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Nanoparticle metal oxides offer a wide variety of potential applications in medicine due to the unprecedented advances in nanobiotechnology research. In this work, the effect of zinc oxide (ZnO) nanoparticles prepared by mechano-chemical method on the antibacterial activity of different antibiotics was evaluated using disk diffusion method against Staphylococcus aureus and Escherichia coli. The average size of ZnO nanoparticles was between 20 nm and 45 nm. Although ZnO nanoparticles (500 mg/disk) decreased the antibacterial activity of amoxicillin, penicillin G, and nitrofurantoin in S. aureus, the antibacterial activity of ciprofloxacin increased in the presence of ZnO nanoparticles in both test strains. A total of 27% and 22% increase in inhibition zone areas was observed for ciprofloxac...

British Library Electronic Table of Contents (United Kingdom)

Abstract A series of polypropylene carbonate (PPC)/ZnO nanocomposite films with different ZnO contents were prepared via a solution blending method. The morphological structures, thermal properties, oxygen permeability, water sorption, and antibacterial properties of the films were investigated as a function of ZnO concentration. While all of the composite films with less than 5 wt % ZnO exhibited good dispersion of ZnO in the PPC matrix, FTIR and SEM results revealed that solution blending did not lead to a strong interaction between PPC and unmodified ZnO. As such, poor dispersion was induced in the composite films with a high ZnO content. By incorporating inorganic ZnO filler nanoparticles, the diffusion coefficient, water uptake in equilibrium, and oxygen permeability decreased as the ...

British Library Electronic Table of Contents (United Kingdom)

Polycrystalline ZnO doped with Mn (5 and 10at%) was prepared by the co-precipitation method. The effect of Mn doping on the photocatalytic, antibacterial activities and the influence of doping concentration on structural, optical properties of nanoparticles were studied. Structural and optical properties of the particles elucidated that the Mn2+ ions have substituted the Zn2+ ions without changing the Wurtzite structure of ZnO. The optical spectra showed a blue shift in the absorbance spectrum with increasing dopant concentration. The photocatalytic activities of ZnO powders were evaluated by measuring the degradation of methylene blue (MB) in water under the UV region. It was found that undoped ZnO bleaches MB much faster than manganese doped ZnO upon its exposure to the U...

British Library Electronic Table of Contents (United Kingdom)

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

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We report a simple method for the label-free detection of double-stranded DNA using surface-enhanced Raman scattering (SERS). We prepared cetyltrimethylammonium bromide (CTAB)-capped silver nanoparticles and a DNA-nanoparticle complex by adding silver nanoparticles to {lambda}-DNA solutions. In the present study, the utilization of CTAB-capped silver nanoparticles facilitates the electrostatic interaction between DNA molecules and silver nanoparticles; at the same time, the introduction of DNA avoids adding aggregating agent for the formation of nanoparticle aggregates to obtain large enhancement of DNA, because the DNA acts as both the probe molecules and aggregating agent of Ag nanoparticles. Atomic force microscopy (AFM) studies show that the morphology of DNA-Ag nanoparticle ...

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Composite ZnO/Ag nanoparticles have been formed via the photocatalytic reduction of silver nitrate over the ZnO nanocrystals, their optical, electrophysical and photochemical properties have been investigated. Mie theory has been applied to analyze the structure of the absorption spectra of ZnO/Ag nanocomposite. The irradiation effects upon the optical properties of ZnO/Ag nanostructure have been investigated. It has been found that the irradiation of ZnO/Ag nanoparticles results in electrons accumulation by both the semiconductor and the metallic components of the nanocomposite. It has been found that silver nitrate can be photochemically deposited onto the surface of ZnO nanoparticles under the illumination with the visible light in the presence of the sensitizer - methylene blue. Kinetics of the sensitized Ag(I) photoredution has been studied. It has been concluded that the key ...

British Library Electronic Table of Contents (United Kingdom)

Emeraldine base (EB) polymer?ZnO nanoparticles composite films has been synthesized by solution casting technique on ITO-coated glass substrate and characterized by XRD, FTIR and TEM for their structure and morphology. Dielectric behaviour of these composite films has been investigated in the very low frequency region to medium frequency region (1?kHz?1?MHz). The dielectric constant of the composite with 30% nanoparticles is almost one-tenth of the pure EB. The dielectric value becomes constant in the frequency region greater than 400?kHz. The change in dielectric behaviour of the composite is explained on the basis of multilayered interface formed between the ZnO nanoparticles and emeraldine chains. Nanoparticles have high energy surface which is responsible for the decrease of free volum...

British Library Electronic Table of Contents (United Kingdom)

In this paper, multilayer oxide nanorods were deposited in the nanopores of anodic aluminum oxide (AAO) via solution infiltration followed by heat treatment. The nanorods have a core-shell structure. First, the shell (nanotube) with the thickness of about 40nm was made of TiO"2 through the hydrolysis of (NH"4)"2TiF"6. Second, silver nanoparticles with the diameter of about 3nm were added into the TiO"2 layer through thermal decomposition of AgNO"3 at elevated temperatures. Then, cylindrical cores (nanorods) of CoO and ZnO with 200nm diameter were prepared, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and composition of the nanorods. UV-vis light absorption measurements in the wavelength range from 350 to...

Science.gov (United States)

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

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A mesoscopically ordered lamellar gel phase of a polymer-grafted, lipid-based complex fluid is used as a scaffolding to spatially organize inorganic nanoparticles. The complex fluid provides both a highly anisotropic environment and a segregated aqueous and organic domains in which inorganic nanoparticles can be selectively placed by tailoring their size and surface characteristics. Three types of silver nanoparticles -- underivatized, surfactant-stabilized, and dodecanthiol-derivatized -- were evaluated. Comparison of the surface plasmon resonance of the various silver particles dispersed in conventional solvents to those contained within the complex fluid was used to determine the region of spatial localization in the lamellar gel phase. Silver particles rendered hydrophobic by capping with an alkane thiol insert into the hydrocarbon bilayer region. Surfactant-stabilized and underivatized silver ...

British Library Electronic Table of Contents (United Kingdom)

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer suffered the sol-gel reaction under alkaline conditions in the presence of titanium oxide nanoparticles in tetrahydrofuran to afford the corresponding fluorinated oligomer/titanium oxide nanocomposites[RF-(VM-SiO2)n-RF/TiO2] in excellent to moderate isolated yields. These fluorinated composites thus obtained were nanometer size-controlled fine particles, and exhibited good dispersibility and stability in traditional organic solvents except for water. These fluorinated nanocomposites were applied to the surface modification of glass to exhibit not only a completely superhydrophobic characteristic (a water contact angle: 180degree) with a non-wetting property against water droplets but also a good oleophobicity imparted by fluoroalkyl seg...

Science.gov (United States)

Nanosized particles are important because of their unique properties, different from the bulk, which leads to their enhanced catalytic, photocatalytic and electronic properties. This work has dealt with three different nanoparticle systems in the context of three different aspects of nanoparticle properties: (a) photocatalytis (TiO2/metal) system, (b) luminescence (CdSe) (c) alloying (Pt-Ag and Pd-Ag). The initial photocatalytic enhancement obtained by adding noble metal on semiconductor nanoparticles, degrades as fast as in 15 minutes and questions their long-term performance. XANES measurements on such irradiated systems like TiO2/Au, TiO2/Pt, TiO2/Ir indicates a positive oxidation state of these noble metals which renders them as recombination centers for photo-excited electrons and explains the decreased photocurrent. The oxidation is caused by holes. The EXAFS results also indicate a change of the interfacial structure ...

CERN Document Server

Textile machinery and accessories -- Bearings for bottom rollers and allied dimensions -- Caps with central nose and caps with side lugs

International Nuclear Information System (INIS)

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

British Library Electronic Table of Contents (United Kingdom)

Metallic Zn films were deposited on glass substrates by electron-beam evaporation. ZnO films were synthesized by thermal oxidation of Zn metallic films in air. At the annealing temperature of 550 ?C, ZnO nanowires appeared on the surface, which mainly result from the decrease of oxidation rate. A ZnO ultraviolet photodetector was fabricated based on a metal-semiconductor-metal planar structure. The detector showed a large UV photoresponse with an increase of two orders of magnitude. It is concluded that promising UV detectors can be obtained on ZnO films by thermal oxidation of Zn metallic films. The ways of performing spectral response measurements for polycrystalline ZnO films are also discussed.

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The pressure dependence of the photoluminescence (PL) transition associated with the fundamental band gap of ZnO nanowires has been studied at pressures up to 15 GPa. ZnO nanowires are found to have a higher structural phase transition pressure around 12 GPa as compared to 9.0 GPa for bulk ZnO. The pressure-induced energy shift of the near band-edge luminescence emission yields a linear pressure coefficient of 29.6 meV/GPa with a small sublinear term of -0.43 meV/GPa{sup 2}. An effective hydrostatic deformation potential -3.97 eV for the direct band gap of the ZnO nanowires is derived from the result.

British Library Electronic Table of Contents (United Kingdom)

The properties of ZnO films were investigated as functions of annealing temperatures in H2/Ar and vacuum. The resistivities and mobilities of ZnO films decreased with increase of annealing temperatures in vacuum and H2/Ar ambients. However, the carrier densities of ZnO films increased with increase of annealing temperatures in vacuum and H2/Ar ambients. The resistivities of ZnO2 films annealed at 300degreeC were 2186cm and 798cm in H2/Ar and vacuum ambients, respectively. The resistivities of ZnO films annealed in vacuum and H2/Ar ambients at 600degreeC were similar with 0.040cm and 0.035cm, respectively. The hydrogen donor was more dominant than the oxygen vacancy or Zn interstitial donor in ZnO films annealed in ambient H2/Ar at low temperatures. The average optical transmission was >82%...

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UK PubMed Central (United Kingdom)

Early simian virus 40-specific mRNA was isolated from lytically infected and stably transformed cells and analyzed with respect to the 5'-terminal cap content. An analogous diversity of capped structures...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Rare-earth oxides are doped into ZnO varistors as grain growth inhibitors for increasing the varistors' voltage gradients. However, their leakage currents become large and their nonlinear coefficients decrease at the same time. The reasonable explanation for such a phenomenon has not yet been available. In this paper, the temperature dependences of varistor samples' leakage currents are investigated, which reveal that the increased leakage currents of ZnO varistors with Y2O3 doping are mainly due to the bypass paths through the intergranular materials at grain corners.

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Nanoparticles represent versatile building blocks in material science and nanotechnology. Thereby, the defined assembly of nanostructures (13 and 56 nm in diameter, respectively) is of significant importance. Short DNA sequences can be bound to the nanoparticle surface thus enabling highly specific DNA hybridization-driven events that direct the formation of nanoparticle constructs.In this paper, examples for the defined formation of gold nanoparticle constructs are demonstrated. In addition, gold-silver core-shell nanoparticles are introduced as further building blocks for the hybridization-controlled formation of nanoparticle constructs.

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In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles.

Environmental Research Database

ObjectivesThe development of novel formulations of nanoparticles in the nanotechnology industry and their increasing importance and use in industry means there is certainty of human environmental exposures in both the workplace and the general environment. The pulmonary route of exposure to airborne nanoparticles is a major one, as nanoparticles are handled in industry, escape from workplaces and products containing nanoparticles undergo attrition in the environment. There is a substantial problem for ris [continued...]DescriptionNanoparticles are extremely small particles, each individual particlel being less than one ten millionth of a metre in size. We are exposed to nanoparticles in busy streets as they are present in traffic exhaust produced from combustion of fuel and such nanoparticles are considered to be important in causing the ...

Energy Technology Data Exchange (ETDEWEB)

Nanocrystalline ZnO films were fabricated via a simple method involving the oxidation of Zn films at a remarkably low temperature of 380 C. X-ray diffraction study confirmed that the Zn films were completely oxidized even at the low temperature of 380 C and the ZnO films fabricated were of polycrystalline wurtzite structure. Room temperature optical pumping using a frequency-quintupled Q-switched Nd:YAG laser ({lambda}=213 nm) exhibited that sharp peaks at around 3.12 eV emerged above excitation powers of {proportional_to}7 MW/cm{sup 2}, demonstrating lasing in the ZnO films. These results represent that the process is a simple, promising approach for fabricating ZnO of sufficient optical performance for use as ultraviolet (UV) light emitters and an alternative UV laser source; both are key components in short-wavelength photonic devices. (orig.)

International Nuclear Information System (INIS)

This paper presents a spatial gaming model with price caps for deregulated electricity markets. There has been heated debate on price caps that have been enforced in deregulated electricity markets. Opponents argue that price caps may send wrong economic signals while advocates argue that price caps are good for damping market power. This paper does not intend to take a stand in the argument. Given the fact that price caps are enforced in several deregulated regional electricity markets in the US, a logical step is to reflect this reality in gaining modeling. However, current gaining models have not included any price cap formulation. This paper is the first one to address the issue. DC power flow equations are used for representing the spatial nature of an electrical network. An algorithm is proposed to find a generalized Nash equilibrium under the enforcement ...

