WorldWideScience

Sample records for hot-cathode plasma chemical

  1. Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

    CERN Document Server

    Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

    2002-01-01

    The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

  2. Plasma self-oscillations in the temperature-limited current regime of a hot cathode discharge

    International Nuclear Information System (INIS)

    Arnas Capeau, C.; Bachet, G.; Doveil, F.

    1995-01-01

    Experimental observations of self-oscillations occurring in the so-called ''temperature-limited current regime'' of a hot cathode discharge are presented. Their frequency and amplitude are strongly dependent on the discharge parameters. The scaling laws of their variation and an example of a period-doubling route to chaos are reported. A two probe experiment showing that the plasma behavior is closely related to the hot cathode sheath stability is also reported. copyright 1995 American Institute of Physics

  3. Spontaneous L-H transitions under marginal hot cathode biasing in the Tohoku University Heliac

    International Nuclear Information System (INIS)

    Kitajima, S; Takahashi, H; Tanaka, Y; Utoh, H; Yokoyama, M; Inagaki, S; Suzuki, Y; Nishimura, K; Shinde, J; Ogawa, M; Iwazaki, K; Aoyama, H; Okamoto, A; Shinto, K; Sasao, M

    2006-01-01

    A series of hot cathode biasing experiments with marginal conditions for improved mode transition were carried out in the Tohoku University Heliac (TU-Heliac). Spontaneous transitions were observed accompanied by a delay of a few milliseconds. Transition conditions were explored over a wide operation range. The transition points can be identified clearly and easily in the operation range, because the plasma parameters changed slowly until the spontaneous transition. Although operation conditions were spread over a wide range, poloidal Mach numbers for transitions were concentrated in the range of -M p = 1-2 and normalized driving forces for poloidal rotation agreed well with the local maximum value of ion viscosity predicted by neoclassical theory. The local maximum of ion viscosity against the poloidal Mach number was found to play a key role in the L-H transition. Marginal hot cathode biasing is suitable to determine the threshold conditions for the L-H transition

  4. Study on a negative hydrogen ion source with hot cathode arc discharge.

    Science.gov (United States)

    Lin, S H; Fang, X; Zhang, H J; Qian, C; Ma, B H; Wang, H; Li, X X; Zhang, X Z; Sun, L T; Zhang, Z M; Yuan, P; Zhao, H W

    2014-02-01

    A negative hydrogen (H(-)) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H(-) beam with ɛ N, RMS = 0.08 π mm mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of I(e(-))/I(H(-)) were experimentally studied. The discussion on the result, and opinions to improve the source were given.

  5. Effect of energetic electrons on dust charging in hot cathode filament discharge

    Science.gov (United States)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2011-03-01

    The effect of energetic electrons on dust charging for different types of dust is studied in hydrogen plasma. The hydrogen plasma is produced by hot cathode filament discharge method in a dusty plasma device. A full line cusped magnetic field cage is used to confine the plasma elements. To study the plasma parameters for various discharge conditions, a cylindrical Langmuir probe having 0.15 mm diameter and 10.0 mm length is used. An electronically controlled dust dropper is used to drop the dust particles into the plasma. For different discharge conditions, the dust current is measured using a Faraday cup connected to an electrometer. The effect of secondary emission as well as discharge voltage on charging of dust grains in hydrogen plasma is studied with different dust.

  6. Effect of energetic electrons on dust charging in hot cathode filament discharge

    International Nuclear Information System (INIS)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2011-01-01

    The effect of energetic electrons on dust charging for different types of dust is studied in hydrogen plasma. The hydrogen plasma is produced by hot cathode filament discharge method in a dusty plasma device. A full line cusped magnetic field cage is used to confine the plasma elements. To study the plasma parameters for various discharge conditions, a cylindrical Langmuir probe having 0.15 mm diameter and 10.0 mm length is used. An electronically controlled dust dropper is used to drop the dust particles into the plasma. For different discharge conditions, the dust current is measured using a Faraday cup connected to an electrometer. The effect of secondary emission as well as discharge voltage on charging of dust grains in hydrogen plasma is studied with different dust.

  7. Sensitivity of hot-cathode ionization vacuum gages in several gases

    Science.gov (United States)

    Holanda, R.

    1972-01-01

    Four hot-cathode ionization vacuum gages were calibrated in 12 gases. The relative sensitivities of these gages were compared to several gas properties. Ionization cross section was the physical property which correlated best with gage sensitivity. The effects of gage accelerating voltage and ionization-cross-section energy level were analyzed. Recommendations for predicting gage sensitivity according to gage type were made.

  8. Hot Cathode Biasing Experiment in Compact Helical System

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, H.; Utoh, H.; Kitajima, S.; Isobe, M.; Suzuki, C.; Takeuchi, M.; Ikeda, R.; Tanaka, Y.; Yokoyama, M.; Toi, K.; Okamura, S.; Sasao, M.

    2005-07-01

    One of the H mode characteristics is a sudden formation of a radial electric field at LH transition. To date, H mode was widely observed in various tokamaks [1-3] and stellarator devices [4, 5], and the importance of the radial electric field has been shown in both experiments and in theory. However, it is difficult to investigate the behaviour of a radial electric field in detail at LH transition induced by NBI heating because the radial electric field is self-organised and changes suddenly. Electrode bias experiments are methods for active control of the radial electric field. The electrode bias experiment has the advantage of the ability to control the radial electric field externally by controlling the electrode voltage and/or the electrode current and to estimate the driving force from the electrode current. The neoclassical theory indicates the criterion of LH transition from the viewpoint of the ion viscosity. In this theory, the ion viscosity has local maxima against the rotation velocity [6-8]. When the driving force in the poloidal direction exceeds a critical value, the poloidal rotation velocity increases rapidly and the plasma undergoes a transition to the H mode. This means that the LH transition mechanism is a bifurcation phenomenon due to the existence of local maxima in the ion viscosity. Here, we carried out the electrode biasing experiment in TU-Heliac and CHS to investigate the effect of ripple structure on ion viscosity and to clarify the role of ion viscosity in triggering the transition from the degraded state to enhanced confinement. (Author)

  9. Study of ion viscosity by spontaneous L-H transitions under marginal hot cathode biasing in the Tohoku University Heliac

    International Nuclear Information System (INIS)

    Kitajima, S.; Takahashi, H.; Tanaka, Y.; Utoh, H.; Takenaga, M.; Yokoyama, M.; Inagaki, S.; Suzuki, Y.; Nishimura, K.; Ogawa, H.; Takayama, M.; Shinde, J.; Ogawa, M.; Aoyama, H.; Iwazaki, K.; Okamoto, A.; Shinto, K.; Sasao, M.

    2008-01-01

    Using the spontaneous transition condition under marginal hot cathode biasing, the ion viscosity at the L-H transition was estimated in various magnetic configurations in the Tohoku University Heliac. The critical viscosity, which is the viscosity at the transition point, was experimentally estimated from the J x B driving force. The critical viscosities in different magnetic configurations were in agreement with the neoclassical predictions within a factor of 2 and were compared with the viscosities obtained in the externally forced biasing experiments. Although the transition points were spread over a wide range, poloidal Mach numbers at the transition point were concentrated near the viscosity maxima predicted by the theory

  10. Plasma-chemical processes and systems

    International Nuclear Information System (INIS)

    Castro B, J.

    1987-01-01

    The direct applications of plasma technology on chemistry and metallurgy are presented. The physical fundaments of chemically active non-equilibrium plasma, the reaction kinetics, and the physical chemical transformations occuring in the electrical discharges, which are applied in the industry, are analysed. Some plasma chemical systems and processes related to the energy of hydrogen, with the chemical technology and with the metallurgy are described. Emphasis is given to the optimization of the energy effectiveness of these processes to obtain reducers and artificial energetic carriers. (M.C.K.) [pt

  11. Fundamental aspects of plasma chemical physics Thermodynamics

    CERN Document Server

    Capitelli, Mario; D'Angola, Antonio

    2012-01-01

    Fundamental Aspects of Plasma Chemical Physics - Thermodynamics develops basic and advanced concepts of plasma thermodynamics from both classical and statistical points of view. After a refreshment of classical thermodynamics applied to the dissociation and ionization regimes, the book invites the reader to discover the role of electronic excitation in affecting the properties of plasmas, a topic often overlooked by the thermal plasma community. Particular attention is devoted to the problem of the divergence of the partition function of atomic species and the state-to-state approach for calculating the partition function of diatomic and polyatomic molecules. The limit of ideal gas approximation is also discussed, by introducing Debye-Huckel and virial corrections. Throughout the book, worked examples are given in order to clarify concepts and mathematical approaches. This book is a first of a series of three books to be published by the authors on fundamental aspects of plasma chemical physics.  The next bo...

  12. Thermal plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Heberlein, J.; Pfender, E.

    1993-01-01

    Thermal plasmas, with temperatures up to and even exceeding 10 4 K, are capable of producing high density vapor phase precursors for the deposition of relatively thick films. Although this technology is still in its infancy, it will fill the void between the relatively slow deposition processes such as physical vapor deposition and the high rate thermal spray deposition processes. In this chapter, the present state-of-the-art of this field is reviewed with emphasis on the various types of reactors proposed for this emerging technology. Only applications which attracted particular attention, namely diamond and high T c superconducting film deposition, are discussed in greater detail. (orig.)

  13. Fundamental aspects of plasma chemical physics transport

    CERN Document Server

    Capitelli, Mario; Laricchiuta, Annarita

    2013-01-01

    Fundamental Aspects of Plasma Chemical Physics: Tranpsort develops basic and advanced concepts of plasma transport to the modern treatment of the Chapman-Enskog method for the solution of the Boltzmann transport equation. The book invites the reader to consider actual problems of the transport of thermal plasmas with particular attention to the derivation of diffusion- and viscosity-type transport cross sections, stressing the role of resonant charge-exchange processes in affecting the diffusion-type collision calculation of viscosity-type collision integrals. A wide range of topics is then discussed including (1) the effect of non-equilibrium vibrational distributions on the transport of vibrational energy, (2) the role of electronically excited states in the transport properties of thermal plasmas, (3) the dependence of transport properties on the multitude of Saha equations for multi-temperature plasmas, and (4) the effect of the magnetic field on transport properties. Throughout the book, worked examples ...

  14. Chemical analysis of refractories by plasma spectrometry

    International Nuclear Information System (INIS)

    Coutinho, C.A.

    1990-01-01

    X-ray spectrometry has been, since the last two or three decades, the traditional procedure for the chemical analysis of refractories, due to its high degree of accuracy and speed to produce analytical results. An interesting alternative to X-ray fluorescence is provided by the Inductively Coupled Plasma Spectrometry technique, for those laboratories where wet chemistry facilities are already available or process control is not required at high speed, or investiment costs have to be low. This paper presents results obtained by plasma spectroscopy for the analysis of silico - aluminous refractories, showing calibration curves, precion and detection limits. Considerations and comparisons with X-ray fluorescence are also made. (author) [pt

  15. Fundamental aspects of plasma chemical physics kinetics

    CERN Document Server

    Capitelli, Mario; Colonna, Gianpiero; Esposito, Fabrizio; Gorse, Claudine; Hassouni, Khaled; Laricchiuta, Annarita; Longo, Savino

    2016-01-01

    Describing non-equilibrium "cold" plasmas through a chemical physics approach, this book uses the state-to-state plasma kinetics, which considers each internal state as a new species with its own cross sections. Extended atomic and molecular master equations are coupled with Boltzmann and Monte Carlo methods to solve the electron energy distribution function. Selected examples in different applied fields, such as microelectronics, fusion, and aerospace, are presented and discussed including the self-consistent kinetics in RF parallel plate reactors, the optimization of negative ion sources and the expansion of high enthalpy flows through nozzles of different geometries. The book will cover the main aspects of the state-to-state kinetic approach for the description of nonequilibrium cold plasmas, illustrating the more recent achievements in the development of kinetic models including the self-consistent coupling of master equations and Boltzmann equation for electron dynamics. To give a complete portrayal, the...

  16. Strangeness Production in a Chemically Equilibrating Quark-Gluon Plasma

    Institute of Scientific and Technical Information of China (English)

    HE Ze-Jun; LONG Jia-Li; MA Yu-Gang; MA Guo-Liang

    2004-01-01

    @@ We study the strangeness of a chemically equilibrating quark-gluon plasma at finite baryon density based on the and will accelerate with the change of the initial system from a chemically non-equilibrated to an equilibrated system. We also find that the calculated strangeness is very different from the one in the thermodynamic equilibrium system. This study may be helpful to understand the formation of quark-gluon plasma via a chemically non-equilibrated evolution framework.

  17. Wave propagation in a quasi-chemical equilibrium plasma

    Science.gov (United States)

    Fang, T.-M.; Baum, H. R.

    1975-01-01

    Wave propagation in a quasi-chemical equilibrium plasma is studied. The plasma is infinite and without external fields. The chemical reactions are assumed to result from the ionization and recombination processes. When the gas is near equilibrium, the dominant role describing the evolution of a reacting plasma is played by the global conservation equations. These equations are first derived and then used to study the small amplitude wave motion for a near-equilibrium situation. Nontrivial damping effects have been obtained by including the conduction current terms.

  18. Microwave plasma emerging technologies for chemical processes

    NARCIS (Netherlands)

    de la Fuente, Javier F.; Kiss, Anton A.; Radoiu, Marilena T.; Stefanidis, Georgios D.

    2017-01-01

    Microwave plasma (MWP) technology is currently being used in application fields such as semiconductor and material processing, diamond film deposition and waste remediation. Specific advantages of the technology include the enablement of a high energy density source and a highly reactive medium,

  19. Influence of Chemical Precleaning on the Plasma Treatment Efficiency of Aluminum by RF Plasma Pencil

    Czech Academy of Sciences Publication Activity Database

    Prysiazhnyi, V.; Slavíček, P.; Mikmeková, Eliška; Klíma, M.

    2016-01-01

    Roč. 18, č. 4 (2016), s. 430-437 ISSN 1009-0630 Institutional support: RVO:68081731 Keywords : atmospheric pressure plasma * plasma jet * aluminium * surface treatment * surface processing * chemical precleaning Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.830, year: 2016

  20. Characteristics of nanosized zirconia prepared by plasma and chemical technique

    International Nuclear Information System (INIS)

    Kuznetsova, L.; Grabis, J.; Heidemane, G.

    2003-01-01

    The studied preparation method of zirconia using the plasma technique, azeotropic distillation and glycine routes ensure obtaining of nano sized powders with close average particle size but different crystallite size and phase composition. The sinterability of nano sized zirconia particles prepared by plasma technique or wet-chemical methods is similar and depends on the green density of pressed powders, improvement of with can be achieved by using of granulated precursors. (authors)

  1. Chemical analysis of plasma-assisted antimicrobial treatment on cotton

    International Nuclear Information System (INIS)

    Kan, C W; Lam, Y L; Yuen, C W M; Luximon, A; Lau, K W; Chen, K S

    2013-01-01

    This paper explores the use of plasma treatment as a pretreatment process to assist the application of antimicrobial process on cotton fabric with good functional effect. In this paper, antimicrobial finishing agent, Microfresh Liquid Formulation 9200-200 (MF), and a binder (polyurethane dispersion, Microban Liquid Formulation R10800-0, MB) will be used for treating the cotton fabric for improving the antimicrobial property and pre-treatment of cotton fabric by plasma under atmospheric pressure will be employed to improve loading of chemical agents. The chemical analysis of the treated cotton fabric will be conducted by Fourier transform Infrared Spectroscopy.

  2. On improved understanding of plasma-chemical processes in complex low-temperature plasmas

    Science.gov (United States)

    Röpcke, Jürgen; Loffhagen, Detlef; von Wahl, Eric; Nave, Andy S. C.; Hamann, Stephan; van Helden, Jean-Piere H.; Lang, Norbert; Kersten, Holger

    2018-05-01

    Over the last years, chemical sensing using optical emission spectroscopy (OES) in the visible spectral range has been combined with methods of mid infrared laser absorption spectroscopy (MIR-LAS) in the molecular fingerprint region from 3 to 20 μm, which contains strong rotational-vibrational absorption bands of a large variety of gaseous species. This optical approach established powerful in situ diagnostic tools to study plasma-chemical processes of complex low-temperature plasmas. The methods of MIR-LAS enable to detect stable and transient molecular species in ground and excited states and to measure the concentrations and temperatures of reactive species in plasmas. Since kinetic processes are inherent to discharges ignited in molecular gases, high time resolution on sub-second timescales is frequently desired for fundamental studies as well as for process monitoring in applied research and industry. In addition to high sensitivity and good temporal resolution, the capacity for broad spectral coverage enabling multicomponent detection is further expanding the use of OES and MIR-LAS techniques. Based on selected examples, this paper reports on recent achievements in the understanding of complex low-temperature plasmas. Recently, a link with chemical modeling of the plasma has been provided, which is the ultimate objective for a better understanding of the chemical and reaction kinetic processes occurring in the plasma. Contribution to the Topical Issue "Fundamentals of Complex Plasmas", edited by Jürgen Meichsner, Michael Bonitz, Holger Fehske, Alexander Piel.

  3. Influence of Chemical Precleaning on the Plasma Treatment Efficiency of Aluminum by RF Plasma Pencil

    International Nuclear Information System (INIS)

    Prysiazhnyi, Vadym; Slavicek, Pavel; Klima, Milos; Mikmekova, Eliska

    2016-01-01

    This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces. The results of our study showed that the state of the topmost surface layer (i.e. the surface morphology and chemical groups) of plasma modified aluminum significantly depends on the chemical precleaning. Commonly used chemicals (isopropanol, trichlorethane, solution of NaOH in deionized water) were used as precleaning agents. The plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University, which operates in Ar, Ar/O 2 gas mixtures. The effectiveness of the plasma treatment was estimated by the wettability measurements, showing high wettability improvement already after 0.3 s treatment. The effects of surface cleaning (hydrocarbon removal), surface oxidation and activation (generation of OH groups) were estimated using infrared spectroscopy. The changes in the surface morphology were measured using scanning electron microscopy. Optical emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure. (paper)

  4. Influence of Chemical Precleaning on the Plasma Treatment Efficiency of Aluminum by RF Plasma Pencil

    Science.gov (United States)

    Vadym, Prysiazhnyi; Pavel, Slavicek; Eliska, Mikmekova; Milos, Klima

    2016-04-01

    This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces. The results of our study showed that the state of the topmost surface layer (i.e. the surface morphology and chemical groups) of plasma modified aluminum significantly depends on the chemical precleaning. Commonly used chemicals (isopropanol, trichlorethane, solution of NaOH in deionized water) were used as precleaning agents. The plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University, which operates in Ar, Ar/O2 gas mixtures. The effectiveness of the plasma treatment was estimated by the wettability measurements, showing high wettability improvement already after 0.3 s treatment. The effects of surface cleaning (hydrocarbon removal), surface oxidation and activation (generation of OH groups) were estimated using infrared spectroscopy. The changes in the surface morphology were measured using scanning electron microscopy. Optical emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure.

  5. Plasma effects in aligned carbon nanoflake growth by plasma-enhanced hot filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, B.B. [College of Chemistry and Chemical Engineering, Chongqing University of Technology, 69 Hongguang Rd, Lijiatuo, Banan District, Chongqing 400054 (China); Zheng, K. [Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Cheng, Q.J., E-mail: qijin.cheng@xmu.edu.cn [School of Energy Research, Xiamen University, Xiamen 361005 (China); Ostrikov, K. [Plasma Nanoscience Center Australia (PNCA), Manufacturing Flagship, Commonwealth Scientific and Industrial Research Organization, PO Box 218, Lindfield 2070, NSW (Australia); Institute for Future Environments and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, QLD (Australia); Plasma Nanoscience, School of Physics, The University of Sydney, Sydney 2006, NSW (Australia)

    2015-01-15

    Highlights: • Plasma-specific effects in the growth of carbon nanoflakes (CNFs) are studied. • Electic field in the plasma sheath promotes separation of CNFs from the substrate. • The orentention of GNFs is related to the combined electic force and growth effects. • The high growth grates of aligned GNFs are plasma-related. - Abstract: Carbon nanofilms are directly grown on silicon substrates by plasma-enhanced hot filament chemical vapor deposition in methane environment. It is shown that the nanofilms are composed of aligned carbon nanoflakes by extensive investigation of experimental results of field emission scanning electron microscopy, micro-Raman spectroscopy and transmission electron microscopy. In comparison with the graphene-like films grown without plasmas, the carbon nanoflakes grow in an alignment mode and the growth rate of the films is increased. The effects of the plasma on the growth of the carbon nanofilms are studied. The plasma plays three main effects of (1) promoting the separation of the carbon nanoflakes from the silicon substrate, (2) accelerating the motion of hydrocarbon radicals, and (3) enhancing the deposition of hydrocarbon ions onto the substrate surface. Due to these plasma-specific effects, the carbon nanofilms can be formed from the aligned carbon nanoflakes with a high rate. These results advance our knowledge on the synthesis, properties and applications of graphene-based materials.

  6. Applying chemical engineering concepts to non-thermal plasma reactors

    Science.gov (United States)

    Pedro AFFONSO, NOBREGA; Alain, GAUNAND; Vandad, ROHANI; François, CAUNEAU; Laurent, FULCHERI

    2018-06-01

    Process scale-up remains a considerable challenge for environmental applications of non-thermal plasmas. Undersanding the impact of reactor hydrodynamics in the performance of the process is a key step to overcome this challenge. In this work, we apply chemical engineering concepts to analyse the impact that different non-thermal plasma reactor configurations and regimes, such as laminar or plug flow, may have on the reactor performance. We do this in the particular context of the removal of pollutants by non-thermal plasmas, for which a simplified model is available. We generalise this model to different reactor configurations and, under certain hypotheses, we show that a reactor in the laminar regime may have a behaviour significantly different from one in the plug flow regime, often assumed in the non-thermal plasma literature. On the other hand, we show that a packed-bed reactor behaves very similarly to one in the plug flow regime. Beyond those results, the reader will find in this work a quick introduction to chemical reaction engineering concepts.

  7. Atmospheric Pressure Plasma Induced Sterilization and Chemical Neutralization

    Science.gov (United States)

    Garate, Eusebio; Evans, Kirk; Gornostaeva, Olga; Alexeff, Igor; Lock Kang, Weng; Wood, Thomas K.

    1998-11-01

    We are studying chemical neutralization and surface decontamination using atmospheric pressure plasma discharges. The plasma is produced by corona discharge from an array of pins and a ground plane. The array is constructed so that various gases, like argon or helium, can be flowed past the pins where the discharge is initiated. The pin array can be biased using either DC, AC or pulsed discharges. Results indicate that the atmospheric plasma is effective in sterilizing surfaces with biological contaminants like E-coli and bacillus subtilus cells. Exposure times of less than four minutes in an air plasma result in a decrease in live colony counts by six orders of magnitude. Greater exposure times result in a decrease of live colony counts of up to ten orders of magnitude. The atmospheric pressure discharge is also effective in decomposing organic phosphate compounds that are simulants for chemical warfare agents. Details of the decomposition chemistry, by-product formation, and electrical energy consumption of the system will be discussed.

  8. Typical parameters of the plasma chemical similarity in non-isothermal reactive plasmas

    International Nuclear Information System (INIS)

    Gundermann, S.; Jacobs, H.; Miethke, F.; Rutsher, A.; Wagner, H.E.

    1996-01-01

    The substance of physical similarity principles is contained in parameters which govern the comparison of different realizations of a model device. Because similarity parameters for non-isothermal plasma chemical reactors are unknown to a great extent, an analysis of relevant equations is given together with some experimental results. Modelling of the reactor and experimental results for the ozone synthesis are presented

  9. Review: Plasma-enhanced chemical vapor deposition of nanocrystalline diamond

    Directory of Open Access Journals (Sweden)

    Katsuyuki Okada

    2007-01-01

    Full Text Available Nanocrystalline diamond films have attracted considerable attention because they have a low coefficient of friction and a low electron emission threshold voltage. In this paper, the author reviews the plasma-enhanced chemical vapor deposition (PE-CVD of nanocrystalline diamond and mainly focuses on the growth of nanocrystalline diamond by low-pressure PE-CVD. Nanocrystalline diamond particles of 200–700 nm diameter have been prepared in a 13.56 MHz low-pressure inductively coupled CH4/CO/H2 plasma. The bonding state of carbon atoms was investigated by ultraviolet-excited Raman spectroscopy. Electron energy loss spectroscopy identified sp2-bonded carbons around the 20–50 nm subgrains of nanocrystalline diamond particles. Plasma diagnostics using a Langmuir probe and the comparison with plasma simulation are also reviewed. The electron energy distribution functions are discussed by considering different inelastic interaction channels between electrons and heavy particles in a molecular CH4/H2 plasma.

  10. Chemical and physical reactions under thermal plasmas conditions

    International Nuclear Information System (INIS)

    Fauchais, P.; Vardelle, A.; Vardelle, M.; Coudert, J.F.

    1987-01-01

    Basic understanding of the involved phenomena lags far behind industrial development that requires now a better knowledge of the phenomena to achieve a better control of the process allowing to improve the quality of the products. Thus the authors try to precise what is their actual knowledge in the fields of: plasma generators design; plasma flow models with the following key points: laminar or turbulent flow, heat transfer to walls, 2D or 3D models, non equilibrium effects, mixing problems when chemical reactions are to be taken into account with very fast kinetics, electrode regions, data for transport properties and kinetic rates; nucleation problems; plasma flow characteristics measurements: temperature or temperatures and population of excited states (automatized emission spectroscopy, LIF, CARS) as well as flow velocity (LDA with small particles, Doppler effects...); plasma and particles momentum and heat transfer either with models taking into account particles size and injection velocity distributions, heat propagation, vaporization, Kundsen effect, turbulences ... or with measurements: particles velocity and flux distributions (Laser Anemometry) as well as surface temperature distributions (two colour pyrometry in flight statistical or not)

  11. Plasma Enhanced Chemical Vapour Deposition of Horizontally Aligned Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Matthew T. Cole

    2013-05-01

    Full Text Available A plasma-enhanced chemical vapour deposition reactor has been developed to synthesis horizontally aligned carbon nanotubes. The width of the aligning sheath was modelled based on a collisionless, quasi-neutral, Child’s law ion sheath where these estimates were empirically validated by direct Langmuir probe measurements, thereby confirming the proposed reactors ability to extend the existing sheath fields by up to 7 mm. A 7 mbar growth atmosphere combined with a 25 W plasma permitted the concurrent growth and alignment of carbon nanotubes with electric fields of the order of 0.04 V μm−1 with linear packing densities of up to ~5 × 104 cm−1. These results open up the potential for multi-directional in situ alignment of carbon nanotubes providing one viable route to the fabrication of many novel optoelectronic devices.

  12. Substrate Effect on Plasma Clean Efficiency in Plasma Enhanced Chemical Vapor Deposition System

    Directory of Open Access Journals (Sweden)

    Shiu-Ko JangJian

    2007-01-01

    Full Text Available The plasma clean in a plasma-enhanced chemical vapor deposition (PECVD system plays an important role to ensure the same chamber condition after numerous film depositions. The periodic and applicable plasma clean in deposition chamber also increases wafer yield due to less defect produced during the deposition process. In this study, the plasma clean rate (PCR of silicon oxide is investigated after the silicon nitride deposited on Cu and silicon oxide substrates by remote plasma system (RPS, respectively. The experimental results show that the PCR drastically decreases with Cu substrate compared to that with silicon oxide substrate after numerous silicon nitride depositions. To understand the substrate effect on PCR, the surface element analysis and bonding configuration are executed by X-ray photoelectron spectroscopy (XPS. The high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS is used to analyze microelement of metal ions on the surface of shower head in the PECVD chamber. According to Cu substrate, the results show that micro Cu ion and the CuOx bonding can be detected on the surface of shower head. The Cu ion contamination might grab the fluorine radicals produced by NF3 ddissociation in the RPS and that induces the drastic decrease on PCR.

  13. Nitrogen-doped graphene by microwave plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kumar, A.; Voevodin, A.A.; Paul, R.; Altfeder, I.; Zemlyanov, D.; Zakharov, D.N.; Fisher, T.S.

    2013-01-01

    Rapid synthesis of nitrogen-doped, few-layer graphene films on Cu foil is achieved by microwave plasma chemical vapor deposition. The films are doped during synthesis by introduction of nitrogen gas in the reactor. Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning tunneling microscopy reveal crystal structure and chemical characteristics. Nitrogen concentrations up to 2 at.% are observed, and the limit is linked to the rigidity of graphene films on copper surfaces that impedes further nitrogen substitutions of carbon atoms. The entire growth process requires only a few minutes without supplemental substrate heating and offers a promising path toward large-scale synthesis of nitrogen-doped graphene films. - Highlights: ► Rapid synthesis of nitrogen doped few layer graphene on Cu foil. ► Defect density increment on 2% nitrogen doping. ► Nitrogen doped graphene is a good protection to the copper metallic surface

  14. Nitrogen-doped graphene by microwave plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A., E-mail: kumar50@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Voevodin, A.A. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Paul, R. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Altfeder, I. [Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Zemlyanov, D.; Zakharov, D.N. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Fisher, T.S., E-mail: tsfisher@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States)

    2013-01-01

    Rapid synthesis of nitrogen-doped, few-layer graphene films on Cu foil is achieved by microwave plasma chemical vapor deposition. The films are doped during synthesis by introduction of nitrogen gas in the reactor. Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning tunneling microscopy reveal crystal structure and chemical characteristics. Nitrogen concentrations up to 2 at.% are observed, and the limit is linked to the rigidity of graphene films on copper surfaces that impedes further nitrogen substitutions of carbon atoms. The entire growth process requires only a few minutes without supplemental substrate heating and offers a promising path toward large-scale synthesis of nitrogen-doped graphene films. - Highlights: ► Rapid synthesis of nitrogen doped few layer graphene on Cu foil. ► Defect density increment on 2% nitrogen doping. ► Nitrogen doped graphene is a good protection to the copper metallic surface.

  15. Strangeness chemical equilibration in a quark-gluon plasma

    International Nuclear Information System (INIS)

    Letessier, Jean; Rafelski, Johann

    2007-01-01

    We study, in the dynamically evolving quark-gluon plasma (QGP) fireball formed in relativistic heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC), the growth of strangeness yield toward and beyond the chemical equilibrium. We account for the contribution of the direct strangeness production and evaluate the thermal-QCD strangeness production mechanisms. The specific yield of strangeness per entropy, s/S, is the primary target variable. We explore the effect of collision impact parameter, i.e., fireball size, on kinetic strangeness chemical equilibration in QGP. Insights gained in studying the RHIC data with regard to the dynamics of the fireball are applied to the study of strangeness production at the LHC. We use these results and consider the strange hadron relative particle yields at RHIC and LHC in a systematic fashion. We consider both the dependence on s/S and the direct dependence on the participant number

  16. Tungsten Deposition on Graphite using Plasma Enhanced Chemical Vapour Deposition

    International Nuclear Information System (INIS)

    Sharma, Uttam; Chauhan, Sachin S; Sharma, Jayshree; Sanyasi, A K; Ghosh, J; Choudhary, K K; Ghosh, S K

    2016-01-01

    The tokamak concept is the frontrunner for achieving controlled thermonuclear reaction on earth, an environment friendly way to solve future energy crisis. Although much progress has been made in controlling the heated fusion plasmas (temperature ∼ 150 million degrees) in tokamaks, technological issues related to plasma wall interaction topic still need focused attention. In future, reactor grade tokamak operational scenarios, the reactor wall and target plates are expected to experience a heat load of 10 MW/m 2 and even more during the unfortunate events of ELM's and disruptions. Tungsten remains a suitable choice for the wall and target plates. It can withstand high temperatures, its ductile to brittle temperature is fairly low and it has low sputtering yield and low fuel retention capabilities. However, it is difficult to machine tungsten and hence usages of tungsten coated surfaces are mostly desirable. To produce tungsten coated graphite tiles for the above-mentioned purpose, a coating reactor has been designed, developed and made operational at the SVITS, Indore. Tungsten coating on graphite has been attempted and successfully carried out by using radio frequency induced plasma enhanced chemical vapour deposition (rf -PECVD) for the first time in India. Tungsten hexa-fluoride has been used as a pre-cursor gas. Energy Dispersive X-ray spectroscopy (EDS) clearly showed the presence of tungsten coating on the graphite samples. This paper presents the details of successful operation and achievement of tungsten coating in the reactor at SVITS. (paper)

  17. Quasi-equilibria and plasma chemical similarity in non-isothermal reactive plasmas

    International Nuclear Information System (INIS)

    Miethke, F.; Rutscher, A.; Wagner, H.E.

    2000-01-01

    With regard to the output of stable products the mode of operation of non-isothermal plasma chemical reactors shows physical and chemical well defined states, which represent limiting cases and may be interpreted as quasi-equilibrium states. The occurrence and the characteristics of these states, meanwhile more than once observed and described, are demonstrated by an instructive model reaction. Within the frame of the so-called Macroscopic Kinetics a central parameter is dominating the reactor operation. This result may be generalized and is linked up to the application of similarity principles for the reactor operation. After the general formulation of such principles, starting from the balance equations of particles and energy, a dimensionless similarity parameter is formulated, characterizing the composition of the effluent gas of the reactor. The applicability of this parameter is demonstrated by experimental examples. (Authors)

  18. Chemical characterization of materials by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Deb, S.B.; Nagar, B.K.; Saxena, M.K.; Ramakumar, K.L.

    2009-11-01

    An Inductively Coupled Plasma Mass Spectrometer was procured for trace elemental determination in diverse samples. Since its installation a number of analytical measurements have been carried out on different sample matrices. These include chemical quality control measurements of nuclear fuel and other materials such as uranium metal. Uranium peroxide, ADU, ThO 2 , UO 2 ; isotopic composition of B, Li; chemical characterization of simulated ThO 2 + 2%UO 2 fuel; sodium zirconium phosphate and trace metallic elements in zirconium; Antarctica rock samples and wet phosphoric acid. Necessary separation methodologies required for effective removal of matrix were indigenously developed. In addition, a rigorous analytical protocol, which includes various calibration methodologies such as mass calibration, response calibration, detector cross calibration and linearity check over the entire dynamic range of 109 required for quantitative determination of elements at trace and ultra trace level,, has been standardized. This report summarizes efforts of RACD that have been put in this direction for the application of ICP-MS for analytical measurements. (author)

  19. Chemical Evolution of Strongly Interacting Quark-Gluon Plasma

    International Nuclear Information System (INIS)

    Pan, Ying-Hua; Zhang, Wei-Ning

    2014-01-01

    At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations

  20. Reduced chemical warfare agent sorption in polyurethane-painted surfaces via plasma-enhanced chemical vapor deposition of perfluoroalkanes.

    Science.gov (United States)

    Gordon, Wesley O; Peterson, Gregory W; Durke, Erin M

    2015-04-01

    Perfluoralkalation via plasma chemical vapor deposition has been used to improve hydrophobicity of surfaces. We have investigated this technique to improve the resistance of commercial polyurethane coatings to chemicals, such as chemical warfare agents. The reported results indicate the surface treatment minimizes the spread of agent droplets and the sorption of agent into the coating. The improvement in resistance is likely due to reduction of the coating's surface free energy via fluorine incorporation, but may also have contributing effects from surface morphology changes. The data indicates that plasma-based surface modifications may have utility in improving chemical resistance of commercial coatings.

  1. The material balance of process of plasma-chemical conversion of polymer wastes into synthesis gas

    International Nuclear Information System (INIS)

    Tazmeev, A Kh; Tazmeeva, R N

    2017-01-01

    The process of conversion of polymer wastes in the flow of water-steam plasma which are created by the liquid electrodes plasma generators was experimentally studied. The material balance was calculated. The regularities of the participating of hydrogen and oxygen which contained in the water-steam plasma, in formation of chemical compounds in the final products were revealed. (paper)

  2. The material balance of process of plasma-chemical conversion of polymer wastes into synthesis gas

    Science.gov (United States)

    Tazmeev, A. Kh; Tazmeeva, R. N.

    2017-01-01

    The process of conversion of polymer wastes in the flow of water-steam plasma which are created by the liquid electrodes plasma generators was experimentally studied. The material balance was calculated. The regularities of the participating of hydrogen and oxygen which contained in the water-steam plasma, in formation of chemical compounds in the final products were revealed.

  3. Surface chemical changes of atmospheric pressure plasma treated rabbit fibres important for felting process

    Energy Technology Data Exchange (ETDEWEB)

    Štěpánová, Vlasta, E-mail: vstepanova@mail.muni.cz [Department of Physical Electronics, Faculty of Science Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Slavíček, Pavel; Stupavská, Monika; Jurmanová, Jana [Department of Physical Electronics, Faculty of Science Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Černák, Mirko [Department of Physical Electronics, Faculty of Science Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2, 842 48 Bratislava (Slovakia)

    2015-11-15

    Graphical abstract: - Highlights: • Rabbit fibres plasma treatment is an effective method for fibres modification. • Atmospheric pressure plasma treatment is able to affect fibres properties. • Surface changes on fibres after plasma treatment were analysed via SEM, ATR-FTIR, XPS. • Significant increase of fibres wettability after plasma treatment was observed. • Plasma treatment at atmospheric pressure can replace the chemical treatment of fibres. - Abstract: We introduce the atmospheric pressure plasma treatment as a suitable procedure for in-line industrial application of rabbit fibres pre-treatment. Changes of rabbit fibre properties due to the plasma treatment were studied in order to develop new technology of plasma-based treatment before felting. Diffuse Coplanar Surface Barrier Discharge (DCSBD) in ambient air at atmospheric pressure was used for plasma treatment. Scanning electron microscopy was used for determination of the fibres morphology before and after plasma treatment. X-ray photoelectron spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy were used for evaluation of reactive groups. The concentration of carbon decreased and conversely the concentration of nitrogen and oxygen increased after plasma treatment. Aging effect of plasma treated fibres was also investigated. Using Washburn method the significant increase of fibres wettability was observed after plasma treatment. New approach of pre-treatment of fibres before felting using plasma was developed. Plasma treatment of fibres at atmospheric pressure can replace the chemical method which consists of application of strong acids on fibres.

  4. Titanium nitride plasma-chemical synthesis with titanium tetrachloride raw material in the DC plasma-arc reactor

    Science.gov (United States)

    Kirpichev, D. E.; Sinaiskiy, M. A.; Samokhin, A. V.; Alexeev, N. V.

    2017-04-01

    The possibility of plasmochemical synthesis of titanium nitride is demonstrated in the paper. Results of the thermodynamic analysis of TiCl4 - H2 - N2 system are presented; key parameters of TiN synthesis process are calculated. The influence of parameters of plasma-chemical titanium nitride synthesis process in the reactor with an arc plasmatron on characteristics on the produced powders is experimentally investigated. Structure, chemical composition and morphology dependencies on plasma jet enthalpy, stoichiometric excess of hydrogen and nitrogen in a plasma jet are determined.

  5. Combustion flame-plasma hybrid reactor systems, and chemical reactant sources

    Science.gov (United States)

    Kong, Peter C

    2013-11-26

    Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

  6. Collector floating potentials in a discharge plasma

    International Nuclear Information System (INIS)

    Cercek, M.; Gyergyek, T.

    1999-01-01

    We present the results of a study on electrode floating potential formation in a hot-cathode discharge plasma. The electron component of the plasma is composed from two populations. The high temperature component develops from primary electrons and the cool component from secondary electrons born by ionisation of cold neutral gas. A static, kinetic plasma-sheath model is use to calculate the pre-sheath potential and the floating potential of the electrode. For hot primary electrons a truncated Maxwellian distribution is assumed. The plasma system is also modelled numerically with a dynamic, electrostatic particle simulation. The plasma source injects temporally equal fluxes of ions and electrons with half-Maxwellian velocities. Again, the hot electron distribution is truncated in the high velocity tail. The plasma parameters, such as ion temperature and mass, electron temperatures, discharge voltages, etc. correspond to experimental values. The experimental measurements of the electrode floating potential are performed in weakly magnetised plasma produced with hot cathode discharge in argon gas. Theoretical, simulation and experimental results are compared and they agree very well.(author)

  7. Injection of auxiliary electrons for increasing the plasma density in highly charged and high intensity ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Odorici, F., E-mail: fabrizio.odorici@bo.infn.it; Malferrari, L.; Montanari, A. [INFN—Bologna, Viale B. Pichat, 6/2, 40127 Bologna (Italy); Rizzoli, R. [INFN—Bologna, Viale B. Pichat, 6/2, 40127 Bologna (Italy); CNR–Istituto per la Microelettronica ed i Microsistemi, Via Gobetti 101, 40129 Bologna (Italy); Mascali, D.; Castro, G.; Celona, L.; Gammino, S.; Neri, L. [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy)

    2016-02-15

    Different electron guns based on cold- or hot-cathode technologies have been developed since 2009 at INFN for operating within ECR plasma chambers as sources of auxiliary electrons, with the aim of boosting the source performances by means of a higher plasma lifetime and density. Their application to microwave discharge ion sources, where plasma is not confined, has required an improvement of the gun design, in order to “screen” the cathode from the plasma particles. Experimental tests carried out on a plasma reactor show a boost of the plasma density, ranging from 10% to 90% when the electron guns are used, as explained by plasma diffusion models.

  8. Injection of auxiliary electrons for increasing the plasma density in highly charged and high intensity ion sources.

    Science.gov (United States)

    Odorici, F; Malferrari, L; Montanari, A; Rizzoli, R; Mascali, D; Castro, G; Celona, L; Gammino, S; Neri, L

    2016-02-01

    Different electron guns based on cold- or hot-cathode technologies have been developed since 2009 at INFN for operating within ECR plasma chambers as sources of auxiliary electrons, with the aim of boosting the source performances by means of a higher plasma lifetime and density. Their application to microwave discharge ion sources, where plasma is not confined, has required an improvement of the gun design, in order to "screen" the cathode from the plasma particles. Experimental tests carried out on a plasma reactor show a boost of the plasma density, ranging from 10% to 90% when the electron guns are used, as explained by plasma diffusion models.

  9. Time-resolved resonance fluorescence spectroscopy for study of chemical reactions in laser-induced plasmas.

    Science.gov (United States)

    Liu, Lei; Deng, Leimin; Fan, Lisha; Huang, Xi; Lu, Yao; Shen, Xiaokang; Jiang, Lan; Silvain, Jean-François; Lu, Yongfeng

    2017-10-30

    Identification of chemical intermediates and study of chemical reaction pathways and mechanisms in laser-induced plasmas are important for laser-ablated applications. Laser-induced breakdown spectroscopy (LIBS), as a promising spectroscopic technique, is efficient for elemental analyses but can only provide limited information about chemical products in laser-induced plasmas. In this work, time-resolved resonance fluorescence spectroscopy was studied as a promising tool for the study of chemical reactions in laser-induced plasmas. Resonance fluorescence excitation of diatomic aluminum monoxide (AlO) and triatomic dialuminum monoxide (Al 2 O) was used to identify these chemical intermediates. Time-resolved fluorescence spectra of AlO and Al 2 O were used to observe the temporal evolution in laser-induced Al plasmas and to study their formation in the Al-O 2 chemistry in air.

  10. Buffalo plasma fibronectin: a physico-chemical study.

    Science.gov (United States)

    Ahmed, N; Chandra, R; Raj, H G

    2001-12-01

    Plasma fibronectin (FN) of buffalo (Babulis babulis) was purified to apparent homogeneity, using gelatin-Sepharose and heparin-Sepharose affinity columns. It was found to have two subunits of molecular mass 246 kDa and 228 kDa, on SDS-gel. Its immunological cross-reactivity with anti-human plasma FN was confirmed by Western blotting. The amino acid composition was found to be similar to that of human and bovine plasma FNs. Buffalo plasma FN contained 2.23% neutral hexoses and 1.18% sialic acids. No titrable sulfhydryl group could be detected in the absence of denaturant. Reaction with DTNB indicated 3.4 sulfhydryl groups in the molecule, whereas BDC-OH titration gave a value of 3.8 -SH groups in buffalo plasma FN. Stoke's radius, intrinsic viscosity, diffusion coefficient and frictional ratio indicated that buffalo plasma FN did not have a compact globular conformation at physiological pH and ionic strength. Molecular dimensions (average length, 120 nm; molar mass to length ratio, 3950 nm(-1) and mean diameter, 2.4 nm) as revealed by rotary shadowing electron microscopy further supported the extended conformation of buffalo plasma FN. These results show that buffalo plasma FN has similar properties as that of human plasma FN.

  11. RF-plasma vapor deposition of siloxane on paper. Part 2: Chemical evolution of paper surface

    International Nuclear Information System (INIS)

    Sahin, Halil Turgut

    2013-01-01

    Highlights: ► Investigate the detailed RF-cold plasma surface modified paper by XPS and ATR-FTIR. ► Some chemical analysis of RF-cold plasma surface modified paper after RF plasma treatment. ► Identify the connection between RF plasma treatment and the surface chemistry of paper surface. - Abstract: Survey and high-resolution (HR) XPS studies indicate that OMCTSO plasma treatment created a new silicon containing functional groups and changed the hydroxyl content on the surface of paper. Four intense survey XPS spectrum peaks were observed for the OMCTSO plasma treated paper. They were the Si 2p at 100 eV, Si 2s at 160 eV, C 1s at 285 eV, and O 1s at 525 eV for the plasma modified surface. It was realized that the macromolecular chain-breaking mechanisms and plasma-induced etching processes control the number and the availability of OH-functionalities during OMCTSO plasma exposure on paper. The reaction, initiated by these species, depends mainly on the nature of chemicals in the plasma as well as on the energy level of the plasma and the nature of the surface effects in the modification of the paper. The ATR-FTIR spectrum of paper treated with OMCTSO plasma has characteristic absorption bands attributed to the Si-O and Si-O-Si formations on the surface.

  12. Liquid assisted plasma enhanced chemical vapour deposition with a non-thermal plasma jet at atmospheric pressure

    Czech Academy of Sciences Publication Activity Database

    Schäfer, J.; Fricke, K.; Mika, Filip; Pokorná, Zuzana; Zajíčková, L.; Foest, R.

    2017-01-01

    Roč. 630, MAY 30 (2017), s. 71-78 ISSN 0040-6090 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : plasma jet * liquid assisted plasma enhanced chemical * vapour deposition * silicon oxide Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Coating and films Impact factor: 1.879, year: 2016

  13. Temperature dependence on plasma-induced damage and chemical reactions in GaN etching processes using chlorine plasma

    Science.gov (United States)

    Liu, Zecheng; Ishikawa, Kenji; Imamura, Masato; Tsutsumi, Takayoshi; Kondo, Hiroki; Oda, Osamu; Sekine, Makoto; Hori, Masaru

    2018-06-01

    Plasma-induced damage (PID) on GaN was optimally reduced by high-temperature chlorine plasma etching. Energetic ion bombardments primarily induced PID involving stoichiometry, surface roughness, and photoluminescence (PL) degradation. Chemical reactions under ultraviolet (UV) irradiation and chlorine radical exposure at temperatures higher than 400 °C can be controlled by taking into account the synergism of simultaneous photon and radical irradiations to effectively reduce PID.

  14. Applications of non-equilibrium plasma in chemical processes

    International Nuclear Information System (INIS)

    Patino, P.; Castro, A.

    2003-01-01

    By means of optical emission spectroscopy the population of O( 3 P) in a non-equilibrium, high voltage, oxygen plasma, and O( 3 P), H and OH in another of steam in radio frequency, have been followed. Reactions of both plasmas with liquid hydrocarbons have produced oxidation and/or hydrogenation, depending on the conditions of each one. (Author)

  15. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    International Nuclear Information System (INIS)

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-01-01

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application

  16. Remote plasma-enhanced metalorganic chemical vapor deposition of aluminum oxide thin films

    NARCIS (Netherlands)

    Volintiru, I.; Creatore, M.; Hemmen, van J.L.; Sanden, van de M.C.M.

    2008-01-01

    Aluminum oxide films were deposited using remote plasma-enhanced metalorganic chemical vapor deposition from oxygen/trimethylaluminum mixtures. Initial studies by in situ spectroscopic ellipsometry demonstrated that the aluminum oxide films deposited at temperatures

  17. Plasma-enhanced chemical vapor deposition of aluminum oxide using ultrashort precursor injection pulses

    NARCIS (Netherlands)

    Dingemans, G.; Sanden, van de M.C.M.; Kessels, W.M.M.

    2012-01-01

    An alternative plasma-enhanced chemical vapor deposition (PECVD) method is developed and applied for the deposition of high-quality aluminum oxide (AlOx) films. The PECVD method combines a continuous plasma with ultrashort precursor injection pulses. We demonstrate that the modulation of the

  18. The Chemical Potential of Plasma Membrane Cholesterol: Implications for Cell Biology.

    Science.gov (United States)

    Ayuyan, Artem G; Cohen, Fredric S

    2018-02-27

    Cholesterol is abundant in plasma membranes and exhibits a variety of interactions throughout the membrane. Chemical potential accounts for thermodynamic consequences of molecular interactions, and quantifies the effective concentration (i.e., activity) of any substance participating in a process. We have developed, to our knowledge, the first method to measure cholesterol chemical potential in plasma membranes. This was accomplished by complexing methyl-β-cyclodextrin with cholesterol in an aqueous solution and equilibrating it with an organic solvent containing dissolved cholesterol. The chemical potential of cholesterol was thereby equalized in the two phases. Because cholesterol is dilute in the organic phase, here activity and concentration were equivalent. This equivalence allowed the amount of cholesterol bound to methyl-β-cyclodextrin to be converted to cholesterol chemical potential. Our method was used to determine the chemical potential of cholesterol in erythrocytes and in plasma membranes of nucleated cells in culture. For erythrocytes, the chemical potential did not vary when the concentration was below a critical value. Above this value, the chemical potential progressively increased with concentration. We used standard cancer lines to characterize cholesterol chemical potential in plasma membranes of nucleated cells. This chemical potential was significantly greater for highly metastatic breast cancer cells than for nonmetastatic breast cancer cells. Chemical potential depended on density of the cancer cells. A method to alter and fix the cholesterol chemical potential to any value (i.e., a cholesterol chemical potential clamp) was also developed. Cholesterol content did not change when cells were clamped for 24-48 h. It was found that the level of activation of the transcription factor STAT3 increased with increasing cholesterol chemical potential. The cholesterol chemical potential may regulate signaling pathways. Copyright © 2018. Published by

  19. Study on stability of a-SiCOF films deposited by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Ding Shijin; Zhang Qingquan; Wang Pengfei; Zhang Wei; Wang Jitao

    2001-01-01

    Low-dielectric-constant a-SiCOF films have been prepared from TEOS, C 4 F 8 and Ar by using plasma enhanced chemical vapor deposition method. With the aid of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), the chemical bonding configuration, thermal stability and resistance to water of the films are explored

  20. Inactivation of Escherichia coli on blueberries using cold plasma with chemical augmentation inside a partial vacuum

    Science.gov (United States)

    Justification: The mechanism by which cold plasma inactivates pathogens is through the production of free reactive chemical species. Unfortunately, the most reactive chemical species have the shortest half-life. In a vacuum their half-life is believed to be prolonged. Additionally, these reactive sp...

  1. Chemical modeling of a high-density inductively-coupled plasma reactor containing silane

    NARCIS (Netherlands)

    Kovalgin, Alexeij Y.; Boogaard, A.; Brunets, I.; Holleman, J.; Schmitz, Jurriaan

    We carried out the modeling of chemical reactions in a silane-containing remote Inductively Coupled Plasma Enhanced Chemical Vapor Deposition (ICPECVD) system, intended for deposition of silicon, silicon oxide, and silicon nitride layers. The required electron densities and Electron Energy

  2. Chemical reactions inside the plasma chamber of the SEAFP reactor plant models

    International Nuclear Information System (INIS)

    Gay, J.M.; Ebert, E.; Mazille, F.

    1995-01-01

    Loss of coolant or loss of vacuum accidents may lead to chemical reactions between the protecting materials of the plasma facing components and air or water. A production of energy, reaction products and hydrogen may be induced. The paper defines the operating conditions and chemical reactions and presents the main results from the underlying studies. (orig.)

  3. Plasma waves observed by sounding rockets

    International Nuclear Information System (INIS)

    Kimura, I.

    1977-01-01

    Observations of plasma wave phenomena have been conducted with several rockets launched at Kagoshima Space Center, Kyushu, Japan, and at Showa Base, Antarctica. This report presents some results of the observations in anticipation of having valuable comments from other plasma physicists, especially from those who are concerned with laboratory plasma. In the K-9M-41 rocket experiment, VLF plasma waves were observed. In this experiment, the electron beam of several tens of uA was emitted from a hot cathode when a positive dc bias changing from 0 to 10V at 1V interval each second was applied to a receiving dipole antenna. The discrete emissions with 'U' shaped frequency spectrum were observed for the dc bias over 3 volts. The U emissions appeared twice per spin period of the rocket. Similar rocket experiment was performed at Showa Base using a loop and dipole antenna and without hot cathode. Emissions were observed with varying conditions. At present, the authors postulate that such emissions may be produced just in the vicinity of a rocket due to a kind of wake effect. (Aoki, K.)

  4. Modification of optical and electrical properties of chemical bath deposited CdS using plasma treatments

    International Nuclear Information System (INIS)

    Gonzalez, G.; Krishnan, B.; Avellaneda, D.; Castillo, G. Alan; Das Roy, T.K.; Shaji, S.

    2011-01-01

    Cadmium sulphide (CdS) is a well known n-type semiconductor that is widely used in solar cells. Here we report preparation and characterization of chemical bath deposited CdS thin films and modification of their optical and electrical properties using plasma treatments. CdS thin films were prepared from a chemical bath containing Cadmium chloride, Triethanolamine and Thiourea under various deposition conditions. Good quality thin films were obtained during deposition times of 5, 10 and 15 min. CdS thin films prepared for 10 min. were treated using a glow discharge plasma having nitrogen and argon carrier gases. The changes in morphology, optical and electrical properties of these plasma treated CdS thin films were analyzed in detail. The results obtained show that plasma treatment is an effective technique in modification of the optical and electrical properties of chemical bath deposited CdS thin films.

  5. Modification of optical and electrical properties of chemical bath deposited CdS using plasma treatments

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, G. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); CIIDIT, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Avellaneda, D.; Castillo, G. Alan; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P 66450 (Mexico); CIIDIT, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2011-08-31

    Cadmium sulphide (CdS) is a well known n-type semiconductor that is widely used in solar cells. Here we report preparation and characterization of chemical bath deposited CdS thin films and modification of their optical and electrical properties using plasma treatments. CdS thin films were prepared from a chemical bath containing Cadmium chloride, Triethanolamine and Thiourea under various deposition conditions. Good quality thin films were obtained during deposition times of 5, 10 and 15 min. CdS thin films prepared for 10 min. were treated using a glow discharge plasma having nitrogen and argon carrier gases. The changes in morphology, optical and electrical properties of these plasma treated CdS thin films were analyzed in detail. The results obtained show that plasma treatment is an effective technique in modification of the optical and electrical properties of chemical bath deposited CdS thin films.

  6. A study of the potential of plasma processing in the chemical industry

    International Nuclear Information System (INIS)

    Estey, P.N.; Connolly, T.J.

    1984-01-01

    This work describes a systematic approach to determine the potential for plasma processing in the United States chemical industry. A model was developed that describes the physical inputs and outputs from a plasma based processing system. Based on these mass flows and the energy flows to the processor an economic assessment of the plasma processing system is made. This economic assessment which also includes the capital costs of the processor, can be used to determine if the plasma system is competitive with the conventional system

  7. Comparative studies of chemically synthesized and RF plasma ...

    Indian Academy of Sciences (India)

    journal of. April 2015 physics pp. 653–665. Comparative studies of ... MS received 16 April 2013; revised 5 February 2014; accepted 28 May 2014 ... RF plasma polymerization; poly(o-toluidine); Fourier transform infrared; UV–visible ... tial applications, e.g., as electrodes and membranes for electrochemical energy ...

  8. Experimental setup for producing tungsten coated graphite tiles using plasma enhanced chemical vapor deposition technique for fusion plasma applications

    International Nuclear Information System (INIS)

    Chauhan, Sachin Singh; Sharma, Uttam; Choudhary, K.K.; Sanyasi, A.K.; Ghosh, J.; Sharma, Jayshree

    2013-01-01

    Plasma wall interaction (PWI) in fusion grade machines puts stringent demands on the choice of materials in terms of high heat load handling capabilities and low sputtering yields. Choice of suitable material still remains a challenge and open topic of research for the PWI community. Carbon fibre composites (CFC), Beryllium (Be), and Tungsten (W) are now being considered as first runners for the first wall components of future fusion machines. Tungsten is considered to be one of the suitable materials for the job because of its superior properties than carbon like low physical sputtering yield and high sputter energy threshold, high melting point, fairly high re-crystallization temperature, low fuel retention capabilities, low chemical sputtering with hydrogen and its isotopes and most importantly the reparability with various plasma techniques both ex-situ and in-situ. Plasma assisted chemical vapour deposition is considered among various techniques as the most preferable technique for fabricating tungsten coated graphite tiles to be used as tokamak first wall and target components. These coated tiles are more favourable compared to pure tungsten due to their light weight and easier machining. A system has been designed, fabricated and installed at SVITS, Indore for producing tungsten coated graphite tiles using Plasma Enhanced Chemical Vapor Deposition (PE-CVD) technique for Fusion plasma applications. The system contains a vacuum chamber, a turbo-molecular pump, two electrodes, vacuum gauges, mass analyzer, mass flow controllers and a RF power supply for producing the plasma using hydrogen gas. The graphite tiles will be put on one of the electrodes and WF6 gas will be inserted in a controlled manner in the hydrogen plasma to achieve the tungsten-coating with WF6 dissociation. The system is integrated at SVITS, Indore and a vacuum of the order of 3*10 -6 is achieved and glow discharge plasma has been created to test all the sub-systems. The system design with

  9. [Distribution of chemical elements in whole blood and plasma].

    Science.gov (United States)

    Barashkov, G K; Zaĭtseva, L I; Kondakhchan, M A; Konstantinova, E A

    2003-01-01

    The distribution factor (Fd) of 35 elements of plasma and whole blood in 26 healthy men and women was detected by ICP-OES. Usilig this parameter the elements were subdivided in 3 pools. 9 of them have Fd higher than 1.5 ("elements of plasma"-Ag, Ca, Cu, In, Li, Na, Se, Si, Sr); 6 have lower than 0.5 ("elements of blood cells"-Fe, K, Mn, Ni, V, Zn), other 20-about 1 ("blood elements"). Fd of all elements depends on ionic radius. Elements of 2nd sub-groups of all groups of Mendeleev's periodic table ("heavy metals") depend on the similar law: "with growing of ionic radius the concentration of elements in plasma enhances". In alkaline metals Fd depends on the opposite law:" with growing of ionic radius of alkaline metal the quantity of elements in blood cells enhance". Dependence of Fd on the value of atomic mass in periods or in exterior electronic cloud (s-, p-, d-, f-) was not established. The table of distribution of all detected elements in whole blood in relation to 8 macroelements (Ca, Mg, K, Na, S, P, Fe, Zn,) is presented, as a basic diagnostic criteria in metal-ligand homeostasis disturbance.

  10. Improvement of Plating Characteristics Between Nickel and PEEK by Plasma Treatment and Chemical Etching

    International Nuclear Information System (INIS)

    Lee, Hye W.; Lee, Jong K.; Park, Ki Y.

    2009-01-01

    Surface of PEEK(poly-ether-ether-ketone) was modified by chemical etching, plasma treatment and mechanical grinding to improve the plating adhesion. The plating characteristics of these samples were studied by the contact angle, plating thickness, gloss and adhesion. Chemical etching and plasma treatment increased wettability, adhesion and gloss. The contact angle of as-received PEEK was 61 .deg. . The contact angles of chemical etched, plasma treated or both were improved to the range of 15∼33 .deg. . In the case of electroless plating, the thickest layer without blister was 1.6 μm. The adhesion strengths by chemical etching, plasma treatment or both chemical etching and plasma treatment were 75 kgf/cm 2 , 102 kgf/cm 2 , 113 kgf/cm 2 , respectively, comparing to the 24 kgf/cm 2 of as-received. In the case of mechanically ground PEEKs, the adhesion strengths were higher than those unground, with the sacrifice of surface gloss. The gloss of untreated PEEK were greater than mechanically ground PEEKs. Plating thickness increased linearly with the plating times

  11. Oxygen Barrier Coating Deposited by Novel Plasma-enhanced Chemical Vapor Deposition

    DEFF Research Database (Denmark)

    Jiang, Juan; Benter, M.; Taboryski, Rafael Jozef

    2010-01-01

    We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source. This confi......We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source...... effect of single-layer coatings deposited under different reaction conditions was studied. The coating thickness and the carbon content in the coatings were found to be the critical parameters for the barrier property. The novel barrier coating was applied on different polymeric materials...

  12. Understanding plasma spraying process and characteristics of DC-arc plasma gun (PJ-100

    Directory of Open Access Journals (Sweden)

    Jovana Ružić

    2012-12-01

    Full Text Available The thermal spray processes are a group of coating processes used to apply metallic or non-metallic coatings. In these processes energy sources are used to heat the coating material (in the form of powder, wire, or rod form to a molten or semi-molten state and accelerated towards a prepared surface by either carrier gases or atomization jets. In plasma spraying process, the spraying material is generally in the form of powder and requires a carrier gas to feed the powder into the plasma jet, which is passing between the hot cathode and the cylindrical nozzle-shaped anode. The design of DC plasma gun (PJ - 100 is designed and manufactured in Serbia. Plasma spaying process, the powder injection with the heat, momentum and mass transfers between particles and plasma jet, and the latest developments related to the production of DC plasma gun are described in this article.

  13. Radioimmunoassay and chemical ionization/mass spectrometry compared for plasma cortisol determination

    International Nuclear Information System (INIS)

    Lindberg, C.; Johnson, S.; Hedner, P.; Gustafsson, A.

    1982-01-01

    A method is described for determination of cortisol in plasma and urine, based on chemical ionization/mass spectrometry with deuterium-labeled cortisol as the internal standard. The within-run precision (CV) was 2.5-5.7%, the between-run precision 4.6%. Results by this method were compared with those by a radioimmunological method (RIANEN Cortisol, New England Nuclear) for 395 plasma samples. The latter method gave significantly higher (approx. 25%) cortisol values

  14. The Synergistic Effect between Electrical and Chemical Factors in Plasma Gene/Molecule-Transfection

    Science.gov (United States)

    Jinno, Masafumi

    2016-09-01

    This study has been done to know what kind of factors in plasma and processes on cells promote plasma gene/molecule transfection. We have discovered a new plasma source using a microcapillary electrode which enables high transfection efficiency and high cell survivability simultaneously. However, the mechanism of the transfection by plasma was not clear. To clarify the transfection mechanisms by micro plasma, we focused on the effects of electrical (current, charge, field, etc.) and chemical (radicals, RONS, etc.) factors generated by the micro plasma and evaluated the contribution weight of three groups of the effects and processes, i.e. electrical, chemical and biochemical ones. At first, the necessity of the electrical factors was estimated by the laser produced plasma (LPP). Mouse L-929 fibroblast cell was cultured on a 96-well plate or 12-well micro slide chamber. Plasmids pCX-EGFP in Tris-EDTA buffer was dropped on the cells and they were exposed to the capillary discharge plasma (CDP) or the LPP. In the case of the CDP, the plasma was generated between the tip of the capillary electrode and the cells so that both electrical and chemical factors were supplied to the cells. In this setup, about 20% of average transfection efficiency was obtained. In the case of the LPP, the plasma was generated apart from the cells so that electrical factors were not supplied to the cells. In this setup, no transfection was observed. These results show that the electrical factors are necessary for the plasma gene transfection. Next, the necessity of the chemical factors was estimated the effect of catalase to remove H2O2 in CDP. The transfection efficiency decreased to 0.4 by scavenging H2O2 with catalase. However, only the solution of H2O2 caused no gene transfection in cells. These results shows that H2O2 is important species to cause gene/molecule transfection but still needs a synergistic effect with electrical or other chemical factors. This work was partly supported by

  15. Fundamental limits on gas-phase chemical reduction of NOx in a plasma

    Energy Technology Data Exchange (ETDEWEB)

    Penetrante, B.M.; Hsiao, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

    1997-12-31

    In the plasma, the electrons do not react directly with the NOx molecules. The electrons collide mainly with the background gas molecules like N{sub 2}, O{sub 2} and H{sub 2}O. Electron impact on these molecules result partly in dissociation reactions that produce reactive species like N, O and OH. The NOx in the engine exhaust gas initially consist mostly of NO. The ground state nitrogen atom, N, is the only species that could lead to the chemical reduction of NO to N{sub 2}. The O radical oxidizes NO to NO{sub 2} leaving the same amount of NOx. The OH radical converts NO{sub 2} to nitric acid. Acid products in the plasma can easily get adsorbed on surfaces in the plasma reactor and in the pipes. When undetected, the absence of these oxidation products can often be mistaken for chemical reduction of NOx. In this paper the authors will examine the gas-phase chemical reduction of NOx. They will show that under the best conditions, the plasma can chemically reduce 1.6 grams of NOx per brake-horsepower-hour [g(NOx)/bhp-hr] when 5% of the engine output energy is delivered to the plasma.

  16. Diffusion in plasma: The Hall effect, compositional waves, and chemical spots

    Energy Technology Data Exchange (ETDEWEB)

    Urpin, V., E-mail: Vadim.urpin@uv.es [Ioffe Institute of Physics and Technology (Russian Federation)

    2017-03-15

    Diffusion caused by a combined influence of the electric current and Hall effect is considered, and it is argued that such diffusion can form inhomogeneities of a chemical composition in plasma. The considered mechanism can be responsible for the formation of element spots in laboratory and astrophysical plasmas. This current-driven diffusion can be accompanied by propagation of a particular type of waves in which the impurity number density oscillates alone. These compositional waves exist if the magnetic pressure in plasma is much greater than the gas pressure.

  17. A two-temperature chemical non-equilibrium modeling of DC arc plasma

    International Nuclear Information System (INIS)

    Qian Haiyang; Wu Bin

    2011-01-01

    To a better understanding of non-equilibrium characteristics of DC arc plasma,a two-dimensional axisymmetric two-temperature chemical non-equilibrium (2T-NCE) model is applied for direct current arc argon plasma generator with water-cooled constrictor at atmospheric pressure. The results show that the electron temperature and heavy particle temperature has a relationship under different working parameters, indicating that DC arc plasma has a strong non-equilibrium characteristic, and the variation is obvious. (authors)

  18. Development and Testing of a High Capacity Plasma Chemical Reactor in the Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, Raymond W.

    2012-07-30

    This project, Development and Testing of a High Capacity Plasma Chemical Reactor in the Ukraine was established at the Kharkiv Institute of Physics and Technology (KIPT). The associated CRADA was established with Campbell Applied Physics (CAP) located in El Dorado Hills, California. This project extends an earlier project involving both CAP and KIPT conducted under a separate CRADA. The initial project developed the basic Plasma Chemical Reactor (PCR) for generation of ozone gas. This project built upon the technology developed in the first project, greatly enhancing the output of the PCR while also improving reliability and system control.

  19. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    Energy Technology Data Exchange (ETDEWEB)

    Hamaguchi, Satoshi [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-07-11

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed.

  20. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    International Nuclear Information System (INIS)

    Hamaguchi, Satoshi

    2013-01-01

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed

  1. Plasma-enhanced chemical vapor deposition for YBCO film fabrication of superconducting fault-current limiter

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Byung Hyuk; Kim, Chan Joong

    2006-05-15

    Since the high-temperature superconductor of oxide type was founded, many researches and efforts have been performed for finding its application field. The YBCO superconducting film fabricated on economic metal substrate with uniform critical current density is considered as superconducting fault-current limiter (SFCL). There are physical and chemical processes to fabricate superconductor film, and it is understood that the chemical methods are more economic to deposit large area. Among them, chemical vapor deposition (CVD) is a promising deposition method in obtaining film uniformity. To solve the problems due to the high deposition temperature of thermal CVD, plasma-enhanced chemical vapor deposition (PECVD) is suggested. This report describes the principle and fabrication trend of SFCL, example of YBCO film deposition by PECVD method, and principle of plasma deposition.

  2. Studies on plasma profiles and its effect on dust charging in hydrogen plasma

    Science.gov (United States)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhay, M.

    2010-02-01

    Plasma profiles and its influence on dust charging are studied in hydrogen plasma. The plasma is produced in a high vacuum device by a hot cathode discharge method and is confined by a cusped magnetic field cage. A cylindrical Espion advanced Langmuir probe having 0.15 mm diameter and 10.0 mm length is used to study the plasma parameters for various discharge conditions. Optimum operational discharge parameters in terms of charging of the dust grains are studied. The charge on the surface of the dust particle is calculated from the capacitance model and the current by the dust grains is measured by the combination of a Faraday cup and an electrometer. Unlike our previous experiments in which dust grains were produced in-situ, here a dust dropper is used to drop the dust particles into the plasma.

