ytterbium doped fiber: Topics by WorldWideScience.org

Study of ytterbium doping effects on structural, mechanical and opto-thermal properties of sprayed ZnO thin films using the Boubaker Polynomials Expansion Scheme (BPES)

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 ...

2009-10-19

2

Nonstoichiometry of the Ytterbium Oxide

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

2009-10-19

3

Unitizations of double-ring structure and Erbium-doped waveguide amplifier for stable and tunable fiber laser

Full Text Available

1992-08-01

4

British Library Electronic Table of Contents (United Kingdom)

We propose and demonstrate experimentally a singlelongitudinal-mode (SLM) fiber double-ring laser using an Erbium-doped waveguide amplifier (EDWA), polarization controller (PC), and a fiber Fabry-Perot tunable filter (FFP-TF) into the ring cavity. In addition, the output power, side-mode suppression ratio (SMSR), and the stabilities of power and wavelength of the laser also are investigated. (Copyright 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

2007-01-01

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Tunable erbium-doped fiber ring laser for applications of infrared absorption spectroscopy

British Library Electronic Table of Contents (United Kingdom)

We fabricate a low noise erbium-doped fiber ring laser that can be continuously tuned over 102nm by insertion of the fiber Fabry-Perot tunable filter (FFP-TF) in the ring cavity with a novel cavity structure and the optimal gain medium length. As an application of this fiber ring laser, we performed the absorption spectroscopy of acetylene (13C2H2) and hydrogen cyanide (H13C14N) and measure the absorption spectra of more than 50 transition lines of these gases with an excellent signal to noise ratio (SNR). The pressure broadening coefficients of four acetylene transition lines are obtained using this fiber ring laser and an external cavity laser diode.

2007-01-01

6

Radiation hardening of optical fiber links by photobleaching with light of shorter wavelength

Responsive fibers from Modification of Acrylic Fibers

The influence of additionally injected short-wavelength photobleaching light on the radiation hardness of Ge-doped graded index fibers working at 1,300 nm wavelength is investigated. Predictions are complicated by the fact that more efficient shortwave bleaching light experiences higher radiation-induced loss. Promising results are found for low fiber temperatures (approx-lt -50 C) and bleaching light of about 835 nm wavelength.

1995-09-18

7

Spectroscopic characterization and temporal dynamics of energy transfer process between Tm{sup 3+} -Ho{sup 3+} and Yb{sup 3+} -Tm{sup 3+} ions in LiYF{sub 4} and LiLuF{sub 4} crystals; Caracterizacao espectroscopica e dinamica temporal dos processos de transferencia de energia entre os ions Tm{sup 3+} -Ho{sup 3+} e Yb{sup 3+} -Tm{sup 3+} em cristais de LiYF{sub 4} and LiLuF{sub 4}

Full Text Available

2004-02-01

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A study of neutron transmutation doped germanium

In this work, we perform spectroscopic studies to characterize the energy transfer processes occurring in rare-earth doped lithium fluoride systems, aiming the optimization of the population inversion of these media. Yb{sup 3+} ion was used in order to probe the electron-phonon coupling in LiYF{sub 4}, LiGdF{sub 4} and LiLuF{sub 4} matrices. In these systems it was obtained the average phononenergy, the vibronic transition probability and Huang-Rhys coupling constant. These parameters are dependent on the crystal host and the LiLuF{sub 4} system presents excluded correlation effects, an electronic repulsion that weakens the vibronic coupling. The Tm:Ho:LiYF{sub 4} system was studied under diode laser pumping at 796 nm, aiming the 2 {mu}m emission optimization. The ideal conditions of concentration and laser power were determined favouring the latter emission. Upconversion processes of two photons were identified besides the energy transfer among ions. The dynamic ...

2001-07-01

9

Quartz fibers a new calorimetry for multi-TeV, very forward physics

No abstract prepared

1998-01-01

10

Fiber Reinforced Superalloys - NASA Technical Reports Server

Quartz fibers

1995-01-01

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:z:..... \\ - NASA Technical Report Server (NTRS)

hlgh fiber content composites met the minlmum requirements. (1400 O F ) , the hlgher fiber content as-fabricated composites have impact strengths distinctly ...

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Monte Carlo characterization of an ytterbium-169 high dose rate brachytherapy source with analysis of statistical uncertainty

A common reinforced liner material is a cloth formed of PTFE fibers and fiber of ... and ablation protection provided. All of these methods of thermal ..... The influence of fiber content on the microstructures of the composites is ...

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Growth of ytterbium tartrate trihydrate crystals in silica and agar-agar gels and their characterization

An ytterbium-169 high dose rate brachytherapy source, distinguished by an intensity-weighted average photon energy of 92.7 keV and a 32.015#+-#0.009 day half-life, is characterized in terms of the updated AAPM Task Group Report No. 43 specifications using the MCNP5 Monte Carlo computer code. In accordance with these specifications, the investigation included Monte Carlo simulations both in water and air with the in-air photon spectrum filtered to remove low-energy photons below 10 keV. TG-43 dosimetric data including S_K, D(r,#theta#), #LAMBDA#, g_L(r), F(r,#theta#), #phi#_a_n(r), and #phi#_a_n were calculated and statistical uncertainties in these parameters were derived and calculated in the appendix.

2006-01-01

14

British Library Electronic Table of Contents (United Kingdom)

Single crystals of ytterbium tartrate trihydrate have been grown by gel method using silica and agar-agar gels as media of growth. The medium of growth influences the morphology of grown crystals, silica gel yielding single and polycrystalline in the form of spherulites whereas agar-agar gel leading to growth of single and twinned crystals. Materials grown as single crystals have been characterized by using optical and scanning electron microscopy (SEM), EDAX, XRD, FT-IR, CHN and thermogravimetric techniques. The stoichiometry of the grown single crystals is suggested to be Yb(C4H4O6) (C4H5O6).3H2O. The FT-IR spectrum shows the presence of singly as well as doubly ionized tartrate ligands. Results of thermal analysis indicate that the material is thermally stable up to a temperature of 200...

2006-01-01

15

Electric and magnetic properties of Yb-(Pt, Pd)-(GeSi) intermetallides

Dielectric and thermal characteristics of gel grown single crystals of ytterbium tartrate trihydrate

New ternary compounds on the ytterbium base YbPd_2Ge, YbPd_2Si, YbPdGe, YbPdSi, YbPtGe, YbPd_2Ge_2 and known compound YbPdSi_2 were obtained and investigated. Results of measuring the electric resistivity and magnetic susceptibility in the 4.2-300 K range are presented. It is found that YbPdGe, YbPtGe, YbPd_2Ge at low temperatures have magnetic phase transitions, investigations of which testify to dominant contribution of ferromagnetic ordering. The investigation results testify also to substantial effect of ytterbium crystalline environment on the physical properties of compounds under study.

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British Library Electronic Table of Contents (United Kingdom)

Dielectric and thermal characteristics of gel grown single crystals of ytterbium tartrate trihydrate have been carried out. The dielectric constant has been measured as a function of frequency in the range 2?kHz?1?MHz and temperature range 30?300??C. The dielectric constant increases with temperature, attains a peak near 215??C, and then decreases as the temperature exceeds 215??C. The dielectric anomaly at 215??C is suggested to be due to phase transition brought about in the material. The dielectric behaviour of the material is correlated with the results on thermal analysis. Thermogravimetric and differential thermal analysis have been used to study the thermal characteristics of the material. The experimental results show that the material is thermally stable up to 200??C. The decompos...

2007-01-01

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Rare-earth doped (#alpha#'/#beta#')-sialon ceramics

Rare Earth Doped Yttrium Aluminum Garnet (YAG ... - GLTRS - NASA

The objectives of this research were to investigate the possibility of controlling the #alpha#'/#beta#' phase ratio and morphology in Sialon ceramics. These objectives have been sought by the control of the starting composition, and by post sintering heat treatment. The main emphasis has been on the production of a series of #alpha#' and (#alpha#'+#beta#') Sialon ceramics with a minimum amount of the glass phase by the pressureless sintering technique and using ytterbium (Yb) as an #alpha#' stabilising element. The Yb additions were made via the oxide or the alumino- silicate presynthesised glass; the latter was found to improve the density. The XRD analysis of the as sintered materials revealed #alpha#' to be the dominant phase with minor contributions from #beta#' sialon and/ or 12H A1N polytype. Additions of SiO_2 or #beta#-Si_3N_4 were made to various materials to assess potential mechanisms for obtaining control over the microstructural development of ...

18

Properties of Reduced Polyacrylonitrile Nano Fiber (I)

films and cylinders of rare earth doped yttrium aluminum garnets. ... We knew that yttrium aluminum garnet (YAG) could be doped with ...

19

Mechanical Properties of Coir/Glass Fiber Phenolic Resin Based Composites

Full Text Available

2006-04-01

20

Compressive and Flexural Properties of Hemp Fiber Reinforced Concrete

Not Available

2008-09-01

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Preparation of flame resistant fibers from polyacrylonitrile fibers

Full Text Available

2004-09-01

22

Fibrillation of Commercial Acrylic Fiber for Use in Combustible Cartridge Cases.

In this article, a continuous stabilization process was used to make flame resistant fibers from polyacrylonitrile (PAN) fibers. The effect of the stabilization time and the stretching process during the stabilization process on the physical properties and flammability of the resultant flame resistant fibers was studied. Increased drawing of PAN fibers during the continuous stabilization process was found to decrease the diameter and increase the tensile strength in the resultant flame resistant fibers. These fibers also had higher density. There were no absolute relationships seen between flame-resistance and the formation of stable ladder polymers, density, and oxygen content. ((orig.))

1994-07-27

23

Biomimetic metal-sorbing vesicles for continuous extraction of heavy metal ions from dilute solution

A production method was developed to fibrillate commercial acrylic fiber suitable for the manufacture of combustible cartridge cases.

1983-01-01

24

Effect of fiber treatments on tensile and thermal properties of starch/ethylene vinyl alcohol copolymers/coir biocomposites.

Biomimetic vesicle media which can selectivity extract and concentrate heavy metals (e.g., Pb{sup 2+}) from dilute solutions of 5 ppm and less have been prepared. At a concentration of only 1% 2/v, these non-covalently assembled, unilamellar, surfactant vesicles provide approximately 1,000m{sup 2} of exposed membrane surface area per liter of suspension which gives rise to very rapid rates of metal ion extraction. To facilitate the selective transport of heavy metal ions through the ion impermeable vesicle wall, the vesicles are doped with lipophilic ionophores, both natural and synthetic. In addition, the metal chelating agent, nitrolotriacetate, is encapsulated in the aqueous vesicle core to provide the driving force for metal ion uptake and concentration. Concentration factors in excess of 1000 fold have been observed. Metal-sorbing surfactant vesicles measuring approximately 100 nm in diameter are stable and have been tested in a bench-scale metal ion ...

1993-12-31

25

Tin doping in spray pyrolysed indium sulfide thin films for solar cell applications

Coir fibers received three treatments, namely washing with water, alkali treatment (mercerization) and bleaching. Treated fibers were incorporated in starch/ethylene vinyl alcohol copolymers (EVOH) blends. Mechanical and thermal properties of starch/EVOH/coir biocomposites were evaluated. Fiber morphology and the fiber/matrix interface were further characterized by scanning electron microscopy (SEM). All treatments produced surface modifications and improved the thermal stability of the fibers and consequently of the composites. The best results were obtained for mercerized fibers where the tensile strength was increased by about 53% as compared to the composites with untreated fibers, and about 33.3% as compared to the composites without fibers. The mercerization improved fiber-matrix adhesion, ...

2009-06-26

26

British Library Electronic Table of Contents (United Kingdom)

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

2010-01-01

27

Structure and properties of high-performance polymeric and carbon fibers - an overview

Wear resistant composite structure of vitreous carbon containing convoluted fibers. Quarterly report No. 4

In this paper structure and mechanical properties of PBZT and PBO fibers are briefly discussed. One limitation of the high-modulus polymeric fibers and ultrahigh-modulus carbon fibers in reinforced composites is their poor compressive strength. Issues related to the compressive strength of polymeric and carbon fibers are considered. 62 references, 7 figures, 4 tables.

1989-01-01

28

Optical Diffraction Studies of Muscle Fibers

This report presents a brief description of the fabrication and advantages of a composite, carbon-metal fiber material which does not require lubrication.

1995-05-01

29

Influence of Fiber Loading on Thermal Ablation of PTFE,

A new technique to monitor light diffraction patterns electrically is applied to frog semitendinosus muscle fibers at various levels of stretch. The intensity of the diffraction lines, sarcomere length...Full Text Available

1973-09-01

30

Effect of the Fiber Size on the Physicochemical and Mechanical Properties of Composites of Epoxy and Date Palm Tree Fibers

... Accession Number : ADD431225. Title : Influence of Fiber Loading on Thermal Ablation of PTFE,. Corporate Author : Personal Author(s) : Letson,KN. ...

1979-07-16

31

British Library Electronic Table of Contents (United Kingdom)

Lignocellulosic fibers from date palm trees were employed to reinforce an epoxy matrix. Two fiber sizes were used, with the length and diameter in the range of 20-30 and 1.5-3 mm, respectively, for the so-called long fibers, and in the range of 5-15 and 0.25-0.75 mm, respectively, for the so-called short fibers. The morphologies of the resulting composites, as well as their thermal, mechanical, and water sorption properties were evaluated. Strong interactions between both components and etherification reactions may occur between the hydroxyl groups of the fibers and the epoxy groups of the epoxy-amine reactive mixture. These effects are emphasized when decreasing the size of the fibers.

2008-01-01

32

Cooperative Charging Effects of Fibers From Electrospinning ...

An Optical Fiber Infrasound Sensor

... In the Proceedings of INTC 2003, we studied charging effects on target coverage during electrospinning (16). ... of Fibers from Electrospinning of ...

2005-01-05

33

Stabilisation of #alpha#-Sialons using multiple additives

... We use a compliant, sealed tube helically wrapped with an optical fiber. ... 2.5 cm diameter compliant, sealed tube 10 m < length < 120 m ...

2000-09-01

34

Multi-cation #alpha#-Sialon ceramics were prepared using mixtures of samarium with calcium, magnesium, yttrium and ytterbium, and compared with a pure Sm-Sialon of equivalent total stabilising cation composition. A ratio of 80eq% samarium to 20eq% of the second stabilising additive was used. Samples were fired at 1820 deg C and subsequently heat treated at 1450 deg C. XRD phase analysis showed that all additives resulted in greater #alpha#-Sialon stability, and that calcium was the most effective additive for the stabilisation of the #alpha#-Sialon phase. Copyright (1998) Australasian Ceramic Society

1998-09-28

35

Phase diagrams

Pullout behavior of steel fibers from cement-based composites

The description is presented of binary phase diagrams of titanium alloyed with the following elements: silver, aluminium, arsenic, gold, boron, barium, beryllium, bismuth, carbon, calcium, cadmium, cobalt, chromium, copper, iron, gallium, germanium, hydrogen, hafnium, indium, iridium, potassium, lithium, magnesium, manganese, molybdenum, nitrogen, sodium, niobium, nickel, oxygen, osmium, phosphorus, lead, palladium, platinum, plutonium, rhenium, lanthanium, cerium, preseodymium, neodymium, gadolinium, erbium, terbium, thulium, lutetium, rhodium, ruthenium, scandium, silicon, tin, strontium, tantalum, technetium, thorium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc and zirconium.

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Fundamental study on evaluation method for alkali-resistance of fibers. Kakushu sen'i no tai arukarisei no hyokaho ni kansuru kiso kenkyu

A comprehensive experimental program on pullout tests of steel fibers from cement based matrices is described. A specially designed single fiber pullout apparatus was used to provide a quantitative determination of interfacial properties that are relevant to toughening brittle materials through fiber reinforcement. The parameters investigated included a specially designed high strength cement based matrix called Densified Small Particles system (DSP), a conventional mortar matrix, fiber embedment length, and the fiber volume fraction. The mediums from which the fiber was pulled included a control mortar mix without fibers, a mortar mix with 3, and 6 percent fibers by volume. The results indicate that: (1) the dense DSP matrix has significantly improved interfacial properties as compared to the conventional mortar matrix. ...

1997-06-01

37

Structure and Mechanical Properties of Boron-Doped Cubic ...

In order to clarify the alkali-resistance of fibers to be utilized as reinforcing materials for concrete, such as glass fiber, Aramid fiber, and carbon fiber, accelerated aging tests in alkaline solution were conducted. In detail, the degree of degradation of the fracture strength and Young's modulus were investigated through static tensile strength tests after soaking in alkaline solution of these fibers and then the mechanism of degradation was examined by observation using a scanning electron microscope. The conclusion obtained was as follows. Glass fiber was easily degraded in the alkaline solution and the progress of degradation was simulated quantitatively by the method proposed in this paper, which was based on a diffusion theory. Both Aramid fiber and carbon fiber showed a significant alkali-resistance ...

1994-05-20

38

The analysis of the influence of fiber length distribution on the theoretical and additional unevenness of yarn

... by the boron doping in most of the alloys except for Al66Mn9Zr25 + 50 ppm B alloy; permanent deformation at ultimate compressive strength is not ...

39

TEMPERATURE-DEPENDENT DIELECTRIC MEASUREMENTS OF POLYACRYLONITRILE FIBERS DURING AIR OXIDATION (Paper)

Full Text Available

40

Studies on a Novel Polyacrylonitrile Copolymer/Cellulose Acetate Blending Water Absorbency Fiber

No abstract prepared.

2004-01-26

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

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Some Consideration on Structure of Carbon fibers during Hot Stretching

Full Text Available

2010-09-01

42

Retinal Nerve Fiber Layer Thickness Analysis in Early Glaucoma

Full Text Available

1999-01-01

43

Preparation of Activated Carbon Fiber-Ceramic Composites and Its Physical Properties

Full Text Available

2008-07-01

44

Optical Fiber Sensors from Laboratory to Field Trials: Applications and Trends at CEA LIST

Full Text Available

1997-01-01

45

British Library Electronic Table of Contents (United Kingdom)

Fiber optic metrology developed at the CEA LIST laboratories involves fiber Bragg grating sensors, distributed Brillouin optical time domain reflectometry and optically stimulated luminescence dosimetry. Recent activities in optical fiber sensing are reviewed from laboratory experiments to field trials.

2009-01-01

46

Optic nerve head topographic measurements and retinal nerve fiber layer thickness in physiologic large cups.

Morphological Behavior of Oxy-PAN Fiber upon pH Variation

Full Text Available

2005-09-01

47

Microstructure and mechanical properties of apocynum venetum fibers extracted by alkali-assisted ultrasound with different frequencies

Full Text Available

2002-07-01

48

Mechanical Properties of Polypropylene Composites Reinforced with Chemically Treated Coir and Abaca Fiber

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49

Influences of Organic-modified Fe-montmorillonite on Structure, Morphology and Properties of Polyacrylonitrile Nanocomposite Fibers

Not Available

2009-10-01

50

Impact Resistance Evaluation of RC Beams Strengthened with Carbon FRP Sheet and Steel Fiber

Full Text Available

2009-12-01

51

Hydrolysis of Olive Oil Catalyzed by Surfactant-Coated Candida rugosa Lipase in a Hollow Fiber Membrane Reactor

Full Text Available

2010-10-01

52

Genome-wide analysis reveals rapid and dynamic changes in miRNA and siRNA sequence and expression during ovule and fiber development in allotetraploid cotton (Gossypium hirsutum L.)

Full Text Available

2007-04-01

53

BackgroundCotton fiber development undergoes rapid and dynamic changes in a single cell type, from fiber initiation, elongation, primary and secondary wall biosynthesis, to fiber...Full Text Available

2009-01-01

54

Fibrous Carbon

Fiber optic infrared thermometer for accurate measurement of the core temperature of the human body

... was noted. It was reported that similar fibers also grew on particles of thermal carbon black at a temperature of 10500 and in an atmosphere ...

1963-05-10

55

Electrospun Nanocomposite Fiber Mats of Zinc-Oxide Loaded Polyacrylonitrile

Not Available

2001-06-01

56

Effects of positive and negative stretching on the structure and properties of polyacrylonitrile fibers in the pre-oxidation process

Full Text Available

2008-06-01

57

Effects of Polymerization and Spinning Conditions on Mechanical Properties of PAN Precursor Fibers

Full Text Available

2011-06-01

58

Dyeability and Functionality of Pine Needles Extract (Part II) -Dyeing Properties of Protein Fiber-

Full Text Available

2010-09-01

59

Development of a fiber coupled, end pumped, Nd:YAG laser spark plug

Full Text Available

2011-04-01

60

Development and Fabrication of Compositions for 155-mm ...

None provided

2007-09-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

61

Depositon of ZnO on polyacrylonitrile fiber by thermal solvent coating

... Descriptors : *PROPELLING CHARGES, *NITROCELLULOSE, *COMBUSTIBLE CARTRIDGE CASES, DENSITY, FIBERS, MANUFACTURING ...

1982-10-01

62

Behavior of fiber reinforcements and resin flow during the injection-pultrusion process

Full Text Available

63

Behavior of abrasive wear on counterpart roughness of glass fiber reinforcement polyurethane resin composites

The purpose of the work described in this dissertation is to increase the understanding of injection-pultrusion process. Three major substudies related to injection-pultrusion have been completed: measurement of the compressibility of fiber reinforcements, measurement of in-plane and transverse resin flow through fiber reinforcements, and development of a resin flow model. This dissertation also presents results of an experimental and analytical investigation of in-plane and transverse resin flow through fiber reinforcements.

1990-01-01

64

Antibacterial Activity of Activated Carbon Fibers Containing Copper Metal

Full Text Available

2011-08-01

65

A Study on the Mechanical Properties of Recycled Aggregate Concrete Mixed Steel Fiber

Full Text Available

2003-05-01

66

A Study on Fiber Formation and Physical Properties of Polyacrylonitrile Copolymer with Itaconic acid

Full Text Available

2009-08-01

67

Mechanical behavior of self-assembled carbon nanotube reinforced nylon 6,6 fibers

Full Text Available

2002-04-01

68

British Library Electronic Table of Contents (United Kingdom)

The versatile electrospinning technique was used to successfully align and disperse multiwalled carbon nanotubes (MWCNT) in nylon 6,6 matrix to obtain composite fibers. The morphology of the composite fibers and the dispersion of the CNTs within the fibers were analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. TEM analysis revealed that the CNTs were well-dispersed, separated and aligned along the fiber axis. The thermal and mechanical properties of the composite fibers were characterized as a function of weight fraction of the CNTs. Incorporation of the CNTs in the fibers resulted in an increase in glass-transition temperature (Tg) by 7degreeC, indicating that the addition of CNTs has restricted the mobility of the polymer chains a...

2010-01-01

69

Interfacial characteristics of wood fiber/polystyrene composites

Effect of matrix strength on pullout behavior of steel fiber reinforced very-high strength concrete composites

Considerable interest has focused recently on the use of lignocellulosic fibers as a reinforcement for thermoplastic polymers. The combination of these dissimilar materials, however, is characterized by a widespread incompatibility that leads to a weak fiber/polymer interface and poor performance properties for the composite. In an effort to improve compatibility a number of fiber surface modification approaches have been investigated including plasma, ozone, and polymer grafting treatments. Evaluation of adhesion improvements has been complicated by processing variables that are difficult to control. This paper will discuss the use of the-micro-debond test in quantifying the interfacial shear strength (ISS) in wood fiber/polystyrene composites. Wood fibers were modified to different degrees with styrene-maleic anhydride copolymers that varied in their composition. The effect of ...

1995-12-01

70

British Library Electronic Table of Contents (United Kingdom)

This paper presents the results of single-fiber pullout tests for deformed and smooth steel fibers embedded in the newly developed very-high strength concrete (VHSC) matrixes. The pullout test program involved four types of steel fibers, eight compressive strengths of VHSC matrixes, and two normal concrete strengths. Test results have shown that pullout behavior of different steel fiber reinforced VHSC composites is influenced by the matrix strength and fiber end condition (smooth, flat end, or hooked). Results reveal that both maximum pull-out load and total pullout energy increases as matrix strength increases for all deformed fibers that did not rupture. The test results also indicated that the increase in total pullout energy is more significant than that in peak load.

2011-01-01

71

Cellulose and cellulignin from sugarcane bagasse reinforced polypropylene composites: Effect of acetylation on mechanical and thermal properties

British Library Electronic Table of Contents (United Kingdom)

This current work is concerned with the development of polypropylene composites reinforced with cellulose and cellulignin fibers attained from sugarcane bagasse. Moreover, the fibers were chemically modified by acetylating process and its effects on the fiber/matrix interaction were also evaluated. The chemical modification efficiency was verified by FTIR analysis and the fibers morphological aspects of fibers by SEM. Likewise, the influence of modified fibers content in the composites was studied by mechanical (tensile, shear and flexural tests) and thermal analyses (TGA and DSC). After the chemical modification, the FTIR results showed the appearance of acetyl groups and reduction of OH bonds for all fibers. Together with, SEM characterization showed that the acetylation changed the morp...

2008-01-01

72

An experimental study on the tensile strength of steel fiber reinforced concrete

British Library Electronic Table of Contents (United Kingdom)

This paper deals with steel fiber reinforced concrete mechanical static behaviour and with its classification with respect to fibers content and mix-design variations. A number of experimental tests were conducted to investigate uniaxial compressive strength and tensile strength. Different mixtures were prepared varying both mix-design and fiber length. Fibers content in volume was of 1% and 2%. Mechanical characterization was performed by means of uniaxial compression tests with the aim of deriving the ultimate compressive strength of fiber concrete. Four-point bending tests on notched specimens were carried out to derive the first crack strength and the ductility indexes. The tensile strength of steel fiber reinforced concrete (SFRC) was obtained both from an experimental procedure and b...

2010-01-01

73

Morphology and thermal properties of electrospun fatty acids/polyethylene terephthalate composite fibers as novel form-stable phase change materials

Fiber optic quality assurance at the Nevada Test Site

The ultrafine fibers based on the composites of polyethylene terephthalate (PET) and a series of fatty acids, lauric acid (LA), myristic acid (MA), palmitic acid (PA), and stearic acid (SA), were prepared successfully via electrospinning as form-stable phase change materials (PCMs). The morphology and thermal properties of the composite fibers were studied by field emission scanning electron microscopy (FE-SEM) and differential scanning calorimetry (DSC), respectively. It was found that the average fiber diameter increased generally with the content of fatty acid (LA) in the LA/PET composite fibers. The fibers with the low mass ratio maintained cylindrical shape with smooth surface while the quality became worse when the mass ratio is too high (more than 100/100). Moreover, the latent heat of the composite fibers increased with the increase of LA content and the ...

2008-11-15

74

Fiber optic feedthrough module and method of making same

A large number of fiber optic cables were used in support of a neutron imaging experiment at the Nevada Test Site. This paper describes the quality control testing of fiber components used on this experiment. The principal reason for quality control testing was to ensure reliable, high transmission fibers; a secondary reason was to gain data on a large sample of fiber cables in the field. Also described is the instrumentation developed for carrying out these field measurements. The design of the quality control instrumentation was a compromise between accuracy and simplicity of use.

1981-01-01

75

Crossing Zones in the Vestibulocerebellum: A Commentary

A fiber optic feedthrough module which comprises a metal sleeve, a fiber optic element extending through the sleeve in spaced relation thereto, and a tandem series of centrally-apertured mating annular sealant bodies of thermoplastic material surrounding the fiber optic element and compressed between it and the sleeve. The module is made by first providing a loose subassembly of a plurality of individual but interfitting sealant bodies on the fiber optic element and then inserting this subassembly into a metal sleeve, following by swaging the whole assembly which eliminates clearances and provides sealed interfaces between the various contacting components. (author).

1983-05-25

76

British Library Electronic Table of Contents (United Kingdom)

The contention of this commentary, focused on the vestibulocerebellum (particularly the flocculus), is that the great importance for our understanding of cerebellar organization in terms of climbing fiber zones, begun years ago by Voogd [1969, 2011] and Oscarsson [1969], needs to be matched by coming more to grips with the other fundamental geometrical organization of the cerebellum, the parallel fibers. The central issue is the selection of those parallel fiber signals to be transformed into Purkinje cell activity in the different zones. At present, in comparison to our knowledge of vestibulocerebellar climbing fiber inputs, the deficiencies in our knowledge of the zonal anatomy and physiology of vestibulocerebellar mossy fibers and granule cells are glaring. The recent emphasis on molecu...

2011-01-01

77

Ultraviolet dosimetry characterization from calcium doped borate glass-ceramic

Studies in crystal structure and luminescence properties of Eu3+-doped metal tungstate phosphors for white LEDs

No abstract prepared.

2006-07-01

78

Preparation, characterization and photocatalytic activity of the neodymium-doped TiO2 hollow spheres

Not Available

2011-12-01

79

Influence of germanium and oxygen impurities on the radiation hardening of monocrystalline silicon

Not Available

2010-10-01

80

Electrical properties of S implanted GaAs annealed by covering with As doped a-Si:H films

... defects doped materials germanium infrared radiation monocrystals neutron

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81

Influence of Dopants on Characteristics of X-Ray Detectors Fabricated from Indium-, Gallium-, and Chlorine-Doped Cadmium Telluride Single Crystals

Short communication.

1995-12-31

82

Electron beam processing of rubber wood fibers - polypropylene composites. Effects of reactive additives on the physical and mechanical properties

Counting characteristics of X-ray detectors fabricated from indium-doped, gallium-doped, and chlorine-doped CdTe have been investigated. The detectors fabricated from indium-doped and gallium-doped crystals showed radiation-induced polarization, namely, a progressive decrease of count rate with an increase of photon fluence in the high-photon-fluence region, while the detectors fabricated from chlorine-doped crystals did not. Results from current-voltage characteristics of the detectors indicated that the different counting characteristics of these detectors originated from the difference in internal electric fields in each detector.

1995-08-01

83

TUNABLE FIBER FABRY-PEROT FILTER FOR OPTICAL CARRIER-SUPPRESSION AND SINGLE-SIDEBAND MODULATION IN RADIO OVER FIBER LINKS

The purpose of this study is to determine the suitability of producing agro-fiber reinforced plastic composite (agro-FRPC) from rubber wood fiber blended in polypropylene matrix. The effects of varying fiber dimension and fiber content on the physical and mechanical properties of the composite were evaluated to provide an insight into the fiber matrix adhesion. The effects of reactive additives on the physical and mechanical properties of the composite were evaluated which provides the insight on the reinforcement of the composite. Rubber wood fiber used in this study is currently being used in the manufacturing of medium density fiber (MDF) board. Two sizes of rubber wood fiber were used i.e. 0.5-1.0 mm and 1.0-2.0 mm. Homopolymer polypropylene of MFI 14.0 was used as a matrix. The irradiation work was carried out using ...

2000-03-13

84

British Library Electronic Table of Contents (United Kingdom)

A novel method of simultaneous realization of optical carrier-suppression and single-sideband modulation using fiber Fabry-Perot tunable filter is presented. In order to enhance transmission performance of radio over fiber links, we use a fiber Fabry-Perot tunable filter to filter out one sideband as well as suppress the optical carrier power. The results demonstrate 20.5dB and 14.2dB improvement in the signal noise ratios when 18GHz and 10GHz microwave signals carrying 5Mbit/s quadrature-phase-shift-keyed (QPSK) format data is transmitted over 35 km single mode fiber, respectively.

2006-01-01

85

Enhancement of PVC/ENR blend properties by poly(methyl acrylate) grafted oil palm empty fruit bunch fiber

British Library Electronic Table of Contents (United Kingdom)

Effect of oil palm empty fruit bunch (OPEFB) fiber and poly(methyl acrylate) grafted OPEFB on several mechanical properties of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blends using HAKEE Rheomixer at the rotor speed of 50 rpm, mixing temperature 150degreeC, and mixing period of 20 min. The fiber loadings were varied from 0 to 30% and the effect of fiber content in the composites on their ultimate tensile strength (UTS), Youngs modulus, elongation at break, flexural modulus, hardness, and impact strength were determined. An increasing trend was observed in the Youngs modulus, flexural modulus, and hardness with the addition of grafted and ungrafted fiber to the PVC/ENR blends. However the i...

2008-01-01

86

Spectroscopic characteristics of erbium and ytterbium-activated laser media

Measurements and calculations of M-shell X-ray production in Er, Yb and Lu by 0.75-6 MeV He ions

Judd-Ofelt parameters (?2 = 5.09?10-20, ?4 0.92?10-20, and ?6 = 0.63?10-20 cm2) and oscillator strengths of fundamental optical transitions involved in lasing at wavelength 1.54 ?m have been calculated for borosilicophosphate glass co-activated with Er3+ and Tb3+ ions based on experimental luminescence and absorption spectra and refractive indices. The results were used to determine the emission (6?10-23 cm2) and absorption (5?10-21 cm2) cross sections for lambda = 1.54 ?m and the gain cross section as a function of inverse population levels. (authors)

2009-01-01

87

SARCOLEMMAL INVAGINATIONS CONSTITUTING THE T SYSTEM IN FISH MUSCLE FIBERS

M-shell X-ray production cross sections for the light rare-earth elements of {sup 68}Er, {sup 7}Yb and {sup 71}Lu have been measured for incident {sup 4}He{sup +} ions in the energy range from 0.75 to 6 MeV. The measured X-ray production cross sections are compared to the predictions of the First Born approximation, the ECPSSR theory and the ECUSAR theory. A comparison of the ytterbium M-shell X-ray production cross sections with these theories is made for two different sets of fluorescence yields and Coster-Kronig factors that are further modified for multiple ionization.

2005-12-15

88

Retinal nerve fiber hypertrophy in ataxia of Charlevoix-Saguenay patients

Striated muscle fibers from the body and tail myotomes of a fish, the black Mollie, have been examined with particular attention to the sarcoplasmic reticulum (SR) and transverse tubular (or T) system....Full Text Available

1964-09-01

89

Receptor Binding Sites and Antigenic Epitopes on the Fiber Knob of Human Adenovirus Serotype 3

PurposeTo present full ophthalmologic examination and retinal nerve fiber layer (RNFL) photographs of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) patients...Full Text Available

90

Pressure driven spinning: A multifaceted approach for preparing nanoscaled functionalized fibers, scaffolds, and membranes with advanced materials

The adenovirus fiber knob causes the first step in the interaction of adenovirus with cell membrane receptors. To obtain information on the receptor binding site(s), the interaction of labeled cell...Full Text Available

1998-11-01

91

Measurements and elimination of Cherenkov light in fiber-optic scintillating detector for electron beam therapy dosimetry

Electrospinning, a flexible jet-based fiber, scaffold, and membrane fabrication approach, has been elucidated as having significance to the heath sciences. Its capabilities have been most impressive...Full Text Available

92

Macular and retinal nerve fiber layer thickness in Japanese measured by Stratus optical coherence tomography

In this study, a miniature fiber-optic radiation detector has been developed using a water-equivalent organic scintillator for electron beam therapy dosimetry. Usually, two kinds of light signals such as fluorescent and Cherenkov lights are generated in a fiber-optic radiation detector when a high-energy electron beam is irradiated. The fluorescent light signal is produced in the scintillator and is transmitted through a plastic optical fiber to a remote light-measuring device such as a PMT or a photodiode. The Cherenkov light could be also produced in the plastic optical fiber itself and be detected by a light-measuring device. Therefore, it could cause problems or limit the accuracy of the detection of a fluorescent light signal that is proportional to dose. The objectives of this study are to measure, characterize and eliminate Cherenkov light generated in a plastic optical fiber ...

2007-08-21

93

Imaging of calcium transients in skeletal muscle fibers.

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

2007-06-01

94

Felting Process for Making Combustible Cartridge Cases.

Epifluorescence images of Ca2+ transients elicited by electrical stimulation of single skeletal muscle fibers were studied with fast imaging techniques that take advantage of the large fluorescence...Full Text Available

1991-01-01

95

Effects of Age on Optical Coherence Tomography Measurements of Healthy Retinal Nerve Fiber Layer, Macula and Optic Nerve Head

A cartridge case is made by making up an aqueous slurry of cellulosic fibers, forming the fibers into a mat and molding the mat or preform into final shape by use of a die at up to 165 degrees F.

