International Nuclear Information System (INIS)

Large, complex, high purity ceramic shapes are required by a variety of emerging technologies for their electrical insulation and high temperature strength properties coupled with their refractoriness and purity. Ceramic sealant bonding, using crystalline and vitreous sealant materials, has recently shown significant potential for joining technical ceramics to form the required shapes. Materials and techniques for joining technical ceramics including alumina, magnesia, zirconia and thoria are discussed. (orig.).

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

In this study nanocrystalline powders of yttria-stabilized zirconia (ZrO_2-8Y_2O_3) have been synthesized through 'polymerized complex method'. Zirconium chloride, yttrium nitrate, citric acid and ethylene glycol were polymerized at 80 "oC to produce a gel-like mass in which metallic ions were uniformly distributed. During the thermal treatment of dried gel, nanocrystalline powder was formed at 450 "oC and 650 "oC for 2 h. Thermal reactions and crystalline phase formation of the dried gel were investigated through thermal analysis and X-ray diffraction analysis, respectively. The results of thermal analysis and XRD showed the formation of nanocrystalline powder at less than 600 "oC. Chemical bonding of the dried gel was investigated by Fourier transform infrared spectroscopy analysis. Morphology of powder calcined at 650 "oC was analyzed by scanning electron microscope. Yttria-stabilized zirconia powders with the mean ...

International Nuclear Information System (INIS)

New data about the structure of high-temperature resistant metalloceramic plasma sprayed coatings in micro and nano areas are presented. Application of the new instrumental methods: transmission electron microscopy combined with selected area electron diffraction mode is possible to obtain these data. The first layer in Ni based metallic bond coat shows nanocrystalline structure. External ceramic layer based on stabilised ZrO_2 is polycrystalline and contains both cubic and tetragonal crystalline phases. Local inhomogeneities in coatings phase composition are determined. (author)

CERN Document Server

Simulation approaches for nano-scale semiconductor devices

Energy Technology Data Exchange (ETDEWEB)

One of the most challenging topics in the area of organic electronic devices is the growth of transparent electrodes onto flexible polymeric substrates that will be characterized by enhanced conductivity in combination with high optical transparency. An essential aspect for these materials is their synthesis and/or microstructure which define the transparency, the stability and the interfacial chemistry which in turn determine the performance and stability of the organic electronic devices, such as organic light emitting diodes, organic photovoltaics, etc. In this work, we will discuss the latest advances in the growth of organic (e.g. PEDOT:PSS) and inorganic (e.g. zinc oxide-ZnO, indium tin oxide-ITO) conductive materials and their deposition onto flexible polymeric substrates. We will compare the optical, structural, nano-mechanical and nano-topographical properties of the inorganic and organic materials and we investigate the effect of ...

Energy Technology Data Exchange (ETDEWEB)

Our institute has been investigating laser-produced tin, lithium and xenon plasma for extreme ultraviolet (EUV) light source of EUV lithography system, and found the highest conversion efficiency of 3% at 13.5 nm in 2% bandwidth. In the present paper, we introduce fabrication methods of density-controlled tin targets to generate relatively monochromatic EUV, and higher conversion efficiency than bulk tin. The first method is the nano-template method, where liquid tin solution was immersed into a polymer film with monodispersed size nano-particle. The density can be controlled by tin concentration of the solution. The target can be classified into mass-limited target. We have shown a tendency of monochromatic EUV emission around 13.5 nm with decreasing of tin density. The intensity was higher than tin foil with bulk density. The tendency has a merit to mitigate heat effect of the first EUV mirror. The fabrication method has another merit to ...

KoreaScience (Korea)

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UK PubMed Central (United Kingdom)

PURPOSEThe purpose of this study was to compare the linear sintering behavior of presintered zirconia blocks of various densities. The mechanical properties of the resulting sintered...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Mesoporous films of platinized carbon nanotube-zirconia-Nafion composite have been used for the immobilization of tris(2,2prime-bipyridyl)ruthenium (II) (Ru(bpy)32+) on an electrode surface to yield a solid-state electrogenerated chemiluminescence (ECL) sensor. The composite films of Pt-CNT-zirconia-Nafion exhibit much larger pore diameter (3.55 nm) than that of Nafion (2.82 nm) and thus leading to much larger ECL response for tripropylamine (TPA) because of the fast diffusion of the analyte within the films. Due to the conducting and electrocatalytic features of CNTs and Pt nanoparticles, their incorporation into the zirconia-Nafion composite films resulted in the decreased electron transfer resistance within the films. The present ECL sensor based on the Pt-CNT-zirconia-Nafion gave a lin...

British Library Electronic Table of Contents (United Kingdom)

High lithium-ion (Li^+) conductive garnet-structured lanthanum lithium zirconate (LLZ) solid electrolyte is prepared by incorporation of appropriate amounts of silicon (Si) and aluminum (Al). The resultant pelletized LLZ obtains total Li^+ conductivity of 6.8x10^-^4Scm^-^1 at 298K. This improved conductivity is nearly identical with the bulk Li^+ conductivity of the LLZ reported earlier, suggesting that the grain boundary resistance is effectively reduced by the incorporation of Si and Al. Microanalyses by transmission electron microscopy coupled with energy-dispersive X-ray microanalysis and electron energy-loss spectroscopy revealed the presence of amorphous Li-Al-Si-O with nano crystalline LiAlSiO4 at grain boundaries. Fast lithium-ion transport around the amorphous Li-Al-Si-O/LiAlSiO4 ...

International Nuclear Information System (INIS)

Mixed additions of Sm_2O_3 and Y_2O_3 were used in the formation of zirconia-containing O'-sialon composites, where Sm_2O_3 was used for the purpose of densification and Y_2O_3 for zirconia stabilization. Dense ZrO_2/O' -sialon composites were produced at 1500 deg C. by sintering in nitrogen for 4 hours. Tetragonal zirconia remained in the product and t#->#m transformation was observed when the sample was ground into powder. However, the improvement in fracture toughness was not significant and this was attributed to the weakened transformability of the tetragonal zirconia phase in the nitrogen-based materials. 18 refs., 4 tabs., 2 figs.

International Nuclear Information System (INIS)

... structure crystal-phase transformations fluorescence fluorescence spectroscopy

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The development of nano/molecular devices will require atomic-sized electrical contacts or nano metric conductors for wiring. As metal nano wires exhibit quantized conductance at room temperature, quantum transport effects will play an important role in the practical implementation of nano devices. As copper is currently used as interconnecting metal in standard microelectronics, the characterization of Cu nano wire properties deserves special attention. In this work, we show a detailed study of structural and electronic properties of atomic-sized Cu wires. In particular, we have established a complete correlation between the conductance and the structure by associating real-time atomic resolution transmission electron microscopy imaging with molecular dynamic simulations, conductance measurements and conductance calculations. Our study has revealed the structural relaxation of Cu ...

British Library Electronic Table of Contents (United Kingdom)

Objectives: The aim of this study was to evaluate the in vitro behaviour of all-ceramic zirconia molar crowns in regard to different core designs and marginal fit. Methods: Identically shaped methacrylate molars were prepared according to the ceramic restoration directives resulting in a 1-mm deep circular shoulder preparation. They were embedded in polymethylmethacrylate resin after covering their roots with a polyether layer to simulate periodontal mobility. The crown cores were made of yttria-stabilized zirconia veneered with a corresponding veneering ceramic. The crowns were divided into 5 groups (n=8) which differed in core design and cement gap thickness: #1: simple core, 40mm cement; #2: core with minimal occlusal support, 40mm cement; #3: core with optimized cusp support, 40mm ceme...

UK PubMed Central (United Kingdom)

In this study, we report the physico-chemical and biological properties of a novel biodegradable composite scaffold made of nano-hydroxyapatite and natural derived polymers of chitosan and carboxymethyl...Full Text Available

International Nuclear Information System (INIS)

... 30-31 Oct 2009 Tajik National University(Tajikistan) 146 p. INORGANIC,

International Nuclear Information System (INIS)

The existence of characteristic longitudinal optical and transverse optical phonons of cubic ZnO in ZnO nano-tetrapods is determined by Raman spectroscopy and first-principles calculations. Stacking sequence change at the boundary of the core and legs is also identified by high-resolution transmission electron microscopy. Based on this experimental and theoretical evidence, we demonstrate that the lattice structure of ZnO nano-tetrapods is hierarchical with a zinc blende core connecting to four wurtzite legs. Furthermore, we establish the atomic configuration and propose a formation mechanism induced by Laplace pressure in the initial growth stage of ZnO nano-tetrapods.

UK PubMed Central (United Kingdom)

PurposeThe aim of this investigation was to exploit lens-specific glycated crystallins as an immunogen to detect human glycated crystallins and their circulating autoantibodies in...Full Text Available

Wastenet

the low levels of crystalline silica in this product, chronic health effects are not anticipated with normal

Energy Technology Data Exchange (ETDEWEB)

Nano-materials in which a large fraction of atoms resides within a few atomic layers near the surface can be designed to have novel properties by manipulating their surface parameters. We show that the effective elastic constants of nano-porous/cellular materials can be made to exceed those of the parent materials provided the pore surface elastic parameters satisfy certain conditions. These stiff nano-porous materials herald a radical breakthrough in sandwich-type construction.

International Nuclear Information System (INIS)

Nano-indentation has been used to assess the hardness of equiaxed grains of #alpha#-Ti as a function of orientation. Surface normals of these grains in metallographic sections were assessed using orientation imaging microscopy. Thin membranes of material from below a series of nano-indentations were excised by use of a dual-beam focused ion beam instrument. In this way, the dislocation substructures beneath individual indentations were characterized using transmission electron microscopy, permitting an identification of both statistically stored and geometrically necessary dislocations.

British Library Electronic Table of Contents (United Kingdom)

The present study is focused on preparation of nano composite materials and the effect of citric acid on their different properties. The formation of nano HA and its interaction with chitosan (C), gelatin (G) polymers and citric acid (CA) materials were studied. The Fourier Transformed Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM), and scanning electron microscope (SEM) were used to characterize these composite materials. The compressive strength (CS) was also measured to know the reinforcement of the prepared composites. The results show that carboxylic and amino groups play crucial role for HA formation on chitosan-gelatin polymeric matrix in the presence of citric acid (CA). The formation of nano HA part...

British Library Electronic Table of Contents (United Kingdom)

Nano-sized silica is a promising material for disease diagnosis, cosmetics and drugs. For the successful application of nano-sized material in bioscience, evaluation of nano-sized material toxicity is important. We previously found that nano-sized silica particles with a diameter of 70nm showed acute liver failure in mice. Here, we performed histological analysis of major organs such as the liver, spleen, lung, kidney, brain and heart in mice, chronically injected with 70-nm silica particles for 4weeks. Histological analysis revealed hepatic microgranulation and splenic megakaryocyte accumulation in these 70-nm silica particles treated mice, while the kidney, lung, brain and heart remained unaffected. Thus, liver and spleen appear to be the major target organs for toxicity by the chronic a...

Energy Technology Data Exchange (ETDEWEB)

The large uranium fission cross section leading to iodine and the behaviour of this element in the cladding tube during energy production and afterwards during waste storage is a crucial problem, especially for {sup 129}I which is a very long half-life isotope (T=1.59 x 10{sup 7} yr). Since a combined external and internal oxidation of the zircaloy cladding tube occurs during the reactor processing, iodine diffusion parameters in zirconia are needed. In order to obtain these data, stable iodine atoms were first introduced by ion implantation into zirconia with an energy of 200 keV and a dose equal to 8 x 10{sup 15} at cm{sup -2}. Diffusion profiles were measured using 3 MeV alpha-particle Rutherford backscattering spectrometry at each step of the annealing procedure between 700 C and 900 C. In such experiments a reduced iodine concentration was observed, which correlated to a diffusion-like process. Similar analysis has been performed using ...

International Nuclear Information System (INIS)

Twelve powders of TiO_2-Y_2O_3-ZrO_2 solid solution of the methodically changed composition were prepared by a coprecipitation-calcination technique. After mixing with phenol-formaldehyde resin, the powders were calcinated for 2 hours at 1200"oC in vacuum. The resultant composite powders contained TiC and non-reacted carbon. Green compacts were sintered in vacuum at 1500"oC for 2 hours. A temperature increase was stopped at 1200"oC to react remains of carbon. There were two carbides in the composites TiC and ZrC. TiC non-stoichiometry depended on carbon content in the system. Phase composition of the depended on of titania and yttria in zirconia solid solution. The majority of the samples showed two tetragonal zirconia phases differing in lattice parameter and tetragonality. (author)

Energy Technology Data Exchange (ETDEWEB)

Nanocrystalline cemented tungsten carbide has attracted considerable interests for use in cutting tool because of its superior mechanical properties. In this study, nano-sized powders of mixed WC and Co were prepared from attrition-milled oxides by a gas reduction-carburization process. The effects of compacting pressure, heating schedule, additional ball-milling, and the presence of a grain growth inhibitor on the sintering properties of the nano-sized WC-Co powders were examined. The grain size and phases in WC-Co alloy were clearly affected by compacting pressure. Because of the trapped gases and the lower melting point of the cobalt binder, when a compact of nano-sized WC-Co powder was sintered through a heating schedule with holding steps, the sintered alloy maintained the small size of WC grains without any {eta} phase. In addition, the additional ball-milling improved the microstructure and mechanical properties of ...

International Nuclear Information System (INIS)

We report a new method of generating nano and micro patterns using focused ion beam (FIB) induced adhesion. The method utilizes selective irradiation of thin metallic films grown on substrates by focused ion beam followed by peel off. After peel off of the irradiated thin film it is observed that the ion beam scanned portions are retained on the substrate, creating nano and micro patterns. The method is suitable for materials of which the adhesion to the substrate can be improved by ion bombardment. The phenomenon has been demonstrated by creating gold nano patterns of different shapes and sizes ranging from 500 nm to 5 #mu#m on SiO_2-Si substrate using 10-30 keV Ga FIB at beam currents up to 10 pA. The mechanism involved in the process has been discussed. The technique could be utilized to prepare micro and nano patterns of thin films deposited on an appropriate substrate for optical, plasmonic and ...

