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Sample records for remote plasma enhanced

  1. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    SciTech Connect

    Dechana, A.; Thamboon, P.; Boonyawan, D.

    2014-10-15

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al{sub 2}O{sub 3} layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al{sub 2}O{sub 3} films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  2. Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber

    NASA Astrophysics Data System (ADS)

    Dechana, A.; Thamboon, P.; Boonyawan, D.

    2014-10-01

    A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al2O3 layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al2O3 films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

  3. Analysis of mass transport in an atmospheric pressure remote plasma-enhanced chemical vapor deposition process

    SciTech Connect

    Cardoso, R. P.; Belmonte, T.; Henrion, G.; Gries, T.; Tixhon, E.

    2010-01-15

    In remote microwave plasma enhanced chemical vapor deposition processes operated at atmospheric pressure, high deposition rates are associated with the localization of precursors on the treated surface. We show that mass transport can be advantageously ensured by convection for the heavier precursor, the lighter being driven by turbulent diffusion toward the surface. Transport by laminar diffusion is negligible. The use of high flow rates is mandatory to have a good mixing of species. The use of an injection nozzle with micrometer-sized hole enables us to define accurately the reaction area between the reactive species. The localization of the flow leads to high deposition rates by confining the reactive species over a small area, the deposition yield being therefore very high. Increasing the temperature modifies nonlinearly the deposition rates and the coating properties.

  4. Evidence for the occurrence of subcutaneous oxidation during low temperature remote plasma enhanced deposition of silicon dioxide films

    NASA Astrophysics Data System (ADS)

    Fountain, G. G.; Hattangady, S. V.; Rudder, R. A.; Markunas, R. J.; Lucovsky, G.

    1989-06-01

    The paper presents evidence which indicates that a subcutaneous oxidation process takes place during remote plasma enhanced chemical vapor deposition of SiO2, which oxidizes a few monolayers of the underlying substrate. Electrical measurements on metal-insulator semiconductor (MIS) structures fabricated on Ge and GaAs materials are presented. It is found that the performance of Si metal-oxide semiconductor structures fabricated using deposited oxides degrades as the thickness of the oxide is increased.

  5. Deposition of Amorphous Silicon and Silicon-Based Dielectrics by Remote Plasma-Enhanced Chemical Vapor Deposition: Application to the Fabrication of Tft's and Mosfet's.

    NASA Astrophysics Data System (ADS)

    Kim, Sang Soo

    1990-01-01

    This thesis discusses the deposition of device quality silicon dioxide (SiO_2), silicon nitride (Si_3N_4 ), and hydrogenated amorphous silicon (a-Si:H) by the remote plasma enhanced chemical vapor deposition (Remote PECVD) technique at low substrate temperature (100 ^circC < T _{rm s} < 450^ circC). An ultra-high-vacuum (UHV) compatible, multi-chamber integrated processing system has been built and used for this study. This system provides: (1) in -situ substrate processing; (2) surface analysis by Auger electron spectroscopy (AES) and reflected high energy electron diffraction (RHEED); and (3) thin film deposition by Remote PECVD. Six issues are addressed: (1) in-situ semiconductor surface cleaning for Si, Ge, GaAs, and CdTe; (2) substrate surface characterization by using RHEED and AES; (3) process gas-substrate interactions (subcutaneous oxidation) occurring during the thin film deposition; (4) the thin film deposition process for silicon-based dielectrics and for doped and intrinsic amorphous silicon; (5) physical properties of the thin films deposited by Remote PECVD using in-situ AES, and ex-situ infrared (ir) spectroscopy and ellipsometry; and (6) electrical performance of thin films in device structures including metal-oxide/or insulator-semiconductor (MOS or MIS) capacitors formed on silicon, and hydrogenated -amorphous silicon thin film transistors (a-Si:H TFT's). Atomically clean semiconductor surfaces are obtained by a remote hydrogen plasma treatment prior to thin film deposition. In the remote PECVD process the process gases are selectively excited, the silane reactant, the source of silicon atoms in the films is never directly plasma excited, and the substrate is also remote from the plasma discharge region. These differences between the remote PECVD process and the conventional direct PECVD process, result in improved control of the insulator stoichiometry, and a reduction in level of chemical impurities such as hydrogen. We find that the

  6. Fundamental studies of defect generation in amorphous silicon alloys grown by remote plasma-enhanced chemical-vapor deposition (Remote PECVD)

    SciTech Connect

    Lucovsky, G.; Nemanich, R.J.; Bernholc, J.; Whitten, J.; Wang, C.; Davidson, B.; Williams, M.; Lee, D.; Bjorkman, C.; Jing, Z. )

    1993-01-01

    We demonstrated that the remote PECVD process can be used to deposit heavily doped n-type and p-type a-Si:H thin films. We optimized conditions for depositing undoped, near-intrinsic and heavily doped thin films of [mu]c(microcrystalline)-Si by remote PECVD. We extended the remote PECVD process to the deposition of undoped and doped a-Si,C:H and [mu]c-Si,C alloy films. We analyzed transport data for the dark conductivity in undoped and doped a-Si:H, a-Si,C:H, [mu]c-Si and [mu]c-Si,C films. We studied the properties of doped a-Si:H and [mu]c-Si in MOS capacitors using [approximately]10 [Omega]-cm p-type crystalline substrates and thermally grown Si0[sub 2] dielectric layers. We collaborated with a group at RWTH in Aachen, Germany, and studied the contributions of process induced defect states to the recombination of photogenerated electron pairs. We applied a tight-binding model to Si-Bethe lattice structures to investigate the effects of bond angle, and dihedral angle disorder. We used ab initio and empirical calculations to study non-random bonding arrangements in a-Si,O:H and doped a-Si:H films.