  3. Studies on plasma profiles and its effect on dust charging in hydrogen plasma

    International Nuclear Information System (INIS)

    Kakati, B; Kausik, S S; Saikia, B K; Bandyopadhay, M

    2010-01-01

    Plasma profiles and its influence on dust charging are studied in hydrogen plasma. The plasma is produced in a high vacuum device by a hot cathode discharge method and is confined by a cusped magnetic field cage. A cylindrical Espion advanced Langmuir probe having 0.15 mm diameter and 10.0 mm length is used to study the plasma parameters for various discharge conditions. Optimum operational discharge parameters in terms of charging of the dust grains are studied. The charge on the surface of the dust particle is calculated from the capacitance model and the current by the dust grains is measured by the combination of a Faraday cup and an electrometer. Unlike our previous experiments in which dust grains were produced in-situ, here a dust dropper is used to drop the dust particles into the plasma.

  4. Patterned growth of carbon nanotubes obtained by high density plasma chemical vapor deposition

    Science.gov (United States)

    Mousinho, A. P.; Mansano, R. D.

    2015-03-01

    Patterned growth of carbon nanotubes by chemical vapor deposition represents an assembly approach to place and orient nanotubes at a stage as early as when they are synthesized. In this work, the carbon nanotubes were obtained at room temperature by High Density Plasmas Chemical Vapor Deposition (HDPCVD) system. This CVD system uses a new concept of plasma generation, where a planar coil coupled to an RF system for plasma generation was used with an electrostatic shield for plasma densification. In this mode, high density plasmas are obtained. We also report the patterned growth of carbon nanotubes on full 4-in Si wafers, using pure methane plasmas and iron as precursor material (seed). Photolithography processes were used to pattern the regions on the silicon wafers. The carbon nanotubes were characterized by micro-Raman spectroscopy, the spectra showed very single-walled carbon nanotubes axial vibration modes around 1590 cm-1 and radial breathing modes (RBM) around 120-400 cm-1, confirming that high quality of the carbon nanotubes obtained in this work. The carbon nanotubes were analyzed by atomic force microscopy and scanning electron microscopy too. The results showed that is possible obtain high-aligned carbon nanotubes with patterned growth on a silicon wafer with high reproducibility and control.

  5. Expanding thermal plasma chemical vapour deposition of ZnO:Al layers for CIGS solar cells

    NARCIS (Netherlands)

    Sharma, K.; Williams, B.L.; Mittal, A.; Knoops, H.C.M.; Kniknie, B.J.; Bakker, N.J.; Kessels, W.M.M.; Schropp, R.E.I.; Creatore, M.

    2014-01-01

    Aluminium-doped zinc oxide (ZnO:Al) grown by expanding thermal plasma chemical vapour deposition (ETP-CVD) has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing

  6. Chemically different non-thermal plasmas target distinct cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Lunov, O.; Zablotskyy, V.; Chrupina, O.; Lunova, M.; Jirsa, M.; Dejneka, A.; Kubinová, Šárka

    2017-01-01

    Roč. 7, apr (2017), s. 600 ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : chemically different * non-thermal plasmas * target distinct cell death pathways Subject RIV: FP - Other Medical Disciplines OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  7. Plasma for electrification of chemical industry : a case study on CO2 reduction

    NARCIS (Netherlands)

    Van Rooij, G.J.; Akse, H.N.; Bongers, W.A.; Van De Sanden, M.C.M.

    2018-01-01

    Significant growth of the share of (intermittent) renewable power in the chemical industry is imperative to meet increasingly stricter limits on CO2 exhaust that are being implemented within Europe. This paper aims to evaluate the potential of a plasma process that converts input CO2 into a pure

  8. Plasma for Electrification of Chemical Industry: a Case Study on CO2 Reduction

    NARCIS (Netherlands)

    van Rooij, G. J.; Akse, H.; Bongers, W.; van de Sanden, M. C. M.

    2018-01-01

    Significantly increasing the share of (intermittent) renewable power in the chemical industry is imperative to meet increasingly stricter limits on CO2 exhaust that are being implemented within Europe. This paper aims to evaluate the potential of a plasma process that converts input CO2 into a pure

  9. Plasma enhanced chemical vapor deposition silicon oxynitride optimized for application in integrated optics

    NARCIS (Netherlands)

    Worhoff, Kerstin; Driessen, A.; Lambeck, Paul; Hilderink, L.T.H.; Linders, Petrus W.C.; Popma, T.J.A.

    1999-01-01

    Silicon Oxynitride layers are grown from SiH4/N2, NH3 and N2O by Plasma Enhanced Chemical Vapor Deposition. The process is optimized with respect to deposition of layers with excellent uniformity in the layer thickness, high homogeneity of the refractive index and good reproducibility of the layer

  10. Destruction of chemical warfare surrogates using a portable atmospheric pressure plasma jet

    Science.gov (United States)

    Škoro, Nikola; Puač, Nevena; Živković, Suzana; Krstić-Milošević, Dijana; Cvelbar, Uroš; Malović, Gordana; Petrović, Zoran Lj.

    2018-01-01

    Today's reality is connected with mitigation of threats from the new chemical and biological warfare agents. A novel investigation of cold plasmas in contact with liquids presented in this paper demonstrated that the chemically reactive environment produced by atmospheric pressure plasma jet (APPJ) is potentially capable of rapid destruction of chemical warfare agents in a broad spectrum. The decontamination of three different chemical warfare agent surrogates dissolved in liquid is investigated by using an easily transportable APPJ. The jet is powered by a kHz signal source connected to a low-voltage DC source and with He as working gas. The detailed investigation of electrical properties is performed for various plasmas at different distances from the sample. The measurements of plasma properties in situ are supported by the optical spectrometry measurements, whereas the high performance liquid chromatography measurements before and after the treatment of aqueous solutions of Malathion, Fenitrothion and Dimethyl Methylphosphonate. These solutions are used to evaluate destruction and its efficiency for specific neural agent simulants. The particular removal rates are found to be from 56% up to 96% during 10 min treatment. The data obtained provide basis to evaluate APPJ's efficiency at different operating conditions. The presented results are promising and could be improved with different operating conditions and optimization of the decontamination process.

  11. Achieving uniform layer deposition by atmospheric-pressure plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Ok [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Kang, Woo Seok, E-mail: kang@kimm.re.kr [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Department of Environment & Energy Mechanical Engineering, University of Science & Technology (UST), Daejeon 305-350 (Korea, Republic of); Hur, Min; Lee, Jin Young [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Song, Young-Hoon [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Department of Environment & Energy Mechanical Engineering, University of Science & Technology (UST), Daejeon 305-350 (Korea, Republic of)

    2015-12-31

    This work investigates the use of plasma-enhanced chemical vapor deposition under atmospheric pressure for achieving uniform layer formation. Electrical and optical measurements demonstrated that the counterbalance between oxygen and precursors maintained the homogeneous discharge mode, while creating intermediate species for layer deposition. Several steps of the deposition process of the layers, which were processed on a stationary stage, were affected by flow stream and precursor depletion. This study showed that by changing the flow streamlines using substrate stage motion uniform layer deposition under atmospheric pressure can be achieved. - Highlights: • Zirconium oxide was deposited by atmospheric-pressure plasma-enhanced chemical vapor deposition. • Homogeneous plasma was maintained by counterbalancing between discharge gas and precursors. • Several deposition steps were observed affected by the gas flow stream and precursor depletion. • Thin film layer was uniformly grown when the substrate underwent a sweeping motion.

  12. Electronic radiation of a plasma in a magnetic field

    International Nuclear Information System (INIS)

    Canobbio, E.; Consoli, T.; Ichtchenko, G.; Parlance, F.

    1965-01-01

    The influence on the microwave spectrum of the number of fast electrons, density, pressure and plasma inhomogeneities, has been studied in a hot cathode reflex discharge, operating either in a steady state either in a pulsed regime. Under some conditions a strong emission is observed between the harmonics of the electron gyrofrequency. A theoretical interpretation of the results is advanced by extending a model already proposed by CANOBBIO and CROCI. In particular it is indicated that the transition radiation can be responsible for the emission observed between the harmonics. (authors) [fr

  13. Determination of clebopride in plasma by capillary gas chromatography-negative-ion chemical ionization mass spectrometry.

    Science.gov (United States)

    Robinson, P R; Jones, M D; Maddock, J

    1988-11-18

    A procedure for the analysis of clebopride in plasma using capillary gas chromatography-negative-ion chemical ionization mass spectrometry has been developed. Employing an ethoxy analogue as internal standard, the two compounds were extracted from basified plasma using dichloromethane. Subsequent reaction with heptafluorobutyryl imidazole produced volatile monoheptafluorobutyryl derivatives whose ammonia negative-ion mass spectra proved ideal for selected-ion monitoring. The recovery of clebopride from plasma at 0.536 nmol/l was found to be 85.5 +/- 0.9% (n = 3) whilst measurement down to 0.268 nmol/l was possible with a coefficient of variation of 7.9%. Plasma levels of the compound are reported in two volunteers following ingestion of 1 mg of clebopride as the malate salt.

  14. Two dimensional radial gas flows in atmospheric pressure plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae

    2017-12-01

    Atmospheric pressure (AP) operation of plasma-enhanced chemical vapor deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial pressure, hydrogen partial pressure, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.

  15. Beam-plasma interaction with an electron beam injecting into a symmetrically open plasma system; Electron beam relaxation. Puchkovo-plazmennoe vzaimodejstvie pri inzhektsii ehlektronnogo puchka v simmetrichno otkrytuyu plazmennuyu sistemu; Relaksatsiya ehlektronnogo puchka

    Energy Technology Data Exchange (ETDEWEB)

    Opanasenko, A V; Romanyuk, L I [AN Ukrainskoj SSR, Kiev (Ukrainian SSR). Inst. Yadernykh Issledovanij

    1989-10-01

    The relaxation of the electron beam with the electron density of 1-2 keV injected through the symmetrically open plasma system with the independent hot cathode Penning discharge is experimentally investigated. It is shown that the velocity distribution function of the electron beam changes after passing each wave generation zone induced by the beam. The contribution of different wave zones to the beam relaxation depends on the prehistory of the beam-plasma interaction and may be regulated by the selection of the plasma system parameters. By this way the complete relaxation of the electron beam can be achieved after the beam crossing the whole system.

  16. Alternative model of space-charge-limited thermionic current flow through a plasma

    Science.gov (United States)

    Campanell, M. D.

    2018-04-01

    It is widely assumed that thermionic current flow through a plasma is limited by a "space-charge-limited" (SCL) cathode sheath that consumes the hot cathode's negative bias and accelerates upstream ions into the cathode. Here, we formulate a fundamentally different current-limited mode. In the "inverse" mode, the potentials of both electrodes are above the plasma potential, so that the plasma ions are confined. The bias is consumed by the anode sheath. There is no potential gradient in the neutral plasma region from resistivity or presheath. The inverse cathode sheath pulls some thermoelectrons back to the cathode, thereby limiting the circuit current. Thermoelectrons entering the zero-field plasma region that undergo collisions may also be sent back to the cathode, further attenuating the circuit current. In planar geometry, the plasma density is shown to vary linearly across the electrode gap. A continuum kinetic planar plasma diode simulation model is set up to compare the properties of current modes with classical, conventional SCL, and inverse cathode sheaths. SCL modes can exist only if charge-exchange collisions are turned off in the potential well of the virtual cathode to prevent ion trapping. With the collisions, the current-limited equilibrium must be inverse. Inverse operating modes should therefore be present or possible in many plasma devices that rely on hot cathodes. Evidence from past experiments is discussed. The inverse mode may offer opportunities to minimize sputtering and power consumption that were not previously explored due to the common assumption of SCL sheaths.

  17. The relationship between chemical structure and dielectric properties of plasma-enhanced chemical vapor deposited polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Hao [Materials Sci and Tech Applications, LLC, 409 Maple Springs Drive, Dayton OH 45458 (United States)]. E-mail: hao.jiang@wpafb.af.mil; Hong Lianggou [Materials Sci and Tech Applications, LLC, 409 Maple Springs Drive, Dayton OH 45458 (United States); Venkatasubramanian, N. [Research Institute, University of Dayton, 300 College Park, Dayton, OH 45469-0168 (United States); Grant, John T. [Research Institute, University of Dayton, 300 College Park, Dayton, OH 45469-0168 (United States); Eyink, Kurt [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States); Wiacek, Kevin [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson Air Force Base, OH 45433-7251 (United States); Fries-Carr, Sandra [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson Air Force Base, OH 45433-7251 (United States); Enlow, Jesse [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States); Bunning, Timothy J. [Air Force Research Laboratory, Materials Directorate, 3005 Hobson Way, Wright-Patterson Air Force Base, OH 45433-7707 (United States)

    2007-02-26

    Polymer dielectric films fabricated by plasma enhanced chemical vapor deposition (PECVD) have unique properties due to their dense crosslinked bulk structure. These spatially uniform films exhibit good adhesion to a variety of substrates, excellent chemical inertness, high thermal resistance, and are formed from an inexpensive, solvent-free, room temperature process. In this work, we studied the dielectric properties of plasma polymerized (PP) carbon-based polymer thin films prepared from two precursors, benzene and octafluorocyclobutane. Two different monomer feed locations, directly in the plasma zone or in the downstream region (DS) and two different pressures, 80 Pa (high pressure) or 6.7 Pa (low pressure), were used. The chemical structure of the PECVD films was examined by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The dielectric constant ({epsilon} {sub r}) and dielectric loss (tan {delta}) of the films were investigated over a range of frequencies up to 1 MHz and the dielectric strength (breakdown voltage) (F {sub b}) was characterized by the current-voltage method. Spectroscopic ellipsometry was performed to determine the film thickness and refractive index. Good dielectric properties were exhibited, as PP-benzene films formed in the high pressure, DS region showed a F{sub b} of 610 V/{mu}m, an {epsilon} {sub r} of 3.07, and a tan {delta} of 7.0 x 10{sup -3} at 1 kHz. The PECVD processing pressure has a significant effect on final film structure and the film's physical density has a strong impact on dielectric breakdown strength. Also noted was that the residual oxygen content in the PP-benzene films significantly affected the frequency dependences of the dielectric constant and loss.

  18. The relationship between chemical structure and dielectric properties of plasma-enhanced chemical vapor deposited polymer thin films

    International Nuclear Information System (INIS)

    Jiang Hao; Hong Lianggou; Venkatasubramanian, N.; Grant, John T.; Eyink, Kurt; Wiacek, Kevin; Fries-Carr, Sandra; Enlow, Jesse; Bunning, Timothy J.

    2007-01-01

    Polymer dielectric films fabricated by plasma enhanced chemical vapor deposition (PECVD) have unique properties due to their dense crosslinked bulk structure. These spatially uniform films exhibit good adhesion to a variety of substrates, excellent chemical inertness, high thermal resistance, and are formed from an inexpensive, solvent-free, room temperature process. In this work, we studied the dielectric properties of plasma polymerized (PP) carbon-based polymer thin films prepared from two precursors, benzene and octafluorocyclobutane. Two different monomer feed locations, directly in the plasma zone or in the downstream region (DS) and two different pressures, 80 Pa (high pressure) or 6.7 Pa (low pressure), were used. The chemical structure of the PECVD films was examined by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The dielectric constant (ε r ) and dielectric loss (tan δ) of the films were investigated over a range of frequencies up to 1 MHz and the dielectric strength (breakdown voltage) (F b ) was characterized by the current-voltage method. Spectroscopic ellipsometry was performed to determine the film thickness and refractive index. Good dielectric properties were exhibited, as PP-benzene films formed in the high pressure, DS region showed a F b of 610 V/μm, an ε r of 3.07, and a tan δ of 7.0 x 10 -3 at 1 kHz. The PECVD processing pressure has a significant effect on final film structure and the film's physical density has a strong impact on dielectric breakdown strength. Also noted was that the residual oxygen content in the PP-benzene films significantly affected the frequency dependences of the dielectric constant and loss

  19. Growth of highly oriented carbon nanotubes by plasma-enhanced hot filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.P.; Xu, J.W.; Ren, Z.F.; Wang, J.H. [Materials Synthesis Laboratory, Departments of Physics and Chemistry, and Center for Advanced Photonic and Electronic Materials (CAPEM), State University of New York at Buffalo, Buffalo, New York 14260 (United States); Siegal, M.P.; Provencio, P.N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)

    1998-12-01

    Highly oriented, multiwalled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666 {degree}C. The carbon nanotubes range from 10 to 500 nm in diameter and 0.1 to 50 {mu}m in length depending on growth conditions. Acetylene is used as the carbon source for the growth of the carbon nanotubes and ammonia is used for dilution gas and catalysis. The plasma intensity, acetylene to ammonia gas ratio, and their flow rates, etc. affect the diameters and uniformity of the carbon nanotubes. {copyright} {ital 1998 American Institute of Physics.}

  20. Room-temperature plasma-enhanced chemical vapor deposition of SiOCH films using tetraethoxysilane

    International Nuclear Information System (INIS)

    Yamaoka, K.; Yoshizako, Y.; Kato, H.; Tsukiyama, D.; Terai, Y.; Fujiwara, Y.

    2006-01-01

    Carbon-doped silicon oxide (SiOCH) thin films were deposited by room-temperature plasma-enhanced chemical vapor deposition (PECVD) using tetraethoxysilane (TEOS). The deposition rate and composition of the films strongly depended on radio frequency (RF) power. The films deposited at low RF power contained more CH n groups. The SiOCH films showed high etch rate and low refractive index in proportion to the carbon composition. The deposition with low plasma density and low substrate temperature is effective for SiOCH growth by PECVD using TEOS

  1. PumpKin: A tool to find principal pathways in plasma chemical models

    Science.gov (United States)

    Markosyan, A. H.; Luque, A.; Gordillo-Vázquez, F. J.; Ebert, U.

    2014-10-01

    PumpKin is a software package to find all principal pathways, i.e. the dominant reaction sequences, in chemical reaction systems. Although many tools are available to integrate numerically arbitrarily complex chemical reaction systems, few tools exist in order to analyze the results and interpret them in relatively simple terms. In particular, due to the large disparity in the lifetimes of the interacting components, it is often useful to group reactions into pathways that recycle the fastest species. This allows a researcher to focus on the slow chemical dynamics, eliminating the shortest timescales. Based on the algorithm described by Lehmann (2004), PumpKin automates the process of finding such pathways, allowing the user to analyze complex kinetics and to understand the consumption and production of a certain species of interest. We designed PumpKin with an emphasis on plasma chemical systems but it can also be applied to atmospheric modeling and to industrial applications such as plasma medicine and plasma-assisted combustion.

  2. Topographic, optical and chemical properties of zinc particle coatings deposited by means of atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Wallenhorst, L.M.; Loewenthal, L.; Avramidis, G.; Gerhard, C.; Militz, H.; Ohms, G.; Viöl, W.

    2017-01-01

    Highlights: • Zn/ZnO mixed systems were deposited from elemental zinc by a cold plasma-spray process. • Oxidation was confirmed by XPS. • The coatings exhibited a strong absorption in the UV spectral range, thus being suitable as protective layers, e.g. on thermosensitive materials. - Abstract: In this research, topographic, optical and chemical properties of zinc oxide layers deposited by a cold plasma-spray process were measured. Here, zinc micro particles were fed to the afterglow of a plasma spark discharge whereas the substrates were placed in a quite cold zone of the effluent plasma jet. In this vein, almost closed layers were realised on different samples. As ascertained by laser scanning and atomic force microscopic measurements the particle size of the basic layer is in the nanometre scale. Additionally, larger particles and agglomerates were found on its top. The results indicate a partial plasma-induced diminishment of the initial particles, most probably due to melting or vaporisation. It is further shown that the plasma gives rise to an increased oxidation of such particles as confirmed by X-ray photoelectron spectroscopy. Quantitative analysis of the resulting mixed layer was performed. It is shown that the deposited layers consist of zinc oxide and elemental zinc in approximately equal shares. In addition, the layer's band gap energy was determined by spectroscopic analysis. Here, considerable UV blocking properties of the deposited layers were observed. Possible underlying effects as well as potential applications are presented.

  3. Topographic, optical and chemical properties of zinc particle coatings deposited by means of atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Wallenhorst, L.M., E-mail: lena.wallenhorst@hawk-hhg.de [University of Applied Sciences and Arts, Laboratory of Laser and Plasma Technologies, Von-Ossietzky-Str. 99, 37085 Göttingen (Germany); Loewenthal, L.; Avramidis, G. [University of Applied Sciences and Arts, Laboratory of Laser and Plasma Technologies, Von-Ossietzky-Str. 99, 37085 Göttingen (Germany); Gerhard, C. [University of Applied Sciences and Arts, Laboratory of Laser and Plasma Technologies, Von-Ossietzky-Str. 99, 37085 Göttingen (Germany); Fraunhofer Institute for Surface Engineering and Thin Films, Application Center for Plasma and Photonics, Von-Ossietzky-Str. 100, 37085 Göttingen (Germany); Militz, H. [Wood Biology and Wood Products, Burckhardt Institute, Georg-August-University Göttingen, Büsgenweg 4, 37077 Göttingen (Germany); Ohms, G. [University of Applied Sciences and Arts, Laboratory of Laser and Plasma Technologies, Von-Ossietzky-Str. 99, 37085 Göttingen (Germany); Viöl, W. [University of Applied Sciences and Arts, Laboratory of Laser and Plasma Technologies, Von-Ossietzky-Str. 99, 37085 Göttingen (Germany); Fraunhofer Institute for Surface Engineering and Thin Films, Application Center for Plasma and Photonics, Von-Ossietzky-Str. 100, 37085 Göttingen (Germany)

    2017-07-15

    Highlights: • Zn/ZnO mixed systems were deposited from elemental zinc by a cold plasma-spray process. • Oxidation was confirmed by XPS. • The coatings exhibited a strong absorption in the UV spectral range, thus being suitable as protective layers, e.g. on thermosensitive materials. - Abstract: In this research, topographic, optical and chemical properties of zinc oxide layers deposited by a cold plasma-spray process were measured. Here, zinc micro particles were fed to the afterglow of a plasma spark discharge whereas the substrates were placed in a quite cold zone of the effluent plasma jet. In this vein, almost closed layers were realised on different samples. As ascertained by laser scanning and atomic force microscopic measurements the particle size of the basic layer is in the nanometre scale. Additionally, larger particles and agglomerates were found on its top. The results indicate a partial plasma-induced diminishment of the initial particles, most probably due to melting or vaporisation. It is further shown that the plasma gives rise to an increased oxidation of such particles as confirmed by X-ray photoelectron spectroscopy. Quantitative analysis of the resulting mixed layer was performed. It is shown that the deposited layers consist of zinc oxide and elemental zinc in approximately equal shares. In addition, the layer's band gap energy was determined by spectroscopic analysis. Here, considerable UV blocking properties of the deposited layers were observed. Possible underlying effects as well as potential applications are presented.

  4. Improving plasma resistance and lowering roughness in an ArF photoresist by adding a chemical reaction inhibitor

    International Nuclear Information System (INIS)

    Jinnai, Butsurin; Uesugi, Takuji; Koyama, Koji; Samukawa, Seiji; Kato, Keisuke; Yasuda, Atsushi; Maeda, Shinichi; Momose, Hikaru

    2010-01-01

    Major challenges associated with 193 nm lithography using an ArF photoresist are low plasma resistance and roughness formation in the ArF photoresist during plasma processes. We have previously found decisive factors affecting the plasma resistance and roughness formation in an ArF photoresist: plasma resistance is determined by UV/VUV radiation, and roughness formation is dominated by chemical reactions. In this study, based on our findings on the interaction between plasma radiation species and ArF photoresist polymers, we proposed an ArF photoresist with a chemical reaction inhibitor, which can trap reactive species from the plasma, and characterized the performances of the resultant ArF photoresist through neutral beam experiments. Hindered amine light stabilizers, i.e. 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (HO-TEMPO), were used as the chemical reaction inhibitor. Etching rates of the ArF photoresist films were not dependent on the HO-TEMPO content in the irradiations without chemical reactions or under UV/VUV radiation. However, in the irradiation with chemical reactions, the etching rates of the ArF photoresist films decreased as the HO-TEMPO content increased. In addition, the surface roughness decreased with the increase in the additive amount of chemical reaction inhibitor. According to FTIR analysis, a chemical reaction inhibitor can inhibit the chemical reactions in ArF photoresist films through plasma radicals. These results indicate that a chemical reaction inhibitor is effective against chemical reactions, resulting in improved plasma resistance and less roughness in an ArF photoresist. These results also support our suggested mechanism of plasma resistance and roughness formation in an ArF photoresist.

  5. Informing the Human Plasma Protein Binding of Environmental Chemicals by Machine Learning in the Pharmaceutical Space: Applicability Domain and Limits of Predictability

    Science.gov (United States)

    The free fraction of a xenobiotic in plasma (Fub) is an important determinant of chemical adsorption, distribution, metabolism, elimination, and toxicity, yet experimental plasma protein binding data is scarce for environmentally relevant chemicals. The presented work explores th...

  6. One-step microwave plasma enhanced chemical vapor deposition (MW-PECVD) for transparent superhydrophobic surface

    Science.gov (United States)

    Thongrom, Sukrit; Tirawanichakul, Yutthana; Munsit, Nantakan; Deangngam, Chalongrat

    2018-02-01

    We demonstrate a rapid and environmental friendly fabrication technique to produce optically clear superhydrophobic surfaces using poly (dimethylsiloxane) (PDMS) as a sole coating material. The inert PDMS chain is transformed into a 3-D irregular solid network through microwave plasma enhanced chemical vapor deposition (MW-PECVD) process. Thanks to high electron density in the microwave-activated plasma, coating can be done in just a single step with rapid deposition rate, typically much shorter than 10 s. Deposited layers show excellent superhydrophobic properties with water contact angles of ∼170° and roll-off angles as small as ∼3°. The plasma-deposited films can be ultrathin with thicknesses under 400 nm, greatly diminishing the optical loss. Moreover, with appropriate coating conditions, the coating layer can even enhance the transmission over the entire visible spectrum due to a partial anti-reflection effect.

  7. Modelling chemical reactions in dc plasma inside oxygen bubbles in water

    International Nuclear Information System (INIS)

    Takeuchi, N; Ishii, Y; Yasuoka, K

    2012-01-01

    Plasmas generated inside oxygen bubbles in water have been developed for water purification. Zero-dimensional numerical simulations were used to investigate the chemical reactions in plasmas driven by dc voltage. The numerical and experimental results of the concentrations of hydrogen peroxide and ozone in the solution were compared with a discharge current between 1 and 7 mA. Upon increasing the water vapour concentration inside bubbles, we saw from the numerical results that the concentration of hydrogen peroxide increased with discharge current, whereas the concentration of ozone decreased. This finding agreed with the experimental results. With an increase in the discharge current, the heat flux from the plasma to the solution increased, and a large amount of water was probably vaporized into the bubbles.

  8. Modelling chemical reactions in dc plasma inside oxygen bubbles in water

    Science.gov (United States)

    Takeuchi, N.; Ishii, Y.; Yasuoka, K.

    2012-02-01

    Plasmas generated inside oxygen bubbles in water have been developed for water purification. Zero-dimensional numerical simulations were used to investigate the chemical reactions in plasmas driven by dc voltage. The numerical and experimental results of the concentrations of hydrogen peroxide and ozone in the solution were compared with a discharge current between 1 and 7 mA. Upon increasing the water vapour concentration inside bubbles, we saw from the numerical results that the concentration of hydrogen peroxide increased with discharge current, whereas the concentration of ozone decreased. This finding agreed with the experimental results. With an increase in the discharge current, the heat flux from the plasma to the solution increased, and a large amount of water was probably vaporized into the bubbles.

  9. Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures.

    Science.gov (United States)

    Koroglu, Batikan; Mehl, Marco; Armstrong, Michael R; Crowhurst, Jonathan C; Weisz, David G; Zaug, Joseph M; Dai, Zurong; Radousky, Harry B; Chernov, Alex; Ramon, Erick; Stavrou, Elissaios; Knight, Kim; Fabris, Andrea L; Cappelli, Mark A; Rose, Timothy P

    2017-09-01

    We present the development of a steady state plasma flow reactor to investigate gas phase physical and chemical processes that occur at high temperature (1000 flow injector). We have modeled the system using computational fluid dynamics simulations that are bounded by measured temperatures. In situ line-of-sight optical emission and absorption spectroscopy have been used to determine the structures and concentrations of molecules formed during rapid cooling of reactants after they pass through the plasma. Emission spectroscopy also enables us to determine the temperatures at which these dynamic processes occur. A sample collection probe inserted from the open end of the reactor is used to collect condensed materials and analyze them ex situ using electron microscopy. The preliminary results of two separate investigations involving the condensation of metal oxides and chemical kinetics of high-temperature gas reactions are discussed.

  10. The kinetics of nonequilibrium chain plasma-chemical oxidation in heterogeneous media

    International Nuclear Information System (INIS)

    Deminskii, M.A.; Potapkin, B.V.; Rusanov, V.D.

    1994-01-01

    The kinetics of oxidation of low-impurity components in air mixtures under heterogeneous conditions was studied. The principal kinetic features of the process were determined on the basis of theoretical analysis of plasma-chemical oxidation in heterogeneous media. The analysis also showed that low concentrations of impurities in liquid aerosol particles can be efficiently oxidized via a chain process induced by reactive species formed in the gas

  11. Chemically different non-thermal plasmas target distinct cell death pathways

    Czech Academy of Sciences Publication Activity Database

    Lunov, Oleg; Zablotskyy, Vitaliy A.; Churpita, Olexandr; Lunova, M.; Jirsa, M.; Dejneka, Alexandr; Kubinová, Šárka

    2017-01-01

    Roč. 7, č. 1 (2017), s. 1-17, č. článku 600. ISSN 2045-2322 Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:68378271 Keywords : chemically different * non-thermal plasmas * target distinct cell death pathways Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 4.259, year: 2016

  12. Dry-plasma-free chemical etch technique for variability reduction in multi-patterning (Conference Presentation)

    Science.gov (United States)

    Kal, Subhadeep; Mohanty, Nihar; Farrell, Richard A.; Franke, Elliott; Raley, Angelique; Thibaut, Sophie; Pereira, Cheryl; Pillai, Karthik; Ko, Akiteru; Mosden, Aelan; Biolsi, Peter

    2017-04-01

    Scaling beyond the 7nm technology node demands significant control over the variability down to a few angstroms, in order to achieve reasonable yield. For example, to meet the current scaling targets it is highly desirable to achieve sub 30nm pitch line/space features at back-end of the line (BEOL) or front end of line (FEOL); uniform and precise contact/hole patterning at middle of line (MOL). One of the quintessential requirements for such precise and possibly self-aligned patterning strategies is superior etch selectivity between the target films while other masks/films are exposed. The need to achieve high etch selectivity becomes more evident for unit process development at MOL and BEOL, as a result of low density films choices (compared to FEOL film choices) due to lower temperature budget. Low etch selectivity with conventional plasma and wet chemical etch techniques, causes significant gouging (un-intended etching of etch stop layer, as shown in Fig 1), high line edge roughness (LER)/line width roughness (LWR), non-uniformity, etc. In certain circumstances this may lead to added downstream process stochastics. Furthermore, conventional plasma etches may also have the added disadvantage of plasma VUV damage and corner rounding (Fig. 1). Finally, the above mentioned factors can potentially compromise edge placement error (EPE) and/or yield. Therefore a process flow enabled with extremely high selective etches inherent to film properties and/or etch chemistries is a significant advantage. To improve this etch selectivity for certain etch steps during a process flow, we have to implement alternate highly selective, plasma free techniques in conjunction with conventional plasma etches (Fig 2.). In this article, we will present our plasma free, chemical gas phase etch technique using chemistries that have high selectivity towards a spectrum of films owing to the reaction mechanism ( as shown Fig 1). Gas phase etches also help eliminate plasma damage to the

  13. Decontamination of chemical and biological warfare (CBW) agents using an atmospheric pressure plasma jet (APPJ)

    International Nuclear Information System (INIS)

    Herrmann, H.W.; Henins, I.; Park, J.; Selwyn, G.S.

    1999-01-01

    The atmospheric pressure plasma jet (APPJ) [A. Schuetze et al., IEEE Trans. Plasma Sci. 26, 1685 (1998)] is a nonthermal, high pressure, uniform glow plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g., He/O 2 /H 2 O), which flows between an outer, grounded, cylindrical electrode and an inner, coaxial electrode powered at 13.56 MHz rf. While passing through the plasma, the feedgas becomes excited, dissociated or ionized by electron impact. Once the gas exits the discharge volume, ions and electrons are rapidly lost by recombination, but the fast-flowing effluent still contains neutral metastable species (e.g., O 2 * , He * ) and radicals (e.g., O, OH). This reactive effluent has been shown to be an effective neutralizer of surrogates for anthrax spores and mustard blister agent. Unlike conventional wet decontamination methods, the plasma effluent does not cause corrosion and it does not destroy wiring, electronics, or most plastics, making it highly suitable for decontamination of sensitive equipment and interior spaces. Furthermore, the reactive species in the effluent rapidly degrade into harmless products leaving no lingering residue or harmful by-products. copyright 1999 American Institute of Physics

  14. Decontamination of chemical and biological warfare (CBW) agents using an atmospheric pressure plasma jet (APPJ)

    Science.gov (United States)

    Herrmann, H. W.; Henins, I.; Park, J.; Selwyn, G. S.

    1999-05-01

    The atmospheric pressure plasma jet (APPJ) [A. Schütze et al., IEEE Trans. Plasma Sci. 26, 1685 (1998)] is a nonthermal, high pressure, uniform glow plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g., He/O2/H2O), which flows between an outer, grounded, cylindrical electrode and an inner, coaxial electrode powered at 13.56 MHz rf. While passing through the plasma, the feedgas becomes excited, dissociated or ionized by electron impact. Once the gas exits the discharge volume, ions and electrons are rapidly lost by recombination, but the fast-flowing effluent still contains neutral metastable species (e.g., O2*, He*) and radicals (e.g., O, OH). This reactive effluent has been shown to be an effective neutralizer of surrogates for anthrax spores and mustard blister agent. Unlike conventional wet decontamination methods, the plasma effluent does not cause corrosion and it does not destroy wiring, electronics, or most plastics, making it highly suitable for decontamination of sensitive equipment and interior spaces. Furthermore, the reactive species in the effluent rapidly degrade into harmless products leaving no lingering residue or harmful by-products.

  15. Topographic, optical and chemical properties of zinc particle coatings deposited by means of atmospheric pressure plasma

    Science.gov (United States)

    Wallenhorst, L. M.; Loewenthal, L.; Avramidis, G.; Gerhard, C.; Militz, H.; Ohms, G.; Viöl, W.

    2017-07-01

    In this research, topographic, optical and chemical properties of zinc oxide layers deposited by a cold plasma-spray process were measured. Here, zinc micro particles were fed to the afterglow of a plasma spark discharge whereas the substrates were placed in a quite cold zone of the effluent plasma jet. In this vein, almost closed layers were realised on different samples. As ascertained by laser scanning and atomic force microscopic measurements the particle size of the basic layer is in the nanometre scale. Additionally, larger particles and agglomerates were found on its top. The results indicate a partial plasma-induced diminishment of the initial particles, most probably due to melting or vaporisation. It is further shown that the plasma gives rise to an increased oxidation of such particles as confirmed by X-ray photoelectron spectroscopy. Quantitative analysis of the resulting mixed layer was performed. It is shown that the deposited layers consist of zinc oxide and elemental zinc in approximately equal shares. In addition, the layer's band gap energy was determined by spectroscopic analysis. Here, considerable UV blocking properties of the deposited layers were observed. Possible underlying effects as well as potential applications are presented.

  16. Sensing signatures mediated by chemical structure of molecular solids in laser-induced plasmas.

    Science.gov (United States)

    Serrano, Jorge; Moros, Javier; Laserna, J Javier

    2015-03-03

    Laser ablation of organic compounds has been investigated for almost 30 years now, either in the framework of pulse laser deposition for the assembling of new materials or in the context of chemical sensing. Various monitoring techniques such as atomic and molecular fluorescence, time-of-flight mass spectrometry, and optical emission spectroscopy have been used for plasma diagnostics in an attempt to understand the spectral signature and potential origin of gas-phase ions and fragments from organic plasmas. Photochemical and photophysical processes occurring within these systems are generally much more complex than those suggested by observation of optical emission features. Together with laser ablation parameters, the structural and chemical-physical properties of molecules seem to be closely tied to the observed phenomena. The present manuscript, for the first time, discusses the role of molecular structure in the optical emission of organic plasmas. Factors altering the electronic distribution within the organic molecule have been found to have a direct impact on its ensuing optical emissions. The electron structure of an organic molecule, resulting from the presence, nature, and position of its atoms, governs the breakage of the molecule and, as a result, determines the extent of atomization and fragmentation that has proved to directly impact the emissions of CN radicals and C2 dimers. Particular properties of the molecule respond more positively depending on the laser irradiation wavelength, thereby redirecting the ablation process through photochemical or photothermal decomposition pathways. It is of paramount significance for chemical identification purposes how, despite the large energy stored and dissipated by the plasma and the considerable number of transient species formed, the emissions observed never lose sight of the original molecule.

  17. Sterilization and Decontamination of Surfaces Contaminated With Biological and Chemical Warfare Agents Using Atmospheric Pressure Plasma Discharges

    National Research Council Canada - National Science Library

    Garate, Eusebio

    1999-01-01

    ... based on the application of an atmospheric pressure plasma. We used both a DC corona and dielectric barrier discharge for the sterilization tests which were conducted on a variety of substrates including metals and chemically resistant fabrics...

  18. Chemical Changes in Nonthermal Plasma-Treated N-Acetylcysteine (NAC) Solution and Their Contribution to Bacterial Inactivation.

    Science.gov (United States)

    Ercan, Utku K; Smith, Josh; Ji, Hai-Feng; Brooks, Ari D; Joshi, Suresh G

    2016-02-02

    In continuation of our previous reports on the broad-spectrum antimicrobial activity of atmospheric non-thermal dielectric barrier discharge (DBD) plasma treated N-Acetylcysteine (NAC) solution against planktonic and biofilm forms of different multidrug resistant microorganisms, we present here the chemical changes that mediate inactivation of Escherichia coli. In this study, the mechanism and products of the chemical reactions in plasma-treated NAC solution are shown. UV-visible spectrometry, FT-IR, NMR, and colorimetric assays were utilized for chemical characterization of plasma treated NAC solution. The characterization results were correlated with the antimicrobial assays using determined chemical species in solution in order to confirm the major species that are responsible for antimicrobial inactivation. Our results have revealed that plasma treatment of NAC solution creates predominantly reactive nitrogen species versus reactive oxygen species, and the generated peroxynitrite is responsible for significant bacterial inactivation.

  19. A quantitative assay of cortisol in human plasma by high performance liquid chromatography using a selective chemically bonded stationary phase

    NARCIS (Netherlands)

    van den Berg, J.H.M.; Mol, C.R.; Deelder, R.S.; Thijssen, J.H.H.

    1977-01-01

    The extraction and subsequent liquid chromatographic analysis of human plasma samples for cortisol is described. Extraction and chromatography are optimized, resulting in a recovery for cortisol of 96% and a detection limit of 1 microgram cortisol in 100 ml plasma. The application of two chemically

  20. Synthesis of electro-active manganese oxide thin films by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, Anna R. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States); Rajagopalan, Ramakrishnan [Department of Engineering, The Pennsylvania State University, Dubois, PA 15801 (United States); Materials Research Institute, The Pennsylvania State University, University Park, PA 16802 (United States); Carter, Joshua D. [Energetics Research Division, Naval Air Warfare Center Weapons Division, China Lake, CA 93555 (United States)

    2014-04-01

    The good stability, cyclability and high specific capacitance of manganese oxide (MnO{sub x}) has recently promoted a growing interest in utilizing MnO{sub x} in asymmetric supercapacitor electrodes. Several literature reports have indicated that thin film geometries of MnO{sub x} provide specific capacitances that are much higher than bulk MnO{sub x} powders. Plasma enhanced chemical vapor deposition (PECVD) is a versatile technique for the production of metal oxide thin films with high purity and controllable thickness. In this work, MnO{sub x} thin films deposited by PECVD from a methylcyclopentadienyl manganese tricarbonyl precursor are presented and the effect of processing conditions on the quality of MnO{sub x} films is described. The film purity and oxidation state of the MnO{sub x} films were studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Preliminary electrochemical testing of MnO{sub x} films deposited on carbon fiber electrodes in aqueous electrolytes indicates that the PECVD synthesized films are electrochemically active. - Highlights: • Plasma enhanced chemical vapor deposition of manganese oxide thin films. • Higher plasma power and chamber pressure increase deposition rate. • Manganese oxide thin films are electrochemically active. • Best electrochemical performance observed for pure film with low stress • Lower capacitance observed at higher scan rates despite thin film geometry.

  1. Modeling of Sheath Ion-Molecule Reactions in Plasma Enhanced Chemical Vapor Deposition of Carbon Nanotubes

    Science.gov (United States)

    Hash, David B.; Govindan, T. R.; Meyyappan, M.

    2004-01-01

    In many plasma simulations, ion-molecule reactions are modeled using ion energy independent reaction rate coefficients that are taken from low temperature selected-ion flow tube experiments. Only exothermic or nearly thermoneutral reactions are considered. This is appropriate for plasma applications such as high-density plasma sources in which sheaths are collisionless and ion temperatures 111 the bulk p!asma do not deviate significantly from the gas temperature. However, for applications at high pressure and large sheath voltages, this assumption does not hold as the sheaths are collisional and ions gain significant energy in the sheaths from Joule heating. Ion temperatures and thus reaction rates vary significantly across the discharge, and endothermic reactions become important in the sheaths. One such application is plasma enhanced chemical vapor deposition of carbon nanotubes in which dc discharges are struck at pressures between 1-20 Torr with applied voltages in the range of 500-700 V. The present work investigates The importance of the inclusion of ion energy dependent ion-molecule reaction rates and the role of collision induced dissociation in generating radicals from the feedstock used in carbon nanotube growth.

  2. Contact glow discharge electrolysis: its origin, plasma diagnostics and non-faradaic chemical effects

    International Nuclear Information System (INIS)

    Sen Gupta, Susanta K

    2015-01-01

    Contact glow discharge electrolysis (CGDE) also termed plasma electrolysis is a novel electrolysis where a stable sheath of light emitting plasma develops around an electrode immersed well inside a relatively high-conductivity liquid electrolyte during normal electrolysis (NE) at several hundred volts. The phenomenon may develop in dc-, pulsed dc-, ac- as well as RF-driven electrolyses. The chemical effects of CGDE are remarkably non-faradaic in respect to the nature of the products as well as their yields. The article traces comprehensively the progress made in studies of CGDE in aqueous and non-aqueous solutions since 1844 and reviews the developments in the understanding of its origin, light emission, plasma state and non-faradaic effects leading to the elucidation of detailed mechanism of the origin of CGDE on the basis of the onset of hydrodynamic instabilities in local vaporization of the solvent near the working electrode during NE, and that of highly non-faradaic effects of CGDE based on a model of two reaction zones located within the electrode plasma and at the plasma–liquid interface producing solvent derived radicals at high local concentrations. Keeping in view the recent surge of interest in varied applications of CGDE, the article is appended with highlights of these applications across synthetic chemistry, waste water treatment, electrosurgical devices, nanoparticle fabrications, surface engineering and micro-machining. (topical review)

  3. One-step synthesis of chlorinated graphene by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Liwei; Zhang, Hui; Zhang, Pingping; Sun, Xuhui, E-mail: xhsun@suda.edu.cn

    2015-08-30

    Highlights: • We developed a simple approach to synthesize the single layer chlorinated graphene. • CuCl{sub 2} on Cu surface is used as Cl source under the plasma treatment. • The formation of covalent C−Cl bond has been investigated by Raman and XPS. • Raman results indicate the p-type doping effect of chlorination. - Abstract: We developed an approach to synthesize the chlorinated single layer graphene (Cl-G) by one-step plasma enhanced chemical vapor deposition. Copper foil was simply treated with hydrochloric acid and then CuCl{sub 2} formed on the surface was used as Cl source under the assistance of plasma treatment. Compared with other two-step methods by post plasma/photochemical treatment of CVD-grown single layer graphene (SLG), one-step Cl-G synthesis approach is quite straightforward and effective. X-ray photoelectron spectroscopy (XPS) revealed that ∼2.45 atom% Cl remained in SLG. Compared with the pristine SLG, the obvious blue shifts of G band and 2D band along with the appearance of D’ band and D + G band in the Raman spectra indicate p-type doping of Cl-G.

  4. Plasma-chemical simulation of negative corona near the inception voltage

    Science.gov (United States)

    Pontiga, Francisco; Duran-Olivencia, Francisco J.; Castellanos, Antonio

    2013-09-01

    The spatiotemporal development of Trichel pulses in oxygen between a spherical electrode and a grounded plane has been simulated using a fluid approximation that incorporates the plasma chemistry of the electrical discharge. Elementary plasma processes, such as ionization, electron attachment, electron detachment, recombination between ions and chemical reactions between neutral species, are all included in a chemical model consisting of 55 reactions between 8 different species (electrons, O2+,O2-,O3-,O-, O2, O, O3). Secondary emission at the cathode by the impact of positive ions and photons is also considered. The spatial distribution of species is computed in three dimensions (2D-axysimmetrical) by solving Poisson's equation for the electric field and the continuity equations for the species, with the inclusion of the chemical gain/loss rate due to the particle interaction. The results of the simulation reveal the interplay between the different negative ions during the development of every Trichel pulse, and the rate of production of atomic oxygen and ozone by the corona discharge. This work was supported by the Consejeria de Innovacion, Ciencia y Empresa (Junta de Andalucia) and by the Ministerio de Ciencia e Innovacion, Spain, within the European Regional Development Fund contracts FQM-4983 and FIS2011-25161.

  5. Mathematical modeling of quartz particle melting process in plasma-chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Volokitin, Oleg, E-mail: volokitin-oleg@mail.ru; Volokitin, Gennady, E-mail: vgg-tomsk@mail.ru; Skripnikova, Nelli, E-mail: nks2003@mai.ru; Shekhovtsov, Valentin, E-mail: shehovcov2010@yandex.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Vlasov, Viktor, E-mail: rector@tsuab.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Ave., 634050, Tomsk (Russian Federation)

    2016-01-15

    Among silica-based materials vitreous silica has a special place. The paper presents the melting process of a quartz particle under conditions of low-temperature plasma. A mathematical model is designed for stages of melting in the experimental plasma-chemical reactor. As calculation data show, quartz particles having the radius of 0.21≤ r{sub p} ≤0.64 mm completely melt at W = 0.65 l/s particle feed rate depending on the Nusselt number, while 0.14≤ r{sub p} ≤0.44 mm particles melt at W = 1.4 l/s. Calculation data showed that 2 mm and 0.4 mm quartz particles completely melted during and 0.1 s respectively. Thus, phase transformations occurred in silicon dioxide play the important part in its heating up to the melting temperature.

  6. Controlled density of vertically aligned carbon nanotubes in a triode plasma chemical vapor deposition system

    International Nuclear Information System (INIS)

    Lim, Sung Hoon; Park, Kyu Chang; Moon, Jong Hyun; Yoon, Hyun Sik; Pribat, Didier; Bonnassieux, Yvan; Jang, Jin

    2006-01-01

    We report on the growth mechanism and density control of vertically aligned carbon nanotubes using a triode plasma enhanced chemical vapor deposition system. The deposition reactor was designed in order to allow the intermediate mesh electrode to be biased independently from the ground and power electrodes. The CNTs grown with a mesh bias of + 300 V show a density of ∼ 1.5 μm -2 and a height of ∼ 5 μm. However, CNTs do not grow when the mesh electrode is biased to - 300 V. The growth of CNTs can be controlled by the mesh electrode bias which in turn controls the plasma density and ion flux on the sample

  7. Plasma Assisted Chemical Vapour Deposition – Technological Design Of Functional Coatings

    Directory of Open Access Journals (Sweden)

    Januś M.

    2015-06-01

    Full Text Available Plasma Assisted Chemical Vapour Deposition (PA CVD method allows to deposit of homogeneous, well-adhesive coatings at lower temperature on different substrates. Plasmochemical treatment significantly impacts on physicochemical parameters of modified surfaces. In this study we present the overview of the possibilities of plasma processes for the deposition of diamond-like carbon coatings doped Si and/or N atoms on the Ti Grade2, aluminum-zinc alloy and polyetherketone substrate. Depending on the type of modified substrate had improved the corrosion properties including biocompatibility of titanium surface, increase of surface hardness with deposition of good adhesion and fine-grained coatings (in the case of Al-Zn alloy and improving of the wear resistance (in the case of PEEK substrate.

  8. Effect of electronegative additives on physical properties and chemical activity of gas discharge plasma

    Science.gov (United States)

    Kuznetsov, D. L.; Filatov, I. E.; Uvarin, V. V.

    2018-01-01

    Effect of electronegative additives (oxygen O2, sulfur dioxide SO2, carbon disulfide CS2, and carbon tetrachloride CCl4) on physical properties and chemical activity of plasma formed by pulsed corona discharge and by non-self-sustained discharge supported by pulsed electron beam in atmospheric pressure gas mixtures was investigated. It is shown that a decrease in discharge current depends on a sort of the additive and on its concentration. The reason is the difference in rate constants of electron attachment processes for the above molecules. In experiments on volatile organic compounds (VOCs) conversion in air by streamer corona it is obtained that an addition of CCl4 both decreases the discharge current amplitude and increases the VOCs conversion degree. An installation for investigation of electron attachment processes and for study of toxic impurities conversion in plasma formed by non-self-sustained discharge initiated by pulsed nanosecond electron beam is created.

  9. Polycrystalline AlN films with preferential orientation by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Sanchez, G.; Wu, A.; Tristant, P.; Tixier, C.; Soulestin, B.; Desmaison, J.; Bologna Alles, A.

    2008-01-01

    AlN thin films for acoustic wave devices were prepared by Microwave Plasma Enhanced Chemical Vapor Deposition under different process conditions, employing Si (100) and Pt (111)/SiO 2 /Si (100) substrates. The films were characterized by X-ray diffraction, Fourier transform infrared transmission spectroscopy, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. The values of the distance between the plasma and the tri-methyl-aluminum precursor injector, the radiofrequency bias potential, and the substrate temperature were central in the development of polycrystalline films. The choice of the chamber total pressure during deposition allowed for the development of two different crystallographic orientations, i.e., or . The film microstructures exhibited in general a column-like growth with rounded tops, an average grain size of about 40 nm, and a surface roughness lower than 20 nm under the best conditions

  10. Aqueous media treatment and decontamination of hazardous chemical and biological substances by contact plasma

    International Nuclear Information System (INIS)

    Pivovarov, A.; Kravchenko, A.; Kublanovsky, V.

    2009-01-01

    Usage of non-equilibrium contact plasma for processes of decontamination and neutralization in conditions of manifestation of chemical, biological and radiation terrorism takes on special significance due to portability of equipment and its mobility in places where toxic liquid media hazardous for people's health are located. Processes of decontamination of aqueous media, seminated with pathogenic microorganisms and viruses, treatment of water containing toxic heavy metals, cyanides, surface-active substances, and heavy radioactive elements, are investigated. Examples of activation processes in infected water and toxic aqueous solutions present convincing evidence of the way, how new quality technological approach for achievement of high enough degree of the said media treatment is used in each specific case. Among new properties of water activated as a result of action of non-equilibrium contact plasma, it is necessary to mention presence of cluster structure, confirmed by well-known spectral and physical-chemical methods, presence of peroxide compounds, active particles and radicals. Anti-microbial activity which is displayed under action of plasma in aqueous media (chemically pure water, drinking water, aqueous solutions of sodium chloride, potassium iodide, as well as other inorganic compounds) towards wide range of pathogenic and conventionally pathogenic microorganisms allows use them as reliable, accessible and low-cost preparations for increasing the degree of safety of food products. Combination of such processes with known methods of filtration and ultra-filtration gives an efficient and available complex capable of withstanding any threats, which may arise for population and living organisms. Present-day level of machine-building, electrical engineering, and electronics allows predict creation of industrial plasma installations, adapted to conditions of various terrorist threats, with minimized power consumption and optimized technological parameters

  11. Aqueous media treatment and decontamination of hazardous chemical and biological substances by contact plasma

    Energy Technology Data Exchange (ETDEWEB)

    Pivovarov, A; Kravchenko, A [Ukrainian State University of Chemical Engineering, Dnepropetrovsk (Ukraine); Kublanovsky, V [V. I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Science, Kiev (Ukraine)

    2009-07-01

    Usage of non-equilibrium contact plasma for processes of decontamination and neutralization in conditions of manifestation of chemical, biological and radiation terrorism takes on special significance due to portability of equipment and its mobility in places where toxic liquid media hazardous for people's health are located. Processes of decontamination of aqueous media, seminated with pathogenic microorganisms and viruses, treatment of water containing toxic heavy metals, cyanides, surface-active substances, and heavy radioactive elements, are investigated. Examples of activation processes in infected water and toxic aqueous solutions present convincing evidence of the way, how new quality technological approach for achievement of high enough degree of the said media treatment is used in each specific case. Among new properties of water activated as a result of action of non-equilibrium contact plasma, it is necessary to mention presence of cluster structure, confirmed by well-known spectral and physical-chemical methods, presence of peroxide compounds, active particles and radicals. Anti-microbial activity which is displayed under action of plasma in aqueous media (chemically pure water, drinking water, aqueous solutions of sodium chloride, potassium iodide, as well as other inorganic compounds) towards wide range of pathogenic and conventionally pathogenic microorganisms allows use them as reliable, accessible and low-cost preparations for increasing the degree of safety of food products. Combination of such processes with known methods of filtration and ultra-filtration gives an efficient and available complex capable of withstanding any threats, which may arise for population and living organisms. Present-day level of machine-building, electrical engineering, and electronics allows predict creation of industrial plasma installations, adapted to conditions of various terrorist threats, with minimized power consumption and optimized technological parameters

  12. Chemically reacting flow of a compressible thermally radiating two-component plasma

    International Nuclear Information System (INIS)

    Bestman, A.R.

    1990-12-01

    The paper studies the compressible flow of a hot two-component plasma in the presence of gravitation and chemical reaction in a vertical channel. For the optically thick gas approximation, closed form analytical solutions are possible. Asymptotic solutions are also obtained for the general differential approximation when the temperature of the two bounding walls are the same. In the general case the problem is reduced to the solution of standard nonlinear integral equations which can be tackled by iterative procedure. The results are discussed quantitatively. The problem may be applicable to the understanding of explosive hydrogen-burning model of solar flares. (author). 6 refs, 4 figs

  13. Carbon nanosheets by microwave plasma enhanced chemical vapor deposition in CH4-Ar system

    International Nuclear Information System (INIS)

    Wang Zhipeng; Shoji, Mao; Ogata, Hironori

    2011-01-01

    We employ a new gas mixture of CH 4 -Ar to fabricate carbon nanosheets by microwave plasma enhanced chemical vapor deposition at the growth temperature of less than 500 deg. C. The catalyst-free nanosheets possess flower-like structures with a large amount of sharp edges, which consist of a few layers of graphene sheets according to the observation by transmission electron microscopy. These high-quality carbon nanosheets demonstrated a faster electron transfer between the electrolyte and the nanosheet surface, due to their edge defects and graphene structures.

  14. An unstructured shock-fitting solver for hypersonic plasma flows in chemical non-equilibrium

    Science.gov (United States)

    Pepe, R.; Bonfiglioli, A.; D'Angola, A.; Colonna, G.; Paciorri, R.

    2015-11-01

    A CFD solver, using Residual Distribution Schemes on unstructured grids, has been extended to deal with inviscid chemical non-equilibrium flows. The conservative equations have been coupled with a kinetic model for argon plasma which includes the argon metastable state as independent species, taking into account electron-atom and atom-atom processes. Results in the case of an hypersonic flow around an infinite cylinder, obtained by using both shock-capturing and shock-fitting approaches, show higher accuracy of the shock-fitting approach.

  15. The structure and growth mechanism of Si nanoneedles prepared by plasma-enhanced chemical vapor deposition

    Czech Academy of Sciences Publication Activity Database

    Červenka, Jiří; Ledinský, Martin; Stuchlík, Jiří; Stuchlíková, The-Ha; Bakardjieva, Snejana; Hruška, Karel; Fejfar, Antonín; Kočka, Jan

    2010-01-01

    Roč. 21, č. 41 (2010), 415604/1-415604/7 ISSN 0957-4484 R&D Projects: GA MŠk(CZ) LC06040; GA AV ČR KAN400100701; GA MŠk LC510 EU Projects: European Commission(XE) 240826 - PolySiMode Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z40320502 Keywords : nanoneedles * nanowires * silicon * plasma * chemical vapor deposition * crystal structure * growth * phonon * SEM * Raman Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.644, year: 2010

  16. Drag force in strongly coupled, anisotropic plasma at finite chemical potential

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Somdeb; Haque, Najmul [Theory Division, Saha Institute of Nuclear Physics,1/AF Bidhannagar, Kolkata-700 064 (India)

    2014-12-30

    We employ methods of gauge/string duality to analyze the drag force on a heavy quark moving through a strongly coupled, anisotropic N=4,SU(N) super Yang-Mills plasma in the presence of a finite U(1) chemical potential. We present numerical results valid for any value of the anisotropy parameter and the U(1) charge density and arbitrary direction of the quark velocity with respect to the direction of anisotropy. In the small anisotropy limit we are also able to furnish analytical results.

  17. Relationship between deprotection and film thickness loss during plasma etching of positive tone chemically amplified resists

    International Nuclear Information System (INIS)

    Mahorowala, A.P.; Medeiros, D.R.

    2001-01-01

    Positive tone chemically amplified (CA) resists have demonstrated the sensitivity, contrast, and resolution necessary to print state-of-the-art subwavelength features using 248 nm and more recently 193 nm lithography. These materials are also being considered for printing sub-100 nm features with 157 nm and next-generation lithography technologies such as extreme ultraviolet and electron beam projection lithography. The basis for solubility differential and image formation in these resists is the acid catalyzed deprotection of labile protecting groups of an inherently base soluble polymer. The deprotection is effected by the photochemical generation of strong acid during the exposure process. Such acid-catalyzed deprotection reactions can also occur in unexposed resist areas when etched in a plasma. This can be due to UV exposure, high-energy ion bombardment, elevated substrate temperatures, or interaction of the resist surface with plasma species to form acidic moieties. Deprotection has been associated with resist mass loss and film shrinkage during plasma etching, leaving inadequate masking material for the entire etch step. In this article, we report the film thickness loss of several unexposed CA resists as a function of etch time in a variety of plasmas and correlate these data with film composition, monitored by Fourier transform infrared spectroscopy. These results are compared with theoretical predictions based on generally accepted deprotection mechanisms. Our findings indicate that the 'acidic' nature of certain plasmas such as Cl 2 /O 2 can result in deprotection in the resist film, even in the absence of a photoacid generator. Additionally, the data suggest that the nature of the resist polymer and, in turn, the identity of the deprotection products directly influence resist mass loss and etch rate linearity, both of which can be controlled by careful selection of resist materials

  18. Photon production in an expanding and chemically equilibrating gluon-enriched plasma

    International Nuclear Information System (INIS)

    Kaempfer, B.; Technische Univ. Dresden; Pavlenko, O.P.; AN Ukrainskoj SSR, Kiev

    1993-12-01

    Photon production in a longitudinally and transversely expanding gluon plasma with initially little quark admixture is considered. Chemical equilibration of quarks and gluons is followed by rate equations. The yields of hard photons with E ≥ 2 GeV are insensitive to chemical equilibration and depend mainly on the initial thermalized state. Medium-energy photons with E ∼ 1 GeV are more frequently produced in case of faster equilibration, despite of faster cooling. For an assumed fast equilibration we follow the evolution of matter through mixed and hadron phases. The transverse momentum kick, due to transverse expansion, of photons from hadron matter is shown to be reduced for an equation of state with reduced latent heat. The photon yield in the region E > 1 GeV from deconfined matter dominates for conditions, estimated to be achieved at RHIC, in case of a weakly first-order confinement transition. (orig.)

  19. Development of novel tungsten processing technologies for electro-chemical machining (ECM) of plasma facing components

    International Nuclear Information System (INIS)

    Holstein, Nils; Krauss, Wolfgang; Konys, Juergen

    2011-01-01

    Plasma facing components for fusion applications must exhibit long-term stability under extreme conditions, and therefore material imperfections cannot be tolerated due to a high risk of technical failures. To prevent or abolish defects in refractory metals components during the manufacturing process, some methods of electro-chemical machining as S-ECM and C-ECM were developed, enabling both the processing of smooth plain defect-free surfaces of different geometry and the removal of bulk material for the shaping of three-dimensional structures, also without cracks. It is discussed, that tungsten ablation with accurate electro-chemical molding is very sensitive to the kind of electric current, and therefore current investigations focused also on the effects of frequency profiles on the sharpness of edge rounding.

  20. A solid-state nuclear magnetic resonance study of post-plasma reactions in organosilicone microwave plasma-enhanced chemical vapor deposition (PECVD) coatings.

    Science.gov (United States)

    Hall, Colin J; Ponnusamy, Thirunavukkarasu; Murphy, Peter J; Lindberg, Mats; Antzutkin, Oleg N; Griesser, Hans J

    2014-06-11

    Plasma-polymerized organosilicone coatings can be used to impart abrasion resistance and barrier properties to plastic substrates such as polycarbonate. Coating rates suitable for industrial-scale deposition, up to 100 nm/s, can be achieved through the use of microwave plasma-enhanced chemical vapor deposition (PECVD), with optimal process vapors such as tetramethyldisiloxane (TMDSO) and oxygen. However, it has been found that under certain deposition conditions, such coatings are subject to post-plasma changes; crazing or cracking can occur anytime from days to months after deposition. To understand the cause of the crazing and its dependence on processing plasma parameters, the effects of post-plasma reactions on the chemical bonding structure of coatings deposited with varying TMDSO-to-O2 ratios was studied with (29)Si and (13)C solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) using both single-pulse and cross-polarization techniques. The coatings showed complex chemical compositions significantly altered from the parent monomer. (29)Si MAS NMR spectra revealed four main groups of resonance lines, which correspond to four siloxane moieties (i.e., mono (M), di (D), tri (T), and quaternary (Q)) and how they are bound to oxygen. Quantitative measurements showed that the ratio of TMDSO to oxygen could shift the chemical structure of the coating from 39% to 55% in Q-type bonds and from 28% to 16% for D-type bonds. Post-plasma reactions were found to produce changes in relative intensities of (29)Si resonance lines. The NMR data were complemented by Fourier transform infrared (FTIR) spectroscopy. Together, these techniques have shown that the bonding environment of Si is drastically altered by varying the TMDSO-to-O2 ratio during PECVD, and that post-plasma reactions increase the cross-link density of the silicon-oxygen network. It appears that Si-H and Si-OH chemical groups are the most susceptible to post-plasma reactions. Coatings produced at a

  1. Decontamination of Chemical/Biological Warfare (CBW) Agents Using an Atmospheric Pressure Plasma Jet (APPJ)

    Science.gov (United States)

    Herrmann, Hans W.

    1998-11-01

    The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure, uniform glow discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g. He/O_2/H_2O) which flows between an outer, grounded, cylindrical electrode and an inner, coaxial electrode powered at 13.56 MHz RF. While passing through the plasma, the feedgas becomes excited, dissociated or ionized by electron impact. Once the gas exits the discharge volume, ions and electrons are rapidly lost by recombination, but the fast-flowing effluent still contains metastables (e.g. O2*, He*) and radicals (e.g. O, OH). These reactive species have been shown to be effective neutralizers of surrogates for anthrax spores, mustard blister agent and VX nerve gas. Unlike conventional, wet decontamination methods, the plasma effluent does not cause corrosion of most surfaces and does not damage wiring, electronics, nor most plastics. This makes it highly suitable for decontamination of high value sensitive equipment such as is found in vehicle interiors (i.e. tanks, planes...) for which there is currently no good decontamination technique. Furthermore, the reactive species rapidly degrade into harmless products leaving no lingering residue or harmful byproducts. Physics of the APPJ will be discussed and results of surface decontamination experiments using simulant and actual CBW agents will be presented.

  2. Numerical simulation of Trichel pulses of negative DC corona discharge based on a plasma chemical model

    Science.gov (United States)

    Chen, Xiaoyue; Lan, Lei; Lu, Hailiang; Wang, Yu; Wen, Xishan; Du, Xinyu; He, Wangling

    2017-10-01

    A numerical simulation method of negative direct current (DC) corona discharge based on a plasma chemical model is presented, and a coaxial cylindrical gap is adopted. There were 15 particle species and 61 kinds of collision reactions electrons involved, and 22 kinds of reactions between ions are considered in plasma chemical reactions. Based on this method, continuous Trichel pulses are calculated on about a 100 us timescale, and microcosmic physicochemical process of negative DC corona discharge in three different periods is discussed. The obtained results show that the amplitude of Trichel pulses is between 1-2 mA, and that pulse interval is in the order of 10-5 s. The positive ions produced by avalanche ionization enhanced the electric field near the cathode at the beginning of the pulse, then disappeared from the surface of cathode. The electric field decreases and the pulse ceases to develop. The negative ions produced by attachment slowly move away from the cathode, and the electric field increases gradually until the next pulse begins to develop. The positive and negative ions with the highest density during the corona discharge process are O4+ and O3- , respectively.

  3. Difference in chemical reactions in bulk plasma and sheath regions during surface modification of graphene oxide film using capacitively coupled NH{sub 3} plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung-Youp; Kim, Chan; Kim, Hong Tak, E-mail: zam89blue@gmail.com [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2015-09-14

    Reduced graphene oxide (r-GO) films were obtained from capacitively coupled NH{sub 3} plasma treatment of spin-coated graphene oxide (GO) films at room temperature. Variations were evaluated according to the two plasma treatment regions: the bulk plasma region (R{sub bulk}) and the sheath region (R{sub sheath}). Reduction and nitridation of the GO films began as soon as the NH{sub 3} plasma was exposed to both regions. However, with the increase in treatment time, the reduction and nitridation reactions differed in each region. In the R{sub bulk}, NH{sub 3} plasma ions reacted chemically with oxygen functional groups on the GO films, which was highly effective for reduction and nitridation. While in the R{sub sheath}, physical reactions by ion bombardment were dominant because plasma ions were accelerated by the strong electrical field. The accelerated plasma ions reacted not only with the oxygen functional groups but also with the broken carbon chains, which caused the removal of the GO films by the formation of hydrocarbon gas species. These results showed that reduction and nitridation in the R{sub bulk} using capacitively coupled NH{sub 3} plasma were very effective for modifying the properties of r-GO films for application as transparent conductive films.

  4. Nitrogen Fixation by Gliding Arc Plasma: Better Insight by Chemical Kinetics Modelling.

    Science.gov (United States)

    Wang, Weizong; Patil, Bhaskar; Heijkers, Stjin; Hessel, Volker; Bogaerts, Annemie

    2017-05-22

    The conversion of atmospheric nitrogen into valuable compounds, that is, so-called nitrogen fixation, is gaining increased interest, owing to the essential role in the nitrogen cycle of the biosphere. Plasma technology, and more specifically gliding arc plasma, has great potential in this area, but little is known about the underlying mechanisms. Therefore, we developed a detailed chemical kinetics model for a pulsed-power gliding-arc reactor operating at atmospheric pressure for nitrogen oxide synthesis. Experiments are performed to validate the model and reasonable agreement is reached between the calculated and measured NO and NO 2 yields and the corresponding energy efficiency for NO x formation for different N 2 /O 2 ratios, indicating that the model can provide a realistic picture of the plasma chemistry. Therefore, we can use the model to investigate the reaction pathways for the formation and loss of NO x . The results indicate that vibrational excitation of N 2 in the gliding arc contributes significantly to activating the N 2 molecules, and leads to an energy efficient way of NO x production, compared to the thermal process. Based on the underlying chemistry, the model allows us to propose solutions on how to further improve the NO x formation by gliding arc technology. Although the energy efficiency of the gliding-arc-based nitrogen fixation process at the present stage is not comparable to the world-scale Haber-Bosch process, we believe our study helps us to come up with more realistic scenarios of entering a cutting-edge innovation in new business cases for the decentralised production of fertilisers for agriculture, in which low-temperature plasma technology might play an important role. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Plasma diagnostics and device properties of AlGaN/GaN HEMT passivated with SiN deposited by plasma-enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Romero, M F; Sanz, M M; Munoz, E [ISOM-Universidad Politecnica de Madrid (UPM). ETSIT, Madrid (Spain); Tanarro, I [Instituto de Estructura de la Materia, CSIC, Madrid (Spain); Jimenez, A, E-mail: itanarro@iem.cfmac.csic.e [Departamento Electronica, Escuela Politecnica Superior, Universidad de Alcala, Alcala de Henares, Madrid (Spain)

    2010-12-15

    In this work, silicon nitride thin films have been deposited by plasma enhanced chemical vapour deposition on both silicon samples and AlGaN/GaN high electron mobility transistors (HEMT) grown on sapphire substrates. Commercial parallel-plate RF plasma equipment has been used. During depositions, the dissociation rates of SiH{sub 4} and NH{sub 3} precursors and the formation of H{sub 2} and N{sub 2} have been analysed by mass spectrometry as a function of the NH{sub 3}/SiH{sub 4} flow ratio and the RF power applied to the plasma reactor. Afterwards, the properties of the films and the HEMT electrical characteristics have been studied. Plasma composition has been correlated with the SiN deposition rate, refractive index, H content and the final electric characteristics of the passivated transistors.