1965-01-01

96

Detection and Analysis of Tumor Fluorescence Using a Two-Photon Optical Fiber Probe

PurposeTo determine the effects of age on global and sectoral peripapillary retinal nerve fiber layer (RNFL), macular thicknesses and optic nerve head (ONH) parameters...Full Text Available

2009-06-01

97

Synthesis of polyacrylonitrile (PAN) with different stereoregularity by urea radiation inclusion polymerization and its application to carbon fiber

The utility of a two-photon optical fiber fluorescence probe (TPOFF) for sensing and quantifying tumor fluorescent signals was tested in vivo. Xenograft tumors were developed in athymic mice using MCA207...Full Text Available

2004-06-01

98

Radiation hardness of plastic scintillating fiber

Application to carbon fiber started in this Year. In this paper, a spinning and calcination process are explained. Fiber was obtained by wet spinning of the PAN solution. Ten solvents were tested and the results proved that dimethyl sulfoxide (DMSO) was the best solvent. Glycerine was used as a coagulating bath. The thin fiber (10 to 50 denier) was produced under the conditions of about 20wt% concentration at about 110degC. Heat-treat temperature was about 270 to 275degC. The viscosity-tacticity relationship and T{sub sol} vs. inverse tacticity were shown in the paper. (S.Y.)

1998-01-01

99

Preparation and characterization of poly(methylmethacrylate-coglycidyl methacrylate)/n-hexadecane nanocapsules as a fiber additive for thermal energy storage

We report on measurements of radiation hardness of the plastic scintillating fiber SCSF-81. Fibers were irradiated with "6"0Co #gamma#-rays and fast neutrons up to 105 Gy and up to 5 x 1013 n/cm"2, respectively. Deterioration of the attenuation length of the scintillating fiber was studied. Some significant deterioration was observed at the integrated dose of about 1 x 103 Gy and at the integrated neutron flux (neutron fluence) of about 1 x 1012 n/cm"2 for #gamma#-ray and neutron irradiation, respectively. (author).

100

OPTIMIZATION OF EDDY CURRENT PROBES FOR NDT OF ...

Full Text Available

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101

Long-term hygrothermal effects on damage tolerance of hybrid composite sandwich panels

... Accession Number : ADD321199. Title : OPTIMIZATION OF EDDY CURRENT PROBES FOR NDT OF CARBON FIBER COMPOSITES. ...

1985-04-01

102

Kevlar, the 'universal fiber'. Properties and applications in industry, sports and recreation. Kevlar - die 'Alleskoenner-Faser'. Eigenschaften und Anwendung in Industrie, Sport und Freizeit

A sandwich construction, composed of hybrid carbon-glass fiber-reinforced plastic skins and a

1995-01-01

103

Industrial processing of complex fluids: Formulation and modeling

This article gives a survey of the history, properties and applications of 'Kevlar' aramide fibers. For example, the 'Kevlar' para-aramide fiber is used in compound materials in ship-, aircraft- and vehicle construction. 'Kevlar' is used as a replacement for asbestos, for example in brakes, clutches and seals or as rubber reinforcement (tyres, conveyor belts, hoses). The aramide fibers also offer manufacturers of ropes, hawsers and cables a near ideal range of properties. (MM).

1988-12-01

104

Femtosecond Photonics: Fundamental Phenomena and ...

The production of many important commercial materials involves the evolution of a complex fluid through a cooling phase into a hardened product. Textile fibers, high-strength fibers(KEVLAR, VECTRAN), plastics, chopped-fiber compounds, and fiber optical cable are such materials. Industry desires to replace experiments with on-line, real time models of these processes. Solutions to the problems are not just a matter of technology transfer, but require a fundamental description and simulation of the processes. Goals of the project are to develop models that can be used to optimize macroscopic properties of the solid product, to identify sources of undesirable defects, and to seek boundary-temperature and flow-and-material controls to optimize desired properties.

1997-08-01

105

Dyeability and Functionality of Pine Needles Extract (part I) -Characteristics of Pine Needles Extract and Dyeing Properties of Cellulose Fiber-

... concentrated on the construction of switches using fiber ... been chosen for a switch realized in ... of these techniques using acousto-optic modulators or ...

1992-02-10

106

Development Document for Proposed Effluent Limitations Guidelines and New Source Performance Standards for the Organic Chemicals and Plastics and Synthetic Fibers Industry.

Full Text Available

2011-02-01

107

Design and Manufacture of Rigid Combustible Propelling ...

No abstract available.

1983-01-01

108

Complexing of ruthenium during sorption by a graft copolymer of a polyacrylonitrile fiber with poly-2-methvl-5-vinylpyridine (PAN-MVP)

... Descriptors : *Combustible cartridge cases, *Nitrocellulose, *Propelling charges, *Ammunition containers, Felts, Munitions industry, Fibers, Acrylic ...

1983-06-01

109

Carbon Fiber Reinforced Glass Matrix Composites for Satellite ...

This paper studies the sorption of chlorine complexes of ruthenium (IV) on the graft copolymer of a polyacrylonitrile fiber with poly-2-methyl-5-vinylpyridine (PAN-MVP). The composition of the fiber is illustrated. It is shown that sorption of chlorine complexes of ruthenium (IV) from acid solutions by a pyridine fiber sorbent takes place according to an anion-exchange mechanism and is due to the formation of compounds of the diamine type (Ru(RPy)/sub 2/Cl/sub 4/).

1985-05-20

110

Quick Discrimination of A_delta and C Fiber Mediated Pain Based on Three Verbal Descriptors

... The ultimate compressive strength (UCS) for the HMU/BSG composite is essentially equivalent to the tensile strength exhibited by this system. ...

1992-06-01

111

Production of high porous fibrous materials on the base of VT6 titanium alloy long-dimension fibers

BackgroundA_δ and C fibers are the major pain-conducting nerve fibers, activate only partly the same brain areas, and are differently involved in pain syndromes....Full Text Available

112

Partially-carbonized polyacrylonitrile filter

VT6 titanium alloy long-range fibers have been extracted from the suspended melt drop with the following high-rate solidification. Formation of the structure of fibrous porous material prepared from these fibers has been studied. 7 refs.; 5 figs.; 2 tabs.

113

Monolithic stabilized Yb-fiber All-PM laser directly delivering nJ-level femtosecond pulses

A filter for extracting solids and liquids from gaseous combustion exhausts comprises a textile filter element formed of polyacrylonitrile fibers oxidized by careful heat treatment and comprising approximately 61% carbon after treatment. The filter may be woven, knitted or formed as a batting of randomly-oriented fibers. Abrasion resistant coatings and lubricants for the fibers are disclosed. The filter material is especially useful as a filter bag.

1984-04-24

114

DEFF Research Database (Denmark)

We present a monolithic, self-starting, all-PM, stabilized Yb-fiber laser, pulse-compressed in a hollow-core PM photonic crystal fiber, providing the 370 fs pulses of 4 nJ energy with high mode quality.

2008-01-01

115

In situ microscopic analysis of asbestos and synthetic vitreous fibers retained in hamster lungs following inhalation.

Electrospun carbon fiber mat with layered architecture for anode in microbial fuel cells

Hamsters breathed, nose-only, for 13 weeks, 5 days/week, 6 hr/day, either man-made vitreous fiber (MMVF)10a, MMVF33, or long amosite asbestos at approximately 300 World Health Organization (WHO) fibers/cc...Full Text Available

1999-05-01

116

British Library Electronic Table of Contents (United Kingdom)

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

2011-01-01

117

Detection device for high explosives

Strongly enhanced critical current density in MgB{sub 2}/Fe tapes by stearic acid and stearate doping

A portable fiber optic detector that senses the presence of specific target chemicals by electrostatically attracting the target chemical to an aromatic compound coating on an optical fiber. Attaching the target chemical to the coated fiber reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

1992-01-01

118

Valence transition and magnetic ordering in Sn doped EuPd/sub 2/Si/sub 2/

Fe-sheathed MgB{sub 2} tapes with cheap stearic acid, Mg stearate and Zn stearate doping were prepared through the in situ powder-in-tube method. It is found that J{sub c}, H{sub irr} and H{sub c2} were significantly enhanced by doping. Compared to the pure tapes, J{sub c} for all the doped samples was improved by more than an order of magnitude in a high-field regime. At 4.2 K, the transport J{sub c} reached 2.02 x 10{sup 4} A cm{sup -2} at 10 T for the Zn stearate doped tapes and 3.72 x 10{sup 3} A cm{sup -2} at 14 T for the stearic acid doped samples, respectively. Moreover, at 20 K, H{sub irr} for the Zn stearate doped tape achieved 10 T, which is comparable to that of the commercial NbTi at 4.2 K. The improvement of J{sub c}-H properties in doped samples can be attributed to the increase of H{sub c2} resulting from the incorporation of ...

2007-05-15

119

Fabrication of a MnCo2O4/gadolinia-doped Ceria (GDC) Dual-phase Composite Membrane for Oxygen Separation

The sharp, temperature induced, continuous valence transition in EuPd/sub 2/Si/sub 2/ is drastically changed by doping with Sn at the Si site up to 5 at.%. Only a first order valence transition occurs for a 3% Sn doped sample and the 2/sup +/ component which survives the valence transition orders magnetically at 4.2 K. No valence transition at all occurs for a 5% Sn doped sample right up to 1.9 K and magnetic ordering sets in around 30 K.

1983-12-01

120

Influence of ion-beam carbon-fiber surface treatment on the angle of wetting by epoxy oligomers

Full Text Available

2010-03-01

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121

A novel graphene nanosheets coated stainless steel fiber for microwave assisted headspace solid phase microextraction of organochlorine pesticides in aqueous samples followed by gas chromatography with electron capture detection

The influence of the regimes of modification of carbon fibers by an argon ion beam on the change in the angle of their wetting by an epoxy oligomer has been investigated. It has been shown that ion-beam treatment of carbon fibers leads to a considerable decrease in the wetting angles (the difference between the wetting angles for non modified and modified fibers is up to 32.2-38.7). Accordingly, there is also an increase in the value of the equilibrium work of adhesion by 36.2-41.6% in the contact zone. It has been established that ion-beam treatment of carbon fibers by argon ions leads to an increase in the shear strength when microplastics based on them are formed. (authors)

122

British Library Electronic Table of Contents (United Kingdom)

In this study, a novel graphene nanosheets (GNSs) coated solid phase microextraction (SPME) fiber was prepared by immobilizing microwave synthesized GNSs on a stainless steel wire. Microwave synthesized GNSs were verified by X-ray diffraction, field emission-scanning electron microscopy (FE-SEM) and transmission electron microscope (TEM). GNS-SPME fiber was characterized using FE-SEM and the results showed the GNS coating was homogeneous, porous, and highly adherent to the surface of the stainless steel fiber. The performance and feasibility of the GNS-SPME fiber was evaluated under one-step microwave assisted (MA) headspace (HS) SPME followed by gas chromatography with electron capture detection for five organochlorine pesticides (OCPs) in aqueous samples. Parameters influencing the extra...

2011-01-01

123

Determination of endocrine-disrupting compounds in water by carbon nanotubes solid-phase microextraction fiber coupled online with high performance liquid chromatography.

Oil palm empty fruit bunch (OPEFB) fiber reinforced PVC/ENR blend-electron beam irradiation

The commercial solid phase microextraction (SPME) fibers are not stable enough in organic solvent and tend to swell and strip off from the silica fiber in the high performance liquid chromatography (HPLC) mobile phase, and therefore the application of SPME coupled online with HPLC is limited. In this study, an SPME fiber coated with single walled carbon nanotubes (SWCNTs), prepared by means of electrophoretic deposition, was coupled on line to HPLC for the determination of four endocrine-disrupting compounds, i.e. bisphenol A (BPA), estrone (E(1)), 17?-ethynylestradiol (EE(2)) and octylphenol (OP), in aqueous samples. The results showed that the SWCNTs coating on the prepared fiber did not swell and strip off from the platinum fiber throughout the experiment, thus indicating a high resistance to the HPLC mobile phase, the mixture of water and acetonitrile. The SWCNTs ...

2011-07-27

124

High performance fiber filtration and its fluid flow

The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 deg. C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young's modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young's modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB ...

2007-12-15

125

Structural, optical, photocatalytic and antibacterial activity of zinc oxide and manganese doped zinc oxide nanoparticles

A new filtration process using acrylic fiber has been developed which has wide applications in water works, sewage water treatment and waste water treatment facilities. Instead of sand, the common filter media in conventional systems, this new system uses long, fine acrylic fibers. Compared with a conventional system, the filtration speed and suspended solids (SS) retention of the new system have been increased 500% from 120--200 m/d to 400--1,200 m/d and from 2--3 kg/m{sup 2} to 5--20 kg/m{sup 2}, respectively. In addition, the backwash time has been decreased 60%, from 20--30 min to 10 min. As SS retention increase, the empty space between the fibers (fiber void) decreases and pressure drops due to the high filtration rate. Thus the pressure decreases rapidly after a certain period of filtration because of the increased SS retention cause fiber compression. This system is ...

1994-12-31

126

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...

2010-01-01

127

Materials design for semiconductor spintronics by ab initio electronic-structure calculation

Preparation, characterization and properties of thermochromic tungsten-doped vanadium dioxide by thermal reduction and annealing

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 ...

2003-04-01

128

Influence of vanadium doping on the electrochemical behaviour of MnO{sub 2} rutile; Influence du dopage par le vanadium sur le comportement electrochimique de MnO{sub 2} rutile

Thermochromic tungsten-doped vanadium dioxide (VO2) powders were successfully synthesized by thermal reduction using V2O5 as a vanadium precursor. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results indicated that W was successfully doped into the crystal lattice of VO2 matrix, and prepared tungsten-doped VO2 had a rod-like morphology. The effects of reducing temperature and annealing temperature on the crystallographic structures were also discussed. The phase transition temperature (Tt) of VO2 could be simply tuned by changing the doping concentration of tungsten. When the doping concentration was 1.58 mol%, the Tt could be reduced to 37.8 oC from initial 69.5 oC, suggesting that tungsten-doped VO2 possesses prominent ...

2010-08-20

129

Thermal-resistant radiation sensing system using optical fiber for monitoring progress of chemical decontamination

Vanadium doped manganese bi-oxide has been obtained from a solution containing both cations. The X-ray diffraction of this material indicates a rutile-type phase but the enlargement of some lines supports the existence of several lattice defects. Also the particle size of the doped material is significantly smaller than the one of the non-doped material obtained in the same conditions. The presence of pentavalent vanadium inside the lattice leads to a small amount of trivalent manganese. Electron microscopy shows the existence of defects which have a tendency of becoming well-ordered and to stabilize a sur-structure. At ambient temperature, the electrochemical behaviour of doped manganese bi-oxide is greatly improved when compared to the non-doped phase. This behaviour is due to the presence of numerous lattice defects and to the smaller size of crystallites. In polymer batteries, ...

1996-12-31

130

Experimental evaluation of angularly-variable fiber geometry for targeting depth-resolved reflectance from layered epithelial tissue phantoms

A thermal-resistant radiation sensing system using optical fiber has been developed. The system is for monitoring progress of chemical decontamination and able to measure the gamma-ray level in a hot solution of decontamination chemicals in situ. Our sensor head makes use of thermal-resistant NaI (T1) and it is connected to an optical fiber bundle. Scintillation photons pass from the NaI (T1) into the end of the bundle. This part of the system can withstand temperatures of over 100degC. At the far end of the optical fiber bundle, the scintillation photons are converted into fluorescent photons using a wavelength-shifting fiber. These photons are transferred to a distant photomultiplier tube through two thin transparent optical fibers. Furthermore, we propose a self-compensation technique for the dependence of scintillator sensitivity on. This compensation method is based on the ...

1999-07-01

131

Preparation of NiZn-ferrite nanofibers by electrospinning for DNA separation

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

2007-03-01

132

An optical fiber methane sensing system employing a two-step reference measuring method

We present the synthesis, magnetic and UV spectrometry of NiZn-ferrite nanofiber. The single phase of spinel ferrite was obtained at 600 {sup o}C. The NiZn-ferrite fibers fabricated by an electrospinning process were formed as a polygonal grain growth with firing temperature in fiber matrix. It appeared that the saturation magnetization (M{sub S}) of NiZn-ferrite nanofiber was dependent on Ni/Zn molar ratio which is similar to that of the inverse spinel ferrites. The NiZn-ferrite fibers showed good DNA adsorption efficiency that can be modified and utilized for DNA separation with magnetic nanofiber as a novel material in clinical applications.

2009-05-15

133

British Library Electronic Table of Contents (United Kingdom)

An optical fiber methane sensing system utilizing a super-luminescent diode (SLD) in the 1.33-mm band and a fiber Fabry-Perot tunable filter (FFP-TF) is developed. A two-step reference measuring method, which is based on differential absorption technique, is employed; a reference channel is introduced to eliminate the fluctuation of the illuminant spectrum, and the reference wavelength acquired by tuning the FFP-TF is introduced to eliminate the environmental influence. The two-step reference measuring method has improved the reliability and stability of the system. A minimum detectable methane concentration of 0.3% has been experimentally achieved.

2008-01-01

134

An investigation of the retention of some radioelements on natural fibers

Radiochemical separation of no-carrier-added {sup 177}Lu as produced via the {sup 176}Ybn,{gamma}{sup 177}Yb{yields}{sup 177}Lu process

The retention of radio-Eu, Go, Cs and Sr, at the tracer level, on raw fibers produced from hemp, linen and Jute plants was investigated. The study was conducted from different media including: sea and tap waters, sodium chloride and nitric acid solutions of different Ph. The percentage retention and elution, on prolonged contact, varied from one element to another depending on conditions. Extraction chromatography columns, using these fibers as supporting material were also experimented. Results were discussed together with possible applications. 7 tabs.

135

Magnetic moment measurements of gadolinium, holmium and ytterbium tartrate trihydrate crystals

The {sup 176}Ybn,{gamma}{sup 177}Yb-{beta}{sup -}{yields}{sup 177}Lu process was investigated to provide no-carrier-added (nca) {sup 177}Lu. The radiochemical separation of the {sup 177}Lu from the macro-amounts of the ytterbium target based on the cementation process, i.e. the selective extraction of Yb by Na(Hg) amalgam from Cl{sup -}/CH{sub 3}COO{sup -} electrolytes, followed by a final cation exchange purification. The cementation separation process provides a decontamination factor of Yb(III) of 10{sup 4}, the cation exchange purification adding a decontamination factor of >10{sup 2}. The nca {sup 177}Lu is available in radiochemically pure form despite the chemical similarity of the lanthanides with 75{+-}5% overall separation yield within 4-5 h. It can be used to synthesise nca {sup 177}Lu labelled radiotherapeuticals.

2000-09-15

136

British Library Electronic Table of Contents (United Kingdom)

Magnetic moment and susceptibility of single crystals of rare earth tartrates of the type R(C4H4O6)(C4H5O6)3H2O (where R = Gd, Ho, and Yb), using a vibration sample magnetometer are reported. The experimental values of molar susceptibilities for Gd(C4H4O6)(C4H5O6)3H2O, Ho(C4H4O6)(C4H5O6)3H2O, and Yb(C4H4O6)(C4H5O6)3H2O are 2.58x10-2, 4.66x10-2, and 8.03x10-3 (in cgs em units), respectively. The calculated effective magnetic moments are in good agreement with the theoretical predictions on rare earth ions.

2008-01-01

137

[Changes in the mucous membrane of the esophagus and stomach in patients with chronic alcoholism during the period of acute alcoholic intoxication (according to fiber endoscopy and spot biopsy data)].

Structure and morphology changes during nylon 66 fiber deformation via synchrotron x-ray scattering techniques

PMID:4428360

1974-01-01

138

Structural Response of Marine Sandwich Panels to Uniform ...

Morphological and structural changes of nylon 66 were evaluated during a continuous heat-draw process. Results are discussed.

1996-12-31

139

Search Results - NASA Technical Reports Server

... Composite sandwich panels with fiber reinforced plastic (FRP) faces and low 3 density foam cores are fast becoming the structural material of ...

1990-06-01

140

Quartz fiber calorimetry and calorimeters

The influence of ablation on stagnation region convective heating for ... and thermal properties of this fiber depend on the fluorination process ... However, these properties are between those of graphite and those of PTFE (Teflon). ...

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

141

Performance evaluation of multi-fiber optical packet switches

Quartz fiber calorimetry is a technique the signal generation mechanism of which is based on the Cherenkov effect. In this article we try to give a comprehensive overview of the subject. We start with a general introduction to calorimetry where the basic elements that characterize the development of electromagnetic and hadronic showers are discussed. Then we describe in detail the operation principle and the properties of calorimeters equipped with quartz fibers. The main advantages of this type of calorimeters are the radiation hardness, the fast response and the compact detector dimensions, features that derive from the quartz material and the specific mechanism of operation. A section is devoted to presenting the quartz fiber calorimeters that have been built or planned to in various experiments to operate as centrality detectors, trigger detectors, luminosity monitors or general purpose very forward calorimeters.

2004-01-01

142

British Library Electronic Table of Contents (United Kingdom)

Multi-fiber WDM networks are becoming the major telecommunication platforms for transmitting exponentially increasing data traffic. While today's networks are mainly providing circuit-switched connections, optical packet-switching technologies have been investigated for years, aiming at achieving more efficient utilizations of network resources. In this paper, we have evaluated, for the first time, the packet-loss performance of multi-fiber optical packet switches (MOPS). Our main contributions are threefold. Firstly, we have proposed simple and accurate analytical models for analyzing packet-loss performance of (i) the most fundamental MOPS configuration, (ii) MOPS equipped with fiber delay lines (FDLs) and (iii) shared wavelength converters (SWCs). Secondly, we have shown that the MOPS n...

2007-01-01

143

Operator Alertness/Workload Assessment Using Stochastic ...

NMR characterization of composition and fiber size parameters of the sugarcane Eva/bagasse composites

... potential propagation in terminal nerve fibers or at the neuromuscular ... means of prosthesis control (Graupe, et al, 1975). ... parallel interface, a joystick ...

1984-04-30

144

Influence of short carbon fiber content on mechanical and dielectric properties of Cfiber/Si3N4 composites

... Commission, Rio de Janeiro Rio de Janeiro, RJ (Brazil) 26-27 Nov 1998 1

1998-11-26

145

British Library Electronic Table of Contents (United Kingdom)

Cfiber/Si3N4 composites were prepared by hot-pressed sintering using a-Si3N4 powders, short carbon fibers and sintering additives as starting materials. The mechanical and dielectric properties of these composites were studied. When the short carbon fiber content of the composites increases from 0 to 1wt.%, the fracture toughness increases from 3.456 to 4.203MPam1/2, and both the real and imaginary part of permittivity increase greatly over the frequency range 8.2-12.4GHz. These effects were due to the anisotropy of short carbon fibers.

2007-01-01

146

Influence of recycling and temperature on the swelling ability of paper

British Library Electronic Table of Contents (United Kingdom)

Hornification is the loss of fiber wall swelling which is detrimental to subsequent recycling resulting from drying. It is known that dried fibers lose their conformability and swelling capacity. The effect of recycling treatment on the swelling ability of hardwood bleached kraft pulp fibers was determined. Modelling paper recycling, sheets were recycled using heat treatment (23?C, 60?C, 100?C). The results were compared with those for natural fibers from bleached kraft pulp. Swelling kinetics of sheets was measured by a modified method monitoring interactions of pulp with water. Swelling ability decreased during the recycling in comparison with never-recycled pulp at all temperatures. Recycling of sheets caused only small changes in the cupri-ethylene-diamine viscosity, however, the water...

2011-01-01

147

Effects of carbon fiber surface treatment on the tribological properties of 2D woven carbon fabric/polyimide composites

British Library Electronic Table of Contents (United Kingdom)

Polyacrylonitrile (PAN)-based carbon fabric (CF) was modified with strong HNO3 oxidation and then introduced into polyimide (PI) composites. The friction and wear properties of the carbon fabric reinforced polyimide composites (CFRP), sliding against GCr15 stainless steel rings, were investigated on an M-2000 model ring-on-block test rig under dry sliding. Experimental results revealed that the carbon fiber surface treatment largely reduced the friction and wear of the CFRP. Compared with the untreated ones, the surface-modified CF can enhance the tribological properties of CFRP efficiently due to the improved adhesion between the CF and the PI matrix. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) study of the carbon fiber surface showed that the fiber surfa...

2009-01-01

148

Effect of carbon fiber surface treatments on the flexural strength and tribological properties of short carbon fiber/polyimide composites

British Library Electronic Table of Contents (United Kingdom)

Pitch-based short carbon fibers (CFs) were treated by air oxidation and cryogenic nitrogen, respectively. Thereafter the treated and untreated CFs were incorporated into polyimide (PI) matrix to form composites. The CFs before and after treatment were examined by XPS and SEM.The flexural strength of the specimen was determined in a three-point test machine and the tribological properties of PI composites sliding against GCr15 steel rings were evaluated on an M-2000 model ring-on-block test rig. The results show that the surface of the treated CFs became rougher. Lots of active groups formed on the CF surface after air oxidation.The treatment can effectively improve the mechanical and tribological properties in their PI composites due to the enhanced fiber-matrix interfacial bonding. Copyri...

2008-01-01

149

Development of a small scintillation detector with an optical fiber for fast neutrons

Development of Material Properties for Slurry Infiltrated Fiber ...

To investigate the characteristics of a reactor and a neutron generator, a small scintillation detector with an optical fiber with ThO_2 has been developed to measure fast neutrons. However, experimental facilities where "2"3"2Th can be used are limited by regulations, and S/N ratio is low because the background counts of this detector are increase by alpha decay of "2"3"2Th. The purpose of this study is to develop a new optical fiber detector for measuring fast neutrons that does not use nuclear material such as "2"3"2Th. From the measured and calculated results, the new optical fiber detector which uses ZnS(Ag) as a converter material together with a scintillator have the highest detection efficiency among several developed detectors. It is applied for the measurement of reaction rates generated from fast neutrons; furthermore, the absolute detection efficiency of this detector was obtained experimentally.

2011-02-01

150

Compression Testing of Continuous P-100 Fiber Reinforced ...

... Page 26 Ultimate compressive strength versus fly ash/cement limits 41 ... 222 El Ultimate compressive strength versus water/(cement + fly ash) 250 ...

1988-09-01

151

Combustion Mechanisms of 25MM Combustible Cartridge.

... The measured elastic modulus was fairly close to the predicted value, but the ultimate compressive strength (UCS) was quite a bit below the MSC ...

1991-10-01

152

Aircraft Survivability: Protecting and Integrating Air and Space ...

... Abstract : The structural features of 25mm combustible cartridge cases, manufactured for this program and having nitrocellulose/resin/fiber ratios of ...

1973-08-01

153

Agricultural production systems and environmental health.

... reliability of fiber optics in preference over space-based systems. ... STC web site at www.aiaa.org/tc ... and improve lethalities of US weapon systems 3 ...

2011-05-15

154

A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

By the turn of the century, American farmers and ranchers will be producing food and fiber through the application of highly sophisticated systems that involve a broad spectrum of relevant factors--from...Full Text Available

1990-06-01

155

8 - NASA Technical Reports Server

The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. (authors)

2008-05-01

156

Selective emitter using porous silicon for crystalline silicon solar cells

The influence of ablation on stagnation region convective heating for ... and thermal properties of this fiber depend on the fluorination process ... However, these properties are between those of graphite and those of PTFE (Teflon). ...

157

Neutron Transmutation Doping of Initially p-type Silicon for Production of Uniformly Doped n-type Silicon

This study is devoted to the formation of high-low-level-doped selective emitter for crystalline silicon solar cells for photovoltaic application. We report here the formation of porous silicon under chemical reaction condition. The chemical mixture containing hydrofluoric and nitric acid, with de-ionized water, was used to make porous on the half of the silicon surface of size 125 x 125 cm. Porous and non-porous areas each share half of the whole silicon surface. H{sub 3}PO{sub 4}:methanol gives the best deposited layer with acceptable adherence and uniformity on the non-porous and porous areas of the silicon surface to get high- and low-level-doped regions. The volume concentration of H{sub 3}PO{sub 4} does not exceed 10% of the total volume emulsion. Phosphoric acid was used as an n-type doping source to make emitter for silicon solar cells. The measured emitter sheet resistances at the high- and ...

2009-06-15

158

Neutron Transmutation Doping of Initially p-type Silicon for Production of Uniformly Doped n-type Silicon

Neutron transmutation doping(NTD) for producing ntype silicon semiconductor is based on the conversion of the Si-30 isotope into phosphorus atom by neutron absorption reaction. By using this method, silicon semiconductors with extremely uniform n-type dopant distributions can be produced, and this is the dominant advantage of NTD compared with the conventional chemical doping. HANARO has two vertical holes for NTD, and the commercial NTD service for 5 and 6 inch silicon ingots has been going on at the NTD2 hole. Generally, NTD method is applied to the initially n-type silicon material. But, an initially p-type silicon material can also be used for the production of uniformly doped n-type silicon by using NTD method. Therefore, in this work, we investigated the relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material. Thereafter, we established the methodology ...

2007-10-15

159

Thulium-doped vanadate crystals: Growth, spectroscopy and laser performance

Neutron transmutation doping(NTD) for producing ntype silicon semiconductor is based on the conversion of the Si-30 isotope into phosphorus atom by neutron absorption reaction. By using this method, silicon semiconductors with extremely uniform n-type dopant distributions can be produced, and this is the dominant advantage of NTD compared with the conventional chemical doping. HANARO has two vertical holes for NTD, and the commercial NTD service for 5 and 6 inch silicon ingots has been going on at the NTD2 hole. Generally, NTD method is applied to the initially n-type silicon material. But, an initially p-type silicon material can also be used for the production of uniformly doped n-type silicon by using NTD method. Therefore, in this work, we investigated the relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material. Thereafter, we established the methodology ...

2007-10-01

160

British Library Electronic Table of Contents (United Kingdom)

This work is concentrated on growth, spectroscopy and laser performance of thulium-doped vanadate crystals. At the beginning the growth techniques are analyzed and then the matrix of vanadates crystal, its structure and physicochemical properties are explained together with the rare earth activators influence. Detailed spectroscopy of the thulium-doped vanadate crystals then follows. On the background of this theoretical analysis and state of the art of the subject the description of thulium vanadate lasers (especially Tm:YVO"4, Tm:GdVO"4, and Tm:LuVO"4) together with their generated output radiation characteristics are presented.

2011-01-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

161

Temperature Dependences of Leakage Currents of ZnO Varistors Doped with Rare-Earth Oxides

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.

2010-01-01

162

Surface doping of conjugated polymers by graphene oxide and its application for organic electronic devices

Impedance spectroscopy study with H-doped ammonium uranylphosphate self supported membranes

Surface doping of conjugated polymers is realized by depositing a thin layer of graphene oxide (GO) on top of the polymers. The high proton density and the unique 2D structure of GO facilitate the protonic surface doping of conjugated polymers to achieve high conductivities. This finding represents a new strategy for improving charge transport across the metal/conjugated polymer interface to achieve much improved performance in organic solar cells. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

2011-04-26

163

Electron paramagnetic resonance of nitroxide-doped magnetic fluids

Equivalent circuit and electrical parameters for H-doped NH_4UO_2PO_4.3H_2O self supported membranes have been determined by impedance spectroscopy. The measurements were carried out with a dry membrane, at different temperatures, and a wet membrane in contact with different electrolyte solutions. Resistance values for the dry membrane decrease with temperature increase, which agrees with the weak protonic character of the H-doped ammonium uranylphosphate. On the other hand, differences in the electrical parameters, depending on the electrolyte considered were also obtained and are attributed to different conduction mechanisms. (Author).

164

The effect of neutron dose and boron doping on X-ray diffraction in neutron irradiated silicon and germanium

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.

2002-11-01

165

The Effect of Boron on the Mechanical Behavior of Copper ...

(1973). United Kingdom Baldwin, TO Dunn, JE Southern Illinois Univ.,

166

Nitrogen doping into titanium dioxide by the sol?gel method using nitric acid

... 500 ppm, boron increases the 0.2% offset strength; results show that boron doping does not appreciably affect ultimate compressive strength; for 0 ...

167

British Library Electronic Table of Contents (United Kingdom)

N-doped TiO2 has been prepared by use of sol?gel systems containing titanium alkoxide, with nitric acid as the nitrogen source. The time needed for gelation of the systems was drastically reduced by ultrasonic irradiation. The peaks assigned to the nitrate and nitrous ions were observed by FT-IR measurement during the sol?gel reaction. The N-doping was confirmed by the observation of N?O peaks in the XPS spectrum of the sample heated at 400??C. The nitrate ion acted as an oxidizer of the ethanol solvent and titanium species. The TiO2 became doped with nitrogen oxide species as a result of reduction of nitrate ion incorporated into the dried gel samples. These results indicated that the added nitric acid was reduced during the sol?gel transition and heating process, and the resulting NO spe...

2011-01-01

168

Microstructure and properties of ultrafine WC-10Co composites with chemically doped VC

British Library Electronic Table of Contents (United Kingdom)

Vanadium carbide is the most effective grain growth inhibitor for ultrafine WC-Co composites due to its high solubility and mobility in the cobalt phase at relatively low temperatures; however, there are still some debates over the best way to introduce it into the WC-Co formulation. In this paper, the differences between admixed and chemically doped grain growth inhibitors on the microstructural development and properties of an ultrafine WC-10Co composite are discussed. The densification rate of chemically doped samples is slower in the early stage of sintering and the WC grain sizes of the sintered alloys are finer than those of admixed samples, leading to the increase of hardness and transverse rupture strength of the sintered alloys. The effectiveness of the chemically doped inhibitor ...

2011-01-01

169

Microscopic Origin of the Phenomenological Equilibrium ''Doping Limit Rule'' in n -Type III-V Semiconductors

Large Magnetic Moments of Arsenic-Doped Mn Clusters and their Relevance to Mn-Doped III-V Semiconductor Ferromagnetism

The highest equilibrium free-carrier doping concentration possible in a given material is limited by the ''pinning energy'' which shows a remarkable universal alignment in each class of semiconductors. Our first-principles total energy calculations reveal that equilibrium n -type doping is ultimately limited by the spontaneous formation of close-shell acceptor defects: the 3- -charged cation vacancy in AlN, GaN, InP, and GaAs and the 1- -charged DX center in AlAs, AlP, and GaP. This explains the alignment of the pinning energies and predicts the maximum equilibrium doping levels in different materials. (c) 2000 The American Physical Society

2000-02-07

170

Experimental and analytical study of saturation current density of laser-doped phosphorus emitters for silicon solar cells

We report electronic and magnetic structure of arsenic-doped manganese clusters from density-functional theory using generalized gradient approximation for the exchange-correlation energy. We find that arsenic stabilizes manganese clusters, though the ferromagnetic coupling between Mn atoms are found only in Mn$_2$As and Mn$_4$As clusters with magnetic moments 9 $\\mu_B$ and 17 $\\mu_B$, respectively. For all other sizes, $x=$ 3, 5-10, Mn$_x$As clusters show ferrimagnetic coupling. It is suggested that, if grown during the low temperature MBE, the giant magnetic moments due to ferromagnetic coupling in Mn$_2$As and Mn$_4$As clusters could play a role on the ferromagnetism and on the variation observed in the Curie temperature of Mn-doped III-V semiconductors.

2005-01-01

171

British Library Electronic Table of Contents (United Kingdom)

Heavily doped emitters with low saturation current density are of particular interest for selective emitter solar cells. These emitters can be obtained by laser doping through the phosphosilicate glass layer formed after thermal diffusion from POCl3 gas. The experimental results show that in contrast to purely POCl3 furnace-diffused emitters, the saturation current density of laser-doped emitters does not increase linearly as sheet resistance decreases, but rather features two distinct regimes. In one of these regimes, the saturation current density is found to decrease as the sheet resistance decreases, reaching values lower than those of furnace emitters. This peculiar behaviour was explained by both qualitative analysis and numerical simulations.

