM) techniques. XRD patterns indicated that crystalline calcium tungstate with scheelite structure was produced. The reflectance UV-vis spectra showed the broad absorption band of WO{sub 4}{sup 2-} groups and the PL spectra showed the WO{sub 4}{sup 2-} wide excitation band, broad emission band of WO{sub 4}{sup 2-} and characteristic emissions of Ln{sup 3+} ions. The average particle sizes were determined by TEM, which are about 50 nm.

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Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films were successfully prepared by the solution deposition using lithium acetate, aluminum nitrate, ammonium dihydrogen phosphate and titanium butoxide as starting materials. The structure, surface morphology, electrochemical window, and ionic conductivity of the films were studied by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance. The results showed that Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films annealed between 750 deg. C and 900 deg. C prepared by this method were well crystallized, homogenous and crack-free. The electrochemical window was beyond 2.4 V and the ionic conductivity was approximately 1.57x10{sup -5} S/cm at room temperature for the film annealed at 800 deg. C for 30 min.

International Nuclear Information System (INIS)

Here we describe the use of low energy plasma immersion with active screen as a convenient approach for polypropylene (PP) surface modification. Employing a stainless steel cathodic cage coated with carbon in order to prevent the sputtering of iron from the grid and its deposition onto the polymer sample, the physical chemical properties of PP surface could be effectively modified through the plasma-induced incorporation/formation of nitrogen- and oxygen-containing species. The areal densities of these elements depended on the plasma excitation source, as determined by Rutherford backscattering spectrometry (RBS). Newly formed C-O, C-N, and C=O/O=C-O/N-C=O bonds along with C-C linkages from the PP backbone were identified at the near surface region of the specimens by X-ray photoelectron spectroscopy (XPS). The insertion of such polar reactive functionalities was further confirmed by a substantial decrease in the water contact angle upon plasma treatment. Scanning ...

International Nuclear Information System (INIS)

A powder mixture of #alpha#-Si_3N_4, Al_2O_3, and TiO_2 was hot-pressed using different sintering cycles to search for an optimum in situ formed #beta#-O-sialon-TiN composite. The impulse excitation technique (IET), high-temperature X-ray diffraction (HTXRD), and scanning electron microscopy (SEM) were used to investigate the microstructure. Below the temperature of 1300 deg. C, the high-temperature internal friction (Q "-"1) decreases with the increase of sintering temperature, whereas the density of the material increases with the increase of sintering temperature. At a sintering temperature higher than 1850 deg. C, the ceramic could not be densified and O-sialon was not formed. Also, the mechanical properties of ceramics hot-pressed using different sintering cycles were assessed. The ceramic hot-pressed at 1700 deg. C for 10 min displays a combination of high hardness and good fracture toughness, due to an optimum combination of ...

International Nuclear Information System (INIS)

The occurrence of stable decagonal quasicrystalline phase in Al-Co-Ni and Al-Cu-Co alloys through conventional solidification is well established. Earlier, we have studied the effect of Cu substitution in place of Co in the Al_7_0Co_1_5Ni_1_5 alloy. Here we report the structural/micro-structural changes with substitution of Cu for Ni in rapidly solidified Al-Co-Ni alloys. The melt spun ribbons have been characterized using X-ray diffractometry, scanning and transmission electron microscopy. With an increase in Cu content in the melt spun Al_7_0Co_1_5Cu _xNi_1_5_-_x (x = 0-15 at.%) alloys, the relative amount of the decagonal phase decreased up to 10 at.% of Cu. At this composition, the quaternary alloy showed the co-existence of decagonal quasicrystal and superstructure of #tau#_3 vacancy ordered crystalline phases. The decagonal phase containing Cu showed more disordering than Al-Co-Ni alloys. The implication of the structural and ...

Energy Technology Data Exchange (ETDEWEB)

A method of kinetic analysis applicable to non-isothermal oxidation processes of ceramic nanocomposites is presented using Ti-Si-C-N powder as the substrate. The nanoparticle size and phase composition were determined using high-resolution transmission electron microscopy and X-ray diffraction (XRD). Thermogravimetric measurements were carried out for powder samples in dry air in the temperature range 298-1770 K. The following heating rates were applied: 3, 5, 10, 20 K min{sup -1}. Mass spectrometry was used to analyze gaseous oxidation products and solid products were identified by the XRD technique. The Coats-Redfern equation was applied for the kinetic analysis. For each stage of the oxidation kinetic models, the best accuracy was achieved using a series of criteria, and then the A and E parameters of the Arrhenius equations were estimated. Both linear regression and artificial neural networks were applied in testing kinetic models.