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The high-frequency data from 12 sensors at the ITCE 1976 are analyzed to determine the Kolmogoroff constants for velocity, temperature and humidity fluctuations, ..cap alpha../sub u/, ..cap alpha../sub T/, and ..cap alpha../sub q/. The occurrence of aliasing in the spectral analysis in some cases together with the limited response of some sensors at the higher frequencies introduces some uncertainties into the analysis. The Soviet sonic anemometer, fine-wire thermometer and infrared hygrometer and the Australian infrared hygrometer provide the best information, namely that: ..cap alpha../sub u/ = 0.59 +/- 0.01, ..cap alpha../sub T/ = 0.68 +/- 0.02, ..cap alpha../sub q/ = 0.76 +/- 0.03, where the errors quoted refer solely to statistical errors. The other instruments provide general support to these values. The technique of using spectral density measurements to ...

British Library Electronic Table of Contents (United Kingdom)

Properties of photoconductive ultraviolet detectors fabricated on ZnO films were presented. Highly c-axis oriented ZnO films were grown on glass substrates by pulsed laser deposition. Ultraviolet photodetectors were fabricated based on metal-semiconductor-metal planar structures. The photoresponsivity and the quantum efficiency are much higher in the ultraviolet range than in the visible range, and the peak values are around 360nm. Photocurrent transients show that the detector has a large photocurrent with the peak value of 2.8mA, and a slow photoresponse with a rise time of 5min and a decay time of 7min. The response curve of the detector is fitted well with exponential curve. The large photocurrent should result from the both effects of the accumulation of conduction electrons and the d...

J-STORE (Japan)

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DEFF Research Database (Denmark)

Udgivelsesdato: 2008/5

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W have introduced template-synthesized metal phosphate nanoparticle labels for electrochemical immunoassay. Such use of an apoferritin template offers a simple and convenient route to prepare metallic nanoparticle labels for electrochemical immunoassays and avoid the complicated and time-consuming nanoparticle synthesis process (QD synthesis). Releasing metal ions from metal phosphate in an acetate buffer (pH 4.6) eliminates the harsh condition in the traditional metallic nanoparticle dissolution (e.g., strong acid dissolution of QDs and gold nanoparticles). This method is ultrasensitive and its DL is low to 77fM. The simultaneous detection of multiple protein targets is easily performed by using different metal phosphate nanoparticle labels (cadmium phosphate and lead phosphate). This approach can be extended to prepare multiple metal (such as zinc, lead, ...

Science.gov (United States)

We report on the single-particle properties of lanthanide-ion doped oxide nanoparticles. We have demonstrated that their size can be accurately determined from their luminosity. The optically determined size distribution is in very good agreement with the distribution obtained from transmission electron microscopy (TEM). We also showed that the photobleaching of these nanoparticles is related to a reduction process and that we can use it to sense in a concentration-dependent manner the presence of an oxidant like H2O2. Finally, we propose a way to perform nanoparticle-protein coupling and to determine the protein-nanoparticle ratio at the single-particle level.

Science.gov (United States)

Spectral and energy luminescence characteristics of R6G dye solutions in ethanol with addition of Ag nanoparticle suspensions in different aggregate states are experimentally investigated. It is demonstrated that incorporation of non-aggregated and aggregated nanoparticles causes the superluminescence thresholds in R6G solutions to decrease. It is established that the optical properties of the laser beam propagation channel are transformed when low-power (20 mW) cw laser radiation passes through the suspension of nanoparticles. This is manifested through the occurrence of a region with enhanced nanoparticle density in the laser beam center, on which diffraction of laser radiation is observed.

Energy Technology Data Exchange (ETDEWEB)

Properties of photoconductive ultraviolet detectors fabricated on ZnO films were presented. Highly c-axis oriented ZnO films were grown on glass substrates by pulsed laser deposition. Ultraviolet photodetectors were fabricated based on metal-semiconductor-metal planar structures. The photoresponsivity and the quantum efficiency are much higher in the ultraviolet range than in the visible range, and the peak values are around 360 nm. Photocurrent transients show that the detector has a large photocurrent with the peak value of 2.8 mA, and a slow photoresponse with a rise time of 5 min and a decay time of 7 min. The response curve of the detector is fitted well with exponential curve. The large photocurrent should result from the both effects of the accumulation of conduction electrons and the decrease of the barrier height between crystallites. The relaxation time constant {tau} obtained from the curve fitting represents the time accumulation ...

International Nuclear Information System (INIS)

Glasses in the system (1 - x) [29Na2O- 4Al2O3- 67B2O3]- xZnO (0 ? x ? 35 mol%), have been prepared by the melt quenching technique. Elastic properties, X-ray and FT-IR spectroscopic studies have been employed to study the role of ZnO on the structure of the investigated glass system. Elastic properties and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz at room temperature. The results showed that the density increases and the molar volume decreases while both sound velocities and the determined glass transition temperatures decrease with increase in x. X-ray and infrared spectra of the glasses reveal that the borate network consists of diborate units and is affected by the increase in the concentration of ZnO content. These results are interpreted in terms of the decrease in the N4 values (fraction of tetrahedral coordinated boron atoms), and substitution of longer bond lengths of ...

International Nuclear Information System (INIS)

X-ray fluorescence analysis was used to determine the zinc content of the ''Perilacin'' powder and the ZnO content of the ''Epiderman-pix'' powder. The characteristic Ksub(#alpha#) line of zinc was excited using a "1"4"7Pm/Mo source (10"7 s"-"1) and the molybdenum Ksub(#alpha#) line (17.47 keV). 4 to 5% Zn and 45 to 49% ZnO were determined with a NaI(Tl) scintillation detector. The radiation intensity was found to decrease with particle size. (M.K.).

Science.gov (United States)

BackgroundIn recent years, near-infrared fluorescence (NIRF)-labeled iron nanoparticles have been synthesized and applied in a number of applications, including the labeling of human cells for monitoring the engraftment process, imaging tumors, sensoring the in vivo molecular environment surrounding nanoparticles and tracing their in vivo biodistribution. These studies demonstrate that NIRF-labeled iron nanoparticles provide an efficient probe for cell labeling. Furthermore, the in vivo imaging studies show excellent performance of the NIR fluorophores. However, there is a limited selection of NIRF-labeled iron nanoparticles with an optimal wavelength for imaging around 800 nm, where tissue autofluorescence is minimal. Therefore, it is necessary to develop additional alternative NIRF-labeled iron nanoparticles for application in this area.ResultsThis study manufactured 12-nm ...

International Nuclear Information System (INIS)

Inorganic nanoparticles are indispensable for science and technology as materials, pigments and cosmetics products. Improving the dispersion stability of nanoparticles in various liquids is essential for those applications. In this review, we discuss why it is difficult to control the stability of nanoparticles in liquids. We also overview the role of surface interaction between nanoparticles in their dispersion and characterization, e.g. by colloid probe atomic force microscopy (CP-AFM). Two types of surface modification concepts, post-synthesis and in situ modification, were investigated in many previous studies. Here, we focus on post-synthesis modification using adsorption of various kinds of polymer dispersants and surfactants on the particle surface, as well as surface chemical reactions of silane coupling agents. We discuss CP-AFM as a technique to analyze the surface interaction between ...

British Library Electronic Table of Contents (United Kingdom)

By choosing appropriate microemulsion systems, hexagonal cobalt (Co) and cobalt-nickel (1:1) alloy nanoparticles have been obtained with cetyltrimethylammonium bromide as a cationic surfactant at 500degreeC. This method thus stabilizes the hcp cobalt even at sizes (<10nm) at which normally fcc cobalt is predicted to be stable. On annealing the hcp cobalt nanoparticles in H2 at 700degreeC we could transform them to fcc cobalt nanoparticles. Microscopy studies show the formation of spherical nanoparticles of hexagonal and cubic forms of cobalt and Co-Ni (1:1) alloy nanoparticles with the average size of 4, 8 and 20nm, respectively. Electrochemical studies show that the catalytic property towards oxygen evolution is dependent on the applied voltage. At low voltage (less than 0.65V) the Co (he...

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The article deals with a novel electrochemical method of preparing long-lived silver nanoparticles suspended in aqueous solution as well as silver powders. The method does not involve the use of any chemical stabilising agents. The morphology of the silver nanoparticles obtained was studied using transmission electron microscopy, scanning electron microscopy, atomic force microscopy and dynamic light scattering measurements. Silver nanoparticles suspended in water solution that were produced by the present technique are nearly spherical and their size distribution lies in the range of 2 to 20 nm, the average size being about 7 nm. Silver nanoparticles synthesised by the proposed method were sufficiently stable for more than 7 years even under ambient conditions. Silver crystal growth on the surface of the cathode in the electrochemical process used was shown to result in micron-sized structures ...

UK PubMed Central (United Kingdom)

This work describes the synthesis and characterization of novel thermoresponsive highly-branched polyamidoamine-polyethylene glycol-poly (D, L-lactide) (PAMAM-PEG-PDLLA) core-shell nanoparticles....Full Text Available

UK PubMed Central (United Kingdom)

Responsive biomaterials play important roles in imaging, diagnostics, and therapeutics. Polymeric nanoparticles (NPs) containing hydrophobic and hydrophilic segments are one class of biomaterial...Full Text Available

Environmental Research Database

SummaryNanoparticles are increasingly being used in industry. Their potential to cause adverse health effects is due to their very small particles size (less than 100nm). A review is to be carried out to explore a) the use/release of nanoparticles in industry, b) current practices to control exposure and c) the potential levels of workplace exposure. The report will contain a discussion of what is current best practice to control exposure to nanoparticles. It will also indicate where the gaps in kn [continued...]ObjectivesA written report that draws upon disparate sources of available information and uses competent occupational hygiene expertise to form expert opinion on the implications. Key measures will the demonstration reasoned arguments supported by data from both current deliberate manufacturing of nanoparticles and incident nanoparticle production. The report will include ...

UK PubMed Central (United Kingdom)

The interior of 237 nm spherical vinylsilsesquioxane nanoparticles has been covalently modified and their surface functionalized under mild conditions to yield a novel type of hybrid silsesquioxane...Full Text Available

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is fabrication and characterization of silver nanofluid by the submerged arc nanoparticle synthesis system (SANSS). The silver metal electrodes under the electrical discharge will melt and evaporate rapidly and condense to form the nanoparticles in the lower temperature dielectric liquid and produce the suspended nanoparticle. The results showed that the spherical nanosilver particle formed in the ethylene glycol and the mean particle size is about 12.5 nm. The prepared silver nanofluid was irradiated under the 410 nm visible light, electrons could be excited from the valence band to the conduction band. The silver nanofluid more closely resembles Newtonian fluids.

Science.gov (United States)

We have demonstrated fluorescence resonance energy transfer (FRET) between lanthanide-ion doped oxide nanoparticles acting as donors and organic acceptor molecules (Cy5). Due to the long nanoparticle lifetime and the large Stokes shift between nanoparticle absorption and emission, unambiguous and precise FRET measurements can be performed despite the presence of large free acceptor oncentrations. We determined FRET efficiencies as a function of Cy5 concentration which are in very good agreement with a multiple acceptor-multiple donor calculation.

British Library Electronic Table of Contents (United Kingdom)

Solar syngas production from CO"2 and H"2O is considered in a two-step thermochemical cycle via Zn/ZnO redox reactions, encompassing: 1) the ZnO thermolysis to Zn and O"2 using concentrated solar radiation as the source of process heat, and 2) Zn reacting with mixtures of H"2O and CO"2 yielding high-quality syngas (mainly H"2 and CO) and ZnO; the ZnO is recycled to the first, solar step, resulting in net reaction @bCO"2 + (1 - @b)H"2O -> @bCO + (1 - @b)H"2. Syngas is further processed to liquid hydrocarbon fuels via Fischer-Tropsch or other catalytic processes. Second-law thermodynamic analysis is applied to determine the cycle efficiencies attainable with and without heat recuperation for varying molar fractions of CO"2:H"2O and solar reactor temperatures in the range 1900-2300 K. Conside...

Science.gov (United States)

... Figure 3a. PETN Filled Tube Specimen Detonated by Exploding Bridgewire Specimen POLYETIILLENE END-CAP "1- 901am WALL IHICKNESS ...

Science.gov (United States)

Guidelines for the viability primer component of the version 3 workbook. The Viability page in the current version of the Excel spreadsheet for conservation ... ...

Science.gov (United States)

This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change ... ...

Energy Technology Data Exchange (ETDEWEB)

Formulae are obtained for the angular correlation function of inelastically scattered ..cap alpha.. particles and ..gamma.. quanta of a pure EL multipolarity, which are emitted by an excited nucleus, in the case of exchange processes, if distortions are introduced into the eikonal approximation. The matrix element of the exchange processes is considered as a coherent sum of contributions from two mechanisms: replacement and stripping of a heavy particle. Concrete calculations are performed for the reaction /sup 12/C(..cap alpha.., ..cap alpha..'..gamma..)/sup 12/C. The obtained results show that the developed formalism enables one to get an agreement between the theoretical angular correlation functions with the experimental data at reasonable values of the calculation parameters.

