Energy Technology Data Exchange (ETDEWEB)

The authors report the fabrication and characterization of a low temperature (200--400 C) thin film gas sensor constructed from a MOCVD-grown yttria-stabilized zirconia (YSZ) layer sandwiched between two platinum thin film electrodes. A reproducible gas-sensing response is produced by applying a cyclic voltage which generates voltammograms with gas-specific current peaks and shapes. Growth conditions are optimized for preparing YSZ films having dense microstructures, low leakage currents, and maximum ion conductivities. In particular, the effect of growth temperature on film morphology and texture is discussed and related to the electrical and gas-sensing properties of the thin film sensor device.

International Nuclear Information System (INIS)

Yttria stabilized zirconia (YSZ) with 8 mol% Y was deposited by reactive magnetron sputtering onto oxidized (100) silicon substrates. It was possible to switch film texture from (111) to (200) by applying a strong RF substrate bias. Transmission electron microscopy showed that the film deposited under bias is porous and exhibits nanoscaled grains, whereas the film deposited without bias is dense and columnar. The ionic conductivity as a function of temperature revealed an activation energy of 1.04 eV. The mechanical stress could be tuned to low values by thermal post-annealing. Using the dense (111) film as electrolyte layer, and the porous (200) film as an interlayer to a porous Pt anode, an open circuit voltage of 0.85 V was obtained in a micro machined fuel cell structure.

British Library Electronic Table of Contents (United Kingdom)

In this paper, we study the optical properties of indium sulfide thin films to establish the best conditions to obtain a good solar cell buffer layer. The In2S3 buffer layers have been prepared by chemical bath deposition (CBD) and thermal evaporation (PVD). Optical behavior differences have been found between CBD and PVD In2S3 thin films that have been explained as due to structural, morphological and compositional differences observed in the films prepared by both methods. The resultant refractive index difference has to be attributed to the lower density of the CBD films, which can be related to the presence of oxygen. Its higher refractive index makes PVD film better suited to reduce overall reflectance in a typical CIGS solar cell.

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YBCO films were fabricated on PLD-CeO{sub 2}/IBAD-Gd{sub 2}Zr{sub 2}O{sub 7}/Hastelloy substrates using the advanced TFA-MOD process. The effective thickness of the CeO{sub 2} buffer layer for obtaining high I{sub c} was investigated in short samples of YBCO films. The CeO{sub 2} buffer layer was epitaxially grown on an IBAD-Gd{sub 2}Zr{sub 2}O{sub 7} template tape with 18 deg. of {delta}{phi} by a reel-to-reel PLD system. The in-plane grain alignment of PLD-CeO{sub 2} buffer layers rapidly improved with the thickness and saturated at a critical thickness of 0.8 {mu}m. The size of CeO{sub 2} grains was about 1 {mu}m at the saturated thickness of {delta}{phi}. YBCO films with the thickness of 1 {mu}m were deposited by the TFA-MOD on the CeO{sub 2} buffer layer with different thickness films. Improvement of the CeO{sub 2} ...

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Cu/YSZ cermet (40 and 60 vol.% Cu powder with balance YSZ) is a more economical cathode material than the conventional Ni/YSZ cermet for high temperature electrolysis (HTE) of water vapor and it was successfully fabricated by high-energy ball-milling of Cu and YSZ powders, pressing into pellets (o 13 mm x 2 mm) and subsequent sintering process at 700 deg. C under flowing 5%-H{sub 2}/Ar gas. The Cu/YSZ composite material thus fabricated was characterized using various analytical tools such as XRD, SEM, and laser diffraction and scattering method. Electrical conductivity of sintered Cu/YSZ cermet pellets thus fabricated was measured by using 4-probe technique for comparison with that of conventional Ni/YSZ cermets. The effect of composite composition on the electrical conductivity was investigated and a marked increase in electrical ...

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Successful interface engineering requires compositional and electronic material characterization as a prerequisite for understanding and intentionally generating interfaces in photovoltaic devices. The paper gives an overview with several examples, all referring to Cu(In,Ga)(S,Se){sub 2} ('CIGSSe')-based solar cells, with an emphasis on characterization using highly specialized methods, such as elastic recoil detection analysis, X-ray emission spectroscopy and photoelectron spectroscopy using synchrotron and ultraviolet light for excitation, inverse photoemission spectroscopy and Kelvin probe force microscopy. First, the determination of the depth profile of the band gap energy E{sub g} in the absorber layer is demonstrated. The modification of E{sub g} towards both interfaces is discussed in terms of beneficial electronic effects. Next, the interface between absorber and buffer layers with alternative and ...

International Nuclear Information System (INIS)

Semiconductor properties of passive films formed on the Fe-18Cr alloy in a borate buffer solution (pH = 8.4) and 0.1 M H_2SO_4 solution were examined using a photoelectrochemical spectroscopy and an electrochemical impedance spectroscopy. Photo current reveals two photo action spectra that derived from outer hydroxide and inner oxide layers. A typical n-type semiconductor behaviour is observed by both photo current and impedance for the passive films formed in the borate buffer solution. On the other hand, a negative photo current generated, the absolute value of which decreased as applied potential increased in the sulfuric acid solution. This indicates that the passive film behaves as a p-type semiconductor. However, Mott-Schottky plot revealed the typical n-type semiconductor property. It is concluded that the passive film on the Fe-18Cr alloy formed in the borate buffer solution is composed of both ...

International Nuclear Information System (INIS)

Rapid self-aggregation of Ni nanodots on Si substrate covered with a thin SiO_2 buffered layer is investigated. The Ni nanodots can hardly self-aggregate on highly heat-dissipated Si substrate with a thermal conductivity of 148 W/m K. Adding a 200-A-thick SiO_2 buffer with an ultralow thermal conductivity of 1.35 W/m K prevents the formation of NiSi_2 compounds, enhances the heat accumulation, and releases the adhesion at Ni/Si interface, which greatly accelerates the self-assembly of Ni nanodots. Dense Ni nanodots with size and density of 30 nm and 7x10"1"0 cm"-"2, respectively, can be formatted after rapid thermal annealing at 850 deg. C for 22 s.

British Library Electronic Table of Contents (United Kingdom)

In the present contribution, the innovative in situ Raman micro-spectroscopy was applied to investigate the in vitro reactivity of various bioactive glasses. All the investigated glasses belonged to the Na2O\\K2O-CaO-P2O5-SiO2 system, but contained sensibly different percentages of network modifiers. The glasses were immersed for increasing times, up to 96h, in simulated body fluid (SBF) and in tris-buffered (TRIS) solution. In this way, two fundamental items were addressed, i.e. the effect of the glass composition and the nature of the soaking fluid on the overall reactivity. As regards the SBF, all the glasses were able to promote the formation of a hydroxyl-carbonate apatite (HCA) surface layer in very short times. The reaction rate was particularly quick for the 45S5 Bioglass and for it...

International Nuclear Information System (INIS)

The lateral bearing device is made of 7 lateral supports, each positioned to allow the displacement of the steam generator due to thermal or seismic effects. Each support includes a buffer plate that can be positioned on the steam generator using a position control assembly. This control assembly consists of a screw jack arrangement where the nut is fastened via an energy absorbing layer to a footplate that is fixed to the concrete wall of the steam generator enclosure. 4 figs.

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We have investigated the generation and propagation of misfit dislocations in strained In/sub y/Ga/sub 1-//sub y/As/GaAs multiquantum wells grown by molecular-beam epitaxy, with cross-sectional transmission electron microscopy. The samples are of excellent optical quality, with multiquantum wells having well widths of 100 A, being characterized by excitonic linewidths and Stokes shifts of 1.5--2.5 and 1--2 meV, respectively. We have examined the growth of 2-..mu..m-thick multiquantum-well samples grown either directly on GaAs, or with an intermediate composition buffer layer, and for the cases of small (y = 0.07) and large (y = 0.16) misfits. It is seen that for the case of quantum wells with small misfit, grown directly on GaAs, metastable growth can be achieved. This is confirmed by low-temperature absorption measurements and from transmission electron microscopy experiments performed both before and after post-growth thermal annealing. In ...

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Electronic properties of passive films formed on Fe at various applied potentials in pH 8.5 buffer solution were examined through the photocurrent measurement and impedance spectroscopy. Passive film formed on Fe at relatively low potentials was found to be r-FeOOH layer and internal r-Fe{sub 2}O{sub 3} layer. However, the r-FeOOH layer became unstable and disappeared at potentials below 400mV and hence may be an adsorbed layer. An electronic band structure model for the passive film of Fe was suggested on the basis of the spinel band model with involving two types of electronic excitation processes, i. e., the p-d and the d-d transition together. The effects of applied potential on the photocurrent behaviors of the passive film on Fe were explained appropriately by separating the photocurrent spectra depending on the transition type. The Mott-Schottky behavior for the passive film ...

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The project has been developing Yttria Stabilized Zirconia (YSZ)-Alumina Composites as an electrolyte of a self-support type planar Solid Oxide Fuel Cell (SOFC) from the following points of view: a path of alumina particles with high thermal conductivity can be designed as an electrolyte sheet; there are some possibilities that the electrolyte can be enhanced in mechanical strength. As previously reported, these composite materials have higher mechanical strength and better thermal shock resistance than those of YSZ. These composites containing 0-30 wt% of Al[sub 2]O[sub 3] were measured by AC impedance method at temperatures of 250-1,000[degree]C. Electrical conductivities of 8YSZ without Al[sub 2]O[sub 3] and a composite consisting of 80 wt% YSZ and 20 wt%Al[sub 2]O[sub 3] as sintered samples were 1.2 x 10[sup -1]S/cm and 1.0 x 10[sup -1]S/cm respectively at 1,000[degree]C. The composite containing 20 ...

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Creation of new multi-composite materials is an essential issue to attain an innovative improvement of the current nuclear technology. In this paper, some highlights are focused on the research of creation of those materials and the relating subjects in NIRIM. (1) The KOH corrosion test method are expected to be efficiently available in the limited cases instead of Na corrosion test one. (2) The preliminary creation of the multi-composite ceramics were achieved by Y- ion implantation into sapphire and the RF sputtering, of which the specified orientation was realized by the existence of the buffer layer. The importance of the defect control are described with the relation to the corrosion resistance improvement. (3) The ion beam induced phenomena have been investigated on the surface change of silica glass and the crystallization of Cu film on SrTiO{sub 3}. (4) The electronic states of the alkali-metal adsorbed surfaces and that of the ...

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FeSi{sub 6}/graphite composite was prepared by mechanical ball milling. The FeSi{sub 6} alloy particles consist of an electrochemically active silicon phase and inactive phases FeSi{sub 2}, distributed uniformly in the graphite matrix. The composite anode offers a large reversible capacity (about 800 mAh g{sup -1}) and good cycleability, due to the buffering effect of the inactive FeSi{sub 2} phase and graphite layers on the volumetric changes of Si phase during lithium-Si alloying reaction. Since FeSi{sub 6} alloy is a low-cost industrial material, this alloy compound provides a possible alternative for development of high capacity lithium-ion batteries. (author)

International Nuclear Information System (INIS)

The chemical composition and the semiconducting properties of passive films formed on nickel based alloy (Alloy 600) in acidic sulphate solution, pH 2.0 at room temperature were studied using Auger analysis, voltammetric techniques and the Mott-Schottky approach. The results obtained revealed that the presence of both chromium and mixed nickel-iron oxides in the films leads to the development of a p-n heterojunction, which controls their electronic structure, similarly manner to the case of stainless steels and Alloy 600 in borate buffer solution. This behavior has been interpreted as representing of an oxide system, which has a duplex character, with an inner p-type semiconducting region, mainly formed by chromium oxide and an outer n-type semiconducting region, containing iron oxide. It could also be observed that the nickel oxide present in the films acts as a barrier layer conferring improved protection.

Science.gov (United States)

... a buffer of all biological resources in the Kenai Fjords National Park Area. Data from Alaska Fish ... ...

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In order to apply chemical-looping combustion to a practical power plant, carbon deposition on the solid particle is one of the key problems to be overcome. Six kinds of solid particles were examined to clarify the kinetic behavior of carbon deposition. The effects of the solid composition, feed gas composition, and reaction temperature on carbon deposition were investigated by thermogravimetrical reactor on the basis of NiO/YSZ particle. From the viewpoints of both reactivity and resistance against carbon deposition, the particle of NiO mixed with YSZ (i.e., yttria-stabilized zirconia) was found to be a good candidate for chemical-looping combustion. It has been observed that carbon deposition could be completely avoided with very low concentration of water vapor. By means of a proposed model, the condition that carbon deposition would be avoided was identified. 12 refs., 8 figs., 2 tabs.

International Nuclear Information System (INIS)

Self-assembled quantum dots (QDs) are envisioned as building blocks for realization of novel nanoelectronic devices, for which the site-selective growth is highly desirable. This thesis presents a successful route toward selective positioning of self-assembled InAs QDs on patterned GaAs surface by combination of in situ focused ion beam (FIB) implantation and molecular beam epitaxy (MBE) technology. First, a buffer layer of GaAs was grown by MBE before a square array of holes with a pitch of 1-2 #mu#m was fabricated by FIB implantation of Ga and In, ions respectively. Later, an in-situ annealing step followed by InAs deposition was performed. The InAs QDs were preferentially formed in the holes generated by FIB. The influence of ion dose, annealing parameters and InAs amount was investigated in this work. With optimized parameters, more than 50 % single dot occupancy per hole is achieved. Furthermore, the photoluminescence spectra from ...