  7. In situ spectroscopic ellipsometry growth studies on the Al-doped ZnO films deposited by remote plasma-enhanced metalorganic chemical vapor deposition

    SciTech Connect

    Volintiru, I.; Creatore, M.; Sanden, M. C. M. van de

    2008-02-01

    In situ spectroscopic ellipsometry (SE) was applied to study the pyramidlike and pillarlike growth of Al doped ZnO (AZO) films deposited by means of remote plasma-enhanced metalorganic chemical vapor deposition for transparent conductive oxide applications. Real time SE studies in the visible region allowed discerning between the two growth modes by addressing the time evolution of the bulk and surface roughness layer thickness. While the pillarlike mode is characterized by a constant growth rate, a slower rate in the initial stage (up to 150-200 nm film thickness), compared to the bulk, is observed for the growth of pyramidlike AZO films. The two modes differ also in terms of surface roughness development: a saturation behavior is observed for film thickness above 150-200 nm in the case of the pyramidlike films, while a slow linear increase with film thickness characterizes the pillarlike mode. By extending the SE analysis of the AZO films to the near infrared region, valuable information about the in grain properties could be extracted: excellent in grain mobility values, i.e., larger than 100 and 50 cm{sup 2}/V s, are determined for the pyramidlike and pillarlike AZO layers, respectively. The comparison between the outcome of the in situ real time SE studies and the ex situ electrical and chemical characterization highlights the limitations in the electron transport occurring in both types of films and allows one to address routes toward further improvement in AZO conductivity.

  8. Evolution of the electrical and structural properties during the growth of Al doped ZnO films by remote plasma-enhanced metalorganic chemical vapor deposition

    SciTech Connect

    Volintiru, I.; Creatore, M.; Kniknie, B. J.; Spee, C. I. M. A.; Sanden, M. C. M. van de

    2007-08-15

    Al-doped zinc oxide (AZO) films were deposited by means of remote plasma-enhanced metalorganic chemical vapor deposition from oxygen/diethylzinc/trimethylaluminum mixtures. The electrical, structural (crystallinity and morphology), and chemical properties of the deposited films were investigated using Hall, four point probe, x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), electron recoil detection (ERD), Rutherford backscattering (RBS), and time of flight secondary ion mass spectrometry (TOF-SIMS), respectively. We found that the working pressure plays an important role in controlling the sheet resistance R{sub s} and roughness development during film growth. At 1.5 mbar the AZO films are highly conductive (R{sub s}<6 {omega}/{open_square} for a film thickness above 1200 nm) and very rough (>4% of the film thickness), however, they are characterized by a large sheet resistance gradient with increasing film thickness. By decreasing the pressure from 1.5 to 0.38 mbar, the gradient is significantly reduced and the films become smoother, but the sheet resistance increases (R{sub s}{approx_equal}100 {omega}/{open_square} for a film thickness of 1000 nm). The sheet resistance gradient and the surface roughness development correlate with the grain size evolution, as determined from the AFM and SEM analyses, indicating the transition from pyramid-like at 1.5 mbar to pillar-like growth mode at 0.38 mbar. The change in plasma chemistry/growth precursors caused by the variation in pressure leads to different concentration and activation efficiency of Al dopant in the zinc oxide films. On the basis of the experimental evidence, a valid route for further improving the conductivity of the AZO film is found, i.e., increasing the grain size at the initial stage of film growth.

  9. Holographic enhanced remote sensing system

    NASA Technical Reports Server (NTRS)

    Iavecchia, Helene P.; Gaynor, Edwin S.; Huff, Lloyd; Rhodes, William T.; Rothenheber, Edward H.

    1990-01-01

    The Holographic Enhanced Remote Sensing System (HERSS) consists of three primary subsystems: (1) an Image Acquisition System (IAS); (2) a Digital Image Processing System (DIPS); and (3) a Holographic Generation System (HGS) which multiply exposes a thermoplastic recording medium with sequential 2-D depth slices that are displayed on a Spatial Light Modulator (SLM). Full-parallax holograms were successfully generated by superimposing SLM images onto the thermoplastic and photopolymer. An improved HGS configuration utilizes the phase conjugate recording configuration, the 3-SLM-stacking technique, and the photopolymer. The holographic volume size is currently limited to the physical size of the SLM. A larger-format SLM is necessary to meet the desired 6 inch holographic volume. A photopolymer with an increased photospeed is required to ultimately meet a display update rate of less than 30 seconds. It is projected that the latter two technology developments will occur in the near future. While the IAS and DIPS subsystems were unable to meet NASA goals, an alternative technology is now available to perform the IAS/DIPS functions. Specifically, a laser range scanner can be utilized to build the HGS numerical database of the objects at the remote work site.

  10. Fabrication of graphene-based films using remote plasma CVD

    NASA Astrophysics Data System (ADS)

    Hiramatsu, Mineo; Tsukada, Ryosuke; Kashima, Yohei; Naito, Masateru; Kondo, Hiroki; Hori, Masaru

    2012-10-01

    Plasma-enhanced CVD (PECVD) employing methane/hydrogen gases has been used to grow diamond, diamond-like carbon, and carbon nanotubes. In the case of microwave PECVD with methane/hydrogen system without catalyst nanoparticles at temperatures of 700--850 ^oC, where the substrate is exposed to the plasma, vertical nano-graphenes and carbon nanoflakes have been easily grown even on Cu substrate due to the ion bombardment and local electric field forces. In this work, we demonstrate the synthesis of planar few-layer graphene-based film using PECVD with remote plasma configuration. In the case using microwave plasma of cylindrical resonant cavity type, by simply installing grounded grid over the substrate plate for obtaining remote plasma configuration, we have successfully fabricated graphene-based films on Cu substrate, which was confirmed by the Raman spectrum and SEM image of deposit. Similar method will be applied to other plasmas such as low-pressure inductively coupled plasma, in order to verify the effectiveness of remote plasma configuration for the growth of planar graphene using PECVD technique. We will discuss the planar graphene growth mechanism in terms of precursors and their surface reaction.