International Nuclear Information System (INIS)

Iron oxide as sintering aid to Ce-TZP ceramics produces a beneficial effect on the tetragonal phase stabilization. It was found that ceria powder particle size of 2,0 #mu#m turns the grain-boundary electrical conductivity higher than ceria powder of smaller grain size. (author)

UK PubMed Central (United Kingdom)

Plant surfaces covered with crystalline epicuticular waxes are known to be anti-adhesive, hardly wettable and preventing insect attachment. But there are insects that are capable of gluing their eggs...Full Text Available

International Nuclear Information System (INIS)

... susceptibility magnetization magnetoresistance monocrystals order-disorder

Science.gov (United States)

Feasibility of depositing continuous films of nano-porous alumino-silicates, primarily zeolites and MCM-41, on metallic and non-metallic substrates was examined with an aim to develop membranes for separation of gaseous mixtures and also for application as hydrogen storage material. Mesoporous silica was deposited in-side the pores of these nano-porous disks with an aim to develop membranes for selective separations. Our study involves supported zeolite film growth on substrates using in-situ hydrothermal synthesis. Faujasite, Silicalite and Mesoporous silica have been grown on various metallic and non-metallic supports. Metallic substrates used for film growth included anodized titanium, sodium hydroxide treated Titanium, Anodized aluminum, and sintered copper. A non-metallic substrate used was nano-porous aluminum oxide. Zeolite film growth was characterized using Scanning Electron Microscope (AMRAY 1820) and High ...

British Library Electronic Table of Contents (United Kingdom)

AbstractBackground In recent years nano-metaloxides which easily penetrate into the cells with special interest due to their higher chemical reactivity as compared to that of similar materials in the bulk form. Of particular interest are nano-TiO2 and ZnO, which have been widely used for their bactericidal and anticancerous properties. Purpose The aim of the present study was to examine the bactericidal properties of nano-TiO2 and ZnO combined with visible light on S. aureus and S. epidermitis, known for their high prevalence in infected wounds. Study Using the technique of electron-spin resonance (ESR) coupled with spin trapping, we examined the ability of TiO2 and ZnO nanoparticle suspensions in water to produce reactive oxygen species (ROS) with and without visible light irradiation. Th...

International Nuclear Information System (INIS)

When liquids are confined in nano-scopic dimensions, their properties differ from the corresponding bulk liquid, due to their reduced dimensionality and surface effects. Phase transition temperatures and pressures are often shifted from the bulk values and new phases can appear due to the strong interactions of the molecules with the confining walls. We have studied the structural and dynamical properties of aromatic liquids such as benzene, toluene, and ortho-terphenyl confined in nano-porous materials, MCM-41 and SBA-15, synthesized and characterized in our laboratory. A non-trivial dependence of the glass transition temperature, Tg, on the pore size and surface treatment of nano-porous materials is confirmed and interpreted as resulting from a competition between the fluid-wall and fluid-fluid intermolecular interactions. An increase of Tg is observed for small pore sizes and attractive surface while Tg decreases for non ...

International Nuclear Information System (INIS)

... NOU TsIPK; Obninsk (Russian Federation) 978-5-85855-125-6 208 p.

Science.gov (United States)

... materials science and education beyond what is expected from any one Center. "Advanced materials are ... for DMR's Division of Materials Research. "Fundamental research on materials is essential to the ...

Wastenet

... In recent years workers in this field have focused on nucleation by nano-porous materials . This was in part motivated by a theoretical study by Page and Sear (2006) who proposed a two step model for nucleation in pores which suggest that there is ...

International Nuclear Information System (INIS)

For the advanced fusion reactor FFHR2 (Force Free Helical Reactor) that has been proposed by NIFS, molten salt Flibe (LiF:BeF2=64:36) breeder blanket system is selected because of Flibe's features such as chemical stability, low-pressure operation and low electric conductivity. The Flibe is however high Prandtl number fluid since it has high viscosity and low thermal conductivity. Therefore its heat transfer performance is low compared with liquid Li or Pb-Li. In addition to heat removal of 1MW/m2 on the first wall, electrolysis of molten salt due to MHD effect will take place under high flow rate condition. This indicates that heat transfer enhancement under low flow rate is essential for the Flibe blanket system. In our laboratory, heat transfer characteristics of molten salt HTS (KNO3:NaNO2:NaNO3=53:40:7), have been evaluated, which is used as a simulant fluid of Flibe from the points of view of Be's toxicity and similar Prandtl number. In ...

Energy Technology Data Exchange (ETDEWEB)

In this project we developed photonic crystal modeling capability and fabrication technology that is scaleable to large area. An intelligent optimization code was developed to find the optimal structure for the desired spectral response. In terms of fabrication, an exhaustive survey of fabrication techniques that would meet the large area requirement was reduced to Deep X-ray Lithography (DXRL) and nano-imprint. Using DXRL, we fabricated a gold logpile photonic crystal in the <100> plane. For the nano-imprint technique, we fabricated a cubic array of gold squares. These two examples also represent two classes of metallic photonic crystal topologies, the connected network and cermet arrangement.

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Energy and environment are two major concerns in our modern society due to the coming shortage in fossil energy sources and the growing of greenhouse gas emissions. The challenge for the coming years is to discover new energy resources and to develop devices that are compatible with a sustainable development and generate few (or zero) emission. One of these devices is the fuel cell feed by hydrogen, whose application fields are very large. In particular, the proton exchange membrane fuel cell (PEMFC) is the most realistic device for automotive application. However, hydrogen storage remains one of the most important challenges regarding its development. Although different techniques are available for storing hydrogen, no ideal solution has been found yet. Compression needs elaborated tanks in shape for supporting high pressures, liquefaction requires an expensive hydrogen cooling and adapted tanks. Chemical storage by hydrides imposes heavy devices. A ...

Energy Technology Data Exchange (ETDEWEB)

In order to investigate the role of amorphous SiO{sub 2} particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO{sub 2} was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO{sub 2} particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of {gamma}-phase and amorphous nano-SiO{sub 2} particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO{sub 2} particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite ...

Energy Technology Data Exchange (ETDEWEB)

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.

International Nuclear Information System (INIS)

Highly conductive biaxially textured RuO_2 thin films were deposited on technically important SiO_2/Si substrates by pulsed laser deposition, where yttria-stabilized zirconia (YSZ) produced by ion-beam-assisted-deposition (IBAD) was used as a template to enhance the biaxial texture of RuO_2 on SiO_2/Si. The biaxially oriented RuO_2 had a room-temperature resistivity of 37 #mu##OMEGA#-cm and residual resistivity ratio above 2. We then deposited Ba_0_._5Sr_0_._5TiO_3 thin films on RuO_2/IBAD-YSZ/SiO_2/Si. The Ba_0_._5Sr_0_._5TiO_3 had a pure (111) orientation normal to the substrate surface and a dielectric constant above 360 at 100 kHz. copyright 1998 Materials Research Society.

Energy Technology Data Exchange (ETDEWEB)

A study has been made of the precipitation and growth processes which occur during cooling from solution treatment and under isothermal hold conditions in a magnesia-partially-stabilized zirconia alloy. Three types of precipitate have been identified which develop during cooling or during isothermal hold treatments just above and below the eutectoid temperature. These precipitate forms are termed (i) primary, (ii) large random, and (iii) secondary. Further precipitation, slow growth of existing precipitates, and subeutectoid decomposition result when an additional 1100/sup 0/C aging treatment is given to the previously cooled material. It is shown that type (iii) secondary precipitates from rapidly within the temperature range of 1300/sup 0/ to 1375/sup 0/C. The secondary precipitates are largely responsible for the improved room-temperature strength properties of the heat-treated samples. The formation and effects on mechanical properties of each type of ...

Energy Technology Data Exchange (ETDEWEB)

Anisotropy finite element analysis was performed to study stresses associated with the tetragonal precipitates and the tetragonal to monoclinic transformation in MgO partially stabilized zirconia. Stresses were assumed to be caused by the lattice misfits between the product phase and the parent phase. In the finite element calculations, the tetragonal and monoclinic precipitates were assumed to be lenticular in shape, and the anisotropic elastic constants of the cubic, tetragonal and monoclinic phases were considered. The purpose of this paper is to obtain some knowledge about how stresses respond when the microstructure is changed, and how stress fields affect microstructure development. The finite element results show that increasing a{sub t}/a{sub c} and decreasing c{sub t}/a{sub c} can create a favorable stress field to reduce the growth rate of tetragonal precipitates during the heat treatment. Stresses associated with the single tetragonal precipitate in an ...

International Nuclear Information System (INIS)

This paper presents the results of experimental study carried out to know whether the salicylic acid used as an additive during the precipitation of zirconium using ammonium hydroxide solution goes into the filtrate, remains in the hydrated zirconia or gets distributed between the both under the ambient conditions of precipitation. Keeping its simplicity and amenability to adopt on a routine basis, spectrophotometric method has been chosen for the purpose among the many methods available and the problems associated in determining salicylic acid in the presence of zirconium and the medial measures to circumvent the same have been brought out in detail. (author)

British Library Electronic Table of Contents (United Kingdom)

Due to the low thermal conductivity of ceramics large temperature gradients are present through the powder particles during plasma spray deposition. As a result the particles often impinge at the substrate in a semi-molten form; which in turn substantially affects the final characteristics of the coating being formed. This study is dedicated to the novel modelling development and simulation of a semi-molten droplet impingement. The study examines the impingement process during impact, spreading and solidification of semi-molten zirconia. The simulation provides an insight to the heat transfer process during impact and solidification of a semi-molten powder particle and illustrates the freezing-induced break-up mechanism at the splat periphery.

International Nuclear Information System (INIS)

Suspension direct current plasma spraying allows achieving finely structured coatings whose thickness is between few tens and few hundreds of micrometres. Drops (200-300 ?m in diameter) or liquid jets are mechanically injected in the plasma jet. With radial injection they are rapidly (a few ?s) fragmented into droplets (a few ?m in diameter). The latter are vaporized (in a few ?s) and the solid particles contained in suspension droplets are accelerated and melted by the plasma jet. As in conventional plasma spraying (CPS), much smaller splats (with diameters between 0.2 and 3 ?m and thicknesses between 30 and 200 nm) are arranged in layers up to form the coating. The low inertia of particles requires spray distances between 40 and 60 mm which induces plasma heat fluxes up to 22 MW m-2 participating in coating densification. Even more than in CPS, the plasma jet fluctuations, particularly for plasmas containing di-atomic gases, perturb drops penetration and fragmentation. It has been ...

Energy Technology Data Exchange (ETDEWEB)

Experiments were conducted which established that the higher passivating capacity of Ni/sub 60/Nb/sub 40/ alloys in the amorphous state and higher efficiency of the anodic process of generation of chlorine (2 N NaCl + HCl to pH = 0) in comparison with the crystalline state are determined by higher homogeneity and density of the passive films formed on the amorphous alloy and by higher electron conduction which depends directly on the difference in the structure of the passive films formed on the alloys in the amorphous and crystalline states.

British Library Electronic Table of Contents (United Kingdom)

Crystalline silicotitanate inorganic ion exchanger, with a sitinakite structure is candidate material for remediation of aqueous nuclear waste streams. The syntheses of crystalline silicotitanate (CST) and Nb-substituted crystalline silcotitanate (Nb-CST) were carried out under hydrothermal conditions and the products were characterized using techniques viz., XRD, SEM/EDS, DTA/TGA, surface area respectively. Batch experiments were carried out to study the kinetics of uptake of 137Cs and 90Sr, to estimate the decontamination factor (DF) values and distribution coefficients (K d) for the above synthesized CST and Nb-CST samples from actual radioactive waste solutions. The DF values for uptake of Cs and Sr by Nb-CST after 24?h of equilibration was 355 and 136 whereas for CST it was found to b...

Science.gov (United States)

... MPS) Advanced Liquid Crystalline Optical Materials Superconductivity Computation and Visualization ... Cement-Based Materials Synthesis, Growth, and Analysis of Electronic Materials Photoinduced Charge ...

UK PubMed Central (United Kingdom)

Lens-induced glaucoma comprises a number of different glaucomatous processes occurring in the elderly that share in common the role of the crystalline lens in the mechanism of increase in intraocular...Full Text Available

International Nuclear Information System (INIS)

This paper deals with preparation of PE clay nano composite specimen for transmission electron microscopy (TEM) and studying the difference between dispersion of clay in low density polyethylene using poly(hydrogen methyl siloxane) (PHMS) as coupling agent and untreated one. Argon ion milling is the conventional means by which film sections are thinned to electron transparency for TEM analysis, but this technique exhibits significant problems. In particular, selective thinning and imaging of sub-micrometer inclusions during sample milling are highly problematic. We have achieved successful results using the focused ion beam (FIB) lift-out technique, which utilizes a 30 kV Ga"+ ion beam to extract electron transparent specimens with nanometer scale precision. Using this procedure, we have prepared a number of thin film materials representing a range of structures and compositions for TEM analysis. We believe that FIB milling will create major new opportunities in ...

Science.gov (United States)

A process is provided for conducting organic compound conversion over a catalyst composition comprising a supported crystalline zeolite having a high initial silica-to-alumina mole ratio, said supported zeolite being prepared by compositing said crystalline zeolite with alumina, reacting the composite with a particular hydrogen fluoride solution in a specified way, drying the hydrogen fluoride reacted composite, treating the dried composite by hydrolysis, ammonolysis and/or by contact with an ammonium salt solution, and calcining the resulting material.

International Nuclear Information System (INIS)

Planar channeling effects are studied in such well-oriented polycrystalline layers as NiSi_2 and Pb_2Si layers formed on single crystalline Si. Crystalline perfection of such layers is discussed by using the energy- and angular dependences of the axial and planar channeling yields. It has been shown that, in suitable conditions, the energy dependence of the planar yield is more sensitive to the spread of crystallite orientations in polycrystals than that of the axial one. (Auth.).

British Library Electronic Table of Contents (United Kingdom)

TaC and TaC-1wt.% B4C powders were consolidated using spark plasma sintering (SPS) at 1850^oC and varying pressure of 100, 255 and 363MPa. The effect of pressure on the densification and grain size is evaluated. The role of nano-sized B4C as sintering aid and grain growth inhibitor is studied by means of XRD, SEM and high resolution TEM. Fully dense TaC samples were produced at a pressure of 255MPa and higher at 1850^oC. The increasing pressure also resulted in an increase in TaC grain size. Addition of B4C leads to an increase in the density of 100MPa sample from 89% to 97%. B4C nano-powder resists grain growth even at high pressure of 363MPa. The formation of TaB2/Carbon at TaC grain boundaries helps in pinning the grain boundary and inhibiting grain growth. The effect of B4C addition on...

International Nuclear Information System (INIS)

Proton exchange membrane fuel cells (PEMFCs) are attractive because of their high conversion efficiency, low pollution, lightweight, and high power density. A major area of challenges is the design and engineering of active, robust, and low-cost electrocatalysts. This report discusses recent findings of our investigations of the design and nano-engineering of platinum-vanadium-iron catalysts for use in PEMFC. The membrane electrode assembly was prepared using nano-engineered PtVFe nanoparticles with controlled composition and size supported on carbon as cathode electrocatalysts. The electrocatalytic activity and stability of the catalysts have been characterized by both rotating disk electrode and membrane electrode assembly measurements. The trimetallic catalysts have been shown to exhibit excellent electrocatalytic performance in PEMFC in comparison with commercial platinum catalysts. The results exhibited a good agreement between obtained ...