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In this paper we describe a fractal assembly of copper nanoparticles on different substrates by controlling the chemical replacement reaction. Through calculation, we found that the 'fractal dimensions' of copper dendrites synthesized by us were about 1.832, which agreed well with the 'fractal dimensions' of natural fern leaves (fractal dimension, 1.826), suggesting that the fern fractal model was useful to describe the self-assembly of our copper nanoparticles during the chemical replacement reaction process. These results will be beneficial for the understanding of the role that highly nonequilibrium conditions play in the formation of fractal clusters as well as the self-assembly mystique of metallic nanoparticles in nonequilibrium conditions and also helpful in the future assembly of complicated nanoarchitectures of metallic nanoparticles for potential ...

British Library Electronic Table of Contents (United Kingdom)

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

Energy Technology Data Exchange (ETDEWEB)

We demonstrate that the nanoparticle formation during laser ablation of metals by short (of a few tens of ps) laser pulses strongly depends on the concentration of surrounding gas. While, at vacuum conditions, nanoparticle formation shows very ''sharp'' atomic force microscope images of aggregated clusters, following with clear appearance of plasmon resonance on the absorption spectra of deposited films, an addition of gas particles starts to decrease the probability of cluster formation. This process shows a threshold for both helium (33 torr) and xenon (12 torr) above which no surface plasmon resonance and correspondingly no observable nanoparticles on the deposited surfaces were detected. The destruction of nanoparticle formation was attributed to the negative influence of surrounding gas particles on ablated particles aggregation. (orig.)

International Nuclear Information System (INIS)

We described the use of silica nanoparticles as building blocks for the immobilization of electrogenerated chemiluminescence (ECL) reagent Ru(bpy)_3"2"+ and the fabrication of layer-by-layer assembly film by alternating the deposition of the Ru(bpy)_3"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)_3"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)

Gold nanoparticles were synthesized by using banana peel extract (BPE) as a simple, non-toxic, eco-friendly 'green material'. The boiled, crushed, acetone precipitated, air-dried peel powder was used to reduce chloroauric acid. A variety of nanoparticles were formed when the reaction conditions were altered with respect to pH, BPE content, chloroauric acid concentration and temperature of incubation. The reaction mixtures displayed vivid colors and UV-vis spectra characteristic of gold nanoparticles. Dynamic light scattering (DLS) studies revealed that the average size of the nanoparticles under standard synthetic conditions was around 300nm. Scanning electron microscopy and energy dispersive spectrometry (EDS) confirmed these results. A coffee ring phenomenon, led to the aggregation of th...

Science.gov (United States)

The liquid-phase synthesis of metal oxide nanoparticles in organic solvents under exclusion of water is nowadays a well-established alternative to aqueous sol-gel chemistry. In this article, we highlight some of the advantages of these routes based on selected examples. The first part reviews some recent developments in the synthesis of ternary metal oxide nanoparticles by surfactant-free nonaqueous sol-gel routes, followed by the discussion of the morphology-controlled synthesis of lanthanum hydroxide nanoparticles, and the presentation of structural peculiarities of manganese oxide nanoparticles with an ordered Mn vacancy superstructure. These examples show that nonaqueous systems, on the one hand, allow the preparation of compositionally complex oxides, and, on the other hand, make use of the organic components (initially present or formed in situ) in the reaction mixture to tailor the morphology. ...

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Highly water-repellent surfaces have been prepared from arrayed nanowires of zinc oxide (ZnO) by a treatment with stearic acid. The layers are electrochemically deposited on a nanocrystalline seed layer from an oxygenated aqueous zinc chloride solution. An advancing contact angle (CA) as high as 176{sup 0} is obtained with a very small hysteresis {approx}1{sup 0}. These results, supplemented by infrared spectroscopy, show that the stearic acid forms a very well-packed self-assembled monolayer. The CA measurements show a very good stability of the treated surface even when exposed to harsh conditions or long-term ambient illumination.

UK PubMed Central (United Kingdom)

CAP18 (an 18-kDa cationic antimicrobial protein) is a granulocyte-derived protein that can bind lipopolysaccharide (LPS) and inhibit various activities of LPS in vitro. The present study examined the...Full Text Available

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The study by impedance and photoelectrochemical measurements of passive films formed on an AISI 304 type stainless steel shows that important parameters of the electronic structure of these films are modified under ..cap alpha.. irradiation, namely: width of the space charge region, donors concentration and diffusion length for minority carriers. The consequences of ..cap alpha.. irradiation on localized corrosion processes are discussed.

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Chemical influences on the relative Ksub(..beta..)/Ksub(..cap alpha..) x-ray intensity ratio up to five per cent were found for different chemical constitutions of Cr, Mn, Fe and Cu by very precise PIXE measurements. In the discussion of these effects, screening of 3p electrons by a varying 3d valence charge, as well as polarizational effects are of importance.

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When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles ...

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The fluorescent behaviour and the photodynamic effect was studied in native and structurally modified lysozyme and ..cap alpha..-lactalbumin. The Tyr residues in lysozyme and ..cap alpha..-lactalbumin show different sensitivities to the photodynamic effect. The effect is zero in the case of Tyr from native lysozyme. In contrast, the Tyr residues in ..cap alpha..-lactalbumin are susceptible to photooxidation, which indicates a greater degree of exposure to the solvent. The three His residues of ..cap alpha..-lactalbumin have different degrees of exposure and show two different kinetics of photooxidation whereas the His residue of lysozyme is photooxidized with a single kinetic. Two photooxidation kinetics were obtained for the Trp residues of both native proteins, an indication that in both cases there are Trp residues that are differently exposed to the solvent. The wavelengths of maximum fluorescent ...

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Blood flow changes in the periodontal ligament (PDL) were measured indirectly by monitoring the local clearance of /sup 125/I/sup -/ during electric sympathetic nerve stimulation or close intra-arterial infusions of either noradrenaline (NA) or adrenaline (ADR) before and after administration of phentolamine (PA), phenoxybenzamine (PBZ) or Idazoxan (RX). At the doses used in the present study, PA was the only antagonist that significantly reduced the blood flow decrease seen on activation of sympathetic fibers, although PBZ also reduced this response. Idazoxan, however, did not induce the consistent effect on blood flow decreases seen on sympathetic activation. All three ..cap alpha..-adrenoceptor antagonists almost abolished the effects of exogenously administered NA and ADR. The results suggest the presence of functional post-junctional adrenoceptors of both the ..cap alpha.. 1 and ..cap alpha.. 2 subtypes in the ...

International Nuclear Information System (INIS)

A radiometric method was elaborated for surface density determinations of the adhesive layer of plasters by radionuclide X-ray fluorescence using the 17.47 keV bremsstrahlung of "1"4"7Pm/Mo. The bremsstrahlung line excites the 8.63 keV characteristic K#alpha# line of Zn contained in the adhesive layer of the plaster as a filling material in the form of ZnO. In homogeneous adhesive layers the Zn content is proportional to surface density. (author).

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Gold and silver nanoparticles display extraordinarily large apparent refractive indices near their plasmon resonance (PR) wavelengths. These nanoparticles show good contrast in a narrow spectral band but are poorly resolved at other wavelengths in differential interference contrast (DIC) microscopy. The wavelength dependence of DIC contrast of gold/silver nanoparticles is interpreted in terms of Mie's theory and DIC working principles. We further exploit this wavelength dependence by modifying a DIC microscope to enable simultaneous imaging at two wavelengths. We demonstrate that gold/silver nanoparticles immobilized on the same glass slides through hybridization can be differentiated and imaged separately. High-contrast, video-rate images of living cells can be recorded both with and without illuminating the gold nanoparticle probes, providing definitive probe ...

International Nuclear Information System (INIS)

Studying the structure of nanoparticles as a function of their size requires a correlation between the image and the diffraction pattern of single nanoparticles. Nanobeam diffraction technique is generally used but requires long and tedious TEM investigations, particularly when nanoparticles are randomly oriented on an amorphous substrate. We bring a new development to this structural study by controlling the nanoprobe of the Bright and Dark Field STEM (BF/DF STEM) modes of the TEM. The particularity of our experiment is to make the STEM nanoprobe parallel (probe size 1 nm and convergence angle <1 mrad) using a fine tuning of the focal lengths of the microscope illumination lenses. The accurate control of the beam position offered by this technique allowed us to obtain diffraction patterns of many single nanoparticles selected in the digital STEM image. By means of this technique, we demonstrate size ...

Science.gov (United States)

We presented a simple approach for in-situ synthesis of poly(dimethylsiloxane) (PDMS)-gold nanoparticles composite film based on the special characteristics of PDMS itself. It is an environmentally safe synthesis method without the requirement of additional reducing/stabilizing agents. The region where the resulting gold nanoparticles distribute (in the matrix or on the surface of the polymer) and the size of the nanoparticles, as well as the colour of the free-standing films, can be simply controlled by adjusting the ratio of curing agent and the PDMS monomer. The chemical and optical properties of these composite films were studied. Using such a method, gold nanoparticle micropatterns on PDMS surfaces can be performed. And based on the gold nanoparticles micropattern, further modification with antibodies, antigens, enzymes and other biomolecules can be achieved. To verify this ...

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CuAg core-shell nanoparticles are synthesized by ultra-high vacuum thermal evaporation. We show on this system how the Energy-Filtered Transmission Electron Microscopy (EFTEM) technique allows one to improve the characterization by precisely pointing out the formation of core-shell arrangements in bimetallic nanoparticle assemblies. A criterion to measure the shell thickness from EFTEM images on unique core-shell nanoparticles is defined, that can be used for core-shell nanoparticles of any sizes, with shell thicknesses over 1 nm. It is based on the intensity variation along a line drawn across a core-shell nanoparticle on a EFTEM image. This criterion has been validated by a close comparison of the shell thickness measurements performed in this work and the ones obtained by acoustic micro-Raman spectroscopy. Using this criterion, we report a strong correlation between the size of ...

Science.gov (United States)

Magnetic drug targeting, using core-shell magnetic carrier particles loaded with anti-cancer drugs, is an emerging and significant method of cancer treatment. Gold shell-iron core nanoparticles (Fe@Au) were synthesized by the reverse micelle method with aqueous reactants, surfactant, co-surfactant and oil phase. XRD, XPS, TEM and magnetic property measurements were utilized to characterize these core-shell nanoparticles. Magnetic measurements showed that the particles were superparamagnetic at room temperature and that the saturation magnetization decreased with increasing gold concentration. The anti-cancer drug doxorubicin (DOX) was loaded onto these Fe@Au nanoparticle carriers and the drug release profiles showed that upto 25% of adsorbed drug was released in 80 h. It was found that the amine (-NH2) group of DOX binds to the gold shell. An in vitro apparatus simulating the human circulatory system was used to determine ...

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We demonstrate the rapid optical characterization of large numbers of individual metal nanoparticles freely diffusing in colloidal solution by confocal laser spectroscopy. We find that hollow gold nanospheres and solid silver nanoparticles linked with a bifunctional ligand, both designed nanostructures, exhibit significantly higher monodispersity in their Rayleigh and Raman scattering response than randomly aggregated gold and silver nanoparticles. We show that measurements of rotational diffusion timescales allow sizing of particles significantly more reliably than can be obtained using translational diffusion timescales.

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Electron paramagnetic resonance was used to investigate surface-coated magnetite-based magnetic fluids doped with TEMPOL. Two magnetic fluid samples, having magnetite nanoparticles with average diameter of 94 A and coated with different coating layers (lauric acid plus ethoxylated polyalcohol in one case and oleoylsarcosine in the other case), were doped with TEMPOL (6 mM and pH 7.4) and investigated as a function of the nanoparticle concentration. The resonance field and the resonance linewidth both scale linearly with the nanoparticle concentration.

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The variation of surface composition and sintering of the binary Pd{sub 7}Ag{sub 3} nanoparticles prepared by chemical reduction were studied. The composition of the as-prepared Pd{sub 7}Ag{sub 3} nanoparticles across the diameter is inhomogeneous due to different reduction potentials of Pd and Ag. Upon heating, Ag will migrate to the surface because of its lower surface energy. Surface modification results in variation of surface composition during the sintering process. Stearic acid acts as a grain growth inhibitor. The migration of Ag to the surface is suppressed and the sintering is retarded. Modification by polyethylene glycol leads to more migration of Ag atoms from the core to the surface. This makes the nanoparticles easier to sinter.