  6. Proton-sensing transistor systems for detecting ion leakage from plasma membranes under chemical stimuli.

    Science.gov (United States)

    Imaizumi, Yuki; Goda, Tatsuro; Schaffhauser, Daniel F; Okada, Jun-Ichi; Matsumoto, Akira; Miyahara, Yuji

    2017-03-01

    The membrane integrity of live cells is routinely evaluated for cytotoxicity induced by chemical or physical stimuli. Recent progress in bioengineering means that high-quality toxicity validation is required. Here, we report a pH-sensitive transistor system developed for the continuous monitoring of ion leakage from cell membranes upon challenge by toxic compounds. Temporal changes in pH were generated with high reproducibility via periodic flushing of HepG2 cells on a gate insulator of a proton-sensitive field-effect transistor with isotonic buffer solutions with/without NH 4 Cl. The pH transients at the point of NH 4 Cl addition/withdrawal originated from the free permeation of NH 3 across the semi-permeable plasma membranes, and the proton sponge effect produced by the ammonia equilibrium. Irreversible attenuation of the pH transient was observed when the cells were subjected to a membrane-toxic reagent. Experiments and simulations proved that the decrease in the pH transient was proportional to the area of the ion-permeable pores on the damaged plasma membranes. The pH signal was correlated with the degree of hemolysis produced by the model reagents. The pH assay was sensitive to the formation of molecularly sized pores that were otherwise not measurable via detection of the leakage of hemoglobin, because the hydrodynamic radius of hemoglobin was greater than 3.1nm in the hemolysis assay. The pH transient was not disturbed by inherent ion-transporter activity. The ISFET assay was applied to a wide variety of cell types. The system presented here is fast, sensitive, practical and scalable, and will be useful for validating cytotoxins and nanomaterials. The plasma membrane toxicity and hemolysis are widely and routinely evaluated in biomaterials science and biomedical engineering. Despite the recent development of a variety of methods/materials for efficient gene/drug delivery systems to the cytosol, the methodologies for safety validation remain unchanged in

  7. Simulated experiment for elimination of chemical and biological warfare agents by making use of microwave plasma torch

    International Nuclear Information System (INIS)

    Hong, Yong C.; Kim, Jeong H.; Uhm, Han S.

    2004-01-01

    The threat of chemical and biological warfare agents in a domestic terrorist attack and in military conflict is increasing worldwide. Elimination and decontamination of chemical and biological warfare (CBW) agents are immediately required after such an attack. Simulated experiment for elimination of CBW agents by making use of atmospheric-pressure microwave plasma torches is carried out. Elimination of biological warfare agents indicated by the vitrification or burnout of sewage sludge powders and decomposition of toluene gas as a chemical agent stimulant are presented. A detailed characterization for the elimination of the simulant chemicals using Fourier transform infrared and gas chromatography is also presented

  8. Simulated experiment for elimination of chemical and biological warfare agents by making use of microwave plasma torch

    Science.gov (United States)

    Hong, Yong C.; Kim, Jeong H.; Uhm, Han S.

    2004-02-01

    The threat of chemical and biological warfare agents in a domestic terrorist attack and in military conflict is increasing worldwide. Elimination and decontamination of chemical and biological warfare (CBW) agents are immediately required after such an attack. Simulated experiment for elimination of CBW agents by making use of atmospheric-pressure microwave plasma torches is carried out. Elimination of biological warfare agents indicated by the vitrification or burnout of sewage sludge powders and decomposition of toluene gas as a chemical agent stimulant are presented. A detailed characterization for the elimination of the simulant chemicals using Fourier transform infrared and gas chromatography is also presented.

  9. Plasma for electrification of chemical industry: a case study on CO2 reduction

    Science.gov (United States)

    van Rooij, G. J.; Akse, H. N.; Bongers, W. A.; van de Sanden, M. C. M.

    2018-01-01

    Significant growth of the share of (intermittent) renewable power in the chemical industry is imperative to meet increasingly stricter limits on CO2 exhaust that are being implemented within Europe. This paper aims to evaluate the potential of a plasma process that converts input CO2 into a pure stream of CO to aid in renewable energy penetration in this sector. A realistic process design is constructed to serve as a basis for an economical analysis. The manufacturing cost price of CO is estimated at 1.2 kUS ton-1 CO. A sensitivity analysis shows that separation is the dominant cost factor, so that improving conversion is currently more effective to lower the price than e.g. energy efficiency.

  10. Plasma chemical and electrical modelling of a negative DC corona in pure oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Soria, C [Departamento de Electronica y Electromagnetismo, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Pontiga, F [Departamento de FIsica Aplicada II, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain); Castellanos, A [Departamento de Electronica y Electromagnetismo, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Sevilla (Spain)

    2004-02-01

    A complex plasma chemical and electrical model of a negative stationary wire-to-cylinder corona discharge in pure oxygen is presented. The corona discharge is assumed to have axial and azimuthal symmetry. The experimental current-voltage characteristic is required as input data, but there are no other adjustable or empirical parameters. The experimental validation of the results of the model comes from its prediction of the ozone concentration. The role played by different reactions and species is analysed in detail using the results of the simulation. The effect of the gas temperature and of the decomposition of ozone at the electrodes is also investigated. The agreement between the model and the experiments is excellent when the effect of ozone decomposition at the electrodes is taken into account.

  11. Microwave plasma-enhanced chemical vapour deposition growth of carbon nanostructures

    Directory of Open Access Journals (Sweden)

    Shivan R. Singh

    2010-05-01

    Full Text Available The effect of various input parameters on the production of carbon nanostructures using a simple microwave plasma-enhanced chemical vapour deposition technique has been investigated. The technique utilises a conventional microwave oven as the microwave energy source. The developed apparatus is inexpensive and easy to install and is suitable for use as a carbon nanostructure source for potential laboratory-based research of the bulk properties of carbon nanostructures. A result of this investigation is the reproducibility of specific nanostructures with the variation of input parameters, such as carbon-containing precursor and support gas flow rate. It was shown that the yield and quality of the carbon products is directly controlled by input parameters. Transmission electron microscopy and scanning electron microscopy were used to analyse the carbon products; these were found to be amorphous, nanotubes and onion-like nanostructures.

  12. Low temperature metal free growth of graphene on insulating substrates by plasma assisted chemical vapor deposition

    Science.gov (United States)

    Muñoz, R.; Munuera, C.; Martínez, J. I.; Azpeitia, J.; Gómez-Aleixandre, C.; García-Hernández, M.

    2017-03-01

    Direct growth of graphene films on dielectric substrates (quartz and silica) is reported, by means of remote electron cyclotron resonance plasma assisted chemical vapor deposition r-(ECR-CVD) at low temperature (650 °C). Using a two step deposition process- nucleation and growth- by changing the partial pressure of the gas precursors at constant temperature, mostly monolayer continuous films, with grain sizes up to 500 nm are grown, exhibiting transmittance larger than 92% and sheet resistance as low as 900 Ω sq-1. The grain size and nucleation density of the resulting graphene sheets can be controlled varying the deposition time and pressure. In additon, first-principles DFT-based calculations have been carried out in order to rationalize the oxygen reduction in the quartz surface experimentally observed. This method is easily scalable and avoids damaging and expensive transfer steps of graphene films, improving compatibility with current fabrication technologies.

  13. High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition

    Science.gov (United States)

    Cui, Linfan; Chen, Jiangtao; Yang, Bingjun; Jiao, Tifeng

    2015-12-01

    Vertically, carbon nanotube (CNT) arrays were successfully fabricated on hexagon patterned Si substrates through radio frequency plasma-enhanced chemical vapor deposition using gas mixtures of acetylene (C2H2) and hydrogen (H2) with Fe/Al2O3 catalysts. The CNTs were found to be graphitized with multi-walled structures. Different H2/C2H2 gas flow rate ratio was used to investigate the effect on CNT growth, and the field emission properties were optimized. The CNT emitters exhibited excellent field emission performance (the turn-on and threshold fields were 2.1 and 2.4 V/μm, respectively). The largest emission current could reach 70 mA/cm2. The emission current was stable, and no obvious deterioration was observed during the long-term stability test of 50 h. The results were relevant for practical applications based on CNTs.

  14. Stress hysteresis and mechanical properties of plasma-enhanced chemical vapor deposited dielectric films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.; Kamarajugadda, Mallika; Bozeman, Steven P.; Stearns, Laura C.

    2004-02-01

    A comprehensive survey is described of the responses of three plasma-enhanced chemical vapor deposited dielectric film systems to thermal cycling and indentation contact. All three films—silicon oxide, silicon nitride, and silicon oxy-nitride—exhibited significant nonequilibrium permanent changes in film stress on thermal cycling or annealing. The linear relationship between stress and temperature changed after the films were annealed at 300 °C, representing a structural alteration in the film reflecting a change in coefficient of thermal expansion or biaxial modulus. A double-substrate method was used to deduce both thermoelastic properties before and after the anneal of selected films and the results were compared with the modulus deconvoluted from small-scale depth-sensing indentation experiments (nanoindentation). Rutherford backscattering spectrometry and hydrogen forward scattering were used to deduce the composition of the films and it was found that all the films contained significant amounts of hydrogen.

  15. Low-temperature synthesis of graphene on nickel foil by microwave plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kim, Y.; Song, W.; Lee, S. Y.; Jeon, C.; Jung, W.; Kim, M.; Park, C.-Y.

    2011-01-01

    Microwave plasma chemical vapor deposition (MPCVD) was employed to synthesize high quality centimeter scale graphene film at low temperatures. Monolayer graphene was obtained by varying the gas mixing ratio of hydrogen and methane to 80:1. Using advantages of MPCVD, the synthesis temperature was decreased from 750 deg. C down to 450 deg. C. Optical microscopy and Raman mapping images exhibited that a large area monolayer graphene was synthesized regardless of the temperatures. Since the overall transparency of 89% and low sheet resistances ranging from 590 to 1855 Ω/sq of graphene films were achieved at considerably low synthesis temperatures, MPCVD can be adopted in manufacturing future large-area electronic devices based on graphene film.

  16. Low-temperature synthesis of graphene on nickel foil by microwave plasma chemical vapor deposition

    Science.gov (United States)

    Kim, Y.; Song, W.; Lee, S. Y.; Jeon, C.; Jung, W.; Kim, M.; Park, C.-Y.

    2011-06-01

    Microwave plasma chemical vapor deposition (MPCVD) was employed to synthesize high quality centimeter scale graphene film at low temperatures. Monolayer graphene was obtained by varying the gas mixing ratio of hydrogen and methane to 80:1. Using advantages of MPCVD, the synthesis temperature was decreased from 750 °C down to 450 °C. Optical microscopy and Raman mapping images exhibited that a large area monolayer graphene was synthesized regardless of the temperatures. Since the overall transparency of 89% and low sheet resistances ranging from 590 to 1855 Ω/sq of graphene films were achieved at considerably low synthesis temperatures, MPCVD can be adopted in manufacturing future large-area electronic devices based on graphene film.

  17. Stress hysteresis during thermal cycling of plasma-enhanced chemical vapor deposited silicon oxide films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.

    2002-02-01

    The mechanical response of plasma-enhanced chemical vapor deposited SiO2 to thermal cycling is examined by substrate curvature measurement and depth-sensing indentation. Film properties of deposition stress and stress hysteresis that accompanied thermal cycling are elucidated, as well as modulus, hardness, and coefficient of thermal expansion. Thermal cycling is shown to result in major plastic deformation of the film and a switch from a compressive to a tensile state of stress; both athermal and thermal components of the net stress alter in different ways during cycling. A mechanism of hydrogen incorporation and release from as-deposited silanol groups is proposed that accounts for the change in film properties and state of stress.

  18. Structured nanocarbon on various metal foils by microwave plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Rius, G; Yoshimura, M

    2013-01-01

    We present a versatile process for the engineering of nanostructures made of crystalline carbon on metal foils. The single step process by microwave plasma-enhance chemical vapor deposition is demonstrated for various substrate materials, such as Ni or Cu. Either carbon nanotubes (CNT) or carbon nanowalls (CNW) are obtained under same growth conditions and without the need of additional catalyst. The use of spacer and insulator implies a certain control over the kind of allotropes that are obtained. High density and large surface area are morphological characteristics of the thus obtained C products. The possibility of application on many metals, and in the alloy composition, on as-delivered commercially available foils indicates that this strategy can be adapted to a bunch of specific applications, while the production of C nanostructures is of remarkable simplicity.

  19. Morphology and structure of Ti-doped diamond films prepared by microwave plasma chemical vapor deposition

    Science.gov (United States)

    Liu, Xuejie; Lu, Pengfei; Wang, Hongchao; Ren, Yuan; Tan, Xin; Sun, Shiyang; Jia, Huiling

    2018-06-01

    Ti-doped diamond films were deposited through a microwave plasma chemical vapor deposition (MPCVD) system for the first time. The effects of the addition of Ti on the morphology, microstructure and quality of diamond films were systematically investigated. Secondary ion mass spectrometry results show that Ti can be added to diamond films through the MPCVD system using tetra n-butyl titanate as precursor. The spectra from X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy and the images from scanning electron microscopy of the deposited films indicate that the diamond phase clearly exists and dominates in Ti-doped diamond films. The amount of Ti added obviously influences film morphology and the preferred orientation of the crystals. Ti doping is beneficial to the second nucleation and the growth of the (1 1 0) faceted grains.

  20. Plasma chemical and electrical modelling of a negative DC corona in pure oxygen

    International Nuclear Information System (INIS)

    Soria, C; Pontiga, F; Castellanos, A

    2004-01-01

    A complex plasma chemical and electrical model of a negative stationary wire-to-cylinder corona discharge in pure oxygen is presented. The corona discharge is assumed to have axial and azimuthal symmetry. The experimental current-voltage characteristic is required as input data, but there are no other adjustable or empirical parameters. The experimental validation of the results of the model comes from its prediction of the ozone concentration. The role played by different reactions and species is analysed in detail using the results of the simulation. The effect of the gas temperature and of the decomposition of ozone at the electrodes is also investigated. The agreement between the model and the experiments is excellent when the effect of ozone decomposition at the electrodes is taken into account

  1. Preparation of carbon nanotubes with different morphology by microwave plasma enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duraia, El-Shazly M. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan); Mansurov, Zulkhair [Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Tokmoldin, S.Zh. [Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan)

    2010-04-15

    In this work we present a part of our results about the preparation of carbon nanotube with different morphologies by using microwave plasma enhanced chemical vapour deposition MPECVD. Well aligned, curly, carbon nanosheets, coiled carbon sheets and carbon microcoils have been prepared. We have investigated the effect of the different growth condition parameters such as the growth temperature, pressure and the hydrogen to methane flow rate ratio on the morphology of the carbon nanotubes. The results showed that there is a great dependence of the morphology of carbon nanotubes on these parameters. The yield of the carbon microcoils was high when the growth temperature was 700 C. There is a linear relation between the growth rate and the methane to hydrogen ratio. The effect of the gas pressure on the CNTs was also studied. Our samples were investigated by scanning electron microscope and Raman spectroscopy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Microwave plasma chemical synthesis of nanocrystalline carbon film structures and study their properties

    Science.gov (United States)

    Bushuev, N.; Yafarov, R.; Timoshenkov, V.; Orlov, S.; Starykh, D.

    2015-08-01

    The self-organization effect of diamond nanocrystals in polymer-graphite and carbon films is detected. The carbon materials deposition was carried from ethanol vapors out at low pressure using a highly non-equilibrium microwave plasma. Deposition processes of carbon film structures (diamond, graphite, graphene) is defined. Deposition processes of nanocrystalline structures containing diamond and graphite phases in different volume ratios is identified. The solid film was obtained under different conditions of microwave plasma chemical synthesis. We investigated the electrical properties of the nanocrystalline carbon films and identified it's from various factors. Influence of diamond-graphite film deposition mode in non-equilibrium microwave plasma at low pressure on emission characteristics was established. This effect is justified using the cluster model of the structure of amorphous carbon. It was shown that the reduction of bound hydrogen in carbon structures leads to a decrease in the threshold electric field of emission from 20-30 V/m to 5 V/m. Reducing the operating voltage field emission can improve mechanical stability of the synthesized film diamond-graphite emitters. Current density emission at least 20 A/cm2 was obtained. Nanocrystalline carbon film materials can be used to create a variety of functional elements in micro- and nanoelectronics and photonics such as cold electron source for emission in vacuum devices, photonic devices, cathodoluminescent flat display, highly efficient white light sources. The obtained graphene carbon net structure (with a net size about 6 μm) may be used for the manufacture of large-area transparent electrode for solar cells and cathodoluminescent light sources

  3. Controlled surface diffusion in plasma-enhanced chemical vapor deposition of GaN nanowires

    International Nuclear Information System (INIS)

    Hou, W C; Hong, Franklin Chau-Nan

    2009-01-01

    This study investigates the growth of GaN nanowires by controlling the surface diffusion of Ga species on sapphire in a plasma-enhanced chemical vapor deposition (CVD) system. Under nitrogen-rich growth conditions, Ga has a tendency to adsorb on the substrate surface diffusing to nanowires to contribute to their growth. The significance of surface diffusion on the growth of nanowires is dependent on the environment of the nanowire on the substrate surface as well as the gas phase species and compositions. Under nitrogen-rich growth conditions, the growth rate is strongly dependent on the surface diffusion of gallium, but the addition of 5% hydrogen in nitrogen plasma instantly diminishes the surface diffusion effect. Gallium desorbs easily from the surface by reaction with hydrogen. On the other hand, under gallium-rich growth conditions, nanowire growth is shown to be dominated by the gas phase deposition, with negligible contribution from surface diffusion. This is the first study reporting the inhibition of surface diffusion effects by hydrogen addition, which can be useful in tailoring the growth and characteristics of nanowires. Without any evidence of direct deposition on the nanowire surface, gallium and nitrogen are shown to dissolve into the catalyst for growing the nanowires at 900 deg. C.

  4. Structural and chemical analysis of annealed plasma-enhanced atomic layer deposition aluminum nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Broas, Mikael, E-mail: mikael.broas@aalto.fi; Vuorinen, Vesa [Department of Electrical Engineering and Automation, Aalto University, P.O. Box 13500, FIN-00076 Aalto, Espoo (Finland); Sippola, Perttu; Pyymaki Perros, Alexander; Lipsanen, Harri [Department of Micro- and Nanosciences, Aalto University, P.O. Box 13500, FIN-00076 Aalto, Espoo (Finland); Sajavaara, Timo [Department of Physics, University of Jyväskylä, P.O. Box 35, FIN-40014 Jyväskylä (Finland); Paulasto-Kröckel, Mervi [Department of Electrical Engineering and Automation, Aalto University. P.O. Box 13500, FIN-00076 Aalto, Espoo (Finland)

    2016-07-15

    Plasma-enhanced atomic layer deposition was utilized to grow aluminum nitride (AlN) films on Si from trimethylaluminum and N{sub 2}:H{sub 2} plasma at 200 °C. Thermal treatments were then applied on the films which caused changes in their chemical composition and nanostructure. These changes were observed to manifest in the refractive indices and densities of the films. The AlN films were identified to contain light element impurities, namely, H, C, and excess N due to nonideal precursor reactions. Oxygen contamination was also identified in the films. Many of the embedded impurities became volatile in the elevated annealing temperatures. Most notably, high amounts of H were observed to desorb from the AlN films. Furthermore, dinitrogen triple bonds were identified with infrared spectroscopy in the films. The triple bonds broke after annealing at 1000 °C for 1 h which likely caused enhanced hydrolysis of the films. The nanostructure of the films was identified to be amorphous in the as-deposited state and to become nanocrystalline after 1 h of annealing at 1000 °C.

  5. pypk - A Python extension module to handle chemical kinetics in plasma physics modeling

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available PLASMAKIN is a package to handle physical and chemical data used in plasma physics modeling and to compute gas-phase and gas-surface kinetics data: particle production and loss rates, photon emission spectra and energy exchange rates. A large number of species properties and reaction types are supported, namely: gas or electron temperature dependent collision rate coefficients, vibrational and cascade levels, evaluation of branching ratios, superelastic and other reverse processes, three-body collisions, radiation imprisonment and photoelectric emission. Support of non-standard rate coefficient functions can be handled by a user-supplied shared library.

    The main block of the PLASMAKIN package is a Fortran module that can be included in an user's program or compiled as a shared library, libpk. pypk is a new addition to the package and provides access to libpk from Python programs. It is build on top of the ctypes foreign function library module and is prepared to work with several Fortran compilers. However pypk is more than a wrapper and provides its own classes and functions taking advantage of Python language characteristics. Integration with Python tools allows substantial productivity gains on program development and insight on plasma physics problems.

  6. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J. [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington, DC 20015 (United States)

    2015-11-02

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH{sub 4}/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H{sub 2} into the deposition gas chemistry. Electronically excited species of CN, C{sub 2}, Ar, N{sub 2}, CH, H{sub β}, and H{sub α} were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T{sub 2g} phonon at 1333 cm{sup −1} peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.

  7. Hydrogen plasma enhanced alignment on CNT-STM tips grown by liquid catalyst-assisted microwave plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Tung, Fa-Kuei; Yoshimura, Masamichi; Ueda, Kazuyuki; Ohira, Yutaka; Tanji, Takayoshi

    2008-01-01

    Carbon nanotubes are grown directly on a scanning tunneling microscopy tip by liquid catalyst-assisted microwave-enhanced chemical vapor deposition, and effects of hydrogen plasma treatment on the tip have been investigated in detail by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. The unaligned CNTs on the as-grown tip apex have been realigned and reshaped by subsequent hydrogen plasma treatment. The diameter of CNTs is enlarged mainly due to amorphous layers being re-sputtered over their outer shells

  8. Expanding Thermal Plasma Chemical Vapour Deposition of ZnO:Al Layers for CIGS Solar Cells

    Directory of Open Access Journals (Sweden)

    K. Sharma

    2014-01-01

    Full Text Available Aluminium-doped zinc oxide (ZnO:Al grown by expanding thermal plasma chemical vapour deposition (ETP-CVD has demonstrated excellent electrical and optical properties, which make it an attractive candidate as a transparent conductive oxide for photovoltaic applications. However, when depositing ZnO:Al on CIGS solar cell stacks, one should be aware that high substrate temperature processing (i.e., >200°C can damage the crucial underlying layers/interfaces (such as CIGS/CdS and CdS/i-ZnO. In this paper, the potential of adopting ETP-CVD ZnO:Al in CIGS solar cells is assessed: the effect of substrate temperature during film deposition on both the electrical properties of the ZnO:Al and the eventual performance of the CIGS solar cells was investigated. For ZnO:Al films grown using the high thermal budget (HTB condition, lower resistivities, ρ, were achievable (~5 × 10−4 Ω·cm than those grown using the low thermal budget (LTB conditions (~2 × 10−3 Ω·cm, whereas higher CIGS conversion efficiencies were obtained for the LTB condition (up to 10.9% than for the HTB condition (up to 9.0%. Whereas such temperature-dependence of CIGS device parameters has previously been linked with chemical migration between individual layers, we demonstrate that in this case it is primarily attributed to the prevalence of shunt currents.

  9. Organo-Functionalization of Silicon Nanocrystals Synthesized by Inductively Coupled Plasma Chemical Vapor Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Don-Sung; Choe, Dong-Hoe; Jeong, Hyun-Dam [Chonnam National University, Gwangju (Korea, Republic of); Yoo, Seung-Wan; Kim, Jung-Hyung [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2016-05-15

    Octadecyl-terminated silicon nanocrystals (ODE-Si NCs) are obtained via a surface-initiated thermal hydrosilylation reaction on hydride-terminated Si NCs (H-Si NCs). Pristine Si NCs were synthesized at the gram scale by using inductively coupled plasma chemical vapor deposition (ICP-CVD) . The H-Si NCs were produced through a chemical etching process with hydrofluoric acid (HF), ethanol (EtOH), and distilled water (d-H{sub 2}O). The results obtained from X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) indicate that the synthesized Si NCs obtained via ICP-CVD have diamond cubic-structured silicon with a grain size of 10 nm and a densely packed Si NC array consisting of individual NCs. Organo-functionalized Si NCs, i.e., ODE-Si NCs, are well soluble in organic solvent whereas pristine Si NCs synthesized through ICP-CVD are not. The surface chemistry of the ODE-Si NCs was confirmed via Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy ({sup 1}H-NMR), and field emission transmission electron microscopy (FE-TEM). Thereby, these newly synthesized and scalable organo-functionalized Si NCs are applicable as raw materials for practical use in devices by tuning the surface chemistry with various capping molecules.

  10. Chemically produced nanostructured ODS-lanthanum oxide-tungsten composites sintered by spark plasma

    International Nuclear Information System (INIS)

    Yar, Mazher Ahmed; Wahlberg, Sverker; Bergqvist, Hans; Salem, Hanadi G.; Johnsson, Mats; Muhammed, Mamoun

    2011-01-01

    High purity W and W-0.9La 2 O 3 (wt.%) nanopowders were produced by a wet chemical route. The precursor was prepared by the reaction of ammonium paratungstate (APT) with lanthanum salt in aqueous solutions. High resolution electron microscopy investigations revealed that the tungstate particles were coated with oxide precipitates. The precursor powder was reduced to tungsten metal with dispersed lanthanum oxide. Powders were consolidated by spark plasma sintering (SPS) at 1300 and 1400 o C to suppress grain growth during sintering. The final grain size relates to the SPS conditions, i.e. temperature and heating rate, regardless of the starting powder particle size. Scanning electron microscopy revealed that oxide phases were mainly accumulated at grain boundaries while the tungsten matrix constituted of nanosized sub-grains. The transmission electron microscopy revealed that the tungsten grains consist of micron-scale grains and finer sub-grains. EDX analysis confirmed the presence of W in dispersed oxide phases with varying chemical composition, which evidenced the presence of complex oxide phases (W-O-La) in the sintered metals.

  11. Chemical corrosion by chlorides on ancient-like bronzes and treatment by hydrogen glow discharge plasma

    Science.gov (United States)

    Papadopoulou, O.; Novakovic, J.; Vassiliou, P.; Filippaki, E.; Bassiakos, Y.

    2013-12-01

    Three representative ancient-like bronzes are employed for the chemical synthesis of Cu2(OH)3Cl rich patinas in order to study the influence of the alloying elements in the evolution of the chloride attack and to further conduct stabilization treatment via Hydrogen Glow Discharge Plasma (HGDP) at low temperature and pressure. The corrosion behavior of specimens having Sn and Pb as main alloying elements is governed by a decuprification mechanism and by the formation of Sn-Pb-O enriched barrier layers. In the case of the Zn containing alloy, dezincification is more pronounced at the corrosion initial stages, and copper species predominate the corrosion products evolution. A three-hour HGDP treatment leads to Cu+ production and metallic Cu, Sn, Zn, and Pb redeposition, as a result of metal cation reduction. This process is accompanied by partial removal of Cl species, O diminution, and change in coloration. The further increase of the Cl/O atomic ratio measured on the post-treated surfaces leads to the formation of nantokite and thus to the conclusion that the stabilization of objects with extensive Cl attack is not feasible by HGDP without preliminary chemical treatment.

  12. Fast screening of analytes for chemical reactions by reactive low-temperature plasma ionization mass spectrometry.

    Science.gov (United States)

    Zhang, Wei; Huang, Guangming

    2015-11-15

    Approaches for analyte screening have been used to aid in the fine-tuning of chemical reactions. Herein, we present a simple and straightforward analyte screening method for chemical reactions via reactive low-temperature plasma ionization mass spectrometry (reactive LTP-MS). Solution-phase reagents deposited on sample substrates were desorbed into the vapor phase by action of the LTP and by thermal desorption. Treated with LTP, both reagents reacted through a vapor phase ion/molecule reaction to generate the product. Finally, protonated reagents and products were identified by LTP-MS. Reaction products from imine formation reaction, Eschweiler-Clarke methylation and the Eberlin reaction were detected via reactive LTP-MS. Products from the imine formation reaction with reagents substituted with different functional groups (26 out of 28 trials) were successfully screened in a time of 30 s each. Besides, two short-lived reactive intermediates of Eschweiler-Clarke methylation were also detected. LTP in this study serves both as an ambient ionization source for analyte identification (including reagents, intermediates and products) and as a means to produce reagent ions to assist gas-phase ion/molecule reactions. The present reactive LTP-MS method enables fast screening for several analytes from several chemical reactions, which possesses good reagent compatibility and the potential to perform high-throughput analyte screening. In addition, with the detection of various reactive intermediates (intermediates I and II of Eschweiler-Clarke methylation), the present method would also contribute to revealing and elucidating reaction mechanisms. Copyright © 2015 John Wiley & Sons, Ltd.

  13. Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

    Energy Technology Data Exchange (ETDEWEB)

    Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Rytlewski, Piotr [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, ul. M. Skłodowskiej–Curie 55, 87-100 Toruń (Poland); Żenkiewicz, Marian [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland)

    2015-08-15

    Highlights: • We modified polylactide surface layer with chemical, plasma or laser methods. • We tested selected properties and surface structure of modified samples. • We stated that the plasma treatment appears to be the most beneficial. - Abstract: The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm{sup 2} was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

  14. Controlling the resistivity gradient in aluminum-doped zinc oxide grown by plasma-enhanced chemical vapor deposition

    NARCIS (Netherlands)

    Ponomarev, M.; Verheijen, M.A.; Keuning, W.; Sanden, van de M.C.M.; Creatore, M.

    2012-01-01

    Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO:Al layers by focusing on the control

  15. Structural and optical characterization of self-assembled Ge nanocrystal layers grown by plasma-enhanced chemical vapor deposition

    NARCIS (Netherlands)

    Saeed, S.; Buters, F.; Dohnalova, K.; Wosinski, L.; Gregorkiewicz, T.

    2014-01-01

    We present a structural and optical study of solid-state dispersions of Ge nanocrystals prepared by plasma-enhanced chemical vapor deposition. Structural analysis shows the presence of nanocrystalline germanium inclusions embedded in an amorphous matrix of Si-rich SiO2. Optical characterization

  16. A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods

    International Nuclear Information System (INIS)

    Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu; Inoue, Toru

    2009-01-01

    In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm 3 regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.

  17. A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods

    Science.gov (United States)

    Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu; Inoue, Toru

    2009-06-01

    In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm3 regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.

  18. Plasma-enhanced chemical vapor deposited silicon oxynitride films for optical waveguide bridges for use in mechanical sensors

    DEFF Research Database (Denmark)

    Storgaard-Larsen, Torben; Leistiko, Otto

    1997-01-01

    In this paper the influence of RF power, ammonia flow, annealing temperature, and annealing time on the optical and mechanical properties of plasma-enhanced chemically vapor deposited silicon oxynitride films, is presented. A low refractive index (1.47 to 1.48) film having tensile stress has been...

  19. Comparisons of physical and chemical sputtering in high density divertor plasmas with the Monte Carlo Impurity (MCI) transport model

    International Nuclear Information System (INIS)

    Evans, T.E.; Loh, Y.S.; West, W.P.; Finkenthal, D.F.

    1997-11-01

    The MCI transport model was used to compare chemical and physical sputtering for a DIII-D divertor plasma near detachment. With physical sputtering alone the integrated carbon influx was 8.4 x 10 19 neutral/s while physical plus chemical sputtering produced an integrated carbon influx of 1.7 x 10 21 neutrals/s. The average carbon concentration in the computational volume increased from 0.012% with only physical sputtering to 0.182% with both chemical and physical sputtering. This increase in the carbon inventory produced more radiated power which is in better agreement with experimental measurements

  20. Comparative X-ray photoelectron spectroscopy study of plasma enhanced chemical vapor deposition and micro pressure chemical vapor deposition of phosphorus silicate glass layers after rapid thermal annealing

    International Nuclear Information System (INIS)

    Beshkov, G.; Krastev, V.; Gogova, D.; Talik, E.; Adamies, M.

    2008-01-01

    In this paper the bonding state of Phosphorus Silicate Glass (PSG) layers obtained by two different technological approaches, i.e. in two types of reactors: Plasma Enhanced Chemical Vapor Deposition (PECVD) and Micro Pressure Chemical Vapor Deposition (MPCVD) are investigated employing XPS and AES. The PSG layers are deposited at 380 0 C and 420 0 C in corresponding reactors. XPS and AES analyses show that Si2p peak recorded from PECVD layers are not as expected at their position characteristics of silicon dioxide but instead they are at the characteristic of elemental silicon. Plasma enhancement during deposition leads to less oxidized and more inhomogeneous layer. After rapid thermal annealing the Si2p peak is situated at position characteristic of silicon dioxide. (authors)

  1. High-performance metabolic profiling of plasma from seven mammalian species for simultaneous environmental chemical surveillance and bioeffect monitoring.

    Science.gov (United States)

    Park, Youngja H; Lee, Kichun; Soltow, Quinlyn A; Strobel, Frederick H; Brigham, Kenneth L; Parker, Richard E; Wilson, Mark E; Sutliff, Roy L; Mansfield, Keith G; Wachtman, Lynn M; Ziegler, Thomas R; Jones, Dean P

    2012-05-16

    High-performance metabolic profiling (HPMP) by Fourier-transform mass spectrometry coupled to liquid chromatography gives relative quantification of thousands of chemicals in biologic samples but has had little development for use in toxicology research. In principle, the approach could be useful to detect complex metabolic response patterns to toxicologic exposures and to detect unusual abundances or patterns of potentially toxic chemicals. As an initial study to develop these possible uses, we applied HPMP and bioinformatics analysis to plasma of humans, rhesus macaques, marmosets, pigs, sheep, rats and mice to determine: (1) whether more chemicals are detected in humans living in a less controlled environment than captive species and (2) whether a subset of plasma chemicals with similar inter-species and intra-species variation could be identified for use in comparative toxicology. Results show that the number of chemicals detected was similar in humans (3221) and other species (range 2537-3373). Metabolite patterns were most similar within species and separated samples according to family and order. A total of 1485 chemicals were common to all species; 37% of these matched chemicals in human metabolomic databases and included chemicals in 137 out of 146 human metabolic pathways. Probability-based modularity clustering separated 644 chemicals, including many endogenous metabolites, with inter-species variation similar to intra-species variation. The remaining chemicals had greater inter-species variation and included environmental chemicals as well as GSH and methionine. Together, the data suggest that HPMP provides a platform that can be useful within human populations and controlled animal studies to simultaneously evaluate environmental exposures and biological responses to such exposures. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Wearable Atmospheric Pressure Plasma Fabrics Produced by Knitting Flexible Wire Electrodes for the Decontamination of Chemical Warfare Agents

    Science.gov (United States)

    Jung, Heesoo; Seo, Jin Ah; Choi, Seungki

    2017-01-01

    One of the key reasons for the limited use of atmospheric pressure plasma (APP) is its inability to treat non-flat, three-dimensional (3D) surface structures, such as electronic devices and the human body, because of the rigid electrode structure required. In this study, a new APP system design—wearable APP (WAPP)—that utilizes a knitting technique to assemble flexible co-axial wire electrodes into a large-area plasma fabric is presented. The WAPP device operates in ambient air with a fully enclosed power electrode and grounded outer electrode. The plasma fabric is flexible and lightweight, and it can be scaled up for larger areas, making it attractive for wearable APP applications. Here, we report the various plasma properties of the WAPP device and successful test results showing the decontamination of toxic chemical warfare agents, namely, mustard (HD), soman (GD), and nerve (VX) agents.

  3. Investigation of detached recombining deuterium plasma and carbon chemical erosion in the toroidal divertor simulator NAGDIS-T

    International Nuclear Information System (INIS)

    Yada, K.; Matsui, N.; Ohno, N.; Kajita, S.; Takamura, S.; Takagi, M.

    2009-01-01

    Detached deuterium recombining plasma has been generated in the toroidal divertor simulator. The electron temperature (0.1-0.4 eV) and density (∼10 18 m -3 ) in the detached plasmas were evaluated with a spectroscopic method using a series of deuterium Balmer line emission from highly excited levels and the Stark broadening of D(2-12). We have investigated the role of volume plasma recombination through Electron-Ion Recombination (EIR) and Molecular Activated Recombination (MAR) processes. Moreover, the carbon erosion in the detached deuterium plasma has been studied with a weight loss method. It is found that deuterium neutrals generated by EIR process could have strong influence on the carbon chemical erosion.

  4. Observation of non-chemical equilibrium effect on Ar-CO2-H2 thermal plasma model by changing pressure

    International Nuclear Information System (INIS)

    Al-Mamun, Sharif Abdullah; Tanaka, Yasunori; Uesugi, Yoshihiko

    2009-01-01

    The authors developed a two-dimensional one-temperature chemical non-equilibrium (1T-NCE) model of Ar-CO 2 -H 2 inductively coupled thermal plasmas (ICTP) to investigate the effect of pressure variation. The basic concept of one-temperature model is the assumption and treatment of the same energy conservation equation for electrons and heavy particles. The energy conservation equations consider reaction heat effects and energy transfer among the species produced as well as enthalpy flow resulting from diffusion. Assuming twenty two (22) different particles in this model and by solving mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from hundred and ninety eight (198) chemical reactions, chemical non-equilibrium effects were taken into account. Transport and thermodynamic properties of Ar-CO 2 -H 2 thermal plasmas were self-consistently calculated using the first-order approximation of the Chapman-Enskog method. Finally results obtained at atmospheric pressure (760 Torr) and at reduced pressure (500, 300 Torr) were compared with results from one-temperature chemical equilibrium (1T-CE) model. And of course, this comparison supported discussion of chemical non-equilibrium effects in the inductively coupled thermal plasmas (ICTP).

  5. Effect of oxygen plasma on field emission characteristics of single-wall carbon nanotubes grown by plasma enhanced chemical vapour deposition system

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avshish; Parveen, Shama; Husain, Samina; Ali, Javid; Zulfequar, Mohammad [Department of Physics, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Harsh [Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia, New Delhi 110025 (India); Husain, Mushahid, E-mail: mush-reslab@rediffmail.com [Department of Physics, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia, New Delhi 110025 (India)

    2014-02-28

    Field emission properties of single wall carbon nanotubes (SWCNTs) grown on iron catalyst film by plasma enhanced chemical vapour deposition system were studied in diode configuration. The results were analysed in the framework of Fowler-Nordheim theory. The grown SWCNTs were found to be excellent field emitters, having emission current density higher than 20 mA/cm{sup 2} at a turn-on field of 1.3 V/μm. The as grown SWCNTs were further treated with Oxygen (O{sub 2}) plasma for 5 min and again field emission characteristics were measured. The O{sub 2} plasma treated SWCNTs have shown dramatic improvement in their field emission properties with emission current density of 111 mA/cm{sup 2} at a much lower turn on field of 0.8 V/μm. The as grown as well as plasma treated SWCNTs were also characterized by various techniques, such as scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy before and after O{sub 2} plasma treatment and the findings are being reported in this paper.

  6. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    International Nuclear Information System (INIS)

    Wen-Juan, Hu; Fen-Yan, Xie; Qiang, Chen; Jing, Weng

    2008-01-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films

  7. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    Science.gov (United States)

    Hu, Wen-Juan; Xie, Fen-Yan; Chen, Qiang; Weng, Jing

    2008-10-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films.

  8. Low-Energy Electron Scattering Data for Chemical Plasma Treatment of Biomass

    International Nuclear Information System (INIS)

    Lima, Marco A.P.

    2014-01-01

    Full text: Replacing fossil fuels with biofuels from renewable sources is an important goal for reducing greenhouse gas emissions. Many countries are already using few percent of ethanol in the gasoline and few of them, with more aggressive programs, have developed flex fuel engines that can run with any mixture of gasoline and ethanol. An important point is how to produce ethanol in a sustainable way and with which technology? Biomass is a good candidate since it has cellulose and hemicellulose as source of sugars. In order to liberate these sugars for fermentation, it is important to learn how to separate the main components. Chemical routes (acid treatment) and biological routes (enzymatic hydrolysis) are combined and used for these purposes. Atmospheric plasmas can be useful for attacking the biomass in a controlled manner and low-energy electrons may have an important role in the process. Recently we have been studying the interaction of electrons with lignin subunits (phenol, guaiacol, p-coumaryl alcohol), cellulose components, β-D-glucose and cellobiose (β(1 - 4) linked glucose dimer) and hemicellulose components (β-D-xylose). We also obtained results for the amylose subunits α-D-glucose and maltose (α(1 - 4) linked glucose dimer). Altogether, the resonance spectra of lignin, cellulose and hemicellulose components establish a physical–chemical basis for electron-induced biomass pretreatment that could be applied to biofuel production. In my talk I will give a progress report on this matter. We will also discuss microsolvation effects on the electron-phenol scattering process and present our strategy to study molecular dissociation through electronic excitation of low energy triplet states. (author)

  9. Time-Resolved Quantum Cascade Laser Absorption Spectroscopy of Pulsed Plasma Assisted Chemical Vapor Deposition Processes Containing BCl3

    Science.gov (United States)

    Lang, Norbert; Hempel, Frank; Strämke, Siegfried; Röpcke, Jürgen

    2011-08-01

    In situ measurements are reported giving insight into the plasma chemical conversion of the precursor BCl3 in industrial applications of boriding plasmas. For the online monitoring of its ground state concentration, quantum cascade laser absorption spectroscopy (QCLAS) in the mid-infrared spectral range was applied in a plasma assisted chemical vapor deposition (PACVD) reactor. A compact quantum cascade laser measurement and control system (Q-MACS) was developed to allow a flexible and completely dust-sealed optical coupling to the reactor chamber of an industrial plasma surface modification system. The process under the study was a pulsed DC plasma with periodically injected BCl3 at 200 Pa. A synchronization of the Q-MACS with the process control unit enabled an insight into individual process cycles with a sensitivity of 10-6 cm-1·Hz-1/2. Different fragmentation rates of the precursor were found during an individual process cycle. The detected BCl3 concentrations were in the order of 1014 molecules·cm-3. The reported results of in situ monitoring with QCLAS demonstrate the potential for effective optimization procedures in industrial PACVD processes.

  10. Diamond-like carbon films deposited on polycarbonates by plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Guo, C.T. [Department of Computer and Communication, Diwan College of Management, 72141 Taiwan (China)], E-mail: ctguo@dwu.edu.tw

    2008-04-30

    Diamond-like carbon films were coated on optical polycarbonate using plasma-enhanced chemical vapor deposition. A mixture of SiH{sub 4} and CH{sub 4}/H{sub 2} gases was utilized to reduce the internal compressive stress of the deposited films. The structure of the DLC films was characterized as a function of film thickness using Raman spectroscopy. The dependence of G peak positions and the intensity ratio of I{sub D}/I{sub G} on the DLC film thicknesses was analyzed in detail. Other studies involving atomic force microscopy, ultraviolet visible spectrometry, and three adhesion tests were conducted. Good transparency in the visible region, and good adhesion between diamond-like carbon films and polycarbonate were demonstrated. One-time recordings before and after a DLC film was coated on compact rewritable disc substrates were analyzed as a case study. The results reveal that the diamond-like carbon film overcoating the optical polycarbonates effectively protects the storage media.

  11. Optimization of silicon oxynitrides by plasma-enhanced chemical vapor deposition for an interferometric biosensor

    Science.gov (United States)

    Choo, Sung Joong; Lee, Byung-Chul; Lee, Sang-Myung; Park, Jung Ho; Shin, Hyun-Joon

    2009-09-01

    In this paper, silicon oxynitride layers deposited with different plasma-enhanced chemical vapor deposition (PECVD) conditions were fabricated and optimized, in order to make an interferometric sensor for detecting biochemical reactions. For the optimization of PECVD silicon oxynitride layers, the influence of the N2O/SiH4 gas flow ratio was investigated. RF power in the PEVCD process was also adjusted under the optimized N2O/SiH4 gas flow ratio. The optimized silicon oxynitride layer was deposited with 15 W in chamber under 25/150 sccm of N2O/SiH4 gas flow rates. The clad layer was deposited with 20 W in chamber under 400/150 sccm of N2O/SiH4 gas flow condition. An integrated Mach-Zehnder interferometric biosensor based on optical waveguide technology was fabricated under the optimized PECVD conditions. The adsorption reaction between bovine serum albumin (BSA) and the silicon oxynitride surface was performed and verified with this device.

  12. Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Santra, T. S.; Liu, C. H.; Bhattacharyya, T. K.; Patel, P.; Barik, T. K.

    2010-01-01

    Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of C-C, C-H, Si-C, and Si-H bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio I D /I G . Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).

  13. Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Santra, T S; Liu, C H [Institute of Nanoengineering and Microsystems (NEMS), National Tsing Hua University, Hsinchu, Taiwan 30043 (China); Bhattacharyya, T K [Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721302, West Bengal (India); Patel, P [Department of Electrical and Computer Engineering, University of Illinois at Urbana Champaign, Urbana, Illinois 61801 (United States); Barik, T K [School of Applied Sciences, Haldia Institute of Technology, Haldia 721657, Purba Medinipur, West Bengal (India)

    2010-06-15

    Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of C-C, C-H, Si-C, and Si-H bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio I{sub D}/I{sub G}. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).

  14. Electrical transport properties of graphene nanowalls grown at low temperature using plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Zhao, Rong; Ahktar, Meysam; Alruqi, Adel; Dharmasena, Ruchira; Jasinski, Jacek B.; Thantirige, Rukshan M.; Sumanasekera, Gamini U.

    2017-05-01

    In this work, we report the electrical transport properties of uniform and vertically oriented graphene (graphene nanowalls) directly synthesized on multiple substrates including glass, Si/SiO2 wafers, and copper foils using radio-frequency plasma enhanced chemical vapor deposition (PECVD) with methane (CH4) as the precursor at relatively low temperatures. The temperature for optimum growth was established with the aid of transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy. This approach offers means for low-cost graphene nanowalls growth on an arbitrary substrate with the added advantage of transfer-free device fabrication. The temperature dependence of the electrical transport properties (resistivity and thermopower) were studied in the temperature range, 30-300 K and analyzed with a combination of 2D-variable range hopping (VRH) and thermally activated (TA) conduction mechanisms. An anomalous temperature dependence of the thermopower was observed for all the samples and explained with a combination of a diffusion term having a linear temperature dependence plus a term with an inverse temperature dependence.

  15. Microwave plasma-assisted chemical vapor deposition of porous carbon film as supercapacitive electrodes

    Science.gov (United States)

    Wu, Ai-Min; Feng, Chen-Chen; Huang, Hao; Paredes Camacho, Ramon Alberto; Gao, Song; Lei, Ming-Kai; Cao, Guo-Zhong

    2017-07-01

    Highly porous carbon film (PCF) coated on nickel foam was prepared successfully by microwave plasma-assisted chemical vapor deposition (MPCVD) with C2H2 as carbon source and Ar as discharge gas. The PCF is uniform and dense with 3D-crosslinked nanoscale network structure possessing high degree of graphitization. When used as the electrode material in an electrochemical supercapacitor, the PCF samples verify their advantageous electrical conductivity, ion contact and electrochemical stability. The test results show that the sample prepared under 1000 W microwave power has good electrochemical performance. It displays the specific capacitance of 62.75 F/g at the current density of 2.0 A/g and retains 95% of its capacitance after 10,000 cycles at the current density of 2.0 A/g. Besides, its near-rectangular shape of the cyclic voltammograms (CV) curves exhibits typical character of an electric double-layer capacitor, which owns an enhanced ionic diffusion that can fit the requirements for energy storage applications.

  16. Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Gates, S. M.; Neumayer, D. A.; Sherwood, M. H.; Grill, A.; Wang, X.; Sankarapandian, M.

    2007-01-01

    The preparation of ultralow dielectric constant porous silicon, carbon, oxygen, hydrogen alloy dielectrics, called 'pSiCOH', using a production 200 mm plasma enhanced chemical vapor deposition tool and a thermal treatment is reported here. The effect of deposition temperature on the pSiCOH film is examined using Fourier transform infrared (FTIR) spectroscopy, dielectric constant (k), and film shrinkage measurements. For all deposition temperatures, carbon in the final porous film is shown to be predominantly Si-CH 3 species, and lower k is shown to correlate with increased concentration of Si-CH 3 . NMR and FTIR spectroscopies clearly detect the loss of a removable, unstable, hydrocarbon (CH x ) phase during the thermal treatment. Also detected are increased cross-linking of the Si-O skeleton, and concentration changes for three distinct structures of carbon. In the as deposited films, deposition temperature also affects the hydrocarbon (CH x ) content and the presence of C=O and C=C functional groups

  17. Spark plasma sintering of tungsten-yttrium oxide composites from chemically synthesized nanopowders and microstructural characterization

    International Nuclear Information System (INIS)

    Yar, M.A.; Wahlberg, Sverker; Bergqvist, Hans; Salem, H.G.; Johnsson, Mats; Muhammed, Mamoun

    2011-01-01

    Nano-crystalline W-1%Y 2 O 3 (wt.%) powder was produced by a modified solution chemical reaction of ammonium paratungstate (APT) and yttrium nitrate. The precursor powder was found to consist of particles of bimodal morphology i.e. large APT-like particles up to 20 μm and rectangular yttrium containing ultrafine plates. After thermal processing tungsten crystals were evolved from W-O-Y plate like particles. spark plasma sintering (SPS) was used to consolidate the powder at 1100 and 1200 deg. C for different holding times in order to optimize the sintering conditions to yield high density but with reduced grain growth. Dispersion of yttrium oxide enhanced the sinterability of W powder with respect to lanthanum oxide. W-1%Y 2 O 3 composites with sub-micron grain size showed improved density and mechanical properties as compared to W-La 2 O 3 composites. Sample sintered in two steps showed improved density, due to longer holding time at lower temperature (900 deg. C) and less grain growth due to shorter holding time at higher temperature i.e. 1 min at 1100 deg. C.

  18. Characterisation of silicon carbide films deposited by plasma-enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Iliescu, Ciprian; Chen Bangtao; Wei Jiashen; Pang, A.J.

    2008-01-01

    The paper presents a characterisation of amorphous silicon carbide films deposited in plasma-enhanced chemical vapour deposition (PECVD) reactors for MEMS applications. The main parameter was optimised in order to achieve a low stress and high deposition rate. We noticed that the high frequency mode (13.56 MHz) gives a low stress value which can be tuned from tensile to compressive by selecting the correct power. The low frequency mode (380 kHz) generates high compressive stress (around 500 MPa) due to ion bombardment and, as a result, densification of the layer achieved. Temperature can decrease the compressive value of the stress (due to annealing effect). A low etching rate of the amorphous silicon carbide layer was noticed for wet etching in KOH 30% at 80 o C (around 13 A/min) while in HF 49% the layer is practically inert. A very slow etching rate of amorphous silicon carbide layer in XeF 2 -7 A/min- was observed. The paper presents an example of this application: PECVD-amorphous silicon carbide cantilevers fabricated using surface micromachining by dry-released technique in XeF 2

  19. Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

    International Nuclear Information System (INIS)

    Johnson, Kyle W.; Guruvenket, Srinivasan; Sailer, Robert A.; Ahrenkiel, S. Phillip; Schulz, Douglas L.

    2013-01-01

    Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H 2 O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF 2 . • Carbonaceous contamination from the precursor was minimal

  20. Characteristics of SiOx-containing hard film prepared by low temperature plasma enhanced chemical vapor deposition using hexamethyldisilazane or vinyltrimethylsilane and post oxygen plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yi-Syuan; Liu, Wan-Yu; Wu, Hsin-Ming [Department of Materials Engineering, Tatung University, Taipei, 104, Taiwan (China); Chen, Ko-Shao, E-mail: kschen@ttu.edu.tw [Department of Materials Engineering, Tatung University, Taipei, 104, Taiwan (China); Cech, Vladimir [Institute of Materials Chemistry, Brno University of Technology (Czech Republic)

    2017-03-01

    This study, monomers of hexamethyldisilazane (HMDSZ) and vinyltrimethylsilane (VTMS) were respectively used to deposit on the surface of polyethylene terephthalate (PET) substrate by plasma enhanced chemical vapor deposition. Oxygen plasma treatment follows the HMDSZ and VTMS deposition to produce a hydrophilic surface film on the deposited surface. Time for HMDSZ and VTMS plasma deposition was changed to investigate its influences on water contact angle, deposited film thickness, refractive index, and friction coefficient properties. The surface morphologies of the processed samples were observed by scanning electron microscope and their chemical compositions were measured by X-ray photoelectron spectroscopy. At 550 nm wavelength, the optical transmittance of PET after the HMDSZ treatment decreases from 89% to 83%, but increases from 89% to 95% for the VTMS treatment. With increase in HMDSZ and VTMS deposition times, the film thickness increases and the refractive index decreases. Result revealed by XPS, SiO{sub 2} film is formed on the sample surface after the O{sub 2} plasma treatment. The film adhesion capability by the HMDSZ+O{sub 2} and VTMS+O{sub 2} treatment was stronger than that by the HMDSZ and VTMS treatment only. The SiOx films produced by HMDSZ+O{sub 2} and VTMS+O{sub 2} treatment can increase the film hardness and improve light transmittance. - Highlights: • With increase in HMDSZ and VTMS deposition times, the film thickness increases and the refractive index decreases. • The optical transmittance of PET after the VTMS treatment increases from 89% to 95%. • The SiO{sub 2} films deposited by HMDSZ+O{sub 2} and VTMS+O{sub 2} plasma can increase the film hardness and improve light transmittance. • It is expected that they can be applied to the optical transmittance protective film on plastic substrate in the future.

  1. Gene expression responses of HeLa cells to chemical species generated by an atmospheric plasma flow

    International Nuclear Information System (INIS)

    Yokoyama, Mayo; Johkura, Kohei; Sato, Takehiko

    2014-01-01

    Highlights: • Response of HeLa cells to a plasma-irradiated medium was revealed by DNA microarray. • Gene expression pattern was basically different from that in a H 2 O 2 -added medium. • Prominently up-/down-regulated genes were partly shared by the two media. • Gene ontology analysis showed both similar and different responses in the two media. • Candidate genes involved in response to ROS were detected in each medium. - Abstract: Plasma irradiation generates many factors able to affect the cellular condition, and this feature has been studied for its application in the field of medicine. We previously reported that hydrogen peroxide (H 2 O 2 ) was the major cause of HeLa cell death among the chemical species generated by high level irradiation of a culture medium by atmospheric plasma. To assess the effect of plasma-induced factors on the response of live cells, HeLa cells were exposed to a medium irradiated by a non-lethal plasma flow level, and their gene expression was broadly analyzed by DNA microarray in comparison with that in a corresponding concentration of 51 μM H 2 O 2 . As a result, though the cell viability was sufficiently maintained at more than 90% in both cases, the plasma-medium had a greater impact on it than the H 2 O 2 -medium. Hierarchical clustering analysis revealed fundamentally different cellular responses between these two media. A larger population of genes was upregulated in the plasma-medium, whereas genes were downregulated in the H 2 O 2 -medium. However, a part of the genes that showed prominent differential expression was shared by them, including an immediate early gene ID2. In gene ontology analysis of upregulated genes, the plasma-medium showed more diverse ontologies than the H 2 O 2 -medium, whereas ontologies such as “response to stimulus” were common, and several genes corresponded to “response to reactive oxygen species.” Genes of AP-1 proteins, e.g., JUN and FOS, were detected and notably elevated in

  2. Tailoring of the morphology and chemical composition of thin organosilane microwave plasma polymer layers on metal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Grundmeier, G.; Thiemann, P.; Carpentier, J.; Shirtcliffe, N.; Stratmann, M

    2004-01-01

    The growth of thin microwave organosilicon plasma polymers on model zinc surfaces was investigated as a function of the film thickness and the oxygen partial pressure during film deposition. The evolution of the topology of the film was studied by atomic force microscopy (AFM). The nano- and micro-roughness was investigated at the inner and the outer surfaces of the plasma polymers. A special etching procedure was developed to reveal the underside of the plasma polymer and thereby its inner surface. Rough films contained voids at the interface, which reduced the polymer/metal contact area. The increase in oxygen partial pressure led to a smoother film growth with a perfect imitation of the substrate topography at the interface. The chemical structure of the films was determined by infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). ToF-SIMS at the outer and the inner surface of the plasma polymers showed that the density of methylsilyl groups increases in the outer surface layer of the plasma polymer and depends on the oxygen partial pressure. The chemical composition of the films could be altered to pure SiO{sub 2} without changing the morphology by using oxygen-plasma post-treatment. This was proved by means of IRRAS and AFM. Chemistry and topology of the films were correlated with the apparent water contact angle. It was found that a linear relationship exists between the nanoscopic roughness of the plasma polymer and the static contact angle of water. Superposition of a nanoscopic roughness of the metal surface and the nanoscopic roughness of methylsilyl-rich films led to ultra-hydrophobic films with water contact angles up to 160 deg.

  3. Surface chemical structure of poly(ethylene naphthalate) films during degradation in low-pressure high-frequency plasma treatments

    Science.gov (United States)

    Kamata, Noritsugu; Yuji, Toshifumi; Thungsuk, Nuttee; Arunrungrusmi, Somchai; Chansri, Pakpoom; Kinoshita, Hiroyuki; Mungkung, Narong

    2018-06-01

    The surface chemical structure of poly(ethylene naphthalate) (PEN) films treated with a low-pressure, high-frequency plasma was investigated by storing in a box at room temperature to protect the PEN film surface from dust. The functional groups on the PEN film surface changed over time. The functional groups of –C=O, –COH, and –COOH were abundant in the Ar + O2 mixture gas plasma-treated PEN samples as compared with those in untreated PEN samples. The changes occurred rapidly after 2 d following the plasma treatment, reaching steady states 8 d after the treatment. Hydrophobicity had an inverse relationship with the concentration of these functional groups on the surface. Thus, the effect of the low-pressure high-frequency plasma treatment on PEN varies as a function of storage time. This means that radical oxygen and oxygen molecules are clearly generated in the plasma, and this is one index to confirm that radical reaction has definitely occurred between the gas and the PEN film surface with a low-pressure high-frequency plasma.

  4. On plasma ion beam formation in the Advanced Plasma Source

    International Nuclear Information System (INIS)

    Harhausen, J; Foest, R; Hannemann, M; Ohl, A; Brinkmann, R P; Schröder, B

    2012-01-01

    The Advanced Plasma Source (APS) is employed for plasma ion-assisted deposition (PIAD) of optical coatings. The APS is a hot cathode dc glow discharge which emits a plasma ion beam to the deposition chamber at high vacuum (p ≲ 2 × 10 −4 mbar). It is established as an industrial tool but to date no detailed information is available on plasma parameters in the process chamber. As a consequence, the details of the generation of the plasma ion beam and the reasons for variations of the properties of the deposited films are barely understood. In this paper the results obtained from Langmuir probe and retarding field energy analyzer diagnostics operated in the plasma plume of the APS are presented, where the source was operated with argon. With increasing distance to the source exit the electron density (n e ) is found to drop by two orders of magnitude and the effective electron temperature (T e,eff ) drops by a factor of five. The parameters close to the source region read n e ≳ 10 11 cm −3 and T e,eff ≳ 10 eV. The electron distribution function exhibits a concave shape and can be described in the framework of the non-local approximation. It is revealed that an energetic ion population leaves the source region and a cold ion population in the plume is build up by charge exchange collisions with the background neutral gas. Based on the experimental data a scaling law for ion beam power is deduced, which links the control parameters of the source to the plasma parameters in the process chamber. (paper)

  5. Room temperature synthesis of porous SiO2 thin films by plasma enhanced chemical vapor deposition

    OpenAIRE

    Barranco Quero, Ángel; Cotrino Bautista, José; Yubero Valencia, Francisco; Espinós, J. P.; Rodríguez González-Elipe, Agustín

    2004-01-01

    Synthesis of porous SiO2 thin films in room temperature was carried out using plasma enhanced chemical vapor deposition (CVD) in an electron cyclotron resonance microwave reactor with a downstream configuration.The gas adsorption properties and the type of porosity of the SiO2 thin films were assessed by adsorption isotherms of toluene at room temperature.The method could also permit the tailoring synthesis of thin films when both composition and porosity can be simultaneously and independent...

  6. Deposition of controllable preferred orientation silicon films on glass by inductively coupled plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Li Junshuai; Wang Jinxiao; Yin Min; Gao Pingqi; He Deyan; Chen Qiang; Li Yali; Shirai, Hajime

    2008-01-01

    An inductively coupled plasma (ICP) system with the adjustable distance between the inductance coil and substrates was designed to effectively utilize the spatial confinement of ICP discharge, and then control the gas-phase transport process. The effects of the gas phase processes on the crystallinity and preferred orientation of silicon films deposited on glass were systematically investigated. The investigation was conducted in the ICP-chemical vapor deposition process with the precursor gas of a SiH 4 /H 2 mixture at a substrate temperature of 350 deg. Highly crystallized silicon films with different preferred orientations, (111) or (220), could be selectively deposited by adjusting the SiH 4 dilution ratio [R=[SiH 4 ]/([SiH 4 ]+[H 2 ])] or total working pressure. When the total working pressure is 20 Pa, the crystallinity of the silicon films increases with the increase of the SiH 4 dilution ratio, while the preferred orientation was changed from (111) to (220). In the case of the fixed SiH 4 dilution (10%), the silicon film with I (220) /I (111) of about 3.5 and Raman crystalline fraction of about 89.6% has been deposited at 29.7 nm/min when the total working pressure was increased to 40 Pa. At the fixed SiH 4 partial pressure of 2 Pa, the film crystallinity decreases and the preferred orientation is always (111) with increasing the H 2 partial pressure from 18 to 58 Pa. Atomic force microscope reveals that the film deposited at a relatively high H 2 partial pressure has a very rough surface caused by the devastating etching of H atoms to the silicon network

  7. Tribological properties of nitrogen-containing amorphous carbon film produced by dc plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Zhang Wei; Wazumi, Koichiro; Tanaka, Akihiro; Koga, Yoshinori

    2003-01-01

    The nitrogen-contained amorphous carbon (a-C:N) films were deposited in a dc plasma chemical vapor deposition system with different substrate bias voltages. The structural, mechanical, and tribological properties of the a-C:N films were investigated. The influence of the bias voltage on the tribological behaviors of the a-C:N films was evaluated under various environments (dry air, O 2 , N 2 , and vacuum) using a ball-on-disk friction tester. It showed that the sp 3 C and hydrogen concentration of the a-C:N films decreases with increasing the bias voltage. However, the nitrogen concentration increases with increasing the bias voltage. As a result, the hardness and internal stress decrease and the critical load for fracturing increases as the substrate bias increases. For the tribological properties of the a-C:N films, the friction coefficient of the films slightly decreases in the environments of N 2 , O 2 , or dry air, but increases slightly in the vacuum environment by increasing the bias voltage. It indicates that the incorporated nitrogen in the a-C:N films would decrease the friction coefficient of the films in N 2 or O 2 environments, but slightly increases the friction coefficient of the films in a vacuum. The excellent wear resistance of the a-C:N films, in the level of 10 -9 -10 -8 mm 3 /Nm, can be observed in N 2 , vacuum, and dry air environments. In addition, the effect of the bias voltage on the wear rate of the a-C:N films becomes less obvious by nitrogen incorporation. So, we suggest the incorporated nitrogen, which bonded to carbon and restrained the increase of the fraction of sp 2 C-C, would restrain the wear of the a-C:N films in different environments, especially in dry air

  8. Effects of pulse frequency of input power on the physical and chemical properties of pulsed streamer discharge plasmas in water

    Science.gov (United States)

    Ruma; Lukes, P.; Aoki, N.; Spetlikova, E.; Hosseini, S. H. R.; Sakugawa, T.; Akiyama, H.

    2013-03-01

    A repetitive pulsed-power modulator, which employs a magnetic pulse compression circuit with a high-speed thyristor switch, was used to study the effects of the pulse repetition rate of input power on the physical and chemical properties of pulsed discharges in water. Positive high-voltage pulses of 20 kV with repetition rates of up to 1 kHz were used to generate a discharge in water using the point-to-plane electrode geometry. By varying the pulse repetition rate, two distinct modes of the discharge plasma were formed in water. The first mode was characterized by the formation of a corona-like discharge propagating through water in the form of streamer channels. The second mode was formed typically above 500 Hz, when the formation of streamer channels in water was suppressed and all plasmas occurred inside a spheroidal aggregate of very fine gas bubbles surrounding the tip of the high-voltage electrode. The production of hydrogen peroxide, degradation of organic dye Acid Orange 7 (AO7) and inactivation of bacteria Escherichia coli by the discharge in water were studied under different discharge plasma modes in dependence on the pulse repetition rate of input power. The efficiency of both chemical and biocidal processes induced by the plasma in water decreased significantly with pulse repetition rates above 500 Hz.

  9. Effects of pulse frequency of input power on the physical and chemical properties of pulsed streamer discharge plasmas in water

    International Nuclear Information System (INIS)

    Ruma; Aoki, N; Hosseini, S H R; Sakugawa, T; Akiyama, H; Lukes, P; Spetlikova, E

    2013-01-01

    A repetitive pulsed-power modulator, which employs a magnetic pulse compression circuit with a high-speed thyristor switch, was used to study the effects of the pulse repetition rate of input power on the physical and chemical properties of pulsed discharges in water. Positive high-voltage pulses of 20 kV with repetition rates of up to 1 kHz were used to generate a discharge in water using the point-to-plane electrode geometry. By varying the pulse repetition rate, two distinct modes of the discharge plasma were formed in water. The first mode was characterized by the formation of a corona-like discharge propagating through water in the form of streamer channels. The second mode was formed typically above 500 Hz, when the formation of streamer channels in water was suppressed and all plasmas occurred inside a spheroidal aggregate of very fine gas bubbles surrounding the tip of the high-voltage electrode. The production of hydrogen peroxide, degradation of organic dye Acid Orange 7 (AO7) and inactivation of bacteria Escherichia coli by the discharge in water were studied under different discharge plasma modes in dependence on the pulse repetition rate of input power. The efficiency of both chemical and biocidal processes induced by the plasma in water decreased significantly with pulse repetition rates above 500 Hz. (paper)

  10. Chemical kinetics and relaxation of non-equilibrium air plasma generated by energetic photon and electron beams

    International Nuclear Information System (INIS)

    Maulois, Melissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Azaïs, Bruno

    2016-01-01

    The comprehension of electromagnetic perturbations of electronic devices, due to air plasma-induced electromagnetic field, requires a thorough study on air plasma. In the aim to understand the phenomena at the origin of the formation of non-equilibrium air plasma, we simulate, using a volume average chemical kinetics model (0D model), the time evolution of a non-equilibrium air plasma generated by an energetic X-ray flash. The simulation is undertaken in synthetic air (80% N_2 and 20% O_2) at ambient temperature and atmospheric pressure. When the X-ray flash crosses the gas, non-relativistic Compton electrons (low energy) and a relativistic Compton electron beam (high energy) are simultaneously generated and interact with the gas. The considered chemical kinetics scheme involves 26 influent species (electrons, positive ions, negative ions, and neutral atoms and molecules in their ground or metastable excited states) reacting following 164 selected reactions. The kinetics model describing the plasma chemistry was coupled to the conservation equation of the electron mean energy, in order to calculate at each time step of the non-equilibrium plasma evolution, the coefficients of reactions involving electrons while the energy of the heavy species (positive and negative ions and neutral atoms and molecules) is assumed remaining close to ambient temperature. It has been shown that it is the relativistic Compton electron beam directly created by the X-ray flash which is mainly responsible for the non-equilibrium plasma formation. Indeed, the low energy electrons (i.e., the non-relativistic ones) directly ejected from molecules by Compton collisions contribute to less than 1% on the creation of electrons in the plasma. In our simulation conditions, a non-equilibrium plasma with a low electron mean energy close to 1 eV and a concentration of charged species close to 10"1"3" cm"−"3 is formed a few nanoseconds after the peak of X-ray flash intensity. 200 ns after the

  11. Apparatus and method for enhanced chemical processing in high pressure and atmospheric plasmas produced by high frequency electromagnetic waves

    Science.gov (United States)

    Efthimion, Philip C.; Helfritch, Dennis J.

    1989-11-28

    An apparatus and method for creating high temperature plasmas for enhanced chemical processing of gaseous fluids, toxic chemicals, and the like, at a wide range of pressures, especially at atmospheric and high pressures includes an electro-magnetic resonator cavity, preferably a reentrant cavity, and a wave guiding structure which connects an electro-magnetic source to the cavity. The cavity includes an intake port and an exhaust port, each having apertures in the conductive walls of the cavity sufficient for the intake of the gaseous fluids and for the discharge of the processed gaseous fluids. The apertures are sufficiently small to prevent the leakage of the electro-magnetic radiation from the cavity. Gaseous fluid flowing from the direction of the electro-magnetic source through the guiding wave structure and into the cavity acts on the plasma to push it away from the guiding wave structure and the electro-magnetic source. The gaseous fluid flow confines the high temperature plasma inside the cavity and allows complete chemical processing of the gaseous fluids at a wide range of pressures.