International Nuclear Information System (INIS)

In the present study, Fe_4_1Co_4_1 B_1_0Zr_7Cu_1 alloy has been investigated in order to evaluate its thermal stability and structure after heat treatment, as well as the impact of heat treatment on magnetic properties. X-ray diffractometry, differential scanning calorimetry, chemical composition microanalysis, transmission electron microscopy, and magnetic hysteresis loop measurement techniques were employed. The crystallization temperature of the as-quenched alloy is 490"oC (continuous heating at 5 "oC/min). The melt spun ribbon having 27 #mu#m in thickness was annealed for 1 hour at temperatures from 400 to 700 "oC. The alloy after treatment at about 550"oC underwent primary crystallization, with the average size of crystals under 20 nm. This specimen shows the coercive field of 38 A/m, as compared to about 160 A/m reported for a similar alloy (Fe_4_4Co_4_4B_4Zr_7Cu_1) with a similar structure, annealed at 600"oC. (author)

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Piezoelectric ceramics for acoustic applications have been prepared by mixing the piezoelectric phase Pb{sub 1-1.5x}La{sub x}{open_square}{sub x/2}(Ti{sub 1-y}Zr{sub y})O{sub 3} (PLZT) with variable fractions of Al{sub 2}O{sub 3}. The samples are in form of pellets and polarized at high temperature. After thermal treatment, X-ray diffraction and scanning electron microscopy have been used to determine the phase and morphological modifications. The morphotropic PLZT initial phase disproportionates into modified PLZT and ZrO{sub 2} phases. Using electrical impedance spectroscopy, the resonance frequencies of the composite system have been determined and analyzed. As the Al{sub 2}O{sub 3} volume fractions increase, the resonance frequency and the amplitude of the electrical response both decrease. An interpretation of the role of Al{sub 2}O{sub 3} additions is proposed in terms of phase and microstructure modifications. Using LRC electrical ...

International Nuclear Information System (INIS)

Iron oxide films have been deposited on Si(100) substrates by chemical vapour deposition (CVD) of iron(III) tert-butoxide ([Fe(O "tBu)_3]_2) in the temperature range 350-450 deg. C. The precursor flux and substrate temperature were varied to control the phase composition, average grain size and film thickness. The nature of substrate and deposition temperature markedly influence the morphology and iron-oxygen stoichiometry in the CVD deposits. Phase transformations in iron oxide films were achieved through precise local and periodic heating of the films by interfering laser beams. The interaction of iron oxide films with short laser pulses (Nd:YAG, 355 nm) induced partial transformation of hematite (#alpha#-Fe_2O_3) to magnetite (Fe_3O_4) or magnetite to wuestite (Fe_1_-_xO), respectively. The phase characterization and morphology of the hematite and magnetite films were investigated before and after laser irradiation by X-ray diffractometry, high resolution ...

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When a metallic alloy is quenched into a miscibility gap, a mixture of two phases develops, whose domain structure then coarsens because of the interfacial energy between the two phases. This spatial arrangement of the domains and the rate at which they evolve may be strongly influenced by elastic interactions. In a recent paper, the authors described a method for simulating the effect of anisotropic elastic interactions in a two-dimensional Ising model of a cubic alloy, using Kawasaki dynamics with the elastic interactions represented by a long-range two-body interaction potential. Here they present the results of such simulations at various temperatures, alloy compositions and misfits (by misfit they mean the difference in size between the two kinds of atom), exhibiting snapshots both of the microscopic configurations (corresponding to experimental measurements using transmission electron microscopy) and of their squared Fourier transforms (corresponding to ...

CERN Document Server

Non-evaporable thin film getters of various compositions have been produced by sputtering. Among about 20 materials which have been studied, the lowest activation temperature (about 180 degree C) has been displayed by a Ti-Zr-V coating obtained from a cathode made of intertwisted elemental wires. In order to optimize the vacuum properties of this film various production parameters, including the substrate temperature during coating, have been varied. The films have been characterized by pumping speed measurement, secondary electron microscopy, and X-ray diffraction. It has been found that the substrate coating temperature affects significantly the activation temperature, the pumping speed and the gas surface capacity. The highest pumping speed values, obtained for substrate coating temperatures of 250 degree C and 300 degree C, are clearly correlated with the increased surface roughness and porosity of the Ti-Zr-V film.

British Library Electronic Table of Contents (United Kingdom)

A series of spinel Li4Ti5O12 samples were synthesized via a composite molten-salt method (CMSM) using the mixtures of LiCl and KCl with different L values (L is defined as the molar ratio of LiCl:KCl) as the reaction media. It is found that the melting point of the composite molten salt can effectively influence the formation of particles, and leads to different electrochemical performances of the as-prepare Li4Ti5O12. The investigations of X-ray diffraction (XRD), particle size distribution (PSD), Brunauer-Emmet-Teller (BET) surface area, and scanning electron microscopy (SEM) indicate that the as-prepared Li4Ti5O12 with L=1.5 is a pure phase, and has uniform homogeneous octahedral shape particles, rather narrow PSD, and high BET surface area. Electrochemical tests show that the optimized...