International Nuclear Information System (INIS)

Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite nano-catalysts can be implemented for a ...

Energy Technology Data Exchange (ETDEWEB)

A single particle micro-electrode technique has been applied, to study adsorption and mass transport phenomena of a TEABF{sub 4}/acetonitrile solution in a nano-porous carbon. The nano-porous carbon, which is obtained from SiC, has a very small and narrow pore size distribution around 8 Angstrom. Therefore, it is a good model material for studying adsorption processes in micropores. The results from cyclic voltammetry showed that a higher specific capacitance was obtained in the positive potential interval (vs Ag/AgNO{sub 3}). Upon activation cycling the mass transport inside the nano-porous particle becomes drastically hindered, probably by TEA{sup +} that is adsorbed and is partially blocking the micropores. Effective diffusion coefficients, Deff, were determined from potential step experiments. At positive potentials Deff was 1.5 {+-} 0.5 x 10{sup -8} cm{sup 2}s{sup -1}, whereas at more negative potentials Deff decreased ...

International Nuclear Information System (INIS)

Olfactory tract has been demonstrated to be an important portal for inhaled solid nanoparticle transportation into the central nervous system (CNS). We have previously demonstrated that intranasally instilled Fe_2O_3 nanoparticles could transport into the CNS via olfactory pathway. In this study, we investigated the neurotoxicity and size effect of repeatedly low-dose (130 #mu#g) intranasal exposure of nano- and submicron-sized Fe_2O_3 particles (21 nm and 280 nm) to mice. The biomarkers of oxidative stress, activity of nitric oxide synthases and release of monoamine neurotransmitter in the brain were studied. Our results showed that significant oxidative stress was induced by the two sizes of Fe_2O_3 particles. The activities of GSH-Px, Cu,Zn-SOD, and cNOS significantly elevated and the total GSH and GSH/GSSG ratio significantly decreased in the olfactory bulb and hippocampus after the nano- and submicron-sized Fe_2O_3 particle treatment (p ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Aims: To develop a new nano composite of multi walled carbon nanotubes (MWNTs) with enhanced antimicrobial activity. Methods and Results: A novel antimicrobial nanocomposite [MWNT epilson polylysine (MEPs)] was synthesized via covalent attachment of epilson polylysine on MWNTs with hexamethylene diisocyanate (HDI) as the coupling agent. UV visible spectra and Fourier transform infrared spectra (FT IR) investigations indicate that MEPs is stable, with epilson polylysine leaching effectively eliminated. When compared to MWNTs, the new nano composite MEPs exhibits enhanced antimicrobial activities. In 20 mg l 1 suspensions, significant increases of 72 1, 64 5 and 69% against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus can be observed. The deposited film of MEPs...

International Nuclear Information System (INIS)

Nano indentation analysis and transmission electron microscopy observation were performed to investigate a microstructural evolution and its influence on the hardening behavior in Fe-Cr alloys after an irradiation with 8 MeV Fe4+ ions at room temperature. Nano indentation analysis shows that an irradiation induced hardening is generated more considerably in the Fe-15Cr alloy than in the Fe-5Cr alloy by the ion irradiation. TEM observation reveals a significant population of the a0 dislocation loops in the Fe-15Cr alloy and an agglomeration of the 1/2a0 dislocation loops in the Fe-5Cr alloy. The results indicate that the a0 dislocation loops will act as stronger obstacles to a dislocation motion than 1/2a0 dislocation loops.

International Nuclear Information System (INIS)

Nano structured carbon nitride thin films were deposited at different RF powers in the range of 50 W to 225 W and constant gas ratio of (argon: nitrogen) Ar:N_2 by RF magnetron sputtering. The atomic percentage of Nitrogen: Carbon (N/C) content and impedance of the films increased from 14.36% to 22.31% and 9 x 10"-"1 #OMEGA# to 7 x 10"5 #OMEGA# respectively with increase in RF power. The hardness of the deposited films increased from 3.12 GPa to 13.12 GPa. The increase in sp"3 hybridized C-N sites and decrease of grain size with increase in RF power is responsible for such variation of observed mechanical and electrical properties.

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Statistically based experimental designs were applied to screen and optimize the bioleaching of spent hydrocracking catalyst by Penicillium simplicissimum. Eleven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design. Four significant variables (pulp density, sucrose, NaNO"3, and yeast extract concentrations) were selected for the optimization studies. The combined effect of these variables on metal bioleaching was studied using a central composite design (CCD). Second-order polynomials were established to identify the relationship between the recovery percent of the metals and the four significant variables. The optimal values of the variables for maximum metals bioleaching were as follows: pulp density (4.0%, w/v), sucrose (90g/L), NaNO"3 (2...

British Library Electronic Table of Contents (United Kingdom)

Direct electrochemistry and electrocatalysis of catalase (Cat) was studied based on a nano-composite film consisting of amine functionalized graphene and gold nanoparticles (AuNPs) modified glassy carbon electrode. Graphene was synthesized chemically by Hummers and Offeman method and then was functionalized with amino groups via chemical modification of carboxyl groups introduced on the graphene surface. The nano-composite film showed an obvious promotion of the direct electron transfer between Cat and the underlying electrode, which attributed to the synergistic effect of graphene-NH2 and AuNPs. The resultant bioelectrode retained its biocatalytic activity and offered fast and sensitive H2O2 quantification. Under the optimized experimental conditions, hydrogen peroxide was detected in the...

British Library Electronic Table of Contents (United Kingdom)

An electrochemical biosensor for determination of hydrogen peroxide (H2O2) was fabricated, based on the electrostatic immobilization of horseradish peroxidase (HRP) with one-dimensional gold nanowires (Au NWs) and TiO2 nanoparticles (nano-TiO2) on a gold electrode. The nano-TiO2 can give a biocompatible microenvironment and compact film, and the Au NWs can provide fast electron transferring rate and greatly add the amount of HRP molecules immobilized on the electrode surface. Au NWs were characterized by ultraviolet?visible spectra and transmission electron microscope. The electrode modification process was probed by cyclic voltammetry and electrochemical impedance spectroscopy. Chronoamperometry was used to study the electrochemical performance of the resulting biosensor. Under optimal co...

Energy Technology Data Exchange (ETDEWEB)

In support of the efforts to apply ceramics to advanced heat engines, a study is being performed of the performance of ceramics at the ring/cylinder interface of advanced (low heat rejection) engines. The objective of the study, managed by the Oak Ridge National Laboratory, is to understand the basic mechanisms controlling the wear of ceramics and thereby identify means for applying ceramics effectively. Attempts to operate three different zirconias, silicon carbide, silicon nitride, and plasma-sprayed ceramic coatings without lubrication have not been successful because of excessive friction and high wear rates. Silicon carbide and silicon nitride perform well at ambient temperatures with fully formulated mineral oil lubrication, but are limited to temperatures of 500F because of the lack of suitable liquid lubricants for higher temperatures.

British Library Electronic Table of Contents (United Kingdom)

Abstract Within the framework of the CRC 799 -TRIP-Matrix-Composites- at the TU Bergakademie Freiberg new composite materials consisting of TRIP steel and zirconium dioxide ceramics are designed in a powder route and a casting route. To manufacture faultless samples basic investigations of the feeding and infiltration behaviour within macro porous ceramics such as filters were needed. The effects of bottom pouring and top pouring were investigated as well as the effects of different preheating temperatures, contents of phosphorous in the steel and flow trough rates. Bottom pouring corrupts the feeding mainly of filters with high ppi (pores per inch). Top pouring improves the feeding, but generates inhomogeneous infiltration qualities, which can affected and enhanced by a increasing preheat...

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Objective.The interest of dental research in metal-free restorations has been rising in the last 20 years following the introduction of innovative all-ceramic materials in the daily practice. In particular, high strength ceramics and related CAD/CAM techniques have widely increased the clinical indications of metal-free prostheses, showing more favourable mechanical characteristics compared to the early ceramic materials.The purpose of the present paper is providing a brief review on the all-ceramic dental materials, evaluating pros and cons in the light of the most recent scientific results and of the authors? clinical experience.Materials. A structured review of the literature was given on the basis of medical and engineering papers published in the last decades on the use of dental cera...

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Purpose Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Design Optical radiation measurement, analysis, and perspective. Methods Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Results Crystalline lens UV-B retinal protection is deficient in children and young adults, incre...

International Nuclear Information System (INIS)

#beta#-sialon ceramics of equal overall compositions but containing amorphous, partly crystalline and almost completely crystalline intergranular phase(s) have been oxidized in oxygen at 1350 deg C for 20 hours. The obtained weight gain curves do not follow the parabolic rate law (#DELTA#W/A_0)"2= k_pt + #beta#. To the extent that crystallization occurs in the oxide scale during the oxidation experiment, the amorphous cross section area through which oxygen most easily diffuses will decrease with time. A brief description of this new rate law is given, and the obtained oxidation curves will be discussed within that framework. 4 refs., 2 tabs., 2 figs.

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When liquids are confined in nano-scopic dimensions, their properties differ from the corresponding bulk liquid, due to their reduced dimensionality and surface effects. Phase transition temperatures and pressures are often shifted from the bulk values and new phases can appear due to the strong interactions of the molecules with the confining walls. We have studied the structural and dynamical properties of aromatic liquids such as benzene, toluene, and ortho-terphenyl confined in nano-porous materials, MCM-41 and SBA-15, synthesized and characterized in our laboratory. A non-trivial dependence of the glass transition temperature, T{sub g}, on the pore size and surface treatment of nano-porous materials is confirmed and interpreted as resulting from a competition between the fluid-wall and fluid-fluid intermolecular interactions. An increase of T{sub g} is observed for small pore sizes and attractive surface while T{sub g} ...

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The physics and technology of a new class of efficient composite piezoelectrics are described. This material combines nanostructured and micropiezoelectric matrix composites. They consist of a polymer matrix, an insulating nanodimensional phase, and a microdimensional piezoelectric phase. It is shown that the nanostructuring of the near-surface region of polymer-PZT piezoelectric composites greatly improves their piezoelectric, mechanical, and electromechanical characteristics. A plausible mechanism underlying this effect is suggested.

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Formaldehyde, a well-identified indoor pollutant, was recently classified as carcinogenic. New regulations for the air quality are expected and therefore there is a need for low-cost sensors, sensitive and selective with a fast response time for the detection of formaldehyde at ppb level. In the present work, we had developed a chemical sensor based on nano-porous matrices doped with Fluoral-P and optical methods of detection. The nano-porous matrices, elaborated via the Sol-Gel process, display nano-pores whose cavity is tailored for the trapping of the targeted pollutant. They provide a first selectivity with the discrimination of the pollutants by their size. A second selectivity is obtained with a molecular probe, Fluoral-P, which reacts specifically with formaldehyde leading to the 3,5- di-acetyl-1,4-dihydro-lutidine (DDL). The kinetics of formation of DDL was studied as function of many parameters such as the ...

Environmental Research Database

Objectives1) To establish a protocol for transfection of immortalised type I cells with SiRNA and its effect on cell viability; 2) To optimise silencing of genes involved in endocystosis using SiRNA and confirm successful transfection with western blotting; 3) To investigate the effect of gene silencing on uptake of flourescently-labelled latex nanoparticles.DescriptionTo investigate the mechanisms of particle uptake.

Environmental Research Database

DescriptionThe objective is to exploit the use of wheat as an industrial raw material and understand the effect of material variation in wheat starch and flour on final material properties for food packaging applications. The project will focus on property enhancement in terms of stiffness, strength, toughness, moisture barrier resistance, transparency, ageing resistance, microbial stability and biodegradability of starch-based packaging materials made by sheet extrusion and thermoforming processes, in ord [continued...

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Damage and cyclic fatigue failure under alternating loading in transformation-toughened zirconia ceramics is reviewed and compared to corresponding behavior under quasi-static loading (static fatigue). Current understanding of the role of transformation toughening in influencing cyclic fatigue-crack propagation behavior is examined based on studies which altered the extent of the tetragonal-to-monoclinic phase transformation in MG-PSZ through subeutectoid aging. These studies suggest that near-tip computations of the crack-driving force (in terms of the local stress intensity) can be used to predict crack-growth behavior under constant amplitude and variable-amplitude (spectrum) loading, using spatially resolved Raman spectroscopy to measure the extent of the transformation zones. In addition, results are reviewed which rationalize distinctions between the crack-growth behavior of preexisting, long'' (> 2 mm), through-thickness cracks and ...

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The contaminants that are potentially present in the coal-derived gas stream and their thermochemical nature are discussed. Accelerated testing was carried out on Ni-YSZ/YSZ/LSM solid oxide fuel cells (YSZ: yttria stabilized zirconia and LSM: lanthanum strontium manganese oxide) for eight main kind of contaminants: CH{sub 3}Cl, HCl, As, P, Zn, Hg, Cd and Sb at the temperature range of 750-850 C. The As and P species, at 10 and 35 ppm, respectively, resulted in severe power density degradation at temperatures 800 C and below. SEM and EDX analysis indicated that As attacked the Ni region of the anode surface and the Ni current collector, caused the break of the current collector and the eventual cell failure at 800 C. The phosphorous containing species were found in the bulk of the anode, they were segregated and formed ''grain boundary'' like phases separating large Ni patches. These species are presumably nickel ...

International Nuclear Information System (INIS)

Low-temperature #gamma# radiolysis and photolysis of crystalline 2,4,6-triazido-3,5-dichloropyridine (TAP) were studied by means of the ESR technique. It was found that the long-term irradiation of TAP at 77 K leads to the appearance of characteristic signals of quintet 2,6-dinitreno-4-azido-3,5-dichloropyridine and 2,4-dinitreno-6-azido-3,5-dichloropyridine; the radiation-chemical yield was 0.035 and 0.012 molecule/100 eV, respectively. The photolysis of crystalline 2,4,6-triazido-3,5-dichloropyridine proceeded less effectively, producing only quintet 2,6 dinitrene with a quantum yield of #approx#4.5 x 10"-"4. The study showed that the generation of high-spin nitrenes via radiolysis of crystalline azides is much superior to the photochemical technique in efficiency and may be of practical importance for the preparation of magnetically active organic materials

Science.gov (United States)

... of Viscous Liquids, Glasses, and Crystalline Materials Under Extremes of Pressure and Temperature ... Materials 9624724 ENG AZ U of Arizona Gervay Jacquelyn Synthesis of Novel Materials Utilizing Sialic ...

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The mechanical characteristics of semicrystalline materials are related to the proportion, size and structure of the crystalline phase. Studying isothermal crystallization is the first stage in determining what relations exist between structure and charac...

