WorldWideScience

Sample records for argon nitrides

  1. Argon gas concentration effects on nanostructured molybdenum nitride layer growth using 100 Hz pulsed dc glow discharge

    Science.gov (United States)

    Ikhlaq, U.; Ahmad, R.; Saleem, S.; Shah, M. S.; Umm-i-Kalsoom; Khan, N.; Khalid, N.

    2012-08-01

    The effect of argon concentration (10%-40%) on the surface properties of molybdenum is studied in nitrogen-argon mixture using 100 Hz pulsed dc glow discharge. The analysis is carried out by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Vickers microhardness tester to investigate surface properties of the nitrided samples. XRD results exhibit the formation of molybdenum nitrides. Crystallite size analysis and SEM morphology confirm the growth of nanostructured molybdenum nitride layers. Moreover, significant increase in surface hardness (by a factor of about two times) is found when the sample is treated for 30% argon in nitrogen-argon mixed plasma.

  2. Surface wet-ability modification of thin PECVD silicon nitride layers by 40 keV argon ion treatments

    Science.gov (United States)

    Caridi, F.; Picciotto, A.; Vanzetti, L.; Iacob, E.; Scolaro, C.

    2015-10-01

    Measurements of wet-ability of liquid drops have been performed on a 30 nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40 keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness.

  3. Effect of hydrogen addition on the deposition of titanium nitride thin films in nitrogen added argon magnetron plasma

    Science.gov (United States)

    Saikia, P.; Bhuyan, H.; Diaz-Droguett, D. E.; Guzman, F.; Mändl, S.; Saikia, B. K.; Favre, M.; Maze, J. R.; Wyndham, E.

    2016-06-01

    The properties and performance of thin films deposited by plasma assisted processes are closely related to their manufacturing techniques and processes. The objective of the current study is to investigate the modification of plasma parameters occurring during hydrogen addition in N2  +  Ar magnetron plasma used for titanium nitride thin film deposition, and to correlate the measured properties of the deposited thin film with the bulk plasma parameters of the magnetron discharge. From the Langmuir probe measurements, it was observed that the addition of hydrogen led to a decrease of electron density from 8.6 to 6.2  ×  (1014 m‑3) and a corresponding increase of electron temperature from 6.30 to 6.74 eV. The optical emission spectroscopy study reveals that with addition of hydrogen, the density of argon ions decreases. The various positive ion species involving hydrogen are found to increase with increase of hydrogen partial pressure in the chamber. The thin films deposited were characterized using standard surface diagnostic tools such as x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), x-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Although it was possible to deposit thin films of titanium nitride with hydrogen addition in nitrogen added argon magnetron plasma, the quality of the thin films deteriorates with higher hydrogen partial pressures.

  4. Surface wet-ability modification of thin PECVD silicon nitride layers by 40 keV argon ion treatments

    International Nuclear Information System (INIS)

    Measurements of wet-ability of liquid drops have been performed on a 30 nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40 keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness. - Highlights: • Measurements of wet-ability of liquid drops on a 30 nm Si3N4 film were performed. • Chemical composition was investigated by X-ray Photoelectron Spectroscopy (XPS). • Surface morphology was tested by Atomic Force Microscopy (AFM). • Ar+ bombardment increases the contact angle, oxygen content and surface roughness

  5. The effect of argon plasma treatment on the permeation barrier properties of silicon nitride layers

    OpenAIRE

    Majee, Subimal; Cerqueira, M. F.; Tondelier, D.; Geffroy, B.; Bonnassieux, Y.; Alpuim, P.; Bourée, J. E.

    2013-01-01

    In this work we produce and study silicon nitride (SiNx) thin films deposited by Hot Wire Chemical Vapor Depo- sition (HW-CVD) to be used as encapsulation barriers for flexible organic photovoltaic cells fabricated on poly- ethylene terephthalate (PET) substrates in order to increase their shelf lifetime. We report on the results of SiNx double-layers and on the equivalent double-layer stack where an Ar-plasma surface treatment was performed on the first SiNx layer. The Ar-plasma treatment ma...

  6. Synthesis of SiC Whiskers from Silicon Nitride in Argon Atmosphere

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying; JIANG Mingxue; ZHANG Junzhan; CUI Xiwen

    2009-01-01

    SiC whiskers were synthesized by carbothermal reduction of silicon nitride,a-Si3N4 and β-Si3N4 powders were used as silicon sources,and graphite,active carbon and black carbon as carbon sources,as well as boron oxide as catalyst. The synthesized SiC whiskers were characterized by XRD and SEM.The results showed that the synthesizing temperature should be above 1 716 K;the decomposition of Si3N4 was the limited step in the synthesis of SiC whiskers; and catalyst not only offered the liquid condition,but also restricted the growth of SiC whiskers along one dimension.LS mechanism seems to explain well the growth of SiC whiskers.

  7. Spontaneously-acoustic hypersound long-range stimulation of silicon nitride synthesis in silicon at argon ion irradiation

    CERN Document Server

    Demidov, E S; Markov, K A; Sdobnyakov, V V

    2001-01-01

    The work is dedicated to the nature of the average energy ions implantation process effect on the crystal defective system at the distances, exceeding by three-four orders the averagely projected ions run value. It is established that irradiation by the argon ions stimulated the Si sub 3 N sub 4 phase formation in the preliminarily nitrogen-saturated layers at the distances of approximately 600 mu m from the ions deceleration zone. It is supposed that there appear sufficiently effective pulse sources of the hypersonic shock waves in the area of the Ar sup + deceleration zone. These waves are the result of the jump-like origination and grid evolution of the loop-shaped dislocations and argon blisters as well as of the blisters explosion, The evaluations show that the peak pressure in wave due to the synchronized explosion of blisters in the nitrogen-saturated area on the reverse side of the silicon plate 600 mu m thick may exceed 10 sup 8 Pa and cause experimentally observed changes

  8. Permeation barrier performance of Hot Wire-CVD grown silicon-nitride films treated by argon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Majee, S., E-mail: subimal.majee@polytechnique.edu [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS UMR 7647, Ecole polytechnique, 91128 Palaiseau (France); Cerqueira, M.F. [Centro de Física, Universidade do Minho, 4710-057 Braga (Portugal); Tondelier, D.; Vanel, J.C. [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS UMR 7647, Ecole polytechnique, 91128 Palaiseau (France); Geffroy, B. [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS UMR 7647, Ecole polytechnique, 91128 Palaiseau (France); Laboratoire de Chimie des Surfaces et Interfaces, IRAMIS/SPCSI CEA Saclay, 91191 Gif-sur-Yvette (France); Bonnassieux, Y. [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS UMR 7647, Ecole polytechnique, 91128 Palaiseau (France); Alpuim, P. [Centro de Física, Universidade do Minho, 4710-057 Braga (Portugal); INL–International Iberian Nanotechnology Laboratory, 4715-330 Braga (Portugal); Bourée, J.E., E-mail: jean-eric.bouree@polytechnique.edu [Laboratoire de Physique des Interfaces et des Couches Minces, CNRS UMR 7647, Ecole polytechnique, 91128 Palaiseau (France)

    2015-01-30

    In this work SiN{sub x} thin films have been deposited by Hot-Wire Chemical Vapor Deposition (HW-CVD) technique to be used as encapsulation barriers for flexible organic electronic devices fabricated on polyethylene terephthalate (PET) substrates. First results of SiN{sub x} multilayers stacked and stacks of SiN{sub x} single-layers (50 nm each) separated by an Ar-plasma surface treatment are reported. The encapsulation barrier properties of these different multilayers are assessed using the electrical calcium degradation test by monitoring changes in the electrical conductance of encapsulated Ca sensors with time. The water vapor transmission rate is found to be slightly minimized (7 × 10{sup −3} g/m{sup 2}day) for stacked SiN{sub x} single-layers exposed to argon plasma treatment during a short time (2 min) as compared to that for stacked SiN{sub x} single-layers without Ar plasma treatment. - Highlights: • SiN{sub x} films are grown using HW-CVD to be used as permeation barrier layer. • Ar plasma treatment is made between two successive SiN{sub x} films. • Electrical calcium degradation test is used to evaluate the WVTR values. • Lowest WVTR value of ~ 7 × 10{sup -3} g/m{sup 2}.day is reported.

  9. Permeation barrier performance of Hot Wire-CVD grown silicon-nitride films treated by argon plasma

    International Nuclear Information System (INIS)

    In this work SiNx thin films have been deposited by Hot-Wire Chemical Vapor Deposition (HW-CVD) technique to be used as encapsulation barriers for flexible organic electronic devices fabricated on polyethylene terephthalate (PET) substrates. First results of SiNx multilayers stacked and stacks of SiNx single-layers (50 nm each) separated by an Ar-plasma surface treatment are reported. The encapsulation barrier properties of these different multilayers are assessed using the electrical calcium degradation test by monitoring changes in the electrical conductance of encapsulated Ca sensors with time. The water vapor transmission rate is found to be slightly minimized (7 × 10−3 g/m2day) for stacked SiNx single-layers exposed to argon plasma treatment during a short time (2 min) as compared to that for stacked SiNx single-layers without Ar plasma treatment. - Highlights: • SiNx films are grown using HW-CVD to be used as permeation barrier layer. • Ar plasma treatment is made between two successive SiNx films. • Electrical calcium degradation test is used to evaluate the WVTR values. • Lowest WVTR value of ~ 7 × 10-3 g/m2.day is reported

  10. Radiation Stability of Triple Coatings Based on Transition-Metal Nitrides Under Irradiation By Alpha Particles and Argon Ions

    Science.gov (United States)

    Potekaev, A. I.; Kislitsyn, S. B.; Uglov, V. V.; Klopotov, A. A.; Gorlachev, I. D.; Klopotov, V. D.; Grinkevich, L. S.

    2016-05-01

    The data on the influence of irradiation of (Ti, Cr)N1-x coatings by helium and argon ions on their surface structure are presented. The (Ti, Cr)N1-x coatings 50-300 nm in thickness were formed on carbon steel substrates by vacuum-arc deposition. Irradiation of the coated specimens was performed in a DC-60 heavy-ion accelerator by low-energy 4He+1, 4He+2 and 40Ar5+ ions and high-energy 40Ar5+ ions up to the fluence 1.0·1017 ion/cm2 at the irradiation temperature not higher than 150°C. It is shown that irradiation of the (Ti, Cr)N1-x coating surface by 4He+1, 4He+2 and 40Ar5+ ions with the energy 20 keV/charge does not give rise to any noticeable structural changes nor any surface blistering, while its irradiation by 40Ar5+ ions with the energy 1.50 MeV/amu causes blistering.

  11. Plasma nitriding of AISI 52100 ball bearing steel and effect of heat treatment on nitrided layer

    Indian Academy of Sciences (India)

    Ravindra Kumar; J Alphonsa; Ram Prakash; K S Boob; J Ghanshyam; P A Rayjada; P M Raole; S Mukherjee

    2011-02-01

    In this paper an effort has been made to plasma nitride the ball bearing steel AISI 52100. The difficulty with this specific steel is that its tempering temperature (∼170–200°C) is much lower than the standard processing temperature (∼460–580°C) needed for the plasma nitriding treatment. To understand the mechanism, effect of heat treatment on the nitrided layer steel is investigated. Experiments are performed on three different types of ball bearing races i.e. annealed, quenched and quench-tempered samples. Different gas compositions and process temperatures are maintained while nitriding these samples. In the quenched and quench-tempered samples, the surface hardness has decreased after plasma nitriding process. Plasma nitriding of annealed sample with argon and nitrogen gas mixture gives higher hardness in comparison to the hydrogen–nitrogen gas mixture. It is reported that the later heat treatment of the plasma nitrided annealed sample has shown improvement in the hardness of this steel. X-ray diffraction analysis shows that the dominant phases in the plasma nitrided annealed sample are (Fe2−3N) and (Fe4N), whereas in the plasma nitrided annealed sample with later heat treatment only -Fe peak occurs.

  12. Depleted Argon from Underground Sources

    International Nuclear Information System (INIS)

    Argon is a strong scintillator and an ideal target for Dark Matter detection; however 39Ar contamination in atmospheric argon from cosmic ray interactions limits the size of liquid argon dark matter detectors due to pile-up. Argon from deep underground is depleted in 39Ar due to the cosmic ray shielding of the earth. In Cortez, Colorado, a CO2 well has been discovered to contain approximately 600 ppm of argon as a contamination in the CO2. We first concentrate the argon locally to 3% in an Ar, N2, and He mixture, from the CO2 through chromatographic gas separation, and then the N2 and He will be removed by continuous distillation to purify the argon. We have collected 26 kg of argon from the CO2 facility and a cryogenic distillation column is under construction at Fermilab to further purify the argon.

  13. Argon in action

    CERN Multimedia

    Corinne Pralavorio

    2015-01-01

    Over the past few days, the SPS has been accelerating argon ions, which have started to be sent to the NA61/SHINE experiment. This operating mode, using a new type of ion, required a number of modifications to the accelerator.   Picture 1: a “super-cycle” of the SPS, featuring a proton cycle for the LHC, followed by an argon ion cycle for the North Area. Today, the accelerators are once again juggling particles and even performing completely new tricks. The SPS is supplying beams of argon ions for the first time, at energies never before achieved for this type of beam. They are destined for the NA61/SHINE experiment (see box) located in the North Area, which began receiving the beams on 11 February. Argon ions have a relatively large mass, as they consist of 40 nucleons, so they can be used in a similar way to lead ions. The main difficulty in accelerating them lies in the SPS, where the variation in acceleration frequency is limited. “The SPS was designed for a...

  14. Thermophysical properties of argon

    Energy Technology Data Exchange (ETDEWEB)

    Jaques, A.

    1988-02-01

    The entire report consists of tables of thermodynamic properties (including sound velocity, thermal conductivity and diffusivity, Prandtl number, density) of argon at 86 to 400/degree/K, in the form of isobars over 0.9 to 100 bars. (DLC)

  15. Liquid argon neutrino detectors

    CERN Document Server

    Battistoni, G

    2001-01-01

    The liquid argon imaging technique, as proposed for the ICARUS detector, offers the possibility to perform complementary and simultaneous measurements of neutrinos, as those of CERN to Gran Sasso beam (CNGS) and those from cosmic ray events. For the currently allowed values of the Super-Kamiokande results, the combination of both CNGS and atmospheric data will provide a precise determination of the oscillation parameters. Since one can observe and unambiguously identify nu /sub e/, nu /sub mu / and nu /sub tau / components, this technology allows to explore the full (3*3) mixing matrix. The same class of detector can be proposed for high precision measurements at a neutrino factory. (3 refs).

  16. Isentropic compression of argon

    Energy Technology Data Exchange (ETDEWEB)

    Veeser, L.R.; Ekdahl, C.A.; Oona, H. [and others

    1997-06-01

    The compression was done in an MC-1 flux compression (explosive) generator, in order to study the transition from an insulator to a conductor. Since conductivity signals were observed in all the experiments (except when the probe is removed), both the Teflon and the argon are becoming conductive. The conductivity could not be determined (Teflon insulation properties unknown), but it could be bounded as being {sigma}=1/{rho}{le}8({Omega}cm){sub -1}, because when the Teflon breaks down, the dielectric constant is reduced. The Teflon insulator problem remains, and other ways to better insulate the probe or to measure the conductivity without a probe is being sought.

  17. Diode laser gas nitriding of Ti6Al4V alloy

    OpenAIRE

    A. Lisiecki; A. Klimpel

    2008-01-01

    Purpose: To produce erosion wear resistant and high hardness surface layers of turbofan engine blades and steamturbine blades made of titanium alloy Ti6Al4V laser gas nitrating (LGN) technology of laser alloying was selectedto produce titanium nitrides participations in the titanium alloy matrix surface layers.Design/methodology/approach: Studies on influence of the parameters of laser gas nitriding of titaniumalloy and partial pressure of nitrogen and argon in the gas mixture on the surface ...

  18. Depleted argon from underground sources

    Energy Technology Data Exchange (ETDEWEB)

    Back, H.O.; /Princeton U.; Alton, A.; /Augustana U. Coll.; Calaprice, F.; Galbiati, C.; Goretti, A.; /Princeton U.; Kendziora, C.; /Fermilab; Loer, B.; /Princeton U.; Montanari, D.; /Fermilab; Mosteiro, P.; /Princeton U.; Pordes, S.; /Fermilab

    2011-09-01

    Argon is a powerful scintillator and an excellent medium for detection of ionization. Its high discrimination power against minimum ionization tracks, in favor of selection of nuclear recoils, makes it an attractive medium for direct detection of WIMP dark matter. However, cosmogenic {sup 39}Ar contamination in atmospheric argon limits the size of liquid argon dark matter detectors due to pile-up. The cosmic ray shielding by the earth means that Argon from deep underground is depleted in {sup 39}Ar. In Cortez Colorado a CO{sub 2} well has been discovered to contain approximately 500ppm of argon as a contamination in the CO{sub 2}. In order to produce argon for dark matter detectors we first concentrate the argon locally to 3-5% in an Ar, N{sub 2}, and He mixture, from the CO{sub 2} through chromatographic gas separation. The N{sub 2} and He will be removed by continuous cryogenic distillation in the Cryogenic Distillation Column recently built at Fermilab. In this talk we will discuss the entire extraction and purification process; with emphasis on the recent commissioning and initial performance of the cryogenic distillation column purification.

  19. The Liquid Argon Purity Demonstrator

    CERN Document Server

    Adamowski, M; Dvorak, E; Hahn, A; Jaskierny, W; Johnson, C; Jostlein, H; Kendziora, C; Lockwitz, S; Pahlka, B; Plunkett, R; Pordes, S; Rebel, B; Schmitt, R; Stancari, M; Tope, T; Voirin, E; Yang, T

    2014-01-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  20. The Liquid Argon Purity Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Adamowski, M.; Carls, B.; Dvorak, E.; Hahn, A.; Jaskierny, W.; Johnson, C.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Stancari, M.; Tope, T.; Voirin, E.; Yang, T.

    2014-07-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  1. Fano factor in pure argon

    International Nuclear Information System (INIS)

    The Fano factor for 5.3 MeV alpha particles in pure argon has been measured with a gridded ionization chamber and estimated to be 0.20 (+0.01-0.02). The obtained value is consistent with the theoretical value if the contribution of elastic nuclear collisions to the Fano factor is taken into the consideration. There is no appreciable difference between the values for pure argon and for a gas mixture of Ar (10%)CH4 obtained in the previous measurement. (orig.)

  2. Diffusion of nitrogen in austenitic phase: Application to nitriding of stainless steels

    Directory of Open Access Journals (Sweden)

    Torchane Lazhar

    2014-04-01

    Full Text Available The nitriding treatment of the martensitic stainless steels aims to harden and to introduce compressive stresses on the surface of steel. Hardening is resulting of the martensitic transformation of the austenitic matrix enriched into nitrogen during cooling and of the germination and the nitride growth. In order to preserve the stainless character of the nitrided layer, it is imperative to control precipitation within the zone affected by the treatment. Our task consists in showing that is possible to control the composition of the gas atmosphere containing ammonia and argon and to carry out on the surface of nitrided samples at 1050°C two types of configuration of layers : a single phase layer made up by martensite enriched in nitrogen α’N and or a two phase layer made up by austenite γN and martensite α’N enriched in nitrogen.

  3. Attainable superheat of argon-helium, argon-neon solutions.

    Science.gov (United States)

    Baidakov, Vladimir G; Kaverin, Aleksey M; Andbaeva, Valentina N

    2008-10-16

    The method of lifetime measurement has been used to investigate the kinetics of spontaneous boiling-up of superheated argon-helium and argon-neon solutions. Experiments were made at a pressure of p = 1.5 MPa and concentrations up to 0.33 mol% in the range of nucleation rates from 10 (4) to 10 (8) s (-1) m (-3). The homogeneous nucleation regime has been distinguished. With good agreement between experimental data and homogeneous nucleation theory in temperature and concentration dependences of the nucleation rate, a systematic underestimation by 0.25-0.34 K has been revealed in superheat temperatures over the saturated line attained by experiment as compared with theoretical values calculated in a macroscopic approximation. The revealed disagreement between theory and experiment is connected with the dependence of the properties of new-phase nuclei on their size.

  4. Boron nitride composites

    Science.gov (United States)

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2016-02-16

    According to one embodiment, a composite product includes hexagonal boron nitride (hBN), and a plurality of cubic boron nitride (cBN) particles, wherein the plurality of cBN particles are dispersed in a matrix of the hBN. According to another embodiment, a composite product includes a plurality of cBN particles, and one or more borate-containing binders.

  5. Boron Nitride Nanotubes

    Science.gov (United States)

    Smith, Michael W. (Inventor); Jordan, Kevin (Inventor); Park, Cheol (Inventor)

    2012-01-01

    Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

  6. Binocular indirect argon laser photocoagulator.

    OpenAIRE

    Mizuno, K

    1981-01-01

    The binocular indirect argon laser photocoagulator was newly designed to enable visualisation of the entire fundus during panretinal laser photocoagulation and to treat retinal tears immediately after buckling procedures of the sclera. The lamp housing of the binocular ophthalmoscope was remodelled and adjusted so that the laser beam and illuminating light are coaxial after leaving the ophthalmoscope. The blocking filter was permanently fixed in the eye-pieces to lighten the weight of the oph...

  7. Liquid Argon Barrel Cryostat Arrived

    CERN Multimedia

    Pailler, P

    Last week the first of three cryostats for the ATLAS liquid argon calorimeter arrived at CERN. It had travelled for 46 days over several thousand kilometers from Japan to CERN. During three years it has been fabricated by Kawasaki Heavy Industries Ltd. at Harima, close to Kobe, under contract from Brookhaven National Laboratory (BNL) of the U.S.. This cryostat consists of two concentric cylinders made of aluminium: the outer vacuum vessel with a diameter of 5.5 m and a length of 7 m, and the inner cold vessel which will contain the electromagnetic barrel calorimeter immersed in liquid argon. The total weight will be 270 tons including the detectors and the liquid argon. The cryostat is now located in building 180 where it will be equipped with 64 feed-throughs which serve for the passage of 122,880 electrical lines which will carry the signals of the calorimeter. After integration of the calorimeter, the solenoidal magnet of ATLAS will be integrated in the vacuum vessel. A final cold test of the cryostat inc...

  8. Nitrogen Availability Of Nitriding Atmosphere In Controlled Gas Nitriding Processes

    Directory of Open Access Journals (Sweden)

    Michalski J.

    2015-06-01

    Full Text Available Parameters which characterize the nitriding atmosphere in the gas nitriding process of steel are: the nitriding potential KN, ammonia dissociation rate α and nitrogen availabilitymN2. The article discusses the possibilities of utilization of the nitriding atmosphere’s nitrogen availability in the design of gas nitriding processes of alloyed steels in atmospheres derived from raw ammonia, raw ammonia diluted with pre-dissociated ammonia, with nitrogen, as well as with both nitrogen and pre-dissociated ammonia. The nitriding processes were accomplished in four series. The parameters selected in the particular processes were: process temperature (T, time (t, value of nitriding potential (KN, corresponding to known dissociation rate of the ammonia which dissociates during the nitriding process (α. Variable parameters were: nitrogen availability (mN2, composition of the ingoing atmosphere and flow rate of the ingoing atmosphere (FIn.

  9. Nitrogen incorporation in sputter deposited molybdenum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stöber, Laura, E-mail: laura.stoeber@tuwien.ac.at; Patocka, Florian, E-mail: florian.patocka@tuwien.ac.at; Schneider, Michael, E-mail: michael.schneider@tuwien.ac.at; Schmid, Ulrich, E-mail: ulrich.e366.schmid@tuwien.ac.at [Institute of Sensor and Actuator Systems, TU Wien, Gußhausstraße 27-29, A-1040 Vienna (Austria); Konrath, Jens Peter, E-mail: jenspeter.konrath@infineon.com; Haberl, Verena, E-mail: verena.haberl@infineon.com [Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)

    2016-03-15

    In this paper, the authors report on the high temperature performance of sputter deposited molybdenum (Mo) and molybdenum nitride (Mo{sub 2}N) thin films. Various argon and nitrogen gas compositions are applied for thin film synthetization, and the amount of nitrogen incorporation is determined by Auger measurements. Furthermore, effusion measurements identifying the binding conditions of the nitrogen in the thin film are performed up to 1000 °C. These results are in excellent agreement with film stress and scanning electron microscope analyses, both indicating stable film properties up to annealing temperatures of 500 °C.

  10. Metal Nitrides for Plasmonic Applications

    DEFF Research Database (Denmark)

    Naik, Gururaj V.; Schroeder, Jeremy; Guler, Urcan;

    2012-01-01

    Metal nitrides as alternatives to metals such as gold could offer many advantages when used as plasmonic material. We show that transition metal nitrides can replace metals providing equally good optical performance for many plasmonic applications.......Metal nitrides as alternatives to metals such as gold could offer many advantages when used as plasmonic material. We show that transition metal nitrides can replace metals providing equally good optical performance for many plasmonic applications....

  11. Composing Experimental Environment of PRIDE Argon cell

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Seonho; Jang, Yongkuk; Cho, Il Je [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In PRIDE depleted Uranium feed material and a depleted Uranium mixed with some surrogate material are used for performing engineering scale Pyroprocessing. PRIDE has to maintain inert atmosphere because of the characteristic of Electrolytic Reduction technology, Electro refining technology, Electrowinning technology. The impurity concentration of the Argon cell has to be under 50 ppm(Oxygen, moisture). Atmospheric pressure changes and temperature changes can affect the Argon cell's impurity concentration. In this paper, how to compose the Argon cell impurity concentration under 50 ppm to make the exact optimal experimental environment(Oxygen, moisture) will be introduced. Composing the exact optimal experimental environment by supplying Argon gas have been introduced in this paper. Continuously supplying Argon gas which is heavier than the Oxygen through the bottom of the Argon cell the oxygen eventually discharged through the high vent fan and lower the impurity concentration of Oxygen.

  12. The influence of substrate temperature on the tribo- mechanical properties of chromium nitride thin films

    Science.gov (United States)

    Merie, V. V.; Negrea, G.; Modi, E.

    2016-08-01

    Different nitrides such as titanium nitride, chromium nitride and so on are used in a widespread range of applications such as cutting tools, medical implants, and microelectromechanical devices and all that due to their mechanical, physical and chemical properties. The aim of this study is to obtain chromium nitride thin films and to characterize them by atomic force microscopy investigations. The chromium nitride thin films were deposited by reactive magnetron sputtering on silicon substrates. During the deposition process, the discharge current, the argon and nitrogen flows, the pressure inside the chamber and the deposition time were kept constant. A chromium target with a purity of 99.95 % was used. Some of the films were deposited after a chromium buffer layer was previously deposited on the silicon substrate. The deposition was carried out when substrate temperature was at room temperature, at 300 and 500°C respectively. Once the films were deposited, atomic force microscopy investigations were performed in order to emphasize the influence of the substrate temperature on the topographical, mechanical and tribological characteristics. The results pointed out an important influence of the substrate temperature on topographical, mechanical and tribological properties of the investigated chromium nitride thin films.

  13. Transition probabilities for argon I

    International Nuclear Information System (INIS)

    Transition probabilities for ArI lines have been calculated on the basis of the (j,k)-coupling scheme for more than 16000 spectral lines belonging to the transition arrays 4s-np (n=4 to n=9), 5s-np (n=5 to n=9), 6s-np (n=6 to n=9), 7s-np (n=8 to n=9), 4p-ns (n=5 to n=10), 5p-ns (n=6 to n=9), 6p-ns (n=7 to n=8), 4p-nd (n=3 to n=9), 5p-nd (n=4 to n=9), 3d-np (n=5 to n=9), 4d-np (n=6 to n=9), 5d-np (n=7 to n=9), 3d-nf (n=4 to n=9), 4d-nf (n=4 to n=9), 5d-nf (n=5 to n=9), 4f-nd (n=5 to n=9) 5f-nd (n=6 to n=9), 4f-ng (n=5 to n=9), 5f-ng (n=6 to n=9). Inso far as values by other authors exist, comparison is made with these values. It turns out that the results obtained in (j,k)-coupling are close to those obtained in intermediate coupling except for intercombination lines. For high principal and/or orbital quantum numbers the transition probabilities for a multiplet approach those of the corresponding transitions in atomic hydrogen. The calculated values are applied to construct a simplified argon-atom model, which reflects the real transition properties and which allows simplified but realistic non-equilibrium calculations for argon plasmas which deviate from local thermodynamic equilibrium (LTE)

  14. Opacity of Shock-Generated Argon Plasmas

    Institute of Scientific and Technical Information of China (English)

    王藩侯; 陈敬平; 周显明; 李西军; 经福谦; 孟续军; 孙永盛

    2001-01-01

    Argon plasmas with uniform density and temperature are generated by a planar shock wave through argon gas. The opacities of argon plasma, covering the thermodynamic states at temperatures of 1.4-2.2eV and in densities of 0.0083- 0.015 g/cm3, are investigated by measuring the emitted radiance versus time at several visible wavelengths. Comparison of the measured opacities with those calculated demonstrates that the average atom model can be used well to describe the essential transport behaviour of photons in argon plasma under the abovementioned thermodynamic condition. A simplified and self-consistent method to deduce the reflectivity R(λ) at the baseplate surface is applied. It demonstrates that the values of R(λ) are all around 0.4 in the experiments, which are basically in agreement with those given by Erskine previously (1994 J. Quant. Spectrosc. Radiat.Transfer 51 97).

  15. Status and perspecitves of liquid argon calorimeters

    International Nuclear Information System (INIS)

    The status of liquid argon calorimeters is reviewed, and experience obtained with these devices is described. Future perspectives of the liquid ionization chamber technique in calorimetry are also discussed. (orig.)

  16. Clinical periodontics with the argon laser

    Science.gov (United States)

    Finkbeiner, R. L.

    1995-04-01

    The argon laser has proven to be a valuable tool for the thermodynamic debridement of the periodontal lesion, incisions and tissue fusion. Illustrations of clinical applications and discussion of laser parameters will be provided.

  17. Argon plasma irradiation of polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Slepicka, P., E-mail: petr.slepicka@vscht.c [Department of Solid State Engineering, Institute of Chemical Technology, 16628 Prague (Czech Republic); Vasina, A. [Department of Solid State Engineering, Institute of Chemical Technology, 16628 Prague (Czech Republic); Kolska, Z. [J.E. Purkyne University, Department of Chemistry, 40096 Usti Nad Labem (Czech Republic); Luxbacher, T. [Anton Paar GmbH, 8054 Graz (Austria); Malinsky, P.; Mackova, A. [Nuclear Physics Institute of Academy of Sciences of the Czech Republic, 25068 Rez (Czech Republic); Svorcik, V. [Department of Solid State Engineering, Institute of Chemical Technology, 16628 Prague (Czech Republic)

    2010-06-15

    Polypropylene samples were exposed to argon plasma discharge and the changes of the PP surface properties were studied by different methods. Surface wettability was derived from contact angle measured by standard goniometry and chemical structure of the plasma modified PP was studied using X-ray photoelectron spectroscopy (XPS) and by Rutherford backscattering spectroscopy (RBS), surface morphology and roughness of samples using AFM. Zeta potential of pristine and modified PP was determined with the SurPASS. The presence of incorporated oxygen in the PP surface layer, about 60 nm thick, was observed in RBS spectra. Oxygen concentration is a decreasing function of the depth. With progressing aging time the oxygen concentration on the PP surface decreases. Plasma treatment results in a rapid decrease of the contact angle, which increases again with increasing aging time. In XPS measurement the oxygen containing structures, created by the plasma treatment, were found on the very surface of the modified PP and the zeta potential being changed too. The significant difference in zeta potential between pristine and plasma treated PP clearly indicates that the plasma treatment leads to a more hydrophilic PP surface.

  18. Negative corona current pulses in argon and in mixture argon with SF6

    International Nuclear Information System (INIS)

    Waveforms of the first negative current pulses in a short negative point-to plane gap in pure argon and argon with SF6 admixture have been investigated with a nanosecond time resolution at a gas pressure 50 kPa as a function of applied gap voltage and content of SF6 in the mixture. We have made an attempt to explain the differences in the discharge development in pure argon and in argon with admixture of SF6 based on the observed changes of the pulse shape. The experimental results obtained will be discussed in context with existing computer simulation models (Authors)

  19. Gallium nitride electronics

    Science.gov (United States)

    Rajan, Siddharth; Jena, Debdeep

    2013-07-01

    In the past two decades, there has been increasing research and industrial activity in the area of gallium nitride (GaN) electronics, stimulated first by the successful demonstration of GaN LEDs. While the promise of wide band gap semiconductors for power electronics was recognized many years before this by one of the contributors to this issue (J Baliga), the success in the area of LEDs acted as a catalyst. It set the field of GaN electronics in motion, and today the technology is improving the performance of several applications including RF cell phone base stations and military radar. GaN could also play a very important role in reducing worldwide energy consumption by enabling high efficiency compact power converters operating at high voltages and lower frequencies. While GaN electronics is a rapidly evolving area with active research worldwide, this special issue provides an opportunity to capture some of the great advances that have been made in the last 15 years. The issue begins with a section on epitaxy and processing, followed by an overview of high-frequency HEMTs, which have been the most commercially successful application of III-nitride electronics to date. This is followed by review and research articles on power-switching transistors, which are currently of great interest to the III-nitride community. A section of this issue is devoted to the reliability of III-nitride devices, an area that is of increasing significance as the research focus has moved from not just high performance but also production-worthiness and long-term usage of these devices. Finally, a group of papers on new and relatively less studied ideas for III-nitride electronics, such as interband tunneling, heterojunction bipolar transistors, and high-temperature electronics is included. These areas point to new areas of research and technological innovation going beyond the state of the art into the future. We hope that the breadth and quality of articles in this issue will make it

  20. Measurements on scintillation light from liquid argon

    International Nuclear Information System (INIS)

    It is shown that an argon calorimeter can operate as a scintillation detector, provided that xenon is added. With the addition of 170 ppm xenon a light yield of 70% has been obtained. In addition the light yield is determined under influence of an electric field, from differently ionising particles and by the use of aluminium mirrors acting as light guides. Finally first measurements with a photomultiplier working at liquid argon temperatures are reported. (orig.)

  1. Argon Laser Photoablation for Postburn Conjunctival Pigmentation

    Directory of Open Access Journals (Sweden)

    Seong Joon Ahn

    2014-01-01

    Full Text Available We report a case of an ocular burn injury from boiling water which resulted in conjunctival pigmentation, 1 week following injury. For cosmetic purposes, 2 sessions of argon laser photoablation were performed. One month after laser treatment, conjunctival pigmentation had been successfully removed and the patient was very satisfied with the results. Argon laser photoablation may be an effective way to remove postburn conjunctival pigmentation.

  2. Initial nitride formation during plasma-nitridation of cobalt surfaces

    Science.gov (United States)

    Mattson, E. C.; Michalak, D. J.; Cabrera, W.; Veyan, J. F.; Chabal, Y. J.

    2016-08-01

    Nitridation of metal surfaces is of central importance in microelectronics and spintronics due to the excellent mechanical, thermal, and electrical properties of refractory nitrides. Here, we examine the chemical and structural modification of cobalt surfaces upon nitrogen plasma treatment, using in situ spectroscopic methods, as a method for synthesis of cobalt nitride thin films. We find that nitrogen is incorporated below the surface and forms an ultrathin film of CoN at temperatures as low as 50 °C. In addition, we observe the incorporation of oxygen and NO+ within the surface region. The nitrided cobalt surfaces are fully passivated by N, O, and NO+. These results provide a route for incorporation of cobalt nitride into a wide range applications.

  3. Argon clusters embedded in helium nanodroplets.

    Science.gov (United States)

    da Silva, Filipe Ferreira; Bartl, Peter; Denifl, Stephan; Echt, Olof; Märk, Tilmann D; Scheier, Paul

    2009-11-14

    Electron impact ionization of argon clusters embedded in helium droplets is investigated. Superior mass resolution makes it possible to distinguish between nominally isobaric cluster ions. An abundance maximum for ArHe(12)(+) is unambiguously confirmed; the spectra also prove the formation of Ar(2)He(n)(+) complexes that had been claimed to fragment into pure Ar(2)(+). Distributions of larger argon cluster ions containing up to 60 atoms closely resemble distributions observed upon electron impact or photoionization of bare argon clusters; caging and evaporative cooling provided by the helium matrix do not suffice to quench fragmentation of the nascent argon cluster ions. Intriguing abundance anomalies are observed in distributions of argon cluster ions that contain water, nitrogen or oxygen impurities. The strong abundance of Ar(55)H(2)O(+), Ar(54)O(2)(+) and Ar(54)N(2)(+) contrasts with the virtual absence of slightly larger cluster ions containing the corresponding impurities. The features are probably related to enhanced cluster ion stability upon closure of the second icosahedral shell but the difference in magic numbers (54 versus 55) and the well-known reactivity of charged argon-nitrogen complexes suggest structural differences. PMID:19851558

  4. The effects of laser surface modification on the microstructure and properties of gas-nitrided 42CrMo4 steel

    Science.gov (United States)

    Kulka, M.; Panfil, D.; Michalski, J.; Wach, P.

    2016-08-01

    Gas nitriding, together with gas carburizing and gas carbonitriding, was the most commonly used thermochemical treatment, resulting in many advantageous properties: high hardness, enhanced corrosion resistance, considerably improved wear resistance and fatigue strength. However, an unfavorable increase in the thickness of compound layer (ε+γ‧) close to the surface was observed after conventional gas nitriding. This was the reason for undesirable embrittlement and flaking. Therefore, a controlled gas nitriding was developed, reducing the thickness of compound layer. In this study, laser modification with or without re-melting was carried out after the controlled gas nitriding in order to change microstructure and to improve wear resistance. The effects of laser beam power on the dimensions of simple laser tracks were analyzed. It enabled to control the obtained microstructure and to select the laser processing parameters during producing the multiple tracks. Such a treatment was necessary to investigate wear resistance. Laser re-melting resulted in dissolving the majority of nitrides as well as in producing the martensitic structure in re-melted and heat-affected zones. This treatment required argon shielding in order to protect the surface against uncontrolled oxidation. Laser heat treatment without re-melting caused a modification of ε nitrides which became less porous and more compact. Simultaneously, it provided heat-affected zone with the partially martensitic structure of increased hardness below compound zone. Argon shielding was not necessary in this case because of the resistance of nitrides to oxidation during rapid heating and cooling. All the laser-modified layers, irrespective if the nitrided layer was re-melted or not, were characterized by the improved wear resistance compared to the typical gas-nitrided layer.

  5. Optical characterization of gallium nitride

    NARCIS (Netherlands)

    Kirilyuk, Victoria

    2002-01-01

    Group III-nitrides have been considered a promising system for semiconductor devices since a few decades, first for blue- and UV-light emitting diodes, later also for high-frequency/high-power applications. Due to the lack of native substrates, heteroepitaxially grown III-nitride layers are usually

  6. Potassium-argon/argon-40-argon-39 geochronology of Cenozoic alkali basalts from the South China Sea

    Institute of Scientific and Technical Information of China (English)

    YAN Quanshu; SHI Xuefa; YANG Yaomin; WANG Kunshan

    2008-01-01

    Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea,the characteristics of volcanic activi-ty of the South China Sea after spreading were studied.The potassium - argon ages of eight alkali basalt samples from the South China Sea,and the argon - argon ages of two samples among them are reported.Apparent ages of the whole rock are 3.80 to 7.91 Ma with an average value of 5.43 Ma (potassium- argon,whole rock),and there is little difference among samples at the same location,e.g.,4.76~5.78 Ma for location S04-12.The argon - argon ages for the two samples are 6.06 and 4.71 Ma,which lie within the age scope of potassium - argon method.The dating results indicate that rock-forming age is from late Miocene to Pli-ocene,which is consistent with erupting event for alkali basalts from adjacent regions of the South China Sea.Volcanic activities occur after the cessation of spreading of the South China Sea,which are controlled by lithospheric fault and the spreading center formed during the spreading period of the South China Sea.These dating results,combined with geochemical characteristics of these basalts,the published chronological data for the South China Sea and its adjacent regions,and the updated geophysical data near Hainan Island,suggest that after the cessation of spreading of the South China Sea,there occur widely distributing magmatic activities which primarily is alkali basalt,and the volcanic activity continues to Quaternary.The activity may be relative to Hainan mantle plume originated from core/mantle boundary.

  7. Argon Collection And Purification For Proliferation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Achey, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hunter, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-09

    In order to determine whether a seismic event was a declared/undeclared underground nuclear weapon test, environmental samples must be taken and analyzed for signatures that are unique to a nuclear explosion. These signatures are either particles or gases. Particle samples are routinely taken and analyzed under the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) verification regime as well as by individual countries. Gas samples are analyzed for signature gases, especially radioactive xenon. Underground nuclear tests also produce radioactive argon, but that signature is not well monitored. A radioactive argon signature, along with other signatures, can more conclusively determine whether an event was a nuclear test. This project has developed capabilities for collecting and purifying argon samples for ultra-low-background proportional counting. SRNL has developed a continuous gas enrichment system that produces an output stream containing 97% argon from whole air using adsorbent separation technology (the flow diagram for the system is shown in the figure). The vacuum swing adsorption (VSA) enrichment system is easily scalable to produce ten liters or more of 97% argon within twelve hours. A gas chromatographic separation using a column of modified hydrogen mordenite molecular sieve has been developed that can further purify the sample to better than 99% purity after separation from the helium carrier gas. The combination of these concentration and purification systems has the capability of being used for a field-deployable system for collecting argon samples suitable for ultra-low-background proportional counting for detecting nuclear detonations under the On-Site Inspection program of the CTBTO verification regime. The technology also has applications for the bulk argon separation from air for industrial purposes such as the semi-conductor industry.

  8. Functionalized boron nitride nanotubes

    Science.gov (United States)

    Sainsbury, Toby; Ikuno, Takashi; Zettl, Alexander K

    2014-04-22

    A plasma treatment has been used to modify the surface of BNNTs. In one example, the surface of the BNNT has been modified using ammonia plasma to include amine functional groups. Amine functionalization allows BNNTs to be soluble in chloroform, which had not been possible previously. Further functionalization of amine-functionalized BNNTs with thiol-terminated organic molecules has also been demonstrated. Gold nanoparticles have been self-assembled at the surface of both amine- and thiol-functionalized boron nitride Nanotubes (BNNTs) in solution. This approach constitutes a basis for the preparation of highly functionalized BNNTs and for their utilization as nanoscale templates for assembly and integration with other nanoscale materials.

  9. Effects of Aqueous Vapour Consistence in Nitriding Furnace on the Quality of the Sintered Nitride

    Institute of Scientific and Technical Information of China (English)

    WANGZijiang

    1998-01-01

    If the aqueous vapour consistence is too high(>0.7%),it is very disadvantageous to the sintered products in the nitriding furnace,when silcon nitride bonded silicon carbide products are synthesized by nitridation of silicon.

  10. Infrared spectra and electronic structure calculations for NN complexes with U, UN, and NUN in solid argon, neon, and nitrogen.

    Science.gov (United States)

    Andrews, Lester; Wang, Xuefeng; Gong, Yu; Kushto, Gary P; Vlaisavljevich, Bess; Gagliardi, Laura

    2014-07-17

    Reactions of laser-ablated U atoms with N2 molecules upon codeposition in excess argon or neon at 4 K gave intense NUN and weak UN absorptions. Annealing produced progressions of new absorptions for the UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes. The neon-to-argon matrix shift decreases with increasing NN ligation and therefore the number of noble gas atoms left in the primary coordination sphere around the NUN molecule. Small matrix shifts are observed when the secondary coordination layers around the primary UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes are changed from neon-to-argon to nitrogen. Electronic structure, energy, and frequency calculations provide support for the identification of these complexes and the characterization of the N≡U≡N and U≡N core molecules as terminal uranium nitrides. Codeposition of U with pure nitrogen produced the saturated U(NN)7 complex, which UV irradiation converted to the NUN(NN)5 complex with slightly lower frequencies than found in solid argon.

  11. Attenuation of vacuum ultraviolet light in liquid argon

    CERN Document Server

    Neumeier, A; Oberauer, L; Potzel, W; Schönert, S; Dandl, T; Heindl, T; Ulrich, A; Wieser, J

    2015-01-01

    The transmission of liquid argon has been measured, wavelength resolved, for a wavelength interval from 118 to 250 nm. The wavelength dependent attenuation length is presented for pure argon. It is shown that no universal wavelength independent attenuation length can be assigned to liquid argon for its own fluorescence light due to the interplay between the wavelength dependent emission and absorption. A decreasing transmission is observed below 130 nm in both chemically cleaned and distilled liquid argon and assigned to absorption by the analogue of the first argon excimer continuum. For not perfectly cleaned argon a strong influence of impurities on the transmission is observed. Two strong absorption bands at 126.5 and 141.0 nm with approximately 2 and 4 nm width, respectively, are assigned to traces of xenon in argon. A broad absorption region below 180 nm is found for unpurified argon and tentatively attributed to the presence of water in the argon sample.

  12. Hard carbon nitride and method for preparing same

    Science.gov (United States)

    Haller, Eugene E.; Cohen, Marvin L.; Hansen, William L.

    1992-01-01

    Novel crystalline .alpha. (silicon nitride-like)-carbon nitride and .beta. (silicon nitride-like)-carbon nitride are formed by sputtering carbon in the presence of a nitrogen atmosphere onto a single crystal germanium or silicon, respectively, substrate.

  13. Structure and Thermal Stability of Copper Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Guangan Zhang

    2013-01-01

    Full Text Available Copper nitride (Cu3N thin films were deposited on glass via DC reactive magnetron sputtering at various N2 flow rates and partial pressures with 150°C substrate temperature. X-ray diffraction and scanning electron microscopy were used to characterize the microstructure and morphology. The results show that the films are composed of Cu3N crystallites with anti-ReO3 structure. The microstructure and morphology of the Cu3N film strongly depend on the N2 flow rate and partial pressure. The cross-sectional micrograph of the film shows typical columnar, compact structure. The thermal stabilities of the films were investigated using vacuum annealing under different temperature. The results show that the introducing of argon in the sputtering process decreases the thermal stability of the films.

  14. Study of the Active Screen Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    Zhao Cheng; C. X. Li; H. Dong; T. Bell

    2004-01-01

    Active screen plasma nitriding (ASPN) is a novel nitriding process, which overcomes many of the practical problems associated with the conventional DC plasma nitriding (DCPN). Experimental results showed that the metallurgical characteristics and hardening effect of 722M24 steel nitrided by ASPN at both floating potential and anodic (zero) potential were similar to those nitrided by DCPN. XRD and high-resolution SEM analysis indicated that iron nitride particles with sizes in sub-micron scale were deposited on the specimen surface in AS plasma nitriding. These indicate that the neutral iron nitride particles, which are sputtered from the active screen and transferred through plasma to specimen surface, are considered to be the dominant nitrogen carder in ASPN. The OES results show that NH could not be a critical species in plasma nitriding.

  15. Scintillation efficiency of liquid argon in low energy neutron-argon scattering

    International Nuclear Information System (INIS)

    Experiments searching for weak interacting massive particles with noble gases such as liquid argon require very low detection thresholds for nuclear recoils. A determination of the scintillation efficiency is crucial to quantify the response of the detector at low energy. We report the results obtained with a small liquid argon cell using a monoenergetic neutron beam produced by a deuterium-deuterium fusion source. The light yield relative to electrons was measured for six argon recoil energies between 11 and 120 keV at zero electric drift field

  16. Scintillation efficiency of liquid argon in low energy neutron-argon scattering

    CERN Document Server

    Creus, W; Amsler, C; Ferella, A D; Rochet, J; Scotto-Lavina, L; Walter, M

    2015-01-01

    Experiments searching for weak interacting massive particles with noble gases such as liquid argon require very low detection thresholds for nuclear recoils. A determination of the scintillation efficiency is crucial to quantify the response of the detector at low energy. We report the results obtained with a small liquid argon cell using a monoenergetic neutron beam produced by a deuterium-deuterium fusion source. The light yield relative to electrons was measured for six argon recoil energies between 11 and 120 keV at zero electric drift field.

  17. Boron nitride converted carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  18. Contraction ionization waves in the argon contracted discharge

    International Nuclear Information System (INIS)

    An investigation of ionization waves in the argon contracted discharge and a definition of their arising propagation mechanism accounting for the specificity of elementary pocesses characteristic of argon are presented. (author)

  19. Thermal decomposition of barium valerate in argon

    DEFF Research Database (Denmark)

    Torres, P.; Norby, Poul; Grivel, Jean-Claude

    2015-01-01

    The thermal decomposition of barium valerate (Ba(C4H9CO2)(2)/Ba-pentanoate) was studied in argon by means of thermogravimetry, differential thermal analysis, IR-spectroscopy, X-ray diffraction and hot-stage optical microscopy. Melting takes place in two different steps, at 200 degrees C and 280...

  20. Antiapoptotic activity of argon and xenon.

    Science.gov (United States)

    Spaggiari, Sabrina; Kepp, Oliver; Rello-Varona, Santiago; Chaba, Kariman; Adjemian, Sandy; Pype, Jan; Galluzzi, Lorenzo; Lemaire, Marc; Kroemer, Guido

    2013-08-15

    Although chemically non-reactive, inert noble gases may influence multiple physiological and pathological processes via hitherto uncharacterized physical effects. Here we report a cell-based detection system for assessing the effects of pre-defined gas mixtures on the induction of apoptotic cell death. In this setting, the conventional atmosphere for cell culture was substituted with gas combinations, including the same amount of oxygen (20%) and carbon dioxide (5%) but 75% helium, neon, argon, krypton, or xenon instead of nitrogen. The replacement of nitrogen with noble gases per se had no effects on the viability of cultured human osteosarcoma cells in vitro. Conversely, argon and xenon (but not helium, neon, and krypton) significantly limited cell loss induced by the broad-spectrum tyrosine kinase inhibitor staurosporine, the DNA-damaging agent mitoxantrone and several mitochondrial toxins. Such cytoprotective effects were coupled to the maintenance of mitochondrial integrity, as demonstrated by means of a mitochondrial transmembrane potential-sensitive dye and by assessing the release of cytochrome c into the cytosol. In line with this notion, argon and xenon inhibited the apoptotic activation of caspase-3, as determined by immunofluorescence microscopy coupled to automated image analysis. The antiapoptotic activity of argon and xenon may explain their clinically relevant cytoprotective effects. PMID:23907115

  1. Keeping argon under a graphene lid-Argon intercalation between graphene and nickel(111)

    Science.gov (United States)

    Späth, Florian; Gotterbarm, Karin; Amende, Max; Bauer, Udo; Gleichweit, Christoph; Höfert, Oliver; Steinrück, Hans-Peter; Papp, Christian

    2016-01-01

    We report on the intercalation of graphene grown on a Ni(111) crystal with argon. Argon is implanted in the Ni(111) crystal by ion bombardment before graphene growth, and diffuses to the surface during the growth of graphene at elevated temperatures. Graphene acts as an atomically thin barrier and keeps the argon underneath. We investigated this system with high resolution X-ray photoelectron spectroscopy. From our experiments we determined the mean quantities of argon under graphene. From our analysis, a simple model to determine the pressure under the graphene layer is presented. In our measurements, we find an increased thermal stability of the intercalated graphene as compared to non-intercalated graphene on Ni(111).

  2. Argon Laser Treatment of Strawberry Hemangioma in Infancy

    OpenAIRE

    Achauer, Bruce M.; Vander Kam, Victoria M.

    1985-01-01

    Argon laser therapy is effective for removing port-wine stains and for reducing cutaneous vascular and pigmented lesions. Strawberry hemangiomas, being much thicker lesions than port-wine stains, were considered not appropriate for argon laser treatment. Using argon laser therapy in 13 cases of strawberry hemangioma, we achieved poor to dramatic results.

  3. Argon laser treatment of strawberry hemangioma in infancy.

    Science.gov (United States)

    Achauer, B M; Vander Kam, V M

    1985-11-01

    Argon laser therapy is effective for removing port-wine stains and for reducing cutaneous vascular and pigmented lesions. Strawberry hemangiomas, being much thicker lesions than port-wine stains, were considered not appropriate for argon laser treatment. Using argon laser therapy in 13 cases of strawberry hemangioma, we achieved poor to dramatic results. PMID:4082569

  4. Synthesis of amorphous carbon nitride by ion implantation

    Institute of Scientific and Technical Information of China (English)

    ChenZ.; OlofinjanaA.; BellJ

    2001-01-01

    N2+ were implanted into diamondlike carbon (DLC) films in an attempt to synthesizeamorphous carbon nitride. The DLC films were previously deposited on steel substrate by using anion beam sputtering deposition (IBSD) where a single Kaufman type ion gun with argon sourcewas used to sputter a graphite target and simultaneously bombard the growing film. Parallel to theion implantation route, amorphous carbon nitride films were also synthesized by directly using thereactive ion beam sputtering deposition (RIBSD) with nitrogen source to incorporate nitrogen intothe film. The structure and properties of the films were determined by using Raman spectroscopy,XPS and nano-indentation. The implantation of N2+ into a-C films offers a higher hardness thanthat directly synthesized by RIBSD, probably through an increase in sp3/sp2 ratio and in the pro-portion of nitrogen atoms chemically bonding to carbon atoms. The results show that althoughthere are differences in film composition, structure and properties between these two processes,both methods can be used for synthesis of nitrogen-containing amorphous DLC thin films whichsignificantly modify the substrate surface.

  5. High-Temperature Thermodynamic Investigation of Nano-Dispersed Nitrides Obtained in Thermal Plasma

    Institute of Scientific and Technical Information of China (English)

    M.GEORGIEVA; G.VISSOKOV; Iv.GRANCHAROV; L.BRAKALOV

    2007-01-01

    The nitrides of transient metals have a high hardness,thermal stability,remarkable wear resistance in aggressive chemical mediums,melted metals and alloys,high corrosion resistance,and low coefficient of electric resistance.Under the conditions of low-temperature argon plasma (LTP),thermodynamic investigations were conducted in the process of obtaining of A1N,TiN and Si3N4 in a temperature range of 1000 K to 6000 K.To investigate the thermodynamic possibility of obtaining nitrides,a computer model was used which provided the equilibrium composition of gaseous and solid phases at different temperatures.The conditions for chemical equilibrium of the system were based on the minimization of Gibbs'energy.

  6. Microstructural investigation of iron nitride layers formed by low-temperature gaseous nitriding

    NARCIS (Netherlands)

    Inia, DK; Vredenberg, AM; Boerma, DO; Tichelaar, FD; Schut, H; van Veen, A

    1999-01-01

    Iron nitride layers were formed by a novel low-temperature gaseous nitriding process. Nitriding occurs at a temperature of 325 degrees C through NH3 decomposition at the surface of Ni (25 nm) coated Fe, followed by N transport through the Ni film into the underlying Fe, where nitride precipitation t

  7. Nanostructured silicon nitride from wheat and rice husks

    Science.gov (United States)

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R.

    2016-04-01

    Nanoparticles, submicron-diameter tubes, and rods of Si3N4 were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si3N4 with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si3N4. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si3N4 combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  8. Utilization of multiwalled boron nitride nanotubes for the reinforcement of lightweight aluminum ribbons.

    Science.gov (United States)

    Yamaguchi, Maho; Pakdel, Amir; Zhi, Chunyi; Bando, Yoshio; Tang, Dai-Ming; Faerstein, Konstantin; Shtansky, Dmitry; Golberg, Dmitri

    2013-01-01

    Multiwalled boron nitride nanotubes (BNNTs) have very attractive mechanical and thermal properties, e.g., elasticity, tensile strength, and high resistance to oxidation, and may be considered as ideal reinforcing agents in lightweight metal matrix composites. Herein, for the first time, Al-BNNT ribbons with various BNNT contents (up to 3 wt.%) were fabricated via melt spinning in an argon atmosphere. BNNTs were randomly dispersed within a microcrystalline Al matrix under ribbon casting and led to more than doubling of room-temperature ultimate tensile strength of the composites compared to pure Al ribbons produced at the similar conditions. PMID:23279813

  9. Plasmonic titanium nitride nanostructures for perfect absorbers

    DEFF Research Database (Denmark)

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel;

    2013-01-01

    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  10. Ion nitridation - physical and technological aspects

    International Nuclear Information System (INIS)

    Ion nitridation, is a technique which allows the formation of a controlled thickness of nitrides in the surface of the material, using this material as the cathode in a low pressure glow discharge, which presents many advantages over the conventional method. A brief review of the ion nitriding technique, the physical fenomena involved, and we discuss technological aspects of this method, are presented. (Author)

  11. Flow Parameters of Argon plasma Discharge

    International Nuclear Information System (INIS)

    Owing to the viscosity, the plasma will be adhering to the inner surface of the outer electrode and outer surface of the inner one. As result that the discharge will be eroding the walls of coaxial system. The thickness of the boundary layer near the walls has been estimated at different positions from the breech of coaxial plasma gun. It is found that the thickness of layer 0.008 cm at the end of inner electrode (17 cm). A coaxial plasma gun device is operated in argon gas at ambient pressure 0.6 Torr and discharge voltage about 10 KV. The electron temperature of argon discharge has been determined by using spectroscopic technique. It is found that kTe=3.4 eV. By knowing the thickness of the boundary layer, the density can be determined. The Reynolds number R=105 and Mach number M=5 i.e. the flow is compressible and hypersonic

  12. Argon laser irradiation of the otolithic organ

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, T.; Nomura, Y.; Young, Y.H.; Hara, M. (Univ. of Tokyo (Japan))

    1990-12-01

    An argon laser was used to irradiate the otolithic organs of guinea pigs and cynomolgus monkeys. After stapedectomy, the argon laser (1.5 W x 0.5 sec/shot) irradiated the utricle or saccule without touching the sensory organs. The stapes was replaced over the oval window after irradiation. The animals used for acute observation were killed immediately for morphologic studies; those used for long-term observation were kept alive for 2, 4, or 10 weeks. Acute observation revealed that sensory and supporting cells were elevated from the basement membrane only in the irradiated area. No rupture of the membranous labyrinth was observed. Long-term observation revealed that the otolith of the macula utriculi had disappeared in 2-week specimens. The entire macula utricili had disappeared in 10-week specimens. No morphologic changes were observed in cochlea, semicircular canals, or membranous labyrinth. The saccule showed similar changes.

  13. Abnormal epidermal changes after argon laser treatment

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, R.A.; Knobler, R.M.; Aberer, E.; Klein, W.; Kocsis, F.; Ott, E. (Univ. of Vienna (Austria))

    1991-02-01

    A 26-year-old woman with a congenital port-wine stain on the forehead was treated three times at 2-month intervals with an argon laser. Six months after the last treatment, moderate blanching and mild scaling confined to the treated area was observed. A biopsy specimen of the treated area revealed a significant decrease in ectatic vessels. However, epidermal changes similar to those of actinic keratosis with disorganized cell layers and marked cytologic abnormalities were seen. Analysis of peripheral blood lymphocytes for a defect in DNA repair was negative. Multiple, argon laser-induced photothermal effects may be responsible for the changes observed in our case and may lead to premalignant epidermal transformation.

  14. Explanation of the memory effect in argon

    Directory of Open Access Journals (Sweden)

    Marković Vidosav

    2005-01-01

    Full Text Available Memory effect - the long time variation of the electrical breakdown time delay on the relaxation time td (τ was observed in argon 24 hours after relaxation times and explained by the long-lived metastable states remaining from the preceding glow. However, the quenching processes reducing the effective lifetime of metastable states several orders of magnitude below that relevant for the time scale of observation were neglected. By applying approximate gas phase models it was found that the early afterglow kinetics up to hundreds of milliseconds is dominated by the decay of molecular argon ions Ar2+ and the approximate value of their ambipolar diffusion coefficient is determined. After that, nitrogen atoms present as impurities and recombined on the cathode surface and/or field emission determine the breakdown time delay down to the cosmic rays and natural radioactivity level.

  15. Mathematical Modelling of Nitride Layer Growth of Low Temperature Gas and Plasma Nitriding of AISI 316L

    Directory of Open Access Journals (Sweden)

    Triwiyanto A.