International Nuclear Information System (INIS)

A series of experiments have been conducted on AISI 5140 low alloy steel using a hollow cathode discharge-assisted plasma nitriding apparatus with the aim of elucidating the role of substrate bias voltages in plasma nitriding process. For comparison, some samples were nitrided with applied substrate bias (-50 V) while other samples were nitrided at floating potential. Treatments were carried out in NH_3 atmosphere of 150 Pa at temperatures ranging from 450 "oC to 550 "oC for 2 h, 4 h, and 6 h. The nitrided samples were characterized by optical microscopy, X-ray diffraction and micro-hardness measurement. The corrosion behaviors were evaluated using anodic polarization tests in 3.5% NaCl solution. The results showed that the microstructure and phase constituents of the nitride layers were strongly influenced by the bias voltages. It was also demonstrated that the better corrosion resistance with a thicker nitrided layer was obtained on the ...

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Polycrystalline silicon films have been grown from Si{sub 2}H{sub 6} by low-pressure chemical vapour deposition at 800 K and in situ laser annealing (LA) on amorphous silicon seed layers deposited on a metallic Ti/Pd/Ag multilayer. The crystalline volume fraction in the seed layer was controlled by thermal annealing. According to the metal-induced crystallization effect, the presence of the metal induces a lower-temperature crystallization of silicon in the seed layers. X-ray diffraction and scanning electron microscopy data show that the formation of palladium silicides in the seed layer drives the growth of wire-like columns which are found to change morphology depending on the seed layer microstructure and LA parameters. It is suggested that superficial palladium was found to affect also the growth rate by enhancing the Si{sub 2}H{sub 6} dissociation.

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Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed after oxy-fluorination, whereby the polar component was strongly ...

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The effects of the plasma nitriding with the formation of compound nitride and diffusion zones and of the boronising with the different ion doses on hydrogen distribution and hydrogen induced deterioration of a surface layer were examined in the case of Armco iron. Electrochemical studies of hydrogen permeation rate, hydrogen vacuum extraction measurements, optical and scanning microscopy, X-ray diffraction and elastic recoil detection analysis (ERDA) were used. Accumulation of entering hydrogen within the various constituent zones of the modified layer inhibits the hydrogen transport into the metal and thus, decreases the mean hydrogen content in the deeper zones and in the core. Hydrogen accumulation within the compact nitride zone causes the expansion of the nitride lattice, nitride phase transformation and deterioration. The ion boronising enhances the hydrogen effects in the plasma nitrided layers. Therefore, modification of the surface ...

International Nuclear Information System (INIS)

The formation and growth of silicon-nanoparticles from silane in a microwave reactor was investigated. Experiments were performed for the following conditions: precursor concentration 380-2530 ppm, pressures of 20-30 mbar, microwave powers 120-300 W. The formed particles were examined in-situ with a particle mass spectrometer. Additionally, particles were collected on grids and analyzed by transmission electron microscopy, X-ray diffraction, and by determining the specific surface area by BET. The particle size was found to be in the range of 5-8 nm in diameter. A simple model was used to simulate the particle formation processes taking place inside the reactor. The microwave energy coupled into the reactor flow was treated as a spatially distributed energy source resulting in a local temperature increase. The particles were assumed to have a monodisperse size distribution. To allow an approximation of their shape they were characterized by ...

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Alkaline fuel cells (AFCs) provide a less corrosive environment and can provide higher electrode reaction kinetics than proton exchange membrane fuel cells (PEMFCs). The alkaline media also allows for the replacement of platinum (Pt) based electrocatalysts with non-Pt electrocatalysts. Studies have shown that palladium (Pd) and silver (Ag) form a homogenous solid solution with a face-centred cubic structure within a large range of temperatures. This study described the results of an oxygen reduction reaction (ORR) on lead-silver (Pd-Ag) alloy electrodes in alkaline media. The reaction was compared with Pd and Ag electrodes. The alloys were synthesized as thin films using a sequential electroless deposition of Pd and Ag on stainless steel discs followed by an annealing procedure in an Ar stream. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize catalyst structure, ...