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The authors present differential scanning calorimetry (DSC) and in situ Moessbauer spectroscopy results for Metglas ribbons, to which different heat treatments were made. The Curie temperature of the amorphous phase is determined and the evolution of the magnetic field of this phase is studied as a function of temperature

International Nuclear Information System (INIS)

Single-crystalline cadmium selenide nanoparticles were obtained using high-temperature solution phase synthesis (HTSPS) synthesis. X-Ray powder diffraction and transmission electron microscopy were used to confirm the crystallinity and morphology of the resulting nanoparticles. To study the action of CdSe on antioxidant activity, we selected two biotechnological important strains of microalgae: cyanobacteria Spirulina platensis and red microalgae Porphyridium cruentum. In the case of Porphyridium cruentum, the obtained results demonstrated an increase in the productivity. For Spirulina platensis, the presence of the compound in the cultivating medium decreased the productivity of cyanobacteria.

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We have successfully grown single crystalline Formula Not Shown with the range of Formula Not Shown using the floating-zone method. All compounds show orthorhombic symmetry in this substitution range, but the difference between lattice constants a and b decreases with increasing Sr concentration and becomes almost zero at Formula Not Shown . Characteristic temperatures, which correspond to antiferromagnetic ordering and structural transition, decrease with increasing Sr concentration. The value of the magnetic susceptibility below 30K increases with increasing Sr concentration. The temperature dependence of the electrical resistivity revealed that Sr substitution significantly suppresses the highly anisotropic electric structure of Formula Not Shown .

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We have measured the frequency-dependent dielectric function of semi-crystalline polybutylene terephthalate (PBT) in the terahertz region between 100?GHz and approximately 2.8?THz. A characteristic band is observed around 2.38?THz. The intensity of this band is a good indicator of the degree of crystallinity of the different samples. A potential assignment of this band is proposed, based on the comparison with spectroscopic data of the structurally very similar polyethylene terephtalate (PET). Furthermore, the frequency-dependent index of refraction of PBT reveals more insight about the morphology and different thermal history of the samples under investigation.

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A novel process was proposed to synthesize nano Sb-encapsulated pyrolytic polyacrylonitrile composite for anode material in lithium secondary batteries. The preparation started with the dissolution of SbCl{sub 3} and polyacrylonitrile (PAN) in dimethylformamide (DMF) solution, followed by the addition of KBH{sub 4} to reduce Sb{sup 3+} in the solution. The Sb composite was obtained by pyrolysis of the Sb/PAN mixture that precipitated out when the DMF solution was added by plentiful water. The TEM analysis showed that about 100-200 nm Sb particles were embedded by the pyrolyzed PAN, which provided a conductive matrix to relieve the morphological change of Sb during electrochemical cycling. As-prepared composite presented good cycleability for lithium storage. The proposed process paves an effective way to prepare high performance alloy based composite anode materials for high performance lithium-ion batteries. (author)

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The single-electrode capacitance of a nano-porous carbon electrode used as an electric double layer capacitor was measured. The charged state of the electrolyte ion was discussed from the results. Single-electrode capacitance was not proportional to the specific surface area of the electrode. This implies that the whole surface of the electrode is not effective for the formation of an electric double layer. It is considered that edge orientation of the carbon structure would give a dominant contribution to capacitance. For measurements with aqueous solutions of various electrolytes, capacitance was about the same value for each salt compound. For aqueous acid solution, on the other hand, capacitance was twice to three times as large as that for salt compounds. This difference, however, became negligibly small if the concentration of electrolyte solution was lowered. Taking account of the hydrated ionic radius of each ion, it was considered that ions in salt ...

British Library Electronic Table of Contents (United Kingdom)

Ultra fine tungsten carbide and cobalt powders were milled by high energy planetary ball mill at different ball to powder weight ratios (BPR) to produce particles of WC-10wt%Co hard metal in nanometer scale size. Microstructural characterizations by TEM show that the particle size of tungsten carbide was achieved to 32nm after milling at 15 BPR during 10h. In order to reduce the WC grain growth during the sintering process, tantalum carbide was added to the hard metal as a WC grain growth inhibitor. The nano hard metal powders were compacted at 200MPa pressure and sintered at 1370-1450degreeC temperatures in a high purity hydrogen atmosphere. The results show that the addition of 0.6wt% of TaC improves the hardness and fracture toughness from 1493 HV30 and 11.8MPam (for TaC free sample) to...

Science.gov (United States)

Hybridization and thermal evolution of the Ni+C{sub 60} composites, deposited on Si(001) at room temperature, were studied using Scanning Electron Microscopy, {mu}-Raman spectroscopy and Rutherford Backscattering. As-deposited, the hybrid films exhibited a granular nano-structure with Ni nano-particles encapsulated in C{sub 60} polymerized rinds. The Ni and C (C{sub 60}) distributions in a top layer were found homogeneous with a stable Ni/C (C{sub 60}) ratio; in the larger depth the distributions were inhomogeneous and their ratio dramatically varied. At elevated temperatures, all structural parameters were changed. In the subsurface layer Ni- and C (C{sub 60})-rich zones were formed (due to the induced phase separation), C{sub 60}-molecules decayed and their fragments were transformed into amorphous carbon (a-C). The free volume distribution of the stressed hybrid matter was analyzed by the Hg marker that (in a form of vapors) in-diffused in ...

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The authors report on the nano-fabrication of GaN/AlGaN device structures using focused ion beam (FIB) etching, illustrated on a GaN/AlGaN heterostructure field effect transistor (HFET). Pillars as small as 20nm to 300nm in diameter were fabricated from the GaN/AlGaN HFET. Micro-photoluminescence and UV micro-Raman maps were recorded from the FIB-etched pattern to assess its material quality. Photoluminescence was detected from 300nm-size GaN/AlGaN HFET pillars, i.e., from the AlGaN as well as the GaN layers in the device structure, despite the induced etch damage. Properties of the GaN and the AlGaN layers in the FIB-etched areas were mapped using UV Micro-Raman spectroscopy. Damage introduced by FIB-etching was assessed. The fabricated nanometer-size GaN/AlGaN structures were found to be of good quality. The results demonstrate the potential of FIB-etching for the nano-fabrication of III-V nitride devices.

International Nuclear Information System (INIS)

Direct electrochemistry and electrocatalysis of catalase (Cat) was studied based on a nano-composite film consisting of amine functionalized graphene and gold nanoparticles (AuNPs) modified glassy carbon electrode. Graphene was synthesized chemically by Hummers and Offeman method and then was functionalized with amino groups via chemical modification of carboxyl groups introduced on the graphene surface. The nano-composite film showed an obvious promotion of the direct electron transfer between Cat and the underlying electrode, which attributed to the synergistic effect of graphene-NH2 and AuNPs. The resultant bioelectrode retained its biocatalytic activity and offered fast and sensitive H2O2 quantification. Under the optimized experimental conditions, hydrogen peroxide was detected in the concentration range from 0.3 to 600 ?M with a detection limit of 50 nM at S/N = 3. The biosensor exhibited some advantages, such as short time respond (2 s), ...

British Library Electronic Table of Contents (United Kingdom)

A type of Si3N4-based nanocomposites ceramic cutting tool material was prepared by the addition of nano-scale Si3N4W whisker and nano-scale TiN particle. Cutting performance of the Si3N4/Si3N4W/TiN nanocomposite ceramic tool in machining of cast iron was investigated in comparison with a commercial sialon ceramic tool, and the tool wear mechanism was studied. The two types of cutting tools have similar cutting performance at relatively low cutting parameters, while Si3N4/Si3N4W/TiN nanocomposite tool exhibits a better wear resistance than sialon tool at the relatively high cutting parameters. The wear of sialon ceramic cutting tool is dominated by the plastic deformation, abrasive action, microcracking, pullout of grains and chemical action at the higher cutting parameters. The higher mech...

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An efficient method of hydrogen storage in nano-porous carbons is its reversible sorption by electrochemical decomposition of a KOH water solution according to the following equation: C + xH{sub 2}O + xe{sup -} {yields} (CH{sub x}) + xOH{sup -} where (CH{sub x}) stands for the hydrogen inserted into the nano-porous carbon during charging and oxidized during discharging. Although various carbon materials have been investigated as hydrogen adsorbents, the information about the storage mechanism as well as the nature of the hydrogen/carbon interaction is still not sufficient. In order to extend the understanding of the process, carbon samples charged electrochemically were investigated by temperature programmed desorption (TPD). The nature of the hydrogen/carbon interaction was studied by electrochemical analysis at different temperatures. The TPD experiments consist of heating the samples from room temperature to 950 C and of quantitative ...

International Nuclear Information System (INIS)

Atmospheric pressure plasma enhanced chemical vapour deposition system is built. The electrical and optical characteristics of the APPECVD system is given. The system is used to deposit conductive polymers and nano composites onto glass and metal surfaces. The morphological, optical, chemical and electrical characteristics of deposited surfaces are investigated using SEM, AFM four probe deposition purposes. The photovoltaic applications of plasma deposited polymers and nonconsumption are compared with deposited with electrochemical methods show different results. The electrical, chemical and morphological structures of the samples will be given.

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The magnetoresistance in an FeNi submicron-structure comprising two wires of 80 and 200 nm in width connected in series was measured at 77 K. When the external magnetic field was applied parallel to the wire axis, two switching fields corresponding to the distinct coercive force of the two wires were observed. When the external magnetic field was applied at an angle of {theta}>30 deg. to the wire axis one switching field was observed, indicating simultaneous magnetization reversal in both wires. This indicates that the domain-wall trapping around the joint can be controlled systematically in terms of the direction of the external magnetic field.

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The ZnO nanorods were used as a template to fabricate nickel nanoclusters by electrodeposition. The ZnO nanorod arrays act as a nano-semiconductor electrode for depositing metallic and magnetic nickel nanoclusters. The growth sites of Ni nanoclusters could be controlled by adjusting the applied potential. Under -1.15 V the Ni nanoclusters could be grown on the tips of ZnO nanorods. On increasing the potential to be more negative the ZnO nanorods were covered by Ni nanoclusters. The magnetic properties of the electrodeposited Ni nanoclusters also evolved with the applied potentials.

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Most of the investigations have a theoretical sustenance based on molecular simulation. The area of application of molecular simulation is very wide, in the Materials Technology Department assigned to the Applied Sciences Management have been treated problems about metallic nano structures, glasses, interfaces, and molecules, to sustain and to explain some of the experimental results. Energy calculations are carried out to determine minimum energy structures, for later on to carry out calculations of some of their properties; as well as the images simulation of Electron microscopy and X-ray diffraction. (Author)

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The oxide colloidal route, developed in the laboratory for mono-metallic catalysts, consists in preparing a metallic oxide hydro-sol which leads to the supported catalyst after deposition onto a support and an activation stage. In this work, this method has been adapted to the preparation of alumina supported bimetallic Pd-Sn catalysts to determine its interest for the control of the properties of the bimetallic phase (size, composition and structure). In the preliminary study concerning tin oxide sols, SnO{sub 2} (size=2,3 nm) and Sn{sub 6}O{sub 4}(OH){sub 4} (size = 25 nm) nano-particles were synthesized by neutralization respectively for tin(IV) and tin(H). The control through the pH of the aggregation of the PdO and SnO{sub 2} particles revealed that increasing oxide solubility promotes integral re-dispersion of the oxide particles. To synthesize oxide bimetallic sols, three strategies were defined. Copolymerization (formation of a mixed oxide ...

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A major factor for the achievement of the desirable performance, efficiency and lifetime of flexible organic electronic devices is the optimization of the encapsulation layers that protect the device active layers by atmospheric gas molecule permeation. The active layers consisted of small molecule and/or polymer organic semiconductors as well as the organic conductors need to be encapsulated into a transparent medium that will provide the necessary protection and maintain their charge generation and transport characteristics. The encapsulation layers are generally consisted of inorganic thin films (silicon oxide-SiO{sub x} and aluminium oxide-AlO{sub x}) deposited onto the polymeric substrates, such as PolyEthylene Terephthalate (PET). In this work, in situ and real-time Spectroscopic Ellipsometry in the ultraviolet spectral region has been implemented in order to investigate the growth of inorganic SiO{sub x} and AlO{sub x} nano-layers onto PET flexible polymeric ...

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Sulfated zirconia (SO4-ZrO2) catalysts, prepared with three different sulfur loading contents (0.75%, 1.8% and 2.5%) at two calcination temperatures (500degreeC and 700degreeC), were tested for use in the transesterification of purified palm oil (PPO) and the esterification of palm fatty acid (PFA) in near-critical and super-critical methanol. Techniques including BET, XRD, NH3- and CO2-TPD revealed that the sulfur content and calcination temperature strongly affects the catalyst base-acid site, specific surface area, average pore size, phase structure, and thus the catalytic reactivity. The most suitable sulfur loading content was found to be 1.8% and the optimum calcination temperature 500degreeC. The results show that the use of SO4-ZrO2 reduces esterification reaction times, the amount...

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A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). We investigated mechanical properties, such as the hardness and Young's modulus, of ceramic specimens after superplastic deformation. The tested material was 3Y-TZP (3mol% Yttria stabilized Tetragonal Zirconia Polycrystal) which is one of the representative superplastic ceramics. The properties were measured by a microindentation method. We also studied the relationship between crystal microstructures and the mechanical properties of deformed 3Y-TZP by scanning electron microscope (SEM). The indentation test showed that the mechanical properties of the specimens were reduced to about 1/2 by 30% deformation and to about 1/4 by 150% deformation. The SEM images showed that average grain size and deviation of grain size of each specimen ...

International Nuclear Information System (INIS)

A family of sealant materials has been developed for use in the solid oxide fuel cell (SOFC) and in other applications in the temperature range of 800 endash 1000 degree C. These materials are based on glasses and glass-ceramics in the SrO endash La_2O_3 endash Al_2O_3 endash B_2O_3 endash SiO_2 system. The coefficients of thermal expansion (CTE) for these materials are in the range of 8 endash 13x10"-"6/degree C, a good match with those of the SOFC components. These sealant materials bond well with the ceramics of the SOFC and, more importantly, form bonds that can be thermally cycled without failure. At the fuel cell operating temperature, the sealants have viscosities in the range of 10"4-10"6 Pa-s, which allow them to tolerate a CTE mismatch of about 20% among the bonded substrates. The gas tightness of a sample seal was demonstrated in a simple zirconia-based oxygen concentration cell. copyright 1996 Materials Research Society.

International Nuclear Information System (INIS)

This paper reports on an experimental investigation of premixed methane/air combustion stabilized within a reticulated partially stabilized zirconia foam burner that was performed. A flame holder was used to extend the stability range to allow a stable flame to be maintained for a variety of flow rate and equivalence ratio combinations. The stability range, temperature distributions, and emissions were examined over a range of equivalence ratios and flow rates. The flame was found to be axisymmetric for all conditions in which the reactants were sufficiently well mixed and the flow distribution was sufficiently uniform. Burning speeds were measured that were well in excess of the laminar flame speed. The axial temperature distribution (measured around the burner annulus) in the postflame zone was found to be relatively insensitive to flow rate but dependent upon the burner core length. Very low concentrations of NO_x were found for fuel/air equivalence ratios of ...