British Library Electronic Table of Contents (United Kingdom)

Highly dispersed silver nanoparticles embedded in mesoporous thin films (MTFs) have been synthesized by modification of the interior surface of mesoporous silica with ethylenediamine moieties, which provided the coordination sites for the Ag ions, and subsequent reduction under hydrogen atmosphere. TEM observations show the mesoporous parent films have effectively controlled the growth of the synthesized silver nanoparticles. The composite films had an ultrafast nonlinear response time, as fast as 200 fs, and a third-order nonlinear optical susceptibility of 0.94??10?10 esu, which was enhanced by the local field enhancement effect that was present when the silver nanoparticles were embedded in the surrounding dielectric matrix. The origin of the ultrafast nonlinear response and the enhanc...

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Metallic nanoparticles was synthesized in SiO{sub 2} matrices by means of a process of two stages. The first one proceeded via sol-gel, incorporating the metallic precursors to the reaction system before the solidification of the matrix. Later on, the samples underwent a thermal treatment in atmosphere of H{sub 2}, carrying out the reduction of the metals that finally formed to the nanoparticles. Then it was detected the presence of smaller nanoparticles than 20 nm, dispersed and with the property of being liberated easily of the matrix, conserving a free surface, chemically reactive and with response to external electromagnetic radiation. The system SiO{sub 2}-Pd showed an important thermoluminescent response. (Author)

British Library Electronic Table of Contents (United Kingdom)

Size-controllable Ag nanoparticle ultrathin films, which were fabricated by vacuum deposition method from high purity Ag wire onto cleaned indium tin oxide conducting glass, have different color fabricated by variation of preparation conditions. The UV/Vis spectra showed that optical absorption peak of these Ag nanoparticle films can be tuned in a range from 457nm to >650nm. Scanning electron microscopy images showed that with increasing film thickness Ag particle size was larger. Ag/WO3 composite films were prepared by cathodic electrodeposition of WO3 onto the surface of Ag nanoparticle films. Spectroelectrochemistry and electrochromic properties of the resulting composite films were characterized. It was found that the electrochemical and electrochromatic properties of the composite fil...

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The rapid growth in the use of in vitro methods for nanoparticle toxicity assessment has proceeded with limited consideration of the unique kinetics of these materials in solution. Particles in general and nanoparticles specifically, diffuse, settle and agglomerate in cell culture media as a function of several systemic and particle factors: media density and viscosity, particle size, shape and density. Cellular dose then is also a function of these factors as they determine the rate of transport of nanoparticles to cells in culture. Here we develop and apply the principles of particokinetics and dosimetry in vitro and outline an approach for simulation of nanoparticle particokinetics in cell culture systems. We illustrate that where equal mass concentrations (?g/ml) imply equal doses for dissimilar materials, the corresponding particle number or surface area concentration doses differ by orders of ...

Science.gov (United States)

... metal-oleate complexes. At this point, this method has been reported only for iron nanoparticles [15]. We have demonstrated ...

British Library Electronic Table of Contents (United Kingdom)

The addition of ?-Sialon nanoparticles to lubricants in heavy-duty frictional joints is shown to be effective.

Science.gov (United States)

... The MTT assay indicates cell viability through a yellow to purple ... besiegers were said to have catapulted plague infected corpses into the city of ...

British Library Electronic Table of Contents (United Kingdom)

The formation of nanoparticles during the radiation-induced chemical reduction of silver ions, copper ions, and nickel ions in films based on poly(acrylic acid)-poly(ethylenimine) complexes are studied via electron microscopy. This approach allows preparation of composites containing nanoparticles that are randomly distributed in the polymer matrix and materials with a regular spatial distribution of nanoparticles across the film thickness and in subsurface layers. The structure of metal-polymer hybrid materials is dependent on the irradiation conditions, the type of reduced metal ions, and their initial content in polymer matrices. The ratio between the rate of nucleation and the rate of growth of nanoparticles in the matrices of interpolyelectrolyte complexes depends on the intensity of ...

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The objective of this research project is to investigate the biocompatibility of N-isopropylacrylamide (NIPAAm) monomers and poly(N-isopropylacrylamide) (PNIPAAm) nanoparticles in vitro. PNIPAAm nanoparticles of different sizes were synthesized and characterized by transmission electron microscopy and dynamic light scattering. Cytotoxicity studies using MTS assays were conducted on fibroblasts, smooth muscle cells, and endothelial cells. In addition, the concentration of NIPAAm monomers remaining on PNIPAAm nanoparticles was determined using bromination and spectrophotometry. The cytotoxicity results did not show a significant difference in cell survival when cells were exposed to different particle sizes (100, 300, and 500 nm). Dose studies showed that all three cell types exposed to 100 nm PNIPAAm nanoparticles at concentrations less than or equal to 5 mg/mL were compatible, while cells exposed to ...

Science.gov (United States)

This suggests that Ms of the iron nanoparticles is about 125 emu/g, about half of M~u.lk, which contradicts previous reports on transition metals. ...

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Correlation between mechanical stress and hydrogen effects on radiation damage in polycide-gate MOS capacitors was investigated as a function of gate-oxide thickness. The compressive stress magnitude was altered by varying the silicide (TiSi/sub 2/ or WSi/sub 2/) thickness in the polycide-gate electrode, and hydrogen introduction into gate-SiO/sub 2/ film was carried out by diffusion from plasma-deposited silicon-nitride passivation film (SiN-Cap). In a MOS capacitor without passivation film (No-Cap sample), it was found that compressive stress on gate-SiO/sub 2/ reduces both positive charge build-up (..delta..Qot) and interface-trap generation (..delta..Dit). Radiation induced shift, ..delta..Qot exhibits a smaller stress effect as compared with ..delta..Dit. As gate-SiO/sub 2/ thickness decreases, the stress effect on ..delta..Qot increases, while this effect on ..delta..Dit remains nearly constant. This compressive stress effect was ...

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The K/sub ..beta..//K/sub ..cap alpha../ X-ray intensity ratios are measured for Mn and Fe and for six other elements with Z lying in the range 49 less than or equal to Z less than or equal to 82 following electron capture decay and photon excitation using /sup 241/Am and /sup 57/Co sources. High-resolution Si(Li) and HpGe detector systems were used in the experiments. The dependence of K/sub ..beta..//K/sub ..cap alpha../ values on the mode of excitation in the case of Mn and Fe is attributed to chemical effects, while no such dependence is found for the high-Z elements.

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In 2001, the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA/NSO) remediated six areas associated with Amchitka mud pit release sites located on Amchitka Island, Alaska. This included the construction of seven closure caps. To ensure the integrity and effectiveness of remedial action, the mud pit sites are to be inspected every five years as part of DOE's long-term monitoring and surveillance program. In August of 2006, the closure caps were inspected in accordance with the ''Post-Closure Monitoring and Inspection Plan for Amchitka Island Mud Pit Release Sites'' (Rev. 0, November 2005). This post-closure monitoring report provides the 2006 cap inspection results.

UK PubMed Central (United Kingdom)

Zinc tetraaminophthalocyanine-Fe₃O₄ nanoparticle composites were prepared by organic-inorganic complex technology and characterized. It has been proved that the ZnTAPc dispersed...Full Text Available

UK PubMed Central (United Kingdom)

The aim of this study is to determine the effects of silver nanoparticles (Ag-NP) on vascular endothelial growth factor (VEGF)-and interleukin-1 beta (IL-1β)-induced vascular permeability, and...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

This comprehensive, critical review summarizes the use of nanoparticles in enhanced and amplified chemiluminescence detection, illustrated by different reaction strategies, electrogenerated chemiluminescence sensors, immunoassay or hybridization labels and electrogenerated chemiluminescence immunoassay or hybridization sensors. We discuss the analytical applications on the basis of validity, range and sensitivity, and draw some useful conclusions about the most sensitive approach in each type of application.

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A microemulsion comprised of water, Brij 78, pentanol and styrene into which PPO and bis-MSB had been dissolved was prepared. Polymerization of the styrene resulted in a suspension of fluor-containing polystyrene nanoparticles (<100 nm). After a concentration step, the aqueous nanosuspension was able to detect {sup 14}C with counting efficiencies over 50% of those of a commercially available scintillation cocktail. Monte Carlo calculations demonstrated that the size and concentration of the nanoparticles were appropriate for optimum detection efficiency.

UK PubMed Central (United Kingdom)

Purpose of ReviewThe vertebrate cap’n’collar family transcription factor Nrf2 and its invertebrate homologs SKN-1 (in worms) and CncC (in flies) function...Full Text Available

Science.gov (United States)

... t.., tt:,tifv! th - cui,nt !shor tfal 1 in breaching capAbiii tN wi h i- 1!,-ia . ~ ... Before the 1967 war, the Israeli Training ... trained Arab opponents. ...

UK PubMed Central (United Kingdom)

BACKGROUNDProtocadherin-PC (PCDH-PC) expression is upregulated in apoptosis-resistant sublines of the LNCaP human prostate cancer (CaP) cell line. Here, we assess...Full Text Available

Science.gov (United States)

The results of a study of the expression of embryonic hemoglobin genes in mice which show an imbalance of alpha and non-alpha chain synthesis are reported. (ACR)

UK PubMed Central (United Kingdom)

BackgroundFor the detection of allergen-specific IgE in sera, solid-phase IgE-binding assays like the CAP test are commonly used. Although such immunochemical methods are very sensitive,...Full Text Available

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Using {gamma}-irradiation-induced reduction in the field of a {sup 60}Co {gamma}-ray source, colloidal silver and gold nanoparticles were prepared from their corresponding metal salts in aqueous solution and compared with those by chemical reduction. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those obtained by chemical reduction method while there was no significant difference between the two strategies for the preparation of gold nanoparticles. {gamma}-Irradiation of 1.0 x 10{sup -3} M AgNO{sub 3} solution resulted in nearly 100 times more highly concentrated silver colloids than those by citrate reduction. Furthermore, the radiation method could lead to more highly concentrated silver colloids by simply increasing the concentration of AgNO{sub 3} solution up to 2.0 x 10{sup -2} M. The two metal nanoparticles prepared by the ...

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There has been considerable interest in producing and studying nanoparticle materials because of the effect of size on their structure, physical and chemical structure. Most studied nanoparticle semiconductors belong to the II-VI group, as they are relatively easy to synthesize and are generally prepared as particulates or in thin film form. Among II-VI compounds, CdS is one of the most studied materials. There are different ways to synthesize CdS nanoparticles such as colloidal particles, chemical decomposition, sol-gel, gas evaporation, magnetron sputtering, electrostatic deposition, and etc. {gamma}-irradiation is one of the effective methods for synthesis of nanomaterials. These nonomaterials have been extensively used in the preparation of nanocrystalline metals, metal oxides, and metal-polymer composites. However, The preparation of CdS nanoparticle and CdS/ polyacrylonitrile nanocomposite by ...

International Nuclear Information System (INIS)

Functionalizing nanoparticle surfaces is essential for achieving homogeneous dispersions of monodisperse particles in polymer nanocomposites for successful utilization in engineering applications. Functionalization reduces the surface energy of the nanoparticles, thereby limiting the tendency to agglomerate. Moreover, reactive groups on the surface can also participate in the polymerization, creating covalent bonds between the inorganic and organic phases. In this paper, a fluidized bed inductively coupled plasma (FB-ICP) reactor is used to break apart the agglomerates and functionalize commercial TiO2 nanoparticle powders in a batch of several grams. The fluidized bed could be implemented into a continuous flow reactor, potentially making this a viable method to treat larger quantities of commercial powders. The particles are treated with acrylic acid (AA) and tetraethylorthosilicate (TEOS) plasma and the functionalized ...

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Carbon supported catalysts can lose their activity over a period of time due to the sintering of the nanometer-sized catalyst particles. The sintering of metal clusters on carbon supports can occur due to the weak interaction between the metal and the support and also due to the corrosion of carbon, especially in fuel cell electrocatalysts. The sintering may be reduced by increasing the interaction between the metal and the support and also by increasing the corrosion resistance of carbon supports. In an effort to mitigate the growth of the nanoparticles, carbon-substituted boron defects were introduced in the carbon lattice. The interaction between the Pt nanoparticles on the pure and boron-doped carbon supports was examined using X-ray photoelectron spectroscopy (XPS). The results indicate that the interaction between the Pt nanoparticles and the boron-doped carbon support was slightly stronger than the interaction ...

International Nuclear Information System (INIS)

HgTe rod-shape composed of crystalline particles has been prepared by a hydrothermal method, and characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transition electron microscopy (TEM). The effects of capping agents, reductants, reaction temperatures, and reaction times on crystal structures and shapes of HgTe have been investigated. The results showed that the CTAB as capping agent plays a crucial role in the hydrothermal process. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods.

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We calculate the cross section for the resonance scattering of Lyman-..cap alpha.. radiation by spinless nonrelativistic hydrogen atoms in the ground state using a two-level model. A generalization of Dirac's resonance scattering theory is used together with the exact matrix elements for the electromagnetic interaction. In contrast to the usual treatments in which only the dipole approximation for the matrix elements are taken, the shift in position of the resonance is finite and has a value of 75% of the Lamb shift of the n=1 state. Whether this latter fact is significant in renormalization calculations is left open.