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The temperature dependence of the spontaneous magnetization of epitaxial iron films with a thickness ranging from d=20 to 200nm has been measured. The films are grown on GaAs (100) substrates which are covered by a 150nm thick silver (100) buffer layer. For three-dimensional BCC iron it was observed already in 1929 that saturation of the spontaneous magnetization for T->0 is perfectly described by a T{sup 2} power law. On the other hand, for thin two-dimensional (2D) iron films a T{sup 3/2} law has been established in many recent experimental investigations. In our iron films grown on diamagnetic silver, this dimensionality change occurs at a thickness between d=100 and 200nm. Comparison of the here-observed T{sup 3/2} coefficients with those on iron films grown on paramagnetic tungsten (110) shows that the 2D interactions are {approx}20 times larger in the films on tungsten. Recent results on Fe films which are grown directly on GaAs ...

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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 ...

Science.gov (United States)

Room-temperature continuous-wave (cw) operation is achieved in the MBE (molecular-beam epitaxy)-grown InGaP/InGaAlP double-heterostructure (DH) visible laser diodes with a threshold current of 110 mA. The lasing wavelength and threshold current density under pulsed operation are 666 nm and as low as 3.9 kA/cm/sup 2/, respectively. This result is achieved by the introduction of H/sub 2/ into the growth chamber during growth, the continuous growth from one layer to the next layer, and the introduction of a GaAs buffer layer. InGaP/InGaAlP quantum well structures are also grown. From photoluminescence measurements, the conduction-band discontinuity ..delta..E/sub c/ is estimated to be 0.43 of the band-gap difference ..delta..E/sub g/. Furthermore, the multiquantum-well (MQW) structure is found to be stable under thermal treatment at temperatures as high as 750 /sup 0/C. Room-temperature pulsed operation of ...

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In situ scanning tunneling microscopy has been used to study the nucleation and growth mechanisms and the structure of passive films formed on Cu(111) surfaces in 0.1 M borate buffer solution (pH 9.3). A surface topography characterized by terraces with monoatomic steps is obtained after potentiodynamic reduction down to {minus}1.12 V/standard hydrogen electrode (SHE), of the electropolished surface exposed to air. The formation of a single Cu{sub 2}O passive layer at 0.03 V/SHE proceeds first by a roughening of the steps assigned to a locally blocked step flow process due to a competition between dissolution and preferential nucleation of the oxide at the steps. The observed oxide nuclei are 2--3 nm wide and about one atomic plane high. This process leads to the complete coverage of the terraces by a grain-like structure of the oxide film. The initial terrace topography is completely altered. Thickening of this oxide layer ...

International Nuclear Information System (INIS)

As an engineered barrier system in the geological disposal of high-level waste, multibarrier system is considered. Multibarrier system consists of the vitrified waste, the overpack and the buffer. Bentonite is one of the potential material as the buffer because of its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. As the construction technology of the buffer, the block installation method and in-situ compaction method, etc, are being investigated. The block installation method is to emplace the buffer blocks manufactured in advance at the ground facility, and construction processes of the block installation method at the underground will be simplified compared with the in-situ compaction ...

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The poisoning effects of various trace contaminants in the coal-derived syngas stream at ppm and sub-ppm level on the performance of Ni-YSZ/YSZ/LSM solid oxide fuel cells were studied at extended duration. The thermochemical nature of impurities such as PH{sub 3}(g) and CH{sub 3}Cl(g) in presence and absence of water steam was analyzed by a high temperature mass spectrometer. Only less than half of PH{sub 3}(g) is hydrolyzed, and CH{sub 3}Cl(g) also co-exist with HCl(g). After a certain duration of exposure, 1 ppm AsH{sub 3}(g), 0.5 ppm PH{sub 3}(g), and 2.5 ppm CH{sub 3}Cl(g) all caused some degree of degradation to the power density at 750 C. Whereas 1 ppm of H{sub 2}S(g) resulted in immediate performance loss. The mechanisms of degradation are mainly divided into two categories: surface adsorption effect (for S and Cl) and bulk reaction effect (for As and P). The controversies regarding the poisoning effect and mechanism of S are also discussed with the aid of ...

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The authors measured the absorption of CO{sub 2} in alkaline 0.5 M/0.5 M sodium carbonate/bicarbonate buffers containing either saccharose and sodium arsenite or saccharose and formaldehyde. Absorption enhancement increased upon increasing the concentration of either of the catalysts, but the joint action of the two was always less than the sum of their individual effects, the difference being a function of the acidities and concentrations of the catalysts and the pH of the carbonate/bicarbonate buffer solution

Science.gov (United States)

air traffic controllers at BOS tower and Terminal Radar Ap- .... Runway ) @ Runway. Buffer. Queue. Runway. Stochastic Delay. (M/1 server). (Runway to Fix). ,I, ...

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3-Quinuclidinyl benzilate (QNB) is a potent muscarinic antagonist that binds to muscarinic acetylcholine receptors. Iodination of QNB is difficult because it contains rings that are deactivated, while phenol rings are activated. The purpose of this research is to develop an appropriate method for the iodination of QNB at no-carrier-added concentrations of /sup 125/I/NaI. Phenol was chose as the test compound for direct iodination by adding chloramine T and nonradioactive sodium iodide to the phenol in a phosphate buffer and methanol system. A simple method to radioiodinate QNB at several concentrations was developed in situ in the presence of QNB, thallic trifluoroacetate /sup 125/I/NaI, /sup 127/I/NaI, and aluminium chloride. Using milligram amounts of QNB (7.12 x 10/sup -6/ moles), three reaction steps were involved: QNB was reacted with thallic trifluoroacetate at 60/sup 0/C for 24 hours, then radioactive /sup 125/I/NaI and aluminium chloride were added to the ...

British Library Electronic Table of Contents (United Kingdom)

The percolated or active triple phase boundary (TPB) length per unit volume of Ni-YSZ anode hollow fibers (HFs) containing 60wt.% initial NiO and a spatially varying microstructure were measured using a focused ion beam (FIB)-SEM technique. The measured values of contiguous TPB density were interfaced with a 2-D distributed finite element model of a hollow fiber solid oxide fuel cell. The model was applied to simultaneously solve the ionic and electronic charge balances in the electrodes, which were modelled as overlying continuum materials with effective electronic and ionic conductivities. The model was used to predict the effects of anode microstructure on the distribution of current density, and anode activation polarization. Active TPB lengths of 2.63-8.63 m^-^2 were measured for the ...

British Library Electronic Table of Contents (United Kingdom)

Summary 1. The EU -Nitrates Directive- (Directive 91/676/EEC) and the WFD (Water Framework Directive 2000/60/EEC) introduced a series of measures designed to reduce and prevent water pollution caused or induced by nitrates from agricultural sources. Therefore, there is an urgent requirement to control the nitrate concentration in freshwater. The objective of this paper was to verify the potential capacity of a specifically designed afforested riparian zone in removing the excess of nitrogen from river water. 2. A buffer zone was set with irrigation ditches, to produce a subsurface water flow carrying water from the study river through the buffer strip to drainage ditches. This experimental system enables the co-occurrence of two main processes: vegetation/microbial nitrogen uptake and deni...

British Library Electronic Table of Contents (United Kingdom)

The main objective of this work was to investigate the biosorption performance of unmodified and Cetylpyridinium chloride (CPC)-modified biomass of Penicillium YW 01 for Acid Blue 25 (AB 25). Maximum biosorption capacity of AB 25 onto CPC-modified biosorbent was 118.48mgg^-^1 under phosphoric-phosphate buffer with initial dye concentration of 200mgL^-^1 at 30^oC. The biosorption pattern of AB 25 onto unmodified biosorbent in aqueous solution and phosphoric-phosphate buffer was well fitted with both Langmuir and Freundlich isotherm models. While the equilibrium data of CPC-modified biosorbent in aqueous solution and phosphoric-phosphate buffer failed to fit the Freundlich isotherm model, indicating the monolayer biosorption formed onto CPC-modified biosorbent. The values of initial biosorpt...

UK PubMed Central (United Kingdom)

Testes of jellyfish Phialidium gregarium were fixed in 2 per cent OsO₄ in Veronal-acetate buffer at pH 7.4. Thin sections showed that in young spermatids the spindle fibers...Full Text Available

UK PubMed Central (United Kingdom)

Cd-binding protein was extracted from tomato roots and purified on QAE-Sephadex A-25 and on Sephadex G-75 in 1 molar KCl buffer. The protein preparation was light brown and contained predominantly Cd...Full Text Available

UK PubMed Central (United Kingdom)

Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate...Full Text Available

UK PubMed Central (United Kingdom)

1. Digital imaging and photometry were used in conjunction with the fluorescent Ca2+ indicator, Fura-2, to examine intracellular Ca2+ signals produced by depolarization of single adrenal chromaffin...Full Text Available

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A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

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This study reports on the physical-chemical behaviour of swelling di-octahedral clays (smectites) and their interaction with aqueous solutions and bacteria (Shewanella putrefaciens). Experimental results are presented for compacted clays, hydrated under confined volume conditions, using a new type of reaction-cell (the 'wet-cell' of Warr and Hoffman, 2004) that was designed for in situ X-ray diffraction (XRD) measurement. For comparison, dispersed clay systems were studied using standard batch solutions subjected to varying degrees of agitation. The combination of time-dependent in situ XRD measurements with gravimetric measurements and calculated diffraction patterns using the CALCMIX software (Plancon and Drits, 1999) allowed to successful quantification of the dynamics of water uptake and storage. This analytical procedure combined with published water vapour adsorption data enabled determination of the abundance of structured water layers, ...

British Library Electronic Table of Contents (United Kingdom)

One of the major limitations of the nickel (Ni) - yttria-stabilized zirconia (YSZ) anode support for solid oxide fuel cells (SOFC) is its low capability to withstand transients between reducing and oxidizing atmospheres (''RedOx'' cycle), owing to the Ni-to-NiO volume expansion. This work presents results on different anode supports fabricated by tape casting. Three compositions are prepared, as the outcome of a preceding design of experiment approach. The NiO proportion is 40, 50 and 60wt% of the anode composite. The anode support characteristics like shrinkage during sintering, in-situ conductivity at high temperature, electrochemical performance and tolerance against RedOx cycles have been measured. Performance up to 0.72Wcm^-^2 (0.62V, 800^oC) is recorded for the 60wt% NiO sample on sm...

Science.gov (United States)

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British Library Electronic Table of Contents (United Kingdom)

Layered carbon fiber mats have been prepared by layer-by-layer (LBL) electrospinning of polyacrylonitrile onto thin natural cellulose paper and subsequent carbonization. The layered carbon fiber mat has been proved to be a promising microbial fuel cell anode for high density layered biofilm propagation and high bioelectrocatalytic anodic current density.

UK PubMed Central (United Kingdom)

The values of the second dissociation constant pK₂ and related thermodynamic quantities of the ampholyte 3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO) have...Full Text Available

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To prove that two-layer, TBP-nitric acid mixtures can be safely stored in the Canyon evaporators, it must be demonstrated that a runaway reaction between TBP and nitric acid will not occur. Previous bench-scale experiments showed that, at typical evaporator temperatures, this reaction is endothermic and therefore cannot run away, due to the loss of heat from evaporation of water in the organic layer. However, the reaction would be exothermic and could run away if the small amount of water in the organic layer evaporates before the nitric acid in this layer is consumed by the reaction. Provided that there is enough water in the aqueous layer, this would occur if the organic layer is sufficiently thick so that the rate of loss of water by evaporation exceeds the rate of replenishment due to mixing with the aqueous layer. Bubbles containing ...

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This patent describes a method comprising applying a passivation layer of CaF{sub 2} to the surface of a superconductive ceramic oxide by evaporation. The CaF{sub 2} layer is effective to passivate the oxide surface without disrupting the superconductive properties.

Science.gov (United States)

A finite three-dimensional layer-by-layer photonic crystal with planar defects in a layer is shown to drastically modify the spontaneous emission rate of an embedded dipole. Finite-difference time-domain calculations with one quarter symmetric boundary condition and perfectly matched layer demonstrate the strong enhancement effects induced by the cavity resonance of defect modes and band-edge resonant modes. Simulation shows that the emission spectra are quite different when the position or polarization of the dipole is changed. Moreover, the extraction efficiency is calculated to observe the percentage of light leakage through a substrate.

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The variations of thickness of the ozone layer over Denmark in the 1978-1994 period based on monthly figures are presented. (CLS)

International Nuclear Information System (INIS)

Silicon layered structures containing porous silicon modified with various thermal treatments and epitaxial layers deposited on porous layers were studied with a number of complementary X-ray diffraction methods using synchrotron source. The methods of characterization included recording of rocking curves for reflections with various asymmetry as well as projection, section and micro-Laue topography. It was found that oxidizing and sintering of porous silicon seriously modified the strains in the porous layer and in some cases even inverting the sense of strain with respect to that in initially formed porous layer. Consequently the deposited epitaxial layer usually was not laterally coherent with the substrate. Some of investigated layers were not stable in time and after few months period exhibited significant lost of coherence of porous ...