International Nuclear Information System (INIS)

BaTiO_3 compacts, when fluxed with < 2 vol% of a complex borate glass phase, were sintered to near theoretical density at temperatures < 1175 degrees C in 2 h. Microstructural analysis showed a uniform grain size < 1.0 #mu#m with 0.75 wt% ZrO_2 added to the flux phase as a grain growth inhibitor. TEM analysis revealed a microcrystalline grain-boundary phase with the ZrO_2 resident along the grain boundaries. These samples displayed an essentially flat dielectric profile, low dissipation factors (< 2%) over the range 25 degrees to 125 degrees C, a near linear dependence (#approx# #+-# 15%) between 25 degrees and - 55 degrees C, and significantly increased voltage stability. X-ray diffraction analysis of these small-grained materials indicates a suppression of the tetragonal structure toward a more cubic modification.

Energy Technology Data Exchange (ETDEWEB)

The feasibility of using hydrogen as the sole fuel in a direct injection diesel engine was investigated. An air cooled single cylinder Lister ST1 diesel engine was modified to operate as a low-heat-rejection engine for this study. Partially stabilized zirconia ceramic parts were used to shield the combustion space of the engine. Using a compression ratio of 17.9:1 and motoring the test engine at 21000 rpm, a maximum compression temperature of approximately 900 K was achieved. Under these operating conditions, all lubricants tested were found to burn. Lowering the speed to 1450 rpm and the compression ratio to 17.1, lubricant combustion and hot spots were successfully eliminated. The maximum compression temperature, when compression ignition of hydrogen was tried, was in the 800 K range. The corresponding ceramic surface temperature was estimated to reach 600-700 K. Only sporadic compression ignition of hydrogen was achievable. (author).

Energy Technology Data Exchange (ETDEWEB)

The crystallization dynamics of Nylon 66/Nylon 48 blends, the crystalline/crystalline polymer blend, was analyzed by differential scanning calorimetry (DSC) under isothermal conditions. The equilibrium melting temperature (T{sub m}{sup 0}), crystal growth rate (G) and the nucleation rate (N) depended on both the degree of supercooling ({delta}T) and the blend fraction (phi). The {delta}T/T{sub m}{sup 0} values obtained at the fixed G, which corresponded to the chemical potential different between molecules in the liquid and the crystal states, and the surface free energy parameters evaluated from G and N depended on phi for blends. The results suggested that Nylon 66/Nylon 48 blends are miscible in all blend fractions. The result agrees with the intermolecular interaction parameter ({chi}) obtained from T{sub m}{sup 0} depression. Infrared spectroscopic and X-ray diffraction data indicated that the hydrogen bond became weak and the crystalline ...

Energy Technology Data Exchange (ETDEWEB)

We investigate a new texturization technique for crystalline silicon solar cells with sodium carbonate (Na{sub 2}CO{sub 3}) solutions. We show the dependence of the hemispherical surface reflectance on solution temperature, the etching time and the Na{sub 2}CO{sub 3} concentration. Furthermore, we investigate what element in Na{sub 2}CO{sub 3} solution influences the texturing for reducing the texturing time. As a result of experiments, we find it possible to get low reflectance in a shorter texturing time by the addition of NaHCO{sub 3}. The size of texture becomes smaller by the addition of NaHCO{sub 3} but the etching rate does not change. We conclude carbonic ion and/or its compound seems to play an important role as the initiator of pyramidal structure. This texturing method is cost effective because there is no need of expensive IPA, and the surface reflectance is reduced sufficiently in a short time. This method is promising for a large-scale production of ...

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Transient enhanced diffusion of phosphorus in silicon has been investigated for implants below and above the threshold for a complete amorphization. Rapid thermal processes (electron beam) and conventional furnaces have been used for the annealing. In the case of implants below amorphization, a strong enhanced diffusion, proportional to the amount of damage produced, has been observed. The extent of the phenomenon is practically independent of the damage depth position. In contrast to this, the formation of extended defects at the original amorphous-crystalline interface makes the diffusivity strongly dependent on depth in the case of post-amorphized samples. No enhanced diffusion effect is observed if the dopant is confined in the amorphous layer, while a remarkable increase in the diffusivity is detected for the dopant located in the crystalline region beyond the amorphous-crystalline interface. Damage distribution after ...

Energy Technology Data Exchange (ETDEWEB)

The physical properties of polymer blends consisting of one or more crystallizable components are affected by the microstructure of these materials. In particular, the degree of crystallinity can be influenced by processing parameters, and the crystallinity, as well as the phase distribution, may vary as a function of depth through an injection molded part Conventional x-ray diffraction techniques can provide information regarding both phase composition and degree of crystallinity, but, because of the relative transparency of these materials to wavelengths generally available in the laboratory, these techniques provide information representative of only the bulk. By employing parallel beam optics at varying grazing incidence angles, the x-ray sampling depth can be varied without loss of resolution. This technique can be used to vary the effective analysis depth from the top several hundred angstroms for low razing incidence ...

British Library Electronic Table of Contents (United Kingdom)

PurposeTo evaluate the effect of vitrectomy timing on outcomes for patients with crystalline retained lens fragments receiving vitrectomy 3+ days after cataract surgery. DesignSystematic review and meta-analysis of retrospective interventional cases series. MethodsSearches of MEDLINE (English, 1/1/85 through 7/30/2010) and article reference lists. Articles were screened for patients with crystalline retained lens fragments after surgery for age-related cataracts, discussion of vitrectomy timing, and, for the meta-analysis, patient totals for at least 1 outcome and multiple time periods, 10+ patients, and mean follow-up ?3 months. Outcomes included visual acuity, retinal detachment, increased intraocular pressure, intraocular infection/inflammation, cystoid macular edema, and corneal...

British Library Electronic Table of Contents (United Kingdom)

This paper presents studies carried out on tin-doped indium sulfide films prepared using Chemical Spray Pyrolysis (CSP) technique. Effect of both in-situ and ex-situ doping were analyzed. Ex-situ doping was done by thermal diffusion, which was realized by annealing Sn/In2S3 bilayer films. In-situ doping was accomplished by introducing Sn into the spray solution by using SnCl45H2O. Interestingly, it was noted that by ex-situ doping, conductivity of the sample enhanced considerably without affecting any of the physical properties such as crystallinity or band gap. Analysis also showed that higher percentage of doping resulted in samples with low crystallinity and negative photosensitivity. In-situ doping resulted in amorphous films. In contrast to ex-situ doping, `in- situ doping' resulted i...

International Nuclear Information System (INIS)

In this study the results of mathematical simulation and experimental research of texture transition in stress assisted shear phase transformations are discussed. The orientation distribution function (ODF) calculation model to the any type crystalline lattice symmetry materials has been suggested. By crystalline lattice symmetry analysis this computer program determines necessary amount of the initial experimental data. The experimental verification supports this model well. The ODF calculation model after shear phase transformation with equal use of all possible variants of orientation relationship or with various degrees of variant selection worked out. In this study the experimental and calculating data of the direct and reversal shear transformations #alpha# <=> #gamma# in Fe-alloys and B2 <=> B19' in Ti-Ni alloys are discussed. The stress assisted shear phase transformation model and computer program to calculate ODF after ...

International Nuclear Information System (INIS)

The transformation from the as-quenched amorphous to the crystalline state in Fe_7_8B_1_3Si_9 alloy has been investigated using a new-type neutron diffractometer. The time resolved diffraction patterns clearly show that this alloy crystallizes into FeSi alloy and Fe_2B in that order. The time evolution of these crystalline phases can be analyzed by the Kolmogorov-Johnson-Mehl-Avrami equation with the exponent of about 2.5 over a wide temperature range. This suggests that the crystallization occurs by the diffusion-controlled growth with a constant nucleation rate. The scaling behavior in the crystallization kinetics is also discussed. (author).

Science.gov (United States)

Within the framework of the cluster approach and the semiempirical SCF MO LCAO method in the CNDO/BW valence approximation, possible pathways have been compared for the dehydroxylation of aluminosilicate systems. It has been shown that dehydroxylation as a result of splitting of a water molecule from an acidic bridge hydroxyl group and a more basic terminal group Al-OH is the most energyfavorable. Apparently, such a dehydroxylation pathway is primarily characteristic for amorphous aluminosilicates. Typical of crystalline aluminosilicates at moderate heat-treating temperature is dehydroxylation through splitting of a water molecule from an acidic bridge hydroxyl group and a neutral Si-OH group; at higher temperatures, there is a possible pathway of dehydroxylation of highsilica zeolites as a result of condensation of two acidic surface hydroxyls.

British Library Electronic Table of Contents (United Kingdom)

A new series of anatase TiO2 hollow structures were prepared by a facile hydrothermal process. When the hydrothermal time was increased from 20min to 72h, the resulting TiO2 solid spheres gradually transformed into TiO2 hollow spheres with higher surface crystallinity and exposed {001} facets. The as-prepared TiO2-72h sample exhibited the highest activity comparing to other TiO2-based samples and commercial product Degussa P-25 towards the selective photocatalytic oxidation of toluene to benzaldehyde. Such great photocatalytic performance was mainly attributed to enhanced UV-adsorption and better charge separation efficiency due to higher surface crystallinity of TiO2-72h.

Energy Technology Data Exchange (ETDEWEB)

Single-crystalline CeRh{sub 2}Si{sub 2} and CePd{sub 2}Si{sub 2} were grown by the Czochralsky pulling method and the temperature dependence of magnetic susceptibility was investigated. The crystalline electric field (CEF) states in each compound were determined by considering the tetragonal CEF Hamiltonian with mean-field approximation. Interactions between Ce{sup 3+} ion and the surrounding ligands in CeRh{sub 2}Si{sub 2} turned out to be strong and highly anisotropic in comparison to CePd{sub 2}Si{sub 2}. (orig.) 10 refs.

British Library Electronic Table of Contents (United Kingdom)

Commercial polyolefin, such as poly(propylene), are widely used because of their easy processing and their excellent mechanical and thermal properties. Although their recycling is well established, the mechanical and thermal properties of the recycled waste poly(propylene)(WPP) are normally lower than those of the virgin material. The introduction of talc can improve the toughness, without compromising the processability and recycling capabilities. However, the thermal properties of these blends should be assessed to limit degradation during recycling. The effect of gamma radiation on the thermal and mechanical properties of WPP/High Crystallinity Poly(propylene)/Talc was studied. TGA, DSC, and electrical conductivity performed the characterization of WPP composites. Mechanical properties ...

International Nuclear Information System (INIS)

N-type crystalline Si (100) implanted with 5 keV B ions was subsequently irradiated with MeV Si, O and F ions. The B atom profiles were measured by means of secondary ion mass spectrometer after the treatment of rapid thermal annealing. The results show that the transient enhanced diffusion of B atoms is effectively limited by the post-implantation of high energy ions at high dose. At the same irradiation conditions, it is found that the existence of a SiO_2 layer in the near surface of Si is even more effective in suppressing the transient enhanced diffusion of the doped B atoms. The results are qualitatively discussed in combination with the analyses of RBS/c measurements and calculation of the DICADA code

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The carbonate rocks of the Lower Ordovician Majiagou Formation represent important hydrocarbon reservoirs in the Ordos basin in the western part of the North China plate. Cores and thin sections from more than 60 wells were examined. The main reservoir in the Majiagou Formation consists of fine crystalline dolomite, which was altered by meteoric water during an extended subaerial exposure. Three phreatic zones have been identified in the Majiagou Formation in the northern part of the basin. Oxygen isotopes and fluid inclusion microthermometry data indicates that the porosity developed during the early karst event was considerably reduced by the late-stage, coarse crystalline calcite cements that appear to be related to hydrothermal fluids during deep burial. It was concluded that the main factors that determine the porosity and permeability of these carbonate reservoirs are dolomitization, karstification, and calcite cementation.

British Library Electronic Table of Contents (United Kingdom)

Transparency is essential for normal corneal function. Recent studies suggest that corneal cells express high levels of so-called corneal crystallins, such as aldehyde dehydrogenase (ALDH) and transketolase (TKT) that contribute to maintaining cellular transparency. Stromal injury leads to the appearance of repair phenotype keratocytes, the corneal fibroblast and myofibroblast. Previous studies on keratocytes from species such as bovine and rabbit indicate that the transformation from the normal to repair phenotype is accompanied by a loss of corneal crystallin expression, which may be associated with loss of cellular transparency. Here we investigated if a similar loss occurs with human keratocyte repair phenotypes. Human corneal epithelial cells were collected by scraping and keratocytes...

International Nuclear Information System (INIS)

The transient enhanced diffusion in crystalline silicon implanted with dopants ad followed by high temperature annealing to activate the dopants is introduced. The physical mechanisms of transient enhanced dopant diffusion are then reviewed together with a short introduction to the proposed suppressing methods. Finally, the perspectives with using high energy heavy ions in this field are briefly discussed

Energy Technology Data Exchange (ETDEWEB)

Recent developments in design and production of thermal neutron detectors based on a crystalline Si diode coupled to a Gd converter are reviewed. The most significant results of neutron test measurements carried out on prototype systems and pointing out the performances of the device are reported. Progress through various detection schemes and technological solutions for the production of a real time neutron counter for routine operation are outlined.

British Library Electronic Table of Contents (United Kingdom)

The catalytic performance of alkaline-treated zeolite H-ZSM-5 in the conversion of methanol to gasoline has been studied. After treatment with 0.20M NaOH, the total conversion capacity increased by a factor of 3.3, and the selectivity towards the gasoline fraction increased by a factor of 1.7. Physical characterization indicated the formation of mesopores and improved crystallinity.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a catalyst comprising: (a) a non-zeolitic inorganic oxide matrix, and (b) an ultrastable Y-type crystalline zeolite, the ziolite having been pretreated by contacting the zeolite with a phosphorus compound selected from the group consisting of phosphoric acid, phosphorous acid, a salt of phosphoric acid, a salt of phosphorous acid, and mixtures thereof for a time sufficient to composite an effective amount of phosphorus with the zeolite.

Energy Technology Data Exchange (ETDEWEB)

Magnetic field, thickness and magnetic forming effect on general mode and quantitative parameters of the domain structure (DS) of ferrite-garnet (EuEr)/sub 3/(FeGa)/sub 5/O/sub 12/ monocrystalline plates (111) is investigated. Field interval of circle (cone) and ring domain stability is determined. It is shown that DS of ferrite-garnet crystals with uniaxial an6sotropy has some peculiarities, that can be explained by cubic anisotropy effect.