  11. Investigations of Remote Plasma Irregularites by Radio Sounding: Applications of the Radio Plasma Imager on IMAGE

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Benson, Robert F.; Carpenter, Donald L.; Reinsch, Bodo W.; Gallagher, Dennis L.

    1999-01-01

    The Radio Plasma Imager (RPI) on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission operates like a radar by transmitting and receiving coherent electromagnetic pulses. Long-range echoes of electromagnetic sounder waves are reflected at remote plasma cutoffs. Thus, analyses of RPI observations will yield the plasma parameters and distances to the remote reflection points. These analyses assume that the reflecting plasma surfaces are cold and are sufficiently smooth that they effectively behave as plane mirrors to the incoming sounder waves, i.e., that geometric optics can be used. The RPI will employ pulse compression and spectral integration techniques, perfected in ground-based ionospheric digital sounders, in order to enhance the signal-to-noise ratio in long-range magnetospheric sounding. When plasma irregularities exist in the remote magnetospheric plasmas that are being probed by the sounder waves, echo signatures may become complicated. Ionospheric sounding experience indicates that while topside sounding echo strengths can actually be enhanced by the presence of irregularities, ground-based sounding indicates that coherent detection techniques can still be employed. In this paper we investigate the plasma conditions that will allow coherent signals to be detected by the RPI and the signatures to be expected, such as scattering and plasma resonances, in the presence of multi-scale irregularities, may possibly have on RPI signals. Sounding of irregular plasma structures in the plasmasphere, plasmapause and magnetopause are also discussed.

  12. Remote plasma enhanced chemical vapor deposition of fluorinated silicon oxide films using 1,2bis(methyldifluorosilyl)ethane and triethoxyfluorosilane

    NASA Astrophysics Data System (ADS)

    Jin, Zhongping

    2005-07-01

    The deposition characteristics of fluorinated silicon dioxide (SiO xFy) films using two fluorine-containing precursors, 1,2bis(methyldifluorosilyl)ethane (FASi-4) and triethoxyfluorosilane (FTES) were investigated in a custom-built remote microwave plasma enhanced chemical vapor deposition (PECVD) micro-reactor system. These studies were motivated by the finding that incorporation of fluorine in the oxide films reduces the dielectric permittivity of the films. Statistically-designed experiments were performed to identify significant independent parameters and their interactions, and to determine preferred operating windows; subsequent one factor at a time experiments were performed to better understand the effects of important single variables. Complementary film characterization methods including Rutherford Backscattering Spectroscopy (RBS), Fourier transform infrared transmission spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to investigate and quantify film physical, chemical and electrical properties. Arrhenius-type plots for the dependence of the deposition rate on substrate inverse temperature show that the FASi-4 sourced process is mildly activated with an apparent activation energy of 0.17 eV at a pressure of 0.4 Torr and 0.05 eV at a pressure of 0.1 Torr. Single factor experiments indicate that the deposition rates exhibit maxima at 0.1 Torr and 0.31 Torr for FASi-4 and FTES, respectively. The deposition rate maxima occur at lower pressures than the corresponding maximum observed for PETEOS deposition (˜0.6 Torr). Deposition rate maxima were also observed as a function of oxygen to source gas flow ratio. The deposition rate maximizes at 108 A/min with an oxygen: FTES flow ratio of 12:1. The deposition rate with TEOS, on the other hand, maximizes at over 400 A/min at an oxygen: TEOS flow ratio of 3:1. RBS data indicate that decreasing O2:FASi-4 ratio from 15:1 to 8:1 increases the fluorine content in the deposited fluorinated silicon

  13. Ferromagnetic enhanced inductive plasma sources

    NASA Astrophysics Data System (ADS)

    Godyak, Valery

    2013-07-01

    The subject of this paper is the review of inductively coupled plasma (ICP) sources enhanced with ferromagnetic cores, FMICP, found in various applications, including plasma fusion, space propulsion, light sources, plasma chemistry and plasma processing of materials. The history of FMICP, early attempts for their realization, some recent developments and examples of successful FMICP devices are given here. A comparative study of FMICPs with conventional ICPs demonstrates their certain advantages in power transfer efficiency, power factor and their ability to operate without rf plasma potentials at low plasma densities and with small gaps, while effectively controlling plasma density profile.

  14. Flood Management Enhancement Using Remotely Sensed Data

    NASA Technical Reports Server (NTRS)

    Romanowski, Gregory J.