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The influence of small amounts of alloying elements (0.36% Cu and 0.47% Cr) on the semiconducting properties of passive films formed on weathering steels was investigated either in tetraborate/boric acid buffer solution (pH 9.2) or artificial atmospheric environment (SO{sub 2}-containing environment). The electrochemical behaviour was assessed by potentiodynamic polarisation, capacitance measurements and photoelectrochemistry. The chemical characterisation of the films was carried by Auger electron spectroscopy. The polarization results obtained in the buffer solution show that the addition of chromium decreases the passive current density. The capacitance results show that the films behave as an n-type semiconductor with shallow and deep donor levels situated in the forbidden gap. The presence of copper seems to affect the density of the shallow and of the deep donor levels in the forbidden gap, and as chromium, it also decreases the doping ...

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The Thai natural rubber economy is described in the context of the world rubber market. An econometric model is estimated for 15 structural equations; it includes the Thai, US, and rest-of-the-world rubber economies. Several simulation experiments are analyzed for the period from 1984 to 1995. Impact and dynamic multipliers are reported for major endogenous variables in response to changes in US GDP, world crude oil price, Thai replanting cess tax and Thai natural rubber production. A 1%, one-time increase in the US GDP has a positive effect on the Singapore natural rubber price. A world crude oil price decline shock has a negative effect in both the short-run and the long-run. The INRO buffer stock stabilization policy as well as alternative domestic Thai policies of market intervention are analyzed. The simulation results show that buffer stock management which allows a price band of +/-20% around the price target has the most stabilized ...

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Research highlights: {yields} The polarization curve of 316L SS possesses five turning potentials in passive region. {yields} Films formed at turning potentials perform different electrochemical and semiconductor properties. {yields} Dissolutions and regenerations of passive film at turning potentials are obtained by AAS and XPS. {yields} Turning potentials appearing in passive region are ascribed to the changes of the compositions of the passive films. - Abstract: The passivity of 316L stainless steel in borate buffer solution has been investigated by Mott-Schottky, atomic absorption spectrometry (AAS) and X-ray photoelectron spectroscopy (XPS). The results indicate that the polarization curve in the passive region possesses several turning potentials (0 V{sub SCE}, 0.2 V{sub SCE}, 0.4 V{sub SCE}, 0.6 V{sub SCE} and 0.85 V{sub SCE}). The passive films formed at turning potentials perform different electrochemical and semiconductor properties. Further, the ...

International Nuclear Information System (INIS)

A novel Ni and Cu-free Zr-based bulk metallic glass (BMG) system with enhancement of glass-forming ability (GFA) and bio-corrosion resistance was prepared by copper mold casting by the addition of Ag. It was found that the addition of Ag can considerably enhance the glass-forming ability, as indicated by the increase of the critical glass dimension from 3 mm diameter of the ternary system to over 10 mm in the alloy of Zr_5_3Co_1_8_._5Al_2_3_._5Ag_5. The bio-corrosion behaviors of the Zr-based BMGs in phosphate buffered solution (PBS) were investigated by electrochemical polarization at 310 K. It was found that the addition of appropriate amount of Ag can enhance the corrosion resistance of the BMGs. The X-ray photoelectron spectroscopy (XPS) indicated that the formation of an Al_2O_3-enriched passive film is mainly responsible for the high corrosion resistance of Ag-bearing alloy in phosphate buffered solution.

Energy Technology Data Exchange (ETDEWEB)

The Data Acquisition System for the CDMS II dark matter experiment was designed and built when the experiment moved to its new underground installation at the Soudan Lab. The combination of remote operation and increased data load necessitated a completely new design. Elements of the original LabView system remained as stand-alone diagnostic programs, but the main data processing moved to a VME-based system with custom electronics for signal conditioning, trigger formation and buffering. The data rate was increased 100-fold and the automated cryogenic system was linked to the data acquisition. A modular server framework with associated user interfaces was implemented in Java to allow control and monitoring of the entire experiment remotely.

Energy Technology Data Exchange (ETDEWEB)

A procedure for high level tritium labelling at the C2-H position of adenosine 5`-triphosphate ([2-{sup 3}H]-ATP, 1), based on the tritiodehalogenation reaction of 2-bromoadenosine 5`-triphosphate (2) has been elaborated. This precursor was prepared in a six-step synthesis from guanosine. The tritiodehalogenation of (2) for three hours over palladium oxide in phosphate buffer yielded tritium labelled ATP with high specific activity, in good chemical yield. (author).

CERN Document Server

In this paper, we present FASE (Faster Asynchronous Systems Evaluation), a tool for evaluating the worst-case efficiency of asynchronous systems. The tool is based on some well-established results in the setting of a timed process algebra (PAFAS: a Process Algebra for Faster Asynchronous Systems). To show the applicability of FASE to concrete meaningful examples, we consider three implementations of a bounded buffer and use FASE to automatically evaluate their worst-case efficiency. We finally contrast our results with previous ones where the efficiency of the same implementations has already been considered.

Energy Technology Data Exchange (ETDEWEB)

This executive summary presents the motivation, structure, objectives, methodologies and results of the first stage of the international DECOVALEX project - DECOVALEX I (1992-1995). The acronym stands for Development of Coupled Models and their Validation against Experiment in Nuclear Waste Isolation, and the project is an international effort to develop mathematical models, numerical methods and computer codes for coupled thermo-hydro-mechanical processes in fractured rocks and buffer materials for geological isolation of spent nuclear fuel and other radioactive wastes, and validate them against laboratory and field experiments. 24 refs.

Science.gov (United States)

A colony PCR technique was applied for both genomic and chloroplast DNA in the green microalgae Chlorella. Of five different lysis buffers, Chelex-100 was superior for DNA extraction, PCR and DNA storage. It also was insensitive to variations in cell density. The conditions established for an improved PCR formulation are applicable for screening of genetically-engineered transformants as well as bioprospecting of natural microalgal isolates. Besides multiple Chlorella species, we also demonstrate the efficacy of Chelex-100 for colony PCR with a number of other microalgal strains, including Chlamydomonas reinhardtii, Dunaliella salina, Nannochloropsis sp., Coccomyxa sp., and Thalassiosira pseudonana. PMID:21431847

Energy Technology Data Exchange (ETDEWEB)

The preliminary design of the read-out system for the GEM (Gammas, Electrons, Muons) detector at the Superconducting Super Collider is presented. The system reads all digitized data from the detector data sources at a Level 1 trigger rate of up to 100 kHz. A total read-out bandwidth of 40 GBytes/s is available. Data are stored in buffers that are accessible for further event filtering by an on-line, processor farm. Data are transported to the farm only as they are needed by the higher-level trigger algorithms, leading to a reduced bandwidth requirement in the Data Acquisition System.

International Nuclear Information System (INIS)

The structure of the layers formed on a silver electrode by the adsorption of pyridine, Cl"-, CN"- and SO_4"2"- is discussed. A comparison of the amount of the species adsorbed with their Raman spectra shows that there is no simple relation between the species concentration and the enhancement of the Raman intensity. Furthermore, the inhomogeneity of the layers is shown by Raman microscopy observations. These results lead the authors to propose the formation of a new species stabilized in the colloidal silver layer. The Raman enhancement could be explained by the existence of a resonance effect. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

Governments around the world will soon make decisions on policies that could determine the fate of the ozone layer-the Earth's shield from harmful ultraviolet radiation. The Vienna Convention for the Protection of the Ozone Layer, signed on March 22, 1985, created a framework for scientific cooperation and information exchange that will form the basis for a protocol for controlling substances thought to threaten the ozone layer. As of mid-1987, 29 countries had signed the Convention, including the major producers and users of chlorofluorocarbons (CFCs), the most important of suspect chemicals.

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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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.).

International Nuclear Information System (INIS)

Tumor imaging using radioiodinated monoclonal antibodies (Mab) suffered from rapid in vivo deiodination. This problem can be circumvented by covalent attachment of a bifunctional chelating group to the Mab followed by chelation with a suitable cationic radionuclide such as In-111. Competition of trace metal contaminants with In-111 for chelating sites, however, is known to lower the labeling yield. Since commercially available reagents may be contaminated with other trace metal ions, the effect of trace metals on Mab-DTPA chelation and the possibility of masking the trace metal effect on the In-111 labeling of Mab-DTPA were, therefore, investigated. Labeling yield of 93% was obtained when 1 mg (20mg/ml) of Mab F(ab')/sub 2/-DTPA (protein to DTPA ratio of --1) was allowed to incubate with 3 mCi In-111 in 2 ml acetate buffer (0.5M, pH 5.5) for 30 min. The yield was drastically decreased to 13-76% when the reactions were carried out with the addition of 1-2 #mu#g of ...

Energy Technology Data Exchange (ETDEWEB)

We have grown ferroelectric Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub 3} (PLZT) films on platinized silicon and LaNiO{sub 3}-buffered nickel substrates by chemical solution deposition using a sol-gel process based on acetic acid chemistry. The following measurements were obtained under zero-bias field: relative permittivity of {approx}960 and dielectric loss of {approx}0.04 on the PLZT film grown on Pt/Si substrates, and relative permittivity of {approx}820 and dielectric loss of {approx}0.06 on the PLZT film grown on LNO-buffered Ni substrates. In addition, a relative permittivity of 125 and dielectric loss of 0.02 were measured at room temperature under a high bias field of 1 x 10{sup 6} V/cm on PLZT deposited on LNO-buffered nickel substrate. Furthermore, a steady-state leakage current density of {approx}8.1 x 10{sup -9} A/cm{sup 2} and mean breakdown field strength of 1.7 x 10{sup 6} V/cm were measured at ...

International Nuclear Information System (INIS)

The authors present an investigation of structural changes occurring in bilayer stacks with crystalline columnar growth when one of the layers is substituted by layers known to grow amorphous. In Co/Cu multilayers the Co layers were substituted by CoZr layers of varying Zr content and layer thickness. Structural characterization was performed by transmission electron microscopy (TEM). They show that the amorphization of the CoZr layers leading to a destruction of the columnar growth depends both on the Zr content and on the thickness of the CoZr layers. Additionally a change to textured growth with a normal to the substrate occurs with increasing Zr content. They explain their observations by a simple picture based on the hard sphere model.

Energy Technology Data Exchange (ETDEWEB)

A route, as followed by ECN, is described for development of SiN{sub x}:H layers deposited by microwave (MW) PECVD, which are suited for surface and bulk passivation of mc-Si solar cells. First research was focussed on surface passivation and this resulted in the development of SiN layers that were Si-rich and where the hydrogen is mainly bonded to silicon atoms. A disadvantage of such Si-rich layers is their large absorption at shorter wavelengths, which make them unsuitable as front side AR coatings. Further, these layers appeared to be less suitable for bulk passivation. The next step therefore was the development of SiN layers for bulk passivation. For good bulk passivation of solar cells by means of a thermal anneal of the SiN layers, we found that SiN layers with high N-H bonding concentrations are required. Fine-tuning of the ...

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

Layer-by-layer formation for #pi#-conjugated azomethine multilayers bonded on substrates was investigated. The multilayers were synthesized using ethanol (EtOH) and dichloromethane (DCM) as reaction solvents. The multilayer characteristics were analyzed using UV-vis absorption spectroscopy, ellipsometric thickness, and atomic force microscopy. The absorption spectra and ellipsometric thicknesses of multilayers formed using EtOH and DCM were compared. The results indicate that EtOH is more suitable than DCM for such layer-by-layer formation. In addition, bandgaps estimated from the absorption edge of multilayers were investigated. The results indicate that the bandgap decreases as the number of benzene rings contained in the molecular chain of the multilayer increases. Also, a multilayer with four benzene rings bonded on a substrate had a bandgap close to that of a polymer with a similar chemical structure.

Energy Technology Data Exchange (ETDEWEB)

Pulsed DC-plasma nitriding has been applied to form nitride layer having only a diffusion layer. The discharge current with the variation of discharge gases is proportional to the intensity of N{sub 2}{sup +} peak in optical emission spectroscopy during the plasma nitriding. The discharge current, microhardness in surface of substrate and depth of nitride layer increased with the ratio of N{sub 2} to H{sub 2} gas in discharge gases. When the ratio of N{sub 2} to H{sub 2} is lower than 60% in the discharge gases, high microhardness value of 1100Hv nitride layer which contains no compound layer has been formed. (author). 20 refs., 6 figs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

In the present work, the plasma nitriding behavior of a nickel based dental alloy was investigated. Plasma nitriding experiments carried out under constant gas mixture (15% H2?85% N2) for different process parameters including time (4, 6, 10, and 20?h) and temperature (400, 450, 500, and 550??C). Depending on nitriding parameters, it was found that triple or double layers formed on the surface of the samples. Increasing of treatment time and temperature has resulted in a double layer. ?N1 layer was in formed all nitrided samples. However, ?N2 layer is formed only at low temperatures and in short times. Layer growth of nickel based alloys increases until a critical time or a critical temperature reached. Above these critical values, it is observed that the layer thickness decreases. It was ...