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The sequence of nitride formation during the early stages of plasma nitriding of pure iron was studied by optical microscopy, SEM, TEM and x-ray diffraction. Plasma nitriding at {approximately}490 C in a 25 vol.%H{sub 2} + 75 vol.%N{sub 2} mixture starts with the formation of {gamma}{prime}-Fe{sub 4}N after 40s. Once {gamma}{prime} nucleates, it mainly spreads laterally due to diffusion shortcuts in the discontinuous surface nitride layer. Before {gamma}{prime} is continuous on the surface, {epsilon} nucleates on top of it shortly after 40S. Epsilon is then observed to grow, both inwardly and laterally along with {gamma}{prime}. A compact {gamma}{prime}/{epsilon} bilayer forms on the surface at around 100s. The kinetics of nucleation, growth and compactation of the nitrides observed in the present work was significantly more rapid than in any of the nitriding process reported in the literature, including plasma nitriding. The acceleration of ...

British Library Electronic Table of Contents (United Kingdom)

Abstract We prepared BiOCl1-xBrx (x=0-1) solid solutions and characterized their structures, morphologies, and photocatalytic properties by X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, Raman spectroscopy, photocurrent and photocatalytic activity measurements and also by density functional theory calculations for BiOCl, BiOBr, BiOCl0.5Br0.5. Under visible-light irradiation BiOCl1-xBrx exhibits a stronger photocatalytic activity than do BiOCl and BiOBr, with the activity reaching the maximum at x=0.5 and decreasing gradually as x is increased toward 1 or decreased toward 0. This trend is closely mimicked by the photogenerated current of BiOCl1-xBrx, indicating that the enhanced photocatalytic activity of BiOCl1-xBrx with respect to those of BiOCl and BiO...

International Nuclear Information System (INIS)

In this study, perovskite type oxide YAlO_3 has been doped with different amounts of the divalent cation Ca to synthesize Y_1_-_xCa_xAlO_3_-_#delta# (x = 0-0.21) compositions. The effect of dopant concentration on the crystal structure and electrical properties of YAlO_3 synthesized by citrate gel route has been investigated. The phase purity of the samples has been carried out using X-ray diffraction. The microstructural evaluation of the samples has been conducted by scanning electron microscopy and energy dispersive spectrum analysis. Thermal analysis has been conducted to monitor the decomposition of the intermediate products. The electrical conductivity studies have been performed using a.c. impedance spectroscopy as a function of temperature in the range 200-800 "oC in air. The Y_0_._9_4Ca_0_._0_6AlO_3_-_#delta# composition exhibits a total conductivity of 2.5 mS/cm at 800 "oC.

British Library Electronic Table of Contents (United Kingdom)

Cobalt supported on Beta zeolite catalysts were prepared by impregnation of metal salts in aqueous solution and were tested for the Fischer Tropsch reaction. The support consisted of a Beta zeolite composed by crystallites of nanometric dimensions and a SiO2/Al2O3 molar ratio of about 50. This support was impregnated with Co(NO3)2 aqueous solution using different metal loads of 7.5, 10, 15 and 20wt% Co. These materials were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), N2 adsorption (BET), thermal programmed reduction (TPR) and FTIR of adsorbed pyridine (i.e., surface acid sites distribution). All the catalysts showed a significant catalytic activity for the F-T reaction from synthesis gas (CO+2H2), in a continuous fixed bed reactor sys...

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We report a templated-synthetic approach based on apoferritin to prepare radionuclide nanoparticle (NP) conjugates. Non-radioactive yttrium (89Y) was used as model target and surrogate for radioyttrium (90Y) to prepare the nanoparticle conjugate. The center cavity and multiple channel structure of apoferritin offer a fast and facile method to precipitate yttrium phosphate by diffusing yttrium and phosphate ions into the cavity of apofrritin, resulting a core-shell nanocomposite. The yttrium phosphate/apoferritin nanoparticle was functionalized with biotin for further application. The synthesized nanoparticle was characterized by transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). We found that the resulting nanoparticles were uniform in size, with a diameter of around 8 nm. We tested the pre-targeting capability of the biotin-modified yttrium phosphate/apoferritin nanoparticle (yttrium phosphate/apoferritin ...

Science.gov (United States)

The interaction of the globular protein lysozyme with silica nanoparticles of diameter 20 nm was studied in a pH range between the isoelectric points (IEPs) of silica and the protein (pH 3-11). The adsorption affinity and capacity of lysozyme on the silica particles is increasing progressively with pH, and the adsorbed protein induces bridging aggregation of the silica particles. Structural properties of the aggregates were studied as a function of pH at a fixed protein-to-silica concentration ratio which corresponds to a surface concentration of protein well below a complete monolayer in the complete-binding regime at pH > 6. Sedimentation studies indicate the presence of compact aggregates at pH 4-6 and a loose flocculated network at pH 7-9, followed by a sharp decrease of aggregate size near the IEP of lysozyme. The structure of the bridged silica aggregates was studied by cryo-transmission electron microscopy (cryo-TEM) and small-angle ...