    1997-01-01

    SENTAR, Inc., entered into a cooperative agreement with NASA Goddard Space Flight Center (GSFC) in December 1994. The intent of the NASA Cooperative Agreement was to stimulate broad public use, via the Internet, of the very large remote sensing databases maintained by NASA and other agencies, thus stimulating U.S. economic growth, improving the quality of life, and contributing to the implementation of a National Information Infrastructure. SENTAR headed a team of collaborating organizations in meeting the goals of this project. SENTAR's teammates were the NASA Marshall Space Flight Center (MSFC) Global Hydrology and Climate Center (GHCC), the U.S. Army Space and Strategic Defense Command (USASSDC), and the Alabama Emergency Management Agency (EMA). For this cooperative agreement, SENTAR and its teammates accessed remotely sensed data in the Distributed Active Archive Centers, and other available sources, for use in enhancing the present capabilities for flood disaster management by the Alabama EMA. The project developed a prototype software system for addressing prediction, warning, and damage assessment for floods, though it currently focuses on assessment. The objectives of the prototype system were to demonstrate the added value of remote sensing data for emergency management operations during floods and the ability of the Internet to provide the primary communications medium for the system. To help achieve these objectives, SENTAR developed an integrated interface for the emergency operations staff to simplify acquiring and manipulating source data and data products for use in generating new data products. The prototype system establishes a systems infrastructure designed to expand to include future flood-related data and models or to include other disasters with their associated remote sensing data requirements and distributed data sources. This report covers the specific work performed during the seventh, and final, milestone period of the project, which

  15. Interactive computer-enhanced remote viewing system

    SciTech Connect

    Tourtellott, J.A.; Wagner, J.F.

    1995-10-01

    Remediation activities such as decontamination and decommissioning (D&D) typically involve materials and activities hazardous to humans. Robots are an attractive way to conduct such remediation, but for efficiency they need a good three-dimensional (3-D) computer model of the task space where they are to function. This model can be created from engineering plans and architectural drawings and from empirical data gathered by various sensors at the site. The model is used to plan robotic tasks and verify that selected paths are clear of obstacles. This report describes the development of an Interactive Computer-Enhanced Remote Viewing System (ICERVS), a software system to provide a reliable geometric description of a robotic task space, and enable robotic remediation to be conducted more effectively and more economically.

  16. Fundamental studies of defect generation in amorphous silicon alloys grown by remote plasma-enhanced chemical-vapor deposition. Final subcontract report, 1 July 1989--31 December 1992

    SciTech Connect

    Lucovsky, G.

    1993-08-01

    This report describes research to reduce the intrinsic bonding defects in amorphous and microcrystalline Si alloys by controlling the bonding chemistry and the microstructure via the deposition process reactions. The specific approach was to use remote plasma-enhanced, chemical-vapor deposition (PECVD) and reactive magnetron sputtering to limit the multiplicity of deposition inaction pathways, and thereby gain increased control over the thin-film chemistry and microstrucre. The research included (1) the deposition of amorphous and microcrystalline Si alloy materials by the PECVD process and by reactive magnetron sputtering, and (2) the evaluation of the material properties of these films for potential applications in PV devices. The focus of the research was on pining a fundamental understanding of the relationships between deposition reaction pathways, the bonding of dopant and alloy atoms, and the electrical provides of importance for PV applications. This involved studying the factors that contribute to defect generation and to defect removal and/or neutralization. In addition to the experimental studies, the research also included theoretical and modeling studies aimed at understanding the relationships between local atomic arrangements of Si and alloy atoms, and the electrical, optical, vibrational, and defect properties.

  17. Fundamental studies of defect generation in amorphous silicon alloys grown by remote plasma-enhanced chemical-vapor deposition (Remote PECVD). Annual subcontract report, 1 September 1990--31 August 1991

    SciTech Connect

    Lucovsky, G.; Nemanich, R.J.; Bernholc, J.; Whitten, J.; Wang, C.; Davidson, B.; Williams, M.; Lee, D.; Bjorkman, C.; Jing, Z.

    1993-01-01

    We demonstrated that the remote PECVD process can be used to deposit heavily doped n-type and p-type a-Si:H thin films. We optimized conditions for depositing undoped, near-intrinsic and heavily doped thin films of {mu}c(microcrystalline)-Si by remote PECVD. We extended the remote PECVD process to the deposition of undoped and doped a-Si,C:H and {mu}c-Si,C alloy films. We analyzed transport data for the dark conductivity in undoped and doped a-Si:H, a-Si,C:H, {mu}c-Si and {mu}c-Si,C films. We studied the properties of doped a-Si:H and {mu}c-Si in MOS capacitors using {approximately}10 {Omega}-cm p-type crystalline substrates and thermally grown Si0{sub 2} dielectric layers. We collaborated with a group at RWTH in Aachen, Germany, and studied the contributions of process induced defect states to the recombination of photogenerated electron pairs. We applied a tight-binding model to Si-Bethe lattice structures to investigate the effects of bond angle, and dihedral angle disorder. We used ab initio and empirical calculations to study non-random bonding arrangements in a-Si,O:H and doped a-Si:H films.

  18. Interactive computer-enhanced remote viewing system

    SciTech Connect

    Tourtellott, J.A.; Wagner, J.F.

    1995-12-01

    Remediation activities such as decontamination and decommissioning (D&D) typically involve materials and activities hazardous to humans. Robots are an attractive way to conduct such remediation, but for efficiency they need a good three-dimensional (3-D) computer model of the task space where they are to function. This model can be created from engineering plans and architectural drawings and from empirical data gathered by various sensors at the site. The model is used to plan robotic tasks and verify that selected paths am clear of obstacles. This need for a task space model is most pronounced in the remediation of obsolete production facilities and underground storage tanks. Production facilities at many sites contain compact process machinery and systems that were used to produce weapons grade material. For many such systems, a complex maze of pipes (with potentially dangerous contents) must be removed, and this represents a significant D&D challenge. In an analogous way, the underground storage tanks at sites such as Hanford represent a challenge because of their limited entry and the tumbled profusion of in-tank hardware. In response to this need, the Interactive Computer-Enhanced Remote Viewing System (ICERVS) is being designed as a software system to: (1) Provide a reliable geometric description of a robotic task space, and (2) Enable robotic remediation to be conducted more effectively and more economically than with available techniques. A system such as ICERVS is needed because of the problems discussed below.