Energy Technology Data Exchange (ETDEWEB)

Developing safe, reliable, cost-effective, and efficient hydrogen-electricity co-generation systems is an important step in the quest for national energy security and minimized reliance on foreign oil. This project aimed to, through materials research, develop a cost-effective advanced technology cogenerating hydrogen and electricity directly from distributed natural gas and/or coal-derived fuels. This advanced technology was built upon a novel hybrid module composed of solid-oxide fuel-assisted electrolysis cells (SOFECs) and solid-oxide fuel cells (SOFCs), both of which were in planar, anode-supported designs. A SOFEC is an electrochemical device, in which an oxidizable fuel and steam are fed to the anode and cathode, respectively. Steam on the cathode is split into oxygen ions that are transported through an oxygen ion-conducting electrolyte (i.e. YSZ) to oxidize the anode fuel. The dissociated hydrogen and residual steam are exhausted from the SOFEC cathode and ...

UK PubMed Central (United Kingdom)

The purpose of this study was to determine the thickness of the macula and the retinal nerve fiber layer (RNFL) in Japanese subjects by Stratus optical coherence tomography (OCT), and to compare the...Full Text Available

UK PubMed Central (United Kingdom)

Hydrolytic exoenzymes as indicators of metabolically active bacteria were investigated in four consecutive sapropel layers collected from bathyal sediments of the eastern Mediterranean Sea. For comparison,...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A prototype detector based on the inclined boron layer principle is introduced. For typical measurement conditions at the Liquids Reflectometer at the Spallation Neutron Source, its count rate capability is shown to be superior to that of the current detector by nearly two orders of magnitude.

Energy Technology Data Exchange (ETDEWEB)

In this work, the silicon oxynitride layer was studied as a tunneling layer for non-volatile memory application by fabricating low temperature polysilicon thin film transistors on glass. Silicon wafers were oxynitrided by only nitrous oxide plasma under different radio frequency powers and plasma treatment times. Plasma oxynitridation was performed in RF plasma using inductively coupled plasma chemical vapor deposition. The X-ray energy dispersive spectroscopy was employed to analyze the atomic concentration ratio of nitrogen/oxygen in oxynitride layer. The oxynitrided layer formed under radio frequency power of 150 W and substrate temperature of 623 K was found to contain the atomic concentration ratio of nitrogen/oxygen as high as 1.57. The advantage of high nitrogen concentration in silicon oxide layer formed by using nitrous oxide plasma was investigated by capacitance-voltage ...

Energy Technology Data Exchange (ETDEWEB)

A duplex surface treatment technique based on calorizing and plasma nitriding was developed to improve the wear and oxidation resistance of H13 steel at high temperatures. The effects of the relative thickness of the calorized layer to the depth of plasma nitriding on the wear and oxidation properties at temperatures up to 900 C were investigated in this work. High-temperature wear tests were performed at 500 C with dry conditions in open air using a ball-on-disk type tribotest machine. Isothermal oxidation tests were performed at 900 C for up to 100 h under controlled atmosphere. The results indicated that the specimens with a calorized layer as an intermediate phase between the surface duplex layer and the base metal showed higher wear and oxidation resistance than the specimens with a nitrided layer alone. During exposure to elevated temperatures, the aluminum in the calorized ...

UK PubMed Central (United Kingdom)

The mammalian neocortex consists of six layers. By contrast, the reptilian and avian cortices have only three, which are believed to be equivalent to layers I, V and VI of mammals. In mammals, the majority...Full Text Available

Science.gov (United States)

... This pinhole process may be similar to the formation of an oxide layer in aluminum electrolytic capacitors immersed in a borax solution. ...

Energy Technology Data Exchange (ETDEWEB)

Cesium recovery from the polluted layers in the 1/3 scale hydrogen negative ion source for LHD-NBI system has tested. It was found, that the cesium recovery can be produced by additional discharges as from the cesium layer, aged by tungsten and residual gas, so as from the cesium layers, polluted by an occasional water leak. The highest cesium recovery to NI production was produced by a xenon arc, while glow discharge and arcing in hydrogen were less effective. The mechanism of recovery is the ejection of cesium from the underlying enriched layer by the arc and its transport to the surface. (author)

International Nuclear Information System (INIS)

With the aim of optimizing the nitriding process parameters (temperature and gas mixture ) experimental studies of the plasma nitriding of Ck 15 steel were carried out, using a D. C. glow discharge. Nitriding treatments were performed at 450, 500 and 550 and N_2/H_2 volume ratio of 3/1, 1/1 and 1/3 for 5 hours. Nitriding treatment produces modified surface layer consisting of an outer compound layer and an inner diffusion layer.The plasma nitriding of Ck 15 produce single white layer consisting of #gamma#-(Fe_4N).

British Library Electronic Table of Contents (United Kingdom)

There is investigated the role of polymer layers on the metal surface of a fine filler in the formation of a PVC system with electrophysical properties. It is shown that a physicochemical polymer modification takes place under the surface active center influence. Thus, the surface layer properties (density and geometrical characteristics) differ from the PVC ones. The correlation between the electrophysical properties of the PVC composite and the surface layer in the range of the fine copper fraction of 0?11.3 vol % at E ? 106 V m?1 and a frequency response of 20?2 ? 105 Hz is determined. An explanation of the investigated relation is presented.

Science.gov (United States)

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Energy Technology Data Exchange (ETDEWEB)

The paper describes an analytical study of two parallel-flowing boundary layers of free and forced convection modes on the facing sides of a vertical thin wall. The two layers are analyzed separately within the framework of boundary layer theory, and coupled by the matching conditions at wall. Numerical data are obtained for a wide range of a dimensionless conjugation parameter {zeta} relating the heat transfer effectiveness of two convection modes. Based on these data, an expression for calculating the conjugate mean Nusselt number as a function of {zeta}-parameter is found by means of a curve-fitting method. (orig.)

Energy Technology Data Exchange (ETDEWEB)

In contrast to plants based on formed coal where, for the purposes of calculating sorbent volume, only one activated charcoal design can be used in a filter layer, powder sorbent technology enables two variations to be used. This can be either a mixture of a number of different activated charcoal forms in one and the same filter layer, or the combination of a number of filter layers on top of each other, each containing a different activated charcoal form, in one and the same construction unit.

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 ...

CERN Document Server

The paper describes design and practical realization of an internal communication layer referred to as the Internal Interface (II). The system was realized for the RFC Muon Trigger of the CMS experiment. Fully automatic implementation of the communication layer is realized in the FPGA chips and in the control software. The methodology of implementation was presented in the description form of the interface structure from the sides of hardware and software. The examples of the communication layer realizations were given for the RFC Muon Trigger.

Energy Technology Data Exchange (ETDEWEB)

The properties of Mn-doped GaAs layers grown by laser deposition were investigated with measurements of Hall effect and magneto-optical Kerr effect (MOKE). The electrical and magnetic parameters of the layers were defined by growth temperature and quantity of sputtered Mn. It was shown that room-temperature ferromagnetism is revealed by MOKE and, after ruby laser 25 ns pulse annealing, by Hall effect measurements.

Energy Technology Data Exchange (ETDEWEB)

Visible laser light output from an electrically injected vertical cavity surface emitting laser (VSCEL) diode is enabled by the addition of phase-matching spacer layers on either side of the active region to form the optical cavity. The spacer layers comprise InAlP which act as charge carrier confinement means. Distributed Bragg reflector layers are formed on either side of the optical cavity to act as mirrors. 5 figs.

Energy Technology Data Exchange (ETDEWEB)

A study has been made of the passive film remaining over pits on stainless steel using a high resolution transmission electron microscope. Type 305 stainless steel was passivated in a borate buffer solution and pitted in ferric chloride. Passive films formed at 0.2 V relative to a saturated calomel electrode were found to be amorphous. Films formed at higher potentials showed only broad diffraction rings. The passive film was found to cover a remnant lacy structure formed over pits passivated at 0.8 V. The metallic strands of the lace were roughly hemitubular in shape with the curved surface facing the center of the pit.

British Library Electronic Table of Contents (United Kingdom)

Terror management theory (TMT) proposes that people who are reminded of their mortality should be motivated to defend their cultural worldview. Studies 1 and 2 examined whether the TMT worldview defence-buffering effect found in Western cultures could be generalized to Asians in Taiwan. No such effect was found in the present studies. This non-significant result was robust when either a stronger distraction task was used (study 1) or when a subliminal manipulation of mortality salience was utilized (study 2). A meta-analysis, including 24 TMT experiments in East Asia, was also conducted (study 3). The average effect size (d = 0.11, r = 0.055) of worldview defence among these experiments was not significantly different from zero. Study 4 found that mortality salience manipulation also did n...

International Nuclear Information System (INIS)

HLW disposal is one of the largest issue to utilize Nuclear power safely. In the past study, the concept, which buffer materials and Overpacked waste were transported into underground respectively, have shown. The concept of pre-assembled engineered barrier has advantage to simplify the logistics and emplacement procedure, however there are difficulties to support heavy weight of pre-assembled package by equipment under the condition of little clearance between tunnel and package. In this study, Combination of air bearing and two degree-of-freedom wheels were suggested for transportation, and air jack was suggested for unloading and emplacement system. Also, whole system for transportation and emplacement procedure was designed, and Scale model test was examined to evaluate the feasibility of these concept and functions. (author)

Energy Technology Data Exchange (ETDEWEB)

The effect of Al/sup 3 +/, Fe/sup 3 +/, Ca/sup 2 +/, and Mg/sup 2 +/ ions and of pH on the two-dimensional shear modulus of stearic acid spread on a water substrate was determined. A large shear modulus was displayed by the films when the subphase contained Al/sup 3 +/ and Fe/sup 3 +/ ions at the self-buffered pH. With Fe/sup 2 +/ dissolved in the subphase, the film displayed a viscous relaxation when strained but no residual stress was observed. No effect was observed with the Ca/sup 2 +/ or Mg/sup 2 +/. Reducing the pH value in the subphase with the trivalent ions caused the shear modulus to disappear. The observations are interpreted in terms of hydrogen bonding.

British Library Electronic Table of Contents (United Kingdom)

Purpose The mangroves of New Caledonia, in the south Pacific, act as a buffer between a lagoon of more than 20,000?km2 and the island, which is characterized by ultramafic rocks and lateritic soils that are exploited for their richness in heavy metals. We will provide a better understanding of the redox conditions, and of heavy metal distributions in mangroves receiving shrimp farm effluents. Materials and methods Samples were collected from four areas defined in terms of vegetation composition: a salt flat, an Avicennia marina forest, in which effluents are released; a Rhizophora stylosa forest, and a dead Rhizophora forest. They were collected during times of maximum effluent release. Some measurements on pore water were also done during a period without effluent. Cores (70?cm deep) were...

British Library Electronic Table of Contents (United Kingdom)

The present study was carried out to exploit the feasibility of using polymeric nanosponges as an alternative carrier for targeting econazole nitrate (EN) to the skin through topical hydrogel formulation. Nanosponges prepared by emulsion solvent diffusion method were evaluated for various physicochemical parameters and in vitro drug release. The nanosponges of EN were discrete free flowing nanosized particles with perforated orange peel like morphology as visualized by SEM. The nanosponge formulated using PVA:EC (3:2) displayed highest in vitro release after 12 ?h in phosphate buffer (pH 6.8) that fitted matrix model. Selected nanosponge was formulated as Carbopol 934 NF hydrogel using varying concentrations of permeation enhancers propylene glycol and N-methyl-2-pyrrolidone. The EN nanosp...

British Library Electronic Table of Contents (United Kingdom)

Analysis reproducibility and detection sensitivity of capillary electrophoresis (CE) are often questioned by applied scientists, which has hindered its application as a routine method. To address these issues, a simple, precise, and reproducible dynamic coating method was developed by applying carboxymethyl chitosan (CMC) dynamic coating on fused silica capillary. The proposed coating was accomplished by simply rinsing the capillary with CMC solution for 1?min in between runs, with no regeneration procedure or buffer additives needed. Electroosmotic flow could be well controlled by adjusting the pH of background electrolyte, and the adsorption of analytes onto the capillary inner wall was effectively eliminated. The main parameters of the coating condition were optimized, and extensive app...

British Library Electronic Table of Contents (United Kingdom)

Abstract Dispersions of single-walled carbon nanotubes (SWNTs) in various surfactant solutions have been systematically evaluated as additives in MEEKC. The compounds examined were catechins, phenolic acids, and flavonoids. Compared with zwitterionic and neutral surfactants, the addition of anionic dispersion seemed to be better at separating the three types of analytes in microemulsion system. In order to achieve low operating currents, an in situ-synthesized surfactant system based on the combination of a long-chain alkyl acid with an organic base was used in MEEKC. The optimized buffer contained 0.5% (57-mM) ethyl acetate, 0.6% (30-mM) lauric acid, 4.0% (666-mM) propanol, 50-mM Tris solution, and 4.5-mg/L the dispersion of SWNTs. Under optimized conditions, the established method was ap...

Energy Technology Data Exchange (ETDEWEB)

The kinetics of passive film formation on iron in borate buffer solution has been studied at different anodic potentials. The process of film growth has been found to occur in four distinct stages. About 80-90% of the total film thickness formed in 1h grows during the initial two stages which last for only 1-3s (depending upon potential). The electric field strength across the film is not constant but decreases with progressing film growth. The thickness of the film determined ellipsometrically is less than that calculated from the electric charge consumed. The process of anodic film formation is accompanied by the dissolution of iron which occurs over the whole range of potentials.