  12. Effect of plasma composition on nanocrystalline diamond layers deposited by a microwave linear antenna plasma-enhanced chemical vapour deposition system

    Czech Academy of Sciences Publication Activity Database

    Taylor, Andrew; Ashcheulov, Petr; Čada, Martin; Fekete, Ladislav; Hubík, Pavel; Klimša, Ladislav; Olejníček, Jiří; Remeš, Zdeněk; Jirka, Ivan; Janíček, P.; Bedel-Pereira, E.; Kopeček, Jaromír; Mistrík, J.; Mortet, Vincent

    2015-01-01

    Roč. 212, č. 11 (2015), s. 2418-2423 ISSN 1862-6300 R&D Projects: GA ČR GA13-31783S; GA MŠk LO1409 Grant - others:FUNBIO(XE) CZ.2.16/3.1.00/21568 Institutional support: RVO:68378271 ; RVO:61388955 Keywords : diamond * electrical conductivity * nanocrystalline materials * optical emission spectroscopy * plasma enhanced chemical vapour deposition * SiC Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.648, year: 2015

  13. A new linear plasma device for various edge plasma studies at SWIP

    Science.gov (United States)

    Xu, Min; Zheng, Pengfei; Tynan, George; Che, Tong; Wang, Zhanhui; Guo, Dong; Wei, Ran

    2017-10-01

    To facilitate the plasma-material interactions (PMI) studies, Southwestern Institute of Physics (SWIP) has constructed a linear plasma device. It is comprised of a source chamber (Φ 0.4 m), a target chamber (Φ 0.9 m), 15 magnets with different sizes, and power supplies with the total power of a few hundred kilowatts, etc. A maximum magnetic field of 0.3 Tesla along the axial direction can be produced. The current of each of the 15 magnets can be independently controlled. More than 60 ports are available for diagnostics, with the sizes vary from Φ 50 mm to Φ 150 mm. Rectangular ports of 190 mm × 270 mm are also available. 12 ports looking at the sample holder are specially designed for ion beam injection, of which the axes are 25 to the chamber axis. The device is equipped with a LaB6 hot cathode plasma source, which is able to generate steady-state H/D/He plasmas with a diameter of Φ 100 mm, density of 1x1019 /m3 , and a particle flux of 1022 1023 n/m2 .s. The electron temperature is usually a few eV. Further, a Helicon RF plasma source is also planned for plasma transport studies. Int'l Sci & Tech Cooperation Program of China (No. 2015DFA61760).

  14. The Influences of H2Plasma Pretreatment on the Growth of Vertically Aligned Carbon Nanotubes by Microwave Plasma Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Wen Hua-Chiang

    2008-01-01

    Full Text Available AbstractThe effects of H2flow rate during plasma pretreatment on synthesizing the multiwalled carbon nanotubes (MWCNTs by using the microwave plasma chemical vapor deposition are investigated in this study. A H2and CH4gas mixture with a 9:1 ratio was used as a precursor for the synthesis of MWCNT on Ni-coated TaN/Si(100 substrates. The structure and composition of Ni catalyst nanoparticles were investigated using scanning electron microscopy (SEM and transmission electron microscopy (TEM. The present findings showed that denser Ni catalyst nanoparticles and more vertically aligned MWCNTs could be effectively achieved at higher flow rates. From Raman results, we found that the intensity ratio of G and D bands (ID/IG decreases with an increasing flow rate. In addition, TEM results suggest that H2plasma pretreatment can effectively reduce the amorphous carbon and carbonaceous particles. As a result, the pretreatment plays a crucial role in modifying the obtained MWCNTs structures.

  15. Gravimetrical and chemical characterization of SiOx structures deposited on fine powders by short plasma exposure in a plasma down stream reactor

    International Nuclear Information System (INIS)

    Spillmann, Adrian; Sonnenfeld, Axel; Rohr, Philipp Rudolf von

    2008-01-01

    The surface of lactose particles was modified by a plasma-enhanced chemical vapor deposition process to improve the flow behavior of the powder. For this, the particulates were treated in a plasma down stream reactor which provides a short (50 ms) and homogeneous exposure to the capacitively coupled RF discharge. The organosilicon monomer hexamethyldisiloxane (HMDSO) was used as a precursor for the formation of SiO x which is deposited on the substrate particle surface. For varying process gas mixtures (O 2 /Ar/HMDSO) and RF power applied, the amount of the deposited material was determined gravimetrically after dissolution of the lactose substrate particles and the chemical composition of the accumulated deposition material was investigated by means of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The concentration of the deposited SiO x relating to the substrate material was found to be in the range of 0.1 wt.%. Based on the ATR-FTIR analysis, the inorganic, i.e. oxidic SiO x fraction of the obtained deposits was shown to be controllable by varying the process parameters, whilst a relatively large amount of organic structures must be considered.

  16. Physical and chemical contributions of a plasma treatment in the growth of ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Jang, J.T. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, H., E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, W.J. [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of); Yun, J. [Department of Nano Science and Engineering, Kyungnam University, Changwon, Gyeongnam 631-701 (Korea, Republic of)

    2013-11-15

    Highlights: •ZnO nanorods were grown by hydrothermal synthesis. •Oxygen plasma was done on the surface of seed ZnO nanorods. •The ZnO nanorods with and without plasma treatment were characterized. •The results showed that the optical and structural properties of ZnO nanorods with plasma treatment were enhanced. -- Abstract: We analyzed the enhancement of optical and structural properties of ZnO nanorods by using a plasma treatment. In this study, seed ZnO nanorods were grown by hydrothermal synthesis for 1 h on a ZnO buffered Si substrate. The seed ZnO nanorods were then treated with an oxygen plasma. Next, ZnO was grown for an additional 4 h by hydrothermal synthesis. The resultant ZnO nanorods were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD) and photoluminescence (PL). The measurements showed that the plasma treatment of the seed ZnO nanorods increased the roughness of the buffer layer and the concentration of oxygen ions on the surfaces of the seed ZnO nanorods and the buffer layer, leading to improved optical and structural properties. In this study, we found that the plasma treatment on the seed ZnO nanorods enhanced the optical and structural properties of the ZnO nanorods.

  17. Plasma-chemical modification of the structure and properties of poly(ethylene terephthalate) track membranes

    International Nuclear Information System (INIS)

    Kravets, L I; Dmitriev, S N; Dinescu, G; Lazea, A; Sleptsov, V V; Elinson, V M

    2007-01-01

    A process of extraction of the low-molecular products of the synthesis from the poly(ethylene terephthalate) track membranes modified by plasma has been investigated. It is shown that the deposition of a thin polymeric hydrocarbon film by cyclohexane plasma on the membrane surface with preliminary treatment in a plasma of non-polymerizing gases, for example oxygen, allows one to produce membranes possessing a high productivity. Their advantages are much better hydrodynamic properties and a small amount of the low-molecular products of the synthesis extracted by organic solvents

  18. Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

    Science.gov (United States)

    Moraczewski, Krzysztof; Rytlewski, Piotr; Malinowski, Rafał; Żenkiewicz, Marian

    2015-08-01

    The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm2 was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

  19. Physico-chemical characteristics of high performance polymer modified by low and atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Bhatnagar, Nitu; Sangeeta, Jha; Bhowmik, Shantanu; Gupta, Govind; Moon, J.B.; Kim, C.G.

    2012-01-01

    In this work, the effect of low pressure plasma and atmospheric p ressure plasma treatment on surface properties and adhesion characteristics of high performance polymer, Polyether Ether Ketone (PEEK) are investigated in terms of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Atomic Force Microscopy (AFM). The experimental results show that the PEEK surface treated by atmospheric pressure plasma lead to an increase in the polar component of the surface energy, resulting in improving the adhesion characteristics of the PEEK/Epoxy adhesive system. Also, the roughness of the treated surfaces is largely increased as confirmed by AFM observation. These results can be explained by the fact that the atmospheric pressure plasma treatment of PEEK surface yields several oxygen functionalities on hydrophobic surface, which play an important role in increasing the surface polarity, wettability, and the adhesion characteristics of the PEEK/Epoxy adhesive system. (authors)

  20. Chemical compositions of spherical titanium powders prepared by RF induction plasma

    International Nuclear Information System (INIS)

    Gu Zhongtao; Jin Yuping; Ye Gaoying

    2012-01-01

    Spherical titanium powders were prepared by RF induction plasma technology. The particle size is essentially un- changed, while the particle size distribution is relatively narrow after spheroidization processing. X-ray diffraction (XRD) random testing of the spherical titanium powders shows no structure and phase changes. The content of O, H, N and C decreases, while the content of Ti increases slightly. It indicates that spheroidization with RF plasma can enhance powder purity. (authors)

  1. CH spectroscopy for carbon chemical erosion analysis in high density low temperature hydrogen plasma

    NARCIS (Netherlands)

    Westerhout, J.; Cardozo, N. J. L.; Rapp, J.; van Rooij, G. J.

    2009-01-01

    The CH A-X molecular band is measured upon seeding the hydrogen plasma in the linear plasma generator Pilot-PSI [electron temperature T-e=0.1-2.5 eV and electron density n(e)=(0.5-5) X 10(20) m(-3)] with methane. Calculated inverse photon efficiencies for these conditions range from 3 up to

  2. Effects of molecular size and chemical factor on plasma gene transfection

    Science.gov (United States)

    Ikeda, Yoshihisa; Motomura, Hideki; Kido, Yugo; Satoh, Susumu; Jinno, Masafumi

    2016-07-01

    In order to clarify the mechanism of plasma gene transfection, the relationship between transfection efficiency and transferred molecular size was investigated. Molecules with low molecular mass (less than 50 kDa; dye or dye-labeled oligonucleotide) and high molecular mass (more than 1 MDa; plasmid DNA or fragment of plasmid DNA) were transferred to L-929 cells. It was found that the transfection efficiency decreases with increasing in transferred molecular size and also depends on the tertiary structure of transferred molecules. Moreover, it was suggested the transfection mechanism is different between the molecules with low (less than 50 kDa) and high molecular mass (higher than 1 MDa). For the amount of gene transfection after plasma irradiation, which is comparable to that during plasma irradiation, it is shown that H2O2 molecules are the main contributor. The transfection efficiency decreased to 0.40 ± 0.22 upon scavenging the H2O2 generated by plasma irradiation using the catalase. On the other hand, when the H2O2 solution is dropped into the cell suspension without plasma irradiation, the transfection efficiency is almost 0%. In these results, it is also suggested that there is a synergetic effect of H2O2 with electrical factors or other reactive species generated by plasma irradiation.

  3. The component content of active particles in a plasma-chemical reactor based on volume barrier discharge

    Science.gov (United States)

    Soloshenko, I. A.; Tsiolko, V. V.; Pogulay, S. S.; Terent'yeva, A. G.; Bazhenov, V. Yu; Shchedrin, A. I.; Ryabtsev, A. V.; Kuzmichev, A. I.

    2007-02-01

    In this paper the results of theoretical and experimental studies of the component content of active particles formed in a plasma-chemical reactor composed of a multiple-cell generator of active particles, based on volume barrier discharge, and a working chamber are presented. For calculation of the content of uncharged plasma components an approach is proposed which is based on averaging of the power introduced over the entire volume. Advantages of such an approach lie in an absence of fitting parameters, such as the dimensions of microdischarges, their surface density and rate of breakdown. The calculation and the experiment were accomplished with the use of dry air (20% relative humidity) as the plasma generating medium. Concentrations of O3, HNO3, HNO2, N2 O5 and NO3 were measured experimentally in the discharge volume and working chamber for the residence time of particles on a discharge of 0.3 s and more and discharge specific power of 1.5 W cm-3. It has been determined that the best agreement between the calculation and the experiment occurs at calculated gas medium temperatures in the discharge plasma of about 400-425 K, which correspond to the experimentally measured rotational temperature of nitrogen. In most cases the calculated concentrations of O3, HNO3, HNO2, N2O5 and NO3 for the barrier discharge and the working chamber are in fairly good agreement with the respective measured values.

  4. Low-Pressure H2, NH3 Microwave Plasma Treatment of Polytetrafluoroethylene (PTFE) Powders: Chemical, Thermal and Wettability Analysis

    Science.gov (United States)

    Hunke, Harald; Soin, Navneet; Shah, Tahir H.; Kramer, Erich; Pascual, Alfons; Karuna, Mallampalli Sri Lakshmi; Siores, Elias

    2015-01-01

    Functionalization of Polytetrafluoroethylene (PTFE) powders of ~6 μm particle size is carried out using low-pressure 2.45 GHz H2, NH3 microwave plasmas for various durations (2.5, 10 h) to chemically modify their surface and alter their surface energy. The X-ray Photoelectron Spectroscopy (XPS) analyses reveal that plasma treatment leads to significant defluorination (F/C atomic ratio of 1.13 and 1.30 for 10 h NH3 and H2 plasma treatments, respectively vs. 1.86 for pristine PTFE), along with the incorporation of functional polar moieties on the surface, resulting in enhanced wettability. Analysis of temperature dependent XPS revealed a loss of surface moieties above 200 °C, however, the functional groups are not completely removable even at higher temperatures (>300 °C), thus enabling the use of plasma treated PTFE powders as potential tribological fillers in high temperature engineering polymers. Ageing studies carried over a period of 12 months revealed that while the surface changes degenerate over time, again, they are not completely reversible. These functionalised PTFE powders can be further used for applications into smart, high performance materials such as tribological fillers for engineering polymers and bio-medical, bio-material applications.

  5. The component content of active particles in a plasma-chemical reactor based on volume barrier discharge

    International Nuclear Information System (INIS)

    Soloshenko, I A; Tsiolko, V V; Pogulay, S S; Terent'yeva, A G; Bazhenov, V Yu; Shchedrin, A I; Ryabtsev, A V; Kuzmichev, A I

    2007-01-01

    In this paper the results of theoretical and experimental studies of the component content of active particles formed in a plasma-chemical reactor composed of a multiple-cell generator of active particles, based on volume barrier discharge, and a working chamber are presented. For calculation of the content of uncharged plasma components an approach is proposed which is based on averaging of the power introduced over the entire volume. Advantages of such an approach lie in an absence of fitting parameters, such as the dimensions of microdischarges, their surface density and rate of breakdown. The calculation and the experiment were accomplished with the use of dry air (20% relative humidity) as the plasma generating medium. Concentrations of O 3 , HNO 3 , HNO 2 , N 2 O 5 and NO 3 were measured experimentally in the discharge volume and working chamber for the residence time of particles on a discharge of 0.3 s and more and discharge specific power of 1.5 W cm -3 . It has been determined that the best agreement between the calculation and the experiment occurs at calculated gas medium temperatures in the discharge plasma of about 400-425 K, which correspond to the experimentally measured rotational temperature of nitrogen. In most cases the calculated concentrations of O 3 , HNO 3 , HNO 2 , N 2 O 5 and NO 3 for the barrier discharge and the working chamber are in fairly good agreement with the respective measured values

  6. Gene expression responses of HeLa cells to chemical species generated by an atmospheric plasma flow

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Mayo, E-mail: yokoyama@plasma.ifs.tohoku.ac.jp [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Johkura, Kohei, E-mail: kohei@shinshu-u.ac.jp [Department of Histology and Embryology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621 (Japan); Sato, Takehiko, E-mail: sato@ifs.tohoku.ac.jp [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2014-08-08

    Highlights: • Response of HeLa cells to a plasma-irradiated medium was revealed by DNA microarray. • Gene expression pattern was basically different from that in a H{sub 2}O{sub 2}-added medium. • Prominently up-/down-regulated genes were partly shared by the two media. • Gene ontology analysis showed both similar and different responses in the two media. • Candidate genes involved in response to ROS were detected in each medium. - Abstract: Plasma irradiation generates many factors able to affect the cellular condition, and this feature has been studied for its application in the field of medicine. We previously reported that hydrogen peroxide (H{sub 2}O{sub 2}) was the major cause of HeLa cell death among the chemical species generated by high level irradiation of a culture medium by atmospheric plasma. To assess the effect of plasma-induced factors on the response of live cells, HeLa cells were exposed to a medium irradiated by a non-lethal plasma flow level, and their gene expression was broadly analyzed by DNA microarray in comparison with that in a corresponding concentration of 51 μM H{sub 2}O{sub 2}. As a result, though the cell viability was sufficiently maintained at more than 90% in both cases, the plasma-medium had a greater impact on it than the H{sub 2}O{sub 2}-medium. Hierarchical clustering analysis revealed fundamentally different cellular responses between these two media. A larger population of genes was upregulated in the plasma-medium, whereas genes were downregulated in the H{sub 2}O{sub 2}-medium. However, a part of the genes that showed prominent differential expression was shared by them, including an immediate early gene ID2. In gene ontology analysis of upregulated genes, the plasma-medium showed more diverse ontologies than the H{sub 2}O{sub 2}-medium, whereas ontologies such as “response to stimulus” were common, and several genes corresponded to “response to reactive oxygen species.” Genes of AP-1 proteins, e.g., JUN

  7. Bio-compatibility, surface and chemical characterization of glow discharge plasma modified ZnO nanocomposite polycarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Bagra, Bhawna, E-mail: bhawnacct@gmail.com; Pimpliskar, Prashant, E-mail: bhawnacct@gmail.com [Centre for Converging Technologies, University of Rajasthan, Jaipur-302004 (India); Agrawal, Narendra Kumar [Department of Physics, Malaviya National Institute of Technology, Jaipur-302004 (India)

    2014-04-24

    Bio compatibility is an important issue for synthesis of biomedical devices, which can be tested by bioadoptability and creations of active site to enhance the bacterial/cell growth in biomedical devices. Hence a systematic study was carried out to characterize the effects of Nitrogen ion plasma for creations of active site in nano composite polymer membrane. Nano particles of ZnO are synthesized by chemical root, using solution casting nano composite polymeric membranes were prepared and treated with Nitrogen ion plasma. These membranes were characterized by different technique such as optical microscopy, SEM- Scanning electron microscope, optical transmittance, Fourier transform infrared spectroscopy. Then biocompatibility for membranes was tested by testing of bio-adoptability of membrane.

  8. Characteristics of Ge-Sb-Te films prepared by cyclic pulsed plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Suk, Kyung-Suk; Jung, Ha-Na; Woo, Hee-Gweon; Park, Don-Hee; Kim, Do-Heyoung

    2010-05-01

    Ge-Sb-Te (GST) thin films were deposited on TiN, SiO2, and Si substrates by cyclic-pulsed plasma-enhanced chemical vapor deposition (PECVD) using Ge{N(CH3)(C2H5)}, Sb(C3H7)3, Te(C3H7)3 as precursors in a vertical flow reactor. Plasma activated H2 was used as the reducing agent. The growth behavior was strongly dependent on the type of substrate. GST grew as a continuous film on TiN regardless of the substrate temperature. However, GST formed only small crystalline aggregates on Si and SiO2 substrates, not a continuous film, at substrate temperatures > or = 200 degrees C. The effects of the deposition temperature on the surface morphology, roughness, resistivity, crystallinity, and composition of the GST films were examined.

  9. Nanostructure and optical properties of CeO{sub 2} thin films obtained by plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Barreca, D.; Bruno, G.; Gasparotto, A.; Losurdo, M.; Tondello, E

    2003-12-15

    In the present study, Spectroscopic Ellipsometry (SE) is used to investigate the interrelations between nanostructure and optical properties of CeO{sub 2} thin films deposited by Plasma-Enhanced Chemical Vapor Deposition (PE-CVD). The layers were synthesized in Ar and Ar-O{sub 2} plasmas on Si(100) substrates at temperatures lower than 300 deg. C. Both the real and imaginary parts of the complex dielectric functions and, subsequently, the optical constants of the films are derived up to 6.0 eV photon energy. Particular attention is devoted to the influence of synthesis conditions and sample properties on the optical response, taking into account the effects of surface roughness and SiO{sub 2} interface layer on Si.

  10. Sticking non-stick: Surface and Structure control of Diamond-like Carbon in Plasma Enhanced Chemical Vapour Deposition

    Science.gov (United States)

    Jones, B. J.; Nelson, N.

    2016-10-01

    This short review article explores the practical use of diamond-like carbon (DLC) produced by plasma enhanced chemical vapour deposition (PECVD). Using as an example issues relating to the DLC coating of a hand-held surgical device, we draw on previous works using atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, tensiometry and electron paramagnetic resonance. Utilising data from these techniques, we examine the surface structure, substrate-film interface and thin film microstructure, such as sp2/sp3 ratio (graphitic/diamond-like bonding ratio) and sp2 clustering. We explore the variations in parameters describing these characteristics, and relate these to the final device properties such as friction, wear resistance, and diffusion barrier integrity. The material and device characteristics are linked to the initial plasma and substrate conditions.

  11. Sticking non-stick: Surface and Structure control of Diamond-like Carbon in Plasma Enhanced Chemical Vapour Deposition

    International Nuclear Information System (INIS)

    Jones, B J; Nelson, N

    2016-01-01

    This short review article explores the practical use of diamond-like carbon (DLC) produced by plasma enhanced chemical vapour deposition (PECVD). Using as an example issues relating to the DLC coating of a hand-held surgical device, we draw on previous works using atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, tensiometry and electron paramagnetic resonance. Utilising data from these techniques, we examine the surface structure, substrate-film interface and thin film microstructure, such as sp 2 /sp 3 ratio (graphitic/diamond-like bonding ratio) and sp 2 clustering. We explore the variations in parameters describing these characteristics, and relate these to the final device properties such as friction, wear resistance, and diffusion barrier integrity. The material and device characteristics are linked to the initial plasma and substrate conditions. (paper)

  12. LiF enhanced nucleation of the low temperature microcrystalline silicon prepared by plasma enhanced chemical vapour deposition

    Czech Academy of Sciences Publication Activity Database

    Stuchlík, Jiří; Ledinský, Martin; Honda, Shinya; Drbohlav, Ivo; Mates, Tomáš; Fejfar, Antonín; Hruška, Karel; Stuchlíková, The-Ha; Kočka, Jan

    2009-01-01

    Roč. 517, č. 24 (2009), s. 6829-6832 ISSN 0040-6090 R&D Projects: GA AV ČR KAN400100701; GA ČR(CZ) GD202/05/H003; GA MŠk LC510; GA AV ČR IAA1010413 Institutional research plan: CEZ:AV0Z10100521 Keywords : amorphous hydrogenated silicon * atomic force microscopy * plasma-enhanced chemical vapour deposition, * nucleation * Raman scattering * lithium fluoride Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.727, year: 2009

  13. Physical-morphological and chemical changes leading to an increase in adhesion between plasma treated polyester fibres and a rubber matrix

    International Nuclear Information System (INIS)

    Krump, H.; Hudec, I.; Jasso, M.; Dayss, E.; Luyt, A.S.

    2006-01-01

    The effects of plasma treatment, used to increase adhesion strength between poly(ethylene terephtalate) (PET) fibres and a rubber matrix, were investigated and compared. Morphological changes as a result of atmospheric plasma treatment were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Wettability analysis using a surface energy evaluation system (SEE system) suggested that the plasma treated fibre was more wetting towards a polar liquid. When treated, these fibres showed a new lamellar crystallization, as shown by a new melting peak using differential scanning calorimetry (DSC). X-ray photoelectron spectroscopy (XPS) has been used to study the chemical effect of inert (argon), active and reactive (nitrogen and oxygen) microwave-plasma treatments of a PET surface. Reactive oxygen plasma treatment by a de-convolution method shows new chemical species that drastically alter the chemical reactivity of the PET surface. These studies have also shown that the surface population of chemical species formed after microwave-plasma treatment is dependent on the plasma gas. All these changes cause better adhesion strength of the PET fibres to the rubber matrix

  14. Simulation of two-dimensional interior ballistics model of solid propellant electrothermal-chemical launch with discharge rod plasma generator

    Directory of Open Access Journals (Sweden)

    Yan-jie Ni

    2017-08-01

    Full Text Available Instead of the capillary plasma generator (CPG, a discharge rod plasma generator (DRPG is used in the 30 mm electrothermal-chemical (ETC gun to improve the ignition uniformity of the solid propellant. An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun (2D-IB-SPETCG is presented to describe the process of the ETC launch. Both calculated pressure and projectile muzzle velocity accord well with the experimental results. The feasibility of the 2D-IB-SPETCG model is proved. Depending on the experimental data and initial parameters, detailed distribution of the ballistics parameters can be simulated. With the distribution of pressure and temperature of the gas phase and the propellant, the influence of plasma during the ignition process can be analyzed. Because of the radial flowing plasma, the propellant in the area of the DRPG is ignited within 0.01 ms, while all propellant in the chamber is ignited within 0.09 ms. The radial ignition delay time is much less than the axial delay time. During the ignition process, the radial pressure difference is less than 5  MPa at the place 0.025 m away from the breech. The radial ignition uniformity is proved. The temperature of the gas increases from several thousand K (conventional ignition to several ten thousand K (plasma ignition. Compare the distribution of the density and temperature of the gas, we know that low density and high temperature gas appears near the exits of the DRPG, while high density and low temperature gas appears at the wall near the breech. The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch. The 2D-IB-SPETC model can be used for prediction and improvement of experiments.

  15. Chemical Vapor Identification by Plasma Treated Thick Film Tin Oxide Gas Sensor Array and Pattern Recognition

    Directory of Open Access Journals (Sweden)

    J. K. Srivastava

    2011-02-01

    Full Text Available Present study deals the class recognition potential of a four element plasma treated thick film tin oxide gas sensor array exposed with volatile organic compounds (VOCs. Methanol, Ethanol and Acetone are selected as target VOCs and exposed on sensor array at different concentration in range from 100-1000 ppm. Sensor array consist of four tin oxide sensors doped with 1-4 % PbO concentrations were fabricated by thick film technology and then treated with oxygen plasma for 5-10 minute durations. Sensor signal is analyzed by principal component analysis (PCA for visual classification of VOCs. Further output of PCA is used as input for classification of VOCs by four pattern classification techniques as: linear discriminant analysis (LDA, k-nearest neighbor (KNN, back propagation neural network (BPNN and support vector machine (SVM. All the four classifier results 100 % correct classification rate of VOCs by response analysis of sensor array treated with plasma for 5 minute.

  16. Role of chlorine in the nanocrystalline silicon film formation by rf plasma-enhanced chemical vapor deposition of chlorinated materials

    International Nuclear Information System (INIS)

    Shirai, Hajime

    2004-01-01

    We demonstrate the disorder-induced low-temperature crystallization in the nanocrystalline silicon film growth by rf plasma-enhanced chemical vapor deposition of H 2 -diluted SiH 2 Cl 2 and SiCl 4 . The combination of the chemical reactivity of SiCld (d: dangling bond) and SiHCl complexes and the release of the disorder-induced stress near the growing surface tightly correlate with the phase transitionity of SiCld and SiHCl complexes near the growing surface with the aid of atomic hydrogen, which induce higher degree of disorder in the a-Si network. These features are most prominent in the SiCl 4 compared with those of SiH 2 Cl 2 and SiH 4 , which preferentially enhance the nanocrystalline Si formation

  17. Grafting of copolymer styrene maleic anhydride on poly(ethylene terephthalate) film by chemical reaction and by plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Bigan, Muriel; Bigot, Julien [Laboratoire de Chimie Organique et Macromoleculaire (UMR 8009), Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Mutel, Brigitte [Laboratoire de Genie des Procedes d' Interactions Fluides reactifs-Materiaux (UPRES-EA 3751), Batiment C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France)], E-mail: Brigitte.mutel@univ-lille1.fr; Coqueret, Xavier [Laboratoire Reactions Selectives et Applications (UMR-CNRS 6519) Universite de Reims Champagne-Ardennes, B.P. 1039, 51687 Reims Cedex 2 (France)

    2008-02-15

    This work deals with the chemical grafting of a styrene maleic anhydride copolymer on the surface of a previously hydrolyzed polyethylene terephthalate (PET) film 12 {mu}m thick via covalent bond. Two different ways are studied. The first one involves an activation of the hydrolyzed PET by the triethylamine before the grafting step. In the second one, the copolymer reacts with the 4-dimethylaminopyridine in order to form maleinyl pyridinium salt which reacts with alcohol function of the hydrolyzed PET. Characterization and quantification of the grafting are performed by Fourier transform infrared spectroscopy. Factorial experiment designs are used to optimize the process and to estimate experimental parameters effects. The opportunity to associate the chemical process to a cold remote nitrogen plasma one is also examined.

  18. Resolving the nanostructure of plasma-enhanced chemical vapor deposited nanocrystalline SiOx layers for application in solar cells

    Science.gov (United States)

    Klingsporn, M.; Kirner, S.; Villringer, C.; Abou-Ras, D.; Costina, I.; Lehmann, M.; Stannowski, B.

    2016-06-01

    Nanocrystalline silicon suboxides (nc-SiOx) have attracted attention during the past years for the use in thin-film silicon solar cells. We investigated the relationships between the nanostructure as well as the chemical, electrical, and optical properties of phosphorous, doped, nc-SiO0.8:H fabricated by plasma-enhanced chemical vapor deposition. The nanostructure was varied through the sample series by changing the deposition pressure from 533 to 1067 Pa. The samples were then characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, Raman spectroscopy, aberration-corrected high-resolution transmission electron microscopy, selected-area electron diffraction, and a specialized plasmon imaging method. We found that the material changed with increasing pressure from predominantly amorphous silicon monoxide to silicon dioxide containing nanocrystalline silicon. The nanostructure changed from amorphous silicon filaments to nanocrystalline silicon filaments, which were found to cause anisotropic electron transport.

  19. Study of plasma-chemical NO-containing gas flow for treatment of wounds and inflammatory processes.

    Science.gov (United States)

    Pekshev, Alexander V; Shekhter, Anatoly B; Vagapov, Andrey B; Sharapov, Nikolay A; Vanin, Anatoly F

    2018-02-28

    This work is aimed at exhaustive and detailed study of chemical, physical and physico-chemical characteristics of NO-containing gas flow (NO-CGF) generated by a plasma-chemical generator of Plason device, which has been used in medical practice for more than 15 years for effectively healing wound and inflammatory conditions with exogenous nitric oxide (NO-therapy). Data was obtained on spatial structure of the gas flow, and values of its local parameters in axial and radial directions, such as nitric oxide content, velocity, temperature and mass flow density of nitric oxide, providing altogether the effectiveness of treatment by the exogenous NO-therapy method, were determined experimentally and by computations. It was demonstrated that plasma-chemical synthesis of NO from atmospheric air in a low direct current (DC) arc provides a high mass flow of nitric oxide at the level of 1.6-1.8 mg/s, while in the area of impact of NO-CGF on the biological tissue, on its axis, NO content is 400-600 ppm, flow velocity about 5 m/s, nitric oxide mass flow density 0.25-0.40 mg/(s·cm 2 ), temperature 40-60 °C. Tendencies were determined for designing new devices for further experimental biological and medical research in the field of NO-therapy: lowering the temperature of NO-CGF to ambient temperature will enable variation, in experiments, of the affecting flow parameters in a wide range up to their maximum values: NO content up to 2000 ppm, velocity up to 20 m/s, nitric oxide mass flow density up to 2.5 mg/(s·cm 2 ). Copyright © 2017. Published by Elsevier Inc.

  20. The calculation of electron chemical potential and ion charge state and their influence on plasma conductivity in electrical explosion of metal wire

    International Nuclear Information System (INIS)

    Shi, Zongqian; Wang, Kun; Li, Yao; Shi, Yuanjie; Wu, Jian; Jia, Shenli

    2014-01-01

    The electron chemical potential and ion charge state (average ion charge and ion distribution) are important parameters in calculating plasma conductivity in electrical explosion of metal wire. In this paper, the calculating method of electron chemical potential and ion charge state is discussed at first. For the calculation of electron chemical potential, the ideal free electron gas model and Thomas-Fermi model are compared and analyzed in terms of the coupling constant of plasma. The Thomas-Fermi ionization model, which is used to calculate ion charge state, is compared with the method based on Saha equation. Furthermore, the influence of electron degenerated energy levels and ion excited states in Saha equation on the ion charge state is also analyzed. Then the influence of different calculating methods of electron chemical potential and ion charge state on plasma conductivity is discussed by applying them in the Lee-More conductivity model

  1. Heteroepitaxial Growth of Germanium-on-Silicon Using Ultrahigh-Vacuum Chemical Vapor Deposition with RF Plasma Enhancement

    Science.gov (United States)

    Alharthi, Bader; Grant, Joshua M.; Dou, Wei; Grant, Perry C.; Mosleh, Aboozar; Du, Wei; Mortazavi, Mansour; Li, Baohua; Naseem, Hameed; Yu, Shui-Qing

    2018-05-01

    Germanium (Ge) films have been grown on silicon (Si) substrate by ultrahigh-vacuum chemical vapor deposition with plasma enhancement (PE). Argon plasma was generated using high-power radiofrequency (50 W) to assist in germane decomposition at low temperature. The growth temperature was varied in the low range of 250°C to 450°C to make this growth process compatible with complementary metal-oxide-semiconductor technology. The material and optical properties of the grown Ge films were investigated. The material quality was determined by Raman and x-ray diffraction techniques, revealing growth of crystalline films in the temperature range of 350°C to 450°C. Photoluminescence spectra revealed improved optical quality at growth temperatures of 400°C and 450°C. Furthermore, material quality study using transmission electron microscopy revealed existence of defects in the Ge layer grown at 400°C. Based on the etch pit density, the average threading dislocation density in the Ge layer obtained at this growth temperature was measured to be 4.5 × 108 cm-2. This result was achieved without any material improvement steps such as use of graded buffer or thermal annealing. Comparison between PE and non-plasma-enhanced growth, in the same machine at otherwise the same growth conditions, indicated increased growth rate and improved material and optical qualities for PE growth.

  2. Plasma-assisted partial oxidation of methane at low temperatures: numerical analysis of gas-phase chemical mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Goujard, Valentin; Nozaki, Tomohiro; Yuzawa, Shuhei; Okazaki, Ken [Department of Mechanical and Control Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, 1528552, Tokyo (Japan); Agiral, Anil, E-mail: tnozaki@mech.titech.ac.jp [Mesoscale Chemical Systems, MESA Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, PO Box 217, 7500 AE, Enschede (Netherlands)

    2011-07-13

    Methane partial oxidation was investigated using a plasma microreactor. The experiments were performed at 5 and 300 deg. C. Microreactor configuration allows an efficient evacuation of the heat generated by methane partial oxidation and dielectric barrier discharges, allowing at the same time a better temperature control. At 5 deg. C, liquid condensation of low vapour pressure compounds, such as formaldehyde and methanol, occurs. {sup 1}H-NMR analysis allowed us to demonstrate significant CH{sub 3}OOH formation during plasma-assisted partial oxidation of methane. Conversion and product selectivity were discussed for both temperatures. In the second part of this work, a numerical simulation was performed and a gas-phase chemical mechanism was proposed and discussed. From the comparison between the experimental results and the simulation it was found that CH{sub 3}OO{center_dot} formation has a determinant role in oxygenated compound production, since its fast formation disfavoured radical recombination. At 5 deg. C the oxidation leads mainly towards oxygenated compound formation, and plasma dissociation was the major phenomenon responsible for CH{sub 4} conversion. At 300 deg. C, higher CH{sub 4} conversion resulted from oxidative reactions induced by {center_dot}OH radicals with a chemistry predominantly oxidative, producing CO, H{sub 2}, CO{sub 2} and H{sub 2}O.

  3. Chemical fate of the nicotinic acetylcholinergic radiotracer [123I]5-IA-85380 in baboon brain and plasma

    International Nuclear Information System (INIS)

    Baldwin, Ronald M.; Zoghbi, Sami S.; Staley, Julie K.; Brenner, Eric; Al-Tikriti, Mohammed S.; Amici, Louis; Fujita, Masahiro; Innis, Robert B.; Tamagnan, Gilles

    2006-01-01

    The fate of the nicotinic acetylcholinergic receptor radiotracer [ 123 I]5-IA-85380 ([ 123 I]5-IA) was studied in baboon by analyzing the chemical composition of brain tissue and plasma after intravenous administration of the tracer. Acetonitrile denaturation and high-performance liquid chromatography (HPLC) analysis showed predominantly unchanged (91-98%) parent tracer in all brain tissues examined, compared to significant metabolism (23% parent) in the plasma at 90 min postinjection, and control tissue recovery of 95-98%. [ 123 I]5-IA was distributed to the thalamus with a standardized uptake value of 9.2 (0.04% dose/g) or a concentration 5.8 times higher than that of the cerebellum. The HPLC behavior of a synthesized sample of one hypothesized metabolite, 5-iodo-3-pyridinol (5-IP), was consistent with plasma radiometabolite fraction. Since only parent radiotracer compound was found in brain tissue, these results add confidence that information derived from single photon emission computed tomography images of 123 I activity in the brain after [ 123 I]5-IA administration can be interpreted as distribution of an intact radiotracer

  4. Modification of optical and electrical properties of chemical bath deposited SnS using O{sub 2} plasma treatments

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, A. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Martínez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Calixto-Rodríguez, M. [Centro de Investigación en Energía, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Avellaneda, D. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, México (Mexico); Reyes, P.G. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Flores, O. [Instituto de Ciencias Fisicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico)

    2013-06-15

    In this paper, we report modifications of structural and optical, electrical properties that occur in tin sulphide (SnS) treated in O{sub 2} plasma. The SnS thin films were deposited by chemical bath deposition technique. The samples were treated in an O{sub 2} plasma discharge at 3 Torr of pressure discharge, a discharge voltage of 2.5 kV and 20 mA of discharge current. The prepared and treated thin films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The photoconductivity and electrical effects of SnS have been studied. The SnS thin films had an orthorhombic crystalline structure. With the plasma treatment the optical gap and electrical properties of the SnS films changed from 1.61 to 1.84 eV, for 3.9 × 10{sup 5} to 10.42 Ω cm, respectively. These changes can be attributed to an increase in electron density, percolation effects due to porosity, surface degradation/etching that is an increase in surface roughness, where some structural changes related to crystallinity occurs like a high grain size as revealed by SEM images.

  5. Properties of plasma assisted chemical vapor deposited coatings of titanium boride on Ti--6Al--4V alloy substrates

    International Nuclear Information System (INIS)

    Otter, F.A.; Amisola, G.B.; Roman, W.C.; Hay, S.O.

    1992-01-01

    Coatings prepared in a radio-frequency-plasma (plasma assisted chemical vapor deposition) reactor employing in situ laser diagnostics have been tested and characterized. Detailed characterization studies are important to relate gas phase laser diagnostic studies and concurrent heterogeneous modeling efforts to coating characteristics. Establishing how deposition conditions are correlated with coating properties is expected to provide needed methodology for scale up of applications in the hard face protective coating area. After a brief discussion of preparation conditions and mechanical test results, we present results of chemical and physical measurements on these coatings. Measurement techniques include x-ray diffraction, Dektak surface roughness, scanning tunneling microscopy, scanning electron microscopy, and SEI, Auger electron spectroscopy, x-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. The coatings (∼20 μm thick) are very hard (40 GPa at depths over 100 nm), adherent (60 N on scratch test), and sand erosion resistant (>40x as durable as Ti-6Al-4V). They are highly oriented with the c axis (hexagonal-close-packed) normal to the coating surface, rough (∼1 μm), and off-stoichiometry (TiB 2.2 )

  6. Optical and electrical characteristics of plasma enhanced chemical vapor deposition boron carbonitride thin films derived from N-trimethylborazine precursor

    Energy Technology Data Exchange (ETDEWEB)

    Sulyaeva, Veronica S., E-mail: veronica@niic.nsc.ru [Department of Functional Materials Chemistry, Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Kosinova, Marina L.; Rumyantsev, Yurii M.; Kuznetsov, Fedor A. [Department of Functional Materials Chemistry, Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090 (Russian Federation); Kesler, Valerii G. [Laboratory of Physical Principles for Integrated Microelectronics, Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk 630090 (Russian Federation); Kirienko, Viktor V. [Laboratory of Nonequilibrium Semiconductors Systems, Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk 630090 (Russian Federation)

    2014-05-02

    Thin BC{sub x}N{sub y} films have been obtained by plasma enhanced chemical vapor deposition using N-trimethylborazine as a precursor. The films were deposited on Si(100) and fused silica substrates. The grown films were characterized by ellipsometry, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, spectrophotometry, capacitance–voltage and current–voltage measurements. The deposition parameters, such as substrate temperature (373–973 K) and gas phase composition were varied. Low temperature BC{sub x}N{sub y} films were found to be high optical transparent layers in the range of 300–2000 nm, the transmittance as high as 93% has been achieved. BC{sub x}N{sub y} layers are dielectrics with dielectric constant k = 2.2–8.9 depending on the synthesis conditions. - Highlights: • Thin BC{sub x}N{sub y} films have been obtained by plasma enhanced chemical vapor deposition. • N-trimethylborazine was used as a precursor. • Low temperature BC{sub x}N{sub y} films were found to be high optical transparent layers (93%). • BC{sub x}N{sub y} layers are dielectrics with dielectric constant k = 2.2–8.9.

  7. Optical and electrical characteristics of plasma enhanced chemical vapor deposition boron carbonitride thin films derived from N-trimethylborazine precursor

    International Nuclear Information System (INIS)

    Sulyaeva, Veronica S.; Kosinova, Marina L.; Rumyantsev, Yurii M.; Kuznetsov, Fedor A.; Kesler, Valerii G.; Kirienko, Viktor V.

    2014-01-01

    Thin BC x N y films have been obtained by plasma enhanced chemical vapor deposition using N-trimethylborazine as a precursor. The films were deposited on Si(100) and fused silica substrates. The grown films were characterized by ellipsometry, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, spectrophotometry, capacitance–voltage and current–voltage measurements. The deposition parameters, such as substrate temperature (373–973 K) and gas phase composition were varied. Low temperature BC x N y films were found to be high optical transparent layers in the range of 300–2000 nm, the transmittance as high as 93% has been achieved. BC x N y layers are dielectrics with dielectric constant k = 2.2–8.9 depending on the synthesis conditions. - Highlights: • Thin BC x N y films have been obtained by plasma enhanced chemical vapor deposition. • N-trimethylborazine was used as a precursor. • Low temperature BC x N y films were found to be high optical transparent layers (93%). • BC x N y layers are dielectrics with dielectric constant k = 2.2–8.9

  8. Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas.

    Science.gov (United States)

    Adamovich, Igor V; Li, Ting; Lempert, Walter R

    2015-08-13

    This work describes the kinetic mechanism of coupled molecular energy transfer and chemical reactions in low-temperature air, H2-air and hydrocarbon-air plasmas sustained by nanosecond pulse discharges (single-pulse or repetitive pulse burst). The model incorporates electron impact processes, state-specific N(2) vibrational energy transfer, reactions of excited electronic species of N(2), O(2), N and O, and 'conventional' chemical reactions (Konnov mechanism). Effects of diffusion and conduction heat transfer, energy coupled to the cathode layer and gasdynamic compression/expansion are incorporated as quasi-zero-dimensional corrections. The model is exercised using a combination of freeware (Bolsig+) and commercial software (ChemKin-Pro). The model predictions are validated using time-resolved measurements of temperature and N(2) vibrational level populations in nanosecond pulse discharges in air in plane-to-plane and sphere-to-sphere geometry; temperature and OH number density after nanosecond pulse burst discharges in lean H(2)-air, CH(4)-air and C(2)H(4)-air mixtures; and temperature after the nanosecond pulse discharge burst during plasma-assisted ignition of lean H2-mixtures, showing good agreement with the data. The model predictions for OH number density in lean C(3)H(8)-air mixtures differ from the experimental results, over-predicting its absolute value and failing to predict transient OH rise and decay after the discharge burst. The agreement with the data for C(3)H(8)-air is improved considerably if a different conventional hydrocarbon chemistry reaction set (LLNL methane-n-butane flame mechanism) is used. The results of mechanism validation demonstrate its applicability for analysis of plasma chemical oxidation and ignition of low-temperature H(2)-air, CH(4)-air and C(2)H(4)-air mixtures using nanosecond pulse discharges. Kinetic modelling of low-temperature plasma excited propane-air mixtures demonstrates the need for development of a more accurate

  9. Spectroscopic ellipsometry on Si/SiO2/graphene tri-layer system exposed to downstream hydrogen plasma: Effects of hydrogenation and chemical sputtering

    International Nuclear Information System (INIS)

    Eren, Baran; Fu, Wangyang; Marot, Laurent; Calame, Michel; Steiner, Roland; Meyer, Ernst

    2015-01-01

    In this work, the optical response of graphene to hydrogen plasma treatment is investigated with spectroscopic ellipsometry measurements. Although the electronic transport properties and Raman spectrum of graphene change after plasma hydrogenation, ellipsometric parameters of the Si/SiO2/graphene tri-layer system do not change. This is attributed to plasma hydrogenated graphene still being electrically conductive, since the light absorption of conducting 2D materials does not depend on the electronic band structure. A change in the light transmission can only be observed when higher energy hydrogen ions (30 eV) are employed, which chemically sputter the graphene layer. An optical contrast is still apparent after sputtering due to the remaining traces of graphene and hydrocarbons on the surface. In brief, plasma treatment does not change the light transmission of graphene; and when it does, this is actually due to plasma damage rather than plasma hydrogenation

  10. Spectroscopic ellipsometry on Si/SiO{sub 2}/graphene tri-layer system exposed to downstream hydrogen plasma: Effects of hydrogenation and chemical sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Eren, Baran [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fu, Wangyang; Marot, Laurent, E-mail: laurent.marot@unibas.ch; Calame, Michel; Steiner, Roland; Meyer, Ernst [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2015-01-05

    In this work, the optical response of graphene to hydrogen plasma treatment is investigated with spectroscopic ellipsometry measurements. Although the electronic transport properties and Raman spectrum of graphene change after plasma hydrogenation, ellipsometric parameters of the Si/SiO2/graphene tri-layer system do not change. This is attributed to plasma hydrogenated graphene still being electrically conductive, since the light absorption of conducting 2D materials does not depend on the electronic band structure. A change in the light transmission can only be observed when higher energy hydrogen ions (30 eV) are employed, which chemically sputter the graphene layer. An optical contrast is still apparent after sputtering due to the remaining traces of graphene and hydrocarbons on the surface. In brief, plasma treatment does not change the light transmission of graphene; and when it does, this is actually due to plasma damage rather than plasma hydrogenation.

  11. Method of plasma enhanced chemical vapor deposition of diamond using methanol-based solutions

    Science.gov (United States)

    Tzeng, Yonhua (Inventor)

    2009-01-01

    Briefly described, methods of forming diamond are described. A representative method, among others, includes: providing a substrate in a reaction chamber in a non-magnetic-field microwave plasma system; introducing, in the absence of a gas stream, a liquid precursor substantially free of water and containing methanol and at least one carbon and oxygen containing compound having a carbon to oxygen ratio greater than one, into an inlet of the reaction chamber; vaporizing the liquid precursor; and subjecting the vaporized precursor, in the absence of a carrier gas and in the absence in a reactive gas, to a plasma under conditions effective to disassociate the vaporized precursor and promote diamond growth on the substrate in a pressure range from about 70 to 130 Torr.

  12. Modeling the chemical kinetics of atmospheric plasma for cell treatment in a liquid solution

    International Nuclear Information System (INIS)

    Kim, H. Y.; Kang, S. K.; Lee, H. Wk.; Lee, H. W.; Kim, G. C.; Lee, J. K.

    2012-01-01

    Low temperature atmospheric pressure plasmas have been known to be effective for living cell inactivation in a liquid solution but it is not clear yet which species are key factors for the cell treatment. Using a global model, we elucidate the processes through which pH level in the solution is changed from neutral to acidic after plasma exposure and key components with pH and air variation. First, pH level in a liquid solution is changed by He + and He(2 1 S) radicals. Second, O 3 density decreases as pH level in the solution decreases and air concentration decreases. It can be a method of removing O 3 that causes chest pain and damages lung tissue when the density is very high. H 2 O 2 , HO 2 , and NO radicals are found to be key factors for cell inactivation in the solution with pH and air variation.

  13. Plasma-enhanced chemical vapor deposition of graphene on copper substrates

    Directory of Open Access Journals (Sweden)

    Nicolas Woehrl

    2014-04-01

    Full Text Available A plasma enhanced vapor deposition process is used to synthesize graphene from a hydrogen/methane gas mixture on copper samples. The graphene samples were transferred onto SiO2 substrates and characterized by Raman spectroscopic mapping and atomic force microscope topographical mapping. Analysis of the Raman bands shows that the deposited graphene is clearly SLG and that the sheets are deposited on large areas of several mm2. The defect density in the graphene sheets is calculated using Raman measurements and the influence of the process pressure on the defect density is measured. Furthermore the origin of these defects is discussed with respect to the process parameters and hence the plasma environment.

  14. Modular and efficient ozone systems based on massively parallel chemical processing in microchannel plasma arrays: performance and commercialization

    Science.gov (United States)

    Kim, M.-H.; Cho, J. H.; Park, S.-J.; Eden, J. G.

    2017-08-01

    Plasmachemical systems based on the production of a specific molecule (O3) in literally thousands of microchannel plasmas simultaneously have been demonstrated, developed and engineered over the past seven years, and commercialized. At the heart of this new plasma technology is the plasma chip, a flat aluminum strip fabricated by photolithographic and wet chemical processes and comprising 24-48 channels, micromachined into nanoporous aluminum oxide, with embedded electrodes. By integrating 4-6 chips into a module, the mass output of an ozone microplasma system is scaled linearly with the number of modules operating in parallel. A 115 g/hr (2.7 kg/day) ozone system, for example, is realized by the combined output of 18 modules comprising 72 chips and 1,800 microchannels. The implications of this plasma processing architecture for scaling ozone production capability, and reducing capital and service costs when introducing redundancy into the system, are profound. In contrast to conventional ozone generator technology, microplasma systems operate reliably (albeit with reduced output) in ambient air and humidity levels up to 90%, a characteristic attributable to the water adsorption/desorption properties and electrical breakdown strength of nanoporous alumina. Extensive testing has documented chip and system lifetimes (MTBF) beyond 5,000 hours, and efficiencies >130 g/kWh when oxygen is the feedstock gas. Furthermore, the weight and volume of microplasma systems are a factor of 3-10 lower than those for conventional ozone systems of comparable output. Massively-parallel plasmachemical processing offers functionality, performance, and commercial value beyond that afforded by conventional technology, and is currently in operation in more than 30 countries worldwide.

  15. Studies of internal stress in diamond films prepared by DC plasma chemical vapour deposition

    International Nuclear Information System (INIS)

    Wang Wanlu; Gao Jinying; Liao Kejun; Liu Anmin

    1992-01-01

    The internal stress in diamond thin films deposited by DC plasma CVD was studied as a function of methane concentration and deposited temperature. Experimental results have shown that total stress in diamond thin films is sensitive to the deposition conditions. The results also indicate that the compressive stress can be explained in terms of amorphous state carbon and hydrogen, and tensile stress is ascribed to the grain boundary relaxation model due to high internal surface area and microstructure with voids

  16. A comparative study of nitrogen plasma effect on field emission characteristics of single wall carbon nanotubes synthesized by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avshish; Parveen, Shama; Husain, Samina; Ali, Javid [Department of Physics, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Zulfequar, Mohammad [Department of Physics, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Harsh [Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Husain, Mushahid, E-mail: mush_reslab@rediffmail.com [Department of Physics, Jamia Millia Islamia (A Central University), New Delhi 110025 (India); Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia (A Central University), New Delhi 110025 (India)

    2014-12-15

    Highlights: • Vertically aligned single wall carbon nanotubes (SWCNTs) have been successfully grown on nickel (Ni) deposited silicon substrate. • The diameter distribution of the grown (SWCNTs) is in the range 1–2 nm. • A current density of 25.0 mA/cm{sup 2} at 1.9 V/μm of the grown SWCNTs is observed with a high turn-on field (E{sub to}) of 1.3 V/μm. • After N{sub 2} nitrogen plasma treatment, huge current density of 81.5 mA/cm{sup 2} at 2.0 V/μm was recorded with low E{sub to} of 1.2 V/μm. • The comparison of these two typical results indicates a drastic enhancement in the field emission properties after plasma treatments. - Abstract: Vertically aligned single wall carbon nanotubes (SWCNTs) with large scale control of diameter, length and alignment have successfully been grown by plasma enhanced chemical vapor deposition (PECVD) system. The nickel (Ni) as catalyst deposited on silicon (Si) substrate was used to grow the SWCNTs. Field emission (FE) characteristics of the as grown SWCNTs were measured using indigenously designed setup in which a diode is configured in such a way that by applying negative voltage on the copper plate (cathode) with respect to stainless steel anode plate, current density can be recorded. To measure the FE characteristics, SWCNTs film pasted on the copper plate with silver epoxy was used as electron emitter source. The effective area of anode was ∼78.5 mm{sup 2} for field emission measurements. The emission measurements were carried out under high vacuum pressure of the order of 10{sup −6} Torr to minimize the electron scattering and degradation of the emitters. The distance between anode and cathode was kept 500 μm (constant) during entire field emission studies. The grown SWCNTs are excellent field emitters, having emission current density higher than 25 mA/cm{sup 2} at turn-on field 1.3 V/μm. In order to enhance the field emission characteristics, the as grown SWCNTs have been treated under nitrogen (N{sub 2

  17. Plasma-Sprayed Hydroxylapatite-Based Coatings: Chemical, Mechanical, Microstructural, and Biomedical Properties

    Science.gov (United States)

    Heimann, Robert B.

    2016-06-01

    This contribution discusses salient properties and functions of hydroxylapatite (HA)-based plasma-sprayed coatings, including the effect on biomedical efficacy of coating thickness, phase composition and distribution, amorphicity and crystallinity, porosity and surface roughness, cohesion and adhesion, micro- and nano-structured surface morphology, and residual coating stresses. In addition, it will provide details of the thermal alteration that HA particles undergo in the extremely hot plasma jet that leads to dehydroxylated phases such as oxyhydroxylapatite (OHA) and oxyapatite (OA) as well as thermal decomposition products such as tri-(TCP) and tetracalcium phosphates (TTCP), and quenched phases such as amorphous calcium phosphate (ACP). The contribution will further explain the role of ACP during the in vitro interaction of the as-deposited coatings with simulated body fluid resembling the composition of extracellular fluid (ECF) as well as the in vivo responses of coatings to the ECF and the host tissue, respectively. Finally, it will briefly describe performance profiles required to fulfill biological functions of osteoconductive bioceramic coatings designed to improve osseointegration of hip endoprostheses and dental root implants. In large parts, the content of this contribution is a targeted review of work done by the author and his students and coworkers over the last two decades. In addition, it is considered a stepping stone toward a standard operation procedure aimed at depositing plasma-sprayed bioceramic implant coatings with optimum properties.

  18. Optical, mechanical and surface properties of amorphous carbonaceous thin films obtained by plasma enhanced chemical vapor deposition and plasma immersion ion implantation and deposition

    Science.gov (United States)

    Turri, Rafael G.; Santos, Ricardo M.; Rangel, Elidiane C.; da Cruz, Nilson C.; Bortoleto, José R. R.; Dias da Silva, José H.; Antonio, César Augusto; Durrant, Steven F.

    2013-09-01

    Diverse amorphous hydrogenated carbon-based films (a-C:H, a-C:H:F, a-C:H:N, a-C:H:Cl and a-C:H:Si:O) were obtained by radiofrequency plasma enhanced chemical vapor deposition (PECVD) and plasma immersion ion implantation and deposition (PIIID). The same precursors were used in the production of each pair of each type of film, such as a-C:H, using both PECVD and PIIID. Optical properties, namely the refractive index, n, absorption coefficient, α, and optical gap, ETauc, of these films were obtained via transmission spectra in the ultraviolet-visible near-infrared range (wavelengths from 300 to 3300 nm). Film hardness, elastic modulus and stiffness were obtained as a function of depth using nano-indentation. Surface energy values were calculated from liquid drop contact angle data. Film roughness and morphology were assessed using atomic force microscopy (AFM). The PIIID films were usually thinner and possessed higher refractive indices than the PECVD films. Determined refractive indices are consistent with literature values for similar types of films. Values of ETauc were increased in the PIIID films compared to the PECVD films. An exception was the a-C:H:Si:O films, for which that obtained by PIIID was thicker and exhibited a decreased ETauc. The mechanical properties - hardness, elastic modulus and stiffness - of films produced by PECVD and PIIID generally present small differences. An interesting effect is the increase in the hardness of a-C:H:Cl films from 1.0 to 3.0 GPa when ion implantation is employed. Surface energy correlates well with surface roughness. The implanted films are usually smoother than those obtained by PECVD.

  19. Optical, mechanical and surface properties of amorphous carbonaceous thin films obtained by plasma enhanced chemical vapor deposition and plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Turri, Rafael G.; Santos, Ricardo M.; Rangel, Elidiane C.; Cruz, Nilson C. da; Bortoleto, José R.R.; Dias da Silva, José H.; Antonio, César Augusto; Durrant, Steven F.

    2013-01-01

    Diverse amorphous hydrogenated carbon-based films (a-C:H, a-C:H:F, a-C:H:N, a-C:H:Cl and a-C:H:Si:O) were obtained by radiofrequency plasma enhanced chemical vapor deposition (PECVD) and plasma immersion ion implantation and deposition (PIIID). The same precursors were used in the production of each pair of each type of film, such as a-C:H, using both PECVD and PIIID. Optical properties, namely the refractive index, n, absorption coefficient, α, and optical gap, E Tauc , of these films were obtained via transmission spectra in the ultraviolet–visible near-infrared range (wavelengths from 300 to 3300 nm). Film hardness, elastic modulus and stiffness were obtained as a function of depth using nano-indentation. Surface energy values were calculated from liquid drop contact angle data. Film roughness and morphology were assessed using atomic force microscopy (AFM). The PIIID films were usually thinner and possessed higher refractive indices than the PECVD films. Determined refractive indices are consistent with literature values for similar types of films. Values of E Tauc were increased in the PIIID films compared to the PECVD films. An exception was the a-C:H:Si:O films, for which that obtained by PIIID was thicker and exhibited a decreased E Tauc . The mechanical properties – hardness, elastic modulus and stiffness – of films produced by PECVD and PIIID generally present small differences. An interesting effect is the increase in the hardness of a-C:H:Cl films from 1.0 to 3.0 GPa when ion implantation is employed. Surface energy correlates well with surface roughness. The implanted films are usually smoother than those obtained by PECVD.

  20. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  1. In vitro characterization of two different atmospheric plasma jet chemical functionalizations of titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mussano, F., E-mail: federico.mussano@unito.it [CIR Dental School, Department of Surgical Sciences UNITO, via Nizza 230, 10126, Turin (Italy); Genova, T. [CIR Dental School, Department of Surgical Sciences UNITO, via Nizza 230, 10126, Turin (Italy); Department of Life Sciences and Systems Biology, UNITO, via Accademia Albertina 13, 10123, Turin (Italy); Verga Falzacappa, E. [Department of Molecular Science and Nanosystems, UNIVE, Via Torino 155, 30170, Venezia (Italy); Nadir srl, Via Torino 155, 30170 Venezia (Italy); Scopece, P. [Nadir srl, Via Torino 155, 30170 Venezia (Italy); Munaron, L. [Department of Life Sciences and Systems Biology, UNITO, via Accademia Albertina 13, 10123, Turin (Italy); Centre for Nanostructured Interfaces and Surfaces (NIS) (Italy); Rivolo, P.; Mandracci, P. [Politecnico di Torino, Department of Applied Science and Technology, Materials and Microsoystems Laboratory (ChiLab), Corso Duca degli Abruzzi 24, 10129, Torino (Italy); Benedetti, A. [Department of Molecular Science and Nanosystems, UNIVE, Via Torino 155, 30170, Venezia (Italy); Carossa, S. [CIR Dental School, Department of Surgical Sciences UNITO, via Nizza 230, 10126, Turin (Italy); Patelli, A. [Department of Physics and Astronomy, UNIPD, via Marzolo 8, 35122 Padova (Italy)

    2017-07-01

    Highlights: • NH{sub 2}-Ti and COOH/R-Ti obtained via atmospheric plasma jet RF-APPJ portable equipment. • Higher quantity of adsorbed proteins and improved cell adhesion on treated surfaces. • More tapered and elongated cells on NH{sub 2}-Ti compared to COOH/R-Ti. • Higher osteocalcin expression on NH{sub 2}-Ti. - Abstract: Plasma surface activation and plasma polymers deposition are promising technologies capable to modulate biologically relevant surface features of biomaterials. The purpose of this study was to evaluate the biological effects of two different surface modifications, i.e. amine (NH{sub 2}-Ti) and carboxylic/esteric (COOH/R-Ti) functionalities obtained from 3-aminopropyltriethoxysilane (3-APTES) and methylmethacrylate (MMA) precursors, respectively, through an atmospheric plasma jet RF-APPJ portable equipment. The coatings were characterized by Scanning Electron Microscopy, FT-IR spectroscopy, XPS and surface energy calculations. Stability in water and after UV sterilization were also verified. The pre-osteoblastic murine cell line MC3T3-E1 was used to perform the in-vitro tests. The treated samples showed a higher quantity of adsorbed proteins and improved osteoblast cells adhesion on the surfaces compared to the pristine titanium, in particular the COOH/R-Ti led to a nearly two-fold improvement. Cell proliferation on coated samples was initially (at 24 h) lower than on titanium control, while, at 48 h, COOH/R-Ti reached the proliferation rate of pristine titanium. Cells grown on NH{sub 2}-Ti were more tapered and elongated in shape with lower areas than on COOH/R-Ti enriched surfaces. Finally, NH{sub 2}-Ti significantly enhanced osteocalcin production, starting from 14 days, while COOH/R-Ti had this effect only from 21 days. Notably, NH{sub 2}-Ti was more efficient than COOH/R-Ti at 21 days. The amine functionality elicited the most relevant osteogenic effect in terms of osteocalcin expression, thus establishing an interesting correlation

  2. The physical and chemical properties of plasma treated ultra-high-molecular-weight polyethylene fibers

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Teodoru, Steluta; Hansen, Charles M.

    2011-01-01

    A uniform and smooth transfer of stresses across the polymer matrix/fiber interface is enhanced when adhesion between the matrix and fiber surface is optimized. In the absence of covalent bonds matching the Hansen solubility (cohesion) parameters (HSP) of the fiber surface with the HSP of a matrix...... at 18.0, 1.2, and 1.4, all in MPa½. The dispersion parameter has been lowered somewhat by the plasma treatment, while the polar and hydrogen bonding parameters are much higher. The HSP methodology predicts enhanced adhesion is possible by skillful use of anhydride and nitrile functional groups in matrix...

  3. Ultralow k films by using a plasma-enhanced chemical vapor deposition porogen approach: Study of the precursor reaction mechanisms

    International Nuclear Information System (INIS)

    Castex, A.; Jousseaume, V.; Deval, J.; Bruat, J.; Favennec, L.; Passemard, G.

    2008-01-01

    As interconnects are scaled down, much effort is made to achieve ultralow k material with a dielectric constant lower than 2.5. Thus, many new precursors are investigated in plasma-enhanced chemical vapor deposition. This is particularly true with the porogen approach where two molecules are used: an organosilicon to create the silicon matrix and an organic molecule ''porogen'' that creates material porosity during a post-treatment such as annealing. In this article, the influence of the organosilicon molecular structure is investigated. Two ''matrix precursors'' with different structures are therefore compared. The first one, referred to as D5, has a ring structure (decamethyl pentacyclosiloxane); the second one, referred to as DEOMS, has a star structure (diethoxymethyl silane). The porogen organic molecule, referred to as CHO, is cyclohexen oxide. The fragmentation paths of the precursor molecules in the plasma are investigated by quadrupole mass spectroscopy and the film structure is studied by Fourier transform infrared spectroscopy. The mass spectroscopy analysis shows that the fragmentation in plasma is highest for DEOMS, intermediate for CHO, and lowest for D5 in comparable process conditions. At the maximum plasma power setting, the loss rate, which yields molecule consumption, is 43%-81% for the D5-CHO mixture, respectively, and 73%-37% for the DEOMS-CHO mixture, respectively. This is related to higher bond-dissociation energy for the siloxane (Si-O-Si) link in D5 than silane (Si-H), silylethoxyde (Si-OC 2 H 5 ) in DEOMS, or C-C and epoxy cycle in CHO. Indeed, a higher electron-energy relative threshold for dissociation under electron impact is measured for D5 (around 7 eV) than for DEOMS and CHO (around 4 eV). Moreover, the fragment structures differ from one precursor to another. Methyl groups are abstracted from D5 and a few polysiloxane chains are produced from pentacycle opening and fragmentation. In the case of DEOMS, many single silicon

  4. Time-dependent two-temperature chemically non-equilibrium modelling of high-power Ar-N2 pulse-modulated inductively coupled plasmas at atmospheric pressure

    International Nuclear Information System (INIS)

    Tanaka, Yasunori

    2006-01-01

    A time-dependent, two-dimensional, two-temperature and chemical non-equilibrium model was developed for high-power Ar-N 2 pulse-modulated inductively coupled plasmas (PMICPs) at atmospheric pressure. The high-power PMICP is a new technique for sustaining high-power induction plasmas. It can control the plasma temperature and radical densities in the time domain. The PMICP promotes non-equilibrium effects by a sudden application of electric field, even in the high-power density plasmas. The developed model accounts separately for the time-dependent energy conservation equations of electrons and heavy particles. This model also considers reaction heat effects and energy transfer between electrons and heavy particles as well as enthalpy flow resulting from diffusion caused by the particle density gradient. Chemical non-equilibrium effects are also taken into account by solving time-dependent mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from 30 chemical reactions. Transport and thermodynamic properties of Ar-N 2 plasmas are calculated self-consistently using the first order approximation of the Chapman-Enskog method at each position and iteration using the local particle composition, heavy particle temperature and electron temperature. This model is useful to discuss time evolution in temperature, gas flow fields and distribution of chemical species

  5. Analysis of human plasma metabolites across different liquid chromatography/mass spectrometry platforms: Cross-platform transferable chemical signatures.

    Science.gov (United States)

    Telu, Kelly H; Yan, Xinjian; Wallace, William E; Stein, Stephen E; Simón-Manso, Yamil

    2016-03-15

    The metabolite profiling of a NIST plasma Standard Reference Material (SRM 1950) on different liquid chromatography/mass spectrometry (LC/MS) platforms showed significant differences. Although these findings suggest caution when interpreting metabolomics results, the degree of overlap of both profiles allowed us to use tandem mass spectral libraries of recurrent spectra to evaluate to what extent these results are transferable across platforms and to develop cross-platform chemical signatures. Non-targeted global metabolite profiles of SRM 1950 were obtained on different LC/MS platforms using reversed-phase chromatography and different chromatographic scales (conventional HPLC, UHPLC and nanoLC). The data processing and the metabolite differential analysis were carried out using publically available (XCMS), proprietary (Mass Profiler Professional) and in-house software (NIST pipeline). Repeatability and intermediate precision showed that the non-targeted SRM 1950 profiling was highly reproducible when working on the same platform (relative standard deviation (RSD) HPLC, UHPLC and nanoLC) on the same platform. A substantial degree of overlap (common molecular features) was also found. A procedure to generate consistent chemical signatures using tandem mass spectral libraries of recurrent spectra is proposed. Different platforms rendered significantly different metabolite profiles, but the results were highly reproducible when working within one platform. Tandem mass spectral libraries of recurrent spectra are proposed to evaluate the degree of transferability of chemical signatures generated on different platforms. Chemical signatures based on our procedure are most likely cross-platform transferable. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

  6. Tetrapyrrole-photosensitizers vectorization and plasma LDL: a physico-chemical approach.

    Science.gov (United States)

    Bonneau, Stéphanie; Vever-Bizet, Christine; Mojzisova, Halina; Brault, Daniel

    2007-11-01

    A photosensitizer is defined as a chemical entity able to induce, under light-irradiation effect, a chemical or physical alteration of another chemical entity. Thanks to their preferential retention in proliferating tissues, some photosensitizers are therapeutically used such as in photodynamic therapy (PDT). Besides, this method has already been approved for several indications. The selectivity of photosenzitizers for cells in proliferation involves both their association with low density lipoproteins (LDLs) and their ability to cross membranes under various pH conditions. The photosensitizers used are in most cases based on the porphyrin structure, but other compounds, of which far-red-light absorption properties are most compatible with biological tissues irradiation, have been developed, such as phthalocyanines. This paper presents physico-chemical studies of the interaction of a disulfonated aluminium phthalocyanine (AlPcS2) with human LDLs. The data obtained are compared with the parameters of the interaction of these lipoproteins with deuteroporphyrin (DP) and chlorin e6 (Ce6). A close attention is paid to the dynamic aspects of these phenomena. The data obtained on these simple systems then allowed us to interpret the sub-cellular localization of the photosensitizers on a human line of fibroblasts, and to evaluate the influence of LDLs on the intracellular distribution of the compounds. This last point is of major importance because the localization of such photosensitizers (in particular AlPcS2) in endocytic vesicles and their subsequent ability to induce a release of the contents of these vesicles - including externally added macromolecules - into the cytosol is the basis for a recent method for macromolecule activation, named photochemical internalization (PCI). PCI has been shown to potentiate the biological activity of a large variety of macromolecules. The comprehension of the mechanisms governing this particular sub-cellular localization could allow

  7. Atomic force microscopy indentation of fluorocarbon thin films fabricated by plasma enhanced chemical deposition at low radio frequency power

    International Nuclear Information System (INIS)

    Sirghi, L.; Ruiz, A.; Colpo, P.; Rossi, F.