International Nuclear Information System (INIS)

A tri-functional polyhedral oligomeric silsesquioxane (POSS) based silane precursor R_xR_yR_z(SiO_3_/_2)_n (x + y + z = n = 6, 8, 10, ...) bearing 3-(N-(3-triethoxysilylpropyl)ureido)propyl, isooctyl and perfluoropropyl groups was synthesized and investigated as corrosion protective coating for AA 2024 alloy. Infrared reflection-absorption (IR RA) combined with X-ray photoelectron spectroscopy and atomic force microscopy provided information about partial self-assembling of coatings having a fluorine enriched upper layer with a low surface energy (#gamma#"t"o"t = 12.37 mN/m). The structural changes that accompanied corrosion produced under chronocoulometrical conditions were assessed from ex-situ IR RA spectra. A new band at 1690-1700 cm"-"1 appeared above the corrosion potential, and was assigned to the formation of amidonium ions and consequent relaxation of urea-urea associations.

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X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) have been conducted on a new fuel cell electrocatalytic material based on a highly porous carbonized polyacrylonitrile (PAN) microcellular foam with very low platinum loading ({approximately}13 to 23 {micro}g/cm{sup 2}). TEM images of this material clearly show the existence of nanometer size platinum particles which are homogeneously distributed in the highly porous carbonized PAN matrix. An XPS study of Pt-loaded PAN indicates that C 1s, O 1s, and N 1s peaks shift to lower binding energies, compared to virgin PAN. It was concluded that special metal-support interaction exists, through the formation of a charge-transfer complex between platinum and pyridine-type nitrogen atoms of PAN support. This interaction leads to the enhancement of the catalytic activity, and the improvement of the long-time stability of this electrocatalyst.

International Nuclear Information System (INIS)

The effect of anode length and operating gas pressure on the x-ray emission from a nitrogen-filling modified plasma focus device has been investigated. The time-resolved investigation of x ray was carried out by using a five-channel photodiode x-ray spectrometer. The maximum x-ray yield is seen to increase with the increase in the anode length from 110 to 125 mm. Further increase in the anode length to 130 mm causes the x-ray yields to decrease. The highest x-ray yield of 4.5 J into 4#pi# sr was found for 125 mm anode length, which is 0.2% of the input energy. The average x-ray photon energy was estimated by using half-value thickness method and found to be 8.4 keV. The electron temperature of the plasma was estimated to be around 3 keV by x-ray intensity ratio method. The space-resolved ...

Science.gov (United States)

Silver iron oxide nanoparticles of fairly small size (average diameter approximately 1 nm) with narrow size distribution have been synthesized by the interaction of colloidal beta- Fe2O3 and silver nanoparticles. The surface morphology and size of these particles have been analyzed by using atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Their structural analysis has been carried out by employing x-ray diffraction (XRD), selected-area electron diffraction (SAED), optical and infrared (IR) spectroscopic techniques. The ageing of these particles exhibits the formation of self-assembly, possibly involving weak supramolecular interactions between Ag(I)O4 and Fe(III)O4 species. These particles display the onset of absorption in the near-infrared region and have higher absorption coefficient in the visible range compared to that of ...

International Nuclear Information System (INIS)

In this work, ZnO thin films have been grown on glass substrates by using a solution of propanol (C3H8O), water (H2O) and zinc acetate (Zn(CH3CO2)2) in acidified medium (pH 5). The obtained films were n doped with ytterbium (Yb) at the rates of 100, 200 and 300 ppm. The structural features of the doped films were investigated using XRD, atomic force microscopy and scanning electronic microscopy techniques. XRD analysis shows a strong (0 0 2) X-ray diffraction line for increasing Yb-doping amounts. This c-axis preferential orientation of ZnO crystallites is naturally required to use this oxide as transparent conductor in optoelectronic applications. Atomic force microscopy (AFM) analysis shows an enhancement in the surface roughness of the doped ZnO:Yb thin films. Optical measurements were performed in 300-1800 nm domain via transmittance T(?) and reflectance R(?) spectra. Conjoint optical and thermal ...

Science.gov (United States)

... Accession Number : ADA535309. Title : X-Ray Phase Imaging for Breast Cancer Detection. Descriptive Note : Annual rept. 1 Sep 2009-31 Aug 2010 ...

UK PubMed Central (United Kingdom)

Microplanar beam radiation therapy has been proposed to treat brain tumors by using a series of rapid exposures to an array of parallel x-ray beams, each beam having uniform microscopic thickness and...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Radionuclide X-ray fluorescence analysis was used for the determination of iron, calcium, potassium, copper, manganese and zinc in waste water from the production process of citric acid.