British Library Electronic Table of Contents (United Kingdom)

Amino-rich polymeric coatings are widely used in biomedical applications, since they promote adsorption of diverse biomolecules or facilitate cell growth. As a consequence, there is a growing interest in fabrication of such coatings that is focused predominantly on the optimization of the deposition process in terms of high density of primary amino groups. In addition, the nature of biomedical applications requires also sufficient stability of the films in aqueous environments. This aspect is investigated in this contribution. In particular, the effect of water and phosphate buffer saline on the coatings prepared by RF magnetron sputtering of Nylon 6,6 in Ar/N2 and N2/H2 gas mixtures is evaluated. The samples exposed to liquids are characterized by various diagnostic methods and their prop...

British Library Electronic Table of Contents (United Kingdom)

Mentougou District acts as a crucial component in the ecological buffer in western Beijing mountainous areas, Beijing, China. Using two Landsat MSS/TM images acquired on July 14, 1979 and July 23, 2005, the vegetation coverage of Mentougou District was calculated based on normalized difference vegetation index and spectral mixture analysis (NDVI-SMA) model. Its temporal and spatial changes were analyzed according to digital elevation model (DEM) image, social and economic data. The results showed that the vegetation coverage decreased from 76.4% in 1979 to 72.7% in 2005. Vegetation degradation was probably the result of human disturbance, such as outspreading of resident areas, and coal and stone mining activities, while vegetation restoration might be contributed by the combined effects o...

Energy Technology Data Exchange (ETDEWEB)

In the Ti-Si-C and Ti-Si-C-N systems, metastable layers were precipitated by means of non-reactive magnetron sputtering of hot-pressed two-phase TiC/SiC and TiN/SiC targets with 20 mole% and 50 mole% SiC. The preparation parameters were varied as follows: ion bombardment during precipitation (bias sputtering), substrate temperature, and annealing times when annealing amorphous 50%:50% TiC/SiC and 50%:50% TiN/SiC layers. Sputtering of targets containing 20% SiC was found to result in monophase fcc layers (NaCl structure). This was documented on the basis of X-ray and electron diffraction patterns. Direct precipitation of targets with 50 mole% SiC resulted in amorphous layers. Increasing the ion bombardment during accretion, raising the substrate temperature, and annealing amorphous 50%:50% TiC/SiC and 50%:50% TiN/SiC (layers precipitated directly) resulted in the crystallization of ...

Energy Technology Data Exchange (ETDEWEB)

Low residual stress silicon oxynitride thin films are investigated for use as a replacement for silicon dioxide (SiO{sub 2}) as sacrificial layer in surface micromachined microelectrical-mechanical systems (MEMS). It is observed that the level of residual stress in oxynitrides is a function of the nitrogen content in the film. MEMS film stacks are prepared using both SiO{sub 2} and oxynitride sacrificial layers. Wafer bow measurements indicate that wafers processed with oxynitride release layers are significantly flatter. Polycrystalline Si (poly-Si) cantilevers fabricated under the same conditions are observed to be flatter when processed with oxynitride rather than SiO{sub 2} sacrificial layers. These results are attributed to the lower post-processing residual stress of oxynitride compared to SiO{sub 2} and reduced thermal mismatch to poly-Si.

Energy Technology Data Exchange (ETDEWEB)

Particle simulation studies of collisionless driven reconnection in an open system are presented. Collisionless reconnection evolves in two steps in accordance with the formation of two current layers, i.e., an ion current layer in the early ion phase and an electron current layer in the late electron phase. After the electron current layer is formed inside the ion current layer, the system relaxes gradually to a steady state when convergent plasma flow is driven by an external electric field with a narrow input window. On the other hand, when the convergent plasma flow is driven from the wide input window, magnetic reconnection takes place in an intermittent manner, due to the frequent formation of magnetic islands in the vicinity of neutral sheet. (author)

Energy Technology Data Exchange (ETDEWEB)

The role of the unsaturated properties of sand as a drainage layer in a composite liner system for landfills is investigated. The effect of the unsaturated properties of coarse-grained soil on contaminant migration was evaluated by means of a series of simulations using a one-dimensional model of a two- and a three-layer soil liner system for advection and diffusion, respectively. The results showed that under seepage conditions, the effect of an unsaturated sand layer on the advancement of the concentration front was quite insignificant. The arrival time of the C/C{sub o} = 0.5 concentration front increased from 651 days for the case with no sand layer to approximately 951 days for the case with a 1.0-m sand layer. A steady-state flow condition was ultimately established in the sand, and this fact suggests that the capillary action might not be effective. For diffusion, the arrival ...

International Nuclear Information System (INIS)

["3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37"0C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as #alpha#-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic ...

Energy Technology Data Exchange (ETDEWEB)

The hypothesis that intracellular Ca/sup 2 +/ is an essential component of the intracellular mechanism of insulin action in the adipocyte was evaluated. Cells were loaded with the Ca/sup 2 +/ chelator quin-2, by preincubating them with quin-2 AM, the tetrakis(acetoxymethyl) ester of quin-2. Quin-2 loading inhibited insulin-stimulated glucose transport without affecting basal activity. The ability of insulin to stimulate glucose uptake in quin-2-loaded cells could be partially restored by preincubating cells with buffer supplemented with 1.2 mM CaCl/sub 2/ and the Ca/sup 2 +/ ionophore A23187. These conditions had no effect on basal activity and omission of CaCl/sub 2/ from the buffer prevented the restoration of insulin-stimulated glucose uptake by A23187. Quin-2 loading also inhibited insulin-stimulated glucose oxidation and the ability of insulin to inhibit cAMP-stimulated lipolysis without affecting their basal activities. Incubation of ...

Energy Technology Data Exchange (ETDEWEB)

A brief review and assessment of field measurement programs that provide data for mixed layer diffusion research is presented. The majority of programs emphasize either the meteorological aspects of the mixed layer or plume characterization. Few programs are available that provide the complimentary blend of plume and appropriate meteorological measurements needed to adequately validate mixed layer diffusion theory. Three major U.S. EPA (Environmental Protection Agency) field programs that provide data bases for model development and validation of mixed layer diffusion processes are described and discussed in more detail. The Regional Air Pollution Study (RAPS) focused on measurements of surface and mixed layer turbulent transport processes in the urban environment. The Tennessee Plume Study (TPS) obtained a database with coincident measurement of boundary layer ...

Energy Technology Data Exchange (ETDEWEB)

The present work describes the surface improvement and biocompatibility of TiAl{sub 24}Nb{sub 10} intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to ...

International Nuclear Information System (INIS)

We have developed a chemical process for incorporating copper into indium gallium selenide layers with the goal of creating a precursor structure for the formation of copper indium gallium diselenide (CIGS) photovoltaic absorbers. Stylus profilometry, EDX, Raman spectroscopy, XRD and SIMS measurements show that when indium gallium selenide layers are immersed in a hot copper chloride solution, copper is incorporated as copper selenide with no increase in the thickness of the layers. Further measurements show that annealing this precursor structure in the presence of selenium results in the formation of CIGS and that the supply of selenium during the annealing process has a strong effect on the morphology and preferred orientation of these layers. When the supply of Se during annealing begins only once the substrate temperature reaches ? 400 deg. C , the resulting CIGS layers are ...

Energy Technology Data Exchange (ETDEWEB)

In order to enhance the performance of CMOS transistors, embedded epitaxial layers of Si:C can be used. In the present work, Si:C layers with Carbon contents up to 1.9 at-% and in-situ Phosphorus doping up to 4 x 10{sup 20}At/cm{sup 3} have been investigated. Due to the low solubility of Carbon in Silicon (0.0004 at.-% at the melting point), all layers considered in this work are metastable and tend to relax. Since it is crucial to the application to retain the strain of those layers, the responsible mechanisms must be understood. The relaxation during thermal treatment was studied by high resolution X-ray diffraction and was found to behave differently, depending on Carbon content and Phosphorus doping concentration. In this work, we propose a relaxation mechanism based on a kick-out reaction of substitutional Carbon which is accelerated by Phosphorus content through transient enhanced diffusion. We ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

It has been clarified by the present authors, based on the plasma nitriding of Fe-Cr alloys and Fe-Ti alloys carried out at the temperature under 550{degree}C hitherto, that an internal nitriding layer is formed due to the fine dispersion of the particles of Cr nitride and Ti nitride in {gamma}{prime} Fe4N layer on the specimen surface. In this study, the plasma nitriding of Fe-Cr alloys are carried out at 650{degree}C, and the effects of the solute (Cr) content on the structures, nitride and the thickness distribution are examined. The main results obtained therefrom are indicated hereafter. In accordance with the observation on the cross-sectional structure of the alloys, only the nitriding layer deduced as the dispersion and precipitation of the particles of Cr nitride from {alpha}-Fe of the mother phase is formed, while {gamma}{prime}-Fe4N layer, which is found at the temperature under 550{degree}C, ...

Science.gov (United States)

We study the emission zone in a single-layer polymer light-emitting diode. The emission zone is found by studying the angular distribution of the electroluminescence. The emission is modeled by accounting for optical interference. We account for birefringence of the anode layer in our model. The active polymer was, however, found to be isotropic. The anode consists of a single-layer of the conducting polymer complex poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonate) (PEDOT-PSS), with enhanced conductivity. As a cathode we use plain aluminum. By using only PEDOT-PSS we avoid having a thin metal layer or indium-tin-oxide as the anode in the path of the escaping light. The active material is a substituted polythiophene with excellent film forming properties. A comparison between the experimental and calculated angular distribution of light emission from a single-layered ...

International Nuclear Information System (INIS)

Thin passive films formed on highly corrosion-resistant type-312L stainless steel, containing 20 mass% chromium and 6 mass% molybdenum, in 2 mol dm-3 HCl solution at 293 K have been analyzed by glow discharge optical emission spectroscopy (GDOES). The stainless steel does not suffer pitting corrosion even in this aggressive solution, showing a wide passive potential region. The depth profiles obtained clearly show a two-layer structure of the air-formed and passive films: an outer iron-rich layer and an inner layer highly enriched in chromium. Alloy-constituting molybdenum is deficient in the inner layer of the passive films and is enriched in the outer layer, particularly at the active dissolution potential. The molybdenum species in the outer layer may retard the active dissolution of stainless steel, promoting the formation of stable passive films highly ...

CERN Document Server

We present an analytical model for jets in Fanaroff & Riley Class I (FRI) radio galaxies, in which an initially laminar, relativistic flow is surrounded by a shear layer. We apply the appropriate conservation laws to constrain the jet parameters, starting the model where the radio emission is observed to brighten abruptly. We assume that the laminar flow fills the jet there and that pressure balance with the surroundings is maintained from that point outwards. Entrainment continuously injects new material into the jet and forms a shear layer, which contains material from both the environment and the laminar core. The shear layer expands rapidly with distance until finally the core disappears, and all of the material is mixed into the shear layer. Beyond this point, the shear layer expands in a cone and decelerates smoothly. We apply our model to the well-observed FRI source 3C31 ...

Science.gov (United States)

The properties of the mixing layer in dynamic systems were studied by the example of a mathematical model of the cubic image type. Its role in the generation of information and the evolution of its significance was shown. At the moment of generation, information is of zero significance, and this significance then increases. A criterion of efficiency was proposed, and the optimum moment of making a decision in creative work was determined. It was shown that the increase in the variability of the parameters of a living system upon entry into the mixing layer and its decrease upon exit can serve as objective indicators of the transition of the system from one dynamic regime (attractor) to another. PMID:12723364

International Nuclear Information System (INIS)

An annealing with the nanosecond laser light pulse is applied for crystal lattice reconstruction of a disturbed near-surface layer, which was created in semiconductor material as a result of the implantation process. Radiation with energy density higher than the threshold value causes the melting of the surface layer and than the epitaxial recrystallization from the melt on a different substrate. Structural changes occurring in the Ge implanted Si crystals after annealing with different energy densities are investigated by means of the cross-section high-resolution transmission electron microscopy. (author)

Energy Technology Data Exchange (ETDEWEB)

A synthesis of papers based on the United Nations Environment Programme meeting on the ozone layer, Washington DC, this book contains valuable information on ongoing and planned activities concerned with stratospheric ozone problems, and presents the recommendations for further action resulting from the meeting. Possible changes in the characteristics of the ozone layer are discussed, together with the environmental, ecological, climatic, economic, and health implications of stratospheric ozone depletion. A comprehensive survey of current research in five European countries, the USA, Canada, and Australia is included and the volume is concluded by the UNEP report of the meeting and a world plan of action.

CERN Document Server

The conceptual design of the support structures of the EM muon chambers is presented. On each side of the detector the EM chambers are arranged in four layers: one layer of MDTs and the three layers of TGCs. The chambers are mounted on four individual wheel structures per side. The four wheels are inclined by 1.23% and suspended from two longitudinal beams parallel to the beam axis. In order to allow for the opening of the ATLAS detector the wheels can be displaced longitudinally over a distance of 6 m. In addition individual wheels can be separated from each other by up to 1 m for maintenance purposes.

British Library Electronic Table of Contents (United Kingdom)

The acoustic hyperlens can be realized by an alternating layered structure of water and fluid with negative mass density. Based on this alternating layered principle, we propose that an acoustic metamaterial consisting of three layers in water background can be designed to replace the fluid with negative mass density. The effective mass density and bulk modulus of the system which is composed of acoustic metamaterial and water are functions of the frequency. The effective mass density of such a system is close to the negative mass density of the fluid at a specific frequency; thus an acoustic metamaterial hyperlens can be achieved.