    2009-01-01

    Atomic force microscopy (AFM) indentation technique is used for characterization of mechanical properties of fluorocarbon (CF x ) thin films obtained from C 4 F 8 gas by plasma enhanced chemical vapour deposition at low r.f. power (5-30 W) and d.c. bias potential (10-80 V). This particular deposition method renders films with good hydrophobic property and high plastic compliance. Commercially available AFM probes with stiff cantilevers (10-20 N/m) and silicon sharpened tips (tip radius < 10 nm) are used for indentations and imaging of the resulted indentation imprints. Force depth curves and imprint characteristics are used for determination of film hardness, elasticity modulus and plasticity index. The measurements show that the decrease of the discharge power results in deposition of films with decreased hardness and stiffness and increased plasticity index. Nanolithography based on AFM indentation is demonstrated on thin films (thickness of 40 nm) with good plastic compliance.

  8. Synthesis and growth mechanism of Fe-catalyzed carbon nanotubes by plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Jiang Jun; Feng Tao; Cheng Xinhong; Dai Lijuan; Cao Gongbai; Jiang Bingyao; Wang Xi; Liu Xianghuai; Zou Shichang

    2006-01-01

    Plasma-enhanced chemical vapor deposition (PECVD) was used to grow Fe-catalyzed carbon nanotubes (CNTs). The nanotubes had a uniform diameter in the range of about 10-20 nm. A base growth mode was responsible for the CNTs growth using a mixture of H 2 (60 sccm) and C 2 H 2 (15 sccm). For a mixture of H 2 (100 sccm) and C 2 H 2 (25 sccm), a complicated growth mechanism took place involving both the base growth and the tip growth. X-ray photoelectron spectroscopy measurements revealed that the grown CNTs contained C-H covalent bonds and Fe-C bonds located at the interface between them and the substrates. The factors determining the growth mechanism of CNTs are discussed and their growth mechanisms with the different gas ratios are suggested

  9. Properties of Erbium Doped Hydrogenated Amorphous Carbon Layers Fabricated by Sputtering and Plasma Assisted Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2008-01-01

    Full Text Available We report about properties of carbon layers doped with Er3+ ions fabricated by Plasma Assisted Chemical Vapor Deposition (PACVD and by sputtering on silicon or glass substrates. The structure of the samples was characterized by X-ray diffraction and their composition was determined by Rutherford Backscattering Spectroscopy and Elastic Recoil Detection Analysis. The Absorbance spectrum was taken in the spectral range from 400 nm to 600 nm. Photoluminescence spectra were obtained using two types of Ar laser (λex=514.5 nm, lex=488 nm and also using a semiconductor laser (λex=980 nm. Samples fabricated by magnetron sputtering exhibited typical emission at 1530 nm when pumped at 514.5 nm. 

  10. Non-catalytic direct synthesis of graphene on Si (111) wafers by using inductively-coupled plasma chemical vapor deposition

    Science.gov (United States)

    Hwang, Sung Won; Shin, Hyunho; Lee, Bongsoo; Choi, Suk-Ho

    2016-08-01

    We employ inductively-coupled plasma chemical vapor deposition for non-catalytic growth of graphene on a Si (111) wafer or glass substrate, which is useful for practical device applications of graphene without transfer processes. At a RF power (P) of 500 W under C2H2 flow, defect-free 3 ˜ 5-layer graphene is grown on Si (111) wafers, but on glass substrate, the layer is thicker and defective, as characterized by Raman spectroscopy and electron microscopy. The graphene is produced on Si (111) for P down to 190 W whereas it is almost not formed on glass for P < 250 W, possibly resulting from the weak catalytic-reaction-like effect on glass. These results are discussed based on possible growth mechanisms.

  11. Structural and optical characterization of self-assembled Ge nanocrystal layers grown by plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Saeed, Saba; Buters, Frank; Dohnalova, Katerina; Wosinski, Lech; Gregorkiewicz, Tom

    2014-10-10

    We present a structural and optical study of solid-state dispersions of Ge nanocrystals prepared by plasma-enhanced chemical vapor deposition. Structural analysis shows the presence of nanocrystalline germanium inclusions embedded in an amorphous matrix of Si-rich SiO(2).Optical characterization reveals two prominent emission bands centered around 2.6 eV and 3.4 eV, and tunable by excitation energy. In addition, the lower energy band shows an excitation power-dependent blue shift of up to 0.3 eV. Decay dynamics of the observed emission contains fast (nanosecond) and slow (microseconds) components, indicating contributions of several relaxation channels. Based on these material characteristics, a possible microscopic origin of the individual emission bands is discussed.

  12. An economic analysis of the deposition of electrochromic WO3 via sputtering or plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Garg, D.; Henderson, P.B.; Hollingsworth, R.E.; Jensen, D.G.

    2005-01-01

    The costs of manufacturing electrochromic WO 3 thin films deposited by either radio frequency plasma enhanced chemical vapor deposition (PECVD) or DC reactive magnetron sputtering of metal targets were modeled. Both inline systems for large area glass substrates and roll-to-roll systems for flexible webs were compared. Costs of capital, depreciation, raw materials, labor, power, and other miscellaneous items were accounted for in the model. The results predict that on similar sized systems, PECVD can produce electrochromic WO 3 for as little as one-third the cost, and have more than 10 times the annual production capacity of sputtering. While PECVD cost is dominated by raw materials, primarily WF 6 , sputtering cost is dominated by labor and depreciation

  13. Research on the discharge characteristics for water tree in crosslinked polyethylene cable based on plasma-chemical model

    Science.gov (United States)

    Fan, Yang; Qi, Yang; Bing, Gao; Rong, Xia; Yanjie, Le; Iroegbu, Paul Ikechukwu

    2018-03-01

    Water tree is the predominant defect in high-voltage crosslinked polyethylene cables. The microscopic mechanism in the discharge process is not fully understood; hence, a drawback is created towards an effective method to evaluate the insulation status. In order to investigate the growth of water tree, a plasma-chemical model is developed. The dynamic characteristics of the discharge process including voltage waveform, current waveform, electron density, electric potential, and electric field intensity are analyzed. Our results show that the distorted electric field is the predominant contributing factor of electron avalanche formation, which inevitably leads to the formation of pulse current. In addition, it is found that characteristic parameters such as the pulse width and pulse number have a great relevance to the length of water tree. Accordingly, the growth of water tree can be divided into the initial stage, development stage, and pre-breakdown stage, which provides a reference for evaluating the deteriorated stages of crosslinked polyethylene cables.

  14. In situ growth rate measurements during plasma-enhanced chemical vapour deposition of vertically aligned multiwall carbon nanotube films

    International Nuclear Information System (INIS)

    Joensson, M; Nerushev, O A; Campbell, E E B

    2007-01-01

    In situ laser reflectivity measurements are used to monitor the growth of multiwalled carbon nanotube (MWCNT) films grown by DC plasma-enhanced chemical vapour deposition (PECVD) from an iron catalyst film deposited on a silicon wafer. In contrast to thermal CVD growth, there is no initial increase in the growth rate; instead, the initial growth rate is high (as much as 10 μm min -1 ) and then drops off rapidly to reach a steady level (2 μm min -1 ) for times beyond 1 min. We show that a limiting factor for growing thick films of multiwalled nanotubes (MWNTs) using PECVD can be the formation of an amorphous carbon layer at the top of the growing nanotubes. In situ reflectivity measurements provide a convenient technique for detecting the onset of the growth of this layer

  15. Modeling of plasma chemical processes in the artificial ionized layer in the upper atmosphere by the nanosecond corona discharge

    Science.gov (United States)

    Vikharev, A. L.; Gorbachev, A. M.; Ivanov, O. A.; Kolisko, A. L.; Litvak, A. G.

    1993-08-01

    The plasma chemical processes in the corona discharge formed in air by a series of high voltage pulses of nanosecond duration are investigated experimentally. The experimental conditions (reduced electric field, duration and repetition frequency of the pulses, gas pressure in the chamber) modeled the regime of creation of the artificial ionized layer (AIL) in the upper atmosphere by a nanosecond microwave discharge. It was found that in a nanosecond microwave discharge predominantly generation of ozone occurs, and that the production of nitrogen dioxide is not large. The energy expenditures for the generation of one O 3 molecule were about 15 eV. On the basis of the experimental results the prognosis of the efficiency of ozone generation in AIL was made.

  16. Si Nano wires Produced by Very High Frequency Plasma Enhanced Chemical Vapor Deposition (PECVD) via VLS Mechanism

    International Nuclear Information System (INIS)

    Yussof Wahab; Yussof Wahab; Habib Hamidinezhad; Habib Hamidinezhad

    2013-01-01

    Silicon nano wires (SiNWs) with diameter of about a few nanometers and length of 3 μm on silicon wafers were synthesized by very high frequency plasma enhanced chemical vapor deposition. Scanning electron microscopy (SEM) observations showed that the silicon nano wires were grown randomly and energy-dispersive X-ray spectroscopy analysis indicates that the nano wires have the composition of Si, Au and O elements. The SiNWs were characterized by high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. SEM micrographs displayed SiNWs that are needle-like with a diameter ranged from 30 nm at the top to 100 nm at the bottom of the wire and have length a few of micrometers. In addition, HRTEM showed that SiNWs consist of crystalline silicon core and amorphous silica layer. (author)

  17. An economic analysis of the deposition of electrochromic WO{sub 3} via sputtering or plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Garg, D. [Air Products and Chemicals Inc., 7201 Hamilton Blvd., Allentown, PA 18195-7201 (United States); Henderson, P.B. [Air Products and Chemicals Inc., 7201 Hamilton Blvd., Allentown, PA 18195-7201 (United States)]. E-mail: henderpb@airproducts.co; Hollingsworth, R.E. [ITN Energy Systems Inc., 8130 Shaffer Pkwy, Littleton, CO 80127 (United States); Jensen, D.G. [ITN Energy Systems Inc., 8130 Shaffer Pkwy, Littleton, CO 80127 (United States)

    2005-06-15

    The costs of manufacturing electrochromic WO{sub 3} thin films deposited by either radio frequency plasma enhanced chemical vapor deposition (PECVD) or DC reactive magnetron sputtering of metal targets were modeled. Both inline systems for large area glass substrates and roll-to-roll systems for flexible webs were compared. Costs of capital, depreciation, raw materials, labor, power, and other miscellaneous items were accounted for in the model. The results predict that on similar sized systems, PECVD can produce electrochromic WO{sub 3} for as little as one-third the cost, and have more than 10 times the annual production capacity of sputtering. While PECVD cost is dominated by raw materials, primarily WF{sub 6}, sputtering cost is dominated by labor and depreciation.

  18. Characterization of thin TiO2 films prepared by plasma enhanced chemical vapour deposition for optical and photocatalytic applications

    International Nuclear Information System (INIS)

    Sobczyk-Guzenda, A.; Gazicki-Lipman, M.; Szymanowski, H.; Kowalski, J.; Wojciechowski, P.; Halamus, T.; Tracz, A.

    2009-01-01

    Thin titanium oxide films were deposited using a radio frequency (RF) plasma enhanced chemical vapour deposition method. Their optical properties and thickness were determined by means of ultraviolet-visible absorption spectrophotometry. Films of the optical parameters very close to those of titanium dioxide have been obtained at the high RF power input. Their optical quality is high enough to allow for their use in a construction of stack interference optical filters. At the same time, these materials exhibit strong photocatalytic effects. The results of structural analysis, carried out by Raman Shift Spectroscopy, show that the coatings posses amorphous structure. However, Raman spectra of the same films subjected to thermal annealing at 450 o C disclose an appearance of a crystalline form, namely that of anatase. Surface morphology of the films has also been characterized by Atomic Force Microscopy revealing granular, broccoli-like topography of the films.

  19. Formation of apatite on hydrogenated amorphous silicon (a-Si:H) film deposited by plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Liu Xuanyong; Chu, Paul K.; Ding Chuanxian

    2007-01-01

    Hydrogenated amorphous silicon films were fabricated on p-type, 100 mm diameter silicon wafers by plasma-enhanced chemical vapor deposition (PECVD) using silane and hydrogen. The structure and composition of the hydrogenated amorphous silicon films were investigated using micro-Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM). The hydrogenated amorphous silicon films were subsequently soaked in simulated body fluids to evaluate apatite formation. Carbonate-containing hydroxyapatite (bone-like apatite) was formed on the surface suggesting good bone conductivity. The amorphous structure and presence of surface Si-H bonds are believed to induce apatite formation on the surface of the hydrogenated amorphous silicon film. A good understanding of the surface bioactivity of silicon-based materials and means to produce a bioactive surface is important to the development of silicon-based biosensors and micro-devices that are implanted inside humans

  20. Formation of apatite on hydrogenated amorphous silicon (a-Si:H) film deposited by plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xuanyong [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China) and Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: xyliu@mail.sic.ac.cn; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)]. E-mail: paul.chu@cityu.edu.hk; Ding Chuanxian [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2007-01-15

    Hydrogenated amorphous silicon films were fabricated on p-type, 100 mm diameter <1 0 0> silicon wafers by plasma-enhanced chemical vapor deposition (PECVD) using silane and hydrogen. The structure and composition of the hydrogenated amorphous silicon films were investigated using micro-Raman spectroscopy and cross-sectional transmission electron microscopy (XTEM). The hydrogenated amorphous silicon films were subsequently soaked in simulated body fluids to evaluate apatite formation. Carbonate-containing hydroxyapatite (bone-like apatite) was formed on the surface suggesting good bone conductivity. The amorphous structure and presence of surface Si-H bonds are believed to induce apatite formation on the surface of the hydrogenated amorphous silicon film. A good understanding of the surface bioactivity of silicon-based materials and means to produce a bioactive surface is important to the development of silicon-based biosensors and micro-devices that are implanted inside humans.

  1. Transport properties of field effect transistors with randomly networked single walled carbon nanotubes grown by plasma enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Kim, Un Jeong; Park, Wanjun

    2009-01-01

    The transport properties of randomly networked single walled carbon nanotube (SWNT) transistors with different channel lengths of L c = 2-10 μm were investigated. Randomly networked SWNTs were directly grown for the two different densities of ρ ∼ 25 μm -2 and ρ ∼ 50 μm -2 by water plasma enhanced chemical vapour deposition. The field effect transport is governed mainly by formation of the current paths that is related to the nanotube density. On the other hand, the off-state conductivity deviates from linear dependence for both nanotube density and channel length. The field effect mobility of holes is estimated as 4-13 cm 2 V -1 s -1 for the nanotube transistors based on the simple MOS theory. The mobility is increased for the higher density without meaningful dependence on the channel lengths.

  2. Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Jamin M.; Catledge, Shane A., E-mail: catledge@uab.edu

    2016-02-28

    Graphical abstract: - Highlights: • A detailed phase analysis after PECVD boriding shows WCoB, CoB and/or W{sub 2}CoB{sub 2}. • EDS of PECVD borides shows boron diffusion into the carbide grain structure. • Nanoindentation hardness and modulus of borides is 23–27 GPa and 600–780 GPa. • Scratch testing shows hard coating with cracking at 40N and spallation at 70N. - Abstract: Strengthening of cemented tungsten carbide by boriding is used to improve the wear resistance and lifetime of carbide tools; however, many conventional boriding techniques render the bulk carbide too brittle for extreme conditions, such as hard rock drilling. This research explored the variation in metal-boride phase formation during the microwave plasma enhanced chemical vapor deposition process at surface temperatures from 700 to 1100 °C. We showed several well-adhered metal-boride surface layers consisting of WCoB, CoB and/or W{sub 2}CoB{sub 2} with average hardness from 23 to 27 GPa and average elastic modulus of 600–730 GPa. The metal-boride interlayer was shown to be an effective diffusion barrier against elemental cobalt; migration of elemental cobalt to the surface of the interlayer was significantly reduced. A combination of glancing angle X-ray diffraction, electron dispersive spectroscopy, nanoindentation and scratch testing was used to evaluate the surface composition and material properties. An evaluation of the material properties shows that plasma enhanced chemical vapor deposited borides formed at substrate temperatures of 800 °C, 850 °C, 900 °C and 1000 °C strengthen the material by increasing the hardness and elastic modulus of cemented tungsten carbide. Additionally, these boride surface layers may offer potential for adhesion of ultra-hard carbon coatings.

  3. The growth of axially modulated p–n GaN nanowires by plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Wu, Tung-Hsien; Hong, Franklin Chau-Nan

    2013-01-01

    Due to the n-type characteristics of intrinsic gallium nitride, p-type gallium nitride (GaN) is more difficult to synthesize than n-type gallium nitride in forming the p–n junctions for optoelectronic applications. For the growth of the p-type gallium nitride, magnesium is used as the dopant. The Mg-doped GaN nanowires (NWs) have been synthesized on (111)-oriented n + -silicon substrates by plasma-enhanced chemical vapor deposition. The scanning electron microscope images showed that the GaN NWs were bent at high Mg doping levels, and the transmission electron microscope characterization indicated that single-crystalline GaN NWs grew along < 0001 > orientation. As shown by energy dispersive spectroscopy, the Mg doping levels in GaN NWs increased with increasing partial pressure of magnesium nitride, which was employed as the dopant precursor for p-GaN NW growth. Photoluminescence measurements suggested the presence of both p- and n‐type GaN NWs. Furthermore, the GaN NWs with axial p–n junctions were aligned between either two-Ni or two-Al electrodes by applying alternating current voltages. The current–voltage characteristics have confirmed the formation of axial p–n junctions in GaN nanowires. - Highlights: ► Grow axially modulated GaN nanowires by plasma-enhanced chemical vapor deposition ► Control the Mg concentration of GaN nanowires by tuning Mg 3 N 2 temperature ► Align the GaN nanowires by applying alternating current voltages between electrodes

  4. Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Johnston, Jamin M.; Catledge, Shane A.

    2016-01-01

    Graphical abstract: - Highlights: • A detailed phase analysis after PECVD boriding shows WCoB, CoB and/or W_2CoB_2. • EDS of PECVD borides shows boron diffusion into the carbide grain structure. • Nanoindentation hardness and modulus of borides is 23–27 GPa and 600–780 GPa. • Scratch testing shows hard coating with cracking at 40N and spallation at 70N. - Abstract: Strengthening of cemented tungsten carbide by boriding is used to improve the wear resistance and lifetime of carbide tools; however, many conventional boriding techniques render the bulk carbide too brittle for extreme conditions, such as hard rock drilling. This research explored the variation in metal-boride phase formation during the microwave plasma enhanced chemical vapor deposition process at surface temperatures from 700 to 1100 °C. We showed several well-adhered metal-boride surface layers consisting of WCoB, CoB and/or W_2CoB_2 with average hardness from 23 to 27 GPa and average elastic modulus of 600–730 GPa. The metal-boride interlayer was shown to be an effective diffusion barrier against elemental cobalt; migration of elemental cobalt to the surface of the interlayer was significantly reduced. A combination of glancing angle X-ray diffraction, electron dispersive spectroscopy, nanoindentation and scratch testing was used to evaluate the surface composition and material properties. An evaluation of the material properties shows that plasma enhanced chemical vapor deposited borides formed at substrate temperatures of 800 °C, 850 °C, 900 °C and 1000 °C strengthen the material by increasing the hardness and elastic modulus of cemented tungsten carbide. Additionally, these boride surface layers may offer potential for adhesion of ultra-hard carbon coatings.

  5. Structural and photoluminescence investigation on the hot-wire assisted plasma enhanced chemical vapor deposition growth silicon nanowires

    International Nuclear Information System (INIS)

    Chong, Su Kong; Goh, Boon Tong; Wong, Yuen-Yee; Nguyen, Hong-Quan; Do, Hien; Ahmad, Ishaq; Aspanut, Zarina; Muhamad, Muhamad Rasat; Dee, Chang Fu; Rahman, Saadah Abdul

    2012-01-01

    High density of silicon nanowires (SiNWs) were synthesized by a hot-wire assisted plasma enhanced chemical vapor deposition technique. The structural and optical properties of the as-grown SiNWs prepared at different rf power of 40 and 80 W were analyzed in this study. The SiNWs prepared at rf power of 40 W exhibited highly crystalline structure with a high crystal volume fraction, X C of ∼82% and are surrounded by a thin layer of SiO x . The NWs show high absorption in the high energy region (E>1.8 eV) and strong photoluminescence at 1.73 to 2.05 eV (red–orange region) with a weak shoulder at 1.65 to 1.73 eV (near IR region). An increase in rf power to 80 W reduced the X C to ∼65% and led to the formation of nanocrystalline Si structures with a crystallite size of <4 nm within the SiNWs. These NWs are covered by a mixture of uncatalyzed amorphous Si layer. The SiNWs prepared at 80 W exhibited a high optical absorption ability above 99% in the broadband range between 220 and ∼1500 nm and red emission between 1.65 and 1.95 eV. The interesting light absorption and photoluminescence properties from both SiNWs are discussed in the text. - Highlights: ► Growth of random oriented silicon nanowires using hot-wire assisted plasma enhanced chemical vapor deposition. ► Increase in rf power reduces the crystallinity of silicon nanowires. ► High density and nanocrystalline structure in silicon nanowires significant enhance the near IR light absorption. ► Oxide defects and silicon nanocrystallites in silicon nanowires reveal photoluminescence in red–orange and red regions.

  6. Chemical interaction and adhesion characteristics at the interface of metals (Cu, Ta) and low-k cyclohexane-based plasma polymer (CHexPP) films

    International Nuclear Information System (INIS)

    Kim, K.J.; Kim, K.S.; Lee, N.-E.; Choi, J.; Jung, D.

    2001-01-01

    Chemical interaction and adhesion characteristics between metals (Cu, Ta) and low-k plasma-treated cyclohexane-based plasma polymer (CHexPP) films were studied. In order to generate new functional groups that may contribute to the improvement of adhesion between metal and plasma polymer, we performed O 2 , N 2 , and H 2 /He mixture plasma treatment on the surfaces of CHexPP films. Chemical interactions at the interface between metals (Cu, Ta) and plasma-treated CHexPP films were analyzed by x-ray photoelectron spectroscopy. The effect of plasma treatment and thermal annealing on the adhesion characteristics was measured by a tape test and scratch test. The formation of new binding states on the surface of plasma-treated CHexPP films improved adhesion characteristics between metals and CHexPP films. Thermal annealing improves the adhesion property of Cu/CHexPP films, but degrades the adhesion property of Ta/CHexPP films

  7. Investigation of the surface chemical and electronic states of pyridine-capped CdSe nanocrystal films after plasma treatments using H2, O2, and Ar gases

    International Nuclear Information System (INIS)

    Wang, Seok-Joo; Kim, Hyuncheol; Park, Hyung-Ho; Lee, Young-Su; Jeon, Hyeongtag; Chang, Ho Jung

    2010-01-01

    Surface chemical bonding and the electronic states of pyridine-capped CdSe nanocrystal films were evaluated using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy before and after plasma treatments using H 2 , O 2 , and Ar gases from the viewpoint of studying the effects of surface capping organic molecules and surface oxidation. Surface capping organic molecules could be removed during the plasma treatment due to the chemical reactivity, ion energy transfer, and vacuum UV (VUV) of the plasma gases. With O 2 plasma treatment, surface capping organic molecules were effectively removed but substantial oxidation of CdSe occurred during the plasma treatment. The valence band maximum energy (E VBM ) of CdSe nanocrystal films mainly depends on the apparent size of pyridine-capped CdSe nanocrystals, which controls the interparticle distance, and also on the oxidation of CdSe nanocrystals. Cd-rich surface in O 2 and H 2 plasma treatments partially would compensate for the decrease in E VBM . After Ar plasma treatment, the smallest value of E VBM resulted from high VUV photon flux, short wavelength, and ion energy transfer. The surface bonding states of CdSe had a strong influence on the electronic structure with the efficient strip of capping molecules as well as different surface oxidations and surface capping molecule contents.

  8. Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-07-01

    Full Text Available Investigations on the wetting, solubility and chemical composition of plasma polymer thin films provide an insight into the feasibility of implementing these polymeric materials in organic electronics, particularly where wet solution processing is involved. In this study, thin films were prepared from 1-isopropyl-4-methyl-1,4-cyclohexadiene (γ-Terpinene using radio frequency (RF plasma polymerization. FTIR showed the polymers to be structurally dissimilar to the original monomer and highly cross-linked, where the loss of original functional groups and the degree of cross-linking increased with deposition power. The polymer surfaces were hydrocarbon-rich, with oxygen present in the form of O–H and C=O functional groups. The oxygen content decreased with deposition power, with films becoming more hydrophobic and, thus, less wettable. The advancing and receding contact angles were investigated, and the water advancing contact angle was found to increase from 63.14° to 73.53° for thin films prepared with an RF power of 10 W to 75 W. The wetting envelopes for the surfaces were constructed to enable the prediction of the surfaces’ wettability for other solvents. The effect of roughness on the wetting behaviour of the films was insignificant. The polymers were determined to resist solubilization in solvents commonly used in the deposition of organic semiconducting layers, including chloroform and chlorobenzene, with higher stability observed in films fabricated at higher RF power.

  9. Physico-chemical studies of laser-induced plasmas for quantitative analysis of materials in nuclear systems

    International Nuclear Information System (INIS)

    Saad, Rawad

    2014-01-01

    Laser Induced Breakdown Spectroscopy (LIBS) is a multi-elemental analysis technique very well suited for analysis in hostile environments particularly in the nuclear industry. Quantitative measurements are frequently performed on liquid or solid samples but in some cases, atypical signal behaviors were observed in the LIBS experiment. To avoid or minimize any impact on measurement accuracy, it is necessary to improve the understanding of these phenomena. In the framework of a three-year PhD thesis, the objective was to study the chemical reactions occurring within laser-generated plasma in a LIBS analysis. Experiments on a model material (pure aluminum sample) highlighted the dynamics of molecular recombination according to different ambient gas. The temporal evolution of Al I atomic emission lines and molecular bands of AlO and AlN were studied. A collisional excitation effect was identified for a peculiar electronic energy level of aluminum in the case of a nitrogen atmosphere. This effect disappeared in air. The aluminum plasma was also imaged during its expansion under the different atmospheres in order to localize the areas in which the molecular recombination process takes place. Spectacular particle projections have been highlighted. (author) [fr

  10. A simple method to deposit palladium doped SnO2 thin films using plasma enhanced chemical vapor deposition technique

    International Nuclear Information System (INIS)

    Kim, Young Soon; Wahab, Rizwan; Shin, Hyung-Shik; Ansari, S. G.; Ansari, Z. A.

    2010-01-01

    This work presents a simple method to deposit palladium doped tin oxide (SnO 2 ) thin films using modified plasma enhanced chemical vapor deposition as a function of deposition temperature at a radio frequency plasma power of 150 W. Stannic chloride (SnCl 4 ) was used as precursor and oxygen (O 2 , 100 SCCM) (SCCM denotes cubic centimeter per minute at STP) as reactant gas. Palladium hexafluroacetyleacetonate (Pd(C 5 HF 6 O 2 ) 2 ) was used as a precursor for palladium. Fine granular morphology was observed with tetragonal rutile structure. A peak related to Pd 2 Sn is observed, whose intensity increases slightly with deposition temperature. Electrical resistivity value decreased from 8.6 to 0.9 mΩ cm as a function of deposition temperature from 400 to 600 deg. C. Photoelectron peaks related to Sn 3d, Sn 3p3, Sn 4d, O 1s, and C 1s were detected with varying intensities as a function of deposition temperature.

  11. Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

    Science.gov (United States)

    DeCoste, Jared B.; Peterson, Gregory W.

    2013-01-01

    Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials. PMID:24145623

  12. Vertically aligned Si nanocrystals embedded in amorphous Si matrix prepared by inductively coupled plasma chemical vapor deposition (ICP-CVD)

    Energy Technology Data Exchange (ETDEWEB)

    Nogay, G. [Department of Physics, Middle East Technical University (METU), Ankara 06800 (Turkey); Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Saleh, Z.M., E-mail: zaki.saleh@aauj.edu [Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Department of Physics, Arab American University–Jenin (AAUJ), Jenin, Palestine (Country Unknown); Özkol, E. [Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Department of Chemical Engineering, Middle East Technical University (METU), Ankara 06800 (Turkey); Turan, R. [Department of Physics, Middle East Technical University (METU), Ankara 06800 (Turkey); Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey)

    2015-06-15

    Highlights: • Inductively-coupled plasma is used for nanostructured silicon at room temperature. • Low temperature deposition allows device processing on various substrates. • Deposition pressure is the most effective parameter in controlling nanostructure. • Films consist of quantum dots in a-Si matrix and exhibit columnar vertical growth. • Films are porous to oxygen infusion along columnar grain boundaries. - Abstract: Vertically-aligned nanostructured silicon films are deposited at room temperature on p-type silicon wafers and glass substrates by inductively-coupled, plasma-enhanced chemical vapor deposition (ICPCVD). The nanocrystalline phase is achieved by reducing pressure and increasing RF power. The crystalline volume fraction (X{sub c}) and the size of the nanocrystals increase with decreasing pressure at constant power. Columnar growth of nc-Si:H films is observed by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The films exhibit cauliflower-like structures with high porosity that leads to slow but uniform oxidation after exposure to air at room temperature. Films deposited at low pressures exhibit photoluminescence (PL) signals that may be deconvoluted into three distinct Gaussian components: 760–810, 920–935, and 990–1000 nm attributable to the quantum confinement and interface defect states. Hydrogen dilution is manifested in significant enhancement of the PL, but it has little effect on the nanocrystal size and X{sub c}.

  13. Complete chemical analysis of produced water by modern inductively coupled plasma spectroscopy (ICP)

    Energy Technology Data Exchange (ETDEWEB)

    Graham, G M; Sorbie, K S; Johnston, A; Boak, L S

    1997-12-31

    ICP (Inductively Coupled Plasma) spectroscopy is recognised as a very effective tool for monitoring ion compositions in many different waters. It has also been used by a number of laboratories to determine residual levels of phosphonate (PH) scale inhibitors in produced waters, based on phosphorus content. Until recently, it had not been used effectively to monitor phosphino-polycarboxylate (PPCA) returns. Large errors had frequently been observed where it had been applied. The poor detection limits and accuracy obtained for PPCA inhibitors relates to much lower amount of phosphorus present when compared with a typical phosphonate inhibitor. This paper demonstrates the effectiveness of IPC detection for PPCA and other phosphorus containing inhibitors by the use of modern instruments without the need of pre-treatment. 6 refs., 3 figs., 10 tabs.

  14. Gas-discharge plasma processes for surface modification and conversion of chemical substances. Application for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, K.; Meyer, D.; Rohland, B.; Heintze, M.; Zahn, R.J.; Hannemann, M.; Meusinger, J.; Ohl, A. [Institute of Non-Thermal Plasma Physics, Greifswald (Germany)]|[Gesellschaft fuer Angewandte Technik mbH Greifswald (Germany)]|[GAPC, Adam Opel AG, IPC, Ruesselsheim (Germany)

    2001-07-01

    The potential of plasma processes towards hydrogen and fuel cell technology will be demonstrated by two examples with preliminary results: 1. plasma modification of polymer electrolyte membranes for direct methanol fuel cells, and 2. plasma supported steam reforming.

  15. 8th Symposium on elementary processes and chemical reactions in low temperature plasma. Pt. 1 and 2

    International Nuclear Information System (INIS)

    Morvova, M.

    1990-11-01

    The document contains invited papers on low temperature plasma physics and its application. Among them, 9 papers deal with the experimental and theoretical investigation and modelling of elementary plasma processes and particle kinematics in electric discharges of various type and purpose. Each of the following 3 papers presents a survey of some advanced plasma technology, as are laser plasma chemistry, plasma production of diamond-like carbon films and of special fine powders. The ionized Van der Waals clusters, shock waves in interplanetary plasma, and plasma acceleration in electromagnetic plasma launchers are the topics of the remaining three papers. (J.U.)

  16. SiC nanofibers grown by high power microwave plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Honda, Shin-ichi; Baek, Yang-Gyu; Ikuno, Takashi; Kohara, Hidekazu; Katayama, Mitsuhiro; Oura, Kenjiro; Hirao, Takashi

    2003-01-01

    Silicon carbide (SiC) nanofibers have been synthesized on Si substrates covered by Ni thin films using high power microwave chemical vapor deposition (CVD). Characterization using transmission electron microscopy (TEM) combined with electron energy-dispersive X-ray spectroscopy (EDX) revealed that the resultant fibrous nanostructures were assigned to β-SiC with high crystallinity. The formation of SiC nanofibers can be explained by the vapor liquid solid (VLS) mechanism in which precipitation of SiC occurs from the supersaturated Ni nanoparticle containing Si and C

  17. Effects of chemical sympathectomy on the increases in plasma catecholamines and dopamine-beta-hydroxylase induced by forced immobilization and insulin-induced hypoglycemia: origin and fate of plasma dopamine-beta-hydroxylase.

    Science.gov (United States)

    Israel, A S; Barbella, Y R; Cubeddu, L X

    1982-06-01

    The effect of acute stresses on plasma norepinephrine, epinephrine and dopamine-beta-hydroxylase (DBH) were evaluated in control and 6-hydroxydopamine-treated, awake cannulated guinea pigs. Forced immobolization for 1 hr caused a 3- and 5-fold increase in plasma DBH and norepinephrine, respectively. Pretreatment with 6-hydroxydopamine (23 mg/kg b.wt.i.a., 72 and 48 hr before stress) reduced by 70% the increase in plasma DBH and totally prevented the rise in plasma catecholamines evoked by the restraining stress. Injection of insulin (5 U/kg b.wt.i.a.) induced a 60% decrease in blood glucose, a 1-fold increase in plasma DBH and a selective 4-fold increase in plasma epinephrine; these effects were not modified by chemical sympathectomy. Our results indicate that forced immobilization and hypoglycemia produce a preferential activation of the sympathetic postganglionic nerves and of the adrenal medulla, respectively, and that in guinea pigs both stresses increase plasma DBH. The kinetics of disappearance of plasma DBH were studied after subjecting the guinea pigs for 1 hr to forced immobilization. Although 7 of 12 animals showed a biphasic rate of fall of plasma DBH, in each case there was a rapid initial fall possibly due to the "distribution" of the enzyme with a T1/2 of 1.65 hr. Similar findings were observed in 6-hydroxydopamine-treated guinea pigs. These results suggest that the distribution of DBH is the most important process in reducing the augmented plasma DBH levels elicited by a short-term stress and that this process is not dependent on the integrity of the sympathetic nerves nor on the adrenal or sympathetic origin of the enzyme. This study supports the view that the ratio, content of releasable DBH present in sympathetic nerves and adrenal glands/total circulating pool of DBH, is the factor that determines whether an increase in plasma DBH would occur in animals exposed to an acute stress.

  18. Plasma-activation of tap water using DBD for agronomy applications: Identification and quantification of long lifetime chemical species and production/consumption mechanisms.

    Science.gov (United States)

    Judée, F; Simon, S; Bailly, C; Dufour, T

    2018-04-15

    Cold atmospheric plasmas are weakly ionized gases that can be generated in ambient air. They produce energetic species (e.g. electrons, metastables) as well as reactive oxygen species, reactive nitrogen species, UV radiations and local electric field. Their interaction with a liquid such as tap water can hence change its chemical composition. The resulting "plasma-activated liquid" can meet many applications, including medicine and agriculture. Consequently, a complete experimental set of analytical techniques dedicated to the characterization of long lifetime chemical species has been implemented to characterize tap water treated using cold atmospheric plasma process and intended to agronomy applications. For that purpose, colorimetry and acid titrations are performed, considering acid-base equilibria, pH and temperature variations induced during plasma activation. 16 species are quantified and monitored: hydroxide and hydronium ions, ammonia and ammonium ions, orthophosphates, carbonate ions, nitrite and nitrate ions and hydrogen peroxide. The related consumption/production mechanisms are discussed. In parallel, a chemical model of electrical conductivity based on Kohlrausch's law has been developed to simulate the electrical conductivity of the plasma-activated tap water (PATW). Comparing its predictions with experimental measurements leads to a narrow fitting, hence supporting the self-sufficiency of the experimental set, I.e. the fact that all long lifetime radicals of interest present in PATW are characterized. Finally, to evaluate the potential of cold atmospheric plasmas for agriculture applications, tap water has been daily plasma-treated to irrigate lentils seeds. Then, seedlings lengths have been measured and compared with untreated tap water, showing an increase as high as 34.0% and 128.4% after 3 days and 6 days of activation respectively. The interaction mechanisms between plasma and tap water are discussed as well as their positive synergy on

  19. Ge-rich islands grown on patterned Si substrates by low-energy plasma-enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Bollani, M; Fedorov, A; Chrastina, D; Sordan, R; Picco, A; Bonera, E

    2010-01-01

    Si 1-x Ge x islands grown on Si patterned substrates have received considerable attention during the last decade for potential applications in microelectronics and optoelectronics. In this work we propose a new methodology to grow Ge-rich islands using a chemical vapour deposition technique. Electron-beam lithography is used to pre-pattern Si substrates, creating material traps. Epitaxial deposition of thin Ge films by low-energy plasma-enhanced chemical vapour deposition then leads to the formation of Ge-rich Si 1-x Ge x islands (x > 0.8) with a homogeneous size distribution, precisely positioned with respect to the substrate pattern. The island morphology was characterized by atomic force microscopy, and the Ge content and strain in the islands was studied by μRaman spectroscopy. This characterization indicates a uniform distribution of islands with high Ge content and low strain: this suggests that the relatively high growth rate (0.1 nm s -1 ) and low temperature (650 deg. C) used is able to limit Si intermixing, while maintaining a long enough adatom diffusion length to prevent nucleation of islands outside pits. This offers the novel possibility of using these Ge-rich islands to induce strain in a Si cap.

  20. Ge-rich islands grown on patterned Si substrates by low-energy plasma-enhanced chemical vapour deposition.

    Science.gov (United States)

    Bollani, M; Chrastina, D; Fedorov, A; Sordan, R; Picco, A; Bonera, E

    2010-11-26

    Si(1-x)Ge(x) islands grown on Si patterned substrates have received considerable attention during the last decade for potential applications in microelectronics and optoelectronics. In this work we propose a new methodology to grow Ge-rich islands using a chemical vapour deposition technique. Electron-beam lithography is used to pre-pattern Si substrates, creating material traps. Epitaxial deposition of thin Ge films by low-energy plasma-enhanced chemical vapour deposition then leads to the formation of Ge-rich Si(1-x)Ge(x) islands (x > 0.8) with a homogeneous size distribution, precisely positioned with respect to the substrate pattern. The island morphology was characterized by atomic force microscopy, and the Ge content and strain in the islands was studied by μRaman spectroscopy. This characterization indicates a uniform distribution of islands with high Ge content and low strain: this suggests that the relatively high growth rate (0.1 nm s(-1)) and low temperature (650 °C) used is able to limit Si intermixing, while maintaining a long enough adatom diffusion length to prevent nucleation of islands outside pits. This offers the novel possibility of using these Ge-rich islands to induce strain in a Si cap.

  1. Ti-doped hydrogenated diamond like carbon coating deposited by hybrid physical vapor deposition and plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Lee, Na Rae; Sle Jun, Yee; Moon, Kyoung Il; Sunyong Lee, Caroline

    2017-03-01

    Diamond-like carbon films containing titanium and hydrogen (Ti-doped DLC:H) were synthesized using a hybrid technique based on physical vapor deposition (PVD) and plasma enhanced chemical vapor deposition (PECVD). The film was deposited under a mixture of argon (Ar) and acetylene gas (C2H2). The amount of Ti in the Ti-doped DLC:H film was controlled by varying the DC power of the Ti sputtering target ranging from 0 to 240 W. The composition, microstructure, mechanical and chemical properties of Ti-doped DLC:H films with varying Ti concentrations, were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nano indentation, a ball-on-disk tribometer, a four-point probe system and dynamic anodic testing. As a result, the optimum composition of Ti in Ti-doped DLC:H film using our hybrid method was found to be a Ti content of 18 at. %, having superior electrical conductivity and high corrosion resistance, suitable for bipolar plates. Its hardness value was measured to be 25.6 GPa with a low friction factor.

  2. Growth and characterization of stoichiometric BCN films on highly oriented pyrolytic graphite by radiofrequency plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mannan, Md. Abdul, E-mail: amannan75@yahoo.co [Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo, Saga 840-8502 (Japan); Synchrotron Radiation Research Unit, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Noguchi, Hideyuki; Kida, Tetsuya; Nagano, Masamitsu [Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, 1 Honjo, Saga 840-8502 (Japan); Hirao, Norie; Baba, Yuji [Synchrotron Radiation Research Unit, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

    2010-05-31

    Hexagonal boron carbonitride (h-BCN) hybrid films have been synthesized on highly oriented pyrolytic graphite by radiofrequency plasma enhanced chemical vapor deposition using tris-(dimethylamino)borane as a single-source molecular precursor. The films were characterized by X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopic measurements. XPS measurement showed that the B atoms were bonded to C and N atoms to form the sp{sup 2}-B-C-N atomic hybrid chemical environment. The atomic composition estimated from the XPS of the typical sample was found to be almost B{sub 1}C{sub 1}N{sub 1}. NEXAFS spectra of the B K-edge and the N K-edge had the peaks due to the {pi}* and {sigma}* resonances of sp{sup 2} hybrid orbitals implying the existence of the sp{sup 2} hybrid configurations of h-BCN around the B atoms. The G band at 1592 and D band at 1352 cm{sup -1} in the Raman spectra also suggested the presence of the graphite-like sp{sup 2}-B-C-N atomic hybrid bonds. The films consisted of micrometer scale crystalline structure of around 10 {mu}m thick has been confirmed by the field emission scanning electron microscopy.

  3. Numerical model of the plasma formation at electron beam welding

    Energy Technology Data Exchange (ETDEWEB)

    Trushnikov, D. N., E-mail: trdimitr@yandex.ru [The Department for Applied Physics, Perm National Research Polytechnic University, Perm 614990 (Russian Federation); The Department for Welding Production and Technology of Constructional Materials, Perm National Research Polytechnic University, Perm 614990 (Russian Federation); Mladenov, G. M., E-mail: gmmladenov@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, 1784 Sofia (Bulgaria); Technology Centre of Electron Beam and Plasma Technologies and Techniques, 68-70 Vrania, ap.10, Banishora, 1309 Sofia (Bulgaria)

    2015-01-07

    The model of plasma formation in the keyhole in liquid metal as well as above the electron beam welding zone is described. The model is based on solution of two equations for the density of electrons and the mean electron energy. The mass transfer of heavy plasma particles (neutral atoms, excited atoms, and ions) is taken into account in the analysis by the diffusion equation for a multicomponent mixture. The electrostatic field is calculated using the Poisson equation. Thermionic electron emission is calculated for the keyhole wall. The ionization intensity of the vapors due to beam electrons and high-energy secondary and backscattered electrons is calibrated using the plasma parameters when there is no polarized collector electrode above the welding zone. The calculated data are in good agreement with experimental data. Results for the plasma parameters for excitation of a non-independent discharge are given. It is shown that there is a need to take into account the effect of a strong electric field near the keyhole walls on electron emission (the Schottky effect) in the calculation of the current for a non-independent discharge (hot cathode gas discharge). The calculated electron drift velocities are much bigger than the velocity at which current instabilities arise. This confirms the hypothesis for ion-acoustic instabilities, observed experimentally in previous research.

  4. A hybrid plasma-chemical system for high-NOx flue gas treatment

    Science.gov (United States)

    Chmielewski, Andrzej G.; Zwolińska, Ewa; Licki, Janusz; Sun, Yongxia; Zimek, Zbigniew; Bułka, Sylwester

    2018-03-01

    The reduction of high concentrations of NOx and SO2 from simulated flue gas has been studied. Our aim was to optimise energy consumption for NOx and SO2 removal from off-gases from a diesel generator using heavy fuel oil. A hybrid process: electron beam (EB) plasma and wet scrubber has been applied. A much higher efficiency of NOx and SO2 removal was achieved in comparison to dry, ammonia free, electron beam flue gas treatment (EBFGT). A recorded removal from a concentration of 1500 ppm NOx reached 49% at a low dose of 6.5 kGy, while only 2% NOx was removed at the same dose if EB only was applied. For SO2, removal efficiency at a dose of 6.5 kGy increased from 15% (EB only) to 84% when sea water was used as a wet scrubber agent for 700 ppm SO2. The results of this study indicate that EB combined with wet scrubber is a very promising technology to be applied for removal of high concentrations of NOx and SO2 emitted from diesel engines operated e.g. on cargo ships, which are the main sources of SO2 and NOx pollution along their navigation routes.

  5. Comparison of diamond growth with different gas mixtures in microwave plasma asssited chemical vapor deposition (MWCVD

    Directory of Open Access Journals (Sweden)

    Corat Evaldo J.

    2003-01-01

    Full Text Available In this work we study the influence of oxygen addition to several halocarbon-hydrogen gas systems. Diamond growth have been performed in a high power density MWCVD reactor built in our laboratory. The growth experiments are monitored by argon actinometry as a reference to plasma temperature and atomic hydrogen production, and by mass spectrometry to compare the exhaust gas composition. Atomic hydrogen actinometry revealed that the halogen presence in the gas phase is responsible for a considerable increase of atomic hydrogen concentration in the gas phase. Mass spectrometry shows similar results for all gas mixtures tested. Growth studies with oxygen addition to CF4/H2, CCl4/H2, CCl2F2/H2 and CH3Cl/H2 reveals that oxygen increases the carbon solubility in the gas phase but no better diamond growth conditions were found. Halogens are not, per se, eligible for diamond growth. All the possible advantages, as the higher production of atomic hydrogen, have been suppressed by the low carbon solubility in the gas phase, even when oxygen is added. The diamond growth with small amount of CF4 added to CH4/H2 mixture is not aggressive to the apparatus but brings several advantages to the process.

  6. Physical and chemical interactions at the interface between atmospheric pressure plasmas and aqueous solutions

    Science.gov (United States)

    Lindsay, Alexander; Byrns, Brandon; Knappe, Detlef; Graves, David; Shannon, Steven

    2014-10-01

    Transport and reactions of charged species, neutrals, and photons at the interface between plasmas and liquids must be better quantified. The work presented here combines theoretical and experimental investigations of conditions in the gas and liquid phases in proximity to the interface for various discharges. OES is used to determine rotational and vibrational temperatures of OH, NO, and N2+; the relationship between these temperatures that characterize the distribution of internal energy states and gas and electron kinetic temperatures is considered. The deviation of OH rotational states from equilibrium under high humidity conditions is also presented. In contradiction with findings of other groups, high energy rotational states appear to become underpopulated with increasing humidity. In the aqueous phase, concentrations of longer-lived species such as nitrate, nitrite, hydrogen peroxide, and ozone are determined using ion chromatography and colorimetric methods. Spin-traps and electron paramagnetic resonance (EPR) are investigated for characterization of short-lived aqueous radicals like OH, O2-, NO, and ONOO-. Finally, experimental results are compared to a numerical model which couples transport and reactions within and between the bulk gas and liquid phases.

  7. The Performance Improvement of N2 Plasma Treatment on ZrO2 Gate Dielectric Thin-Film Transistors with Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition IGZO Channel.

    Science.gov (United States)

    Wu, Chien-Hung; Huang, Bo-Wen; Chang, Kow-Ming; Wang, Shui-Jinn; Lin, Jian-Hong; Hsu, Jui-Mei

    2016-06-01

    The aim of this paper is to illustrate the N2 plasma treatment for high-κ ZrO2 gate dielectric stack (30 nm) with indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs). Experimental results reveal that a suitable incorporation of nitrogen atoms could enhance the device performance by eliminating the oxygen vacancies and provide an amorphous surface with better surface roughness. With N2 plasma treated ZrO2 gate, IGZO channel is fabricated by atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) technique. The best performance of the AP-PECVD IGZO TFTs are obtained with 20 W-90 sec N2 plasma treatment with field-effect mobility (μ(FET)) of 22.5 cm2/V-s, subthreshold swing (SS) of 155 mV/dec, and on/off current ratio (I(on)/I(off)) of 1.49 x 10(7).

  8. Quantum chemical estimation of sorption/desorption of H{sub 2} and H{sub 2}O (gas) at the plasma-wall interface

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaki, Shinya; Tsushima, Satoru; Tanaka, Masataka; Umemura, Yasuhiro [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    By using MOPAC Code, we estimated the charge density of SiO{sub 2}-Al{sub 2}O{sub 3}-SiO{sub 2} metal oxide. We could find that the such quantum chemical calculation is a fruitful tool for understanding the plasma-wall interactions from the microscopic point of view. (author)

  9. Sensing performance of plasma-enhanced chemical vapor deposition SiC-SiO2-SiC horizontal slot waveguides

    NARCIS (Netherlands)

    Pandraud, G.; Margallo-Balbas, E.; Sarro, P.M.

    2012-01-01

    We have studied, for the first time, the sensing capabilities of plasma-enhanced chemical vapor deposition (PECVD) SiC-SiO2-SiC horizontal slot waveguides. Optical propagation losses were measured to be 23.9 dB?cm for the quasi-transverse magnetic mode. To assess the potential of this device as a

  10. Alternative electro-chemically based processing routes for joining of plasma facing components

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, Wolfgang, E-mail: wolfgang.krauss@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Materials Research III, Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen (Germany); Lorenz, Julia; Holstein, Nils; Konys, Juergen [Karlsruhe Institute of Technology (KIT), Institute for Materials Research III, Hermann-von-Helmholtz-Platz 1 76344 Eggenstein-Leopoldshafen (Germany)

    2011-10-15

    Tungsten is considered in fusion technology as functional and structural material in the area of blanket and divertor for future application in DEMO. The KIT design of a He-cooled divertor includes joints between W and W-alloys as well as of W with Eurofer-steel. The main challenges range from expansion mismatch problem for tungsten/steel joints over metallurgical reactions with brittle phase formation to crack stopping ability and excellent surface wetting. These requirements were only met partly and insufficiently in the past e.g. by direct Cu-casting of tungsten onto steel. Both, the joining needs and the observed failure scenarios of conventionally joined components initiated the development of improved joining technologies based on electro-chemical processing routes. As electrolytes aqueous and aprotic, water free, system are integrated into this development line. In the first step principle requirements are presented to guarantee a reproducible and adherent deposition of scales based on Ni and Cu acting as inter layers and filler, respectively, to generate a real metallurgical bonding as demonstrate by 1100 deg. C joining tests. The development field aprotic systems based on ionic liquids is discussed with respect to enable development of refractory metal based fillers with focus high temperature W-W brazing.

  11. Obtention of selective membranes for water and hydrophobic liquids by plasma enhanced chemical vapor deposition on porous substrates

    International Nuclear Information System (INIS)

    Bankovic, P.; Demarquette, N.R.; Silva, M.L.P. da

    2004-01-01

    In this work, the possibility of obtaining selective membranes for water and hydrophobic liquids by plasma enhanced chemical vapor deposition (PECVD) of hexamethyldisilazane (HMDS) or double layers of HMDS and n-hexane on porous substrates using a capacitive plasma reactor was investigated. The porous substrates used were paper filter, diatomite and polyester textiles. The films were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and contact angle measurements. The membranes obtained were characterized by the Cobb test. Their efficiency to separate hydrocarbon compounds from water was evaluated through filtration experiments and Karl-Fischer titration tests. The reagents used in the filtration experiments were: chloroform, n-hexane, n-heptane, ethyl ether, benzene and diesel. XPS analysis showed that Si, N, C and O were present at the surface of the film. C peak was dominant in the double layer film spectra. C-H n , CH 2 , Si-H, Si-CH 3 , N-H, Si-CH 2 -Si, Si-N-Si and Si-C bonds were identified in both types of the films by ATR-FTIR. The relative intensities of the corresponding peaks in the two spectra were different. The XPS and FTIR results indicated that C was most likely present in a CH n form at the surface of double layer film. The average contact angles formed by drops of water on the film surface ranged from 135 deg. to 155 deg. . Water adsorption measured by Cobb test decreased from average values ranging from 300 to 9000 g m -2 (for nonmodified surfaces) to values ranging from 0 to 20 g m -2 (for treated surfaces). The Karl-Fischer titration indicated that between 90 and 1000 ppm (depending on the reagent used) of water remained in the hydrocarbon compound after filtration

  12. Shock tube experiments on nitromethane and Promotion of chemical reactions by non-thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Seljeskog, Morten

    2002-06-01

    This dissertation was undertaken to study two different subjects both related to molecular decomposition by applying a shock tube and non-thermal plasma to decompose selected hydrocarbons. The first approach to molecular decomposition concerned thermal decomposition and oxidation of highly diluted nitromethane (NM) in a shock tube. Reflected shock tube experiments on NM decomposition, using mixtures of 0.2 to 1.5 vol% NM in nitrogen or argon were performed over the temperature range 850-1550 K and pressure range 190-900 kPa, with 46 experiments diluted in nitrogen and 44 diluted in argon. By residual error analysis of the measured decomposition profiles it was found that NM decomposition (CH{sub 3}NO{sub 2} + M {yields} CH{sub 3} + NO{sub 2} + M, where M = N{sub 2} /Ar) corresponds well to a law of first order. Arrhenius expressions corresponding to NM diluted either in N{sub 2} or in Ar were found as k{sub N2} = 10{sup 17.011} * exp(- 182.6 kJ/mole / R*T) and k{sub Ar} = 10{sup 17.574}*exp(-207 kJ/mole / R*T ) , respectively. A new reaction mechanism was then proposed, based on new experimental data for NM decomposition both in Ar and N{sub 2} and on three previously developed mechanisms. The new mechanism predicts well the decomposition of NM diluted in both N{sub 2} and Ar within the pressure and temperature range covered by the experiments. In parallel to, and following the decomposition experiments, oxidative experiments on the ignition delay times of NM/O{sub 2}/Ar mixtures were investigated over high temperature and low to high pressure ranges. These experiments were carried out with eight different mixtures of gaseous NM and oxygen diluted in argon, with pressures ranging between 44.3-600 kPa, and temperatures ranging between 842-1378 K. The oxidation experiments were divided into different categories according to the type of decomposition signals achieved. For signals with and without emission, the apparent quasi

  13. Effects of the addition of blood plasma proteins on physico-chemical properties of emulsion-type pork sausage during cold storage.

    Science.gov (United States)

    Kim, Sungho; Jin, Sangkeun; Choi, Jungseok

    2017-10-01

    Most slaughter blood is discarded, resulting in problems related to costs for wastewater disposal and environmental pollution. However, animal blood contains various proteins such as albumin, globulin and globin and can be used as a natural emulsifier, stabiliser and colour additive. Thus, this study was carried out to investigate the effect of blood plasma proteins on the physico-chemical properties of emulsion-type pork sausages stored at 4°C over 5 weeks. The emulsion-type pork sausages with plasma powders had higher pH than the other treatments during week 5, and higher shear force than the control (P binder for the production of excellent meat products compared to other binders. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Effect of growth interruptions on TiO{sub 2} films deposited by plasma enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li, D., E-mail: dyli@yzu.edu.cn [College of Mechanical Engineering, Yangzhou University, Yangzhou, 225127 (China); Goullet, A. [Institut des Matériaux Jean Rouxel (IMN), UMR CNRS 6502, 2 rue de la Houssinière, 44322, Nantes (France); Carette, M. [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré, 59652, Villeneuve d' Ascq (France); Granier, A. [Institut des Matériaux Jean Rouxel (IMN), UMR CNRS 6502, 2 rue de la Houssinière, 44322, Nantes (France); Landesman, J.P. [Institut de Physique de Rennes, UMR CNRS 6251, 263 av. Général Leclerc, 35042, Rennes (France)

    2016-10-01

    TiO{sub 2} films of ∼300 nm were deposited at low temperature (<140 °C) and pressure (0.4 Pa) using plasma enhanced chemical vapour deposition at the floating potential (V{sub f}) or the substrate self-bias voltage (V{sub b}) of −50 V. The impact of growth interruptions on the morphology, microstructure and optical properties of the films was investigated. The interruptions were carried out by stopping the plasma generation and gas injection once the increase of the layer thickness during each deposition step was about ∼100 nm. In one case of V{sub f}, the films of ∼300 nm exhibit a columnar morphology consisting of a bottom dense layer, an intermediate gradient layer and a top roughness layer. But the growth interruptions result in an increase of the dense layer thickness and a decrease of surface roughness. The film inhomogeneity has been identified by the in-situ real-time evolution of the kinetic ellipsometry (KE) parameters and the modeling process of spectroscopic ellipsometry (SE). The discrepancy of the refractive index measured by SE between bottom and upper layers can be reduced by growth interruptions. In the other case of V{sub b} = −50 V, the films exhibit a more compact arrangement which is homogeneous along the growth direction as confirmed by KE and SE. Both of Fourier transform infrared spectra and X-ray diffraction illustrate a phase transformation from anatase to rutile with the bias of −50 V, and also evidenced on the evolution of the refractive index dispersion curves. And a greatly increase of the refractive indice in the transparent range can be identified. However, the growth interruptions seem to have no influence on the morphology and optical properties in this case. - Highlights: • TiO{sub 2} films deposited by plasma processes at low temperature and pressure. • Influence of growth interruptions on structural and optical properties. • In-situ real-time ellipsometry measurements on film properties. • Structural and

  15. Low-temperature synthesis of diamond films by photoemission-assisted plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kawata, Mayuri, E-mail: kawata@mail.tagen.tohoku.ac.jp; Ojiro, Yoshihiro; Ogawa, Shuichi; Takakuwa, Yuji [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Masuzawa, Tomoaki; Okano, Ken [International Christian University, 3-10-2 Osawa, Mitaka 181-8585 (Japan)

    2014-03-15

    Photoemission-assisted plasma-enhanced chemical vapor deposition (PA-PECVD), a process in which photoelectrons emitted from a substrate irradiated with ultraviolet light are utilized as a trigger for DC discharge, was investigated in this study; specifically, the DC discharge characteristics of PA-PECVD were examined for an Si substrate deposited in advance through hot-filament chemical vapor deposition with a nitrogen-doped diamond layer of thickness ∼1 μm. Using a commercially available Xe excimer lamp (hν = 7.2 eV) to illuminate the diamond surface with and without hydrogen termination, the photocurrents were found to be 3.17 × 10{sup 12} and 2.11 × 10{sup 11} electrons/cm{sup 2}/s, respectively. The 15-fold increase in photocurrent was ascribed to negative electron affinity (NEA) caused by hydrogen termination on the diamond surfaces. The DC discharge characteristics revealed that a transition bias voltage from a Townsend-to-glow discharge was considerably decreased because of NEA (from 490 to 373 V for H{sub 2} gas and from 330 to 200 V for Ar gas), enabling a reduction in electric power consumption needed to synthesize diamond films through PA-PECVD. In fact, the authors have succeeded in growing high-quality diamond films of area 2.0 cm{sup 2} at 540 °C with a discharge power of only 1.8 W, plasma voltage of 156.4 V, and discharge current of 11.7 mA under the glow discharge of CH{sub 4}/H{sub 2}/Ar mixed gases. In addition to having only negligible amounts of graphite and amorphous carbon, the diamond films exhibit a relatively high diamond growth rate of 0.5 μm/h at temperatures as low as 540 °C, which is attributed to Ar{sup +} ions impinging on the diamond surface, and causing the removal of hydrogen atoms from the surface through sputtering. This process leads to enhanced CH{sub x} radical adsorption, because the sample was applied with a negative potential to accelerate photoelectrons in PA-PECVD.

  16. Experimental study of a RF plasma source with helicon configuration in the mix Ar/H_2. Application to the chemical etching of carbon materials surfaces in the framework of the plasma-wall interactions studies of ITER's divertor

    International Nuclear Information System (INIS)

    Bieber, T.

    2012-01-01

    The issue of the interaction wall-plasma is important in thermonuclear devices. The purpose of this work is to design a very low pressure atomic plasma source in order to study chemical etching of carbon surfaces in the same conditions as edge plasma in tokamaks. The experimental work has consisted in 2 stages: first, the characterisation of the new helicon configuration reactor developed for this research and secondly the atomic hydrogen source used for the chemical etching. The first chapter recalls what thermonuclear fusion is. The helicon configuration reactor as well as its diagnostics (optical emission spectroscopy, laser induced fluorescence - LIF, and Langmuir probe) are described in the second chapter. The third chapter deals with the different coupling modes (RF power and plasma) identified in pure argon plasmas and how they are obtained by setting experimental parameters such as injected RF power, magnetic fields or pressure. The fourth chapter is dedicated to the study of the difference in behavior between the electronic density and the relative density of metastable Ar"+ ions. The last chapter presents the results in terms of mass losses of the carbon material surfaces obtained with the atomic hydrogen source. (A.C.)

  17. Sputtering yields and surface chemical modification of tin-doped indium oxide in hydrocarbon-based plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hu; Karahashi, Kazuhiro; Hamaguchi, Satoshi, E-mail: hamaguch@ppl.eng.osaka-u.ac.jp [Center for Atomic and Molecular Technologies, Osaka University, Yamadaoka 2-1, Suita 565-0871 (Japan); Fukasawa, Masanaga; Nagahata, Kazunori; Tatsumi, Tetsuya [Device and Material R& D Group, RDS Platform, Sony Corporation, Kanagawa 243-0014 (Japan)

    2015-11-15

    Sputtering yields and surface chemical compositions of tin-doped indium oxide (or indium tin oxide, ITO) by CH{sup +}, CH{sub 3}{sup +}, and inert-gas ion (He{sup +}, Ne{sup +}, and Ar{sup +}) incidence have been obtained experimentally with the use of a mass-selected ion beam system and in-situ x-ray photoelectron spectroscopy. It has been found that etching of ITO is chemically enhanced by energetic incidence of hydrocarbon (CH{sub x}{sup +}) ions. At high incident energy incidence, it appears that carbon of incident ions predominantly reduce indium (In) of ITO and the ITO sputtering yields by CH{sup +} and CH{sub 3}{sup +} ions are found to be essentially equal. At lower incident energy (less than 500 eV or so), however, a hydrogen effect on ITO reduction is more pronounced and the ITO surface is more reduced by CH{sub 3}{sup +} ions than CH{sup +} ions. Although the surface is covered more with metallic In by low-energy incident CH{sub 3}{sup +} ions than CH{sup +} ions and metallic In is in general less resistant against physical sputtering than its oxide, the ITO sputtering yield by incident CH{sub 3}{sup +} ions is found to be lower than that by incident CH{sup +} ions in this energy range. A postulation to account for the relation between the observed sputtering yield and reduction of the ITO surface is also presented. The results presented here offer a better understanding of elementary surface reactions observed in reactive ion etching processes of ITO by hydrocarbon plasmas.

  18. Chemical stability and osteogenic activity of plasma-sprayed boron-modified calcium silicate-based coatings.

    Science.gov (United States)

    Lu, Xiang; Li, Kai; Xie, Youtao; Huang, Liping; Zheng, Xuebin

    2016-11-01

    In recent years, CaSiO 3 bio-ceramic coatings have attracted great attention because of their good bioactivity. However, their high degradation rates in physiological environment restrict their practical applications. In this work, boron-modified CaSiO 3 ceramic (Ca 11 Si 4 B 2 O 22 , B-CS) coating was developed on Ti substrates by plasma-spraying technique attempting to obtain enhanced chemical stability and osteogenic activity. The B-CS coating possessed significantly increased chemical stability due to the introduction of boron and consequently the modified crystal structure, while maintaining good bioactivity. Scanning electron microscope and immunofluorescence studies showed that better cellular adhesion and extinctive filopodia-like processes were observed on the B-CS coating. Compared with the pure CaSiO 3 (CS) coating, the B-CS coating promoted MC3T3-E1 cells attachment and proliferation. In addition, enhanced collagen I (COL-I) secretion, alkaline phosphatase activity, and extracellular matrix mineralization levels were detected from the B-CS coating. According to RT-PCR results, notable up-regulation expressions of mineralized tissue-related genes, such as runt-related transcription factor 2 (Runx2), bone sialoprotein and osteocalcin, and bone morphogenetic protein 7 (BMP-7) were observed on the B-CS coating compared with the CS coating. The above results suggested that Ca 11 Si 4 B 2 O 22 coatings possess excellent osteogenic activity and might be a promising candidate for orthopedic applications.

  19. Electrochemical properties of N-doped hydrogenated amorphous carbon films fabricated by plasma-enhanced chemical vapor deposition methods

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Yoriko; Furuta, Masahiro; Kuriyama, Koichi; Kuwabara, Ryosuke; Katsuki, Yukiko [Division of Environmental Science and Engineering, Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan); Kondo, Takeshi [Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510 (Japan); Fujishima, Akira [Kanagawa Advanced Science and Technology (KAST), 3-2-1, Sakato, Takatsu-ku, Kawasaki-shi, Kanagawa 213-0012 (Japan); Honda, Kensuke, E-mail: khonda@yamaguchi-u.ac.j [Division of Environmental Science and Engineering, Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan)

    2011-01-01

    Nitrogen-doped hydrogenated amorphous carbon thin films (a-C:N:H, N-doped DLC) were synthesized with microwave-assisted plasma-enhanced chemical vapor deposition widely used for DLC coating such as the inner surface of PET bottles. The electrochemical properties of N-doped DLC surfaces that can be useful in the application as an electrochemical sensor were investigated. N-doped DLC was easily fabricated using the vapor of nitrogen contained hydrocarbon as carbon and nitrogen source. A N/C ratio of resulting N-doped DLC films was 0.08 and atomic ratio of sp{sup 3}/sp{sup 2}-bonded carbons was 25/75. The electrical resistivity and optical gap were 0.695 {Omega} cm and 0.38 eV, respectively. N-doped DLC thin film was found to be an ideal polarizable electrode material with physical stability and chemical inertness. The film has a wide working potential range over 3 V, low double-layer capacitance, and high resistance to electrochemically induced corrosion in strong acid media, which were the same level as those for boron-doped diamond (BDD). The charge transfer rates for the inorganic redox species, Fe{sup 2+/3+} and Fe(CN){sub 6}{sup 4-/3-} at N-doped DLC were sufficiently high. The redox reaction of Ce{sup 2+/3+} with standard potential higher than H{sub 2}O/O{sub 2} were observed due to the wider potential window. At N-doped DLC, the change of the kinetics of Fe(CN){sub 6}{sup 3-/4-} by surface oxidation is different from that at BDD. The rate of Fe(CN){sub 6}{sup 3-/4-} was not varied before and after oxidative treatment on N-doped DLC includes sp{sup 2} carbons, which indicates high durability of the electrochemical activity against surface oxidation.

  20. Spectroscopic ellipsometry characterization of nano-crystalline diamondfilms prepared at various substrate temperatures and pulsed plasma frequencies using microwave plasma enhanced chemical vapor deposition apparatus with linear antenna delivery

    Czech Academy of Sciences Publication Activity Database

    Mistrík, J.; Janíček, P.; Taylor, Andrew; Fendrych, František; Fekete, Ladislav; Jäger, Aleš; Nesládek, M.

    2014-01-01

    Roč. 571, č. 1 (2014), s. 230-237 ISSN 0040-6090 R&D Projects: GA ČR GA13-31783S; GA MŠk(CZ) LM2011026 Grant - others: COST Nano TP(XE) MP0901; OP VK(XE) CZ.1.07/2.3.00/20.0306 Institutional support: RVO:68378271 Keywords : nanocrystalline diamond * thin films * microwave plasma-enhanced chemical vapor deposition * pulsed plasma * low deposition temperature Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.759, year: 2014

  1. Improvement of the characteristics of chemical bath deposition-cadmium sulfide films deposited on an O{sub 2} plasma-treated polyethylene terephthalate substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Donggun [Department of Electronic Engineering, Korea National University of Transportation, Chungju-si, Chungcheongbuk-do 380-702 (Korea, Republic of); Lee, Jaehyeong [School of Electronic and Electrical Engineering, Sungkyunkwan University 300, Cheoncheon-dong, Jangan-gu, Sunwon, Kyeonggi-do, 440-746 (Korea, Republic of); Song, Woochang, E-mail: wcsong@kangwon.ac.kr [Department of Electrical Engineering, Kangwon National University, Samcheok-si, Gangwon-do 245-711 (Korea, Republic of)

    2013-11-01

    We prepared cadmium sulfide (CdS) films on a polyethylene terephthalate (PET) substrate by a chemical bath deposition (CBD) technique. To improve the adhesion between the CdS film and the PET substrate, the substrate was pre-treated with an O{sub 2} plasma by an inductively coupled plasma. The surface characterizations of the pre-treated PET substrate were analyzed by a contact angle measurement and atomic force microscopy. The results showed that that O{sub 2} plasma-treated PET films had more hydrophilic surface. The hydrophilic property of the substrate is one of the important factors when a film is prepared by CBD. The structural and the optical properties of the CdS films, deposited on PET substrates, were analyzed by using a scanning electron microscope, X-ray diffraction and a UV–visible spectrophotometer. The CdS films were formed on a compact and granular structure. The optical transmittance was also improved. Therefore, the O{sub 2} plasma treatment of a PET surface is an effective method of preparing CdS films deposited on substrates by CBD. - Highlights: • Chemical bath deposition of CdS film for flexible solar cells • O{sub 2} plasma treatment improved adhesion between the CdS and polymer substrate • Identification of best fabrication condition of CdS window layers for flexible solar cells.