International Nuclear Information System (INIS)

Exact anatomic knowledge about the location of the gonads and the application of corresponding measures of radiation protection are the preconditions for an efficient reduction of the danger of a possible genetic damage as a result of radiation exposition during X-ray examination of the hip joint of newborns. (VJ).

International Nuclear Information System (INIS)

The optoelectronic compounds of GaAs and ZnSe are difficult to analyze by PIXE (particle-induced X-ray emission) due to the strong absorption of the As and Se K_#alpha# X-rays. As part of a program to investigate optoelectronic materials using ion beam techniques, we have explored the possibility of using the high sensitivity of PIXE to check these materials for stoichiometry and dopant concentrations. The K_#alpha# X-ray intensity ratios of Ga to As and Zn to Se have been investigated using H beams of 0.5 to 2.5 MeV and He beams of 1.0 to 2.5 MeV. The variation in the X-ray intensity ratio with beam energy and target thickness is modelled in terms of the cross section for X-ray production and the absorption coefficients of the X-rays in the target. The results of this model show the experimental conditions that must be satisfied in order that the ...

UK PubMed Central (United Kingdom)

An examination of the noise of polycrystalline silicon thin film transistors, in the context of flat panel x-ray imager development, is reported. The study was conducted in the spirit of exploring...Full Text Available

UK PubMed Central (United Kingdom)

In this paper, we report a method of precise in situ x-ray scattering measurements on protein solutions using small stationary sample cells. Although reduction in the radiation damage...Full Text Available

International Nuclear Information System (INIS)

Differential phase-contrast X-ray imaging has been performed in a Talbot-Lau configuration, where a multiline X-ray source was used instead of a combination of a hard-X-ray multiple slit and a normal focus X-ray generator. When the multiple slit is used, a high aspect ratio structure is needed and slit width should be below 10 ?m for its function. The fabrication and use of such a multislit can be omitted using the presented configuration. The multiline X-ray source was developed by making grooves on a tungsten rotating anode, which was irradiated by an electron beam to generate X-rays. An array of 10?m line sources with a pitch of 30?m was formed and combined with a 4.5 ?m pitch phase grating and a 5.3 ?m pitch amplitude grating to generate differential phase contrast. With a total exposure time of 40 s, a differential phase image depicting cartilages was ...

International Nuclear Information System (INIS)

A photon-induced x-ray fluorescence method allowing the simultaneous determination of iron, copper, zinc, bromine and rubidium in human blood and blood plasma samples is described. The method is reliable and has a good sensitivity for a wide range of elements. (author).

International Nuclear Information System (INIS)

K_#beta#/ K_#alpha# x-ray intensity ratio of chromium were measured in different chromium compounds. The results show the variation of the intensity ratio as a function of the chemical environment around the metal ion. (author)

CERN Document Server

We present the X-ray properties of a sample of 17 radio sources observed with the Chandra X-ray Observatory as part of a project aimed at studying the X-ray emission from their radio jets. In this paper, we concentrate on the X-ray properties of the unresolved cores. The sample includes 16 quasars (11 core-dominated and 5 lobe-dominated) in the redshift range z=0.30--1.96, and one low-power radio-galaxy at z=0.064. No diffuse X-ray emission is present around the cores of the quasars, except for the nearby low-power galaxy that has diffuse emission on a scale and with a luminosity consistent with other FRIs. No high-amplitude, short-term variability is detected within the relatively short Chandra exposures. However, 1510-089 shows low-amplitude flux changes with a timescale of $\\sim$25 minutes. The X-ray spectra of the quasar cores are generally well described ...

UK PubMed Central (United Kingdom)

Previous studies have shown that iterative in-line x-ray phase retrieval algorithms may have higher precision than direct retrieval algorithms. This communication compares three iterative phase...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Abstract not provided

International Nuclear Information System (INIS)

Czech May 1979. p. 32-33. Czechoslovakia Benada, J. Spacek, B. Ustav

International Nuclear Information System (INIS)

... Union (INTAS), Brussels (Belgium) Science and Technology Center in Unkraine,

International Nuclear Information System (INIS)

An interferometric technique for hard X-rays is presented. It is based on two transmission gratings and a phase-stepping technique, and it provides separate radiographs of the phase and absorption profiles of bulk samples. Tomographic reconstruction yields quantitative three-dimensional maps of the X-ray refractive index and of the attenuation coefficient, with a spatial resolution down to a few microns. The method is mechanically robust, it requires little monochromaticity, and can be scaled up to large fields of view. These are important prerequisites for use with laboratory X-ray sources. Numerous applications ranging from wave front sensing to medical radiography are presently under investigation.