2011-01-01

172

Electrooxidation of orange 16 reactive dye on diamond electrode doped with boron and comparison with ozonization

Effects of lithium iodide doping on devolatilization characteristics of brown coals; Yoka lithium no tenka ga kattan no kanetsu henka katei ni oyobosu eikyo

Portuguese 2008 2 p. Brazil Silva, Diogo Lima da Andrade, Leonardo

2008-05-26

173

Double perovskite catalysts for oxidative coupling

In order to discuss effects of lithium iodide (LiI) doping on condensation structure of brown coals during heating, spectral changes were measured by using an in-situ FT-IR. It was found that the LiI doping accelerates weight reduction due to heating, and the doping effect is affected by coal structure. Both of Loy Yang (LY) coal and its LiI doped coal (DLY) had absorption intensity of the FT-IR spectra decreased with rising temperature, and the absorption center belonging to an OH group shows different shifts between the LY and DLY coals. This indicates that the LiI doping has affected the change in hydrogen bonding patterns associated with heating. Both of South Banko (SB) and LY coals had the absorption spectral intensity in the OH group decreased as the weight reduction (conversion) rate increased. Reduction in the OH groups associated with heating is caused by volatilization ...

1996-10-28

174

Boron transient enhanced diffusion in heavily phosphorus doped silicon

Alkali metal doped double perovskites containing manganese and at least one of cobalt, iron and nickel are useful in the oxidative coupling of alkane to higher hydrocarbons.

1991-01-01

175

A novel single-step synthesis of N-doped TiO"2 via a sonochemical method

A study has been made of B transient enhanced diffusion (TED) in heavily P-doped Si using secondary ion mass spectroscopy (SIMS) and positron annihilation spectroscopy (PAS). The P-doped silicon was implanted with boron ions of 40 keV energy to a dose of 3 x 10"1"4 cm"-"2, and then annealed at temperatures ranging from 700--1,000 C in a N_2 ambient for varying durations. As P doping concentration increased from 3 x 10"1"9 to 1 x 10"2"0 cm"-"3, boron diffusivity and the immobile boron fraction decreased. The experimental results are inconsistent with the predictions of the Fermi-level model and suggest that the clustering between B atoms and Si interstitials should be invoked in order to explain the immobile portion of the B peak during TED.

1996-12-02

176

British Library Electronic Table of Contents (United Kingdom)

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

2011-01-01

177

A first principles study on optical transparency mechanism in Dy doped #alpha#-SiAlON ceramics

On the homology of exotic Springer fibers

Dy doped #alpha#-SiAlON ceramics prepared by the hot-pressing method show a high optical transmittance value, >70%, in the infrared region of 1.5-4.5 #mu#m. First principles calculations have been carried out to reveal the underlying transparency mechanism. It is found that the valence shell of doped Dy atoms interacts strongly with the doping states of #alpha#-SiAlON, resulting in the increase in the optical gap from 0.4 to 1.1 eV, which suppresses the photoabsorption in the wavelength region longer than 1.0 #mu#m and leads to the good transparency property. The calculated optical transmission spectra are in good agreement with the corresponding experiments.

2009-11-01

178

Effects of matrix resin and fiber content on behavior of fatigue crack propagation in continuous-fiber-mat reinforced CP-resin composites; Renzoku sen`i mat kyoka CP resin fukugozai no hiro kiretsu denpa tokusei ni oyobosu bozai oyobi sen`i gan`yuritsu no eikyo

We determine the structure of the total homology groups of exotic Springer fibers as affine Weyl group representations. As applications, we provide single top/socle property of standard modules in the exotic Deligne-Langlands correspondence (except for root of unity case), an analogue of Verma's theorem, the coincidence of analytic/geometric gradings in the $C ^{\\infty}$-realization of anti-spherical modules of graded Hecke algebras of type $\\mathsf{BC}$ with unequal parameters, among others.

2011-01-01

179

Comparison of three methods of remote metering of electrical energy: Telephone line, fiber optic, and radio packet. Final report, June 1995--August 1995

The purpose of the present work is to investigate the effects of matrix resin and fiber content on the behavior of fatigue crack propagation in continuous-glass-fiber-mat reinforced CP-resin composites. For this purpose, ductile matrix resin and brittle one are used. These two kinds of resins have the characteristic that the elastic modulus and tensile strength are nearly the same with each other while the elongation is different. The composite specimens are made of these resins and continuous grass fiber mat of 20 wt.% and 60 wt% fiber contents. The fatigue crack propagation test was conducted by using the tapered DCB specimens to control the stress intensity factor range, {delta}K, during the test. The results obtained are as follows; (1) The relation between the crack propagation rate, da/dN, and {delta}K for all the present materials is shown by a straight line in logarithmic representation. (2) For ...

1996-05-15

180

Comparable Postprandial Glucose Reductions with Viscous Fiber Blend Enriched Biscuits in Healthy Subjects and Patients with Diabetes Mellitus: Acute Randomized Controlled Clinical Trial

This report deals with the selection of a data communication system for a remote metering system. It covers the following three types of systems: fiber optic, telephone line, and radio packet. It provides a methodology for selecting a communication system for a given remote metering system and a method for comparing costs.

1998-07-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

181

Photocatalytic self-cleaning properties of cellulosic fibers modified by nano-sized zinc oxide

AimTo compare the blood glucose-lowering effect of a highly viscous fiber blend (VFB) added to a starchy snack on postprandial glycemia between healthy participants and participants...Full Text Available

2008-12-01

182

High-strength fiber-reinforced plastic reinforcement of wood and wood composite

Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol-gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the fiber surface. The electron micrographs show formation of zinc oxide nanoparticles within 10-15 nm in size which have been homogeneously dispersed on the fiber surface. The prepared materials show significant photocatalytic self-cleaning activity, which was monitored by diffuse reflectance spectroscopy. The photoactivity was studied upon measuring the photodegradation of methylene blue and eosin yellowish under UV-Vis ...

2011-03-31

183

Genetic effects of introgression genomic components from Sea Island cotton (Gossypium barbadense L.) on fiber related traits in upland cotton (G. hirsutum L.)

Research and development underway since 1982 has led to the development of a method of reinforcing wood and wood composite structural products (WWC) using high-strength fiber-reinforced plastic. This method allows the use of less wood fiber and lower grade wood fiber for a given load capacity. The first WWC in which reinforcement has been marketed is glulam beams. Marketed under the trade name FiRP{trademark} Reinforced glulam, the product has gained code approval and is now being used in the construction of buildings and bridges in the United States, Japan and other countries. The high-strength fiber-reinforced plastic (FiRP{trademark} Reinforced panel (RP)) has specific characteristics that are required to provide for proper use in WWC`s. This paper discusses these characteristics and the testing requirements to develop code approved allowable design values for carbon, aramid and fiberglass RP`s for ...

1996-12-31

184

British Library Electronic Table of Contents (United Kingdom)

The germplasm with exotic genomic components especially from Sea Island cotton (Gossypium barbadense L. Gb) is the dominant genetic resources to enhance fiber quality of upland cotton (G. hirsutum L., Gh). Due to low efficiency of phenotypic evaluation and selection on fiber quality, genetic dissection of favorable alleles using molecular markers is essential. Genetic dissection on putative Gb introgressions related to fiber traits were conducted by SSR markers with mapping populations derived from a cross between Luyuan343 (LY343), a superior fiber quality introgression line (IL) with genomic components from Gb, and an elite Upland cotton cv. Lumianyan#22 (LMY22). Among 82 polymorphic loci screened out from 4050 SSRs, 42 were identified as putative introgression alleles. A total of 29 fib...

2011-01-01

185

Effects of comonomer and two-step oxidation on production of polyacrylonitrile-based carbon fibers. Polyacrylonitrile kei tanso sen'i no seizo ni okeru sanka jikan ni oyobosu zenkutai sen'i no kyojugo seibun oyobi dankai sanka no koka

Optical in situ size determination of single lanthanide-ion doped oxide nanoparticles

The oxidation conditions were investigated for obtaining a higher productivity in the production of high strength carbon fiber from polyacrylonitrile (PAN). The effect of incorporation of 2 % comonomer such as methyl acrylate (MA), acrylate containing carboxylate (SA), acrylamide (AAm), and hydroxyethyl acrylate (HEA) on the oxidation conditions was also investigated. The measurement of DSC and bonded oxygen content revealed that the most effective comonomer for promoting the cyclization of nitril group and the bonding of oxygen was found to be SA, and the second best was AAm. The measurement of tensile strength of carbon fiber showed that the copolymer of SA, HEA, and MA gave a high strength fiber. It took a long time to oxidize the carbon fiber when it was oxidized at a temperature on which double layer structure was not formed. To shorten the production time, a method of combining the upper limit ...

1994-06-10

186

Morphology-controlled synthesis and novel microwave electromagnetic properties of hollow urchin-like chain Fe-doped MnO2 under 10 T high magnetic field

We show that the size of a lanthanide-ion doped nanoparticle can be accurately determined from its luminosity. The optically determined size distribution is in very good agreement with the distribution obtained from transmission electron microscopy. These data confirm that single nanoparticles are visualized in microscopy experiments. Nanoparticles as small as 13 nm are detectable with integration times of 500 ms.

2006-12-01

187

Molecules with polymerizable ligands as precursors to porous doped materials

Fe-doped MnO2 with a hollow sea urchin-like ball chain shape was first synthesized under a high magnetic field of 10 T. The formation mechanism was investigated and discussed in detail. The synthesized samples were characterized by XRD, SEM, TEM, EMPA, and vector network analysis. By doping MnO2 with Fe, the relative complex permittivity of MnO2 and its corresponding loss tangent clearly decreases, but its relative complex permeability and its corresponding loss tangent markedly increases. Moreover, the theoretically calculated values of reflection loss show that with increasing the Fe content, the as-prepared Fe-doped MnO2 exhibits good microwave absorption capability. -- Graphical Abstract: Fe-doped MnO2 with a hollow sea urchin-like ball chain shape was first synthesized in a high magnetic field of 10 T via a simple chemical process. Display Omitted Highlights: ? Fe-doped MnO2 ...

2011-05-01

188

Ferromagnetism in Mn-doped GaAs layers: Effects of laser annealing

Titanium and aluminum alkoxide derivatives with polymerizable ligands such as 2-(methacryloyloxy)ethylacetoacetate (HAAEMA), oleic acid and geraniol (HOGE) have been obtained. The various compounds have been characterized by FT-IR and NMR {sup 1}H. Copolymerization with styrene and divinylbenzene affords porous doped organic materials which have been characterized by scanning electron microscopy (SEM), elemental analysis, density measurements.

1996-12-31

189

Conductivity of doped N-carbazolyl-substituted polysilanes

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

2006-05-15

190

A real time neutron diffraction study on the reaction of AsF_5 with deuterated polyparaphenylene

A series of N-carbazolyl-substituted silane homo- and copolymers has been prepared by Wurtz coupling. Doping with iodine on these copolymer films increases the electrical conductivity to the range 10{sup -6}-10{sup -3} S cm{sup -1}. The conductivity depends strongly on the composition of the copolymer; it reaches the maximum value for N-carbazolyl-substituted silane homopolymer. The effects of carbazolyl group on conductivity and charge transport mechanisms in the polymer are discussed. (orig.)

1995-08-01

191

Thermoluminescence studies in cerium doped NaCl crystals

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

1982-01-01

192

Theoretical study on the effects of oxygen doping on the lithium ion conductive perovskite-type manganese fluoride of KxBa(1-x)/2MnF3

Cerium is known to enter substitutionally in trivalent state when doped in alkali halides. Cerium doped NaCl crystals exhibit greatly enhanced thermoluminescence output upon X-irradiation at RT, the intensity of emission being about 10 times that in undoped crystals for similar dosage of irradiation. The cerium doped crystals give upon X-irradiation a very intense glow peak at 145degC with shoulders at 120degC and 210degC. Upon partially bleaching the crystal with F-light, the peak at 120degC becomes prominent probably due to faster bleaching of the glow at 145degC. From further optical bleaching studies, it is concluded that the glow peak at around 120degC is due to cerium centres in the irradiated crystal and the 145degC peak due to F centres. This F centre emission occurs at lower temperature, compared to that in the undoped crystals where it occurs at around 180degC. The spectral emission in the Ce ...

193

British Library Electronic Table of Contents (United Kingdom)

Previously, we demonstrated that the lithium ion conduction in the perovskite-type manganese fluoride is attributed to counter cation-site vacancy mechanism. The divalent counter cation-doped KxBa(1-x)/2MnF3 was theoretically predicted as the lithium ion conductor in the perovskite-type manganese fluoride. In this study, we considered the oxygen doping for KxBa(1-x)/2MnF3 to realize the higher lithium ion conductivity. It is because lithium ion forms the stronger ionic bond with the doped oxygen anion. The hybrid-DFT calculations were performed to investigate the lithium ion conduction in the oxygen-doped KxBa(1-x)/2MnF3. The calculation results were discussed from the viewpoints of the potential energy curve, electron densities, and charge and spin densities. The effect of the lithium ion...

2009-01-01

194

Synthesis of (Bi0.5Na0.5)TiO3 (BNT) and Pr doped BNT using the soft combustion technique and its properties

British Library Electronic Table of Contents (United Kingdom)

In this work, bismuth sodium titanate (Bi0.5Na0.5)TiO3 (BNT) and praseodymium (Pr)-doped BNT were successfully produced using the soft combustion technique. The effects of Pr doping on stoichiometry, microstructure, density and dielectric properties were studied. Pure Pr-doped BNT was obtained in all samples containing 5, 10 and 20mol% Pr after calcination at 800^oC for 3h. The produced powders were then pressed into pellets and sintered at 1100^oC for 3h. The very similar ionic radii of Pr^3^+ with Bi^3^+ and Na^+ made it possible to substitute both Bi and Na. The crystallite size and grain size decreased with increasing Pr amount because Pr acted as grain growth inhibitor, both for calcined powders and for sintered pellets. Maximum density was obtained in 5mol% Pr-doped BNT, beyond which...

2011-01-01

195

Evaluation of paramagnetic species in coals with iodine doping technique; Yoso tenkaho wo mochiita sekitanchu no jojiseishu no hyoka

Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium

Electron paramagnetic resonance (EPR) of coals was considered by using iodine doping technique. Sub-bituminous coal (WA) and bituminous coal (UF) were used to observe EPR spectra using microwaves. With the UF coal, strength of the narrow component of the spectra was found constant regardless of amount of the doped iodine, wherein radicals without interaction with iodine were detected. Strength of the broad component increased with the iodine doping amount, where in deviation of {pi} electrons was detected, which have been generated as a result of interaction between aromatic rings and iodine in the coals. Spin concentration of the WA coal with low coalification degree is constant regardless of the iodine doping amount, and the interaction of the iodine with the aromatic rings was found small. The higher the coalification degree, the more the aromatic ring structure grows, and electron donor capability ...

1996-10-28

196

Aging and compatbility of TNF-doped mylar

The primary concern of this work is to study the emission characteristics of a series of chiral nematic liquid crystal lasers doped with different laser dyes (DCM, pyrromethene 580, and pyrromethene 597) at varying concentrations by weight (0.5-2 wt %) when optically pumped at 532 nm. Long-wavelength photonic band-edge laser emission is characterized in terms of threshold energy and slope efficiency. At every dye concentration investigated, the pyrromethene 597-doped lasers exhibit the highest slope efficiency (ranging from 15% to 32%) and the DCM-doped lasers the lowest (ranging from 5% to 13%). Similarly, the threshold was found to be, in general, higher for the DCM-doped laser samples in comparison to the pyrromethene-doped laser samples. These results are then compared with the spectral properties, quantum efficiencies and, where possible, fluorescence lifetimes of the dyes ...

2010-02-01

197

Friction and wear properties of glass fiber reinforced nylons against alumina ceramics in oil; Yuchu ni okeru glass sen`i kyoka nylon no alumina ceramics ni taisuru masatsu mamo tokusei

TNF-doped Mylar is a new radiation-hard dielectric that has recently been qualified as a viable substitute for Mylar in capacitors. The advantage of TNF-doped Mylar is that it satisfies both the nuclear safety and radiation hardness requirements of weapons. Mylar is not radiation-hard. Aging and compatibility studies were carried out to insure that (1) TNF does not diffuse from the film during fabrication of the capacitor or during storage; and (2) there are no compatibility problems with aluminum foil (the conductor) or Fluorinert (the secondary dielectric). Losses of TNF were barely detectable during the vacuum bakes used in fabricating capacitors or during accelerated aging tests carried out below T{sub g} (70C) over a two year period in air. In other accelerated tests, no compatibility problems were detected with aluminum or Fluorinert. TNF-doped Mylar is now being used in the MC-4109 capacitor that was called out for ...

1990-01-01

198

Multi-scale modeling of fiber and fabric reinforced cement based composites

The friction and wear properties of glass fiber reinforced composites of nylons (nylon 6, nylon 66 and nylon 46) with different crystallinities due to their molecular structures were investigated by sliding them with alumina ceramics and using a pin-on-disk friction machine. The friction coefficients of the glass fiber reinforced nylons in oil were lower and more stable than those in air from the initial stage of friction. The transfer of nylon matrix to adhere onto the alumina surface in air was so much greater than in oil that the alumina surface could not be recognized. Consequently, a different between the friction and wear properties in air and in oil was resulted. Reinforcement of nylons with glass fiber remarkably improved their friction properties in oil by its lubricating action, while the wears were rather high contrary to what was expected. This tendency was conspicuous for nylon 46 with high crystallinity. ...

1997-09-01

199

Sustainable Manufacturing System Focusing on the Natural Growth of Bamboo

With an increased use of fiber reinforced concrete in structural applications, proper characterization techniques and development of design guides are needed. This dissertation presents a multi-scale modeling approach for fiber and fabric reinforced cement-based composites. A micromechanics-based model of the yarn pullout mechanism due to the failure of the interfacial zone is presented. The effect of mechanical anchorage of transverse yarns is simulated using nonlinear spring elements. The yarn pullout mechanism was used in a meso-scale modeling approach to simulate the yarn bridging force in the crack evolution process. The tensile stress-strain response of a tension specimen that experiences distributed cracking can be simulated using a generalized finite difference approach. The stiffness degradation, tension stiffening, crack spacing evolution, and crack width characteristics of cement composites can be derived using matrix, interface and ...

2008-01-01

200

Process for the manufacture of semi-rigid, folding solar generators manufactured from several coated solar cells. Verfahren zur Herstellung eines halbstarren, faltbaren, aus mehreren bedeckten Solarzellen (Cics) hergestellten Solargenerators

Recently, sustainable materials have attracted attention because of the need to alleviate environmental problems. Bamboo, in particular, has attracted attention as a sustainable material because it has the fastest natural growth rate among various natural materials. A self-bonding fiberboard using high quality bamboo fiber extracted with a machining center has been enabled to be fabricated by hot press forming. Therefore, we propose a sustainable manufacturing system that focuses on bamboo. An environmental impact of our system was evaluated by life cycle assessment (LCA), comparing with a glass fiber reinforced plastic production. Additionally, based on the LCA result, higher efficient fiber extraction process was proposed by an application of in-situ measurement of uninformed bamboo shape with irregularity.

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201

Optical sensor for temperature measurement using bimetallic concept

This is a process for manufacturing a semi-rigid, folding solar generator manufactured from several coated solar cells (Cics), which has at least two folding parts connected together so as to turn by hinges, characterized by the following stages of the process: a) On the back of matrix subsections, in order to cover the connector, carbon fibre strips are glued on, which project over the upper or lower edge of each matrix subsection. b) The projecting ends of adjacent carbon fiber strips are connected with two carbon fibre strips. c) At least two matrix subsections are fixed in separately manufactured carbon fiber frames, and d) the carbon fiber frames, together with the matrix subsections are connected via hinges to a solar generator.

1985-10-31

202

British Library Electronic Table of Contents (United Kingdom)

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

2011-01-01

203

Monte Carlo simulations incorporating Mie calculations of light transport in tissue phantoms: Examination of photon sampling volumes for endoscopically compatible fiber optic probes

Modelling the effects of measured anode triple-phase boundary densities on the performance of micro-tubular hollow fiber SOFCs

Details of the interaction of photons with tissue phantoms are elucidated using Monte Carlo simulations. In particular, photon sampling volumes and photon pathlengths are determined for a variety of scattering and absorption parameters. The Monte Carlo simulations are specifically designed to model light delivery and collection geometries relevant to clinical applications of optical biopsy techniques. The Monte Carlo simulations assume that light is delivered and collected by two, nearly-adjacent optical fibers and take into account the numerical aperture of the fibers as well as reflectance and refraction at interfaces between different media. To determine the validity of the Monte Carlo simulations for modeling the interactions between the photons and the tissue phantom in these geometries, the simulations were compared to measurements of aqueous suspensions of polystyrene microspheres in the wavelength range 450-750 nm.

1996-04-01

204

British Library Electronic Table of Contents (United Kingdom)

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

2011-01-01

205

Light from polymers - prediction of service life

Influence of interphase morphology on adhesion and composite durability in semicrystalline polymer matrix composites

Stress chemiluminescence (SCL) is a novel technique for monitoring aging reactions of polymeric materials under stress. A special apparatus for detecting the chemiluminescence of solid polymers has been designed and built. There is a correlation between an enhanced chemiluminescence signal at low levels of applied stress and subsequent premature mechanical failure of samples of tetraglycidyl-4,4'-methylenedianiline (TGMDA) cured with 4,4'-diaminodiphenyl sulfone (DDS) the most commonly used epoxy in high performance fiber composites. Chemiluminescence data from silicone cushions is used to validate accelerated aging tests and preliminary results from Kevlar fibers are reported. The technique will be extended to other polymeric materials including fiber composites. 22 references, 7 figures, 1 table.

1984-01-01

206

Fatigue life prediction of cross-ply composite laminates

The microstructure of the interphase in semicrystalline polymer matrix composites has a dramatic influence on their mechanical properties. Studies have been performed to alter this region and to correlate various interphase morphologies with changes in fiber-matrix adhesion. A reinforced nylon 66 composite, when subjected to specific thermal histories, contains an interphase composed of transcrystallinity. This region has been altered by coating fibers with a diluent, poly(vinyl pyrrolidone), and/or adding the diluent to the matrix material in very small quantities. Interphase morphology was investigated with optical microscopy, and adhesion was measured using a modified fiber pull-out test. It was found that transcrystallinity increases the interfacial shear strength. The effect different interphase morphologies have on the durability of bulk composite samples is currently under investigation.

1996-12-31

207

Enzymatic solubilization of a pectinaceous dietary fiber fraction from potato pulp: Optimization of the fiber extraction process

To predict the fatigue life of fiber reinforced composites, fatigue process of CFRP laminates of [0 /90 ]{sub s} is investigated and the influence of damages occurring at fiber, matrix and fiber/matrix interface on the various critical strengths and the relationship between residual critical strength and failure are discussed. As a result, it was shown that fatigue strength (i.e. fatigue life) consisted of residual critical strength and stresses occurring at each layer (0 and 90 layers) and interlayer. Moreover, the fatigue failure occurred because the residual critical strength of each layer and interlayer decreased with dependence of their microdamage densities, so that the fatigue life can be predicted by evaluating microdamage behavior in fatigue process. (orig.) 14 refs.

1997-11-15

208

British Library Electronic Table of Contents (United Kingdom)

Upgrading of potato pulp, a byproduct stream from industrial manufacture of potato starch, is important for the continued economic competitiveness of the potato starch industry. The major part of potato pulp consists of the tuber plant cell wall material which is particularly rich in galactan branched rhamnogalacturonan I type pectin. In the work reported here, the release of high-molecular weight pectinaceous dietary fiber polysaccharides from starch free potato pulp was accomplished by use of a multicomponent pectinase preparation from Aspergillus aculeatus (Viscozyme L). The enzyme reaction conditions for the solubilization were optimized via a surface response design to be addition of 0.27% Viscozyme L by weight of potato pulp substrate dry matter, 1h treatment at pH 3.5, 62.5degreeC. ...

2009-01-01

209

Effects of carbon fiber surface treatment on the friction and wear behavior of 2D woven carbon fabric/phenolic composites

British Library Electronic Table of Contents (United Kingdom)

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

2009-01-01

210

Effect of carbon fibers surface treatment on tribological performance of polyurethane (PU) composite coating

British Library Electronic Table of Contents (United Kingdom)

The carbon fibers (CF) were pre-treated in two different ways: no pre-treatment, and activation in HNO3 plus application of toluene-2,4-diisocyanate (TDI). Carbon fibers have been introduced into polyurethane (PU) composite coatings. The tribological behaviors of the polyurethane composite coating filled with CF or TDI-modified CF (TDI-CF) were studied using a ring-on-block wear tester under dry sliding, and the worn surfaces of the filled PU coatings and transfer films formed on the surface of the counterpart ring sliding against the PU coating were investigated by SEM and optical microscope (OM), respectively. Owing to the effective improvement of the interfacial adhesion between the CF and polyurethane matrix, compared with the cases of untreated CF, the employment of low content TDI-CF...

2008-01-01

211

Characterization of treated date palm tree fiber as composite reinforcement

British Library Electronic Table of Contents (United Kingdom)

Recently, great interest was paid to new technologies dealing with environmental aspect. Preservation of natural resources such as natural fibers forced the composite industry to search and examine "eco-friendly" components. Studies to find alternative reinforcements and resin systems that are environmentally friendly while providing the same performance as their synthetic counterparts are in continuous progress. The aim of this study is to investigate effect of different treatment process on the data palm fiber (DPF). Raw DPF underwent different surface modification methods such as alkali treatment with concentrations 0.5%, 1%, 1.5%, 2.5% and 5%, and acid treatment with 0.3, 0.9 and 1.6N. All treatments were performed at 100degreeC for 1h. The surface morphology, thermal gravimetry analys...

2009-01-01

212

Angiopoietin Balance in Septic Shock Patients With Acute Lung Injury: Effect of Direct Hemoperfusion With Polymyxin B-Immobilized Fiber

British Library Electronic Table of Contents (United Kingdom)

Abstract Acute lung injury (ALI) in sepsis is characterized by an increase in microvascular permeability, resulting in pulmonary edema. Several studies have suggested that angiopoietin-1 and -2 play a contributory role in the pathogenesis of ALI. Polymyxin B-immobilized fiber column hemoperfusion is effective for sepsis-induced ALI. We investigated the angiopoietin levels before and after direct hemoperfusion with polymyxin B-immobilized fiber column (PMX) therapy. Enzyme-linked immunoassay was used to measure the serum angiopoietin-1 and -2 levels in 25 patients with septic shock treated with PMX. Eleven of the 25 patients were diagnosed with ALI. There was a significant positive correlation between the angiopoietin-1 level and the PaO2/FiO2 ratio, but there was a significant inverse corr...

2011-01-01

213

Investigation of lauric acid dopant as a novel carbon source in MgB{sub 2} wire

Effects of initial microstructure and helium production on radiation hardening in F82H Steels

We fabricated lauric acid (LA) doped MgB{sub 2} wires and investigated the effects of the LA doping. For the fabrication of the LA-doped MgB{sub 2} wires, B powder was mixed with LA at 0-5 wt.% of the total amount of MgB{sub 2} using an organic solvent, dried, and then the LA-treated B and Mg powders were mixed stoichiometrically. The powder mixture was loaded into an Fe tube and the assemblage was drawn and sintered at 900 deg. C for 3 h under an argon atmosphere. We observed that the LA doping induced the substitution of C for the B sites in MgB{sub 2} and that the actual content of C increased monotonically with increasing LA doping level. The LA-doped MgB{sub 2} wires exhibited a lower critical temperature (T{sub c}), but better critical current density (J{sub c}) behavior in a high magnetic field: the 5 wt.% LA-doped sample had a J{sub ...

2010-11-01

214

Dielectric dispersion study of Mn-doped PLZT (8/65/35)

Full text of publication follows: Fission neutron irradiation to steels doped with isotope boron-10 is frequently conducted to study effects of the helium production on mechanical properties. The intrinsic mechanical properties of F82H steels could have been changed due to the boron doping. Recently, we reported that co-doping with boron and nitrogen to F82H (F82H+B+N) improved the mechanical properties of F82H doped only with boron. The mechanical properties of F82H+B+N are successfully comparable with the non-doped F82H before irradiation. In order to evaluate the effects of initial microstructure and helium production on radiation hardening, F82H and F82H+B+N were irradiate d Specimens used in this study were standard F82H martensitic steels, F82H steels doped with 60 mass ppm 10B and 200 ppm N (F82H+10B+N) and F82H steels doped with 60 ...

2007-12-10

215

Visible light photocatalytic activity and Photoelectrochemical property of Fe-doped TiO2 hollow spheres by sol?gel method

Mn-modified Pb0.92La0.08(Zr0.65Ti0.35)O3 (PLZT) was prepared chemically by a coprecipitate method using their respective nitrate salts and isopropoxides. Differential thermal analysis (DTA) and X-ray analysis clearly show the formation of PLZT single rhombohedral phase for samples calcined beyond 750 C. Uniform grain distribution was observed from scanning electron microscopic (SEM) studies and grain size was found to increase with Mn doping up to x=0.08 and then decreased. Dielectric measurement shows the decrease in peak transition temperature (TC) with Mn doping up to x=0.12 and then increase along with a sharp rise in dielectric maxima. A diffuse dielectric dispersion is observed in all the compositions. A detailed dispersion study was carried out using the Vogel-Fulcher empirical relation, a universal relaxation law and the Havriliak-Negami function. The Vogel-Fulcher relation fitting parameters of activation energy and freezing ...

2009-07-01

216

British Library Electronic Table of Contents (United Kingdom)

Fe-doped TiO2 hollow spheres (Fe-THs) were synthesized by sol?gel process using carbon spheres as templates. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV?vis diffuse reflectance spectrum (DRS), N2 adsorption?desorption isotherms, Electron paramagnetic resonance (EPR) spectroscopy and Photoluminescence emission spectroscopy (PL). UV?vis spectra showed that Fe3+ doping could extend the absorption edge to the visible region. EPR spectra showed that Fe3+ was incorporated into the crystal lattice of TiO2, which could inhibit the recombination of photo-induced electron?hole pairs and improve the photocatalytic activity. The photocatalytic activities of the prepared samples were evaluated for the degradation of dye Reactive Brillia...

2011-01-01

217

Thermoluminescence studies in lead doped KCl and KBr crystals

Synthesis and characterization of undoped and TM (Co, Mn) doped ZnO nanoparticles

Lead is known to enter substitutionally in divalent state when doped in alkali halides. When irradiated at room temperature these lead centers (Pb"+"+) act as traps for electrons knocked off from the halogen ions and become Pb"+ and Pb"0 (for large doses of irradiation). These changes could be followed in the optical absorption studies. These lead-doped crystals after X-ray irradiation yield a thermoluminescence output smaller than that observed in 'pure' crystals. However, two new glow peaks are observed in additions to those due to F-centers. In KCl : Pb and Kbr : Pb crystals part of the F-center glow preceds the new glow peaks. The new peaks are attributed to the Pb"+ and Pb"0 centers. The glow peak temperatures and trap depths for these peaks an obtained by total-curve fitting method are reported. (author).

1975-02-12

218

British Library Electronic Table of Contents (United Kingdom)

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

2011-01-01

219

Silicon oxide conductivity of hydrogen ion implanted polysilicon thin film transistors

Silicon oxide conductivity of hydrogen ion implanted polysilicon thin film transistors

The influence of hydrogen ion implantation into the channel polysilicon of polysilicon thin film transistors on gate oxide conductivity has been investigated. Data for effective tunnelling barriers at the gate oxide/channel polysilicon interface are presented. A value of 1.2eV for samples with boron doped channel polysilicon is calculated. For hydrogenated boron doped samples tunnelling barriers higher than 2.1 eV are obtained. The tunnelling barriers for phosphorus doped samples are impurity concentration dependent and decrease with increasing phosphorus concentration in the range 3 x 10{sup 17} to 3 x 10{sup 19} cm{sup -3}. (Author).

1996-10-01

220

Screen-printed Emitter-Wrap-Through solar cell with single step side selective emitter with 18.8% efficiency

The influence of hydrogen ion implantation into the channel polysilicon of polysilicon thin film transistors on gate oxide conductivity has been investigated. Data for effective tunnelling barriers at the gate oxide/channel polysilicon interface are presented. A value of 1.2eV for samples with boron doped channel polysilicon is calculated. For hydrogenated boron doped samples tunnelling barriers higher than 2.1 eV are obtained. The tunnelling barriers for phosphorus doped samples are impurity concentration dependent and decrease with increasing phosphorus concentration in the range 3 x 10"1"7 to 3 x 10"1"9 cm"-"3. (Author).

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221

British Library Electronic Table of Contents (United Kingdom)

Abstract A fabrication process for Emitter-Wrap-Through solar cells on monocrystalline material with high quality gap passivation by wet thermal silicon dioxide is investigated. Masking and structuring steps are performed by screen-printing technology. Via-holes are created by an industrially applicable high-speed laser drilling process. The cell structure features a selective emitter structure fabricated in a single high temperature step: a highly doped emitter at the via-holes and the rear side, allowing for a low via-hole resistivity as well as a low resistivity contact to screen-printed pastes, and a moderately doped front side emitter exhibiting high quantum efficiency in the low wavelength range. Therefore a novel approach is applied depositing either doped or undoped PECVD silicon d...

2011-01-01

222

Luminescence spectroscopy of Er3+-doped and Er3+, Yb3+-codoped LaPO4 single crystals

Influence of laser power on the properties of laser doped solar cells

LaPO4 single crystals lightly doped with Er3+, and codoped with Er3+ and Yb3+ have been grown by spontaneous nucleation in a lead phosphate flux. Absorption and luminescence spectra have been measured in the visible and near-IR regions and the excited state dynamics has been studied upon pulsed laser excitation. The obtained results have allowed the evaluation of the effective emission cross-sections around 1.5 ?m, that have been found to be similar to important oxide laser crystals doped with Er3+. Efficient visible upconversion has been observed upon excitation at 980 nm in the codoped crystals. This behaviour is attributed to Yb3+-Er3+ energy transfer processes.

2009-05-01

223

British Library Electronic Table of Contents (United Kingdom)

In recent years, increased attention has been focused on the use of lasers in different fabrication steps of solar cells, in particular laser doping to form emitter and/or selective emitter. In this method the laser energy is used to melt silicon, allowing the diffusion of dopant atoms to occur in the liquid phase. The main advantage of this method is the localised nature of the laser beam, which melts and diffuses a limited area without heating the bulk, therefore reducing the possible degradation associated with high temperature processes. At the University of New South Wales a novel laser doping method was developed, which combines the formation of the selective emitter with a self-aligned metallisation pattern. Despite achieving high efficiencies, concerns arose regarding the adhesion ...

2011-01-01

224

Impedance spectroscopy study with H-doped ammonium uranylphosphate self supported membranes

Effects of manganese doping on properties of sol-gel derived biphasic calcium phosphate ceramics

Equivalent circuit and electrical parameters for H-doped NH{sub 4}UO{sub 2}PO{sub 4}.3H{sub 2}O self supported membranes have been determined by impedance spectroscopy. The measurements were carried out with a dry membrane, at different temperatures, and a wet membrane in contact with different electrolyte solutions. Resistance values for the dry membrane decrease with temperature increase, which agrees with the weak protonic character of the H-doped ammonium uranylphosphate. On the other hand, differences in the electrical parameters, depending on the electrolyte considered were also obtained and are attributed to different conduction mechanisms. (Author).