  2. Controlled growth of carbon nanofibers using plasma enhanced chemical vapor deposition: Effect of catalyst thickness and gas ratio

    International Nuclear Information System (INIS)

    Saidin, M.A.R.; Ismail, A.F.; Sanip, S.M.; Goh, P.S.; Aziz, M.; Tanemura, M.

    2012-01-01

    The characteristics of carbon nanofibers (CNFs) grown, using direct current plasma enhanced chemical vapor deposition system reactor under various acetylene to ammonia gas ratios and different catalyst thicknesses were studied. Nickel/Chromium-glass (Ni/Cr-glass) thin film catalyst was employed for the growth of CNF. The grown CNFs were then characterized using Raman spectroscopy, field emission scanning electron microscopy and transmission electron microscopy (TEM). Raman spectroscopy showed that the Ni/Cr-glass with thickness of 15 nm and gas ratio acetylene to ammonia of 1:3 produced CNFs with the lowest I D /I G value (the relative intensity of D-band to G-band). This indicated that this catalyst thickness and gas ratio value is the optimum combination for the synthesis of CNFs under the conditions studied. TEM observation pointed out that the CNFs produced have 104 concentric walls and the residual catalyst particles were located inside the tubes of CNFs. It was also observed that structural morphology of the grown CNFs was influenced by acetylene to ammonia gas ratio and catalyst thickness.

  3. Controlled growth of carbon nanofibers using plasma enhanced chemical vapor deposition: Effect of catalyst thickness and gas ratio

    Energy Technology Data Exchange (ETDEWEB)

    Saidin, M.A.R. [Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru (Malaysia); Ismail, A.F., E-mail: afauzi@utm.my [Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru (Malaysia); Sanip, S.M.; Goh, P.S.; Aziz, M. [Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru (Malaysia); Tanemura, M. [Department of Frontier Material, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2012-01-31

    The characteristics of carbon nanofibers (CNFs) grown, using direct current plasma enhanced chemical vapor deposition system reactor under various acetylene to ammonia gas ratios and different catalyst thicknesses were studied. Nickel/Chromium-glass (Ni/Cr-glass) thin film catalyst was employed for the growth of CNF. The grown CNFs were then characterized using Raman spectroscopy, field emission scanning electron microscopy and transmission electron microscopy (TEM). Raman spectroscopy showed that the Ni/Cr-glass with thickness of 15 nm and gas ratio acetylene to ammonia of 1:3 produced CNFs with the lowest I{sub D}/I{sub G} value (the relative intensity of D-band to G-band). This indicated that this catalyst thickness and gas ratio value is the optimum combination for the synthesis of CNFs under the conditions studied. TEM observation pointed out that the CNFs produced have 104 concentric walls and the residual catalyst particles were located inside the tubes of CNFs. It was also observed that structural morphology of the grown CNFs was influenced by acetylene to ammonia gas ratio and catalyst thickness.

  4. Bacterial attachment on titanium surfaces is dependent on topography and chemical changes induced by nonthermal atmospheric pressure plasma.

    Science.gov (United States)

    Jeong, Won-Seok; Kwon, Jae-Sung; Lee, Jung-Hwan; Uhm, Soo-Hyuk; Ha Choi, Eun; Kim, Kwang-Mahn

    2017-07-26

    Here, we investigated the antibacterial effects of chemical changes induced by nonthermal atmospheric pressure plasma (NTAPP) on smooth and rough Ti. The morphologies of smooth and rough surfaces of Ti were examined using scanning electron microscopy (SEM). Both Ti specimens were then treated for 10 min by NTAPP with nitrogen gas. The surface roughness, chemistry, and wettability were examined by optical profilometry, x-ray photoelectron spectroscopy, and water contact angle analysis, respectively. Bacterial attachment was measured by determining the number of colony forming units and by SEM analysis. The rough Ti showed irregular micropits, whereas smooth Ti had a relatively regular pattern on the surface. There were no differences in morphology between samples before and after NTAPP treatment. NTAPP treatment resulted in changes from hydrophobic to hydrophilic properties on rough and smooth Ti; rough Ti showed relatively higher hydrophilicity. Before NTAPP treatment, Streptococcus sanguinis (S. sanguinis) showed greater attachment on rough Ti, and after NTAPP treatment, there was a significant reduction in bacterial attachment. Moreover, the bacterial attachment rate was significantly lower on rough Ti, and the structure of S. sanguinis colonies were significantly changed on NTAPP-treated Ti. NTAPP treatment inhibited bacterial attachment surrounding titanium implants, regardless of surface topography. Therefore, NTAPP treatment on Ti is a next-generation tool for antibacterial applications in the orthopaedic and dental fields.

  5. Effects of Pretreatment on the Electronic Properties of Plasma Enhanced Chemical Vapor Deposition Hetero-Epitaxial Graphene Devices

    Science.gov (United States)

    Zhang, Lian-Chang; Shi, Zhi-Wen; Yang, Rong; Huang, Jian

    2014-09-01

    Quasi-monolayer graphene is successfully grown by the plasma enhanced chemical vapor deposition heteroepitaxial method we reported previously. To measure its electrical properties, the prepared graphene is fabricated into Hall ball shaped devices by the routine micro-fabrication method. However, impurity molecules adsorbed onto the graphene surface will impose considerable doping effects on the one-atom-thick film material. Our experiment demonstrates that pretreatment of the device by heat radiation baking and electrical annealing can dramatically influence the doping state of the graphene and consequently modify the electrical properties. While graphene in the as-fabricated device is highly p-doped, as confirmed by the position of the Dirac point at far more than +60 V, baking treatment at temperatures around 180°C can significantly lower the doping level and reduce the conductivity. The following electrical annealing is much more efficient to desorb the extrinsic molecules, as confirmed by the in situ measurement, and as a result, further modify the doping state and electrical properties of the graphene, causing a considerable drop of the conductivity and a shifting of Dirac point from beyond +60 V to 0 V.

  6. Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Oliveira, M. H.; Viana, G. A.; de Lima, M. M.; Cros, A.; Cantarero, A.; Marques, F. C.

    2010-12-01

    Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH4) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

  7. Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Oliveira, M. H. Jr.; Viana, G. A.; Marques, F. C.; Lima, M. M. Jr. de; Cros, A.; Cantarero, A.

    2010-01-01

    Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH 4 ) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

  8. Coating of diamond-like carbon nanofilm on alumina by microwave plasma enhanced chemical vapor deposition process.

    Science.gov (United States)

    Rattanasatien, Chotiwan; Tonanon, Nattaporn; Bhanthumnavin, Worawan; Paosawatyanyong, Boonchoat

    2012-01-01

    Diamond-like carbon (DLC) nanofilms with thickness varied from under one hundred to a few hundred nanometers have been successfully deposited on alumina substrates by microwave plasma enhanced chemical vapor deposition (MW-PECVD) process. To obtain dense continuous DLC nanofilm coating over the entire sample surface, alumina substrates were pre-treated to enhance the nucleation density. Raman spectra of DLC films on samples showed distinct diamond peak at around 1332 cm(-1), and the broad band of amorphous carbon phase at around 1550 cm(-1). Full width at half maximum height (FWHM) values indicated good formation of diamond phase in all films. The result of nano-indentation test show that the hardness of alumina samples increase from 7.3 +/- 2.0 GPa in uncoated samples to 15.8 +/- 4.5-52.2 +/- 2.1 GPa in samples coated with DLC depending on the process conditions. It is observed that the hardness values are still in good range although the thickness of the films is less than a hundred nanometer.

  9. Comparative Study of Furnace and Flash Lamp Annealed Silicon Thin Films Grown by Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Maheshwar Shrestha

    2018-03-01

    Full Text Available Low-temperature growth of microcrystalline silicon (mc-Si is attractive for many optoelectronic device applications. This paper reports a detailed comparison of optical properties, microstructure, and morphology of amorphous silicon (a-Si thin films crystallized by furnace annealing and flash lamp annealing (FLA at temperatures below the softening point of glass substrate. The initial a-Si films were grown by plasma enhanced chemical vapor deposition (PECVD. Reflectance measurement indicated characteristic peak in the UV region ~280 nm for the furnace annealed (>550 °C and flash lamp annealed films, which provided evidence of crystallization. The film surface roughness increased with increasing the annealing temperature as well as after the flash lamp annealing. X-ray diffraction (XRD measurement indicated that the as-deposited samples were purely amorphous and after furnace crystallization, the crystallites tended to align in one single direction (202 with uniform size that increased with the annealing temperature. On the other hand, the flash lamp crystalized films had randomly oriented crystallites with different sizes. Raman spectroscopy showed the crystalline volume fraction of 23.5%, 47.3%, and 61.3% for the samples annealed at 550 °C, 650 °C, and with flash lamp, respectively. The flash lamp annealed film was better crystallized with rougher surface compared to furnace annealed ones.

  10. Excimer laser recrystallization of nanocrystalline-Si films deposited by inductively coupled plasma chemical vapour deposition at 150 deg. C

    International Nuclear Information System (INIS)

    Park, Joong-Hyun; Han, Sang-Myeon; Park, Sang-Geun; Han, Min-Koo; Shin, Moon-Young

    2006-01-01

    Polycrystalline silicon thin film transistors (poly-Si TFTs) fabricated at low temperature (under 200 deg. C) have been widely investigated for flexible substrate applications such as a transparent plastic substrate. Unlike the conventional TFT process using glass substrate, the maximum process temperature should be kept less than 200 deg. C in order to avoid thermal damage on flexible substrates. We report the characteristics of nanocrystalline silicon (nc-Si) irradiated by an excimer laser. Nc-Si precursors were deposited on various buffer layers by inductively coupled plasma chemical vapour deposition (ICP-CVD) at 150 deg. C. We employed various buffer layers, such as silicon nitride (SiN X ) and silicon dioxide (SiO 2 ), in order to report recrystallization characteristics in connection with a buffer layer of a different thermal conductivity. The dehydrogenation and recrystallization was performed by step-by-step excimer laser annealing (ELA) (XeCl,λ=308 nm) in order to prevent the explosive release of hydrogen atoms. The grain size of the poly-Si film, which was recrystallized on the various buffer layers, was measured by scanning electron microscopy (SEM) at each laser energy density. The process margin of step-by-step ELA employing the SiN X buffer layer is wider than SiO 2 and the maximum grain size slightly increased

  11. Enhanced field emission characteristics of boron doped diamond films grown by microwave plasma assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Koinkar, Pankaj M. [Center for International Cooperation in Engineering Education (CICEE), University of Tokushima, 2-1 Minami-josanjima-cho, Tokushima 770-8506 (Japan); Patil, Sandip S. [Center for Advanced Studies in Materials Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Kim, Tae-Gyu [Department of Nano System and Process Engineering, Pusan National University, 50 Cheonghak-ri, Samrangjin-eup, Miryang, Gyeongnam, Pusan 627-706 (Korea, Republic of); Yonekura, Daisuke [Department of Mechanical Engineering, University of Tokushima, 2-1 Minami-josanjima-cho, Tokushima 770-8506 (Japan); More, Mahendra A., E-mail: mam@physics.unipune.ac.in [Center for Advanced Studies in Materials Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Joag, Dilip S. [Center for Advanced Studies in Materials Science and Condensed Matter Physics, Department of Physics, University of Pune, Pune 411007 (India); Murakami, Ri-ichi, E-mail: murakami@me.tokushima-u.ac.jp [Department of Mechanical Engineering, University of Tokushima, 2-1 Minami-josanjima-cho, Tokushima 770-8506 (Japan)

    2011-01-01

    Boron doped diamond films were synthesized on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) technique. The effect of B{sub 2}O{sub 3} concentration varied from 1000 to 5000 ppm on the field emission characteristics was examined. The surface morphology and quality of films were characterized by scanning electron microscope (SEM) and Raman spectroscopy. The surface morphology obtained by SEM showed variation from facetted microcrystal covered with nanometric grains to cauliflower of nanocrystalline diamond (NCD) particles with increasing B{sub 2}O{sub 3} concentration. The Raman spectra confirm the formation of NCD films. The field emission properties of NCD films were observed to improve upon increasing boron concentration. The values of the onset field and threshold field are observed to be as low as 0.36 and 0.08 V/{mu}m, respectively. The field emission current stability investigated at the preset value of {approx}1 {mu}A is observed to be good, in each case. The enhanced field emission properties are attributed to the better electrical conductivity coupled with the nanometric features of the diamond films.

  12. Raman enhancement on ultra-clean graphene quantum dots produced by quasi-equilibrium plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Liu, Donghua; Chen, Xiaosong; Hu, Yibin; Sun, Tai; Song, Zhibo; Zheng, Yujie; Cao, Yongbin; Cai, Zhi; Cao, Min; Peng, Lan; Huang, Yuli; Du, Lei; Yang, Wuli; Chen, Gang; Wei, Dapeng; Wee, Andrew Thye Shen; Wei, Dacheng

    2018-01-15

    Graphene is regarded as a potential surface-enhanced Raman spectroscopy (SERS) substrate. However, the application of graphene quantum dots (GQDs) has had limited success due to material quality. Here, we develop a quasi-equilibrium plasma-enhanced chemical vapor deposition method to produce high-quality ultra-clean GQDs with sizes down to 2 nm directly on SiO 2 /Si, which are used as SERS substrates. The enhancement factor, which depends on the GQD size, is higher than conventional graphene sheets with sensitivity down to 1 × 10 -9  mol L -1 rhodamine. This is attributed to the high-quality GQDs with atomically clean surfaces and large number of edges, as well as the enhanced charge transfer between molecules and GQDs with appropriate diameters due to the existence of Van Hove singularities in the electronic density of states. This work demonstrates a sensitive SERS substrate, and is valuable for applications of GQDs in graphene-based photonics and optoelectronics.

  13. Multiscale multiphysics nonempirical approach to calculation of light emission properties of chemically active nonequilibrium plasma: application to Ar-GaI3 system

    International Nuclear Information System (INIS)

    Adamson, S; Astapenko, V; Chernysheva, I; Chorkov, V; Deminsky, M; Demchenko, G; Demura, A; Demyanov, A; Dyatko, N; Eletzkii, A; Knizhnik, A; Kochetov, I; Napartovich, A; Rykova, E; Sukhanov, L; Umanskii, S; Vetchinkin, A; Zaitsevskii, A; Potapkin, B

    2007-01-01

    Present-day computational techniques provide a possibility of evaluating properties of macrosystems using ab initio quantum chemistry and theories of elementary processes. Physical and chemical phenomena on very different timescales have to be taken into account (excitation, emission, chemical reactions, diffusion) at different levels of refining. This refining covers a very wide region of parameters starting from the structure of species up to the macro chemical mechanism of their conversion. This multilevel approach is described in detail in the paper and includes interaction and data transfer between different levels of phenomena description. In the framework of the approach, unknown properties of molecules, ions and atoms (structure, potential energy curves, transition dipole moments) are calculated based on quantum-chemical methods. The calculation results are used to evaluate rate characteristics of physical and chemical processes. The developed kinetic state-to-state scheme is then used to calculate the macro properties of the system under investigation. As an example of the multilevel approach, the emission properties of the Ar-GaI 3 positive column discharge plasma were calculated using the Chemical Work Bench computational environment. The calculations yield the electron energy balance and emission efficiency as functions of plasma parameters

  14. Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

    International Nuclear Information System (INIS)

    Cossement, Damien; Renaux, Fabian; Thiry, Damien; Ligot, Sylvie; Francq, Rémy; Snyders, Rony

    2015-01-01

    Graphical abstract: - Highlights: • Plasma polymer films have a chemical selectivity and a cross-linking degree which are known to vary in opposite trends. • Three plasma polymers families were used as model organic layers for cross-linking evaluation by ToF-SIMS and principal component analysis. • The data were cross-checked with related functional properties that are known to depend on the cross-linking degree (stability in solvent, mechanical properties, …). • The suggested cross-linking evaluation method was validated for different families of plasma polymers demonstrating that it can be seen as a “general” method. - Abstract: It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH_2-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (P_R_F), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high P_R_F. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with P_R_F excepted for the SH-PPF. These results have been cross

  15. Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cossement, Damien, E-mail: damien.cossement@materianova.be [Materia Nova Research Center, Parc Initialis, 1, Avenue Nicolas Copernic, B-7000 Mons (Belgium); Renaux, Fabian [Materia Nova Research Center, Parc Initialis, 1, Avenue Nicolas Copernic, B-7000 Mons (Belgium); Thiry, Damien; Ligot, Sylvie [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Francq, Rémy; Snyders, Rony [Materia Nova Research Center, Parc Initialis, 1, Avenue Nicolas Copernic, B-7000 Mons (Belgium); Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium)

    2015-11-15

    Graphical abstract: - Highlights: • Plasma polymer films have a chemical selectivity and a cross-linking degree which are known to vary in opposite trends. • Three plasma polymers families were used as model organic layers for cross-linking evaluation by ToF-SIMS and principal component analysis. • The data were cross-checked with related functional properties that are known to depend on the cross-linking degree (stability in solvent, mechanical properties, …). • The suggested cross-linking evaluation method was validated for different families of plasma polymers demonstrating that it can be seen as a “general” method. - Abstract: It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH{sub 2}-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (P{sub RF}), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high P{sub RF}. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with P{sub RF} excepted for the SH-PPF. These results have

  16. Characterization of Carbon-Contaminated B4C-Coated Optics after Chemically Selective Cleaning with Low-Pressure RF Plasma.

    Science.gov (United States)

    Moreno Fernández, H; Rogler, D; Sauthier, G; Thomasset, M; Dietsch, R; Carlino, V; Pellegrin, E

    2018-01-22

    Boron carbide (B 4 C) is one of the few materials that is expected to be most resilient with respect to the extremely high brilliance of the photon beam generated by free electron lasers (FELs) and is thus of considerable interest for optical applications in this field. However, as in the case of many other optics operated at light source facilities, B 4 C-coated optics are subject to ubiquitous carbon contaminations. Carbon contaminations represent a serious issue for the operation of FEL beamlines due to severe reduction of photon flux, beam coherence, creation of destructive interference, and scattering losses. A variety of B 4 C cleaning technologies were developed at different laboratories with varying success. We present a study regarding the low-pressure RF plasma cleaning of carbon contaminated B 4 C test samples via inductively coupled O 2 /Ar, H 2 /Ar, and pure O 2 RF plasma produced following previous studies using the same ibss GV10x downstream plasma source. Results regarding the chemistry, morphology as well as other aspects of the B 4 C optical coating before and after the plasma cleaning are reported. We conclude that among the above plasma processes only plasma based on pure O 2 feedstock gas exhibits the required chemical selectivity for maintaining the integrity of the B 4 C optical coatings.

  17. A study of the performance and properties of diamond like carbon (DLC) coatings deposited by plasma chemical vapor deposition (CVD) for two stroke engine components

    Energy Technology Data Exchange (ETDEWEB)

    Tither, D. [BEP Grinding Ltd., Manchester (United Kingdom); Ahmed, W.; Sarwar, M.; Penlington, R. [Univ. of Northumbria, Newcastle-upon-Tyne (United Kingdom)

    1995-12-31

    Chemical vapor deposition (CVD) using microwave and RF plasma is arguably the most successful technique for depositing diamond and diamond like carbon (DLC) films for various engineering applications. However, the difficulties of depositing diamond are nearly as extreme as it`s unique combination of physical, chemical and electrical properties. In this paper, the modified low temperature plasma enhanced CVD system is described. The main focus of this paper will be work related to deposition of DLC on metal matrix composite materials (MMCs) for application in two-stroke engine components and results will be presented from SEM, mechanical testing and composition analysis studies. The authors have demonstrated the feasibility of depositing DLC on MMCs for the first time using a vacuum deposition process.

  18. Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

    Science.gov (United States)

    Cossement, Damien; Renaux, Fabian; Thiry, Damien; Ligot, Sylvie; Francq, Rémy; Snyders, Rony

    2015-11-01

    It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH2-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (PRF), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high PRF. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with PRF excepted for the SH-PPF. These results have been cross-checked by the evaluation of functional properties of the plasma polymers namely a linear correlation with the stability of NH2-PPF in ethanol and a correlation with the mechanical properties of the COOR-PPF. For the SH-PPF family, the peculiar evolution of χ is supported by the understanding of the growth mechanism of the PPF from plasma diagnostic. The whole set of data clearly demonstrates the potential of the PCA method for extracting information on the microstructure of plasma polymers from ToF-SIMS measurements.

  19. Physics in Brazil in the next decade: atomic, molecular and optical physics, biological, chemical and medical physics, physics teaching and plasma physics

    International Nuclear Information System (INIS)

    1990-01-01

    This is an overview of physics in Brazil in the next decade. It is specially concerned with atomic, molecular and optical physics, biological chemical and medical physics, and also teaching of physics and plasma physics. It presents the main research groups in Brazil in the above mentioned areas. It talks as well, about financing new projects and the costs involved to improve these areas. (A.C.A.S.)

  20. Spectroscopic properties of nitrogen doped hydrogenated amorphous carbon films grown by radio frequency plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Hayashi, Y.; Yu, G.; Rahman, M. M.; Krishna, K. M.; Soga, T.; Jimbo, T.; Umeno, M.

    2001-01-01

    Nitrogen doped hydrogenated amorphous carbon thin films have been deposited by rf plasma-enhanced chemical vapor deposition using CH 4 as the source of carbon and with different nitrogen flow rates (N 2 /CH 4 gas ratios between 0 and 3), at 300 K. The dependence modifications of the optical and the structural properties on nitrogen incorporation were investigated using different spectroscopic techniques, such as, Raman spectroscopy, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, electron spin resonance (ESR), photoluminescence (PL) and spectroscopic ellipsometry (SE). Raman spectroscopy and IR absorption reveal an increase in sp 2 -bonded carbon or a change in sp 2 domain size with increasing nitrogen flow rate. It is found that the configuration of nitrogen atoms incorporated into an amorphous carbon network gradually changes from nitrogen atoms surrounded by three (σ bonded) to two (π bonded) neighboring carbons with increasing nitrogen flow rate. Tauc optical gap is reduced from 2.6 to 2.0 eV, and the ESR spin density and the peak-to-peak linewidth increase sharply with increasing nitrogen flow rate. Excellent agreement has been found between the measured SE data and modeled spectra, in which an empirical dielectric function of amorphous materials and a linear void distribution along the thickness have been assumed. The influence of nitrogen on the electronic density of states is explained based on the optical properties measured by UV-VIS and PL including nitrogen lone pair band. [copyright] 2001 American Institute of Physics

  1. One-Step Reforming of CO2 and CH4 into High-Value Liquid Chemicals and Fuels at Room Temperature by Plasma-Driven Catalysis.

    Science.gov (United States)

    Wang, Li; Yi, Yanhui; Wu, Chunfei; Guo, Hongchen; Tu, Xin

    2017-10-23

    The conversion of CO 2 with CH 4 into liquid fuels and chemicals in a single-step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one-step process from CO 2 and CH 4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50-60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH 4 and CO 2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  2. Effect of confining wall potential on charged collimated dust beam in low-pressure plasma

    International Nuclear Information System (INIS)

    Kausik, S. S.; Kakati, B.; Saikia, B. K.

    2013-01-01

    The effect of confining wall potential on charged collimated dust beam in low-pressure plasma has been studied in a dusty plasma experimental setup by applying electrostatic field to each channel of a multicusp magnetic cage. Argon plasma is produced by hot cathode discharge method at a pressure of 5×10 −4 millibars and is confined by a full line cusped magnetic field confinement system. Silver dust grains are produced by gas-evaporation technique and move upward in the form of a collimated dust beam due to differential pressure maintained between the dust and plasma chambers. The charged grains in the beam after coming out from the plasma column enter into the diagnostic chamber and are deflected by a dc field applied across a pair of deflector plates at different confining potentials. Both from the amount of deflection and the floating potential, the number of charges collected by the dust grains is calculated. Furthermore, the collimated dust beam strikes the Faraday cup, which is placed above the deflector plates, and the current (∼pA) so produced is measured by an electrometer at different confining potentials. The experimental results demonstrate the significant effect of confining wall potential on charging of dust grains

  3. Effect of confining wall potential on charged collimated dust beam in low-pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kausik, S. S.; Kakati, B.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402 (India)

    2013-05-15

    The effect of confining wall potential on charged collimated dust beam in low-pressure plasma has been studied in a dusty plasma experimental setup by applying electrostatic field to each channel of a multicusp magnetic cage. Argon plasma is produced by hot cathode discharge method at a pressure of 5×10{sup −4} millibars and is confined by a full line cusped magnetic field confinement system. Silver dust grains are produced by gas-evaporation technique and move upward in the form of a collimated dust beam due to differential pressure maintained between the dust and plasma chambers. The charged grains in the beam after coming out from the plasma column enter into the diagnostic chamber and are deflected by a dc field applied across a pair of deflector plates at different confining potentials. Both from the amount of deflection and the floating potential, the number of charges collected by the dust grains is calculated. Furthermore, the collimated dust beam strikes the Faraday cup, which is placed above the deflector plates, and the current (∼pA) so produced is measured by an electrometer at different confining potentials. The experimental results demonstrate the significant effect of confining wall potential on charging of dust grains.

  4. Effect of confining wall potential on charged collimated dust beam in low-pressure plasma

    Science.gov (United States)

    Kausik, S. S.; Kakati, B.; Saikia, B. K.

    2013-05-01

    The effect of confining wall potential on charged collimated dust beam in low-pressure plasma has been studied in a dusty plasma experimental setup by applying electrostatic field to each channel of a multicusp magnetic cage. Argon plasma is produced by hot cathode discharge method at a pressure of 5×10-4 millibars and is confined by a full line cusped magnetic field confinement system. Silver dust grains are produced by gas-evaporation technique and move upward in the form of a collimated dust beam due to differential pressure maintained between the dust and plasma chambers. The charged grains in the beam after coming out from the plasma column enter into the diagnostic chamber and are deflected by a dc field applied across a pair of deflector plates at different confining potentials. Both from the amount of deflection and the floating potential, the number of charges collected by the dust grains is calculated. Furthermore, the collimated dust beam strikes the Faraday cup, which is placed above the deflector plates, and the current (˜pA) so produced is measured by an electrometer at different confining potentials. The experimental results demonstrate the significant effect of confining wall potential on charging of dust grains.

  5. Process control by optical emission spectroscopy during growth of a-C:H from a CH4 plasma by plasma-enhanced chemical vapour deposition

    DEFF Research Database (Denmark)

    Barholm-Hansen, C; Bentzon, MD; Vigild, Martin Etchells

    1994-01-01

    During the growth of a-C:H thin films for tribological applications, the characteristic optical emission from a CH4 plasma was used to estimate growth conditions such as the degree of dissociation of the feed gas, the deposition rate and the presence of impurities. Films were fabricated with vari...

  6. Towards ideal NOx control technology for bio-oils and a gas multi-fuel boiler system using a plasma-chemical hybrid process

    International Nuclear Information System (INIS)

    Fujishima, Hidekatsu; Takekoshi, Kenichi; Kuroki, Tomoyuki; Tanaka, Atsushi; Otsuka, Keiichi; Okubo, Masaaki

    2013-01-01

    Highlights: • A multi-fuel boiler system combined with NO x aftertreatment is developed. • NO x is removed from flue gas by a plasma-chemical hybrid process. • Waste bio-oils are utilized as renewable energy source and for CO 2 reduction. • Ultra low NO x emission less than 2 ppm is achieved. • The boiler system is applicable for industrial use. - Abstract: A super-clean boiler system comprising a multi-fuel boiler and a reactor for plasma-chemical hybrid NO x aftertreatment is developed, and its industrial applications are examined. The purpose of this research is to optimally reduce NO x emission and utilize waste bio-oil as a renewable energy source. First, NO oxidation using indirect plasma at elevated flue gas temperatures is investigated. It is clarified that more than 98% of NO is oxidized when the temperature of the flue gas is less than 130 °C. Three types of waste bio-oils (waste vegetable oil, rice bran oil, and fish oil) are burned in the boiler as fuels with a rotary-type burner for CO 2 reduction considering carbon neutrality. NO x in the flue gases of these bio-oils is effectively reduced by the indirect plasma-chemical hybrid treatment. Ultralow NO x emission less than 2 ppm is achieved for 450 min in the firing of city natural gas fuel. The boiler system can be successfully operated automatically according to unsteady steam demand and using an empirical equation for Na 2 SO 3 supply rate, and can be used in industries as an ideal NO x control technology

  7. Development of a gas-cylinder-free plasma desorption/ionization system for on-site detection of chemical warfare agents.

    Science.gov (United States)

    Iwai, Takahiro; Kakegawa, Ken; Aida, Mari; Nagashima, Hisayuki; Nagoya, Tomoki; Kanamori-Kataoka, Mieko; Miyahara, Hidekazu; Seto, Yasuo; Okino, Akitoshi

    2015-06-02

    A gas-cylinder-free plasma desorption/ionization system was developed to realize a mobile on-site analytical device for detection of chemical warfare agents (CWAs). In this system, the plasma source was directly connected to the inlet of a mass spectrometer. The plasma can be generated with ambient air, which is drawn into the discharge region by negative pressure in the mass spectrometer. High-power density pulsed plasma of 100 kW could be generated by using a microhollow cathode and a laboratory-built high-intensity pulsed power supply (pulse width: 10-20 μs; repetition frequency: 50 Hz). CWAs were desorbed and protonated in the enclosed space adjacent to the plasma source. Protonated sample molecules were introduced to the mass spectrometer by airflow through the discharge region. To evaluate the analytical performance of this device, helium and air plasma were directly irradiated to CWAs in the gas-cylinder-free plasma desorption/ionization system and the protonated molecules were analyzed by using an ion-trap mass spectrometer. A blister agent (nitrogen mustard 3) and nerve gases [cyclohexylsarin (GF), tabun (GA), and O-ethyl S-2-N,N-diisopropylaminoethyl methylphosphonothiolate (VX)] in solution in n-hexane were applied to the Teflon rod and used as test samples, after solvent evaporation. As a result, protonated molecules of CWAs were successfully observed as the characteristic ion peaks at m/z 204, 181, 163, and 268, respectively. In air plasma, the limits of detection were estimated to be 22, 20, 4.8, and 1.0 pmol, respectively, which were lower than those obtained with helium plasma. To achieve quantitative analysis, calibration curves were made by using CWA stimulant dipinacolyl methylphosphonate as an internal standard; straight correlation lines (R(2) = 0.9998) of the peak intensity ratios (target per internal standard) were obtained. Remarkably, GA and GF gave protonated dimer ions, and the ratios of the protonated dimer ions to the protonated

  8. Physics of the Advanced Plasma Source: a review of recent experimental and modeling approaches

    International Nuclear Information System (INIS)

    Brinkmann, R P; Schröder, B; Lapke, M; Storch, R; Styrnoll, T; Awakowicz, P; Harhausen, J; Foest, R; Hannemann, M; Loffhagen, D; Ohl, A

    2016-01-01

    The Advanced Plasma Source (APS), a gridless hot cathode glow discharge capable of generating an ion beam with an energy of up to 150 eV and a flux of 10 19 s −1 , is a standard industrial tool for the process of plasma ion-assisted deposition (PIAD). This manuscript details the results of recent experimental and modeling work aimed at a physical understanding of the APS. A three-zone model is proposed which consists of (i) the ionization zone (the source itself) where the plasma is very dense, hot, and has a high ionization rate, (ii) the acceleration zone (of  ∼20 cm extension) where a strong outward-directed electric field accelerates the primary ions to a high kinetic energy, and (iii) a drift zone (the rest of the process chamber) where the emerging plasma beam is further modified by resonant charge exchange collisions that neutralize some of the energetic ions and generate, at the same time, a flux of slow ions. (paper)

  9. Relationships between organohalogen contaminants and blood plasma clinical-chemical parameters in chicks of three raptor species from Northern Norway

    DEFF Research Database (Denmark)

    Sonne, Christian; Bustnes, Jan Ove; Herzke, Dorte

    2010-01-01

    :creatinine were significantly positively correlated to various OHCs (all: praptor chicks of Northern Scandinavia may impact blood plasma biochemistry in a way that indicates impacts on liver, kidney, bone...

  10. Chemical analysis of reactive species and antimicrobial activity of/nwater treated by nanosecond pulsed DBD air plasma

    Czech Academy of Sciences Publication Activity Database

    Laurita, R.; Barbieri, D.; Gherardi, M.; Colombo, V.; Lukeš, Petr

    2015-01-01

    Roč. 3, č. 2 (2015), s. 53-61 ISSN 2212-8166 R&D Projects: GA MŠk(CZ) LD14080 Grant - others:European Cooperation in Science and Technology(XE) COST TD1208 Institutional support: RVO:61389021 Keywords : Dielectric barrier discharge * Plasma activated water * Reactive species * Peroxynitrite * Phenol degradation * Candida albicans * Staphylococcus aureus * Antimicrobial activity * Nosocomial infections Subject RIV: BL - Plasma and Gas Discharge Physics http://www.sciencedirect.com/science/article/pii/S2212816615300081

  11. Oral Administration of the Japanese Traditional Medicine Keishibukuryogan-ka-yokuinin Decreases Reactive Oxygen Metabolites in Rat Plasma: Identification of Chemical Constituents Contributing to Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Yosuke Matsubara

    2017-02-01

    Full Text Available Insufficient detoxification and/or overproduction of reactive oxygen species (ROS induce cellular and tissue damage, and generated reactive oxygen metabolites become exacerbating factors of dermatitis. Keishibukuryogan-ka-yokuinin (KBGY is a traditional Japanese medicine prescribed to treat dermatitis such as acne vulgaris. Our aim was to verify the antioxidant properties of KBGY, and identify its active constituents by blood pharmacokinetic techniques. Chemical constituents were quantified in extracts of KBGY, crude components, and the plasma of rats treated with a single oral administration of KBGY. Twenty-three KBGY compounds were detected in plasma, including gallic acid, prunasin, paeoniflorin, and azelaic acid, which have been reported to be effective for inflammation. KBGY decreased level of the diacron-reactive oxygen metabolites (d-ROMs in plasma. ROS-scavenging and lipid hydroperoxide (LPO generation assays revealed that gallic acid, 3-O-methylgallic acid, (+-catechin, and lariciresinol possess strong antioxidant activities. Gallic acid was active at a similar concentration to the maximum plasma concentration, therefore, our findings indicate that gallic acid is an important active constituent contributing to the antioxidant effects of KBGY. KBGY and its active constituents may improve redox imbalances induced by oxidative stress as an optional treatment for skin diseases.

  12. Simultaneous determination of clebopride and a major metabolite N-desbenzylclebopride in plasma by capillary gas chromatography-negative-ion chemical ionization mass spectrometry.

    Science.gov (United States)

    Robinson, P R; Jones, M D; Maddock, J; Rees, L W

    1991-03-08

    A procedure for the simultaneous assay of clebopride and its major metabolite N-desbenzylclebopride in plasma has been developed. The method utilizes capillary gas chromatography-negative-ion chemical ionization mass spectrometry with selected-ion monitoring of characteristic ions. Employing 2-ethoxy analogues as internal standards, the benzamides were extracted from basified plasma using dichloromethane. Subsequent reaction with heptafluorobutyric anhydride produced volatile mono- and diheptafluorobutyryl derivatives of clebopride and N-desbenzylclebopride, respectively. The methane negative-ion mass spectra of these derivatives exhibited intense high-mass ions ideal for specific quantitation of low levels in biological fluids. Using this procedure the recovery of the drug and metabolite from human plasma was found to be 84.4 +/- 1.5% (n = 3) and 77.4 +/- 4.7% (n = 3), respectively, at 0.5 ng/ml. Measurement of both compounds down to 0.10 ng/ml with a coefficient of variation of less than 10.5% is described. Plasma levels are reported in four volunteers up to 24 h following oral administration of 1 mg of clebopride malate salt.

  13. Plasma Nitriding of AISI 304 Stainless Steel in Cathodic and Floating Electric Potential: Influence on Morphology, Chemical Characteristics and Tribological Behavior

    Science.gov (United States)

    Li, Yang; He, Yongyong; Wang, Wei; Mao, Junyuan; Zhang, Lei; Zhu, Yijie; Ye, Qianwen

    2018-03-01

    In direct current plasma nitriding (DCPN), the treated components are subjected to a high cathodic potential, which brings several inherent shortcomings, e.g., damage by arcing and the edging effect. In active screen plasma nitriding (ASPN) processes, the cathodic potential is applied to a metal screen that surrounds the workload, and the component to be treated is placed in a floating potential. Such an electrical configuration allows plasma to be formed on the metal screen surface rather than on the component surface; thus, the shortcomings of the DCPN are eliminated. In this work, the nitrided experiments were performed using a plasma nitriding unit. Two groups of samples were placed on the table in the cathodic and the floating potential, corresponding to the DCPN and ASPN, respectively. The floating samples and table were surrounded by a steel screen. The DCPN and ASPN of the AISI 304 stainless steels are investigated as a function of the electric potential. The samples were characterized using scanning electron microscopy with energy-dispersive x-ray spectroscopy, x-ray diffraction, atomic force microscopy and transmission electron microscope. Dry sliding ball-on-disk wear tests were conducted on the untreated substrate, DCPN and ASPN samples. The results reveal that all nitrided samples successfully produced similar nitrogen-supersaturated S phase layers on their surfaces. This finding also shows the strong impact of the electric potential of the nitriding process on the morphology, chemical characteristics, hardness and tribological behavior of the DCPN and ASPN samples.

  14. Properties and electric characterizations of tetraethyl orthosilicate-based plasma enhanced chemical vapor deposition oxide film deposited at 400 °C for through silicon via application

    International Nuclear Information System (INIS)

    Su, Meiying; Yu, Daquan; Liu, Yijun; Wan, Lixi; Song, Chongshen; Dai, Fengwei; Xue, Kai; Jing, Xiangmeng; Guidotti, Daniel

    2014-01-01

    The dielectric via liner of through silicon vias was deposited at 400 °C using a tetraethyl orthosilicate (TEOS)-based plasma enhanced chemical vapor deposition process in a via-middle integration scheme. The morphology, conformality and chemical compositions of the liner film were characterized using field emission scanning electron microscopy and Fourier Transform Infrared spectroscopy. The thermal properties and electrical performance of blanket TEOS films were investigated by high temperature film stress and mercury probe Capacitance–Voltage measurements. The TEOS SiO 2 films show good conformality, excellent densification, low thermal stress, high breakdown voltage and low current leakage. - Highlights: • Tetraethyl orthosilicate-based oxide films were deposited for packaging application. • The oxide films deposited plasma-enhanced chemical vapor deposition (PECVD) at 400 °C. • The PECVD oxide films exhibit good step coverage. • The 400 °C PECVD oxide films exhibit low thermal stress and current leakage. • The 400 °C PECVD oxide films show high breakdown voltage and acceptable permittivity

  15. Chemical compatibility and properties of suspension plasma-sprayed SrTiO3-based anodes for intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu

    2014-10-01

    La-doped strontium titanate (LST) is a promising, redox-stable perovskite material for direct hydrocarbon oxidation anodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, nano-sized LST and Sm-doped ceria (SDC) powders are produced by the sol-gel and glycine-nitrate processes, respectively. The chemical compatibility between LST and electrolyte materials is studied. A LST-SDC composite anode is prepared by suspension plasma spraying (SPS). The effects of annealing conditions on the phase structure, microstructure, and chemical stability of the LST-SDC composite anode are investigated. The results indicate that the suspension plasma-sprayed LST-SDC anode has the same phase structure as the original powders. LST exhibits a good chemical compatibility with SDC and Mg/Sr-doped lanthanum gallate (LSGM). The anode has a porosity of ∼40% with a finely porous structure that provides high gas permeability and a long three-phase boundary for the anode reaction. Single cells assembled with the LST-SDC anode, La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte, and La0.8Sr0.2CoO3-SDC cathode show a good performance at 650-800 °C. The annealing reduces the impedances due to the enhancement in the bonding between the particles in the anode and interface of anode and LSGM electrolyte, thus improving the output performance of the cell.

  16. Properties and electric characterizations of tetraethyl orthosilicate-based plasma enhanced chemical vapor deposition oxide film deposited at 400 °C for through silicon via application

    Energy Technology Data Exchange (ETDEWEB)

    Su, Meiying, E-mail: sumeiying@ime.ac.cn [Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029 (China); National Center for Advanced Packaging, Wuxi 214135 (China); Yu, Daquan, E-mail: yudaquan@ime.ac.cn [Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029 (China); National Center for Advanced Packaging, Wuxi 214135 (China); Jiangsu R and D Center for Internet of Things, Wuxi 214135 (China); Liu, Yijun [Piotech Co. Ltd, Shenyang 110179 (China); Wan, Lixi [Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029 (China); Song, Chongshen; Dai, Fengwei [Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029 (China); National Center for Advanced Packaging, Wuxi 214135 (China); Xue, Kai [National Center for Advanced Packaging, Wuxi 214135 (China); Jing, Xiangmeng [Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029 (China); National Center for Advanced Packaging, Wuxi 214135 (China); Guidotti, Daniel [Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029 (China)

    2014-01-01

    The dielectric via liner of through silicon vias was deposited at 400 °C using a tetraethyl orthosilicate (TEOS)-based plasma enhanced chemical vapor deposition process in a via-middle integration scheme. The morphology, conformality and chemical compositions of the liner film were characterized using field emission scanning electron microscopy and Fourier Transform Infrared spectroscopy. The thermal properties and electrical performance of blanket TEOS films were investigated by high temperature film stress and mercury probe Capacitance–Voltage measurements. The TEOS SiO{sub 2} films show good conformality, excellent densification, low thermal stress, high breakdown voltage and low current leakage. - Highlights: • Tetraethyl orthosilicate-based oxide films were deposited for packaging application. • The oxide films deposited plasma-enhanced chemical vapor deposition (PECVD) at 400 °C. • The PECVD oxide films exhibit good step coverage. • The 400 °C PECVD oxide films exhibit low thermal stress and current leakage. • The 400 °C PECVD oxide films show high breakdown voltage and acceptable permittivity.

  17. Composition and partition functions of partially ionized hydrogen plasma in Non-Local Thermal Equilibrium (Non-LThE) and Non-Local Chemical Equilibrium (Non-LChE)

    International Nuclear Information System (INIS)

    Chen Kuan; Eddy, T.L.

    1993-01-01

    A GTME (Generalized MultiThermodynamic Equilibrium) plasma model is developed for plasmas in both Non-LThE (Non-Local Thermal Equilibrium) and Non-LChE (Non-Local Chemical Equilibrium). The model uses multitemperatures for thermal nonequilibrium and non-zero chemical affinities as a measure of the deviation from chemical equilibrium. The plasma is treated as an ideal gas with the Debye-Hueckel approximation employed for pressure correction. The proration method is used when the cutoff energy level is between two discrete levels. The composition and internal partition functions of a hydrogen plasma are presented for electron temperatures ranging from 5000 to 35000 K and pressures from 0.1 to 1000 kPa. Number densities of 7 different species of hydrogen plasma and internal partition functions of different energy modes (rotational, vibrational, and electronic excitation) are computed for three affinity values. The results differ from other plasma properties in that they 1) are not based on equilibrium properties; and 2) are expressed as a function of different energy distribution parameters (temperatures) within each energy mode of each species as appropriate. The computed number densities and partition functions are applicable to calculating the thermodynamic, transport, and radiation properties of a hydrogen plasma not in thermal and chemical equilibria. The nonequilibrium plasma model and plasma compositions presented in this paper are very useful to the diagnosis of high-speed and/or low-pressure plasma flows in which the assumptions of local thermal and chemical equilibrium are invalid. (orig.)

  18. The innovative plasma tilting furnace for treatment of radioactive and problematic chemical waste. From paper to reality

    International Nuclear Information System (INIS)

    Deckers, Jan; Gonzalez, Alicia; Cano, David

    2014-01-01

    The operation and maintenance of nuclear power plants, the nuclear fuel cycle in general, research laboratories and pharmaceutical, medical and industrial facilities generate large amounts of low-level radioactive wastes which, along with the historical radioactive wastes from past nuclear activities, needs to be treated to minimise the volume to be disposed of. Plasma technology offers a very effective way of treating this waste with a high volume reduction factor (VRF), free from organics, liquids and moisture, and meets without doubt the acceptance criteria for safe storage and disposal. By means of a plasma beam of approximately 5000 deg. C, the inorganic materials are melted into a glassy slag, containing the radioactive isotopes while the organic material is gasified and afterwards oxidized in an afterburner and purified in an off-gas cleaning system. This paper describes the principles of plasma, the different waste feed systems, off gas treatment, operational experience and future plasma plants. In particular a new full-scale plasma facility for the treatment of radioactive waste at the Kozloduy Nuclear Power Plant in Bulgaria is described. This facility is designed and now under construction by the Joint Venture Iberdrola Ingenieria y Construccion and Belgoprocess. (authors)

  19. The influence of incorporating MgO into Ni-based cermets by plasma spraying on anode microstructural and chemical stability in dry methane

    Science.gov (United States)

    Lay, E.; Metcalfe, C.; Kesler, O.

    2012-11-01

    The Solution Precursor Plasma Spray (SPPS) process was successfully used to deposit cermet coatings that exhibit fine microstructures with high surface area. MgO addition in Ni-YSZ and Ni-SDC cermets results in (Ni,Mg)O solid solution formation, and nickel particles after reduction are finer than in coatings without magnesia. The influence of MgO on the chemical stability of cermets in anodic operating conditions is discussed. It was found that a sufficient amount of magnesia addition (Ni0.9(MgO)0.1) helps to reduce carbon deposition in dry methane.

  20. Physico-chemical study of coating plasma duplex alumina/hydroxyapatite for medical applications relation elaboration/structure/properties(dissolution/adherence/residual constraints)

    International Nuclear Information System (INIS)

    Demonet, N.

    1998-01-01

    The physico-chemical behavior of porous ceramics depositing is studied in order to use them to favour the biological fixing of hip prosthesis fixed without cement. Alumina depositing, hydroxyapatite depositing and duplex (the both together) have been realized by plasma projection on a substrate in Ti-6Al-V. Tests of dissolution have been made. An original method of sound followed by radioactive tracers has allowed to establish an order of phases degradation and to consider the kinetics of calcium ions in function of several parameters of tests. (N.C.)

  1. Synthesis of few-layer graphene on a Ni substrate by using DC plasma enhanced chemical vapor deposition (PE-CVD)

    International Nuclear Information System (INIS)

    Kim, Jeong Hyuk; Castro, Edward Joseph; Hwang, Yong Gyoo; Lee, Choong Hun

    2011-01-01

    In this work, few-layer graphene (FLG) was successfully grown on polycrystalline Ni a large scale by using DC plasma enhanced chemical vapor deposition (DC PE-CVD), which may serve as an alternative route in large-scale graphene synthesis. The synthesis time had an effect on the quality of the graphene produced. The applied DC voltage, on the other hand, influenced the minimization of the defect densities in the graphene grown. We also present a method of producing a free-standing polymethyl methacrylate (PMMA)/graphene membrane on a FeCl 3(aq) solution, which could then be transferred to the desired substrate.

  2. Improvement of the thickness distribution of a quartz crystal wafer by numerically controlled plasma chemical vaporization machining

    International Nuclear Information System (INIS)

    Shibahara, Masafumi; Yamamura, Kazuya; Sano, Yasuhisa; Sugiyama, Tsuyoshi; Endo, Katsuyoshi; Mori, Yuzo

    2005-01-01

    To improve the thickness uniformity of thin quartz crystal wafer, a new machining process that utilizes an atmospheric pressure plasma was developed. In an atmospheric pressure plasma process, since the kinetic energy of ions that impinge to the wafer surface is small and the density of the reactive species is large, high-efficiency machining without damage is realized, and the thickness distribution is corrected by numerically controlled scanning of the quartz wafer to the localized high-density plasma. By using our developed machining process, the thickness distribution of an AT cut wafer was improved from 174 nm [peak to valley (p-v)] to 67 nm (p-v) within 94 s. Since there are no unwanted spurious modes in the machined quartz wafer, it was proved that the developed machining method has a high machining efficiency without any damage

  3. Fiber-reinforced ceramic matrix composites processed by a hybrid technique based on chemical vapor infiltration, slurry impregnation and spark plasma sintering

    International Nuclear Information System (INIS)

    Magnant, J.; Pailler, R.; Le Petitcorps, Y.; Maille, L.; Guette, A.; Marthe, J.

    2013-01-01

    Fabrication of multidirectional continuous carbon and silicon carbide fiber reinforced ceramic matrix composites (CMC) by a new short time hybrid process was studied. This process is based, first, on the deposition of fiber interphase and coating by chemical vapor infiltration, next, on the introduction of silicon nitride powders into the fibrous preform by slurry impregnation and, finally, on the densification of the composite by liquid phase spark plasma sintering (LP-SPS). The homogeneous introduction of the ceramic charges into the multidirectional fiber pre-forms was realized by slurry impregnation from highly concentrated and well-dispersed aqueous colloid suspensions. The chemical degradation of the carbon fibers during the fabrication was prevented by adapting the sintering pressure cycle. The composites manufactured are dense. Microstructural analyses were conducted to explain the mechanical properties achieved. One main important result of this study is that LP-SPS can be used in some hybrid processes to densify fiber reinforced CMC. (authors)

  4. Effects of boron addition on a-Si90Ge10:H films obtained by low frequency plasma enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Perez, Arllene M; Renero, Francisco J; Zuniga, Carlos; Torres, Alfonso; Santiago, Cesar

    2005-01-01

    Optical, structural and electric properties of (a-(Si 90 Ge 10 ) 1-y B y :H) thin film alloys, deposited by low frequency plasma enhanced chemical vapour deposition, are presented. The chemical bonding structure has been studied by IR spectroscopy, while the composition was investigated by Raman spectroscopy. A discussion about boron doping effects, in the composition and bonding of samples, is presented. Transport of carriers has been studied by measurement of the conductivity dependence on temperature, which increases from 10 -3 to 10 1 Ω -1 cm -1 when the boron content varies from 0 to 50%. Similarly, the activation energy is between 0.62 and 0.19 eV when the doping increases from 0 to 83%. The optical properties have been determined from the film's optical transmission, using Swanepoel's method. It is shown that the optical gap varies from 1.3 to 0.99 eV

  5. A rapid chemical method of labelling human plasma proteins with sup(99m)Tc-pertechnetate at pH 7.4

    International Nuclear Information System (INIS)

    Wong, D.W.; Mishkin, F.; Lee, T.

    1978-01-01

    A successful method for labelling human plasma proteins with sup(99m)Tc-pertechnetate by chemical means is described. The labelling methodology involves the production of Sup(99m)Tc-(Sn)citrate complex species with high protein binding capacity at pH 7.4 condition following initial chemical reduction of sodium sup(99m)Tc-pertechnetate by stannous chloride. A combined labelling efficiency range of 95-99% for sup(99m)Tc-labelled fibrinogen, immune gamma globulin and serum albumin is achieved. The actual amount of labelled protein content in the product is found to be 85-95% when assayed by ITLC and 74-85% by TCAA protein precipitation. In vitro experimental data indicate that sup(99m)Tc-fibrinogen contains an average of 85% clottable protein with an average clottability of 95%. This strongly suggests that the radioactive proteins retain much of their biological and physiological activities after the labelling process. (author)

  6. Wearable Atmospheric Pressure Plasma Fabrics Produced by Knitting Flexible Wire Electrodes for the Decontamination of Chemical Warfare Agents

    OpenAIRE

    Heesoo Jung; Jin Ah Seo; Seungki Choi

    2017-01-01

    One of the key reasons for the limited use of atmospheric pressure plasma (APP) is its inability to treat non-flat, three-dimensional (3D) surface structures, such as electronic devices and the human body, because of the rigid electrode structure required. In this study, a new APP system design?wearable APP (WAPP)?that utilizes a knitting technique to assemble flexible co-axial wire electrodes into a large-area plasma fabric is presented. The WAPP device operates in ambient air with a fully e...

  7. Discharge cleaning on KSTAR 1st plasma events

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, J. G.; Wang, J. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, J. S.; Yang, H. L.; Kim, K. P.; Kim, K. M. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    A discharge cleaning of a vacuum vessel was conducted with a GDC (Glow discharge cleaning) and a ICRF-DC(ICRF assisted discharge cleaning) for the KSTAR first plasma event period. The base pressure of the vessel was kept below 10-7 mbar via a cool down of the cryo-vessel, a 100C baking, and a GDC. (Partial pressure of hydrogen and nitrogen is below 10-8 mbar). The diagnostics for a discharge cleaning is a differential pumped RGA attached to a pumping duct and a cold cathode and a hot cathode gauge attached to the vessel and the pumping duct respectively. To analyze the discharge characteristics, a microwave interferometer, Bremsstahlung, H-alphas and a TV camera were used. Two straps among the four straps of the ICRF antenna are used for the ICRF-DC and ICRF heating experiments. The phase difference between the adjacent straps was 0 degree and the operating frequency was 30-33MHz.

  8. Influence of chemical composition on dielectric properties of Al2O3-ZrO2 plasma deposits

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Sedláček, J.; Neufuss, Karel

    2003-01-01

    Roč. 29, - (2003), s. 527-532 ISSN 0272-8842 R&D Projects: GA ČR GA106/01/0094 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma spray, ceramics, oxides Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 0.704, year: 2003

  9. Synhesis of carbon nanotubes by plasma-enhanced chemical vapor deposition in an atmospheric-pressure microwave torch

    Czech Academy of Sciences Publication Activity Database

    Zajíčková, L.; Jašek, O.; Eliáš, M.; Synek, P.; Lazar, L.; Schneeweiss, Oldřich; Hanzlíková, Renáta

    2010-01-01

    Roč. 82, č. 6 (2010), s. 1259-1272 ISSN 0033-4545 Institutional research plan: CEZ:AV0Z20410507; CEZ:AV0Z20650511 Keywords : carbon * nanotubes * synthesis Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.128, year: 2010

  10. Organosilicon thin films deposited by plasma enhanced CVD:Thermal changes of chemical structure and mechanical properties

    Czech Academy of Sciences Publication Activity Database

    Zajíčková, L.; Buršíková, V.; Kučerová, Z.; Franclová, J.; Siahel, P.; Peřina, Vratislav; Macková, Anna

    2007-01-01

    Roč. 68, 5-6 (2007), s. 1255-1259 ISSN 0022-3697 R&D Projects: GA ČR GA202/07/1669 Institutional research plan: CEZ:AV0Z10480505 Keywords : hin films * organometallic compounds * plasma deposition Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.899, year: 2007

  11. Temporally resolved ozone distribution of a time modulated RF atmospheric pressure argon plasma jet: flow, chemical reaction, and transient vortex

    International Nuclear Information System (INIS)

    Zhang, S; Sobota, A; Van Veldhuizen, E M; Bruggeman, P J

    2015-01-01

    The ozone density distribution in the effluent of a time modulated RF atmospheric pressure plasma jet (APPJ) is investigated by time and spatially resolved by UV absorption spectroscopy. The plasma jet is operated with an averaged dissipated power of 6.5 W and gas flow rate 2 slm argon  +2% O 2 . The modulation frequency of the RF power is 50 Hz with a duty cycle of 50%. To investigate the production and destruction mechanism of ozone in the plasma effluent, the atomic oxygen and gas temperature is also obtained by TALIF and Rayleigh scattering, respectively. A temporal increase in ozone density is observed close to the quartz tube exit when the plasma is switched off due to the decrease in O density and gas temperature. Ozone absorption at different axial positions indicates that the ozone distribution is dominated by the convection induced by the gas flow and allows estimating the on-axis local gas velocity in the jet effluent. Transient vortex structures occurring during the switch on and off of the RF power also significantly affect the ozone density in the far effluent. (paper)

  12. Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles?

    Science.gov (United States)

    Yui, Hiroharu; Banno, Motohiro

    2018-01-01

    In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

  13. Influence of plasma density on the chemical composition and structural properties of pulsed laser deposited TiAlN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Quiñones-Galván, J. G.; Camps, Enrique [Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, México D.F. C.P. 11801 (Mexico); Muhl, S. [Instituto de Investigaciones en Materiales, UNAM, México D.F. C.P. 04510 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, Apdo. Postal 307, C.P. 45101 Zapopan, Jalisco (Mexico); Campos-González, E. [Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, México D.F. 07360 (Mexico)

    2014-05-15

    Incorporation of substitutional Al into the TiN lattice of the ternary alloy TiAlN results in a material with improved properties compared to TiN. In this work, TiAlN thin films were grown by the simultaneous ablation of Ti and Al targets in a nitrogen containing reactive atmosphere. The deposit was formed on silicon substrates at low deposition temperature (200 °C). The dependence of the Al content of the films was studied as a function of the ion density of the plasma produced by the laser ablation of the Al target. The plasma parameters were measured by means of a planar Langmuir probe and optical emission spectroscopy. The chemical composition of the films was measured by energy dispersive X-ray spectroscopy. The results showed a strong dependence of the amount of aluminum incorporated in the films with the plasma density. The structural characterization of the deposits was carried out by Raman spectroscopy, X-ray diffraction, and transmission electron microscopy, where the substitutional incorporation of the Al into the TiN was demonstrated.

  14. Effects of Surface Modification of Nanodiamond Particles for Nucleation Enhancement during Its Film Growth by Microwave Plasma Jet Chemical Vapour Deposition Technique

    Directory of Open Access Journals (Sweden)

    Chii-Ruey Lin

    2014-01-01

    Full Text Available The seedings of the substrate with a suspension of nanodiamond particles (NDPs were widely used as nucleation seeds to enhance the growth of nanostructured diamond films. The formation of agglomerates in the suspension of NDPs, however, may have adverse impact on the initial growth period. Therefore, this paper was aimed at the surface modification of the NDPs to enhance the diamond nucleation for the growth of nanocrystalline diamond films which could be used in photovoltaic applications. Hydrogen plasma, thermal, and surfactant treatment techniques were employed to improve the dispersion characteristics of detonation nanodiamond particles in aqueous media. The seeding of silicon substrate was then carried out with an optimized spin-coating method. The results of both Fourier transform infrared spectroscopy and dynamic light scattering measurements demonstrated that plasma treated diamond nanoparticles possessed polar surface functional groups and attained high dispersion in methanol. The nanocrystalline diamond films deposited by microwave plasma jet chemical vapour deposition exhibited extremely fine grain and high smooth surfaces (~6.4 nm rms on the whole film. These results indeed open up a prospect of nanocrystalline diamond films in solar cell applications.

  15. Effect of Radio-Frequency and Low-Frequency Bias Voltage on the Formation of Amorphous Carbon Films Deposited by Plasma Enhanced Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    Manis-Levy, Hadar; Mintz, Moshe H.; Livneh, Tsachi; Zukerman Ido; Raveh, Avi

    2014-01-01

    The effect of radio-frequency (RF) or low-frequency (LF) bias voltage on the formation of amorphous hydrogenated carbon (a-C:H) films was studied on silicon substrates with a low methane (CH 4 ) concentration (2–10 vol.%) in CH 4 +Ar mixtures. The bias substrate was applied either by RF (13.56 MHz) or by LF (150 kHz) power supply. The highest hardness values (∼18–22 GPa) with lower hydrogen content in the films (∼20 at.%) deposited at 10 vol.% CH 4 , was achieved by using the RF bias. However, the films deposited using the LF bias, under similar RF plasma generation power and CH 4 concentration (50 W and 10 vol.%, respectively), displayed lower hardness (∼6–12 GPa) with high hydrogen content (∼40 at.%). The structures analyzed by Fourier Transform Infrared (FTIR) and Raman scattering measurements provide an indication of trans-polyacetylene structure formation. However, its excessive formation in the films deposited by the LF bias method is consistent with its higher bonded hydrogen concentration and low level of hardness, as compared to the film prepared by the RF bias method. It was found that the effect of RF bias on the film structure and properties is stronger than the effect of the low-frequency (LF) bias under identical radio-frequency (RF) powered electrode and identical PECVD (plasma enhanced chemical vapor deposition) system configuration. (plasma technology)

  16. Quantification of low levels of organochlorine pesticides using small volumes (≤100 μl) of plasma of wild birds through gas chromatography negative chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Rivera-Rodriguez, Laura B.; Rodriguez-Estrella, Ricardo; Ellington, James Jackson; Evans, John J.

    2007-01-01

    A solid phase extraction and gas chromatography with negative chemical ionization mass spectrometry in scan mode (GC-NCI-MS) method was developed to identify and quantify for the first time low levels of organochlorine pesticides (OCs) in plasma samples of less than 100 μl from wild birds. The method detection limits ranged from 0.012 to 0.102 pg/μl and the method reporting limit from 0.036 to 0.307 pg/μl for α, γ, β and δ-hexachlorocyclohexane (HCH), heptachlor, aldrin, heptachlor epoxide, endosulfan I, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), dieldrin, endrin, endosulfan-II, endrin-aldehyde and endosulfan-sulfate. Pesticide levels in small serum samples from individual Falco sparverius, Sturnella neglecta, Mimus polyglottos and Columbina passerina were quantified. Concentrations ranged from not detected (n/d) to 204.9 pg/μl for some OC pesticides. All levels in the food web in and around cultivated areas showed the presence of pesticides notwithstanding the small areas for agriculture existing in the desert of Baja California peninsula. - This technique allows small birds to be used as indicators of chemical contamination in habitats because pesticides can be quantified in very small volumes of plasma

  17. Quantification of low levels of organochlorine pesticides using small volumes ({<=}100 {mu}l) of plasma of wild birds through gas chromatography negative chemical ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rivera-Rodriguez, Laura B. [Centro de Investigaciones Biologicas del Noroeste, S.C., Environmental Planning and Conservation Program, Mar Bermejo No. 195, Col. Playa Palo de Santa Rita, Ado. Postal 128, La Paz, BCS. 23090 (Mexico)]. E-mail: lrivera04@cibnor.mx; Rodriguez-Estrella, Ricardo [Centro de Investigaciones Biologicas del Noroeste, S.C., Environmental Planning and Conservation Program, Mar Bermejo No. 195, Col. Playa Palo de Santa Rita, Ado. Postal 128, La Paz, BCS. 23090 (Mexico); Ellington, James Jackson [National Exposure Research Laboratory, US Environmental Protection Agency, 960 College Station Road, Athens, GA 30605 (United States); Evans, John J. [National Exposure Research Laboratory, US Environmental Protection Agency, 960 College Station Road, Athens, GA 30605 (United States); Senior Service America Inc. (United States)

    2007-07-15

    A solid phase extraction and gas chromatography with negative chemical ionization mass spectrometry in scan mode (GC-NCI-MS) method was developed to identify and quantify for the first time low levels of organochlorine pesticides (OCs) in plasma samples of less than 100 {mu}l from wild birds. The method detection limits ranged from 0.012 to 0.102 pg/{mu}l and the method reporting limit from 0.036 to 0.307 pg/{mu}l for {alpha}, {gamma}, {beta} and {delta}-hexachlorocyclohexane (HCH), heptachlor, aldrin, heptachlor epoxide, endosulfan I, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), dieldrin, endrin, endosulfan-II, endrin-aldehyde and endosulfan-sulfate. Pesticide levels in small serum samples from individual Falco sparverius, Sturnella neglecta, Mimus polyglottos and Columbina passerina were quantified. Concentrations ranged from not detected (n/d) to 204.9 pg/{mu}l for some OC pesticides. All levels in the food web in and around cultivated areas showed the presence of pesticides notwithstanding the small areas for agriculture existing in the desert of Baja California peninsula. - This technique allows small birds to be used as indicators of chemical contamination in habitats because pesticides can be quantified in very small volumes of plasma.

  18. Application of cation-exchange solid-phase extraction for the analysis of amino alcohols from water and human plasma for verification of Chemical Weapons Convention.

    Science.gov (United States)

    Kanaujia, Pankaj K; Tak, Vijay; Pardasani, Deepak; Gupta, A K; Dubey, D K

    2008-03-28

    The analysis of nitrogen containing amino alcohols, which are the precursors and degradation products of nitrogen mustards and nerve agent VX, constitutes an important aspect for verifying the compliance to the CWC (Chemical Weapons Convention). This work devotes on the development of solid-phase extraction method using silica- and polymer-based SCX (strong cation-exchange) and MCX (mixed-mode strong cation-exchange) cartridges for N,N-dialkylaminoethane-2-ols and alkyl N,N-diethanolamines, from water. The extracted analytes were analyzed by GC-MS (gas chromatography-mass spectrometry) in the full scan and selected ion monitoring modes. The extraction efficiencies of SCX and MCX cartridges were compared, and results revealed that SCX performed better. Extraction parameters, such as loading capacity, extraction solvent, its volume, and washing solvent were optimized. Best recoveries were obtained using 2 mL methanol containing 10% NH(4)OH and limits of detection could be achieved up to 5 x 10(-3) microg mL(-1) in the selected ion monitoring mode and 0.01 microg mL(-1) in full scan mode. The method was successfully employed for the detection and identification of amino alcohol present in water sample sent by Organization for Prohibition of Chemical Weapons (OPCW) in the official proficiency tests. The method was also applied to extract the analytes from human plasma. The SCX cartridge showed good recoveries of amino alcohols from human plasma after protein precipitation.

  19. Investigation of deposition characteristics and properties of high-rate deposited silicon nitride films prepared by atmospheric pressure plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Kakiuchi, H.; Nakahama, Y.; Ohmi, H.; Yasutake, K.; Yoshii, K.; Mori, Y.

    2005-01-01

    Silicon nitride (SiN x ) films have been prepared at extremely high deposition rates by the atmospheric pressure plasma chemical vapor deposition (AP-PCVD) technique on Si(001) wafers from gas mixtures containing He, H 2 , SiH 4 and N 2 or NH 3 . A 150 MHz very high frequency (VHF) power supply was used to generate high-density radicals in the atmospheric pressure plasma. Deposition rate, composition and morphology of the SiN x films prepared with various deposition parameters were studied by scanning electron microscopy and Auger electron spectroscopy. Fourier transformation infrared (FTIR) absorption spectroscopy was also used to characterize the structure and the chemical bonding configurations of the films. Furthermore, etching rate with buffered hydrofluoric acid (BHF) solution, refractive index and capacitance-voltage (C-V) characteristics were measured to evaluate the dielectric properties of the films. It was found that effective passivation of dangling bonds and elimination of excessive hydrogen atoms at the film-growing surface seemed to be the most important factor to form SiN x film with a dense Si-N network. The C-V curve of the optimized film showed good interface properties, although further improvement was necessary for use in the industrial metal-insulator-semiconductor (MIS) applications

  20. Effect of additive gases and injection methods on chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F2 remote plasmas

    International Nuclear Information System (INIS)

    Yun, Y. B.; Park, S. M.; Kim, D. J.; Lee, N.-E.; Kim, K. S.; Bae, G. H.

    2007-01-01

    The authors investigated the effects of various additive gases and different injection methods on the chemical dry etching of silicon nitride, silicon oxynitride, and silicon oxide layers in F 2 remote plasmas. N 2 and N 2 +O 2 gases in the F 2 /Ar/N 2 and F 2 /Ar/N 2 /O 2 remote plasmas effectively increased the etch rate of the layers. The addition of direct-injected NO gas increased the etch rates most significantly. NO radicals generated by the addition of N 2 and N 2 +O 2 or direct-injected NO molecules contributed to the effective removal of nitrogen and oxygen in the silicon nitride and oxide layers, by forming N 2 O and NO 2 by-products, respectively, and thereby enhancing SiF 4 formation. As a result of the effective removal of the oxygen, nitrogen, and silicon atoms in the layers, the chemical dry etch rates were enhanced significantly. The process regime for the etch rate enhancement of the layers was extended at elevated temperature

  1. Morphologic and Chemical Properties of PMMA/ATH Layers with Enhanced Abrasion Resistance Realised by Cold Plasma Spraying at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    L. Wallenhorst

    2018-01-01

    Full Text Available This study investigated the morphologic and chemical properties of coatings based on PMMA/ATH powder and deposited by cold plasma spraying on wood and glass. Since the deposition of pure PMMA/ATH powder with air as process gas yielded coatings with insufficient abrasion resistance, two modifications of the basic process were investigated. Previous studies showed that replacing air as process gas with forming gas did not enhance the abrasion resistance, but the addition of a phenol-formaldehyde resin (PF succeeded in stabilising the particle coatings. In this work, results from morphologic and chemical analysis suggested an encasement of the PMMA/ATH particles by plasma-modified PF and thus a fusion of individual particles, explaining the enhanced bonding. Moreover, adhesion tests confirmed an outstanding bonding between the coating and wood as well as glass, which is assumed to result from interactions between the PF’s hydroxyl groups and functional groups on the substrates’ surfaces. Studies on the wettability revealed a hydrophobic character of such coatings, therefore generally indicating a possible application, for example, to reduce water uptake by wooden materials.

  2. High-performance metabolic profiling of plasma from seven mammalian species for simultaneous environmental chemical surveillance and bioeffect monitoring

    OpenAIRE

    Park, Youngja H.; Lee, Kichun; Soltow, Quinlyn A.; Strobel, Frederick H.; Brigham, Kenneth L.; Parker, Richard E.; Wilson, Mark E.; Sutliff, Roy L.; Mansfield, Keith G.; Wachtman, Lynn M.; Ziegler, Thomas R.; Jones, Dean P.

    2012-01-01

    High-performance metabolic profiling (HPMP) by Fourier-transform mass spectrometry coupled to liquid chromatography gives relative quantification of thousands of chemicals in biologic samples but has had little development for use in toxicology research. In principle, the approach could be useful to detect complex metabolic response patterns to toxicologic exposures and to detect unusual abundances or patterns of potentially toxic chemicals. As an initial study to develop these possible uses,...