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

The ELXS concept is a novel, portable, micro-instrument targeted for the detection of mineralogic

International Nuclear Information System (INIS)

High (spatial) resolution imaging detectors for X-ray astronomy were developed. Several prototype detectors built and their feasibility and baseline performance were assessed. Two of these detector types are proposed for investigations on the advanced X-ray astrophysics facility (AXAF). The readiness of a new X-ray imaging system, the charge coupled device (CCD) imaging specctrometer is outlined, and state of the art performance parameters for microchannel plate (MCP) and CCD detectors are measured. Laboratory facilities and procedures for coating MCP are developed general high resolution imagery systems are analyzed.

Energy Technology Data Exchange (ETDEWEB)

Chemical effects of L X-ray intensity ratios in niobium and molybdenum compounds were studied by electron and proton bombardments. L{sub {gamma}1} X-rays which involve transition of 4d electrons of the valence shell were found to be sensitive to the chemical environment. The L{sub {gamma}1}/L{sub {beta}1} X-ray intensity ratio increased with an increase of the 4d electron occupation of niobium or molybdenum in niobium or molybdenum compounds, showing that the chemical effects can be ascribed to the 4d electron behavior of the metallic atom in its compounds. (orig.).

Energy Technology Data Exchange (ETDEWEB)

This case report evaluates X-ray findings in patients with miliary accumulation of mercury observed after parenteral application of metallic mercury in a suizide attempt. There are certain discrepancies between clinical symptoms and the X-ray findings. A clear demonstration of mercury in coronary blood vessels is possible by fluoroscopy.

International Nuclear Information System (INIS)

The physical foundations and methodology are described of radionuclide X-ray fluorescence analysis. The sources are listed of air, water and soil pollution, and the transfer of impurities into biological materials is described. A detailed description is presented of the sampling of air, soil and biological materials and their preparation for analysis. Greatest attention is devoted to radionuclide X-ray fluorescence analysis of the components of the environment. (ES).

International Nuclear Information System (INIS)

Applications of X-ray fluorescence analysis in coal mining and geology are briefly described based on results published in Czechoslovakia as well as abroad over the past 3 years. Particular attention is paid to the rapid determination of the ash content of coal using portable radionuclide X-ray fluorescence analyzers that are being developed in Czechoslovakia. (author).

International Nuclear Information System (INIS)

Airborne lead particulates collected on a membrane filter were determined by the nondestructive X-ray fluorescence method. The gamma/X radionuclide source "2"4"1Am/Ag and a scintillation detector with a NaI/Tl crystal were used for the excitation and detection, respectively, of L X-rays of Pb. One can say, with reference to the obtained results, that the sensitivity and accuracy of the measurement is more than adequate for monitoring the Pb level in air. (author).

International Nuclear Information System (INIS)

At the RIKEN-RAL Muon Facility, ?- to ? sticking K? X-rays were observed for the first time taking advantage of the pulsed beam structure. The precision of the present measurements was insufficient to distinguish between theoretical models, however the observed K?/K? X-ray intensity ratio tends to be smaller than most of these theoretical predictions.

Energy Technology Data Exchange (ETDEWEB)

In this article, the author presents the main technological solutions, available or in development, on X-ray detectors in order to obtain a digital image in biomedical radiography or in industrial radiography: linear x-ray detectors and bidimensional x-ray detectors (memory radioluminescent screens, matrix plan detectors).

International Nuclear Information System (INIS)

Determination of Mn, Fe, Ni, Cu, Zn, and Pb in human soft tissues by radionuclide X-ray fluorescence analysis (using "2"3"8Pu and "1"0"9Cd sources) is described. The results of multielement XRS analysis of selected human tissues are tabulated. They are in good agreement with the literature data. It is concluded that X-ray fluorescence technique is a suitable method for trace element determination. (author).

Energy Technology Data Exchange (ETDEWEB)

A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

Energy Technology Data Exchange (ETDEWEB)

An x-ray diffraction technique for determining thin-film thickness is presented which should prove to be a valuable alternative to the array of spectroscopies (Rutherford backscattering spectrometry, Auger electron spectroscopy, etc.) currently favored for these measurements. Some of the virtues of this x-ray diffraction approach are its nondestructive nature, fast data acquisition rate (enabling in situ observations), thickness resolution better than 5 nm, and conventional equipment requirements. Results are shown for Pd/sub 2/Si thin films grown during isothermal annealing of Pd coatings (100 nm) on Si at 200 /sup 0/C for various amounts of time. A comparison of these x-ray measurements with Rutherford backscattering spectrometry data taken from the same specimens is used to demonstrate the validity of the x-ray technique.