1995-01-01

225

British Library Electronic Table of Contents (United Kingdom)

We have investigated the effect of manganese (Mn) doping on properties of nanosized biphasic calcium phosphate powders and their dense bodies. Manganese levels of 0.6, 1.3, 1.9, 4.3, 7.0 and 11.9at.% were successfully incorporated into biphasic calcium phosphate via a sol-gel route. The prepared powders were calcined at temperatures of 500-1200^oC. The X-ray diffraction analysis revealed that a mix phase comprising of hydroxyapatite and @b-tricalcium phosphate were present, however the content of each phases in the structure was affected by the Mn content. The studies found that the largest portion of @b-tricalcium phosphate was detected at 4.3at.% Mn doping. The incorporation of Mn has also greatly increased the crystallinity of the biphasic calcium phosphate powder due to progressive den...

2011-01-01

226

Application of neutron transmutation doping method to initially p-type silicon material

Application of neutron transmutation doping method to initially p-type silicon material

The neutron transmutation doping (NTD) method was applied to the initially p-type silicon in order to extend the NTD applications at HANARO. The relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material was investigated. The proportional constant between the neutron fluence and the resistivity was determined to be 2.3473x10{sup 19} n {omega} cm{sup -1}. The deviation of the final resistivity from the target for almost all the irradiation results of the initially p-type silicon ingots was at a range from -5% to 2%. In addition, the burn-up effect of the boron impurities, the residual {sup 32}P activity and the effect of the compensation characteristics for the initially p-type silicon were studied. Conclusively, the practical methodology to perform the neutron transmutation doping of the initially p-type silicon ingot was established.

2009-07-15

227

A novel electrogenerated chemiluminescence sensor for pyrogallol with core-shell luminol-doped silica nanoparticles modified electrode by the self-assembled technique

The neutron transmutation doping (NTD) method was applied to the initially p-type silicon in order to extend the NTD applications at HANARO. The relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material was investigated. The proportional constant between the neutron fluence and the resistivity was determined to be 2.3473x1019 n ? cm-1. The deviation of the final resistivity from the target for almost all the irradiation results of the initially p-type silicon ingots was at a range from -5% to 2%. In addition, the burn-up effect of the boron impurities, the residual 32P activity and the effect of the compensation characteristics for the initially p-type silicon were studied. Conclusively, the practical methodology to perform the neutron transmutation doping of the initially p-type silicon ingot was established.

2008-05-12

228

British Library Electronic Table of Contents (United Kingdom)

The core-shell luminol-doped SiO2 nanoparticles were synthesized and immobilized on the surface of chitosan film coating graphite electrode by the self-assembled technique. Then, a novel electrogenerated chemiluminescence (ECL) sensor for pyrogallol was developed based on its ECL enhancing effect for the core-shell luminol-doped silica nanoparticles. The ECL analytical performances and the sensing mechanism of this ECL sensor for pyrogallol were investigated in detail. The corresponding results showed that: compared with the conventional ECL reaction procedures by luminol ECL reaction system, the electrochemical (EC) reaction of pyrogallol and its subsequent chemiluminescence (CL) reaction occurred in the different spatial region whilst offering a high efficiency to couple the EC with the ...

2006-01-01

229

Wear behavior on advanced structural ceramics: #alpha#-sialon matrix reinforced with #beta#-sialon fibers

Transversal Stiffness and Young's Modulus of Single Fibers from Rat Soleus Muscle Probed by Atomic Force Microscopy

For several decades, ceramic matrix composite have been attracted attention in advanced structural and tribological applications. Advanced structural ceramics are presently used in diverse tribological applications such as tips for ballpoint pens, precision instrument bearings and cutting tools inserts. Design and selection of ceramics for these applications require reliable data on the effects of temperature, load and environment on the tribological behavior of these ceramics. In the present work, #alpha#-sialon matrix composites reinforced with different amounts of #beta#-sialon fibers were produced with the aim of improving their toughness to increase the industrial applications. The wear properties of #alpha#-sialon matrix composites were evaluated by carried out wear tests using a pin-on-disk tribometer under dry conditions. The #alpha#-sialon matrix composites were manufactured by slip casting and sintered by uniaxial hot pressing. Scanning electron ...

2005-08-01

230

THE STRUCTURE AND FUNCTION OF CENTRIOLES AND THEIR SATELLITES IN THE JELLYFISH PHIALIDIUM GREGARIUM

AbstractThe structural integrity of striated muscle is determined by extra-sarcomere cytoskeleton that includes structures that connect the Z-disks and M-bands of a sarcomere to sarcomeres...Full Text Available

2010-02-03

231

Study of nuclear materials by neutron scattering.

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

1964-06-01

232

Receptive Field Remodeling Induced by Skin Stimulation in Cerebellar Neurons in vivo

Following studies on fiber and sheet texture of hexagonal crystal system in 1988, work has been extended to tube texture. Using the zircaloy-4 fuel cladding of Wolsung-type reactor as specimen, six pole figures for different crystallographic planes were m...

1990-01-01

233

Pre-irradiation technique for processing of oil palm fruit bunch fibers - polypropylene composites

The receptive field of a neuron reflects its function. For example, for parallel fiber (PF) inputs in C3 zone the cerebellar cortex, the excitatory and inhibitory receptive fields of a Purkinje cell...Full Text Available

234

Potentials for composites from agro-based fibers

Researches on oil palm empty fruit bunch (EFB) fibers and thermoplastic composites have been carried out by many workers in the last decade. The main focus was to enhance the properties of the resultant composites in view of the incompatibility of the two components. Thus, efforts have been made to enhance their properties by using coupling agents, treating the fibers and modifying the matrices. In this study, the effects of electron beam (EB) irradiation and some reactive additives (RAs) on the mechanical properties of EFB-PP (polypropylene) composites were evaluated. Different modes of irradiation were investigated. Mono, di and tri functional of monomers of RAs were used. irradiating PP alone, compared to irradiating the EFB fibers or irradiating both components, gave optimum properties for EFB-PP composites. Further, improvements of the properties of the composites were achieved with the addition of RAs with TMPTA ...

2002-06-25

235

Opto-acoustic recanilization delivery system

A composite is any combination of two or more resources held together by some type of mastic or matrix. This report will describe several different types of composites with regard to thermoplasticization, improved mechanical properties, and stiffness.

1995-12-01

236

Microstructure and mechanical properties of quasi-carbon fibers and their polyacrylonitrile matrix composites

Fiber delivered laser pulses emulsify thrombus by mechanical stresses that include a combination of pressure, tension and shear stress. Laser radiation is delivered to the locality of a thrombus and the radiation is absorbed by blood, blood dot, or other present materials. The combination of a leading pressure wave and subsequent vapor bubble cause efficient, emulsification of thrombus. Operating the laser in a low average power mode alleviates potential thermal complications. The laser is operated in a high repetition rate mode to take advantage of ultrasound frequency effects of thrombus dissolution as well as to decrease the total procedure time. Specific parameter ranges for operation are described. The device includes optical fibers surrounding a lumen intended for flow of a cooling agent. The fibers may be arranged concentrically around the lumen to deliver radiation and heat over as large an area as possible. An ...

2002-01-01

237

Maryland mill will recycle wastepaper, reclaim water

Quasi-carbon fibers (QCFs) were prepared from Polyacrylonitrile (PAN) precursor by pyrolysis in the temperature range from 400{degrees}C to 950{degrees}C. The QCF-reinforced composites were fabricated by impregnating the QCFs with the PAN resin. The microstructural changes of both QCFs and their composites were characterized by the X-ray diffraction method. The stacking size and the crystallinity of the QCFs increased with the increasing heat treatment temperature (HTT). The crystallinity of the PAN matrix in a composite was also affected by various QCFs. DSC data indicated that thermal reaction mechanism of the composite could be altered due to the interaction between the fiber and the matrix. DMTA studies showed that good adhesion existed at the interface of the QCF-reinforced composites containing lower HTT fibers. The modulus magnitudes of QCFs and their composites increased with the QCF pyrolysis temperature. Although ...

1994-12-31

238

Intrinsic plasticity complements LTP in parallel fiber input gain control in cerebellar Purkinje cells

A $200 million paper mill being built in Hagerstown, Md., is expected to produce 150,000 bone-dry short tons per year of de-inked, market-grade pulp for writing and printing paper. The 1st Urban Fibers facility, the largest capital project in Hagerstown's history, is slated for completion in the spring. Landegger Recycled Fiber Corp. will operate and maintain the 200,000-square-foot recycling mill and 60,000-square-foot water reclamation plant. The wastepaper recycling mill plans to minimize waste and pollution by: reclaiming 635 tons per day of 100 percent post-consumer mixed office waste from the solid waste stream; saving more than 16 million cubic feet of landfill area per year; conserving the fiber equivalent of 6,700 trees per day; using no chlorine; saving about 2,000 gallons of water and 4,000 kilowatt hours of electricity per ton of throughput, compared to virgin fiber mills; reusing ...

1995-02-01

239

Intraoral Repair of All Ceramic Fixed Partial Denture Utilizing Preimpregnated Fiber Reinforced Composite

Synaptic gain control and information storage in neural networks are mediated by alterations in synaptic transmission, such as in long-term potentiation (LTP). Here, we show using both in...Full Text Available

2010-10-13

240

Integration of fiber coupled high-Q silicon nitride microdisks with magnetostatic atom chips

All ceramic fixed partial dentures (FPD)s exhibit enhanced biocompatibility and esthetics as compared to metal-ceramic restorations. However, framework fractures are frequently reported especially when...Full Text Available

2008-01-01

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241

Intact A?-fibers up-regulate TRPA1 and contribute to cold hypersensitivity in neuropathic rats

Micron scale silicon nitride (SiNx) microdisk optical resonators fabricated on a silicon wafer are demonstrated with Q = 3.6 x 10^6 (finesse = 5 x 10^4) and an effective mode volume of 15 (\\lambda / n)^3 at wavelengths \\lambda ~ 852 nm resonant with the D2 transition manifold of cesium. A dilute hydrofluoric wet etch is shown to provide sensitive tuning of the microdisk optical resonances, and robust mounting of a fiber taper provides efficient fiber optic coupling to the SiNx microdisk cavities while allowing unfettered optical access for laser cooling and trapping of atoms. Initial measurement of a hybrid atom-cavity chip indicates that cesium adsorption on the surface of the SiNx microdisks results in significant red-detuning of the disk resonances. A technique for parallel integration of multiple (10) microdisks with a single optical fiber taper is also demonstrated.

2006-01-01

242

High power nickel - cadmium cells with fiber electrodes (FNC)

Mechanisms underlying cold hypersensitivity in neuropathic states are unclear. Recent data indicate both TRPM8 and TRPA1 play a role. In relation to TRPA1, there are reported increases in mRNA....Full Text Available

2008-06-26

243

Health hazards in the production and processing of some fibers, resins, and plastics in Bulgaria.

Nickel cadmium batteries differ greatly in their mechanical design and construction of the electrodes. Using available electrode constructions, batteries are designed which meet the requirements of specific applications and offer optimum performance. Pocket- and tubular cells are basically developed with the technology of the year 1895. Since then some improvements with todays technology have been made. The sintered cells use the technology of the 1930's and they are still limited to high power application. With this knowledge and the technology of today the fiber-structured nickel electrode (FNC) was developed at DAUG laboratory, a subsidiary company of Mercedes-Benz and Volkswagen. After ten years of experience in light weight prototype batteries for electric vehicles (1-2), the system was brought into production by a new company, DAUG-HOPPECKE. Characteristics of fiber electrodes: thickness and size can be easily changed; pure active ...

244

Functional pools of oxidative and glycolytic fibers in human muscle observed by 31P magnetic resonance spectroscopy during exercise.

Results of the toxicological studies of working conditions, general and professional morbidity, and complex examinations carried out on workers engaged in the production of polyamides, polyacrylonitrile...Full Text Available

1976-10-01

245

Fourier-Domain Optical Coherence Tomography and Adaptive Optics Reveal Nerve Fiber Layer Loss and Photoreceptor Changes in a Patient With Optic Nerve Drusen

Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative...Full Text Available

1987-12-01

246

Force enhancement without changes in cross-bridge turnover kinetics: the effect of EMD 57033.

BackgroundNew technology allows more precise definition of structural alterations of all retinal layers although it has not been used previously in cases of optic...Full Text Available

2008-06-01

247

Effects of Manufacturing Defects and Scaling on Glass Fiber Composite Sandwich Panels in General Aviation Aircraft Structures.

The thiadiazinon derivative EMD 57033 has been found previously in cardiac muscle to increase isometric force generation without a proportional increase in fiber ATPase, thus causing a reduction in...Full Text Available

1997-01-01

248

Effects of Cycling Temperatures on Fiber Metabolism in Cultured Cotton Ovules ¹

This report documents the collaborative effort between the United States and Canada to investigate the impact of process-induced defects on strength and stiffness under static and fatigue loading and for low-cost composite aircraft structures, in particul...

2009-01-01

249

Effect of nutrition conditions and 2M-4Kh herbicide on utilization of N"1"5-labelled fertilizer nitrogen by fiber-flax

The effects of temperature on rates of cellulose synthesis, respiration, and long-term glucose uptake were investigated using cultured cotton ovules (Gossypium hirsutum L. cv Acala...Full Text Available

1992-10-01

250

Dendritic Signals Command Firing Dynamics in a Mathematical Model of Cerebellar Purkinje Cells

Russian (1972). USSR Bagaev, VB Abueva, AA (no.188) p. 137-143.

251

Delineation of the Middle Longitudinal Fascicle in Humans: A Quantitative, In Vivo, DT-MRI Study

AbstractDendrites of cerebellar Purkinje cells (PCs) respond to brief excitations from parallel fibers with lasting plateau depolarizations. It is unknown whether these plateaus are local...Full Text Available

2010-07-21

252

Comparative Evaluation of Nanofibrous Scaffolding for Bone Regeneration in Critical-Size Calvarial Defects

Experimental and imaging studies in monkeys have outlined various long association fiber bundles within the temporoparietal region. In the present study the trajectory of the middle longitudinal fascicle...Full Text Available

2009-04-01

253

Combustion Mechanisms of 25MM Combustible Cartridge.

In a previous study we found that nanofibrous poly(l-lactic acid) (PLLA) scaffolds mimicking collagen fibers in size were superior to solid-walled scaffolds in promoting osteoblast differentiation...Full Text Available

2009-08-01

254

Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and characterisation of its blend with oil palm empty fruit bunch fibers

The structural features of 25mm combustible cartridge cases, manufactured for this program and having nitrocellulose/resin/fiber ratios of 85/10/5, 80/15/5, 75/20/5 and 75/10/15, were characterized through permeability measurements, respectively, about 10...

1973-01-01

255

British Library Electronic Table of Contents (United Kingdom)

Poly(3-hydroxybutyrate-co-38mol%-3-hydroxyvalerate) [P(3HB-co-38mol%-3HV)] was produced by Cupriavidus sp. USMAA2-4 in the presence of oleic acid and 1-pentanol. Due to enormous production of empty fruit bunch (EFB) in the oil palm plantation and high production cost of P(3HB-co-3HV), oil palm EFB fibers were used for biocomposites preparation. In this study, maleic anhydride (MA) and benzoyl peroxide (DBPO) were used to improve the miscibility between P(3HB-co-3HV) and EFB fibers. Introduction of MA into P(3HB-co-3HV) backbone reduced the molecular weight and improved the thermal stability of P(3HB-co-3HV). Thermal stability of P(3HB-co-3HV)/EFB composites was shown to be comparable to that of commercial packaging product. Composites with 35% EFB fibers content have the highest tensile st...

2011-01-01

256

Antibacterial Colorants: Characterization of Prodiginines and Their Applications on Textile Materials

Analysis of trigeminal nerve disorders after oral and maxillofacial intervention

A strain of Vibrio sp. isolated from marine sediments produced large quantities of bright red pigments that could be used to dye many fibers including wool, nylon, acrylics,...Full Text Available

2008-05-01

257

Ammonia Fiber Expansion (AFEX) Pretreatment, Enzymatic Hydrolysis, and Fermentation on Empty Palm Fruit Bunch Fiber (EPFBF) for Cellulosic Ethanol Production

BackgroundQuantitative sensory testing (QST) is applied to evaluate somatosensory nerve fiber function in the spinal system. This study uses QST in patients with sensory dysfunctions...Full Text Available

258

British Library Electronic Table of Contents (United Kingdom)

Empty palm fruit bunch fiber (EPFBF), a readily available cellulosic biomass from palm processing facilities, is investigated as a potential carbohydrate source for cellulosic ethanol production. This feedstock was pretreated using ammonia fiber expansion (AFEX) and enzymatically hydrolyzed. The best tested AFEX conditions were at 135??C, 45?min retention time, water to dry biomass loading of 1:1 (weight ratio), and ammonia to dry biomass loading of 1:1 (weight ratio). The particle size of the pretreated biomass was reduced post-AFEX. The optimized enzyme formulation consists of Accellerase (84??L/g biomass), Multifect Xylanase (31??L/g biomass), and Multifect Pectinase (24??L/g biomass). This mixture achieved close to 90% of the total maximum yield within 72?h of enzymatic hydrolysis. Fer...

2010-01-01

259

A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

A protocol for the production of recombinant spider silk-like proteins for artificial fiber spinning

The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. Supported by National Natural Science ...

2008-05-01

260

A high-speed network for cardiac image review.

The extreme strength and elasticity of spider silks originate from the modular nature of their repetitive proteins. To exploit such materials and mimic spider silks, comprehensive strategies...Full Text Available

2009-01-01

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261

Radio-frequency and microwave load comprising a carbon-bonded carbon fiber composite

A high-speed fiber-based network for the transmission and display of digitized full-motion cardiac images has been developed. Based on Asynchronous Transfer Mode (ATM), the network is scaleable, meaning...Full Text Available

1994-01-01

262

Nondestructive Technique Survey for Assessing Integrity of Composite Firing Vessel

A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.

1998-01-01

263

In-situ polymerization of vinyl pyrrolidinone on nylon 66 by gamma radiation

The repeated use and limited lifetime of a composite tiring vessel compel a need to survey techniques for monitoring the structural integrity of the vessel in order to determine when it should be retired. Various nondestructive techniques were researched and evaluated based on their applicability to the vessel. The methods were visual inspection, liquid penetrant testing, magnetic particle testing, surface mounted strain gauges, thermal inspection, acoustic emission, ultrasonic testing, radiography, eddy current testing, and embedded fiber optic sensors. It was determined that embedded fiber optic sensor is the most promising technique due to their ability to be embedded within layers of composites and their immunity to electromagnetic interference.

2000-08-01

264

Fundamental study on CO{sub 2} removal from the flue gas of thermal power plant by hollow-fiber gas-liquid contactor

The polymerization of vinyl pyrrolidinone on nylon 66, with the assistance of aqueous phenol and formic acid, was investigated by mutual and post irradiation procedures. Both solvents were found to greatly facilitate the polymerization with the post irradiation procedure, whereas neither presented any advantage with the mutual irradiation procedure. Tensile properties of the modified fibers were affected in similar ways by both the irradiation procedures and solvents in that the only notable changes were the somewhat higher extensions at yield and at break. The moisture regain values of the treated yarns and fabrics were increased up to three-fold. Surface morphology of the modified fibers was revealed by SEM.

1984-10-01

265

Chemiluminescence of polymers: applications to weapons materials

Microporous membranes are suitable for the CO{sub 2}-MEA (monoethanolamine) system because the overall mass transfer coefficient K of the membrane is approximately 10 times larger than that of composite membranes consisting of microporous membranes and homogeneous membranes. The overall volumetric mass transfer coefficient K{center_dot} of the hollow-fiber contact is more than 5 times larger than that of a conventional packed bed, which suggests that adorption using the present method has the advantage of making the absorption more compact. 8 refs., 7 figs., 4 tabs.

1994-12-31

266

Carbon fiber/epoxy matrix composite springs as self-centering supports: manufacture and evaluation

An apparatus was designed and built for the purpose of exposing samples of solid polymers to varying temperatures, atmospheres and stress levels while quantitatively recording the resulting chemiluminescence. Preliminary data were acquired with this apparatus that show a correlation between an enhanced chemiluminescence signal at a low level of applied stress and a decrease in tensile strength for the most commonly used epoxy resin in high performance fiber composites, TGMDA DDS. The studies with cellular silicone cushions (which are used to accommodate thermal expansion and contraction) have defined the temperature regimes in which accelerated aging tests are valid for extrapolation to ambient temperature. Preliminary data on Kevlar fibers is also discussed.

1984-06-01

267

Stable p-channel polysilicon thin film transistors fabricated by laser doping technique

A variety of engineering and experimental applications require primary support structures which are self-centering. High mechanical strength, low-density, carbon fiber/epoxy matrix composite springs are used in unique planar, cylindrical, conical, and spherical configurations to self-center components. The sinusoidal and triangular-shaped composite springs are readily manufactured and assembled into component hardware. Design considerations, flexural strength properties, load bearing and centering data plus procedures for the manufacture of composite springs are presented.

1984-01-01

268

Stable p-channel polysilicon thin film transistors fabricated by laser doping technique

In this work we present the electrical characterization of non self-aligned p-channel thin film transistors fabricated by using laser doping technique for source/drain contact formation and gate oxide deposited at room temperature by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapour Deposition. These techniques are suitable for a very low temperature process for TFT fabrication. The output characteristics show a current increase at high drain voltage ('kink' effect) rather moderate, if compared to self aligned polysilicon TFTs, probably due to the gradual doping profile induced by laser doping process. After bias stress at low gate voltage and high drain voltage condition a strong reduction of kink current has been observed in the output characteristics at high drain voltage, whereas minor changes has been observed in the transfer characteristics. This behaviour is similar to what observed in ...

2005-09-01

269

Solid state and materials research: metal-semiconductor interactions

In this work we present the electrical characterization of non self-aligned p-channel thin film transistors fabricated by using laser doping technique for source/drain contact formation and gate oxide deposited at room temperature by Electron Cyclotron Resonance Plasma Enhanced Chemical Vapour Deposition. These techniques are suitable for a very low temperature process for TFT fabrication. The output characteristics show a current increase at high drain voltage ('kink' effect) rather moderate, if compared to self aligned polysilicon TFTs, probably due to the gradual doping profile induced by laser doping process. After bias stress at low gate voltage and high drain voltage condition a strong reduction of kink current has been observed in the output characteristics at high drain voltage, whereas minor changes has been observed in the transfer characteristics. This behaviour is similar to what observed in n-channel Gate ...

2005-09-01

270

Self-organization of nickel atoms in silicon

This section of the report is concerned with the study of the metallisation, oxidation and doping of materials which are of importance to the micro-electronics industry. The Van de Graaff accelerator and radioactive tracers are used for studying surface and sub-surface behaviour of these materials.

271

British Library Electronic Table of Contents (United Kingdom)

We present experimental evidence for self-organization of nickel microparticles in silicon under certain thermodynamic conditions of nickel diffusion doping. The concentration and distribution of the microparticles in silicon are very uniform. Additional anneals lead to self-ordering of the impurity microparticles.

2011-01-01

272

Preparation of nanostructure Ni doped CdO thin films by sol gel spin coating method

British Library Electronic Table of Contents (United Kingdom)

The nanostructure Ni-doped CdO films have been prepared by sol gel spin coating method. Atomic force microscopy results indicate that the CdO films are formed from the nanoparticles and the grain size is changed with nickel content. X-ray diffraction patterns of the films indicate that the undoped and Ni-doped CdO films have polycrystalline structure with a cubic sodium chloride structure, showing two main characteristic peaks assigned to the (111) and (200) planes. The optical band gap values of undoped and Ni-doped CdO films were determined by optical absorption method. The Eg values of the CdO films were found to be in the range of 2.26?2.60?eV. The Eg values of the CdO films increase with the content of Ni dopant (up to 6% Ni). It is evaluated that the optical band gap and grain size o...

2011-01-01

273

Preparation and characterization of Co-doped BaTiO{sub 3} nanosized powders and ceramics

Effect of dysprosium doping on the optical properties of SrS:Dy,Cl phosphor

The Co-doped BaTiO{sub 3} nanosized powders and ceramics were prepared via the sol-gel process. The powders and ceramics were characterized by methods of XRD, SEM and TEM. The dielectric properties of the ceramics were also determined by these methods. The influence of sintering temperature, sintering time and Co concentration on the microstructure and dielectric properties was discussed. The results revealed that the powders were in nanometer scale (30-50 nm) and were mainly composed of cubic BaTiO{sub 3} phase and small amount of BaCO{sub 3}. After sintering, both the cubic BaTiO{sub 3} and BaCO{sub 3} were transformed into tetrahedron BaTiO{sub 3}. The sintering temperatures of the Co-doped BaTiO{sub 3} ceramics decreased (about 100 deg. C) and the Curie temperatures of the ceramics were then moved to lower temperature. In addition, the dielectric constant of the ceramics doping with Co was higher than that of the pure ...

2006-08-25

274

Effect of boron doping in the carbon support on platinum nanoparticles and carbon corrosion

The fundamental optical properties of dysprosium (Dy) doped strontium sulfide bulk samples for various dopant concentrations from 0.1 to 1.0 at.% were investigated by X-ray diffraction (XRD), electron paramagnetic resonance spectroscopy (EPR), room temperature photoluminescence (PL), photoluminescence excitation (PLE) and diffuse reflectance spectroscopy (DRS). Investigations by electron paramagnetic resonance yielded the state of Dy in the sample as Dy3+. An additional ESR line due to F+ center was observed. The PL emission spectrum consisted of several intense lines and a number of weaker ones which were identified as transitions between energy levels of Dy3+. The optimum doping concentration for maximum intensity was found to be 0.25 at.%. Blue shift of the absorption edge energy and red shift of the PLE spectrum were observed with increasing doping concentration. The former is due to Burstein-Moss (BM) effect and the ...

2010-08-13

275

Effect of Li-Al co-doping on the energy gaps of MgB2

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 between the Pt ...

2009-07-15

276

Boron transient enhanced diffusion in heavily phosphorus doped silicon

We studied the effects of co-doping with Li and Al on the energy gaps of MgB2 by performing point-contact Andreev-reflection spectroscopy (PCAR) in polycrystalline Mg1-x(Al?Li1-?)xB2 samples with x?0.4. Even though the lattice parameters and the critical temperature of the compound simply scale with the effective Al content ?x, irrespective of the Li concentration, the energy gaps do not. In particular, for a given effective Al content, the comparison with Mg1-y(Al)yB2 with y = ?x shows that the ? bandgap is practically the same while the ? bandgap is higher. A clear gap merging is observed in the most doped sample (x = 0.4) when Tc<20 K. The results are discussed within the two-band Eliashberg theory and compared to the outcomes of first-principles calculations of the effects of Li and Al co-doping on the electronic structure of magnesium diboride.

2009-02-01

277

Ultrashallow P{sup +}/N junction formation by plasma ion implantation

A study has been made of B transient enhanced diffusion (TED) in heavily P-doped Si using secondary ion mass spectroscopy (SIMS) and positron annihilation spectroscopy (PAS). The P-doped silicon was implanted with boron ions of 40 keV energy to a dose of 3 {times} 10{sup 14} cm{sup {minus}2}, and then annealed at temperatures ranging from 700--1,000 C in a N{sub 2} ambient for varying durations. As P doping concentration increased from 3 {times} 10{sup 19} to 1 {times} 10{sup 20} cm{sup {minus}3}, boron diffusivity and the immobile boron fraction decreased. The experimental results are inconsistent with the predictions of the Fermi-level model and suggest that the clustering between B atoms and Si interstitials should be invoked in order to explain the immobile portion of the B peak during TED.

1997-11-01

278

Ultrashallow P"+/N junction formation by plasma ion implantation

We investigated the electrical characteristics and the junction depth of ultra-shallow junctions formed by using the plasma-doping method. Compared with ultra-low energy boron-ion implantation at 500 eV, the junctions formed with the plasma-doping process exhibited shallow junction depths and low sheet resistances. The junction depths of the plasma-doped samples were 150 A and 330 A after annealing for 10 s at 900 .deg. C and 950 .deg. C, respectively. For the same junction depth, the sheet resistance of the B{sub 2}H{sub 6} plasma-doped sample was an order of magnitude less than that of the 500-eV B-ion implanted sample. Cross-sectional transmission electron microscopy and deep level transient spectroscopy showed that the defects formed by the B{sub 2}H{sub 6} plasma-doping process could be removed by annealing at 950 .deg. C for 10 s. The scaling of metal-oxide-semiconductor ...

2000-12-01

279

Real time neutron diffraction study on the reaction of AsF/sub 5/ with deuterated polyparaphenylene

We investigated the electrical characteristics and the junction depth of ultra-shallow junctions formed by using the plasma-doping method. Compared with ultra-low energy boron-ion implantation at 500 eV, the junctions formed with the plasma-doping process exhibited shallow junction depths and low sheet resistances. The junction depths of the plasma-doped samples were 150 A and 330 A after annealing for 10 s at 900 .deg. C and 950 .deg. C, respectively. For the same junction depth, the sheet resistance of the B_2H_6 plasma-doped sample was an order of magnitude less than that of the 500-eV B-ion implanted sample. Cross-sectional transmission electron microscopy and deep level transient spectroscopy showed that the defects formed by the B_2H_6 plasma-doping process could be removed by annealing at 950 .deg. C for 10 s. The scaling of metal-oxide-semiconductor field-effect-transistor ...

2000-12-01

280

Method of forming solar cells by grid contact isolation

The doping of deuterated polyparaphenylene (C/sub 6/D/sub 4/)sub(n) with AsF/sub 5/ has been investigated by real time neutron diffractometry at 100, 400 and 820 mbar AsF/sub 5/ pressure. The reaction appears to be diffusion controlled. Evidence for one doped phase with partial crystalline order was obtained. Structural considerations suggest two polymer chains plus one dopant ''string'' as the repetitive unit.

1982-07-01

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281

Luminescent lanthanide-ion doped nanoparticles as single-biomolecule labels and oxidant sensors

A solar cell structure is produced by a method comprising baking the solar cell, containing a gridded top layer of cuprous sulfide formed on a base of cadmium sulfide, for 20 minutes to 10 hours, to produce a copper doped cds electrically insulating region in the cadmium sulfide base near the interface of the cuprous sulfide and the cadmium sulfide; removing the cuprous sulfide, and the copper doped cds insulating region not covered by the grid, to provide a bare cadmium sulfide areas; and then forming a cuprous sulfide layer on the exposed areas not covered by the grid.

1982-03-16

282

Investigation of new materials for SOFC applications; Untersuchungen zum Einsatz neuer Werkstoffe fuer SOFC-Anwendungen

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.

2007-02-01

283

Helium atom doping of molybdenum and its influence on the radiation hardenings

Fuel cells based on solid oxides ('SOFC') are excellent alternative devices for power generation, when they are operated at high temperature, e.g. above 600 C. Having only fixed parts for the power generating part of the device is only one advantage of the fuel cell. Due to their unique design, these devices offer a maximum of efficiency for energy conversion compared to conventional power generating systems, which are mainly based on turbines. One aim of this thesis is the examination of alternative electrolyte and cathode materials for the SOFC applications at reduced temperatures, which means in the temperature range between 600 C and 750 C. For the first main task, several materials from the oxygen ion conducting electrolytes were selected. Different strontium and magnesium doped lanthanum gallate (LSGM) materials with additional transition metal doping were selected and prepared via two different preparation methods. The ...

2007-05-04

284

Fluorescence resonance energy transfer using lanthanide-ion doped oxide nanoparticles as donors

Experimental results on study of helium concentration influence on degree of molybdenum radiation hardening for various method of cyclotron doping differing in degree and damage character are presented. It is established that accumulation of helium atoms in molybdenum for simultaneous formation of radiation defects caused by low energetic primary-knocked atoms leads to higher degree of hardening than for high energetic ion irradiation. It is shown that with increase of helium atom concentration the degree of radiation hardening for the same level of damage increases. 4 refs.; 3 figs. (author).

1990-05-22

285

ESR study of X-ray irradiated rare earth (Ln) ion-doped glaserite and Ln ion-doped langbeinite

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.

2006-03-01

286

ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

X-ray irradiation-induced paramagnetic radicals in rare earth (Ln) ion-doped glaserite and Ln ion-doped langbeinite were studied by means of ESR technique, aiming at developing the highly sensitive sensor for an ESR dosimetry. The samples were prepared by two kinds of procedures as follows. In one process, the glaserite (K{sub 3}Na(SO{sub 4}){sub 2}) matrix or the langbeinite (K{sub 2}Mg{sub 2}(SO{sub 4}){sub 3}) matrix were synthesized by heating the mixture of K{sub 2}SO{sub 4} and Na{sub 2}SO{sub 4} or the mixture of K{sub 2}SO{sub 4} and MgSO{sub 4} at 1023 K for 1 hour in He flow. The matrices obtained were mixed well with a fixed amount of Ln{sub 2}(SO{sub 4}){sub 3} (Ln=La, Eu, Gd, Lu) powder and heated at 1023 K for 1 hour in He flow. In the other process, the homogeneous mixture of a fixed amount of K{sub 2}SO{sub 4}, Na{sub 2}SO{sub 4} and Ln{sub 2}(SO{sub 4}){sub 3} powders or a fixed amount of K{sub 2}SO{sub 4}, MgSO{sub 4} and ...

1992-06-01

287

Point-contact Andreev-reflection spectroscopy in MgB{sub 2}: The role of substitutions

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system. Taken as a whole, they confirm significant ...

2004-08-01

288

Nonaqueous synthesis of metal oxide nanoparticles: Short review and doped titanium dioxide as case study for the preparation of transition metal-doped oxide nanoparticles

We summarize the results of point-contact Andreev-reflection (PCAR) spectroscopy in MgB{sub 2} doped by chemical substitutions, either magnetic (Mn) or non-magnetic (Al,C), obtained by us and by other groups in the last four years. Despite the variety of samples used (crystals and polycrystals of various origin) and some minor differences in the experimental techniques, these measurements have directly provided a complete and consistent picture of the effects of chemical substitutions on the gaps of MgB{sub 2} shedding light on other relevant parameters (scattering rates, DOSs) affected by doping. In Al-doped crystals and polycrystals, the gap amplitudes {delta}{sub {sigma}} and {delta}{sub {pi}} - obtained through a two-band Blonder-Tinkham-Klapwijk (BTK) fit of the Andreev-reflection conductance curves - decrease on increasing the Al content x (i.e. on decreasing the critical temperature of the contacts T{sub c}{sup A}), ...

2007-06-01

289

Magnetic and transport properties of Ba_2Co_9O_1_4 and Ba_1_._9A_0_._1Co_9O_1_4 (A=La or Na)

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. Furthermore, obviously even the crystal structure can differ from the corresponding ...

2008-07-15

290

Electronic properties of doped CuPc layers

The valence and spin-state distributions of Co ions and the complex structure of antiferromagnetic Ba_2Co_9O_1_4 have led to the suggestion that doped Ba_2Co_9O_1_4 compounds may be good thermoelectric materials. We have checked this suggestion by measuring the magnetic properties as well as the transport properties of nominal Ba_1_._9A_0_._1Co_9O_1_4 (A=La or Na). We show that although all compounds are indicated to be single phase by powder X-ray diffraction analysis, they are all p-type polaronic conductors with low mobile-hole concentrations. Magnetic-susceptibility data of the parent and La-doped compounds give evidence of a second magnetic phase with ferromagnetic order setting in below 215 K; but this second phase is not seen in the Na-doped sample. We conclude that the structure is stabilized by oxidation and that cation exolution from the Ba_2Co_9O_1_4 structure creates cation vacancies that oxidize the high-spin ...

2010-11-01

291

Using fiber optic sensors to protect intake, outflow, and other environmentally exposed openings

Doping of molecular organic materials is important for the functionality of organic electronic devices as e.g solar cells. We investigated the doping behaviour of the acceptor molecules Cl{sub 2}-DCNQI and F{sub 16}CuPc incorporated into a CuPc matrix. In-situ XPS/UPS measurements were performed on coevaporated films. Doping by Cl{sub 2}-DCNQI was not successful. The molecule lost its chlorine atoms during thermal evaporation. For pristine F{sub 16}CuPc layers we observe a strong broadening of the photoemission features with increasing deposition rate indicating different domains probably of different molecular structure of differing electric interface potential. F{sub 16}CuPc incorporated into CuPc shows sharp photoemission features. With increasing F{sub 16}CuPc content Fermi level shifts are observed in both phases. In CuPc the maximum shift is about 0.45 eV towards the HOMO level indicating ...