Science.gov (United States)

Orchestration Layer. Service Delivery . Datacenter. Infrastructure. Systems call API. E2E automated. Automate service-levels. Analyze & ...

Energy Technology Data Exchange (ETDEWEB)

Ultraviolet photoelectron spectra were measured for vanadyl phthalocyanine (VOPc) ultrathin films prepared on graphite to study effects of the molecular orientation and the electric dipole layer on the organic electronic states. VOPc has a permanent electric dipole perpendicular to the molecular plane, hence a well-defined electric dipole layer could be intentionally prepared by using the oriented monolayer. The observed binding-energy difference of the highest occupied molecular orbital (HOMO) bands between the oriented monolayer and the double layer was found to agree with the vacuum level shift, leading to a conclusion that the molecular energy level with respect to the substrate Fermi level is changed when the molecule is in the electric dipole layer.

International Nuclear Information System (INIS)

Short communication. 2 figs.

British Library Electronic Table of Contents (United Kingdom)

This work aims to contribute to the understanding of the influence of the ionospheric layer height (ILH) on the thin layer ionospheric model (TLIM) used to retrieve ionospheric information from the GNSS observations. Particular attention is paid to the errors caused on the estimation of the vertical total electron content (vTEC) and the GNSS satellites and receivers inter-frequency biases (IFB), by the use of an inappropriate ILH. The work relies upon numerical simulations performed with an empirical model of the Earth?s ionosphere: the model is used to create realistic but controlled ionospheric scenarios and the errors are evaluated after recovering those scenarios with the TLIM. The error assessment is performed in the Central and the northern part of the South American continents, a re...

International Nuclear Information System (INIS)

In this article, the ability of artificial neural networks in prediction of separation in steady two dimensional boundary layer flows is studied. Data for network training is extracted from numerical solution of an ODE obtained from Von Karman integral equation with approximate one parameter Pohlhousen velocity profile. As an appropriate neural network, a two layer radial basis generalized regression artificial neural network is used. The results shows good agreements between the overall behavior of the flow fields predicted by the artificial neural network and the actual flow fields for some cases. The method easily can be extended to unsteady separation and turbulent as well as compressible boundary layer flows. (author)

Energy Technology Data Exchange (ETDEWEB)

Membranes in Palladium and its alloys, in particular Pd/Ag alloys, are selectively permeable to hydrogen and can therefore be used to purify hydrogen. It is intended to use them as material for electrodes in fuel cells. As the manufacturing process of a substrate Pd/Ag-layer consists of several stages and is still not completely understood, it would be advantageous to be able to characterise separately the layers of noble metals obtained by electro-plating . Attempts are being made in this work to vary the cristallographical structure of the deposited alloy by the choice of test parameters and by sintering when depositing the Pd/Ag. The layers produced are to be examined using an interference microscope and X-ray diffraction. Moreover, the diffusion behaviour of the hydrogen is to be examined with an electro-chemical pulse method specifically developed for this purpose. figs., tabs., 27 refs.

Science.gov (United States)

... The insu- lation between gate and nanowire is the high-k dielectric HfO2, deposited by atomic layer depo- sition (ALD). ...

Science.gov (United States)

Map layer displays land designated as Suitable Land For Timber Production for the Forest Plan. It consists of all National Forest Lands less Non-forested ... ...

Energy Technology Data Exchange (ETDEWEB)

The growth of thin Pd[sub 2]Si films on Si(111) surfaces is studied using [ital in] [ital situ] transmission electron microscope under ultrahigh vacuum conditions. No immediate reaction of deposited Pd with Si is observed at room temperature. At [similar to]200 [degree]C, uniform Pd[sub 2]Si films can be formed. The thin Pd[sub 2]Si films are found to grow into strained islands at elevated temperatures. Interfacial misfit dislocations associated with interfacial steps propagate across the strained islands, causing the islands to grow layer-by-layer at the interface. The strain fields associated with the misfit dislocations are believed to be responsible for this behavior.

Energy Technology Data Exchange (ETDEWEB)

This paper reports the results of leaching experiments conducted with and without Thiobacillus ferroxidans at the same conditions in solution. The extent of leaching of ZnS with Bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, which no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T.ferroxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier ...

Energy Technology Data Exchange (ETDEWEB)

We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy){sub 3}{sup 2+} and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy){sub 3}{sup 2+}-doped silica nanoparticles and Au nanoparticles. UV-vis absorption spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry and ECL were used to characterize the uniform growth of the multilayer film. Since Ru(bpy){sub 3}{sup 2+} could still maintain its ECL property when doped into the silica nanoparticles, the as-prepared multilayer film could be used as an effective ECL sensor, and the sensor showed high sensitivity and good stability.

British Library Electronic Table of Contents (United Kingdom)

We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy)32+ and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy)32+-doped silica nanoparticles and Au nanoparticles. UV-vis absorption spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry and ECL were used to characterize the uniform growth of the multilayer film. Since Ru(bpy)32+ could still maintain its ECL property when doped into the silica nanoparticles, the as-prepared multilayer film could be used as an effective ECL sensor, and the sensor showed high sensitivity and good stability.

Science.gov (United States)

... AGARD AR-319, Volume 2. Knight, D., Zhou ... a Turbulent Boundary Layer in a Supersonic Flow. ... of Development of Separated Flows in Compression ...

British Library Electronic Table of Contents (United Kingdom)

The interlayer exchange coupling between Co/Pt perpendicular-to-plane magnetized layers across a thin IrMn spacer layer was experimentally studied. In contrast to earlier studies on interlayer coupling through antiferromagnetic NiO, which revealed an oscillatory coupling behavior as a function of NiO thickness, a ferromagnetic coupling was observed here in the range of IrMn thickness between 0.6 and 1.5nm and antiferromagnetic between 1.5 and 2.5nm. The antiferromagnetic coupling is attributed to an orange peel magnetostatic mechanism whereas the ferromagnetic coupling is attributed to an out-of-plane polarization of the antiferromagnetic IrMn layer induced by the interfacial exchange interaction with the adjacent out-of-plane ferromagnetic layers. Measurements of hysteresis loops versus t...

Science.gov (United States)

The portion of the Waterpocket Fold illustrated in this image includes layered rocks formed during the Mesozoic Era (~ 250 65 million years ago) the oldest ...

Energy Technology Data Exchange (ETDEWEB)

In order to obtain highly reliable InGaP/InGaAlP inner stripe (IS) lasers, the authors have clarified the relation between the maximum CW operation temperature and other laser characteristics, such as the pulsed threshold current, characteristic temperature, series resistance, and thermal resistance. The Al composition of the cladding layer, the carrier concentration of the p-cladding layer, and the thicknesses of the active layer and cladding layer have been optimized. It was found that an Al composition of 0.7 was the most suitable for the cladding layer, and the optimized carrier concentration was 4 x 10/sup 17/ cm/sup -3/. A maximum temperature of 90/sup 0/C was obtained for a 0.1 /mu/m active layer thickness and a 0.6 /mu/m cladding layer thickness. This is the highest value for InGaP/InGaAlP IS lasers, to our knowledge. In the case of ...

Energy Technology Data Exchange (ETDEWEB)

An inspection system was developed for spent fuel assemblies of PWR so that to check their general state, perform dimensional control and measure oxide layer thickness of peripheral rods. (orig./HP)

CERN Document Server

Many secure communication libraries used by distributed systems, such as SSL, TLS, and Kerberos, fail to make a clear distinction between the authentication, session, and communication layers. In this paper we introduce CEDAR, the secure communication library used by the Condor High Throughput Computing software, and present the advantages to a distributed computing system resulting from CEDAR's separation of these layers. Regardless of the authentication method used, CEDAR establishes a secure session key, which has the flexibility to be used for multiple capabilities. We demonstrate how a layered approach to security sessions can avoid round-trips and latency inherent in network authentication. The creation of a distinct session management layer allows for optimizations to improve scalability by way of delegating sessions to other components in the system. This session delegation creates a chain of ...

International Nuclear Information System (INIS)

... Industry, Material Science Research Laboratory, Yokosuka, Kanagawa (Japan)

Science.gov (United States)

This layer represents the different food storage facilities available at backcountry campsites along the coast of Kenai Fjords National Park. Site locations ... ...

Energy Technology Data Exchange (ETDEWEB)

Solar cells consisting of polymer layers sandwiched between a transparent electrode on glass and a metal top electrode are studied using dynamic time-of-flight secondary ion mass spectrometry (TOF-SIMS) in dual-beam mode. Because depth profiling of polymers and polymer-metal stacks is a relatively new field the craters were thoroughly investigated by environmental SEM (ESEM), interferometry, surface profilometry and tapping mode AFM. A huge increase in crater bottom roughness was observed when starting from the aluminum top layer going in depth, resulting in a loss of depth resolution. It is shown that layer-to-layer diffusion and contaminants at buried interfaces can be extracted from the depth profiles when taking into account the loss of depth resolution.

International Nuclear Information System (INIS)

Channeling effect measurements have been employed to investigate radiation damage produced by 100-keV Ar ions in preferred oriented polycrystalline metal-silicide layers, such as Pd_2Si and NiSi_2 layers formed on single-crystalline Si. For room-temperature implantation, an amount of the damage in Pd_2Si layers was found to saturate at doses between 3 x 10"1"4 and 1 x 10"1"7 ions/cm"2, where the minimum aligned yield of 1.5-MeV He ions was nearly 40% of the random one. On the contrary, it was observed that the NiSi_2 layers became amorphous at doses higher than 3 x 10"1"5 ions/cm"2. These results were confirmed by the reflection electron diffraction analyses.

International Nuclear Information System (INIS)

This study demonstrates amplified spontaneous emission (ASE) of the ultraviolet (UV) electroluminescence (EL) from ZnO at #lambda##approx#380 nm in the n-ZnO/ZnO nanodots-SiO_2 composite/p- Al_0_._1_2Ga_0_._8_8N heterojunction light-emitting diode. A SiO_2 layer embedded with ZnO nanodots was prepared on the p-type Al_0_._1_2Ga_0_._8_8N using spin-on coating of SiO_2 nanoparticles followed by atomic layer deposition (ALD) of ZnO. An n-type Al-doped ZnO layer was deposited upon the ZnO nanodots-SiO_2 composite layer also by the ALD technique. High-resolution transmission electron microscopy (HRTEM) reveals that the ZnO nanodots embedded in the SiO_2 matrix have diameters of 3-8 nm and the wurtzite crystal structure, which allows the transport of carriers through the thick ZnO nanodots-SiO_2 composite layer. The high quality of the n-ZnO layer was manifested by ...

Science.gov (United States)

Palladium silicides (Pd(x)Si) formed at a broadened interface after annealing, but a significant layer of alloy film is still free of silicon and carbon. ...

Energy Technology Data Exchange (ETDEWEB)

Passive films were formed on chromium by polarization at +400 mV/SHE in 0.5 M H{sub 2}SO{sub 4} for different times (30 minutes, 2 hours and 20 hours) without and with chlorides. The effect of chlorides was studied by adding NaCl to the solution before or after passivation. The chloride concentrations were 0.05, 0.3 and 1 M. The (i-E) curves recorded for Cr without and with Cl{sup -} are similar and the addition of chlorides after passivation has no significant effect on the current recorded in the passive state. The passive films were analyzed by angle-resolved XPS (AR-XPS). The measurements performed at different take-off angles of the photoelectrons show that the films have a bilayer structure constituted of an outer hydroxide layer, Cr(OH){sub 3}, and an inner oxide layer, Cr{sub 2}O{sub 3}. The thicknesses of the oxide and hydroxide layers are 3 A and 9 A, 6 A and 7 A and 6 A and 6 A for the films formed in 0.5 M H{sub ...

Energy Technology Data Exchange (ETDEWEB)

A computational model has been developed to calculate the potential and current distributions in the electrolyte phase and on the electrode surface for a system in which a part of the anode is passivated while the rest remains in the active dissolution state. The computation employs the finite element method allied with a boundary variation and a trial and error technique. From the obtained distributions, the location of the boundary between the active and passive regions on the anode can be predicted. In the case of a crevice, this means that a critical distance into the crevice exists beyond which active corrosion (crevice corrosion) takes place. In addition to the active/passive behavior of the material, solution conductivity, applied potential at the sample's outer surface, crevice gap and depth dimensions, and passive current density influence this critical distance to different degrees. The developed software package may also be used for (i) IR-induced crevice corrosion ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports that the point defect model for steady-state passive films formed anodically on metal s in aqueous environments has been extended to include irreversible dissolution of the film and the irreversible generation and annihilation of cation and oxygen vacancies at the metal/film and film/solution interfaces. THe model yields a number of diagnostic criteria that can be used to identify the majority (vacancy) charge carrier and to characterize the kinetic nature of the interfacial vacancy generation and annihilation processes. We use these criteria to show that the steady-state passive film that forms on nickel in acidic phosphate buffer solutions is a cation conductor and that cation transport from the metal to the solution involves irreversible ejection of cations from the film. On the other hand, the passive film that forms on tungsten in the same environment under steady-state conditions is found to be an oxygen ion conductor with the passive ...