    2014-07-01

    Full Text Available This paper present mathematical model which developed to predict the nitrided layer thickness (case depth of gas nitrided and plasma nitrided austenitic stainless steel according to Fick’s first law for pure iron by adapting and manipulating the Hosseini’s model to fit the diffusion mechanism where nitrided structure formed by nitrided AISI 316L austenitic stainless steel. The mathematical model later tested against various actual gas nitriding and plasma nitriding experimental results with varying nitriding temperature and nitriding duration to see whether the model managed to successfully predict the nitrided layer thickness. This model predicted the coexistence of ε-Fe2-3N and γ΄-Fe4N under the present nitriding process parameters. After the validation process, it is proven that the mathematical model managed to predict the nitrided layer growth of the gas nitrided and plasma nitrided of AISI 316L SS up to high degree of accuracy.

  16. Anatomy of an Inversion - Argon Isotopes

    Science.gov (United States)

    Zamick, L.; Sharon, Y. Y.; Robinson, S. J. Q.

    2012-02-01

    Two different interactions give similar results for excitation energies and g factors of 2+1 states for most even-even argon isotopes except 46Ar. This is explained in terms of an inversion in J = ½+ and levels in 47K which is successfully obtained by one of the interactions but not the other. This example shows the possible dangers of nuclear astrophysics extrapolations.

  17. Hydrodenitrogenation of pyridine over transition metal nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Milad, I.K.; Smith, K.J. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical Engineering

    1997-11-01

    The use of transition metal nitrides (TMN) as catalysts for hydrodenitrogenation (HDN) was discussed. A study was conducted in which a series of unsupported and supported Mo, Fe, W, Co, Nb, Cr, V and Ti nitrides were examined as catalysts for the HDN of pyridine at atmospheric pressure and 350 degrees C. The catalysts were prepared by temperature programmed nitridation of the metal oxide with NH{sub 3}. It was shown that a single nitride phase was present in each of the catalysts. The Mo nitride showed the greatest activity per gram of catalyst. Co and Fe nitrides showed the highest activities per surface area of the unsupported catalyst. Metal nitrides with lower heats of formation showed higher HDN activity. 1 tab.

  18. Synthesis of ternary nitrides by mechanochemical alloying

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Zhu, J.J.; Lindelov, H.;

    2002-01-01

    Ternary metal nitrides ( of general formula MxM'N-y(z)) attract considerable interest because of their special mechanical, electrical, magnetic, and catalytic properties. Usually they are prepared by ammonolysis of ternary oxides (MxM'O-y(m)) at elevated temperatures. We show that ternary...... transition metal nitrides are also obtained by nitridation of the corresponding ternary carbide at 823 K. This transformation appears to occur by solid-state diffusion of carbide and nitride ions. To establish more general synthesis schemes for ternary nitrides, we have focused on the preparation of ternary...... nitrides by mechanochemical alloying of a binary transition metal nitride (MxN) with an elemental transition metal. In this way, we have been able to prepare Fe3Mo3N and Co3Mo3N by ball-milling of Mo2N with Fe and Co, respectively. The transformation sequence from the starting materials ( the binary...

  19. Development of a low-cost inductively coupled argon plasma

    International Nuclear Information System (INIS)

    The aim of this investigation is to drastically reduce running costs of an inductively coupled plasma. This is done by reducing the argon consumption from 20 l/min to about 1 l/min. First, a sample introduction system operating on 0.1 l/min of carrier argon is described. This system ensures a high ratio of plasma argon and carrier argon even at the low total argon consumptions intended. Next, the developed low consumption plasma is presented. In the proposed design, air is blown perpendicularly against the outside of the torch. A different coil has been developed to make air-cooling efficient. Preliminary data on coupling efficiency for the air-cooled plasma are presented. A similarly low argon consumption has been achieved with water as an external coolant medium. It is concluded that a cheaper alternative to the current ICP has become available. (Auth.)

  20. Effects of Nitrogen contamination in liquid Argon

    Science.gov (United States)

    Acciarri, R.; Antonello, M.; Baibussinov, B.; Baldo-Ceolin, M.; Benetti, P.; Calaprice, F.; Calligarich, E.; Cambiaghi, M.; Canci, N.; Carbonara, F.; Cavanna, F.; Centro, S.; Cocco, A. G.; Di Pompeo, F.; Fiorillo, G.; Galbiati, C.; Gallo, V.; Grandi, L.; Meng, G.; Modena, I.; Montanari, C.; Palamara, O.; Pandola, L.; Piano Mortari, G. B.; Pietropaolo, F.; Raselli, G. L.; Roncadelli, M.; Rossella, M.; Rubbia, C.; Segreto, E.; Szelc, A. M.; Ventura, S.; Vignoli, C.

    2010-06-01

    A dedicated test of the effects of Nitrogen contamination in liquid Argon has been performed at the INFN-Gran Sasso Laboratory (LNGS, Italy) within the WArP R&D program. A detector has been designed and assembled for this specific task and connected to a system for the injection of controlled amounts of gaseous Nitrogen into the liquid Argon. The purpose of the test is to detect the reduction of the Ar scintillation light emission as a function of the amount of the Nitrogen contaminant injected in the Argon volume. A wide concentration range, spanning from ~ 10-1 ppm up to ~ 103 ppm, has been explored. Measurements have been done with electrons in the energy range of minimum ionizing particles (γ-conversion from radioactive sources). Source spectra at different Nitrogen contaminations are analyzed, showing sensitive reduction of the scintillation yield at increasing concentrations. Direct PMT signal acquisition exploiting high time resolution by fast waveform recording allowed high precision extraction of the main characteristics of the scintillation light emission in contaminated LAr. In particular, the decreasing behavior in lifetime and relative amplitude of the slow component is found to be appreciable starting from Script O(1 ppm) of Nitrogen concentrations. The rate constant of the quenching process induced by Nitrogen in liquid Ar has been found to be kQ(N2) = 0.11 ± 0.01 μs-1ppm-1, consistent with a previous measurement of this quantity but with significant improvement in precision. On the other hand, no evidence for absorption by N2 impurities has been found up to the higher concentrations here explored.

  1. Argon diffusion from biotite at high temperature and pressure

    Institute of Scientific and Technical Information of China (English)

    陈道公; 贾命命; 李彬贤; 陆全明; 谢鸿森; 侯渭

    1995-01-01

    t The experiments of argon diffusion dynamics for biotite were carried out at 700 -1000℃ and 0.5 - 2,0 GPa and the diffusion coefficient and activation energy using different models have been calculated. The results indicate that the pressure does affect the argon diffusion and its effect is opposite to that of temperature. When p increases, the activation energy increases and diffusion coefficient decreases. The relation between pressure, closure temperature and cooling rate has been obtained. It is postulated that in low T and high p conditions, the argon diffusion from the environment to the system could occur and incur the appearance of the external argon in minerals.

  2. Near-infrared scintillation of liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, T. [Fermilab; Escobar, C. O. [Campinas State U.; Lippincott, W. H. [Fermilab; Rubinov, P. [Fermilab

    2016-03-03

    Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

  3. Near-infrared scintillation of liquid argon

    CERN Document Server

    Alexander, T; Lippincott, W H; Rubinov, P

    2016-01-01

    Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

  4. Argon isotope fractionation induced by stepwise heating

    Science.gov (United States)

    Trieloff, Mario; Falter, Martina; Buikin, Alexei I.; Korochantseva, Ekaterina V.; Jessberger, Elmar K.; Altherr, Rainer

    2005-03-01

    Noble gas isotopes are widely used to elucidate the history of the rocks in which they have been trapped, either from distinct reservoirs or by accumulation following radioactive decay. To extract noble gases from their host rocks, stepwise heating is the most commonly used technique to deconvolve isotopically different components, e.g., atmospheric, in situ radiogenic, or excess radiogenic from mantle or crustal reservoirs. The accurate determination of the isotopic composition of these different components is of crucial importance, e.g., for ages obtained by 40Ar- 39Ar stepheating plateaus. However, diffusion theory-based model calculations predict that the stepwise thermal extraction process from mineral phases induces isotope fractionation and, hence, adulterates the original composition. Such effects are largely unconsidered, as they are small and a compelling experimental observation is lacking. We report the first unequivocal evidence for significant mass fractionation of argon isotopes during thermal extraction, observed on shungite, a carbon-rich Precambrian sedimentary rock. The degree of fractionation, as monitored by 38Ar/ 36Ar and 40Ar/ 36Ar ratios, very well agrees with theoretical predictions assuming an inverse square root dependence of diffusion coefficient and atomic mass, resulting in easier extraction of lighter isotopes. Hence, subatmospheric 40Ar/ 36Ar ratios obtained for argon extracted at low temperatures may not represent paleoatmospheric argon. Shungite argon resembles modern atmospheric composition, but constraints on the timing of trapping appear difficult to obtain, as shungites are multicomponent systems. In 40Ar- 39Ar stepwise heating, the isotope fractionation effect could cause systematic underestimations of plateau ages, between 0.15 and 0.4% depending on age, or considerably higher if samples contain appreciable atmospheric Ar. The magnitude of this effect is similar to the presently achieved uncertainties of this increasingly

  5. Argon Purification Studies and a Novel Liquid Argon Re-circulation System

    CERN Document Server

    Mavrokoridis, K; Coleman, J; Lightfoot, P K; McCauley, N; McCormick, K J; Touramanis, C

    2011-01-01

    Future giant liquid argon (LAr) time projection chambers (TPCs) require a purity of better than 0.1 parts per billion (ppb) to allow the ionised electrons to drift without significant capture by any electronegative impurities. We present a comprehensive study of the effects of electronegative impurity on gaseous and liquid argon scintillation light, an analysis of the efficacy of various purification chemicals, as well as the Liverpool LAr setup, which utilises a novel re-circulation purification system. Of the impurities tested - Air, O_2, H_2O, N_2 and CO_2 in the range of between 0.01 ppm to 1000 ppm - H_2O was found to have the most profound effect on gaseous argon scintillation light, and N_2 was found to have the least. Additionally, a correlation between the slow component decay time and the total energy deposited with 0.01 ppm - 100 ppm O_2 contamination levels in liquid argon has been established. The superiority of molecular sieves over anhydrous complexes at absorbing Ar gas, N_2 gas and H_2O vapou...

  6. Internal nitride formation during gas-phase thermal nitridation of titanium

    OpenAIRE

    Ajikumar, PK; M. Kamruddin; Shankar, P; Gouda, Ramakrishna; Balamurugan, AK; Nithya, R.; Tyagi, AK; Jayaram, V; Biswas, SK; Raj, Baldev

    2009-01-01

    Titanium nitride surface layers were prepared by gas-phase thermal nitridation of pure titanium in an ammonia atmosphere at 1373 K for different times. In addition to the surface nitride layer, nitride/hydride formation was observed in the bulk of the specimen. The cross-section of the specimen was characterized by various techniques such as optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, secondary ion mass spectrometry and nanomechanical testing, ...

  7. THERMODYNAMIC ANALYSIS AND EXPERIMENTAL VERIFICATION FOR SYNTHESIZING SILICON NITRIDE NANOPARTICLES USING RF PLASMA CVD

    Institute of Scientific and Technical Information of China (English)

    Ruoyu Hong; Jianmin Ding; Hongzhong Li

    2003-01-01

    Silicon nitride nanoparticles were synthesized by radio-frequency (RF) plasma chemical vapor deposition (PCVD) using silicon tetrachloride and ammonia as precursors, and argon as carrier gas. By assuming chemical thermodynamic equilibrium in the system, a computer program based on chemical thermodynamics was used to calculate the compositions of the system at different initial concentrations and final temperatures. At first, five elements and thirty-four species were considered. The effects of temperatures, and concentrations of ammonia, hydrogen and nitrogen on the equilibrium compositions were analyzed. It was found that the optimal reaction temperature range should be 1200 to 1500 K to obtain the highest conversion and yield of Si3N4. The inlet position of ammonia should be lower than that of silicon tetrachloride, and both should be located at the tail of the plasma torch. The best mole ratio of ammonia to silicon tetrachloride was found to be about 6. Later, the influences of water (and oxygen) were considered, and 17 additional species were included in the computations. It was found that oxygen or water content in the raw materials should be as low as possible in order to have high nitride content in the produced Si3N4. Nitrogen or hydrogen might be used to replace some or even all the argon to improve the yield of silicon nitride and reduce the cost. The ratio of ammonia to silicon tetrachloride should be high enough to obtain high conversion, but not excessively high to reduce the oxygen content due to the existence of water in ammonia. The simulated results were verified by experiments.

  8. Ion-beam excitation of liquid argon

    CERN Document Server

    Hofmann, M; Heindl, T; Neumeier, A; Oberauer, L; Potzel, W; Roth, S; Schönert, S; Wieser, J; Ulrich, A

    2015-01-01

    The scintillation light of liquid argon has been recorded wavelength and time resolved with very good statistics in a wavelength interval ranging from 118 nm through 970 nm. Three different ion beams, protons, sulfur ions and gold ions, were used to excite liquid argon. Only minor differences were observed in the wavelength-spectra obtained with the different incident particles. Light emission in the wavelength range of the third excimer continuum was found to be strongly suppressed in the liquid phase. In time-resolved measurements, the time structure of the scintillation light can be directly attributed to wavelength in our studies, as no wavelength shifter has been used. These measurements confirm that the singlet-to-triplet intensity ratio in the second excimer continuum range is a useful parameter for particle discrimination, which can also be employed in wavelength-integrated measurements as long as the sensitivity of the detector system does not rise steeply for wavelengths longer than 190 nm. Using ou...

  9. Argon laser-welded arteriovenous anastomoses.

    Science.gov (United States)

    White, R A; Kopchok, G; Donayre, C; White, G; Lyons, R; Fujitani, R; Klein, S R; Uitto, J

    1987-11-01

    This study compared the healing of laser-welded and sutured canine femoral arteriovenous anastomoses. Arteriovenous fistulas 2 cm in length were created bilaterally in the femoral vessels of 10 dogs and were studied at 1 (n = 2), 2 (n = 2), 4 (n = 3), and 8 (n = 3) weeks. In each animal, one anastomosis (control) was closed with running 6-0 polypropylene sutures, and the contralateral anastomosis (experimental) was sealed with an argon laser (0.5 watt, 4 minutes of exposure, 1830 J/cm2/1 cm length of anastomosis). At removal all experimental anastomoses were patent without hematomas, aneurysms, or luminal narrowing. Histologic examination at 4 weeks revealed that laser-welded anastomoses had less inflammatory response and almost normal collagen and elastin reorientation. At 8 weeks sutured anastomoses had significant intimal hyperplasia whereas laser repairs had normal luminal architecture. Tensile strength and collagen production, measured by the synthesis of hydroxyproline and the steady-state levels of type I and type III procollagen messenger ribonucleic acids, at the anastomoses and in adjacent vein and artery specimens were similar in sutured and laser-welded repairs at 2, 4, and 8 weeks. We conclude that argon laser welding of anastomoses is an acceptable alternative to suture techniques, with the advantage of improved healing without foreign body response and possible diminished intimal hyperplasia at the anastomotic line. PMID:3312648

  10. Electron scattering and transport in liquid argon

    International Nuclear Information System (INIS)

    The transport of excess electrons in liquid argon driven out of equilibrium by an applied electric field is revisited using a multi-term solution of Boltzmann’s equation together with ab initio liquid phase cross-sections calculated using the Dirac-Fock scattering equations. The calculation of liquid phase cross-sections extends previous treatments to consider multipole polarisabilities and a non-local treatment of exchange, while the accuracy of the electron-argon potential is validated through comparison of the calculated gas phase cross-sections with experiment. The results presented highlight the inadequacy of local treatments of exchange that are commonly used in liquid and cluster phase cross-section calculations. The multi-term Boltzmann equation framework accounting for coherent scattering enables the inclusion of the full anisotropy in the differential cross-section arising from the interaction and the structure factor, without an a priori assumption of quasi-isotropy in the velocity distribution function. The model, which contains no free parameters and accounts for both coherent scattering and liquid phase screening effects, was found to reproduce well the experimental drift velocities and characteristic energies

  11. Pollution of liquid argon after neutron irradiation

    CERN Document Server

    Andrieux, M L; Collot, J; de Saintignon, P; Ferrari, A; Hostachy, J Y; Hoummada, A; Martin, P; Merkel, B; Puzo, P; Sauvage, D; Wielers, M

    2001-01-01

    The purpose of the neutron facility installed at SARA is to investigate the behavior of various materials to be used in the ATLAS liquid argon calorimeter, when submitted to fast neutron radiation. The samples are placed in a liquid argon cryostat a few cm away from the neutron source. Various pieces of the electromagnetic calorimeter have been tested in order to evaluate the rate of pollution of the liquid and consequently the possible signal loss in energy measurements. The average fluence was equivalent to the maximum expected in the calorimeter in about 10 years. The most striking feature of the results is that the pollution is not due to oxygen, at least for most of it. Using a particular value of the absorption length derived from these data, a simulation was carried out and the energy signal loss in the calorimeter could be predicted. Within the limits of our present knowledge, the conclusion is that damages due to this pollution will not be a problem. (17 refs).

  12. Pollution of liquid argon after neutron irradiation

    International Nuclear Information System (INIS)

    The purpose of the neutron facility installed at SARA is to investigate the behavior of various materials to be used in the ATLAS liquid argon calorimeter, when submitted to fast neutron radiation. The samples are placed in a liquid argon cryostat a few cm away from the neutron source. Various pieces of the electromagnetic calorimeter have been tested in order to evaluate the rate of pollution of the liquid and consequently the possible signal loss in energy measurements. The average fluence was equivalent to the maximum expected in the calorimeter in about 10 years. The most striking feature of the results is that the pollution is not due to oxygen, at least for most of it. Using a particular value of the absorption length derived from these data, a simulation was carried out and the energy signal loss in the calorimeter could be predicted. Within the limits of our present knowledge, the conclusion is that damages due to this pollution will not be a problem

  13. A Novel kind of Air Cooling Bainite Nitriding Steel and Plasma Nitriding Test

    Institute of Scientific and Technical Information of China (English)

    LI Xin-sheng; LIANG Shu-rong

    2004-01-01

    In order to avoid serious distortion and cracking that may occur with nitrided parts while quenching and tempering, a novel kind of air cooling bainite nitriding steel consisting of Ct, Mo, Mn and Si was developed. After normalized and high temperature tempered, the tested steel has satisfactory strength, toughness and microstructure as well as good nitriding properties.

  14. Silicon nitride-fabrication, forming and properties

    International Nuclear Information System (INIS)

    This article, which is a literature survey of the recent years, includes description of several methods for the formation of silicone nitride, and five methods of forming: Reaction-bonded silicon nitride, sintering, hot pressing, hot isostatic pressing and chemical vapour deposition. Herein are also included data about mechanical and physical properties of silicon nitride and the relationship between the forming method and the properties. (author)

  15. Diode laser gas nitriding of Ti6Al4V alloy

    Directory of Open Access Journals (Sweden)

    A. Lisiecki

    2008-05-01

    Full Text Available Purpose: To produce erosion wear resistant and high hardness surface layers of turbofan engine blades and steamturbine blades made of titanium alloy Ti6Al4V laser gas nitrating (LGN technology of laser alloying was selectedto produce titanium nitrides participations in the titanium alloy matrix surface layers.Design/methodology/approach: Studies on influence of the parameters of laser gas nitriding of titaniumalloy and partial pressure of nitrogen and argon in the gas mixture on the surface layers shape, penetration depth,microhardness, erosion wear resistance at different angles of erodent particles stream were conducted. The highpower diode laser HPDL with a rectangular laser beam of even multimode intensity on the beam spot was appliedin the laser gas nitriding process. Tests of erosion wear resistance were conducted according to the ASTM 76standard at velocity of the erodent particles stream 70 [m/s], at angles 90 [o] and also 30 [o].Findings: High quality surface layers of high hardness and erosion wear resistant were produced on the substrateof titanium alloy Ti6Al4V during Laser Gas Nitriding - LGN. Results of the study show that the erosion resistanceof laser nitrided surface layers is significantly higher compared with the base material of titanium alloy Ti6Al4V,and depends strongly on the inclination angle of the erodent particles stream.Research limitations/implications: Further investigations of internal stresses in the nitrided surface layersand the fatigue strength of extremely hard surface layers are required, because the fatigue strength is decisive forthe functional quality of the surface layers.Practical implications: The investigated technology of laser gas nitriding can be applied for increasing erosionwear resistance of surface layers of turbofan engine blades and steam turbine blades made of titanium alloy.Originality/value: Application of the rectangular diode laser beam spot of multimode and uniform intensity oflaser

  16. Computational and experimental study of copper–gold nitride formation

    Energy Technology Data Exchange (ETDEWEB)

    Ponce-Cázares, I., E-mail: iponce@cnyn.unam.mx [Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Tijuana-Ensenada No. 3918, A. Postal 360, 22860 Ensenada, B.C. (Mexico); Soto, G., E-mail: gerardo@cnyn.unam.mx [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, C.P. 22860 Ensenada, B.C. (Mexico); Moreno-Armenta, Ma. Guadalupe, E-mail: moreno@cnyn.unam.mx [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, C.P. 22860 Ensenada, B.C. (Mexico); De la Cruz, W., E-mail: wencel@cnyn.unam.mx [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, C.P. 22860 Ensenada, B.C. (Mexico)

    2015-08-25

    Highlights: • The new Cu{sub 3}Au-nitride compound was successfully grown by the sputtering method. • This material is Cu{sub 3}Au{sub 0.5}N with cubic system (Pm3m space group), where the gold randomly occupies half of the 1a Wyckoff sites. • The material was a pseudo-gap conductor with conductance as good as a heavily-doped semiconductor at room temperature. - Abstract: This work investigates the formation of a Cu{sub 3}Au-nitride alloy using experimental and computational methods. For this purpose, we prepared a custom-made Cu–Au target and then hit it with argon ions in the presence of molecular nitrogen that produced a film on Corning glass. This film was analyzed using spectroscopic and diffraction techniques. The four-point-probe method and Tauc plots were applied to determine the electrical and optical properties of this thin film. Using first principle calculations a structural model was constructed that validated our observations. The crystalline system that we used was cubic (Pm3m space group) with half the sites filled with Au randomly. The composition was close to Cu{sub 3}Au{sub 0.5}N. In agreement with the electrical measurements and calculations, the Cu{sub 3}Au{sub 0.5}N band structure was highly affected by the Au incorporation since the electrical resistance and carrier density were in the 10{sup −3} Ω cm and 10{sup 22} cm{sup −3} ranges, respectively, and the optical gap decreased 0.61 eV with respect to the Cu{sub 3}N. The material was a pseudo-gap conductor with conductance as good as a heavily-doped semiconductor at room temperature; this should give it great potential for use in the optoelectronics industry.

  17. Property database of TRU nitride fuel

    OpenAIRE

    西 剛史; 荒井 康夫; 高野 公秀; 倉田 正輝

    2014-01-01

    The purpose of this study is to prepare a property database of nitride fuel needed for the fuel design of accelerator-driven system (ADS) for transmutation of minor actinide (MA). Nitride fuel of ADS is characterized by high content of Pu and MA as principal components, and addition of a diluent material such as ZrN. Experimental data or evaluated values from the raw data on properties Pu and MA nitrides, and nitride solid solutions containing ZrN are collected and summarized, which cover the...

  18. WARP: a double phase argon programme for dark matter detection

    International Nuclear Information System (INIS)

    WARP (Wimp ARgon Programme) is a double phase Argon detector for Dark Matter search under construction at Laboratori Nazionali del Gran Sasso. We present recent results obtained operating a prototype with a sensitive mass of 2.3 litres deep underground

  19. Stopping Power of Solid Argon for Helium Ions

    DEFF Research Database (Denmark)

    Besenbacher, F.; Bøttiger, Jørgen; Grauersen, O.;

    1981-01-01

    By means of the Rutherford-backscattering method, the stopping cross section of solid argon has been measured for 0.5–3 MeV helium ions to an accuracy of not, vert, similar3%. The results agree within the experimental accuracies with our earlier measurements for gaseous argon over the energy region...

  20. Nitrogen Removal from Molten Steel under Argon DC Glow Plasma

    Institute of Scientific and Technical Information of China (English)

    SUN Ming-shan; DING Wei-zhong; LU Xiong-gang

    2005-01-01

    Under argon DC glow plasma, the nitrogen removal from molten steel was studied. The experimental result showed that nitrogen mass percent could be reduced to 0.000 8%. The change of polarity had no impact on nitrogen removal when the nitrogen mass percent was low. The mechanism of denitrogenation of molten steel under argon DC glow plasma was discussed.

  1. Comparison of Diode and Argon Laser Lesions in Rabbit Retina

    Institute of Scientific and Technical Information of China (English)

    Hui Zhang; Xiaoxin Li; Bin Li; Jiping Da

    2004-01-01

    Purpose: To compare the histological alteration of retina with various spot intensities between diode and argon lasers in order to instruct the clinical use of 810 nm diode laser.Methods: Transpupillary retinal photocoagulations were performed on 42 eyes of 27pigmented rabbits. Histopathologic alteration of lesions in different intensities and different time intervals after irradiation produced by diode and argon laser was observed and compared using light microscopy. Areas of various lesions measured by image analysis system (CMIAS) were compared quantitatively.Results: Histopathologically, two-week-old grade 2 lesions produced by diode laser induced the disappearance of outer nuclear cells. More than a half of all showed reduction in number of outer nuclear layer cells in argon. Fibroblasts appeared in the diode grade 3lesions 5 days after irradiation. CMIAS data showed that all the areas of diode lesions immediately after photocoagulation were to be larger than those of argon laser lesions in the same spot intensity (P < 0.05). However, twenty-four hours after photocoagulation, the area of the diode lesions increased less than that of the argon laser lesions (8%vs.23%).Conclusion: The acute histological effect caused by 810 nm diode laser and argon green laser is similar,while the expansion of lesion area 24 hours after photocoagulation was less with the diode laser compared to the argon. This may be the first report in the literature regarding quantitative analysis of the delayed reaction of argon green lasers.

  2. Nucleation of iron nitrides during gaseous nitriding of iron; the effect of a preoxidation treatment

    DEFF Research Database (Denmark)

    Friehling, Peter B.; Poulsen, Finn Willy; Somers, Marcel A.J.

    2001-01-01

    grains. On prolonged nitriding, immediate nucleation at the surface of iron grains becomes possible. Calculated incubation times for the nucleation of gamma'-Fe4N1-x during nitriding are generally longer than those observed experimentally in the present work. The incubation time is reduced dramatically......The nucleation of iron nitrides during gaseous nitriding has been investigated using light microscopy and X-ray diffraction. Initially, the nucleation of gamma'-Fe4N1-x on a pure iron surface starts at grain boundaries meeting the surface, from where the nitride grains grow laterally into the iron...

  3. Merging of high speed argon plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Case, A.; Messer, S.; Brockington, S.; Wu, L.; Witherspoon, F. D. [HyperV Technologies Corp., Chantilly, Virginia 22180 (United States); Elton, R. [University of Maryland, College Park, Maryland 20742 (United States)

    2013-01-15

    Formation of an imploding plasma liner for the plasma liner experiment (PLX) requires individual plasma jets to merge into a quasi-spherical shell of plasma converging on the origin. Understanding dynamics of the merging process requires knowledge of the plasma phenomena involved. We present results from the study of the merging of three plasma jets in three dimensional geometry. The experiments were performed using HyperV Technologies Corp. 1 cm Minirailguns with a preionized argon plasma armature. The vacuum chamber partially reproduces the port geometry of the PLX chamber. Diagnostics include fast imaging, spectroscopy, interferometry, fast pressure probes, B-dot probes, and high speed spatially resolved photodiodes, permitting measurements of plasma density, temperature, velocity, stagnation pressure, magnetic field, and density gradients. These experimental results are compared with simulation results from the LSP 3D hybrid PIC code.

  4. Large vessel sealing with the argon laser.

    Science.gov (United States)

    White, R A; Kopchok, G; Donayre, C; Lyons, R; White, G; Klein, S R; Pizzurro, D; Abergel, R P; Dwyer, R M; Uitto, J

    1987-01-01

    This study compared the histology, biochemistry, and tensile strength of laser-welded and sutured canine venotomies, arteriotomies, and arteriovenous fistulas. Twelve animals had bilateral femoral vessels studied, with one repair (control) closed with interrupted 6-0 polypropylene sutures, and the contralateral repair (experimental) welded with the argon laser. Specimens were examined at weekly intervals from 1 to 4 weeks (four animals for each type of repair), and were evaluated histologically by hematoxylin and eosin, elastin, and trichrome stains; biochemically by the formation of [3H]hydroxyproline as an index of collagen synthesis; and mechanically by tensile strength determinations. At removal, all experimental closures were patent without hematomas, aneurysms, or luminal dilatation. Histologic and biochemical examination and tensile strength determinations suggest that laser welding may be an alternative to sutures for repair of large-diameter venotomies, arteriotomies, and arteriovenous fistulas, as healing is comparable to that seen with suture repairs up to 4 weeks postoperatively. PMID:3306233

  5. Vascular Welding Using The Argon Laser

    Science.gov (United States)

    White, Rodney A.; Donayre, Carlos; Kopchok, George; White, Geoffrey; Abergel, R. Patrick; Lyons, Richard; Klein, Stanley; Dwyer, Richard; Uitto, Jouni

    1987-03-01

    This study compared the histology, biochemistry, and tensile strength of laser welded and sutured canine venotomies, arteriotomies and arteriovenous fistulas. Bilateral femoral, carotid or jugular vessels were studied with one repair (control) closed with interrupted 6-0 polypropylene sutures, and the contralatral repair (experimental) welded with the argon laser. Specimens were examined at weekly intervals from 1 to 4 weeks for each type of repair and evaluated histologically by hematoxylineosin, elastin and trichrome stains, biochemically by the formation of [3H] hyaroxyproline as an index of collagen synthesis, ana mechanically by tensile strength determinations. At removal, all experimental closures were patent without hematomas, aneurysms or luminal dilatation. Histologic and biochemical examination and tensile strength determinations suggest that laser welaing may be an alternative to sutures for repair of large diameter venotomies, arteriotomies and arteriovenous fistulas, as they heal comparable to suture repairs up to 4 weeks postoperatively.

  6. Commissioning of the ATLAS liquid argon calorimeters

    CERN Document Server

    Rezaie, Erfan

    ATLAS, a multi-purpose detector built at the LHC at CERN, requires an extensive commissioning campaign to be ready for proton-proton collisions. In this work, we focus on the commissioning of the liquid Argon (LAr) calorimeters, with emphasis on commissioning with cosmic rays. First we outline one phase of the commissioning work, which involves testing of the front-end electronics of the two endcap calorimeters. We then describe two cosmic ray generators as input to a Monte-Carlo simulation of cosmic rays in ATLAS, and compare their results. Finally, we explain a technique developed for this work which uses information from the Tile calorimeters to predict the timing of cosmic rays within the LAr calorimeters, because cosmic rays occur randomly in time whereas the electronics are clocked at [Special characters omitted.] . The results from this analysis tool are compared to default tools, using both simulated and real cosmic ray data in the calorimeters.

  7. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim;

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bulk...

  8. PECVD silicon nitride diaphragms for condenser microphones

    NARCIS (Netherlands)

    Scheeper, P.R.; Voorthuyzen, J.A.; Bergveld, P.

    1991-01-01

    The application of plasma-enhanced chemical vapour deposited (PECVD) silicon nitride as a diaphragm material for condenser microphones has been investigated. By means of adjusting the SiH4/NH3 gas-flow composition, silicon-rich silicon nitride films have been obtained with a relatively low tensile s

  9. Method of preparation of uranium nitride

    Science.gov (United States)

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  10. Atomic Resolution Microscopy of Nitrides in Steel

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson

    2014-01-01

    MN and CrMN type nitride precipitates in 12%Cr steels have been investigated using atomic resolution microscopy. The MN type nitrides were observed to transform into CrMN both by composition and crystallography as Cr diffuses from the matrix into the MN precipitates. Thus a change from one...

  11. Thermodynamics, kinetics and process control of nitriding

    DEFF Research Database (Denmark)

    Mittemeijer, Eric J.; Somers, Marcel A. J.

    1997-01-01

    , the nitriding result is determined largely by kinetics. Nitriding kinetics are shown to be characterised by local near equilibria and stationary states at surfaces and interfaces, and the diffusion coefficient of nitrogen in the various phases, for which new data are presented. The necessary background...

  12. Thermodynamics, kinetics and process control of nitriding

    DEFF Research Database (Denmark)

    Mittemeijer, Eric J.; Somers, Marcel A. J.

    1999-01-01

    , the nitriding result is determined largely by the kinetics of the process. The nitriding kinetics have been shown to be characterised by the occurring local near-equilibria and stationary states at surfaces and interfaces, and the diffusion coefficient of nitrogen in the various phases, for which new data have...

  13. High hardness of alloyed ferrite after nitriding

    International Nuclear Information System (INIS)

    Detailed layer-by layer structure and phase analyses of the diffusion layer of nitrided binary alloys of iron with aluminium, chromium, vanadium and titanium have been carried out by means of a complex technique. Transition d-metals (chromium, vanadium and titanium) raise to a greater degree the solubility of nitrogen in the α solid solution, sharply increases the hardness of ferrite and decrease the depth of the layer. Nitrided binary alloys of iron with chromium, vanadium and titanium are strengthened through precipitation from the nitrogen-saturated α-solid solution of nitrides of alloying elements TiN, VN and CrN of a structure B1. A maximum hardness of ferrite alloyed by chromium, vanadium and titanium is observed after nitriding at 550 deg C when the precipitated special nitrides are fully coherent with the α matrix

  14. Cathodic Cage Plasma Nitriding: An Innovative Technique

    Directory of Open Access Journals (Sweden)

    R. R. M. de Sousa

    2012-01-01

    Full Text Available Cylindrical samples of AISI 1020, AISI 316, and AISI 420 steels, with different heights, were simultaneously treated by a new technique of ionic nitriding, entitled cathodic cage plasma nitriding (CCPN, in order to evaluate the efficiency of this technique to produce nitrided layers with better properties compared with those obtained using conventional ionic nitriding technique. This method is able to eliminate the edge effect in the samples, promoting a better uniformity of temperature, and consequently, a smaller variation of the thickness/height relation can be obtained. The compound layers were characterized by X-ray diffraction, optical microscopy, and microhardness test profile. The results were compared with the properties of samples obtained with the conventional nitriding, for the three steel types. It was verified that samples treated by CCPN process presented, at the same temperature, a better uniformity in the thickness and absence of the edge effect.

  15. Argon laser induced changes to the carbonate content of enamel

    International Nuclear Information System (INIS)

    Argon laser irradiation can be used to cure orthodontic brackets onto teeth in significantly less time than conventional curing lights. In addition, it has been shown that the argon laser seems to impart a demineralization resistance to the enamel. The purpose of this study was to use surface science techniques to ascertain if this demineralization resistance is possibly a result of a decrease in the carbonate content of enamel. Eleven mandibular third molars previously scheduled for extraction were collected and used in the present study. The teeth were sectioned in two and randomly assigned to either the argon laser (457-502 nm; 250 mW cm-2) or the control (no treatment) group. The sections assigned to the argon laser group were cured for 10 s and analyzed. To exaggerate any potential changes the experimental sections were then exposed to a further 110 s of argon laser irradiation. Surface analysis was performed using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results showed no statistically significant change in the carbonate content of enamel after argon laser irradiation (p > 0.05). Thus, it is suggested that any demineralization resistance imparted to the enamel surface by argon laser irradiation is not due to alterations in carbonate content.

  16. Solvothermal synthesis: a new route for preparing nitrides

    CERN Document Server

    Demazeau, G; Denis, A; Largeteau, A

    2002-01-01

    Solvothermal synthesis appears to be an interesting route for preparing nitrides such as gallium nitride and aluminium nitride, using ammonia as solvent. A nitriding additive is used to perform the reaction and, in the case of gallium nitride, is encapsulated by melt gallium. The syntheses are performed in the temperature range 400-800 deg. C and in the pressure range 100-200 MPa. The synthesized powders are characterized by x-ray diffraction and scanning electron microscopy. Finely divided gallium nitride GaN and aluminium nitride AlN, both with wurtzite-type structure, can be obtained by this route.

  17. LArGe - A liquid argon scintillation veto for GERDA

    OpenAIRE

    Heisel, M.(Max-Planck-Institut für Kernphysik, Heidelberg, Germany)

    2011-01-01

    LArGe is a Gerda low-background test facility to study novel background suppression methods in a low-background environment, for possible applications in the Gerda experiment. Gerda searches for the neutrinoless double-beta decay in 76Ge, by operating naked germanium detectors submersed into 65 m3 of liquid argon. Similarly, LArGe runs Ge-detectors in 1 m3 (1.4 tons) of liquid argon, which in addition is instrumented with photomultipliers to detect argon scintillation light. The light is used...

  18. Practical reactor production of {sup 41}Ar from argon clathrate

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, J.R. E-mail: jmercer@pharmacy.ualberta.ca; Duke, M.J.M.; McQuarrie, S.A

    2000-06-01

    The radionuclide {sup 41}Ar has many ideal properties as a gas flow tracer. However, the modest cross-section of {sup 40}Ar for thermal neutron activation makes preparation of suitable activities of {sup 41}Ar technically difficult particularly for low flux reactors. Argon can however be trapped in a molecular complex called a clathrate that can then be irradiated. We prepared argon clathrate and explored its irradiation and stability characteristics. Argon clathrate can be used to provide gigabecquerel quantities of {sup 41}Ar even with low power reactors.

  19. Electron spectroscopy of dilute nitrides

    International Nuclear Information System (INIS)

    The application of electron spectroscopies in dilute nitride semiconductor research for both chemical analysis and the determination of electronic and lattice vibrational properties is described. X-ray photoelectron spectroscopy of the nitrogen bonding configurations in dilute InNxSb1-x and InNxAs1-x alloys is presented. High resolution electron-energy-loss spectroscopy (HREELS) of the plasmon excitations in InNxSb1-x is shown to provide information on the electronic properties of the material, before and after annealing. HREELS is also used to investigate the GaN-like phonon modes in GaNxAs1-x alloys

  20. Graphitic Carbon Nitride Supported Catalysts for Polymer Electrolyte Fuel Cells.

    OpenAIRE

    Mansor, N.; Jorge, A. B.; Corà, F.; Gibbs, C.; Jervis, R.; Mcmillan, P. F.; X. Wang; Brett, D. J.

    2014-01-01

    Graphitic carbon nitrides are investigated for developing highly durable Pt electrocatalyst supports for polymer electrolyte fuel cells (PEFCs). Three different graphitic carbon nitride materials were synthesized with the aim to address the effect of crystallinity, porosity, and composition on the catalyst support properties: polymeric carbon nitride (gCNM), poly(triazine) imide carbon nitride (PTI/Li(+)Cl(-)), and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion...

  1. Kinetic process of nitridation on the α-sapphire surface

    Institute of Scientific and Technical Information of China (English)

    Tang Xingzhou; Li Shuping; Kang Junyong; Chen Jiaqi

    2014-01-01

    We established a model to simulate the growth process of nitridation and clarified the inner mechanisms of nitridation and over-nitridation by combining the kinetic Monte Carlo and molecular dynamics methods.Supported by reflection high-energy electron diffraction results with growth in an MBE system,the tendency of nitridation on α-sapphire in different conditions was observed and analyzed.The best conditions for nitridation on the α-sapphire surface are found by our simulation.

  2. Microstructural Characterization of Low Temperature Gas Nitrided Martensitic Stainless Steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work presents microstructural investigations of the surface zone of low temperature gas nitrided precipitation hardening martensitic stainless steel AISI 630. Grazing incidence X-ray diffraction was applied to investigate the present phases after successive removal of very thin sections...... of the sample surface. The development of epsilon nitride, expanded austenite and expanded martensite resulted from the low temperature nitriding treatments. The microstructural features, hardness and phase composition are discussed with emphasis on the influence of nitriding duration and nitriding potential....

  3. Process for the production of metal nitride sintered bodies and resultant silicon nitride and aluminum nitride sintered bodies

    Science.gov (United States)

    Yajima, S.; Omori, M.; Hayashi, J.; Kayano, H.; Hamano, M.

    1983-01-01

    A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults.

  4. The Effects of Dissolved Methane upon Liquid Argon Scintillation Light

    CERN Document Server

    Jones, B J P; Back, H O; Collin, G; Conrad, J M; Greene, A; Katori, T; Pordes, S; Toups, M

    2013-01-01

    In this paper we report on measurements of the effects of dissolved methane upon argon scintillation light. We monitor the light yield from an alpha source held 20 cm from a cryogenic photomultiplier tube (PMT) assembly as methane is injected into a high-purity liquid argon volume. We observe significant suppression of the scintillation light yield by dissolved methane at the 10 part per billion (ppb) level. By examining the late scintillation light time constant, we determine that this loss is caused by an absorption process and also see some evidence of methane-induced scintillation quenching at higher concentrations (50-100 ppb). Using a second PMT assembly we look for visible re-emission features from the dissolved methane which have been reported in gas-phase argon methane mixtures, and we find no evidence of visible re-emission from liquid-phase argon methane mixtures at concentrations between 10 ppb and 0.1%.

  5. Evidence of electric breakdown induced by bubbles in liquid argon

    CERN Document Server

    Bay, F; Murphy, S; Resnati, F; Rubbia, A; Sergiampietri, F; Wu, S

    2014-01-01

    We report on the results of a high voltage test in liquid argon in order to measure its dielectric rigidity. Under stable conditions and below the boiling point, liquid argon was found to sustain a uniform electric field of 100 kV/cm, applied in a region of 20 cm$^2$ area across 1 cm thick gap. When the liquid is boiling, breakdowns may occur at electric fields as low as 40 kV/cm. This test is one of the R&D efforts towards the Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER) as proposed Liquid Argon Time Projection Chamber (LAr TPC) for the LBNO observatory for neutrino physics, astrophysics and nucleon decay searches.

  6. A purity monitoring system for liquid argon calorimeters

    International Nuclear Information System (INIS)

    For liquid argon calorimeters electronegative impurities dissolved in the medium degrade the detector response and deteriorate the energy resolution, especially at high energies. A concept for a purity monitoring system for liquid argon calorimeters has been developed and is presented here. Special combined monitors of 241Am- and 207Bi-cells are used to monitor the concentration of impurities. The working principle as well as results from test measurements are discussed

  7. Size Determination of Argon Clusters from a Rayleigh Scattering Experiment

    Institute of Scientific and Technical Information of China (English)

    LEI An-Le; ZHAI Hua-Jin; LIU Bing-Chen; LI Zhong; NI Guo-Yuan; XU Zhi-Zhan

    2000-01-01

    Argon clusters are produced in the process of adiabatic expansion of a high backing pressure gas into vacuum through a nozzle. The cluster size is determined by a Rayleigh scattering measurement. The scattered signal measured is proportional to the 2.78th power of gas stagnation pressure. The average cluster sizes vary from 100 to more than 12000 atoms/cluster with the argon gas backing pressures ranging between 3 to 45 atm.

  8. Pulse shape discrimination studies in a liquid Argon scintillation detector

    OpenAIRE

    Pollmann, T.

    2007-01-01

    Liquid rare gases have been gaining popularity as detector media in rare event searches, especially dark matter experiments, and one factor driving their adoption is the possibility to recognise different types of ionizing radiation by the pulse shapes they evoke. This work on pulse shape discrimination in a liquid argon scintillation detector was done in the framework of the GERDA experiment, where liquid argon scintillation signals may be used for background suppression purposes. Liquid arg...

  9. Friction Characteristics of Nitrided Layers on AISI 430 Ferritic Stainless Steel Obtained by Various Nitriding Processes

    Directory of Open Access Journals (Sweden)

    Hakan AYDIN

    2013-03-01

    Full Text Available The influence of plasma, gas and salt-bath nitriding techniques on the friction coefficient of AISI 430 ferritic stainless steel was studied in this paper. Samples were plasma nitrided in 80 % N2 + 20 % H2 atmosphere at 450 °C and 520 °C for 8 h at a pressure of 2 mbar, gas nitrided in NH3 and CO2 atmosphere at 570 °C for 13 h and salt-bath nitrided in a cyanide-cyanate salt-bath at 570 °C for 1.5 h. Characterisation of nitrided layers on the ferritic stainless steel was carried out by means of microstructure, microhardness, surface roughness and friction coefficient measurements. Friction characteristics of the nitrided layers on the 430 steel were investigated using a ball-on-disc friction-wear tester with a WC-Co ball as the counter-body under dry sliding conditions. Analysis of wear tracks was carried out by scanning electron microscopy. Maximum hardness and maximum case depth were achieved on the plasma nitrided sample at 520 ºC for 8 h. The plasma and salt-bath nitriding techniques significantly decreased the average surface roughness of the 430 ferritic stainless steel. The friction test results showed that the salt-bath nitrided layer had better friction-reducing ability than the other nitrided layers under dry sliding conditions. Furthermore, the friction characteristic of the plasma nitrided layer at 520 ºC was better than that of the plasma nitrided layer at 450 °C.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3819

  10. Plasma Nitriding of Low Alloy Sintered Steels

    Institute of Scientific and Technical Information of China (English)

    Shiva Mansoorzadeh; Fakhreddin Ashrafizadeh; Xiao-Ying Li; Tom Bell

    2004-01-01

    Fe-3Cr-0.5Mo-0.3C and Fe-3Cr-1.4Mn-0.5Mo-0.367C sintered alloys were plasma nitrided at different temperatures. Characterization was performed by microhardness measurement, optical microscopy, SEM and XRD. Both materials had similar nitriding case properties. 1.4% manganese did not change the as-sintered microstructure considerably.It was observed that monophase compound layer, γ, formed with increasing temperature. Compound layer thickness increased with increasing temperature while nitriding depth increased up to a level and then decreased. Core softening was more pronounced at higher temperature owing to cementite coarsening.

  11. Power Consideration for Pulsed Discharges in Potassium Seeded Argon

    Institute of Scientific and Technical Information of China (English)

    XIA Sheng-Guo; HE Jun-Jia; LIU Ke-Fu

    2007-01-01

    Minimization of energy consumed in plasma generation is critical for applications, in which a large volume of plasmas is needed. We suggest that a high electron density atmospheric pressure plasmas can be generated by pulsed discharges in potassium seeded argon at an elevated temperature with a very small power input. The ionization efficiency and power budget of pulsed discharges in such plasmas are analytically studied. The results show that ionization efficiency of argon, especially at small reduced electric field E/N (the ratio of the electric field to the gas number density), is improved effectively in the presence of small amount of potassium additives. Power input of pulsed discharge to sustain a prescribed average level of ionization in potassium seeded argon is three orders of magnitude lower than that in pure argon. Further, unlike in pure argon, it is found that very short high-voltage pulses with very high repetition rates are unnecessary in potassium seeded argon. A pulse with 100ns of pulse duration, 5kHz of repetition rate, and 2Td (1 Td = 1 ×10-21 Vm2) of E/N is enough to sustain an electron density of 10l9m-3 in 1 atm 1500 K Ar+0.1% K mixture, with a very small power input of about 0.08 × 104 W/m3.

  12. Energy resolution for α-particles in doped liquid argon

    International Nuclear Information System (INIS)

    The report describes experiments on the effect of allene doped in liquid argon. In the case of doped argon, a large amount of charge is obtained even at low electric fields and the measured charge increases with the field gradually. This can be explained as follows; part of deposited energy which does not form charge in pure argon contributes to charge signal in doped argon through scintillation photons which ionize allene molecules. The main factors determining the energy resolution for α-particles are considered to be (1) fluctuation in the number of produced ion-electron pairs as expressed by the Fano factor, (2) fluctuation in recombination process, (3) fluctuation in photoionization, (4) fluctuation due to the condition of radioactive source and surface of electrodes, (5) fluctuation in geometrical efficiency due to the range and emission angle of α-particles in liquid argon, and (6) electronic noise of amplifier. The factors (1) and (3) can be neglected because of a large number of associated electrons or photons. In pure liquid argon, the factor (2) may be a cause of bad resolution since the fraction of the produced ion-electron paris which do not recombine is small and the photoionization process never occurs for photons emitted through recombination. (N.K.)

  13. Internal nitride formation during gas-phase thermal nitridation of titanium

    International Nuclear Information System (INIS)

    Titanium nitride surface layers were prepared by gas-phase thermal nitridation of pure titanium in an ammonia atmosphere at 1373 K for different times. In addition to the surface nitride layer, nitride/hydride formation was observed in the bulk of the specimen. The cross-section of the specimen was characterized by various techniques such as optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, secondary ion mass spectrometry and nanomechanical testing, and the mechanism of formation of these phases is discussed.

  14. Nitrogen implantation effects on the chemical bonding and hardness of boron and boron nitride coatings

    Energy Technology Data Exchange (ETDEWEB)

    Anders, S; Felter, T; Hayes, J; Jankowski, A F; Patterson, R; Poker, D; Stamler, T

    1999-02-08

    Boron nitride (BN) coatings are deposited by the reactive sputtering of fully dense, boron (B) targets utilizing an argon-nitrogen (Ar-N{sub 2}) reactive gas mixture. Near-edge x-ray absorption fine structure analysis reveals features of chemical bonding in the B 1s photoabsorption spectrum. Hardness is measured at the film surface using nanoindentation. The BN coatings prepared at low, sputter gas pressure with substrate heating are found to have bonding characteristic of a defected hexagonal phase. The coatings are subjected to post-deposition nitrogen (N{sup +} and N{sub 2}{sup +}) implantation at different energies and current densities. The changes in film hardness attributed to the implantation can be correlated to changes observed in the B 1s NEXAFS spectra.

  15. New argon-argon (40Ar/39Ar) radiometric age dates from selected subsurface basalt flows at the Idaho National Laboratory, Idaho

    Science.gov (United States)

    Hodges, Mary K.; Turrin, Brent D.; Champion, Duane E.; Swisher, Carl C.

    2015-01-01

    In 2011, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, collected samples for 12 new argon-argon radiometric ages from eastern Snake River Plain olivine tholeiite basalt flows in the subsurface at the Idaho National Laboratory. The core samples were collected from flows that had previously published paleomagnetic data. Samples were sent to Rutgers University for argon-argon radiometric dating analyses.

  16. Titanium nitride nanoparticles for therapeutic applications

    DEFF Research Database (Denmark)

    Guler, Urcan; Kildishev, Alexander V.; Boltasseva, Alexandra;

    2014-01-01

    Titanium nitride nanoparticles exhibit plasmonic resonances in the biological transparency window where high absorption efficiencies can be obtained with small dimensions. Both lithographic and colloidal samples are examined from the perspective of nanoparticle thermal therapy. © 2014 OSA....

  17. Progress in molecular uranium-nitride chemistry

    OpenAIRE

    King, David M.; Liddle, Stephen T

    2014-01-01

    The coordination, organometallic, and materials chemistry of uranium nitride has long been an important facet of actinide chemistry. Following matrix isolation experiments and computational characterisation, molecular, solution-based uranium chemistry has developed significantly in the last decade or so culminating most recently in the isolation of the first examples of long-sought terminal uranium nitride linkages. Herein, the field is reviewed with an emphasis on well-defined molecular spec...

  18. Innovative boron nitride-doped propellants

    OpenAIRE

    Thelma Manning; Richard Field; Kenneth Klingaman; Michael Fair; John Bolognini; Robin Crownover; Carlton P. Adam; Viral Panchal; Eugene Rozumov; Henry Grau; Paul Matter; Michael Beachy; Christopher Holt; Samuel Sopok

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower ...

  19. The Nitrogen-Nitride Anode.

    Energy Technology Data Exchange (ETDEWEB)

    Delnick, Frank M.

    2014-10-01

    Nitrogen gas N 2 can be reduced to nitride N -3 in molten LiCl-KCl eutectic salt electrolyte. However, the direct oxidation of N -3 back to N 2 is kinetically slow and only occurs at high overvoltage. The overvoltage for N -3 oxidation can be eliminated by coordinating the N -3 with BN to form the dinitridoborate (BN 2 -3 ) anion which forms a 1-D conjugated linear inorganic polymer with -Li-N-B-N- repeating units. This polymer precipitates out of solution as Li 3 BN 2 which becomes a metallic conductor upon delithiation. Li 3 BN 2 is oxidized to Li + + N 2 + BN at about the N 2 /N -3 redox potential with very little overvoltage. In this report we evaluate the N 2 /N -3 redox couple as a battery anode for energy storage.

  20. Evolution of Martian atmospheric argon: Implications for sources of volatiles

    Science.gov (United States)

    Hutchins, Kevin S.; Jakosky, Bruce M.

    We have examined processes affecting isotopes of argon (36Ar, 38Ar, 40Ar) in order to determine important atmospheric sources and sinks. Our simple model for argon evolution incorporates production of radiogenic argon in the mantle, outgassing of all argon species by extrusive and intrusive volcanism, and loss to space by knock-on sputtering above the exobase. Sputtering has been shown previously to be an important loss process for atmospheric species, especially isotopes of noble gases, which have few other mechanisms of escape. The integrated evolution of argon (36Ar, 38Ar, and 40Ar, respectively) is modeled in terms of these variables: (1) the planetary concentration of potassium, (2) the fraction of juvenile argon released catastrophically during the first 600 Myr., (3) potential variation in the time-history of sputtering loss from that suggested by Luhmann et al. [1992], and (4) the volume of total outgassing to the surface as compared to outgassing contributed by volcanic release. Our results indicate that Mars has lost between 85-95% of 36Ar and 70-88% of outgassed 40Ar. Due to this substantial loss, the planet must have outgassed the equivalent of between 10 and 100 times the total volume of gases released by extrusive and intrusive volcanics. This indicates that volcanic outgassing, alone, is insufficient to explain the present-day abundances of 36Ar and 40Ar in the Martian atmosphere. Similar calculations for 20Ne suggest outgassed volumes of between 100 and 1800 times in excess of that due to volcanism. This results in a distinct Ne/Ar elemental fractionation, with a preference for outgassing argon, of the order of 10 to 17. Although the results must be evaluated within the model uncertainties, the results are compelling in that they unequivocally show the existence of additional sources of atmospheric volatiles and helps define a means to identify them.

  1. Direct access to macroporous chromium nitride and chromium titanium nitride with inverse opal structure.

    Science.gov (United States)

    Zhao, Weitian; DiSalvo, Francis J

    2015-03-21

    We report a facile synthesis of single-phase, nanocrystalline macroporous chromium nitride and chromium titanium nitride with an inverse opal morphology. The material is characterized using XRD, SEM, HR-TEM/STEM, TGA and XPS. Interconversion of macroporous CrN to Cr2O3 and back to CrN while retaining the inverse opal morphology is also demonstrated.

  2. Synthesis of Vanadium Nitride by a One Step Method

    Institute of Scientific and Technical Information of China (English)

    Sansan YU; Nianxin FU; Feng GAO; Zhitong SUI

    2007-01-01

    Vanadium nitrides were prepared via one step method of carbothermal reduction and nitridation of vanadium trioxide. Thermalgravimetric analysis (TGA) and X-ray diffraction were used to determine the reaction paths of vanadium carbide, namely the following sequential reaction: V2O3→V8C7 in higher temperature stage, the rule of vanadium nitride synthesized was established, and defined conditions of temperature for the production of the carbides and nitrides were determined. Vanadium oxycarbide may consist in the front process of carbothermal reduction of vanadium trioxide. In one step method for vanadium nitride by carbothermal reduction and nitridation of vanadium trioxide, the nitridation process is simultaneous with the carbothermal reduction. A one-step mechanism of the carbothermal reduction with simultaneous nitridation leaded to a lower terminal temperature in nitridation process for vanadium nitride produced, compared with that of carbothermal reduction process without nitridation. The grain size and shape of vanadium nitride were uniform, and had the shape of a cube. The one step method combined vacuum carborization and nitridation (namely two step method) into one process. It simplified the technological process and decreased the costs.

  3. Catalytic growth of vertically aligned neutron sensitive {sup 10}Boron nitride nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Pervaiz, E-mail: pervaizahmad@siswa.um.edu.my, E-mail: Pervaiz-pas@yahoo.com; Khandaker, Mayeen Uddin, E-mail: mu-khandaker@yahoo.com, E-mail: mu-khandaker@um.edu.my; Amin, Yusoff Mohd [University of Malaya, Department of Physics, Faculty of Science (Malaysia); Khan, Ghulamullah [University of Malaya, Department of Mechanical Engineering (Malaysia); Ramay, Shahid M. [King Saud University, Department of Physics and Astronomy, College of Science (Saudi Arabia); Mahmood, Asif [King Saud University, Department of Chemical Engineering, College of Engineering (Saudi Arabia); Amin, Muhammad [University of the Punjab, Department of Physics (Pakistan); Muhammad, Nawshad [Interdisciplinary Research Centre in Biomedical Materials (IRCBM) COMSATS Institute of Information Technology (Pakistan)

    2016-01-15

    {sup 10}Boron nitride nanotubes ({sup 10}BNNTs) are a potential neutron sensing element in a solid-state neutron detector. The aligned {sup 10}BNNT can be used for its potential application without any further purification. Argon-supported thermal CVD is used to achieve vertically aligned {sup 10}BNNT with the help of nucleation sites produced in a thin layer of magnesium–iron alloy deposited at the top of Si substrate. FESEM shows vertically aligned {sup 10}BNNTs with ball-like catalytic tips at top. EDX reveals magnesium (Mg) contents in the tips that refer to catalytic growth of {sup 10}BNNT. HR-TEM shows tubular morphology of the synthesized {sup 10}BNNT with lattice fringes on its outer part having an interlayer spacing of ∼0.34 nm. XPS shows B 1 s and N 1 s peaks at 190.5 and 398 eV that correspond to hexagonal {sup 10}Boron nitride ({sup 10}h-BN) nature of the synthesized {sup 10}BNNT, whereas the Mg kll auger peaks at ∼301 and ∼311 eV represents Mg contents in the sample. Raman spectrum has a peak at 1390 (cm{sup −1}) that corresponds to E{sub 2g} mode of vibration in {sup 10}h-BN.

  4. Catalytic growth of vertically aligned neutron sensitive 10Boron nitride nanotubes

    International Nuclear Information System (INIS)

    10Boron nitride nanotubes (10BNNTs) are a potential neutron sensing element in a solid-state neutron detector. The aligned 10BNNT can be used for its potential application without any further purification. Argon-supported thermal CVD is used to achieve vertically aligned 10BNNT with the help of nucleation sites produced in a thin layer of magnesium–iron alloy deposited at the top of Si substrate. FESEM shows vertically aligned 10BNNTs with ball-like catalytic tips at top. EDX reveals magnesium (Mg) contents in the tips that refer to catalytic growth of 10BNNT. HR-TEM shows tubular morphology of the synthesized 10BNNT with lattice fringes on its outer part having an interlayer spacing of ∼0.34 nm. XPS shows B 1 s and N 1 s peaks at 190.5 and 398 eV that correspond to hexagonal 10Boron nitride (10h-BN) nature of the synthesized 10BNNT, whereas the Mg kll auger peaks at ∼301 and ∼311 eV represents Mg contents in the sample. Raman spectrum has a peak at 1390 (cm−1) that corresponds to E2g mode of vibration in 10h-BN

  5. Adhesion analysis for chromium nitride thin films deposited by reactive magnetron sputtering

    Science.gov (United States)

    Rusu, F. M.; Merie, V. V.; Pintea, I. M.; Molea, A.

    2016-08-01

    The thin film industry is continuously growing due to the wide range of applications that require the fabrication of advanced components such as sensors, biological implants, micro-electromechanical devices, optical coatings and so on. The selection regarding the deposition materials, as well as the deposition technology influences the properties of the material and determines the suitability of devices for certain real-world applications. This paper is focused on the adhesion force for several chromium nitride thin films obtained by reactive magnetron sputtering. All chromium nitride thin films were deposited on a silicon substrate, the discharge current and the argon flow being kept constant. The main purpose of the paper is to determine the influence of deposition parameters on the adhesion force. Therefore some of the deposition parameters were varied in order to study their effect on the adhesion force. Experimentally, the values of the adhesion force were determined in multiple points for each sample using the spectroscopy in point mode of the atomic force microscope. The obtained values were used to estimate the surface energy of the CrN thin films based on two existing mathematical models for the adhesion force when considering the contact between two bodies.