  19. Feedback enhanced plasma spray tool

    DOEpatents

    Gevelber, Michael Alan; Wroblewski, Donald Edward; Fincke, James Russell; Swank, William David; Haggard, Delon C.; Bewley, Randy Lee

    2005-11-22

    An improved automatic feedback control scheme enhances plasma spraying of powdered material through reduction of process variability and providing better ability to engineer coating structure. The present inventors discovered that controlling centroid position of the spatial distribution along with other output parameters, such as particle temperature, particle velocity, and molten mass flux rate, vastly increases control over the sprayed coating structure, including vertical and horizontal cracks, voids, and porosity. It also allows improved control over graded layers or compositionally varying layers of material, reduces variations, including variation in coating thickness, and allows increasing deposition rate. Various measurement and system control schemes are provided.

  20. Visualization of Remotely-Sensed Heliospheric Plasmas

    NASA Astrophysics Data System (ADS)

    Bailey, M.; Hick, P. P.; Wang, C.; Jackson, B. V.; Buffington, A.

    2002-12-01

    We demonstrate a software application designed for the display and real-time manipulation of 3D heliospheric volume data, such as solar wind density, velocity and magnetic field. The software exploits the capabilities of the Volume Pro 1000 (from TeraRecon, Inc.), a low-cost 64-bit PCI board capable of rendering a 512-cubed array of volume data in real time at up to 30 frames per second on a standard PC. The application allows stereo and perspective views, and animations of time-sequences. We show several examples of three-dimensional heliospheric volume data derived from tomographic reconstructions based on heliospheric remote sensing observations of the heliospheric density and velocity structure (e.g. Thomson scattering and interplanetary scintillation observations). This work was supported through NASA grant NAG5-9423 and Air Force MURI grant F49620-01-0359.

  1. Optical vs. electronic enhancement of remote sensing imagery

    NASA Technical Reports Server (NTRS)

    Colwell, R. N.; Katibah, E. F.

    1976-01-01

    Basic aspects of remote sensing are considered and a description is provided of the methods which are employed in connection with the optical or electronic enhancement of remote sensing imagery. The advantages and limitations of various image enhancement methods and techniques are evaluated. It is pointed out that optical enhancement methods and techniques are currently superior to electronic ones with respect to spatial resolution and equipment cost considerations. Advantages of electronic procedures, on the other hand, are related to a greater flexibility regarding the presentation of the information as an aid for the interpretation by the image analyst.

  2. Enhancing the Remote Variable Operations in NPSS/CCDK

    NASA Technical Reports Server (NTRS)

    Sang, Janche; Follen, Gregory; Kim, Chan; Lopez, Isaac; Townsend, Scott

    2001-01-01

    Many scientific applications in aerodynamics and solid mechanics are written in Fortran. Refitting these legacy Fortran codes with distributed objects can increase the code reusability. The remote variable scheme provided in NPSS/CCDK helps programmers easily migrate the Fortran codes towards a client-server platform. This scheme gives the client the capability of accessing the variables at the server site. In this paper, we review and enhance the remote variable scheme by using the operator overloading features in C++. The enhancement enables NPSS programmers to use remote variables in much the same way as traditional variables. The remote variable scheme adopts the lazy update approach and the prefetch method. The design strategies and implementation techniques are described in details. Preliminary performance evaluation shows that communication overhead can be greatly reduced.

  3. Comparison of Plasma Activation of Thin Water Layers by Direct and Remote Plasma Sources

    NASA Astrophysics Data System (ADS)

    Kushner, Mark

    2014-10-01

    Plasma activation of liquids is now being investigated for a variety of biomedical applications. The plasma sources used for this activation can be generally classified as direct (the plasma is in contact with the surface of the liquid) or remote (the plasma does not directly touch the liquid). The direct plasma source may be a dielectric barrier discharge (DBD) where the surface of the liquid is a floating electrode or a plasma jet in which the ionization wave forming the plasma plume reaches the liquid. The remote plasma source may be a DBD with electrodes electrically isolated from the liquid or a plasma jet in which the ionization wave in the plume does not reach the liquid. In this paper, a comparison of activation of thin water layers on top of tissue, as might be encountered in wound healing, will be discussed using results from numerical investigations. We used the modeling platform nonPDPSIM to simulate direct plasma activation of thin water layers using DBDs and remote activation using plasma jets using up to hundreds of pulses. The DBDs are sustained in humid air while the plasma jets consist of He/O2 mixtures flowed into humid air. For similar number of pulses and energy deposition, the direct DBD plasma sources produce more acidification and higher production of nitrates/nitrites in the liquid. This is due to the accumulation of NxOy plasma jets, the convective flow removes many of these species prior to their diffusing into the water or reacting to form higher nitrogen oxides. This latter effect is sensitive to the repetition rate which determines whether reactive species formed during prior pulses overlap with newly produced reactive species. in the gas phase. In the plasma jets, the convective flow removes many of these species prior to their diffusing into the water or reacting to form higher nitrogen oxides. This latter effect is sensitive to the repetition rate which determines whether reactive species formed during prior pulses overlap with

  4. Sunrise enhancement of equatorial vertical plasma drift

    NASA Astrophysics Data System (ADS)