2009-07-01

292

Thermal expansion model for multiphase electronic packaging materials

This paper reports on the protection of opening that are exposed to the environment in nuclear facilities which presents an almost overwhelming engineering challenge. Intakes and outflows must permit the passage of large volumes of air or water without impeding their flow, and they are often exposed to corrosive salt and chemicals. An intrusion detection sensor that is intended to protect these openings must be capable of operating reliably under environmentally harsh conditions, and at the same time either provide a physical delay barrier or attach to an existing barrier. A new fiber optic sensor technology has now been developed specifically for protecting environmentally exposed openings. This sensor uses a fiber optic cable embedded in a neoprene rubber frame which is reinforced with Kevlar threads or braided steel cable. The sensor is configured in a mesh pattern with openings sufficiently large to permit air or water to flow unimpeded, ...

1991-01-01

293

Studies on localization of calcitonin gene-related peptide (CGRP) in the thyroid-parathyroid complex.

Control of thermal expansion is often necessary in the design and selection of electronic packages. In some instances, it is desirable to have a coefficient of thermal expansion intermediate between values readily attainable with single or two phase materials. The addition of a third phase in the form of fillers, whiskers, or fibers can be used to attain intermediate expansions. To help design the thermal expansion of multiphase materials for specific applications, a closed form model has been developed that accurately predicts the effective elastic properties of isotropic filled materials and transversely isotropic lamina. Properties of filled matrix materials are used as inputs to the lamina model to obtain the composite elastic properties as a function of the volume fraction of each phase. Hybrid composites with two or more fiber types are easily handled with this model. This paper reports that results for glass, quartz, and Kevlar ...

294

Removal of SO sub x in flue gas by polyacrylonitrile based active carbon fiber (PAN-ACF). Polyacrylonitrile no kassei tanso sen prime ikei (PAN-ACF) no haien datsuryuno

Calcitonin gene-related peptide (CGRP) was localized by an immunocytochemical technique in the thyroid-parathyroid complexes of rat, guinea pig, rabbit, and in normal human thyroids and parathyroids. Human medullary carcinomas and parathyroid adenomas were also studied. In man and all animal species examined CGRP was present in the parafollicular cell, however, in guinea pigs only in small amounts. Except in rabbits, presence of CGRP was demonstrated in nerves of the thyroid and parathyroid capsule as well as in the nerve fibers of the capsular blood vessels. In the thyroid of guinea pigs CGRP was also noted in nerve fibers and in blood vessel walls between follicles. CGRP was also present in the parathyroid glands of rat and man, in nerve fibers localized between parathyroid cells. In rabbit the parafollicular cells between parathyroid cells also expressed CGRP immunoreactivity. No CGRP was noted in the parathyroids of the ...

1987-01-01

295

Measurement of the mean energy of the off-axis incident electron without the beam guide. Using a scintillating fiber beam-energy monitor for electron beam therapy

Flue gas desulfurizing capacities of active carbon fibers (ACF) made from polyacrylonitrile (PAN-ACF) were studied, the features were clarified and at the same time the factors governing the capacities were studied to get guides for better products. Desulfurization capacities of 17 kinds of ACFs were studied. Two kinds of PAN-ACF, FE-200 and FE-300, especially the latter exhibited the higher desulfurization capacity. The capacity of FE-300 was about 20 times higher than those of fibers other than PAN systems and about 4 times higher than that of active coke for desulfurization. From the influence of reacting conditions on the desulfurizating capacity and the desorption profiles of adsorbed SO {sub 2}, it was concluded that the capacity was determined by the effective adsorption capacity of ACF and SO {sub 2} was retained on ACF as sulfuric acid. It was suggested that main factors governing the adsorption capacity were the large surface area of ...

1991-04-10

296

Effect of ethnicity and treatments on in situ tensile response and morphological changes of human hair characterized by atomic force microscopy

In the case of total skin electron therapy without the beam guide, the electron beam is scattered just outside the gantry exit, dose uniformity in the field is broken, and dose is spread outside the light field. The aims of this study were to measure the mean energy of the off-axis incident electron beam without the beam guide and to establish a reference for the clinical situation. For the measurement, a 4 MeV electron beam was selected among several energies from the linear accelerator. A scintillating fiber beam energy monitor measured the mean energy of the incident electron beam. This energy monitor is a small, light-weight piece of equipment composed of a wedge absorber, scintillation fiber, and photodiode. We found the relationship between electron energy and the indicated value of the energy monitor by means of the estimation of correction factors for five different kinds of electron energy. The preferable linear correlation of 0.997 of ...

2002-06-01

297

Effect of Al and Be ions pre-implantation on formation and growth of helium bubbles in SiC/SiC composites

Human hair fibers experience tensile forces during grooming and styling processes. The tensile response of hair is hence of considerable interest to the cosmetics industry. In this study, in situ tensile characterization studies have been carried out in an atomic force microscope (AFM) on different hair under different conditions. A custom-built AFM sample stage allows hair fibers to be loaded in tension. A technique to locate and image the same control area at different strains has been developed to study the changes in morphology that occur with deformation. Virgin Caucasian, Asian and African hair were studied to understand the differences between different ethnic hair types. Also, the tensile response and morphological changes of virgin, chemically damaged and conditioner-treated Caucasian hair after soaking were compared against the corresponding dry tensile response. Finally, virgin, damaged and treated Caucasian hair ...

2008-08-01

298

Effect of Al and Be ions pre-implantation on formation and growth of helium bubbles in SiC/SiC composites

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si{sup 2+}, 1.0-MeV He{sup +} and 340-keV H{sup +}) at 1000 deg. C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. The size of He bubbles in the fiber was slightly increased by implanting Al or Be ions. ...

2007-03-15

299

Carbon-bonded carbon fiber insulation for radioisotope space power systems

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si"2"+, 1.0-MeV He"+ and 340-keV H"+) at 1000 deg. C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. The size of He bubbles in the fiber was slightly increased by implanting Al or Be ions. These results ...

2007-03-01

300

Carbon-bonded carbon fiber insulation for radioisotope space power systems

A carbon-bonded carbon fiber (CBCF) insulation developed for a radioisotope heat source is made from chopped rayon fiber about 10..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF is an excellent lightweight insulating material with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W/(m-K) in vacuum at 2000/sup 0/C. (Several attributes that make CBCF particularly suitable for the heat source application have been identified.) These include light weight, low thermal conductivity, chemical compatibility, and hightemperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the application. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to increase the fabrication rate by a factor of 10. The specific properties of the CBCF were ...

1985-05-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

301

Aluminum nitride precipitation and texture development in batch-annealed bake-hardening steel

A carbon-bonded carbon fiber (CBCF) insulation developed for a radioisotope heat source is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF is an excellent lightweight insulating material with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W/(m-K) in vacuum at 2000/sup 0/C. Several attributes that make CBCF particularly suitable for the heat source application have been identified. These include light weight, low thermal conductivity, chemical compatibility, and high-temperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the application. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to increase the fabrication rate by a factor of 10. The specific ...

1985-05-01

302

A new porous-layer activated-charcoal-coated fused silica fiber: application for determination of BTEX compounds in water samples using headspace solid-phase microextraction and capillary gas chromatography

A model is presented that describes the development of texture during the production process of bake-hardening steel recrystallized in a batch-annealing furnace. Proper conditions are analyzed to generate a pronounced {gamma}-fiber texture and a pancake microstructure that shows superior deep drawability. The {gamma}-fiber texture is assumed to be caused by the interaction between tertiary precipitating aluminum nitride particles and the recrystallization process during heating in the furnace. Deep drawability is presented in terms of the logarithmic {gamma}- and {alpha}-fiber X-ray intensity ratio. The computer simulation of the coupled aluminum nitride precipitation and recrystallization kinetics is based on an iterative procedure. A comparison between simulation results and available experimental data proves the ability of the model to predict the final deep drawability, taking into account the initial aluminum and ...

1999-06-01

303

Weather ability studies of phenolic resin coated woods and glass fiber reinforced laminates

Extra-fine powdered activated charcoal has been used as stationary phase (coating layer) in solid-phase microextraction (SPME). The efficiency and reliability of the prepared device have been investigated for the extraction of some volatile organic compounds such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) from the headspace of water samples. Monitoring of the extracted compounds and further quantitative analysis of the real samples have been performed by capillary GC-FID. Effects of several factors such as temperature, addition of salt, and stirring speed on extraction efficiency and exposure time have been studied. Under optimum conditions, extraction recoveries for these compounds from 50 mL water were >95%. The calibration graphs were linear in the range 5 to 10{sup 4} pg mL{sup -1} and the detection limit for each BTEX compound was 1.5-2 pg mL{sup -1}. The results obtained by use of this porous layer activated charcoal (PLAC)-coated fiber ...

1997-12-31

304

Wear resistant composite structure of vitreous carbon containing convoluted fibers

Phenolic resins have made a major breakthrough in the field of high technology in 80's. These are now active participants of "high tech' areas ranging from electronics, computers, communication, outer space, aerospace, advanced materials, bio materials and technology. A phenol - formaldehyde (1:1.5) resin having resin content of 70% synthesized in the laboratory has been applied for wood coating and reinforcing glass fiber. The weatherability and solvent resistance of these items have been studied and results discussed keeping in view the envisaged application for structural materials and chemical equipment. The toxic materials released during contact with solvents for chemical applications and during degradation general have been monitored. The results are discussed with reference to environmental pollution due to these resins and their composites under different conditions. (authors)

1997-09-01

305

The deformation texture in an AZ31B magnesium alloy

Very good friction and wear measurements are reported for MRCC (metal reinforced carbon composites), made from low-wear non-graphitic carbon matrix with metal-fiber reinforcement. Counterfaces include austenitic and martensitic stainless steels, Si nitride, and alumina. Effects of high load, high temperature, and gaseous environments are reported: removal of humidity, atm. oxygen have little effect on friction, wear for MRCC sliding against ceramic or stainless steel. Wear of Al oxide riders on MRCC is very low, not affected by contact load. 260 C temperatures do not degrade performance of 440-C riders on MRCC disks or raise friction. In small or large sizes, MRCC is made in a single-pass process for about the same volume cost as cast iron. It can survive heating in nitrogen above 1600 C without loss of integrity or major change of dimensions.

1995-02-01

306

The carbon fiber surface treatment and addition of PA6 on tensile properties of ABS composites

Extruded and hot-rolled 200 C {proportional_to} 500 C AZ31B plates were studied their texture using ODFs analysis. The as-extruded specimen has the strongest intensity of (0001)-ND fiber and 300 C and 400 C hot-rolled ones have the next, but the 200 C hot-rolled one has the lowest intensity. Compared with the corresponding tensile properties, this feature evidents that a pronounced (0001) basal texture will reduce ductility of AZ31B alloy. The ODFs results also indicate that (05 anti 52)- and (01 anti 10)-ND fibers are related to the ductility of AZ31B alloy. (orig.)

2003-07-01

307

British Library Electronic Table of Contents (United Kingdom)

In this study acrylonitrile-butadiene-styrene (ABS) terpolymer was reinforced with HNO3-treated short carbon fibers (HCFs). The effects of HCF concentration on the tensile properties of the composites were examined. Increasing the HCF concentration in the ABS matrix from 10 wt% to 30 wt% resulted in improved tensile strength and tensile modulus. To obtain a strong interaction at the interface, polyamide-6 (PA6) at varying concentrations was introduced into the ABS/10 wt% HCF composite. The incorporation and increasing amount of PA6 in the composites increased tensile properties of the ABS/PA6/HCF systems due to the improved adhesion at the interface, which was confirmed by the ratio of tensile strength as an adhesion parameter. These results were also supported by scanning electron microgr...

2011-01-01

308

Surface characteristics and overlaying properties of flat-pressed wood plastic composites

British Library Electronic Table of Contents (United Kingdom)

This study evaluated surface characteristics and overlaying properties of wood plastic composite (WPC) panels made from dry-blended rubber wood fiber-polypropylene (PP) powder formulations using a conventional flat-press process under laboratory conditions. Three levels of rubberwood fibers (Hevea brasiliensis), 40%, 50%, and 60%, based on the composition by weight, were mixed with the PP powder without and with 3% (based on weight) maleic anhydride grafted PP (MAPP) as a coupling agent. Contact angle measurements on the WPC samples were performed using a goniometer connected with a digital camera which collected one image per second. Roughness measurements, average roughness (R a), mean peak-to-valley height (R z), and maximum roughness (R y), were taken from the sanded samples along and ...

2011-01-01

309

Reinforced concrete beam-column joint strengthened with carbon fiber reinforced polymer

British Library Electronic Table of Contents (United Kingdom)

An effective rehabilitation strategy is proposed to enhance the strength and stiffness of the beam-column joint in this study. An analytical model is proposed to predict the column shear of the joints strengthened with carbon fiber reinforced polymer (CFRP). Three full scale interior beam-column joints, including two specimens strengthened with CFRP and one prototype specimen, are tested in this study. The specimens are designed to represent the pre-seismic code design construction in which there is no transverse reinforcement. A new optical non-contact technique, digital image correlation (DIC), which can measure the full strain field of specimen, is used to measure and observe the full strain field of the joint. The experimental results show that the beam-column joints strengthened with ...

2010-01-01

310

Modeling of ablation by photospallation using the computer program PUFF/DFRACT

High channel density wavelength division multiplexer with defined diffracting means positioning

In general, macroscopic material failure is a manifestation of irreversible changes at the microscopic level. Many tissues, which may appear to be macroscopically homogeneous, are, at a fundamental microscopic level, a composite material. For example, cornea is composed of a hyaluronic acid matrix in which layers of collagen fibers are overlaid in a crossing pattern. The points where the collagen fibers intersect are potential nucleation sites for microscopic defects, which under the action of tensile stress, nucleate, grow and coalesce to form macroscopic failure planes, or spall planes. Using a model based on microstructural evolution, this paper examines the failure process during photoablation. Specifically, the paper describes a physically motivated, micromechanical model based on the nucleation and growth of spherical voids. This model is then used to simulate photoablation of cornea. Potential for using this model to predict the stress ...

1995-03-01

311

Flood scour monitoring system using fiber Bragg grating sensors

A wavelength division multiplexer/demultiplexer having optical path lengths between a fiber array and a Fourier transform lens, and between a dispersion grating and the lens equal to the focal length of the lens. The optical path lengths reduce losses due to angular acceptance mismatch in the multiplexer. Close orientation of the fiber array about the optical axis and the use of a holographic dispersion grating reduces other losses in the system. Multi-exposure holographic dispersion gratings enable the multiplexer/demultiplexer for extremely broad-band simultaneous transmission and reflection operation. Individual Bragg plane sets recorded in the grating are dedicated to and operate efficiently on discrete wavelength ranges.

1990-01-01

312

Enhanced catalytic activity of Fe bimetallic modified PAN fiber complexes prepared with different assisted metal ions for degradation of organic dye

The exposure and subsequent undermining of pier/abutment foundations through the scouring action of a flood can result in the structural failure of a bridge. Bridge scour is one of the leading causes of bridge failure. Bridges subject to periods of flood/high flow require monitoring during those times in order to protect the traveling public. In this study, an innovative scour monitoring system using button-like fiber Bragg grating (FBG) sensors was developed and applied successfully in the field during the Aere typhoon period in 2004. The in situ FBG scour monitoring system has been demonstrated to be robust and reliable for real-time scour-depth measurements, and to be valid for indicating depositional depth at the Dadu Bridge. The field results show that this system can function well and survive a typhoon flood.

2006-12-01

313

British Library Electronic Table of Contents (United Kingdom)

Two transition metal ions (Cu^2^+ and Co^2^+) and two rare earth metal ions (Ce^3^+ and La^3^+) were used as the assisted metal ions, respectively to prepare the transition metal and rare metal assisted Fe bimetallic amidoximated polyacrylonitrile (AO-PAN) fiber complexes. And their coordination configuration and visible light adsorption properties were examined by coordination number determination and UV-vis-DRS. Then the catalytic performance of these complexes was evaluated as the heterogeneous Fenton catalysts in Rhodamine B degradation by changing the nature and dosage of the assisted ions added. The results indicated that the incorporation of the assisted metal ions led to Fe bimetallic AO-PAN complexes with the more unsaturated configurations than Fe monometallic AO-PAN complex due ...

2011-01-01

314

Electrospinning of poly(vinyl pyrrolidone)-iodine complex and poly(ethylene oxide)/poly(vinyl pyrrolidone)-iodine complex - a prospective route to antimicrobial wound dressing materials

British Library Electronic Table of Contents (United Kingdom)

New nanofibers containing poly(vinyl pyrrolidone)-iodine complex (PVP-iodine) were obtained by electrospinning in order to prepare materials suitable for wound dressings. Different approaches were used: a one-step method based on electrospinning of PVP-iodine or poly(ethylene oxide)/PVP-iodine solutions and a three-step method based on electrospinning of PVP or poly(ethylene oxide)/PVP mixed solutions followed by photo-mediated crosslinking of the obtained nanofibers and subsequent complexation with iodine. The average diameters of the fibers were in the range 150-470nm depending on the composition and on the applied field strength (AFS) and increased with increasing the amount of PEO in the spinning solutions. Higher AFS resulted in greater fiber diameter and in size distribution broadeni...

2007-01-01

315

Chromatographic evaluation of microbial activity in biological activated carbon bed; Kuromatoho ni yoru seibutsu kasseitanso ni okeru biseibutsu kassei no hyoka

Charging a Battery-Powered Device with a Fiber-Optically Connected Photonic Power System for Achieving High-Voltage Isolation

The moment analysis of pulse responses was applied to a biological activated carbon (BAC) bed to evaluate the microbial activity. Glucose and activated carbon fiber (ACF) were employed in experiments as a model tracer and an activated carbon respectively. No significant difference in biodegradation rates of glucose by microorganisms attached on different solid supports such as activated carbon inactivated carbon and glass fibers was observed. However, higher microbial activity was obtained from microorganisms supported on the ACF in terms of the apparent degradation of total organic including metabolic byproducts by microorganisms, since part of the metabolic byproducts was irreversibly deposited onto the ACF. 11 refs., 6 figs.

1996-07-10

316

White luminescence of Tm-Dy ions co-doped aluminoborosilicate glasses under UV light excitation

This paper describes the development and testing of a system to provide isolated power to the cathode-subsystem electronics of an x-ray tube. These components are located at the cathode potential of several hundred kilovolts, requiring a supply of power isolated from this high voltage. In this design a fiber-optically connected photonic power system (PPS) is used to recharge a lithium-ion battery pack, which will subsequently supply power to the cathode-subsystem electronics. The suitability of the commercially available JDSU PPS for this application is evaluated. The output of the ppe converter is characterized. The technical aspects of its use for charging a variety of Li-Ion batteries are discussed. Battery charge protection requirements and safety concerns are also addressed.

2008-01-01

317

Transient enhanced diffusion of boron in silicon: The interstitial flux

Tm3+ and Dy3+ ions co-doped aluminoborosilicate glasses were prepared in this study. The luminescence properties of the glasses were analyzed. A combination of blue, green, yellow, and red emission bands was shown for these glasses, and white light emission could be observed under UV light excitation. White light luminescence color could be changed by varying the excitation wavelength. Concentration quenching effect was investigated in this paper. Furthermore, the dependence of luminescence properties on glass compositions was studied. Results showed that the luminescence intensity changed with different network modifier oxides, while the white color luminescence was not affected significantly. - Graphical abstract: Tm3+ and Dy3+ ions co-doped aluminoborosilicate glasses, which emit white light under UV light excitation, were prepared. The dependence of luminescence properties on glass compositions was studied, and results showed that the white ...

2008-10-01

318

Transient enhanced diffusion of boron in silicon: The interstitial flux

Delta-doped boron marker layers in silicon have been used to test further the relationship between B transient enhanced diffusion (TED) and the flux of silicon interstitials released during the annealing stage following self implantation. The authors present new data which address a number of questions raised by the present models. They show that in the experiments bulk trapping of interstitials is significant only for low implant fluences ({approximately}10{sup 12} cm{sup {minus}2}). The origin of the observed diffusion-like profiles for the interstitial flux is instead found to lie in local trapping within the {delta}-doped layers themselves. Boron trapped in immobile clusters may be associated with Si interstitials in approximately a 1:1 ratio; nevertheless this trapping contribution alone may not entirely account for the observed gradient. They suggest that some part of the observed TED response with depth is attributable to local trapping ...

1997-11-01

319

Synthesis and photoluminescence properties of Sm3+-doped LaMgB5O10 and GdMgB5O10

Delta-doped boron marker layers in silicon have been used to test further the relationship between B transient enhanced diffusion (TED) and the flux of silicon interstitials released during the annealing stage following self implantation. The authors present new data which address a number of questions raised by the present models. They show that in the experiments bulk trapping of interstitials is significant only for low implant fluences (#approx#10"1"2 cm"-"2). The origin of the observed diffusion-like profiles for the interstitial flux is instead found to lie in local trapping within the #delta#-doped layers themselves. Boron trapped in immobile clusters may be associated with Si interstitials in approximately a 1:1 ratio; nevertheless this trapping contribution alone may not entirely account for the observed gradient. They suggest that some part of the observed TED response with depth is attributable to local trapping of silicon ...

1996-12-02

320

Surface Fermi level engineering: Or there's more to Schottky barriers than just making diodes and field effect transistor gates

Luminescence and reflection spectra as well as luminescence kinetics of the 1 mol% Sm3+-doped crystalline lanthanum magnesium meta borate (LaMgB5O10) and gadolinium magnesium meta borate (GdMgB5O10) were analyzed. Materials were synthesized by conventional solid state route and showed bright orange-red emission under UV excitation. Emission spectra contain sharp and well resolved Sm3+4G5/2#->#6HJ transitions indicating a strong crystal-field effect. In case of gadolinium compound energy transfer between Gd3+ and Sm3+ was detected. The luminescent kinetics of the Sm3+ in analyzed powders is characterized by single exponential decay and experimental values vary in the range 2.2-2.4 ms. - Research highlights: ? Phosphorescence of samarium-doped lanthanide magnesium meta borates. ? Bright and well resolved orange-red emission of Sm3+ under UV excitation. ? Energy transfer from Gd3+ to Sm3+ in gadolinium magnesium meta borate is observed. ? The ...

2011-07-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

321

Structural and morphology studies of praseodymium-doped bismuth titanate prepared using a wet chemical route

Surface scientists argue about the fundamental nature of Schottky barriers, or more precisely what determines the location of the Fermi level at semiconductor surfaces and interfaces. Electrical and materials engineers worry about how to make Schottky barrier diodes and gates to field effect transistors and the control of barrier heights. There is some interesting middle ground in which the location of the surface and interface Fermi level can, for example, determine semiconductor doping characteristics during crystal growth. The authors will discuss several interesting and well known examples of doping characteristics which are still somewhat mysterious. Specifically, they address the following question: (1) why is Ge doped GaAs p type when grown from Ga melts but n type when grown from Au melts (2) why is low resistivity p type ZnSe, AlAs, and AlGaInP hard to make, and more importantly, how can the problem be fixed. In ...

322

Structural and morphology studies of praseodymium-doped bismuth titanate prepared using a wet chemical route

Praseodymium-doped Bi{sub 4}Ti{sub 3}O{sub 12} (BIT) with various compositions of dopant, Pr (x = 0.5, 0.6, 0.7, 0.8) in Bi{sub 4-x}Pr{sub x}Ti{sub 3}O{sub 12} (BPT) were synthesized using a low temperature wet chemical technique. Powders calcined at 800 deg. C exhibit a single phase polycrystalline perovskite bismuth-layered structure. Randomly oriented plate-like structures were observed under Scanning Electron Microscope (SEM). A small amount of Pr doping (x = 0.5) resulted in dramatically reduced of grain size from 2 {mu}m to less than 50 nm in which Pr plays the role as a grain growth inhibitor. However, by increasing the composition of Pr, bigger grain size of up to 1 {mu}m was observed for x = 0.8 that was caused by diffusion of Pr in the perovskite structure. Dielectric properties showed that dielectric permittivity decreased with the addition of x = 0.50, and increasing with further addition of Pr. Dissipation factor (tan {delta}) ...

2009-05-05

323

Structural and morphology studies of praseodymium-doped bismuth titanate prepared using a wet chemical route

Praseodymium-doped Bi_4Ti_3O_1_2 (BIT) with various compositions of dopant, Pr (x = 0.5, 0.6, 0.7, 0.8) in Bi_4_-_xPr_xTi_3O_1_2 (BPT) were synthesized using a low temperature wet chemical technique. Powders calcined at 800 deg. C exhibit a single phase polycrystalline perovskite bismuth-layered structure. Randomly oriented plate-like structures were observed under Scanning Electron Microscope (SEM). A small amount of Pr doping (x = 0.5) resulted in dramatically reduced of grain size from 2 #mu#m to less than 50 nm in which Pr plays the role as a grain growth inhibitor. However, by increasing the composition of Pr, bigger grain size of up to 1 #mu#m was observed for x = 0.8 that was caused by diffusion of Pr in the perovskite structure. Dielectric properties showed that dielectric permittivity decreased with the addition of x = 0.50, and increasing with further addition of Pr. Dissipation factor (tan #delta#) followed the same trend as ...

2009-05-05

324

British Library Electronic Table of Contents (United Kingdom)

Praseodymium-doped Bi4Ti3O12 (BIT) with various compositions of dopant, Pr (x=0.5, 0.6, 0.7, 0.8) in Bi4-xPrxTi3O12 (BPT) were synthesized using a low temperature wet chemical technique. Powders calcined at 800degreeC exhibit a single phase polycrystalline perovskite bismuth-layered structure. Randomly oriented plate-like structures were observed under Scanning Electron Microscope (SEM). A small amount of Pr doping (x=0.5) resulted in dramatically reduced of grain size from 2mm to less than 50nm in which Pr plays the role as a grain growth inhibitor. However, by increasing the composition of Pr, bigger grain size of up to 1mm was observed for x=0.8 that was caused by diffusion of Pr in the perovskite structure. Dielectric properties showed that dielectric permittivity decreased with the ad...

2009-01-01

325

Single-crystal microwires based on doped Bi for anisotropic thermoelectric devices

Quality Management for Neutron Transmutation Doping of Silicon Ingot in HANARO

We have investigated the possibility to use a microwire of BiSn to design an anisotropic thermoelectric generator. The glass-coated microwire of pure and Sn-doped bismuth was obtained by the Ulitovsky method; it was a cylindrical single-crystal with orientation (1011) along the wire axis; the C3 axis was inclined at an angle of 70 degrees to the microwire axis. It is found that doping of bismuth wires with tin increases the thermopower anisotropy in comparison with Bi by a factor of 2 - 3 in the temperature range of 200-300 K. For a Bi microwire with a core diameter of 10 ?m with a glass coating with outer diameter of 35 ?m, the transverse thermopower is ? 150 ?V/(K*cm); for BiSn, 300 ?V/(K*cm). The design of an anisotropic thermogenerator based on BiSn microwire is proposed. The miniature thermogenerator will be efficient for power supply of devices with low useful current. In addition to the considerable thermopower anisotropy of BiSn wires ...

2011-07-07

326

Preparation of Eu-doped #beta#- and 15R-SiAlONs by ammonia nitridation of the precursor obtained using aluminum glycine gel

By using this doping method, silicon semiconductors with extremely uniform dopant distributions can be produced, and this is the dominant advantage of NTD compared with a conventional chemical doping. Good uniformity of a dopant concentration is usually required for high power applications such as thyristor (SCR), IGBT, IGCT and GTO and for special sensors. Achieving an accurate neutron fluence corresponding to a target resistivity as well as a uniform irradiation is the prime target of a neutron irradiation for NTD. Generally, in order to reach an accurate neutron fluence, a real time neutron flux is monitored by a neutron detector such as a Self-powered Neutron Detector(SPND). And, after an irradiation, the total irradiation fluence is confirmed by measuring the absolute activity of a neutron activation sample that has been irradiated with a silicon ingot, and thus the SPND can be properly calibrated. Excellent irradiation uniformity and a ...

2007-10-15

327

Lithium intercalation in porous carbon electrodes

Synthesis of Eu-doped #beta#- and 15R-SiAlONs was studied by the ammonia nitridation of precursors derived from an #alpha#-Si_3N_4 fine powder dispersed in aluminum glycine gel with various Si/Al ratio and post-annealing in a nitrogen pressure furnace. The largest amount of #beta#-SiAlON was observed in the product at 1750 deg. C for Si/Al = 1/1 with small amounts of both #alpha#- and 15R-SiAlON impurities. The product showed two emissions at around 420 nm and 560 nm. The emission intensities decreased with increasing amount of #beta#-SiAlON. The former and latter emissions were assigned to Eu"2"+ in the 15R- and #alpha#-SiAlONs impurities. A mixture of Eu-doped 15R-SiAlON with #alpha#-Al_2O_3 impurity was obtained for Si/Al = 1/6, using AlN together with Al(NO_3)_3.9H_2O in a 2/1 atomic ratio as the aluminum source. It showed a bluish-white emission at 450 nm under 254 nm radiation.

2009-11-13

328

Carbon nanotube coating silicon doped with Cr as a high capacity anode

Carbons derived from the phase separation of polyacrylonitrile/solvent mixtures were investigated as lithium intercalation anodes for rechargeable lithium-ion batteries. The carbon electrodes have a bulk density of 0.35-0.5 g/cm{sup 3}, relatively low surface areas (< 10 m{sup 2}/g), and micron-size cells. Pyrolysis temperature influences the reversible lithium intercalation and the irreversible capacity (associated with the formation of the passivating layer). Carbon electrodes pyrolyzed at 600{degrees}C have first-cycle capacity as high as 550 mAh/g as well as large irreversible capacity, 440 mAh/g. Electrodes prepared at 1050{degrees}C have reversible capacities around 270 mAh/g with relatively lower capacity losses (120 mAh/g). Doping the organic precursors with phosphoric acid, prior to pyrolysis at 1050{degrees}C, leads to carbon electrodes with reversible capacities as high as 450 mAh/g. The capacity of doped carbon increased with ...

1995-04-01

329

Al[sub 0. 3]Ga[sub 0. 7]As/GaAs heterojunction tunnel diode for tandem solar cell applications

Effects of dopant and coating carbon nanotube on anodic performance of Si were studied for metallic anode Li ion rechargeable battery with large capacity. Although the large Li intercalation capacity higher than 1500mAhg{sup -1} is exhibited on pure Si, it decreased drastically with increasing cycle number. Increasing the electrical conductivity by doping Cr or B is effective for increasing the initial capacity and the cycle stability of Si for Li intercalation. Coating semiconductive Si with the carbon nanotube by decomposition of hydrocarbon is effective for increasing the cycle stability, though the initial Li intercalation capacity slightly decreased. Conducting binder is also important for increasing the cycle stability and it was found that Li intercalation capacity higher than 1500mAhg{sup -1} can be sustained by using poly vinyliden fruolide. Consequently, reversible Li intercalation capacity of 1500mAhg{sup -1} was successfully sustained after 10th cycles ...

2005-08-26

330

VC- and Cr{sub 3}C{sub 2}-doped WC-NbC-Co hardmetals

A p[sup +]-Al[sub 0.3]Ga[sub 0.7]As/n[sup +]-GaAs heterojunction tunnel diode was fabricated using Atomic Layer Epitaxy (ALE) growth technique. Background carbon doping of [similar to]10[sup 20] cm[sup [minus]3] was achieved in the p-side of the diode by optimizing growth conditions such as V/III ratio, exposure times to reactant gases, and growth temperature. In the n-side of the diode GaAs was doped with silane and doping concentrations as high as 7[times]10[sup 18] cm[sup [minus]3] were also achieved. The dopants are chosen to satisfy the high levels and low diffusion requirements. The diode can be used to interconnect the high and low band-gap cells in the AlGaAs/GaAs cascade solar cell structure. The reactor used in this investigation is a commercial MOCVD system which has been specially modified for dual operation of ALE and MOCVD growth modes.

1994-06-30

331

Up-conversion luminescence saturation under pulsed excitation of erbium-doped, SiO_2-TiO_2 sol-gel powders

This study compares the microstructure and mechanical properties of plain and 0.9 or 3.6 wt% VC- or Cr{sub 3}C{sub 2}-doped WC-12 wt% Co hardmetals with 40 wt% NbC, prepared by pulsed electric current sintering (PECS) in the solid state for 4 min at 1240 deg. C and conventional pressureless liquid phase sintering (CS) for 1 h at 1420 deg. C. The addition of VC or Cr{sub 3}C{sub 2} was found to inhibit grain growth of the residual WC grains, whereas the size of the solid solution (Nb,W,V/Cr)C grains was hardly influenced. The type of grain growth inhibitor and densification temperature however, strongly influenced the composition of the NbC solid solution formed, which was thermodynamically and experimentally assessed.

2008-09-22

332

Towards atomic scale engineering of rare-earth-doped SiAlON ceramics through aberration-corrected scanning transmission electron microscopy

The intensity of erbium up-conversion luminescence could be limited by a saturation effect due to increased pump power. We studied the luminescence saturation of the 550 nm emission on erbium-doped, SiO_2-TiO_2 sol-gel powders under pulsed excitation at 979 and 1532 nm. From the latter, the up-converted luminescence intensity decreased with increasing excitation power, whereas no saturation was observed at 979 nm excitation. We proposed that the saturation effect is determined by the pump power, the erbium content and the lifetime of the corresponding first excited states at different pumping schemes.

2010-12-01

333

British Library Electronic Table of Contents (United Kingdom)

Direct visualization of rare earths in @a- and @b-SiAlON unit-cells is performed through Z-contrast imaging technique in an aberration-corrected scanning transmission electron microscope. The preferential occupation of Yb and Ce atoms in different interstitial locations of @b-SiAlON lattice is demonstrated, yielding higher solubility for Yb than Ce. The triangular-like host sites in @a-SiAlON unit cell accommodate more Ce atoms than hexagonal sites in @b-SiAlON. We think that our results will be applicable as guidelines for many kinds of rare-earth-doped materials.

2011-01-01

334

Thermoluminescence of irradiated RbCl and RbCl:Sn crystals

Thermo-transferred thermoluminescence (TTTl) in potassium-yttrium double fluoride doped with terbium

The thermoluminescence (TL) and emission of coloured RbCl and RbCl:Sn crystals are studied in the temperature range 300 to 560 K. The glow peaks responsible for F centres and tin centres in different valence states are identified using optical bleaching studies. The glow peaks are analysed using total curve fitting method and the kinetic parameters are determined. In moderately #gamma#-irradiated tin-doped RbCl crystals, the TL emission bands observed at 4.0, 3.6, and 2.2 eV are attributed to Sn"0, Sn"+, and Sn"- centers, respectively. A comprehensive energy level diagram depicting the various TL processes in these undoped and tin-doped RbCl crystals is proposed. (author).

335

The influence of Cl[sub 2] on Si[sub 1-x]Ge[sub x] selective epitaxial growth and B-doping properties by UHV-CVD

This paper presents results of studying the thermo-transferred thermoluminescence (TTTl) phenomenon in potassium-yttrium double fluoride doped with terbium (K_2YF_5_:Tb) at different impurity concentrations (0.8%, 0.95% and 0.99%). Previously to study the TTTl phenomenon, structural characterization and chemical composition of the materials were determined. The structural studies were conducted using a scanning electron microscope; meanwhile, chemical composition was analyzed using energy dispersive X-ray spectroscopy. Thermoluminescence kinetics was studied irradiating the samples with "1"3"7Cs gamma rays as well as with "9"0Sr/"9"0Y beta rays, analyzing the glow curves by the deconvolution method for obtaining the kinetic parameters. (Author)

2011-02-01

336

The Effect of Contacts on the Counting Characteristics of Heavily Doped Normal-Type Cadmium-Telluride

We report the influence of a small quantity of Cl[sub 2], which enhanced the selectivity of silicon-selective epitaxial growth (Si-SEG) in UHV-CVD using Si[sub 2]H[sub 6], on both the epitaxial growth rate and the B-doping properties for each Si and Si[sub 1-x]Ge[sub x] film. The small quantity of Cl[sub 2] inhibited the Si, Ge and B incorporation, while the selectivity was enhanced. However, it was found, in the case of Si[sub 1-x]Ge[sub x]-SEG using Cl[sub 2], that the reduction ratio of both the growth rate and the B incorporation were smaller than those of Si-SEG with the selectivity still more enhanced. (orig.)