International Nuclear Information System (INIS)

The doping of deuterated polyparaphenylene [C_6D_4]sub(n) with AsF_5 has been investigated by real time neutron diffractometry at 100, 400 and 820 mbar AsF_5 pressure. The reaction appears to be diffusion controlled. Evidence for one doped phase with partial crystalline order was obtained. Structural considerations suggest two polymer chains plus one dopant ''string'' as the repetitive unit. (Auth.).

Science.gov (United States)

The heterogeneous processing of atmospheric aerosols by reaction with nitrogen oxides results in the formation of particulate and adsorbed nitrates. The water content of these hygroscopic nitrate aerosols and consequently the nitrate ion concentration depend on relative humidity, which can impact the physicochemical properties of these aerosols. This report focuses on the 310 nm photolysis of aqueous sodium and calcium nitrate solutions at pH 4 over a wide concentration range of nitrate ion concentrations representative of atmospheric aerosols. In particular, the quantum yield (phi) of nitrite formation was measured and found to significantly decrease at high concentrations of nitrate for Ca(NO(3))(2). In particular, phi for Ca(NO(3))(2) was found to have a maximum value of (7.8 +/- 0.1) x 10(-3) for nitrate ion solution concentrations near one molal, with the smallest quantum yield for the highest concentration solution above 14 m nitrate ion, phi = (2.3 +/- 2.0) x 10(-4). The effect ...

British Library Electronic Table of Contents (United Kingdom)

Nano- and microstructured surfaces are known to impact on the binding and differentiation of cells, but the detailed basic understanding of the underlying regulatory mechanisms is still scarce, which impedes the rational design of smart biomaterials. Towards a comprehensive analysis of the interplay between topographical parameters such as feature design and lateral and vertical dimensions we here report on a combinatorial screening approach, BioSurface Structure Array (BSSA) of test squares each with a distinct topography. Using such BSSA libraries of 504 topographically distinct surface structures, we have identified combinations of size, gap and height of structures which enhance mineralization as well as the expression of osteogenic markers of a preosteoblastic murine cell line. This g...

Energy Technology Data Exchange (ETDEWEB)

An efficient method of hydrogen storage in nano-porous carbons is its reversible sorption by electrochemical decomposition of a KOH water solution [1-3] according to the following equation: C + xH{sub 2}O + xe{sup -} {yields} (CH{sub x}) + xOH{sup -} where (CH{sub x}) stands for the hydrogen inserted into the nano-porous carbon during charging and oxidized during discharging. Although various carbon materials have been investigated as hydrogen adsorbents, the information about the storage mechanism as well as the nature of the hydrogen/carbon interaction is still not sufficient. In order to extend the understanding of the process, carbon samples charged electrochemically were investigated by temperature programmed desorpt(TPD). The nature of the hydrogen/carbon interaction was studied by electrochemical analysis at different temperatures. The TPD experiments consist of heating the samples from room temperature to 950 C and of quantitative ...

British Library Electronic Table of Contents (United Kingdom)

In this paper, we report an optical fiber sensor for measuring temperature based on bimetallic concept. The sensor is designed by following the basic principle of Fabry-Perot interferometer and theoretical detail of the sensor has been outlined here with a numerical study. An important feature of the proposed sensor is that the fabrication will be done on a commercial multimode optical fiber. The Micro-Electro-Mechanical Systems (MEMS) based fabrication process could be performed directly on a multimode optical fiber end face which will eliminate the need for adhesive in packaging. The sensor could be fabricated as sensor arrays for micro level applications. The potential application of the proposed optical sensor includes biomedical applications, nano research, microfluidics, and other ME...

CERN Document Server

We report on the magnetic hyperthermia properties of chemically synthesized ferromagnetic 11 and 16 nm Fe(0) nanoparticles of cubic shape displaying the saturation magnetization of bulk iron. The specific absorption rate measured on 16 nm nanocubes is 1690+-160 W/g at 300 kHz and 66 mT. This corresponds to specific losses-per-cycle of 5.6 mJ/g, largely exceeding the ones reported in other systems. A way to quantify the degree of optimization of any system with respect to hyperthermia applications is proposed. Applied here, this method shows that our nanoparticles are not fully optimized, probably due to the strong influence of magnetic interactions on their magnetic response. Once protected from oxidation and further optimized, such nano-objects could constitute efficient magnetic cores for biomedical applications requiring very large heating power.

British Library Electronic Table of Contents (United Kingdom)

Focused Ion Beam (FIB) technology has become an indispensable enabling tool for micro nano fabrications. One important application is to use FIB for patterning conducting nanowires of metals down to a few tens of nanometre for applications such as interconnects, heaters and temperature nanosensors. A series of experiments on Au nanowires fabricated by FIB on SixNy membrane show that nanowires with width 50nm have structural instabilities. These are liquid like and first show-up as undulations in nanowire width with clearly defined wave lengths. For smaller widths (20nm) the instabilities grow and the wires eventually break-up into spherical balls. Further experiments show that the nanowires can be made stable to smaller widths by the use of a Cr underlayer to enhance surface wetting. The o...

British Library Electronic Table of Contents (United Kingdom)

This study addresses the solar thermal decomposition of natural gas for the co-production of hydrogen, as well as Carbon Black as a high-value nano-material, with the bonus of zero CO2 emissions. The work focused on the development of a medium-scale solar reactor (10kW) based on the concept of indirect heating. The solar reactor is composed of a cubic cavity receiver (20cm side), which absorbs concentrated solar irradiation through a quartz window via a 9cm-diameter aperture. The reacting gas flows inside four graphite tubular reaction zones that are settled vertically inside the cavity. Experimental results were as follows: methane conversion and hydrogen yield of up to 98% and 90%, respectively, were achieved at 1770K, and acetylene was the most important by-product, with a mole fraction...

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)

The energy levels scheme of octahedrally coordinated Ni2+ ion in single crystal, powder nano-single crystal, ceramics and glass-ceramics of MgGa2O4 host matrix, has been calculated in the exchange charge model of crystal field. The parameters of the crystal field acting on the Ni2+ ion are calculated from the crystal structure data, after optimization of the geometry of the system. The energy level schemes have been calculated by diagonalization of the crystal field Hamiltonian of this system. The obtained results were compared with experimental data; a good agreement were demonstrated, which confirm the validity of the model and used method.

British Library Electronic Table of Contents (United Kingdom)

SBA-15 supported nano-scaled copper oxide was synthesized by impregnation method via ultrasonic-assisted route. The removal test from gas mixture containing 0.1?vol.% hydrogen sulfide was carried out over this material at atmospheric conditions. The effects of the chemical nature of copper oxide and the textural properties of the material on removal capacity were studied. The materials before and after the removal test were analyzed by nitrogen adsorption, X-ray diffraction, Transmission Electron Microscope, X-ray photoelectron Spectroscopy, Fourier Transform Infrared Spectrometer and Inductive Coupled Plasma. The results showed that copper species are located predominantly in mesopore channels, existing as copper oxide nanoparticles. Mesopores are active sites for removal reaction. The ou...

Science.gov (United States)

Herpes simplex virus type-1 (HSV-1) entry into target cell is initiated by the ionic interactions between positively charged viral envelop glycoproteins and a negatively charged cell surface heparan sulfate (HS). This first step involves the induction of HS-rich filopodia-like structures on the cell surface that facilitate viral transport during cell entry. Targeting this initial first step in HSV-1 pathogenesis, we generated different zinc oxide (ZnO) micro-nano structures (MNSs) that were capped with multiple nanoscopic spikes mimicking cell induced filopodia. These MNSs were predicted to target the virus to compete for its binding to cellular HS through their partially negatively charged oxygen vacancies on their nanoscopic spikes, to affect viral entry and subsequent spread. Our results demonstrate that the partially negatively charged ZnO-MNSs efficiently trap the virions via a novel virostatic mechanism rendering them unable to enter into human corneal ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this memo is to give an update on our work on ceramic laser materials--feasibility proposal 04-FS-006. Transparent ceramic materials have several major advantages over single crystals in laser applications including, ease and robustness of manufacturing, large apertures, design flexibility, fracture toughness, high activator concentrations, uniformity of composition, no residual stress, and others discussed in the proposal. After a decade of working on making transparent YAG:Nd in 1995 Japanese workers demonstrated samples for the first time that performed as well in lasers as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. The highlights and executive summary of our work to date are: (1) Ordered a slab of transparent YAG:Nd from Konoshima Chemical Co. for ...

International Nuclear Information System (INIS)

Colorectal carcinoma is a highly prevalent and common cause of cancer in Taiwan. There is still no available cure for this malignant disease. To address this issue, we applied the multimodality of molecular imaging to explore the efficacy of diagnostic and therapeutic nanoradiopharmaceuticals in an animal model of human colorectal adenocarcinoma [colorectal cancer (CRC)] that stably expresses luciferase (luc) as a reporter. In this study, an in vivo therapeutic efficacy evaluation of dual-nanoliposome (100 nm in diameter) encaged vinorelbine (VNB) and "1"1"1In-oxine on HT-29/luc mouse xenografts was carried out. HT-29/luc tumor cells were transplanted subcutaneously into male SCID mice. Multimodality of molecular imaging approaches including bioluminescence imaging (BLI), gamma scintigraphy, whole-body autoradiography (WBAR) and in vivo tumor growth tracing, histopathology and biochemistry/hematology analyses were applied on xenografted SCID mice to study the treatments with 6% ...

Energy Technology Data Exchange (ETDEWEB)

The objective of the first project period is to: make a study into materials suitable for the non-premix radiant burners (NPRB); choose the materials for the construction; make proposals for the design of the NPRB; test the different proposals with a CFD-model. In pursuit of finding a suitable material it is necessary first to estimate the maximum temperature that will occur in the burner. It has been estimated that the maximum adiabatic flame temperature will be about 2400-2500 K. The maximum temperature in the burner will of course never reach this level. A more realistic temperature was estimated to 2100-2300 K. The final choice was made after having contacted some of the leading producers. It was possible to find one producer that could produce burners of one of the suggested materials, zirconia. Several construction ideas for the NPRB have been discussed and some of them tested with a CFD-model. The proposed burner concept has been modified in order to obtain ...

Energy Technology Data Exchange (ETDEWEB)

In this study, the bend properties of the single-crystalline molybdenum brazed by using Mo-40%Ru alloys containing boron of 1-6 mass%Ru alloy for the improvement of the joint strength was determined. (orig.) [Deutsch] Durchgefuehrt wurde die Herstellung von Verbindungen aus einkristallinem Molybdaen. Hierbei kamen Mo-40%Ru-Legierungen mit 1 bis 6 Gew.-% Bor als Lotmaterialien zum Einsatz. Festigkeit und Duktilitaet der Verbindungen wurden mittels 3-Punkt-Biegepruefung bei Raumtemperatur und unter fluessigem Stickstoff ermittelt. Die Bruchflaechen der Proben wurden mit Hilfe eines Rasterelektronenmikroskopes untersucht. Die Ergebnisse lassen sich wie folgt zusammenfassen: Der optimale Borgehalt bezueglich Festigkeit und Duktilitaet der geloeteten Verbindung liegt bei 2 Gew.-%. Die entsprechende Probe hat bei einem Biegewinkel von 100 bei Raumtemperatur nicht versagt. Auch unter fluessigem Stickstoff zeigte diese Probe eine Festigkeit in der Groessenordnung des ...

International Nuclear Information System (INIS)

The amorphization of a quenched sample of the GaSb-II high-pressure phase was studied at ambient pressure by real-time neutron diffraction in the course of the sample heating from 100 K to room temperature at a rate of 0.4 K min-1. The transformation to the amorphous state begins at 140 K and is completed near room temperature. The ?-Sn type structure was shown to represent only the mean lattice of the high-pressure GaSb-II phase. The superstructure of this phase widely varied with temperature and is caused by the ordered displacement of atoms. The temperature range of the metastable crystalline phase relaxation is divided into three intervals according to the temperature dependence of the tetragonality ratio (c/a). At the boundaries of these temperature intervals, i.e. temperatures T = 170 and 230 K, two second-order phase transitions are observed. Anomalous heat and volumetric effects were observed earlier by means of calorimetry and dilatometry in the same ...

Energy Technology Data Exchange (ETDEWEB)

The paper gives results of a study to identify active sites and surface functional groups that may contribute to the absorption of elemental mercury (Hg) by relatively inexpensive calcium (Ca)-based sorbents. The study investigated the formation of chlorine (Cl) sites in CA-based sorbents as well as their role and reactivity in the absorption of Hg. HCl-exposed calcium sulfate dihydrate (gypsum) exhibited a superior Hg sorption capability. Crystalline water molecules on the surface of the gypsum were confirmed to contribute indirectly to Hg uptake. These surface molecules may have absorbed HC1 through hydrogen bond formation between an oxygen atom of a crystalline water molecule and a hydrogen atom of an HCl molecule. Two adjacent, physically absorbed HCl molecules could then trap an Hg molecule through formation of a mercuric-chloride-like molecule. Significant correlations between Cl and Hg uptake by gypsum were noted.

Energy Technology Data Exchange (ETDEWEB)

This paper describes inorganic solid electrolytes from a viewpoint of electrolytes for lithium batteries. Lithium ion conductive inorganic solid electrolytes are largely divided into crystalline and amorphous substances. Crystalline substances are known as LiI and Li3N, and also oxygen acid salt. However, when considering application to a battery, its large grain boundary resistance and electrochemical instability would be a problem. Lithium ion conductive amorphous solid electrolytes are divided into an oxide system and a sulfide system. Since most of them do not contain transition metal elements, they are stable against electrochemical reduction, and ions move isotropically in electrolyte. Therefore, ion conduction paths across the grain boundaries may be connected more easily, forming an electrolyte with low grain boundary resistance. As a result of the efforts of the authors in searching new additives substituting LiI, it was found that ...

Energy Technology Data Exchange (ETDEWEB)

Polycarbonate (PC), a non-crystalline resin, and polybutylene terephthalate (PBT), a crystalline resin, can be achieved by means of alloying of improving such various properties as chemical resistance, heat and impact resistance, and formability. This paper describes its manufacturing methods, properties, and market trends. A PC/PBT alloy improves the chemical resistance if the PBT composition ratio is high, but reduces thermal deformation temperature and impact strength. It is regarded adequate, therefore, that the PBT component ratio is set to 20% to 30%. The impact strength is improved by adding elastomer as a third component. The national production amount in 1992 was 4,800 tons a year; price per kilogram is 700 to 800 yen; and the main application is interior and exterior parts for automobiles. While PP and urethane are often used for interior and exterior automotive parts, there is a high possibility of transferring to PC/PBT in the ...