CERN Document Server

If (S,h) is an open book with disconnected binding then we can form a new open book (S',h') by capping off one of the boundary components of S with a disk. We define a U-equivariant map on Heegaard Floer homology which sends c^+(S',h') to c^+(S,h), and we discuss various applications. In particular, we compute the 3-dimensional invariant associated to any contact structure with non-vanishing contact invariant which is compatible with a genus one open book with periodic monodromy.

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

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The addition of ZnO, depleted in the Zn-64 isotope, to the water of boiling water nuclear reactors lessens the accumulation of Co-60 on the reactor interior surfaces, reduces radioactive wastes and increases the reactor service-life because of the inhibitory action of zinc on inter-granular stress corrosion cracking. To the same effect depleted zinc in the form of acetate dihydrate is used in pressurized water reactors. Gas centrifuge isotope separation method is applied for production of depleted zinc on the industrial scale. More than 20 years of depleted zinc application history demonstrates its benefits for reduction of NPP personnel radiation exposure and combating construction materials corrosion.

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In this work, ZnO thin films have been grown on glass substrates by using a solution of propanol (C{sub 3}H{sub 8}O), water (H{sub 2}O) and zinc acetate (Z{sub n}(CH{sub 3}CO{sub 2}){sub 2}) in acidified medium (pH 5). The obtained films were n doped with ytterbium (Yb) at the rates of 100, 200 and 300 ppm. The structural features of the doped films were investigated using XRD, atomic force microscopy and scanning electronic microscopy techniques. XRD analysis shows a strong (0 0 2) X-ray diffraction line for increasing Yb-doping amounts. This c-axis preferential orientation of ZnO crystallites is naturally required to use this oxide as transparent conductor in optoelectronic applications. Atomic force microscopy (AFM) analysis shows an enhancement in the surface roughness of the doped ZnO:Yb thin films. Optical measurements were performed in 300-1800 nm domain via transmittance T(lambda) and reflectance R(lambda) spectra. Conjoint optical and ...

International Nuclear Information System (INIS)

Nuclear Reaction Analysis (NRA) with deuteron ion beams has been used to probe for ion implanted nitrogen and carbon with high sensitivity in zinc oxide and silicon single crystals. The ion implanted N was measured using 1.4 MeV deuteron ion beams and was found to be in agreement with calculated values. The limit of detection for N in ZnO is 8x1014 ions cm-2. Raman measurements of the ion implanted samples showed three additional modes at 275, 504, and 644 cm-1 compared to the un-implanted ZnO crystals. The NRA and Raman results provided information on the N concentration, depth distribution, and structural changes that occur in dependence on the nitrogen ion fluences. The deuterium induced 12C(d,p)13C reaction was used to measure the carbon impurity/dose in ion implanted silicon. It was found that the use of a large cold shield (liquid nitrogen trap) in the ion implanter chamber greatly reduces the amount of carbon impurity on the surface of ...

Science.gov (United States)

In the present work, a new kind of myoglobin (Mb)/Au nanoparticles composite film was fabricated on pyrolytic graphite (PG) electrodes. Oppositely charged chitosan (CS) and silica (SiO(2)) nanoparticles were alternately adsorbed on the PG surface by the electrostatic interaction between them, forming {CS/SiO(2)}(5) layer-by-layer films. Mb and HAuCl(4) in solution were then simultaneously loaded into {CS/SiO(2)}(5) films. The loaded Au(III) in the films were electrochemically reduced into Au nanoparticles, forming nanocomposite films, designated as {CS/SiO(2)}(5)-Mb-Au. Various techniques such as cyclic voltammetry (CV), square wave voltammetry (SWV), quartz crystal microbalance (QCM), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis were used to characterize the films. Compared with {CS/SiO(2)}(5)-Mb films without Au ...

International Nuclear Information System (INIS)

Silica glasses containing Pr"3"+ with and without CdS nanoparticles were prepared by sol-gel technique. The influence of CdS nanoparticles on Pr"3"+ doped glass was studied by absorption, photoluminescence and up-conversion. From the measured intensities of various absorption bands of these glasses, the Judd-Ofelt parameters ?_2, ?_4 and ?_6 have been evaluated. The radiative transition probability (A), radiative lifetime (?_R), branching ratio (?_R) and integrated emission cross-section (?_P) were calculated from excited states of "3P_1 and "3P_0 levels. The up-conversion emissions were found in the green, orange and red regions under 800 nm excitation with peaks 559, 612 and 688 nm respectively. On excitation with 370 nm also leads to similar green, orange and red regions.

Energy Technology Data Exchange (ETDEWEB)

A detailed comparison of the softness of gold and silver has been reported in the light of hard soft acid base (HSAB) principle. Gold and silver nanoparticles in organic media (i.e., organosol) have been exploited individually to establish the principle. Sulfur and nitrogen were employed as soft and borderline donating atoms to examine the metal-ligand interactions. In this regard, thiols and amines have been considered as interacting ligands with sulfur and nitrogen donor atoms respectively. The stronger affinity of gold towards softer sulfur donor as compared to nitrogen and conversely a reasonable interaction of silver nanoparticles with both the atoms authenticate the softer nature of gold nanoparticle as compared to silver one.

International Nuclear Information System (INIS)

The structure of nano-porous carbon, obtained by means of chlorination of carbide compounds with various crystal structure (SiC, TiC, Mo_2C) is studied through the method of small-angle diffraction. The angular dependences of the scattering intensity obtained are interpreted as the result of scattering from the nanoparticles of different size. The functions of the scattering particles distribution by the m(R_g) inertia radii are determined. It is shown that in spite of the source carbide, the highest fraction of the volume in the porous carbon constitute the particles with R_g #approx# 5 A. The nanoparticles in the samples obtained from SiC, wherein the average value of the R_g"a"v < 6 A, are most uniform by size. The nanoparticles in the porous carbon, obtained from Mo_2C, are on the average by two times larger

International Nuclear Information System (INIS)

We report on the fabrication of nanomechanical devices for shuttling of electrons from one electrode to another. Each device consists of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes. In two different kinds of shuttle-junctions the nanoparticle is attached to the electrodes through either (i) a single layer of 1,8-octanedithiol or (ii) a multilayer of 1-octanethiol molecules. The thiol layers play the role of 'damped springs', such that when a sufficient voltage bias is applied to the junction, the nanoparticle is expected to start oscillating and thereby transferring electrons from one electrode to the other. For both kinds of shuttle-junctions we observed an abrupt increase in the transmitted current above a threshold voltage, which can be attributed to a transition from the stationary to the oscillating regime. The threshold voltage was found to be lower for single-layer ...

International Nuclear Information System (INIS)

We report studies of bimetallic nanoparticles with 15%-16% atomic crystal parameters size mismatch. The degree of alloying was probed in a 2-nm Pt core (smallest attainable core size) of Pt-Ag nanoparticles (completely immiscible in bulk) and 20-nm-diameter Pd-Ag nanowires (completely miscible in bulk). Particles were synthesized radiolytically, and depending on the initial parameters, they assume spherical or cylindrical (nanowire) morphologies. In all cases, the metals are seen to follow their bulk alloying characteristics. Pt and Ag segregate in both spherical and wire forms, which indicates that strain due to crystallographic mismatch overcomes the excess surface free energy in the small particles. The Pd-Ag nanowires alloy similar to previously reported spherical Pd-Ag particles of similar diameter and composition.

Energy Technology Data Exchange (ETDEWEB)

A comparison between chicken and rat lung was made for microsomal prostaglandin (PG) synthesis from 1-/sup 14/C-arachidonic acid. Microsomal protein (2.0 mg) from chicken or rat lung was incubated in the presence of 20 ..mu..g of 1-/sup 14/C-arachidonic acid (specific activity = 3 x 10/sup 6/ dpm/..mu..mol for chicken; 6 x 10/sup 6/ dpm/..mu..mol for rat), 0.05 M Tris-HCl buffer (pH = 8.0), 0.5 mM epinephrine, and 1 mM reduced glutathione in a total volume of 0.5 ml in a 37/sup 0/C water bath with shaking for 15 min. After acidification with 1 M HCl to pH 3, prostaglandins were extracted with ethyl acetate. The products of the reactions were separated by reversed phase chromatography, and the radioactivity of each prostanoid fraction was determined. The predominant prostanoid synthesized by chicken lung microsomes was PGE/sub 2/, followed by much lower amounts of thromboxane B/sub 2/ (TXB/sub 2/), PGF/sub 2//sub ..cap alpha../ and PGD/sub 2/. In at lung, ...

Energy Technology Data Exchange (ETDEWEB)

The effect that different chemical and physical atomic environments can have on the relative intensities of radiative electron transitions from the filling of K shell vacancies was investigated. The method used involved the detection of photoionization induced X-ray fluorescence. An experimental system based on a hyper pure germanium detector (HPGE) was used to measure the relative K-L and K-M X-ray yields from the photofluorescence of a series of lanthanide elements and compounds. A background subtraction and peak integration strategy was employed which accounted for scattering in the samples and scattering of the flux from the radioisotope photoionization sources. Analysis of the data resulted in a tabulation of relative K/sub ..beta..//K/sub ..cap alpha../ X-ray intensity ratios. The measured relative K/sub ..beta..//K/sub ..cap alpha../ X-ray intensity ratios were compared to the calculated values predicted by the theoretical development of ...

UK PubMed Central (United Kingdom)

During the last few years, research on toxicologically relevant properties of engineered nanoparticles has increased tremendously. A number of international research projects and additional activities...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

We demonstrate a preparative method which produces highly-monodisperse Pt-nanoparticles of tunable size without the external addition of seed particles. Hexachloroplatinic acid is dosed slowly to an ethylene glycol solution at 120 C and reduced in the presence of a stabilizing polymer poly-N-vinylpyrollidone (PVP). Slow addition of the Pt-salt first will first lead to the formation of nuclei (seeds) which then grow further to produce larger particles of any desired size between 3 and 8nm. The amount of added hexachloroplatinic acid precursor controls the size of the final nanoparticle product. TEM was used to determine size and morphology and to confirm the crystalline nature of the nanoparticles. Good reproducibility of the technique was demonstrated. Above 7nm, the particle shape and morphology changes suddenly indicating a change in the deposition selectivity of the Pt-precursor from (100) towards (111) crystal faces and ...

Energy Technology Data Exchange (ETDEWEB)

A method to control charge transfer reaction in DNA using hybrid nanometer-sized TiO{sub 2} nanoparticles was developed. In this system extended charge separation reflects the sequence of DNA and was measured using metallic silver deposition or by photocurrent response. Light-induced extended charge separation in these systems was found to be dependent on the DNA-bridge length and sequence. The yield of photocatalytic deposition of silver was studied in systems having GG accepting sites imbedded in AT runs at varying distances from the TiO{sub 2} nanoparticle surface. Weak distance dependence of charge separation indicative of a hole hopping through mediating adenine (A) sites was found. The quantum yield of silver deposition in the system having a GG accepting site placed 8.5 {angstrom} from the nanoparticle surface was found to be {Phi} = 0.70 (70%) and {Phi} = 0.56 (56%) for (A){sub n} and (AT){sub n/2} bridge, ...

UK PubMed Central (United Kingdom)

BackgroundFor more than a decade there has been increasing interest in the use of nanotechnology and microarray platforms for diagnostic applications. In this report, we describe...Full Text Available

UK PubMed Central (United Kingdom)

RATIONALE AND OBJECTIVESNon-invasive longitudinal imaging of tumor vasculature could provide new insights into the development of solid tumors, facilitating efficient...Full Text Available

UK PubMed Central (United Kingdom)

Convection-enhanced drug delivery (CED) is a novel approach to delivering drugs into brain tissue. Drugs are delivered continuously via a catheter, enabling large volume distributions of high drug concentrations...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundPolyethyleneimine (PEI), which can interact with negatively charged DNA through electrostatic interaction to form nanocomplexes, has been widely attempted to use as a gene...Full Text Available

Science.gov (United States)

Selective removal of hexavalent chromium ions from aqueous solutions using a chitosan/gold nanoparticles composite film was demonstrated. Localized surface plasmon resonance (LSPR) was used to measure the interface stability and detect the incorporation of chromium ions over time. The effects of pH, ethylenediaminetetraacetic acid (EDTA), and various foreign ions such as trivalent chromium, sodium, calcium, phosphate, sulfate and chloride on the adsorption of hexavalent chromium were investigated. PMID:19381379

Energy Technology Data Exchange (ETDEWEB)

SnO{sub 2}-carbon nanotube (CNT) composite sheets are synthesized using poly(vinylpyrrolidone) to uniformly load a monolayer of SnO{sub 2} nanoparticles onto the surfaces of CNTs and CNT bundles within cross-stacked CNT sheets. When they are used as high-capacity (over 850 mA h g{sup -1}) and binder-free anodes in rechargeable lithium-ion batteries, they exhibit good cycle performance. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Energy Technology Data Exchange (ETDEWEB)

The novel optical, electronic, and/or magnetic properties of metal and semiconductor nanoparticles have resulted in extensive research on new methods for their preparation. An ideal preparation method would allow the particle size, size distribution, crystallinity, and particle shape to be easily controlled, and would be applicable to a wide variety of material systems. Numerous preparation methods have been reported, each with its inherent advantages and disadvantages; however, an ideal method has yet to emerge. The most widely applied methods for nanoparticle preparation include the sonochemical reduction of organometallic reagents,(1&2) the solvothermal method of Alivisatos,(3) reactions in microemulsions,(4-6) the polyol method (reduction by alcohols),(7-9) and the use of polymer and solgel materials as hosts.(10-13) In addition to these methods, there are a variety of methods that take advantage of the unique properties of a ...