1993-02-01

337

Superconductivity in cage doped fullerenes. Final report

Cadmium telluride single crystals were grown heavily doped with chloride by the THM method. The resulting crystals were n-type with free carrier concentrations of the order of 10('12)/cm at room temperature. Hall effect studies revealed room temperature mobilities between 30 and 350 cm('2)/v-sec and resistivites between 2 x 10('3) and 10('4) ohm-cm. Studies were made of the gamma and alpha counting characteristics of these crystals with metal, metal-semiconductor, and metal-insulator electrodes. It was found that the MIS and MSS structures resulted in significant improvement over the MS structures in counting, signal-to-noise and energy resolution.

1985-01-01

338

Study of point defect detectors in Si

Motivated by the discovery of superconductivity in alkali and alkaline earth fullerides, this program was undertaken both to understand the nature of and expand the range of materials demonstrating superconductivity. The first approach involved attempts to modify the fullerene cage by incorporating heteroatoms in the structure and the preparation and photophysical properties of nitrogen and sulfur doped fullerenes were studied in detail. The second approach involved examining the stoichiometry and effect of preparative conditions on the behavior of alkali, alkaline earth, lanthanide and mixed ion fullerides. In particular, the authors have elaborated on a technique for making such salts using liquid ammonia or aliphatic amines as solvents. Thirdly, modeling studies were undertaken to predict the properties of heterohedral fullerines and metal - C60 complexes, and theoretical guidelines were developed for understanding the reactivity of the fullerene cage to common ...

1996-08-26

339

Study of phase composition and mechanical properties of Al-Mg alloys doped with Ce and Y after various conditions of heat treatment

The importance of point defects in semiconductor and function materials has been studied in detail, but effective means for detecting point defects has not been available for a long time. The end of range defects in Si, produced by 140 keV Ge"+ implantation, were investigated as detectors for measuring the interstitial concentration created by 42 keV B"+ implantation. The concentration of interstitial resulting from the B"+ implantation and the behavior of the interstitial flux under different annealing condition were given. The enhanced diffusion in the boron doped EPI marker, resulting from mobile non-equilibrium interstitials was demonstrated to be transient. Interstitial fluxes arising from processing can be detected by transient enhanced diffusion (TED) of doped marker layers as well

1999-05-01

340

Spectroscopy of gadolinium gallium garnet crystals doped with Y b3+ revisited

By means of the light microscopy and by the measurement of the mechanical properties one investigated into the phase composition and the properties of Al-Mg-Ce and Al-Mg-Y system alloys. One plotted the isothermal cross sections of the mentioned systems under 430 and 275 deg C temperatures at up to 16% magnesium concentration and up to 0.7% yttrium concentration. One determined the yield limit and strength, the relative elongation of Al-Mg base hardened and deformed alloys containing 7.0-9.9% Mg and Ce, Y, Mn, Zr dopes upon ageing under 175, 200, 250 and 300 deg C temperatures within the ageing time ensuring the hardening maximum effect

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

341

Spectroscopic properties of Pr"3"+ doped LaWO_4Cl and La_3WO_6Cl_3

The optical spectroscopy measurements of gadolinium gallium garnet (GGG) crystals doped with Yb show evidence of the presence of non-equivalent optical centers with very similar radiative decay rates. The energy level schemes of those centers have been determined on the basis of optical absorption, luminescence and Raman experiments. Crystal field fitting resulted in two sets of slightly different crystal field parameters for two non-equivalent Yb centers. Both sets of parameters describe perfectly the experimentally detected Y b3+ energy levels. Correlation between systematic trends in the experimental energy level schemes and crystal field parameters is discussed.

2010-06-30

342

Spectroscopic properties of Pr sup 3+ doped LaWO sub 4 Cl and La sub 3 WO sub 6 Cl sub 3

The spectroscopic properties of Pr"3"+ doping two lanthanum chlorotungstate hosts: the orthorhombic LaWO4Cl (1-1) and the hexagonal La3WO4Cl6 (3-1), as well as those of PrWO4Cl and Pr3wO613 have been investigated. The simulations of the energy level schemes are carried out within the crystal field theory frame. Each simulation involves 7 free ion parameters and 14 non-zero crystal field parameters (cfps), corresponding to the C_s point symmetry of the site occupied by the rare earth, in both structures.

1992-01-01

343

SI/SIGE NANOWIRE ARRAYS FOR THERMOELECTRICITY

The spectroscopic properties of Pr{sup 3+} doping two lanthanum chlorotungstate hosts: the orthorhombic LaWO4Cl (1-1) and the hexagonal La3WO4Cl6 (3-1), as well as those of PrWO4Cl and Pr3wO613 have been investigated. The simulations of the energy level schemes are carried out within the crystal field theory frame. Each simulation involves 7 free ion parameters and 14 non-zero crystal field parameters (cfps), corresponding to the C{sub s} point symmetry of the site occupied by the rare earth, in both structures.

1992-01-01

344

Environmental Research Database

ObjectivesFor thermoelectricity both low thermal conductivity and high electrical conductivity are required. High electrical conductivity should be established via a high carriers concentration and a high mobility.~%~The aim of this feasibility study is to investigate a method of modulation doping of Si nanowires in order to generate high carrier concentrations without the need for impurity doping, thus retaining high mobilities.~%~~%~The objectives are (in chronological order):~%~- reduction of the wire [continued...]DescriptionIn recent years, the increasing dependence of society on fossil fuels for socio-economical development has become a cause of great concern. The possibility of a reduced availability of fossil fuels, and the effect of these fuels on climate change, have encouraged research into alternative energy sources. Many of these alternatives are old ideas, implemented using modern techniques. This proposal plans ...

2008-01-30

345

Radiation tolerant GaAs MESFET with a highly-doped thin active layer grown by OMVPE

Properties of transition metal-doped zinc chalcogenide crystals for tunable IR laser radiation

A new structure of GaAs MESFET with high radiation tolerance is proposed. Changes in electrical parameters of a GaAs MESFET as a function of total #gamma#-ray dose have been found to be caused mainly by a decrease in the effective carrier concentration in an active layer. The authors have designed a new structure from a simulation based on an empirical relationship between the changes of the effective carrier concentration and the total #gamma#-ray dose. It has been successfully demonstrated by utilizing a highly-doped thin active layer (4 x 10"1"8 cm"-"3, 100 Angstrom) grown by OMVPE. This MESFET can withstand a dose ten times higher [1 x 10"9 rads(GaAs)] than a conventional one can.

1990-07-16

346

Progress on polarized target materials with pure carbon background

The spectroscopic properties of Cr{sup 2+}, Co{sup 2+}, and Ni{sup 2+}-doped single crystals of ZnS, ZnSe, and ZnTe have been investigated to understand their potential application as mid-IR tunable solid-state laser media. The spectroscopy indicated divalent Cr was the most favorable candidate for efficient room temperature lasing, and accordingly, a laser-pumped laser demonstration of Cr:ZnS and Cr:ZnSe has been performed. The lasers` output were peaked at {approximately} 2.35 {mu}m and the highest measured slope efficiencies were {approximately} 20% in both cases.

1995-03-17

347

Progress on polarized target materials with pure carbon background

A previous note reviewed methods for the paramagnetic doping of materials for spin-polarized solid targets and some of the history of attempts to apply those methods to hydrocarbons. Since the earlier work on hydrocarbons had yielded, at best, rather mediocre results, that note also speculated on some ways to extend and, possibly, to improve upon the earlier work. The sharpest focus was on the light (number of carbons less than six) alkanes, since these are the hydrocarbons that have the highest hydrogen contents ([approx gt] 17wt %) and therefore require the least degree of polarization to be interesting. This present note summarizes the subsequent work done, to date, exploring some of the issues related to the chemical doping method. The main areas of progress have been in the literature search, experimental results on glass formation by alkanes, and a polarizing test of a prototype'' hydrocarbon.

1993-03-24

348

Progress on polarized target materials with pure carbon background

A previous note reviewed methods for the paramagnetic doping of materials for spin-polarized solid targets and some of the history of attempts to apply those methods to hydrocarbons. Since the earlier work on hydrocarbons had yielded, at best, rather mediocre results, that note also speculated on some ways to extend and, possibly, to improve upon the earlier work. The sharpest focus was on the light (number of carbons less than six) alkanes, since these are the hydrocarbons that have the highest hydrogen contents ([approx gt] 17wt %) and therefore require the least degree of polarization to be interesting. This present note summarizes the subsequent work done, to date, exploring some of the issues related to the chemical doping method. The main areas of progress have been in the literature search, experimental results on glass formation by alkanes, and a polarizing test of a prototype'' hydrocarbon.

1993-03-24

349

Preparation and photocatalytic property of pyrochlore Bi2Ti2O7 and (Bi, La) 2Ti2O7 films

A previous note reviewed methods for the paramagnetic doping of materials for spin-polarized solid targets and some of the history of attempts to apply those methods to hydrocarbons. Since the earlier work on hydrocarbons had yielded, at best, rather mediocre results, that note also speculated on some ways to extend and, possibly, to improve upon the earlier work. The sharpest focus was on the light (number of carbons less than six) alkanes, since these are the hydrocarbons that have the highest hydrogen contents ({approx_gt} 17wt %) and therefore require the least degree of polarization to be interesting. This present note summarizes the subsequent work done, to date, exploring some of the issues related to the chemical doping method. The main areas of progress have been in the literature search, experimental results on glass formation by alkanes, and a polarizing test of a ``prototype`` hydrocarbon.

1993-03-24

350

British Library Electronic Table of Contents (United Kingdom)

Dopant-free Bi2Ti2O7 thin films with pyrochlore structure and La-doped bismuth titanate thin films have been fabricated by means of chemical solution decomposition, and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy and UV?Vis spectrophotometry in this study. Their photocatalytic activities have been evaluated by photodegrading methyl orange solution, and the optimum processing parameters for the highest photocatalytic activity have been found. Moreover, the effects of La-doping on the phase transformation and the photocalalytic activity have been studied. It has been deduced from the experiment result that substituted La3+ ions can act as a stabilizer of Aurivillus phase BLT and a grain?growth inhibitor in BLT thin films.

2008-01-01

351

Performance improvement of quantum dot infrared photodetectors through modeling

British Library Electronic Table of Contents (United Kingdom)

This paper presents a method to evaluate and improve the performance of quantum dot infrared photodetectors (QDIPs). We proposed a device model for QDIPs. The developed model accounts for the self-consistent potential distribution, features of the electron capture and transport in realistic QDIPs in dark and illumination conditions. This model taking the effect of donor charges on the spatial distribution of the electric potential in the QDIP active region. The model is used for the calculation of the dark current, photocurrent and detectivity as a function of the structural parameters such as applied voltage, doping QD density, QD layers, and temperature. It explains strong sensitivity of dark current to the density of QDs and the doping level of the active region. In order to confirm our...

2010-01-01

352

Optical properties and up-conversion of Pr"3"+ doped CdS nanoparticles in sol-gel glasses

On character of organic additives effect on pitting corrosion rate of steel-Kh25T at various potentials

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.

2010-10-01

353

Occurence of active layer optical properties on some Lasing characteristics dye-doped Ch LC

The dependence of the inhibiting action of some surface active organic substances (SAOS) on the pitting- formation potential epsilonsub(p) has been investigated for the steel Kh25T. The study has been performed by potentiostatic method using the H_2SO_4 0.1-n-solution doped by NaCl, Na_2SO_4, in the presence of SAOS of different classes. As epsilonsub(p) shifts in positive direction from +0.6 to +1.1 V, the inhibiting action of the SAOS series (o-oxyquinoline) increases gradually till some critical potential above which SAOS favour pitting destruction of steel. This phenomenon should be considered in anodic protection in SAOS-doped solutions.

354

Mechanical Properties and Thermal Shock Resistance of Refractory Self-Reinforced -SiAlONs Using Barium Aluminosilicate as an Additive

Effect of a planar texture quality and its thickness on lasing spectrums and thresholds in dye-doped cholesteric liquid crystal (CLC) of steroid type is explored. Transition from the qualitative planar texture to the poor texture quality is accompanied by change of characteristic mode structures and by shift of barycentre in the long-wave side and the considerable growth of the lasing threshold. It is found that in the CLC texture created by substrates with perpendicular directions of orientation the stable single-mode lasing takes place. The nature of oscillated modes in such texture is caused by phase jump. The gained results show that in steroid CLC, unlike induced one, lasing spectrums is possible to feature with the coupled wave model. Key words: steroidal cholesteric liquid crystal, distributed feedback lasing, oscillation thresholds, phase defect of periodical structure, transmission and lasing spectra

2010-01-01

355

British Library Electronic Table of Contents (United Kingdom)

Yb-, Y-, Yb/Y-, and Yb/Nd-doped -SiAlON ceramics with 5-wt% barium aluminosilicate (BAS) were synthesized by hot pressing. Typical self-reinforced microstructures were obtained in all investigated -SiAlONs in spite of the type of doped cations. This is attributed to the incorporation of BAS, which could supply suitable liquid phase to promote the anisotropic growth of the -SiAlON grains. All the composites exhibited excellent high-temperature mechanical properties and thermal shock resistance due to the formation of a self-reinforced microstructure and the complete crystallization of BAS additive.

2011-01-01

356

Materials aspects of multijunction solar cells

Layer-by-layer assembly of functional silica and Au nanoparticles for fabricating electrogenerated chemiluminescence sensor

Atomic layer epitaxy (ALE) was used to grow several components of the cascade solar cell structure in the AlGaAs/GaAs system. An ALE reactor was constructed for multiwafer growth with a growth rate of 0.6 {mu}m h{sup -1}. Device quality GaAs and Al{sub x}Ga{sub 1-x}As films were grown with p-type background carbon doping in the ranges 10{sup 16}-10{sup 19} cm{sup -3} and 10{sup 16}-10{sup 20} cm{sup -3} respectively. N-type films were achieved by SiH{sub 4} doping, producing carrier concentrations in the range 10{sup 16}-10{sup 18} cm{sup -3}. In addition, the potential applications of the ALE technique in the photovoltaic field are discussed. (orig.).

1991-05-01

357

Layer-by-layer assembly of functional silica and Au nanoparticles for fabricating electrogenerated chemiluminescence sensor

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

2008-09-20

358

Layer-by-layer assembly of functional silica and Au nanoparticles for fabricating electrogenerated chemiluminescence sensor

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.

2008-09-20

359

British Library Electronic Table of Contents (United Kingdom)

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

2008-01-01

360

Investigation into #beta##reversible##omega#-transformation in pseudo -#beta# -titanium VT30 alloy, doped with hydrogen

Internal friction of amorphous Pd/sub 80/ Si/sub 20/ metal doped with hydrogen isotopes

To study #beta# #reversible# #omega#-transformation in pseudo-#beta#-titanium alloy VT30, doped by hydrogen, methods of X-ray diffraction and thermodifferential analyses are used. It is established that in the process of heating of the hardened alloy from 0.004-0.1% H first formation and then dissolution of #omega# phase take place. An increase in hydrogen content to 0.1% decreases thermal effect of the processes and does not affect the temperature of #beta# #reversible# #omega#-transformation. Introduction of hydrogen in the concentration of 0.2% and higher suppresses completely #beta# #reversible# #omega# - transformation. A decrease in heating rate displaces #beta# #reversible# #omega#-transformation to lower temperatures.

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361

Injection control and thermally stimulated current in ionic polarized polymer based light emitting diode

Internal friction of amorphous Pd/sub 80/Si/sub 20/ metal doped with hydrogen or deuterium was measured with a specially designed apparatus using amorphous metal sheet as a part of the electric oscillating circuit. Two peaks in Q/sup -1/ curve are observed. Applying the peak shift method to the first Snoek-like peak, we can determine the relaxation time from which the microdiffusion coefficient can be calculated. The obtained microdiffusion coefficient is about 10/sup -14/ m/sup 2//s at 200 K, being comparable with the macrodiffusion coefficient obtained from the releasing method. It can, however, not elucidate the hydrogen isotopic effect on the peak temperature of Q/sup -1/ curve, the activation energy for relaxation and the relaxation time from the present work because of the broadness of obtained Q/sup -1/ curve.

1983-02-01

362

Influence of self-doped poly(aniline-co-4-amino-3-hydroxy-naphthalene-1-sulfonic acid) on corrosion inhibition behaviour of iron in acidic medium

An effective method of enhancing charge injection and electroluminescence efficiency of polymer-based light emitting diode is introduced. Spin-coated films of poly (N-vinylcarbazole) blended with electron-transport material (Bu-PBD), laser dye (Coumarin6), and the typical supporting electrolyte (tetraethylammonium perchlorate; TEAP) were examined and it was found that the injection current and luminance of the light emitting diode doped with TEAP were enhanced dramatically after heat-treatment at 80 deg. C and appropriate biasing in an external electric field of 1.5x10"8 V/m at this temperature. The thermally stimulated current (TSC) was also measured to investigate the relaxation process of ionic space charges in the films. The relaxation times of ionic polarization were found to be related to the cation size of the electrolyte. And the relaxation time becomes long enough by the use of TEAP doping.

2003-08-22

363

British Library Electronic Table of Contents (United Kingdom)

This paper presents the corrosion inhibition performance of soluble self-doped copolymers of aniline and 4-amino-3-hydroxy-naphthalene-1-sulfonic acid synthesized by chemical oxidative polymerization method. The corrosion inhibition behaviour of the copolymers in 1.0M HCl has been evaluated using Tafel Extrapolation method and electrochemical impedance spectroscopy (EIS) which was also used to propose the mechanism besides surface morphology. The results showed that the copolymer film exhibited the significant shifting in the corrosion potential and greater charge transfer resistance. The corrosion inhibition efficiency was found to increase from 50% to 90% by increasing the concentration of copolymer from 10 to 70mg/l in HCl medium. Moreover, the copolymer showed the larger degree of surf...

2011-01-01

364

I. Evaluation of thin Pd, Pt and Ni silicides Schottky barriers for silicon solar cells. II. Large-area uniform growth of Si layer by solid-phase epitaxy. Final report

Flexible, all-organic ammonia sensor based on dodecylbenzene sulfonic acid-doped polyaniline films

Stability and decomposition of PtSi, NiSi, and PdSi in contact with single crystal or amorphous Si is examined. PtSi, PdSi and NiSi are thermally stable both with Si, but are unstable in contact with metal film. It is shown that epitaxial Si layers can be obtained using both Pd and Al as metal film and layers can be electrically doped by the addition of a doping layer to the thin film structure prior to the heat treatment or by inclusion of Al atoms so that n/sup +/ and p/sup +/ conductivity can be achieved in the grown epilayer. The effects of impurities, substrate orientation on the growth kinetics are also discussed. (LEW)

1981-01-01

365

Enhancement in transition temperature and upper critical field of CeO0.8F0.2FeAs by yttrium doping

A stable chlorobenzene dispersion of conducting polyaniline (PANI) has been obtained by doping emeraldine base with dodecylbenzene sulfonic acid (DBSA) and studied by spectrophotometric measurements in the UV-vis-IR range. The electrical properties of PANI: DBSA films obtained from the above dispersion have been investigated under different temperature and relative humidity conditions. All-organic chemoresistive devices have been developed by spin-coating the PANI: DBSA dispersion on flexible substrates, and then by depositing electrodes on the top, from a carbon nanotube conducting ink. Sensing tests performed under exposition to calibrated amounts of ammonia reveal that these simple and inexpensive sensors are able to detect ammonia at room temperature in a reliable way, with a sensitivity linearly related to concentration in the range between 5 ppm and 70 ppm.

2010-09-30

366

Electrogenerated chemiluminescence sensor for itopride with Ru(bpy)32+-doped silica nanoparticles/chitosan composite films modified electrode

We report significant enhancement in superconducting properties of yttrium substituted Ce1-xYxOFFeAs superconductors. The polycrystalline samples were prepared by two step solid state reaction technique. X-ray diffraction confirmed tetragonal ZrCuSiAs structure with decrease in both a and c lattice parameters on increasing yttrium substitution (with fixed F content). With smaller ion Y in place of Ce, the transition temperature increased by 6 K. Yttrium doping also lead to higher critical fields as well as broader magnetization loops, particularly at elevated temperature.

2009-12-01

367

British Library Electronic Table of Contents (United Kingdom)

A electrogenerated chemiluminescence (ECL) sensor for itopride was developed based on tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy)32+)-doped silica (RuDS) nanoparticles/biopolymer chitosan composites membrane modified glassy carbon electrode (GCE). The RuDS nanoparticles (52+-5nm) were prepared by a modified Stber synthesis method and were characterized by electrochemical, fluorometric and transmission electron microscopy technology. 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 ECL analytical performances of this ECL sensor for itopride based on its enhancement ECL emission of Ru(bpy)32+ were investigated in d...

2008-01-01

368

Electrical properties of antimony doped PLZT ceramics prepared by mixed-oxide route

Collection of athermal phonons into doped Ge thermistors using quasiparticle trapping

Ferroelectric [Pb_0_._9_2(La_1_-_zSb _z)_0_._0_8][Zr_0_._6_0Ti_0_._4_0]O_3 for z = 0.0, 0.3, 0.6, 0.9 and 1 were prepared from their constituent oxides by a solid state reaction technique. The powders were calcined in the temperature range of 1000 deg. C for 6 h. Phase formation, crystal structure and lattice parameter were investigated by X-ray diffraction (XRD) technique. The compacts were sintered at 1250 deg. C for 2 h and their dielectric, ferroelectric and conductive properties were measured. The ferroelectric behavior of the doped samples was studied from their hysteresis loop.

2006-12-21

369

Application of neutron transmutation doping method to initially p-type silicon material

We have developed a low-temperature particle detector that uses a novel quasiparticle trapping mechanism to funnel athermal phonon energy from an 80 mg Ge absorber into a 1.6 mg doped Ge thermistor via a superconducting Al film. We report on pulse height spectra obtained at 320 mK by scanning a {sup 241}Am alpha source along the device, and show that up to 20% of the energy deposited in the Ge absorber by a 5.5 MeV alpha particle interaction can be collected into a thermistor via quasiparticle trapping. We show that this device is sensitive to the position of an alpha particle interaction in the Ge absorber for interaction distances of up to 5 mm from a quasiparticle trap.

1995-05-15

370

British Library Electronic Table of Contents (United Kingdom)

The neutron transmutation doping (NTD) method was applied to the initially p-type silicon in order to extend the NTD applications at HANARO. The relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material was investigated. The proportional constant between the neutron fluence and the resistivity was determined to be 2.3473x1019ncm-1. The deviation of the final resistivity from the target for almost all the irradiation results of the initially p-type silicon ingots was at a range from -5% to 2%. In addition, the burn-up effect of the boron impurities, the residual 32P activity and the effect of the compensation characteristics for the initially p-type silicon were studied. Conclusively, the practical methodology to perform the neut...

2009-01-01

371

/sup 109/Ag NMR spectra of aqueous silver ions coordinated with nitroxide radical. Silver-TANOL complex and TANOL as a doping agent

Wool-waste as organic nutrient source for container-grown plants

The effects of TANOL radical have been examined on chemical shifts and relaxation rates of /sup 109/Ag NMR in aqueous solution of silver salts. The silver ion in aqueous solution is found to coordinate with TANOL radical. A small amount of TANOL is added as a doping agent(0.020M), since /sup 109/Ag signals are obtained for (1.0M) silver ion within 30 minutes. The /sup 109/Ag chemical shifts of silver salt in aqueous solutions were found within the range of 0 to -1000 ppm relative to that of 1.0M AgNo/sub 3/.

1982-09-01

372

Wear resistant composite structure of vitreous carbon containing convoluted fibers. Final report

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and ...

2009-07-01

373

Studies of optical properties and applications of some mixed ternary semiconductors

Energy Related Inventions Program Number 613 was a two year program to commercialize a unique new wear material, Metal Reinforced Carbon Composite, MRCC. The program was designed to manufacture sample components of MRCC for evaluation by potential users and manufacturers. As a result of the program Burton Technologies Inc. and Rotary Power International are forming a joint company to manufacture, market and license MRCC materials to a wide range of industries.

1996-05-28

374

Solar effects on communications

Refractive indices of some mixed compound semiconductors below the bandgap are presented on the basis of some fundamental parameters and the effect of lattice mismatch on the refractive index step is also studied. The results help to design a variety of opto-electronic devices for the use in optical fiber communication and heterostructure lasers. The calculated values agree well with available experimental values thus justifying the approach. (author).

375

Kevlar and carbon composites compared

This paper focuses on potential effects of solar phenomena on communication systems used by the electric utility industry. It begins with a discussion of solar phenomena fundamentals and discussion of the interaction between solar emissions and the earth's ionosphere and magnetosphere. It continues with a discussion of the resulting impacts on communication systems including radio, satellite, wireline, fiber optic, and powerline systems and concludes with a discussion of mitigation techniques and a call for observers to report suspected solar impact experiencexperiences.

376

Distribution and threshold expression of the tRNA(Lys) mutation in skeletal muscle of patients with myoclonic epilepsy and ragged-red fibers (MERRF).

Characteristics of advanced composites are investigated. The fibers considered are Kevlar and carbon. The greatest advantage of composites over metals is emphasized, and lies in their permitting designers to obtain properties in exactly the locations desired. Kevlar replaced S-glass on the Trident 2 missile, saving 800 lbs. and adding 800 miles to its range. Military aircraft builders find that advanced carbon composites more often than not win out over Kevlar.

1985-02-01

377

Development and characterization of carbon-bonded carbon fiber insulation for radioisotope space power systems

We investigated the distribution and expression of mutant mtDNAs carrying the A-to-G mutation at position 8344 in the tRNA(Lys) gene in the skeletal muscle of four patients with myoclonus epilepsy and...Full Text Available

1992-12-01

378

DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

The General-Purpose Heat Source (GPHS), an improved radioisotope heat source, employs a unique thermal insulation material, carbon-bonded carbon fiber (CBCF), to protect the fuel capsule and to help achieve the highest possible specific power. The CBCF insulation is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF shapes, both tubes and plates, are formed in a multiple molding facility by vacuum molding a water slurry of the carbonized chopped-rayon fiber (54 wt %) and phenolic resin (46 wt %). The molded shapes are subsequently dried and cured. Final carbonization of the resin is at 1600/sup 0/C. Machining to close tolerances (+-0.08 mm) is accomplished by conventional tooling and fixturing. The resulting material is an excellent lightweight insulation with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity ...

1985-06-01

379

Clinical translation of ultraviolet autofluorescence microscopy towards endomicroscopy for early detection of cancer

The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. During this reporting period, efforts have focused on the facility modifications for continuous hydrotreating, as well as developing improved protocols for producing synthetic pitches.

2005-08-11

380

CFCC radiant burner assessment. Final report, April 1, 1992--July 31, 1994

The non-invasiveness of autofluorescence technology may reduce sampling error and time delay for histopathology diagnosis. We establish biophotonic methods and guidelines to visualize and interpret early epithelial tissue changes that signify disease. Flexible and rigid fiber endomicroscopy instrumentation design parameters feasible for translation towards clinical use are in development.

2010-12-01

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381

In vitro MRI of brain development

The objective of this work was to identify methods of improving the performance of gas-fired radiant burners through the use of Continuous Fiber Ceramic Composites (CFCCs). Methods have been identified to improve the price and performance characteristics of the porous surface burner. Results are described.

1994-11-01

382

The rare earth antimonates: spectroscopic properties, crystal field and paramagnetic susceptibility simulations

In this review, we demonstrate the developmental appearance, structural features, and reorganization of transient cerebral zones and structures in the human fetal brain using a correlative histological and MRI analysis. The analysis of postmortem aldehyde-fixed specimens (age range: 10 postovulatory weeks to term) revealed that, at 10 postovulatory weeks, the cerebral wall already has a trilaminar appearance and consists of: (1) a ventricular zone of high cell-packing density; (2) an intermediate zone; (3) the cortical plate (in a stage of primary consolidation) with high MRI signal intensity. The anlage of the hippocampus is present as a prominent bulging in the thin limbic telencephalon. The early fetal telencephalon impar also contains the first commissural fibers and fornix bundles in the septal area. The ganglionic eminence is clearly visible as an expanded continuation of the proliferative ventricular zone. The basal ganglia showed an initial aggregation of ...

2006-02-01

383

The effects of helium on the embrittlement and hardening of boron doped EUROFER97 steels

The rare earth antimonates RE_3Sb_5O_1_2 constitute an isostructural series, where the rare earth site symmetry is S_4. The spectroscopic properties of pure or doped compounds of this family are studied in order to derive their energy level schemes and to simulate them through the crystal field theory, by using the approximated D_2_d potential. The paramagnetic susceptibilities are calculated with the derived wavefunctions and compared to experiment.

1990-09-01

384

Suppression of afterglow in CsI:Tl by co doping with Eu"2"+-II: Theoretical model

The role of helium in a process of embrittlement and hardening of RAFM steels was investigated in EUROFER97 based experimental heats, ADS2, ADS3 and ADS4, that were doped with different contents of natural B and the separated 10B-isotope (0.008-0.112 wt.%). The neutron irradiation of the boron doped and the reference RAFM steels was performed in the Petten High Flux Reactor up to 16.3 dpa at different temperatures between 250 and 450 deg. C. The embrittlement behaviour and hardening was investigated by instrumented Charpy-V tests with subsize specimens. Irradiation lead to generation of 84, 432 and 5580 appm He in ADS2, ADS3 and ADS4 steels, respectively. At irradiation temperatures Tirr ? 350 deg. C the boron doped steals show progressive embrittlement and reduction of toughness with increasing helium amount. The analysis of the hardening vs. embrittlement behaviour at Tirr ? 350 deg. C reveals hardening nature of ...

2008-12-01

385

Spin fluctuation changes in Ge doped YbPd_2Si_2

The mechanism for afterglow suppression in codoped CsI:Tl,Eu reported in the preceding paper was investigated by combined radioluminescence and thermoluminescence experiments. Model rate equations informed by these experiments were employed to simulate afterglow. It was found that codoping with europium introduces deep electron traps, with room-temperature glow peaks, that effectively scavenge the electrons from shallow traps associated with thallium, thus suppressing afterglow in the time domain of tens of milliseconds.

2006-03-15

386

Spectral analysis of Pr3+-, Sm3+- and Dy3+-doped transparent GeO2-BaO-TiO2 glass ceramics

In YbPd_2Si_2, the valence of Yb is very close to 3+. Ge substitution of Si induces a negative pressure effect and the valence of Yb decreases. For the low Ge concentrations studied, the spin fluctuation temperature T_s_f increases and #chi#4f, the Yb derived 4f susceptibility, obeys the scaling law #chi#4f(T)=F(T/T_s_f). (orig.).

387

British Library Electronic Table of Contents (United Kingdom)

In this paper, we present the photoluminescence properties of Pr3+-, Sm3+- and Dy3+-doped germanate glasses and glass ceramics. From the X-ray diffraction measurement, the host glass structure was determined. These glasses have shown strong absorption bands in the near-infrared (NIR) region. Compared to Pr3+-, Sm3+- and Dy3+-doped glasses, their respective glass ceramics have shown stronger emissions due to the Ba2TiGe2O8 crystalline phase. For Pr3+-doped glass and glass ceramic, emission bands centered at 530nm (3P03H5), 614nm (3P03H6), 647nm (3P03F2) and 686nm (3P03F3) have been observed with 485nm (3H43P0) excitation wavelength. Of them, 647nm (3P03F2) has shown bright red emission. Emission bands of 4G5/26H5/2 (565nm), 4G5/26H7/2 (602nm) and 4G5/26H9/2 (648nm) for the Sm3+:glass and gl...

2009-01-01

388

Simulation of arsenic diffusion during rapid thermal annealing of silicon layers doped with low-energy high-dose ion implantation

Simulation aided hardening of N-channel power MOSFETs to prevent single event burnout

The model of transient enhanced diffusion of ion-implanted As is formulated and the finite-difference method for numerical solution of the system of equations obtained is developed. The nonuniform distribution of point defects near the interface and more accurate description of arsenic clustering are simultaneously taken into account. Simulation of As diffusion during rapid annealing gives a reasonable agreement with the experimental data. (authors)

2005-09-01

389

STM studies of CDWs in pure and doped transition metal chalcogenides

2D MEDICI simulator is used to investigate hardening solutions to single-event burnout (SEB). SEB parametric dependencies such as carrier lifetime reduction, base enlargement, and emitter doping decrease have been verified and a p"+ plug modification approach for SEB hardening of power MOSFETs is validated with simulations on actual device structures.

1995-07-17

390

Residual #alpha#-Si_3N_4 in O' crystals in CeO_2-doped O' + #beta#' SiAlON ceramics

The effects of dilute impurity doping on charge-density wave (CDW) structures and gaps in NbSe{sub 3} 1T-TaS{sub 2} and 2H-NbSe{sub 2} have been studied by using a scanning tunneling microscope (STM) operating at 4.2 K. In Fe doped samples of NbSe{sub 3} the STM spectroscopy measurements indicate that the added impurities can significantly shift the CDW energy gaps. In NbSe{sub 3}, Fe reduces both CDW gaps by 25-30%, and produces changes in the conductance structure relative to the pure material. The images of Fe{sub 0.01}NbSe{sub 3} show that all three surface chains in the unit cell still carry a strong CDW modulation with no evident disorder. However, a change in the relative amplitudes of the high and low temperature CDWs is detected. The effects of Co and Ni impurities on the gaps in NbSe{sub 3} have also been studied. While Co increases both by 25-30%, Ni increases only the high temperature gap with the low temperature gap remaining ...

1992-12-01

391

Photooxidation of different organic dyes (RB, MO, TB, and BG) using Fe(III)-doped TiO{sub 2} nanophotocatalyst prepared by novel chemical method

The microstructure of a pressureless sintered (1,605 C, 90 min) O' + #beta#' SiAlON ceramic with CeO_2 doping has been investigated. It is duplex in nature, consisting of very large, slablike elongated O' grains (20--30 #mu#m long), and a continuous matrix of small rodlike #beta#' grains (< 1.0 #mu#m in length). Many #alpha#-Si_3N_4 inclusions (0.1--0.5 #mu#m in size) were found in the large O' grains. CeO_2-doping and its high doping level as well as the high Al_2O_3 concentration were thought to be the main reasons for accelerating the reaction between the #alpha#-Si_3N_4 and the Si-Al-O-N liquid to precipitate O'-SiAlON. This caused the supergrowth of O' grains. The rapid growth of O' crystals isolated the remnant #alpha#-Si_3N_4 from the reacting liquid, resulting in a delay in the #alpha# #-># #beta#-Si_3N_4 transformation. The large O' grains and the #alpha#-Si_3N_4 inclusions have a pronounced effect on the ...

392

Peculiarities of #beta#-solid solution decomposition in (#alpha#+#beta#) titanium alloy at low temperature

The nano-structured Fe(III)-doped TiO{sub 2} photocatalysts with anatase phase have been developed for the oxidation of non-biodegradable different organic dyes like methyl orange (MO), rhodamine B (RB), thymol blue (TB) and bromocresol green (BG) using UV-Hg-lamp. The different compositions of Fe{sub x}Ti{sub 1-x}O{sub 2} (x = 0.005, 0.01, 0.05, and 0.1) nanocatalysts synthesized by chemical method (CM), have been characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, specific surface area (BET), transmission electronic microscopy (TEM) analysis, XPS, ESR and zeta potential. From XRD analysis, the results indicate that all the compositions of Fe(III) doped in TiO{sub 2} catalysts gives only anatase phase not rutile phase. For complete degradation of all the solutions of the dyes (MO, RB, TB, and BG), the composition with x = 0.005 is more photoactive compared all other compositions of Fe{sub x}Ti{sub 1-x}O{sub 2}, and ...