  6. Thermal Plasma Synthesis of Crystalline Gallium Nitride Nanopowder from Gallium Nitrate Hydrate and Melamine

    Directory of Open Access Journals (Sweden)

    Tae-Hee Kim

    2016-02-01

    Full Text Available Gallium nitride (GaN nanopowder used as a blue fluorescent material was synthesized by using a direct current (DC non-transferred arc plasma. Gallium nitrate hydrate (Ga(NO33∙xH2O was used as a raw material and NH3 gas was used as a nitridation source. Additionally, melamine (C3H6N6 powder was injected into the plasma flame to prevent the oxidation of gallium to gallium oxide (Ga2O3. Argon thermal plasma was applied to synthesize GaN nanopowder. The synthesized GaN nanopowder by thermal plasma has low crystallinity and purity. It was improved to relatively high crystallinity and purity by annealing. The crystallinity is enhanced by the thermal treatment and the purity was increased by the elimination of residual C3H6N6. The combined process of thermal plasma and annealing was appropriate for synthesizing crystalline GaN nanopowder. The annealing process after the plasma synthesis of GaN nanopowder eliminated residual contamination and enhanced the crystallinity of GaN nanopowder. As a result, crystalline GaN nanopowder which has an average particle size of 30 nm was synthesized by the combination of thermal plasma treatment and annealing.

  7. Characterisation of GERDA Phase-I detectors in liquid argon

    International Nuclear Information System (INIS)

    GERDA will search for neutrinoless double beta decay in 76Ge by submerging bare enriched HPGe detectors in liquid argon. In GERDA Phase-I, reprocessed enriched-Ge detectors, which were previously operated by the Heidelberg-Moscow and IGEX collaborations, and reprocessed natural-Ge detectors from Genius-TF, will be redeployed. We have tested the operation and performance of bare HPGe detectors in liquid nitrogen and in liquid argon over more than three years with three non-enriched p-type prototype detectors. The detector handling and mounting procedures have been defined and the Phase-I detector technology, the low-mass assembly and the long-term stability in liquid argon have been tested successfully. The Phase-I detectors were reprocessed by Canberra Semiconductor NV, Olen, according to their standard technology but without the evaporation of a passivation layer. After their reprocessing, the detectors have been mounted in their low-mass holders and their characterisation in liquid argon performed. The leakage current, the counting characteristics and the efficiency of the detectors have been measured. The testing of the detectors was carried out in the liquid argon test stand of the GERDA underground Detector Laboratory (GDL) at LNGS. The detectors are now stored underground under vacuum until their operation in GERDA.

  8. The Spectroscopic Detectability of Argon in the Lunar Atmosphere

    CERN Document Server

    Parker, J W; Gladstone, G R; Shull, J M; Parker, Joel Wm.

    1999-01-01

    Direct measurements of the abundance of argon in the lunar atmosphere were made in 1973 by instruments placed on the Moon during the Apollo 17 mission, but the total daytime abundance is unknown due to instrument saturation effects; thus, until we are able to return to the Moon for improved direct measurements, we must use remote sensing to establish the daytime abundance. In this paper, we present a complete analysis of the potential for measuring argon in the lunar atmosphere via emission-line or absorption-line observations. We come to the surprising conclusion that the lower limit established by the in situ lunar argon measurements implies that any absorption-line measurement of argon in the lower, dayside lunar atmosphere requires analysis in the optically-thick regime. In light of this result, we present the results of our EUVS sounding rocket observations of the lunar occultation of Spica, which provide a new upper limit on the abundance of argon in the daytime lunar atmosphere. We also re-analyze a re...

  9. Growth of epitaxial iron nitride ultrathin film on zinc-blende gallium nitride

    International Nuclear Information System (INIS)

    The authors report the growth of iron nitride on zinc-blende gallium nitride using molecular beam epitaxy. First, zinc-blende GaN is grown on a magnesium oxide substrate having (001) orientation; second, an ultrathin layer of FeN is grown on top of the GaN layer. In situ reflection high-energy electron diffraction is used to monitor the surface during growth, and a well-defined epitaxial relationship is observed. Cross-sectional transmission electron microscopy is used to reveal the epitaxial continuity at the gallium nitride-iron nitride interface. Surface morphology of the iron nitride, similar to yet different from that of the GaN substrate, can be described as plateau valley. The FeN chemical stoichiometry is probed using both bulk and surface sensitive methods, and the magnetic properties of the sample are revealed.

  10. Influence of the power on the processes controlling the formation of ECR-CVD carbon nitride films from CH{sub 4}/Ar/N{sub 2} plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Camero, M [Instituto de Ciencia de Materiales de Madrid (CSIC), 28049 Madrid (Spain); Gordillo-Vazquez, F J [Instituto de Optica (CSIC), Serrano 121, 28006 Madrid (Spain); Ortiz, J [Instituto de Ciencia de Materiales de Madrid (CSIC), 28049 Madrid (Spain); Gomez-Aleixandre, C [Instituto de Ciencia de Materiales de Madrid (CSIC), 28049 Madrid (Spain)

    2004-02-01

    Carbon nitride films have been synthesized by means of electron cyclotron resonance chemical vapour deposition (ECR-CVD) using different power values (50-212 W) at constant pressure conditions (0.03 mbar). Optical emission spectroscopy and mass spectrometry were used for the characterization of the plasma. The films were analysed using energy dispersive x-ray spectroscopies. It was found that all signal peaks in the optical emission spectra increased monotonically following the increase in microwave power. Moreover, we have observed that the radiative emission from the 4p({sup 2}p{sub 9}) resonant state of Ar is the most affected by CH{sub 4} addition to a pure argon plasma. The latter suggests that a Penning mechanism controls the activation of CH{sub 4} molecules with increasing power levels at relatively low pressures. Besides, the increase of excited N atoms indicates a higher activity of the etching mechanisms of carbon nitride films with increasing power.

  11. Nitriding and Nitrocarburizing; Current Status and Future Challenges

    DEFF Research Database (Denmark)

    Somers, Marcel A. J.

    This contribution addresses the current understanding of gaseous nitriding and nitrocarburizing. Aspects of thermodynamics, kinetics and microstructure development in iron and heat treatable steel will be explained. In these materials the nitrided/ nitrocarburized case can be subdivided...

  12. Method of manufacture of atomically thin boron nitride

    Science.gov (United States)

    Zettl, Alexander K

    2013-08-06

    The present invention provides a method of fabricating at least one single layer hexagonal boron nitride (h-BN). In an exemplary embodiment, the method includes (1) suspending at least one multilayer boron nitride across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure. The present invention also provides a method of fabricating single layer hexagonal boron nitride. In an exemplary embodiment, the method includes (1) providing multilayer boron nitride suspended across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure.

  13. Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties and Applications

    DEFF Research Database (Denmark)

    Guler, Urcan; Suslov, Sergey; Kildishev, Alexander V.;

    2015-01-01

    Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal and photocatalytic applications via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average ...

  14. Metastable argon beam source using a surface wave sustained plasma

    International Nuclear Information System (INIS)

    A new source of metastable argon atoms in the thermal energy range is reported. The source is based on expanding a plasma sustained by electromagnetic surface waves in a quartz tube through a converging nozzle and extracting a beam from the supersonic free-expansion jet. The beam was characterized by time-of-flight measurements which yielded the absolute intensity and velocity distribution of the argon metastables. The source produced a maximum intensity of 6.2x1014 metastables per second per steradian, the highest time-averaged intensity of thermal argon metastables of any source reported to date. A simple picture of an expanding plasma in a recombination regime is used to explain the dependence of the metastable intensity on absorbed power

  15. On the electric breakdown in liquid argon at centimeter scale

    Science.gov (United States)

    Auger, M.; Blatter, A.; Ereditato, A.; Goeldi, D.; Janos, S.; Kreslo, I.; Luethi, M.; von Rohr, C. Rudolf; Strauss, T.; Weber, M. S.

    2016-03-01

    We present a study on the dependence of electric breakdown discharge properties on electrode geometry and the breakdown field in liquid argon near its boiling point. The measurements were performed with a spherical cathode and a planar anode at distances ranging from 0.1 mm to 10.0 mm. A detailed study of the time evolution of the breakdown volt-ampere characteristics was performed for the first time. It revealed a slow streamer development phase in the discharge. The results of a spectroscopic study of the visible light emission of the breakdowns complement the measurements. The light emission from the initial phase of the discharge is attributed to electro-luminescence of liquid argon following a current of drifting electrons. These results contribute to set benchmarks for breakdown-safe design of ionization detectors, such as Liquid Argon Time Projection Chambers (LAr TPC).

  16. The Simulation of the ATLAS Liquid Argon Calorimetry

    CERN Document Server

    Archambault, J P; Carli, T; Costanzo, D; Dell'Acqua, A; Djama, F; Gallas, M; Fincke-Keeler, M; Khakzad, M; Kiryunin, A; Krieger, P; Leltchouk, M; Loch, P; Ma, H; Menke, S; Monnier, E; Nairz, A; Niess, V; Oakham, G; Oram, C; Pospelov, G; Rajagopalan, S; Rimoldi, A; Rousseau, D; Rutherfoord, J; Seligman, W; Soukharev, A; Strízenec, P; Tóth, J; Tsukerman, I; Tsulaia, V; Unal, G; Grahn, K J

    2008-01-01

    In ATLAS, all of the electromagnetic calorimetry and part of the hadronic calorimetry is performed by a calorimeter system using liquid argon as the active material, together with various types of absorbers. The liquid argon calorimeter consists of four subsystems: the electromagnetic barrel and endcap accordion calorimeters; the hadronic endcap calorimeters, and the forward calorimeters. A very accurate geometrical description of these calorimeters is used as input to the Geant 4-based ATLAS simulation, and a careful modelling of the signal development is applied in the generation of hits. Certain types of Monte Carlo truth information ("Calibration Hits") may, additionally, be recorded for calorimeter cells as well as for dead material. This note is a comprehensive reference describing the simulation of the four liquid argon calorimeteter components.

  17. Energy resolution studies of liquid argon ionization detectors

    International Nuclear Information System (INIS)

    A gridded ionization chamber was used to study the energy resolution in liquid argon with electrons from a 207Bi radioactive source. Argon was purified in the gas phase with a simple and reliable system, capable of reducing the impurity level below 1 ppb O2 equivalent, as inferred by a pulse shape analysis of the ionization signals. The electron spectrum was measured at different drift fields, up to 10.9 KV/cm. At this maximum field, a total energy resolution of 32 keV (fwhm), corresponding to a noise-subtracted energy resolution of 26 keV (fwhm), was obtained for the 976 keV conversion electron line. This value is the best reported so far in liquid argon but is still a factor of seven worse than the theoretical limit set by the Fano factor. The reasons for this discrepancy are discussed. (orig.)

  18. Liquid Argon Calorimetry with LHC-Performance Specifications

    CERN Multimedia

    2002-01-01

    % RD-3 Liquid Argon Calorimetry with LHC-Performance Specifications \\\\ \\\\Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. Among the techniques used so far, or under development, the liquid argon sampling calorimetry offers high radiation resistence, good energy resolution (electromagnetic and hadronic), excellent calibration stability and response uniformity. Its rate capabilities, however, do not yet match the requirements for LHC. \\\\ \\\\The aim of this proposal is to improve the technique in such a way that high granularity, good hermiticity and adequate rate capabilities are obtained, without compromising the above mentioned properties. To reach this goal, we propose to use a novel structure, the $^{\\prime\\prime}$accordion$^{\\prime\\prime}$, coupled to fast preamplifiers working at liquid argon temperature. Converter and readout electrodes are no longer planar and perpendicular to particles, as usual, but instead they are wiggled around a plane containing particles. ...

  19. A therapeutic experience on Port Wine hemangiomas with Argon Laser

    Directory of Open Access Journals (Sweden)

    Farahvash M

    1997-09-01

    Full Text Available Port wine stains are benign but cosmetically devasting congenital angiomas. The argon laser is a therapeutic device newly applied to this condition. Our program was begun 6 years ago. From the beginning, the study was conceived as a clinical investigation of both the port wine stain and its argon laser therapy. A total of 218 patients with port wine stains have been studied and many aspects of their clinical condition detailed. Employing the Argon laser, test spots have been carried out in patients and the results have been analyzed with clinical aspects of the lesions. Altogether, 501 treatments were performed in 218 patients. Good to excellent results were obtained in 81 patients. Moderate Result was obtained in 31 weak result in 65 patients. Most common complication were hyperpigmentation and depressed scar.

  20. On the Electric Breakdown in Liquid Argon at Centimeter Scale

    CERN Document Server

    Auger, M; Ereditato, A; Goeldi, D; Janos, S; Kreslo, I; Luethi, M; von Rohr, C Rudolf; Strauss, T; Weber, M S

    2015-01-01

    We present a study on the dependence of electric breakdown discharge parameters on electrode geometry and the breakdown field in liquid argon near its boiling point. The measurements were performed with a spherical cathode and a planar anode at distances ranging from 0.1 mm to 10.0 mm. A detailed study of the time evolution of the breakdown volt-ampere characteristics was performed for the first time. It revealed a slow streamer development phase in the discharge. The results of a spectroscopic study of the visible light emission of the breakdowns complement the measurements. The light emission from the initial phase of the discharge is attributed to electro-luminescence of liquid argon following a current of drifting electrons. These results contribute to set benchmarks for breakdown-safe design of ionization detectors, such as Liquid Argon Time Projection Chambers (LAr TPC).

  1. Advancing liquid metal reactor technology with nitride fuels

    International Nuclear Information System (INIS)

    A review of the use of nitride fuels in liquid metal fast reactors is presented. Past studies indicate that both uranium nitride and uranium/plutonium nitride possess characteristics that may offer enhanced performance, particularly in the area of passive safety. To further quantify these effects, the analysis of a mixed-nitride fuel system utilizing the geometry and power level of the US Advanced Liquid Metal Reactor as a reference is described. 18 refs., 2 figs., 2 tabs

  2. Diffusion kinetics of nitrogen in tantalum during plasma-nitriding

    Institute of Scientific and Technical Information of China (English)

    张德元; 林勤; 曾卫军; 李放; 许兰萍; 付青峰

    2001-01-01

    The activation energies of nitrogen in tantalum on plasma nitriding conditions were calculated according to the experimental data of hardness of plasma-nitriding of tantalum vs time and temperature. The activation energy calculated is 148.873±0.390  kJ/mol. The depth increasing of nitriding layer with time follows square root relation. The nitriding process of tantalum is controlled by diffusion of nitrogen atoms in tantalum solid solution.

  3. Vaporization kinetics of Sb2S3 in argon fluid

    Institute of Scientific and Technical Information of China (English)

    杨勇; 华一新

    2003-01-01

    The vaporization kinetics of antimony trisulfide in argon fluid was studied with thermogravimetry at 873- 1 173 K. A theoretical model was developed to calculate the overall rate constant and the mass transfer coefficient ingas phase. The experimental results show that the vaporization rate is enhanced with increasing temperature and ar-gon flow-rate. The evaporation rate is mainly controlled by mass transport in the gas phase. The apparent activationenergy for the process is found to be 55.54 kJ/mol. It is demonstrated that the mass transfer coefficient in gas phaseis decreased with increasing temperature.

  4. Modelling of a supersonic ICP argon-hydrogen expansion

    International Nuclear Information System (INIS)

    An expanding argon-hydrogen plasma is investigated by means of simulations. The model is a hydrodynamical model specific for plasma expansions, taking into account the conservation laws of mass, momentum and energy. The code includes the Rankine-Hugoniot relations to calculate shock jump conditions. Results are shown for the expansion from an inductively coupled plasma (ICP) with a separated Laval nozzle. The expansion discussed here is a 'weakly' under-expanding argon-hydrogen plasma. The results from the ICP expansion are verified with probe measurements

  5. Attosecond-correlated dynamics of two electrons in argon

    Indian Academy of Sciences (India)

    V Sharma; N Camus; B Fischer; M Kremer; A Rudenko; B Bergues; M Kuebel; N G Johnson; M F Kling; T Pfeifer; J Ullrich; R Moshammer

    2014-01-01

    In this work we explored strong field-induced decay of doubly excited transient Coulomb complex Ar** → Ar2++2. We measured the correlated two-electron emission as a function of carrier envelop phase (CEP) of 6 fs pulses in the non-sequential double ionization (NSDI) of argon. Classical model calculations suggest that the intermediate doubly excited Coulomb complex loses memory of its formation dynamics. We estimated the ionization time difference between the two electrons from NSDI of argon and it is 200 ± 100 as (N Camus et al, Phys. Rev. Lett. 108, 073003 (2012)).

  6. Studies on Dielectric Properties of Silicon Nitride at High Temperature

    Institute of Scientific and Technical Information of China (English)

    Ting Zhang; Shu-Ren Zhang; Meng-Qiang Wu; Wei-Jun Sang; Zheng-Ping Gao; Zhong-Ping Li

    2007-01-01

    In this paper, the dielectric properties of silicon nitride are studied using the dielectric polarization theories. According to the developed dielectric models, the temperature dependence of dielectric constant and loss of silicon nitride is mainly analyzed. In addition, the impact of Li+, K+, Ca2+, Al3+ and Mg2+ doping on the dielectric properties of silicon nitride are also estimated.

  7. Ion nitriding in 316=L stainless steel

    International Nuclear Information System (INIS)

    Ion nitriding is a glow discharge process that is used to induce surface modification in metals. It has been applied to 316-L austenitic stainless steel looking for similar benefits already obtained in other steels. An austenitic stainless steel was selected because is not hardenable by heat treatment and is not easy to nitride by gas nitriding. The samples were plastically deformed to 10, 20, 40, 50 AND 70% of their original thickness in order to obtain bulk hardening and to observe nitrogen penetration dependence on it. The results were: an increase of one to two rockwell hardness number (except in 70% deformed sample because of its thickness); an increase of even several hundreds per cent in microhardness knoop number in nitrided surface. The later surely modifies waste resistance which would be worth to quantify in further studies. Microhardness measured in an internal transversal face to nitrided surface had a gradual diminish in its value with depth. Auger microanalysis showed a higher relative concentration rate CN/CFe near the surface giving evidence of nitrogen presence till 250 microns deep. The color metallography etchant used, produced faster corrosion in nitrited regions. Therefore, corrosion studies have to be done before using ion nitrited 316-L under these chemicals. (Author)

  8. Innovative boron nitride-doped propellants

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2016-04-01

    Full Text Available The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P. Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  9. Innovative boron nitride-doped propellants

    Institute of Scientific and Technical Information of China (English)

    Thelma MANNING; Henry GRAU; Paul MATTER; Michael BEACHY; Christopher HOLT; Samuel SOPOK; Richard FIELD; Kenneth KLINGAMAN; Michael FAIR; John BOLOGNINI; Robin CROWNOVER; Carlton P. ADAM; Viral PANCHAL; Eugene ROZUMOV

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  10. Uranium-liquid argon calorimetry: preliminary results from the DO tests

    International Nuclear Information System (INIS)

    The motivations for using uranium and liquid argon in sampling calorimetry are reviewed and the pros and cons of the technique are discussed. Preliminary results of the DO uranium-liquid argon test program are presented. 9 refs., 7 figs

  11. Permeation barrier performance of Hot Wire-CVD grown silicon-nitride films treated by argon plasma

    OpenAIRE

    Majee, S.; Cerqueira, M. F.; Tondelier, D.; Vanel, J. C.; Geffroy, B.; Bonnassieux, Y.; Alpuim, P.; Bourée, J. E.

    2015-01-01

    In this work SiNx thin films have been deposited by Hot-Wire Chemical Vapor Deposition (HW-CVD) technique to be used as encapsulation barriers for flexible organic electronic devices fabricated on polyethylene terephthalate (PET) substrates. First results of SiNx multilayers stacked and stacks of SiNx single-layers (50 nm each) separated by an Ar-plasma surface treatment are reported. The encapsulation barrier properties of these different multilayers are assessed using the electrical calcium...

  12. Fusion bonding of silicon nitride surfaces

    DEFF Research Database (Denmark)

    Reck, Kasper; Østergaard, Christian; Thomsen, Erik Vilain;

    2011-01-01

    While silicon nitride surfaces are widely used in many micro electrical mechanical system devices, e.g. for chemical passivation, electrical isolation or environmental protection, studies on fusion bonding of two silicon nitride surfaces (Si3N4–Si3N4 bonding) are very few and highly application...... results on bonding of thin and thick Si3N4 layers. The new results include high temperature bonding without any pretreatment, along with improved bonding ability achieved by thermal oxidation and chemical pretreatment. The bonded wafers include both unprocessed and processed wafers with a total silicon...... nitride thickness of up to 440 nm. Measurements of bonding strength, void characterization, oxidation rate and surface roughness are also presented. Bonding strengths for stoichiometric low pressure chemical vapor deposition Si3N4–Si3N4 direct fusion bonding in excess of 2 J cm−2 are found...

  13. Nitride Fuel Development at the INL

    Energy Technology Data Exchange (ETDEWEB)

    W.E. Windes

    2007-06-01

    A new method for fabricating nitride-based fuels for nuclear applications is under development at the Idaho National Laboratory (INL). A primary objective of this research is the development of a process that could be operated as an automated or semi-automated technique reducing costs, worker doses, and eventually improving the final product form. To achieve these goals the fabrication process utilizes a new cryo-forming technique to produce microspheres formed from sub-micron oxide powder to improve material handling issues, yield rapid kinetics for conversion to nitrides, and reduced material impurity levels within the nitride compounds. The microspheres are converted to a nitride form within a high temperature particle fluidizing bed using a carbothermic process that utilizes a hydrocarbon – hydrogen - nitrogen gas mixture. A new monitor and control system using differential pressure changes in the fluidizing gas allows for real-time monitoring and control of the spouted bed reactor during conversion. This monitor and control system can provide real-time data that is used to control the gas flow rates, temperatures, and gas composition to optimize the fluidization of the particle bed. The small size (0.5 µm) of the oxide powders in the microspheres dramatically increases the kinetics of the conversion process yielding reduced process times and temperatures. Initial studies using surrogate ZrO2 powder have yielded conversion efficiencies of 90 -95 % nitride formation with only small levels of oxide and carbide contaminants present. Further studies are being conducted to determine optimal gas mixture ratios, process time, and temperature range for providing complete conversion to a nitride form.

  14. Nitride Fuel Development at the INL

    International Nuclear Information System (INIS)

    A new method for fabricating nitride-based fuels for nuclear applications is under development at the Idaho National Laboratory (INL). A primary objective of this research is the development of a process that could be operated as an automated or semi-automated technique reducing costs, worker doses, and eventually improving the final product form. To achieve these goals the fabrication process utilizes a new cryo-forming technique to produce microspheres formed from sub-micron oxide powder to improve material handling issues, yield rapid kinetics for conversion to nitrides, and reduced material impurity levels within the nitride compounds. The microspheres are converted to a nitride form within a high temperature particle fluidizing bed using a carbothermic process that utilizes a hydrocarbon-hydrogen-nitrogen gas mixture. A new monitor and control system using differential pressure changes in the fluidizing gas allows for real-time monitoring and control of the spouted bed reactor during conversion. This monitor and control system can provide real-time data that is used to control the gas flow rates, temperatures, and gas composition to optimize the fluidization of the particle bed. The small size (0.5 (micro)m) of the oxide powders in the microspheres dramatically increases the kinetics of the conversion process yielding reduced process times and temperatures. Initial studies using surrogate ZrO2 powder have yielded conversion efficiencies of 90-95% nitride formation with only small levels of oxide and carbide contaminants present. Further studies are being conducted to determine optimal gas mixture ratios, process time, and temperature range for providing complete conversion to a nitride form

  15. Optical emission spectroscopy of argon and hydrogen-containing plasmas

    Science.gov (United States)

    Siepa, Sarah; Danko, Stephan; Tsankov, Tsanko V.; Mussenbrock, Thomas; Czarnetzki, Uwe

    2015-09-01

    Optical emission spectroscopy (OES) on neutral argon is applied to investigate argon, hydrogen and hydrogen-silane plasmas. The spectra are analyzed using an extensive collisional-radiative model (CRM), from which the electron density and the electron temperature (or mean energy) can be calculated. The CRM also yields insight into the importance of different excited species and kinetic processes. The OES measurements are performed on pure argon plasmas at intermediate pressure. Besides, hydrogen and hydrogen-silane plasmas are investigated using argon as a trace gas. Especially for the gas mixture discharges, CRMs for low and high pressure differ substantially. The commonly used line-ratio technique is found to lose its sensitivity for gas mixture discharges at higher pressure. A solution using absolutely calibrated line intensities is proposed. The effect of radiation trapping and the shape of the electron energy distribution function on the results are discussed in detail, as they have been found to significantly influence the results. This work was supported by the Ruhr University Research School PLUS, funded by Germany's Excellence Initiative [DFG GSC 98/3].

  16. Measurement of the argon plasma temperature by use of pyrometer

    International Nuclear Information System (INIS)

    The author describes in detail how to use pyrometer to measure the plasma temperature. The temperatures of shock-generated argon plasmas are given in the present work. Measured results of temperature-pressure curve are compared with calculated results using Saha-Debye-Huckel model, which are in good agreement

  17. Turbulence and transport in a magnetized argon plasma

    International Nuclear Information System (INIS)

    An experimental study on turbulence and transport in the highly ionized argon plasma of a hollow cathode discharge is described. In order to determine the plasma parameters three standard diagnostics have been used, whilst two diagnostics have been developed to study the plasma turbulence. (Auth.)

  18. Thermophysical properties of multi-shock compressed dense argon.

    Science.gov (United States)

    Chen, Q F; Zheng, J; Gu, Y J; Chen, Y L; Cai, L C; Shen, Z J

    2014-02-21

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models. PMID:24559345

  19. Thermal decomposition of Yttrium(III) isovalerate in argon

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Yue, Zhao; Tang, Xiao;

    2016-01-01

    The thermal behaviour of yttrium(III) isovalerate (Y(C4H9CO2)3) was studied in argon by means of thermogravimetry, differential thermal analysis, FTIR-spectroscopy, hot-stage optical microscopy and X-ray diffraction with a laboratory Cu-tube source as well as with a synchrotron radiation source...

  20. Thermal decomposition of yttrium(III) valerate in argon

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Yue, Zhao; Tang, Xiao;

    2014-01-01

    The thermal decomposition of yttrium(III) valerate (Y(C4H9CO2)3) was studied in argon by means of thermogravimetry, differential thermal analysis, IR-spectroscopy, X-ray diffraction, in-situ synchrotron diffraction and hot-stage microscopy as well as room temperature optical microscopy. Melting...

  1. Thermal decomposition of yttrium(III) hexanoate in argon

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Suarez Guevara, Maria Josefina; Attique, Fahmida;

    2015-01-01

    The thermal decomposition of yttrium(III) hexanoate (Y(C5H11CO2)3)·xH2O in argon was studied by means of thermogravimetry, differential thermal analysis, IR-spectroscopy, X-ray diffraction at a laboratory Cu-tube source and in-situ experiments at a synchrotron radiation source as well as hot...

  2. A 2-Dimensional Fluid Model for an Argon Rf Discharge

    NARCIS (Netherlands)

    Passchier, J. D. P.; W. J. Goedheer,

    1993-01-01

    A fluid model for an argon rf discharge in a cylindrical discharge chamber is presented. The model contains the particle balances for electrons and ions and the electron energy balance. A nonzero autobias voltage is obtained by imposing the condition that the time-averaged current toward the powered

  3. Study of Liquid Argon Dopants for LHC Hadron Calorimetry

    CERN Multimedia

    2002-01-01

    Hadron calorimetry based on the Liquid Argon Ionisation Chamber technique is one of the choice techniques for LHC-experimentation. A systematic study of the effect of selected dopants on Liquid Argon (LAr) will be carried out with the aim to achieve an improvement on: \\item (i)~``Fast Liquid Argon'' search and study of dopants to increase the drift velocity. It has been already shown that CH&sub4. added at a fraction of one percent increases the drift velocity by a factor of two or more. \\item (ii)~``Compensated Liquid Argon'' search and study of dopants to increase the response to densely ionising particles, resulting in improved compensation, such as photosensitive dopants. \\end{enumerate}\\\\ \\\\ Monitoring of the parameters involved in understanding the response of a calorimeter is essential. In case of doped LAr, the charge yield, the non-saturated drift velocity and the electron lifetime in the liquid should be precisely and simultaneously monitored as they all vary with the level of dopant concentrati...

  4. LArGe. A liquid argon scintillation veto for GERDA

    International Nuclear Information System (INIS)

    LArGe is a GERDA low-background test facility to study novel background suppression methods in a low-background environment, for possible applications in the GERDA experiment. GERDA searches for the neutrinoless double-beta decay in 76Ge, by operating naked germanium detectors submersed into 65 m3 of liquid argon. Similarly, LArGe runs Ge-detectors in 1 m3 (1.4 tons) of liquid argon, which in addition is instrumented with photomultipliers to detect argon scintillation light. The light is used in anti-coincidence with the germanium detectors, to effectively suppress background events that deposit energy in the liquid argon. This work adresses the design, construction, and commissioning of LArGe. The background suppression efficiency has been studied in combination with a pulse shape discrimination (PSD) technique for various sources, which represent characteristic backgrounds to GERDA. Suppression factors of a few times 103 have been achieved. First background data of LArGe (without PSD) yield a background index of (0.12-4.6).10-2 cts/(keV.kg.y) (90% c.l.), which is at the level of the Gerda phase I design goal. Furthermore, for the first time we measure the natural 42Ar abundance (in parallel to Gerda), and have indication for the 2νββ-decay in natural germanium. (orig.)

  5. LArGe. A liquid argon scintillation veto for GERDA

    Energy Technology Data Exchange (ETDEWEB)

    Heisel, Mark

    2011-04-13

    LArGe is a GERDA low-background test facility to study novel background suppression methods in a low-background environment, for possible applications in the GERDA experiment. GERDA searches for the neutrinoless double-beta decay in {sup 76}Ge, by operating naked germanium detectors submersed into 65 m{sup 3} of liquid argon. Similarly, LArGe runs Ge-detectors in 1 m{sup 3} (1.4 tons) of liquid argon, which in addition is instrumented with photomultipliers to detect argon scintillation light. The light is used in anti-coincidence with the germanium detectors, to effectively suppress background events that deposit energy in the liquid argon. This work adresses the design, construction, and commissioning of LArGe. The background suppression efficiency has been studied in combination with a pulse shape discrimination (PSD) technique for various sources, which represent characteristic backgrounds to GERDA. Suppression factors of a few times 10{sup 3} have been achieved. First background data of LArGe (without PSD) yield a background index of (0.12-4.6).10{sup -2} cts/(keV.kg.y) (90% c.l.), which is at the level of the Gerda phase I design goal. Furthermore, for the first time we measure the natural {sup 42}Ar abundance (in parallel to Gerda), and have indication for the 2{nu}{beta}{beta}-decay in natural germanium. (orig.)

  6. Design of capsules capable of argon-filling

    International Nuclear Information System (INIS)

    The possibility of the use of polycarbosilane capsules as fuel container in inertial confinement fusion experiments was analyzed in the paper. Primary study indicates that the polycarbosilane capsules can be filled with argon by means of diffusion and possess reasonable retention time for deuterium. (author)

  7. Precipitate-Accommodated Plasma Nitriding for Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Patama Visittipitukul; Tatsuhiko Aizawa; Hideyuki Kuwahara

    2004-01-01

    Reliable surface treatment has been explored to improve the strength and wear resistance of aluminum alloy parts in automotives. Long duration time as well as long pre-sputtering time are required for plasma nitriding of aluminum or its alloys only with the thickness of a few micrometers. New plasma inner nitriding is proposed to realize the fast-rate nitriding of aluminum alloys. Al-6Cu alloy is employed as a targeting material in order to demonstrate the effectiveness of this plasma nitriding. Mechanism of fast-rate nitriding process is discussed with consideration of the role of Al2Cu precipitates.

  8. Conversion of an atomic to a molecular argon ion and low pressure argon relaxation

    Science.gov (United States)

    M, N. Stankov; A, P. Jovanović; V, Lj Marković; S, N. Stamenković

    2016-01-01

    The dominant process in relaxation of DC glow discharge between two plane parallel electrodes in argon at pressure 200 Pa is analyzed by measuring the breakdown time delay and by analytical and numerical models. By using the approximate analytical model it is found that the relaxation in a range from 20 to 60 ms in afterglow is dominated by ions, produced by atomic-to-molecular conversion of Ar+ ions in the first several milliseconds after the cessation of the discharge. This conversion is confirmed by the presence of double-Gaussian distribution for the formative time delay, as well as conversion maxima in a set of memory curves measured in different conditions. Finally, the numerical one-dimensional (1D) model for determining the number densities of dominant particles in stationary DC glow discharge and two-dimensional (2D) model for the relaxation are used to confirm the previous assumptions and to determine the corresponding collision and transport coefficients of dominant species and processes. Project supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant No. ON171025).

  9. Local heating with titanium nitride nanoparticles

    DEFF Research Database (Denmark)

    Guler, Urcan; Ndukaife, Justus C.; Naik, Gururaj V.;

    2013-01-01

    We investigate the feasibility of titanium nitride (TiN) nanoparticles as local heat sources in the near infrared region, focusing on biological window. Experiments and simulations provide promising results for TiN, which is known to be bio-compatible.......We investigate the feasibility of titanium nitride (TiN) nanoparticles as local heat sources in the near infrared region, focusing on biological window. Experiments and simulations provide promising results for TiN, which is known to be bio-compatible....

  10. Alkaline Capacitors Based on Nitride Nanoparticles

    Science.gov (United States)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  11. Observations of acoustic-wave-induced superluminescence in an argon plasma

    International Nuclear Information System (INIS)

    It is shown that in an argon discharge plasma it is possible to obtain overpopulation of certain electronic levels of atomic argon under the influence of acoustic waves. When the specified threshold is exceeded, then a superluminescence (in the form of light flashes) from the overpopulated electronic levels of atomic argon is observed

  12. 21 CFR 874.4490 - Argon laser for otology, rhinology, and laryngology.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Argon laser for otology, rhinology, and laryngology. 874.4490 Section 874.4490 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... Argon laser for otology, rhinology, and laryngology. (a) Identification. The argon laser device for...

  13. Argon metastable dynamics and lifetimes in a direct current microdischarge

    Science.gov (United States)

    Stefanović, Ilija; Kuschel, Thomas; Schröter, Sandra; Böke, Marc

    2014-09-01

    In this paper we study the properties of a pulsed dc microdischarge with the continuous flow of argon. Argon metastable lifetimes are measured by tunable diode laser absorption spectroscopy (TDLAS) and are compared with calculated values which yield information about excitation and de-excitation processes. By increasing the gas flow-rate about 5 times from 10 to 50 sccm, the Arm lifetime increases from 1 to 5 μs due to the reduction of metastable quenching with gas impurities. Optical emission spectroscopy reveals nitrogen and water molecules as the main gas impurities. The estimated N2 density [N2] = 0.1% is too low to explain the measured metastable lifetimes. Water impurity was found to be the main de-excitation source of argon metastable atoms due to high quenching coefficients. The water impurity level of [H2O] = 0.15% to 1% is sufficient to bring calculated metastable lifetimes in line with experiments. The maximum value of water content in the discharge compared to the argon atoms is estimated to approximately 6%, due to the large surface to volume ratio of the microdischarge. The current pulse releases the water molecules from the electrode surface and they are either re-adsorbed in the time between 0.4 ms for [H2O] = 1% and 2.6 ms for [H2O] = 0.15% or pumped out of the discharge with the speed equal to the gas flow-rate. Depending on its partial pressure, the water impurity re-adsorption time is of the order of magnitude or less then the argon gas residence time.

  14. Boron Nitride Nanotubes for Spintronics

    Directory of Open Access Journals (Sweden)

    Kamal B. Dhungana

    2014-09-01

    Full Text Available With the end of Moore’s law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT, which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics.

  15. Boron nitride nanotubes for spintronics.

    Science.gov (United States)

    Dhungana, Kamal B; Pati, Ranjit

    2014-01-01

    With the end of Moore's law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR) effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT), which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics. PMID:25248070

  16. Graphitic Carbon Nitride Supported Catalysts for Polymer Electrolyte Fuel Cells.

    Science.gov (United States)

    Mansor, Noramalina; Jorge, A Belen; Corà, Furio; Gibbs, Christopher; Jervis, Rhodri; McMillan, Paul F; Wang, Xiaochen; Brett, Daniel J L

    2014-04-01

    Graphitic carbon nitrides are investigated for developing highly durable Pt electrocatalyst supports for polymer electrolyte fuel cells (PEFCs). Three different graphitic carbon nitride materials were synthesized with the aim to address the effect of crystallinity, porosity, and composition on the catalyst support properties: polymeric carbon nitride (gCNM), poly(triazine) imide carbon nitride (PTI/Li(+)Cl(-)), and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion testing, all graphitic carbon nitride materials are found to be more electrochemically stable compared to conventional carbon black (Vulcan XC-72R) with B-gCNM support showing the best stability. For the supported catalysts, Pt/PTI-Li(+)Cl(-) catalyst exhibits better durability with only 19% electrochemical surface area (ECSA) loss versus 36% for Pt/Vulcan after 2000 scans. Superior methanol oxidation activity is observed for all graphitic carbon nitride supported Pt catalysts on the basis of the catalyst ECSA.

  17. Study of the nitrides formation in the ionic nitriding process of zircaloy-2 zirconium alloy

    International Nuclear Information System (INIS)

    Zircaloy and Zr-Sn alloys are used in nuclear techniques because they show a very low effective absorption section for neutrons and a high corrosion resistance. This paper shows that by ionic nitriding of Zircaloy type alloys, a structure is obtained that enhances the wear resistance. From the study of the N2/H2 ratio on the nitride quantity formed by ion nitriding of Zircaloy-2 alloy, it can be concluded that the gaseous mixtures with high nitrogen and hydrogen content used in discharge are not favourable in the nitride forming process. The optimum ratio is 1/1. The ZrN superficial layer hardness was checked according to the exposure time and to the layer thickness. (J.S.). 6 refs., 4 figs., 2 tabs

  18. Optimization of processing temperature in the nitridation process for the synthesis of iron nitride nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rohith Vinod, K.; Sakar, M.; Balakumar, S., E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Chennai-600025 (India); Saravanan, P. [Defence Metallurgical Research Laboratory, Hyderabad-500058 (India)

    2015-06-24

    We have demonstrated an effective strategy on the nitridation process to synthesize ε-Fe{sub 3}N nanoparticles (NPs) from the zero valent iron NPs as a starting material. The transformation of iron into iron nitride phase was systematically studied by performing the nitridation process at different processing temperatures. The phase, crystal structure was analyzed by XRD. Morphology and size of the ZVINPs and ε-Fe{sub 3}N NPs were analyzed by field emission scanning electron microscope. Further, their room temperature magnetic properties were studied by using vibrating sample magnetometer and it revealed that the magnetic property of ε-Fe{sub 3}N is associated with ratio of Fe-N in the iron nitride system.

  19. EFFECTS OF ARGON ON THE PROPERTIES OF RF SPUTTERED AMORPHOUS SILICON

    OpenAIRE

    Shao-Qi, Peng; Qai, Yu; Xian, Zhang; Jing, Ye

    1981-01-01

    The Effects of argon on the properties of rf sputtered amorphous silicon film have been investigated. As the sputtering argon pressure is increased from 2 to 20 mTorr, the content of argon in the amorphous silicon film increases apparently (Argon/Silicon : from 10-2 to 5 x 10-2). The other properties measured as a function of argon pressure PAr show that as the PAr is increased, the photoconductivity, resistivity (300K), conductivity activation energy and optical gap increase also, while the ...

  20. Residual Stress Induced by Nitriding and Nitrocarburizing

    DEFF Research Database (Denmark)

    Somers, Marcel A.J.

    2005-01-01

    The present chapter is devoted to the various mechanisms involved in the buildup and relief of residual stress in nitrided and nitrocarburized cases. The work presented is an overview of model studies on iron and iron-based alloys. Subdivision is made between the compound (or white) layer...

  1. Styrene Aziridination by Iron(IV) Nitrides.

    Science.gov (United States)

    Muñoz, Salvador B; Lee, Wei-Tsung; Dickie, Diane A; Scepaniak, Jeremiah J; Subedi, Deepak; Pink, Maren; Johnson, Michael D; Smith, Jeremy M

    2015-09-01

    Thermolysis of the iron(IV) nitride complex [PhB(tBuIm)3Fe≡N] with styrene leads to formation of the high-spin iron(II) aziridino complex [PhB(tBuIm)3Fe-N(CH2CHPh)]. Similar aziridination occurs with both electron-rich and electron-poor styrenes, while bulky styrenes hinder the reaction. The aziridino complex [PhB(tBuIm)3Fe-N(CH2CHPh)] acts as a nitride synthon, reacting with electron-poor styrenes to generate their corresponding aziridino complexes, that is, aziridine cross-metathesis. Reaction of [PhB(tBuIm)3Fe-N(CH2CHPh)] with Me3SiCl releases the N-functionalized aziridine Me3SiN(CH2CHPh) while simultaneously generating [PhB(tBuIm)3FeCl]. This closes a synthetic cycle for styrene azirdination by a nitride complex. While the less hindered iron(IV) nitride complex [PhB(MesIm)3Fe≡N] reacts with styrenes below room temperature, only bulky styrenes lead to tractable aziridino products. PMID:26179563

  2. Local residual stress measurements on nitride layers

    NARCIS (Netherlands)

    Mansilla, C.; Ocelik, V.; De Hosson, J. Th. M.

    2015-01-01

    In this work, local stresses in different nitrided maraging steel samples of high practical interest for industrial applications were studied through the so-called micro-slit milling method using a focused ion beam. The nitrogen concentration profiles were acquired by glow discharge optical emission

  3. Ammonothermal Growth of Gallium Nitride

    Science.gov (United States)

    Pimputkar, Siddha

    Bulk, single crystal Gallium Nitride (GaN) crystals are essential for enabling high performance electronic and optoelectronic devices by providing arbitrarily oriented, high quality, large, single crystal GaN substrates. Methods of producing single crystals of sufficient size and quality at a rate that would enable successful commercialization has been a major focus for research groups and companies worldwide. Recent advances have demonstrated remarkable improvements, though high cost and lack of high volume production remain key challenges. Major investments in bulk GaN growth were made at UCSB with particular focus on the ammonothermal method. The existing lab was upgraded and a new facility was designed and built with improved experimental setups for ammonothermal growth of GaN. The facilities can simultaneously operate up to 15 reactors of differing designs and capabilities with the ability to grow crystals up to 2 inches in diameter. A novel in-situ technique was devised to investigate the growth chemistry which occurs at typical operating conditions of 3,000 atm and 600 °C. Improvements in ammonothermal GaN include improved growth rates for c-plane by a factor of four to 344 μm/day with an overall record growth rate of 544 μm/day achieved for the (112¯2) plane. Crystal qualities comparable to that of the seed crystal were achieved. Impurity concentrations for transition metals were consistently reduced by a factor of 100 to concentrations below 1017 atoms/cm3. Optical transparency was improved by significantly reducing the yellow coloration typically seen for ammonothermal GaN. Single crystal GaN was successfully grown on large seeds and a 1 inch x ½ inch x ½ inch GaN crystal was demonstrated. To better understand the growth chemistry, models were created for the decomposition of ammonia under growth conditions, with initial experiments performed using the designed in-situ setup to verify the model's accuracy. To investigate the surface morphology and

  4. Anti corrosion layer for stainless steel in molten carbonate fuel cell - comprises phase vapour deposition of titanium nitride, aluminium nitride or chromium nitride layer then oxidising layer in molten carbonate electrolyte

    DEFF Research Database (Denmark)

    2000-01-01

    Forming an anticorrosion protective layer on a stainless steel surface used in a molten carbonate fuel cell (MCFC) - comprises the phase vapour deposition (PVD) of a layer comprising at least one of titanium nitride, aluminium nitride or chromium nitride and then forming a protective layer in situ...... by replacement of the nitride ions with oxide ions in the molten carbonate electrolyte....

  5. Metal surface nitriding by laser induced plasma

    Science.gov (United States)

    Thomann, A. L.; Boulmer-Leborgne, C.; Andreazza-Vignolle, C.; Andreazza, P.; Hermann, J.; Blondiaux, G.

    1996-10-01

    We study a nitriding technique of metals by means of laser induced plasma. The synthesized layers are composed of a nitrogen concentration gradient over several μm depth, and are expected to be useful for tribological applications with no adhesion problem. The nitriding method is tested on the synthesis of titanium nitride which is a well-known compound, obtained at present by many deposition and diffusion techniques. In the method of interest, a laser beam is focused on a titanium target in a nitrogen atmosphere, leading to the creation of a plasma over the metal surface. In order to understand the layer formation, it is necessary to characterize the plasma as well as the surface that it has been in contact with. Progressive nitrogen incorporation in the titanium lattice and TiN synthesis are studied by characterizing samples prepared with increasing laser shot number (100-4000). The role of the laser wavelength is also inspected by comparing layers obtained with two kinds of pulsed lasers: a transversal-excited-atmospheric-pressure-CO2 laser (λ=10.6 μm) and a XeCl excimer laser (λ=308 nm). Simulations of the target temperature rise under laser irradiation are performed, which evidence differences in the initial laser/material interaction (material heated thickness, heating time duration, etc.) depending on the laser features (wavelength and pulse time duration). Results from plasma characterization also point out that the plasma composition and propagation mode depend on the laser wavelength. Correlation of these results with those obtained from layer analyses shows at first the important role played by the plasma in the nitrogen incorporation. Its presence is necessary and allows N2 dissociation and a better energy coupling with the target. Second, it appears that the nitrogen diffusion governs the nitriding process. The study of the metal nitriding efficiency, depending on the laser used, allows us to explain the differences observed in the layer features

  6. Nitriding of Co–Cr–Mo alloy in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Ning, E-mail: ningtang@imr.tohoku.ac.jp; Li, Yunping, E-mail: lyping@imr.tohoku.ac.jp; Koizumi, Yuichiro; Chiba, Akihiko, E-mail: a.chiba@imr.tohoku.ac.jp

    2014-06-01

    Using the results of a thermodynamic analysis, a Co–Cr–Mo alloy was successfully nitrided in nitrogen at temperatures of 1073–1473 K. The near-surface microstructure of the treated Co–Cr–Mo alloy was characterized using X-ray diffraction, field-emission scanning electron microscopy, electron probe micro-analyzer, and transmission electron microscopy equipped with energy-dispersive X-ray spectroscopy. The results indicated that the highest nitriding efficiency was achieved at the treatment temperature of 1273 K, with the size and coverage of the nitride particles on sample's surface increasing with an increase in the treatment duration. After nitriding at 1273 K for 2 h, numerous nitride particles, consisting of an outer Cr{sub 2}N layer and an inner π phase layer, were formed on top of the nitrogen-containing γ phase, and some π phase also precipitated in the alloy matrix at the sub-surface level. - Highlights: • A Co–Cr–Mo alloy was successfully nitrided in nitrogen at 1073–1473 K. • The highest nitriding efficiency of the Co–Cr–Mo alloy was achieved at 1273 K. • Numerous nitride particles formed on sample's surface during nitriding at 1273 K. • The nitride particles consist of an outer Cr{sub 2}N layer and an inner π phase layer.

  7. Narrow spectral width laser diode for metastable argon atoms pumping

    Science.gov (United States)

    Gao, Jun; Li, Bin; Wang, Xinbing; Zuo, Duluo

    2016-03-01

    Diode laser pump source with narrow emitting spectrum for optically pumped metastable rare gas laser (OPRGL) of argon was achieved by employing a complex external cavity coupled with volume Bragg grating (VBG). A commercially available c-mount laser diode with rated power of 6 W was used and studied in both the free running mode and VBG external cavity. The maximum output power of 3.9 W with FWHM less than 25 pm and peak wavelength locked around 811.53 nm was obtained from the VBG external cavity laser diode. Precise control of VBG temperature enabled fine tuning of the emission wavelength over a range of 450 pm. Future researches on OPRGL of argon will benefit from it.

  8. Evaporation and condensation at a liquid surface. I. Argon

    Science.gov (United States)

    Yasuoka, Kenji; Matsumoto, Mitsuhiro; Kataoka, Yosuke

    1994-11-01

    Molecular dynamics computer simulations were carried out to investigate the dynamics of evaporation and condensation for argon at the temperature of 80 and 100 K. From the decrease of the survival probability of vapor molecules, the ratio of self reflection to collision is estimated to be 12%-15%, only weakly dependent on the temperature. This suggests that argon vapor molecules are in the condition of almost complete capture, and the condensation is considered to be a barrierless process. The total ratio of reflection which is evaluated with the flux correlation of condensation and evaporation is 20% at both temperature. The difference between these two ratios of reflection is ascribed to a phenomenon that vapor molecules colliding with the surface drive out other liquid molecules. This molecule exchange at the surface is as important as the self-reflection, and the conventional picture of condensation as a unimolecular chemical reaction is not appropriate.

  9. The Erosion of Frozen Argon by Swift Helium Ions

    DEFF Research Database (Denmark)

    Besenbacher, F.; Bøttiger, Jørgen; Graversen, O.;

    1981-01-01

    The temperature, energy, and thickness dependence of the erosion rates of frozen argon films when irradiated with 0.1–3 MeV helium ions have been measured. The erosion yields Y are much too high to be explained by the concentional collisional cascade-sputtering theory and are furthermore unequivo......The temperature, energy, and thickness dependence of the erosion rates of frozen argon films when irradiated with 0.1–3 MeV helium ions have been measured. The erosion yields Y are much too high to be explained by the concentional collisional cascade-sputtering theory and are furthermore...... unequivocally associated with electronic processes generated by the bombarding particle. In the present energy region, it is found that Y scales approximately as the electronic stopping power squared, depends on the charge state of the incoming helium ions, and perhaps more important, is independent...

  10. Demonstration of a Lightguide Detector for Liquid Argon TPCs

    CERN Document Server

    Bugel, L; Ignarra, C; Jones, B J P; Katori, T; Smidt, T; Tanaka, H -K

    2011-01-01

    We report demonstration of light detection in liquid argon using an acrylic lightguide detector system. This opens the opportunity for development of an inexpensive, large-area light collection system for large liquid argon time projection chambers. The guides are constructed of acrylic, with TPB embedded in a surface coating with a matching index of refraction. We study the response to early scintillation light produced by a 5.3 MeV alpha. We measure coating responses from 7 to 8 PE on average, compared to an ideal expectation of 10 PE on average. We estimate the attenuation length of light along the lightguide bar to be greater than 0.5 m. The coating response and the attenuation length can be improved; we show, however, that these results are already sufficient for triggering in a large detector.

  11. Trimming a Metallic Biliary Stent Using an Argon Plasma Coagulator

    International Nuclear Information System (INIS)

    Background. Distal migration is one of the common complications after insertion of a covered metallic stent. Stent repositioning or removal is not always possible in every patient. Therefore, trimming using an argon plasma coagulator (APC) may be a good alternative method to solve this problem. Methods. Metallic stent trimming by APC was performed in 2 patients with biliary Wallstent migration and in another patient with esophageal Ultraflex stent migration. The power setting was 60-100 watts with an argon flow of 0.8 l/min. Observations. The procedure was successfully performed and all distal parts of the stents were removed. No significant collateral damage to the nearby mucosa was observed. Conclusions. In a patient with a distally migrated metallic stent, trimming of the stent is possible by means of an APC. This new method may be applicable to other sites of metallic stent migration