    Liu, Libo; Zhang, Ruilong; Le, Huijun

    2016-04-01

    Sunrise enhancement in vertical plasma drift over equatorial regions is not discernible in the statistical picture compared with the significant enhancement during dusk hours. In this report, it is the first time to investigate the occurrence of the dawn enhancement in the equatorial ionospheric vertical plasma drift from ROCSAT-1 observations during geomagnetic quiet times. The dawn enhancements occur most frequently in June solstice and least frequently in December solstice. The statistical survey shows that the occurrence depends on the magnetic declination. The enhancement has the strongest amplitude in regions near 320° longitude and peaks during June solstice. The dawn enhancement reaches its peak after the sunrise in conjugated E regions. Furthermore, it is found that the dawn enhancement is closely related to the difference between the sunrise times in the conjugated E regions (sunrise time lag). The dawn enhancement occurs easily in regions with a large sunrise time lag. Moreover, we will report the effects of the sunrise enhancement of vertical plasma drift on the equatorial ionosphere as indicated from the observations and model simulations. We thanks National Central University of Taiwan providing the ROCSAT-1 data. The Ap and F107 indices are obtained from the National Geophysical Data Center (http://spidr.ngdc.noaa.gov/spidr/). This research is supported by National Natural Science Foundation of China (41231065), the Chinese Academy of Sciences project (KZZD-EW-01-3), National Key Basic Research Program of China (2012CB825604) and National Natural Science Foundation of China (41321003).

  5. Remote Ischemic Preconditioning (RIPC) Modifies Plasma Proteome in Humans

    PubMed Central

    Hepponstall, Michele; Ignjatovic, Vera; Binos, Steve; Monagle, Paul; Jones, Bryn; Cheung, Michael H. H.; d’Udekem, Yves; Konstantinov, Igor E.

    2012-01-01

    Remote Ischemic Preconditioning (RIPC) induced by brief episodes of ischemia of the limb protects against multi-organ damage by ischemia-reperfusion (IR). Although it has been demonstrated that RIPC affects gene expression, the proteomic response to RIPC has not been determined. This study aimed to examine RIPC induced changes in the plasma proteome. Five healthy adult volunteers had 4 cycles of 5 min ischemia alternating with 5 min reperfusion of the forearm. Blood samples were taken from the ipsilateral arm prior to first ischaemia, immediately after each episode of ischemia as well as, at 15 min and 24 h after the last episode of ischemia. Plasma samples from five individuals were analysed using two complementary techniques. Individual samples were analysed using 2Dimensional Difference in gel electrophoresis (2D DIGE) and mass spectrometry (MS). Pooled samples for each of the time-points underwent trypsin digestion and peptides generated were analysed in triplicate using Liquid Chromatography and MS (LC-MS). Six proteins changed in response to RIPC using 2D DIGE analysis, while 48 proteins were found to be differentially regulated using LC-MS. The proteins of interest were involved in acute phase response signalling, and physiological molecular and cellular functions. The RIPC stimulus modifies the plasma protein content in blood taken from the ischemic arm in a cumulative fashion and evokes a proteomic response in peripheral blood. PMID:23139772

  6. Remote limb ischemic conditioning enhances motor learning in healthy humans.

    PubMed

    Cherry-Allen, Kendra M; Gidday, Jeff M; Lee, Jin-Moo; Hershey, Tamara; Lang, Catherine E

    2015-06-01

    Brief bouts of sublethal ischemia have been shown to protect exposed tissue (ischemic conditioning) and tissues at remote sites (remote ischemic conditioning) against subsequent ischemic challenges. Given that the mechanisms of this protective phenomenon are multifactorial and epigenetic, we postulated that remote limb ischemic conditioning (RLIC) might enhance mechanisms responsible for neural plasticity, and thereby facilitate learning. Specifically, we hypothesized that conditioning of the nervous system with RLIC, achieved through brief repetitive limb ischemia prior to training, would facilitate the neurophysiological processes of learning, thus making training more effective and more long-lasting. Eighteen healthy adults participated in this study; nine were randomly allocated to RLIC and nine to sham conditioning. All subjects underwent seven consecutive weekday sessions and 2-wk and 4-wk follow-up sessions. We found that RLIC resulted in significantly greater motor learning and longer retention of motor performance gains in healthy adults. Changes in motor performance do not appear to be due to a generalized increase in muscle activation or muscle strength and were not associated with changes in serum brain-derived neurotrophic factor (BDNF) concentration. Of note, RLIC did not enhance cognitive learning on a hippocampus-dependent task. While future research is needed to establish optimal conditioning and training parameters, this inexpensive, clinically feasible paradigm might ultimately be implemented to enhance motor learning in individuals undergoing neuromuscular rehabilitation for brain injury and other pathological conditions. PMID:25867743

  7. Remote limb ischemic conditioning enhances motor learning in healthy humans

    PubMed Central

    Cherry-Allen, Kendra M.; Gidday, Jeff M.; Lee, Jin-Moo; Hershey, Tamara

    2015-01-01

    Brief bouts of sublethal ischemia have been shown to protect exposed tissue (ischemic conditioning) and tissues at remote sites (remote ischemic conditioning) against subsequent ischemic challenges. Given that the mechanisms of this protective phenomenon are multifactorial and epigenetic, we postulated that remote limb ischemic conditioning (RLIC) might enhance mechanisms responsible for neural plasticity, and thereby facilitate learning. Specifically, we hypothesized that conditioning of the nervous system with RLIC, achieved through brief repetitive limb ischemia prior to training, would facilitate the neurophysiological processes of learning, thus making training more effective and more long-lasting. Eighteen healthy adults participated in this study; nine were randomly allocated to RLIC and nine to sham conditioning. All subjects underwent seven consecutive weekday sessions and 2-wk and 4-wk follow-up sessions. We found that RLIC resulted in significantly greater motor learning and longer retention of motor performance gains in healthy adults. Changes in motor performance do not appear to be due to a generalized increase in muscle activation or muscle strength and were not associated with changes in serum brain-derived neurotrophic factor (BDNF) concentration. Of note, RLIC did not enhance cognitive learning on a hippocampus-dependent task. While future research is needed to establish optimal conditioning and training parameters, this inexpensive, clinically feasible paradigm might ultimately be implemented to enhance motor learning in individuals undergoing neuromuscular rehabilitation for brain injury and other pathological conditions. PMID:25867743