Energy Technology Data Exchange (ETDEWEB)

A system for partial mechanisation of the support work with roadway driving machines consisting of a crawler undercarriage carrying a selective cutter with a cutting jib on a rotary tower is claimed. The system comprises a support manipulator movable in longitudinal direction over the rotary tower and cutting jib and a preassembly table with a number of brackets to take up and preassemble a support structure consisting of profile segments, preferably an arc-shaped support with a cap made up for several parts. The system is characterized in that the preassembly table is mounted on one side of the selective cutter and has one straight vertical guide bar each for at least two cap brackets which can be continuously adjusted in height, and in that the manipulator mounted on the selective cutter has a horizontally suivelling head which may grip under the cap of the preassembled structure on the preassembly table.

Energy Technology Data Exchange (ETDEWEB)

The composition of sputter-deposited HgS films was determined by electron microprobe analysis. From the relative x-ray intensity as a function of film thickness, the depth of the ionizations that produce SK sub(..cap alpha..) and HgM sub(..cap alpha..) was found to be approximately 0.65 ..mu..m at an accelerating voltage of 15 kV. This value agreed well with a value calculated from Castaings' empirical law after absorption correction. The determination of film composition was limited to sufficiently thicker films than this critical value, usually 1 - 2 ..mu..m thick. The relation between the conposition of bulk standard determined by chemical analysis and the x-ray intensity ratio was used for the correction of film composition. The results showed that the crystal structure of HgS films was independent of the composition, i.e., the growth of metastable ..beta..-HgS films was not caused by the nonstoichiometry, and that the composition ...

British Library Electronic Table of Contents (United Kingdom)

Novel fluoroalkyl end-capped vinyltrimethoxysilane oligomer/hydroxyapatite (HAp) nanocomposites were prepared by the reaction of calcium nitrate tetrahydrate and phosphoric acid in the presence of the corresponding oligomer. These fluorinated oligomer/HAp composites thus obtained are nanometer size-controlled fine particles (83-173 nm), and were found to exhibit good dispersibility in methanol, ethanol, and isopropyl alcohol. These fluorinated HAp nanocomposites were applied to the surface modification of glass and poly(methyl methacrylate) (PMMA) to exhibit good hydro- and oleophobic characteristics imparted by fluorine on their surface. In addition, the surface structural changes of the modified polyethylene terephtalate and PMMA films treated with these fluorinated nanocomposites before...

Energy Technology Data Exchange (ETDEWEB)

Single stage separation factors ..cap alpha.. have been determined for /sup 6/Li and /sup 7/Li between lithium ions in methanol and complexed ions with a cryptand (2 sub(B), 2, 1) polymer. The /sup 6/Li was concentrated in the cryptand. The separation factors were compared with the values of other chemical exchange systems. The maximum enrichment factor obtained was epsilon = 0.047 +- 0.002. The figure is one of the greatest in the chemical exchange reactions without valence change and almost 10 times larger than the values of ion exchangers. The variation in ..cap alpha.. depending on the chemical species was small in the non-aqueous system. High enrichment of lithium isotopes was expected to be achievable by means of the chromatographic application of the cryptand (2 sub(B), 2, 1).

Scientific Electronic Library Online (English)

Abstract in english Structural characterisations using the SAXS technique in a number of nanoheterogeneous materials and liquid solutions are reviewed. The studied systems are protein (lysozyme)/water solutions, colloidal ZnO particles/water sols, nanoporous NiO-based xerogels, hybrid organic-inorganic siloxane-PEG and PPG nanocomposites and PbTe semiconductor nanocrystals embedded in a glass matrix. These investigations also focus on the transformations of time-varying structures and on str (more) uctural changes related to variations in temperature and composition. The reviewed investigations aim at explaining the unusual and often interesting properties of nanostructured materials and solutions. Most of the reported studies were carried out using the SAXS beamline at the National Synchrotron Light Laboratory (LNLS), Campinas, Brazil.

Energy Technology Data Exchange (ETDEWEB)

This paper reports on the mathematical model developed by Sunu and Bennion that has been extended to include the separator, precipitation of both solid ZnO and K{sub 2}Zn(OH){sub 4}, and the air electrode, and has been used to investigate the behavior of a primary Zn-Air battery with respect to battery design features. Predictions obtained from the model indicate that anode material utilization is predominantly limited by depletion of the concentration of hydroxide ions. The effect of electrode thickness on anode material utilization is insignificant, whereas material loading per unit volume has a great effect on anode material utilization; a higher loading lowers both the anode material utilization and delivered capacity. Use of a thick separator will increase the anode material utilization, but may reduce the cell voltage.

Energy Technology Data Exchange (ETDEWEB)

A monolithic micromachined waveguide device or devices with low-loss, high-power handling, and near-optical frequency ranges is set forth. The waveguide and integrated devices are capable of transmitting near-optical frequencies due to optical-quality sidewall roughness. The device or devices are fabricated in parallel, may be mass produced using a LIGA manufacturing process, and may include a passive component such as a diplexer and/or an active capping layer capable of particularized signal processing of the waveforms propagated by the waveguide.

Wastenet

... The colored background is an isopleth map showing change in sulfate concentrations as measured by the CASTNET rural air quality monitoring network , leading to significant improvements in air quality and human health. Wet sulfate deposition decreased 43 percent in the Northeast and 44 percent in the ...

British Library Electronic Table of Contents (United Kingdom)

Interchangeable technology from Flexicon Liquid Filling, a business division of Watson-Marlow Pumps Group, has helped family-run diagnostic reagent manufacturer, Hart Biologicals Ltd, to accommodate business growth with the recent upgrade to a tabletop bottle filling and capping machine. A peristaltic dispensing pump is crucial for succes

International Nuclear Information System (INIS)

The thickness dependent magnetic properties of artificially prepared ultrathin body-centered cubic Ni films have been explored using the all electron full potential linearized augmented plane wave (FLAPW) method. We have considered two types of BCC Ni(001) films: (i) pure BCC Ni(001) and (ii) Au capped BCC Ni(001) in the range from 1 monolayer (ML) to 4 ML of Au capping coverage. The average magnetic moment of pure BCC Ni(001) is about 0.63 #mu#_B and a typical surface enhancement is found with a magnetic moment of 0.78 #mu#_B. In the presence of an Au capping layer, the magnetic moment of interface Ni is strongly suppressed to approximately 0.5 #mu#_B and this causes a reduction of average magnetic moment. Nevertheless, the Au adlayer has no meaningful induced magnetic moment. The BCC pure Ni(001) films always have in-plane magnetization up to 11 ML, but very interestingly the Au/Ni(001) shows a thickness dependent spin ...

Energy Technology Data Exchange (ETDEWEB)

The kinetic parameters, ..cap alpha.. the coupling coefficient and tau-bar the mean neutron transit time have been determined using a reactor oscillator on the coupled-core of the Queen Mary College research reactor. By using correlation techniques it has proved possible to use detectors small enough to be inserted in the fuel tanks. It is shown that the simplified Baldwin model with one-group diffusion theory is inadequate to describe the kinetic behaviour and the experimentally-determined parameters are dependent upon the positioning of the detectors.

Energy Technology Data Exchange (ETDEWEB)

Cathodic reduction of non-terminal vinylaxides on Hg cathodes in the presence of electrophiles gives reasonable yields of N-acylated enamines in an electrochemically totally irreversible reaction. In the presence of added H-donors rather high selectivity for formation of saturated amides is achieveable. The influence of reaction conditions on product distribution is discussed.

Energy Technology Data Exchange (ETDEWEB)

Mono-dispersed cubic CeO{sub 2} nanoparticles have been synthesized using a surfactant-assisted method with laurylamine hydrochloride and cerium alkoxide modified with acetylacetone in an aqueous solution system. The prepared cubic CeO{sub 2} nanoparticles had a highly crystallized structure at 353 K and formed rod-like structures by calcination at 673 K after freeze-drying the CeO{sub 2} gel. We discovered a clear potential to make 1D, 2D or 3D CeO{sub 2}-materials with a well-controlled characteristic length and shape by assembling cubic-shaped CeO{sub 2} nanoparticle building blocks. CeO{sub 2}-TiO{sub 2} composite nanostructures have also been synthesized by changing the mole ratio of cerium alkoxide/titanium alkoxides. By utilizing the redox characteristic of CeO{sub 2}, CeO{sub 2} nanoparticles and CeO{sub 2}-TiO{sub 2} composite nanostructures after calcination, showed reaction activity toward ...

International Nuclear Information System (INIS)

A systematic study for the materials design of III-V and II-VI compound-based ferromagnetic diluted magnetic semiconductors is given based on ab initio calculations within the local spin density approximation. The electronic structures of 3d-transition-metal-atom-doped GaN and Mn-doped InN, InP, InAs, InSb, GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs and AlSb were calculated by the Korringa-Kohn-Rostoker method combined with the coherent potential approximation. It is found that the ferromagnetic ground states are readily achievable in V-, Cr- or Mn-doped GaN without any additional carrier doping treatments, and that InN is the most promising candidate for high-T_C ferromagnet. A simple explanation of the systematic behavior of the magnetic states in III-V and II-VI compound-based diluted magnetic semiconductors is also given. It is also shown that V or Cr-doped ZnS, ZnSe, and ZnTe are ferromagnetic without p- or n-type doping treatment. However, Mn-, Fe-, Co- or Ni-doped ZnS, ZnSe and ZnTe ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

This paper presents a study on the crystallization and growth mechanism of selenium nanowires induced by silver nanoparticles at ambient conditions with special reference to the effects of factors such as the shapes and size of silver nanoparticles, the induced reaction time, and the molar ratio of Ag{sup 0} to SeO{sub 3}{sup 2-} ions. The synthesis approach is conducted with no need of any stabilizers, and with no sonochemical process and/or templates. It is found that whether silver spherical particles or colloids can lead to the formation of nanowires with average diameter of 25 nm and lengths up to a few micrometers, and silver nanoplates lead to the formation of flat Se nanostructures. In particular, Au, Cu, Pt, and Pd particles cannot induce the growth of selenium nanowires in aqueous solution at room temperature. The results indicate that silver particles play a critical role in determining the growth of selenium nanowires. The lattice ...

British Library Electronic Table of Contents (United Kingdom)

A novel method for the determination of metoclopramide (MCP) using electrogenerated chemiluminescence (ECL) is presented. A tris(2,2prime-bipyridyl)dichlororuthenium(II) (Ru(bpy)32+)-doped silica (RuDS) nanoparticle/perfluoinated ion-exchange resin (Nafion) with nanocomposite membrane modified glassy carbon electrode (GCE) is used. The Ru(bpy)32+ encapsulation interior of the silica nanoparticle maintains its electrochemical activities and also reduces Ru(bpy)32+ leaching from the silica matrix when immersed in water due to the electrostatic interaction. The analytical performance of this ECL sensor for MCP is shown in detail. Under optimal experimental conditions, it has good linearity in the concentration range from 2x10-8mol/L to 1x10-5mol/L (R=0.9989) with a detection limit of 7x10-9mo...

Science.gov (United States)

We report here a new approach to introduce the effect of chemisorption in the Monte-Carlo simulation procedure for studying the segregation behaviour in bimetallic nanoparticles at low pressures. A coordination-dependent pair interaction energy is constructed in terms of partial bond energies and the exchange energy where the partial bond energy can be empirically calculated from the experimental values of dimer energy, the pressure-dependent surface energy and the bulk cohesive energy of the constituent metals. The advantage of this procedure is the ability to estimate the pressure-dependent surface composition of the nanoparticles. The method has been applied to oxygen-adsorbed Pd-Ag systems; and it is found that while Ag segregate in clean particles, at higher oxygen pressures Pd atoms segregate to the surface. The present technique has been argued to be suitable for higher pressures (>10-5Torr) when coverage cannot be accurately ...