  12. Readiness of the ATLAS Liquid Argon Calorimeter for LHC Collisions

    CERN Document Server

    Aad, G; Abdallah, J; Abdelalim, A A; Abdesselam, A; Abdinov, O; Abi, B; Abolins, M; Abramowicz, H; Abreu, H; Acharya, B S; Adams, D L; Addy, T N; Adelman, J; Adorisio, C; Adragna, P; Adye, T; Aefsky, S; Aguilar-Saavedra, J A; Aharrouche, M; Ahlen, S P; Ahles, F; Ahmad, A; Ahmed, H; Ahsan, M; Aielli, G; Akdogan, T; Åkesson, T P A; Akimoto, G; Akimov, A V; Aktas, A; Alam, M S; Alam, M A; Albert, J; Albrand, S; Aleksa, M; Aleksandrov, I N; Alessandria, F; Alexa, C; Alexander, G; Alexandre, G; Alexopoulos, T; Alhroob, M; Aliev, M; Alimonti, G; Alison, J; Aliyev, M; Allport, P P; Allwood-Spiers, S E; Almond, J; Aloisio, A; Alon, R; Alonso, A; Alviggi, M G; Amako, K; Amelung, C; Ammosov, V V; Amorim, A; Amorós, G; Amram, N; Anastopoulos, C; Andeen, T; Anders, C F; Anderson, K J; Andreazza, A; Andrei, V; Anduaga, X S; Angerami, A; Anghinolfi, F; Anjos, N; Antonaki, A; Antonelli, M; Antonelli, S; Antunovic, B; Anulli, F; Aoun, S; Arabidze, G; Aracena, I; Arai, Y; Arce, A T H; Archambault, J P; Arfaoui, S; Arguin, J-F; Argyropoulos, T; Arik, E; Arik, M; Armbruster, A J; Arnaez, O; Arnault, C; Artamonov, A; Arutinov, D; Asai, M; Asai, S; Asfandiyarov, R; Ask, S; Åsman, B; Asner, D; Asquith, L; Assamagan, K; Astbury, A; Astvatsatourov, A; Atoian, G; Auerbach, B; Auge, E; Augsten, K; Aurousseau, M; Austin, N; Avolio, G; Avramidou, R; Axen, D; Ay, C; Azuelos, G; Azuma, Y; Baak, M A; Baccaglioni, G; Bacci, C; Bach, A; Bachacou, H; Bachas, K; Backes, M; Badescu, E; Bagnaia, P; Bai, Y; Bailey, D C; Bain, T; Baines, J T; Baker, O K; Baker, M D; Baltasar Dos Santos Pedrosa, F; Banas, E; Banerjee, P; Banerjee, S; Banfi, D; Bangert, A; Bansal, V; Baranov, S P; Baranov, S; Barashkou, A; Barber, T; Barberio, E L; Barberis, D; Barbero, M; Bardin, D Y; Barillari, T; Barisonzi, M; Barklow, T; Barlow, N; Barnett, B M; Barnett, R M; Baron, S; Baroncelli, A; Barr, A J; Barreiro, F; BarreiroGuimarães da Costa, J; Barrillon, P; Barros, N; Bartoldus, R; Bartsch, D; Bastos, J; Bates, R L; Bathe, S; Batkova, L; Batley, J R; Battaglia, A; Battistin, M; Bauer, F; Bawa, H S; Bazalova, M; Beare, B; Beau, T; Beauchemin, P H; Beccherle, R; Becerici, N; Bechtle, P; Beck, G A; Beck, H P; Beckingham, M; Becks, K H; Bedajanek, I; Beddall, A J; Beddall, A; Bednár, P; Bednyakov, V A; Bee, C; Begel, M; Behar Harpaz, S; Behera, P K; Beimforde, M; Belanger-Champagne, C; Bell, P J; Bell, W H; Bella, G; Bellagamba, L; Bellina, F; Bellomo, M; Belloni, A; Belotskiy, K; Beltramello, O; Ben Ami, S; Benary, O; Benchekroun, D; Bendel, M; Benedict, B H; Benekos, N; Benhammou, Y; Benincasa, G P; Benjamin, D P; Benoit, M; Bensinger, J R; Benslama, K; Bentvelsen, S; Beretta, M; Berge, D; Bergeaas Kuutmann, E; Berger, N; Berghaus, F; Berglund, E; Beringer, J; Bernardet, K; Bernat, P; Bernhard, R; Bernius, C; Berry, T; Bertin, A; Besson, N; Bethke, S; Bianchi, R M; Bianco, M; Biebel, O; Biesiada, J; Biglietti, M; Bilokon, H; Bindi, M; Binet, S; Bingul, A; Bini, C; Biscarat, C; Bitenc, U; Black, K M; Blair, R E; Blanchard, J-B; Blanchot, G; Blocker, C; Blocki, J; Blondel, A; Blum, W; Blumenschein, U; Bobbink, G J; Bocci, A; Boehler, M; Boek, J; Boelaert, N; Böser, S; Bogaerts, J A; Bogouch, A; Bohm, C; Bohm, J; Boisvert, V; Bold, T; Boldea, V; Boldyrev, A; Bondarenko, V G; Bondioli, M; Boonekamp, M; Booth, J R A; Bordoni, S; Borer, C; Borisov, A; Borissov, G; Borjanovic, I; Borroni, S; Bos, K; Boscherini, D; Bosman, M; Bosteels, M; Boterenbrood, H; Bouchami, J; Boudreau, J; Bouhova-Thacker, E V; Boulahouache, C; Bourdarios, C; Boyd, J; Boyko, I R; Bozovic-Jelisavcic, I; Bracinik, J; Braem, A; Branchini, P; Brandenburg, G W; Brandt, A; Brandt, G; Brandt, O; Bratzler, U; Brau, B; Brau, J E; Braun, H M; Brelier, B; Bremer, J; Brenner, R; Bressler, S; Breton, D; Brett, N D; Britton, D; Brochu, F M; Brock, I; Brock, R; Brodbeck, T J; Brodet, E; Broggi, F; Bromberg, C; Brooijmans, G; Brooks, W K; Brown, G; Brubaker, E; Bruckman de Renstrom, P A; Bruncko, D; Bruneliere, R; Brunet, S; Bruni, A; Bruni, G; Bruschi, M; Buanes, T; Bucci, F; Buchanan, J; Buchholz, P; Buckley, A G; Budagov, I A; Budick, B; Büscher, V; Bugge, L; Bulekov, O; Bunse, M; Buran, T; Burckhart, H; Burdin, S; Burgess, T; Burke, S; Busato, E; Bussey, P; Buszello, C P; Butin, F; Butler, B; Butler, J M; Buttar, C M; Butterworth, J M; Byatt, T; Caballero, J; Cabrera Urbán, S; Caforio, D; Cakir, O; Calafiura, P; Calderini, G; Calfayan, P; Calkins, R; Caloba, L P; Caloi, R; Calvet, D; Camarri, P; Cambiaghi, M; Cameron, D; Campabadal-Segura, F; Campana, S; Campanelli, M; Canale, V; Canelli, F; Canepa, A; Cantero, J; Capasso, L; Capeans-Garrido, M D M; Caprini, I; Caprini, M; Capua, M; Caputo, R; Caracinha, D; Caramarcu, C; Cardarelli, R; Carli, T; Carlino, G; Carminati, L; Caron, B; Caron, S; Carrillo Montoya, G D; Carron Montero, S; Carter, A A; Carter, J R; Carvalho, J; Casadei, D; Casado, M P; Cascella, M; Caso, C; Castaneda Hernadez, A M; Castaneda-Miranda, E; Castillo Gimenez, V; Castro, N; Cataldi, G; Catinaccio, A; Catmore, J R; Cattai, A; Cattani, G; Caughron, S; Cauz, D; Cavalleri, P; Cavalli, D; Cavalli-Sforza, M; Cavasinni, V; Ceradini, F; Cerqueira, A S; Cerri, A; Cerrito, L; Cerutti, F; Cetin, S A; Cevenini, F; Chafaq, A; Chakraborty, D; Chan, K; Chapman, J D; Chapman, J W; Chareyre, E; Charlton, D G; Chavda, V; Cheatham, S; Chekanov, S; Chekulaev, S V; Chelkov, G A; Chen, H; Chen, S; Chen, T; Chen, X; Cheng, S; Cheplakov, A; Chepurnov, V F; Cherkaoui El Moursli, R; Tcherniatine, V; Chesneanu, D; Cheu, E; Cheung, S L; Chevalier, L; Chevallier, F; Chiarella, V; Chiefari, G; Chikovani, L; Childers, J T; Chilingarov, A; Chiodini, G; Chizhov, M; Choudalakis, G; Chouridou, S; Chren, D; Christidi, I A; Christov, A; Chromek-Burckhart, D; Chu, M L; Chudoba, J; Ciapetti, G; Ciftci, A K; Ciftci, R; Cinca, D; Cindro, V; Ciobotaru, M D; Ciocca, C; Ciocio, A; Cirilli, M; Citterio, M; Clark, A; Cleland, W; Clemens, J C; Clement, B; Clement, C; Clements, D; Coadou, Y; Cobal, M; Coccaro, A; Cochran, J; Coelli, S; Coggeshall, J; Cogneras, E; Cojocaru, C D; Colas, J; Cole, B; Colijn, A P; Collard, C; Collins, N J; Collins-Tooth, C; Collot, J; Colon, G; Coluccia, R; Conde Muiño, P; Coniavitis, E; Consonni, M; Constantinescu, S; Conta, C; Conventi, F; Cook, J; Cooke, M; Cooper, B D; Cooper-Sarkar, A M; Cooper-Smith, N J; Copic, K; Cornelissen, T; Corradi, M; Corriveau, F; Corso-Radu, A; Cortes-Gonzalez, A; Cortiana, G; Costa, G; Costa, M J; Costanzo, D; Costin, T; Côté, D; Coura Torres, R; Courneyea, L; Cowan, G; Cowden, C; Cox, B E; Cranmer, K; Cranshaw, J; Cristinziani, M; Crosetti, G; Crupi, R; Crépé-Renaudin, S; Cuenca Almenar, C; Cuhadar Donszelmann, T; Curatolo, M; Curtis, C J; Cwetanski, P; Czyczula, Z; D'Auria, S; D'Onofrio, M; D'Orazio, A; Da Silva, P V M; Da Via, C; Dabrowski, W; Dai, T; Dallapiccola, C; Dallison, S J; Daly, C H; Dam, M; Danielsson, H O; Dannheim, D; Dao, V; Darbo, G; Darlea, G L; Davey, W; Davidek, T; Davidson, N; Davidson, R; Davison, A R; Dawson, I; Dawson, J W; Daya, R K; De, K; de Asmundis, R; De Castro, S; De Castro Faria Salgado, P E; De Cecco, S; de Graat, J; De Groot, N; de Jong, P; De La Cruz Burelo, E; De La Taille, C; De Mora, L; De Oliveira Branco, M; De Pedis, D; De Salvo, A; De Sanctis, U; De Santo, A; De Vivie De Regie, J B; De Zorzi, G; Dean, S; Deberg, H; Dedes, G; Dedovich, D V; Defay, P O; Degenhardt, J; Dehchar, M; Del Papa, C; Del Peso, J; Del Prete, T; Dell'Acqua, A; Dell'Asta, L; Della Pietra, M; della Volpe, D; Delmastro, M; Delruelle, N; Delsart, P A; Deluca, C; Demers, S; Demichev, M; Demirkoz, B; Deng, J; Deng, W; Denisov, S P; Dennis, C; Derkaoui, J E; Derue, F; Dervan, P; Desch, K; Deviveiros, P O; Dewhurst, A; DeWilde, B; Dhaliwal, S; Dhullipudi, R; Di Ciaccio, A; Di Ciaccio, L; Di Domenico, A; Di Girolamo, A; Di Girolamo, B; Di Luise, S; Di Mattia, A; Di Nardo, R; Di Simone, A; Di Sipio, R; Diaz, M A; Diblen, F; Diehl, E B; Dietrich, J; Diglio, S; Dindar Yagci, K; Dingfelder, D J; Dionisi, C; Dita, P; Dita, S; Dittus, F; Djama, F; Djilkibaev, R; Djobava, T; do Vale, M A B; Do Valle Wemans, A; Dobbs, M; Dobos, D; Dobson, E; Dobson, M; Dodd, J; Dogan, O B; Doherty, T; Doi, Y; Dolejsi, J; Dolenc, I; Dolezal, Z; Dolgoshein, B A; Dohmae, T; Donega, M; Donini, J; Dopke, J; Doria, A; Dos Anjos, A; Dotti, A; Dova, M T; Doxiadis, A; Doyle, A T; Drasal, Z; Driouichi, C; Dris, M; Dubbert, J; Duchovni, E; Duckeck, G; Dudarev, A; Dudziak, F; Dührssen , M; Duflot, L; Dufour, M-A; Dunford, M; Duperrin, A; Duran-Yildiz, H; Dushkin, A; Duxfield, R; Dwuznik, M; Düren, M; Ebenstein, W L; Ebke, J; Eckert, S; Eckweiler, S; Edmonds, K; Edwards, C A; Eerola, P; Egorov, K; Ehrenfeld, W; Ehrich, T; Eifert, T; Eigen, G; Einsweiler, K; Eisenhandler, E; Ekelof, T; El Kacimi, M; Ellert, M; Elles, S; Ellinghaus, F; Ellis, K; Ellis, N; Elmsheuser, J; Elsing, M; Ely, R; Emeliyanov, D; Engelmann, R; Engl, A; Epp, B; Eppig, A; Epshteyn, V S; Ereditato, A; Eriksson, D; Ermoline, I; Ernst, J; Ernst, M; Ernwein, J; Errede, D; Errede, S; Ertel, E; Escalier, M; Escobar, C; Espinal Curull, X; Esposito, B; Etienne, F; Etienvre, A I; Etzion, E; Evans, H; Fabbri, L; Fabre, C; Faccioli, P; Facius, K; Fakhrutdinov, R M; Falciano, S; Falou, A C; Fang, Y; Fanti, M; Farbin, A; Farilla, A; Farley, J; Farooque, T; Farrington, S M; Farthouat, P; Fassi, F; Fassnacht, P; Fassouliotis, D; Fatholahzadeh, B; Fayard, L; Fayette, F; Febbraro, R; Federic, P; Fedin, O L; Fedorko, I; Fedorko, W; Feligioni, L; Felzmann, C U; Feng, C; Feng, E J; Fenyuk, A B; Ferencei, J; Ferland, J; Fernandes, B; Fernando, W; Ferrag, S; Ferrando, J; Ferrari, A; Ferrari, P; Ferrari, R; Ferrer, A; Ferrer, M L; Ferrere, D; Ferretti, C; Fiascaris, M; Fiedler, F; Filipcic, A; Filippas, A; Filthaut, F; Fincke-Keeler, M; Fiolhais, M C N; Fiorini, L; Firan, A; Fischer, G; Fisher, M J; Flechl, M; Fleck, I; Fleckner, J; Fleischmann, P; Fleischmann, S; Flick, T; Flores-Castillo, L R; Flowerdew, M J; Föhlisch, F; Fokitis, M; Fonseca Martin, T; Forbush, D A; Formica, A; Forti, A; Fortin, D; Foster, J M; Fournier, D; Foussat, A; Fowler, A J; Fowler, K; Fox, H; Francavilla, P; Franchino, S; Francis, D; Franklin, M; Franz, S; Fraternali, M; Fratina, S; Freestone, J; French, S T; Froeschl, R; Froidevaux, D; Frost, J A; Fukunaga, C; Fullana Torregrosa, E; Fuster, J; Gabaldon, C; Gabizon, O; Gadfort, T; Gadomski, S; Gagliardi, G; Gagnon, P; Galea, C; Gallas, E J; Gallas, M V; Gallop, B J; Gallus, P; Galyaev, E; Gan, K K; Gao, Y S; Gaponenko, A; Garcia-Sciveres, M; Garcí­a, C; Garcí­a Navarro, J E; Gardner, R W; Garelli, N; Garitaonandia, H; Garonne, V; Gatti, C; Gaudio, G; Gaumer, O; Gauzzi, P; Gavrilenko, I L; Gay, C; Gaycken, G; Gayde, J-C; Gazis, E N; Ge, P; Gee, C N P; Geich-Gimbel, Ch; Gellerstedt, K; Gemme, C; Genest, M H; Gentile, S; Georgatos, F; George, S; Gerlach, P; Gershon, A; Geweniger, C; Ghazlane, H; Ghez, P; Ghodbane, N; Giacobbe, B; Giagu, S; Giakoumopoulou, V; Giangiobbe, V; Gianotti, F; Gibbard, B; Gibson, A; Gibson, S M; Gilbert, L M; Gilchriese, M; Gilewsky, V; Gillberg, D; Gillman, A R; Gingrich, D M; Ginzburg, J; Giokaris, N; Giordani, M P; Giordano, R; Giovannini, P; Giraud, P F; Girtler, P; Giugni, D; Giusti, P; Gjelsten, B K; Gladilin, L K; Glasman, C; Glazov, A; Glitza, K W; Glonti, G L; Godfrey, J; Godlewski, J; Goebel, M; Göpfert, T; Goeringer, C; Gössling, C; Göttfert, T; Goggi, V; Goldfarb, S; Goldin, D; Golling, T; Gollub, N P; Gomes, A; Gomez Fajardo, L S; Gonçalo, R; Gonella, L; Gong, C; González de la Hoz, S; Gonzalez Silva, M L; Gonzalez-Sevilla, S; Goodson, J J; Goossens, L; Gorbounov, P A; Gordon, H A; Gorelov, I; Gorfine, G; Gorini, B; Gorini, E; Gorisek, A; Gornicki, E; Goryachev, S V; Goryachev, V N; Gosdzik, B; Gosselink, M; Gostkin, M I; Gough Eschrich, I; Gouighri, M; Goujdami, D; Goulette, M P; Goussiou, A G; Goy, C; Grabowska-Bold, I; Grafström, P; Grahn, K-J; Granado Cardoso, L; Grancagnolo, F; Grancagnolo, S; Grassi, V; Gratchev, V; Grau, N; Gray, H M; Gray, J A; Graziani, E; Green, B; Greenshaw, T; Greenwood, Z D; Gregor, I M; Grenier, P; Griesmayer, E; Griffiths, J; Grigalashvili, N; Grillo, A A; Grimm, K; Grinstein, S; Grishkevich, Y V; Groer, L S; Grognuz, J; Groh, M; Groll, M; Gross, E; Grosse-Knetter, J; Groth-Jensen, J; Grybel, K; Guarino, V J; Guicheney, C; Guida, A; Guillemin, T; Guler, H; Gunther, J; Guo, B; Gupta, A; Gusakov, Y; Gutierrez, A; Gutierrez, P; Guttman, N; Gutzwiller, O; Guyot, C; Gwenlan, C; Gwilliam, C B; Haas, A; Haas, S; Haber, C; Hackenburg, R; Hadavand, H K; Hadley, D R; Haefner, P; Härtel, R; Hajduk, Z; Hakobyan, H; Haller, J; Hamacher, K; Hamilton, A; Hamilton, S; Han, H; Han, L; Hanagaki, K; Hance, M; Handel, C; Hanke, P; Hansen, J R; Hansen, J B; Hansen, J D; Hansen, P H; Hansl-Kozanecka, T; Hansson, P; Hara, K; Hare, G A; Harenberg, T; Harrington, R D; Harris, O B; Harris, O M; Harrison, K; Hartert, J; Hartjes, F; Haruyama, T; Harvey, A; Hasegawa, S; Hasegawa, Y; Hashemi, K; Hassani, S; Hatch, M; Haug, F; Haug, S; Hauschild, M; Hauser, R; Havranek, M; Hawkes, C M; Hawkings, R J; Hawkins, D; Hayakawa, T; Hayward, H S; Haywood, S J; He, M; Head, S J; Hedberg, V; Heelan, L; Heim, S; Heinemann, B; Heisterkamp, S; Helary, L; Heller, M; Hellman, S; Helsens, C; Hemperek, T; Henderson, R C W; Henke, M; Henrichs, A; Henriques-Correia, A M; Henrot-Versille, S; Hensel, C; Henß, T; Hershenhorn, A D; Herten, G; Hertenberger, R; Hervas, L; Hessey, N P; Hidvegi, A; Higón-Rodriguez, E; Hill, D; Hill, J C; Hiller, K H; Hillier, S J; Hinchliffe, I; Hirose, M; Hirsch, F; Hobbs, J; Hod, N; Hodgkinson, M C; Hodgson, P; Hoecker, A; Hoeferkamp, M R; Hoffman, J; Hoffmann, D; Hohlfeld, M; Holmgren, S O; Holy, T; Holzbauer, J L; Homma, Y; Homola, P; Horazdovsky, T; Hori, T; Horn, C; Horner, S; Horvat, S; Hostachy, J-Y; Hou, S; Houlden, M A; Hoummada, A; Howe, T; Hrivnac, J; Hryn'ova, T; Hsu, P J; Hsu, S-C; Huang, G S; Hubacek, Z; Hubaut, F; Huegging, F; Hughes, E W; Hughes, G; Hughes-Jones, R E; Hurst, P; Hurwitz, M; Husemann, U; Huseynov, N; Huston, J; Huth, J; Iacobucci, G; Iakovidis, G; Ibragimov, I; Iconomidou-Fayard, L; Idarraga, J; Iengo, P; Igonkina, O; Ikegami, Y; Ikeno, M; Ilchenko, Y; Iliadis, D; Ilyushenka, Y; Imori, M; Ince, T; Ioannou, P; Iodice, M; Irles-Quiles, A; Ishikawa, A; Ishino, M; Ishmukhametov, R; Isobe, T; Issakov, V; Issever, C; Istin, S; Itoh, Y; Ivashin, A V; Iwanski, W; Iwasaki, H; Izen, J M; Izzo, V; Jackson, J N; Jackson, P; Jaekel, M; Jahoda, M; Jain, V; Jakobs, K; Jakobsen, S; Jakubek, J; Jana, D; Jansen, E; Jantsch, A; Janus, M; Jared, R C; Jarlskog, G; Jarron, P; Jeanty, L; Jelen, K; Jen-La Plante, I; Jenni, P; Jez, P; Jézéquel, S; Ji, W; Jia, J; Jiang, Y; Jimenez Belenguer, M; Jin, G; Jin, S; Jinnouchi, O; Joffe, D; Johansen, M; Johansson, K E; Johansson, P; Johnert, S; Johns, K A; Jon-And, K; Jones, G; Jones, R W L; Jones, T W; Jones, T J; Jonsson, O; Joos, D; Joram, C; Jorge, P M; Juranek, V; Jussel, P; Kabachenko, V V; Kabana, S; Kaci, M; Kaczmarska, A; Kado, M; Kagan, H; Kagan, M; Kaiser, S; Kajomovitz, E; Kalinovskaya, L V; Kalinowski, A; Kama, S; Kanaya, N; Kaneda, M; Kantserov, V A; Kanzaki, J; Kaplan, B; Kapliy, A; Kaplon, J; Karagounis, M; Karagoz Unel, M; Kartvelishvili, V; Karyukhin, A N; Kashif, L; Kasmi, A; Kass, R D; Kastanas, A; Kastoryano, M; Kataoka, M; Kataoka, Y; Katsoufis, E; Katzy, J; Kaushik, V; Kawagoe, K; Kawamoto, T; Kawamura, G; Kayl, M S; Kayumov, F; Kazanin, V A; Kazarinov, M Y; Kazi, S I; Keates, J R; Keeler, R; Keener, P T; Kehoe, R; Keil, M; Kekelidze, G D; Kelly, M; Kennedy, J; Kenyon, M; Kepka, O; Kerschen, N; Kersevan, B P; Kersten, S; Kessoku, K; Khakzad, M; Khalil-zada, F; Khandanyan, H; Khanov, A; Kharchenko, D; Khodinov, A; Kholodenko, A G; Khomich, A; Khoriauli, G; Khovanskiy, N; Khovanskiy, V; Khramov, E; Khubua, J; Kilvington, G; Kim, H; Kim, M S; Kim, P C; Kim, S H; Kind, O; Kind, P; King, B T; Kirk, J; Kirsch, G P; Kirsch, L E; Kiryunin, A E; Kisielewska, D; Kittelmann, T; Kiyamura, H; Kladiva, E; Klein, M; Klein, U; Kleinknecht, K; Klemetti, M; Klier, A; Klimentov, A; Klingenberg, R; Klinkby, E B; Klioutchnikova, T; Klok, P F; Klous, S; Kluge, E-E; Kluge, T; Kluit, P; Klute, M; Kluth, S; Knecht, N S; Kneringer, E; Ko, B R; Kobayashi, T; Kobel, M; Koblitz, B; Kocian, M; Kocnar, A; Kodys, P; Köneke, K; König, A C; Köpke, L; Koetsveld, F; Koevesarki, P; Koffas, T; Koffeman, E; Kohn, F; Kohout, Z; Kohriki, T; Kokott, T; Kolanoski, H; Kolesnikov, V; Koletsou, I; Koll, J; Kollar, D; Kolos, S; Kolya, S D; Komar, A A; Komaragiri, J R; Kondo, T; Kono, T; Kononov, A I; Konoplich, R; Konovalov, S P; Konstantinidis, N; Koperny, S; Korcyl, K; Kordas, K; Koreshev, V; Korn, A; Korolkov, I; Korolkova, E V; Korotkov, V A; Kortner, O; Kostka, P; Kostyukhin, V V; Kotamäki, M J; Kotov, S; Kotov, V M; Kotov, K Y; Koupilova, Z; Kourkoumelis, C; Koutsman, A; Kowalewski, R; Kowalski, H; Kowalski, T Z; Kozanecki, W; Kozhin, A S; Kral, V; Kramarenko, V A; Kramberger, G; Krasny, M W; Krasznahorkay, A; Kreisel, A; Krejci, F; Krepouri, A; Kretzschmar, J; Krieger, P; Krobath, G; Kroeninger, K; Kroha, H; Kroll, J; Kroseberg, J; Krstic, J; Kruchonak, U; Krüger, H; Krumshteyn, Z V; Kubota, T; Kuehn, S; Kugel, A; Kuhl, T; Kuhn, D; Kukhtin, V; Kulchitsky, Y; Kuleshov, S; Kummer, C; Kuna, M; Kupco, A; Kurashige, H; Kurata, M; Kurchaninov, L L; Kurochkin, Y A; Kus, V; Kuykendall, W; Kuznetsova, E; Kvasnicka, O; Kwee, R; La Rosa, M; La Rotonda, L; Labarga, L; Labbe, J; Lacasta, C; Lacava, F; Lacker, H; Lacour, D; Lacuesta, V R; Ladygin, E; Lafaye, R; Laforge, B; Lagouri, T; Lai, S; Lamanna, M; Lampen, C L; Lampl, W; Lancon, E; Landgraf, U; Landon, M P J; Lane, J L; Lankford, A J; Lanni, F; Lantzsch, K; Lanza, A; Laplace, S; Lapoire, C; Laporte, J F; Lari, T; Larionov, A V; Larner, A; Lasseur, C; Lassnig, M; Laurelli, P; Lavrijsen, W; Laycock, P; Lazarev, A B; Lazzaro, A; Le Dortz, O; Le Guirriec, E; Le Maner, C; Le Menedeu, E; Le Vine, M; Leahu, M; Lebedev, A; Lebel, C; LeCompte, T; Ledroit-Guillon, F; Lee, H; Lee, J S H; Lee, S C; Lefebvre, M; Legendre, M; LeGeyt, B C; Legger, F; Leggett, C; Lehmacher, M; Lehmann Miotto, G; Lei, X; Leitner, R; Lelas, D; Lellouch, D; Lellouch, J; Leltchouk, M; Lendermann, V; Leney, K J C; Lenz, T; Lenzen, G; Lenzi, B; Leonhardt, K; Leroy, C; Lessard, J-R; Lester, C G; Leung Fook Cheong, A; Levêque, J; Levin, D; Levinson, L J; Levitski, M S; Levonian, S; Lewandowska, M; Leyton, M; Li, H; Li, J; Li, S; Li, X; Liang, Z; Liang, Z; Liberti, B; Lichard, P; Lichtnecker, M; Lie, K; Liebig, W; Liko, D; Lilley, J N; Lim, H; Limosani, A; Limper, M; Lin, S C; Lindsay, S W; Linhart, V; Linnemann, J T; Liolios, A; Lipeles, E; Lipinsky, L; Lipniacka, A; Liss, T M; Lissauer, D; Litke, A M; Liu, C; Liu, D; Liu, H; Liu, J B; Liu, M; Liu, S; Liu, T; Liu, Y; Livan, M; Lleres, A; Lloyd, S L; Lobodzinska, E; Loch, P; Lockman, W S; Lockwitz, S; Loddenkoetter, T; Loebinger, F K; Loginov, A; Loh, C W; Lohse, T; Lohwasser, K; Lokajicek, M; Loken, J; Lopes, L; Lopez Mateos, D; Losada, M; Loscutoff, P; Losty, M J; Lou, X; Lounis, A; Loureiro, K F; Lovas, L; Love, J; Love, P; Lowe, A J; Lu, F; Lu, J; Lubatti, H J; Luci, C; Lucotte, A; Ludwig, A; Ludwig, D; Ludwig, I; Ludwig, J; Luehring, F; Luisa, L; Lumb, D; Luminari, L; Lund, E; Lund-Jensen, B; Lundberg, B; Lundberg, J; Lundquist, J; Lutz, G; Lynn, D; Lys, J; Lytken, E; Ma, H; Ma, L L; Maccarrone, G; Macchiolo, A; Macek, B; Machado Miguens, J; Mackeprang, R; Madaras, R J; Mader, W F; Maenner, R; Maeno, T; Mättig, P; Mättig, S; Magalhaes Martins, P J; Magradze, E; Magrath, C A; Mahalalel, Y; Mahboubi, K; Mahmood, A; Mahout, G; Maiani, C; Maidantchik, C; Maio, A; Majewski, S; Makida, Y; Makouski, M; Makovec, N; Malecki, Pa; Malecki, P; Maleev, V P; Malek, F; Mallik, U; Malon, D; Maltezos, S; Malyshev, V; Malyukov, S; Mambelli, M; Mameghani, R; Mamuzic, J; Manabe, A; Mandelli, L; Mandic, I; Mandrysch, R; Maneira, J; Mangeard, P S; Manjavidze, I D; Manousakis-Katsikakis, A; Mansoulie, B; Mapelli, A; Mapelli, L; March, L; Marchand, J F; Marchese, F; Marcisovsky, M; Marino, C P; Marques, C N; Marroquim, F; Marshall, R; Marshall, Z; Martens, F K; Marti i Garcia, S; Martin, A J; Martin, A J; Martin, B; Martin, B; Martin, F F; Martin, J P; Martin, T A; Martin dit Latour, B; Martinez, M; Martinez Outschoorn, V; Martini, A; Martynenko, V; Martyniuk, A C; Maruyama, T; Marzano, F; Marzin, A; Masetti, L; Mashimo, T; Mashinistov, R; Masik, J; Maslennikov, A L; Massaro, G; Massol, N; Mastroberardino, A; Masubuchi, T; Mathes, M; Matricon, P; Matsumoto, H; Matsunaga, H; Matsushita, T; Mattravers, C; Maxfield, S J; May, E N; Mayne, A; Mazini, R; Mazur, M; Mazzanti, M; Mazzanti, P; Mc Donald, J; Mc Kee, S P; McCarn, A; McCarthy, R L; McCubbin, N A; McFarlane, K W; McGlone, H; Mchedlidze, G; McLaren, R A; McMahon, S J; McMahon, T R; McPherson, R A; Meade, A; Mechnich, J; Mechtel, M; Medinnis, M; Meera-Lebbai, R; Meguro, T M; Mehdiyev, R; Mehlhase, S; Mehta, A; Meier, K; Meirose, B; Melamed-Katz, A; Mellado Garcia, B R; Meng, Z; Menke, S; Meoni, E; Merkl, D; Mermod, P; Merola, L; Meroni, C; Merritt, F S; Messina, A M; Messmer, I; Metcalfe, J; Mete, A S; Meyer, J-P; Meyer, J; Meyer, T C; Meyer, W T; Miao, J; Micu, L; Middleton, R P; Migas, S; Mijovic, L; Mikenberg, G; Mikuz, M; Miller, D W; Mills, W J; Mills, C M; Milov, A; Milstead, D A; Minaenko, A A; Miñano, M; Minashvili, I A; Mincer, A I; Mindur, B; Mineev, M; Mir, L M; Mirabelli, G; Misawa, S; Miscetti, S; Misiejuk, A; Mitrevski, J; Mitsou, V A; Miyagawa, P S; Mjörnmark, J U; Mladenov, D; Moa, T; Mockett, P; Moed, S; Moeller, V; Mönig, K; Möser, N; Mohn, B; Mohr, W; Mohrdieck-Möck, S; Moles-Valls, R; Molina-Perez, J; Moloney, G; Monk, J; Monnier, E; Montesano, S; Monticelli, F; Moore, R W; Mora-Herrera, C; Moraes, A; Morais, A; Morel, J; Morello, G; Moreno, D; Moreno Llácer, M; Morettini, P; Morii, M; Morley, A K; Mornacchi, G; Morozov, S V; Morris, J D; Moser, H G; Mosidze, M; Moss, J; Mount, R; Mountricha, E; Mouraviev, S V; Moyse, E J W; Mudrinic, M; Mueller, F; Mueller, J; Mueller, K; Müller, T A; Muenstermann, D; Muir, A; Murillo Garcia, R; Murray, W J; Mussche, I; Musto, E; Myagkov, A G; Myska, M; Nadal, J; Nagai, K; Nagano, K; Nagasaka, Y; Nairz, A M; Nakamura, K; Nakano, I; Nakatsuka, H; Nanava, G; Napier, A; Nash, M; Nation, N R; Nattermann, T; Naumann, T; Navarro, G; Nderitu, S K; Neal, H A; Nebot, E; Nechaeva, P; Negri, A; Negri, G; Nelson, A; Nelson, T K; Nemecek, S; Nemethy, P; Nepomuceno, A A; Nessi, M; Neubauer, M S; Neusiedl, A; Neves, R N; Nevski, P; Newcomer, F M; Nicholson, C; Nickerson, R B; Nicolaidou, R; Nicolas, L; Nicoletti, G; Niedercorn, F; Nielsen, J; Nikiforov, A; Nikolaev, K; Nikolic-Audit, I; Nikolopoulos, K; Nilsen, H; Nilsson, P; Nisati, A; Nishiyama, T; Nisius, R; Nodulman, L; Nomachi, M; Nomidis, I; Nomoto, H; Nordberg, M; Nordkvist, B; Notz, D; Novakova, J; Nozaki, M; Nozicka, M; Nugent, I M; Nuncio-Quiroz, A-E; Nunes Hanninger, G; Nunnemann, T; Nurse, E; O'Neil, D C; O'Shea, V; Oakham, F G; Oberlack, H; Ochi, A; Oda, S; Odaka, S; Odier, J; Odino, G A; Ogren, H; Oh, S H; Ohm, C C; Ohshima, T; Ohshita, H; Ohsugi, T; Okada, S; Okawa, H; Okumura, Y; Olcese, M; Olchevski, A G; Oliveira, M; Oliveira Damazio, D; Oliver, J; Oliver Garcia, E; Olivito, D; Olszewski, A; Olszowska, J; Omachi, C; Onofre, A; Onyisi, P U E; Oram, C J; Ordonez, G; Oreglia, M J; Oren, Y; Orestano, D; Orlov, I; Oropeza Barrera, C; Orr, R S; Ortega, E O; Osculati, B; Osuna, C; Otec, R; Ottersbach, J P; Ould-Saada, F; Ouraou, A; Ouyang, Q; Owen, M; Owen, S; Ozcan, V E; Ozone, K; Ozturk, N; Pacheco Pages, A; Padhi, S; Padilla Aranda, C; Paganis, E; Pahl, C; Paige, F; Pajchel, K; Pal, A; Palestini, S; Pallin, D; Palma, A; Palmer, J D; Pan, Y B; Panagiotopoulou, E; Panes, B; Panikashvili, N; Panitkin, S; Pantea, D; Panuskova, M; Paolone, V; Papadopoulou, Th D; Park, S J; Park, W; Parker, M A; Parker, S I; Parodi, F; Parsons, J A; Parzefall, U; Pasqualucci, E; Passardi, G; Passeri, A; Pastore, F; Pastore, Fr; Pásztor, G; Pataraia, S; Pater, J R; Patricelli, S; Patwa, A; Pauly, T; Peak, L S; Pecsy, M; Pedraza Morales, M I; Peleganchuk, S V; Peng, H; Penson, A; Penwell, J; Perantoni, M; Perez, K; Perez Codina, E; Pérez García-Estañ, M T; Perez Reale, V; Perini, L; Pernegger, H; Perrino, R; Perrodo, P; Persembe, S; Perus, P; Peshekhonov, V D; Petersen, B A; Petersen, J; Petersen, T C; Petit, E; Petridou, C; Petrolo, E; Petrucci, F; Petschull, D; Petteni, M; Pezoa, R; Pfeifer, B; Phan, A; Phillips, A W; Piacquadio, G; Piccinini, M; Piegaia, R; Pilcher, J E; Pilkington, A D; Pina, J; Pinamonti, M; Pinfold, J L; Ping, J; Pinto, B; Pirotte, O; Pizio, C; Placakyte, R; Plamondon, M; Plano, W G; Pleier, M-A; Poblaguev, A; Poddar, S; Podlyski, F; Poffenberger, P; Poggioli, L; Pohl, M; Polci, F; Polesello, G; Policicchio, A; Polini, A; Poll, J; Polychronakos, V; Pomarede, D M; Pomeroy, D; Pommès, K; Pontecorvo, L; Pope, B G; Popovic, D S; Poppleton, A; Popule, J; Portell Bueso, X; Porter, R; Pospelov, G E; Pospichal, P; Pospisil, S; Potekhin, M; Potrap, I N; Potter, C J; Potter, C T; Potter, K P; Poulard, G; Poveda, J; Prabhu, R; Pralavorio, P; Prasad, S; Pravahan, R; Preda, T; Pretzl, K; Pribyl, L; Price, D; Price, L E; Prichard, P M; Prieur, D; Primavera, M; Prokofiev, K; Prokoshin, F; Protopopescu, S; Proudfoot, J; Prudent, X; Przysiezniak, H; Psoroulas, S; Ptacek, E; Puigdengoles, C; Purdham, J; Purohit, M; Puzo, P; Pylypchenko, Y; Qi, M; Qian, J; Qian, W; Qian, Z; Qin, Z; Qing, D; Quadt, A; Quarrie, D R; Quayle, W B; Quinonez, F; Raas, M; Radeka, V; Radescu, V; Radics, B; Rador, T; Ragusa, F; Rahal, G; Rahimi, A M; Rahm, D; Rajagopalan, S; Rammes, M; Ratoff, P N; Rauscher, F; Rauter, E; Raymond, M; Read, A L; Rebuzzi, D M; Redelbach, A; Redlinger, G; Reece, R; Reeves, K; Reinherz-Aronis, E; Reinsch, A; Reisinger, I; Reljic, D; Rembser, C; Ren, Z L; Renkel, P; Rescia, S; Rescigno, M; Resconi, S; Resende, B; Reznicek, P; Rezvani, R; Richards, A; Richards, R A; Richter, D; Richter, R; Richter-Was, E; Ridel, M; Rieke, S; Rijpstra, M; Rijssenbeek, M; Rimoldi, A; Rinaldi, L; Rios, R R; Riu, I; Rivoltella, G; Rizatdinova, F; Rizvi, E R; Roa-Romero, D A; Robertson, S H; Robichaud-Veronneau, A; Robinson, D; Robinson, M; Robson, A; Rocha de Lima, J G; Roda, C; Rodriguez, D; Rodriguez Garcia, Y; Roe, S; Røhne, O; Rojo, V; Rolli, S; Romaniouk, A; Romanov, V M; Romeo, G; Romero-Maltrana, D; Roos, L; Ros, E; Rosati, S; Rosenbaum, G A; Rosenberg, E I; Rosselet, L; Rossi, L P; Rotaru, M; Rothberg, J; Rottländer, I; Rousseau, D; Royon, C R; Rozanov, A; Rozen, Y; Ruan, X; Ruckert, B; Ruckstuhl, N; Rud, V I; Rudolph, G; Rühr, F; Ruggieri, F; Ruiz-Martinez, A; Rumyantsev, L; Rusakovich, N A; Rutherfoord, J P; Ruwiedel, C; Ruzicka, P; Ryabov, Y F; Ryadovikov, V; Ryan, P; Rybkin, G; Rzaeva, S; Saavedra, A F; Sadrozinski, H F-W; Sadykov, R; Sakamoto, H; Salamanna, G; Salamon, A; Saleem, M; Salihagic, D; Salnikov, A; Salt, J; Salvachua-Ferrando, B M; Salvatore, D; Salvatore, F; Salvucci, A; Salzburger, A; Sampsonidis, D; Samset, B H; Sanchis Lozano, M A; Sandaker, H; Sander, H G; Sanders, M P; Sandhoff, M; Sandstroem, R; Sandvoss, S; Sankey, D P C; Sanny, B; Sansoni, A; Santamarina Rios, C; Santi, L; Santoni, C; Santonico, R; Santos, D; Santos, J; Saraiva, J G; Sarangi, T; Sarkisyan-Grinbaum, E; Sarri, F; Sasaki, O; Sasaki, T; Sasao, N; Satsounkevitch, I; Sauvage, G; Savard, P; Savine, A Y; Savinov, V; Sawyer, L; Saxon, D H; Says, L P; Sbarra, C; Sbrizzi, A; Scannicchio, D A; Schaarschmidt, J; Schacht, P; Schäfer, U; Schaetzel, S; Schaffer, A C; Schaile, D; Schamberger, R D; Schamov, A G; Schegelsky, V A; Scheirich, D; Schernau, M; Scherzer, M I; Schiavi, C; Schieck, J; Schioppa, M; Schlenker, S; Schlereth, J L; Schmid, P; Schmidt, M P; Schmieden, K; Schmitt, C; Schmitz, M; Schott, M; Schouten, D; Schovancova, J; Schram, M; Schreiner, A; Schroeder, C; Schroer, N; Schroers, M; Schuler, G; Schultes, J; Schultz-Coulon, H-C; Schumacher, J; Schumacher, M; Schumm, B A; Schune, Ph; Schwanenberger, C; Schwartzman, A; Schwemling, Ph; Schwienhorst, R; Schwierz, R; Schwindling, J; Scott, W G; Searcy, J; Sedykh, E; Segura, E; Seidel, S C; Seiden, A; Seifert, F; Seixas, J M; Sekhniaidze, G; Seliverstov, D M; Sellden, B; Seman, M; Semprini-Cesari, N; Serfon, C; Serin, L; Seuster, R; Severini, H; Sevior, M E; Sfyrla, A; Shamim, M; Shan, L Y; Shank, J T; Shao, Q T; Shapiro, M; Shatalov, P B; Shaver, L; Shaw, C; Shaw, K; Sherman, D; Sherwood, P; Shibata, A; Shimojima, M; Shin, T; Shmeleva, A; Shochet, M J; Shupe, M A; Sicho, P; Sidoti, A; Siebel, A; Siegert, F; Siegrist, J; Sijacki, Dj; Silbert, O; Silva, J; Silver, Y; Silverstein, D; Silverstein, S B; Simak, V; Simic, Lj; Simion, S; Simmons, B; Simonyan, M; Sinervo, P; Sinev, N B; Sipica, V; Siragusa, G; Sisakyan, A N; Sivoklokov, S Yu; Sjoelin, J; Sjursen, T B; Skubic, P; Skvorodnev, N; Slater, M; Slavicek, T; Sliwa, K; Sloper, J; Sluka, T; Smakhtin, V; Smirnov, S Yu; Smirnov, Y; Smirnova, L N; Smirnova, O; Smith, B C; Smith, D; Smith, K M; Smizanska, M; Smolek, K; Snesarev, A A; Snow, S W; Snow, J; Snuverink, J; Snyder, S; Soares, M; Sobie, R; Sodomka, J; Soffer, A; Solans, C A; Solar, M; Solfaroli-Camillocci, E; Solodkov, A A; Solovyanov, O V; Soluk, R; Sondericker, J; Sopko, V; Sopko, B; Sosebee, M; Sosnovtsev, V V; Sospedra-Suay, L; Soukharev, A; Spagnolo, S; Spanò, F; Speckmayer, P; Spencer, E; Spighi, R; Spigo, G; Spila, F; Spiwoks, R; Spousta, M; Spreitzer, T; Spurlock, B; St Denis, R D; Stahl, T; Stamen, R; Stancu, S N; Stanecka, E; Stanek, R W; Stanescu, C; Stapnes, S; Starchenko, E A; Stark, J; Staroba, P; Starovoitov, P; Stastny, J; Staude, A; Stavina, P; Stavropoulos, G; Steinbach, P; Steinberg, P; Stekl, I; Stelzer, B; Stelzer, H J; Stelzer-Chilton, O; Stenzel, H; Stevenson, K; Stewart, G; Stockton, M C; Stoerig, K; Stoicea, G; Stonjek, S; Strachota, P; Stradling, A; Straessner, A; Strandberg, J; Strandberg, S; Strandlie, A; Strauss, M; Strizenec, P; Ströhmer, R; Strom, D M; Strong, J A; Stroynowski, R; Strube, J; Stugu, B; Stumer, I; Soh, D A; Su, D; Suchkov, S I; Sugaya, Y; Sugimoto, T; Suhr, C; Suk, M; Sulin, V V; Sultansoy, S; Sumida, T; Sun, X; Sundermann, J E; Suruliz, K; Sushkov, S; Susinno, G; Sutton, M R; Suzuki, T; Suzuki, Y; Sviridov, Yu M; Sykora, I; Sykora, T; Szymocha, T; Sánchez, J; Ta, D; Tackmann, K; Taffard, A; Tafirout, R; Taga, A; Takahashi, Y; Takai, H; Takashima, R; Takeda, H; Takeshita, T; Talby, M; Talyshev, A; Tamsett, M C; Tanaka, J; Tanaka, R; Tanaka, S; Tanaka, S; Tappern, G P; Tapprogge, S; Tardif, D; Tarem, S; Tarrade, F; Tartarelli, G F; Tas, P; Tasevsky, M; Tassi, E; Taylor, C; Taylor, F E; Taylor, G N; Taylor, R P; Taylor, W; Teixeira-Dias, P; Ten Kate, H; Teng, P K; Terada, S; Terashi, K; Terron, J; Terwort, M; Testa, M; Teuscher, R J; Tevlin, C M; Thadome, J; Thananuwong, R; Thioye, M; Thoma, S; Thomas, J P; Thomas, T L; Thompson, E N; Thompson, P D; Thompson, P D; Thompson, R J; Thompson, A S; Thomson, E; Thun, R P; Tic, T; Tikhomirov, V O; Tikhonov, Y A; Timmermans, C J W P; Tipton, P; Tique-Aires-Viegas, F J; Tisserant, S; Tobias, J; Toczek, B; Todorov, T; Todorova-Nova, S; Toggerson, B; Tojo, J; Tokár, S; Tokushuku, K; Tollefson, K; Tomasek, L; Tomasek, M; Tomasz, F; Tomoto, M; Tompkins, D; Tompkins, L; Toms, K; Tong, G; Tonoyan, A; Topfel, C; Topilin, N D; Torrence, E; Torró Pastor, E; Toth, J; Touchard, F; Tovey, D R; Tovey, S N; Trefzger, T; Tremblet, L; Tricoli, A; Trigger, I M; Trincaz-Duvoid, S; Trinh, T N; Tripiana, M F; Triplett, N; Trivedi, A; Trocmé, B; Troncon, C; Trzupek, A; Tsarouchas, C; Tseng, J C-L; Tsiafis, I; Tsiakiris, M; Tsiareshka, P V; Tsionou, D; Tsipolitis, G; Tsiskaridze, V; Tskhadadze, E G; Tsukerman, I I; Tsulaia, V; Tsung, J-W; Tsuno, S; Tsybychev, D; Turala, M; Turecek, D; Turk Cakir, I; Turlay, E; Tuts, P M; Twomey, M S; Tylmad, M; Tyndel, M; Tzanakos, G; Uchida, K; Ueda, I; Uhlenbrock, M; Uhrmacher, M; Ukegawa, F; Unal, G; Underwood, D G; Undrus, A; Unel, G; Unno, Y; Urbaniec, D; Urkovsky, E; Urquijo, P; Urrejola, P; Usai, G; Uslenghi, M; Vacavant, L; Vacek, V; Vachon, B; Vahsen, S; Valenta, J; Valente, P; Valentinetti, S; Valkar, S; Valladolid Gallego, E; Vallecorsa, S; Valls Ferrer, J A; Van Berg, R; van der Graaf, H; van der Kraaij, E; van der Poel, E; Van Der Ster, D; van Eldik, N; van Gemmeren, P; van Kesteren, Z; van Vulpen, I; Vandelli, W; Vandoni, G; Vaniachine, A; Vankov, P; Vannucci, F; Varela Rodriguez, F; Vari, R; Varnes, E W; Varouchas, D; Vartapetian, A; Varvell, K E; Vasilyeva, L; Vassilakopoulos, V I; Vazeille, F; Vegni, G; Veillet, J J; Vellidis, C; Veloso, F; Veness, R; Veneziano, S; Ventura, A; Ventura, D; Venturi, M; Venturi, N; Vercesi, V; Verducci, M; Verkerke, W; Vermeulen, J C; Vetterli, M C; Vichou, I; Vickey, T; Viehhauser, G H A; Villa, M; Villani, E G; Villaplana Perez, M; Villate, J; Vilucchi, E; Vincter, M G; Vinek, E; Vinogradov, V B; Viret, S; Virzi, J; Vitale, A; Vitells, O V; Vivarelli, I; Vives Vaques, F; Vlachos, S; Vlasak, M; Vlasov, N; Vogt, H; Vokac, P; Volpi, M; Volpini, G; von der Schmitt, H; von Loeben, J; von Radziewski, H; von Toerne, E; Vorobel, V; Vorobiev, A P; Vorwerk, V; Vos, M; Voss, R; Voss, T T; Vossebeld, J H; Vranjes, N; Vranjes Milosavljevic, M; Vrba, V; Vreeswijk, M; Vu Anh, T; Vudragovic, D; Vuillermet, R; Vukotic, I; Wagner, P; Wahlen, H; Walbersloh, J; Walder, J; Walker, R; Walkowiak, W; Wall, R; Wang, C; Wang, H; Wang, J; Wang, J C; Wang, S M; Ward, C P; Warsinsky, M; Wastie, R; Watkins, P M; Watson, A T; Watson, M F; Watts, G; Watts, S; Waugh, A T; Waugh, B M; Webel, M; Weber, J; Weber, M D; Weber, M; Weber, M S; Weber, P; Weidberg, A R; Weingarten, J; Weiser, C; Wellenstein, H; Wells, P S; Wen, M; Wenaus, T; Wendler, S; Wengler, T; Wenig, S; Wermes, N; Werner, M; Werner, P; Werth, M; Werthenbach, U; Wessels, M; Whalen, K; Wheeler-Ellis, S J; Whitaker, S P; White, A; White, M J; White, S; Whiteson, D; Whittington, D; Wicek, F; Wicke, D; Wickens, F J; Wiedenmann, W; Wielers, M; Wienemann, P; Wiglesworth, C; Wiik, L A M; Wildauer, A; Wildt, M A; Wilhelm, I; Wilkens, H G; Williams, E; Williams, H H; Willis, W; Willocq, S; Wilson, J A; Wilson, M G; Wilson, A; Wingerter-Seez, I; Winklmeier, F; Wittgen, M; Wolter, M W; Wolters, H; Wosiek, B K; Wotschack, J; Woudstra, M J; Wraight, K; Wright, C; Wright, D; Wrona, B; Wu, S L; Wu, X; Wulf, E; Xella, S; Xie, S; Xie, Y; Xu, D; Xu, N; Yamada, M; Yamamoto, A; Yamamoto, S; Yamamura, T; Yamanaka, K; Yamaoka, J; Yamazaki, T; Yamazaki, Y; Yan, Z; Yang, H; Yang, U K; Yang, Y; Yang, Z; Yao, W-M; Yao, Y; Yasu, Y; Ye, J; Ye, S; Yilmaz, M; Yoosoofmiya, R; Yorita, K; Yoshida, R; Young, C; Youssef, S P; Yu, D; Yu, J; Yu, M; Yu, X; Yuan, J; Yuan, L; Yurkewicz, A; Zaidan, R; Zaitsev, A M; Zajacova, Z; Zambrano, V; Zanello, L; Zarzhitsky, P; Zaytsev, A; Zeitnitz, C; Zeller, M; Zema, P F; Zemla, A; Zendler, C; Zenin, O; Zenis, T; Zenonos, Z; Zenz, S; Zerwas, D; Zevi della Porta, G; Zhan, Z; Zhang, H; Zhang, J; Zhang, Q; Zhang, X; Zhao, L; Zhao, T; Zhao, Z; Zhemchugov, A; Zheng, S; Zhong, J; Zhou, B; Zhou, N; Zhou, Y; Zhu, C G; Zhu, H; Zhu, Y; Zhuang, X; Zhuravlov, V; Zilka, B; Zimmermann, R; Zimmermann, S; Zimmermann, S; Ziolkowski, M; Zitoun, R; Zivkovic, L; Zmouchko, V V; Zobernig, G; Zoccoli, A; zur Nedden, M; Zutshi, V

    2010-01-01

    The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing performance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolution. The uniformity of the electromagnetic barrel calorimeter response along eta (averaged over phi) is measured at the percent level using minimum ionizing cosmic muons. Finally, studies of electromagnetic showers from radiative muons have been used to cross-check the Monte Carlo simulation. The performance results obtained u...

  13. Breakdown voltage of metal-oxide resistors in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Bagby, L. F. [Fermilab; Gollapinni, S. [Kansas State U.; James, C. C. [Fermilab; Jones, B. J.P. [MIT; Jostlein, H. [Fermilab; Lockwitz, S. [Fermilab; Naples, D. [Pittsburgh U.; Raaf, J. L. [Fermilab; Rameika, R. [Fermilab; Schukraft, A. [Fermilab; Strauss, T. [Bern U., LHEP; Weber, M. S. [Bern U., LHEP; Wolbers, S. A. [Fermilab

    2014-11-07

    We characterized a sample of metal-oxide resistors and measured their breakdown voltage in liquid argon by applying high voltage (HV) pulses over a 3 second period. This test mimics the situation in a HV-divider chain when a breakdown occurs and the voltage across resistors rapidly rise from the static value to much higher values. All resistors had higher breakdown voltages in liquid argon than their vendor ratings in air at room temperature. Failure modes range from full destruction to coating damage. In cases where breakdown was not catastrophic, subsequent breakdown voltages were lower in subsequent measuring runs. One resistor type withstands 131 kV pulses, the limit of the test setup.

  14. A pressurized argon gas TPC as DUNE near detector

    CERN Document Server

    Martin-Albo, J

    2016-01-01

    DUNE is a new international experiment for neutrino physics and nucleon decay searches. It will consist of two detectors, about 1300 km apart, exposed to a multi-megawatt neutrino beam that will be built at Fermilab. One of the two detectors will be installed several hundred meters downstream of the neutrino production point with the primary role of characterising the energy spectrum and composition of the beam as well as performing precision measurements of neutrino cross sections. For the design of this so-called near detector, the DUNE Collaboration is considering, among other technologies, a pressurized argon gas time projection chamber. Such a detector, thanks to its low density and low detection thresholds, would allow the detailed measurement in argon of nuclear effects at the neutrino interaction vertex, which are considered at present one of the most important sources of systematic uncertainty for neutrino oscillation measurements.

  15. Opacity measurements in shock-generated argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.

    1993-07-01

    Dense plasmas having uniform and constant density and temperature are generated by passage of a planar shock wave through gas. The opacity of the plasma is accurately measured versus wavelength by recording the risetime of emitted light. This technique is applicable to a wide variety of species and plasma conditions. Initial experiments in argon have produced plasmas with 2 eV temperatures, 0.004--0.04 g/cm{sup 3} densities, and coupling parameters {Gamma} {approximately}0.3--0.7. Measurements in visible light are compared with calculations using the HOPE code. An interesting peak in the capacity at 400 nm is observed for the first time and is identified with the 4s-5p transition in excited neutral argon atoms.

  16. Treatment of facial vascular lesions with an argon laser

    Science.gov (United States)

    Szymanczyk, Jacek; Golebiowska, Aleksandra; Michalska, I.

    1996-03-01

    Two-hundred-ninety-six patients with various vascular lesions of the face have been treated with argon laser LAK-1 in the Department of Dermatology Warsaw Medical Academy since April 1992. The diagnosis of the treated lesions was port-wine stains, multiple telangiectasiae and small, most often induced by trauma hemangioma cavernosum of the lip. Best results were achieved in the patients with small hemangiomas cavernosum of the lip and multiple telangiectasiae on the face. Cure rate in this group was 100%. In 112 port-wine stain cases fading of 50 - 75% comparing with the adjacent skin was achieved. With stress, the argon laser therapy is a method of choice for the treatment of hemangioma cavernosum, port-wine stains and multiple teleagiectasiae of the face.

  17. Development of cryogenic installations for large liquid argon neutrino detectors

    CERN Document Server

    Adamowski, M; Geynisman, M; Hentschel, S; Montanari, D; Nessi, M; Norris, B

    2015-01-01

    A proposal for a very large liquid argon (68,000 kg) based neutrino detector is being studied. To validate the design principles and the detector technology, and to gain experience in the development of the cryostats and the cryogenic systems needed for such large experiments, several smaller scale installations will be developed and implemented, at Fermilab and CERN. The cryogenic systems for these installations will be developed, constructed, installed and commissioned by an international engineering team. These installations shall bring the required cooling power under specific conditions to the experiments for the initial cool-down and the long term operation, and shall also guarantee the correct distribution of the cooling power within the cryostats to ensure a homogeneous temperature distribution within the cryostat itself. The cryogenic systems shall also include gaseous and liquid phase argon purification devices to be used to reach and maintain the very stringent purity requirements needed for these...

  18. Nitriding behavior of Ni and Ni-based binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fonovic, Matej

    2015-01-15

    Gaseous nitriding is a prominent thermochemical surface treatment process which can improve various properties of metallic materials such as mechanical, tribological and/or corrosion properties. This process is predominantly performed by applying NH{sub 3}+H{sub 2} containing gas atmospheres serving as the nitrogen donating medium at temperatures between 673 K and 873 K (400 C and 600 C). NH{sub 3} decomposes at the surface of the metallic specimen and nitrogen diffuses into the surface adjacent region of the specimen whereas hydrogen remains in the gas atmosphere. One of the most important parameters characterizing a gaseous nitriding process is the so-called nitriding potential (r{sub N}) which determines the chemical potential of nitrogen provided by the gas phase. The nitriding potential is defined as r{sub N} = p{sub NH{sub 3}}/p{sub H{sub 2}{sup 3/2}} where p{sub NH{sub 3}} and p{sub H{sub 2}} are the partial pressures of the NH{sub 3} and H{sub 2} in the nitriding atmosphere. In contrast with nitriding of α-Fe where the nitriding potential is usually in the range between 0.01 and 1 atm{sup -1/2}, nitriding of Ni and Ni-based alloys requires employing nitriding potentials higher than 100 atm{sup -1/2} and even up to ∞ (nitriding in pure NH{sub 3} atmosphere). This behavior is compatible with decreased thermodynamic stability of the 3d-metal nitrides with increasing atomic number. Depending on the nitriding conditions (temperature, nitriding potential and treatment time), different phases are formed at the surface of the Ni-based alloys. By applying very high nitriding potential, formation of hexagonal Ni{sub 3}N at the surface of the specimen (known as external nitriding) leads to the development of a compound layer, which may improve tribological properties. Underneath the Ni{sub 3}N compound layer, two possibilities exist: (i) alloying element precipitation within the nitrided zone (known as internal nitriding) and/or (ii) development of metastable and

  19. Spectroscopy of Argon Excited in an Electron Beam Ion Trap

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2005-04-18

    Argon is one of the gases best investigated and most widely used in plasma discharge devices for a multitude of applications that range from wavelength reference standards to controlled fusion experiments. Reviewing atomic physics and spectroscopic problems in various ionization stages of Ar, the past use and future options of employing an electron beam ion trap (EBIT) for better and more complete Ar data in the x-ray, EUV and visible spectral ranges are discussed.

  20. Influence of argon pollution on the weld surface morphology

    OpenAIRE

    Krolczyk, G.M.; Nieslony, P.; Krolczyk, J.B.; I. Samardzic; Legutko, S.; S. Hloch; Barrans, Simon; Maruda, R.W.

    2015-01-01

    In this paper the surfaces of butt welded joints in steel tubes were analyzed using an optical 3D measurement system to determine the morphology and topographic parameters. It was established that pollution of the argon shield gas with oxygen did not influence the width of the heat-affected zone. However, the composition of the shield gas significantly influenced the surface asymmetry, Ssk, and its inclination Sku. The measurement of these parameters enabled the selection of a ...

  1. STATUS OF THE ATLAS LIQUID ARGON CALORIMETER AND ITS PERFORMANCE

    CERN Document Server

    Berillari, T; The ATLAS collaboration

    2011-01-01

    The liquid argon (LAr) calorimeters are used in ATLAS for all electromagnetic and for hadron calorimetry. The LAr calorimeter system consists of an electromagnetic barrel calorimeter and two endcaps with electromagnetic, hadronic and forward calorimeters. The latest status of the detector as well as problems and solutions addressed during the last years will be presented. Aspects of operation of a large detector over a long time period will be summarized and selected topics showing the performance of the detector will be shown.

  2. Thermal decomposition of lanthanum(III) butyrate in argon atmosphere

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Yue, Zhao; Xiao, Tang;

    2013-01-01

    The thermal decomposition of La(C3H7CO2)3·xH2O (x≈0.82) was studied in argon during heating at 5K/min. After the loss of bound H2O, the anhydrous butyrate presents at 135°C a phase transition to a mesophase, which turns to an isotropic liquid at 180°C. The decomposition of the anhydrous butyrate ...

  3. Operational performance of a large liquid argon photon calorimeter

    International Nuclear Information System (INIS)

    We describe the performance of a large (0.9x1.4 m2) liquid argon photon calorimeter in high energy experiments at Fermilab. Resolutions for π0 and electron showers, obtained under data-taking conditions, are compared with electron-beam calibration results. Exceptional spatial and time resolutions have been achieved for isolated showers (sigmasub(x,y)0 data up to 180 GeV are presented. (orig.)

  4. Unified set of atomic transition probabilities for neutral argon

    OpenAIRE

    Wiese, W.; Brault, J.; Danzmann, K.; Helbig, V.; de Kock, M

    1989-01-01

    The atomic transition probabilities and radiative lifetimes of neutral argon have been the subject of numerous experiments and calculations, but the results exhibit many discrepancies and inconsistencies. We present a unified set of atomic transition probabilities, which is consistent with essentially all recent results, albeit sometimes only after critical reanalysis. The data consistency and scale confirmation has been achieved in two ways. (i) We have carried out some lifetime–branching-ra...

  5. Monte Carlo Simulation of Argon in Nano-Space

    Institute of Scientific and Technical Information of China (English)

    CHEN Min; YANG Chun; GUO Zeng-Yuan

    2000-01-01

    Monte Carlo simulations are performed to investigate the thermodynamic properties of argon confined in nano-scale cubes constructed of graphite walls. A remarkable depression of the system pressures is observed. The simulations reveal that the length-scale of the cube, the magnitude of the interaction between the fluid and the graphite wall and the density of the fluid exhibit reasonable effects on the thermodynamic property shifts of the luid.

  6. Two dimensional condensation of argon adsorbed on lamellar halides

    International Nuclear Information System (INIS)

    Lamellar halides such as NiCl2, FeCl2, NiBr2, MnBr2, MgBr2, CdBr2, CoI2, FeI2, MnI2, CaI2 and PbI2 were sublimed in a rapid stream of dry nitrogen. The adsorption of argon on such materials shows stepped isotherms which reveal two dimensional condensations. From sets of isotherms the Helmholtz free energy, the internal energy and the entropy of the successive layers are determined. From the entropy of the first layer the role of the potential relief of the adsorbent surface on the structure of the adsorbed layer may be determined while the Helmholtz free energy reveals how the ionic character of the adsorbent governs the attractive force of adsorption. The study of the second third and fourth layers shows that their growth follows quite a different behaviour depending on whether the Van der Waals diameter of argon is greater or smaller than the distance between adjacent anions on the crystal surface. A proposition is made to account for the difference in the critical temperatures of the first and second dense layers in terms of the vibrationnal state of their respective substrate. The occurence for the maximum critical temperature observed of corresponding to a triangular layer 3% more expanded than the (111) plane of solid argon is discussed

  7. A liquid argon scintillation veto for the Gerda experiment

    Energy Technology Data Exchange (ETDEWEB)

    Wegmann, Anne [Max-Planck Institut fuer Kernphysik, Heidelberg (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    Gerda is an experiment to search for the neutrinoless double beta decay of {sup 76}Ge. Bare germanium detectors are operated in a cryostat with 65 m{sup 3} of liquid argon (LAr). To reach the aspired background index of ≤10{sup -3} cts/(keV.kg.yr) for Phase II active background-suppression techniques will be applied, including an active liquid argon veto (LAr veto). A light instrumentation of LAr installed in the LArGe test facility has demonstrated that the detection of argon scintillation light can be used to effectively suppress background events in the germanium, which simultaneously deposit energy in LAr. Based on these results, Gerda pursues several options for the light instrumentation, which have to be compatible with the stringent radiopurity requirements of the experiment and should provide a significant suppression of the background in the region of interest around Q{sub ββ} at 2039 keV. This talk gives an account of the competing design options under investigation in the Gerda collaboration. The design options using photomultiplier tubes (PMT) and silicon photomultipliers (SiPM) are discussed, together with their expected performance from Monte Carlo simulations. In addition, the progress of development is reported, along with the design criteria for light instrumentation in Gerda.

  8. A liquid argon scintillation veto for the Gerda experiment

    International Nuclear Information System (INIS)

    Gerda is an experiment to search for the neutrinoless double beta decay of 76Ge. Bare germanium detectors are operated in a cryostat with 65 m3 of liquid argon (LAr). To reach the aspired background index of ≤10-3 cts/(keV.kg.yr) for Phase II active background-suppression techniques will be applied, including an active liquid argon veto (LAr veto). A light instrumentation of LAr installed in the LArGe test facility has demonstrated that the detection of argon scintillation light can be used to effectively suppress background events in the germanium, which simultaneously deposit energy in LAr. Based on these results, Gerda pursues several options for the light instrumentation, which have to be compatible with the stringent radiopurity requirements of the experiment and should provide a significant suppression of the background in the region of interest around Qββ at 2039 keV. This talk gives an account of the competing design options under investigation in the Gerda collaboration. The design options using photomultiplier tubes (PMT) and silicon photomultipliers (SiPM) are discussed, together with their expected performance from Monte Carlo simulations. In addition, the progress of development is reported, along with the design criteria for light instrumentation in Gerda.

  9. Space-charge effects in liquid argon ionization chambers

    Science.gov (United States)

    Rutherfoord, J. P.; Walker, R. B.

    2015-03-01

    We have uniformly irradiated liquid argon ionization chambers with betas from high-activity 90Sr sources. The radiation environment is similar to that in the liquid argon calorimeters which are part of the ATLAS detector installed at CERN's Large Hadron Collider (LHC). We measured the resulting ionization current over a wide range of applied potential for two different source activities and for three different chamber gaps. These studies provide operating experience at exceptionally high ionization rates. In particular they indicate a stability at the 0.1% level for these calorimeters over years of operation at the full LHC luminosity when operated in the normal mode at an electric field E = 1.0 kV / mm. We can operate these chambers in the normal mode or in the space-charge limited regime and thereby determine the transition point between the two. This transition point is parameterized by a positive argon ion mobility of μ+ = 0.08 ± 0.02mm2 / V s at a temperature of 88.0±0.5 K and at a pressure of 1.02±0.02 bar. In the space-charge limited regime the ionization currents are degraded and show signs of instability. At the highest electric fields in our study (6.7 kV/mm) the ionization current is still slowly rising with increasing electric field.