2008-09-15

393

Nonformity of the electron density in amorphous silicon films

The physical methods were used to study the decomposition of a metastable #beta#-solid solution in the VT22 two-phase titanium alloy. It is shown that the martensitic #beta# #-># #alpha#'' transformation in doped-element depleted microvolumes of the #beta#-solid solution are dominanted and the long-time multistage decomposition through a number of intermediate states in others.

394

New crystals for dual-readout calorimetry

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

1985-12-01

395

Nanocrystalline doped cerium oxide as a catalyst for SO{sub 2} reduction by CO

Lead tungstate crystals doped with small fractions of praesodynium or molybdenum have been tested in beams of high-energy electrons. The goal of these tests was to study the effects of such dopants on the capability to separate the signal components deriving from the Cherenkov and scintillation light generated by the beam particles. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.

2009-01-01

396

Intrinsic and extrinsic crossluminescence in ionic crystals

Nanocrystalline processing by inert gas condensation has the inherent advantages of generating: (1) high surface area nanoclusters, (2) non-stoichiometric oxides, and (3) high dispersions of dopants. This approach is exploited in the synthesis of fluorite-structured catalysts for SO{sub 2} reduction by CO. Nanocrystalline CeO{sub 2{minus}x}, La-doped CeO{sub 2{minus}x}, and Cu-doped CeO{sub 2{minus}x} were produced by magnetron sputtering from a pure or mixed metal target, followed by controlled oxidation of the metallic clusters. The as-prepared doped and undoped nanocrystalline CeO{sub 2{minus}x} materials were found to be excellent catalysts for complete SO{sub 2} conversion to elemental sulfur. Undoped nanocrystalline CeO{sub 2{minus}x} enabled light-off at 460 C, a temperature {approximately} 120 C lower than that over polycrystalline CeO{sub 2}, which is a novel effective catalyst itself. The high catalytic activity ...

1994-12-31

397

Intrinsic and extrinsic crossluminescence in ionic crystals

Intrinsic crossluminescence (CRL) of CsBr, CsCl, and of BaF{sub 2} was investigated with electron-beam and synchrotron radiation excitation. From the CRL spectra, the excitation spectra and the reflectivity, energy level schemes were deduced. Extrinsic CRL was observed changing either the initial (CsCl:Br{sup -}) or the final (RbCl:Cs{sup +}; KCl:Cs{sup +}) state of CRL by doping. (author).

1991-01-01

398

Hydrogen effect or texture and deformation mechanism in #beta#-titanium alloy cold rolling

Intrinsic crossluminescence (CRL) of CsBr, CsCl, and of BaF_2 was investigated with electron-beam and synchrotron radiation excitation. From the CRL spectra, the excitation spectra and the reflectivity, energy level schemes were deduced. Extrinsic CRL was observed changing either the initial (CsCl:Br"-) or the final (RbCl:Cs"+; KCl:Cs"+) state of CRL by doping. (author).

1990-09-03

399

High-temperature ferromagnetism in laser-deposited layers of silicon and germanium doped with manganese or iron impurities

The relationships of hydrogen alloyed #beta#-titanium alloy deformation behaviour to its microstructure and texture are investigated. It is shown that plasticity increases and strain induced texture changes at low hydrogen contents (0.1-0.2 mass %). Possible mechanisms responsible for specific features of #beta#-Ti alloy deformation are discussed. The study is made using alloy VT35 doped with hydrogen

1999-09-01

400

Facile synthesis and the sensitized luminescence of europium ions-doped titanate nanowires

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

2009-04-15

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401

Analysis of TL glow curves in differently doped LiF:Mg,Ti

Europium (Eu) ions-doped titanate nanowires were synthesized via a sol-gel-hydrothermal chemistry and they were found to be roll multilayered trititanate-type nanowires intercalated with Eu3+ and alkali ions. The average diameter was about 20 nm for nanowires synthesized in NaOH solution and about 10 nm for nanowires synthesized in KOH solution. Under ultraviolet excitation the nanowires showed bright red emission corresponding to 5D0-7Fj of Eu3+ ions at room temperature, which was attributed to the non-radiative energy transfer from the surrounding Ti-O octahedral nanosheets to the central Eu3+ ions in interlayer. The luminescent properties of nanowires were influenced by the type of co-intercalated alkali ions, doping degree, hydrothermal and annealing temperatures. The intensity ratio of 5D0-7F2 to 5D0-7F1 of titanate nanowires intercalated with Eu3+ and Na+ ions was higher than that of titanate nanowires intercalated with Eu3+ and K+ ions. ...

2009-04-15

402

Sunlight photocatalytic activity of CdS modified TiO2 loaded on activated carbon fibers

A computerised curve-fitting method was developed to calculate the trapping parameters in LiF TLD-100 and LiF:Mg, Ti. After irradiation in a "6"0Co field and with X rays emitted at different voltages the TL process is best described by first-order kinetics. A dependence of the trapping parameters on both the concentration of Mg and Ti and photon energy was detected. (author).

403

British Library Electronic Table of Contents (United Kingdom)

To improve the photocatalytic application performances of TiO2, in this work, firstly CdS modified Degussa P25 TiO2 (CdS/TiO2) composites were prepared by two methods, sol-gel method and precipitation method. Next they, sol-gel-CdS/TiO2 (sg-CdS/TiO2) and precipitation-CdS/TiO2 (pp-CdS/TiO2), were loaded on activated carbon fibers (ACFs) by dip-coating method using the sodium carboxymethyl cellulose as adhesives. The composites were characterized by XRD, UV-vis absorbance spectra, SEM, EDS and BET. The photocatalytic activities under sunlight were investigated by the degradation of methylene blue. The results showed that CdS/TiO2 composites were mainly composed of anatase-TiO2 and little CdS cubic phases. The absorption wavelengths of sg-CdS/TiO2 and pp-CdS/TiO2 composites were extended to ...

2010-01-01

404

Self-lubricating performance and durability of ball bearings for the LE-7 liquid oxygen rocket-turbopump

Radiosynthesis of hydrogel confined to hollow-fiber membranes for the design of a bioartificial extra-corporeal liver

The durability of ball bearings, 32-mm- and 45-mm-bore, with a retainer or glass cloth-polytetrafluoroethylene (PTFE) laminate was tested under a high radial load at a speed of 20,000 rpm in LOX or LN2. The retainers were characterized as good self-lubricators because the abrasive glass-cloth fiber tips exposed on the retainer were chemicaly etched away with hydrofluoric acid (HF). During testing, the bearing-cartridge-acceleration was monitored to detect bearing damage. Testing in LOX for about 2.2 hr showed that excellent lubricating conditions were obtained for all bearings. Testing in LN2 for about 5.1 hr detected that the fatigue life of the bearing was about the same as the calculated B10 fatigue life. The HF chemical treatment resulted in a reacted fluoride-oxide material which remained in the etched part of the glass fiber. Several chemical products, particularly MgO, CaO, and CaCO3, enhanced adhesion of PTFE transfer film to the ...

1993-09-01

405

Radiation processing of wood-plastic composites

Current bioartificial extra-corporeal systems are bioreactors where cells are separated from the surrounding media by porous polymeric membranes. The present work focuses on the design of membranes that allow the differential diffusion of plasma metabolites and proteins such as immunoglobulin (IgG). This design will improve catabolites removal and reduce possible immune response and virus infection. We demonstrate the feasibility to synthesize the hydrogels confined to the macroporous structure of membranes by radiation-induced in situ polymerization. The hollow-fiber membranes were soaked in aqueous monomeric solution, rinsed and irradiated while submerged in oil. This procedure confined the hydrogel to the void internal volume of the pores of the membrane. Hydrogels of polyacrylamide and polyHEMA were synthesized this way by irradiation at 10 kGy. Hydraulic permeability and diffusion of glucose, albumin and IgG were measured in these hydrogel-filled membranes. ...

2007-08-15

406

Radiation hardness of plastic scintillating fiber against fast neutron and #gamma#-ray irradiation

There are three main types of radiation-processed composite material derived from plastics and fibrous natural polymers. The first are the monomer-impregnated, radiation-treated wood-plastic composites (WPC). They became a commercial success in the early 1970s. More recently, work has focused on improving the WPCs by creating in them interpenetrating network (IPN) systems by the use of appropriate multifunctional oligomers and monomers. The main kinetic features of radiation-initiated chain polymerization remain applicable even in impregnated wood. The second type are the plastics filled or reinforced with dispersed wood fiber or other cellulosics (WFRP). In their case, radiation processing offers a new opportunity to apply radiation-reactive adhesion promoters between wood or cellulosic fibers and the thermoplastic matrices. The third type are the laminar composites made by electron beam coating of wood-based agglomerate sheets and boards. ...

407

Principe local-global pour les z\\'ero-cycles sur certaines fibrations au-dessus d'une courbe: II

In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10"2 #approx# 10"5 Gy/yr and 10"1"1 #approx# 10"1"4 n/cm"2/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be resistive against high radiation levels. From this point of view, it is of great importance to study the effects of radiation damage on the performance of the detectors. The authors report preliminary results of measurements of radiation hardness of the plastic scintillating fiber Kuraray SCSF-81 against irradiation with fast neutrons and "6"0Co #gamma#-rays in the region of the neutron fluence from 1 x 10"1"1 to 5 x 10"1"3 n/cm"2 and the integrated #gamma#-ray dose from 890 to 10"5 Gy, respectively. Deterioration of both intrinsic light yield and light transmittance of the SCSF-81 has been studied.

1992-10-25

408

Optoelectronic multipoint liquid level sensor for light petrochemical products

We consider an admissible fibration $\\pi:X\\to\\mathbb{P}^1$ over a curve over a number field, of which the generic fiber $X_\\eta$ is geometrically rationally connected. We suppose that there exists a generalized Hilbertian subset $\\textsf{Hil}$ of $\\mathbb{P}^1$, such that the Brauer-Manin obstruction is the only obstruction to the Hasse principle (resp. to the weak approximation) for $X_\\theta(\\theta\\in \\textsf{Hil}).$ We prove that the Brauer-Manin obstruction is the only obstruction to the Hasse principle (resp. to the strong approximation) for zero-cycles of degree 1 on $X$ in the following cases: $(B_1)$ the index of the generic fibre $X_\\eta$ is equal to 1; $(B_2)$ all fibers are geometrically integral. Then, we obtain some similar results for certain fibrations over $\\mathbb{P}^n$. As a consequence, we obtain the following result: let $X$ be a smooth projective geometrically rationally connected variety over a number field ...

2010-01-01

409

On-line analysis of chemical composition using an FT-Raman spectrometer in the near-ir

In this article we describe an optoelectronic sensor for assessing the level of light petrochemical products in technological tanks at the oil refineries. This sensor employs the multi-element vertical array of discrete micro- optical refractometric transducers. The transducers are made of silica glass and have the conical shape. In the air, each transducer operates as a tiny retro-reflector that optically couple together two multimode optical fibers. The optical coupling in the transducer is due to the internal reflection at the conical surface. The amount of the coupling depends on the refractive index of the surrounding media. In a fluid, the total internal reflection vanishes and the coupling becomes negligibly small. The number of immersed transducers is a measure of the fluid level in the reservoir. Because of the significance of the transducer transmission function, it is evaluated in detail under various combinations of the geometrical parameters of the ...

2000-06-01

410

On the bending response of Kevlar 49/epoxy beams and rings

Newly commercialized Fourier transform Raman spectroscopic instrumentation provides a simpler alternative for vibrational spectroscopic analysis. Instrument vendors currently design for laboratory use, but there are many potential process applications of these stable, easy to use instruments. Raman spectroscopy is highly suited to analysis of aqueous samples. Near infrared excitation minimized fluorescence interference and allows for remote operation via fiber optic probes. The Department of Energy has funded research at the Measurement and Control Center to establish the utility of this method for on-line composition analysis in distillation columns. Laboratory evaluation and instrument employs an air-cooled laser and a thermoelectrically cooled detector. The device is mounted on a three by foot cart for convenient location in control rooms. Current fiber optic extension cables allow for analysis in a cell thirty five meters from the ...

1992-01-01

411

Fundamentals for remote structural health monitoring of wind turbine blades - a pre-project. Annex D - Full-scale test of wind turbine blade, using sensors and NDT

Kevlar 49/epoxy laminates often exhibit substantial material nonlinearity when subjected to bending. This is a consequence of the yeild-like behavior of a Kevlar 49/epoxy lamina in fiber-directed compression. In this paper, analyses that utilize a simple idealization of compressive yielding are described and calculated results for Kevlar 49 reinforced beams and rings are compared with available data. First, results of a finite element analysis of a thin, unidirectionally reinforced ring subjected to diametral compression are presented. This analysis uses beam elements that incorporate linear tensile and elastic-perfectly plastic compressive behavior. Then a method used to analyze quasi-isotropic beams tested in four-point bending is discussed. This finite element analysis uses a layered shell element with a lamina constitutive model that permits elastic-perfectly plastic response to fiber-directed compression, but otherwise assumes linear ...

1988-05-01

412

Feasibility of optical sensing for robotics in highly radioactive environments

A 19.1 metre wind turbine blade was subjected to static tests. The purpose of the test series was to verify the abilities of different types of sensors to detect damage in wind turbine blades. Prior to each of the static test-series an artificial damage was made on the blade. The damage made for each test-series was surveyed during each series by acoustic emission, fiber optic micro bend displacement transducers and strain gauges. The propagation of the damage was determined by use of ultra sonic and X-ray surveillance during stops in the test series. By use of acoustic emission it was possible to measure damage propagation before the propagation was of visible size. By use of fiber optic micro bend displacement transducers and strain gauges it was possible to measure minor damage propagation. By use of both ultra sonic, and X-ray NDT-equipment it were possible to determine the size of propagated damage. (au)

2002-05-01

413

Electrospray deposition and direct patterning of polylactic acid nanofibrous microcapsules for tissue engineering.

The application of robotics for repair, refurbishing or dismantling of nuclear installations implies eventually severe radiation resistance requirements on embarked components and subsystems. This is particularly critical when optical sensing is considered. Optoelectronic components and optical fibers are indeed quite sensitive to radiation, and without special design are rapidly out-of-operation in such an environment. This paper reports the results of a series of #gamma# irradiation experiments on such devices, and identify their behavior under radiation. Test results show that carefully selected optical fibers can keep their radiation induced attenuation lower than 0.3 dB/m even up to a total dose of 10 MGy. Temperature annealing can even lower this attenuation down to 0.1 dB/m. On the other hand, commercially available light emitting diodes and photodiodes present attenuations figures up to 15 dB, even after a gamma irradiation as low as ...

1992-10-25

414

Development of polymeric coatings for submerse flexible lines; Desenvolvimento de revestimentos polimericos para linhas flexiveis submersas

Electrospun nanofibers composed of biodegradable polymers are attractive candidates for cell culture scaffolds in tissue engineering. Their fine-meshed structures, resembling natural extracellular matrices, effectively interact with cell surfaces and promote cell proliferation. The application of electrospinning, however, is limited to two-dimensional (2D) or single tube-like scaffolds, and the fabrication of arbitrary three-dimensional (3D) scaffolds from electrospun nanofibers is still very difficult due to the fibers' continuous and entangled form. To address this issue, in this paper, we describe the use of phase-separation-assisted electrospray and electrostatic focusing to perform continuous direct 3D patterning of nanofibrous microcapsules of biodegradable polylactic acid (PLA). These microcapsules exhibit fiber-particle duality because they are composed of nanofibers suitable for cell attachment while also being easy to handle as ...

2011-09-01

415

Composite electrode substrate for fuel cell requiring no separator plate and its production method; Separeta ban wo fuyo tosuru nenryo denchiyo fukugo denkyoku kiban oyobi sono seizoho

The major objective of this work is to seek for new solutions that can lead to significant lifetime improvement of submerse lines which experience severe wear processes on the polymeric layer coating used for protection of the touch down point (TDP) region. Four different materials were selected as possible candidates for the coating layer of this critical region. They are commercially available and posses well known processing technologies. The materials are two polymers: nylon 66 and polyacetal; and two composites: nylon 66 reinforced with 13 or 33% glass fiber. Stress-strain behavior was evaluated using two deformation rates in order to characterize the viscoelastic behavior proper of polymeric materials. It was observed that increasing the amount of glass fiber in the matrix leads to a stronger material and a consequent decrease of elongation to break. Additionally, abrasion tests were carried out using a Taber equipment in three distinct ...

2003-07-01

416

(Packaging regulations for chemical explosives)

This invention relates to the production method of composite electrode substrate for fuel cell. An impermeable material is used for edge sealant. The sealant is put in the clearance between two electrodes consisting of porous carbon material via thermoplastic resin sheet, and heated while being pressed. This production method increases the adherence between the porous carbon bodies and reduces the contact resistivity at the joint interface. Consequently, it becomes possible to produce the composite electrode for fuel cell without separator, resulting in simplification of assembly work, weight reduction, and downsizing. The preferable porous carbon body is made from shrinkage-treated fiber. After sheet forming, the thermosetting resin is impregnated, and then it is burnt to carbonization. Or mixed sheet of rayon and acrylic fiber is laminated to be heated and pressed without impregnating the resin. The pressed resin is then burnt to ...

1996-04-12

417

Visible and near-infrared spectral signatures for adulteration assessment of extra virgin olive oil

The purpose of the trip was to visit Nobel Chemicals in Sweden and to confer with the Department of Transportation personnel in Sweden and in England on the technical and regulatory problems in the bulk shipping of the high explosives RDX and HMX. It is customary in the United States (US) to add isopropyl alcohol to the bulk shipment of water-wet high explosives RDX and HMX. The explosives are packed in cloth bags which are placed in plastic-lined fiber drums. The addition of alcohol presumably prevents mildewing of cloth bags and freezing of the wet explosives in cold weather. In Europe, however, these explosives are shipped in polyethylene-lined fiber drums with not less than 15% water only, even in cold weather. Water-wet frozen explosives have not proved to be any more sensitive than its unfrozen counterpart and no mildew problem has been encountered. It looks promising that the US Department of Transportation regulations can be changed to ...

1988-02-17

418

The AMS-02 electromagnetic calorimeter

Because of its high price, the extra virgin olive oil is frequently target for adulteration with lower quality oils. This paper presents an innovative optical technique capable of quantifying the adulteration of extra virgin olive oil caused by lowergrade olive oils. It relies on spectral fingerprinting the test liquid by means of diffuse-light absorption spectroscopy carried out by optical fiber technology in the wide 400-1700 nm spectral range. Then, a smart multivariate processing of spectroscopic data is applied for immediate prediction of adulterant concentration.

2010-04-01

419

Study of the formation of polyethylene composites and lignocellulose materials by means of irradiation and extrusion

The Electromagnetic Calorimeter (ECAL) of the AMS-02 experiment is a lead-scintillating fibers sampling calorimeter characterized by high granularity that allows to image the longitudinal and lateral showers development, a key issue to provide high electron/hadron discrimination. The light collection system and the FE electronics are designed to let the calorimeter operate over a wide energy range from few GeV up to 1 TeV. A full-scale prototype of the e.m. calorimeter was tested at CERN in October 2001 using electrons and pions beams with energy ranging from 3 to 100 GeV. Effective sampling thickness, linearity and energy resolution were measured. (8 refs).

2002-01-01

420

Observation of stochastic resonance near a subcritical bifurcation

One of the greatest opportunities for using of biomass as a precursor in the production of polymeric materials is the lignocellulose composites that can combine high performance with low costs. This work is a initial study on the production of a lignocellulose reinforced polyethylene composite. A compatibilization made by a induced gamma radiation grafting reaction was used to increase the adhesion between the matrix and the reinforced or filled fibers. The lignocellulose materials were exposed to gamma radiation in order to promote a molecular degradation and increase its reactivity. The polymer, the lignocellulose material and the compatibilization were processed by extrusion and the composite produced by this process were characterized by mechanical tests. (author)

2000-10-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

421

Modeling and Experimental Study of Carbon Dioxide Absorption in a Membrane Contactor

A hysteretic subcritical period-doubling bifurcation is observed in the nonlinear strain dynamics of a magnetostrictive oscillator. The dynamic strain response of the magnetostrictive oscillator was observed with a high-resolution fiber optic interferometer. The effects of low-frequency modulation and band-limited stochastic fluctuations on such a bifurcation are investigated. Power spectral density measurements show that for an optimal value of externally injected noise the signal-to-noise ratio of a low-frequency modulation signal is enhanced by greater than 14 dB, thus indicating the first experimental observation of stochastic resonance near a bistable period-doubling bifurcation. 10 refs., 7 figs.

1993-01-01

422

Methodology for fabrication of hydraulics mini turbines with composite materials; Metodologia para a fabricacao de mini turbinas hidraulicas com materiais compostos

This dissertation deals with membrane gas absorption in the application of CO{sub 2} removal by aqueous alkanolamines, using microporous PTFE hollow fiber membranes. A new lab-scale apparatus was constructed and an extensive experimental study executed to determine the performance of the membrane gas absorber, with aqueous solutions of monoethanolamine (MEA) and methyldiethanolamine (MDEA) as absorbents. The important operation parameters CO{sub 2} partial pressure, gas velocity, liquid velocity, temperature and liquid CO{sub 2} loading were systematically varied within the range typically experienced in a process for exhaust gas CO{sub 2}-removal

2003-03-15

423

Innovative active control of gun barrels using smart materials

This paper presents the description of methodological procedure specially developed for manufacturing mini turbines. This procedure is used in the design of a Francis type mini turbine with 12.5 kW. The housing volute and the suction tube of this equipment are manufactured with using composed material based on glass fiber and its distributor system is manufactured with stainless steel and brass. At the end it is presented an estimate cost of design / manufacturing of such equipment and a comparison with other equipment in the market.

2009-07-01

424

Heat recovery in polyester production: a case study

The accuracy of stabilized, turreted gun systems like the 120mm gun on the M1A2 Abrams tank and the 30mm gun on the Apache helicopter are limited by, among other things, structural flexure of the gun barrel and support structure. An advanced actuation system based on piezoelectric translators and an optical fiber strain sensing system are described in conjunction with a rapid prototyping workstation for the design of distributed parameter control systems to actively minimize the effects of vibrations caused by traversing rough terrain or weapon firing.

1997-06-01

425

Endomicroscopy imaging of epithelial structures using tissue autofluorescence

Energy savings in the synthetic fiber industry could be realized by using autoclave reactor condensate and boiler flue gas heat recovery. The non-cellulose (polyester) production process analysis shows that condensate returning from the reactor to the steam boiler raises inlet temperature, giving a reduced fuel requirement of about 8%. Also, boiler flue gas with a sufficiently high outlet temperature for boiler feed water and combustion air preheating results in further fuel savings. The process with an economizer saves up to 8.44%, and with a combustion air preheater, 6.25%. (Author)

1997-07-01

426

Chandler Slavin | Greener Package

We explore autofluorescence endomicroscopy as a potential tool for real-time visualization of epithelial tissue microstructure and organization in a clinical setting. The design parameters are explored using two experimental systems--an Olympus Medical Systems Corp. stand-alone clinical prototype probe, and a custom built bench-top rigid fiber conduit prototype. Both systems entail ultraviolet excitation at 266 nm and/or 325 nm using compact laser sources. Preliminary results using ex vivo animal and human tissue specimens suggest that this technology can be translated toward in vivo application to address the need for real-time histology.

2011-04-01

427

Wastenet

...it only highlights the different feedstocks used in the production of fiber-based packaging materials or fossil-fuel ones; what about the energy required to convert ...feedstock, is unacceptable in trying to quantify the overall burden a specific packaging material has on the environment. As an aside, the point ... Consequentially, it is difficult to speculate on how much packaging material a company diverts from the landfill by switching from one material to another ...without specifying what geographical region said packaging material resides in. In addition, there is a lot of interest in diverting PET thermoforms from ...

428

Cadmium and endrin toxicity to fish in waters containing mineral fibers

Brittle fracture problem in composite insulators

Taconite tailings and their component asbestiform minerals in Lake Superior water had no demonstrable effect on the chronic toxicity of cadmium to the flagfish, Jordanella floridae. Maximum acceptable toxicant concentrations determined in life cycle tests, where effects on survival, growth, reproduction, and bioconcentration were used as endpoints, were between 3.3 to 7.4, 3.0 to 6.5, and 3.4 to 7.3 micrograms cadmium/liter at 0.004, 0.08, and 0.95 mg/liter taconite tailings concentrations, respectively.

1982-05-01

429

Application of fracture mechanics to cementitious composites

The report traces the documented incidences of brittle fracture in composite suspension insulators for use on high voltage transmission lines, and presents the subsequent investigations. It describes the part played by electrical activity, stress corrosion and humidity, and compares similar failures that have taken place in electric traction insulators. It then goes on to review related work on the humidity effects, stress corrosion, fatigue and partial discharges in glass fiber reinforced plastics in general. The final section summarizes the present understanding of the problem and the various measures taken by different manufactures to avoid it in the future. The need for acceptance criteria in this respect is outlined.

1984-04-01

430

Acute diaphragmatic paralysis caused by chest-tube trauma to phrenic nerve

This work contains 27 chapters which cover recent advances in fracture mechanics applied to cement-based composites: concrete, reinforced concrete, and fiber reinforced concrete. The book, based on a NATO Advanced Study Institute, is a comprehensive survey of treating nonlinearity associated with crack growth in brittle materials such as cement composites, rocks and ice. The book is divided into 8 major themes: advances in nonlinear fracture mechanics; fracture processes; numerical modelling of fracture; experimental methods of determining fracture parameters; damage and continuum modelling; strain-rate and dynamic effects of crack propagation; stress-corrosion, time and temperature effects on fracture; and implications for concrete structures.

1985-01-01

431

Report of the results of the fiscal 1997 regional consortium R and D project. Regional consortium energy field / R and D mesoscopic organ control heat-resistant / wear-resistant metal group composite materials (first fiscal year); 1997 nendo chiiki consortium kenkyu kaihatsu jigyo. Chiiki consortium energy bun`ya / mesoscopic fukuso soshiki seigyo tainetsu taimamosei kinzokuki fukugo zairyo no kenkyu kaihatsu (daiichi nendo) seika hokokusho

A 3"1/_2-year-old child developed unilateral diaphragmatic paralysis after chest drain insertion. Plain chest X-ray demonstrated paravertebral positioning of the chest-tube tip, and magnetic resonance imaging revealed hematomas in the region of the chest-tube tip and the phrenic nerve fibers. The trauma to the phrenic nerve was apparently secondary to malposition of the chest tube. This is a rare complication and has been reported mainly in neonates. Radiologists should notify the treating physicians that the correct position of a chest drain tip is at least 2 cm distant from the vertebrae. (orig.)

2001-06-01

432

Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

Out of the R and D of mesoscopic metal group composite materials, the paper described the fiscal 1997 results. In the in-situ method as a composite material making method, elucidated to some degree were chemical composition of Fe-C-Cr-V-Nb-Mo-W-Ni base multi-dimensional alloys, and wear resistance and oxidation resistance of MC type carbide dispersion multi-phase texture crystallizing as primary crystal and eutectic. In the composite material making with ceramic fiber and alloy by the pressure infiltration method, the paper clarified the texture formation mechanism in solidification/heat treatment by a combination of Al alloys and alumina long fiber, and the relation between fiber configuration and wear resistance. By MA and MG methods as the powder metallurgy composite material making method, a composed body of {alpha}-stainless steel of Fe-12%Cr composition and M23C6 of 40-90vol% are designed for alloy composition, and ...

1998-03-01

433

Composites (CFCCs) for low cost energy and cleaner environment. Continuous fiber ceramic composites program

The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers and an increase of approximately 33% for contraction-stimulated transport in slow-twitch red fibers compared with nonexercised sedentary muscle. A fully additive effect of insulin and contractions was observed both in trained and untrained muscle. Compared with transport in control rats subjected to an almost exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training session. Half-times for reversal of contraction-induced ...

1990-12-01

434

Comparison of Nutrient Content and Cost of Home-Packed Lunches to Reimbursable School Lunch Nutrient Standards and Prices

For many industrial applications, materials are desired which combine light weight, high temperature strength, and stability in corrosive environments. Among competing materials, ceramics are noteworthy candidates for such applications. The use of ceramics is often constrained, however, by brittleness; i.e., low toughness. Ceramic composites are being developed to overcome this limitation. With recent advances in ceramic fiber technology, it is possible to design a composite material based on continuous ceramic fibers embedded in a ceramic matrix. The use of ceramic composites in industrial applications will result in reduced fuel consumption, but will also prevent airborne pollution (principally NO, SO{sub x}, CO{sub 2}, and particulates), and economically benefit the end user through energy and environmental savings and increased competitiveness. Industry will also benefit through increased productivity and consumers will benefit through ...

1994-02-01

435

Cobalt and organics removal effect using fiber filter/reverse osmosis combination process for LLRW from korean PWR NPP

Purpose: The purpose of this study was to compare nutrient content and cost of home-packed lunches to nutrient standards and prices for reimbursable school lunches. Methods: Researchers observed food and beverage contents of 333 home packed lunches at four north Texas elementary schools. Nutritionist Pro was used to analyze lunches for calories, total fat, saturated fat, protein, fiber, vitamin A, vitamin C, calcium, iron, fiber, and sodium content. These values were then compared to National School Lunch Program (NSLP) standards and other nutrient standards. Cost of each home-packed lunch was estimated based on food prices at three local supermarkets. A one-sample t-test (p = 0.05) was used to compare nutrient values of home packed lunches to National School Lunch Program (NSLP) standards. A paired t-test was used to compare cost of home packed lunches to each school's full price for a reimbursable school lunch. Results: Home packed lunches ...

2008-12-01

436

Characterization of detonator performance using photonic Doppler velocimetry

Evaporation system for liquid radioactive waste process has been used in Korean PWR nuclear power plants. The system is the most desirable process for decontamination factor (DF) theoretically. However, during the operation of the system, various problems have been arising such as scaling, carry over, etc. Because these problems make DF low, advanced technologies for liquid radwaste process have been world widely developed instead of keeping evaporation system. The main goal of new technologies is ALARA, ease of operation, cost effectiveness and minimization of environmental effect. Korea Electric Power Corporation is currently developing a combined treatment process for liquid radwaste using Micro-filter, Ultra-filter, Reverse Osmosis (RO) membrane, etc for the purpose of partly enhancement of evaporator and of having an alternative liquid radwaste process system for new reactors. As a part of the above project, the feasibility study using the Rolled Fiber-Filter ...

2001-07-01

437

Stabilization of high-temperature antimony oxide with molybdenum incorporation. Structure of Mo-doped Sb/sub 2/O/sub 4/ by powder neutron diffraction and extended X-ray absorption fine structure spectroscopy

Detonators are used to convert electrical or other energy into an explosive output. This output can then be used to initiate further explosive charges. To aid in the development of explosive systems, it is important to characterize the output of detonators, in particularly the pressure produced. Recent advances over the last five years in high-speed digitizing oscilloscopes and high-bandwidth photodiodes, driven primarily by the telecommunications industry, have enabled the development of a new type of interferometer for measuring high velocities, such as those found in detonics experiments. The Photonic Doppler Velocimeter (PDV) can be visualized as a fiber-based Michelson interferometer. The light from a single-mode fiber laser at 1550 nm is passed through a circulator, which acts to separate bi-directional light. The beam is then reflected via free-space optics off the surface of interest, and then focused back into the same ...

2008-08-01

438

Radiation damage studies on CrO_4"2"- doped alums

It has been discovered that the presence of MoO/sub 3/ lowers the ..cap alpha..-..beta.. transition in Sb/sub 2/O/sub 4/ from 935 to 850/sup 0/C with concurrent dissolution of Mo in the high-temperature (..beta..) form. The structure of Mo-doped ..beta..-Sb/sub 2/O/sub 4/ has been investigated by powder neutron diffraction, extended X-ray absorption fine structure (EXAFS) and Raman spectroscopies, and scanning-electron microscopy (SEM). Cell parameters: a = 12.0571 (12) A, b = 4.8335 (1) A, c = 5.3838 (6) A, ..beta.. = 105.579 (5)/sup 0/, monoclinic, space group C2/c, Z = 4. Combining the results of these techniques leads to the hypothesis that Mo is located interstitially within channels of electron density in the Sb/sub 2/O/sub 4/ structure with concurrent vacancy of two Sb/sup III/ atoms. There is no apparent oxygen deficiency in the resulting structure. 25 references, 6 figures, 3 tables.

1985-10-09

439

Preparation of a high-J sub c YBCO bulk superconductor by the platinum doped melt growth method

Radiation damage studies have been carried out on undoped and CrO_4"2"- doped potassium and ammonium alums. The optical absorption bands observed around 27100 and 36500 cm"-"1 before irradiation have been attributed to the transitions t_1 #-># e and t_1 #-># t_2, on the basis of Ball-hausen and Liehr scheme. On prolonged X-irradiation, these bands disappear in both the alums and three new bands seem to grow in ammonium alum while only two new bands could be seen in potassium alum. EPR studies at RT reveal that there are two lines at g = 2.004 and g = 2.010 in ammonium alum and only one line at g = 2.004 in potassium alum. Besides these two nearly isotropic lines, there is a set of lines around g = 1.95 in both the alums. Correlating the optical and EPR studies it is concluded that SO_3"- and O_3"- centres have formed on X-irradiation in ammonium alum while only SO_3"- seems to have formed in potassium alum. The most important feature is the formation of a new ...

440

Preparation and photocatalytic property of pyrochlore Bi{sub 2}Ti{sub 2}O{sub 7} and (Bi, La) {sub 2}Ti{sub 2}O{sub 7} films

Recently we have found a highly effective additive for the melt growth processings attaining high critical currents in YBCO superconductor. It is platinum and it behaves as an effective grain growth inhibitor for the Y{sub 2}BaCuO{sub 5} phase. Even with less than 1 wt.% doping, Y{sub 2}BaCuO{sub 5} particles becomes less than one micron in size and distribute themselves to become homogeneously embedded in the large grown YBa{sub 2}Cu{sub 3}O{sub y} grains. The sample shows large magnetic hysteresis and a typical J{sub c} value estimated by using Bean's model critical state model is 18000 A/cm{sup 2} at 77 K and 1 T. We found that rhodium has a similar remarkable effect. (orig.).

1991-06-15

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

441

Polysilicon thin film transistors fabricated on low temperature plastic substrates

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

2008-11-28

442

Photoluminescence of europium doped LiInO2 powder

We present device results from polysilicon thin film transistors (TFTs) fabricated at a maximum temperature of 100&hthinsp;{degree}C on polyester substrates. Critical to our success has been the development of a processing cluster tool containing chambers dedicated to laser crystallization, dopant deposition, and gate oxidation. Our TFT fabrication process integrates multiple steps in this tool, and uses the laser to crystallize deposited amorphous silicon as well as create heavily doped TFT source/drain regions. By combining laser crystallization and doping, a plasma enhanced chemical vapor deposition SiO{sub 2} layer for the gate dielectric, and postfabrication annealing at 150&hthinsp;{degree}C, we have succeeded in fabricating TFTs with I{sub ON}/I{sub OFF} ratios {gt}5{times}10{sup 5} and electron mobilities {gt}40 cm{sup 2}/V&hthinsp;s on polyester substrates. {copyright} {ital 1999 American Vacuum Society.}

1999-07-01

443

British Library Electronic Table of Contents (United Kingdom)

Abstract Lithium-indium oxide is one of the candidate materials as solid-state scintillators for solar neutrinos due to an inverse --decay of 115In to 115Sn. On the other hand, when doped with rare-earth ions such as Eu3+ or Sm3+, it becomes a promising phosphor material. In this report we present a simple solid-state procedure for preparation of LiInO2:Eu3+ powders. X-ray diffraction confirmed prod-uct in tetragonal structural form (space group: I41/amd) and no impurity phases were detected. Then, high resolution photoluminescence emission measurements were performed at room and low temperatures to find 5D0 - 7FJ. Emission kinetics from 5D0 level exhibited pure single exponential behavior with lifetime of about 1.5 ms. Maximum energy splitting of 7F1 manifold is recorded as a function of ...