British Library Electronic Table of Contents (United Kingdom)

A stable BSA blocking poly(dimethylsiloxane) (PDMS) microchannel was prepared based on in situ synthesized PDMS-gold nanoparticles composite films. The modified microchip could successfully suppress protein adsorption. The assembly was followed by contact angle, charge-coupled device (CCD) imaging, electroosmotic flow (EOF) measurements and electrophoretic separation methods. Contact angle measurements revealed the coated surface was hydrophilic, water contact angle for coated chips was 45.2^o compared to a water contact angle for native PDMS chips of 88.5^o. The coated microchips exhibited reproducible and stable EOF behavior. With FITC-labeled myoglobin incubation in the coated channel, no fluorescence was observed with CCD image, and the protein exhibited good electrophoretic effect in ...

Energy Technology Data Exchange (ETDEWEB)

We report the simultaneous formation of self-assembled surface ripples in Cd{sub 2}Nb{sub 2}O{sub 7} pyrochlore caused by focused ion beam (FIB) patterning and uniformly distributed metallic nanodots induced by phase decomposition under ion bombardment. The characteristic wavelength of the surface ripples is controllable from the nm to the sub-{micro}m scale. High-density Cd metallic nanoparticles, {approx} 5 nm, formed and the distribution of nanoparticles is consistent with the morphological characteristics of the ripple pattern. This approach provides a means of fabricating surface nanostructure with various patterns and a controllable particle size and distribution by combining ion beam-induced phase decomposition with high-precision FIB patterning.

Energy Technology Data Exchange (ETDEWEB)

As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological information is needed to predict and optimize the film's electronic, optical and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector and synchrotron radiation in two simple geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomly-packed metallic nanoparticle films. This method can be immediately implemented to help understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.

Science.gov (United States)

The optical and nonlinear optical properties of colloidal solutions of silver obtained by laser ablation in water and ethanol are studied. It is shown that freshly prepared colloids experience a full or partial sedimentation by changing their nonlinear optical properties. Aqueous colloids undergo a partial sedimentation and their nonlinear optical absorption changes to nonlinear optical transmission. The obtained results are interpreted using the Drude model for metal particles taking the particle size into account and can be explained by the sedimentation of larger silver particles accompanied by the formation of a stable colloid containing silver nanoparticles with a tentatively silver oxide shell. The characteristic size of particles forming such a stable colloid is determined and its optical nonlinearity is estimated.

British Library Electronic Table of Contents (United Kingdom)

Abstract A highly efficient enzyme immobilization method has been developed for electrochemical biosensors using polydopamine films with gold nanoparticles (AuNPs) embedded. This simple enzyme fabrication method can be performed in very mild conditions and stored in a long time with high bioactivity. The fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, wide linear dynamic range and low limit of detection (LOD) (0.1 molL-1). A low value of 1.5 mmolL-1 for the apparent Michaelis-Menten constant KappM was obtained. The high sensitivity, wide linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.

British Library Electronic Table of Contents (United Kingdom)

Upconversion nanoparticles (UCNPs) with unique multi-photon excitation photoluminescence properties have recently been intensively explored as novel contrast agents for low-backgroundbiomedical imaging. In this work, we functionalize UCNPs with a polyethylene glycol (PEG) grafted amphiphilic polymer. The PEGylated UCNPs are loaded with a commonly used chemotherapy molecule, doxorubicin (DOX), by simple physical adsorption via a supramolecular chemistry approach for intracellular drug delivery. The loading and releasing of DOX from UCNPs are controlled by varying pH, with an increased drug dissociation rate in acidic environment, favorable for controlled drug release. Upconversion luminescence (UCL) imaging by a modified laser scanning confocal microscope reveals the time course of intracel...

British Library Electronic Table of Contents (United Kingdom)

Abstract Nanocomposites based on SnO2 with carbon scaffold were used as highly porous anode films on Ni substrates. The films were obtained by in situ deposition of the particles without any binder or excess carbon black avoiding any secondary treatment. Compared to similarly prepared uncoated SnO2 nanoparticles as well as conventionally prepared powder samples the capacity loss of the in situ deposited nanocomposite films is significantly reduced. Thus, this newly developed anode material combined with in situ film formation is a promising approach for high capacity anodes in Li-ion batteries. SEM-micrograph of a SnO2/C nanoparticle film.

British Library Electronic Table of Contents (United Kingdom)

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

British Library Electronic Table of Contents (United Kingdom)

In this work, silver-montmorillonite (Ag-MMT) antimicrobial nanoparticles have been obtained by allowing silver ions from nitrate solutions to replace the Na^+ of natural montmorillonite and then to be reduced by a thermal treatment. Ag-MMT were used as active antimicrobial compounds to improve the shelf life of fresh fruit salad. In order to assess their influence on product shelf life, sensorial and microbiological quality has been monitored during the storage. The microbiological quality was determined by monitoring the principal spoilage microorganisms (mesophilic and psychrotrophic bacteria, coliforms, lactic acid bacteria, yeasts and molds). Additionally, the evolution of sensorial quality was assessed by monitoring color, odor, firmness and product overall quality. The Ag-MMT nanopa...

Energy Technology Data Exchange (ETDEWEB)

A cooperative effort of the Center for Solar Energy and Hydrogen Research (ZSW) and Phototronics Solartechnik GmbH (PST) aimed at the transfer of highly efficient solar cells developed on a laboratory scale, to large-area thin-film solar modules suitable for production. This work was based on research and development at the Institute for Physical Electronics (IPE) of Stuttgart University and ZSW on one hand, and on the know-how of PST in regard to large-area module fabrication on the other hand. The various thin-film layers of the cells and modules comprize molybdenum as rear contact, copper-indium(gallium)-diselenide (CIGS) as absorber material, the combination of cadmium sulphide (CdS) and ZnO as window layer. To produce these layers on large areas (30x30 cm{sup 2}), equipment was constructed and procedures were developed. Monolithic series connection of cells, used in other thin-film technologies, was studied and optimized by suitable patterning procedures, such ...

Energy Technology Data Exchange (ETDEWEB)

In an aim to develop photo-responsive composites, the UV photo-reduction of aqueous titanium oxide nanoparticle-graphene oxide (TiO{sub 2}-GO) dispersions (Lambert et al. J Phys. Chem. 2010 113 (46), 19812-19823) was undertaken. Photo-reduction led to the formation of a black precipitate as well as a soluble portion, comprised of titanium oxide nanoparticle-reduced graphene oxide (TiO{sub 2}-RGO). When allowed to slowly evaporate, self assembled titanium oxide nanoparticle-graphene oxide (SA-TiO{sub 2}-RGO) films formed at the air-liquid interface of the solution. The thickness of SARGO-TiO{sub 2} films range from {approx}30-100 nm when deposited on substrates, and appear to be comprised of a mosaic assembly of graphene nanosheets and TiO{sub 2}, as observed by scanning electron microscopy. Raman spectroscopy and X-ray photoelectron spectroscopy indicate that the graphene oxide is only partially reduced in the SA-TiO{sub ...

UK PubMed Central (United Kingdom)

The synthesis of a new kind of magnetic, fluorescent multifunctional nanoparticles (~30 nm in diameter) was demonstrated, where multiple fluorescent CdTe quantum dots (QDs) are covalently linked...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Based on their interesting properties, metal nanoparticles show the potential as an analytical tool in electronic (Burmeister et al. 2004), optical (Yguerabide and Yguerabide 1998), and catalytic applications (Liu 2006). Their characteristics depend on the composition, shape, and size of the single particles. These various properties are utilized in many different approaches such as optics, magnetics (Lang et al. 2007), and laser technology (Csaki et al. 2007). We investigated an alternative method for the synthesis of nanoparticles. In this case, an enzyme, horseradish peroxidase, induces a silver deposition and replaces a metal nanoparticle as the reaction seed. Depending on the reaction time, we could obtain particles in a range of few nanometers up to more than 250 nm. For a better understanding of the enzymatic silver deposition process, the silver particles produced by this process were analyzed by SEM, TEM, and ...

International Nuclear Information System (INIS)

Based on theoretical calculations of powder diffraction data it is shown that the assumption of the infinite crystal lattice for small particles is not justified, leads to significant changes of the diffraction patterns, and may lead to erroneous interpretation of the experimental results. An alternate evaluation of diffraction data of nanoparticles, based on the so-called 'apparent lattice parameter', alp, is proposed. (author)

Energy Technology Data Exchange (ETDEWEB)

Preliminary results are presented from a field study to evaluate the relative hydrologic performance of various landfill capping technologies installed by the Los Alamos National Laboratory at Hill Air Force Base, Utah. Four cover designs (two Los Alamos capillary barrier designs, one modified EPA RCRA design, and one conventional design) were installed in large lysimeters instrumented to monitor the fate of natural precipitation between 01 January 1990 and 20 September 1993. After 45 months of study, results showed that the cover designs containing barrier layers were effective in reducing deep percolation as compared to a simple soil cap design. The RCRA cover, incorporating a clay hydraulic barrier, was the most effective of all cover designs in controlling percolation but was not 100% effective. Over 90% of all percolation and barrier lateral flow occurred during the months of February through May of each year, primarily as a result of snow ...

CERN Document Server

Extracting useful information from high-dimensional data is an important focus of today's statistical research and practice. Penalized loss function minimization has been shown to be effective for this task both theoretically and empirically. With the virtues of both regularization and sparsity, the $L_1$-penalized squared error minimization method Lasso has been popular in regression models and beyond. In this paper, we combine different norms including $L_1$ to form an intelligent penalty in order to add side information to the fitting of a regression or classification model to obtain reasonable estimates. Specifically, we introduce the Composite Absolute Penalties (CAP) family, which allows given grouping and hierarchical relationships between the predictors to be expressed. CAP penalties are built by defining groups and combining the properties of norm penalties at the across-group and within-group levels. Grouped selection occurs for ...

Science.gov (United States)

Continuous metallic glass ribbons were produced by mejans of liquid-quenching at rates >10/sup 50/C/s. The ribbons, typically 30 ..mu..m thick and 1 to 2 mm wide, were determined to be glassy by X-ray diffraction (XRD) employing CuK..cap alpha.. and MoK..cap alpha.. radiation. Mechanical properties of the as-quenched product were determined by measurements of hardness, tensile strength and Young's modulus. The Vicker's diamond pyramid microhardness (H/sub V/) was measured on epoxy mounted samples using a Lietz Miniload instrument with a 100 g load. Tensile tests were conducted in an Instron machine using specimens which were hand-polished to produce smooth, parallel sides. Young's modulus (E) is given by the relationship rho V/sub E/sup 2//. V/sub E/, the velocity of extensional mode waves, was measured by the pulse-echo technique using a Panametrics Intervalometer and glass density, rho, was obtained by the liquid ...

Energy Technology Data Exchange (ETDEWEB)

A set of computer codes have been developed to produce spectral line shapes of highly stripped ions for a number of transitions in Hydrogenic, Helium-like and Lithium-like species. The choice of the transitions has been dictated largely by the laser compression experiments. The transitions of Hydrogenic species are: Lyman ..cap alpha..; Lyman ..beta..; Lyman ..gamma..; Lyman delta; Balmer ..cap alpha..; and Balmer ..beta... The transitions of Helium-like species are: 1s/sup 2/(/sup 1/S/sub 0/)-1s2p(/sup 1/P); 1s/sup 2/(/sup 1/S/sub 0/)-1s3p(/sup 1/P); 1s/sup 2/(/sup 1/S/sub 0/)-1s4p(/sup 1/P) and the associated dipole-forbidden components. The transitions of Lithium-like species are the entire n = 2 to n = 3 and n = 4 complexes.

International Nuclear Information System (INIS)

During the operation of the Fast Flux Test Facility (FFTF), radioactive gases, primarily xenon and krypton, will be produced which will require processing and storing. Two systems have been installed in the FFTF for handling these gases: (1) one to handle, primarily, the reactor cover gas system, and (2) a second to handle the cells and cover gas systems, other than the reactor, whose atmosphere may become contaminated. The system that processes the reactor cover gas, which is argon, is called the Radioactive Argon Processing System (RAPS). The effluent argon from RAPS will normally be sufficiently decontaminated to allow its reuse as the reactor cover gas. If the radioactive level in the RAPS becomes too high, the exhaust stream will be diverted to the Cell Atmosphere Processing System (CAPS), a system which can function as a backup to RAPS. The design and operation of the RAPS and CAPS systems are described and certain safety aspects of the ...

Energy Technology Data Exchange (ETDEWEB)

We have measured the K-shell ionization probability Psub(K) across the isobaric analog resonances in the elastic channel of the reactions /sup 88/Sr(p, p/sub 0/)/sup 88/Sr at 5.06 MeV and /sup 86/Sr(p, p/sub 0/)/sup 86/Sr at 6.02 MeV. The dependence of Psub(K) on the beam energy for two scattering angles 90/sup 0/ and 155/sup 0/ is analysed in the framework of the theory developed by Anholt et al. taking into account the effect of compound-nucleus scattering. A compound elastic cross section (dsigma/d..cap omega..)sub(CE)=40+-10 mb/se at the peak of the resonance is deduced in the reaction /sup 88/Sr+p at 5.06 MeV, while the experimental results agree with a negligible value of (dsigma/d..cap omega..)sub(CE) for the resonance in /sup 86/Sr+p at 6.02 MeV.