Energy Technology Data Exchange (ETDEWEB)

The {ital L}{sub 2}-{ital L}{sub 3} Coster-Kronig transition probability ({ital f}{sub 23}) in Tm was measured by multiparameter {ital K} versus {ital L} x-ray coincidence techniques. The Tm x rays were obtained from a radioactive source of {sup 169}Yb and were detected with cooled germanium and silicon detectors of high-energy resolution. Corrections were applied for the contribution of {ital K}{alpha}{sub 1} x rays to the {ital K}{alpha}{sub 2} x-ray peak and for the contribution of unresolved {ital L}{eta} x rays to the {ital L}{alpha}{sub 1,2} x-ray peak. The contribution of {ital K}{alpha}{sub 1} x rays to the {ital K}{alpha}{sub 2} x-ray peak was determined solely from the results of the coincidence measurements using a method of ...

Energy Technology Data Exchange (ETDEWEB)

The interaction of intense, sub-picosecond laser pulses with solid targets produces intense picosecond x-ray pulses. With focused laser pulses of several 10 {sup 18} W/cm{sup 2}, He-like and H-like line radiation from targets such as aluminum and silicon has been produced. The energy conversion efficiency from the laser pulse energy to the 1--2 keV line x-rays is nearly one percent. The duration of the line x-ray radiation is of the order of ten picoseconds, although this may be an upper estimate because of the temporal resolution of the x-ray streak camera. The spatial extent of the x-ray source region is only slightly larger than the laser focal spot, or about 10 {mu}m in diameter. With these characteristics, such x-ray sources emit an intensity of nearly 10{sup 14} W/cm{sup 2}. Experiments and modeling which led to the above conclusions will be discussed.

Energy Technology Data Exchange (ETDEWEB)

A portable X-ray image system is described comprising: (a) a base assembly including panels and hinges joining the panels together along edges, and compression stops for biasing the hinges to compensate for the weight of payload when mounted on the base assembly, the compression stops being located for interaction with the hinges for biasing the panels to exhibit upward bowing when laid upon a flat surface prior to loading, and to provide resiliency for facilitating the base assembly assuming a substantially flat configuration when a predetermined payload is placed upon the base assembly; (b) an X-ray member; (c) apparatus for detachably mounting a table member to the base assembly to hold the table member at a location above the base; (d) an X-ray source; (e) means for sensing X-rays to form an image; (f) means for mounting the X-ray source and the X-ray ...

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The peak flux relationship between hard X-rays and microwaves from solar flares is studied using about 400 events simultaneously recorded with the hard X-ray burst spectrometer on the SMM satellite and the Nobeyama 17 GHz radiometer. The data indicate that the hard X-ray and microwave peak fluxes correlate best for X-ray energies of less than about 80 keV for impulsive flares and greater than about 360 keV for extended flares. By postulating that electrons responsible for microwave emission at 17 GHz are those emitting hard X-rays at these photon energies, it is concluded that: (1) in impulsive flares, microwaves at about 20 GHz are emitted mainly by electrons of less than about 200 keV from a layer through which the electrons stream down into the thick-target hard X-ray source; and (2) in extended flares, microwaves are emitted mainly by MeV electrons trapped ...

International Nuclear Information System (INIS)

We report the detection of X-ray pulsations with a period of ?315.87 ms from the 2009 XMM-Newton observation for the radio-quiet ?-ray pulsar, LAT PSR J0007+7303, centered in the supernova remnant CTA 1. The detected pulsed period is consistent with the ?-ray periodicity at the same epoch found with the Fermi Gamma-ray Space Telescope. The broader sinusoidal structure in the folded light curve of the X-ray emission is dissimilar to that of the ?-ray emission, and the phase of the peak is about 0.5 shifting from the peak in the ?-ray bands, indicating that the main component of the X-rays originates from different sites of the pulsar. We conclude that the main component of the X-ray pulsation is contributed by the thermal emission from the neutron star. Although with a significantly different characteristic age, PSR J0007+7303 is similar to Geminga in emission properties of X-rays ...

CERN Document Server

Recent X-ray and radio observations have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we report the detailed analysis of X-ray and infrared observations of the transient and its surroundings. Chandra bservations detect the source at a flux of F_X = 2e-12 erg cm^-2 s^-1 (2-8 keV). After accounting for absorption both in the interstellar medium and in material local to the source, the implied luminosity of the source is only L_X = 4e34 erg/s (2-8 keV; D=8 kpc). However, the diffuse X-ray emission near the source also brightened by a factor of 2. The enhanced diffuse X-ray emission lies on top of a known ridge of dust and ionized gas that is visible infrared images. We interpret the X-ray emission as scattered flux from the outburst, and determine that the peak ...