2011-01-01

444

Modeling of the relaxation kinetics of metastable tensile strained Si:C alloys

Lanthanum gallate and ceria composite as electrolyte for solid oxide fuel cells

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

2010-07-01

445

Inverse spinel materials. A new class of high voltage cathode materials for Li-ion batteries

The composite of doped lanthanum gallate (La_0_._9Sr_0_._1Ga_0_._8Mg_0_._2O_2_._8_5, LSGM) and doped ceria (Ce_0_._8Sm_0_._2O_1_._9, CSO) was investigated as an electrolyte for solid oxide fuel cell (SOFC). The LSGM-CSO composite was examined by X-ray diffraction (XRD) and impedance spectroscopy. It was found that the sintered LSGM-CSO composite contains mainly fluorite CeO_2 phase and a minority impurity phase, Sm_3Ga_5O_1_2. The LSGM-CSO composite electrolyte shows a small grain boundary response in the impedance spectroscopy as compared to LSGM and CSO pellets. The composite electrolyte exhibits the highest conductivity in the temperature range of 250-600 "oC, compared to LSGM and CSO. The LSGM-CSO composite can be expected to be an attractive intermediate temperature electrolyte material for solid oxide fuel cells.

2010-03-04

446

Influence of high energy electron irradiation on the characteristics of polysilicon thin film transistors

The influence of Cr on the structure and electrochemical properties of LiCoVO{sub 4} was studied using X-Ray diffraction, scanning electron microscopy, Raman Spectroscopy and cycle tests. Doping levels up to 10 mol% were achieved, which improved the electrochemical stability of the structure of LiCoVO{sub 4}, resulting in a significant increase in the initial charge and discharge capacity. The Raman spectroscopy data for the Cr-doped LiCoVO{sub 4} is similar as for LiCoVO{sub 4}. The replacement of a dopant for the Co-ion in the inverse spinel structure causes several Raman shifts. The X-ray diffraction patterns show no new phases and combined with the Raman spectroscopy data it is concluded that the Cr dopant will be located at the octahedral site (16d) where they create an electronic pathway that enhances the electronic conductivity. However, the capacity dropped significantly after prolonged cycling, which is due to the diffusion of V{sup ...

2003-07-01

447

Influence of high energy electron irradiation on the characteristics of polysilicon thin film transistors

The influence of high energy electron (23 MeV) irradiation on the electrical characteristics of p-channel polysilicon thin film transistors (PSTFTs) was studied. The channel 220 nm thick LPCVD (low pressure chemical vapor deposition) deposited polysilicon layer was phosphorus doped by ion implantation. A 45 nm thick, thermally grown, SiO{sub 2} layer served as gate dielectric. A self-alignment technology for boron doping of the source and drain regions was used. 200 nm thick polysilicon film was deposited as a gate electrode. The obtained p-channel PSTFTs were irradiated with different high energy electron doses. Leakage currents through the gate oxide and transfer characteristics of the transistors were measured. A software model describing the field enhancement and the non-uniform current distribution at textured polysilicon/oxide interface was developed. In order to assess the irradiation-stimulated changes of gate oxide parameters the gate ...

2006-08-15

448

Hydrothermal synthesis of semiconductive PZT solid solutions and electromechancal properties of sintered bodies. Suinetsuho ni yoru handosei PZT koyotai no gosei to shoketsutai no denki kikaiteki seishitsu

The influence of high energy electron (23 MeV) irradiation on the electrical characteristics of p-channel polysilicon thin film transistors (PSTFTs) was studied. The channel 220 nm thick LPCVD (low pressure chemical vapor deposition) deposited polysilicon layer was phosphorus doped by ion implantation. A 45 nm thick, thermally grown, SiO_2 layer served as gate dielectric. A self-alignment technology for boron doping of the source and drain regions was used. 200 nm thick polysilicon film was deposited as a gate electrode. The obtained p-channel PSTFTs were irradiated with different high energy electron doses. Leakage currents through the gate oxide and transfer characteristics of the transistors were measured. A software model describing the field enhancement and the non-uniform current distribution at textured polysilicon/oxide interface was developed. In order to assess the irradiation-stimulated changes of gate oxide parameters the gate oxide ...

2006-08-01

449

High-performance thin-film transistors fabricated using excimer laser processing and grain engineering

Semiconductive crystalline PZT powders doped with Bi and K were synthesized by hydrothermal reaction at 200{degree}C for 48 hours. The synthesis of the crystalline powders became difficult with an increase in doped amount of Bi and K, and in Zr/(Ti+Zr) ratio. Since substantial amounts of Pb remained in solution after hydrothermal reaction, the addition of Pb in excess of 25% was necessary to obtain the stoichiometric composition of the PZT solid solution. Bi contents in the powders were identical to those in starting materials, while K contents were less than expected ones. The electromechanical properties of the sintered bodies could be precisely measured by an admittance-curve-fitting method. The electromechanical coupling factor and piezoelectric coefficient of the sintered bodies varied with the Bi content like those of specimens prepared by solid state reaction, and showed the maximum values at a given Bi content. However, the change in ...

1989-10-01

450

High field ESR of P-doped Si for Quantum Computing Application

High-performance polysilicon thin-film transistors (TFT`s) are fabricated using an excimer laser to recrystallize the undoped channel and dope the source-drain regions. Using a technique the authors call grain engineering they are able to control grain microstructure using laser parameters. Resulting polysilicon films are obtained with average grain sizes of {approximately}4--9 {micro}m in sub-100 nm thick polysilicon films without substrate heating during the laser recrystallization process. Using a simple four-mask self-aligned aluminum top-gate structure, they fabricate TFT`s in these films. By combining the grain-engineered channel polysilicon regions with laser-doped source-drain regions, TFT`s are fabricated with electron mobilities up to 260 cm{sup 2}/Vs and on/off current ratios greater than 10{sup 7} To their knowledge, these devices represent the highest performance laser-processed TFT`s reported to date fabricated without substrate ...

1998-04-01

451

GaAs Blocked-Impurity-Band Detectors for Far-Infrared Astronomy

We measured ESR of phosphorous-doped silicon with a low concentration of P, n, at high magnetic fields and low temperatures to investigate the states of nuclear spin. A sample with n = 6.52 x 10{sup 16} /cm{sup 3} was studied at 2.85 T (80 GHz) from 30 K to 2.3 K by field-modulating cw-ESR for a fixed 0 dB power. As the temperature was lowered, the out-of-phase signal appeared around 18 K, reached at a maximum intensity at 13 K, and disappeared around 6 K. The out-of-phase signal is referred to the field modulation. The in-phase signal started to change from the derivative of absorption spectrum at high temperatures to absorption-like shape around 15 K and asymmetry of intensity for two peaks of hyperfine-separated signals increased as temperatures was lowered. Below 10 K, the saturation of the in-phase signal started to appear. We speculate that the asymmetry is caused by saturation effect and dynamic nuclear polarization of {sup 31}P nuclear spin due to drastic ...

2009-02-01

452

Electron spin resonance investigation of Mn^{2+} ions and their dynamics in manganese doped SrTiO_3

High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 10{sup 13} cm{sup -3}, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing layer of a BIB detector, has been achieved. The control of the donor concentration, however, was found to be insufficient for detector production. The growth by LPE of a high-purity film onto a commercially grown vapor-phase epitaxial (VPE) n-type GaAs doped absorbing layer resulted in a BIB device that showed a significant reduction in the low-temperature dark current compared to the absorbing layer only. Extended optical response was not detected, most ...

2004-12-21

453

Electrogenerated chemiluminescence sensor for metoclopramide determination based on Ru(bpy)32+-doped silica nanoparticles dispersed in Nafion on glassy carbon electrode

Using electron spin resonance, lattice position and dynamic properties of Mn2+ ions were studied in 0.5 and 2 % manganese doped SrTiO3 ceramics prepared by conventional mixed oxide method. The measurements showed that Mn2+ ions substitute preferably up to 97 % for Sr if the ceramics is prepared with a deficit of Sr ions. Motional narrowing of the Mn2+ ESR spectrum was observed when temperature increases from 120 K to 240-250 K that was explained as a manifestation of off-center position of this ion at the Sr site. From the analysis of the ESR spectra the activation energy Ea = 86 mV and frequency factor 1/?0 ? (2-10)x10^(-14) 1/s for jumping of the impurity between symmetrical off-center positions were determined. Both values are in agreement with those derived previously from dielectric relaxation. This proves the origin of dielectric anomalies in SrTiO3:Mn as those produced by the reorientation dynamics of Mn2+ dipoles.

2007-01-01

454

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...

2008-01-01

455

Doping of silicon carbide by ion implantation

Alkaline doped TiO2 sol-gel catalysts: Effect of sintering on catalyst activity and selectivity for acetone condensation

A brief survey is given of some recent results on doping of 4H- and 6H-SiC by ion implantation. The doses and energies used are between 10{sup 9} and 10{sup 15} cm{sup -2} and 100 keV and 5 MeV, respectively, and B and Al ions (p-type dopants) are predominantly studied. After low dose implantation ({<=}10{sup 10} cm{sup -2}) a strong compensation is observed in n-type samples and this holds irrespective of implantation temperature up to 600 C. However, at higher doses (10{sup 14}-10{sup 15} Al/cm{sup 2}) the rate of defect recombination (annihilation) increases substantially during hot implants ({>=}200 C), and in these samples one type of structural defect dominates after post-implant annealing at 1700-2000 C. The defect is identified as a dislocation loop composed of clustered interstitial atoms inserted on the basal plane in the hexagonal crystal structure. Finally, transient enhanced diffusion (TED) of ion-implanted boron in 4H-samples is ...

2001-07-01

456

British Library Electronic Table of Contents (United Kingdom)

In this paper, we prepared by the sol-gel method alkaline titania catalysts, doped by gelling titanium alkoxide with aqueous solutions containing potassium, rubidium or cesium chlorides. XRD patterns showed that samples annealed at 400 and 600degreeC contained a single crystalline phase, anastase. Specific surface areas were higher in samples annealed at 400degreeC (>100m2/g) than in those annealed at 600degreeC (25m2/g). The weight density of basic sites determined by CO2-TPD drastically diminished in samples treated at 600degreeC. Catalysts were tested for the self-condensation of acetone at 300degreeC; main reaction products were isomesityl oxide, mesityl oxide and mesitylene. Samples annealed at 600degreeC showed lower acetone conversion rate and low formation of mesitylene than that o...

2006-01-01

457

Visible semiconductor lasers with the AlGaInP materials system

The rare earth antimonates: spectroscopic properties, crystal field and paramagnetic susceptibility simulations

The AlGaInP materials system has recently supported the development of a variety of visible diode laser devices at wavelengths ranging from yellow to red. Presently, the majority of published results are with materials prepared by organometallic vapor phase epitaxy (OMVPE). Many issues with such materials exist, including impurity doping, the role of crystal ordering, defect formation during epitaxial growth, and the proper quantum well heterostructure design required for best device results. This paper addresses these topics and reviews the present state of the art, and projects the anticipated results when the materials' problems have been solved.

1988-11-02

458

The hunt for ?13 at the Daya Bay nuclear power plant

The rare earth antimonates RE{sub 3}Sb{sub 5}O{sub 12} constitute an isostructural series, where the rare earth site symmetry is S{sub 4}. The spectroscopic properties of pure or doped compounds of this family are studied in order to derive their energy level schemes and to simulate them through the crystal field theory, by using the approximated D{sub 2d} potential. The paramagnetic susceptibilities are calculated with the derived wavefunctions and compared to experiment.

1991-01-01

459

The effect of temperature on the radiative performance of Ho-YAG thin film selective emitters

The Daya Bay reactor neutrino experiment is located at the Daya Bay nuclear power plant in Shenzhen, China. The experiment deploys eight 'identical' antineutrino detectors to measure antineutrino fluxes from six 2.9 GWth reactor cores in three underground experimental halls at different distances. The target zone of the Daya Bay detector is filled with 20 t 0.1% Gd doped LAB liquid scintillator. The baseline uncorrelated detector uncertainty is ?0.38% using current experimental techniques. Daya Bay can reach a sensitivity of sin22?13<0.01 with baseline uncertainties after 3 years of data taking.

2010-03-30

460

Synthesis and scintillation properties of GdCl_3:Ce"3"+ (Gd_1_-_xCe_xCl_3_,x = 0.005-0.08)

The authors present the emitter efficiency results for the thin film 25 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) selective emitter from 1000 to 1700 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns) and used to calculate the radiative efficiency. The radiative efficiency and power density of rare earth doped selective emitters are strongly dependent on temperature and experimental results indicate an optimum temperature (1650 K for Ho YAG) for thermophotovoltaic (TPV) applications.

1995-01-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

461

Simple integral screenprinting process for selective emitter polycrystalline silicon solar cells

Single crystals of GdCl_3 doped with different concentrations of Ce"3"+ have been grown using the Bridgman-Stockbarger technique and their luminescence and scintillation properties were investigated. The luminescence spectrum of GdCl_3:Ce"3"+ is complex and consists of two bands with maxima at 350 nm and 370 nm. The maximal light yield in GdCl_3:Ce"3"+ was observed at #approx#1 mol% of Ce"3"+ (more than 38 000 ph/MeV).

2009-07-08

462

Session 6: Redox Behavior of Cerium-Zirconium-Bismuth Mixed Oxides

This letter describes a new simple fabrication process, developed recently for blue response'' improvement in low-cost polycrystalline silicon solar cells. A selective emitter is created by heavily doping the emitter, followed by a wet etching-back of the cell area between the fingers. An improvement up to 17 mV in {ital V}{sub oc}, 1.5 mA/cm{sup 2} in {ital J}{sub sc}, and 1% (absolute value) in {eta} is obtained. Effective phosphorus gettering, self-alignment, and application in a low-cost full screenprinting technology are the main advantages of the proposed process.

1991-09-23

463

Relations between structural and superconducting properties of bulk and thin film high-T_c materials

The CeO{sub 2}-ZrO{sub 2}-Bi{sub 2}O{sub 3} samples with different bismuth content were prepared in this study. By the doping of Bi{sub 2}O{sub 3} into the lattice, TPR profiles of the CeO{sub 2}-ZrO{sub 2} shifted to lower temperatures and oxygen storage capacity increased remarkably. It is concluded that the reason for such a behavior is probably due to both the formation of oxygen vacancies which enhance the oxygen mobility and the simultaneous reduction of Ce{sup 4+} and Bi{sup 3+} in the mixed oxides. (authors)

2004-07-01

464

Polysilicon TFT fabrication on plastic substrates

The structural ordering of oxygen deficient and Co-doped YBCO (YBa_2Cu_3_-_yCo_yO_6_+_x) have been studied experimentally, and by computer simulations of the oxygen ordering in the basal plane of the structure. The calculations are based on the two-dimensional ASYNNNI model and its modifications. Good agreement is established between the ASYNNNI calculations and the experimentally observed structural properties of the double cell ortho-II structure and the oxygen disordering process from Co-doping into the basal plane. A model that relates the superconducting transition temperature T_c(x) of undoped YBCO and T_c(y) of Co-doped YBCO to the formation of specific domains of the two orthorhombic ordered oxygen phases, ortho-I and ortho-II, shows a close agreement with experimental T_c(x) and T_c(y) data of samples prepared under equilibrium conditions. The structural changes as a result of metal ion substitutions and ...

1984-02-13

465

Plasma immersion ion implantation. (Latest citations from the EI Compendex*plus database). Published Search

Processing techniques utilizing low temperature depositions and pulsed lasers allow the fabrication of polysilicon thin film transistors (TFT`s) on plastic substrates. By limiting the silicon, SiO2, and aluminum deposition temperatures to 100(degrees)C, and by using pulsed laser crystallization and doping of the silicon, we have demonstrated functioning polysilicon TFT`s fabricated on polyester substrates with channel mobilities of up to 7.5 cm2/V-sec and Ion/Ioff current ratios of up to 1x10(to the 6th power).

1997-08-06

466

Phytic acid doped nanoparticles for green anticorrosion coatings

The bibliography contains citations concerning plasma immersion ion implantation (PIII) and equipment. PIII is a new technique to implant plasma ions into materials for surface modification and treatment. Topics include plasma nitriding, semiconductor doping, ion energy distribution, ion dose, pulsed plasma, metal plasma, and defect passivation. References also review applications in semiconductor device and integrated circuit manufacture, silicon material fabrication, aerospace bearings, carbon coatings on metals, and ceramic coatings. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

1998-01-01

467

British Library Electronic Table of Contents (United Kingdom)

In this paper, an environmentally friendly metal corrosion inhibitor, phytic acid, was assembled into the walls of silica nanoparticles via layer-by-layer self-assembly technique (LbL) with poly(allylamine hydrochloride). Such functionalized nanoparticles were uniformly distributed into sol-gel films for metal anticorrosion. The films showed very pronounced and lasting protective efficiency in concentrated salt aqueous solutions as indicated by electrochemical impedance spectroscopy (EIS) measurement. These results may provide a new route for the preparation of environment-friendly anticorrosion coatings.

2010-01-01

468

Photoluminescence of manganese- and copper-doped CdS nanowires

Photoluminescence of manganese- and copper-doped CdS nanowires

Arrays of CdS:Mn{sup 2+}:Cu{sup +} micro- and nanowires grown in polycarbonate ion-track templates exhibit photoluminescence in the spectral domain ranging from 500 to 800 nm at room temperature. A comparison with similar CdS and CdS:Mn{sup 2+} wire arrays is presented. The individual contributions to the emission spectra of Cu{sup +} and Mn{sup 2+} ions in the CdS matrix are explained using their energy level schemes. Also SEM, EDX and EPR data are given for these wires. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

2005-02-01

469

Phase formation in gas-phase combustion and pyrolysis reactions under spark and radio-frequency discharge conditions

Arrays of CdS:Mn"2"+:Cu"+ micro- and nanowires grown in polycarbonate ion-track templates exhibit photoluminescence in the spectral domain ranging from 500 to 800 nm at room temperature. A comparison with similar CdS and CdS:Mn"2"+ wire arrays is presented. The individual contributions to the emission spectra of Cu"+ and Mn"2"+ ions in the CdS matrix are explained using their energy level schemes. Also SEM, EDX and EPR data are given for these wires. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

2005-02-01

470

British Library Electronic Table of Contents (United Kingdom)

Doped ultrafine silicon dioxide powder with a narrow particle size distribution was obtained by RF discharge-stimulated dichlorosilane (SiH2C) oxidation at a low pressure using isobutylene as the combustion inhibitor and chromium hexacarbonyl (Cr(CO)6) as the dopant. The formation and morphology of the ultrafine particles are governed by the parameters of the RF discharge and by the chemical mechanism of the combustion reaction yielding the aerosol. Submicron-sized filamentous carbon structures can be obtained by isobutylene decomposition under spark discharge conditions in the presence of a molybdenum metal catalyst.

2009-01-01

471

Nuclear borehole logging using lithium detector assemblies

Mechanisms of Alloy 800 corrosion in helium

A method and apparatus for nuclear borehole logging, and in particular, neutron porosity logging, uses a neutron source, and a pair of spaced lithium detectors, preferably Li"6I crystal or Li"6 doped glass, to detect neutrons emitted from a borehole formation being logged. The spectrum developed by the lithium detectors is processed to remove the gamma ray background radiation and the hydrogen absorption peak, thus allowing a more accurate neutron count. A Gaussian curve is fitted to the neutron peak of the spectrum, the curve eliminating the hydrogen absorption peak. The area under this Gaussian curve represents the neutron count. (author).

1991-11-01

472

Magnetic structure of Ce(Ru_0_._9_6Pd_0_._0_4)_2Si_2

Cr_2O_3 scales are found to form on Alloy 800 and a similar pure ternary alloy in air, and 1 and 50 atm. helium containing oxidizing impurities typical of those in an SGHTR. The strong temperature dependence and neglibible helium overpressure dependence indicate that gas transport through the scales is not rate controlling. Surface oxidation rates are therefore controlled by solid state diffusion and the low oxygen partial pressure dependence of the oxidation rate in Alloy 800 is ascribed to the presence of extrinsic defects in the Cr_3O_3 (due to doping by alloying elements) or to the presence of short circuit diffusion paths. (Auth.).

473

Interstitial injection in silicon after high-dose, low-energy arsenic implantation and annealing

The magnetic structure of a tetragonal Ce(Ru_0_._9_6Pd_0_._0_4)_2Si_2 single crystal, determined by neutron diffraction measurements, is similar to that observed in Rh doped alloys. The magnetic moments are oriented and modulated along the c-axis. Here the wave vector is incommensurate: k=(0,0,0.38). At 1.5 K, the moment is estimated to about 0.3 #mu#_B. Magnetization, magnetoresistance and Hall effect measurements performed on this alloy are also reported. (orig.).

474

Infrared spectroscopy analysis of MgO-doped silicon nitride

In this work, we investigate the interstitial injection into the silicon lattice due to high-dose, low-energy arsenic implantation. The approach consists in monitoring the diffusion of the arsenic profile as well as of the boron profile in buried #delta#-doped layers, when amounts of the as-implanted arsenic profile are removed by low-temperature wet silicon etching. The experimental results indicate that the contribution of the implantation damage to the transient enhanced diffusion of boron, and thus the interstitial injection, is not the main one. On the contrary, interstitial generation due to arsenic clustering seems to be more important for the present conditions.

2005-11-14

475

High emittance coverglass

Silicon nitride hybrid ball bearings used in high temperature applications undergo mechanical and environmental degradation. To study the surface chemistry of silicon nitride, a CAChe{trademark} Worksystem* has been used to generate the clusters and corresponding transmission vibrational spectra of silicon nitride. In the present study, the effect of surface conditions on the surface chemistry and wear degradation of silicon nitride was evaluated. Infrared reflection spectroscopy (IRRS) used to determine molecular orientations shows a difference in reflectance spectra for fractured and as-received.

1997-12-31

476

Functionalized luminescent oxide nanoparticles for sodium channel imaging at the single molecule level

The authors describe measurements of emittance made on samples of solar cell coverglasses incorporating new coatings both on C-7940 fused silica and on CMX ceria doped microsheet. Samples of a conventional, MgF_2 coating on the same two types of coverglass substrates were included in the measurements as controls. Measurements were made by the calorimetric method of total hemispherical emittance within a cooled chamber as well as by the more common infrared reflectance method. Emittance enhancements from 1 to 4% were measured for the new coatings.

1988-09-26

477

Emittance theory for thin film selective emitter

Lanthanide-ion doped oxide nanoparticles were functionalized for use as fluorescent biological labels. These nanoparticles are synthesized directly in water which facilitates their functionalization, and are very photostable without emission intermittency. Nanoparticles functionalized with guanidinium groups act as artificial toxins and specifically target sodium channels. They are individually detectable in cardiac myocytes, revealing a heterogeneous distribution of sodium channels. Functionalized oxide nanoparticles appear as a novel tool particularly well adapted to long-term single-molecule tracking.

2005-04-01

478

Effect of temperature gradient on thick film selective emitter emittance

Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

1994-08-01

479

Effect of porosity on the superplasticity of an alumina

A temperature gradient across a thick ({ge}.1mm) film selective emitter will produce a significant reduction in the spectral emittance from the no temperature gradient case. Thick film selective emitters of rare earth doped host materials such as yttrium-aluminum-garnet (YAG) are examples where temperature gradient effects are important. In this paper a model is developed for the spectral emittance assuming a linear temperature gradient across the film. Results of the model indicate that temperature gradients will result in reductions the order of 20{percent} or more in the spectral emittance. {copyright} {ital 1997 American Institute of Physics.}

1997-03-01

480

Direct dark matter identification with a hybrid detection technique

To evaluate the effect of porosity on superplasticity behavior, it is essential to use materials of similar initial grain sizes. This can be achieved by HIPing, which provides an effective way of reducing initial porosity while avoiding appreciable grain growth; various levels of porosity can be achieved for similar grain sizes. This note is concerned with the influence of porosity on superplasticity tensile deformation of a fine grained high-purity alumina doped with copper oxide and containing a grain growth inhibitor. Specimens were prepared by slip casting to net-shape and sintering; some presintered specimens were HIPed to reduce porosity. The subsequent superplasticity behavior is related to porosity in the material.

1994-02-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

481

Combining laser chemical processing and aerosol jet printing: a laboratory scale feasibility study

In the quest to understand the ultimate nature of WIMPs, we propose the use of a hybrid detection technique: cylinders filled with liquefied noble gasses, acting as targets, are immersed inside a tank of Gd-doped ultra-pure water that provides an active and efficient veto against neutrons. The evaluation of the background rejection capabilities and physics potential of this instrument have been carried out through a full GEANT4 simulation, assuming the detector will be located at the Canfranc underground laboratory (in the Spanish Pyrenees). Our results compare very favourably with existing or planned experiments in the field. This technique is scalable and will allow to reach target masses of few tonnes in the next future.

2008-01-01

482

British Library Electronic Table of Contents (United Kingdom)

Abstract First results showing the viability of combining laser chemical processing (LCP) and aerosol jet printing (AJP) technologies to produce a high-efficiency front side for silicon solar cells are presented. LCP simultaneously opens the anti-reflection coating (ARC) and highly dopes the underlying silicon to create a selective emitter, while AJP is the first in a two-step fine-line contact formation procedure. The electrical properties as well as the morphology of the resulting structures are presented. Performance similar to that achieved with evaporated TiPdAg metallization is demonstrated. Copyright 2010 John Wiley & Sons, Ltd.

2011-01-01

483

Collective charge excitation of Sr_1_4_-_xCa_xCu_2_4O_4_1. A fingerprint of novel charge ordered state?

Adsorption of ammonia and pyridine on copper(II)-doped magnesium-exchanged smectite clays studied by electron spin resonance

We review recent progress on experimental studies of collective charge excitations in hole-doped spin ladder system Sr_1_4_-_xCa_xCu_2_4O_4_1, focusing on anomalous features of phase excitation. We also discuss possible candidates for related charge ordered state, together with a controversial issue of the hole density transferred from spin chain layers to spin ladder layers. (author)

2007-04-01

484

A new type active personal dosemeter with a solid state detector

The interaction between N-donor adsorbates such as ammonia and pyridine with Cu(II)-exchanged montmorillonite, beidellite, flourohectorite into smectite clays has been studied by electron spin resonance. Cu(II) cations exchanged into smectites coordinate five ammonia or pyridine molecules in beidellite, four ammonia of pyridine molecules in hydroxyhectorite. Thus, the Cu(II) cations bound to the interior surfaces of these smectite clays constitute strong Lewis acid sites. 26 refs., 7 figs., 1 tab.

1993-01-14

485

Synthesis, crystal structures and luminescence properties of the Eu3+-doped yttrium oxotellurates(IV) Y2Te4O11 and Y2Te5O13

We have developed a new type personal dosemeter by using a B-10 doped silicon p-n junction detector with a polyethylene radiator and a polyethylene moderator. The purpose of this study was to develop a real time neutron dosemeter with a nearly flat response in the energy range from thermal to 15 MeV and low angular dependence to the incident neutron direction. The neutron response of the dosemeter was obtained with the Monte Carlo calculation and the monoenergetic neutron experiment in a free air field and also under a condition attached on a phantom.

1988-04-01

486

Self-aligned selective-emitter plasma-etchback and passivation process for screen-printed silicon solar cells

Y2Te4O11:Eu3+ and Y2Te5O13:Eu3+ single crystals in sub-millimeter scale were synthesized from the binary oxides (Y2O3, Eu2O3 and TeO2) using CsCl as fluxing agent. Crystallographic structures of the undoped yttrium oxotellurates(IV) Y2Te4O11 and Y2Te5O13 have been determined and refined from single-crystal X-ray diffraction data. In Y2Te4O11, a layered structure is present where the reticulated sheets consisting of edge-sharing [YO8]13- polyhedra are interconnected by the oxotellurate(IV) units, whereas in Y2Te5O13 only double chains of condensed yttrium-oxygen polyhedra with coordination numbers of 7 and 8 are left, now linked in two crystallographic directions by the oxotellurate(IV) entities. The Eu3+ luminescence spectra and the decay time from different energy levels of the doped compounds were investigated and all detected emission levels were identified. Luminescence properties of the Eu3+ cations have been interpreted in consideration of the now accessible ...

2008-10-01

487

Nonstoichiometry and diffusion in ceria and ceria solid solutions

We studied whether plasma-etching techniques can use standard screen-printed gridlines as etch masks to form self-aligned, patterned-emitter profiles on multicrystalline-silicon (mc-Si) cells from Solarex. We conducted an investigation of plasma deposition and etching processes on full-size mc-Si cells processed in commercial production lines, so that any improvements obtained would be immediately relevant to the PV industry. This investigation determined that reactive ion etching (RIE) is compatible with using standard, commercial, screen-printed gridlines as etch masks to form self-aligned, selectively doped emitter profiles. This process results in reduced gridline contact resistance when followed by plasma-enhanced chemical vapor deposition (PECVD) treatments, an undamaged emitter surface easily passivated by plasma-nitride, and a less heavily doped emitter between gridlines for reduced emitter recombination. This allows for heavier ...

1997-10-14

488

New materials synthesis: characterization of some metal-doped antimony oxides

Some of the results of property measurements of CeO{sub 2} and its solid solutions were reviewed. The deviation from stoichiometry of undoped and doped CeO{sub 2} was presented in several figures, which suggested that CeO{sub 2} fired at high temperatures in air might be nonstoichiometric in some degree. At low temperatures, the deviation from stoichiometry in doped CeO{sub 2} is higher than undoped CeO{sub 2}. As another interesting property, CeO{sub 2} shows high solubility to trivalent cations such as rare earth elements. A possible reason behind this high solubility was presented. The nonstoichiometric defect in undoped CeO{sub 2} and the trivalent cation in solid solution with CeO{sub 2} have to be compensated by other defects. The possible defect structures in this solid solution were reviewed and the most probable structure was chosen based on density measurement and impurity dependence of oxygen diffusion coefficient. Finally the oxygen ...

2003-07-01

489

Luminescence studies of Nd3+- and Yb3+-doped ?-Y(IO3)3 and ?-Y(IO3)3, transparent host matrix in the mid- and beginning of the far-infrared

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

1986-10-01

490

Intrinsic magnetism in Fe doped SnO2 nanoparticles

?-Y(IO3)3 and ?-Y(IO3)3 are transparent until 12.8 and 13.4 ?m, respectively; thus they are interesting as a potential laser matrix in the mid- and beginning of the far-infrared. So, in order to investigate the properties of lanthanides- doped anhydrous yttrium iodate, polycrystalline samples of ?-Y1-xNdx(IO3)3 (0.01?x?0.05), ?-Y1-xNdx(IO3)3 (0.001?x?0.1), ?-Y1-xYbx(IO3)3 (0.01?x?0.33) and ?-Y1-xYbx(IO3)3 (0.01?x?0.25) were synthesized. For Nd3+ ions, fluorescent emissions from the 4F3/2 multiplet were observed at 300 K under pulsed laser excitations at 750 nm and for Yb3+, fluorescent emissions from the 2F5/2 multiplet were observed at 300 K under pulsed laser excitations at 980 nm. The decays of all these emissions were measured. They are exponential and the fluorescence lifetimes are in the range 0.093-0.193 ms for Nd3+ and 0.370-0.541 ms for Yb3+, depending on the nature of the host and the concentration of doping.

2009-03-01

491

Electric-field-dependent electroreflectance spectra of visible-band-gap (InAlGa)P quantum-well structures

Iron doped semiconducting nanoparticles Sn1-xFexO2 with x=0, 0.001, 0.002, 0.003, 0.004, 0.01 and 0.03 were prepared by a sol-gel method. The X-ray diffraction, Transmission Electron Microscopy measurements confirm the rutile structure with no impurity phase. The three characteristic lines of electron spin resonance (ESR) are observed in the doped samples for all compositions, which is a clear evidence for rhombic Fe3+ in rutile phase. The line width of ESR increases with increase in Fe concentration due to induced disorder. The spin-pumping effect is observed at temperatures below 250 K for the samples with x=0.01 and 0.03. However, based on the Curie-Weiss susceptibility, iron is in paramagnetic state and is subject to weak antiferromagnetic interaction. Blue shift in the optical band gap is observed with increase in the Fe content. -- Graphical abstract: The ESR spectra reveal that the nature of Fe in Sn1-xFexO2 samples is isolated rhombic ...

2011-01-01

492

Electric-field-dependent electroreflectance spectra of visible-band-gap (InAlGa)P quantum-well structures

We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 [degree]C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6[degree] towards P(111)[r angle][l angle]111[r angle]A, consist of nominally undoped MQWs surrounded by doped In[sub 0.49]Al[sub 0.51]P cladding layers to form [ital p]-[ital i]-[ital n] diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In[sub 0.49]Ga[sub 0.51]P/In[sub 0.49](Al[sub 0.5]Ga[sub 0.5])[sub 0.51]P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that ...

1994-04-04

493

Effects of helium/DPA ratio, alloy composition and cold work on microstructural evolution and hardening of "5"9Ni-doped Fe-Cr-Ni alloys neutron-irradiated at 465 C

We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 degree C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6 degree towards P(111)right-angle left-angle 111 right-angle A, consist of nominally undoped MQWs surrounded by doped In_0_._4_9Al_0_._5_1P cladding layers to form p-i-n diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In_0_._4_9Ga_0_._5_1P/In_0_._4_9(Al_0_._5Ga_0_._5)_0_._5_1P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that (InAlGa)P materials are promising for ...

494

In-situ measurement of epithelial tissue optical properties: Development and implementation of diffuse reflectance spectroscopy techniques

Three ternary austenitic alloys (Fe-15Cr-25Ni, Fe-15Cr-25Ni-0.04P, Fe-15Cr-45Ni in both annealed and cold worked conditions) were irradiated at 465 C to 0.15, 0.28, and 0.42 dpa at above core position in the Fast Flux Test Facility utilizing the Materials Open Test Assembly to study the separate and synergistic effects of He/dpa ratio, phosphorus addition, nickel content and cold work level on microstructural evolution and hardening. The helium/dpa ratio was varied by isotopic doping with "5"9Ni to enhance the production rate of helium. The helium production rate was evaluated to be 62 appm He/dpa in the "5"9Ni-doped specimens and 0.26 appm He/dpa in the undoped specimens. Transmission electron microscopic examinations revealed that alloy composition affected significantly the evolution of microstructure during irradiation. Phosphorus addition prevented the formation of Frank loops through the precipitation of phosphide. Nickel content ...

1994-06-20

495

Quantification of thin film crystallographic orientation using X-ray diffraction with an area detector

Cancer is a severe threat to human health. Early detection is considered the best way to increase the chance for survival. While the traditional cancer detection method, biopsy, is invasive, noninvasive optical diagnostic techniques are revolutionizing the way that cancer is diagnosed. Reflectance spectroscopy is one of these optical spectroscopy techniques showing promise as a diagnostic tool for pre-cancer detection. When a neoplasia occurs in tissue, morphologic and biochemical changes happen in the tissue, which in turn results in the change of optical properties and reflectance spectroscopy. Therefore, a pre-cancer can be detected by extracting optical properties from reflectance spectroscopy. This dissertation described the construction of a fiberoptic based reflectance system and the development of a series of modeling studies. This research is aimed at establishing an improved understanding of the optical properties of mucosal tissues by analyzing reflectance signals at ...

2009-01-01

496

Preparation of AgCl Nanoparticles@Ancient Textile with Antibacterial Activity under Ultrasound Irradiation

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.

2010-02-19

497

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.

2011-01-01

498

Preliminary study on improvement of cementitious grout thermal conductivity for geothermal heat pump applications