Energy Technology Data Exchange (ETDEWEB)

The diffusion of ion beam injected self-interstitials (I) and their interaction with impurities in crystalline Si has been investigated and modeled. In particular, the I-substitutional carbon (C) interactions have been studied, using a molecular-beam-epitaxy grown Si{sub 1-y}C{sub y} layer interposed between the shallow I-source and a deeper B-spike (marker for I-concentration). Substitutional C atoms are shown to trap I's, to be removed from their substitutional sites, and to form stable precipitates into the C-rich region. The I-trapping mechanism was quantitatively studied by a simulation code. The reactions causing trapping and deactivation are described. In addition, the boron markers approach was extended to the two dimensional (2D) diffusion. High resolution scanning capacitance microscopy was used for quantitative measurements of the 2D boron transient enhanced diffusion induced on a boron delta array by the I's ion beam injected through a ...

International Nuclear Information System (INIS)

The available experimental data on the specific heat, magnetic susceptibility, magnetization, valence, NMR Knight shift and relaxation rate, and the quadrupolar moment of YbPd_2Si_2 are examined within the framework of the single-ion Anderson model. Such an analysis has previously given excellent agreement between theory and experiment for numerous other light heavy-fermion compounds, where crystalline fields do not play a dominant role. For YbPd_2Si_2, substantial crystalline-field splittings make difficult a quantitative comparison with existing exact solutions of the Anderson model. Inconsistencies with the interpretation that a nearly degenerate ground quadruplet determines the low-temperature thermodynamics are pointed out. It is concluded that at least three of the four Kramers doublets participate in the low-T properties. These three doublets should have a splitting of the order of the Kondo temperature, i.e., about 100 K. A simple ...

Energy Technology Data Exchange (ETDEWEB)

We have investigated and modeled the boron diffusion in silicon following ultra-low-energy implantation (500 eV). It is well known that reducing implant energies is an effective way to eliminate transient enhanced diffusion due to the excess of interstitials from the implant. However, for sub-keV B implants diffusion remains enhanced. This enhancement is linked to the presence of a silicon boride layer located at the silicon surface which creates interstitials. This phenomenon is named 'boron enhanced diffusion' (BED). The BED effect is of obvious interest since it counteracts the advantage obtained by reducing the ion implantation energy. For these reasons, we have investigated the diffusion of low-energy boron implanted in crystalline silicon and tested a complete simulation program, which takes into account the effect of boron precipitation and the effect of the silicon boride layer as a source of self-interstitials. Experimental results have ...

Energy Technology Data Exchange (ETDEWEB)

Samples of ultra-high molecular weight polyethylene (UHMWPE) and nylon 66, of grades suitable for use in medical prostheses, were subjected to irradiation using a /sup 60/Co source. The effects of a 10 Mrad dose on percentage crystallinity, tensile behaviour and dynamic mechanical response were established 3 days after irradiation at intervals over a one year period. Crystallinity in UHMWPE was found to increase progressively during this period with consequent changes in mechanical behaviour. It is proposed that the observed ageing process arises from the breakdown of metastable groups in the polymer, which are formed on irradiation, with consequent release of long inter-lamella tie chains. This removes an inhibition to crystal perfection processes, which can occur at room temperature in polyethylene. Infra-red spectroscopic evidence supports the proposal that the metastable species is peroxy or hydroperoxy and that this decomposes on ageing to ...

International Nuclear Information System (INIS)

Ge pre-amorphisation step is used to reduce the high diffusivity and the transient-enhanced diffusion of boron implanted in silicon. The aim of the process is to obtain shallow P"+N junctions. The pre-amorphisation step was performed under different conditions (in ambient temperature and in nitrogen). Following the rapid thermal annealing step, end of range (EOR) defects appear at the amorphous-crystalline interface. These defects could influence the electrical characteristics of the P"+N junctions. An experimental study concerning three samples has been performed without and under a magnetic field of 800 G. The magnetic susceptibility was essentially observed in the case of the reverse current. The impact of the magnetic field, studied by varying the sample temperature, permits us to show an increase of the magnetic susceptibility when the defects present in such structures are electrically active. These results are discussed in comparison with their deep-level ...

Energy Technology Data Exchange (ETDEWEB)

Xe ion irradiation of NiSi, PdSi, and PtSi on Si was performed at various substrate temperatures. The phase formation and mixing behavior of the three monosilicides with their Si substrates are quite different. For NiSi, NiSi/sub 2/ was formed on amorphous Si substrates at 350 /sup 0/C, while NiSi remained stable on crystalline Si substrates even at 400 /sup 0/C. PtSi reacted with Si to form a metastable Pt/sub 4/Si/sub 9/ phase, which decomposed back to PtSi and Si by successive irradiation at higher temperatures. The decomposition of the metastable Pt/sub 4/Si/sub 9/ was easier on crystalline Si substrates than on amorphous substrates. No mixing was observed for PdSi on Si in the temperature range of 35--400 /sup 0/C. The ion mixing results were compared with those from thermal annealing. The importance of demixing of a thermally stable system was explored.

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We have simulated the transient enhanced diffusion (TED) of boron fluoride (BF{sub 2}{sup +}) implanted in crystalline and germanium amorphized silicon. Based on recently published models, the effect of fluorine on boron diffusion in silicon has been introduced and a modelling has been suggested. In order to simulate the boron experimental profiles, we have assumed that fluorine forms clusters involving interstitial boron which reduces the junction depth. Experimental results indicate that fluorine behaviour depends on amorphization energy. Moreover, even no germanium preamorphization is performed, silicon is still amorphized by fluorine species. Hence, BF{sub 2}{sup +} implantation leads to an amorphous/crystalline (a/c) interface near the surface. An improvement of published models is suggested taking into account fluorine effects. The simulations satisfactory reproduce the SIMS experimental profiles for a large scale of experimental ...

Energy Technology Data Exchange (ETDEWEB)

Several models have been proposed for the simulation of boron diffusion during annealing after implantation in silicon. It has been shown that transient enhanced diffusion (TED) tends to disappear at sub-keV implant energies. Under these conditions boron concentration is higher than the boron solubility limit value, precipitation phenomena occur. Extended defects ({l_brace}3 1 1{r_brace}, EOR) formation and boron precipitation affect both the redistribution during the annealing and activation of the boron. For these reasons, we have investigated the diffusion of low energy boron implanted in crystalline silicon and tested a complete simulation program which takes into account the effects of type I defects as a sink for self-interstitials and of boron precipitation. Experimental results have been simulated and consistent parameters have been found to fit the data. Boron enhanced diffusion effect has been studied. Model parameter extractions have been discussed.

International Nuclear Information System (INIS)

Magnetic particles (MAG*SEP"S"M) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP"S"M particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEP"S"M particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEP"S"M particles with a gamma dose equivalent to 100 cycles of use. This irradiation ...

British Library Electronic Table of Contents (United Kingdom)

Crystalline bis(O,O'-di-sec-butyldithiophosphato)platinum(II) was prepared and studied by means of 13C, 31P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. The unit cell of the platinum(II) compound is comprised of one centrosymmetric mononuclear molecule [Pt{S2P(O-sec-C4H9)2}2], in which the dithiophosphate groups display structural equivalence in both 31P NMR and XRD data. A pair of the dithiophosphate ligands exhibit the same S,S'-bidentate chelating structural function and form two planar four-membered chelate rings, [PtS2P], in this molecule. The planar configuration of the [PtS4] chromophore in structure 1 is governed by the dsp2-hybrid state of platinum(II). The structural states of the dithiophosphate groups in two different samples of complex 1 (one crystallised from...

Energy Technology Data Exchange (ETDEWEB)

Major factors that contribute to maximized impact resistance of semicrystalline engineering polymers include increased matrix molecular weight, minimal rubber glass-transition temperature, and optimal rubber-particle size, which depends on matrix type. Additional constraints are posed by the limitations of available materials and commercial requirements. Expanding the understanding of impact-modified crystalline engineering polymers will further extend their property ranges and utility. This chapter describes the phenomenology of certain factors, illustrates a new technique to measure rubber particle size, and contrasts the fracture mechanisms of poly(butylene terephthalate), nylon 66, and polyacetal. 49 refs., 24 figs.

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Reinforced (heterogel) silicate materials containing an amorphous and a crystalline phase are being used more and more industry. Such systems are energetically unsaturated and therefore promising for use in catalysts. The authors used two reinforced materials as supports: an aluminosilicate containing a zeolite (the cracking catalyst, tseokar) and asbestos-containing aluminosilicate. The active component was introduced by impregnation, and this was followed by heat treatment during which the chemical composition and porous structure were formed. The impregnating mixture consisted of solutions of potassium sulfate and vanadate of the required concentrations. The testing shows that reinforced heterogel systems are promising as support materials for sulfuric acid catalysts.

Energy Technology Data Exchange (ETDEWEB)

A method using a focused ion beam (FIB) to prepare a silicon amorphous material is presented. The method involves the redeposition of sputtered material generated during the interaction of the Ga{sup +} ion beam with a silicon substrate material. The shape and dimensions of this amorphous material are self-organized and reproducible. The stability of this amorphous material under electron irradiation was investigated in the transmission electron microscopy (TEM). Electron irradiation can induce recrystallization of the amorphous material, resulting in the lateral and vertical growth, starting at an amorphous-crystalline interface, of polysilicon containing defects.

International Nuclear Information System (INIS)

By treatment with beta or gamma rays, PTFE waste is converted to high-grade PTFE fine powder. High-molecular weight PTFE is degraded to low-molecular weight PTFE. Due to this the density, the degree of crystallinity, and the melt flow index are increased, which enhances the brittleness of the material. Irradiation of PTFE thus facilitates milling and makes the material pourable and free-flowing. Milled PTFE fine powder, lie PTFE plastic, combines temperature resistance, weather fastness, and chemical stability with good slip behaviour and antiadhesive properties. Areas of application for fine powder include additives for plastics, printing inks, nonstick coatings, and antifriction lacquers. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Apparent growth of amorphous layers during low temperature annealing was observed in low energy Ge{sup +}-implanted (0 0 1)Si by high-resolution transmission electron microscopy. The occurrence of abnormal growth is due to the randomization of heavily damaged regions beneath the original amorphous/crystalline interfaces. The randomization process is attributed to the strain, incurred by the presence of a high density of large Ge atoms in the heavily damaged Si substrate, relaxation to lower the free energy of the systems. The randomization upon annealing may be fruitfully applied to minimize the transient enhanced diffusion in shallow junction formation.

International Nuclear Information System (INIS)

Polytetrafluoroethylene was obtained by radiation induced polymerization of tetrafluoroethylene in acetone at 195 K. An average diameter of the products was very small compared with commercial one; it was about 0.3 micro-meters. The yield was reached to 100% with a dose of 4 kGy. The crystallinity of the products is decreasing with increasing dose. The products become amorphous, for higher irradiation doses. It was found that PTFE obtained by irradiation of TFE in acetone at 195 K has branching structure. This was demonstrated by means of "1"9F MAS NMR. (Author)

International Nuclear Information System (INIS)

This paper describes Z-contrast scanning transmission electron microscopy used to study the connection between dopant precipitation and phase transformation in high dose In"+ and Sb"+ implanted Si. In the case of In, the observations confirm a heterogeneous nucleation model. Images of the precursor precipitates give the first measurement of the diffusion coefficient in amorphous Si, with an enhancement of 10"7 over tracer crystalline values. With Sb"+ implants enhanced homogeneous nucleation is observed. The connection between these results and the transient enhanced diffusion observed in crystallized Si is discussed.

Energy Technology Data Exchange (ETDEWEB)

The effect of high-energy-density laser surface melting on the morphology and properties of a cast Ni-based superalloy containing 33 wt percent Mo and 17 wt percent W is investigated experimentally. Significant improvements in the hardness and the wear resistance in both dry and acid environments are atttributed to the elimination of segregation in the laser-treated zone, where solid solubility increases, crystalline structure becomes finer, and the fine dendritic, cellular dendritic, cellular, and plane-front solidification structures are evenly distributed.

Energy Technology Data Exchange (ETDEWEB)

Oxyanions of uranium, selenium, chromium, arsenic, technetium, and chlorine (as perchlorate) are frequently found as contaminants on many DOE sites, and in other areas of the U.S.. A potential remediation method is to react the contaminated water with zero-valent iron (ZVI). We are performing fundamental investigations of the interactions of the relevant compounds with Fe filings and single- and poly-crystalline surfaces. The aim of this work is to develop the physical and chemical understanding that is necessary for the development of cleanup techniques and procedures.

Energy Technology Data Exchange (ETDEWEB)

The electronic structure of the clusters (V/sub 3/Si/sub 4/)/sup 12 -/, (Nb/sub 3/Sn/sub 4/)/sup 12 -/(Mo/sub 3/Ge/sub 4/)/sup 15 -/ in crystalline V/sub 3/Si, Nb/sub 3/Sn, Mo/sub 3/Ge compounds is calculated by the Extended Hueckel method. The influence of different types of radiation induced defects on the density of states at the Fermi level (the anti-site defects, the displacement of atoms in linear chains, the vacancy-interstitial type defects) is considered.

Energy Technology Data Exchange (ETDEWEB)

A study was made on complex formation of thiosemicarbazide diacetic acid (H/sub 2/L) with neodymium (3), holmium (3) and erbium (3) in solutions and formation of complexes of metal: ligand=4:1 composition was revealed. Synthesis conditions were developed and products of LnLClxnH/sub 2/O, LnLOHxnH/sub 2/O, Na(LnL/sub 2/)xnH/sub 2/O composition were separated in crystalline state. It was shown, that H/sub 2/L behaves in these compounds as tripod ligand with O, O, N, N donor atoms.

Science.gov (United States)

A process is provided for conducting organic compound conversion over a catalyst composition comprising a specially treated crystalline zeolite having a high initial silica-to-alumina mole ratio, said zeolite having been synthesized from a reaction mixture comprising a diamine as a cation source. The treatment of the zeolite material comprises the sequential steps of reacting the zeolite with a dilute hydrogen fluoride solution, contacting the hydrogen fluoride solution reacted material with aluminum chloride vapor, and then treating the aluminum chloride contacted material to convert it to hydrogen form.

International Nuclear Information System (INIS)

Crystalline Pd_9Si_2 possesses an orthorhombic structure (Pnma) that is characterized by augmented triangular prismatic coordination of the silicon atoms such as that which occurs in several metal-rich transition-metal silicides. Recent neutron diffraction results for deuterium solution in this crystalline phase have indicated that deuterium occupies only one type of interstice, i.e., a Pd-defined pyramidal site in a four-fold position situated on a quadrilateral face of an empty triangular prism. The vibrational dynamics of both H and D located at this site were investigated by neutron vibrational spectroscopy. The low-temperature density of states (DOS) of H in Pd_9Si_2H_0_._2_5 indicates three well-defined optic vibrations located at 49.4, 67.2 and 75.5 meV. The lowest-energy feature is assigned to the normal-mode vibration perpendicular to the pyramidal base and the two higher-energy features are assigned to the two orthogonal normal-mode ...