  8. Plasma cell adaptation to enhance particle acceleration

    SciTech Connect

    Ragheb, M. S.

    2008-06-15

    A plasma study is performed in order to construct a cell for plasma acceleration purpose. As well, a multicell design is introduced for the injection of beam driver application. The suggested idea is experimentally demonstrated for two plasma cell configuration. The preformed plasma is obtained by a symmetrically driven capacitive audio frequency discharge. It is featured by its moderate pressure of 0.1-0.2 Torr, low consumption power of 130 W maximum, low discharge voltage and frequency up to 950 V and 20 kHz, respectively, and high plasma density from 10{sup 11} to 10{sup 15} cm{sup -3}. The electron temperature obtained by Langmuir double probe varies from 1 up to 16 eV. It is observed that the increases of the discharge voltage and frequency enlarge the plasma parameters to their maximum values. The plasma cell filled with different gases demonstrates that the Ar and He gases manifest the highest ionization efficiency exceeding 100% at 950 V and 20 kHz. The formed plasma is cold; its density is uniform and stable along the positive column for long competitive lifetime. Showing that it follows the conditions to enhance particle acceleration and in conjunction with its periphery devices form a plasma cell that could be extended to serve this purpose. Demonstrating that an injected electron beam into the extended preformed plasma could follow, to long distance, a continuous trajectory of uniform density. Such plasma generated by H{sub 2} or Ar gases is suggested to be used, respectively, for low-density or higher density beam driver.

  9. Chrome and Zinc Contaminants Removal from Silicon (100) Surfaces by Remote Plasma Cleaning Techniques

    NASA Astrophysics Data System (ADS)

    Lee, Seungwook; Lee, Jaegab; Lee, Chongmu

    2001-06-01

    Removal of Cr and Zn impurities on Si surfaces using remote plasma H2 was investigated. Si surfaces were contaminated intentionally with low-purity acetone. To determine the optimum process conditions, remote plasma H2 cleaning was conducted for various rf powers and plasma exposure times. After remote plasma H2 cleaning, Si surfaces were analyzed by total X-ray reflection fluorescence (TXRF), surface photovoltage (SPV) and atomic force microscopy (AFM). The concentrations of Cr and Zn impurities were reduced by more than a factor of 2 and the minority carrier lifetime increased. Also the root-mean-square (RMS) roughness decreased by more than 30% after the remote plasma H2 cleaning. TXRF analysis results show that remote plasma H2 cleaning is effective in eliminating Cr and Zn impurities from the Si surface only if it is performed under optimum process conditions. AFM analysis results also show that remote plasma H2 cleaning causes no damage to the Si surface. Cr and Zn impurities on the Si substrate are considered to be contaminated as forms of hydroxides, silioxides and oxides on chemical oxides formed during intentional chemical contamination. The removal mechanism of Cr and Zn impurities using remote plasma H2 treatments is proposed for the lift-off during the removal of underlying chemical oxides.

  10. Enhanced betatron radiation in strongly magnetized plasma

    NASA Astrophysics Data System (ADS)

    Pan, K. Q.; Zheng, C. Y.; Cao, L. H.; Liu, Z. J.; He, X. T.

    2016-04-01

    Betatron radiation in strongly magnetized plasma is investigated by two dimensional (2D) particle-in-cell (PIC) simulations. The results show that the betatron radiation in magnetized plasmas is strongly enhanced and is more collimated compared to that in unmagnetized plasma. Single particle model analysis shows that the frequency and the amplitude of the electrons's betatron oscillation are strongly influenced by the axial external magnetic field and the axial self-generated magnetic field. And the 2D PIC simulation shows that the axial magnetic field is actually induced by the external magnetic field and tends to increase the betatron frequency. By disturbing the perturbation of the plasma density in the laser-produced channel, the hosing instability is also suppressed, which results in a better angular distribution and a better symmetry of the betatron radiation.

  11. Surface-enhanced Raman fiberoptic sensors for remote monitoring

    SciTech Connect

    Stokes, D.L.; Alarie, J.P.; Vo-Dinh, T.

    1995-09-01

    A new sensor design for remote surface-enhanced Raman scattering (SERS) measurements has been developed for environmental applications. The design features the modification of an optical fiber using layers of alumina microparticles and silver coatings for inducing the SERS effect at the sensing probe. A single fiber carries both the laser excitation and the SERS signal radiation, keeping optical parameters at the remote tip simple and consistent. The small tip size achievable with this configuration also demonstrates potential of this new design as a microsensor for in-situ measurement in microenvironments. Details of sensor tip fabrication and optical system design are described. SERS spectra of aqueous environmental samples acquired in-situ using the SERS sensor are also presented to illustrate the effectiveness of the SERS sensor.