  10. ARAPUCA a new device for liquid argon scintillation light detection

    International Nuclear Information System (INIS)

    We present a totally innovative device for the detection of liquid argon scintillation light, that has been named ARAPUCA (Argon R and D Advanced Program at UniCAmp). It is composed of a passive light collector and of active devices. The latters are standard SiPMs that operate at liquid argon temperature, while the passive collector is based on a new technology, never explored in this field before. It is a photon trap, that allows to collect light with extremely high efficiency. The total detection efficiency of the device can be tuned by modifying the ratio between the area of the active devices (SiPM) and the area of the optical window. For example, it will allow to reach a detection efficiency at the level of 1% on a surface of 50 × 50 cm2 with an active coverage of 2 × 2 cm2 (two/three large area SiPM). It is also a cheap device, since the major part of its cost is represented by the active devices. For these reason this appears to be the ideal device for scintillation light detection in large Time Projection Chambers. With appropriate modifications it can be used also in next generation Dark Matter detectors

  11. Isotopic fractionation of argon during stepwise release from shungite

    International Nuclear Information System (INIS)

    In previous attempts to determine the 40Ar/36Ar ratio in the ancient atmosphere, the only direct measurement yielding a value below the atmospheric value of today is for argon released at low temperatures from a pre-Cambrian shungite, an amorphous carbon mineral The present work confirms a low value for 40Ar/36Ar in gas released from a type I shungite at low temperatures. But quantitative scrutiny of the accompanying 38AR/36Ar ratios and the enhanced ratio of 40Ar/36Ar for the fractions released at high temperatures shows convincingly that the effect seen here is an artifact of the stepwise heating and the argon diffusion mobilized thereby. The low 40Ar/36Ar previously obtained is very likely from the same cause rather than reflecting the isotopic composition of the pre-Cambrian atmosphere. The vitreous character of and the sharp, conchoidal fractures seen in the specimens of type I shungite suggest that the substance may exhibit simple volume diffusion over macroscopic dimensions as glasses do. If so, the diffusion parameters (D infinitely = 3 x 10-4 cm2/s and E = 11 kcal/mole) obtained from the data imply rapid exchange with the atmosphere for any argon initially trapped in centimenter-thick veins of the material. (orig.)

  12. Isotopic fractionation of argon during stepwise release from shungite

    Science.gov (United States)

    Rison, W.

    1980-05-01

    It is noted that in previous attempts to determine the Ar-40/Ar-36 ratio in the ancient atmosphere, the only direct measurement yielding a value below the atmospheric value of today is for argon released at low temperatures from a pre-Cambrian shungite. In the present work, a low value for Ar-40/Ar-36 in gas released from a type I shungite at low temperatures is confirmed. Attention is given to a study of the accompanying Ar-38/Ar-36 ratios and the enhanced ratio of Ar-40/Ar-36 for the fractions released at high temperatures which shows that the effect observed is a result of the stepwise heating and the argon diffusion mobilized thereby. It is suggested that the low Ar-40/Ar-36 obtained in the past is from the same source rather than reflecting the isotropic composition of the pre-Cambrian atmosphere, and that the type I shungite may exhibit simple volume diffusion over macroscopic dimensions as glasses do. It is concluded that if this is so, the diffusion parameters obtained from the data would imply rapid exchange with the atmosphere for any argon initially trapped in the veins of the material.

  13. Tin LPP plasma control in the argon cusp source

    Science.gov (United States)

    McGeoch, Malcolm W.

    2016-03-01

    The argon cusp plasma has been introduced [1,2] for 500W class tin LPP exhaust control in view of its high power handling, predicted low tin back-scatter from a beam dump, and avoidance of hydrogen usage. The physics of tin ion control by a plasma is first discussed. Experimentally, cusp stability and exhaust disc geometry have previously been proved at full scale [2], the equivalent of 300W-500W usable EUV. Here we verify operation of the plasma barrier that maintains a high argon density next to the collector, for its protection, and a low density in the long path toward the intermediate focus, for efficiency. A pressure differential of 2Pa has been demonstrated in initial work. Other aspects of tin LPP plasma control by the cusp have now been demonstrated using tin ions from a low Hz 130mJ CO2 laser pulse onto a solid tin surface at the cusp center. Plasma is rejected at the design to match a specified exhaust power is discussed. In view of this work, argon cusp exhaust control appears to be very promising for 500W class tin LPP sources.

  14. Bacteria Inactivation Using DBD Plasma Jet in Atmospheric Pressure Argon

    Institute of Scientific and Technical Information of China (English)

    XU Guimin; ZHANG Guanjun; SHI Xingmin; MA Yue; WANG Ning; LI Yuan

    2009-01-01

    A coaxial dielectric barrier discharge plasma jet Was designed,which can be operated in atmospheric pressure argon under an intermediate frequency sinusoidal resonant power supply,and an atmospheric pressure glow-like discharge Was achieved.Two kinds of typical bacteria,i.e.,the Staphylococcus aureus(S.aurens)and Escherichia coil(E.coil),were employed to study the bacterial inactivation mechanism by means of the non-thermal plasma.The killing log value (KLV)of S.aureus reached up to 5.38 with a treatment time of 90 s and that of E.coil up to 5.36 with 60 s,respectively.According to the argon emission spectra of the plasma jet and the scanning electron microscope (SEM) images of the two bacteria before and after the plasma treatment.it is concluded that the reactive species in the argon plasma played a major role in the bacterial inactivation,while the heat,electric field and UV photons had little effect.

  15. Metal clusters on supported argon layers; Metallcluster auf dielektrischen Substraten

    Energy Technology Data Exchange (ETDEWEB)

    Faber, Bernhard

    2011-10-21

    The deposition of small sodium clusters on supported Ar(001)-surfaces is simulated. Theoretical description is achieved by a hierarchical model consisting of time-dependent DFT and molecular dynamics. The valence electrons of the sodium atoms are considered by Kohn-Sham-Scheme with self interaction correction. The interaction of argon atoms and sodium ions is described by atom-atom potentials whereas the coupling to the QM electrons is done by local pseudo-potentials. A decisive part of the model is the dynamical polarizability of the rare-gas atoms. The optional metal support is considered by the method of image charges. The influence of the forces caused by image charges and the influence of the number of argon monolayers on structure, optical response and deposition dynamics of Na{sub 6} and Na{sub 8} is investigated. There is very little influence on cluster structure and only a small shift of the cluster perpendicular to the surface. Concerning optical response the position of the Mie plasmon peak stays robust whereas the details of spectral fragmentation react very sensitively to changes. The forces caused by image charges of the metal support play only a little role with the dynamics of deposition while the thickness of the argon surface strongly influences the dissipation. (orig.)

  16. Examination of Plasma Nitriding Microstructure with Addition of Rare Earths

    Institute of Scientific and Technical Information of China (English)

    张津

    2004-01-01

    Medium-carbon alloy steel was plasma nitrided with rare earths La,Ce and Nd into the nitriding chamber respectively.The nitriding layer microstructures with and without rare earths were compared using optical microscope,normal SEM and high resolution SEM,as well as TEM.It was found that the extent of the influence on plasma nitriding varies with different contents of rare earth.The effect of plasma nitriding is benefit from adding of Ce or Nd.The formation of hard and brittle phase Fe2-3N can be prevented and the butterfly-like structure can be improved by adding Ce or Nd.However,pure La may prevent the diffusion of nitrogen and the formation of iron nitride,and reduce the depth of diffusion layer.

  17. Liquid flow cells having graphene on nitride for microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Adiga, Vivekananda P.; Dunn, Gabriel; Zettl, Alexander K.; Alivisatos, A. Paul

    2016-09-20

    This disclosure provides systems, methods, and apparatus related to liquid flow cells for microscopy. In one aspect, a device includes a substrate having a first and a second oxide layer disposed on surfaces of the substrate. A first and a second nitride layer are disposed on the first and second oxide layers, respectively. A cavity is defined in the first oxide layer, the first nitride layer, and the substrate, with the cavity including a third nitride layer disposed on walls of the substrate and the second oxide layer that define the cavity. A channel is defined in the second oxide layer. An inlet port and an outlet port are defined in the second nitride layer and in fluid communication with the channel. A plurality of viewports is defined in the second nitride layer. A first graphene sheet is disposed on the second nitride layer covering the plurality of viewports.

  18. The Study of Plasma Nitriding of AISI304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; JI Shi-jun; GAO Yu-zhou; SUN Jun-cai

    2004-01-01

    This paper presents results on the plasma nitriding of AISI 304 stainless steel at different temperatures in NH 3 gas. The working pressure was 100~200 Pa and the discharge voltage was 700~800V. The phase of nitrided layer formed on the surface was confirmed by X-ray diffraction. The hardness of the samples was measured by using a Vickers microhardness tester with the load of 50g. After nitriding at about 400 ℃ for two hours a nitrided layer consisting of single γN phase with thickness of 5μm was obtained. Microhardness measurements showed significant increase in the hardness from 240 HV (for untreated samples) up to 950 HV (for nitrided samples at temperature of 420℃). The phase composition, the thickness, the microstructure and the surface topography of the nitrided layer as well as its properties depend essentially on the process parameters.

  19. K-Ar age of young volcanic rocks and excess argon--Binary mixing model and quantitative study of excess argon effect

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A binary mixing model for excess argon is suggested in the note. According to this model and the data of excess argon component obtained in our experiment , a quantitative study of the effect of excess argon on real K-Ar age of young volcanic rocks is done. The result indicates that the effect of 5% excess argon component in samples on K-Ar age of the samples more than 2 Ma is less than 7.36% and can lead K-Ar age of 0.5 Ma samples to increase by 32.4%, while 1% excess argon component leads K-Ar age of 0.5 Ma samples to increase by 6.26%. Therefore, when pre-processed excess argon component is ≤1%, K-Ar age of the samples more than 0.5 Ma should be credible. On this basis we suggest a principal opinion for evaluation of previous K-Ar dating results and propose that the matrix is used to determine K-Ar age of young volcanic rocks. For the samples less than 0.2 Ma, in the case of high excess argon content, even if only 1% excess argon component exists in their matrix, it can also greatly affect their K-A age. Thus it must be careful to treat the dating result.

  20. An assessment of the thermodynamic properties of uranium nitride, plutonium nitride and uranium-plutonium mixed nitride

    International Nuclear Information System (INIS)

    Thermodynamic properties such as vapour pressures, heat capacities and enthalpies of formation for UN(s), PuN(s) and (U, Pu)N(s) are critically evaluated. The equations of the vapour pressures and the heat capacities for the three nitrides are assessed. Thermal functions, and thermodynamic functions for the formation of UN(s), PuN(s) and (U, Pu)N(s), are calculated

  1. Intragranular Chromium Nitride Precipitates in Duplex and Superduplex Stainless Steel

    OpenAIRE

    Iversen, Torunn Hjulstad

    2012-01-01

    Intragranular chromium nitrides is a phenomenon with detrimental effects on material properties in superduplex stainless steels which have not received much attention. Precipitation of nitrides occurs when the ferritic phase becomes supersaturated with nitrogen and there is insufficient time during cooling for diffusion of nitrogen into austenite. Heat treatment was carried out at between 1060◦C and 1160◦C to study the materials susceptibility to nitride precipitation with...

  2. Roles of argon seeding in energy confinement and pedestal structure in JT-60U

    International Nuclear Information System (INIS)

    The mechanism of improving energy confinement with argon seeding at high density has been investigated in JT-60U. Better confinement is sustained at high density by argon seeding accompanied by higher core and pedestal temperatures. The electron density profiles become flatter with increasing density in conventional H-mode plasmas, whereas peaked density profiles are maintained with argon seeding. Density peaking and dilution effects lower the pedestal density at a given averaged density. The pedestal density in the argon seeded plasmas, which is lower than that in plasmas with deuterium puff, enables the pedestal temperature to be higher, whereas the increase in the pedestal pressure with argon seeding is small. High pedestal temperature is a boundary condition for high core temperature through profile stiffness, which leads to better confinement with argon seeding. The density peaking is a key factor of sustaining better confinement in argon seeded H-mode plasmas. The radiative loss power density is predominantly enhanced in the edge region by argon puff. The role of argon seeding in the pedestal characteristics has also been examined. The pedestal width becomes larger continuously with edge collisionality, but is nearly independent of the presence of argon seeding. (paper)

  3. Argon-41 production and evolution at the Oregon State University TRIGA Reactor (OSTR)

    International Nuclear Information System (INIS)

    In this study, argon-41 concentrations were measured at various locations within the reactor facility to assess the accuracy of models used to predict argon-41 evolution from the reactor tank, and to determine the relationship between argon gas evolution from the tank and subsequent argon-41 concentrations throughout the reactor room. In particular, argon-41 was measured directly above the reactor tank with the reactor tank lids closed, at other accessible locations on the reactor top with the tank lids both closed and open, and at several locations on the first floor of the reactor room. These measured concentrations were then compared to values calculated using a modified argon-41 production and evolution model for TRIGA reactor tanks and ventilation values applicable to the OSTR facility. The modified model was based in part on earlier TRIGA models for argon-41 production and release, but added features which improved the agreement between predicted and measured values. The approximate dose equivalent rate due to the presence of argon-41 in reactor room air was calculated for several different locations inside the OSTR facility. These dose rates were determined using the argon-41 concentration measured at each specific location, and were subsequently converted to a predicted quarterly dose equivalent for each location based on the reactor's operating history. The predicted quarterly dose equivalent values were then compared to quarterly doses measured by film badges deployed as dose-integrating area radiation monitors at the locations of interest. The results indicate that the modified production and evolution model is able to predict argon-41 concentrations to within a factor of ten when compared to the measured data. Quarterly dose equivalents calculated from the measured argon-41 concentrations and the reactor's operating history seemed consistent with results obtained from the integrating area radiation monitors. Given the argon-41 concentrations measured

  4. Synthesis of two-dimensional titanium nitride Ti4N3 (MXene)

    Science.gov (United States)

    Urbankowski, Patrick; Anasori, Babak; Makaryan, Taron; Er, Dequan; Kota, Sankalp; Walsh, Patrick L.; Zhao, Mengqiang; Shenoy, Vivek B.; Barsoum, Michel W.; Gogotsi, Yury

    2016-06-01

    We report on the synthesis of the first two-dimensional transition metal nitride, Ti4N3-based MXene. In contrast to the previously reported MXene synthesis methods - in which selective etching of a MAX phase precursor occurred in aqueous acidic solutions - here a molten fluoride salt is used to etch Al from a Ti4AlN3 powder precursor at 550 °C under an argon atmosphere. We further delaminated the resulting MXene to produce few-layered nanosheets and monolayers of Ti4N3Tx, where T is a surface termination (F, O, or OH). Density functional theory calculations of bare, non-terminated Ti4N3 and terminated Ti4N3Tx were performed to determine the most energetically stable form of this MXene. Bare and functionalized Ti4N3 are predicted to be metallic. Bare Ti4N3 is expected to show magnetism, which is significantly reduced in the presence of functional groups.We report on the synthesis of the first two-dimensional transition metal nitride, Ti4N3-based MXene. In contrast to the previously reported MXene synthesis methods - in which selective etching of a MAX phase precursor occurred in aqueous acidic solutions - here a molten fluoride salt is used to etch Al from a Ti4AlN3 powder precursor at 550 °C under an argon atmosphere. We further delaminated the resulting MXene to produce few-layered nanosheets and monolayers of Ti4N3Tx, where T is a surface termination (F, O, or OH). Density functional theory calculations of bare, non-terminated Ti4N3 and terminated Ti4N3Tx were performed to determine the most energetically stable form of this MXene. Bare and functionalized Ti4N3 are predicted to be metallic. Bare Ti4N3 is expected to show magnetism, which is significantly reduced in the presence of functional groups. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02253g

  5. Synthesis of Uranium nitride powders using metal uranium powders

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N{sup 15} gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work.

  6. Low temperature gaseous nitriding and carburising of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A.J.

    2005-01-01

    The response of various austenitic and duplex stainless steel grades to low temperature gaseous nitriding and carburising was investigated. Gaseous nitriding was performed in ammonia/hydrogen mixtures at temperatures ,723 K; gaseous carburising was carried out in carbon monoxide/hydrogen mixtures...... for temperatures (783 K. The case developed by thermochemical treatment was examined using reflected light microscopy, X-ray diffraction analysis and microhardness testing. Both nitriding and carburising led to the development of expanded austenite in the surface adjacent zone, irrespective of the phase...... constitution of the substrate. A two step process, consisting of carburising followed by nitriding, provides great flexibility with regard to adjusting the hardness–depth profile....

  7. Quantum chemistry and atomistic simulations of solid nitrides

    OpenAIRE

    Eck, Bernhard

    2000-01-01

    The present thesis covers, at first, the binary nitrides of the the 3d transition metals. Based on their electronic band structures and bonding analyses for the sodium chloride as well as the zinc blend structure type it is then determined why the early nitrides crystallize in the NaCl structure while Fe- and Co-nitride adopt the ZnS structure. Thereafter all stoichiometrically well-defined iron nitrides are theoretically investigated, in particular with respect to the influence of the nitrog...

  8. Review of actinide nitride properties with focus on safety aspects

    Energy Technology Data Exchange (ETDEWEB)

    Albiol, Thierry [CEA Cadarache, St Paul Lez Durance Cedex (France); Arai, Yasuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-12-01

    This report provides a review of the potential advantages of using actinide nitrides as fuels and/or targets for nuclear waste transmutation. Then a summary of available properties of actinide nitrides is given. Results from irradiation experiments are reviewed and safety relevant aspects of nitride fuels are discussed, including design basis accidents (transients) and severe (core disruptive) accidents. Anyway, as rather few safety studies are currently available and as many basic physical data are still missing for some actinide nitrides, complementary studies are proposed. (author)

  9. Investigation of surface properties of high temperature nitrided titanium alloys

    OpenAIRE

    Koyuncu, E.; F. Kahraman; Ö. Karadeniz

    2009-01-01

    Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys.Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, ...

  10. Low Temperature Gaseous Nitriding of Ni-based Superalloys

    DEFF Research Database (Denmark)

    Eliasen, K.M.; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2009-01-01

    In the present work the nitriding response of selected Ni-based superalloys at low temperatures is addressed. The alloys investigated are Nimonic series no. 80, 90, 95 and 100 and Nichrome (Ni:Cr » 80:20). Systematic nitriding experiments at different temperatures were carried out in a thermo...... balance. The morphology of the “case” developed upon low temperature nitriding of Ni-based superalloys was characterised with reflected light microscopy, scanning electron microscopy and X-ray diffraction analysis. The alloy composition proved to have a major influence on the nitriding response...

  11. Atomic-layer deposition of silicon nitride

    CERN Document Server

    Yokoyama, S; Ooba, K

    1999-01-01

    Atomic-layer deposition (ALD) of silicon nitride has been investigated by means of plasma ALD in which a NH sub 3 plasma is used, catalytic ALD in which NH sub 3 is dissociated by thermal catalytic reaction on a W filament, and temperature-controlled ALD in which only a thermal reaction on the substrate is employed. The NH sub 3 and the silicon source gases (SiH sub 2 Cl sub 2 or SiCl sub 4) were alternately supplied. For all these methods, the film thickness per cycle was saturated at a certain value for a wide range of deposition conditions. In the catalytic ALD, the selective deposition of silicon nitride on hydrogen-terminated Si was achieved, but, it was limited to only a thin (2SiO (evaporative).

  12. Aluminum Reduction and Nitridation of Bauxite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhikuan; ZHANG Dianwei; XU Enxia; HOU Xinmei; DONG Yanling

    2007-01-01

    The application of bauxite with low Al2O3 content has been studied in this paper and β-SiAlON has been obtained from two kinds of bauxites (Al203 content 68.08 mass% and 46.30 mass% respectively) by aluminum reduction and nitridation method.The sequence of reactions has been studied using thermal analysis (TG-DTA),X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) with EDS.Compared with carbon thermal reduction and nitridation of aluminosilicates employed presently,the reaction in the system of bauxite-Al-N2 occurs at lower temperature.β-SiAlON appears as one of the main products from 1573K and exists' stably in the range of the present experimental temperature.The microstructure of β-SiAlON obtained at 1773 K is short column with 5-10μm observed by SEM.

  13. Local residual stress measurements on nitride layers

    Energy Technology Data Exchange (ETDEWEB)

    Mansilla, C.; Ocelík, V.; De Hosson, J.Th.M., E-mail: j.t.m.de.hosson@rug.nl

    2015-06-11

    In this work, local stresses in different nitrided maraging steel samples of high practical interest for industrial applications were studied through the so-called micro-slit milling method using a focused ion beam. The nitrogen concentration profiles were acquired by glow discharge optical emission spectroscopy. The residual stress state was measured on the surface and also in cross-section, i.e. examining effects of the nitrogen concentration gradient. It is shown that an enhanced lateral resolution can be achieved when a novel multiple fitting approach is employed. The results presented show an overall agreement with stress profiles obtained by X-ray diffraction. Finite Element Modeling is used to explain the apparent discrepancies. A clear correlation between the residual stress and nitriding profiles has been found and the applicability of this method is shown in particular when stress gradients are present.

  14. Sheath Characteristic in ECR Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The sheath plasma characteristics changing with the negative bias applied to the substrate during electron cyclotron resonance plasma nitriding are studied. The sheath characteristics obtained by a Langmuir single probe and an ion energy analyzer show that when the negative bias applied to the substrate is increasing, the most probable energy of ions in the sheath and the full width of half maximum of ions energy distribution increase, the thickness of the sheath also increases, whereas the saturation current of ion decreases. It has been found from the optical emission spectrum that there are strong lines of N2 and N2+. Based on our experiment results the mechanism of plasma nitriding is discussed.

  15. Silicon Nitride Balls For Cryogenic Bearings

    Science.gov (United States)

    Butner, Myles F.; Ng, Lillian W.

    1990-01-01

    Resistance to wear greater than that of 440C steel. Experiments show lives of ball bearings immersed in liquid nitrogen or liquid oxygen increased significantly when 440C steel balls (running on 440C steel races) replaced by balls of silicon nitride. Developed for use at high temperatures, where lubrication poor or nonexistent. Best wear life of any bearing tested to date and ball material spalls without fracturing. Plans for future tests call for use of liquid oxygen as working fluid.

  16. Magnetron sputtering of thin nitride films

    OpenAIRE

    Kola, Prashanthi V

    1995-01-01

    The objective in this investigation was to design and commission a magnetron sputter deposition system and investigate the properties of hard coatings for mechanical and biomedical applications. The deposition of titanium (Ti) and titanium nitride (TiN) was undertaken as part of the commissioning tests and further work was conducted on the effect of the deposition parameters on the properties of TiN, specifically for biocompatible applications. A thorough understanding of the deposition proce...

  17. Nitride phosphors and solid-state lighting

    CERN Document Server

    Xie, Rong-Jun; Hirosaki, Naoto

    2011-01-01

    Introduction to Solid-State LightingBasics of Solid-State LightingBasics of White Light-Emitting Diodes (LEDs)Applications of Solid-State LightingIntroduction to LuminescenceClassification of Optical ProcessesFundamentals of LuminescenceLuminescent CentersMeasurement of LuminescenceTraditional Phosphors in White LEDsRequirements for Phosphors in White LEDsClassification of PhosphorsPhotoluminescent Properties of Traditional PhosphorsNitride Phosphors i

  18. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    Science.gov (United States)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  19. Formation and Structure of Boron Nitride Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Jiang ZHANG; Zongquan LI; Jin XU

    2005-01-01

    Boron nitride (BN) nanotubes were simply synthesized by heating well-mixed boric acid, urea and iron nitrate powders at 1000℃. A small amount of BN nanowires was also obtained in the resultants. The morphological and structural characters of the BN nanostructures were studied using transmission electron microscopy. Other novel BN nanostructures, such as Y-junction nanotubes and bamboo-like nanotubes, were simultaneously observed. The growth mechanism of the BN nanotubes was discussed briefly.

  20. Boron Nitride Nanosheets for Metal Protection

    OpenAIRE

    Li, Lu Hua; Xing, Tan; Chen, Ying; Jones, Rob

    2015-01-01

    Although the high impermeability of graphene makes it an excellent barrier to inhibit metal oxidation and corrosion, graphene can form a galvanic cell with the underlying metal that promotes corrosion of the metal in the long term. Boron nitride (BN) nanosheets which have a similar impermeability could be a better choice as protective barrier, because they are more thermally and chemically stable than graphene and, more importantly, do not cause galvanic corrosion due to their electrical insu...

  1. Anomalous thermal conductivity of monolayer boron nitride

    Science.gov (United States)

    Tabarraei, Alireza; Wang, Xiaonan

    2016-05-01

    In this paper, we use nonequilibrium molecular dynamics modeling to investigate the thermal properties of monolayer hexagonal boron nitride nanoribbons under uniaxial strain along their longitudinal axis. Our simulations predict that hexagonal boron nitride shows an anomalous thermal response to the applied uniaxial strain. Contrary to three dimensional materials, under uniaxial stretching, the thermal conductivity of boron nitride nanoribbons first increases rather than decreasing until it reaches its peak value and then starts decreasing. Under compressive strain, the thermal conductivity of monolayer boron nitride ribbons monolithically reduces rather than increasing. We use phonon spectrum and dispersion curves to investigate the mechanism responsible for the unexpected behavior. Our molecular dynamics modeling and density functional theory results show that application of longitudinal tensile strain leads to the reduction of the group velocities of longitudinal and transverse acoustic modes. Such a phonon softening mechanism acts to reduce the thermal conductivity of the nanoribbons. On the other hand, a significant increase in the group velocity (stiffening) of the flexural acoustic modes is observed, which counteracts the phonon softening effects of the longitudinal and transverse modes. The total thermal conductivity of the ribbons is a result of competition between these two mechanisms. At low tensile strain, the stiffening mechanism overcomes the softening mechanism which leads to an increase in the thermal conductivity. At higher tensile strain, the softening mechanism supersedes the stiffening and the thermal conductivity slightly reduces. Our simulations show that the decrease in the thermal conductivity under compressive strain is attributed to the formation of buckling defects which reduces the phonon mean free path.

  2. Silicon Nitride Antireflection Coatings for Photovoltaic Cells

    Science.gov (United States)

    Johnson, C.; Wydeven, T.; Donohoe, K.

    1984-01-01

    Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

  3. Nitride inclusions in titanium-containing high-nitrogen steel after solid-phase nitriding

    Science.gov (United States)

    Lysenkova, E. V.; Kadach, M. V.; Butskii, E. V.; Dorofievich, I. V.; Stomakhin, A. Ya.

    2015-09-01

    The principal possibility of production of sheet titanium-containing high-nitrogen steels without extreme harmful coarse nitride inclusions and their aggregates, which are characteristic of these compositions even at a relatively low (impurity) nitrogen content, is studied. To this end, the nitrogen content in the initial metal before its solidification is limited to the calculation level at which titanium nitrides are thermally unstable. Nitrogen is introduced in metal (08Cr18Ni12Ti steel) during its chemical thermal treatment in a nitrogen atmosphere at 1200°C. The nitrogen content in the finished metal is 0.4% (at 0.31% Ti). Studies in this direction are thought to be promising, since it is evident that the production of a metal of such a composition using the standard method of nitrogen introduction (in melt) is impossible. Scanning electron microscopy shows that titanium nitride particles in the finished metal are ≤0.5 μm in size.

  4. Heavy ion bombardment of silicates and nitrides

    International Nuclear Information System (INIS)

    Several silicates, including α-quartz, zirconium silicate, thorium silicate, LiAlSiO4, a silicate glass and several nitrides, α and β Si3N4, AlN, ZrN as well as Si2N2O and ThO2, have been irradiated by 1019 to 1021 Krypton (3 MeV) ions/m2. The damaged powders of original particle size less than 5 μm, have been examined by x-ray diffraction and electron microscope methods. The silicates and Si2N2O become non-crystalline by 10 x 1019 ions/m2. The particles change shape, extending and bloating under prolonged irradiations of the order of 100 x 1019 ions/m2. Silicate glass also undergoes this irradiation creep process. The nitrides and ThO2 behave quite differently and even at fluences of 200 x 1019 x ions/m-2 the powders remain crystalline, retaining relatively sharp edges to the particles without exhibiting irradiation creep. This difference in behavior can be related to the nature of the framework crystal structures, flexible for the silicates with variable bond angles, rigid for the nitrides with fixed bond angles. This may explain the behavior of radioactive minerals not found in a metamict condition. (author)

  5. Microscopic modeling of nitride intersubband absorbance

    Science.gov (United States)

    Montano, Ines; Allerman, A. A.; Wierer, J. J.; Moseley, M.; Skogen, E. J.; Tauke-Pedretti, A.; Vawter, G. A.

    III-nitride intersubband structures have recently attracted much interest because of their potential for a wide variety of applications ranging from electro-optical modulators to terahertz quantum cascade lasers. To overcome present simulation limitations we have developed a microscopic absorbance simulator for nitride intersubband devices. Our simulator calculates the band structure of nitride intersubband systems using a fully coupled 8x8 k.p Hamiltonian and determines the material response of a single period in a density-matrix-formalism by solving the Heisenberg equation including many-body and dephasing contributions. After calculating the polarization due to intersubband transitions in a single period, the resulting absorbance of a superlattice structure including radiative coupling between the different periods is determined using a non-local Green's-function formalism. As a result our simulator allows us to predict intersubband absorbance of superlattice structures with microscopically determined lineshapes and linewidths accounting for both many-body and correlation contributions. This work is funded by Sandia National Laboratories Laboratory Directed Research and Development program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin.

  6. Synthesis and high temperature XRD studies of tantalum nitride thin films prepared by reactive pulsed dc magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Elangovan, T. [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore-641 046 (India); Murugeshan, S. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore-641 046 (India); Kuppusami, P.; Khan, Shabhana; Sudha, C. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102 (India); Ganesan, V. [UGC-DAE CSR, Indore-452 017 (India); Divakar, R.; Mohandas, E. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102 (India)

    2011-06-02

    In the present work, the growth characteristics of tantalum nitride (TaN) thin films prepared on (1 0 0) Si substrates by reactive pulsed DC magnetron sputtering are investigated. XRD analyses indicated the presence of {alpha}-Ta and {beta}-Ta in the films deposited in pure argon atmosphere, while {beta}-TaN and fcc-TaN phases appeared for 2 sccm of nitrogen, and cubic TaN for 5-25 sccm of nitrogen in the sputtering gas mixture of argon and nitrogen at a substrate temperature of 773 K. The TaN films obtained with increasing substrate temperature and pulse width showed a change in the texture from [1 1 1] to [2 0 0] orientation. Atomic force microscopy (AFM) results indicated that the average surface roughness was low for films deposited in pure argon than for the films deposited in a mixed Ar + N{sub 2} atmosphere. Nanocrystalline phase of the deposited material was identified from the high-resolution transmission electron microscopy (HRTEM) images. X-ray photoelectron spectroscopy (XPS) core level spectra confirmed the formation of TaN phase. The high temperature X-ray diffraction analysis of the optimized TaN thin film was performed in the temperature range 298-1473 K. The lattice parameter of the TaN films was found to increase from 4.383 to 4.393 A on increasing the temperature from 298 to 823 K and it reduced to 4.345 A at 1473 K. The thermal expansion coefficient value was found to be negative for the TaN films.

  7. Development of compound layer of iron (carbo)nitrides during nitriding of steel

    DEFF Research Database (Denmark)

    Ratajski, J.; Tacikowski, J.; Somers, Marcel A.J.

    2003-01-01

    The composition and phase constitution of a compound layer developing during gaseous nitriding was investigated at 853 K for three commercial steels (AISI 120, 4340 and 1090) and Armco iron. The compound layers were characterised by light optical microscopy, X-ray diffraction and electron probe...... microanalysis. The formation of the compound layer occurs along two distinct sequences: alpha-gamma prime-epsilon and/or alpha(theta)-epsilon2-gamma prime-epsilon1. The preferred sequence depends mainly on the chemical composition of steel and on the nitriding potential....

  8. The effects of argon in the bioenergetics of the hamster and the rat

    Science.gov (United States)

    Tempel, G. E.; Musacchia, X. J.

    1974-01-01

    Oxygen consumption was examined in hamsters and rats exposed to normoxic mixtures of argon at 1 atm. In fasted and nonfasted animals, no marked change in O2 utilization was detectable at 22 C. However, at 7 C a significant decrease in oxygen consumption was observed where the animals were exposed in argon. The data are interpreted in terms of the greater thermal conductivity of nitrogen. The study was prompted by conflicting reports on the metabolic effects of argon and helium.

  9. Argon Laser Photoablation for Treating Benign Pigmented Conjunctival Nevi

    Science.gov (United States)

    Alsharif, Abdulrahman M.; Al-Gehedan, Saeed M.; Alasbali, Tariq; Alkuraya, Hisham S.; Lotfy, Nancy M.; Khandekar, Rajiv

    2016-01-01

    Purpose: To evaluate the outcomes of argon laser photoablation of benign conjunctival pigmented nevi with different clinical presentations. Patients and Methods: This interventional case series was conducted between July 2014 and January 2015. Patients presenting with benign conjunctival nevi were included. Data were collected on the clinical features at presentation, argon laser photoablation, and follow-up at 8 and 24 weeks. Postoperative photography allowed recording of the success of each case and the overall success rate. Complete removal of conjunctival pigments was considered an absolute success. Partial pigmentation requiring repeat laser treatment was considered a qualified success. Results: There were 14 eyes (four right eyes and ten left eyes) with benign pigmented conjunctival nevi. There were three males and eight females in the study sample. The median age was 36 (25% percentile: 26 years). Three patients had bilateral lesions. The nevi were located temporally in nine eyes, nasally in three eyes, and on the inferior bulbar conjunctiva in two eyes. The mean horizontal and vertical diameters of nevi were 5 ± 2 mm and 4 ± 2.7 mm, respectively. The mean follow-up period was 5 months. Following laser treatment, no eyes had subconjunctival hemorrhage, infection, scarring, neovascularization, recurrence, or corneal damage. The absolute success rate of laser ablation was 79%. Three eyes with elevated nevi had one to three sessions of laser ablation resulting in a qualified success rate of 100%. Conclusions: Argon laser ablation was a safe and effective treatment for the treatment of selective benign pigmented conjunctival nevi in Arab patients. PMID:27555708

  10. The abundances of neon, sulfur, and argon in planetary nebulae

    Science.gov (United States)

    Beck, S. C.; Lacy, J. H.; Townes, C. H.; Aller, L. H.; Geballe, T. R.; Baas, F.

    1981-01-01

    New infrared observations of Ne II, Ar III, and S IV are used in optical observations of other ionization states of the considered elements to evaluate the abundances of neon, argon, and sulfur in 18 planetary nebulae. Attention is also given to one or more of the infrared lines in 18 other nebulae. It is pointed out that S IV was detected in approximately 90% of the observed objects, while Ar III was found in about 80%, and Ne II in roughly one-third. It is noted that optical observations typically include only a limited region of the nebula, while the infrared measurements frequently involve integration over the entire nebular image.

  11. Ionization coefficients for argon in a micro-discharge

    International Nuclear Information System (INIS)

    Ionization coefficients are measured for electrons in a dc micro-discharge in argon from optical emission profiles. The micro-discharge is operated in the Townsend regime between two parallel-plate electrodes. Axial profiles of emission are obtained with sufficient resolution to provide spatial ionization coefficients. The measured coefficients agree very well with the data obtained from other sources, indicating the operation of the discharge in the Townsend regime and also that Townsend mechanisms do not need extension to describe such discharges. (paper)

  12. Kinetic modeling of the Townsend breakdown in argon

    Science.gov (United States)

    Macheret, S. O.; Shneider, M. N.

    2013-10-01

    Kinetic modeling of the Townsend breakdown in argon was performed in the "forward-back" approximation. The kinetic model was found to adequately describe the left branch of the Paschen curve, and the important role of ionization by fast ions and atoms near the cathode, as well as the increase in secondary emission coefficient in strong electric fields described in the literature, was confirmed. The modeling also showed that the electron energy distribution function develops a beam of high-energy electrons and that the runaway effect, i.e., the monotonic increase of the mean electron energy with the distance from the cathode, occurs at the left branch of the Paschen curve.

  13. Ionization coefficients for argon in a micro-discharge

    Science.gov (United States)

    Kuschel, Thomas; Stefanović, Ilija; Malović, Gordana; Marić, Dragana; Petrović, Zoran Lj

    2013-08-01

    Ionization coefficients are measured for electrons in a dc micro-discharge in argon from optical emission profiles. The micro-discharge is operated in the Townsend regime between two parallel-plate electrodes. Axial profiles of emission are obtained with sufficient resolution to provide spatial ionization coefficients. The measured coefficients agree very well with the data obtained from other sources, indicating the operation of the discharge in the Townsend regime and also that Townsend mechanisms do not need extension to describe such discharges.

  14. Diffusion coefficient of metal vapours into rare gases. Mercury - argon

    International Nuclear Information System (INIS)

    The source information is present as well as the results of analysis and integration of data on mutual diffusion coefficient (MDC) of mercury - argon mixture at Hg concentration → 0 in 300-2500 K temperature range. Reference data on MDC for metal - inert gas binary mixtures obtained on the base of complex analysis of various information, as it exemplified by Hg-Ar pair, can be used as a part of metrological support at calibration of devices for determination MDC of gas - metal vapors

  15. Electron drift velocity in argon-methane mixture

    International Nuclear Information System (INIS)

    Described are the results of a series of measurements of electron drift velocity taken with samples of chemically pure grade gas mixture of Ar-10% CH4 (N2222O<2 ppm). The measured drift velocity is plotted as a function of the ratio of electric field to pressure in the range from 0.05 to 0.8 V/cmxtorr. The measurements are reproducible only to within 4%. The results of numerical calculations employing the well-established argon elastic and methane elastic and inelastic cross sections are also included. The disagreement from the present experimental results, and from those obtained elsewhere, is rather puzzling

  16. High intensity, argon ion laser-jet photochemistry

    Science.gov (United States)

    Wilson, R. Marshall; Schnapp, Karlyn A.; Hannemann, Klaus; Ho, Douglas M.; Memarian, Hamid R.; Azadnia, Ardeshir; Pinhas, Allan R.; Figley, Timothy M.

    A new technique for the study of high intensity solution photochemistry has been developed. With this laser-jet technique, a high velocity microjet is irradiated with the focussed output of an argon ion laser. Under these extremely high intensity conditions, photochemically generated transient species with suitable absorption properties are excited further and produce relatively large amounts of photoproducts which are not observed under low intensity conditions. The application of this laser-jet technique in the study of the photochemistry of radicals, biradicals, photoenols and the higher excited states of carbonyl and polycyclic aromatic compounds is described.

  17. Optical fiber read-out for liquid argon scintillation light

    CERN Document Server

    Csáthy, J Janicskó; Kratz, J; Schönert, S; Wiesinger, Ch

    2016-01-01

    In this paper we describe the performance of a light detector for Ar scintillation light made of wavelength-shifting (WLS) fibers connected to Silicon-Photomultipliers (SiPM). The setup was conceived to be used as anti-Compton veto for high purity germanium (HPGe) detectors operated directly in liquid Argon (LAr). Background suppression efficiencies for different radioactive sources were measured in a test cryostat with about 800 kg LAr. This work was part of the R\\&D effort for the GERDA experiment.

  18. Study of a novel electromagnetic liquid argon calorimeter TGT

    International Nuclear Information System (INIS)

    The concept and the basic design of a fast, highly granular and compact electromagnetic liquid argon calorimeter are described. This novel calorimeter offers uniform energy response and constant energy resolution independent of the production angle of an impinging particle and of its impact position at the calorimeter. An example of a calorimeter with full rapidity coverage in an application in a collider detector is given. An important aspect of the concept is the electronics for fast signal processing matched to the short charge collection time. We report on the experience with the realization of a prototype calorimeter module and on its performance in a test beam exposure. 15 refs., 16 figs., 2 tabs

  19. Activation of copper by nitrogen and argon beams

    Energy Technology Data Exchange (ETDEWEB)

    Chetvertkova, Vera [IAP, Goethe-University, Frankfurt am Main (Germany); GSI Darmstadt (Germany); Mustafin, Edil; Strasik, Ivan [GSI Darmstadt (Germany); Belousov, Anton [TU Darmstadt (Germany); Latysheva, Ludmila; Sobolevsky, Nikolai [INR RAS, Moscow (Russian Federation); Ratzinger, Ulrich [IAP, Goethe-University, Frankfurt am Main (Germany)

    2012-07-01

    Monte Carlo transport codes are widely used for various purposes in nuclear physics, radiation protection, medical applications, accelerator design etc. Code verification by experiments is needed to be sure that the codes give accurate results. New data on the activation of copper by a nitrogen beam of 500 MeV/u is presented and compared with FLUKA and SHIELD simulation results. The activation of copper by a nitrogen beam is compared to activation by an argon beam and respective simulations. This gives a chance to see the accuracy of the codes at different projectile masses. Correspondences and discrepancies of calculations and experiments are discussed.

  20. Study of a Novel Concept for a Liquid Argon Calorimeter \

    CERN Multimedia

    2002-01-01

    % RD33 \\\\ \\\\ The development of a fast, highly granular and compact electromagnetic liquid argon calorimeter prototype is proposed as a generic R\\&D project for a novel concept of calorimetry in proton-proton and electron-positron collider detectors: the $^{\\prime$Thin Gap Turbine$^{\\prime}$ (TGT). The TGT calorimeter has a modular construction, is flexible in its longitudinal and transverse granularity, and offers a uniform energy response and resolution, independent of the production angle of incident particles. An important aspect of the project is the development of fast, radiation-hard front-end electronics which is operating in the cold.

  1. Activation of aluminum by argon: Experimental study and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Chetvertkova, V., E-mail: v.chetvertkova@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung Darmstadt, Planckstrasse 1, 64291 Darmstadt (Germany); J. W. Goethe-University Frankfurt am Main, IAP, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Strasik, I. [GSI Helmholtzzentrum fuer Schwerionenforschung Darmstadt, Planckstrasse 1, 64291 Darmstadt (Germany); J. W. Goethe-University Frankfurt am Main, IAP, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Belousov, A. [GSI Helmholtzzentrum fuer Schwerionenforschung Darmstadt, Planckstrasse 1, 64291 Darmstadt (Germany); Iwase, H. [High Energy Accelerator Research Organization, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Mokhov, N. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Mustafin, E. [GSI Helmholtzzentrum fuer Schwerionenforschung Darmstadt, Planckstrasse 1, 64291 Darmstadt (Germany); Latysheva, L. [Institute for Nuclear Research RAS, 117312 Moscow (Russian Federation); Pavlovic, M. [FEI STU, Ilkovicova 3, 812 19 Bratislava (Slovakia); Ratzinger, U. [J. W. Goethe-University Frankfurt am Main, IAP, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Sobolevsky, N. [Institute for Nuclear Research RAS, 117312 Moscow (Russian Federation)

    2011-06-15

    The paper presents the results of irradiation of aluminum targets by 430 and 500 MeV/u argon beams. Gamma-spectra were measured after the end of the irradiation in order to identify the induced nuclides as well as to determine their residual activity depth-profiles. The results of this experiment are compared with Monte Carlo simulations by FLUKA, GEANT4, MARS, PHITS and SHIELD-A codes. In case of a thin target, the agreement between the experiment and simulations is satisfactory, while in case of a thick target, some discrepancies are observed.

  2. Laser-induced vibrational dynamics of ozone in solid argon

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Amstrup, B.; Henriksen, Niels Engholm

    1997-01-01

    We consider the vibrational dynamics, induced by an intense infrared laser pulse, in an ozone molecule with isotopic substitution, that is, (OOO)-O-16-O-16-O-18 and compare the dynamics in the gas phase and in solid ar on. not perturbed by argon on a time-scale of a few picoseconds and selective...... bond-breaking in the molecule should be possible following the same laser control scheme as suggested in the gas phase. (C) 1997 Elsevier Science B.V....

  3. Electron transport in argon in crossed electric and magnetic fields

    Science.gov (United States)

    Ness; Makabe

    2000-09-01

    An investigation of electron transport in argon in the presence of crossed electric and magnetic fields is carried out over a wide range of values of electric and magnetic field strengths. Values of mean energy, ionization rate, drift velocity, and diffusion tensor are reported here. Two unexpected phenomena arise; for certain values of electric and magnetic field we find regions where the swarm mean energy decreases with increasing electric fields for a fixed magnetic field and regions where swarm mean energy increases with increasing magnetic field for a fixed electric field. PMID:11088933

  4. New amorphous interface for precipitate nitrides in steel

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson; Kadkhodazadeh, Shima; Grumsen, Flemming Bjerg;

    2014-01-01

    during electron beam exposure. The amorphous shells were observed around Ta- and Nb-based nitrides, which are considered to have a high interfacial energy with the ferrite matrix. They were not observed around V-based nitrides which have a Baker–Nutting relationship with low-misfit to the matrix....

  5. Synthesis of metal-nitrides using high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, C; Serghiou, G [University of Edinburgh, School of Engineering and Electronics, Kings Buildings, Mayfield Road, EH9 3JL UK (United Kingdom); Morniroli, J P [Laboratoire de Metallurgie Physique et Genie des Materiaux, UMR CNRS 8517, Universite des Sciences et Technologies de Lille et Ecole Nationale Superieure de Chimie de Lille, Cite Scientifique, 59655 Villeneuve d' Ascq Cedex (France); Frost, D J [Bayerisches Geoinstitut, Universitat Bayreuth, D-95440, Bayreuth (Germany)], E-mail: george.serghiou@ed.ac.uk

    2008-07-15

    Technologically, high density nitrides are showing promise for both ceramic and electronic applications. In a laser-heated diamond cell we prepare high density metal-nitrides by reaction of the nitrogen pressure medium with an elemental substrate. Two of our objectives are to develop criteria governing whether denser than ambient nitride phases will form, and to in particular establish the parameters required for synthesis in a multianvil press using elemental starting materials. We have already synthesized transition metal nitrides in a multianvil press using elemental starting materials, including hexagonal nickel nitride and alkali rhenium nitrides. Unlike previous metals, we also report that Cu does not form a nitride after heating with NaN{sub 3} at 2000 K and 20 GPa. Notably, Cu{sub 3}N is a semiconductor exhibiting weak directional bonds, whereas the immediately adjacent lower atomic number systems are metallic interstitial nitrides. We also briefly mention our work on processing high pressure and temperature recovered reaction products with focused ion beam methods for tailored characterization using electron microscopy.

  6. EXAFS investigation of low temperature nitrided stainless steel

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny;

    2008-01-01

    Low temperature nitrided stainless steel AISI 316 flakes were investigated with EXAFS and X-ray diffraction analysis. The stainless steel flakes were transformed into a mixture of nitrogen expanded austenite and nitride phases. Two treatments were carried out yielding different overall nitrogen...

  7. Composition and microhardness of CAE boron nitride films

    International Nuclear Information System (INIS)

    The paper deals with boron nitride produced by cathodic arc evaporation techniques.The films were applied on titanium and cemented carbide substrates. Their characterization was carried out using X-ray diffraction and Knoop microhardness tests. Demonstrated are the high properties of two-phase films, containing β (cubic) and γ (wurtzitic) modifications of boron nitride. (author). 7 refs., 1 fig., 3 tabs

  8. Epitaxial aluminum nitride tunnel barriers grown by nitridation with a plasma source

    NARCIS (Netherlands)

    Zijlstra, T.; Lodewijk, C.F.J.; Vercruyssen, N.; Tichelaar, F.D.; Loudkov, D.N.; Klapwijk, T.M.

    2007-01-01

    High critical current-density (10 to 420 kA/cm2) superconductor-insulator-superconductor tunnel junctions with aluminum nitride barriers have been realized using a remote nitrogen plasma from an inductively coupled plasma source operated in a pressure range of 10−3–10−1 mbar. We find a much better r

  9. Low Temperature Gaseous Nitriding of a Stainless Steel Containing Strong Nitride Formers

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    Low temperature thermochemical surface hardening of the precipitation hardening austenitic stainless steel A286 in solution treated state was investigated. A286 contains, besides high amounts of Cr, also substantial amounts of strong nitride formers as Ti, Al and V. It is shown that simultaneous...

  10. Facile Solid-State Synthesis Route to Metal Nitride Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Yinxiao DU; Ming LEI; Hui YANG

    2008-01-01

    By a facile and efficient solid-state reaction route using an organic reagent cyanamide (CN2H2) as a precursor with another one being metal oxides, we successfully synthesized seven technologically important metal nitrides including cubic VN, CrN, NbN, hexagonal GaN, AIN, BN, and WN at moderate temperatures. The experimental results show that cyanamide (CN2H2) is a powerfully reducing and nitridizing reagent and the metal oxides are completely converted into the corresponding nitride nanoparticles at lower temperatures than that reported in the conventional methods. It is found that CN2H2 can exhibit some interesting condensation processes, and the final products, highly active carbon nitride species, play a crucial role in the reducing and nitridizing processes.

  11. Safety Assessment of Boron Nitride as Used in Cosmetics.

    Science.gov (United States)

    Fiume, Monice M; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2015-01-01

    The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of boron nitride which functions in cosmetics as a slip modifier (ie, it has a lubricating effect). Boron nitride is an inorganic compound with a crystalline form that can be hexagonal, spherical, or cubic; the hexagonal form is presumed to be used in cosmetics. The highest reported concentration of use of boron nitride is 25% in eye shadow formulations. Although boron nitride nanotubes are produced, boron nitride is not listed as a nanomaterial used in cosmetic formulations. The Panel reviewed available chemistry, animal data, and clinical data and concluded that this ingredient is safe in the present practices of use and concentration in cosmetic formulations.

  12. Gaseous Nitriding Process of Surface Nanocrystallized (SNCed) Steel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The behavior of gaseous nitriding on the surface nanocrystallized (SNCed) steel was investigated. The mild steel discs were SNCed on one side by using the method of ultrasonic shot peening. The opposite side of the discs maintained the original coarse-grained condition. The gaseous nitriding was subsequently carried out at three different temperatures:460, 500 and 560℃. The compound layer growth and diffusion behavior were then studied. It was revealed that SNC pretreatment greatly enhances both diffusion coefficient D and surface reaction rate. As a result, nitriding time could be reduced to the half. It was also found that the growth of compound layer with nitriding time conformed with parabolic relationship from the start of nitriding process in the SNCed samples.

  13. Design of nitride semiconductors for solar energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Zakutayev, Andriy

    2016-01-01

    Nitride semiconductors are a promising class of materials for solar energy conversion applications, such as photovoltaic and photoelectrochemical cells. Nitrides can have better solar absorption and electrical transport properties than the more widely studied oxides, as well as the potential for better scalability than other pnictides or chalcogenides. In addition, nitrides are also relatively unexplored compared to other chemistries, so they provide a great opportunity for new materials discovery. This paper reviews the recent advances in the design of novel semiconducting nitrides for solar energy conversion technologies. Both binary and multinary nitrides are discussed, with a range of metal chemistries (Cu3N, ZnSnN2, Sn3N4, etc.) and crystal structures (delafossite, perovskite, spinel, etc.), including a brief overview of wurtzite III-N materials and devices. The current scientific challenges and promising future directions in the field are also highlighted.

  14. LArIAT: Liquid Argon In A Testbeam

    CERN Document Server

    Cavanna, F; Raaf, J; Rebel, B

    2014-01-01

    Liquid Argon Time Projection Chambers (LArTPCs) are ideal detectors for precision neutrino physics. These detectors, when located deep underground, can also be used for measurements of proton decay, and astrophysical neutrinos. The technology must be completely developed, up to very large mass scales, and fully mastered to construct and operate these detectors for this physics program. As part of an integrated plan of developing these detectors, accurate measurements in LArTPC of known particle species in the relevant energy ranges are now deemed as necessary. The LArIAT program aims to directly achieve these goals by deploying LArTPC detectors in a dedicated calibration test beam line at Fermilab. The set of measurements envisaged here are significant for both the short-baseline (SBN) and long-baseline (LBN) neutrino oscillation programs in the US, starting with MicroBooNE in the near term and with the adjoint near and far liquid argon detectors in the Booster beam line at Fermilab envisioned in the mid-term...

  15. A liquid argon scintillation veto for the GERDA experiment

    International Nuclear Information System (INIS)

    Gerda is an experiment to search for the neutrinoless double beta decay of 76Ge. Results of Phase I have been published in summer 2013. Currently Gerda is being upgraded to a second phase. To reach the aspired background index of ≤ 10-3 cts/(keV . kg . yr) for Phase II active background-suppression techniques will be applied, including an active liquid argon veto (LAr veto). It has been demonstrated by the LArGe test facility that the detection of argon scintillation light can be used to effectively suppress background events in the germanium, which simultaneously deposit energy in LAr. This talk focusses on the light instrumentation which is being installed in GERDA. Photomultiplier tubes (PMT) and wavelength-shifting fibers connected to silicon photomultipliers (SiPM) are combined to maximize the photoelectron-yield with respect to various background sources. Monte Carlo simulations have been performed to optimize the design for background suppression and low self-induced background. First results of the prototypes and the progress of installation are reported.

  16. A liquid argon scintillation veto for the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Wegmann, Anne [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Collaboration: GERDA-Collaboration

    2014-07-01

    Gerda is an experiment to search for the neutrinoless double beta decay of {sup 76}Ge. Results of Phase I have been published in summer 2013. Currently Gerda is being upgraded to a second phase. To reach the aspired background index of ≤ 10{sup -3} cts/(keV . kg . yr) for Phase II active background-suppression techniques will be applied, including an active liquid argon veto (LAr veto). It has been demonstrated by the LArGe test facility that the detection of argon scintillation light can be used to effectively suppress background events in the germanium, which simultaneously deposit energy in LAr. This talk focusses on the light instrumentation which is being installed in GERDA. Photomultiplier tubes (PMT) and wavelength-shifting fibers connected to silicon photomultipliers (SiPM) are combined to maximize the photoelectron-yield with respect to various background sources. Monte Carlo simulations have been performed to optimize the design for background suppression and low self-induced background. First results of the prototypes and the progress of installation are reported.

  17. Some transport properties in plasmas containing argon and fluorine

    Directory of Open Access Journals (Sweden)

    Novaković R.N.V.

    2003-01-01

    Full Text Available In this paper some results of numerical evaluation of transport coefficients in plasmas in the mixtures of argon and fluorine are presented. These transport characteristics are given in the function of the temperature for low pressures ranging from 0,1 kPa to 1,0 kPa and for low temperatures between 500 K and 5 000 K in argon plasmas with 20% and 30% of the fluorine added. It is assumed that the system is kept under constant pressure and that a corresponding state of local thermodynamical equilibrium (LTE is attained in it. The equilibrium plasma composition, necessary for the evaluations, was determined on the ground of the Saha equations for ionization processes and the law of mass action for the thermal dissociation of F2, combined with the charge conservation relation and the assumption that the pressure remained constant in the course of temperature variations. The ionization energy lowering, required in conjunction with the Saha equations, was obtained with the aid of a modified expression for the plasma Debye radius proposed previously. A previously derived expression for the modified Debye radius, offering the possibility to treat the plasmas considered as weakly non-ideal in the whole temperature range, is used. The cut-off at the Landau length rather than of the smallest of ionic radii is introduced. This alteration in the evaluation procedure brings different considerable changes in the final numerical results for the all relevant quantities.

  18. Compilation of electron collision excitation cross sections for neutro argon

    International Nuclear Information System (INIS)

    The present work presents a compilation and critical analysis of the available data on electron collision excitation cross sections for neutral Argon levels. This study includes: 1.- A detailed description in intermediate coupling for all the levels belonging the 20 configurations 3p''5 ns(n=4 to 12), np(n=4 to 8) and nd(n=3 to 8) of neutral Argon. 2.- Calculation of the electron collision excitation cross sections in Born and Born-Oppenheimer-Ochkur approximations for all the levels in the 14 configurations 3p''5 ns(n=4 to 7), np(n=4 to 7) and nd(n=3 to 8). 3.- Comparison and discussion of the compiled data. These are the experimental and theoretical values available from the literature, and those from this work. 4.- Analysis of the regularities and systematic behaviors in order to determine which values can be considered more reliable. It is show that the concept of one electron cross section results quite useful for this purpose. In some cases it has been possible to obtain in this way approximate analytical expressions interpolating the experimental data. 5.- All the experimental and theoretical values studied are graphically presented and compared. 6.- The last part of the work includes a listing of several general purpose programs for Atomic Physics calculations developed for this work. (Author)

  19. Elastic properties of liquid and solid argon in nanopores.

    Science.gov (United States)

    Schappert, Klaus; Pelster, Rolf

    2013-10-16

    We have measured sorption isotherms and determined the intrinsic longitudinal elastic modulus β(Ar,ads) of nanoconfined material via ultrasonic measurements combined with a special effective medium analysis. In the liquid regime the adsorbate only contributes to the measured effective properties when the pores are completely filled and the modulus is bulklike. At partial fillings its contribution is cancelled out by the high compressibility of the vapour phase. In contrast, at lower temperatures frozen argon as well as underlying liquid surface layers cause a linear increase of the effective longitudinal modulus upon filling. During sorption the contribution of the liquid surface layers near the pore wall β(Ar,surf) increases with the thickness of the solid layers reaching the bulk value β(Ar,liquid) only in the limit of complete pore filling. We interpret this effect as due to the gradual stiffening of the solid argon membrane. The measurements and their analysis show that longitudinal ultrasonic waves are well suited to the study of the elastic properties and liquid-solid phase transitions in porous systems. This method should also help to detect the influence of nanoconfinement on elastic properties in further research. PMID:24057946

  20. A chromium nitride/carbon nitride containing graphitic carbon nanocapsule hybrid as a Pt-free electrocatalyst for oxygen reduction.

    Science.gov (United States)

    Zhao, Lu; Wang, Lei; Yu, Peng; Zhao, Dongdong; Tian, Chungui; Feng, He; Ma, Jing; Fu, Honggang

    2015-08-11

    Chromium nitride nanoparticles supported on graphitic carbon nanocapsules containing carbon nitride (CrN/GC) have been synthesized by a solvothermal-assisted ion-exchange route. As a Pt-free catalyst, the CrN/GC hybrid exhibits superior activity, stability, methanol immunity and a dominant 4-electron pathway towards oxygen reduction reaction.

  1. Local effects of ECRH on argon transport at ASDEX upgrade

    International Nuclear Information System (INIS)

    Future deuterium-tritium magnetically confined fusion power plants will most probably rely an high-Z Plasma Facing Components (PFCs) such as tungsten. This choice is determined by the necessity of low erosion of the first wall materials (to guarantee a long lifetime of the wall components) and by the need to avoid the too high tritium wall retention of typical carbon based PFCs. The experience gathered at the ASDEX Upgrade (AUG) tokamak has demonstrated the possibility of reliable and high performance plasma operation with a full tungsten-coated first wall. The observed accumulation of tungsten which can lead to excessive radiation losses is mitigated with the use of Electron Cyclotron Resonance Heating (ECRH). Although this impurity control method is routinely performed at AUG, the underlying physics principles are still not clear. This thesis aims an providing further knowledge an the effects of ECRH an the transport of impurities inside the core plasma. The transport of argon has been therefore investigated in-depth in purely ECR heated L-mode (low-confinement) discharges. Studies an impurity transport in centrally ECR heated nitrogen-seeded H-mode (high-confinement) discharges have also been performed. To this scope, a new crystal X-ray spectrometer of the Johann type has been installed an AUG for argon concentration and ion temperature measurements. New methods for the experimental determination of the total argon density through the integrated use of this diagnostic and of the Soft X-Ray (SXR) diode arrays have been developed. This gives the possibility of evaluating the full profiles of the argon transport coefficients from the linear flux-gradient dependency of local argon density. In comparison to classical χ2-minimization methods, the approach proposed here delivers transport coefficients intrinsically independent of the modelling of periodic relaxation mechanisms such as those Lied to sawtooth MHD (Magneto-Hydro-Dynamic) activity. Moreover, the good

  2. Effect of Plasma Nitriding on the Performance of WC-Co Cutting Tools

    Science.gov (United States)

    Hamzaoglu, Ebru; Yilmaz, Safak; Gulmez, Turgut

    2011-04-01

    This paper presents the effect of nitriding process parameters on the cutting performance of WC-Co tools. The cutting performance was measured by CNC machining of GG25 cast iron parts. The hardness and phase composition of nitrided layer were determined for different plasma nitriding temperatures and times. The hardness of the nitrided layer increased at all plasma nitrided conditions investigated. However, the machining performance of the cutting inserts varied in the range between a 60% increase and a 40% decrease after plasma nitriding. The maximum number of machined parts was seen when the insert was nitrided at 600 °C-4 h and at 500 °C-4 h.

  3. Ballistic thermoelectric properties in boron nitride nanoribbons

    Science.gov (United States)

    Xie, Zhong-Xiang; Tang, Li-Ming; Pan, Chang-Ning; Chen, Qiao; Chen, Ke-Qiu

    2013-10-01

    Ballistic thermoelectric properties (TPs) in boron nitride nanoribbons (BNNRs) are studied using the nonequilibrium Green's function atomistic simulation of electron and phonon transport. A comparative analysis for TPs between BNNRs and graphene nanoribbons (GNRs) is made. Results show that the TPs of BNNRs are better than those of GNRs stemming from the higher power factor and smaller thermal conductance of BNNRs. With increasing the ribbon width, the maximum value of ZT (ZTmax) of BNNRs exhibits a transformation from the monotonic decrease to nonlinear increase. We also show that the lattice defect can enhance the ZTmax of these nanoribbons strongly depending on its positions and the edge shape.