International Nuclear Information System (INIS)

Interest in renewable energy systems that employ regenerative components to enable intermittent energy sources to service time varying loads is growing. The overall performance of these systems is intimately linked to the choice of the energy storage media and the efficiency of the energy conversion devices. Recent advances in electrolyser and fuel cell technologies may make small-scale hydrogen buffered renewable energy systems a practical reality in the near term. A research team at the University of Victoria - Institute for Integrated Energy Systems (IESVic) is developing a flexible distributed, laboratory-scale energy system called IRENE (Integrated Renewable Energy Experiment). The initial goal of this research is to explore the potential for constructing a regenerative energy system using early commercial and precommercial hydrogen storage and fuel cell energy conversion devices. Once implemented, research efforts will focus on the dynamic interactions ...

Energy Technology Data Exchange (ETDEWEB)

The PICTURE utility generates user defined pictures with black-and-white or color output, suitable for viewgraphs, slides, report diagrams - in general, any application requiring visual aids. The interactive menu-driven system allows a user to create a picture consisting of text, straight lines, graphs, and assortment of markers, splines and drawings, all in a variety of colors. Commands for manipulating the picture include moving, scaling, rotating, deleting, copying and changing the color of objects. Text strings may be aligned left, right, or centered, and have a vertical or horizontal path. Markers, circles and the large bold font may be filled or unfilled. The user may add or delete one of two overlay grids for help in positioning items. The final product may be saved in a text file for later retrieval. PICTURE currently runs on a VAX 11/780 with the DI-3000 commercial graphics package. Supported graphics devices include Ramtek 9400 and Metheus 440 frame ...

Energy Technology Data Exchange (ETDEWEB)

In developing new Tc-99m brain perfusion imaging agents for SPECT, a series of BAT (bis-aminoethanethiol) derivatives was prepared. These N/sub 2/S/sub 2/ ligands formed stable and neutral complexes with reduced Tc-99m, either by Sn(II)-PPi or sodium borohydride reduction. The purity of the Tc-99m complexes was >95% (HPLC reverse-phase column, acetonitrile: pH 7.0 buffer, 85:15). The biodistribution in rats was evaluated using I-125 iodoantipyrine (IAP), a free diffusible tracer, as the internal reference. Compounds with a free hydroxyl group (I and IV) showed lower brain uptake, inspite of high P.C.; this may be related to in vivo instability of the complexes. High initial brain uptake was observed for three compounds (II, III and V), however, only compound V (P.C.=384) showed significant brain retention. Planar imaging with compound V in a monkey demonstrated that the compound localized in brain and the retention time was T/sub 1/2/=35 min. Compounds of this ...

Energy Technology Data Exchange (ETDEWEB)

Lyophilized human whole blood control material containing lead was prepared for internal and external quality assurance to evaluate and improve the analytical performance of lead. The samples were prepared in four different concentrations from outdated human whole blood stabilized with glucose and a citrate/phosphate buffer and provided under clean room conditions to avoid contamination. The lyophilized samples are easy to reconstitute with water. The materials were evaluated according to a statistical model. The lead concentrations in the specimens are close to blood lead levels usually following environmental and industrial exposure, particular in occupational health to the control of lead exposure at work regulations. The materials are available to the commercial as well as the scientific community. The Danish External Quality Assessment Scheme (DEQAS) for lead in blood is intended to complement the internal quality control for the Danish laboratories assaying ...

Energy Technology Data Exchange (ETDEWEB)

Isotope shift measurements have been performed for the {sup 242{ital f}}Am fission isomer with target production rates of only a few per second. The method is based on resonance ionization spectroscopy (RIS) in a buffer gas cell with radioactive decay detection of the ionization process (RADRIS). A relative isotope shift ratio X{sub {ital exp}}=IS{sup 242{ital f},241}/IS{sup 243,241}=41.7{plus_minus}0.9 has been measured for the 500.02 nm transition corresponding to a nuclear parameter A{sup 242{ital f},241}=(5.4{plus_minus}0.3) fm{sup 2}. A preliminary analysis of the quadrupole moment based on the deformed Fermi model of the nuclear charge distribution results in Q{sub 20}=35.9{plus_minus}1.1({sup +0.3}{sub {minus}0.7}) {sub model} eb. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

International Nuclear Information System (INIS)

A nuclear fuel waste disposal vault would not likely be a sterile environment. Bacterial activity would be expected in those areas of the vault conducive to bacterial life, i.e., where effects of heat, moisture content, radiation and compaction would not prevent or severely restrict bacterial life and where suitable and sufficient nutrients would be present. An inventory of bacterial nutrients that would be emplaced 'intentionally' with vault materials (fuel waste, waste containers, buffer and backfill materials) has been made previously. This report assesses bacterial nutrients that would be added 'inadvertently' to a vault in the form of residues of materials used to excavate and operate a vault. Measurements of blasting material residues in the various water supplies, excavated broken rock (muck) and in cores drilled in old and new tunnel walls were made at AECL's Underground Research Laboratory. Results show that the largest potential nutrient addition (both ...

Energy Technology Data Exchange (ETDEWEB)

A new spectrofluorimetric method was developed for the determination of trace amount of nicotinamide adenine dinucleotide phosphate (NADP). Using europium (Eu{sup 3+})-tetracycline (TC) complex as a fluorescent probe, in the buffer solution of pH 7.60. NADP can remarkably enhance the fluorescence intensity of the Eu{sup 3+}-TC complex at {lambda} = 612 nm and the enhanced fluorescence intensity of Eu{sup 3+} ion is in proportion to the concentration of NADP. Optimum conditions for the determination of NADP were also investigated. The dynamic range for the determination of NADP is 4.4 x 10{sup -7} to 2.2 x 10{sup -6} mol l{sup -1} with detection limit of 6.9 x 10{sup -8} mol l{sup -1}. This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of NADP in synthetic water samples and in serum samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Eu{sup ...

Energy Technology Data Exchange (ETDEWEB)

Porous SnO{sub 2} nanotubes were prepared via electrospinning followed by calcination in air. As anode materials for lithium ion batteries, the porous nanotubes delivered a high discharge capacity of 807 mAh g{sup -1} after 50 cycles. Even after cycled at high rates, the electrode still retained a high fraction of its theoretical capacity. Such excellent performances of porous SnO{sub 2} nanotubes could be attributed to the porous and hollow structure which facilitated liquid electrolyte diffusion into the bulk materials and buffered large volume changes during lithium ions insertion/extraction. Furthermore, the nanoparticles of nanotubes provided the shorter diffusion length for lithium ions insertion which benefited in retaining the structural stability and good rate performance. Our results demonstrated that this simple method could be extended for the synthesis of porous metal oxide nanotubes with high performances in the applications of lithium ion batteries ...

Energy Technology Data Exchange (ETDEWEB)

The comprehension of passivity and its protective character against corrosion is closely connected with the electronic properties of passive films. Passive films formed anodically on carbon steel in borate/boric acid solution, pH 9.2, have been characterised by electrochemical impedance spectroscopy (EIS). Mott-Schottky plots and impedance measurements were made on films formed at different potentials and times. The investigation allowed the determination of the semiconductive properties of the films. The results of the capacitance response indicate that the passive films behave like highly doped n-type semiconductors, showing that the passive film properties are dominated by iron. The value of donors density (N {sub D}) for the passive film is of the order of 10{sup 21} cm{sup -3} and decreases with increasing formation time and potential, indicating that defects decrease with increasing film thickness. Based on the information about the physical phenomena, an equivalent circuit is ...

British Library Electronic Table of Contents (United Kingdom)

An extremely sensitive stripping voltammetric procedure for ultra-trace determination of iridium(III) is reported. The method is based on the interfacial accumulation of the iridium(III)-CTAB complex onto the glassy carbon electrode, followed by the catalytic reduction of the adsorbed complex in the presence of bromate. 0.3molL^-^1 acetate buffer pH 4.7+6.9x10^-^2molL^-^1 NaBrO3+2.7x10^-^5molL^-^1 cetyltrimethylammonium bromide (CTAB)+0.2molL^-^1 KCl was employed as the supporting electrolyte. The analytical procedure was verified by the analysis of the standard reference materials: Sea Water BCR-CRM 403 and Fresh Water NIST-SRM 1643d. The accuracy, expressed as relative error e%, was satisfactory, being lower than 6%, while precision as repeatability, expressed as relative standard deviat...

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In order to understand the anodic behaviour of Al--Mo and Al--W amorphous alloys in the borate buffer electrolyte, samples of these alloys were polarized galvanostatically. The resultant anodic films were thicker than the passive films formed during potentiodynamic polarization enabling detailed examination of the films and alloy substrates by surface analytical methods. AES investigations suggest that the anodic films formed at low and moderate voltages on Al--Mo or Al--W amorphous alloys consist of Al-oxide, whereas refractory metals remain unoxidized and enriched at the film/substrate interface. Molybdenum and tungsten act as 'dissolution moderators', restraining the substrate dissolution process at the film/substrate interface. However, after anodization at high voltages (50 V), AES revealed the presence of an oxidized refractory metal in the inner part of the anodic film. Based on these results of growth of thick anodic films, the role of Mo ...

International Nuclear Information System (INIS)

High-resolution proton nuclear magnetic resonance spectroscopy has been used to investigate the molecular mechanism of the Bohr effect of human normal adult hemoglobin in the presence of two allosteric effectors, i.e., chloride and inorganic phosphate ions. The individual hydrogen ion equilibria of 22-26 histidyl residues of hemoglobin have been measured in anion-free 0.1 M HEPES buffer and in the presence of 0.18 M chloride or 0.1 M inorganic phosphate ions in both deoxy and carbonmonoxy forms. The results indicate that the #beta#2-histidyl residues are strong binding sites for chloride and inorganic phosphate ions in hemoglobin. The affinity of the #beta#2-histidyl residues for these anions is larger in the deoxy than in the carbonmonoxy form. Nevertheless, the contribution of these histidyl residues to the anion Bohr effect is small due to their low pK value in deoxyhemoglobin in anion-free solvents. The interactions of chloride and inorganic phosphate ions with ...

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Interest in finding out passive ways to keep the variation in the indoor climate within the comfort zone is gaining in popularity. One possible solution is the use of the moisture-buffering property of materials. In this study, the effects of the ventilation system and moisture-buffering properties of the building fabric on the stability of the indoor temperature and humidity are analysed by means of long-term field measurements. Indoor climate measurements were carried out in 170 detached houses (248 rooms). Temperature and relative humidity were measured continuously in bedrooms and living rooms at one-hour intervals over a one-year period. In general, it may be concluded that in this study, the ventilation had a greater effect on the indoor climate than the properties of the building fabric. The dampening effect of hygroscopic materials was remarkably less in the field measurements than it was in simulations in different studies. This ...

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Regularly considered as the 'success story' of the world environmental policy, the regulation relative to ozone destructive products should allow a recovery of the ozone layer around the middle of the 21. century. This article analyzes how, two decades after the signature of the Montreal protocol, such forecasts are still valid and how new parameters, like the increase of the greenhouse effect, will influence this recovery. (J.S.)

International Nuclear Information System (INIS)

The effects of CH_4 content at nitriding step in the low temperature two-step plasma treatment (carburizing+nitriding) on the surface characteristics of AISI304L stainless steel were investigated. The low temperature plasma carburizing was carried out at 550 .deg. C for 5h in a gas mixture of H_2 Ar and CH_4. The thickness of a carburized layer increased up to about 30 #mu#m and corrosion resistance of the layer decreased due to the precipitation formed at the grain boundary. After carburizing, a low temperature plasma nitriding was subsequently performed in the same chamber at 400 .deg. C for 15h to improve corrosion resistance and to further increase the surface hardness. The surface hardness of a N-enriched layer after nitriding reached up to 1,200HV_0_._1, which is much higher than that of as-carburized layer(750 HV_0_._1). The post nitriding process had a beneficial effect on reducing the ...

International Nuclear Information System (INIS)

Epitaxial cobalt disilicide (CoSi_2) layers are grown on n-Si_0_._8_3Ge_0_._1_7/n-Si(001) using a sacrificial Si capping layer at the growth temperature T_s=650 deg. C by reactive chemical vapor deposition using cyclopentadienyl dicarbonyl cobalt (Co(#eta#"5-C_5H_5)(CO)_2). Structural and electrical properties of epi-CoSi_2/Si_0_._8_3Ge_0_._1_7/Si(001) were measured by transmission electron microscopy, X-ray diffraction, Auger electron spectroscopy and sheet resistance measurement as a function of annealing temperature. The combined results showed that the epitaxial CoSi_2 phase by the reaction of Co with the Si capping layer was formed in the as-grown layers. Rapid thermal anneals for the investigation of thermal stability of the as-grown layers showed good thermal stability of the epitaxial CoSi_2 layers with the low sheet resistance value as low as congruent ...

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The average angle of repose and the packing density of random planar heaps of hard disks falling ballistically onto a sticky base line, where the first layer of disks is quenched in random positions, are computed for heaps with a small fixed number of gaps in the base layer. The results we find appear to be almost independent of the size of the heap and they agree with those obtained from computer simulations of large systems.

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Clays and zeolites are among the most important of natural dusts by virtue of their occurrence through out the world on the earth`s surface and their important industrial uses. (The 1:1 layer silicates, including the serpentine and kaolin minerals, are not addressed in this chapter.) This chapter provides basic information on a variety of important aspects of each mineral, including crystal structure diagrams of each and references to more detailed discussions. 110 refs., 20 figs.