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A method is proposed for the quantitative high-temperature isolation of /sup 111/In from silver irradiated by ..cap alpha..-particles into a gas phase containing a mixture of HCl and H/sub 2/O with a total pressure of about 3 Pa for these gases. It is shown that the indium evolved into the gas phase probably occurs in the form of at least three compounds, viz.., the trichloride, monochloride, and oxychloride, which have adsorption temperatures on quartz of around 385, 475, and 655 K, respectively. All these compounds are readily washed from the surface of quartz apparatus by a weak (0.05 M) solution of hydrochloric acid.

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This patent describes a process for preparing poly(aryl ether ketones) by nucleophilic displacement polymerization in the presence of at least one alkali metal base selected from potassium, rubidium or cesium, and fluoride ions, which comprises adding to the polymerization: (a) an effective amount of at least one metal salt selected from lithium, sodium, alkaline earth or lanthanide chloride, bromide, iodide, sulfate, alkyl or aryl carboxylate, cyanide, borate or phosphate to slow or stop advancement of molecular weight and (b) an end-capping agent.

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The US DOE is calling on the nations' industries and academic institutions to develop a new approach for converting coal into liquid fuels at costs that can be competitive with imported oil. Based on a number of innovations, the department is looking for new approaches that can substantially reduce the cost of liquids from coal, essentially capping the price of imported oil. If successful, the new process will define the next generation of coal liquefaction technology and represent a dramatic improvement over the current state-of-the-art integrated two-stage process. 1 fig.

International Nuclear Information System (INIS)

Transmissions of sperm by unirradiated and irradiated cotton bollworm, Helicoverpa armigera, were studied by live dissection of females immediately after the initiation of mating. In cotton bollworm the sperm transfer was rather a complex process. In fact unirradiated males failed to transfer sperm in about 19% of their matings. When irradiated with 250 Gy and 400 Gy, aberrations of sperm transmission were about 21% and 50% respectively. The failure of spermatophore 'cap' location was an important reason of sperm transmission aberrations. When females mated to high-dose-irradiated males, their oviposition response appeared abnormal

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The thermal desorption of stearic acid on superhydrophobic zinc oxide nanotowers has been investigated. The stearic acid passivated zinc oxide nanotowers provide a very high contact angle of {approx}173 {+-} 1.1 deg. with a very low hysteresis of {approx}1.4 {+-} 0.5 deg. due to the presence of a binary structure composed of several nanosteps on each nanotower of height {approx}700 nm that eventually reduces the area of contact between the drop and the nanotowers and trapping more air as revealed by the field emission scanning electron microscopy images. The superhydrophobic performance of these nanotowers, however, declines following annealing at elevated temperatures. Fourier transform infrared spectra show a reduction in the intensity of stearic acid -CH{sub n} peaks at elevated temperatures revealing the cause of the decrease in contact angle and confirming the occurrence of thermal desorption at 184 deg. C. The corresponding activation energy for desorption determined from our ...

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

International Nuclear Information System (INIS)

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

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Field corrosion tests were conducted on eight single tube materials and two welded overlay materials in three typical Japanese waste incineration plants in an effort to develop new corrosion-resistant superheater tubes capable of functioning efficiently under temperature and pressure conditions of 500 C and 100 kgf/cm{sup 2}-g in high-efficiency waste-to-energy (WTE) plants. Austenitic alloys containing higher concentrations of chromium, nickel, and molybdenum [Cr + Ni + Mo] showed excellent corrosion-resistant properties, and the new alloys JHN24 and HR30M showed good corrosion resistance. Different corrosion rates found in each of the three plants were explained by differences in operating conditions, such as gas temperature, concentration of molten salts resulting from chlorine (Cl) content of deposits, heavy metal (zinc oxide [ZnO] + lead oxide [PbO]) content, etc. It was confirmed that the corrosion rate of materials positioned in the first tube row facing 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 with 4.4 #OMEGA#/cm up to the annealing temperature as high as 850 deg. C without ...

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Results of an experimental study of the interaction of 140 MeV alpha particles with /sup 90/Zr nuclei resulting in fragmentation of the alpha particle are reported. The experimental observations of the study are analyzed and are found to show that alpha particle breakup reactions leading to at least 4-body final states, composed of two charged alpha particle fragments, contribute significantly to the singles yield of charged fragments observed at a fixed forward angle. The conclusions are based on coincidence measurements where one charged fragment is detected at a small forward angle which remains fixed, while the second charged fragment is detected at a series of coplanar secondary angles. The largest coincidence charged particle yield for the multiparticle final state events results from /sup 90/Zr(..cap alpha..,pp)X reactions, where both of the measured protons have energy distributions similar to the proton singles energy distributions. The second largest ...

International Nuclear Information System (INIS)

Superparamagnetic MFe23+O4 (M=Mn2+, Fe2+ and Co2+) inverse spinel ferrite (ISF) nanoparticles with narrow size distribution having average diameters of 6-8 nm were synthesized by a diol reduction of organic metals and the surface was modified to be hydrophilic by coating with succimer. Magnetic resonance imaging (MRI) contrast enhancement by dipolar coupling defined interactions between the synthesized ISFs and protons in the bulk water was investigated with initial susceptibility, magnetization and anisotropy of the succimer-coated ISFs. The relaxivity ratios, r2/r1, for MnFe2O4, Fe3O4 and CoFe2O4 were measured to be 12.2, 23.1 and 62.3, respectively, which demonstrate the potential usefulness of these magnetic nanoparticles as T2 contrast agents for MRI.

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Stearic acid gel is employed to study the phase evolution of MgTiO{sub 3} nanoparticles by thermal gravimetric analysis, X-ray diffraction, and Fourier transform infrared. During the preparation of stearic acid gel, tetrabutyl titanate easily absorbed moisture to hydrolyze into Ti(OH){sub 4} firstly, and then reacts with stearic acid and magnesium stearate to form magnesium-titanium oxide network polymer gel, meanwhile n-butanol is generated. When stearic acid gel is calcined in air, a series of oxidation and combustion reactions occur, meanwhile apparent heat is given off. The results show that a metastable intermediate phase Mg{sub 2}TiO{sub 4} is generated at 450 {sup o}C and nearly disappeared at 550 {sup o}C. Simultaneously, a new solid phase of MgTiO{sub 3} appears. The metastable intermediate phase Mg{sub 2}TiO{sub 4} is successfully identified in the current work.

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

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

The concept of nanocrystal conversion chemistry, which involves the use of pre-formed nanoparticles as templates for chemical transformation into derivative solids, has emerged as a powerful approach for designing the synthesis of complex nanocrystalline solids. The general strategy exploits established synthetic capabilities in simple nanocrystal systems and uses these nanocrystals as templates that help to define the composition, crystal structure, and morphology of product nanocrystals. This article highlights key examples of 'conversion chemistry' approaches to the synthesis of nanocrystalline solids using a variety of techniques, including galvanic replacement, diffusion, oxidation, and ion exchange. The discussion is organized according to classes of solids, highlighting the diverse target systems that are accessible using similar chemical concepts: metals, oxides, chalcogenides, phosphides, alloys, intermetallic compounds, sulfides, and nitrides. - Graphical ...

Science.gov (United States)

Macromolecular and polyanionic Na(+)-poly(gamma-glutamic acid) (PGA) silver nitrate complex acted as both a metal ion provider and a particle protector to fabricate nanosized silver colloids under chemical reduction by dextrose. The formation and size of particles have been characterized from transmission electron microscopy (TEM), dynamic light scattering analysis and UV-vis spectrophotometer. The results showed that the average particle size was 17.2+/-3.4 to 37.3+/-5.5 nm, apparently depending on the complex concentration. It was found that the rate constant and conversion of silver nanoparticles were proportional to the concentration of PGA. The growth mechanism of nanosized silver colloid was fully discussed. In addition, the in vitro cytotoxicity evaluated by L929 fibroblasts proliferation and antibacterial activity against Gram-positive strain (methicillin-resistant S. aureus (MRSA)) and Gram-negative strain (P. aeruginosa) bacteria have been assessed. ...

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

A novel composite film, comprising of hydrophobic ionic liquid (IL), multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (GNP), was fabricated and characterized. The GNP was introduced through electrochemical deposition on IL-MWNT gel film coated glassy carbon electrodes (GCE). Experiments showed that both IL and MWNTs could facilitate the GNP deposition. With GNP the composite film exhibited smaller electron transfer resistance and higher sensitivity in sensing guanine (G) and adenine (A). Under the optimized experimental conditions, the anodic peak currents were linear to the analyte concentration in the ranges of 0.008-2.0 ?M. The detection limits were down to nanomole level after an accumulation of 150 s on open-circuit. In addition, on the composite film coated GCE, the anodic peaks of G and A were well separated, and their response sensitivities kept almost unchanged no matter whether they coexisted or not. This proposed procedure was successfully ...

International Nuclear Information System (INIS)

Low pressure silane plasmas are known for their ability to synthesize silicon nanoparticles via gas phase nucleation. While in the past this particle formation has often been considered from the viewpoint of a contamination problem in semiconductor processing, we here describe a silane low pressure plasma that enables the synthesis of highly oriented, cubic-shaped silicon nanocrystals with a rather monodisperse size distribution. These silicon nanocubes have successfully been used in the manufacture of single nanoparticle vertical transistors. We discuss the advantages of this new paradigm of building nanoelectronic devices. The plasma synthesis process is characterized in more detail than in prior work. The particle nucleation, growth and shape evolution are studied. Results indicate that the process provides two spatially distinct zones: a diffuse plasma for particle growth and a constricted plasma zone for particle annealing. Measurements of ...

British Library Electronic Table of Contents (United Kingdom)

In this work, we report the preparation of lead titanate (PT) nanoceramics (with an average grain size of ~200nm in diameter) by using hydrothermal PT nanoparticles as start materials and characterized the dielectric and ferroelectric properties. The dielectric constant of the ceramic was found to be ~180 (at 1kHz) at room temperature and reached a maximum value of 8330 at ~490^oC, suggesting that the Curie temperature of the nanoceramics is consistent with the known value of PT crystals. Ferroelectric domains and hysteresis loops were obtained through piezoelectric force microscopy measurements, which provide direct and clear evidence for the ferroelectricity in the nanoceramic samples.

International Nuclear Information System (INIS)

The repulsive Casimir force is expected as a force which enables to levitate small objects such as machine parts used in Micro Electro Mechanical Systems (MEMS), and superlubricity in MEMS may be realized by this levitation. We study the Casimir force between a gold sphere and a nanocomposite sheet containing many nickel nanoparticles. In particular, we focus on the dependence of the Casimir force on the separation between the gold sphere and the surface of the nanocomposite sheet. The Casimir force changes from the attractive force to the repulsive force as the separation increases. The strength of the repulsive force is, however, too small to levitate MEMS parts.

Energy Technology Data Exchange (ETDEWEB)

In this study, liquid flame spray (LFS) was used to produce titania, silver and silver-titania deposits of nanoparticles. Titanium(IV)ethoxide (TEOT) and silver nitrate in ethanol solutions were used as precursors and sprayed into turbulent hydrogen-oxygen flame. Production rates of 1.5-40 mg/min of titania were used with silver additions of 1, 2, 4, and 8 wt% compared to titania. Nanoparticle deposits were collected by thermophoretic sampling at six different axial distances from the flame torch head: 3, 5, 10, 12, 15, and 20 cm, of which the all but the last one occurred inside the flame. The deposit samples were analysed by TEM and SAED analysis. The powder samples of the particles were also collected by electric precipitator to XPS and specific surface area analysis. Particle size and effective density after the flame in the aerosol were analysed with SMPS and ELPI. The results from the previous studies i.e. controlling the particle size by ...

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Nano-particles of CeO{sub 2} with the smallest average particle size (18.7 nm) and spherical morphology were obtained from a mixture solution of Ce(NO{sub 3}){sub 3}{center_dot}6H{sub 2}O, citric acid, polyvinyl alcohol by an auto-combustion process exploiting sol-gel as precursors. The course of size control and shape control by polyvinyl alcohol was examined in detail. A transmission electron microscopy (TEM) and an atomic force microscopy (AFM) were employed to characterize the particle-size and morphology of CeO{sub 2} particles. In addition, a sort of nano-metric solid acid SO{sub 4}{sup 2-}/CeO{sub 2} based on CeO{sub 2} nano-particles was prepared by macerating, filtering, drying and calcining processes. The particle-size of SO{sub 4}{sup 2-}/CeO{sub 2} was also assessed by TEM. The composition of SO{sub 4}{sup 2-}/CeO{sub 2} was analyzed by X-ray diffraction (XRD) and infrared spectra (IR). The influencing factors in the formation of ...