  4. Low-dimensional boron nitride nanomaterials

    Directory of Open Access Journals (Sweden)

    Amir Pakdel

    2012-06-01

    Full Text Available In this review, a concise research history of low-dimensional boron nitride (BN nanomaterials followed by recent developments in their synthesis, morphology, properties, and applications are presented. Seventeen years after the initial synthesis of BN nanotubes, research on BN nanomaterials has developed far enough to establish them as one of the most promising inorganic nanosystems. In this regard, it is envisaged that the unique properties of low-dimensional BN systems, such as superb mechanical stiffness, high thermal conductivity, wide optical bandgap, strong ultraviolet emission, thermal stability and chemical inertness will play a key role in prospective developments.

  5. Nitride Semiconductors Handbook on Materials and Devices

    CERN Document Server

    Ruterana, Pierre; Neugebauer, Jörg

    2003-01-01

    Semiconductor components based on silicon have been used in a wide range of applications for some time now. These elemental semiconductors are now well researched and technologically well developed. In the meantime the focus has switched to a new group of materials: ceramic semiconductors based on nitrides are currently the subject of research due to their optical and electronic characteristics. They open up new industrial possibilities in the field of photosensors, as light sources or as electronic components. This collection of review articles provides a systematic and in-depth overview of t

  6. Magnesium doping of boron nitride nanotubes

    Science.gov (United States)

    Legg, Robert; Jordan, Kevin

    2015-06-16

    A method to fabricate boron nitride nanotubes incorporating magnesium diboride in their structure. In a first embodiment, magnesium wire is introduced into a reaction feed bundle during a BNNT fabrication process. In a second embodiment, magnesium in powder form is mixed into a nitrogen gas flow during the BNNT fabrication process. MgB.sub.2 yarn may be used for superconducting applications and, in that capacity, has considerably less susceptibility to stress and has considerably better thermal conductivity than these conventional materials when compared to both conventional low and high temperature superconducting materials.

  7. Method for exfoliation of hexagonal boron nitride

    Science.gov (United States)

    Lin, Yi (Inventor); Connell, John W. (Inventor)

    2012-01-01

    A new method is disclosed for the exfoliation of hexagonal boron nitride into mono- and few-layered nanosheets (or nanoplatelets, nanomesh, nanoribbons). The method does not necessarily require high temperature or vacuum, but uses commercially available h-BN powders (or those derived from these materials, bulk crystals) and only requires wet chemical processing. The method is facile, cost efficient, and scalable. The resultant exfoliated h-BN is dispersible in an organic solvent or water thus amenable for solution processing for unique microelectronic or composite applications.

  8. Novel nanoscroll structures from carbon nitride layers.

    Science.gov (United States)

    Perim, Eric; Galvao, Douglas S

    2014-08-01

    Nanoscrolls (papyrus-like nanostructures) are very attractive structures for a variety of applications, owing to their tunable diameter and large accessible surface area. They have been successfully synthesized from different materials. In this work, we investigate, through fully atomistic molecular dynamics simulations, the dynamics of scroll formation for a series of graphene-like carbon nitride (CN) two-dimensional systems: g-CN, triazine-based g-C3 N4 , and heptazine-based g-C3 N4 . Our results show that stable nanoscrolls can be formed for each of these structures. Possible synthetic routes to produce these nanostructures are also addressed. PMID:24819427

  9. Boron nitride nanomaterials for thermal management applications.

    Science.gov (United States)

    Meziani, Mohammed J; Song, Wei-Li; Wang, Ping; Lu, Fushen; Hou, Zhiling; Anderson, Ankoma; Maimaiti, Halidan; Sun, Ya-Ping

    2015-05-18

    Hexagonal boron nitride nanosheets (BNNs) are analogous to their two-dimensional carbon counterparts in many materials properties, in particular, ultrahigh thermal conductivity, but also offer some unique attributes, including being electrically insulating, high thermal stability, chemical and oxidation resistance, low color, and high mechanical strength. Significant recent advances in the production of BNNs, understanding of their properties, and the development of polymeric nanocomposites with BNNs for thermally conductive yet electrically insulating materials and systems are highlighted herein. Major opportunities and challenges for further studies in this rapidly advancing field are also discussed. PMID:25652360

  10. Ab Initio Study on Hypothetical Silver Nitride

    Institute of Scientific and Technical Information of China (English)

    DELIGOZ Engin; COLAKOGLU Kemal; CIFTCI Yasemin Oztekin

    2008-01-01

    We perform the ab initio calculations based on norm-conserving pseudopotentials and density functional theory to investigate the structural, elastic, and thermodynamical properties for silver nitride (AgN) compound that is a member of the 4d transition metal group and has not been synthesized yet. The obtained results are compared with the other available theoretical data, and the agreement is, generally, quite good. We also present the pressure-dependent behaviour of some mechanical and thermodynamical properties for the same compounds.

  11. Ful distil ation argon producing crud argon column on operating experience%全精馏制氩粗氩塔操作经验浅谈

    Institute of Scientific and Technical Information of China (English)

    马光显

    2015-01-01

    This paper briefly introduces the ful distil ation argon recovery process in the crude argon column in air separation system of cooling,heating and put some matters needing attention in use.%简要介绍了全精馏制氩过程中粗氩塔在空分系统降温、升温及投用中的一些注意事项。

  12. Ammonia Decomposition over Bimetallic Nitrides Supported on γ-Al2O3

    Institute of Scientific and Technical Information of China (English)

    Chun Shan LU; Xiao Nian LI; Yi Feng ZHU; Hua Zhang LIU; Chun Hui ZHOU

    2004-01-01

    A series of monometallic nitrides and bimetallic nitrides were prepared by temperature-programmed reaction with NH3. The effects of Co, Ni and Fe additives and the synergic action between Fe, Co, Ni and Mo on the ammonia decomposition activity were investigated. TPR-MS, XRD were also carried out to obtain better insight into the structure of the bimetallic nitride. The results of ammonia decomposition activity show that bimetallic nitrides are more active than monometallic nitrides or bimetallic oxides.

  13. Hard and low friction nitride coatings and methods for forming the same

    Science.gov (United States)

    Erdemir, Ali; Urgen, Mustafa; Cakir, Ali Fuat; Eryilmaz, Osman Levent; Kazmanli, Kursat; Keles, Ozgul

    2007-05-01

    An improved coating material possessing super-hard and low friction properties and a method for forming the same. The improved coating material includes the use of a noble metal or soft metal homogeneously distributed within a hard nitride material. The addition of small amounts of such metals into nitrides such as molybdenum nitride, titanium nitride, and chromium nitride results in as much as increasing of the hardness of the material as well as decreasing the friction coefficient and increasing the oxidation resistance.

  14. Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol

    Science.gov (United States)

    Sun, Wen-Ting; Li, Guo; Li, He-Ping; Bao, Cheng-Yu; Wang, Hua-Bo; Zeng, Shi; Gao, Xing; Luo, Hui-Ying

    2007-06-01

    Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure α-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images.

  15. First measurements with ARGONTUBE, a 5 m long drift Liquid Argon TPC

    International Nuclear Information System (INIS)

    The Liquid Argon Time Projection Chamber (LAr TPC) technique is a promising technology for future neutrino detectors. At LHEP of the University of Bern (Switzerland), an R and D program towards large detectors are on-going. The main goal is to show the feasibility of long drift paths over many meters. Therefore, a liquid Argon TPC with 5 m of drift distance was constructed. Many other aspects of the liquid Argon TPC technology are also investigated, such as a new device to generate high voltage in liquid Argon (Greinacher circuit), a recirculation filtering system and the multi-photon ionization of liquid Argon with a UV laser. Two detectors are built: a medium size prototype for specific detector technology studies, and ARGONTUBE, a 5 m long device

  16. Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol

    International Nuclear Information System (INIS)

    Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure α-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images

  17. First measurement of the ionization yield of nuclear recoils in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, T. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sangiorgio, Samuele [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Bernstein, A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Foxe, Michael P. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Hagmann, Chris [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Jovanovic, Igor [Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical and Nuclear Engineering; Kazkaz, K. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Mozin, Vladimir V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Norman, E. B. [Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering; Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pereverzev, S. V. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Rebassoo, Finn O. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sorensen, Peter F. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

    2014-05-01

    Liquid phase argon has long been used as a target medium for particle detection via scintillation light. Recently there has been considerable interest in direct detection of both hypothetical darkmatter particles and coherent elastic neutrino nucleus scattering. These as-yet unobserved neutral particle interactions are expected to result in a recoiling argon atom O(keV), generally referred to in the literature as a nuclear recoil. This prompts the question of the available electromagnetic signal in a liquid argon detector. In this Letter we report the first measurement of the ionization yield (Qy), detected electrons per unit energy, resulting from nuclear recoils in liquid argon, measured at 6.7 keV. This is also the lowest energy measurement of nuclear recoils in liquid argon.

  18. Management of Liver Cancer Argon-helium Knife Therapy with Functional Computer Tomography Perfusion Imaging.

    Science.gov (United States)

    Wang, Hongbo; Shu, Shengjie; Li, Jinping; Jiang, Huijie

    2016-02-01

    The objective of this study was to observe the change in blood perfusion of liver cancer following argon-helium knife treatment with functional computer tomography perfusion imaging. Twenty-seven patients with primary liver cancer treated with argon-helium knife and were included in this study. Plain computer tomography (CT) and computer tomography perfusion (CTP) imaging were conducted in all patients before and after treatment. Perfusion parameters including blood flows, blood volume, hepatic artery perfusion fraction, hepatic artery perfusion, and hepatic portal venous perfusion were used for evaluating therapeutic effect. All parameters in liver cancer were significantly decreased after argon-helium knife treatment (p liver tissue, but other parameters kept constant. CT perfusion imaging is able to detect decrease in blood perfusion of liver cancer post-argon-helium knife therapy. Therefore, CTP imaging would play an important role for liver cancer management followed argon-helium knife therapy.

  19. Investigation of surface properties of high temperature nitrided titanium alloys

    Directory of Open Access Journals (Sweden)

    E. Koyuncu

    2009-12-01

    Full Text Available Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys.Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, X-Ray diffraction and Vickers hardness.Findings: Two layers were determined by optic inspection on the samples that were called the compound and diffusion layers. Compound layer contain TiN and Ti2N nitrides, XRD results support in this formations. Maximum hardness was obtained at 10h treatment time and 1000°C treatment temperature. Micro hardness tests showed that hardness properties of the nitrided samples depend on treatment time and temperature.Practical implications: Titanium and its alloys have very attractive properties for many industries. But using of titanium and its alloys is of very low in mechanical engineering applications because of poor tribological properties.Originality/value: The nitriding of titanium alloy surfaces using plasma processes has already reached the industrial application stage in the biomedical field.

  20. Characterization of plasma nitrided layers produced on sintered iron

    Directory of Open Access Journals (Sweden)

    Marcos Alves Fontes

    2014-07-01

    Full Text Available Plasma nitriding is a thermo-physical-chemical treatment process, which promotes surface hardening, caused by interstitial diffusion of atomic nitrogen into metallic alloys. In this work, this process was employed in the surface modification of a sintered ferrous alloy. Scanning electron microscopy (SEM, X-ray diffraction (XRD analyses, and wear and microhardness tests were performed on the samples submitted to ferrox treatment and plasma nitriding carried out under different conditions of time and temperature. The results showed that the nitride layer thickness is higher for all nitrided samples than for ferrox treated samples, and this layer thickness increases with nitriding time and temperature, and temperature is a more significant variable. The XRD analysis showed that the nitrided layer, for all samples, near the surface consists in a mixture of γ′-Fe4N and ɛ-Fe3N phases. Both wear resistance and microhardness increase with nitriding time and temperature, and temperature influences both the characteristics the most.

  1. Solvothermal synthesis of crystalline carbon nitrides

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A solvothermal reaction of anhydrous C3N3Cl3 and Li3N using benzene as the solvent has been carried out to prepare crystalline carbon nitrides successfully at 350℃ and 5-6 MPa. X-ray diffraction (XRD) indicated that the major part of our brown sample was mainly composed of α-C3N4 and β-C3N4 with lattice parameters of a = 0. 65 nm, c = 0.47 nm for α-C3N4 and a = 0.644 nm, c = 0. 246 nm for β-C3N4, which match the latest ab-initio calculations quite well. The N/C ratio in the powder is about 0.66. The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses suggested the presence of both single and double carbon-nitrogen bonds. The kinetics effects of our solvothermal reaction to prepare crystalline carbon nitrides are also discussed chiefly.

  2. Development of membrane cryostats for large liquid argon neutrino detectors

    CERN Document Server

    Montanari, D; Gendotti, A; Geynisman, M; Hentschel, S; Loew, T; Mladenov, D; Montanari, C; Murphy, S; Nessi, M; Norris, B; Noto, F; Rubbia, A; Sharma, R; Smargianaki, D; Stewart, J; Vignoli, C; Wilson, P; Wu, S

    2015-01-01

    A new collaboration is being formed to develop a multi-kiloton Long-Baseline neutrino experiment that will be located at the Surf Underground Research Facility (SURF) in Lead, SD. In the present design, the detector will be located inside cryostats filled with 68,400 ton of ultrapure liquid argon (less than 100 parts per trillion of oxygen equivalent contamination). To qualify the membrane technology for future very large-scale and underground implementations, a strong prototyping effort is ongoing: several smaller detectors of growing size with associated cryostats and cryogenic systems will be designed and built at Fermilab and CERN. They will take physics data and test different detector elements, filtration systems, design options and installation procedures. In addition, a 35 ton prototype is already operational at Fermilab and will take data with single-phase detector in early 2016. After the prototyping phase, the multi-kton detector will be constructed. After commissioning, it will detect and study ne...

  3. Fluorescence Spectrum of SiO in an Argon Matrix

    Science.gov (United States)

    Scullman, R.; Hormes, J.; Schroeder, W.; Wiggenhauser, H.

    1987-04-01

    Fluorescence from SiO matrix isolated in argon has been investigated in the wavelength region 120-300 nm. Fluorescence emission spectra from the valence states, A1Π, E1Σ+ and G1Π, revealed that nearly all radiation comes from one channel at 305 nm, which was analysed as originating from the b3Π-X1Σ+ transition. Contrary to the A1Π and G1Π states, the E1Σ+ state also decays radiatively, although weakly, through two other channels situated in the vicinity of 305 nm. These two channels were believed to originate from the a3Σ+-X1Σ+ and e3Σ--X1Σ+ transitions.

  4. Electron Neutrino Classification in Liquid Argon Time Projection Chamber Detector

    CERN Document Server

    Płoński, Piotr; Sulej, Robert; Zaremba, Krzysztof

    2015-01-01

    Neutrinos are one of the least known elementary particles. The detection of neutrinos is an extremely difficult task since they are affected only by weak sub-atomic force or gravity. Therefore large detectors are constructed to reveal neutrino's properties. Among them the Liquid Argon Time Projection Chamber (LAr-TPC) detectors provide excellent imaging and particle identification ability for studying neutrinos. The computerized methods for automatic reconstruction and identification of particles are needed to fully exploit the potential of the LAr-TPC technique. Herein, the novel method for electron neutrino classification is presented. The method constructs a feature descriptor from images of observed event. It characterizes the signal distribution propagated from vertex of interest, where the particle interacts with the detector medium. The classifier is learned with a constructed feature descriptor to decide whether the images represent the electron neutrino or cascade produced by photons. The proposed ap...

  5. Large area liquid argon detectors for interrogation systems

    Energy Technology Data Exchange (ETDEWEB)

    Gary, Charles; Kane, Steve; Firestone, Murray I.; Smith, Gregory [Adelphi Technology LLC, Purdue Technology Center, 5225 Exploration Drive, Indianapolis, IN 46241 (United States); Gozani, Tsahi; Brown, Craig; Kwong, John; King, Michael J. [Rapiscan Laboratories, 520 Almanor Avenue, Sunnyvale, CA 94085 (United States); Nikkel, James A.; McKinsey, Dan [Physics Department, Yale University, New Haven, CT 06520 (United States)

    2013-04-19

    Measurements of the efficiency, pulse shape, and energy and time resolution of liquid argon (LAr) detectors are presented. Liquefied noble gas-based (LNbG) detectors have been developed for the detection of dark matter and neutrinoless double-beta decay. However, the same qualities that make LNbG detectors ideal for these applications, namely their size, cost, efficiency, pulse shape discrimination and resolution, make them promising for portal screening and the detection of Special Nuclear Materials (SNM). Two 18-liter prototype detectors were designed, fabricated, and tested, one with pure LAr and the other doped with liquid Xe (LArXe). The LArXe detector presented the better time and energy resolution of 3.3 ns and 20% at 662 KeV, respectively. The total efficiency of the detector was measured to be 35% with 4.5% of the total photons detected in the photopeak.

  6. Argon plasma coagulation for treatment of hemorrhagic radiation gastroduodenitis

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Shu-Ji; Aoyama, Nobuo; Shirasaka, Daisuke; Inoue, Takashi; Kuroda, Kohei; Ebara, Shigeyuki; Tamura, Takao; Miyamoto, Masaki; Kasuga, Masato [Kobe Univ. (Japan). Graduate School of Medicine

    2002-01-01

    A 79-year-old man who had received radiotherapy for portal vein thrombosis due to hepatocellular carcinoma (HCC) 5 months earlier, showed progressive anemia and melena. Endoscopy on admission revealed diffuse bleeding from multiple telangiectasias on the anterior wall of the antrum and bulbus. We treated this patient with a new non-contact hemostatic method: the argon plasma coagulator (APC). The melena stopped after the first session and the hemoglobin level remained stable for 7 months. No delayed complications have been observed. Gastrointestinal bleeding from chronic radiation gastroduodenitis is rarely reported compared with radiation proctitis. This case demonstrates that APC is effective for hemostasis of diffuse bleeding from radiation gastroduodenitis, just as for radiation protitis. (author)

  7. Line ratio diagnostics in helium and helium seeded argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Boivin, R F [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Loch, S D [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Ballance, C P [Physics Department, Rollins College, White Park, FL 32789 (United States); Branscomb, D [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Pindzola, M S [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States)

    2007-08-15

    We investigate the potential use of line ratio diagnostics to evaluate electron temperature in either helium or helium seeded argon plasmas. Plasmas are produced in a helicon plasma source. A rf compensated Langmuir probe is used to measure both the electron temperature and plasma density while a spectrometer is used to measure He I line intensities from the plasma. For all plasma densities where the electron temperature remains at 5 {+-} 1 eV, three He line ratios are measured. Each experimental ratio is compared with the prediction of three different collisional radiative models. One of these models makes uses of recent R-matrix with pseudo-states calculations for collisional rate coefficients. A discussion related to the different observations and model predictions is presented.

  8. Photodegradation Mechanisms of Tetraphenyl Butadiene Coatings for Liquid Argon Detectors

    CERN Document Server

    Jones, B J P; Conrad, J M; Pla-Dalmau, A

    2013-01-01

    We report on studies of degradation mechanisms of tetraphenyl butadiene (TPB) coatings of the type used in neutrino and dark matter liquid argon experiments. Using gas chromatography coupled to mass spectrometry we have detected the ultraviolet-blocking impurity benzophenone (BP). We monitored the drop in performance and increase of benzophenone concentration in TPB plates with exposure to ultraviolet (UV) light, and demonstrate the correlation between these two variables. Based on the presence and initially exponential increase in the concentration of benzophenone observed, we propose that TPB degradation is a free radical-mediated photooxidation reaction, which is subsequently confirmed by displaying delayed degradation using a free radical inhibitor. Finally we show that the performance of wavelength-shifting coatings of the type envisioned for the LBNE experiment can be improved by 10-20%, with significantly delayed UV degradation, by using a 20% admixture of 4-tert-Butylcatechol.

  9. Kinetic modeling of the Townsend breakdown in argon

    Energy Technology Data Exchange (ETDEWEB)

    Macheret, S. O.; Shneider, M. N. [Department of Mechanical and Aerospace Engineering, Princeton University, D-414 Engineering Quadrangle, Princeton, New Jersey 08544 (United States)

    2013-10-15

    Kinetic modeling of the Townsend breakdown in argon was performed in the “forward-back” approximation. The kinetic model was found to adequately describe the left branch of the Paschen curve, and the important role of ionization by fast ions and atoms near the cathode, as well as the increase in secondary emission coefficient in strong electric fields described in the literature, was confirmed. The modeling also showed that the electron energy distribution function develops a beam of high-energy electrons and that the runaway effect, i.e., the monotonic increase of the mean electron energy with the distance from the cathode, occurs at the left branch of the Paschen curve.

  10. Uranium (III) precipitation in molten chloride by wet argon sparging

    Science.gov (United States)

    Vigier, Jean-François; Laplace, Annabelle; Renard, Catherine; Miguirditchian, Manuel; Abraham, Francis

    2016-06-01

    In the context of pyrochemical processes for nuclear fuel treatment, the precipitation of uranium (III) in molten salt LiCl-CaCl2 (30-70 mol%) at 705 °C is studied. First, this molten chloride is characterized with the determination of the water dissociation constant. With a value of 10-4.0, the salt has oxoacid properties. Then, the uranium (III) precipitation using wet argon sparging is studied. The salt is prepared using UCl3 precursor. At the end of the precipitation, the salt is totally free of solubilized uranium. The main part is converted into UO2 powder but some uranium is lost during the process due to the volatility of uranium chloride. The main impurity of the resulting powder is calcium. The consequences of oxidative and reductive conditions on precipitation are studied. Finally, coprecipitation of uranium (III) and neodymium (III) is studied, showing a higher sensitivity of uranium (III) than neodymium (III) to precipitation.

  11. The readout driver (ROD) for the ATLAS liquid argon calorimeters

    Science.gov (United States)

    Efthymiopoulos, Ilias

    2001-04-01

    The Readout Driver (ROD) for the Liquid Argon calorimeter of the ATLAS detector is described. Each ROD module receives triggered data from 256 calorimeter cells via two fiber-optics 1.28 Gbit/s links with a 100 kHz event rate (25 kbit/event). Its principal function is to determine the precise energy and timing of the signal from discrete samples of the waveform, taken each period of the LHC clock (25 ns). In addition, it checks, histograms, and formats the digital data stream. A demonstrator system, consisting of a motherboard and several daughter-board processing units (PUs) was constructed and is currently used for tests in the lab. The design of this prototype board is presented here. The board offers maximum modularity and allows the development and testing of different PU designs based on today's leading integer and floating point DSPs.

  12. Characterization of SF6/Argon Plasmas for Microelectronics Applications; TOPICAL

    International Nuclear Information System (INIS)

    This report documents measurements in inductively driven plasmas containing SF(sub 6)/Argon gas mixtures. The data in this report is presented in a series of appendices with a minimum of interpretation. During the course of this work we investigated: the electron and negative ion density using microwave interferometry and laser photodetachment; the optical emission; plasma species using mass spectrometry, and the ion energy distributions at the surface of the rf biased electrode in several configurations. The goal of this work was to assemble a consistent set of data to understand the important chemical mechanisms in SF(sub 6) based processing of materials and to validate models of the gas and surface processes

  13. Photodegradation mechanisms of tetraphenyl butadiene coatings for liquid argon detectors

    Science.gov (United States)

    Jones, B. J. P.; VanGemert, J. K.; Conrad, J. M.; Pla-Dalmau, A.

    2013-01-01

    We report on studies of degradation mechanisms of tetraphenyl butadiene (TPB) coatings of the type used in neutrino and dark matter liquid argon experiments. Using gas chromatography coupled to mass spectrometry we have detected the ultraviolet-blocking impurity benzophenone. We monitored the drop in performance and increase of benzophenone concentration in TPB plates with exposure to ultraviolet (UV) light, and demonstrate the correlation between these two variables. Based on the presence and initially exponential increase in the concentration of benzophenone observed, we propose that TPB degradation is a free radical-mediated photooxidation reaction, which is subsequently confirmed by displaying delayed degradation using a free radical inhibitor. Finally we show that the performance of wavelength-shifting coatings of the type envisioned for the LBNE experiment can be improved by 10-20%, with significantly delayed UV degradation, by using a 20% admixture of 4-tert-Butylcatechol.

  14. Liquid Argon Cryogenic Detector Calibration by Inelastic Scattering of Neutrons

    CERN Document Server

    Polosatkin, Sergey; Dolgov, Alexander

    2014-01-01

    A method for calibration of cryogenic liquid argon detector response to recoils with certain energy -8.2 keV - is proposed. The method utilizes a process of inelastic scattering of monoenergetic neutrons produced by fusion DD neutron generator. Features of kinematics of inelastic scattering cause sufficient (forty times) increase in count rate of useful events relative to traditional scheme exploited elastic scattering with the same recoil energy and compatible energy resolution. The benefits of the proposed scheme of calibration most well implemented with the use of tagged neutron generator as a neutron source that allows to eliminate background originated from casual coincidence of signals on cryogenic detector and additional detector of scattered neutrons.

  15. The liquid argon TPC for the ICARUS experiment

    CERN Document Server

    Arneodo, F

    1997-01-01

    The ICARUS project aims at the realisation of a large liquid argon TPC to be run at the Underground Laboratories of Gran Sasso in Italy. An intense R&D; activity has put on firm grounds this new detector technology and experimentally confirmed its feasibility on a few ton scale. Based on these solid achievements, the collaboration is now confident of being able to build and safely operate a multi-kton detector. The reseach program of the experiment involves the systematic study of a wide spectrum of physical phenomena covering many orders of magnitude in the energy deposited in the detector: from the few MeV of solar neutrino interactions, to the about one GeV of the proton decay and atmospheric neutrinos, up to the higher energies of neutrinos from accelerators.

  16. Response Uniformity of the ATLAS Liquid Argon Electromagnetic Calorimeter

    CERN Document Server

    Aharrouche, M; Di Ciaccio, L; El Kacimi, M; Gaumer, O; Gouanère, M; Goujdami, D; Lafaye, R; Laplace, S; Le Maner, C; Neukermans, L; Perrodo, P; Poggioli, L; Prieur, D; Przysiezniak, H; Sauvage, G; Wingerter-Seez, I; Zitoun, R; Lanni, F; Lü, L; Ma, H; Rajagopalan, S; Takai, H; Belymam, A; Benchekroun, D; Hakimi, M; Hoummada, A; Gao, Y; Stroynowsk, R; Aleksa, M; Carli, T; Fassnacht, P; Gianotti, F; Hervás, L; Lampl, W; Collot, J; Hostachy, J Y; Ledroit-Guillon, F; Malek, F; Martin, P; Viret, S; Leltchouk, M; Parsons, J A; Simion, S; Barreiro, F; Del Peso, J; Labarga, L; Oliver, C; Rodier, S; Barrillon, P; Benchouk, C; Djama, F; Hubaut, F; Monnier, E; Pralavorio, P; Sauvage, D; Serfon, C; Tisserant, S; Tóth, J; Banfi, D; Carminati, L; Cavalli, D; Costa, G; Delmastro, M; Fanti, M; Mandell, L; Mazzanti, M; Tartarelli, F; Kotov, K; Maslennikov, A; Pospelov, G; Tikhonov, Yu; Bourdarios, C; Fayard, L; Fournier, D; Iconomidou-Fayard, L; Kado, M; Parrour, G; Puzo, P; Rousseau, D; Sacco, R; Serin, L; Unal, G; Zerwas, D; Dekhissi, B; Derkaoui, J; EL Kharrim, A; Maaroufi, F; Cleland, W; Lacour, D; Laforge, B; Nikolic-Audit, I; Schwemling, Ph; Ghazlane, H; Cherkaoui El Moursli, R; Idrissi Fakhr-Eddine, A; Boonekamp, M; Kerschen, N; Mansoulié, B; Meyer, P; Schwindlingy, J; Lund-Jensen, B

    2007-01-01

    The construction of the ATLAS electromagnetic liquid argon calorimeter modules is completed and all the modules are assembled and inserted in the cryostats. During the production period four barrel and three endcap modules were exposed to test beams in order to assess their performance, ascertain the production quality and reproducibility, and to scrutinize the complete energy reconstruction chain from the readout and calibration electronics to the signal and energy reconstruction. It was also possible to check the full Monte Carlo simulation of the calorimeter. The analysis of the uniformity, resolution and extraction of constant term is presented. Typical non-uniformities of 0.5% and typical global constant terms of 0.6% are measured for the barrel and end-cap modules.

  17. A Thermodynamic Model for Argon Plasma Kernel Formation

    Directory of Open Access Journals (Sweden)

    James Keck

    2010-11-01

    Full Text Available Plasma kernel formation of argon is studied experimentally and theoretically. The experiments have been performed in a constant volume cylindrical vessel located in a shadowgraph system. The experiments have been done in constant pressure. The energy of plasma is supplied by an ignition system through two electrodes located in the vessel. The experiments have been done with two different spark energies to study the effect of input energy on kernel growth and its properties. A thermodynamic model employing mass and energy balance was developed to predict the experimental data. The agreement between experiments and model prediction is very good. The effect of various parameters such as initial temperature, initial radius of the kernel, and the radiation energy loss have been investigated and it has been concluded that initial condition is very important on formation and expansion of the kernel.

  18. The readout driver (ROD) for the ATLAS liquid argon calorimeters

    CERN Document Server

    Efthymiopoulos, I

    2001-01-01

    The Readout Driver (ROD) for the Liquid Argon calorimeter of the ATLAS detector is described. Each ROD module receives triggered data from 256 calorimeter cells via two fiber-optics 1.28 Gbit/s links with a 100 kHz event rate (25 kbit/event). Its principal function is to determine the precise energy and timing of the signal from discrete samples of the waveform, taken each period of the LHC clock (25 ns). In addition, it checks, histograms, and formats the digital data stream. A demonstrator system, consisting of a motherboard and several daughter-board processing units (PUs) was constructed and is currently used for tests in the lab. The design of this prototype board is presented here. The board offers maximum modularity and allows the development and testing of different PU designs based on today's leading integer and floating point DSPs. (3 refs).

  19. Attosecond Coherent Control of Single and Double Photoionization in Argon.

    Science.gov (United States)

    Hogle, C W; Tong, X M; Martin, L; Murnane, M M; Kapteyn, H C; Ranitovic, P

    2015-10-23

    Ultrafast high harmonic beams provide new opportunities for coherently controlling excitation and ionization processes in atoms, molecules, and materials on attosecond time scales by employing multiphoton two-pathway electron-wave-packet quantum interferences. Here we use spectrally tailored and frequency tuned vacuum and extreme ultraviolet harmonic combs, together with two phase-locked infrared laser fields, to show how the total single and double photoionization yields of argon can be coherently modulated by controlling the relative phases of both optical and electronic-wave-packet quantum interferences. This Letter is the first to apply quantum control techniques to double photoionization, which is a fundamental process where a single, high-energy photon ionizes two electrons simultaneously from an atom. PMID:26551112

  20. Dynamic resonances and tunnelling in the multiphoton ionization of argon

    International Nuclear Information System (INIS)

    We present results of wavepacket simulations for multiphoton ionization in argon. A single active electron model is applied to estimate the single-electron ionization rates and photoelectron energy distributions for λ = 390 nm light with intensities up to I = 2 x 1014 W cm-2. The multiphoton ionization rates are compared with R-matrix Floquet calculations and found to be in very good agreement. The photoelectron energy distribution is used to study the nature of ionization at the higher intensities. Our results are consistent with recent calculations and experiments which show the imprint of the tunnelling process in the multiphoton regime. For few-cycle intense pulses, we find that the strong modulation of intensity and increased bandwidth leads to dynamic mixing of the 3d and 5s resonances.

  1. The ATLAS liquid Argon calorimeters read-out system

    CERN Document Server

    Blondel, A; Fayard, L; La Marra, D; Léger, A; Matricon, P; Perrot, G; Poggioli, L; Prast, J; Riu, I; Simion, S

    2004-01-01

    The calorimetry of the ATLAS experiment takes advantage of different detectors based on the liquid Argon (LAr) technology. Signals from the LAr calorimeters are processed by various stages before being delivered to the Data Acquisition system. The calorimeter cell signals are received by the front-end boards, which digitize a predetermined number of samples of the bipolar waveform and sends them to the Read-Out Driver (ROD) boards. The ROD board receives triggered data from 1028 calorimeter cells, and determines the precise energy and timing of the signals by processing the discrete samplings of the pulse. In addition, it formats the digital stream for the following elements of the DAQ chain, and performs monitoring. The architecture and functionality of the ATLAS LAr ROD board are discussed, along with the final design of the Processing Unit boards housing the Digital Signal Processors (DSP). (9 refs).

  2. Electron-ion recombination study in argon at atmospheric pressure

    International Nuclear Information System (INIS)

    This study deals with a wall-stabilized arc burning in argon at atmospheric pressure. A transient mode is obtained using a fast thyristor connected to the electrodes, which short-circuits the discharge. By means of two wavelengths laser interferometry and spectroscopy measurements we have determined the temporal changes of the electron density, ground state atom density and excited atom density. We have shown that, when the electric field is suppressed, the electron temperature rapidly decreases to the gas temperature before changing electron and atom densities. This phenomenon is applied to determine the gas temperature and to evaluate the role played by ionization in electron density balance. The coefficients of ambipolar diffusion, ionization and recombination and an apparent recombination coefficient are determined versus electron temperature and compared with theoretical values

  3. Morphology and structural development of reduced anatase-TiO2 by pure Ti powder upon annealing and nitridation: Synthesis of TiOx and TiOxNy powders

    International Nuclear Information System (INIS)

    It is well known that nitriding of titanium is suitable for surface coating of biomaterials and in other applications such as anti-reflective coating, while oxygen-rich titanium oxynitride has been applied in thin film resistors and photocatalysis. Thus in this work anatase was reduced with pure titanium powder during annealing in argon. This was done to avoid any metallic contamination and unwanted residual metal doping. As a result, interesting and different types of particle morphology were synthesized when the pre-milled elemental anatase and titanium powders were mixed. The formation of metastable face centred cubic and monoclinic titanium monoxide was detected by the X-ray diffraction technique. The phases were confirmed by energy dispersive X-ray spectroscopy analysis. Raman analysis revealed weak intensity peaks for samples annealed in argon as compared to those annealed under nitrogen. - Graphical abstract: Display Omitted - Highlights: • Reaction of TiO2 and Ti induced metastable FCC and monoclinic TiOx. • Compositions of mixed powder were prepared from the unmilled and pre-milled powders. • Nitridation of TiOx yielded TiOxNy phase. • Mixed morphology was observed on all three powder samples

  4. Morphology and structural development of reduced anatase-TiO{sub 2} by pure Ti powder upon annealing and nitridation: Synthesis of TiO{sub x} and TiO{sub x}N{sub y} powders

    Energy Technology Data Exchange (ETDEWEB)

    Bolokang, A.S., E-mail: Sylvester.Bolokang@transnet.net [Department of Physics, University of the Western Cape, Private Bag x 17, Bellville 7535 (South Africa); DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria 0001 (South Africa); Transnet Engineering, Product Development, Private Bag X 528, Kilnerpark 0127 (South Africa); Motaung, D.E., E-mail: dmotaung@csir.co.za [DST/CSIR National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, Pretoria 0001 (South Africa); Arendse, C.J.; Muller, T.F.G. [Department of Physics, University of the Western Cape, Private Bag x 17, Bellville 7535 (South Africa)

    2015-02-15

    It is well known that nitriding of titanium is suitable for surface coating of biomaterials and in other applications such as anti-reflective coating, while oxygen-rich titanium oxynitride has been applied in thin film resistors and photocatalysis. Thus in this work anatase was reduced with pure titanium powder during annealing in argon. This was done to avoid any metallic contamination and unwanted residual metal doping. As a result, interesting and different types of particle morphology were synthesized when the pre-milled elemental anatase and titanium powders were mixed. The formation of metastable face centred cubic and monoclinic titanium monoxide was detected by the X-ray diffraction technique. The phases were confirmed by energy dispersive X-ray spectroscopy analysis. Raman analysis revealed weak intensity peaks for samples annealed in argon as compared to those annealed under nitrogen. - Graphical abstract: Display Omitted - Highlights: • Reaction of TiO{sub 2} and Ti induced metastable FCC and monoclinic TiO{sub x}. • Compositions of mixed powder were prepared from the unmilled and pre-milled powders. • Nitridation of TiO{sub x} yielded TiO{sub x}N{sub y} phase. • Mixed morphology was observed on all three powder samples.

  5. High efficiency III-nitride light-emitting diodes

    Science.gov (United States)

    Crawford, Mary; Koleske, Daniel; Cho, Jaehee; Zhu, Di; Noemaun, Ahmed; Schubert, Martin F; Schubert, E. Fred

    2013-05-28

    Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

  6. Preparation of Ultra-fine Aluminum Nitride in Thermal Plasma

    Institute of Scientific and Technical Information of China (English)

    漆继红; 罗义文; 印永祥; 代晓雁

    2002-01-01

    Ultra-fine aluminum nitride has been synthesized by the evaporation of aluminum powder at atmospheric-pressure nitrogen plasma in a hot-wall reactor. The average size of aluminum nitride particle is 0.11μm measured by scanning electric mirror (SEM), and the purity is at least over 90% evaluated by X-Ray diffraction (XRD). The conversion of Al powder to aluminum nitride is strongly depended on the injection of NH3. Typical experimental parameters such as the feed rate of raw material, the flow rate of ammonia and the position of injecting aluminum powder into the reactor are given.

  7. Local Heating with Lithographically Fabricated Plasmonic Titanium Nitride Nanoparticles

    DEFF Research Database (Denmark)

    Guler, Urcan; Ndukaife, Justus C.; Naik, Gururaj V.;

    2013-01-01

    Titanium nitride is considered a promising alternative plasmonic material and is known to exhibit localized surface plasmon resonances within the near-infrared biological transparency window. Here, local heating efficiencies of disk-shaped nanoparticles made of titanium nitride and gold...... are compared in the visible and near-infrared regions numerically and experimentally with samples fabricated using e-beam lithography. Results show that plasmonic titanium nitride nanodisks are efficient local heat sources and outperform gold nanodisks in the biological transparency window, dispensing the need...

  8. Conductive and robust nitride buffer layers on biaxially textured substrates

    Science.gov (United States)

    Sankar, Sambasivan [Chicago, IL; Goyal, Amit [Knoxville, TN; Barnett, Scott A [Evanston, IL; Kim, Ilwon [Skokie, IL; Kroeger, Donald M [Knoxville, TN

    2009-03-31

    The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metals and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layer. In some embodiments the article further comprises electromagnetic devices which may have superconducting properties.

  9. A high Tc superconductor bolometer on a silicon nitride membrane

    OpenAIRE

    Sanchez, Stefan; Elwenspoek, Miko; Gui, Chengqun; Nivelle, de, M.J.M.E.; De, Vries; Korte, de, N.; Bruijn, Marcel P.; Wijnbergen, Jan J.; Michalke, Wolfgang; Steinbeiss, Erwin; Heidenblut, Torsten; Schwierzi, Bernard

    1998-01-01

    In this paper, we describe the design, fabrication, and performance of a high-Tc GdBa2Cu3O7-¿ superconductor bolometer positioned on a 2× 2-mm2 1-¿m-thick silicon nitride membrane. The bolometer structure has an effective area of 0.64 mm2 and was grown on a specially developed silicon-on-nitride (SON) layer. This layer was made by direct bonding of silicon nitride to silicon after chemical mechanical polishing. The operation temperature of the bolometer is 85 K. A thermal conductance G=3.3·10...

  10. Application Of Active Screen Method For Ion Nitriding Efficiency Improvement

    Directory of Open Access Journals (Sweden)

    Ogórek M.

    2015-06-01

    Full Text Available Paper presents the research of austenitic steel AISI 304 after ion nitriding at 400°C and at t =4h, for the two different variants of samples distribution in the working plasma reactive chamber tube. In order to assess the effectiveness of ion nitriding variants emission spectroscopy – GDOES, surface hardness tests, microstructure research (LM of nitrided layers were made. It has been found that the use of active screens increases the surface layer thickness and depth of nitrogen diffusion into austenitic steel 304.

  11. Limitations to band gap tuning in nitride semiconductor alloys

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede;

    2010-01-01

    Relations between the band gaps of nitride alloys and their lattice parameters are presented and limits to tuning of the fundamental gap in nitride semiconductors are set by combining a large number of experimental data with ab initio theoretical calculations. Large band gap bowings obtained...... theoretically for GaxAl1-xN, InxGa1-xN, and InxAl1-xN for uniform as well as clustered arrangements of the cation atoms are considered in the theoretical analysis. It is shown that indium plays a particular role in nitride alloys being responsible for most of the observed effects....

  12. Characteristics of Au/PZT/TiO2/Nitride/Si structure capacitors with ICP nitride treatments

    International Nuclear Information System (INIS)

    In this study, the characteristics of PZT/TiO2 ferroelectric gate stack capacitors with Inductively Coupled Plasma (ICP) nitridation were investigated for field effect transistor (FET)-type Ferroelectric Random Access Memory (FeRAM) applications. If a high accumulation capacitance is to be had, the ICP nitridation time needs to be optimized. While a short ICP treatment time results in thermal oxide growth due to lack of nitrogen, a long nitridation time causes a nitride layer which is too thick. Au/PZT(200 nm)/TiO2(40 nm)/Nitride/Si (MeFINS) structure capacitors show a memory window (ΔV) of 1.6 V under ±3-V operation while Au/PZT(200 nm)/TiO2(40 nm)/Si (MeFIS) capacitors without nitride treatment exhibit a small memory window of 0.6 V. At the same time, the capacitance of the MeFINS device is almost twice that of the MeFIS capacitor. This result implies that the ICP nitride treatment suppresses the formation of a low dielectric constant interfacial SiOx layer and alleviates the series capacitance problem

  13. Characteristics of Au/PZT/TiO{sub 2}/Nitride/Si structure capacitors with ICP nitride treatments

    Energy Technology Data Exchange (ETDEWEB)

    Min, Hyung Seob; Kim, Tae Ho; Jeon, Chang Bae; Lee, Jae Gab; Kim, Ji Young [Kookmin Univ., Seoul (Korea, Republic of)

    2002-01-01

    In this study, the characteristics of PZT/TiO{sub 2} ferroelectric gate stack capacitors with Inductively Coupled Plasma (ICP) nitridation were investigated for field effect transistor (FET)-type Ferroelectric Random Access Memory (FeRAM) applications. If a high accumulation capacitance is to be had, the ICP nitridation time needs to be optimized. While a short ICP treatment time results in thermal oxide growth due to lack of nitrogen, a long nitridation time causes a nitride layer which is too thick. Au/PZT(200 nm)/TiO{sub 2}(40 nm)/Nitride/Si (MeFINS) structure capacitors show a memory window ({delta}V) of 1.6 V under {+-}3-V operation while Au/PZT(200 nm)/TiO{sub 2}(40 nm)/Si (MeFIS) capacitors without nitride treatment exhibit a small memory window of 0.6 V. At the same time, the capacitance of the MeFINS device is almost twice that of the MeFIS capacitor. This result implies that the ICP nitride treatment suppresses the formation of a low dielectric constant interfacial SiO{sub x} layer and alleviates the series capacitance problem.

  14. Atmospheric dispersion of argon-41 from anuclear research reactor: measurement and modeling of plume geometry and gamma radiation field

    DEFF Research Database (Denmark)

    Lauritzen, Bent; Astrup, Poul; Drews, Martin;

    2003-01-01

    An atmospheric dispersion experiment was conducted using a visible tracer along with the routine release of argon-41 from the BR1 research reactor in Mol, Belgium. Simultaneous measurements of plume geometry and radiation fields for argon-41 decay were performed as well as measurements of the argon...

  15. Beryllium decorated armchair boron nitride nanoribbon: A new planar tetracoordinate nitride containing system with enhanced conductivity

    Science.gov (United States)

    Xiao, Bo; Yu, Xuefang; Hu, Hong; Ding, Yihong

    2014-07-01

    In this Letter, a new kind of planar tetracoordinate nitride (ptN) structure is obtained via Be-decorated armchair boron nitride nanoribbon (aBNNR). The high stability of such a ptN system is confirmed by both global minimization and molecular dynamical simulation at 1500 K. The results suggest that this Be-decorated aBNNR will be a thermally stable material. The electronic property of aBNNR is significantly increased after the addition of Be atoms to the edges and the band gap decreases as the width of the ribbon decreases. Our Letter posits a new and potentially stable and useful BNNR and augments the literature on ptN.

  16. Preparation of carbon-nitride bulk samples in the presence of seed carbon-nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. I. [Korea University of Technology and Education, Chonan (Korea, Republic of); Zorov, N. B. [Moscow State University, Moscow (Russian Federation)

    2004-05-15

    A procedure was developed for preparing bulk carbon-nitride crystals from polymeric alpha-C{sub 3}N{sub 4.2} at high pressure and high temperature in the presence of seeds of crystalline carbon-nitride films prepared by using a high-voltage discharge plasma combined with pulsed laser ablation of a graphite target. The samples were evaluated by using X-ray photoelectron spectroscopy (XPS), infrared (IR) spectroscopy, Auger electron spectroscopy (AES), secondary-ion mass spectrometry (SIMS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Notably, XPS studies of the film composition before and after thermobaric treatments demonstrated that the nitrogen composition in the alpha-C{sub 3}N{sub 4.2} material, which initially contained more than 58 % nitrogen, decreased during the annealing process and reached a common, stable composition of approx 45 %. The thermobaric experiments were performed at 10 - 77 kbar and 350 - 1200 .deg. C.

  17. High Temperature Oxidation of Boron Nitride. Part 1; Monolithic Boron Nitride

    Science.gov (United States)

    Jacobson, Nathan; Farmer, Serene; Moore, Arthur; Sayir, Haluk

    1997-01-01

    High temperature oxidation of monolithic boron nitride (BN) is examined. Hot pressed BN and both low and high density CVD BN were studied. It is shown that oxidation rates are quite sensitive to microstructural factors such as orientation, porosity, and degree of crystallinity. In addition small amounts of water vapor lead to volatilization of the B2O3 oxide as H(x)B(y)O(z). For these reasons, very different oxidation kinetics were observed for each type of BN.

  18. Fabrication of Aluminum Gallium Nitride/Gallium Nitride MESFET And It's Applications in Biosensing

    Science.gov (United States)

    Alur, Siddharth

    Gallium Nitride has been researched extensively for the past three decades for its application in Light Emitting Diodes (LED's), power devices and UV photodetectors. With the recent developments in crystal growth technology and the ability to control the doping there has been an increased interest in heterostructures formed between Gallium nitride and it's alloy Aluminium Gallium Nitride. These heterostructures due to the combined effect of spontaneous and piezoelectric effect can form a high density and a high mobility electron gas channel without any intentional doping. This high density electron gas makes these heterostructures ideal to be used as sensors. Gallium Nitride is also chemically very stable. Detection of biomolecules in a fast and reliable manner is very important in the areas of food safety and medical research. For biomolecular detection it is paramount to have a robust binding of the probes on the sensor surface. Therefore, in this dissertation, the fabrication and application of the AlGaN/GaN heterostructures as biological sensors for the detection of DNA and Organophosphate hydrolase enzyme is discussed. In order to use these AlGaN/GaN heterostructures as biological sensors capable of working in a liquid environment photodefinable polydimethyl-siloxane is used as an encapsulant. The immobilization conditions for a robust binding of thiolated DNA and the catalytic receptor enzyme organophosphate hydrolase on gold surfaces is developed with the help of X-ray photoelectron spectroscopy. DNA and OPH are detected by measuring the change in the drain current of the device as a function of time.

  19. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Science.gov (United States)

    Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  20. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J. [INP-Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Börner, K.; Burlacov, I.; Spies, H.-J. [TU Bergakademie Freiberg, Institute of Materials Engineering, Gustav-Zeuner-Str. 5, 09599 Freiberg (Germany); Strämke, M.; Strämke, S. [ELTRO GmbH, Arnold-Sommerfeld-Ring 3, 52499 Baesweiler (Germany)

    2015-12-15

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.

  1. Microstructure and Hardness of High Temperature Gas Nitrided AISI 420 Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ibrahim Nor Nurulhuda Md.

    2014-07-01

    Full Text Available This study examined the microstructure and hardness of as-received and nitrided AISI 420 martensitic stainless steels. High temperature gas nitriding was employed to treat the steels at 1200°C for one hour and four hours using nitrogen gas, followed by furnace cooled. Chromium nitride and iron nitride were formed and concentrated at the outmost surface area of the steels since this region contained the highest concentration of nitrogen. The grain size enlarged at the interior region of the nitrided steels due to nitriding at temperature above the recrystallization temperature of the steel and followed by slow cooling. The nitrided steels produced higher surface hardness compared to as-received steel due to the presence of nitrogen and the precipitation of nitrides. Harder steel was produced when nitriding at four hours compared to one hour since more nitrogen permeated into the steel.

  2. Physics of wurtzite nitrides and oxides passport to devices

    CERN Document Server

    Gil, Bernard

    2014-01-01

    This book gives a survey of the current state of the art of a special class of nitrides semiconductors, Wurtzite Nitride and Oxide Semiconductors. It includes properties, growth and applications. Research in the area of nitrides semiconductors is still booming although some basic materials sciences issues were solved already about 20 years ago. With the advent of modern technologies and the successful growth of nitride substrates, these materials currently experience a second birth. Advanced new applications like light-emitters, including UV operating LEDs, normally on and normally off high frequency operating transistors are expected. With progress in clean room technology, advanced photonic and quantum optic applications are envisioned in a close future. This area of research is fascinating for researchers and students in materials science, electrical engineering, chemistry, electronics, physics and biophysics. This book aims to be the ad-hoc instrument to this active field of research.

  3. Thermal Effect of Ceramic Nanofiller Aluminium Nitride on Polyethylene Properties

    Directory of Open Access Journals (Sweden)

    Omer Bin Sohail

    2012-01-01

    Full Text Available Ethylene polymerization was done to form polyethylene nano-composite with nanoaluminum nitride using zirconocene catalysts. Results show that the catalytic activity is maximum at a filler loading of 15 mg nanoaluminum nitride. Differential scanning calorimeter (DSC and X-ray diffraction (XRD results show that percentage crystallinity was also marginally higher at this amount of filler. Thermal behavior of polyethylene nanocomposites (0, 15, 30, and 45 mg was studied by DSC and thermal gravimetric analyzer (TGA. Morphology of the component with 15 mg aluminium nitride is more fibrous as compared to 0 mg aluminium nitride and higher filler loading as shown by SEM images. In order to understand combustibility behavior, tests were performed on microcalorimeter. Its results showed decrease in combustibility in polyethylene nanocomposites as the filler loading increases.

  4. Plasma-nitriding of tantalum at relatively low temperature

    Institute of Scientific and Technical Information of China (English)

    ZHANG Deyuan; LIN Qin; ZHAO Haomin; FEI Qinyong; GENG Man

    2004-01-01

    The combined quadratic orthogonal regression method of experiment design was employed to explore the effects of process parameters of plasma nitriding of tantalum such as total pressure, temperature and original hydrogen molar fraction on the hardness, roughness and structure of nitriding surfaces. The regression equations of hardness, roughness and structure were given according to the results of regression and statistic analysis. And the diffusion activation energy of nitrogen in tantalum on plasma nitriding conditions was calculated according to the experimental data of hardness of plasma-nitriding of tantalum vs time and temperature. The diffusion activation energy calculated belongs to (155.49 + 10.51)kJ/mol (783-983 K).

  5. Research of functional properties of nitride ion-plasma coatings

    Science.gov (United States)

    Vaulina, O. Yu; Ovechkin, B. B.; Papchenko, A. V.; Shvagrukova, E. V.

    2016-02-01

    This paper considers the influence of ion-plasma coatings with the use of nitrogen (N), zirconium nitride (ZrN), titanium-aluminum nitride (Ti,Al)N and titanium nitride and zirconium nitride by-layer (TiN+ZrN - eight layers) on the properties of steel 65X13. The main functional properties of the coatings are determined: microhardness, nanohardness, Young's modulus and corrosion resistance. It is shown that all the types of coatings allow increasing the physical and mechanical characteristics of instrument steel 65X13. Hardness and wear-resistance, depending on the type of the deposited coating, increase from 1, 5 to 4 times, corrosion resistance increases by tens times.

  6. Argon Kα measurement on DIII endash D by Ross filters technique (abstract)

    International Nuclear Information System (INIS)

    Techniques to reduce the heat flux to the divertor plates in tokamak power plants and the consequent erosion of, and subsequent damage to the divertor target plates include the injection of impurities such as argon, that can dissipate the energy (through radiative or collisional processes) before it reaches the target plates. An important issue with this type of scheme is poisoning of the plasma core by the impurities introduced in the divertor region. Subsequently, there is a desire to measure the profiles of the injected impurities in the core. X-ray Ross filters with an effective narrow band pass centered on the argon Kα line at 3.2 keV, have been installed on two of the existing x-ray arrays on DIII endash D in order to help determine the argon concentration profiles. Emissivity profiles of the Kα lines and the emissivity profiles for the argon enhanced continuum can be inferred from the inverted filtered x-ray brightness signals if Te, ne, and Ar18+ profiles are known. The MIST code is used to couple the filtered x-ray signals to the time dependent measurements of Te and ne. Further, the Ar16+ profiles measured by charge transfer spectroscopy, are used as a constraint on the MIST code runs to calculate Ar18+ profiles and unfold the argon emissivity profiles. A discussion of the Ross filters, the DIII endash D argon data, and the data analysis scheme for inferring argon emissivity profiles will be discussed. Estimates of the total argon concentration in the core determined from this technique in DIII endash D argon puff experiments will be presented. copyright 1999 American Institute of Physics

  7. Infrared Dielectric Properties of Low-stress Silicon Nitride

    Science.gov (United States)

    Cataldo, Giuseppe; Beall, James A.; Cho, Hsiao-Mei; McAndrew, Brendan; Niemack, Michael D.; Wollack, Edward J.

    2012-01-01

    Silicon nitride thin films play an important role in the realization of sensors, filters, and high-performance circuits. Estimates of the dielectric function in the far- and mid-IR regime are derived from the observed transmittance spectra for a commonly employed low-stress silicon nitride formulation. The experimental, modeling, and numerical methods used to extract the dielectric parameters with an accuracy of approximately 4% are presented.

  8. LASER GAS NITRIDING OF TITANIUM AND TITANIUM ALLOYS

    OpenAIRE

    J. J. DAI; Hou, S. Q.

    2009-01-01

    Titanium and titanium alloys are widely used in many fields due to some of their characteristics such as light density, high strength, and excellent corrosion resistance. However, poor mechanical performances limit their practical applications. Laser gas nitriding is a promising method used to improve the surface properties of components. Recent developments on laser gas nitriding of titanium and titanium alloys are reviewed. The processing parameters have important effects on the resulting c...

  9. Triple templating of graphitic carbon nitride to enhance photocatalytic properties

    Directory of Open Access Journals (Sweden)

    Z. Yang

    2016-01-01

    Full Text Available Graphitic carbon nitride materials show some promising properties for applications such as photocatalytic water splitting. However, the conversion efficiency is still low due to factors such as a low surface area and limited light absorption. In this paper, we describe a “triple templating” approach to generating porous graphitic carbon nitride. The introduction of pores on several length-scales results in enhanced photocatalytic properties.

  10. Platinum group metal nitrides and carbides: synthesis, properties and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovskii, Alexander L [Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)

    2009-04-30

    Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.

  11. Research of nanocomposite structure of boron nitride at proton radiation

    OpenAIRE

    Borodin, Yuri Viktorovich; Ermolaev, D. S.; Pak, V.; Zhang, K.

    2016-01-01

    Using roentgen diffraction and electron microscopy, the influence of nanosecond irradiation by ion beams of high energy on forming of self-organized nanoblocks in near surface's layers of boron nitride (BN) has been studied. It was shown that low temperature transitions from hexagonal to wrutz boron nitrides is associated with changes of shape and sizes of self-organized particles consisting the nanoblocks. We have calculated the parameters of nanoblocks using the meanings of interplane dista...

  12. Corrosion behavior of tantalum and its nitride in alkali solution

    Institute of Scientific and Technical Information of China (English)

    ZHANG Deyuan; LIN Qin; FEI Qinyong; ZHAO Haomin; KANG Guangyu; GENG Man

    2003-01-01

    The corrosion behavior of tantalum and its nitrides in stirring NaOH solutions was researched by potenfiostatic method, cyclic voltammetry and XPS. The results showed that the corrosion products were composed of Ta2O5 and NaTaO3.The corrosion reaction formula of tantalum and its nitrides was written according to cyclic volt-ampere curves. The electric charge transfer coefficient and the electric charge transfer number were calculated.

  13. Grafting titanium nitride surfaces with sodium styrene sulfonate thin films

    OpenAIRE

    Zorn, Gilad; MIGONNEY, Véronique; Castner, David G.

    2014-01-01

    The importance of titanium nitride lies in its high hardness and its remarkable resistance to wear and corrosion, which has led to its use as a coating for the heads of hip prostheses, dental implants and dental surgery tools. However, the usefulness of titanium nitride coatings for biomedical applications could be significantly enhanced by modifying their surface with a bioactive polymer film. The main focus of the present work was to graft a bioactive poly(sodium styrene sulf...

  14. Cubic boron nitride- a new material for ultracold neutron application

    International Nuclear Information System (INIS)

    For the first time, the Fermi potential of cubic boron nitride (cBN) was measured at the ultra cold neutron source at the TRIGA reactor, Mainz using the time of flight method (TOF). The investigated samples have a Fermi potential of about 300 neV. Because of its good dielectric characteristics, cubic boron nitride could be used as suitable coating for insulator in storage chambers of future EDM projects. This talk presents recent results and an outlook on further investigations.

  15. Study on Titanium Nitride Film Modified for Intraocular Lens

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective:To study the characteristics of the intraocular lens using ion beam sputtering depositing titanium nitride thin film on the intraocular lens(IOLs).Methods:To deposite titanium nitride thin film on the top of intraocular lens by ion beam sputtering depositing.We analyzed the surface morphology of intraocular lens through SEM and AFM.We detected intraocular lens resolution through the measurement of intraocular lens.Biocompatibility of intraocular lens is preliminary evaluated in this test.Results:T...

  16. Apparatus for the production of boron nitride nanotubes

    Science.gov (United States)

    Smith, Michael W; Jordan, Kevin

    2014-06-17

    An apparatus for the large scale production of boron nitride nanotubes comprising; a pressure chamber containing; a continuously fed boron containing target; a source of thermal energy preferably a focused laser beam; a cooled condenser; a source of pressurized nitrogen gas; and a mechanism for extracting boron nitride nanotubes that are condensed on or in the area of the cooled condenser from the pressure chamber.

  17. Vertical transport in graphene-hexagonal boron nitride heterostructure devices

    OpenAIRE

    Samantha Bruzzone; Demetrio Logoteta; Gianluca Fiori; Giuseppe Iannaccone

    2015-01-01

    Research in graphene-based electronics is recently focusing on devices based on vertical heterostructures of two-dimensional materials. Here we use density functional theory and multiscale simulations to investigate the tunneling properties of single- and double-barrier structures with graphene and few-layer hexagonal boron nitride (h-BN) or hexagonal boron carbon nitride (h-BC2N). We find that tunneling through a single barrier exhibit a weak dependence on energy. We also show that in double...

  18. Performance of chromium nitride based coatings under plastic processing conditions

    OpenAIRE

    Cunha, l.; Andritschky, M.; Pischow, K.; Wang, Z.(Institute of High Energy Physics, Beijing, China); Zarychta, A.; Miranda, A. S.; A.M. Cunha

    2000-01-01

    Chromium nitride based coatings were produced in the form of monolithic and multilayer coatings, by DC and RF reactive magnetron sputtering. These coatings were deposited onto stainless steel and tool steel substrates. Chromium nitride coatings have;proved to be wear and corrosion resistant. The combination of these characteristics was necessary to protect surfaces during plastic processing. In order to select the best coatings, some mechanical and tribological tests were performed. Har...