Science.gov (United States)

The synthesis of experimental data concerning the effect of jet stagnation conditions on the drag of various afterbodies is presented. Jet pressure ratio effect on boattail pressure and on boundary layer separation is analyzed. This study is made for several values of the boundary layer thickness, taking into account the fact that some test rigs make its control possible by means of tangential blowing.

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The paper reports on the results of a study of the synthesis conditions effects on magnetic and transport properties of nanosized layers of high-T{sub c} diluted magnetic semiconductors (DMS), such as Ge:Mn, Si:Mn and Si:Fe, fabricated by laser-plasma deposition over a wide range of the growth temperature, T{sub g}=(20-550) deg. C on single-crystal GaAs or Al{sub 2}O{sub 3} substrates. Ferromagnetism of the layers was detected by measurement data of the magneto-optical Kerr effect, anomalous Hall effect, negative magnetoresistance and ferromagnetic resonance (FMR) at 5-500 K. The optimum growth temperature, T{sub g}, for Si:Mn/GaAs layers with T{sub c}{approx}400 K is shown to be about 400 deg. C. The Si:Mn/Al{sub 2}O{sub 3} layers with 35% of Mn have the metal-type of conductivity with manifestation of magnetization up to room temperature. Different types of uniformly doped structures and digital ...

International Nuclear Information System (INIS)

Nitric acid leaching from the weak base anion (WBA) exchanger had been evaluated and based on this a 5% mixture of nitric acid loaded weak base anion exchanger with fresh weak base anion exchanger (NLWBA) at the bottom of the ion exchange column has been devised to maintain an outlet pH in the range of 5.0 to 5.5 during Gd removal from the moderator system of TAPP - 3 and 4. A three layered bed had been constituted wherein strong acid cation (SAC) exchanger is placed as the top layer while a mixed bed of SAC and WBA or pure WBA is used as the middle layer and the 5% NLWBA was used as the bottom most layer. This bed configuration would result in an iso-pH regime in the moderator system during the Gd removal along with quantitative removal of Gd. Two three-layer bed columns were prepared at TAPS - 3 and 4 in July 07. The resin was loaded in batches and after preparing the column, the ...

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The effective elastic constants of a superlattice composed of layers of orthorhombic symmetry (with principal axes along the superlattice axis) are derived. These results generalize previous determinations for elastically isotropic layers (Rytov, Akust. Zh. 2, 71 (1956) (Sov. Phys.: Acoust. 2, 68 (1956))), but a completely different approach is used.

Science.gov (United States)

A method is described to smear extremely thin layers of nuclear emulsion on labeled electron microscope preparations and to measure the thicknesses of these layers, Without further separation, preparation and emulsion can be observed after exposure and development in an electron microscope. The source of the tracks formed in the emulsion can be exactly identified and the size and structure determined. This method finds applications in dust research and also in the analysis of medical and biological sections. Further information can be obtained about properties of different emulsions. (auth)

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The sequential layer-by-layer adsorption of polyanions and polycations to build polyelectrolyte multilayers has triggered enormous interest in their potential uses in a wide range of fields, from photonic to pharmaceutical applications. We show that the conformation of the solvent swollen films - prior to drying - is determined by the initial adsorption conditions, but can be altered ex-situ by exposure to a liquid phase of very high ionic strength. Recently it has been observed that the swelling depends on the charge of the outermost layer. In the PAH/PSS system we saw that assemblies with PSS as the outermost layer swell more than those with PAH outside. A neutron reflectivity study of this effect in addition indicated the existence of two kinds of water, bound with different strength within the films. Beside an unexpected two-step kinetics of swelling, the reflectivity curves of the layers against ...

British Library Electronic Table of Contents (United Kingdom)

A laboratory-scale multi-layer system was developed for the adsorption of PCDD/Fs from gas streams at various operating conditions, including gas flow rate, operating temperature and water vapor content. Excellent PCDD/F removal efficiency (>99.99%) was achieved with the multi-layer design with bead-shaped activated carbons (BACs). The PCDD/F removal efficiency achieved with the first layer adsorption bed decreased as the gas flow rate was increased due to the decrease of the gas retention time. The PCDD/F concentrations measured at the outlet of the third layer adsorption bed were all lower than 0.1ng I-TEQNm-3. The PCDD/Fs desorbed from BAC were mainly lowly chlorinated congeners and the PCDD/F outlet concentrations increased as the operating temperature was increased. In addition, the r...

International Nuclear Information System (INIS)

We show that the morphology and the luminescence properties of ZnO layers produced by magnetron sputtering can be controlled by technological parameters of sputtering, particularly by the ratio of argon to oxygen gases in the gas flow during the growth process. Smooth and flat layers were produced with a high Ar/O ratio, while porous layers with various morphologies were obtained with a low Ar/O ratio. The layers produced with O/Ar ration equal to 10 exhibit extremely high near-bandgap luminescence intensity even higher in comparison with bulk ZnO single crystals. The free carrier density estimated from the analysis of photoluminescence spectra is also very high in these samples suggesting that these technological conditions promote both optical and electrical activation of the doping Al impurity. The samples grown with high Ar/O ratios exhibit strong visible emission which is controlled by the ...

International Nuclear Information System (INIS)

We report on the possibility to prepare ZnSe porous layers with different degrees of porosity by means of electrochemical methods. The prepared porous structures were characterized using scanning electron microscopy (SEM), photoluminescence (PL) and cathodoluminescence (CL) techniques. The PL of the as-grown material and porous layers measured at low temperatures (10 K) was found to be dominated by an emission band at 2.796 eV as well as a band at 2.700 eV with several phonon replicas. The analysis of the dependence of these bands upon the excitation power density and temperature suggests that free-to-bound and respectively donor-acceptor electron transitions are responsible for the emission bands involved. The comparison of SEM and CL images taken from the same porous regions demonstrated that cathodoluminescence intensity from layers with small characteristic sizes of the porous entities (around 50 nm) is weaker than that ...

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

International Nuclear Information System (INIS)

Hydrolysis kinetics of the lead silicate glass (LSG) with 40 mol% PbO in 0.5 N HNO_3 aqueous acid solution was investigated. The surface morphology and the gel layer thickness were studied by scanning electron microscopy (SEM) micrographs. Energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma spectroscopy (ICP) were used to determine the composition of the gel layer and the aqueous solution, respectively. The silicon content of the dissolution products was determined by using weight-loss data and compositions of the gel layer and the solution. The kinetic parameters were determined using the shrinking-core-model (SCM) for rate controlling step. The activation energy obtained for hydrolysis reaction was Q_c_h_e = 56.07 kJ/mole. The diffusion coefficient of the Pb ions from the gel layer was determined by using its concentration in solution and in LSG. The shrinkage of the sample and ...

Science.gov (United States)

The aim of the present study focuses on experimentally demonstrating the efficacy of using angularly-variable fiber geometry to achieve the desired tissue-layer selection and probing depths with the further objective of enhancing the sensitivity and specificity of spectral diagnosis in stratified architectures that resemble human cervical epithelia. The morphological and biochemical features of epithelial tissue vary in accordance with tissue depths; consequently, the accuracy of spectroscopic diagnosis of epithelial dysplasia may be enhanced by probing the optical properties of this tissue. When correlated to cellular dysplasia, layer-specific changes in tissue optical properties may be deciphered by reflectance spectroscopy coupled with angularly-variable fiber geometry. This study addresses the utility of using such angularly-variable fiber geometry for resolving spatially-specific spectral signatures of tissue pathology. This is ...

International Nuclear Information System (INIS)

The Compton backscatter technique has been applied to lap-joint in aircraft structure in order to determine mass loss due to exfoliative corrosion of the aluminum alloy sheet skin. The mass loss of each layer has been estimated from Compton backscatter A-scan including the aluminum sheet, the corrosion layer, and the sealant. A Compton backscattering imaging system has been also developed to obtain a cross-sectional profile of corroded lap-splices of aging aircraft using a specially designed slit-type camera. The camera is to focus on a small scattering volume inside the material from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the layered structure is scanned by moving the scattering volume through the thickness direction of the specimen. The theoretical model of the Compton scattering based on Boltzmann transport ...

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We have investigated the diffusion enhancement mechanism of boron-enhanced diffusion (BED), wherein boron diffusivity is enhanced four to five times over the equilibrium diffusivity at 1050&hthinsp;{degree}C in the proximity of a silicon layer containing a high boron concentration. It is demonstrated that BED is driven by excess interstitials injected from the high boron concentration layer during annealing. For evaporated layers, BED is observed above a threshold boron concentration between 1{percent} and 10{percent}, though it appears to be closer to 1{percent} for B-implanted layers. For sub-keV B implants above the threshold, BED dominates over the contribution from transient-enhanced diffusion to junction depth. For 0.5 keV B, this threshold implantation dose lies between 3{times}10{sup 14} and 1{times}10{sup 15} cm{sup {minus}2}. It is proposed that the excess interstitials responsible for BED ...

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A new package for the air transport of hazardous materials is currently being developed in the Transportation Systems Department at Sandia National Laboratories. The baseline design has a unique impact limiter which uses layers of aluminum screen wire and aramid cloth fabric. A primary motivation for selecting this unusual combination of materials is the need for the impact limiter to not only limit the amount of load transmitted to the primary container but also remain in place during impact events so that it provides a thermal barrier during a subsequent fire. A series of uniaxial and confined compression tests indicated that the layered material does not behave like other well characterized materials. No existing constitutive models were able to satisfactorily capture the behavior of the layered material; thus, a new plasticity model was developed. The new material model was then used to characterize the response of air ...

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The objective of the current study was the gradual development of the formation of the nitride layer during inductive r.f. plasma nitriding. The study centers on characterization of refined layers and plasma diagnostics in the vicinity of the sample, and raises critical questions of how the layers and interfacial microstructure might affect the near-surface properties. The composition of the plasma near the surface of the sample (plasma layer) was examined by optical emission spectroscopy and mass spectrometry during plasma nitriding and while sputtering the sample after the nitriding process. It was observed that during the nitriding process, the plasma layer contains Ti, NH[sub n] species, N (or/and N[sup +]), H[sub n] species (or/and H[sup +][sub 2]). However, when the nitrided sample was exposed to argon plasma, Ti, Al and NH were observed. It was found that two distinct ...

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Wear-resistant TiN coatings deposited on tool steels are used frequently in industry. There is a trend towards further optimizing these coatings, e.g. by plasma nitriding the tool surface prior to TiN deposition. In this work the influence of the nitriding conditions on the surface properties of AISI 304 and ASP 23 tool steels was investigated. The plasma nitriding was carried out in a triode ion plating configuration normally used to deposit TiN coatings. At the surface of AISI 304 stainless steel, only a thin compound layer (Fe{sub 4}N, Fe{sub 3}N) was found, probably as a consequence of the rather slow nitrogen diffusion in the austenite matrix. For ASP 23 high speed steel, the different nitriding behaviour of the martensitic matrix causes the formation of a diffusion layer which results in an increase in hardness at the surface. On an analogous set of specimens the TiN deposition was started immediately after the plasma nitriding. To ...

International Nuclear Information System (INIS)

Alloy 690 and Alloy600 are used as a material for the steam generator tubing in the pressurized water reactor(PWR) of nuclear power plants due to its high corrosion resistance. Although those are a highly corrosion resistance material, their stress corrosion cracking(SCC) have been found on occasion, which are deeply related to a surface oxide film on a base material which have occurred on the primary side as well as the secondary side of a tubing. And The SCC is accelerated in the existing Pb which is the impurity of secondary steam generator components. The Oxide on a steel surface in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. The outer layer of the oxide is less adhesive, which is formed by a dissolution and precipitation mechanism. Growth processes of the inner ...

International Nuclear Information System (INIS)

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

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In the context of the special research area 561 (Thermally highly loaded, open-porous and cooled multi-layer systems for combined-cycle power stations), the actual technical and scientific realizations are to be extended and new scientific bases are to be created in order to realize total efficiencies of 65 %. In addition, innovative material solutions and new concepts must be compiled for the cooling and drainage. Under this aspect, the author of the contribution under consideration reports on the development of open-porous multi-layer systems for steam turbines of the 700 C technology. It results an efficiency potential of 12 % and a potential of 15 % with the reduction of CO{sub 2} in relation to the actual state of the art. Thereby, the potential of future combined-cycle power stations is not yet exhausted.

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Fixation of /sup 14/CO/sub 2/ and activities of sucrose-synthesizing enzymes, sucrose phosphate synthetase (SPS) and sucrose synthase (SS), were assayed in tissues of developing fruit and source leaves from Citrus paradisi Macf. SPS activity of both the outer, chlorophyllous layer of the fruit (flavedo) and source leaves was 10-fold greater than that of the inner, largely non-chlorophyllous layer of the fruit peel (albedo). In contrast, SS activity of the flavedo was 2-fold greater than that of the albedo and 10-fold greater than that of leaves. Fixation of /sup 14/C-photosynthates in isolated tissues (flavedo 2x > albedo) and their redistribution in intact fruit indicated that flavedo functions as both source and sink. Activities of sucrose-synthesizing enzymes were consistent with this dual function.