  3. An Atmospheric Pressure Chemical Ionization MS/MS Assay Using Online Extraction for the Analysis of 11 Cannabinoids and Metabolites in Human Plasma and Urine.

    Science.gov (United States)

    Klawitter, Jelena; Sempio, Cristina; Mörlein, Sophie; De Bloois, Erik; Klepacki, Jacek; Henthorn, Thomas; Leehey, Maureen A; Hoffenberg, Edward J; Knupp, Kelly; Wang, George S; Hopfer, Christian; Kinney, Greg; Bowler, Russell; Foreman, Nicholas; Galinkin, Jeffrey; Christians, Uwe; Klawitter, Jost

    2017-10-01

    Although, especially in the United States, there has been a recent surge of legalized cannabis for either recreational or medicinal purposes, surprisingly little is known about clinical dose-response relationships, pharmacodynamic and toxicodynamic effects of cannabinoids such as Δ9-tetrahydrocannabinol (THC). Even less is known about other active cannabinoids. To address this knowledge gap, an online extraction, high-performance liquid chromatography coupled with tandem mass spectrometry method for simultaneous quantification of 11 cannabinoids and metabolites including THC, 11-hydroxy-Δ9-tetrahydrocannabinol, 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid, 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-C-gluc), cannabinol, cannabidiol, cannabigerol, cannabidivarin, Δ9-tetrahydrocannabivarin (THCV), and 11-nor-9-carboxy-Δ9-tetrahydrocannabivarin (THCV-COOH) was developed and validated in human urine and plasma. In contrast to atmospheric pressure chemical ionization, electrospray ionization was associated with extensive ion suppression in plasma and urine samples. Thus, the atmospheric pressure chemical ionization assay was validated showing a lower limit of quantification ranging from 0.39 to 3.91 ng/mL depending on study compound and matrix. The upper limit of quantification was 400 ng/mL except for THC-C-gluc with an upper limit of quantification of 2000 ng/mL. The linearity was r > 0.99 for all analyzed calibration curves. Acceptance criteria for intrabatch and interbatch accuracy (85%-115%) and imprecision (<15%) were met for all compounds. In plasma, the only exceptions were THCV (75.3%-121.2% interbatch accuracy) and cannabidivarin (interbatch imprecision, 15.7%-17.2%). In urine, THCV did not meet predefined acceptance criteria for intrabatch accuracy. This assay allows for monitoring not only THC and its major metabolites but also major cannabinoids that are of interest for marijuana research and clinical practice.

  4. Lipon thin films grown by plasma-enhanced metalorganic chemical vapor deposition in a N{sub 2}-H{sub 2}-Ar gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Meda, Lamartine, E-mail: LMeda@xula.edu [Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA, 70125 (United States); Maxie, Eleston E. [Excellatron Solid State LLC, 263 Decatur Street, Atlanta, GA 30312 (United States)

    2012-01-01

    Lithium phosphorus oxynitride (Lipon) thin films have been deposited by a plasma-enhanced metalorganic chemical vapor deposition method. Lipon thin films were deposited on approximately 0.2 {mu}m thick Au-coated alumina substrates in a N{sub 2}-H{sub 2}-Ar plasma at 13.56 MHz, a power of 150 W, and at 180 Degree-Sign C using triethyl phosphate [(CH{sub 2}CH{sub 3}){sub 3}PO{sub 4}] and lithium tert-butoxide [(LiOC(CH{sub 3}){sub 3}] precursors. Lipon growth rates ranged from 10 to 42 nm/min and thicknesses varied from 1 to 2.5 {mu}m. X-ray powder diffraction showed that the films were amorphous, and X-ray photoelectron spectroscopy (XPS) revealed approximately 4 at.% N in the films. The ionic conductivity of Lipon was measured by electrochemical impedance spectroscopy to be approximately 1.02 {mu}S/cm, which is consistent with the ionic conductivity of Lipon deposited by radio frequency magnetron sputtering of Li{sub 3}PO{sub 4} targets in either mixed Ar-N{sub 2} or pure N{sub 2} atmosphere. Attempts to deposit Lipon in a N{sub 2}-O{sub 2}-Ar plasma resulted in the growth of Li{sub 3}PO{sub 4} thin films. The XPS analysis shows no C and N atom peaks. Due to the high impedance of these films, reliable conductivity measurements could not be obtained for films grown in N{sub 2}-O{sub 2}-Ar plasma.

  5. Remote plasma enhanced chemical deposition of non-crystalline GeO2 on Ge and Si substrates.

    Science.gov (United States)

    Lucovsky, Gerald; Zeller, Daniel

    2011-09-01

    Non-crystalline GeO2 films remote were plasma deposited at 300 degrees C onto Ge substrates after a final rinse in NH4OH. The reactant precursors gas were: (i) down-stream injected 2% GeH4 in He as the Ge precursor, and (ii) up-stream, plasma excited O2-He mixtures as the O precursor. Films annealed at 400 degrees C displayed no evidence for loss of O resulting in Ge sub-oxide formation, and for a 5-6 eV mid-gap absorption associated with formation of GeOx suboxide bonding, x deposited on Ge and annealed at 600 degrees C and 700 degrees C display spectra indicative of loss of O-atoms, accompanied with a 5.5 eV absorption. X-ray absorption spectroscopy and many-electron theory are combined to describe symmetries and degeneracies for O-vacancy bonding defects. These include comparisons with remote plasma-deposited non-crystalline SiO2 on Si substrates with SiON interfacial layers. Three different properties of remote plasma GeO2 films are addressed comparisons between (i) conduction band and band edge states of GeO2 and SiO2, and (ii) electronic structure of O-atom vacancy defects in GeO2 and SiO2, and differences between (iii) annealing of GeO2 films on Ge substrates, and Si substrates passivated with SiON interfacial transition regions important for device applications.

  6. Blood plasma clinical-chemical parameters as biomarker endpoints for organohalogen contaminant exposure in Norwegian raptor nestlings

    DEFF Research Database (Denmark)

    Sonne, Christian; Bustnes, Jan O.; Herzke, Dorte

    2012-01-01

    Raptors are exposed to biomagnifying and toxic organohalogenated compounds (OHCs) such as organochlorines, brominated flame retardants and perfluorinated compounds. To investigate how OHC exposure may affect biochemical pathways we collected blood plasma from Norwegian northern goshawk (n=56...... it is uncertain if such changes have any health effects. The OHC concentrations were below concentrations causing reproductive toxicity in adults of other raptor species but similar to those of concern for endocrine disruption of thyroid hormones in e.g., bald eagles....

  7. A comparative physico-chemical study of chlorapatite and hydroxyapatite: from powders to plasma sprayed thin coatings.

    Science.gov (United States)

    Demnati, I; Grossin, D; Combes, C; Parco, M; Braceras, I; Rey, C

    2012-10-01

    Due to their bioactivity and osteoconductivity, hydroxyapatite (HA) plasma sprayed coatings have been widely developed for orthopedic uses. However, the thermodynamic instability of HA leads frequently to a mixture of phases which limit the functional durability of the coating. This study investigates the plasma spraying of chlorapatite (ClA) powder, known to melt without decomposition, onto pure titanium substrates using a low energy plasma spray system (LEPS). Pure ClA powder was prepared by a solid gas reaction at 950 °C and thermogravimetric analysis showed the good thermal stability of ClA powder in the range 30-1400 °C compared to that of the HA powder. Characterization of ClA coating showed that ClA had a very high crystalline ratio and no other crystalline phase was detected in the coating. HA and ClA coatings composition, microstructure and in vitro bioactivity potential were studied, compared and discussed. In vitro SBF test on HA and ClA coatings revealed the formation of a poorly crystalline apatite on the coating surface suggesting that we could expect a good osteoconductivity especially for the ClA coating prepared by the LEPS system.

  8. Quantification of monosialogangliosides in human plasma through chemical derivatization for signal enhancement in LC–ESI-MS

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qianyang; Liu, Danting [Clinical Chemistry Program, Department of Chemistry, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115 (United States); Xin, Baozhong; Cechner, Karen [DDC Clinic, Center for Special Needs Children, 14567 Madison Road, Middlefield, OH 44062 (United States); Zhou, Xiang [Clinical Chemistry Program, Department of Chemistry, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115 (United States); Wang, Heng, E-mail: Wang@ddcclinic.org [DDC Clinic, Center for Special Needs Children, 14567 Madison Road, Middlefield, OH 44062 (United States); Zhou, Aimin, E-mail: a.zhou@csuohio.edu [Clinical Chemistry Program, Department of Chemistry, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115 (United States); Center for Gene Regulation in Health and Diseases, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115 (United States)

    2016-07-27

    Gangliosides are found in abundance in the central nervous system of vertebrates. Their metabolic disruption and dysfunction are associated with various neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. In order to improve our understanding of the etiology of these diseases, analytical ganglioside assays with sufficient specificity and sensitivity in relevant biological matrices are required. In the present work we have developed and validated a reverse-phase ultra-performance liquid chromatography (UPLC)/tandem mass spectrometry (MS) method for determining monosialogangliosides GM1, GM2, and GM3 present in human plasma. Compared with our previous method, this method enhanced, by 15 fold, MS responses of the analytes by employing 2-(2-Pyridilamino)-ethylamine (PAEA) & 4-(4, 6-Dimethoxy-1, 3, 5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM)-based derivatization. The analytes and internal standards were derivatized with PAEA&DMTMM after extraction from plasma using a protein precipitation procedure. They were then purified using liquid–liquid partitioning. When the samples were then analyzed by UPLC-MS/MS with a multiple reaction monitoring (MRM) mode, we achieved superior sensitivity and specificity. This method was evaluated for extraction recovery, calibration linearity, precision, accuracy, and lower limit of quantification (LLOQ). The validated method was successfully applied to monitor monosialoganglioside levels in the plasma from patients with GM3 synthase deficiency. With significantly increased sensitivity, we have, for the first time, detected a significant amount of GM3 in the affected patients. - Highlights: • A UPLC/MS/MS method for analyzing monosialogangliosides GM1, GM2, and GM3 in human plasma was developed and validated. • PAEA&DMTMM-based derivatization greatly improved the sensitivity. • The method was applied to measure GM1, GM2, and GM3 in the plasma from the patients with GM3 synthase

  9. Some aspects of plasma thermodynamics

    International Nuclear Information System (INIS)

    Gorgoraki, V.I.

    1986-01-01

    The objective reasons which have inhibited the development of a plasma-thermodynamics theory are discussed and the authors formulate the fundamental principles which can be the basis of a common plasma-thermodynamics theory. Two kinds of thermodynamic equilibrium plasmas are discussed, an isothermal plasma and a nonisothermal plasma. An isothermal plasma is a high-temperature plasma; the Saha-Eggert equation describes its behavior. A nonisothermal plasma is a low-temperature plasma, and the reactions taking place therein are purely plasma-chemical. The ionization equilibrium and the composition of such a plasma can be found with the aid of the equations presented in this paper

  10. Lithium-ions diffusion kinetic in LiFePO4/carbon nanoparticles synthesized by microwave plasma chemical vapor deposition for lithium-ion batteries

    Science.gov (United States)

    Gao, Chao; Zhou, Jian; Liu, Guizhen; Wang, Lin

    2018-03-01

    Olivine structure LiFePO4/carbon nanoparticles are synthesized successfully using a microwave plasma chemical vapor deposition (MPCVD) method. Microwave is an effective method to synthesize nanomaterials, the LiFePO4/carbon nanoparticles with high crystallinity can shorten diffusion routes for ionic transfer and electron tunneling. Meanwhile, a high quality, complete and homogenous carbon layer with appropriate thickness coating on the surface of LiFePO4 particles during in situ chemical vapor deposition process, which can ensure that electrons are able to transfer fast enough from all sides. Electrochemical impedance spectroscopy (EIS) is carried out to collect information about the kinetic behavior of lithium diffusion in LiFePO4/carbon nanoparticles during the charging and discharging processes. The chemical diffusion coefficients of lithium ions, DLi, are calculated in the range of 10-15-10-9 cm2s-1. Nanoscale LiFePO4/carbon particles show the longer regions of the faster solid-solution diffusion, and corresponding to the narrower region of the slower two-phase diffusion during the insertion/exaction of lithium ions. The CV and galvanostatic charge-discharge measurements show that the LiFePO4/carbon nanoparticles perform an excellent electrochemical performance, especially the high rate capacity and cycle life.

  11. Formation of chemical compounds under vacuum plasma-arc deposition of nickel and its alloy onto piezoceramics

    International Nuclear Information System (INIS)

    Grinchenko, V.T.; Lyakhovich, T.K.; Prosina, N.I.; Khromov, S.M.

    1988-01-01

    The phase composition of the transition layer appearing during vacuum-arc coating of nickel and nickel alloy with copper on barium titanate and lead zirconate-titanate is identified. During vacuum plasma-arc coating of nickel and its alloy at the boundary with barium titanate and lead zirconate-titanate the Ni 2 Ti 4 O compound appears which has the crystal lattice type identical with substrate with the parity of lattice parameters. The transition layer contains nickel oxides and NiTiO 3 in the case of barium titanate. When titanate content in substrate increases the zone of reaction diffusion increases in value and becomes more complicate in composition

  12. Effects of pulse frequency of input power on the physical and chemical properties of pulsed streamer discharge plasmas in water

    Czech Academy of Sciences Publication Activity Database

    Ruma, Ruma.; Lukeš, Petr; Aoki, N.; Doležalová, Eva; Hosseini, S.H.R.; Sakugawa, T.; Akiyama, H.

    2013-01-01

    Roč. 46, č. 12 (2013), s. 125202-125202 ISSN 0022-3727 R&D Projects: GA ČR(CZ) GD104/09/H080 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100431203 Program:M Institutional support: RVO:61389021 Keywords : discharge in water * pulsed power * pulse frequency * hydrogen peroxide * organic dye * bacteria * generator * liquids Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.521, year: 2013 http://dx.doi.org/10.1088/0022-3727/46/12/125202

  13. Chemical durability of slag produced by thermal plasma melting of low-level miscellaneous solid wastes. Effects of slag composition

    International Nuclear Information System (INIS)

    Amakawa, Tadashi; Yasui, Shinji

    2001-01-01

    Low-level radioactive miscellaneous solid wastes are generated from commercial operation of nuclear power plants and will be generated from decommissioning of nuclear power plants in future. Static leaching tests were carried out in deionized water of 10degC on slag obtained by thermal plasma melting of simulating materials of the miscellaneous solids wastes with surrogate elements of radionuclides. It is found that logarithm of normalized elemental mass loss from the slag is proportional to the basicity represented by mole fractions of main structural oxides of the slag, such as SiO 2 , Al 2 O 3 , CaO, FeO and MgO. The range of static leaching rates from the slag is determined based on the above results and the basicity range of the miscellaneous solid wastes. Then we compared the leaching rates form the slag and from high level waste glasses. On these grounds, we concluded that the slag obtained by thermal plasma melting of miscellaneous solid wastes can stabilize radio-nuclides in it by no means inferior to the high level waste glasses. (author)

  14. Generation and Role of Reactive Oxygen and Nitrogen Species Induced by Plasma, Lasers, Chemical Agents, and Other Systems in Dentistry

    Science.gov (United States)

    Jha, Nayansi; Ryu, Jae Jun

    2017-01-01

    The generation of reactive oxygen and nitrogen species (RONS) has been found to occur during inflammatory procedures, during cell ischemia, and in various crucial developmental processes such as cell differentiation and along cell signaling pathways. The most common sources of intracellular RONS are the mitochondrial electron transport system, NADH oxidase, and cytochrome P450. In this review, we analyzed the extracellular and intracellular sources of reactive species, their cell signaling pathways, the mechanisms of action, and their positive and negative effects in the dental field. In dentistry, ROS can be found—in lasers, photosensitizers, bleaching agents, cold plasma, and even resin cements, all of which contribute to the generation and prevalence of ROS. Nonthermal plasma has been used as a source of ROS for biomedical applications and has the potential for use with dental stem cells as well. There are different types of dental stem cells, but their therapeutic use remains largely untapped, with the focus currently on only periodontal ligament stem cells. More research is necessary in this area, including studies about ROS mechanisms with dental cells, along with the utilization of reactive species in redox medicine. Such studies will help to provide successful treatment modalities for various diseases. PMID:29204250

  15. Double dielectric barrier (DBD) plasma-assisted deposition of chemical stabilized nanoparticles on polyamide 6,6 and polyester fabrics

    Science.gov (United States)

    Ribeiro, A. I.; Modic, M.; Cvelbar, U.; Dinescu, G.; Mitu, B.; Nikiforov, A.; Leys, C.; Kuchakova, I.; Vanneste, M.; Heyse, P.; De Vrieze, M.; Carneiro, N.; Souto, A. P.; Zille, A.

    2017-10-01

    The development of new multifunctional textiles containing nanoparticles (NPs) has a special interest in several applications for pharmaceutical and medical products. Cu, Zn and Ag are the most promising antimicrobial NPs, exhibiting strong antibacterial activities. However, most of antimicrobial textiles coated with NPs are not able to perform a controlled release of NPs because of the high degree of aggregation. The aim of this study is to assess the effect of NPs stabilizers such as citrate, alginate and polyvinyl alcohol (PVA) in Cu, Zn and Ag NPs dispersions. The obtained dispersions were used to develop a new class of antibacterial NPs coatings onto polyamide 6,6 (PA66) and polyester fabrics (PES) by Double Dielectric Barrier (DBD) plasma discharge. Dynamic light scattering (DLS) was used to evaluate the best dispersing agent in terms of size, polydispersity index and zeta potential. Coating efficiency was evaluated by SEM, XPS and FTIR. The washing fastness of the coatings developed was also tested. The results show that the best dispersions were obtained using 2.5% of citrate for ZnO, 5% Alginate for Cu and 2.5% alginate for Ag NPs. SEM, XPS and FTIR analysis shows that DBD is an efficient deposition technique only for Ag and Cu NPs and that better perform in PA66 than PES fabric. The DBD deposition in air display similar results in term of NPS deposition of usually more efficient plasma jets using carrier gas such as N2 and Ar.

  16. Characteristics of the Arcing Plasma Formation Effect in Spark-Assisted Chemical Engraving of Glass, Based on Machine Vision

    OpenAIRE

    Chao-Ching Ho; Dung-Sheng Wu

    2018-01-01

    Spark-assisted chemical engraving (SACE) is a non-traditional machining technology that is used to machine electrically non-conducting materials including glass, ceramics, and quartz. The processing accuracy, machining efficiency, and reproducibility are the key factors in the SACE process. In the present study, a machine vision method is applied to monitor and estimate the status of a SACE-drilled hole in quartz glass. During the machining of quartz glass, the spring-fed tool electrode was p...

  17. Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Frick, Daniel A., E-mail: dfrick@gfz-potsdam.de [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Schuessler, Jan A. [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Blanckenburg, Friedhelm von [GFZ German Research Centre for Geosciences, 14473 Potsdam (Germany); Institute of Geological Science, Freie Universität Berlin, 12249 Berlin (Germany)

    2016-09-28

    Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ{sup 30}Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ{sup 30}Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the μg g{sup −1}-range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ

  18. Development of routines for simultaneous in situ chemical composition and stable Si isotope ratio analysis by femtosecond laser ablation inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Frick, Daniel A.; Schuessler, Jan A.; Blanckenburg, Friedhelm von

    2016-01-01

    Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition. Here, we evaluate two novel analytical routines for the simultaneous determination of the chemical and Si stable isotope composition (δ 30 Si) on the micrometre scale in geological samples. In both routines, multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) is combined with femtosecond-LA, where stable isotope ratios are corrected for mass bias using standard-sample-bracketing with matrix-independent calibration. The first method is based on laser ablation split stream (LASS), where the laser aerosol is split and introduced simultaneously into both the MC-ICP-MS and a quadrupole ICP-MS. The second method is based on optical emission spectroscopy using direct observation of the MC-ICP-MS plasma (LA-MC-ICP-MS|OES). Both methods are evaluated using international geological reference materials. Accurate and precise Si isotope ratios were obtained with an uncertainty typically better than 0.23‰, 2SD, δ 30 Si. With both methods major element concentrations (e.g., Na, Al, Si, Mg, Ca) can be simultaneously determined. However, LASS-ICP-MS is superior over LA-MC-ICP-MS|OES, which is limited by its lower sensitivity. Moreover, LASS-ICP-MS offers trace element analysis down to the μg g −1 -range for more than 28 elements due to lower limits of detection, and with typical uncertainties better than 15%. For in situ

  19. Microwave Plasma Chemical Vapor Deposition of Nano-Structured Sn/C Composite Thin-Film Anodes for Li-ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Cynthia; Marcinek, M.; Hardwick, L.J.; Richardson, T.J.; Song, X.; Kostecki, R.

    2008-02-01

    In this paper we report results of a novel synthesis method of thin-film composite Sn/C anodes for lithium batteries. Thin layers of graphitic carbon decorated with uniformly distributed Sn nanoparticles were synthesized from a solid organic precursor Sn(IV) tert-butoxide by a one step microwave plasma chemical vapor deposition (MPCVD). The thin-film Sn/C electrodes were electrochemically tested in lithium half cells and produced a reversible capacity of 440 and 297 mAhg{sup -1} at C/25 and 5C discharge rates, respectively. A long term cycling of the Sn/C nanocomposite anodes showed 40% capacity loss after 500 cycles at 1C rate.

  20. Synthesis and analysis of silicon nanowire below Si-Au eutectic temperatures using very high frequency plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Hamidinezhad, Habib; Wahab, Yussof; Othaman, Zulkafli; Ismail, Abd Khamim

    2011-01-01

    Silicon nanowires (SiNWs) were synthesized from pure silane precursor gas and Au nanoparticles catalyst at below Au-Si eutectic temperature. The SiNWs were grown onto Si (1 1 1) substrates using very high frequency plasma enhanced chemical vapor deposition via a vapor-solid-solid mechanism at temperatures ranging from 363 to 230 deg. C. The morphology of the synthesized SiNWs was characterized by means of field emission scanning electron microscope equipped with energy dispersive X-ray, high resolution transmission electron microscopy, X-ray diffraction technique and Raman spectroscope. Results demonstrated that the SiNWs can be grown at the temperature as low as 250 deg. C. In addition, it was revealed that the grown wires were silicon-crystallized.

  1. Microwave plasma enhanced chemical vapor deposition growth of few-walled carbon nanotubes using catalyst derived from an iron-containing block copolymer precursor

    International Nuclear Information System (INIS)

    Wang Peng; Lu, Jennifer; Zhou, Otto

    2008-01-01

    The microwave plasma enhanced chemical vapor deposition (MPECVD) method is now commonly used for directional and conformal growth of carbon nanotubes (CNTs) on supporting substrates. One of the shortcomings of the current process is the lack of control of the diameter and diameter distribution of the CNTs due to difficulties in synthesizing well-dispersed catalysts. Recently, block copolymer derived catalysts have been developed which offer the potential of fine control of both the size of and the spacing between the metal clusters. In this paper we report the successful growth of CNTs with narrow diameter distribution using polystyrene-block-polyferrocenylethylmethylsilane (PS-b-PFEMS) as the catalyst precursor. The study shows that higher growth pressure leads to better CNT growth. Besides the pressure, the effects on the growth of CNTs of the growth parameters, such as temperature and precursor gas ratio, are also studied

  2. Effects of the gate dielectric on the subthreshold transport of carbon nanotube network transistors grown by using plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Jeong, Seung Geun; Park, Wan Jun

    2010-01-01

    In this study, we investigated the subthreshold slope of random network carbon nanotube transistors with different geometries and passivations. Single-wall carbon nanotubes with lengths of 1-2 m were grown by using plasma-enhanced chemical vapor deposition to form the transistor channels. A critical channel length, where the subthreshold slope was saturated, of 7 μm was obtained. This was due to the percolational behavior of the nanotube random networks. With the dielectric passivation, the subthreshold slope was dramatically reduced from 9 V/decade to 0.9 V/decade by reducing interfacial trap sites, which then reduced the interface capacitance between the nanotube network and the gate dielectric.

  3. Tensile test of a silicon microstructure fully coated with submicrometer-thick diamond like carbon film using plasma enhanced chemical vapor deposition method

    Science.gov (United States)

    Zhang, Wenlei; Uesugi, Akio; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Tabata, Osamu

    2017-06-01

    This paper reports the tensile properties of single-crystal silicon (SCS) microstructures fully coated with sub-micrometer thick diamond like carbon (DLC) film using plasma enhanced chemical vapor deposition (PECVD). To minimize the deformations or damages caused by non-uniform coating of DLC, which has high compression residual stress, released SCS specimens with the dimensions of 120 µm long, 4 µm wide, and 5 µm thick were coated from the top and bottom side simultaneously. The thickness of DLC coating is around 150 nm and three different bias voltages were used for deposition. The tensile strength improved from 13.4 to 53.5% with the increasing of negative bias voltage. In addition, the deviation in strength also reduced significantly compared to bare SCS sample.

  4. Levels of oxylipins, endocannabinoids and related lipids in plasma before and after low-level exposure to acrolein in healthy individuals and individuals with chemical intolerance.

    Science.gov (United States)

    Claeson, Anna-Sara; Gouveia-Figueira, Sandra; Häggström, Jenny; Fowler, Christopher J; Nording, Malin L

    2017-06-01

    Oxylipins and endocannabinoids play important biological roles, including effects upon inflammation. It is not known whether the circulating levels of these lipids are affected by inhalation of the environmental pollutant acrolein. In the present study, we have investigated the consequences of low-level exposure to acrolein on oxylipin, endocannabinoid and related lipid levels in the plasma of healthy individuals and individuals with chemical intolerance (CI), an affliction with a suggested inflammatory origin. Participants were exposed twice (60min) to heptane and a mixture of heptane and acrolein. Blood samples were collected before exposure, after and 24h post-exposure. There were no overt effects of acrolein exposure on the oxylipin lipidome or endocannibinoids detectable in the bloodstream at the time points investigated. No relationship between basal levels or levels after exposure to acrolein and CI could be identified. This implicates a minor role of inflammatory mediators on the systemic level in CI. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Role of low density lipoprotein in the activation of plasma lysolecithin acyltransferase activity. Effect of chemical and enzymatic modifications of the lipoprotein on enzyme activity.

    Science.gov (United States)

    Subbaiah, P V; Chen, C H; Bagdade, J D; Albers, J J

    1985-01-01

    The effect of various chemical and enzymatic modifications of low density lipoprotein (LDL) on its ability to activate the isolated human plasma lysolecithin acyltransferase (LAT) was studied. Removal of all lipids from LDL resulted in the complete loss of LAT activation. Removal of only neutral lipids by extraction with heptane retained up to 50% of the original activity, which was not increased further by reconstitution of the LDL with the extracted lipids. Hydrolysis of the diacylphosphoglycerides of the LDL with phospholipases resulted in complete loss of LAT activation which was partially restored by the addition of egg lecithin. Hydrolysis of more than 4% of LDL protein by trypsin led to a linear decrease in activity with complete loss of activity occurring when about 25% of the LDL protein is hydrolyzed. Modification of the arginine groups of LDL reversibly inhibited the activation of LAT. Modification of lysine residues of LDL by acetylation, acetoacetylation or succinylation also abolished its ability to activate lysolecithin acylation.

  6. Influence of boron concentration on growth characteristic and electro-catalytic performance of boron-doped diamond electrodes prepared by direct current plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Feng Yujie; Lv Jiangwei; Liu Junfeng; Gao Na; Peng Hongyan; Chen Yuqiang

    2011-01-01

    A series of boron-doped diamond (BDD) electrodes were prepared by direct current plasma chemical vapor deposition (DC-PCVD) with different compositions of CH 4 /H 2 /B(OCH 3 ) 3 gas mixture. A maximum growth rate of 0.65 mg cm -2 h -1 was obtained with CH 4 /H 2 /B(OCH 3 ) 3 radio of 4/190/10 and this growth condition was also a turning point for discharge plasma stability which arose from the addition of B(OCH 3 ) 3 that changed electron energy distribution and influenced the plasma reaction. The surface coating structure and electro-catalytic performance of the BDD electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, Hall test, and electrochemical measurement and electro-catalytic oxidation in phenol solution. It is suggested that the boron doping level and the thermal stress in the films are the main factors affecting the electro-catalytic characteristics of the electrodes. Low boron doping level with CH 4 /H 2 /B(OCH 3 ) 3 ratio of 4/199/1 decreased the films electrical conductivity and its electro-catalytic activity. When the carrier concentration in the films reached around 10 20 cm -3 with CH 4 /H 2 /B(OCH 3 ) 3 ratio over a range of 4/195/5-4/185/15, the thermal stress in the films was the key reason that influenced the electro-catalytic activity of the electrodes for its effect on diamond lattice expansion. Therefore, the BDD electrode with modest CH 4 /H 2 /B(OCH 3 ) 3 ratio of 4/190/10 possessed the best phenol removal efficiency.

  7. Morphological and optical properties changes in nanocrystalline Si (nc-Si) deposited on porous aluminum nanostructures by plasma enhanced chemical vapor deposition for Solar energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ghrib, M., E-mail: mondherghrib@yahoo.fr [Laboratoire de Photovoltaique (L.P.V.), Centre de Recherche et des Technologies de l' Energie, BP 95, Hammam-Lif 2050 (Tunisia); Gaidi, M.; Ghrib, T.; Khedher, N. [Laboratoire de Photovoltaique (L.P.V.), Centre de Recherche et des Technologies de l' Energie, BP 95, Hammam-Lif 2050 (Tunisia); Ben Salam, M. [L3M, Department of Physics, Faculty of Sciences of Bizerte, 7021 Zarzouna (Tunisia); Ezzaouia, H. [Laboratoire de Photovoltaique (L.P.V.), Centre de Recherche et des Technologies de l' Energie, BP 95, Hammam-Lif 2050 (Tunisia)

    2011-08-15

    Photoluminescence (PL) spectroscopy was used to determine the electrical band gap of nanocrystalline silicon (nc-Si) deposited by plasma enhancement chemical vapor deposition (PECVD) on porous alumina structure by fitting the experimental spectra using a model based on the quantum confinement of electrons in Si nanocrystallites having spherical and cylindrical forms. This model permits to correlate the PL spectra to the microstructure of the porous aluminum silicon layer (PASL) structure. The microstructure of aluminum surface layer and nc-Si films was systematically studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction (XRD). It was found that the structure of the nanocrystalline silicon layer (NSL) is dependent of the porosity (void) of the porous alumina layer (PAL) substrate. This structure was performed in two steps, namely the PAL substrate was prepared using sulfuric acid solution attack on an Al foil and then the silicon was deposited by plasma enhanced chemical vapor deposition (PECVD) on it. The optical constants (n and k as a function of wavelength) of the deposited films were obtained using variable angle spectroscopic ellipsometry (SE) in the UV-vis-NIR regions. The SE spectrum of the porous aluminum silicon layer (PASL) was modeled as a mixture of void, crystalline silicon and aluminum using the Cauchy model approximation. The specific surface area (SSA) was estimated and was found to decrease linearly when porosity increases. Based on this full characterization, it is demonstrated that the optical characteristics of the films are directly correlated to their micro-structural properties.

  8. Morphological and optical properties changes in nanocrystalline Si (nc-Si) deposited on porous aluminum nanostructures by plasma enhanced chemical vapor deposition for Solar energy applications

    International Nuclear Information System (INIS)

    Ghrib, M.; Gaidi, M.; Ghrib, T.; Khedher, N.; Ben Salam, M.; Ezzaouia, H.

    2011-01-01

    Photoluminescence (PL) spectroscopy was used to determine the electrical band gap of nanocrystalline silicon (nc-Si) deposited by plasma enhancement chemical vapor deposition (PECVD) on porous alumina structure by fitting the experimental spectra using a model based on the quantum confinement of electrons in Si nanocrystallites having spherical and cylindrical forms. This model permits to correlate the PL spectra to the microstructure of the porous aluminum silicon layer (PASL) structure. The microstructure of aluminum surface layer and nc-Si films was systematically studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction (XRD). It was found that the structure of the nanocrystalline silicon layer (NSL) is dependent of the porosity (void) of the porous alumina layer (PAL) substrate. This structure was performed in two steps, namely the PAL substrate was prepared using sulfuric acid solution attack on an Al foil and then the silicon was deposited by plasma enhanced chemical vapor deposition (PECVD) on it. The optical constants (n and k as a function of wavelength) of the deposited films were obtained using variable angle spectroscopic ellipsometry (SE) in the UV-vis-NIR regions. The SE spectrum of the porous aluminum silicon layer (PASL) was modeled as a mixture of void, crystalline silicon and aluminum using the Cauchy model approximation. The specific surface area (SSA) was estimated and was found to decrease linearly when porosity increases. Based on this full characterization, it is demonstrated that the optical characteristics of the films are directly correlated to their micro-structural properties.

  9. Determination of iodine at ppt level in a nitric acid medium by inductively coupled plasma sector field mass spectrometry: influence of the chemical forms

    International Nuclear Information System (INIS)

    Langlois, B.

    2001-01-01

    Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP/SFMS) was used to determine several chemical forms of iodine, at ppt level, in a nitric acid media. Ascorbic acid was added as a reducing agent in order to maintain iodine as iodide. In a preliminary approach, the influence of the chemical form was studied by comparing inorganic iodine (NaI) and organic iodine (CH3I). Different signal responses were observed. With a conventional sample introduction system, sensitivities obtained for iodo-methane could differ by a factor of 5. This was not caused by a problem of atomization or by a change in the ionization efficiency of the iodo-compound into the plasma. The low volatilization temperature of iodo-methane (315.5 K) seemed to be the main explanation of this phenomena. Actually, nebulization resulted in the volatilization of a 2% nitric acid solution containing iodo-methane. As a result, the transport efficiency of iodo-methane between the nebulizer and the torch was approaching 100%. A Direct Injection High Efficiency Nebulizer (DIHEN) allowed us to minimize the behavior difference between the two iodine species, but the sensitivity ratio was inverted and still differed by 20 - 40%. Moreover, the association of a guard electrode and the direct injection system was studied in order to apply these equipments to the determination of iodine. This association allowed us to improve the sensitivity by a factor of 10 and to minimize memory effects, when compared with a conventional system. Further studies indicated that signal responses obtained with different iodine-containing species, except for iodo-methane, were found to be similar. (author)

  10. Performance Improvement of Microcrystalline p-SiC/i-Si/n-Si Thin Film Solar Cells by Using Laser-Assisted Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The microcrystalline p-SiC/i-Si/n-Si thin film solar cells treated with hydrogen plasma were fabricated at low temperature using a CO2 laser-assisted plasma enhanced chemical vapor deposition (LAPECVD system. According to the micro-Raman results, the i-Si films shifted from 482 cm−1 to 512 cm−1 as the assisting laser power increased from 0 W to 80 W, which indicated a gradual transformation from amorphous to crystalline Si. From X-ray diffraction (XRD results, the microcrystalline i-Si films with (111, (220, and (311 diffraction were obtained. Compared with the Si-based thin film solar cells deposited without laser assistance, the short-circuit current density and the power conversion efficiency of the solar cells with assisting laser power of 80 W were improved from 14.38 mA/cm2 to 18.16 mA/cm2 and from 6.89% to 8.58%, respectively.

  11. Metal/Carbon Hybrid Nanostructures Produced from Plasma-Enhanced Chemical Vapor Deposition over Nafion-Supported Electrochemically Deposited Cobalt Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Islam

    2018-04-01

    Full Text Available In this work, we report development of hybrid nanostructures of metal nanoparticles (NP and carbon nanostructures with strong potential for catalysis, sensing, and energy applications. First, the etched silicon wafer substrates were passivated for subsequent electrochemical (EC processing through grafting of nitro phenyl groups using para-nitrobenzene diazonium (PNBT. The X-ray photoelectron spectroscope (XPS and atomic force microscope (AFM studies confirmed presence of few layers. Cobalt-based nanoparticles were produced over dip or spin coated Nafion films under different EC reduction conditions, namely CoSO4 salt concentration (0.1 M, 1 mM, reduction time (5, 20 s, and indirect or direct EC reduction route. Extensive AFM examination revealed NP formation with different attributes (size, distribution depending on electrochemistry conditions. While relatively large NP with >100 nm size and bimodal distribution were obtained after 20 s EC reduction in H3BO3 following Co2+ ion uptake, ultrafine NP (<10 nm could be produced from EC reduction in CoSO4 and H3BO3 mixed solution with some tendency to form oxides. Different carbon nanostructures including few-walled or multiwalled carbon nanotubes (CNT and carbon nanosheets were grown in a C2H2/NH3 plasma using the plasma-enhanced chemical vapor deposition technique. The devised processing routes enable size controlled synthesis of cobalt nanoparticles and metal/carbon hybrid nanostructures with unique microstructural features.

  12. Modified DLC coatings prepared in a large-scale reactor by dual microwave/pulsed-DC plasma-activated chemical vapour deposition

    International Nuclear Information System (INIS)

    Corbella, C.; Bialuch, I.; Kleinschmidt, M.; Bewilogua, K.

    2008-01-01

    Diamond-Like Carbon (DLC) films find abundant applications as hard and protective coatings due to their excellent mechanical and tribological performances. The addition of new elements to the amorphous DLC matrix tunes the properties of this material, leading to an extension of its scope of applications. In order to scale up their production to a large plasma reactor, DLC films modified by silicon and oxygen additions have been grown in an industrial plant of 1m 3 by means of pulsed-DC plasma-activated chemical vapour deposition (PACVD). The use of an additional microwave (MW) source has intensified the glow discharge, partly by electron cyclotron resonance (ECR), accelerating therefore the deposition process. Hence, acetylene, tetramethylsilane (TMS) and hexamethyldisiloxane (HMDSO) constituted the respective gas precursors for the deposition of a-C:H (DLC), a-C:H:Si and a-C:H:Si:O films by dual MW/pulsed-DC PACVD. This work presents systematic studies of the deposition rate, hardness, adhesion, abrasive wear and water contact angle aimed to optimize the technological parameters of deposition: gas pressure, relative gas flow of the monomers and input power. This study has been completed with measures of the atomic composition of the samples. Deposition rates around 1 μm/h, typical for standard processes held in the large reactor, were increased about by a factor 10 when the ionization source has been operated in ECR mode

  13. Pressure dependence of morphology and phase composition of SiC films deposited by microwave plasma chemical vapor deposition on cemented carbide substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yu Shengwang, E-mail: bkdysw@yahoo.cn; Fan Pengwei; Tang Weizhong; Li Xiaojing; Hu Haolin; Hei Hongjun; Zhang Sikai; Lu Fanxiu

    2011-11-01

    SiC films were deposited on cemented carbide substrates by employing microwave plasma chemical vapor deposition method using tetramethylsilane (Si(CH{sub 3}){sub 4}) diluted in H{sub 2} as the precursor. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and scratching technique were used to characterize morphology, composition, phases present and adhesion of the films. Experimental results show that the deposition pressure has great influence on morphologies and phase composition of the films. In sequence, SiC films with a cauliflower-like microstructure, granular films with terrace-featured SiC particles coexisting with Co{sub 2}Si compound and clusters of nanometer SiC nanoplatelets appear as a function of the deposition pressure. In terms of plasma density and substrate temperature, this sequential appearance of microstructures of SiC films was explained. Adhesion tests showed that among the three types of films studied, the films with the terrace-featured SiC particles have relatively higher adhesion. Such knowledge will be of importance when the SiC films are used as interlayer between diamond films and cemented carbide substrates.

  14. Pressure dependence of morphology and phase composition of SiC films deposited by microwave plasma chemical vapor deposition on cemented carbide substrates

    International Nuclear Information System (INIS)

    Yu Shengwang; Fan Pengwei; Tang Weizhong; Li Xiaojing; Hu Haolin; Hei Hongjun; Zhang Sikai; Lu Fanxiu

    2011-01-01

    SiC films were deposited on cemented carbide substrates by employing microwave plasma chemical vapor deposition method using tetramethylsilane (Si(CH 3 ) 4 ) diluted in H 2 as the precursor. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and scratching technique were used to characterize morphology, composition, phases present and adhesion of the films. Experimental results show that the deposition pressure has great influence on morphologies and phase composition of the films. In sequence, SiC films with a cauliflower-like microstructure, granular films with terrace-featured SiC particles coexisting with Co 2 Si compound and clusters of nanometer SiC nanoplatelets appear as a function of the deposition pressure. In terms of plasma density and substrate temperature, this sequential appearance of microstructures of SiC films was explained. Adhesion tests showed that among the three types of films studied, the films with the terrace-featured SiC particles have relatively higher adhesion. Such knowledge will be of importance when the SiC films are used as interlayer between diamond films and cemented carbide substrates.

  15. Chemical vapor deposition of SiC on C-C composites as plasma facing materials for fusion application

    International Nuclear Information System (INIS)

    Kim, W. J.; Lee, M. Y.; Park, J. Y.; Hong, G. W.; Kim, J. I.; Choi, D. J.

    2000-01-01

    Because of the low activation and excellent mechanical properties at elevated temperatures, carbon-fiber reinforced carbon(C-C) composites have received much attention for plasma facing materials for fusion reactor and high-temperature structural applications such as aircrafts and space vehicles. These proposed applications have been frustrated by the lack of resistance to hydrogen erosion and oxidation on exposure to ambient oxidizing conditions at high temperature. Although Silicon Carbide (SiC) has shown excellent properties as an effective erosion-and oxidation-protection coating, many cracks are developed during fabrication and thermal cycles in use due to the Coefficients of Thermal Expansion(CTE) mismatch between SiC and C-C composite. In this study, we adopted a pyrolitic carbon as an interlayer between SiC and C-C substrate in order to minimize the CTE mismatch. The oxidation-protection performance of this composite was investigated as well

  16. Thin films of hydrogenated amorphous carbon (a-C:H) obtained through chemical vapor deposition assisted by plasma

    International Nuclear Information System (INIS)

    Mejia H, J.A.; Camps C, E.E.; Escobar A, L.; Romero H, S.; Chirino O, S.; Muhl S, S.

    2004-01-01

    Films of hydrogenated amorphous carbon (a-C:H) were deposited using one source of microwave plasma with magnetic field (type ECR), using mixtures of H 2 /CH 4 in relationship of 80/20 and 95/05 as precursory gases, with work pressures of 4X10 -4 to 6x10 -4 Torr and an incident power of the discharge of microwaves with a constant value of 400 W. It was analyzed the influence among the properties of the films, as the deposit rate, the composition and the bonding types, and the deposit conditions, such as the flow rates of the precursory gases and the polarization voltage of the sample holders. (Author)

  17. Plasma-chemical synthesis of carbon nanotubes and fullerenes to create frost-resistant composite building materials

    International Nuclear Information System (INIS)

    Semenov, A P; Smirnyagina, N N; Tsyrenov, B O; Dasheev, D E; Khaltarov, Z M

    2017-01-01

    This paper considers a method of synthesis fullerenes and carbon nanotubes at atmospheric pressure. Carbon evaporates into the plasma arc. The paper discusses the method of synthesis of helium at a pressure of 10 5 Pa. We show the dependence yield of fullerenes and carbon nanotubes from the buffer gas pressure. It has been found that the fullerene yield increased with increasing pressure. The obtained fullerenes and nanotubes find their application in the modification of construction materials. The use of carbon nanomodifiers in the modification of the construction is promising since their introduction significantly improves the physico-mechanical properties using a small quantity of additives. With the introduction of the carbon nanomodifier decrease the porosity of cement stone, which leads to high strength and frost-resistant indicators of the modified cement. (paper)

  18. Infrared and Raman spectroscopy study of AsS chalcogenide films prepared by plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Mochalov, Leonid; Dorosz, Dominik; Kudryashov, Mikhail; Nezhdanov, Aleksey; Usanov, Dmitry; Gogova, Daniela; Zelentsov, Sergey; Boryakov, Aleksey; Mashin, Alexandr

    2018-03-15

    AsS chalcogenide films, where As content is 60-40at.%, have been prepared via a RF non-equilibrium low-temperature argon plasma discharge, using volatile As and S as the precursors. Optical properties of the films were studied in UV-visible-NIR region in the range from 0.2 to 2.5μm. Infrared and Raman spectroscopy have been employed for the elucidation of the molecular structure of the newly developed material. It was established that PECVD films possess a higher degree of transparency (up to 80%) and a wider transparency window (>20μm) in comparison with the "usual" AsS thin films, prepared by different thermal methods, which is highly advantageous for certain applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Time-resolved investigation of the surface chemical modification of poly(ethylene naphthalate) by nitrogen plasma treatment

    International Nuclear Information System (INIS)

    Grace, J.M.; Zhuang, H.K.; Gerenser, L.J.; Freeman, D.R.

    2003-01-01

    A low rf nitrogen plasma source was used to treat poly(ethylene-2, 6-naphthalate) web material. Nitrogen uptake, the N 1s centroid, the N 1s peak width, rearrangement of the ester (from the O 1s spectrum), and oxygen level were measured using x-ray photoelectron spectroscopy as a function of treatment time at several treatment conditions. The observed changes in surface chemistry with treatment time are roughly consistent with a dose response having a linear regime at low doses and a saturation regime at high doses (where dose is power/width/web speed). Hence, to a first approximation, the flux densities (to the web) of relevant species scale with power. As the dose increases, the distribution of nitrogen groups formed broadens and shifts toward higher N 1s binding energy, suggesting that a larger fraction of the nitrogen-containing species are amines at low doses and amides at higher doses. The breadth of the distribution of nitrogen-containing species appears to be strongly correlated with the amount of nitrogen incorporated in the PEN surface. A surface sites model was applied to the measured nitrogen uptake as a function of treatment time. Phenomenological nitrogen incorporation and loss terms were determined in the context of this model. Both terms increase with treatment power and treatment pressure. The ratio, however, varies to a much smaller degree as a function of process conditions, with high powers and pressures giving the highest ratio. Further elucidation of the incorporation and loss processes should be possible with plasma diagnostic data related to species concentrations

  20. Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Fa-Kuei Tung

    2009-01-01

    Full Text Available Direct and facile method to make carbon nanotube (CNT tips for scanning tunneling microscopy (STM is presented. Cobalt (Co particles, as catalysts, are electrochemically deposited on the apex of tungsten (W STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD. A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

  1. Carbon diffusion in uncoated and titanium nitride coated iron substrates during microwave plasma assisted chemical vapor deposition of diamond

    International Nuclear Information System (INIS)

    Weiser, P.S.; Prawer, S.; Manory, R.R.; Paterson, P.J.K.; Stuart, Sue-Anne

    1992-01-01

    Auger Electron Spectroscopy has been employed to investigate the effectiveness of thin films of TiN as barriers to carbon diffusion during Chemical Vapor Deposition (CVD) of diamond onto Fe substrates. Auger Depth Profiling was used to monitor the C concentration in the TiN layer, through the interface and into the substrate both before and after CVD diamond deposition. The results show that a layer of TiN only 250 Angstroems thick is sufficient to inhibit soot formation on the Fe surface and C diffusion into the Fe bulk. 14 refs., 4 figs

  2. The Surface Interface Characteristics of Vertically Aligned Carbon Nanotube and Graphitic Carbon Fiber Arrays Grown by Thermal and Plasma Enhanced Chemical Vapor Deposition

    Science.gov (United States)

    Delzeit, Lance; Nguyen, Cattien; Li, Jun; Han, Jie; Meyyappan, M.

    2002-01-01

    The development of nano-arrays for sensors and devices requires the growth of arrays with the proper characteristics. One such application is the growth of vertically aligned carbon nanotubes (CNTs) and graphitic carbon fibers (GCFs) for the chemical attachment of probe molecules. The effectiveness of such an array is dependent not only upon the effectiveness of the probe and the interface between that probe and the array, but also the array and the underlaying substrate. If that array is a growth of vertically aligned CNTs or GCFs then the attachment of that array to the surface is of the utmost importance. This attachment provides the mechanical stability and durability of the array, as well as, the electrical properties of that array. If the detection is to be acquired through an electrical measurement, then the appropriate resistance between the array and the surface need to be fabricated into the device. I will present data on CNTs and GCFs grown from both thermal and plasma enhanced chemical vapor deposition. The focus will be on the characteristics of the metal film from which the CNTs and GCFs are grown and the changes that occur due to changes within the growth process.

  3. Effects of boron addition on a-Si(90)Ge(10):H films obtained by low frequency plasma enhanced chemical vapour deposition.

    Science.gov (United States)

    Pérez, Arllene M; Renero, Francisco J; Zúñiga, Carlos; Torres, Alfonso; Santiago, César

    2005-06-29

    Optical, structural and electric properties of (a-(Si(90)Ge(10))(1-y)B(y):H) thin film alloys, deposited by low frequency plasma enhanced chemical vapour deposition, are presented. The chemical bonding structure has been studied by IR spectroscopy, while the composition was investigated by Raman spectroscopy. A discussion about boron doping effects, in the composition and bonding of samples, is presented. Transport of carriers has been studied by measurement of the conductivity dependence on temperature, which increases from 10(-3) to 10(1) Ω(-1) cm(-1) when the boron content varies from 0 to 50%. Similarly, the activation energy is between 0.62 and 0.19 eV when the doping increases from 0 to 83%. The optical properties have been determined from the film's optical transmission, using Swanepoel's method. It is shown that the optical gap varies from 1.3 to 0.99 eV.

  4. Optimization of Gas Composition Used in Plasma Chemical Vaporization Machining for Figuring of Reaction-Sintered Silicon Carbide with Low Surface Roughness.

    Science.gov (United States)

    Sun, Rongyan; Yang, Xu; Ohkubo, Yuji; Endo, Katsuyoshi; Yamamura, Kazuya

    2018-02-05

    In recent years, reaction-sintered silicon carbide (RS-SiC) has been of interest in many engineering fields because of its excellent properties, such as its light weight, high rigidity, high heat conductance and low coefficient of thermal expansion. However, RS-SiC is difficult to machine owing to its high hardness and chemical inertness and because it contains multiple components. To overcome the problem of the poor machinability of RS-SiC in conventional machining, the application of atmospheric-pressure plasma chemical vaporization machining (AP-PCVM) to RS-SiC was proposed. As a highly efficient and damage-free figuring technique, AP-PCVM has been widely applied for the figuring of single-component materials, such as Si, SiC, quartz crystal wafers, and so forth. However, it has not been applied to RS-SiC since it is composed of multiple components. In this study, we investigated the AP-PCVM etching characteristics for RS-SiC by optimizing the gas composition. It was found that the different etching rates of the different components led to a large surface roughness. A smooth surface was obtained by applying the optimum gas composition, for which the etching rate of the Si component was equal to that of the SiC component.

  5. Metabolomics analysis reveals elevation of 3-indoxyl sulfate in plasma and brain during chemically-induced acute kidney injury in mice: Investigation of nicotinic acid receptor agonists

    International Nuclear Information System (INIS)

    Zgoda-Pols, Joanna R.; Chowdhury, Swapan; Wirth, Mark; Milburn, Michael V.; Alexander, Danny C.; Alton, Kevin B.

    2011-01-01

    An investigative renal toxicity study using metabolomics was conducted with a potent nicotinic acid receptor (NAR) agonist, SCH 900424. Liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) techniques were used to identify small molecule biomarkers of acute kidney injury (AKI) that could aid in a better mechanistic understanding of SCH 900424-induced AKI in mice. The metabolomics study revealed 3-indoxyl sulfate (3IS) as a more sensitive marker of SCH 900424-induced renal toxicity than creatinine or urea. An LC-MS assay for quantitative determination of 3IS in mouse matrices was also developed. Following treatment with SCH 900424, 3IS levels were markedly increased in murine plasma and brain, thereby potentially contributing to renal- and central nervous system (CNS)-related rapid onset of toxicities. Furthermore, significant decrease in urinary excretion of 3IS in those animals due to compromised renal function may be associated with the elevation of 3IS in plasma and brain. These data suggest that 3IS has a potential to be a marker of renal and CNS toxicities during chemically-induced AKI in mice. In addition, based on the metabolomic analysis other statistically significant plasma markers including p-cresol-sulfate and tryptophan catabolites (kynurenate, kynurenine, 3-indole-lactate) might be of toxicological importance but have not been studied in detail. This comprehensive approach that includes untargeted metabolomic and targeted bioanalytical sample analyses could be used to investigate toxicity of other compounds that pose preclinical or clinical development challenges in a pharmaceutical discovery and development. - Research highlights: → Nicotinic acid receptor agonist, SCH 900424, caused acute kidney injury in mice. → MS-based metabolomics was conducted to identify potential small molecule markers of renal toxicity. → 3-indoxyl-sulfate was found to be as a more sensitive marker of renal toxicity than

  6. Ge/Si (100) heterojunction photodiodes fabricated from material grown by low-energy plasma-enhanced chemical vapour deposition

    International Nuclear Information System (INIS)

    Osmond, Johann; Isella, Giovanni; Chrastina, Daniel; Kaufmann, Rolf; Kaenel, Hans von

    2008-01-01

    We have fabricated a series of p-i-n Ge/Si heterojunction photodetectors with different thicknesses of the intrinsic Ge layer, different doping levels of the p and n layers and different diode diameters. Epitaxial Ge was deposited on Si(100) using low-energy plasma-enhanced CVD (LEPECVD) followed by cyclic annealing. Dark current values as low as 0.04 mA/cm 2 were achieved for 1 μm thick p-i-n photodiodes on lightly doped substrates at - 1 V bias, and external quantum efficiencies of 56% at 1.30 μm and 44% at 1.55 μm for 3 μm thick p + -i-n + photodiodes on highly doped substrates under 0.5 V reverse bias. For a 30 μm diameter diode a RC frequency of 21 GHz is obtained at a reverse bias of 1 V. With such characteristics, these diodes are attractive for telecommunication and optoelectronic applications

  7. Plasma technology

    International Nuclear Information System (INIS)

    Drouet, M.G.

    1984-03-01

    IREQ was contracted by the Canadian Electrical Association to review plasma technology and assess the potential for application of this technology in Canada. A team of experts in the various aspects of this technology was assembled and each team member was asked to contribute to this report on the applications of plasma pertinent to his or her particular field of expertise. The following areas were examined in detail: iron, steel and strategic-metals production; surface treatment by spraying; welding and cutting; chemical processing; drying; and low-temperature treatment. A large market for the penetration of electricity has been identified. To build up confidence in the technology, support should be provided for selected R and D projects, plasma torch demonstrations at full power, and large-scale plasma process testing

  8. Plasma in wound healing

    NARCIS (Netherlands)

    Tipa, R.S.

    2012-01-01

    Plasmas, due to their electrical and chemical properties, release in the invironment a unique cocktail of charged species, energetic photons and active radicals. Plasmas have a miriad of applications. To mention just a few, plasmas are being used in the semiconductors industry, atomic layer

  9. Plasma processing and chemistry

    NARCIS (Netherlands)

    Schram, D.C.; Mullen, van der J.J.A.M.; Sanden, van de M.C.M.

    1994-01-01

    The growing field of applications of plasma as deposition, etching, surface modification and chemical conversion has stimulated a renewed interest in plasma science in the atomic physical chemistry regime. The necessity to optimize the various plasma processing techniques in terms of rates, and

  10. Characteristics of the Arcing Plasma Formation Effect in Spark-Assisted Chemical Engraving of Glass, Based on Machine Vision.

    Science.gov (United States)

    Ho, Chao-Ching; Wu, Dung-Sheng

    2018-03-22

    Spark-assisted chemical engraving (SACE) is a non-traditional machining technology that is used to machine electrically non-conducting materials including glass, ceramics, and quartz. The processing accuracy, machining efficiency, and reproducibility are the key factors in the SACE process. In the present study, a machine vision method is applied to monitor and estimate the status of a SACE-drilled hole in quartz glass. During the machining of quartz glass, the spring-fed tool electrode was pre-pressured on the quartz glass surface to feed the electrode that was in contact with the machining surface of the quartz glass. In situ image acquisition and analysis of the SACE drilling processes were used to analyze the captured image of the state of the spark discharge at the tip and sidewall of the electrode. The results indicated an association between the accumulative size of the SACE-induced spark area and deepness of the hole. The results indicated that the evaluated depths of the SACE-machined holes were a proportional function of the accumulative spark size with a high degree of correlation. The study proposes an innovative computer vision-based method to estimate the deepness and status of SACE-drilled holes in real time.

  11. Characteristics of the Arcing Plasma Formation Effect in Spark-Assisted Chemical Engraving of Glass, Based on Machine Vision

    Directory of Open Access Journals (Sweden)

    Chao-Ching Ho

    2018-03-01

    Full Text Available Spark-assisted chemical engraving (SACE is a non-traditional machining technology that is used to machine electrically non-conducting materials including glass, ceramics, and quartz. The processing accuracy, machining efficiency, and reproducibility are the key factors in the SACE process. In the present study, a machine vision method is applied to monitor and estimate the status of a SACE-drilled hole in quartz glass. During the machining of quartz glass, the spring-fed tool electrode was pre-pressured on the quartz glass surface to feed the electrode that was in contact with the machining surface of the quartz glass. In situ image acquisition and analysis of the SACE drilling processes were used to analyze the captured image of the state of the spark discharge at the tip and sidewall of the electrode. The results indicated an association between the accumulative size of the SACE-induced spark area and deepness of the hole. The results indicated that the evaluated depths of the SACE-machined holes were a proportional function of the accumulative spark size with a high degree of correlation. The study proposes an innovative computer vision-based method to estimate the deepness and status of SACE-drilled holes in real time.

  12. Optical and passivating properties of hydrogenated amorphous silicon nitride deposited by plasma enhanced chemical vapour deposition for application on silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wight, Daniel Nilsen

    2008-07-01

    Within this thesis, several important subjects related to the use of amorphous silicon nitride made by plasma enhanced chemical vapour deposition as an anti-reflective coating on silicon solar cells are presented. The first part of the thesis covers optical simulations to optimise single and double layer anti-reflective coatings with respect to optical performance when situated on a silicon solar cell. The second part investigates the relationship between important physical properties of silicon nitride films when deposited under different conditions. The optical simulations were either based on minimising the reflectance off a silicon nitride/silicon wafer stack or maximising the transmittance through the silicon nitride into the silicon wafer. The former method allowed consideration of the reflectance off the back surface of the wafer, which occurs typically at wavelengths above 1000 nm due to the transparency of silicon at these wavelengths. However, this method does not take into consideration the absorption occurring in the silicon nitride, which is negligible at low refractive indexes but quite significant when the refractive index increases above 2.1. For high-index silicon nitride films, the latter method is more accurate as it considers both reflectance and absorbance in the film to calculate the transmittance into the Si wafer. Both methods reach similar values for film thickness and refractive index for optimised single layer anti-reflective coatings, due to the negligible absorption occurring in these films. For double layer coatings, though, the reflectance based simulations overestimated the optimum refractive index for the bottom layer, which would have lead to excessive absorption if applied to real anti-reflective coatings. The experimental study on physical properties for silicon nitride films deposited under varying conditions concentrated on the estimation of properties important for its applications, such as optical properties, passivation

  13. Epitaxial growth of Si1−xGex alloys and Ge on Si(100) by electron-cyclotron-resonance Ar plasma chemical vapor deposition without substrate heating

    International Nuclear Information System (INIS)

    Ueno, Naofumi; Sakuraba, Masao; Murota, Junichi; Sato, Shigeo

    2014-01-01

    By using electron-cyclotron-resonance (ECR) Ar-plasma chemical vapor deposition (CVD) without substrate heating, the epitaxial growth process of Si 1−x Ge x alloy and Ge films deposited directly on dilute-HF-treated Si(100) was investigated. From the reflection high energy electron diffraction patterns of the deposited Si 1−x Ge x alloy (x = 0.50, 0.75) and Ge films on Si(100), it is confirmed that epitaxial growth can be realized without substrate heating, and that crystallinity degradation at larger film thickness is observed. The X-ray diffraction peak of the epitaxial films reveals the existence of large compressive strain, which is induced by lattice matching with the Si(100) substrate at smaller film thicknesses, as well as strain relaxation behavior at larger film thicknesses. The Ge fraction of Si 1−x Ge x thin film is in good agreement with the normalized GeH 4 partial pressure. The Si 1−x Ge x deposition rate increases with an increase of GeH 4 partial pressure. The GeH 4 partial pressure dependence of partial deposition rates [(Si or Ge fraction) × (Si 1−x Ge x thickness) / (deposition time)] shows that the Si partial deposition rate is slightly enhanced by the existence of Ge. From these results, it is proposed that the ECR-plasma CVD process can be utilized for Ge fraction control in highly-strained heterostructure formation of group IV semiconductors. - Highlights: • Si 1−x Ge x alloy and Ge were epitaxially grown on Si(100) without substrate heating. • Large strain and its relaxation behavior can be observed by X-ray diffraction. • Ge fraction of Si 1−x Ge x is equal to normalized GeH 4 partial pressure. • Si partial deposition rate is slightly enhanced by existence of Ge

  14. Determination of trace cadmium in rice by liquid spray dielectric barrier discharge induced plasma - chemical vapor generation coupled with atomic fluorescence spectrometry

    Science.gov (United States)

    Liu, Xing; Zhu, Zhenli; Bao, Zhengyu; Zheng, Hongtao; Hu, Shenghong

    2018-03-01

    Cadmium contamination in rice has become an increasing concern in many countries including China. A simple, cost-effective, and highly sensitive method was developed for the determination of trace cadmium in rice samples based on a new high-efficient liquid spray dielectric barrier discharge induced plasma (LSDBD) vapor generation coupled with atomic fluorescence spectrometry (AFS). The analytical procedure involves the efficient formation of Cd volatile species by LSDBD plasma induced chemical processes without the use of any reducing reagents (Na/KBH4 in conventional hydride generation). The effects of the addition of organic substances, different discharge parameters such as discharge voltage and discharge gap, as well as the foreign ion interferences were investigated. Under optimized conditions, a detection limit of 0.01 μg L- 1 and a precision of 0.8% (RSD, n = 5, 1 μg L- 1 Cd) was readily achieved. The calibration curve was linear in the range between 0.1 and 10 μg L- 1, with a correlation coefficient of R2 = 0.9995. Compared with the conventional acid-BH4- vapor generation, the proposed method not only eliminates the use of unstable and expensive reagents, but also offers high tolerance for coexisting ions, which is well suited to the direct analysis of environmental samples. The validation of the proposed method was demonstrated by the analysis of Cd in reference material of rice (GBW080684). It was also successfully applied to the determination of trace cadmium in locally collected 11 rice samples, and the obtained Cd concentrations are ranged from 7.2 to 517.7 μg kg- 1.

  15. Electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of trace amount of lanthanides and yttrium in soil with polytetrafluroethylene emulsion as a chemical modifier

    International Nuclear Information System (INIS)

    He Man; Hu, Bin; Jiang Zucheng

    2005-01-01

    A method of electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace lanthanides and yttrium in soil samples with a polytetrafluorethylene (PTFE) emulsion as chemical modifier to promote the vaporization of the analytes from the graphite furnace was developed in this paper. The analytical characteristics, spectral interference and matrix effect of the analytical method were evaluated and critically compared with those of pneumatic nebulization inductively coupled plasma mass spectrometry (PN-ICP-MS). Under the optimized operation conditions, the relative detection limits of lanthanides (La-Lu) and yttrium for ETV-ICP-MS and PN-ICP-MS were 0.4-20 ng l -1 and 1.0-21 ng l -1 , respectively, the absolute detection limits for ETV-ICP-MS were 4-200 fg, which were improved by 1-2 orders of magnitude compared with PN-ICP-MS. While the analytical precision of ETV-ICP-MS is worse than that of PN-ICP-MS, with the R.S.D.s (%) of 4.1-10% for the former and 2.9-7.8% for the latter. Regarding to the matrix effect, both conventional method and stepwise dilution method were employed to observe the effect of matrix and the very similar results were obtained. It was found that the highest tolerance concentration of the matrix is 1000 mg l -1 and 800 mg l -1 for ETV-ICP-MS and PN-ICP-MS, respectively. To assess the accuracy, the proposed method was applied to the determination of trace lanthanides and yttrium in three different soil standard reference materials and one soil sample, and the determined values are in good agreement with the certified values or reference values

  16. High-speed three-dimensional plasma temperature determination of axially symmetric free-burning arcs

    International Nuclear Information System (INIS)

    Bachmann, B; Ekkert, K; Bachmann, J-P; Marques, J-L; Schein, J; Kozakov, R; Gött, G; Schöpp, H; Uhrlandt, D

    2013-01-01

    In this paper we introduce an experimental technique that allows for high-speed, three-dimensional determination of electron density and temperature in axially symmetric free-burning arcs. Optical filters with narrow spectral bands of 487.5–488.5 nm and 689–699 nm are utilized to gain two-dimensional spectral information of a free-burning argon tungsten inert gas arc. A setup of mirrors allows one to image identical arc sections of the two spectral bands onto a single camera chip. Two-different Abel inversion algorithms have been developed to reconstruct the original radial distribution of emission coefficients detected with each spectral window and to confirm the results. With the assumption of local thermodynamic equilibrium we calculate emission coefficients as a function of temperature by application of the Saha equation, the ideal gas law, the quasineutral gas condition and the NIST compilation of spectral lines. Ratios of calculated emission coefficients are compared with measured ones yielding local plasma temperatures. In the case of axial symmetry the three-dimensional plasma temperature distributions have been determined at dc currents of 100, 125, 150 and 200 A yielding temperatures up to 20000 K in the hot cathode region. These measurements have been validated by four different techniques utilizing a high-resolution spectrometer at different positions in the plasma. Plasma temperatures show good agreement throughout the different methods. Additionally spatially resolved transient plasma temperatures have been measured of a dc pulsed process employing a high-speed frame rate of 33000 frames per second showing the modulation of the arc isothermals with time and providing information about the sensitivity of the experimental approach. (paper)

  17. High density plasma productions by hydrogen storage electrode in the Tohoku University Heliac

    International Nuclear Information System (INIS)

    Utoh, H.; Takahashi, H.; Tanaka, Y.; Takenaga, M.; Ogawa, M.; Shinde, J.; Iwazaki, K.; Shinto, K.; Kitajima, S.; Sasao, M.; Nishimura, K.; Inagaki, S.

    2005-01-01

    In the Tohoku University Heliac (TU-Heliac), the influence of a radial electric field on improved modes has been investigated by an electrode biasing. In both positive and negative biasing experiments by the stainless steel (SUS) electrode (cold-electron or ion collection), the improvement of plasma confinement was clearly observed. Furthermore, by negative biasing with a hot cathode (electron injection), the radial electric fields can be actively controlled as a consequence of the control of the electrode current I E . By using the electrode made of a hydrogen storage metal, for example Titanium (Ti) or Vanadium (V), the following possibility can be expected: (1) ions accelerated from the positive biased electrode allow the simulation for the orbit loss of high-energy particles, (2) the electrons/neutral- particles injected from the negative biased electrode provide the production of the high- density plasma, if hydrogen are successfully stored in the electrode. In this present work, several methods were tried as the treatment for hydrogen storage. In the case of the Ti electrode biased positively after the treatment, the improvement of plasma confinement was observed in He plasma, which were same as the experimental results of the SUS electrode. However, in the electron density profiles inside the electrode position there was difference between the biased plasma by the Ti electrode and that by the SUS electrode. In some of Ar discharges biased negatively with the Ti electrode after the treatment, the electron density and the line intensity of H α increased about 10 times of those before biasing. This phenomenon has not been observed in the Ar plasma biased by the SUS electrode. This result suggested that the Ti electrode injected electrons/neutral-hydrogen into the plasma. This high-density plasma productions were observed only 1 ∼ 3 times in the one treatment for hydrogen storage. By using a Vanadium (V) electrode, productions of the high-density plasma

  18. Effect of nickel oxide seed layers on annealed-amorphous titanium oxide thin films prepared using plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Wu, Cheng-Yang; Hong, Shao-Chyang; Hwang, Fu-Tsai; Lai, Li-Wen; Lin, Tan-Wei; Liu, Day-Shan

    2011-01-01

    The effect of a nickel oxide (NiO x ) seed layer on the crystallization and photocatalytic activity of the sequentially plasma-enhanced chemical vapor deposited amorphous titanium oxide (TiO x ) thin film processed by a post-annealing process was investigated. The evolution of the crystalline structures, chemical bond configurations, and surface/cross-sectional morphologies of the annealed TiO x films, with and without a NiO x seed layer, was examined using X-ray diffractometer, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscope measurements. Thermo- and photo-induced hydrophilicity was determined by measuring the contact angle of water droplet. Photocatalytic activity after UV light irradiation was evaluated from the decolorization of a methylene blue solution. The crystallization temperature of the TiO x film, deposited on a NiO x seed layer, was found to be lower than that of a pure TiO x film, further improving the thermo- and photo-induced surface super-hydrophilicity. The TiO x film deposited onto the NiO x seed layer, resulting in significant cluster boundaries, showed a rough surface morphology and proved to alleviate the anatase crystal growth by increasing the post-annealing temperature, which yielded a more active surface area and prohibited the recombination of photogenerated electrons and holes. The photocatalytic activity of the NiO x /TiO x system with such a textured surface therefore was enhanced and optimized through an adequate post-annealing process.