  19. Optical loss analysis of silicon rich nitride waveguides

    DEFF Research Database (Denmark)

    Mertens, Hans; Andersen, Karin Nordström; Svendsen, Winnie Edith

    2002-01-01

    An analysis of the propagation loss in high-index LPCVD-grown silicon rich nitride (SRN) slab waveguides and channel waveguides is presented. A propagation loss as low as 0.6 dB/cm has been achieved.......An analysis of the propagation loss in high-index LPCVD-grown silicon rich nitride (SRN) slab waveguides and channel waveguides is presented. A propagation loss as low as 0.6 dB/cm has been achieved....

  20. Low temperature gaseous nitriding of Ni based superalloys

    DEFF Research Database (Denmark)

    Eliasen, K. M.; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2010-01-01

    In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr......In the present work the nitriding response of selected Ni based superalloys at low temperatures is addressed. The alloys investigated are nimonic series nos. 80, 90, 95 and 100 and nichrome (Ni/Cr...

  1. Four-Wave Mixing in Silicon-Rich Nitride Waveguides

    DEFF Research Database (Denmark)

    Mitrovic, Miranda; Guan, Xiaowei; Ji, Hua;

    2015-01-01

    We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss.......We demonstrate four-wave mixing wavelength conversion in silicon-rich nitride waveguides which are a promising alternative to silicon for nonlinear applications. The obtained conversion efficiency reaches -13.6 dB while showing no significant nonlinear loss....

  2. Nitrogen Atom Transfer From High Valent Iron Nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael D. [New Mexico State Univ., Las Cruces, NM (United States); Smith, Jeremy M. [Indiana Univ., Bloomington, IN (United States)

    2015-10-14

    This report describes the synthesis and reactions of high valent iron nitrides. Organonitrogen compounds such as aziridines are useful species for organic synthesis, but there are few efficient methods for their synthesis. Using iron nitrides to catalytically access these species may allow for their synthesis in an energy-and atom-efficient manner. We have developed a new ligand framework to achieve these goals as well as providing a method for inducing previously unknown reactivity.

  3. Laser ablation of molecular carbon nitride compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, D., E-mail: d.fischer@fkf.mpg.de [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Schwinghammer, K. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Department of Chemistry, University of Munich, LMU, Butenandtstr. 5-13, 81377 Munich (Germany); Nanosystems Initiative Munich (NIM) and Center for Nanoscience (CeNS), 80799 Munich (Germany); Sondermann, C. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Department of Chemistry, University of Munich, LMU, Butenandtstr. 5-13, 81377 Munich (Germany); Lau, V.W.; Mannhart, J. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Lotsch, B.V. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Department of Chemistry, University of Munich, LMU, Butenandtstr. 5-13, 81377 Munich (Germany); Nanosystems Initiative Munich (NIM) and Center for Nanoscience (CeNS), 80799 Munich (Germany)

    2015-09-15

    We present a method for the preparation of thin films on sapphire substrates of the carbon nitride precursors dicyandiamide (C{sub 2}N{sub 4}H{sub 4}), melamine (C{sub 3}N{sub 6}H{sub 6}), and melem (C{sub 6}N{sub 10}H{sub 6}), using the femtosecond-pulsed laser deposition technique (femto-PLD) at different temperatures. The depositions were carried out under high vacuum with a femtosecond-pulsed laser. The focused laser beam is scanned on the surface of a rotating target consisting of the pelletized compounds. The resulting polycrystalline, opaque films were characterized by X-ray powder diffraction, infrared, Raman, and X-ray photoelectron spectroscopy, photoluminescence, SEM, and MALDI-TOF mass spectrometry measurements. The crystal structures and optical/spectroscopic results of the obtained rough films largely match those of the bulk materials.

  4. Pure and doped boron nitride nanotubes

    Directory of Open Access Journals (Sweden)

    M. Terrones

    2007-05-01

    Full Text Available More than ten years ago, it was suggested theoretically that boron nitride (BN nanotubes could be produced. Soon after, various reports on their synthesis appeared and a new area of nanotube science was born. This review aims to cover the latest advances related to the synthesis of BN nanotubes. We show that these tubes can now be produced in larger amounts and, in particular, that the chemistry of BN tubes appears to be very important to the production of reinforced composites with insulating characteristics. From the theoretical standpoint, we also show that (BN-C heteronanotubes could have important implications for nanoelectronics. We believe that BN nanotubes (pure and doped could be used in the fabrication of novel devices in which pure carbon nanotubes do not perform very efficiently.

  5. Thermal Conductivity of Uranium Nitride and Carbide

    Directory of Open Access Journals (Sweden)

    B. Szpunar

    2014-01-01

    Full Text Available We investigate the electronic thermal conductivity of alternative fuels like uranium nitride and uranium carbide. We evaluate the electronic contribution to the thermal conductivity, by combining first-principles quantum-mechanical calculations with semiclassical correlations. The electronic structure of UN and UC was calculated using Quantum Espresso code. The spin polarized calculations were performed for a ferromagnetic and antiferromagnetic ordering of magnetic moments on uranium lattice and magnetic moment in UC was lower than in UN due to stronger hybridization between 2p electrons of carbon and 5f electrons of uranium. The nonmagnetic electronic structure calculations were used as an input to BolzTrap code that was used to evaluate the electronic thermal conductivity. It is predicted that the thermal conductivity should increase with the temperature increase, but to get a quantitative agreement with the experiment at higher temperatures the interaction of electrons with phonons (and electron-electron scattering needs to be included.

  6. Quantum emission from hexagonal boron nitride monolayers.

    Science.gov (United States)

    Tran, Toan Trong; Bray, Kerem; Ford, Michael J; Toth, Milos; Aharonovich, Igor

    2016-01-01

    Artificial atomic systems in solids are widely considered the leading physical system for a variety of quantum technologies, including quantum communications, computing and metrology. To date, however, room-temperature quantum emitters have only been observed in wide-bandgap semiconductors such as diamond and silicon carbide, nanocrystal quantum dots, and most recently in carbon nanotubes. Single-photon emission from two-dimensional materials has been reported, but only at cryogenic temperatures. Here, we demonstrate room-temperature, polarized and ultrabright single-photon emission from a colour centre in two-dimensional hexagonal boron nitride. Density functional theory calculations indicate that vacancy-related defects are a probable source of the emission. Our results demonstrate the unprecedented potential of van der Waals crystals for large-scale nanophotonics and quantum information processing. PMID:26501751

  7. Boron nitride: A new photonic material

    Energy Technology Data Exchange (ETDEWEB)

    Chubarov, M., E-mail: mihcu@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Pedersen, H., E-mail: henke@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Högberg, H., E-mail: hanho@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Filippov, S., E-mail: stafi@ifm.liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Engelbrecht, J.A.A., E-mail: Japie.Engelbrecht@nmmu.ac.za [Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); O' Connel, J., E-mail: jacques.oconnell@gmail.com [Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Henry, A., E-mail: anne.henry@liu.se [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden)

    2014-04-15

    Rhombohedral boron nitride (r-BN) layers were grown on sapphire substrate in a hot-wall chemical vapor deposition reactor. Characterization of these layers is reported in details. X-ray diffraction (XRD) is used as a routine characterization tool to investigate the crystalline quality of the films and the identification of the phases is revealed using detailed pole figure measurements. Transmission electron microscopy reveals stacking of more than 40 atomic layers. Results from Fourier Transform InfraRed (FTIR) spectroscopy measurements are compared with XRD data showing that FTIR is not phase sensitive when various phases of sp{sup 2}-BN are investigated. XRD measurements show a significant improvement of the crystalline quality when adding silicon to the gas mixture during the growth; this is further confirmed by cathodoluminescence which shows a decrease of the defects related luminescence intensity.

  8. Hexagonal boron nitride and water interaction parameters

    Science.gov (United States)

    Wu, Yanbin; Wagner, Lucas K.; Aluru, Narayana R.

    2016-04-01

    The study of hexagonal boron nitride (hBN) in microfluidic and nanofluidic applications at the atomic level requires accurate force field parameters to describe the water-hBN interaction. In this work, we begin with benchmark quality first principles quantum Monte Carlo calculations on the interaction energy between water and hBN, which are used to validate random phase approximation (RPA) calculations. We then proceed with RPA to derive force field parameters, which are used to simulate water contact angle on bulk hBN, attaining a value within the experimental uncertainties. This paper demonstrates that end-to-end multiscale modeling, starting at detailed many-body quantum mechanics and ending with macroscopic properties, with the approximations controlled along the way, is feasible for these systems.

  9. Boron nitride: A new photonic material

    International Nuclear Information System (INIS)

    Rhombohedral boron nitride (r-BN) layers were grown on sapphire substrate in a hot-wall chemical vapor deposition reactor. Characterization of these layers is reported in details. X-ray diffraction (XRD) is used as a routine characterization tool to investigate the crystalline quality of the films and the identification of the phases is revealed using detailed pole figure measurements. Transmission electron microscopy reveals stacking of more than 40 atomic layers. Results from Fourier Transform InfraRed (FTIR) spectroscopy measurements are compared with XRD data showing that FTIR is not phase sensitive when various phases of sp2-BN are investigated. XRD measurements show a significant improvement of the crystalline quality when adding silicon to the gas mixture during the growth; this is further confirmed by cathodoluminescence which shows a decrease of the defects related luminescence intensity.

  10. Thermal tuners on a Silicon Nitride platform

    CERN Document Server

    Pérez, Daniel; Baños, Rocío; Doménech, José David; Sánchez, Ana M; Cirera, Josep M; Mas, Roser; Sánchez, Javier; Durán, Sara; Pardo, Emilio; Domínguez, Carlos; Pastor, Daniel; Capmany, José; Muñoz, Pascual

    2016-01-01

    In this paper, the design trade-offs for the implementation of small footprint thermal tuners on silicon nitride are presented, and explored through measurements and supporting simulations of a photonic chip based on Mach-Zehnder Interferometers. Firstly, the electrical properties of the tuners are assessed, showing a compromise between compactness and deterioration. Secondly, the different variables involved in the thermal efficiency, switching power and heater dimensions, are analysed. Finally, with focus on exploring the limits of this compact tuners with regards to on chip component density, the thermal-cross talk is also investigated. Tuners with footprint of 270x5 {\\mu}m 2 and switching power of 350 mW are reported, with thermal-cross talk, in terms of induced phase change in adjacent devices of less than one order of magnitude at distances over 20 {\\mu}m. Paths for the improvement of thermal efficiency, power consumption and resilience of the devices are also outlined

  11. Carbon nitride frameworks and dense crystalline polymorphs

    Science.gov (United States)

    Pickard, Chris J.; Salamat, Ashkan; Bojdys, Michael J.; Needs, Richard J.; McMillan, Paul F.

    2016-09-01

    We used ab initio random structure searching (AIRSS) to investigate polymorphism in C3N4 carbon nitride as a function of pressure. Our calculations reveal new framework structures, including a particularly stable chiral polymorph of space group P 43212 containing mixed s p2 and s p3 bonding, that we have produced experimentally and recovered to ambient conditions. As pressure is increased a sequence of structures with fully s p3 -bonded C atoms and three-fold-coordinated N atoms is predicted, culminating in a dense P n m a phase above 250 GPa. Beyond 650 GPa we find that C3N4 becomes unstable to decomposition into diamond and pyrite-structured CN2.

  12. Gallium Nitride Room Temperature α Particle Detectors

    International Nuclear Information System (INIS)

    Gallium Nitride (GaN) room temperature α particle detectors are fabricated and characterized, whose device structure is Schottky diode. The current-voltage (I – V) measurements reveal that the reverse breakdown voltage of the detectors is more than 200 V owing to the consummate fabrication processes, and that the Schottky barrier and ideal factor of the detectors are 0.64 eV and 1.02, respectively, calculated from the thermionic transmission model. 241Am α particles pulse height spectra from the GaN detectors biased at −8 V is obviously one Gauss peak located at channel 44 with the full width at half maximum (FWHM) of 15.87 in channel. One of the main reasons for the relatively wider FWHM is that the air between the detectors and isotope could widen the spectrum

  13. Mechanical Hysteresis of Hexagonal Boron Nitride

    Institute of Scientific and Technical Information of China (English)

    ZHOU Aiguo; LI Haoran

    2011-01-01

    Hexagonal boron nitride (h-BN) is an important structural material with layered microstructure.Because of the plastic anisotropy,this material shows obvious mechanical hysteresis (nonlinear elastic deformation).There are hysteretic loops at the cyclical load-unload stress-strain curves of h-BN.Consequently,two hot-pressed h-BN cylinders with different textures were studied.The mechanical hysteresis is heavily texture-dependent.The area of hysteretic loop is linearly related with the square of loading stresslevel.Two minor loops attached on the hysteretic loops with the same extreme stresses have congruent shapes.It can be concluded that the mechanical hysteresis of h-BN can he explained by a Kink Nonlinear Elastic model developed from the study of a ternary carbide Ti3SiC2.

  14. Synthesis and characterization of boron nitrides nanotubes

    International Nuclear Information System (INIS)

    This paper presents a new synthesis for the production of boron nitride nanotubes (BNNT) from boron powder, ammonium nitrate and hematite tube furnace CVD method. The samples were subjected to some characterization techniques as infrared spectroscopy, thermal analysis, X-ray diffraction and scanning electron microscopy and transmission. By analyzing the results can explain the chemical reactions involved in the process and confirm the formation of BNNT with several layers and about 30 nanometers in diameter. Due to excellent mechanical properties and its chemical and thermal stability this material is promising for various applications. However, BNNT has received much less attention than carbon nanotubes, it is because of great difficulty to synthesize appreciable quantities from the techniques currently known, and this is one of the main reasons this work.(author)

  15. Excitons in boron nitride single layer

    Science.gov (United States)

    Galvani, Thomas; Paleari, Fulvio; Miranda, Henrique P. C.; Molina-Sánchez, Alejandro; Wirtz, Ludger; Latil, Sylvain; Amara, Hakim; Ducastelle, François

    2016-09-01

    Boron nitride single layer belongs to the family of two-dimensional materials whose optical properties are currently receiving considerable attention. Strong excitonic effects have already been observed in the bulk and still stronger effects are predicted for single layers. We present here a detailed study of these properties by combining ab initio calculations and a tight-binding Wannier analysis in both real and reciprocal space. Due to the simplicity of the band structure with single valence (π ) and conduction (π*) bands the tight-binding analysis becomes quasiquantitative with only two adjustable parameters and provides tools for a detailed analysis of the exciton properties. Strong deviations from the usual hydrogenic model are evidenced. The ground-state exciton is not a genuine Frenkel exciton, but a very localized tightly bound one. The other ones are similar to those found in transition-metal dichalcogenides and, although more localized, can be described within a Wannier-Mott scheme.

  16. Hexagonal boron nitride and water interaction parameters.

    Science.gov (United States)

    Wu, Yanbin; Wagner, Lucas K; Aluru, Narayana R

    2016-04-28

    The study of hexagonal boron nitride (hBN) in microfluidic and nanofluidic applications at the atomic level requires accurate force field parameters to describe the water-hBN interaction. In this work, we begin with benchmark quality first principles quantum Monte Carlo calculations on the interaction energy between water and hBN, which are used to validate random phase approximation (RPA) calculations. We then proceed with RPA to derive force field parameters, which are used to simulate water contact angle on bulk hBN, attaining a value within the experimental uncertainties. This paper demonstrates that end-to-end multiscale modeling, starting at detailed many-body quantum mechanics and ending with macroscopic properties, with the approximations controlled along the way, is feasible for these systems. PMID:27131542

  17. Optical processes in dilute nitrides Semiconductors; Alloys

    CERN Document Server

    Potter, R J

    2003-01-01

    This thesis is concerned with the narrow bandgap semiconductor alloys known as dilute nitrides. The initial part of this project was concerned with characterisation of chemical beam epitaxy (CBE) grown samples so that growth techniques could be refined. Early samples show evidence of structural/compositional disorder resulting from the large miscibility gap induced by nitrogen. Non-equilibrium growth was employed to overcome this, eventually resulting in improved material. In the second part of this project, steady-state and time-resolved photoluminescence, along with photomodulated reflectance were employed to investigate the optical properties of molecular beam epitaxy (MBE) grown GalnNAs, GaNAs and InGaAs quantum wells (QWs). Low temperature results show evidence of carrier localization, which was interpreted in terms of structural/compositional fluctuations induced by the nitrogen incorporation. Poor photoluminescence efficiency and rapid decay of emission kinetics indicate the presence of strong non-radi...

  18. Boron Nitride Nanotube: Synthesis and Applications

    Science.gov (United States)

    Tiano, Amanda L.; Park, Cheol; Lee, Joseph W.; Luong, Hoa H.; Gibbons, Luke J.; Chu, Sang-Hyon; Applin, Samantha I.; Gnoffo, Peter; Lowther, Sharon; Kim, Hyun Jung; Danehy, Paul M.; Inman, Jennifer A.; Jones, Stephen B.; Kang, Jin Ho; Sauti, Godfrey; Thibeault, Sheila A.; Yamakov, Vesselin; Wise, Kristopher E.; Su, Ji; Fay, Catharine C.

    2014-01-01

    Scientists have predicted that carbon's immediate neighbors on the periodic chart, boron and nitrogen, may also form perfect nanotubes, since the advent of carbon nanotubes (CNTs) in 1991. First proposed then synthesized by researchers at UC Berkeley in the mid 1990's, the boron nitride nanotube (BNNT) has proven very difficult to make until now. Herein we provide an update on a catalyst-free method for synthesizing highly crystalline, small diameter BNNTs with a high aspect ratio using a high power laser under a high pressure and high temperature environment first discovered jointly by NASA/NIA JSA. Progress in purification methods, dispersion studies, BNNT mat and composite formation, and modeling and diagnostics will also be presented. The white BNNTs offer extraordinary properties including neutron radiation shielding, piezoelectricity, thermal oxidative stability (> 800 C in air), mechanical strength, and toughness. The characteristics of the novel BNNTs and BNNT polymer composites and their potential applications are discussed.

  19. Wetting and evaporation of argon nanodroplets on smooth and rough substrates: Molecular dynamics simulations

    Science.gov (United States)

    Li, Qun; Wang, Baohe; Chen, Yonggang; Zhao, Zongchang

    2016-10-01

    Wetting and evaporation behaviors of argon nanodroplets on smooth and rough substrates are studied using molecular dynamics simulations. Effects of interaction energy between solid and argon atoms on wetting and evaporation and differences between nanodroplets on smooth and rough substrates have been investigated. The results show that for both smooth and rough substrates, as the interaction energy between solid and argon atoms increases, the contact angle and total evaporation increase. For rough substrates, the variations of contact angle and contact radius during evaporation progress are much more complex and the total evaporation is much larger than that of smooth substrates.

  20. A Study of Dielectric Breakdown Along Insulators Surrounding Conductors in Liquid Argon

    CERN Document Server

    Lockwitz, Sarah

    2015-01-01

    High voltage breakdown in liquid argon is an important consideration in the design of liquid argon time projection chambers, which are often used as neutrino and dark matter detectors. We have made systematic measurements of breakdown voltages in liquid argon along insulators surrounding negative rod electrodes. The purpose of these tests is to understand the effects of materials, of breakdown path length, and of surface topology. We have found no material-specific effects other than those due to their permittivity. We have found no dependence on breakdown voltage on the length of the exposed insulator. A model for the breakdown mechanism is presented that can help inform future designs.

  1. Design Principles and Operational Results of the Cryogenic System for the ATLAS Liquid Argon Calorimeter

    CERN Document Server

    Fabre, C; Chalifour, M; Gonidec, G; Passardi, Giorgio; Petit, P; Pezzetti, M; Wicek, F

    2009-01-01

    The ATLAS liquid argon calorimeter housed in three independent cryostats containing a total argon volume of about 78 m3 has been installed in the underground cavern. The three detectors have been cooled down following stringent temperature gradient limits and have been filled with liquid argon. The cryostats are now in a stable condition for periods going up to almost two years. The temperature uniformity within each of the three detector volumes is found to be within 70 mK rms, while the temperature stability stays below 5 mK rms.

  2. A new ozone standard - The vapor pressure of ozone at liquid argon temperatures

    Science.gov (United States)

    Mauersberger, K.; Hanson, D.; Morton, J.

    1985-01-01

    The vapor pressure of ozone has been measured at liquid argon temperatures. At the normal boiling point of argon (-185.9 C) an ozone pressure of 0.0405 torr was obtained with an accuracy of + or - 1.5 percent. Increases and decreases in liquid argon temperatures raised and lowered the ozone vapor pressure, respectively. During the vapor pressure measurements the purity of ozone was monitored with a mass spectrometer. The proposed ozone standard will considerably improve the calibration of experiments for atmospheric research, the determination of absorption cross sections and other laboratory ozone studies.

  3. Surface compositional changes in GaAs subjected to argon plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Surdu-Bob, C.C.; Sullivan, J.L.; Saied, S.O.; Layberry, R.; Aflori, M

    2002-12-30

    X-ray photoelectron spectroscopy (XPS) has been employed to study surface compositional changes in GaAs (1 0 0) subjected to argon plasma treatment. The experimental results have been explained in terms of predicted argon ion energies, measured ion densities and etch rates. A model is proposed for the processes taking place at the surface of GaAs in terms of segregation, sputtering and surface relaxation. Stopping and range of ions in matter (SRIM) code has also been employedan aid to identification of the mechanisms responsible for the compositional changes. Argon plasma treatment induced surface oxidation at very low energies and sputtering and surface damage with increasing energy.

  4. Changes in a surface of polycrystalline aluminum upon bombardment with argon ions

    Science.gov (United States)

    Ashkhotov, O. G.; Ashkhotova, I. B.; Bliev, A. P.; Magkoev, T. T.; Krymshokalova, D. A.

    2014-10-01

    The interaction between argon ions and a natural oxide layer of polycrystalline aluminum is studied via Auger electron (AE) and electron energy loss (EEL) spectroscopy. It is found that bombardment with argon ions whose energy is lower than the Al2O3 sputtering threshold results in the accumulation of bombarding ions in interstitial surface voids, thus forming a supersaturated solid solution of target atoms and bombarding ions of argon and nitrogen entrapped by the ion beam from the residual gas of the working chamber of the spectrometer.

  5. Gallium Nitride Schottky betavoltaic nuclear batteries

    International Nuclear Information System (INIS)

    Research highlights: → Gallium Nitride nuclear batteries with Ni-63 are demonstrated for the first time. → Open circuit voltage of 0.1 V and conversion efficiency of 0.32% have been obtained. → The limited performance is due to thin effective energy deposition layer. → The output power is expected to greatly increase with growing thick GaN films. -- Abstract: Gallium Nitride (GaN) Schottky betavoltaic nuclear batteries (GNBB) are demonstrated in our work for the first time. GaN films are grown on sapphire substrates by metalorganic chemical vapor deposition (MOCVD), and then GaN Schottky diodes are fabricated by normal micro-fabrication process. Nickel with mass number of 63 (63Ni), which emits β particles, is loaded on the GaN Schottky diodes to achieve GNBB. X-ray diffraction (XRD) and photoluminescence (PL) are carried out to investigate the crystal quality for the GaN films as grown. Current-voltage (I-V) characteristics shows that the GaN Schottky diodes are not jet broken down at -200 V due to consummate fabrication processes, and the open circuit voltage of the GNBB is 0.1 V and the short circuit current density is 1.2 nA cm-2. The limited performance of the GNBB is due to thin effective energy deposition layer, which is only 206 nm to absorb very small partial energy of the β particles because of the relatively high dislocation density and carrier concentration. However, the conversion efficiency of 0.32% and charge collection efficiency (CCE) of 29% for the GNBB have been obtained. Therefore, the output power of the GNBB are expected to greatly increase with growing high quality thick GaN films.

  6. Improvement in Corrosion Resistance of Anchor Steel by Low Temperature Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    NIU Shaoqing; YANG Shuangsuo; LI Yi

    2014-01-01

    Plasma nitriding was used to improve the corrosion performance of anchor steel. The microstructure, phase constitution, microhardness and corrosion resistance of the nitrided layer were systematically studied. The results show that the nitrided layer is continuous and dense, and consists of Fe4N and Fe3N in the outmost surface. The microhardness of the nitrided sample is improved because of the formation of nitrides in the outer side continuous layer and the inner parts. The nitrided layer on the surface of anchor steel can effectively improve the corrosion resistance of the anchor steel.

  7. Modeling the kinetics of the nitriding and nitrocarburizing of iron

    DEFF Research Database (Denmark)

    Somers, Marcel A. J.; Mittemeijer, Eric J.

    1998-01-01

    The growth kinetics of the iron-nitride compound layer during nitriding and nitrocarburizing of pure iron has been investigated for various temperatures and various combinations of imposed nitrogen and carbon activities. The results indicate that no local equilibrium occurs at the gas/solid inter......The growth kinetics of the iron-nitride compound layer during nitriding and nitrocarburizing of pure iron has been investigated for various temperatures and various combinations of imposed nitrogen and carbon activities. The results indicate that no local equilibrium occurs at the gas....../solid interface during nitriding/nitrocarburizing, due to the slow kinetics of ammonia dissociation, the development and subsequent desorption of molecular nitrogen gas at the surface and, for the case of nitrocarburizing, the fast initial carbon uptake. The kinetics of gaseous nitriding of pure iron can...... be adequately described by a model that adopts local equilibrium at the solid/solid interfaces and a composition-weighted intrinsic diffusion coefficient of nitrogen in the Fe-N phases. For nitrocarburizing modeling appears not possible yet, due to compositions at gas/solid and solid/solid interfaces which...

  8. High-temperature nitridation of Ni-Cr alloys

    Science.gov (United States)

    Kodentsov, A. A.; Gülpen, J. H.; Cserháti, C.; Kivilahti, J. K.; van Loo, F. J. J.

    1996-01-01

    The nitriding behavior of nickel-chromium alloys was investigated at 1398 K over the range 1 to 6000 bar of external nitrogen pressure. The morphology of the nitrided zone depends on the concentration of chromium in the initial alloy and the N2 pressure (fugacity) applied upon the system. The transition from CrN to Cr2N precipitation was observed within the reaction zone after nitriding at 100 to 6000 bar of N2 when the chromium content in the initial alloys was 28.0 at. pct or higher. It is shown that the ternary phase π (Cr10Ni7N3) is formed in this system at 1273 K. through a peritectoid reaction between Cr2N and nickel solid solution and becomes unstable above 1373 K. The thermodynamic evaluation of the Ni-Cr-N system was performed and phase equilibria calculated. Evidence for “up hill” diffusion of nitrogen near the reaction front during the internal nitridation of Ni-Cr alloys at 1398 K was found. It was attributed to the relative instability of chromium nitrides and strong Cr-N interaction in the matrix of the Ni-based solid solution within the nitrided zone.

  9. The prospect of uranium nitride (UN) and mixed nitride fuel (UN-PuN) for pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Syarifah, Ratna Dewi, E-mail: syarifah.physics@gmail.com; Suud, Zaki, E-mail: szaki@fi.itb.ac.id [Nuclear Physics and Biophysics Research Division, Physics Department, Faculty of Mathematics and Natural Science, Bandung Institute of Technology Jalan Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    Design study of small Pressurized Water Reactors (PWRs) core loaded with uranium nitride fuel (UN) and mixed nitride fuel (UN-PuN), Pa-231 as burnable poison, and Americium has been performed. Pa-231 known as actinide material, have large capture cross section and can be converted into fissile material that can be utilized to reduce excess reactivity. Americium is one of minor actinides with long half life. The objective of adding americium is to decrease nuclear spent fuel in the world. The neutronic analysis results show that mixed nitride fuel have k-inf greater than uranium nitride fuel. It is caused by the addition of Pu-239 in mixed nitride fuel. In fuel fraction analysis, for uranium nitride fuel, the optimum volume fractions are 45% fuel fraction, 10% cladding and 45% moderator. In case of UN-PuN fuel, the optimum volume fractions are 30% fuel fraction, 10% cladding and 60% coolant/ moderator. The addition of Pa-231 as burnable poison for UN fuel, enrichment U-235 5%, with Pa-231 1.6% has k-inf more than one and excess reactivity of 14.45%. And for mixed nitride fuel, the lowest value of reactivity swing is when enrichment (U-235+Pu) 8% with Pa-231 0.4%, the excess reactivity value 13,76%. The fuel pin analyze for the addition of Americium, the excess reactivity value is lower than before, because Americium absorb the neutron. For UN fuel, enrichment U-235 8%, Pa-231 1.6% and Am 0.5%, the excess reactivity is 4.86%. And for mixed nitride fuel, when enrichment (U-235+Pu) 13%, Pa-231 0.4% and Am 0.1%, the excess reactivity is 11.94%. For core configuration, it is better to use heterogeneous than homogeneous core configuration, because the radial power distribution is better.

  10. Generation and Characteristics of IV-VI transition Metal Nitride and Carbide Nanoparticles using a Reactive Mesoporous Carbon Nitride

    KAUST Repository

    Alhajri, Nawal Saad

    2016-02-22

    Interstitial nitrides and carbides of early transition metals in groups IV–VI exhibit platinum-like electronic structures, which make them promising candidates to replace noble metals in various catalytic reactions. Herein, we present the preparation and characterization of nano-sized transition metal nitries and carbides of groups IV–VI (Ti, V, Nb, Ta, Cr, Mo, and W) using mesoporous graphitic carbon nitride (mpg-C3N4), which not only provides confined spaces for restricting primary particle size but also acts as a chemical source of nitrogen and carbon. We studied the reactivity of the metals with the template under N2 flow at 1023 K while keeping the weight ratio of metal to template constant at unity. The produced nanoparticles were characterized by powder X-ray diffraction, CHN elemental analysis, nitrogen sorption, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results show that Ti, V, Nb, Ta, and Cr form nitride phases with face centered cubic structure, whereas Mo and W forme carbides with hexagonal structures. The tendency to form nitride or carbide obeys the free formation energy of the transition metal nitrides and carbides. This method offers the potential to prepare the desired size, shape and phase of transition metal nitrides and carbides that are suitable for a specific reaction, which is the chief objective of materials chemistry.

  11. Nanostructures based in boro nitride thin films deposited by PLD onto Si/Si{sub 3}N{sub 4}/DLC substrate

    Energy Technology Data Exchange (ETDEWEB)

    Roman, W S; Riascos, H [Grupo Plasma, Laser y Aplicaciones, Universidad Tecnologica de Pereira (Colombia); Caicedo, J C [Grupo de PelIculas Delgadas, Universidad del Valle, Cali (Colombia); Ospina, R [Laboratorio de Plasma, Universidad Nacional de Colombia, sede Manizales (Colombia); Tirado-MejIa, L, E-mail: hriascos@utp.edu.c [Laboratorio de Optoelectronica, Universidad del Quindio (Colombia)

    2009-05-01

    Diamond-like carbon and boron nitride were deposited like nanostructered bilayer on Si/Si{sub 3}N{sub 4} substrate, both with (100) crystallographic orientation, these films were deposited through pulsed laser technique (Nd: YAG: 8 Jcm{sup -2}, 9ns). Graphite (99.99%) and boron nitride (99.99%) targets used to growth the films in argon atmosphere. The thicknesses of bilayer were determined with a perfilometer, active vibration modes were analyzed using infrared spectroscopy (FTIR), finding bands associated around 1400 cm{sup -1} for B - N bonding and bands around 1700 cm{sup -1} associated with C=C stretching vibrations of non-conjugated alkenes and azometinic groups, respectively. The crystallites of thin films were analyzed using X-ray diffraction (XRD) and determinated the h-BN (0002), alpha-Si{sub 3}N{sub 4} (101) phases. The aim of this study is to relate the dependence on physical and chemical characteristics of the system Si/Si{sub 3}N{sub 4}/DLC/BN with gas pressure adjusted at the 1.33, 2.67 and 5.33 Pa values.

  12. EDITORIAL: Non-polar and semipolar nitride semiconductors Non-polar and semipolar nitride semiconductors

    Science.gov (United States)

    Han, Jung; Kneissl, Michael

    2012-02-01

    Throughout the history of group-III-nitride materials and devices, scientific breakthroughs and technological advances have gone hand-in-hand. In the late 1980s and early 1990s, the discovery of the nucleation of smooth (0001) GaN films on c-plane sapphire and the activation of p-dopants in GaN led very quickly to the realization of high-brightness blue and green LEDs, followed by the first demonstration of GaN-based violet laser diodes in the mid 1990s. Today, blue InGaN LEDs boast record external quantum efficiencies exceeding 80% and the emission wavelength of the InGaN-based laser diode has been pushed into the green spectral range. Although these tremenduous advances have already spurred multi-billion dollar industries, there are still a number of scientific questions and technological issues that are unanswered. One key challenge is related to the polar nature of the III-nitride wurtzite crystal. Until a decade ago all research activities had almost exclusively concentrated on (0001)-oriented polar GaN layers and heterostructures. Although the device characteristics seem excellent, the strong polarization fields at GaN heterointerfaces can lead to a significant deterioration of the device performance. Triggered by the first demonstration non-polar GaN quantum wells grown on LiAlO2 by Waltereit and colleagues in 2000, impressive advances in the area of non-polar and semipolar nitride semiconductors and devices have been achieved. Today, a large variety of heterostructures free of polarization fields and exhibiting exceptional electronic and optical properties have been demonstrated, and the fundamental understanding of polar, semipolar and non-polar nitrides has made significant leaps forward. The contributions in this Semiconductor Science and Technology special issue on non-polar and semipolar nitride semiconductors provide an impressive and up-to-date cross-section of all areas of research and device physics in this field. The articles cover a wide range of

  13. Thick c-BN films deposited by radio frequency magnetron sputtering in argon/nitrogen gas mixture with additional hydrogen gas

    Science.gov (United States)

    Zhao, Yan; Gao, Wei; Xu, Bo; Li, Ying-Ai; Li, Hong-Dong; Gu, Guang-Rui; Yin, Hong

    2016-10-01

    The excellent physical and chemical properties of cubic boron nitride (c-BN) film make it a promising candidate for various industry applications. However, the c-BN film thickness restricts its practical applications in many cases. Thus, it is indispensable to develop an economic, simple and environment-friend way to synthesize high-quality thick, stable c-BN films. High-cubic-content BN films are prepared on silicon (100) substrates by radio frequency (RF) magnetron sputtering from an h-BN target at low substrate temperature. Adhesions of the c-BN films are greatly improved by adding hydrogen to the argon/nitrogen gas mixture, allowing the deposition of a film up to 5-μm thick. The compositions and the microstructure morphologies of the c-BN films grown at different substrate temperatures are systematically investigated with respect to the ratio of H2 gas content to total working gas. In addition, a primary mechanism for the deposition of thick c-BN film is proposed. Project supported by the National Natural Science Foundation of China (Grant Nos. 51572105, 61504046, and 51272224), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China, the Development and Reform Commission of Jilin Province, China (Grant No. 2015Y050), and the Scientific Research Foundation for the Returned Overseas of Jilin Province, China.

  14. Self-assembled heterogeneous argon/neon core-shell clusters studied by photoelectron spectroscopy.

    Science.gov (United States)

    Lundwall, M; Pokapanich, W; Bergersen, H; Lindblad, A; Rander, T; Ohrwall, G; Tchaplyguine, M; Barth, S; Hergenhahn, U; Svensson, S; Björneholm, O

    2007-06-01

    Clusters formed by a coexpansion process of argon and neon have been studied using synchrotron radiation. Electrons from interatomic Coulombic decay as well as ultraviolet and x-ray photoelectron spectroscopy were used to determine the heterogeneous nature of the clusters and the cluster structure. Binary clusters of argon and neon produced by coexpansion are shown to exhibit a core-shell structure placing argon in the core and neon in the outer shells. Furthermore, the authors show that 2 ML of neon on the argon core is sufficient for neon valence band formation resembling the neon solid. For 1 ML of neon the authors observe a bandwidth narrowing to about half of the bulk value.

  15. Surface Chemistry of Polymers Physical Adsorption of Nitrogen, Argon, Sulfur Dioxide and Neopentane on Polyvinylidene Fluoride

    OpenAIRE

    Houriet, Jean-Philippe; Ghiste, Patrick; Stoeckli, Fritz

    2007-01-01

    The adsorption of nitrogen, argon, sulfur dioxide and neopentane on polyvinylidene fluoride has been measured by static methods and by gas-solid chromatography. The polymer has a homogeneous surface of low energy, which is not significantly affected by heating.

  16. Surface modification of polypropylene using argon plasma: Statistical optimization of the process variables

    International Nuclear Information System (INIS)

    Low pressure plasma treatment using radiofrequency (rf) discharge of argon gas was employed to improve the hydrophilicity of polypropylene. The effects of argon plasma on the wettability, surface chemistry and surface morphology of polypropylene were studied using static contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Increase in surface energy of polypropylene was observed as a result of argon plasma treatment. SEM and AFM images revealed the increased surface roughness. A set of identified process variables (rf power, pressure, argon flow rate and time) were used in this study and were optimized using central composite design (CCD) of response surface methodology (RSM). A statistical model was developed to represent the surface energy in terms of the process variables mentioned above. Accuracy of the model was verified and found to be high.

  17. Simulations of argon accident scenarios in the ATLAS experimental cavern a safety analysis

    CERN Document Server

    Balda, F

    2002-01-01

    Some characteristic accidents in the ATLAS experimental cavern (UX15) are simulated by means of STAR-CD, a code using the "Finite-Volume" method. These accidents involve different liquid argon leaks from the barrel cryostat of the detector, thus causing the dispersion of the argon into the Muon Chamber region and the evaporation of the liquid. The subsequent temperature gradients and distribution of argon concentrations, as well as their evolution in time are simulated and discussed, with the purpose of analysing the dangers related to asphyxiation and to contact with cryogenic fluids for the working personnel. A summary of the theory that stands behind the code is also given. In order to validate the models, an experimental test on a liquid argon spill performed earlier is simulated, showing that the program is able to output reliable results. At the end, some safety-related recommendations are listed.

  18. Pose Measurement Performance of the Argon Relative Navigation Sensor Suite in Simulated Flight Conditions

    Science.gov (United States)

    Galante, Joseph M.; Eepoel, John Van; Strube, Matt; Gill, Nat; Gonzalez, Marcelo; Hyslop, Andrew; Patrick, Bryan

    2012-01-01

    Argon is a flight-ready sensor suite with two visual cameras, a flash LIDAR, an on- board flight computer, and associated electronics. Argon was designed to provide sensing capabilities for relative navigation during proximity, rendezvous, and docking operations between spacecraft. A rigorous ground test campaign assessed the performance capability of the Argon navigation suite to measure the relative pose of high-fidelity satellite mock-ups during a variety of simulated rendezvous and proximity maneuvers facilitated by robot manipulators in a variety of lighting conditions representative of the orbital environment. A brief description of the Argon suite and test setup are given as well as an analysis of the performance of the system in simulated proximity and rendezvous operations.

  19. Formation and characterization of magnesium bisozonide and carbonyl complexes in solid argon.

    Science.gov (United States)

    Wang, Guanjun; Gong, Yu; Zhang, Qingqing; Zhou, Mingfei

    2010-10-14

    The reactions of magnesium atoms with dioxygen and dioxygen/carbon monoxide mixture have been investigated by matrix isolation infrared absorption spectroscopy. Magnesium atoms react with dioxygen in solid argon to form the inserted MgO(2) molecules under UV excitation, which were previously characterized. Annealing allows the dioxygen molecules to diffuse and to react with MgO(2) and form the magnesium bisozonide complex, Mg(O(3))(2), which is proposed to be coordinated by two argon atoms in solid argon matrix. The Mg(O(3))(2)(Ar)(2) complex is characterized to have two equivalent side-on bonded ozonide ligands with a D(2h) symmetry. The coordinated argon atoms can be replaced by carbon monoxide to give the magnesium bisozonide dicarbonyl complex, Mg(O(3))(2)(CO)(2), a neutral magnesium carbonyl complex with CO binding to the Mg(2+) center. PMID:20857987

  20. Dynamic range compression in a liquid argon calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Cleland, W.E. [Univ. of Pittsburgh, PA (United States); Lissauer, D.; Radeka, V.; Rescia, S.; Takai, H. [Brookhaven National Lab., Upton, NY (United States); Wingerter-Seez, I. [LAPP, Annecy-le-Vieux (France)

    1996-12-31

    The anticipated range of particle energies at the LHC, coupled with the need for precision, low noise calorimetry makes severe demands on the dynamic range of the calorimeter readout. A common approach to this problem is to use shapers with two or more gain scales. In this paper, the authors describe their experience with a new approach in which a preamplifier with dynamic gain compression is used. An unavoidable consequence of dynamic gain adjustment is that the peaking time of the shaper output signal becomes amplitude dependent. The authors have carried out a test of such a readout system in the RD3 calorimeter, a liquid argon device with accordion geometry. The calibration system is used to determine both the gain of the individual channels as well as to map the shape of the waveform as a function of signal amplitude. A new procedure for waveform analysis, in which the fitted parameters describe the impulse response of the system, permits a straightforward translation of the calibration waveform to the waveform generated by a particle crossing the ionization gap. They find that the linearity and resolution of the calorimeter is equivalent to that obtained with linear preamplifiers, up to an energy of 200 GeV.

  1. Coherent set of electron cross sections for argon

    Science.gov (United States)

    Alves, L. L.; Ferreira, C. M.

    2011-10-01

    This paper presents a coherent set of electron impact cross sections for argon (elastic momentum-transfer, inelastic for the excitation of 37 levels Ar(4s,4p,3d,5p,4d,6s) and ionization), which was recently uploaded onto the LXcat IST-Lisbon database. The cross section set was validated by comparing calculated swarm parameters (electron mobility and characteristic energy) and rate coefficients (Townsend ionization coefficient and direct + cascade excitation coefficients to the 4s and 4p states) with available experimental data, for E / N = 10-4 - 100 Td and Tg = 300, 77 K. The validation procedure involves the solution to the homogeneous two-term electron Boltzmann equation, resorting to three different solvers: (i) IST-Lisbon's (ii) BOLSIG+ (v1.2) with LXcat; (iii) BOLSIG+ (v1.23). The results obtained with these solvers are compared to evidence the importance of certain numerical features related with both the energy-grid (number of points, grid-type and maximum energy value) and the interpolation scheme adopted for the cross sections. In particular, the latter can cause a 6% variation on the values of swarm parameters at intermediate E/Ns.

  2. An update of argon inelastic cross sections for plasma discharges

    International Nuclear Information System (INIS)

    This paper proposes a coherent set of electron impact inelastic cross sections for argon, based on recent experimental measurements. The updated set is validated by comparing calculated swarm parameters and rate coefficients (obtained by solving the two-term approximation electron Boltzmann equation) with available experimental data. This validation procedure is usually adopted when the cross section set is to be later used in plasma discharge modelling. Simulation results for the electron drift velocity and characteristic energy are in very good agreement with experimental values of these quantities. Calculations, using cross section sets proposed by different authors, of the total (direct + cascade) excitation coefficients to the 4s and 4p states, and of the Townsend ionization coefficient, show that the present set ensures the best overall agreement with measured values. The agreement is particularly good for the excitation coefficient to metastable 4s'[1/2]0 and the Townsend ionization coefficient, which are probably the most relevant electron macroscopic coefficients in the modelling of discharge plasmas

  3. Argon defect complexes in low energy Ar irradiated molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    van Veen, A.; Buters, W.T.M.; van der Kolk, G.J.; Caspers, L.M. (Interuniversitair Reactor Instituut, Delft (Netherlands)); Armstrong, T.R. (Victoria Univ., Wellington (New Zealand). Dept. of Physics)

    1982-03-15

    Thermal desorption spectrometry has been used to study the defects created in Mo irradiated along the <110> direction with Ar ions ranging in energy from 0.1 to 2 keV. In addition to monitoring the release of the implanted Ar, additional information has been obtained by decoration of the defects with low energy helium and subsequent monitoring of the helium release. The studies show evidence that the Ar can be trapped in both substitutional sites and in a configuration in which the Ar is associated with vacancies (ArVsub(n), n >= 2). Most of the Ar implanted at high energy is released at approx. equal to 1500 K by thermal vacancy assisted diffusion. Argon trapped closer to the surface is released at lower temperatures via at least three different surface related release mechanisms. Additional results are presented on the interaction of self interstitial atoms (introduced by 100 eV Xe bombardment) with the Ar defects. Substitutional Ar is found to convert to interstitial Ar which seems to be mobile at room temperature. The Ar-vacancy complexes are found to be reduced to substitutional Ar. The results of atomistic calculations of the release mechanisms will also be presented.

  4. Scintillation Light from Cosmic-Ray Muons in Liquid Argon

    CERN Document Server

    Whittington, Denver

    2014-01-01

    This paper reports the results of the first experiment to directly measure the properties of the scintillation light generated by minimum ionizing cosmic-ray muons in liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches, as well as for particle identification. The experiment was carried out at the TallBo facility at Fermilab using prototype light guides and electronics developed for the Long-Baseline Neutrino Experiment. Analysis of the time-resolved structure of the scintillation light from cosmic-ray muons gives $\\langle \\tau_{\\text{T}}\\rangle = 1.43 \\pm 0.04~\\text{(stat.)} \\pm 0.007~\\text{(sys.)}~\\mu$s for the triplet light decay time constant. The ratio of singlet to triplet light measured using surface-coated light guides is $R = 0.39 \\pm 0.01~\\text{(stat.)} \\pm 0.008~\\text{(sys.)}$. There is some evidence that this value is not consistent with $R$ for minimum ionizing electrons. However, the value for $...

  5. State-selective radiative recombination cross sections of argon ions

    International Nuclear Information System (INIS)

    The n-, (n,l)- and fine-structure level state-selective radiative recombinations (RR) cross sections of argon ions Ar18+,Ar13+,Ar7+ and Ar+ are obtained with the semi-classical Kramer formula, the relativistic self-consistent field (RSCF) method and the relativistic configuration interaction (RCI) method. It is found that for the highly charged ions with few electrons, the cross sections calculated with these three methods are in good agreement with each other. But as the number of electrons increases, the Kramer formula deviates from the RSCF and RCI results. For instance, when the energy of the incident electron is larger than 100 eV, the n-state selective cross sections of Ar7+ calculated from the Kramer formula are underestimated for more than 50%. The RSCF results are in general agreement with the RCI results. However, for the low charged ions, a clear distinction appears due to the strong configuration interaction, especially near the Cooper minimum. The n-resolved (n≤10) and total Maxwellian averaged rate coefficients are calculated, and the analytic fitting parameters are also provided. -- Highlights: ► The RR cross sections of Ar18+, Ar13+, Ar7+ and Ar+ are obtained. ► The Kramer formula, the relativistic self-consistent field and RCI methods are used. ► Results from three methods are compared with each other.

  6. Electronics calibration board for the ATLAS liquid argon calorimeters

    International Nuclear Information System (INIS)

    To calibrate the energy response of the ATLAS liquid argon calorimeter, an electronics calibration board has been designed; it delivers a signal whose shape is close to the calorimeter ionization current signal with amplitude up to 100 mA in 50 Ω with 16 bit dynamic range. The amplitude of this signal is designed to be uniform over all calorimeters channels, stable in time and with an integral linearity much better that the electronics readout. The various R and D phases and most of the difficulties met are discussed and illustrated by many measurements. The custom design circuits are described and the layout of the ATLAS calibration board presented. The procedure used to qualify the boards is explained and the performance obtained illustrated: a dynamic range up to 3 TeV in three energy scales with an integral linearity better than 0.1% in each of them, a response uniformity better than 0.2% and a stability better than 0.1%. The performance of the board is well within the ATLAS requirements. Finally, in situ measurements done on the ATLAS calorimeter are shown to validate these performances

  7. Methane from benzene in argon dielectric barrier discharge

    International Nuclear Information System (INIS)

    Highlights: ► Efficient on-line conversion of benzene to methane at room temperature. ► Absence of other H-atom donor suggests new type of chemistry. ► For parent loss > 90%, methane yield was ∼40% of limit due to H-atom availability. ► Surface moisture contributed ·OH radical for trace phenolic products’ formation. ► This method may emerge as an exploitable tactic for pollutants’ usable alterations. -- Abstract: A first-time account of direct, on-line, instantaneous and efficient chemical conversion of gas phase benzene to methane in argon Dielectric Barrier Discharge (DBD) is presented. In the absence of another overt hydrogen-donating source, potency of analogous parents toward methane generation is found to follow the order: benzene > toluene > p-xylene. Simultaneous production of trace amounts of phenolic surface deposits suggest (a) prompt decomposition of the parent molecules, including a large fraction yielding atomic transients (H-atom), (b) continuous and appropriate recombination of such parts, and (c) trace moisture in parent contributing ·OH radicals and additional H-atoms, which suitably react with the unreacted fraction of the parent, and also other intermediates. Results highlight Ar DBD to be a simple and exploitable technology for transforming undesirable hazardous aromatics to usable/useful low molecular weight open-chain products following the principles of green chemistry and engineering

  8. Optically Forbidden Excitations of 3s Electron of Argon by Fast Electron Impact

    Institute of Scientific and Technical Information of China (English)

    朱林繁; 成华东; 刘小井; 田鹏; 苑震生; 李文斌; 徐克尊

    2003-01-01

    The electron energy loss spectrum of argon in the energy region of 24.5-30.5eV was measured at 2.5 keV impact energy. The line profile parameters of the optically forbidden excitations of 3s-1ns (n = 4-6) and 3s-1nd (n = 3-7) of argon, I.e.,Eγ,Г,q and p,were determined.

  9. Benchmarking TPB-coated Light Guides for Liquid Argon TPC Light Detection Systems

    OpenAIRE

    Baptista, B.; Bugel, L.; Chiu, C; Conrad, J. M.; Ignarra, C. M.; Jones, B. J. P.; Katori, T.; Mufson, S.

    2012-01-01

    Scintillation light from liquid argon is produced at 128 nm and thus must be shifted to visible wavelengths in light detection systems used for Liquid Argon Time Projection Chambers (LArTPCs). To date, designs have employed tetraphenyl butadiene (TPB) coatings on photomultiplier tubes (PMTs) or plates placed in front of the PMTs. Recently, a new approach using TPB-coated light guides was proposed. In this paper, we show that the response of lightguides coated with TPB in a UV Transmitting (UV...

  10. TPB-coated Light Guides for Liquid Argon TPC Light Detection Systems

    CERN Document Server

    Ignarra, C M

    2013-01-01

    Light detection systems in Liquid Argon Time Projection Chambers (LArTPCs) require the detection of the 128 nm light produced during argon scintillation. Most detectors use Tetraphenyl Butadiene (TPB) to shift the wavelength of the light into a range visible to Photomultiplier Tubes (PMTs). These proceedings summarize characterizations of light-guides coated with a matrix of TPB in UV transmitting acrylic which are more compact than existing LArTPC light collection systems.

  11. TPB-coated light guides for liquid argon TPC light detection systems

    Science.gov (United States)

    Ignarra, C. M.

    2013-10-01

    Light detection systems in Liquid Argon Time Projection Chambers (LArTPCs) require the detection of the 128 nm light produced during argon scintillation. Most detectors use Tetraphenyl Butadiene (TPB) to shift the wavelength of the light into a range visible to Photomultiplier Tubes (PMTs). These proceedings summarize characterizations of light-guides coated with a matrix of TPB in UV transmitting acrylic which are more compact than existing LArTPC light collection systems.

  12. Effect of Ginkgo biloba on the lesions induced by retinal argon laser photocoagulation in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Clairambault, P.; Pairault, C.; Droy-Lefaix, M.T.; Magnier, B.; Magnier, M.

    1986-01-09

    In rabbits, retinal argon laser photocoagulation disrupts the arrangement of cell layers and produces interstitial edema. Photochemical and thermal energy is released with production of free oxygenated radicals that are responsible for destruction of cell membranes. Retinal argon laser photocoagulation in rabbits was used as a pharmacologic model to evaluate the protective effect of EGB 761 against membrane lesions and edema. As a strong free radicals scavengers, EGB 761 confirms its protective action on cells membranes and its anti-edema effect.

  13. Configurational Entropy,Diffusivity and Potential Energy Landscape in Liquid Argon

    Institute of Scientific and Technical Information of China (English)

    DUAN Yong-Ping; MA Cong-Xiao; LI Jia-Yun; LI Cong; WANG Dan; LI Mei-Li; SUN Min-Hua

    2009-01-01

    The configurational entropy, diffusion coefficient, dynamics and thermodynamics fragility indices of liquid argon are calculated using molecular dynamics simulations at two densities. The relationship between dynamics and thermodynamics properties is studied. The diffusion coefficient depends linearly on configurational entropy, which is consistent with the hypothesis of Adam-Gibbs. The consistence of dynamics and thermodynamics fragility indices demonstrates that dynamical behaviour is governed by thermodynamics behaviour in glass transition of liquid argon.

  14. Effect of Ginkgo biloba on the lesions induced by retinal argon laser photocoagulation in rabbits

    International Nuclear Information System (INIS)

    In rabbits, retinal argon laser photocoagulation disrupts the arrangement of cell layers and produces interstitial edema. Photochemical and thermal energy is released with production of free oxygenated radicals that are responsible for destruction of cell membranes. Retinal argon laser photocoagulation in rabbits was used as a pharmacologic model to evaluate the protective effect of EGB 761 against membrane lesions and edema. As a strong free radicals scavengers, EGB 761 confirms its protective action on cells membranes and its anti-edema effect

  15. A correction to Birks' Law in liquid argon ionization chamber simulations for highly ionizing particles

    International Nuclear Information System (INIS)

    We present a study of the performance of Birks' Law in liquid argon ionization chamber simulations as applied to highly ionizing particles, such as particles with multiple electric charges or with magnetic charge. We used Birks' Law to model recombination effects in a GEANT4 simulation of heavy ions in a liquid argon calorimeter. We then compared the simulation to published heavy-ion data to extract a highly ionizing particle correction to Birks' Law.

  16. LArGe: Background suppression using liquid argon (LAr) scintillation for 0$\

    CERN Document Server

    Marco, M D; Schönert, S

    2007-01-01

    Measurements with a bare p-type high purity germanium diode (HPGe) submerged in a 19 kg liquid argon (LAr) scintillation detector at MPIK Heidelberg are reported. The liquid argon--germanium system (LArGe) is operated as a 4$\\pi$ anti-Compton spectrometer to suppress backgrounds in the HPGe. This R&D is carried out in the framework of the GERDA experiment which searches for 0$\

  17. Discovery of photospheric argon in very hot central stars of planetary nebulae and white dwarfs

    CERN Document Server

    Werner, K; Kruk, J W

    2007-01-01

    We report the first discovery of argon in hot evolved stars and white dwarfs. We have identified the ArVII 1063.55A line in some of the hottest known (Teff=95000-110000 K) central stars of planetary nebulae and (pre-) white dwarfs of various spectral type. We determine the argon abundance and compare it to theoretical predictions from stellar evolution theory as well as from diffusion calculations. We analyze high-resolution spectra taken with the Far Ultraviolet Spectroscopic Explorer. We use non-LTE line-blanketed model atmospheres and perform line-formation calculations to compute synthetic argon line profiles. We find a solar argon abundance in the H-rich central star NGC1360 and in the H-deficient PG1159 star PG1424+535. This confirms stellar evolution modeling that predicts that the argon abundance remains almost unaffected by nucleosynthesis. For the DAO-type central star NGC7293 and the hot DA white dwarfs PG0948+534 and REJ1738+669 we find argon abundances that are up to three orders of magnitude sma...

  18. Numerical study of breakdown pattern induced by an intense microwave under nitrogen and argon gases

    Science.gov (United States)

    Takahashi, Masayuki; Ohnishi, Naofumi

    2016-07-01

    Filamentary plasma induced by microwave beam irradiation was reproduced in nitrogen and argon by combining fluid or particle plasma models with electromagnetic wave propagation. Transport coefficients used in the fluid model are estimated from particle simulation to maintain consistency of the breakdown structure between the fluid and particle models. A discrete structure was obtained using the one-dimensional (1D) fluid model, because a standing wave is generated in front of the plasma when the incident microwave beam is reflected by the overcritical plasma, which agrees with the breakdown structure obtained using the 1D particle model. A 2D plasma filament was also reproduced using the fluid model in nitrogen and argon. Reflection of the incident microwave in argon becomes stronger than that in nitrogen because of the denser argon plasma. Change in filament shape is induced in argon because the electric field is deformed at the plasma tip owing to stronger wave reflection from the neighboring filament. The propagation speed of the plasma front becomes larger in argon breakdown because of the larger ionization frequency and the larger diffusion coefficient.

  19. Condensed argon isentropic compression with ultrahigh magnetic field pressure: Experimental design. Post-shot report

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, A.I.; Boriskov, G.V.; Dolotenko, M.I. [All-Russian Research Inst. of Experimental Physics, Sarov (Russian Federation)] [and others

    1996-12-31

    This report continues the series of work devoted to experimental study of a high-dense condensed argon state. Remember that according to work of Kwon et. al., hexagonal close-packed structure is profitable in terms of energy rather than face-centered argon structure (stable with zero pressure). What is most interesting and intriguing here is the issue of possible argon metallization, when it is compressed up to the densities more than 9.17 g/cm{sup 3}. In the experiment of 1995 (the arrangement and data are described in a cited reference) the authors recorded appearance of conductivity in argon, which is non-conductive in the initial state, when it is compressed more than a factor of four. The peak value of argon specific conductivity recorded in this experiment did not exceed 10 (Ohm x cm){sup {minus}1}. This value of conductivity is characteristic of semiconductors, but not metals, which have 10{sup 4} (Ohm x cm){sup {minus}1}. At this stage of the work the main attention is paid to recording of argon conductive state and studying the possibilities of multiframed radiography of the sample in the compressed state.

  20. Low radioactivity argon dark matter search results from the DarkSide-50 experiment

    CERN Document Server

    Agnes, P; Albuquerque, I F M; Alexander, T; Alton, A K; Arisaka, K; Back, H O; Baldin, B; Biery, K; Bonfini, G; Bossa, M; Bottino, B; Brigatti, A; Brodsky, J; Budano, F; Bussino, S; Cadeddu, M; Cadonati, L; Cadoni, M; Calaprice, F; Canci, N; Candela, A; Cao, H; Cariello, M; Carlini, M; Catalanotti, S; Cavalcante, P; Chepurnov, A; Cocco, A G; Covone, G; Crippa, L; D'Angelo, D; D'Incecco, M; Davini, S; De Cecco, S; De Deo, M; De Vincenzi, M; Derbin, A; Devoto, 25 A; Di Eusanio, F; Di Pietro, G; Edkins, E; Empl, A; Fan, A; Fiorillo, G; Fomenko, K; Forster, G; Franco, D; Gabriele, F; Galbiati, C; Giganti, C; Goretti, A M; Granato, F; Grandi, L; Gromov, M; Guan, M; Guardincerri, Y; Hackett, B R; Herner, K; Hungerford, E V; Ianni, Al; Ianni, An; James, I; Jollet, C; Keeter, K; Kendziora, C L; Kobychev, V; Koh, G; Korablev, D; Korga, G; Kubankin, A; Li, X; Lissia, M; Lombardi, P; Luitz, S; Ma, Y; Machulin, I N; Mandarano, A; Mari, S M; Maricic, J; Marini, L; Martoff, C J; Meregaglia, A; Meyers, P D; Miletic, T; Milincic, R; Montanari, D; Monte, A; Montuschi, M; Monzani, M; Mosteiro, P; Mount, B J; Muratova, V N; Musico, P; Napolitano, J; Nelson, A; Odrowski, S; Orsini, M; Ortica, F; Pagani, L; Pallavicini, M; Pantic, E; Parmeggiano, S; Pelczar, K; Pelliccia, N; Perasso, S; Pocar, A; Pordes, S; Pugachev, D A; Qian, H; Randle, K; Ranucci, G; Razeto, A; Reinhold, B; Renshaw, A L; Romani, A; Rossi, B; Rossi, N; Rountree, D; Sablone, D; Saggese, P; Saldanha, R; Sands, W; Sangiorgio, S; Savarese, C; Segreto, E; Semenov, D A; Shields, E; Singh, P N; Skorokhvatov, M D; Smallcomb, M; Smirnov, O; Sotnikov, A; Stanford, C; Suvorov, Y; Tartaglia, R; Tatarowicz, J; Testera, G; Tonazzo, A; Trinchese, P; Unzhakov, E V; Vishneva, A; Vogelaar, B; Wada, M; Walker, S; Wang, H; Wang, Y; Watson, A W; Westerdale, S; Wilhelmi, J; Wojcik, M M; Xiang, X; Xu, J; Yang, C; Yoo, J; Zavatarelli, S; Zec, A; Zhong, W; Zhu, C; Zuzel, G

    2015-01-01

    The DarkSide-50 dark matter search reports the first results obtained using a target of low-radioactivity argon extracted from underground sources. The experiment is located at the Laboratori Nazionali del Gran Sasso and uses a two-phase time projection chamber as a detector. A total of 155 kg of low radioactivity argon has been obtained, and we have determined that underground argon is depleted in Ar-39 by a factor (1.4 +- 0.2) x 10^3 relative to atmospheric argon. The underground argon was also found to contain (2.05 +- 0.13) mBq/kg of Kr-85. We found no evidence for dark matter in the form of WIMPs in 70.9 live-days of data with a fiducial mass of (36.9 +- 0.6) kg. When combined with our preceding search with an atmospheric argon target, we set a 90 % C.L. upper limit on the WIMP-nucleon spin-independent cross section of 2.0 x 10^-44 cm^2 (8.6 x 10^-44 cm^2, 8.0 x 10^-43 cm^2 ) for a WIMP mass of 100 GeV/c^2 (1 TeV/c^2 , 10 TeV/c^2 ).