International Nuclear Information System (INIS)

Microstructure and electrical properties of iron oxide Fe_2O_3 thin films prepared by spray pyrolysis method have been experimentally characterized. The effect of substrate temperature as well as deposition time on the structural features (crystallite size and microstrain) and electric resistivity of these films has been investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) characterized the structure study. The results of X-ray diffraction showed that with increasing substrate temperature bias the film structure changed from amorphous to crystalline at the same deposition time. At a substrate temperature of 350 deg. C and low deposition time, #alpha#-Fe_2O_3 appears almost in amorphous form. With rising the substrate temperature and deposition time, the crystallinity was improved. At T_s_u_b>350 deg. C, a well-crystallized rhombohedral phase of #alpha#-Fe_2O_3 was obtained. Single order Voigt profile method has been ...

Energy Technology Data Exchange (ETDEWEB)

The paper reported the results of fiscal 1994 studies on solar energy in the New Sunshine Project. Relating to the technical development for the practical use of photovoltaic power systems, the development of manufacturing technologies for low-cost substrates and the development of element technology for manufacturing low-cost polycrystalline cells/modules were reported as the development of technology for thin substrate polycrystalline solar cells for practical use. As to the research on fabrication technology for thin film solar cells for practical use, reports were made on the research on low-cost fabrication technology for large-area modules and the technological development for qualitative improvement, etc. In respect to the technological development for super-high efficiency solar cells, reported were the technological development for super-high efficiency single crystalline silicon solar cells and the technological development for ...

International Nuclear Information System (INIS)

Ultraviolet light can be used to immobilize biomolecules onto thiol reactive surfaces in order to, e.g., make biosensors. The mechanism involves light-induced formation of free, reactive thiol groups in disulphide containing molecules. This technology allows for the creation of arrays of biomolecules with a high degree of reproducibility, circumventing the need for often expensive nano/micro-dispensing technologies. The ultimate size of the immobilized spots is defined by the focal area of the UV beam. Light-induced immobilization has the added benefit that the immobilized molecules will be spatially oriented and covalently bound to the surface. In this paper, we demonstrate the utility of a sensor array created with the new sensor technology when integrated into a microfluidic system. Protein arrays made using light-induced immobilization showed successful antigen/antibody binding in a flow cell allowing the visualisation of real time binding and enzyme activity. ...

International Nuclear Information System (INIS)

The influence of chemical composition and heat treatment on a low-carbon steel, chromium steel and high speed steel has been examined by polarisation curves and electrochemical parameters deduced from the Tafel plots. The electrochemical corrosion resistance, which is small between the as-received steels become greater after heat treatment, following the order: carbon steel < chromium steel #approx# high speed steel. To explain these differences, the nano- and microstructure of the steels has been characterized by the ex situ techniques of atomic force microscopy and optical microscopy, before and after surface etching with Nital (a solution of 5% HNO_3 in ethanol). This causes preferential attack of the ferrite phases showing the carbide phases more clearly. From these nanostructural studies it was possible to better understand why the passive films formed on chromium steel and high speed steel have superior protective properties to those formed on carbon ...

International Nuclear Information System (INIS)

This introductory text treats thermodynamics as an incomplete description of quantum systems with many degrees of freedom. Its main goal is to show that the approach to equilibrium -with equilibrium characterized by maximum ignorance about the open system of interest- neither requires that many particles nor is the precise way of partitioning, relevant for the salient features of equilibrium and equilibration. Furthermore, the text depicts that it is indeed quantum effects that are at work in bringing about thermodynamic behavior of modest-sized open systems, thus making Von Neumann's concept of entropy appear much more widely useful than sometimes feared, far beyond truly macroscopic systems in equilibrium. This significantly revised and expanded second edition pays more attention to the growing number of applications, especially non-equilibrium phenomena and thermodynamic processes of the nano-domain. In addition, to improve readability and reduce unneeded ...

International Nuclear Information System (INIS)

The synthesis of narrowly dispersed nanocrystalline TiO_2 was investigated with a surfactant aided solvothermal synthetic method in toluene solutions. When a sufficient amount of titanium isopropoxide, Ti[OCH(CH_3)_2]_4 (TIP), was added to the solution, the shapes of TiO_2 nanoparticles changed from spheres to rods. The aggregated microstructures of the nano-sized TiO_2 in systems of spheres, rods, and mixtures of spheres and rods was studied using TEM. The morphological shape of the aggregation was described in terms of the fractal dimensions. We used a box-counting method to get the fractal dimension of these systems. The fitted fractal dimensions for spheres, sphere/rod mixtures, and rods are D = 1.54, D = 1.81, and D = 1.89, respectively. The fractal dimension changed from 1.54 to 1.9 with the TIP/toluene ratio, indicating that the growth mechanism for aggregations showed different behaviors.

International Nuclear Information System (INIS)

This paper presents the first results on formation and study of structure and properties of micro- and nanocomposite combined coatings. By means of modeling the deposition processes (deposition conditions, current density-discharge, plasma composition and density, voltage) we formed the three-layer nanocomposite coatings of Ti-Al-N/Ti-N/Al_2O_3. The coating composition, structure and properties were studied using physical and nuclear-physical methods. The Rutherford proton and helium ion backscattering, scanning electron microscopy with microanalysis, grazing incidence X-ray diffraction, as well as nanohardness tests (hardness) were used. Measurements of wear resistance and corrosion resistance in NaCl, HCl and H_2SO_4 solutions were also performed. For testing mechanical properties such characteristics of layered structures as hardness H, elastic modulus E: H"3/E"2 etc. were measured. It is demonstrated that the formed three-layer nanocomposite coatings have hardness of 32 to 36 GPa ...

British Library Electronic Table of Contents (United Kingdom)

Ferroelectric barium strontium titanate (Ba0.7Sr0.3TiO3)(BST) thin films have been prepared from barium 2-ethylhexanoate [Ba[CH3(CH2)3CH(C2H5)CO2]2], strontium 2-ethylhexanoate [Sr[CH3(CH2)3CH(C2H5)CO2]2] and titanium(IV) isopropoxide [TiOCH(CH3)2]4 precursors using a modified sol-gel technique. The precursor except [TiOCH(CH3)2]4 were synthesized in the laboratory. Transparent and crack-free films were fabricated on pre-cleaned quartz substrates by spin coating. The structural and optical properties of films annealed at different temperatures have been investigated. The as-fired films were found to be amorphous that crystallized to the tetragonal phase after annealing at 550degreeC for 1h in air. The lattice constants "a" and "c" were found to be 3.974A and 3.990A, respectively. The grain...

Science.gov (United States)

Electrospinning has gained much attention in the past decade as an effective means of generating nano- to micro-scale polymer fibers that resemble native extracellular matrix. High porosity, pore interconnectivity, and large surface area to volume ratio of electrospun scaffolds make them highly conducive to cellular adhesion and growth. However, inherently small pores of electrospun scaffolds do not promote adequate cellular infiltration and tissue ingrowth. Cellular infiltration into the scaffold is essential for a range of tissue engineering applications and is particularly important in skin and musculoskeletal engineering. Pore size, porosity, and pore interconnectivity dictate the extent of cellular infiltration and tissue ingrowth into the scaffold; influence a range of cellular processes; and are crucial for diffusion of nutrients, metabolites, and waste products. A number of electrospinning techniques and postelectrospinning modifications have, therefore, ...

British Library Electronic Table of Contents (United Kingdom)

We describe a method for the analysis of multi-site phosphorylation in serine/threonine (Ser/Thr)-rich protein sequences. Site-specific mutagenesis was used to introduce tryptic cleavage sites in the serine glutamine/threonine glutamine cluster domain (SCD) of the human checkpoint protein kinase (Chk2). The mutant proteins were shown to autophosphorylate on residues that are inducibly phosphorylated when mammalian cells are exposed to ionizing radiation (serine 33/35, serine 516, threonine 68 and threonine 432). Five Ser/Thr clusters within the SCD were flanked by arginine or lysine residues to produce tryptic peptides for nanospray liquid chromatography (nanoLC)/linear quadrupole ion trap Fourier transform ion cyclotron resonance mass spectrometry. Phosphorylation sites were assigned usin...

International Nuclear Information System (INIS)

The lasing of the first free-electron laser (FEL) in the world was successfully carried out in 1977, so the history of FELs as a light source is not so long. But FELs are now utilized for research in many scientific and engineering fields owing to such characteristics as tunability of the wavelength, and short pulse and high peak power, which is difficult utilizing a common light source. Research for industrial applications has also been carried out in some fields, such as life sciences, semiconductors, nano-scale measurement, and others. The task for the industrial use of FEL is the realization of high energy efficiency and high optical power. As a means of promoting realization, the combining of an FEL and superconducting linac is now under development in order to overcome the thermal limitations of normal-conducting linacs. Further, since tuning the wavelength is carried out by changing the magnetic density of the undulator, which is now induced by moving part ...

International Nuclear Information System (INIS)

We present an approach for fabrication of intentionally positioned epitaxial InAs QDs in a micron sized light emitting diode. For site-selective growth, a combination of molecular beam epitaxy (MBE) and focused ion beam (FIB) implantation technology in an all-ultra-high-vacuum (UHV) setup has been employed. Single dot occupancy of almost 55 % on FIB patterned nano-depressions was successfully achieved. Thereafter, carrier injection and subsequent radiative recombination from the positioned InAs/GaAs self-assembled QDs was investigated by embedding these QDs in the intrinsic part of a GaAs-based micron sized p-i-n junction device. Few or single dot are expected to be electrically addressed in these devices. We report results from electroluminescence (EL) measurement which proves the single dot characteristics of our device. The EL spectra consist of sharp emission lines and their dependence on injection current shows linear behavior for exciton and quadratic ...

International Nuclear Information System (INIS)

This work has been undertaken with a view to study the effect of lanthanum content on properties of PLZT ceramics. The polycrystalline complex compounds of PLZT with Pb_1_-_xLa_x(Zr_0_._4_0Ti_0_._6_0)_1_-_x_/_4O_3, +10% PbO formula were prepared from the nano-size individual oxides powders by hot-pressed process. Transparent PLZT (x/40/60) bulk ceramics with pure tetragonal phase was obtained. The studies of the microstructures, dielectric and ferroelectric properties of the ceramics were carried out. The experiment results showed that when La content increased from 7 to 13 mol.%, the grain size increased from 2 to 7 #mu#m. La content also effects the dielectric property obviously, the dielectric constant increased with La content increasing. Moreover, the ferroelectric properties are sensitive to the variation of La content.

Energy Technology Data Exchange (ETDEWEB)

Kitchen oils (olive, soybean and butter) are selected for carbon coatings on LiFePO{sub 4}. The surface properties of LiFePO{sub 4} are unknown or vary depending on synthetic methods. The multi-functional groups of fatty acids in the oils can orient properly to cope with the variable surface properties of LiFePO{sub 4}, which can lead to dense carbon coatings. The low price and low toxicity of kitchen oils are other advantages of the coating process. LiFePO{sub 4} (D{sub 50} = 121 nm)combined with the carbon coating enhances the rate capability. Capacities at the 2C rate reach 150 mAh g{sup -1} or higher. The charge retention values of 2.0C/0.2C are between 94.4 and 98.9%. (author)

Energy Technology Data Exchange (ETDEWEB)

We review recent development in separations and mass spectrometric instrumentation for sensitive and high-throughput proteomic analyses. These efforts have been primarily focused on the development of high-efficiency (separation peak capacity of ~103) nanoscale liquid chromatography (nanoLC; e.g., flow rates extending down to ~20 nL/min at optimal separation linear velocities through narrow packed capillaries) in combination with advanced mass spectrometry (MS), including high sensitivity and high resolution Fourier transform ion cyclotron resonance (FTICR) MS. This technology enables MS analysis of low nanogram-level proteomic samples (i.e., nanoscale proteomics) with individual protein identification sensitivity at the low zeptomole-level. The resultant protein measurement dynamic range can reach 106 for nanogram-sized proteomic samples, while more abundant proteins can be detected from complex sub-picogram size proteome samples. The average proteome ...

International Nuclear Information System (INIS)

An attempt has been made to grow L-tartaric acid nicotinamide (LTN); a complex of tartaric acid, by employing a modified unidirectional method. The crystalline structure and quality are investigated by single crystal XRD and rocking curve studies. The linear and nonlinear optical properties are studied by UV-vis-NIR spectral analysis, SHG test, phase matching and laser induced damage threshold measurement. For comparison, parallel growth of the crystal was carried out by conventional method and the properties of the LTN samples grown by the conventional and unidirectional methods are investigated. The mechanical, photoconductivity and dielectric behavior of LTN crystals are also investigated.

International Nuclear Information System (INIS)

We have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss conflicting observations on As"+ implanted Si.

Energy Technology Data Exchange (ETDEWEB)

We have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss conflicting observations on As/sup +/ implanted Si.

British Library Electronic Table of Contents (United Kingdom)

Nylon copolymer (PA6, 66) and ethylene propylene diene (EPDM) blends with and without compatibilizer were prepared by melt mixing using Brabender Plasticorder. The thermal stability of nylon copolymer (PA6, 66)/ethylene propylene diene rubber (EPDM) blends was studied using thermogravimetric analysis (TGA). The morphology of the blends was investigated using scanning electron microscopy (SEM). In this work, the effects of blend ratio and compatibilisation on thermal stability and crystallinity were investigated. The incorporation of EPDM rubber was found to improve the thermal stability of nylon copolymer. The kinetic parameters of the degradation process were also studied. A good correlation was observed between the thermal properties and phase morphology of the blends. By applying Coats ...

International Nuclear Information System (INIS)

Hydrostatic weighing was used to measure the pre-melt density of crystalline eutectic mixtures of alkaline metal chlorides of the compositions (mole fractions): 0.605 LiCl + 0.395 CsCl, 0.585 LiCl + 0.415 KCl, 0.297 NaCl + 0.246 KCl + 0.457 CsCl, and 0.348 NaCl + 0.652 CsCl with melting points 598, 628, 753, 763 K, respectively, as a function of temperature. In the same temperature ranges, the compressibility and molar volume of eutectics as well as their sudden change upon melting were estimated. Unusual variations of these properties were revealed near the crystal/liquid phase transition, which were related to local disordering of particle configuration

Energy Technology Data Exchange (ETDEWEB)

In-situ TEM investigations during thermal treatment of amorphous Pd{sub 81}Si{sub 19} have been performed. It was found that crystalline nuclei are formed near the perforation edge of the hole produced by electrochemical polishing. After impinging with neighboring crystals, a crystallization front formed which was aligned parallel to the perforation edge. The crystallization front moved in the direction perpendicular to the perforation edge. Crystal growth was found to proceed faster in thinner parts of the specimen than in thicker parts. The results are described qualitatively within a thermodynamic model taking into account volume-, surface- and interfacial free energies and an appropriate specimen geometry.