  19. Silicon nitride films fabricated by a plasma-enhanced chemical vapor deposition method for coatings of the laser interferometer gravitational wave detector

    Science.gov (United States)

    Pan, Huang-Wei; Kuo, Ling-Chi; Huang, Shu-Yu; Wu, Meng-Yun; Juang, Yu-Hang; Lee, Chia-Wei; Chen, Hsin-Chieh; Wen, Ting Ting; Chao, Shiuh

    2018-01-01

    Silicon is a potential substrate material for the large-areal-size mirrors of the next-generation laser interferometer gravitational wave detector operated in cryogenics. Silicon nitride thin films uniformly deposited by a chemical vapor deposition method on large-size silicon wafers is a common practice in the silicon integrated circuit industry. We used plasma-enhanced chemical vapor deposition to deposit silicon nitride films on silicon and studied the physical properties of the films that are pertinent to application of mirror coatings for laser interferometer gravitational wave detectors. We measured and analyzed the structure, optical properties, stress, Young's modulus, and mechanical loss of the films, at both room and cryogenic temperatures. Optical extinction coefficients of the films were in the 10-5 range at 1550-nm wavelength. Room-temperature mechanical loss of the films varied in the range from low 10-4 to low 10-5 within the frequency range of interest. The existence of a cryogenic mechanical loss peak depended on the composition of the films. We measured the bond concentrations of N - H , Si - H , Si - N , and Si - Si bonds in the films and analyzed the correlations between bond concentrations and cryogenic mechanical losses. We proposed three possible two-level systems associated with the N - H , Si - H , and Si - N bonds in the film. We inferred that the dominant source of the cryogenic mechanical loss for the silicon nitride films is the two-level system of exchanging position between a H+ and electron lone pair associated with the N - H bond. Under our deposition conditions, superior properties in terms of high refractive index with a large adjustable range, low optical absorption, and low mechanical loss were achieved for films with lower nitrogen content and lower N - H bond concentration. Possible pairing of the silicon nitride films with other materials in the quarter-wave stack is discussed.

  20. Effect of nickel oxide seed layers on annealed-amorphous titanium oxide thin films prepared using plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Cheng-Yang; Hong, Shao-Chyang [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, 63201, Taiwan (China); Hwang, Fu-Tsai [Department of Electro-Optical Engineering, National United University, Miao-Li, 36003, Taiwan (China); Lai, Li-Wen [ITRI South, Industrial Technology Research Institute, Liujia, Tainan, 73445, Taiwan (China); Lin, Tan-Wei [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, 63201, Taiwan (China); Liu, Day-Shan, E-mail: dsliu@sunws.nfu.edu.tw [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, 63201, Taiwan (China)

    2011-10-31

    The effect of a nickel oxide (NiO{sub x}) seed layer on the crystallization and photocatalytic activity of the sequentially plasma-enhanced chemical vapor deposited amorphous titanium oxide (TiO{sub x}) thin film processed by a post-annealing process was investigated. The evolution of the crystalline structures, chemical bond configurations, and surface/cross-sectional morphologies of the annealed TiO{sub x} films, with and without a NiO{sub x} seed layer, was examined using X-ray diffractometer, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscope measurements. Thermo- and photo-induced hydrophilicity was determined by measuring the contact angle of water droplet. Photocatalytic activity after UV light irradiation was evaluated from the decolorization of a methylene blue solution. The crystallization temperature of the TiO{sub x} film, deposited on a NiO{sub x} seed layer, was found to be lower than that of a pure TiO{sub x} film, further improving the thermo- and photo-induced surface super-hydrophilicity. The TiO{sub x} film deposited onto the NiO{sub x} seed layer, resulting in significant cluster boundaries, showed a rough surface morphology and proved to alleviate the anatase crystal growth by increasing the post-annealing temperature, which yielded a more active surface area and prohibited the recombination of photogenerated electrons and holes. The photocatalytic activity of the NiO{sub x}/TiO{sub x} system with such a textured surface therefore was enhanced and optimized through an adequate post-annealing process.

  1. Formation and characterization of the MgO protecting layer deposited by plasma-enhanced metal-organic chemical-vapor deposition

    CERN Document Server

    Kang, M S; Byun, J C; Kim, D S; Choi, C K; Lee, J Y; Kim, K H

    1999-01-01

    MgO films were prepared on Si(100) and soda-lime glass substrates by using plasma-enhanced metal-organic chemical-vapor deposition. Various ratios of the O sub 2 /CH sub 3 MgO sup t Bu gas mixture and various gas flow rates were tested for the film fabrications. Highly (100)-oriented MgO films with good crystallinity were obtained with a 10 sccm CH sub 3 MgO sup t Bu flow without an O sub 2 gas flow. About 5 % carbon was contained in all the MgO films. The refractive index and the secondary electron emission coefficient for the best quality film were 1.43 and 0.45, respectively. The sputtering rate was about 0.2 nm/min for 10 sup 1 sup 1 cm sup - sup 3 Ar sup + ion density. Annealing at 500 .deg. C in an Ar ambient promoted the grain size without inducing a phase transition.

  2. Effects of thermal annealing on the structural, mechanical, and tribological properties of hard fluorinated carbon films deposited by plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Maia da Costa, M. E. H.; Baumvol, I. J. R.; Radke, C.; Jacobsohn, L. G.; Zamora, R. R. M.; Freire, F. L.

    2004-11-01

    Hard amorphous fluorinated carbon films (a-C:F) deposited by plasma enhanced chemical vapor deposition were annealed in vacuum for 30 min in the temperature range of 200-600 °C. The structural and compositional modifications were followed by several analytical techniques: Rutherford backscattering spectrometry (RBS), elastic recoil detection analysis (ERDA), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Nanoidentation measurements and lateral force microscopy experiments were carried out in order to provide the film hardness and the friction coefficient, respectively. The internal stress and contact angle were also measured. RBS, ERDA, and XPS results indicate that both fluorine and hydrogen losses occur for annealing temperatures higher than 300 °C. Raman spectroscopy shows a progressive graphitization upon annealing, while the surface became slightly more hydrophobic as revealed by the increase of the contact angle. Following the surface wettability reduction, a decrease of the friction coefficient was observed. These results highlight the influence of the capillary condensation on the nanoscale friction. The film hardness and the internal stress are constant up to 300 °C and decrease for higher annealing temperatures, showing a direct correlation with the atomic density of the films. Since the thickness variation is negligible, the mass loss upon thermal treatment results in amorphous structures with a lower degree of cross-linking, explaining the deterioration of the mechanical properties of the a-C:F films.

  3. Identification of the Chemical Constituents in Simiao Wan and Rat Plasma after Oral Administration by GC-MS and LC-MS

    Directory of Open Access Journals (Sweden)

    Yunshuang Fan

    2017-01-01

    Full Text Available Simiao Wan (SMW, an important multiherbal formula used in traditional Chinese medicine, is extensively used to treat rheumatoid arthritis. However, the knowledge of the bioactive components of SMW remains unclear. Thus, gas chromatography–mass spectrometry (GC-MS and liquid chromatography–mass spectrometry (LC-MS were used to analyze the chemical constituents of volatile and nonvolatile extracts of SMW, as well as its absorbed components in rat plasma after oral SMW administration. Identification of several compounds was enabled by comparison of retention times, MS spectra, and MS/MS spectral data with the standard substance and reference materials reported in the literature. In the volatile extracts, GC-MS identified 26 compounds in vitro, three of which observed in blood by GC-MS. In the nonvolatile extracts, LC-MS identified 49 compounds in SMW; 18 compounds containing 7 prototype compounds, 5 metabolites, and 6 unknown compounds were absorbed by blood. The proposed GC-MS and LC-MS method was appropriate not only for the rapid screening and identification of multiple components of an SMW extract but also for screening its bioactive constituents in vivo. The proposed method could be a promising tool for the quality control of other Chinese herbal medicines.

  4. Thermal expansion coefficient and thermomechanical properties of SiN(x) thin films prepared by plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Tien, Chuen-Lin; Lin, Tsai-Wei

    2012-10-20

    We present a new method based on fast Fourier transform (FFT) for evaluating the thermal expansion coefficient and thermomechanical properties of thin films. The silicon nitride thin films deposited on Corning glass and Si wafers were prepared by plasma-enhanced chemical vapor deposition in this study. The anisotropic residual stress and thermomechanical properties of silicon nitride thin films were studied. Residual stresses in thin films were measured by a modified Michelson interferometer associated with the FFT method under different heating temperatures. We found that the average residual-stress value increases when the temperature increases from room temperature to 100°C. Increased substrate temperature causes the residual stress in SiN(x) film deposited on Si wafers to be more compressive, but the residual stress in SiN(x) film on Corning glass becomes more tensile. The residual-stress versus substrate-temperature relation is a linear correlation after heating. A double substrate technique is used to determine the thermal expansion coefficients of the thin films. The experimental results show that the thermal expansion coefficient of the silicon nitride thin films is 3.27×10(-6)°C(-1). The biaxial modulus is 1125 GPa for SiN(x) film.

  5. Heteroepitaxial growth of Ba1 - xSrxTiO3/YBa2Cu3O7 - x by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Chern, C. S.; Liang, S.; Shi, Z. Q.; Yoon, S.; Safari, A.; Lu, P.; Kear, B. H.; Goodreau, B. H.; Marks, T. J.; Hou, S. Y.

    1994-06-01

    Epitaxial Ba1-xSrxTiO3(BST)/YBa2Cu3O7-x heterostructures with superior electrical and dielectric properties have been fabricated by plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD). Data of x-ray diffraction and high resolution transmission electron microscopy showed that oriented Ba1-xSrxTiO3 layers were epitaxially deposited on epitaxial (001) YBa2Cu3O7-x layers. The leakage current density through the Ba1-xSrxTiO3 films was about 10-7 A/cm2 at 2 V (about 2×105 V/cm) operation. Moreover, the results of capacitance-temperature measurements showed that the PE-MOCVD Ba1-xSrxTiO3 films had Curie temperatures of about 30 °C and a peak dielectric constant of 600 at zero bias voltage. The Rutherford backscattering spectrometry and x-ray diffraction results showed that the BST film composition was controlled between Ba0.75Sr0.25TiO3 and Ba0.8Sr0.2TiO3. The structural and electrical properties of the Ba1-xSrxTiO3/YBa2Cu3O7-x heterostructure indicated that conductive oxide materials with close lattice to Ba1-xSrxTiO3 can be good candidates for the bottom electrode.

  6. Growth, microstructure, and field-emission properties of synthesized diamond film on adamantane-coated silicon substrate by microwave plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Tiwari, Rajanish N.; Chang Li

    2010-01-01

    Diamond nucleation on unscratched Si surface is great importance for its growth, and detailed understanding of this process is therefore desired for many applications. The pretreatment of the substrate surface may influence the initial growth period. In this study, diamond films have been synthesized on adamantane-coated crystalline silicon {100} substrate by microwave plasma chemical vapor deposition from a gaseous mixture of methane and hydrogen gases without the application of a bias voltage to the substrates. Prior to adamantane coating, the Si substrates were not pretreated such as abraded/scratched. The substrate temperature was ∼530 deg. C during diamond deposition. The deposited films are characterized by scanning electron microscopy, Raman spectrometry, x-ray diffraction, and x-ray photoelectron spectroscopy. These measurements provide definitive evidence for high-crystalline quality diamond film, which is synthesized on a SiC rather than clean Si substrate. Characterization through atomic force microscope allows establishing fine quality criteria of the film according to the grain size of nanodiamond along with SiC. The diamond films exhibit a low-threshold (55 V/μm) and high current-density (1.6 mA/cm 2 ) field-emission (FE) display. The possible mechanism of formation of diamond films and their FE properties have been demonstrated.

  7. Characterization of Pb(Zr, Ti)O3 thin films fabricated by plasma enhanced chemical vapor deposition on Ir-based electrodes

    International Nuclear Information System (INIS)

    Lee, Hee-Chul; Lee, Won-Jong

    2002-01-01

    Structural and electrical characteristics of Pb(Zr, Ti)O 3 (PZT) ferroelectric thin films deposited on various Ir-based electrodes (Ir, IrO 2 , and Pt/IrO 2 ) using electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. On the Ir electrode, stoichiometric PZT films with pure perovskite phase could be obtained over a very wide range of processing conditions. However, PZT films prepared on the IrO 2 electrode contain a large amount of PbO x phases and exhibited high Pb-excess composition. The deposition characteristics were dependent on the behavior of PbO molecules on the electrode surface. The PZT thin film capacitors prepared on the Ir bottom electrode showed different electrical properties depending on top electrode materials. The PZT capacitors with Ir, IrO 2 , and Pt top electrodes showed good leakage current characteristics, whereas those with the Ru top electrode showed a very high leakage current density. The PZT capacitor exhibited the best fatigue endurance with an IrO 2 top electrode. An Ir top electrode provided better fatigue endurance than a Pt top electrode. The PZT capacitor with an Ir-based electrode is thought to be attractive for the application to ferroelectric random access memory devices because of its wide processing window for a high-quality ferroelectric film and good polarization, fatigue, and leakage current characteristics

  8. Impact of hydrogen dilution on optical properties of intrinsic hydrogenated amorphous silicon films prepared by high density plasma chemical vapor deposition for solar cell applications

    Science.gov (United States)

    Chen, Huai-Yi; Lee, Yao-Jen; Chang, Chien-Pin; Koo, Horng-Show; Lai, Chiung-Hui

    2013-01-01

    P-i-n single-junction hydrogenated amorphous silicon (a-Si:H) thin film solar cells were successfully fabricated in this study on a glass substrate by high density plasma chemical vapor deposition (HDP-CVD) at low power of 50 W, low temperature of 200°C and various hydrogen dilution ratios (R). The open circuit voltage (Voc ), short circuit current density (Jsc ), fill factor (FF) and conversion efficiency (η) of the solar cell as well as the refractive index (n) and absorption coefficient (α) of the i-layer at 600 nm wavelength rise with increasing R until an abrupt drop at high hydrogen dilution, i.e. R > 0.95. However, the optical energy bandgap (Eg ) of the i-layer decreases with the R increase. Voc and α are inversely correlated with Eg . The hydrogen content affects the i-layer and p/i interface quality of the a-Si:H thin film solar cell with an optimal value of R = 0.95, which corresponds to solar cell conversion efficiency of 3.85%. The proposed a-Si:H thin film solar cell is expected to be improved in performance.

  9. Nanocrystalline-Si-dot multi-layers fabrication by chemical vapor deposition with H-plasma surface treatment and evaluation of structure and quantum confinement effects

    Directory of Open Access Journals (Sweden)

    Daisuke Kosemura

    2014-01-01

    Full Text Available 100-nm-thick nanocrystalline silicon (nano-Si-dot multi-layers on a Si substrate were fabricated by the sequential repetition of H-plasma surface treatment, chemical vapor deposition, and surface oxidation, for over 120 times. The diameter of the nano-Si dots was 5–6 nm, as confirmed by both the transmission electron microscopy and X-ray diffraction analysis. The annealing process was important to improve the crystallinity of the nano-Si dot. We investigated quantum confinement effects by Raman spectroscopy and photoluminescence (PL measurements. Based on the experimental results, we simulated the Raman spectrum using a phenomenological model. Consequently, the strain induced in the nano-Si dots was estimated by comparing the experimental and simulated results. Taking the estimated strain value into consideration, the band gap modulation was measured, and the diameter of the nano-Si dots was calculated to be 5.6 nm by using PL. The relaxation of the q ∼ 0 selection rule model for the nano-Si dots is believed to be important to explain both the phenomena of peak broadening on the low-wavenumber side observed in Raman spectra and the blue shift observed in PL measurements.

  10. Effect of the hydrogen flow rate on the structural and optical properties of hydrogenated amorphous silicon thin films prepared by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ben Amor, Sana; Dimassi, Wissem; Ali Tebai, Mohamed; Ezzaouia, Hatem [Photovoltaic Laboratory Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia)

    2012-10-15

    Hydrogenated amorphous silicon (a-Si:H) thin films were deposited from pure silane (SiH{sub 4}) and hydrogen (H{sub 2}) gas mixture by plasma enhanced chemical vapor deposition (PECVD) method at low temperature (400 C) using high rf power (60 W). The structural and optical properties of these films are systematically investigated as a function of the flow rate of hydrogen (F{sub H2}).The surface morphology is analyzed by atomic force microscopy (AFM). The characterization of these films with low angle X-ray diffraction revealed that the crystallite size in the films tends to decrease with increase in (F{sub H2}). The Fourier transform infrared (FTIR) spectroscopic analysis showed that at low values of (F{sub H2}),the hydrogen bonding in Si:H films shifts from di-hydrogen (Si-H{sub 2}) and (Si-H{sub 2})n complexes to the mono-hydrogen (Si-H) bonding configuration. Finally, for these optimized conditions, the deposition rate decreases with increasing (F{sub H2}). (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. New fabrication technique using side-wall-type plasma-enhanced chemical-vapor deposition for a floating gate memory with a Si nanodot

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Kazunori; Punchaipetch, Prakaipetch; Yano, Hiroshi; Hatayama, Tomoaki; Uraoka, Yukiharu; Fuyuki, Takashi [Nara Institute of Science and Techonology, Ikoma, Nara (Japan); Tomyo, Atsushi; Takahashi, Eiji; Hayashi, Tsukasa; Ogata, Kiyoshi [Nissin Electric Co., Ltd., Kyoto (Japan)

    2006-08-15

    We have used side-wall-type plasma-enhanced chemical-vapor deposition (PECVD)to fabricate a floating gate memory using a Si nano-crystal dot on thermal SiO{sub 2} at a low temperature of 430 .deg. C. Atomic and radical hydrogen plays an important role in the low-temperature formation of the dot. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) analyses revealed that the average dot size and density were approximately 5 nm and 8.5 X 10{sup 11} cm{sup -2}, respectively. The electronic properties were investigated with metal-oxide-semiconductor-field-effect transistors (MOSFETs) by embedding the nanocrystal dots into SiO{sub 2} fabricated using CVD. Electron charging and discharging were clearly confirmed at room temperature by the transient behavior of the capacitance and the transfer curve. The number of electrons confined in a single dot was approximately one. Furthermore, we evaluated the electronic behavior by varying the bias condition or the operating temperature. The critical charge density could be confirmed to be independent of the injection condition.

  12. Nonequilibrium phenomena and determination of plasma parameters in the hot core of the cathode region in free-burning arc discharges

    International Nuclear Information System (INIS)

    Kuehn, Gerrit; Kock, Manfred

    2007-01-01

    We present spectroscopic measurements of plasma parameters (electron density n e , electron temperature T e , gas temperature T g , underpopulation factor b) in the hot-core region in front of the cathode of a low-current, free-burning arc discharge in argon under atmospheric pressure. The discharge is operated in the hot-core mode, creating a hot cathode region with plasma parameters similar to high-current arcs in spite of the fact that we use comparatively low currents (less than 20 A). We use continuum emission and (optically thin) line emission to determine n e and T e . We apply relaxation measurements based on a power-interruption technique to investigate deviations from local thermodynamic equilibrium (LTE). These measurements let us determine the gas temperature T g . All measurements are performed side-on with charge-coupled-device cameras as detectors, so that all measured plasma parameters are spatially resolved after an Abel inversion. This yields the first ever spatially resolved observation of the non-LTE phenomena of the hot core in the near-cathode region of free-burning arcs. The results only partly coincide with previously published predictions and measurements in the literature

  13. The influence of surface microstructure and chemical composition on corrosion behaviour in fuel-grade bio-ethanol of low-alloy steel modified by plasma nitro-carburizing and post-oxidizing

    Science.gov (United States)

    Boniatti, Rosiana; Bandeira, Aline L.; Crespi, Ângela E.; Aguzzoli, Cesar; Baumvol, Israel J. R.; Figueroa, Carlos A.

    2013-09-01

    The interaction of bio-ethanol on steel surfaces modified by plasma-assisted diffusion technologies is studied for the first time. The influence of surface microstructure and chemical composition on corrosion behaviour of AISI 4140 low-alloy steel in fuel-grade bio-ethanol was investigated. The steel surfaces were modified by plasma nitro-carburizing followed plasma oxidizing. X-ray diffraction, scanning electron microscopy, optical microscopy, X-ray dispersive spectroscopy, and glow-discharge optical emission spectroscopy were used to characterize the modified surface before and after immersion tests in bio-ethanol up to 77 days. The main corrosion mechanism is pit formation. The pit density and pit size were measured in order to quantify the corrosion resistance which was found to depend more strongly on microstructure and morphology of the oxide layer than on its thickness. The best corrosion protection was observed for samples post-oxidized at 480 °C and 90 min.

  14. The influence of surface microstructure and chemical composition on corrosion behaviour in fuel-grade bio-ethanol of low-alloy steel modified by plasma nitro-carburizing and post-oxidizing

    International Nuclear Information System (INIS)

    Boniatti, Rosiana; Bandeira, Aline L.; Crespi, Ângela E.; Aguzzoli, Cesar; Baumvol, Israel J.R.; Figueroa, Carlos A.

    2013-01-01

    The interaction of bio-ethanol on steel surfaces modified by plasma-assisted diffusion technologies is studied for the first time. The influence of surface microstructure and chemical composition on corrosion behaviour of AISI 4140 low-alloy steel in fuel-grade bio-ethanol was investigated. The steel surfaces were modified by plasma nitro-carburizing followed plasma oxidizing. X-ray diffraction, scanning electron microscopy, optical microscopy, X-ray dispersive spectroscopy, and glow-discharge optical emission spectroscopy were used to characterize the modified surface before and after immersion tests in bio-ethanol up to 77 days. The main corrosion mechanism is pit formation. The pit density and pit size were measured in order to quantify the corrosion resistance which was found to depend more strongly on microstructure and morphology of the oxide layer than on its thickness. The best corrosion protection was observed for samples post-oxidized at 480 °C and 90 min.

  15. Cold plasmas

    International Nuclear Information System (INIS)

    Franz, G.

    1990-01-01

    This textbook discusses the following topics: Phenomenological description of a direct current glow discharge; the plasma (temperature distribution and measurement, potential variation, electron energy distribution function, charge neutralization, wall potentials, plasma oscillations); Production of charge carriers (ions, electrons, ionization in the cathode zone, negative glowing zone, Faraday dark space, positive column, anode zone, hollow cathode discharges); RF-discharges (charge carrier production, RF-Shields, scattering mechanisms); Sputtering (ion-surface interaction, kinetics, sputtering yield and energy distribution, systems and conditions, film formation and stresses, contamination, bias techniques, multicomponent film deposition, cohesion, magnetrons, triode systems, plasma enhanced chemical vapor deposition); Dry etching (sputter etching, reactive etching, topography, process control, quantitative investigations); Etching mechanisms (etching of Si and SiO 2 with CF 4 , of III/V-compound-semiconductors, combination of isotrope and anisotrope etching methods, surface cleaning); ion beam systems (applications, etching); Dyclotron-resonance-systems (electron cyclotron resonance systems, whistler-sources and 'resonant inductive plasma etching'); Appendix (electron energy distribution functions, Bohm's transition zone, plasma oscillations, scattering cross sections and mean free path, metastable states, Child-Langmuir-Schottky equation, loss mechanisms, charge carrier distribution in the positive column, breakdown at high frequencies, motion in a magnetic field, skin depth of an electric field for a HF-discharge, whistler waves, dispersion relations for plane wave propagation). (orig.) With 138 figs

  16. Modeling of Plasma-Induced Ignition and Combustion

    National Research Council Canada - National Science Library

    Boyd, Iain D; Keidar, Michael

    2008-01-01

    .... Phenomena that must be considered in an electrothermal chemical gun model include the initial capillary plasma properties, the plasma-air interaction, plasma sheath effects, and the plasma-propellant interaction itself...

  17. Gas diffusion ultrabarriers on polymer substrates using Al2O3 atomic layer deposition and SiN plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Carcia, P. F.; McLean, R. S.; Groner, M. D.; Dameron, A. A.; George, S. M.

    2009-01-01

    Thin films grown by Al 2 O 3 atomic layer deposition (ALD) and SiN plasma-enhanced chemical vapor deposition (PECVD) have been tested as gas diffusion barriers either individually or as bilayers on polymer substrates. Single films of Al 2 O 3 ALD with thicknesses of ≥10 nm had a water vapor transmission rate (WVTR) of ≤5x10 -5 g/m 2 day at 38 deg. C/85% relative humidity (RH), as measured by the Ca test. This WVTR value was limited by H 2 O permeability through the epoxy seal, as determined by the Ca test for the glass lid control. In comparison, SiN PECVD films with a thickness of 100 nm had a WVTR of ∼7x10 -3 g/m 2 day at 38 deg. C/85% RH. Significant improvements resulted when the SiN PECVD film was coated with an Al 2 O 3 ALD film. An Al 2 O 3 ALD film with a thickness of only 5 nm on a SiN PECVD film with a thickness of 100 nm reduced the WVTR from ∼7x10 -3 to ≤5x10 -5 g/m 2 day at 38 deg. C/85% RH. The reduction in the permeability for Al 2 O 3 ALD on the SiN PECVD films was attributed to either Al 2 O 3 ALD sealing defects in the SiN PECVD film or improved nucleation of Al 2 O 3 ALD on SiN.

  18. Sampling strategy and analysis of trace element concentrations by inductively coupled plasma mass spectrometry on medieval human bones--the concept of chemical life history.

    Science.gov (United States)

    Skytte, Lilian; Rasmussen, Kaare Lund

    2013-07-30

    Medieval human bones have the potential to reveal diet, mobility and treatment of diseases in the past. During the last two decades trace element chemistry has been used extensively in archaeometric investigations revealing such data. Many studies have reported the trace element inventory in only one sample from each skeleton - usually from the femur or a tooth. It cannot a priori be assumed that all bones or teeth in a skeleton will have the same trace element concentrations. Six different bone and teeth samples from each individual were carefully decontaminated by mechanical means. Following dissolution of ca. 20 mg sample in nitric acid and hydrogen peroxide the assays were performed using inductively coupled plasma mass spectrometry (ICPMS) with quadropole detection. We describe the precise sampling technique as well as the analytical methods and parameters used for the ICPMS analysis. The places of sampling in the human skeleton did exhibit varying trace element concentrations. Although the samples are contaminated by Fe, Mn and Al from the surrounding soil where the bones have been residing for more than 500 years, other trace elements are intact within the bones. It is shown that the elemental ratios Sr/Ca and Ba/Ca can be used as indicators of provenance. The differences in trace element concentrations can be interpreted as indications of varying diet and provenance as a function of time in the life of the individual - a concept which can be termed chemical life history. A few examples of the results of such analyses are shown, which contains information about provenance and diagenesis. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Epitaxial growth of SrTiO3/YBa2Cu3O7 - x heterostructures by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Liang, S.; Chern, C. S.; Shi, Z. Q.; Lu, P.; Safari, A.; Lu, Y.; Kear, B. H.; Hou, S. Y.

    1994-06-01

    We report heteroepitaxial growth of SrTiO3 on YBa2Cu3O7-x/LaAlO3 substrates by plasma-enhanced metalorganic chemical vapor deposition. X-ray diffraction results indicated that SrTiO3 films were epitaxially grown on a (001) YBa2Cu3O7-x surface with [100] orientation perpendicular to the surface. The film composition, with Sr/Ti molar ratio in the range of 0.9 to 1.1, was determined by Rutherford backscattering spectrometry and energy dispersive spectroscopy. The thickness of the SrTiO3 films is 0.1-0.2 μm. The epitaxial growth was further evidenced by high-resolution transmission electron microscopy and selected area diffraction. Atomically abrupt SrTiO3/YBa2Cu3O7-x interface and epitaxial growth with [100]SrTiO3∥[001]YBa2Cu3O7-x were observed in this study. The superconducting transition temperature of the bottom YBa2Cu3O7-x layer, as measured by ac susceptometer, did not significantly degrade after the growth of overlayer SrTiO3. The capacitance-voltage measurements showed that the dielectric constant of the SrTiO3 films was as high as 315 at a signal frequency of 100 KHz. The leakage current density through the SrTiO3 films is about 1×10-6 A/cm2 at 2-V operation. Data analysis on the current-voltage characteristic indicated that the conduction process is related to bulk-limited Poole-Frenkel emission.

  20. The study and the realization of radiation detectors made from polycrystalline diamond films grown by microwave plasma enhanced chemical vapour deposition technique

    International Nuclear Information System (INIS)

    Jany, Ch.

    1998-01-01

    The aim of this work was to develop radiation detectors made from polycrystalline diamond films grown by microwave plasma enhanced chemical vapour deposition technique. The influence of surface treatments, contact technology and diamond growth parameters on the diamond detectors characteristics was investigated in order to optimise the detector response to alpha particles. The first part of the study focused on the electrical behaviour of as-deposited diamond surface, showing a p type conduction and its influence on the leakage current of the device. A surface preparation process was established in order to reduce the leakage current of the device by surface dehydrogenation using an oxidising step. Several methods to form and treat electrical contacts were also investigated showing that the collection efficiency of the device decreases after contact annealing. In the second part, we reported the influence of the diamond deposition parameters on the characteristics of the detectors. The increase of the deposition temperature and/or methane concentration was shown to lead η to decrease. In contrast, η was found to increase with the micro-wave power. The evolution of the diamond detector characteristics results from the variation in sp 2 phases incorporation and in the crystallography quality of the films. These defects increase the leakage current and reduce the carrier mobility and lifetime. Measurements carried out on detectors with different thicknesses showed that the physical properties varies along the growth direction, improving with the film thickness. Finally, the addition of nitrogen (> 10 ppm) in the gas mixture during diamond deposition was found to strongly reduce the collection efficiency of the detectors. To conclude the study, we fabricated and characterised diamond devices which were used for thermal neutron detection and for the intensity and shape measurement of VUV and soft X-ray pulses. (author)

  1. Method development for the determination of 24S-hydroxycholesterol in human plasma without derivatization by high-performance liquid chromatography with tandem mass spectrometry in atmospheric pressure chemical ionization mode.

    Science.gov (United States)

    Sugimoto, Hiroshi; Kakehi, Masaaki; Satomi, Yoshinori; Kamiguchi, Hidenori; Jinno, Fumihiro

    2015-10-01

    We developed a highly sensitive and specific high-performance liquid chromatography with tandem mass spectrometry method with an atmospheric pressure chemical ionization interface to determine 24S-hydroxycholesterol, a major metabolite of cholesterol formed by cytochrome P450 family 46A1, in human plasma without any derivatization step. Phosphate buffered saline including 1% Tween 80 was used as the surrogate matrix for preparation of calibration curves and quality control samples. The saponification process to convert esterified 24S-hydroxycholesterol to free sterols was optimized, followed by liquid-liquid extraction using hexane. Chromatographic separation of 24S-hydroxycholesterol from other isobaric endogenous oxysterols was successfully achieved with gradient mobile phase comprised of 0.1% propionic acid and acetonitrile using L-column2 ODS (2 μm, 2.1 mm id × 150 mm). This assay was capable of determining 24S-hydroxycholesterol in human plasma (200 μL) ranging from 1 to 100 ng/mL with acceptable intra- and inter-day precision and accuracy. The potential risk of in vitro formation of 24S-hydroxycholesterol by oxidation from endogenous cholesterol in human plasma was found to be negligible. The stability of 24S-hydroxycholesterol in relevant solvents and human plasma was confirmed. This method was successfully applied to quantify the plasma concentrations of 24S-hydroxycholesterol in male and female volunteers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Surface Alloying of SUS 321 Chromium-Nickel Steel by an Electron-Plasma Process

    Science.gov (United States)

    Ivanov, Yu. F.; Teresov, A. D.; Petrikova, E. A.; Krysina, O. V.; Ivanova, O. V.; Shugurov, V. V.; Moskvin, P. V.

    2017-07-01

    The mechanisms of forming nanostructured, nanophase layers are revealed and analyzed in austenitic steel subjected to surface alloying using an electron-plasma process. Nanostructured, nanophase layers up to 30 μm in thickness were formed by melting of the film/substrate system with an electron beam generated by a SOLO facility (Institute of High Current Electronics, SB RAS), Tomsk), which ensured crystallization and subsequent quenching at the cooling rates within the range 105-108 K/s. The surface was modified with structural stainless steel specimens (SUS 321 steel). The film/substrate system (film thickness 0.5 μm) was formed by a plasma-assisted vacuum-arc process by evaporating a cathode made from a sintered pseudoalloy of the following composition: Zr - 6 at.% Ti - 6 at.% Cu. The film deposition was performed in a QUINTA facility equipped with a PINK hot-cathode plasma source and DI-100 arc evaporators with accelerated cooling of the process cathode, which allowed reducing the size and fraction of the droplet phase in the deposited film. It is found that melting of the film/substrate system (Zr-Ti-Cu)/(SUS 321 steel) using a high-intensity pulsed electron beam followed by the high-rate crystallization is accompanied by the formation of α-iron cellular crystallization structure and precipitation of Cr2Zr, Cr3C2 and TiC particles on the cell boundaries, which as a whole allowed increasing microhardness by a factor of 1.3, Young's modulus - by a factor of 1.2, wear resistance - by a factor of 2.7, while achieving a three-fold reduction in the friction coefficient.

  3. Proceedings of the national seminar on significant advancements in plasma/flame/associated techniques and their applications in chemical characterisation of atomic minerals and materials: souvenir

    International Nuclear Information System (INIS)

    Chakrapani, G.; Premdas, A.; Bangroo, P.N.

    2013-01-01

    AAS techniques, novel decomposition methods, plasma techniques, separation, preconcentration, ICP-OPEs, ICP-OES/MS, ICP/other techniques, uranium, review articles and plasma techniques are some of the topics covered in this symposium. Papers relevant to INIS are indexed separately

  4. Plasma polymerization by Softplasma

    DEFF Research Database (Denmark)

    Jiang, J.; Wu, Zhenning; Benter, Maike

    2008-01-01

    , external electrode, and electrodeless microwave or high frequency reactors. [3] Softplasma™ is an internal electrode plasma setup powered by low frequenc~ gower supply. It was developed in late 90s for surface treatment of silicone rubber. [ ]- 5] It is a low pressure, low electron density, 3D homogenous......In the late 19th century, the first depositions - known today as plasma polymers, were reported. In the last century, more and more research has been put into plasma polymers. Many different deposition systems have been developed. [1, 2] Shi F. F. broadly classified them into internal electrode...... plasma. In this study, we are presenting the surface modification"pf polymers by plasma polymerization using Softplasma™. Softplasma™ can be used for two major types of polymerization: polymerization of vinyl monomers, where plasma acts as initiator; chemical vapour deposition, where plasma acts...

  5. Physico-chemical induced modification of seed germination and early development in artichoke (Cynara scolymus L.) using low energy plasma technology

    Science.gov (United States)

    Hosseini, Seyed Iman; Mohsenimehr, Soad; Hadian, Javad; Ghorbanpour, Mansour; Shokri, Babak

    2018-01-01

    In this study, low pressure non-thermal radiofrequency nitrogen plasma at very low power has been used to treat the artichoke seeds on the powered cathode for the first time. The influence of treatment time on the surface physical properties, germination rate, seedling growth, and enzyme activity of the seeds has been investigated. Results showed that plasma treatment considerably improved the germination rate and seedling growth. The root length grew by 28.5% and 50% and root dry weight increased by 13% and 53%, respectively, for 10 and 15 min of treatment. The same trend has been found for the shoot growth parameters although the greater stimulatory efficacy on root has been obtained. The nitrogen plasma treatment substantially made the seeds' surface hydrophilic which leads to 36.9% improvement in seed's water uptake at 15 min of treatment. Our study showed the activity of peroxidase and catalase enzymes slightly increased after the plasma treatment.

  6. Apparatus for chemical synthesis

    Science.gov (United States)

    Kong, Peter C [Idaho Falls, ID; Herring, J Stephen [Idaho Falls, ID; Grandy, Jon D [Idaho Falls, ID

    2011-05-10

    A method and apparatus for forming a chemical hydride is described and which includes a pseudo-plasma-electrolysis reactor which is operable to receive a solution capable of forming a chemical hydride and which further includes a cathode and a movable anode, and wherein the anode is moved into and out of fluidic, ohmic electrical contact with the solution capable of forming a chemical hydride and which further, when energized produces an oxygen plasma which facilitates the formation of a chemical hydride in the solution.

  7. Epitaxial growth of GaN by radical-enhanced metalorganic chemical vapor deposition (REMOCVD) in the downflow of a very high frequency (VHF) N2/H2 excited plasma - effect of TMG flow rate and VHF power

    Science.gov (United States)

    Lu, Yi; Kondo, Hiroki; Ishikawa, Kenji; Oda, Osamu; Takeda, Keigo; Sekine, Makoto; Amano, Hiroshi; Hori, Masaru

    2014-04-01

    Gallium nitride (GaN) films have been grown by using our newly developed Radical-Enhanced Metalorganic Chemical Vapor Deposition (REMOCVD) system. This system has three features: (1) application of very high frequency (60 MHz) power in order to increase the plasma density, (2) introduction of H2 gas together with N2 gas in the plasma discharge region to generate not only nitrogen radicals but also active NHx molecules, and (3) radical supply under remote plasma arrangement with suppression of charged ions and photons by employing a Faraday cage. Using this new system, we have studied the effect of the trimethylgallium (TMG) source flow rate and of the plasma generation power on the GaN crystal quality by using scanning electron microscopy (SEM) and double crystal X-ray diffraction (XRD). We found that this REMOCVD allowed the growth of epitaxial GaN films of the wurtzite structure of (0001) orientation on sapphire substrates with a high growth rate of 0.42 μm/h at a low temperature of 800 °C. The present REMOCVD is a promising method for GaN growth at relatively low temperature and without using costly ammonia gas.

  8. Plasma Processing of Metallic and Semiconductor Thin Films in the Fisk Plasma Source

    Science.gov (United States)

    Lampkin, Gregory; Thomas, Edward, Jr.; Watson, Michael; Wallace, Kent; Chen, Henry; Burger, Arnold

    1998-01-01

    The use of plasmas to process materials has become widespread throughout the semiconductor industry. Plasmas are used to modify the morphology and chemistry of surfaces. We report on initial plasma processing experiments using the Fisk Plasma Source. Metallic and semiconductor thin films deposited on a silicon substrate have been exposed to argon plasmas. Results of microscopy and chemical analyses of processed materials are presented.

  9. The plasma universe

    International Nuclear Information System (INIS)

    Faelthammar, C.G.

    1989-12-01

    The term 'Plasma Universe', coined by Hannes Alfven, emphasices the fact that plasma phenomena discovered in the laboratory and in accessible regions of space. must be important also in the rest of the universe, which consists almost entirely of matter in the plasma state. Relevant aspect of this concept will be discussed. They include the response of the plasma to electric currents, the support of magnetic-field aligned electric fields, violation of the frozen-field condition, rapid release of magnetically stored energy, acceleration of charged particles, chemical separation, and filamentary and cellular structures. (authors)

  10. Identification of known chemicals and their metabolites from Alpinia oxyphylla fruit extract in rat plasma using liquid chromatography/tandem mass spectrometry (LC-MS/MS) with selected reaction monitoring.

    Science.gov (United States)

    Chen, Feng; Li, Hai-Long; Tan, Yin-Feng; Li, Yong-Hui; Lai, Wei-Yong; Guan, Wei-Wei; Zhang, Jun-Qing; Zhao, Yuan-Sheng; Qin, Zhen-Miao

    2014-08-01

    Alpinia oxyphylla (Yizhi) capsularfruits are commonly used in traditional medicine. Pharmacological studies have demonstrated that A. oxyphylla capsularfruits have some beneficial roles. Besides volatile oil, sesquiterpenes, diarylheptanoids and flavonoids are main bioactive constituents occurring in the Yizhi capsularfruits. The representative constituents include tectochrysin, izalpinin, chrysin, apigenin-4',7-dimethylether, kaempferide, yakuchinone A, yakuchinone B, oxyphyllacinol and nootkatone. Their content levels in the fruit and its pharmaceutical preparations have been reported by our group. The nine phytochemicals are also the major components present in the Yizhi alcoholic extracts, which have anti-diarrheal activities. However, the fates of these constituents in the body after oral or intravenous administration remain largely unknown. In the present study, we focus on these phytochemicals albeit other concomitant compounds. The chemicals and their metabolites in rat plasma were identified using liquid chromatography/tandem mass spectrometry with selected reaction monitoring mode after orally administered Yizhi extract to rats. Rat plasma samples were treated by methanol precipitation, acidic or enzymatic hydrolysis. This target analysis study revealed that: (1) low or trace plasma levels of parent chemicals were measured after p.o. administration of Yizhi extract, Suoquan capsules and pills to rats; (2) flavonoids and diarylheptanoids formed mainly monoglucuronide metabolites; however, diglucuronide metabolites for chrysin, izalpinin and kaempferide were also detected; (3) metabolic reduction of Yizhi diarylheptanoids occurred in rats. Yakuchinone B was reduced to yakuchinone A and then to oxyphyllacinol in a stepwise manner and subsequently glucuronidated by UDP-glucuronosyl transferase. Further research is needed to characterize the UDP-glucuronosyl transferase and reductase involved in the biotransformation of Yizhi chemicals. Copyright © 2014

  11. Effects of gas residence time of CH4/H2 on sp2 fraction of amorphous carbon films and dissociated methyl density during radical-injection plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Sugiura, Hirotsugu; Jia, Lingyun; Kondo, Hiroki; Ishikawa, Kenji; Tsutsumi, Takayoshi; Hayashi, Toshio; Takeda, Keigo; Sekine, Makoto; Hori, Masaru

    2018-06-01

    Quadruple mass spectrometric measurements of CH3 density during radical-injection plasma-enhanced chemical vapor deposition to consider the sp2 fraction of amorphous carbon (a-C) films were performed. The sp2 fraction of the a-C films reached a minimum of 46%, where the CH3 density was maximum for a residence time of 6 ms. The sp2 fraction of the a-C films was tailored with the gaseous phase CH3 density during the deposition. This knowledge is useful for understanding the formation mechanism of bonding structures in the a-C films, which enables the precise control of their electronic properties.

  12. Effects of O2 and H2O plasma immersion ion implantation on surface chemical composition and surface energy of poly vinyl chloride

    International Nuclear Information System (INIS)

    Zhang Wei; Chu, Paul K.; Ji Junhui; Zhang, Yihe; Jiang Zhimin

    2006-01-01

    Oxygen and water plasma immersion ion implantation (PIII) was used to modify poly vinyl chloride (PVC) to enhance oxygen-containing surface functional groups for more effective grafting. The modified surfaces were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and contact angle measurements. Our experimental results show that both oxygen and water PIII can greatly improve the O to C ratios on the surface. The optimal plasma processing conditions differ for the two treatments. The hydrophilicity and surface energy of the plasma-implanted PVC are also improved significantly. Our results indicate that O 2 and H 2 O PIII increase both the polar and dispersion interactions and consequently the surface energy. It can be explained by the large amount of oxygen introduced to the surface and that many C-C bonds are transformed into more polar oxygen containing functional groups

  13. Introduction to complex plasmas

    International Nuclear Information System (INIS)

    Bonitz, Michael; Ludwig, Patrick; Horing, Norman

    2010-01-01

    Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates. (orig.)

  14. Introduction to Complex Plasmas

    CERN Document Server

    Bonitz, Michael; Ludwig, Patrick

    2010-01-01

    Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates.

  15. Method for the detection of Tc in seaweed samples coupling the use of Re as a chemical tracer and isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Mas, Jose Luis; Tagami, Keiko; Uchida, Shigeo

    2004-01-01

    Analysis of the artificial radionuclide 99 Tc in environmental samples requires a chemical separation due to its low concentration, and therefore the use of a chemical yield tracer is peremptory. From a practical viewpoint, Re can be used for this purpose, due to its chemical similarities with Tc. Thus, the use of a radioactive tracer for Tc recovery calculation can be avoided. However, results from a recent intercomparison exercise showed that using of Re as a chemical yield tracer appears to underestimate the Tc concentration relative to the result obtained with isotopes of Tc. In the present work, the methodology used to design a simple separation method for the measurement of 99 Tc in environmental samples is described. Tc recovery is estimated throughout the Re recovery calculation by the isotope dilution technique coupled with ICP-MS (ID-ICP-MS) technique. For chemical separation, a chromatographic resin is used. Interfering elements are removed using a resin washing step carefully designed to avoid any element fractionation between Re and Tc; the care taken in this step is of major importance to assure the equivalence of the chemical recoveries for both elements. Agreement is tested using five replicates of five seaweed samples. The average recoveries for 95m Tc and Re were 93±6 and 95±7%, respectively, those are within the uncertainty intervals for each other. The results explained here demonstrate the possibility of applying Re chemical recoveries to calculate the Tc concentrations with the advantage of not introducing systematic errors

  16. Determination of phenolic derivatives of antipyrine in plasma with solid-phase extraction and high-performance liquid chromatography-atmospheric-pressure chemical ionization mass spectrometry

    NARCIS (Netherlands)

    Coolen, S.A.J.; Ligor, T.; Lieshout, van H.P.M.; Huf, F.A.

    1999-01-01

    This manuscript describes a method to determine antipyrine and its phenolic derivatives in plasma by reversed-phase high-performance liquid chromatography–mass spectrometry (RP-HPLC–MS). The sample pretreatment consisted of a C18 solid-phase extraction (SPE), to remove the salts and proteins. The

  17. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nad, Shreya [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Gu, Yajun; Asmussen, Jes [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)

    2015-07-15

    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100–260 Torr pressure range and 1.5–2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (η{sub coup}) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance.

  18. Physico-chemical and mechanical modifications of polyethylene and polypropylene by ion implantation, micro-wave plasma, electron beam radiation and gamma ray irradiation; Modifications physico-chimiques et mecaniques du polyethylene et du polypropylene par implantation ionique, plasma micro-ondes, bombardement d`electrons et irradiation gamma

    Energy Technology Data Exchange (ETDEWEB)

    Liao, J D

    1995-03-29

    A polyolefin surface becomes wettable when treated by micro-wave plasma or low-dose nitrogen ion implantation. A short time argon plasma treatment is sufficient to obtain polarizable peroxides on a polyolefin. X-ray photoelectron spectroscopy analyses, paramagnetic electronic resonance analyses, peroxides decomposition, wettability measurements and infrared active spectra analyses have shown that oxidized structures obtained from different treatment techniques play an important role in the interpretation of surface chemical properties of the polymer. Micro-wave plasma treatment, and in particular argon plasma treatment, yields more polarizable groups than ion implantation and is interesting for grafting. Hardness and elasticity modulus, measured by nano-indentation on a polyolefin, increase with an appropriate ion implantation dose. A 1.4 x 10{sup 17} ions.cm{sup -2} dose can multiply by 15 the hardness of high molecular weight polyethylene, and by 7 the elasticity modulus for a 30 nm depth. The viscous-plastic to quasi-elastic transition is shown. The thickness of the modified layer is over 300 nm. The study of friction between a metal sphere and a polyethylene cupula shows that ion implantation in the polymer creates a reticulated hard and elastic layer which improves its mechanical properties and reduces the erosion rate. Surface treatments on polymers used as biomaterials allow to adapt the surface properties to specific applications. 107 refs., 66 figs., 19 tabs., 4 annexes.

  19. fabrics induced by cold plasma treatments

    Indian Academy of Sciences (India)

    Some selective cold plasma processing modify specific surface properties of ... obtain information on the chemical and physical processing involved in ... charges of suitable gases. such plasma species can give rise to several concurrent.

  20. Qualitative and quantitative spectro-chemical analysis of dates using UV-pulsed laser induced breakdown spectroscopy and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Mehder, A O; Habibullah, Y B; Gondal, M A; Baig, Umair

    2016-08-01

    Laser Induced Breakdown Spectroscopy (LIBS) is demonstrated for the spectral analysis of nutritional and toxic elements present in several varieties of date fruit samples available in the Saudi Arabia market. The method analyzes the optical emission of a test sample when subjected to pulsed laser ablation. In this demonstration, our primary focus is on calcium (Ca) and magnesium (Mg), as nutritional elements, and on chromium (Cr), as a toxic element. The local thermodynamic equilibrium (LTE) condition was confirmed prior to the elemental characterization of date samples to ensure accuracy of the LIBS analysis. This was achieved by measuring parameters associated with the plasma, such as the electron temperature and the electron number density. These plasma parameters aid interpretation of processes such as ionization, dissociation, and excitation occurring in the plasma plume formed by ablating the date palm sample. The minimum detection limit was established from calibration curves that involved plotting the LIBS signal intensity as a function of standard date samples with known concentrations. The concentration of Ca and Mg detected in different varieties of date samples was between 187 and 515 and 35-196mgL(-1) respectively, while Cr concentration measured between 1.72 and 7.76mgL(-1). In order to optimize our LIBS system, we have studied how the LIBS signal intensity depends on the incident laser energy and the delay time. In order to validate our LIBS analysis results, standard techniques such as inductively coupled plasma mass spectrometry (ICP-MS) were also applied on an identical (duplicate) date samples as those used for the LIBS analysis. The LIBS results exhibit remarkable agreement with those obtained from the ICP-MS analysis. In addition, the finger print wavelengths of other elements present in date samples were also identified and are reported here, which has not been previously reported, to the best of our knowledge. Copyright © 2016 Elsevier B

  1. Ellipsometric investigation of nitrogen doped diamond thin films grown in microwave CH{sub 4}/H{sub 2}/N{sub 2} plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ficek, Mateusz, E-mail: rbogdan@eti.pg.gda.pl [Department of Metrology and Optoelectronics, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 11/12 G. Narutowicza St., 80-233 Gdansk (Poland); Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Sankaran, Kamatchi J.; Haenen, Ken [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Ryl, Jacek; Darowicki, Kazimierz [Department of Electrochemistry, Corrosion and Material Engineering, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk (Poland); Bogdanowicz, Robert [Department of Metrology and Optoelectronics, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 11/12 G. Narutowicza St., 80-233 Gdansk (Poland); Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125 (United States); Lin, I-Nan [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    2016-06-13

    The influence of N{sub 2} concentration (1%–8%) in CH{sub 4}/H{sub 2}/N{sub 2} plasma on structure and optical properties of nitrogen doped diamond (NDD) films was investigated. Thickness, roughness, and optical properties of the NDD films in the VIS–NIR range were investigated on the silicon substrates using spectroscopic ellipsometry. The samples exhibited relatively high refractive index (2.6 ± 0.25 at 550 nm) and extinction coefficient (0.05 ± 0.02 at 550 nm) with a transmittance of 60%. The optical investigation was supported by the molecular and atomic data delivered by Raman studies, bright field transmission electron microscopy imaging, and X-ray photoelectron spectroscopy diagnostics. Those results revealed that while the films grown in CH{sub 4}/H{sub 2} plasma contained micron-sized diamond grains, the films grown using CH{sub 4}/H{sub 2}/(4%)N{sub 2} plasma exhibited ultranano-sized diamond grains along with n-diamond and i-carbon clusters, which were surrounded by amorphous carbon grain boundaries.

  2. Predictable topography simulation of SiO2 etching by C5F8 gas combined with a plasma simulation, sheath model and chemical reaction model

    International Nuclear Information System (INIS)

    Takagi, S; Onoue, S; Iyanagi, K; Nishitani, K; Shinmura, T; Kanoh, M; Itoh, H; Shioyama, Y; Akiyama, T; Kishigami, D

    2003-01-01

    We have developed a simulation for predicting reactive ion etching (RIE) topography, which is a combination of plasma simulation, the gas reaction model, the sheath model and the surface reaction model. The simulation is applied to the SiO 2 etching process of a high-aspect-ratio contact hole using C 5 F 8 gas. A capacitively coupled plasma (CCP) reactor of an 8-in. wafer was used in the etching experiments. The baseline conditions are RF power of 1500 W and gas pressure of 4.0 Pa in a gas mixture of Ar, O 2 and C 5 F 8 . The plasma simulation reproduces the tendency that CF 2 radical density increases rapidly and the electron density decreases gradually with increasing gas flow rate of C 5 F 8 . In the RIE topography simulation, the etching profiles such as bowing and taper shape at the bottom are reproduced in deep holes with aspect ratios greater than 19. Moreover, the etching profile, the dependence of the etch depth on the etching time, and the bottom diameter can be predicted by this simulation

  3. Physico-chemical study of coating plasma duplex alumina/hydroxyapatite for medical applications relation elaboration/structure/properties(dissolution/adherence/residual constraints); Etude physico-chimique de depots plasma duplex alumine/hydroxyapatite pour applications medicales relations elaboration/structure/proprietes (dissolution/adherence/contraintes residuelles)

    Energy Technology Data Exchange (ETDEWEB)

    Demonet, N

    1998-11-19

    The physico-chemical behavior of porous ceramics depositing is studied in order to use them to favour the biological fixing of hip prosthesis fixed without cement. Alumina depositing, hydroxyapatite depositing and duplex (the both together) have been realized by plasma projection on a substrate in Ti-6Al-V. Tests of dissolution have been made. An original method of sound followed by radioactive tracers has allowed to establish an order of phases degradation and to consider the kinetics of calcium ions in function of several parameters of tests. (N.C.)

  4. Fuel gas production by microwave plasma in liquid

    International Nuclear Information System (INIS)

    Nomura, Shinfuku; Toyota, Hiromichi; Tawara, Michinaga; Yamashita, Hiroshi; Matsumoto, Kenya

    2006-01-01

    We propose to apply plasma in liquid to replace gas-phase plasma because we expect much higher reaction rates for the chemical deposition of plasma in liquid than for chemical vapor deposition. A reactor for producing microwave plasma in a liquid could produce plasma in hydrocarbon liquids and waste oils. Generated gases consist of up to 81% hydrogen by volume. We confirmed that fuel gases such as methane and ethylene can be produced by microwave plasma in liquid

  5. Plasma turbulence

    International Nuclear Information System (INIS)

    Horton, W.

    1998-07-01

    The origin of plasma turbulence from currents and spatial gradients in plasmas is described and shown to lead to the dominant transport mechanism in many plasma regimes. A wide variety of turbulent transport mechanism exists in plasmas. In this survey the authors summarize some of the universally observed plasma transport rates

  6. Plasma properties

    International Nuclear Information System (INIS)

    Weitzner, H.

    1990-06-01

    This paper discusses the following topics: MHD plasma activity: equilibrium, stability and transport; statistical analysis; transport studies; edge physics studies; wave propagation analysis; basic plasma physics and fluid dynamics; space plasma; and numerical methods

  7. Plasma accelerators

    International Nuclear Information System (INIS)

    Bingham, R.; Angelis, U. de; Johnston, T.W.

    1991-01-01

    Recently attention has focused on charged particle acceleration in a plasma by a fast, large amplitude, longitudinal electron plasma wave. The plasma beat wave and plasma wakefield accelerators are two efficient ways of producing ultra-high accelerating gradients. Starting with the plasma beat wave accelerator (PBWA) and laser wakefield accelerator (LWFA) schemes and the plasma wakefield accelerator (PWFA) steady progress has been made in theory, simulations and experiments. Computations are presented for the study of LWFA. (author)

  8. The investigation of structure, chemical composition, hydrogen isotope trapping and release processes in deposition layers on surfaces exposed to DIII-D divertor plasma

    International Nuclear Information System (INIS)

    Buzhinskij, O.I.; Opimach, I.V.; Barsuk, V.A.; Arkhipov, I.I.; Whyte, D.; Wampler, W.R.

    1998-05-01

    The exposure of ATG graphite sample to DIII-D divertor plasma was provided by the DiMES (Divertor Material Evaluation System) mechanism. The graphite sample arranged to receive the parallel heat flux on a small region of the surface was exposed to 600ms of outer strike point plasma. The sample was constructed to collect the eroded material directed downward into a trapping zone onto s Si disk collector. The average heat flux onto the graphite sample during the exposure was about 200W/cm 2 , and the parallel heat flux was about 10 KW/cm 2 . After the exposure the graphite sample and Si collector disk were analyzed using SEM, NRA, RBS, Auger spectroscopy. IR and Raman spectroscopy. The thermal desorption was studied also. The deposited coating on graphite sample is amorphous carbon layer. Just upstream of the high heat flux zone the redeposition layer has a globular structure. The deposition layer on Si disk is composed also from carbon but has a diamond-like structure. The areal density of C and D in the deposited layer on Si disk varied in poloidal and toroidal directions. The maximum D/C areal density ratio is about 0.23, maximum carbon density is about 3.8 x 10 18 cm -2 , maximum D area density is about 3 x 10 17 cm 2 . The thermal desorption spectrum had a peak at 1,250K

  9. Thin films of hydrogenated amorphous carbon (a-C:H) obtained through chemical vapor deposition assisted by plasma; Peliculas delgadas de carbono amorfo hidrogenado (a-C:H) obtenidas mediante deposito quimico de vapores asistido por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Mejia H, J.A.; Camps C, E.E.; Escobar A, L.; Romero H, S.; Chirino O, S. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Muhl S, S. [IIM-UNAM, 04510 Mexico D.F. (Mexico)

    2004-07-01

    Films of hydrogenated amorphous carbon (a-C:H) were deposited using one source of microwave plasma with magnetic field (type ECR), using mixtures of H{sub 2}/CH{sub 4} in relationship of 80/20 and 95/05 as precursory gases, with work pressures of 4X10{sup -4} to 6x10{sup -4} Torr and an incident power of the discharge of microwaves with a constant value of 400 W. It was analyzed the influence among the properties of the films, as the deposit rate, the composition and the bonding types, and the deposit conditions, such as the flow rates of the precursory gases and the polarization voltage of the sample holders. (Author)

  10. Review on plasmas in extraordinary media: plasmas in cryogenic conditions and plasmas in supercritical fluids

    Science.gov (United States)

    Stauss, Sven; Muneoka, Hitoshi; Terashima, Kazuo

    2018-02-01

    Plasma science and technology has enabled advances in very diverse fields: micro- and nanotechnology, chemical synthesis, materials fabrication and, more recently, biotechnology and medicine. While many of the currently employed plasma tools and technologies are very advanced, the types of plasmas used in micro- and nanofabrication pose certain limits, for example, in treating heat-sensitive materials in plasma biotechnology and plasma medicine. Moreover, many physical properties of plasmas encountered in nature, and especially outer space, i.e. very-low-temperature plasmas or plasmas that occur in high-density media, are not very well understood. The present review gives a short account of laboratory plasmas generated under ’extreme’ conditions: at cryogenic temperatures and in supercritical fluids. The fundamental characteristics of these cryogenic plasmas and cryoplasmas, and plasmas in supercritical fluids, especially supercritical fluid plasmas, are presented with their main applications. The research on such exotic plasmas is expected to lead to further understanding of plasma physics and, at the same time, enable new applications in various technological fields.

  11. Using KrF ELA to Improve Gate-Stacked LaAlO₃/ZrO₂ Indium Gallium Zinc Oxide Thin-Film Transistors with Novel Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition Technique.

    Science.gov (United States)

    Wu, Chien-Hung; Chang, Kow-Ming; Chen, Yi-Ming; Huang, Bo-Wen; Zhang, Yu-Xin; Wang, Shui-Jinn

    2018-03-01

    Atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) technique and KrF excimer laser annealing (ELA) were employed for the fabrication of indium gallium zinc oxide thin-film transistors (IGZO-TFTs). Device with a 150 mJ/cm2 laser annealing densities demonstrated excellent electrical characteristics with improved on/off current ratio of 4.7×107, high channel mobility of 10 cm2/V-s, and low subthreshold swing of 0.15 V/dec. The improvements are attributed to the adjustment of oxygen vacancies in the IGZO channel to an appropriate range of around 28.3% and the reduction of traps at the high-k/IGZO interface.

  12. Long-term stable water vapor permeation barrier properties of SiN/SiCN/SiN nanolaminated multilayers grown by plasma-enhanced chemical vapor deposition at extremely low pressures

    International Nuclear Information System (INIS)

    Choi, Bum Ho; Lee, Jong Ho

    2014-01-01

    We investigated the water vapor permeation barrier properties of 30-nm-thick SiN/SiCN/SiN nanolaminated multilayer structures grown by plasma enhanced chemical vapor deposition at 7 mTorr. The derived water vapor transmission rate was 1.12 × 10 −6 g/(m 2 day) at 85 °C and 85% relative humidity, and this value was maintained up to 15 000 h of aging time. The X-ray diffraction patterns revealed that the nanolaminated film was composed of an amorphous phase. A mixed phase was observed upon performing high resolution transmission electron microscope analysis, which indicated that a thermodynamically stable structure was formed. It was revealed amorphous SiN/SiCN/SiN multilayer structures that are free from intermixed interface defects effectively block water vapor permeation into active layer

  13. Multivariate innovative approaches to the treatment of the emission of LIBS plasmas. Application to chemical online analysis in a nuclear environment

    International Nuclear Information System (INIS)

    El-Rakwe, Maria

    2016-01-01

    Online and in situ analysis is now a strategic development for analytical chemistry. This is especially true in the nuclear field for which the security constraints related to the radioactivity of samples, and the need to minimize waste from analyzes argue for remote measurement techniques without sampling or sample preparation. Laser-Induced Breakdown Spectroscopy (LIBS) technique for elemental analysis of materials based on laser ablation and the optical emission spectroscopy, has these qualities. It is a technique of choice for online analysis. However, processes involved in LIBS, namely laser ablation, atomization, plasma formation and emission, are quite complex and difficult to control because the underlying physical phenomena are coupled and nonlinear. In addition, the analytical performance of the LIBS technique depends strongly on the choice of experimental conditions. Finally, an online analysis system should be as robust as possible face to uncontrolled variations in measurement conditions. The objective of this thesis is to improve control and performance of quantitative analysis by LIBS using multivariate methods capable of handling multi-dimensionality, nonlinearity and the coupling between parameters and data. For this, the work is divided into two parts. First the optimization is carried out using a central composite design to model the relationship between the experimental parameters of laser ablation (pulse energy and beam focusing parameters) and signal detection (delay time) to the physical characteristics of plasma (ablated mass, temperature) and the analytical performance (intensity and repeatability of the signal). The optimization parameters that results is then interpreted as the best compromise for the quantitative analysis between efficiency of laser ablation and plasma heating. Secondly, a multivariate methodology based on MCR-ALS, ICA and PLS techniques, was developed to quantify certain elements in different metallic matrices

  14. Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) yields better Hydrolytical Stability of Biocompatible SiOx Thin Films on Implant Alumina Ceramics compared to Rapid Thermal Evaporation Physical Vapor Deposition (PVD).

    Science.gov (United States)

    Böke, Frederik; Giner, Ignacio; Keller, Adrian; Grundmeier, Guido; Fischer, Horst

    2016-07-20

    Densely sintered aluminum oxide (α-Al2O3) is chemically and biologically inert. To improve the interaction with biomolecules and cells, its surface has to be modified prior to use in biomedical applications. In this study, we compared two deposition techniques for adhesion promoting SiOx films to facilitate the coupling of stable organosilane monolayers on monolithic α-alumina; physical vapor deposition (PVD) by thermal evaporation and plasma enhanced chemical vapor deposition (PE-CVD). We also investigated the influence of etching on the formation of silanol surface groups using hydrogen peroxide and sulfuric acid solutions. The film characteristics, that is, surface morphology and surface chemistry, as well as the film stability and its adhesion properties under accelerated aging conditions were characterized by means of X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and tensile strength tests. Differences in surface functionalization were investigated via two model organosilanes as well as the cell-cytotoxicity and viability on murine fibroblasts and human mesenchymal stromal cells (hMSC). We found that both SiOx interfaces did not affect the cell viability of both cell types. No significant differences between both films with regard to their interfacial tensile strength were detected, although failure mode analyses revealed a higher interfacial stability of the PE-CVD films compared to the PVD films. Twenty-eight day exposure to simulated body fluid (SBF) at 37 °C revealed a partial delamination of the thermally deposited PVD films whereas the PE-CVD films stayed largely intact. SiOx layers deposited by both PVD and PE-CVD may thus serve as viable adhesion-promoters for subsequent organosilane coupling agent binding to α-alumina. However, PE-CVD appears to be favorable for long-term direct film exposure to aqueous

  15. Preparation of hydrogenated amorphous carbon films using a microsecond-pulsed DC capacitive-coupled plasma chemical vapor deposition system operated at high frequency up to 400 kHz

    Science.gov (United States)

    Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

    2018-06-01

    Hydrogenated amorphous carbon (a-C:H) films are deposited on silicon (Si) substrates using a high-repetition microsecond-pulsed DC plasma chemical vapor deposition (CVD) system from acetylene (C2H2) at a gas pressure of 15 Pa inside a custom-made vacuum chamber. The plasma discharge characteristics, hydrocarbon species, and the microstructure of the resulting films are examined at various pulse repetition rates from 50 to 400 kHz and a fixed duty cycle of 50%. The optical emission spectra confirmed the increase in electron excitation energy from 1.09 to 1.82 eV and the decrease in the intensity ratio of CH/C2 from 1.04 to 0.75 with increasing pulse frequency, indicating the enhanced electron impact dissociation of C2H2 gas. With increasing pulse frequency, the deposition rate gradually increased, reaching a maximum rate of 60 nm/min at 200 kHz, after which a progressive decrease was noted, whereas the deposition area was almost uniform for all the prepared films. Clear trends of increasing sp3 content (amorphization) and decreasing hydrogen (H) content in the films were observed as the pulse repetition rate increased, while most of the hydrogen atoms bonded to carbon atoms by sp3 hybridization rather than by sp2 hybridization.

  16. Structure and gas-barrier properties of amorphous hydrogenated carbon films deposited on inner walls of cylindrical polyethylene terephthalate by plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Li Jing; Gong Chunzhi; Tian Xiubo; Yang Shiqin; Fu, Ricky K.Y.; Chu, Paul K.

    2009-01-01

    The influence of radio-frequency (RF) power on the structure and gas permeation through amorphous hydrogenated carbon films deposited on cylindrical polyethylene terephthalate (PET) samples is investigated. The results show that a higher radio-frequency power leads to a smaller sp 3 /sp 2 value but produces fewer defects with smaller size. The permeability of PET samples decreases significantly after a-C:H deposition and the RF only exerts a small influence. However, the coating uniformity, color, and wettability of the surface are affected by the RF power. A higher RF power results in to better uniformity and it may be attributed to the combination of the high-density plasma and sample heating.

  17. Plasma chemistry and organic synthesis

    Science.gov (United States)

    Tezuka, M.

    1980-01-01

    The characteristic features of chemical reactions using low temperature plasmas are described and differentiated from those seen in other reaction systems. A number of examples of applications of plasma chemistry to synthetic reactions are mentioned. The production of amino acids by discharge reactions in hydrocarbon-ammonia-water systems is discussed, and its implications for the origins of life are mentioned.

  18. Some aspects of theory and mathematics of thermal runaway in reacting chemical systems that may be relevant to critical behaviour in confined plasmas

    International Nuclear Information System (INIS)

    Ball, R. The

    1999-01-01

    The concept of an endothermally stabilised chemical reactor as an enthalpy coupled thermokinetic system is introduced, and given precise mathematical expression in the form of a four-dimensional dynamical system. Criteria are defined for which the system is free of all kinds of thermal misbehaviour. This important dynamical result defines bounds for a large region of the parameter space within which the reactor may be operated safely. The formalism of singularity theory is extended to bifurcation surfaces in a studio of multiplicity and stability in the CSTR problem

  19. Spectroscopic Study of Recombination in the Early Afterglow of a Helium Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Stevefelt, J

    1968-02-15

    Some properties of a decaying helium plasma have been studied using time resolved spectroscopy and probe diagnostics. The plasma was produced in a pulsed, repetitive, hot cathode discharge in helium at a pressure 11 torr , and the light emitted in the afterglow of the discharge was measured by means of a spectrometer-photomultiplier combination. Single photoelectrons were counted on a scaler during a preset gate time of each discharge cycle, and after a preset number of cycles recorded on punched tape. The spectrometer was calibrated for absolute intensity measurements of the spectral lines of atomic helium. The overall conductance of the positive column was determined by measuring the voltage difference between two probes inserted into the plasma, passing a very small current pulse between the anode and cathode in the afterglow. Heavier current pulses were used to heat the free electrons selectively, thus providing so-called 'afterglow quenching'. From the measured absolute intensities of the helium lines, the number densities of the excited states of helium were calculated. All levels with principal quantum number n {>=} 8 were found to be in near Saha equilibrium with the free electrons at a temperature 1,275 deg K in the early afterglow (15-35 {mu}s after end of the discharge). By measuring the absolute intensities of some of the molecular helium bands, an estimate of the rate of conversion of atomic helium ions into molecular helium ions was obtained. The atomic line radiation, as well as the molecular band radiation, was assumed to result from collisional-radiative recombination of atomic and molecular helium ions, respectively. The rate of recombination down to the metastable level n = 2 was obtained from the measured line intensities. By adding the rate of ambipolar diffusion, calculated from known literature data, quite good agreement with the measured decay rate for the electron density was found. The measured line intensities were also used to calculate

  20. Plasma device

    International Nuclear Information System (INIS)

    Thode, L.E.

    1981-01-01

    A method is described for electron beam heating of a high-density plasma to drive a fast liner. An annular or solid relativistic electron beam is used to heat a plasma to kilovolt temperatures through streaming instabilities in the plasma. Energy deposited in the plasma then converges on a fast liner to explosively or ablatively drive the liner to implosion. (U.K.)