  1. Results from the first use of low radioactivity argon in a dark matter search

    Energy Technology Data Exchange (ETDEWEB)

    Agnes, P. [Universite Paris Diderot (France). et al.

    2016-04-08

    Liquid argon is a bright scintillator with potent particle identification properties, making it an attractive target for direct-detection dark matter searches. The DarkSide-50 dark matter search here reports the first WIMP search results obtained using a target of low-radioactivity argon. DarkSide-50 is a dark matter detector, using two-phase liquid argon time projection chamber, located at the Laboratori Nazionali del Gran Sasso. The underground argon is shown to contain Ar-39 at a level reduced by a factor (1.4 +- 0.2) x 103 relative to atmospheric argon. We report a background-free null result from (2616 +- 43) kg d of data, accumulated over 70.9 live-days. When combined with our previous search using an atmospheric argon, the 90 % C.L. upper limit on the WIMP-nucleon spin-independent cross section based on zero events found in the WIMP search regions, is 2.0 x 10-44 cm2 (8.6 x 10-44 cm2, 8.0 x 10-43 cm2) for a WIMP mass of 100 GeV/c2 (1 TeV/c2 , 10 TeV/c2).

  2. Electroless plating of thin gold films directly onto silicon nitride thin films and into micropores.

    Science.gov (United States)

    Whelan, Julie C; Karawdeniya, Buddini Iroshika; Bandara, Y M Nuwan D Y; Velleco, Brian D; Masterson, Caitlin M; Dwyer, Jason R

    2014-07-23

    A method to directly electrolessly plate silicon-rich silicon nitride with thin gold films was developed and characterized. Films with thicknesses coating planar, curved, and line-of-sight-obscured silicon nitride surfaces. PMID:24999923

  3. Evaluation of plasma nitriding efficiency of titanium alloys for medical applications

    OpenAIRE

    Frączek, T.; Olejnik, M.; Tokarz, A.

    2009-01-01

    The surface layers obtained on selected titanium alloys, used in medicine, by the nitriding under glow discharge condition were investigated. The results concern of: α- titanium alloy Grade 2 and α + β alloys Grade 5 and Grade 5 ELI nitrided in temperature below 873 K. The nitriding experiments were performed in a current glow-discharge furnace JON-600 with assisting of unconventional methods. After nitriding surface layers were characterised by surface microhardness measuremen...

  4. Molecular dynamics studies of the bonding properties of amorphous silicon nitride coatings on crystalline silicon

    OpenAIRE

    Butler, K.T.; Lamers, M.P.W.E.; Weeber, A. W.; Harding, J. H.

    2011-01-01

    In this paper we present molecular dynamics simulations of silicon nitride, both in bulk and as an interface to crystalline silicon. We investigate, in particular, the bonding structure of the silicon nitride and analyze the simulations to search for de- fective geometries which have been identified as potential charge carrier traps when silicon nitride forms an interface with silicon semiconductors. The simulations reveal how the bonding patterns in silicon nitride are dependent upon the sto...

  5. Effect of Treatment Temperature on Iron Nitride Foils Irradiated with Nitrogen Plasma

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We investigated the effect of treatment temperature on the magnetic property of iron nitride foils irradiated with nitrogen plasma. The iron nitride foils irradiated with nitrogen plasma were composed of ε-Fe2~3N, γ′-Fe4N and γ nitrogen austenite in α-Fe of the matrix. The saturation magnetization of the iron nitride foils decreased with increasing the surface temperature. The coercive force of the iron nitride foils increased with increasing the surface temperature.

  6. Technical assistance for development of thermally conductive nitride filler for epoxy molding compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Song, Kee Chan; Jung, In Ha

    2005-07-15

    Technical assistance was carried out to develop nitride filler for thermally conductive epoxy molding compounds. Carbothermal reduction method was used to fabricate silicon nitride powder from mixtures of silica and graphite powders. Microstructure and crystal structure were observed by using scanning electron microscopy and x-ray diffraction technique. Thermal properties of epoxy molding compounds containing silicon nitride were measured by using laser flash method. Fabrication process of silicon nitride nanowire was developed and was applied to a patent.

  7. DFT Studies on Electronic Structures of Boro-Nitride-Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    YAN Ming; HUANG Chun-Hui

    2005-01-01

    In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nanotubes were calculated by DFT/ROB3LYP method. By analyzing the energy gap, density of electronic state and bonding maps of atoms, the conductive properties of Boro-Nitride-Carbon nanotubes were obtained, and compared with those of carbon nanotubes and other Boro-Nitride nanotubes.

  8. Nitriding of iron-based alloys : residual stresses and internal strain fields

    OpenAIRE

    Vives Díaz, Nicolás

    2007-01-01

    Different iron-chromium alloys (4, 8, 13 and 20 wt.% Cr) were nitrided in NH3/H2 gas mixtures at 580 ºC. The nitrided microstructure was investigated by X-ray diffraction, light microscopy, hardness measurements and scanning electron microscopy. Composition depth-profiles of the nitrided zone were determined by electron probe microanalysis. Various microstructures develop, depending on the nitriding conditions and the alloy composition (chromium content). The initial development of coherent, ...

  9. Microstructure and Mechanical Propertiesof a Nitride-Strengthened Reduced ActivationFerritic/Martensitic Steel

    OpenAIRE

    Zhou, Qiangguo; Zhang, Wenfeng; Yan, Wei; Wang, Wei; SHA, WEI; Shan, Yiyin; Yang, Ke

    2012-01-01

    Nitride-strengthened reduced activation ferritic/martensitic (RAFM) steels are developed taking advantage of the high thermal stability of nitrides. In the current study, the microstructure and mechanical properties of a nitride-strengthened RAFM steel with improved composition were investigated. Fully martensitic microstructure with fine nitrides dispersion was achieved in the steel. In all, 1.4 pct Mn is sufficient to suppress delta ferrite and assure the steel of the full martensitic micro...

  10. Corrosion resistance of zirconium oxynitride coatings deposited via DC unbalanced magnetron sputtering and spray pyrolysis-nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Cubillos, G.I., E-mail: gcubillos@unal.edu.co [Department of Chemistry, Group of Materials and Chemical Processes, Universidad Nacional de Colombia, Av. Cra. 30 No 45-03, Bogotá (Colombia); Bethencourt, M., E-mail: manuel.bethencourt@uca.es [Department of Materials Science, Metallurgy Engineering and Inorganic Chemistry, International Campus of Excellence of the Sea - CEI-MAR, University of Cadiz, Avda. República Saharaui s/n, 11510 Puerto Real, Cádiz (Spain); Olaya, J.J., E-mail: jjolayaf@unal.edu.co [Faculty of Engineering, Group of Materials and Chemical Processes, Universidad Nacional de Colombia, Av. Cra. 30 No 45-03, Bogotá (Colombia)

    2015-02-01

    Highlights: • New ZrO{sub x}N{sub y} films were deposited on stainless steel 316L using PSY-N and UBMS. • ZrO{sub x}N{sub y} rhombohedral polycrystalline film grew with PSY-N. • Zr{sub 2}ON{sub 2} crystalline structures, mostly oriented along the (2 2 2) plane, grew with UBMS. • Layers improved corrosion behavior in NaCl media, especially those deposited by UBMS. - Abstract: ZrO{sub x}N{sub y}/ZrO{sub 2} thin films were deposited on stainless steel using two different methods: ultrasonic spray pyrolysis-nitriding (SPY-N) and the DC unbalanced magnetron sputtering technique (UBMS). Using the first method, ZrO{sub 2} was initially deposited and subsequently nitrided in an anhydrous ammonia atmosphere at 1023 K at atmospheric pressure. For UBMS, the film was deposited in an atmosphere of air/argon with a Φair/ΦAr flow ratio of 3.0. Structural analysis was carried out through X-ray diffraction (XRD), and morphological analysis was done through scanning electron microscopy (SEM) and atomic force microscopy (AFM). Chemical analysis was carried out using X-ray photoelectron spectroscopy (XPS). ZrO{sub x}N{sub y} rhombohedral polycrystalline film was produced with spray pyrolysis-nitriding, whereas using the UBMS technique, the oxynitride films grew with cubic Zr{sub 2}ON{sub 2} crystalline structures preferentially oriented along the (2 2 2) plane. Upon chemical analysis of the surface, the coatings exhibited spectral lines of Zr3d, O1s, and N1s, characteristic of zirconium oxynitride/zirconia. SEM analysis showed the homogeneity of the films, and AFM showed morphological differences according to the deposition technique of the coatings. Zirconium oxynitride films enhanced the stainless steel's resistance to corrosion using both techniques. The protective efficacy was evaluated using electrochemical techniques based on linear polarization (LP). The results indicated that the layers provide good resistance to corrosion when exposed to chloride

  11. Turbostratic boron nitride coated on high-surface area metal oxide templates

    DEFF Research Database (Denmark)

    Klitgaard, Søren Kegnæs; Egeblad, Kresten; Brorson, M.;

    2007-01-01

    Boron nitride coatings on high-surface area MgAl2O4 and Al2O3 have been synthesized and characterized by transmission electron microscopy and by X-ray powder diffraction. The metal oxide templates were coated with boron nitride using a simple nitridation in a flow of ammonia starting from ammoniu...

  12. Mathematical Models and Computer Simulation of Nitrogen Concentration Profiles in Pulse Plasma Nitrided Layers

    Institute of Scientific and Technical Information of China (English)

    Mufu YAN; Qingchang MENG; Jihong YAN

    2003-01-01

    Two materials, pure Fe and pure Al, were nitrided in a pulse plasma nitriding facility. The nitrogen profiles in surface layers and the surface phase structures of specimens nitrided at 500℃ for 8 h for Fe and for 6 h for Al were measured using the glow

  13. UN{sub 2−x} layer formed on uranium metal by glow plasma nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Long, Zhong [China Academy of Engineering Physics, P.O. Box 919-71, Mianyang 621907 (China); Hu, Yin [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China); Chen, Lin [China Academy of Engineering Physics, P.O. Box 919-71, Mianyang 621907 (China); Luo, Lizhu [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China); Liu, Kezhao, E-mail: liukz@hotmail.com [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China); Lai, Xinchun, E-mail: lai319@yahoo.com [Science and Technology on Surface Physics and Chemistry Laboratory, P.O. Box 718-35, Mianyang 621907 (China)

    2015-01-25

    Highlights: • We used a very simple method to prepare nitride layer on uranium metal surface. • This modified layer is nitrogen-rich nitride, which should be written as UN{sub 2−x}. • TEM images show the nitride layer is composed of nano-sized grains. • XPS analysis indicates there is uranium with abnormal low valence in the nitride. - Abstract: Glow plasma nitriding is a simple and economical surface treatment method, and this technology was used to prepare nitride layer on the surface of uranium metal with thickness of several microns. The composition and structure of the nitride layer were analyzed by AES and XRD, indicating that this modified layer is nitrogen-rich uranium nitride, which should be written as UN{sub 2−x}. TEM images show the nitride layer is composed of nano-sized grains, with compact structure. And XPS analysis indicates there is uranium with abnormal low valence existing in the nitride. After the treated uranium storage in air for a long time, oxygen just entered the surface several nanometers, showing the nitride layer has excellent oxidation resistance. The mechanism of nitride layer formation and low valence uranium appearance is discussed.

  14. Corrosion behaviour of the 42CrMo4 Steel Nitrided by Plasma

    Directory of Open Access Journals (Sweden)

    Okba Belahssen

    2014-01-01

    Full Text Available This paper presents corrosion behaviour of alloy 42CrMo4 steel nitrided by plasma. Different samples were tested: untreated and plasma nitrided samples. The corrosion behaviour was evaluated by electrochemical techniques (potentiodynamic curves and electrochemical impedance spectroscopy. The corrosion tests were carried out in acid chloride solution 1M. The best corrosion protection was observed for samples nitrided.

  15. Inhaled 45–50% argon augments hypothermic brain protection in a piglet model of perinatal asphyxia

    Science.gov (United States)

    Broad, Kevin D.; Fierens, Igor; Fleiss, Bobbi; Rocha-Ferreira, Eridan; Ezzati, Mojgan; Hassell, Jane; Alonso-Alconada, Daniel; Bainbridge, Alan; Kawano, Go; Ma, Daqing; Tachtsidis, Ilias; Gressens, Pierre; Golay, Xavier; Sanders, Robert D.; Robertson, Nicola J.

    2016-01-01

    Cooling to 33.5 °C in babies with neonatal encephalopathy significantly reduces death and disability, however additional therapies are needed to maximize brain protection. Following hypoxia–ischemia we assessed whether inhaled 45–50% Argon from 2–26 h augmented hypothermia neuroprotection in a neonatal piglet model, using MRS and aEEG, which predict outcome in babies with neonatal encephalopathy, and immunohistochemistry. Following cerebral hypoxia–ischemia, 20 Newborn male Large White piglets < 40 h were randomized to: (i) Cooling (33 °C) from 2–26 h (n = 10); or (ii) Cooling and inhaled 45–50% Argon (Cooling + Argon) from 2–26 h (n = 8). Whole-brain phosphorus-31 and regional proton MRS were acquired at baseline, 24 and 48 h after hypoxia–ischemia. EEG was monitored. At 48 h after hypoxia–ischemia, cell death (TUNEL) was evaluated over 7 brain regions. There were no differences in body weight, duration of hypoxia–ischemia or insult severity; throughout the study there were no differences in heart rate, arterial blood pressure, blood biochemistry and inotrope support. Two piglets in the Cooling + Argon group were excluded. Comparing Cooling + Argon with Cooling there was preservation of whole-brain MRS ATP and PCr/Pi at 48 h after hypoxia–ischemia (p < 0.001 for both) and lower 1H MRS lactate/N acetyl aspartate in white (p = 0.03 and 0.04) but not gray matter at 24 and 48 h. EEG background recovery was faster (p < 0.01) with Cooling + Argon. An overall difference between average cell-death of Cooling versus Cooling + Argon was observed (p < 0.01); estimated cells per mm2 were 23.9 points lower (95% C.I. 7.3–40.5) for the Cooling + Argon versus Cooling. Inhaled 45–50% Argon from 2–26 h augmented hypothermic protection at 48 h after hypoxia–ischemia shown by improved brain energy metabolism on MRS, faster EEG recovery and reduced cell death on TUNEL. Argon may provide a cheap and practical therapy

  16. Modelling steel’s homogenization during argon purging

    Directory of Open Access Journals (Sweden)

    J. Pieprzyca

    2012-12-01

    Full Text Available Purpose: One of the primary tasks that put the steel producers to the test is to reduce production costs while maintaining high quality. This objective is achieved among others through the optimization of conducted technological processes. Commonly used technology of steel homogenization with inert gases is an important stage in the production of steel in which that objective can be accomplished.Design/methodology/approach: Tests of hydrodynamic processes occurring during the steel blowing with inert gases process directly in industrial conditions is very difficult or impossible. Therefore, as the primary research method physical modelling was used. In order to carry out the tests described in the article a physical model of the station for the argon purging was used that is working at the VSB-TU, Department of Metallurgy and Foundry in Ostrava.Findings: As a result the study provided values for the investigated process and determined the appropriate location of the gas-permeable fittings in steelmaking ladle’s bottom plug. This allows to obtain the required conditions for the steel mixing in the entire volume of ladle’s workspace.Research limitations/implications: Tests presented in the article were carried out in the VSB-TU in Ostrava. Due to this fact some research limitations occurs that applies to localization and physical model’s specific construction. Therefore, as a result of cooperation between VSB-TU in Ostrava and the Silesian University of Technology will be carried out the construction of the new research station in Katowice.Practical implications: The results of the research constitute the basis to make changes that will allow the optimization to so far used purge of steel technology.Originality/value: The results presented in the article are addressed to the steel producers and it allows to optimize on-going steel homogenization process that takes place in the ladle

  17. Scintillation light from cosmic-ray muons in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Whittington, Denver Wade [Indiana Univ., Bloomington, IN (United States). Physics Dept.; Mufson, S. [Indiana Univ., Bloomington, IN (United States). Astronomy Dept.; Howard, B. [Indiana Univ., Bloomington, IN (United States). Physics Dept.

    2016-05-01

    This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a physically-motivated model. Both models find tT = 1:52 ms for the decay time constant of the Ar 2 triplet state. These models also show that the identification of the “early” light fraction in the phenomenological model, FE 25% of the signal, with the total light from singlet decays is an underestimate. The total fraction of singlet light is FS 36%, where the increase over FE is from singlet light emitted by the wavelength shifter through processes with long decay constants. The models were further used to compute the experimental particle identification parameter Fprompt, the fraction of light coming in a short time window after the trigger compared with the light in the total recorded waveform. The models reproduce quite well the typical experimental value 0.3 found by dark matter and double b-decay experiments, which suggests this parameter provides a robust metric for discriminating electrons and muons from more heavily ionizing particles.

  18. Scintillation Light from Cosmic-Ray Muons in Liquid Argon

    Energy Technology Data Exchange (ETDEWEB)

    Whittington, Denver Wade [Indiana U.; Mufson, S. [Indiana U., Bloomington, Dept. Astron.; Howard, B. [Indiana U.

    2015-11-13

    This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a physically-motivated model. Both models find tT = 1:52 ms for the decay time constant of the Ar 2 triplet state. These models also show that the identification of the “early” light fraction in the phenomenological model, FE 25% of the signal, with the total light from singlet decays is an underestimate. The total fraction of singlet light is FS 36%, where the increase over FE is from singlet light emitted by the wavelength shifter through processes with long decay constants. The models were further used to compute the experimental particle identification parameter Fprompt, the fraction of light coming in a short time window after the trigger compared with the light in the total recorded waveform. The models reproduce quite well the typical experimental value 0.3 found by dark matter and double b-decay experiments, which suggests this parameter provides a robust metric for discriminating electrons and muons from more heavily ionizing particles.

  19. Scintillation light from cosmic-ray muons in liquid argon

    Science.gov (United States)

    Whittington, D.; Mufson, S.; Howard, B.

    2016-05-01

    This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a composite model. Both models find τT = 1.52 μs for the decay time constant of the Ar2* triplet state. These models also show that the identification of the ``early'' light fraction in the phenomenological model, FE ≈ 25% of the signal, with the total light from singlet decays is an underestimate. The total fraction of singlet light is FS ≈ 36%, where the increase over FE is from singlet light emitted by the wavelength shifter through processes with long decay constants. The models were further used to compute the experimental particle identification parameter Fprompt, the fraction of light coming in a short time window after the trigger compared with the light in the total recorded waveform. The models reproduce quite well the typical experimental value ~0.3 found by dark matter and double β-decay experiments, which suggests this parameter provides a robust metric for discriminating electrons and muons from more heavily ionizing particles.

  20. Effective Duration of Gas Nitriding Process on AISI 316L for the Formation of a Desired Thickness of Surface Nitrided Layer

    Directory of Open Access Journals (Sweden)

    Mahmoud Hassan R. S.

    2014-07-01

    Full Text Available High temperature gas nitriding performed on AISI 316L at the temperature of 1200°C. The microstructure of treated AISI 316L samples were observed to identify the formation of the microstructure of nitrided surface layer. The grain size of austenite tends to be enlarged when the nitriding time increases, but the austenite single phase structure is maintained even after the long-time solution nitriding. Using microhardness testing, the hardness values drop to the center of the samples. The increase in surface hardness is due to the high nitrogen concentration at or near the surface. At 245HV, the graph of the effective duration of nitriding process was plotted to achieve the maximum depth of nitrogen diffuse under the surface. Using Sigma Plot software best fit lines of the experimental result found and plotted to find out effective duration of nitriding equation as Y=1.9491(1-0.7947x, where Y is the thickness of nitrided layer below the surface and X is duration of nitriding process. Based on this equation, the duration of gas nitriding process can be estimated to produce desired thickness of nitrided layer.

  1. The melting parameters of high-temperature nonmetallic nitrides

    International Nuclear Information System (INIS)

    The ranges of temperatures and pressures for the existence of condensed boron, aluminum, and silicon nonmetallic nitrides in thermodynamic equilibrium with an ambient gas were calculated on the basis of reference data. The melting parameters of the high-temperature nitrides mentioned above were investigated experimentally in the nitrogen pressure range of 5200 MPa. The 99% purity nitride samples were prepared in the form of 4 x 4-mm plates with a thickness of 1 mm. The surfaces of samples were heated with stationary laser beam and analyzed by X-ray technique. The brightness temperature of nonmetallic nitrides was measured at 0.633-μm wavelength using the optical pyrometry method. The apparent melting temperatures were found from the analysis of heating and cooling thermograms. Based on the available literature data on normal spectral emmissivity, the true melting temperatures of nonmetallic nitrides were estimated as 3370 K for BN, 3025 K for AlN, and 2775 K for Si3N4

  2. Formation and nitridation of vanadium-aluminum intermetallic compounds.

    Science.gov (United States)

    Lewalter, H; Bock, W; Kolbesen, B O

    2002-10-01

    V(5)Al(8) and V(3)Al intermetallics have been formed by interdiffusion, by annealing of sputtered V/Al-multilayers at 700 degrees C in vacuo; sapphire (102) was used as substrate. The V/Al intermetallics were nitridated in NH(3) at 900 degrees C for 1 min by RTP (rapid thermal processing). The samples were investigated with XRD (X-ray diffraction), SNMS (secondary neutral mass spectrometry), and AFM (atomic force microscopy). A 5-10 nm thick AlN film (001 textured) was formed by nitridation of V(5)Al(8) (110 textured) and 2-3% nitrogen was incorporated in the V(5)Al(8) bulk. Nitridation of V(3)Al resulted in the formation of VN and AlN. Direct nitridation of V/Al-multilayers showed that near the surface nitridation is faster than intermixing of the V and Al layers. The capability of VN as diffusion barrier for Al could also be shown. PMID:12397502

  3. Surface properties of nitrided layer on AISI 316L austenitic stainless steel produced by high temperature plasma nitriding in short time

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yang, E-mail: metalytu@163.com [Department of Materials Science and Engineering, Yantai University, Qingquan Road 32, Yantai 264005 (China); Wang, Zhuo [Department of Materials Science and Engineering, Yantai University, Qingquan Road 32, Yantai 264005 (China); Wang, Liang [Department of Materials Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian 116026 (China)

    2014-04-01

    Graphical abstract: - Highlights: • The 8 μm nitrided layer was produced on the surface of AISI 316L stainless steel by plasma nitrided at high temperatures (540 °C) within 1 h. • The nitrided layer consisted of nitrogen expanded austenite and possibly a small amount of free-CrN and iron nitrides. • It could critically reduce processing time compared with low temperature nitriding. • High temperature plasma nitriding could improve pitting corrosion resistance of the substrate in 3.5% NaCl solution. - Abstract: It has generally been believed that the formation of the S phase or expanded austenite γ{sub N} with enough thickness depends on the temperature (lower than 480 °C) and duration of the process. In this work, we attempt to produce nitrogen expanded austenite layer at high temperature in short time. Nitriding of AISI 316L austenitic stainless steel was carried out at high temperatures (>520 °C) for times ranging from 5 to 120 min. The microstructures, chemical composition, the thickness and the morphology of the nitrided layer, as well as its surface hardness, were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, optical microscopy, scanning electron microscopy, and microhardness tester. The corrosion properties of the untreated and nitrided samples were evaluated using anodic polarization tests in 3.5% NaCl solution. The results confirmed that nitrided layer was shown to consist of γ{sub N} and a small amount of free-CrN and iron nitrides. High temperature plasma nitriding not only increased the surface hardness but also improved the corrosion resistance of the austenitic stainless steel, and it can critically reduce processing time compared with low temperature nitriding.

  4. Preparation of graphitic carbon nitride by electrodeposition

    Institute of Scientific and Technical Information of China (English)

    LI Chao; CAO Chuanbao; ZHU Hesun

    2003-01-01

    The CNx thin film was deposited on Si(100) substrate from a saturated acetone solution of cyanuric trichloride and melamine (cyanuric trichloride/melamine=1︰1.5) at room temperature. X-ray diffraction (XRD) results showed that the diffraction peaks in the pattern coincided well with those of graphite-like carbon nitride calculated in the literature. The lattice constants (a=4.79 A, c=6.90 A) for g-C3N4 matched with those of ab initio calculations (a=4.74 A, c=6.72 A) quite well. X-ray photoelectron spectroscopy (XPS) measurements indicated that the elements in the deposited films were mostly of C and N (N/C=0.75), and N (400.00 eV) bonded with C (287.72 eV) in the form of six-member C3N3 ring. The peaks at 800 cm-1, 1310 cm-1 and 1610 cm-1 in the Fourier transform infrared (FTIR) spectrum indicated that triazine ring existed in the product. These results demonstrated that crystalline g-C3N4 was obtained in the CNx film.

  5. Fluorescent lighting with aluminum nitride phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, Nerine J.; Payne, Stephen A.; Seeley, Zachary M.; Srivastava, Alok M.

    2016-05-10

    A fluorescent lamp includes a glass envelope; at least two electrodes connected to the glass envelope; mercury vapor and an inert gas within the glass envelope; and a phosphor within the glass envelope, wherein the phosphor blend includes aluminum nitride. The phosphor may be a wurtzite (hexagonal) crystalline structure Al.sub.(1-x)M.sub.xN phosphor, where M may be drawn from beryllium, magnesium, calcium, strontium, barium, zinc, scandium, yttrium, lanthanum, cerium, praseodymium, europium, gadolinium, terbium, ytterbium, bismuth, manganese, silicon, germanium, tin, boron, or gallium is synthesized to include dopants to control its luminescence under ultraviolet excitation. The disclosed Al.sub.(1-x)M.sub.xN:Mn phosphor provides bright orange-red emission, comparable in efficiency and spectrum to that of the standard orange-red phosphor used in fluorescent lighting, Y.sub.2O.sub.3:Eu. Furthermore, it offers excellent lumen maintenance in a fluorescent lamp, and does not utilize "critical rare earths," minimizing sensitivity to fluctuating market prices for the rare earth elements.

  6. Hexagonal boron-nitride nanomesh magnets

    Science.gov (United States)

    Ohata, C.; Tagami, R.; Nakanishi, Y.; Iwaki, R.; Nomura, K.; Haruyama, J.

    2016-09-01

    The formation of magnetic and spintronic devices using two-dimensional (2D) atom-thin layers has attracted attention. Ferromagnetisms (FMs) arising from zigzag-type atomic structure of edges of 2D atom-thin materials have been experimentally observed in graphene nanoribbons, hydrogen (H)-terminated graphene nanomeshes (NMs), and few-layer oxygen (O)-terminated black phosphorus NMs. Herein, we report room-temperature edge FM in few-layer hexagonal boron-nitride (hBN) NMs. O-terminated hBNNMs annealed at 500 °C show the largest FM, while it completely disappears in H-terminated hBNNMs. When hBNNMs are annealed at other temperatures, amplitude of the FM significantly decreases. These are highly in contrast to the case of graphene NMs but similar to the cases of black phosphorus NM and suggest that the hybridization of the O atoms with B(N) dangling bonds of zigzag pore edges, formed at the 500 °C annealing, strongly contribute to this edge FM. Room-temperature FM realizable only by exposing hBNNMs into air opens the way for high-efficiency 2D flexible magnetic and spintronic devices without the use of rare magnetic elements.

  7. Polymeric photocatalysts based on graphitic carbon nitride.

    Science.gov (United States)

    Cao, Shaowen; Low, Jingxiang; Yu, Jiaguo; Jaroniec, Mietek

    2015-04-01

    Semiconductor-based photocatalysis is considered to be an attractive way for solving the worldwide energy shortage and environmental pollution issues. Since the pioneering work in 2009 on graphitic carbon nitride (g-C3N4) for visible-light photocatalytic water splitting, g-C3N4 -based photocatalysis has become a very hot research topic. This review summarizes the recent progress regarding the design and preparation of g-C3N4 -based photocatalysts, including the fabrication and nanostructure design of pristine g-C3N4 , bandgap engineering through atomic-level doping and molecular-level modification, and the preparation of g-C3N4 -based semiconductor composites. Also, the photo-catalytic applications of g-C3N4 -based photocatalysts in the fields of water splitting, CO2 reduction, pollutant degradation, organic syntheses, and bacterial disinfection are reviewed, with emphasis on photocatalysis promoted by carbon materials, non-noble-metal cocatalysts, and Z-scheme heterojunctions. Finally, the concluding remarks are presented and some perspectives regarding the future development of g-C3N4 -based photocatalysts are highlighted.

  8. Plasmonic enhancement of photoluminescence from aluminium nitride

    Science.gov (United States)

    Flynn, Chris; Stewart, Matthew

    2016-03-01

    Aluminium nitride (AlN) films were grown on c-plane sapphire wafers by molecular beam epitaxy (MBE) under aluminium-rich conditions. The excess aluminium (Al) accumulated on the surface of the films as micro-scale droplets 1-10 μm in size, and as Al nanoparticles with diameters in the range 10-110 nm. Photoluminescence (PL) measurements were performed on the AlN samples using a 193 nm Excimer laser as the excitation source. Prior to PL measurements the wafers were cleaved in half. One half of each wafer was submitted to a 10 min treatment in H3PO4 heated to 70 °C to remove the excess Al from the film surface. The remaining half was left in the as-deposited condition. The mean intensities of the near-band-edge PL peaks of the as-deposited samples were 2.0-3.4 times higher compared to the samples subjected to the H3PO4 Al-removal treatment. This observation motivated calculations to determine the optimal Al surface nanosphere size for plasmonic enhancement of PL from AlN. The PL enhancement was found to peak for an Al nanosphere radius of 15 nm, which is within the range of the experimentally-observed Al nanoparticle sizes.

  9. Fully CMOS-compatible titanium nitride nanoantennas

    International Nuclear Information System (INIS)

    CMOS-compatible fabrication of plasmonic materials and devices will accelerate the development of integrated nanophotonics for information processing applications. Using low-temperature plasma-enhanced atomic layer deposition (PEALD), we develop a recipe for fully CMOS-compatible titanium nitride (TiN) that is plasmonic in the visible and near infrared. Films are grown on silicon, silicon dioxide, and epitaxially on magnesium oxide substrates. By optimizing the plasma exposure per growth cycle during PEALD, carbon and oxygen contamination are reduced, lowering undesirable loss. We use electron beam lithography to pattern TiN nanopillars with varying diameters on silicon in large-area arrays. In the first reported single-particle measurements on plasmonic TiN, we demonstrate size-tunable darkfield scattering spectroscopy in the visible and near infrared regimes. The optical properties of this CMOS-compatible material, combined with its high melting temperature and mechanical durability, comprise a step towards fully CMOS-integrated nanophotonic information processing

  10. Fully CMOS-compatible titanium nitride nanoantennas

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Justin A., E-mail: jabriggs@stanford.edu [Department of Applied Physics, Stanford University, 348 Via Pueblo Mall, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305 (United States); Naik, Gururaj V.; Baum, Brian K.; Dionne, Jennifer A. [Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 94305 (United States); Petach, Trevor A.; Goldhaber-Gordon, David [Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305 (United States)

    2016-02-01

    CMOS-compatible fabrication of plasmonic materials and devices will accelerate the development of integrated nanophotonics for information processing applications. Using low-temperature plasma-enhanced atomic layer deposition (PEALD), we develop a recipe for fully CMOS-compatible titanium nitride (TiN) that is plasmonic in the visible and near infrared. Films are grown on silicon, silicon dioxide, and epitaxially on magnesium oxide substrates. By optimizing the plasma exposure per growth cycle during PEALD, carbon and oxygen contamination are reduced, lowering undesirable loss. We use electron beam lithography to pattern TiN nanopillars with varying diameters on silicon in large-area arrays. In the first reported single-particle measurements on plasmonic TiN, we demonstrate size-tunable darkfield scattering spectroscopy in the visible and near infrared regimes. The optical properties of this CMOS-compatible material, combined with its high melting temperature and mechanical durability, comprise a step towards fully CMOS-integrated nanophotonic information processing.

  11. Conductivity of materials made of aluminum nitride and silicon nitride mixtures

    Science.gov (United States)

    Gorbatov, A. G.; Kamyshov, V. M.

    1978-01-01

    To establish the possible mechanism for conductivity in aluminum nitride a study was made of the electric conductivity of pure AlN and its mixtures with silicon nitride at different temperatures and partial pressures of nitrogen in the gas phase. The thermoelectromotive force was also measured. The experiments used polycrystalline samples of cylindrical shape 18 mm in diameter made of powders by hot pressing in graphite press molds at a temperature of 1973-2273 K and pressure 1,470,000 n/sqm. The items obtained by this method had porosity not over 5%. After pressing, the samples were machined to remove carbon from the surface, and were annealed in a stream of dry ammonia for 10 h at a temperature of 1273-1373 K. Electric conductivity was measured according to the bridge scheme on an alternating current of frequency 10 kHz. In order to guarantee close contact of the platinum electrodes with the surface of the samples, a thin layer of platinum was sprayed on them. Experiments were conducted in the temperature interval 1273-1573 K with a half hour delay at each assigned temperature with heating and cooling.

  12. Structure and properties of nitrided surface layer produced on NiTi shape memory alloy by low temperature plasma nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Czarnowska, Elżbieta [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Borowski, Tomasz [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Sowińska, Agnieszka [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Lelątko, Józef [Silesia University, Faculty of Computer Science and Materials Science, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Oleksiak, Justyna; Kamiński, Janusz; Tarnowski, Michał [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Wierzchoń, Tadeusz, E-mail: twierz@inmat.pw.edu.pl [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland)

    2015-04-15

    Highlights: • Low temperature plasma nitriding process of NiTi shape memory alloy is presented. • The possibility of treatment details of sophisticated shape. • TiN surface layer has diffusive character. • TiN surface layer increases corrosion resistance of NiTi alloy. • Produced TiN layer modify the biological properties of NiTi alloy. - Abstract: NiTi shape memory alloys are used for bone and cardiological implants. However, on account of the metallosis effect, i.e. the release of the alloy elements into surrounding tissues, they are subjected to various surface treatment processes in order to improve their corrosion resistance and biocompatibility without influencing the required shape memory properties. In this paper, the microstructure, topography and morphology of TiN surface layer on NiTi alloy, and corrosion resistance, both before and after nitriding in low-temperature plasma at 290 °C, are presented. Examinations with the use of the potentiodynamic and electrochemical impedance spectroscopy methods were carried out and show an increase of corrosion resistance in Ringer's solution after glow-discharge nitriding. This surface titanium nitride layer also improved the adhesion of platelets and the proliferation of osteoblasts, which was investigated in in vitro experiments with human cells. Experimental data revealed that nitriding NiTi shape memory alloy under low-temperature plasma improves its properties for bone implant applications.

  13. Elastic properties of indium nitrides grown on sapphire substrates determined by nano-indentation: In comparison with other nitrides

    Directory of Open Access Journals (Sweden)

    Ichiro Yonenaga

    2015-07-01

    Full Text Available The hardness of wurtzite indium nitride (α-InN films of 0.5 to 4 μm in thickness was measured by the nano-indentation method at room temperature. After investigation of crystalline quality by x-ray diffraction, the hardness and Young’s modulus were determined to be 8.8 ± 0.4 and 184 ± 5 GPa, respectively, for the In (0001- and N ( 000 1 ̄ -growth faces of InN films. The bulk and shear moduli were then derived to be 99 ± 3 and 77 ± 2 GPa, respectively. The Poisson’s ratio was evaluated to be 0.17 ± 0.03. The results were examined comprehensively in comparison with previously reported data of InN as well as those of other nitrides of aluminum nitride and gallium nitride. The underlying physical process determining the moduli and hardness was examined in terms of atomic bonding and dislocation energy of the nitrides and wurtzite zinc oxide.

  14. Carbothermic synthesis of 820 μm uranium nitride kernels: Literature review, thermodynamics, analysis, and related experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lindemer, T.B. [Harbach Engineering and Solutions, Dayton, OH 45458 (United States); Voit, S.L.; Silva, C.M.; Besmann, T.M. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6223 (United States); Hunt, R.D., E-mail: huntrd@ornl.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6223 (United States)

    2014-05-01

    The US Department of Energy is developing a new nuclear fuel that would be less susceptible to ruptures during a loss-of-coolant accident. The fuel would consist of tristructural isotropic coated particles with uranium nitride (UN) kernels with diameters near 825 μm. This effort explores factors involved in the conversion of uranium oxide–carbon microspheres into UN kernels. An analysis of previous studies with sufficient experimental details is provided. Thermodynamic calculations were made to predict pressures of carbon monoxide and other relevant gases for several reactions that can be involved in the conversion of uranium oxides and carbides into UN. Uranium oxide–carbon microspheres were heated in a microbalance with an attached mass spectrometer to determine details of calcining and carbothermic conversion in argon, nitrogen, and vacuum. A model was derived from experiments on the vacuum conversion to uranium oxide–carbide kernels. UN-containing kernels were fabricated using this vacuum conversion as part of the overall process. Carbonitride kernels of ∼89% of theoretical density were produced along with several observations concerning the different stages of the process.

  15. Electronic Biosensors Based on III-Nitride Semiconductors.

    Science.gov (United States)

    Kirste, Ronny; Rohrbaugh, Nathaniel; Bryan, Isaac; Bryan, Zachary; Collazo, Ramon; Ivanisevic, Albena

    2015-01-01

    We review recent advances of AlGaN/GaN high-electron-mobility transistor (HEMT)-based electronic biosensors. We discuss properties and fabrication of III-nitride-based biosensors. Because of their superior biocompatibility and aqueous stability, GaN-based devices are ready to be implemented as next-generation biosensors. We review surface properties, cleaning, and passivation as well as different pathways toward functionalization, and critically analyze III-nitride-based biosensors demonstrated in the literature, including those detecting DNA, bacteria, cancer antibodies, and toxins. We also discuss the high potential of these biosensors for monitoring living cardiac, fibroblast, and nerve cells. Finally, we report on current developments of covalent chemical functionalization of III-nitride devices. Our review concludes with a short outlook on future challenges and projected implementation directions of GaN-based HEMT biosensors.

  16. Active Control of Nitride Plasmonic Dispersion in the Far Infrared.

    Energy Technology Data Exchange (ETDEWEB)

    Shaner, Eric A.; Dyer, Gregory Conrad; Seng, William Francis; Bethke, Donald Thomas; Grine, Albert Dario,; Baca, Albert G.; Allerman, Andrew A.

    2014-11-01

    We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

  17. Electron microscopy of gallium nitride growth on polycrystalline diamond

    International Nuclear Information System (INIS)

    Transmission and scanning electron microscopy were used to examine the growth of gallium nitride (GaN) on polycrystalline diamond substrates grown by metalorganic vapour phase epitaxy with a low-temperature aluminium nitride (AlN) nucleation layer. Growth on unmasked substrates was in the (0001) orientation with threading dislocation densities ≈7 × 109 cm−2. An epitaxial layer overgrowth technique was used to reduce the dislocation densities further, by depositing silicon nitride stripes on the surface and etching the unmasked regions down to the diamond substrate. A re-growth was then performed on the exposed side walls of the original GaN growth, reducing the threading dislocation density in the overgrown regions by two orders of magnitude. The resulting microstructures and the mechanisms of dislocation reduction are discussed. (paper)

  18. Low-Temperature Nitriding by Means of SMAT

    Institute of Scientific and Technical Information of China (English)

    W.P. Tong; H.W. Zhang; N.R. Tao; Z.B. Wang; J. Lu; K. Lu

    2004-01-01

    The microstructure in the surface layer of iron and steel samples can be refined at the nanometer scale by means of a surface mechanical attrition treatment (SMAT) that generates repetitive severe plastic deformation to the surface layer.The subsequent nitriding kinetics of the as-treated samples with the nanostructured surface layer is greatly enhanced so that the nitriding temperatures can be reduce to 300 ~ 400 ℃ regions. This enhanced processing method demonstrates both the technological significance of nanomaterials in advancing the traditional processing techniques, and provides a new approach for selective surface reactions in solids. This article reviews the present state of the art in this field. The microstructure and properties of SMAT samples nitrided will be summarized. Further considerations of the development and applications of this new technique will also be presented.

  19. Nanoparticle plasmonics: going practical with transition metal nitrides

    Directory of Open Access Journals (Sweden)

    Urcan Guler

    2015-05-01

    Full Text Available Promising designs and experimental realizations of devices with unusual properties in the field of plasmonics have attracted a great deal of attention over the past few decades. However, the high expectations for realized technology products have not been met so far. The main complication is the absence of robust, high performance, low cost plasmonic materials that can be easily integrated into already established technologies such as microelectronics. This review provides a brief discussion on alternative plasmonic materials for localized surface plasmon applications and focuses on transition metal nitrides, in particular, titanium nitride, which has recently been shown to be a high performance refractory plasmonic material that could replace and even outperform gold in various plasmonic devices. As a material compatible with biological environments and the semiconductor industry, titanium nitride possesses superior properties compared to noble metals such as high temperature durability, chemical stability, corrosion resistance, low cost and mechanical hardness.

  20. Thermally grown thin nitride films as a gate dielectric

    CERN Document Server

    Shin, H C; Hwang, T K; Lee, K R

    1998-01-01

    High-quality very thin films ( <=6 nm) of silicon nitride were thermally grown in ammonia atmosphere with an IR (Infrared) gold image furnace. As-grown nitride film was analyzed using AES(Auger Emission Spectroscopy). Using MIS (Metal-Insulator-Semiconductor) devices, the growth rate was calculated using CV (Capacitance-Voltage) measurements and various electrical characteristics were obtained using CV, IV (Current-Voltage), trapping, time-dependent breakdown, high-field stress, constant current injection stress and dielectric breakdown techniques. These characteristics showed that very thin thermal silicon nitride films can be used as gate dielectrics for future highly scaled-down ULSI (Ultra Large Scale Integrated) devices, especially for EEPROM (Electrically Erasable and Programmable ROM)'s.

  1. Symmetric organization of self-assembled carbon nitride

    International Nuclear Information System (INIS)

    A scheme for creating 'flower-like' nanostructures of carbon nitride is described that involves the self-assembly of nanocrystals following laser ablation of a solid graphite target immersed in aqueous ammonia solution. The primary nanocrystals possess rod-like symmetry, and then self-assemble upon drying to form nanoleaf or nanopetal shaped structures. Samples were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), x-ray photoelectron microscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The analyses confirmed their composition to be consistent with that of crystalline β-phase carbon nitride. The morphologies of the carbon nitride nanostructures depended strongly on the synthesis conditions and upon the conditions under which the aqueous suspension of ablated particles were dried

  2. Pressureless sintered silicon carbide tailored with aluminium nitride sintering agent

    International Nuclear Information System (INIS)

    This study reports the influence of aluminium nitride on the pressureless sintering of cubic phase silicon carbide nanoparticles (β-SiC). Pressureless sintering was achieved at 2000 degrees C for 5 min with the additions of boron carbide together with carbon of 1 wt% and 6 wt%, respectively, and a content of aluminium nitride between 0 and 10 wt%. Sintered samples present relative densities higher than 92%. The sintered microstructure was found to be greatly modified by the introduction of aluminium nitride, which reflects the influence of nitrogen on the β-SiC to α-SiC transformation. The toughness of sintered sample was not modified by AlN incorporation and is relatively low (around 2.5 MPa m1/2). Materials exhibited transgranular fracture mode, indicating a strong bonding between SiC grains. (authors)

  3. Kinetic modelling of chlorination of nitrided ilmenite using MATLAB

    Science.gov (United States)

    Ramakrishnan, Sivakumar; Kwok, Teong Chen; Hamid, Sheikh Abdul Rezan Sheikh Abdul

    2016-07-01

    In the present study, chlorination of nitride ilmenite using 2k factorial design was investigated. The reduction experiments were carried out in a temperature range of 400°C to 500°C, chlorination duration from 1 hour to 3 hours and using different type of carbon reactant. Phases of raw materials and reduced samples were analyzed by X-ray diffraction (XRD). Ilmenite was reduced to TiOxCyNz through carbothermal and nitridation for further chlorination into titanium tetrachloride. The Design of Experiment analysis suggested that the types of carbon reactant contribute most influence to the extent of chlorination of nitride ilmenite. The extent of chlorination was highest at 500°C with 3 hours chlorination time and carbon nanotube as carbon reactant.

  4. Design, Control and in Situ Visualization of Gas Nitriding Processes

    Directory of Open Access Journals (Sweden)

    Jerzy Ratajski

    2009-12-01

    Full Text Available The article presents a complex system of design, in situ visualization and control of the commonly used surface treatment process: the gas nitriding process. In the computer design conception, analytical mathematical models and artificial intelligence methods were used. As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers. For in situ visualization of the growth of the nitrided layer, computer procedures were developed which make use of the results of the correlations of direct and differential voltage and time runs of the process result sensor (magnetic sensor, with the proper layer growth stage. Computer procedures make it possible to combine, in the duration of the process, the registered voltage and time runs with the models of the process.

  5. Grafting titanium nitride surfaces with sodium styrene sulfonate thin films.

    Science.gov (United States)

    Zorn, Gilad; Migonney, Véronique; Castner, David G

    2014-09-01

    The importance of titanium nitride lies in its high hardness and its remarkable resistance to wear and corrosion, which has led to its use as a coating for the heads of hip prostheses, dental implants and dental surgery tools. However, the usefulness of titanium nitride coatings for biomedical applications could be significantly enhanced by modifying their surface with a bioactive polymer film. The main focus of the present work was to graft a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film from titanium nitride surfaces via a two-step procedure: first modifying the surface with 3-methacryloxypropyltrimethoxysilane (MPS) and then grafting the pNaSS film from the MPS modified titanium through free radical polymerization. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used after each step to characterize success and completeness of each reaction. The surface region of the titanium nitride prior to MPS functionalization and NaSS grafting contained a mixture of titanium nitride, oxy-nitride, oxide species as well as adventitious surface contaminants. After MPS functionalization, Si was detected by XPS, and characteristic MPS fragments were detected by ToF-SIMS. After NaSS grafting, Na and S were detected by XPS and characteristic NaSS fragments were detected by ToF-SIMS. The XPS determined thicknesses of the MPS and NaSS overlayers were ∼1.5 and ∼1.7 nm, respectively. The pNaSS film density was estimated by the toluidine blue colorimetric assay to be 260 ± 70 ng/cm(2). PMID:25280842

  6. Characterization of nitrided silicon-silicon dioxide interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Polignano, M.L.; Alessandri, M.; Brazzelli, D. [and others

    2000-07-01

    A newly-developed technique for the simultaneous characterization of the oxide-silicon interface properties and of bulk impurities was used for a systematic study of the nitridation process of thin oxides. This technique is based upon surface recombination velocity measurements, and does not require the formation of a capacitor structure, so it is very suitable for the characterization of as-grown interfaces. Oxides grown both in dry and in wet environments were considered, and nitridation processes in N{sub 2}O and in NO were compared to N{sub 2} annealing processes. The effect of nitridation temperature and duration were also studied, and RTO/RTN processes were compared to conventional furnace nitridation processes. Surface recombination velocity was correlated with nitrogen concentration at the oxide-silicon interface obtained by Secondary Ion Mass Spectroscopy (SIMS) measurements. Surface recombination velocity (hence surface state density) decreases with increasing nitrogen pile-up at the oxide-silicon interface, indicating that in nitrided interfaces surface state density is limited by nitridation. NO treatments are much more effective than N{sub 2}O treatments in the formation of nitrogen-rich interface layer and, as a consequence, in surface state reduction. Surface state density was measured in fully processed wafers before and after constant current stress. After a complete device process surface states are annealed out by hydrogen passivation, however they are reactivated by the electrical stress, and surface state results after stress were compared with data of surface recombination velocity in as-processed wafers.

  7. Formation of niobium nitride by rapid thermal processing

    Science.gov (United States)

    Angelkort, C.; Lewalter, H.; Warbichler, P.; Hofer, F.; Bock, W.; Kolbesen, B. O.

    2001-09-01

    The formation of group V transition metal nitride films by means of rapid thermal processing (RTP) has been investigated. Here we focus on the nitridation of niobium films of 200-500 nm thickness in the temperature range from 500 to 1100°C under laminar flow of molecular nitrogen or ammonia. The nitride phases formed were characterized by X-ray diffraction (XRD). Secondary neutral mass spectrometry (SNMS) and transmission electron microscopy (TEM) in combination with electron energy loss spectroscopy (EELS) were carried out on samples of selected experiments to provide more detailed information about the initial stages of nitride formation and the microstructure of the films. A classical formation sequence of nitride phases was observed with increasing nitrogen content in the order: α-Nb(N)→β-Nb 2N→γ-Nb 4N 3→δ'-NbN→Nb 5N 6. Furthermore, oxide enriched regions were discovered inside the metal films. These turned out to be formed mainly in the nitride sequence between the a-αNb(N) and β-Nb 2N-phases at the Nb/SiO 2 interface due to a reaction of the Nb with the SiO 2 layer of the silicon substrates on which the films had been deposited. The SiO 2 layer acts as diffusion barrier for nitrogen but also as source for oxygen, according to SNMS and TEM/EELS studies, resulting in the formation of Nb-oxides and/or oxynitrides at the Nb/SiO 2 interface.

  8. Synthesis of reduced carbon nitride at the reduction by hydroquinone of water-soluble carbon nitride oxide (g-C3N4)O

    Science.gov (United States)

    Kharlamov, Alexey; Bondarenko, Marina; Kharlamova, Ganna; Fomenko, Veniamin

    2016-09-01

    For the first time at the reduction by hydroquinone of water-soluble carbon nitride oxide (g-C3N4)O reduced carbon nitride (or reduced multi-layer azagraphene) is obtained. It is differed from usually synthesized carbon nitride by a significantly large (on 0.09 nm) interplanar distance is. At the same time, the chemical bonds between atoms in a heteroatomic plane of reduced carbon nitride correspond to the bonds in a synthesized g-C3N4. The samples of water-soluble carbon nitride oxide were synthesized under the special reactionary conditions of a pyrolysis of melamine and urea. We believe that reduced carbon nitride consists of weakly connected carbon-nitrogen monosheets (azagraphene sheets) as well as reduced (from graphene oxide) graphene contains weakly connected graphene sheets.

  9. Preparation and characterization of morph-genetic aluminum nitride/carbon composites from filter paper

    International Nuclear Information System (INIS)

    Morph-genetic aluminum nitride/carbon composites with cablelike structure were prepared from filter paper template through the surface sol-gel process and carbothermal nitridation reaction. The resulting materials have a hierarchical structure originating from the morphology of cellulose paper. The aluminum nitride/carbon composites have the core-shell microstructure, the core is graphitic carbon, and the shell is aluminum nitride nanocoating formed by carbothermal nitridation reduction of alumina with the interfacial carbon in nitrogen atmosphere. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscope were employed to characterize the structural morphology and phase compositions of the final products

  10. The influence of nitride thickness variations on the switching speed of MNOS memory transistors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1978-01-01

    The influence of nitride thickness variations on the switching speed of MNOS memory transistors is examined. The switching time constant is calculated as a function of the nitride thickness using a model of modified Fowler-Nordheim injection. The calculated characteristics compare well with measu...... with measured characteristics and show a strong dependence on the nitride thickness.......The influence of nitride thickness variations on the switching speed of MNOS memory transistors is examined. The switching time constant is calculated as a function of the nitride thickness using a model of modified Fowler-Nordheim injection. The calculated characteristics compare well...

  11. Synthesis and Optimization of the Sintering Kinetics of Actinide Nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Drryl P. Butt; Brian Jaques

    2009-03-31

    Research conducted for this NERI project has advanced the understanding and feasibility of nitride nuclear fuel processing. In order to perform this research, necessary laboratory infrastructure was developed; including basic facilities and experimental equipment. Notable accomplishments from this project include: the synthesis of uranium, dysprosium, and cerium nitrides using a novel, low-cost mechanical method at room temperature; the synthesis of phase pure UN, DyN, and CeN using thermal methods; and the sintering of UN and (Ux, Dy1-x)N (0.7 ≤ X ≤ 1) pellets from phase pure powder that was synthesized in the Advanced Materials Laboratory at Boise State University.

  12. Structure, Mechanics and Synthesis of Nanoscale Carbon and Boron Nitride

    Science.gov (United States)

    Rinaldo, Steven G.

    This thesis is divided into two parts. In Part I, we examine the properties of thin sheets of carbon and boron nitride. We begin with an introduction to the theory of elastic sheets, where the stretching and bending modes are considered in detail. The coupling between stretching and bending modes is thought to play a crucial role in the thermodynamic stability of atomically-thin 2D sheets such as graphene. In Chapter 2, we begin by looking at the fabrication of suspended, atomically thin sheets of graphene. We then study their mechanical resonances which are read via an optical transduction technique. The frequency of the resonators was found to depend on their temperature, as was their quality factor. We conclude by offering some interpretations of the data in terms of the stretching and bending modes of graphene. In Chapter 3, we look briefly at the fabrication of thin sheets of carbon and boron nitride nanotubes. We examine the structure of the sheets using transmission and scanning electron microscopy (TEM and SEM, respectively). We then show a technique by which one can make sheets suspended over a trench with adjustable supports. Finally, DC measurements of the resistivity of the sheets in the temperature range 600 -- 1400 C are presented. In Chapter 4, we study the folding of few-layer graphene oxide, graphene and boron nitride into 3D aerogel monoliths. The properties of graphene oxide are first considered, after which the structure of graphene and boron nitride aerogels is examined using TEM and SEM. Some models for their structure are proposed. In Part II, we look at synthesis techniques for boron nitride (BN). In Chapter 5, we study the conversion of carbon structures of boron nitride via the application of carbothermal reduction of boron oxide followed by nitridation. We apply the conversion to a wide variety of morphologies, including aerogels, carbon fibers and nanotubes, and highly oriented pyrolytic graphite. In the latter chapters, we look at the

  13. Process for producing wurtzitic or cubic boron nitride

    International Nuclear Information System (INIS)

    Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described

  14. Wear monitoring of protective nitride coatings using image processing

    DEFF Research Database (Denmark)

    Rasmussen, Inge Lise; Guibert, M.; Belin, M.;

    2010-01-01

    A double-layer model system, consisting of a thin layer of tribological titanium aluminum nitride (TiAlN) on 17 top of titanium nitride (TiN), was deposited on polished 100Cr6 steel substrates. The TiAlN top-coatings 18 were exposed to abrasive wear by a reciprocating wear process in a linear tribo...... processing by color detection is a potential technique for early 25 warning or determination of residual thickness of tribological tool coatings prior to complete wear....

  15. Fabrication of sinterable silicon nitride by injection molding

    Science.gov (United States)

    Quackenbush, C. L.; French, K.; Neil, J. T.

    1982-01-01

    Transformation of structural ceramics from the laboratory to production requires development of near net shape fabrication techniques which minimize finish grinding. One potential technique for producing large quantities of complex-shaped parts at a low cost, and microstructure of sintered silicon nitride fabricated by injection molding is discussed and compared to data generated from isostatically dry-pressed material. Binder selection methodology, compounding of ceramic and binder components, injection molding techniques, and problems in binder removal are discussed. Strength, oxidation resistance, and microstructure of sintered silicon nitride fabricated by injection molding is discussed and compared to data generated from isostatically dry-pressed material.

  16. Inter-layer potential for hexagonal boron nitride

    Science.gov (United States)

    Leven, Itai; Azuri, Ido; Kronik, Leeor; Hod, Oded

    2014-03-01

    A new interlayer force-field for layered hexagonal boron nitride (h-BN) based structures is presented. The force-field contains three terms representing the interlayer attraction due to dispersive interactions, repulsion due to anisotropic overlaps of electron clouds, and monopolar electrostatic interactions. With appropriate parameterization, the potential is able to simultaneously capture well the binding and lateral sliding energies of planar h-BN based dimer systems as well as the interlayer telescoping and rotation of double walled boron-nitride nanotubes of different crystallographic orientations. The new potential thus allows for the accurate and efficient modeling and simulation of large-scale h-BN based layered structures.

  17. CONFIRM: Collaboration on Nitride Fuel Irradiation and Modelling

    International Nuclear Information System (INIS)

    Uranium free nitride fuels are investigated as a potential fuel applied to waste transmutation in accelerator driven systems. In the European 5. FP CONFIRM project, four (Pu,Zr)N helium bonded fuel pins will be fabricated at PSI and then irradiated to high burnup at Studsvik in 2003/2004. (Am,Zr)N pellets will be manufactured and characterised at ITU. In addition, nitride safety analysis and fuel modelling is performed at KTH, AEA-T, CEA and BNFL. In the present contribution, the work program of CONFIRM is reviewed. Some initial results from activities on safety analysis and fuel modelling are also presented. (author)

  18. Synthesis and Optimization of the Sintering Kinetics of Actinide Nitrides

    International Nuclear Information System (INIS)

    Research conducted for this NERI project has advanced the understanding and feasibility of nitride nuclear fuel processing. In order to perform this research, necessary laboratory infrastructure was developed; including basic facilities and experimental equipment. Notable accomplishments from this project include: the synthesis of uranium, dysprosium, and cerium nitrides using a novel, low-cost mechanical method at room temperature; the synthesis of phase pure UN, DyN, and CeN using thermal methods; and the sintering of UN and (Ux, Dy1-x)N (0.7 (le) X (le) 1) pellets from phase pure powder that was synthesized in the Advanced Materials Laboratory at Boise State University.

  19. Communication: Water on hexagonal boron nitride from diffusion Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hamdani, Yasmine S.; Ma, Ming; Michaelides, Angelos, E-mail: angelos.michaelides@ucl.ac.uk [Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH (United Kingdom); Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Alfè, Dario [Thomas Young Centre and London Centre for Nanotechnology, 17–19 Gordon Street, London WC1H 0AH (United Kingdom); Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT (United Kingdom); Lilienfeld, O. Anatole von [Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials, Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Argonne Leadership Computing Facility, Argonne National Laboratories, 9700 S. Cass Avenue Argonne, Lemont, Illinois 60439 (United States)

    2015-05-14

    Despite a recent flurry of experimental and simulation studies, an accurate estimate of the interaction strength of water molecules with hexagonal boron nitride is lacking. Here, we report quantum Monte Carlo results for the adsorption of a water monomer on a periodic hexagonal boron nitride sheet, which yield a water monomer interaction energy of −84 ± 5 meV. We use the results to evaluate the performance of several widely used density functional theory (DFT) exchange correlation functionals and find that they all deviate substantially. Differences in interaction energies between different adsorption sites are however better reproduced by DFT.

  20. Hardness and thermal stability of cubic silicon nitride

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Kragh, Flemming; Frost, D. J.;

    2001-01-01

    The hardness and thermal stability of cubic spinel silicon nitride (c-Si3N4), synthesized under high-pressure and high-temperature conditions, have been studied by microindentation measurements, and x-ray powder diffraction and scanning electron microscopy, respectively The phase at ambient...... temperature has an average hardness of 35.31 GPa, slightly larger than SiO2 stishovite, which is often referred to as the third hardest material after diamond and cubic boron nitride. The cubic phase is stable up to 1673 K in air. At 1873 K, alpha -and beta -Si3N4 phases are observed, indicating a phase...