  12. Enhanced networked server management with random remote backups

    NASA Astrophysics Data System (ADS)

    Kim, Song-Kyoo

    2003-08-01

    In this paper, the model is focused on available server management in network environments. The (remote) backup servers are hooked up by VPN (Virtual Private Network) and replace broken main severs immediately. A virtual private network (VPN) is a way to use a public network infrastructure and hooks up long-distance servers within a single network infrastructure. The servers can be represent as "machines" and then the system deals with main unreliable and random auxiliary spare (remote backup) machines. When the system performs a mandatory routine maintenance, auxiliary machines are being used for backups during idle periods. Unlike other existing models, the availability of auxiliary machines is changed for each activation in this enhanced model. Analytically tractable results are obtained by using several mathematical techniques and the results are demonstrated in the framework of optimized networked server allocation problems.

  13. Effects of Ar plasma treatment for deposition of ruthenium film by remote plasma atomic layer deposition

    SciTech Connect

    Park, Taeyong; Lee, Jaesang; Park, Jingyu; Jeon, Heeyoung; Jeon, Hyeongtag; Lee, Ki-Hoon; Cho, Byung-Chul; Kim, Moo-Sung; Ahn, Heui-Bok

    2012-01-15

    Ruthenium thin films were deposited on argon plasma-treated SiO{sub 2} and untreated SiO{sub 2} substrates by remote plasma atomic layer deposition using bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp){sub 2}] as a Ru precursor and ammonia plasma as a reactant. The results of in situ Auger electron spectroscopy (AES) analysis indicate that the initial transient region of Ru deposition was decreased by Ar plasma treatment at 400 deg. C, but did not change significantly at 300 deg. C The deposition rate exhibited linearity after continuous film formation and the deposition rates were about 1.7 A/cycle and 0.4 A/cycle at 400 deg. C and 300 deg. C, respectively. Changes of surface energy and polar and dispersive components were measured by the sessile drop test. The quantity of surface amine groups was measured from the surface nitrogen concentration with AES. Furthermore, the Ar plasma-treated SiO{sub 2} contained more amine groups and less hydroxyl groups on the surface than on untreated SiO{sub 2}. Auger spectra exhibited chemical shifts by Ru-O bonding, and larger shifts were observed on untreated substrates due to the strong adhesion of Ru films.

  14. The Physics of Remotely-Sensed Heliospheric Plasmas

    NASA Astrophysics Data System (ADS)

    Jackson, Bernard V.

    1997-08-01

    Solar disturbances produce major effects on the corona, the solar wind, the interplanetary medium, and the Earth along with its magnetosphere. New techniques have been developed under this grant for studying plasma disturbances in the inner heliosphere by remotely sensing them. These techniques have used data from the HELIOS spacecraft zodiacal light photometers, in situ data and a variety of other spacecraft and ground based instruments. The zodiacal light photometers on board the two HELIOS spacecraft (data coverage from 1974 to 1986) provided the first reliable information about the heliospheric masses and shapes of propagating disturbances. The investigations into the physics of the disturbances sensed by these techniques, and the ability to forecast them, have been underway during the contract. The data analyses have used YOHKOH spacecraft observations, Sacramento Peak Observatory and Mauna Loa (Mark 3) coronagraph data to map solar surface features. In addition, interplanetary scintillation (IPS) data from the Cambridge, England, Nagoya, Japan, and Ooty, India radio telescopes plus ULYSSES and IMP in situ data have been used to determine present day conditions in the solar wind.

  15. Neoclassical transport in enhanced confinement toroidal plasmas

    SciTech Connect

    Lin, Z.; Tang, W.M.; Lee, W.W.

    1996-11-01

    It has recently been reported that ion thermal transport levels in enhanced confinement tokamak plasmas have been observed to fall below the irreducible minimum level predicted by standard neoclassical theory. This apparent contradiction is resolved in the present analysis by relaxing the basic neoclassical assumption that the ions orbital excursions are much smaller than the local toroidal minor radius and the equilibrium scale lengths of the system.

  16. Enhancing fieldwork learning using blended learning, GIS and remote supervision

    NASA Astrophysics Data System (ADS)

    Marra, Wouter A.; Alberti, Koko; Karssenberg, Derek

    2015-04-01

    Fieldwork is an important part of education in geosciences and essential to put theoretical knowledge into an authentic context. Fieldwork as teaching tool can take place in various forms, such as field-tutorial, excursion, or supervised research. Current challenges with fieldwork in education are to incorporate state-of-the art methods for digital data collection, on-site GIS-analysis and providing high-quality feedback to large groups of students in the field. We present a case on first-year earth-sciences fieldwork with approximately 80 students in the French Alps focused on geological and geomorphological mapping. Here, students work in couples and each couple maps their own fieldwork area to reconstruct the formative history. We present several major improvements for this fieldwork using a blended-learning approach, relying on open source software only. An important enhancement to the French Alps fieldwork is improving students' preparation. In a GIS environment, students explore their fieldwork areas using existing remote sensing data, a digital elevation model and derivatives to formulate testable hypotheses before the actual fieldwork. The advantage of this is that the students already know their area when arriving in the field, have started to apply the empirical cycle prior to their field visit, and are therefore eager to investigate their own research questions. During the fieldwork, students store and analyze their field observations in the same GIS environment. This enables them to get a better overview of their own collected data, and to integrate existing data sources also used in the preparation phase. This results in a quicker and enhanced understanding by the students. To enable remote access to observational data collected by students, the students synchronize their data daily with a webserver running a web map application. Supervisors can review students' progress remotely, examine and evaluate their observations in a GIS, and provide

  17. Remote plasma-assisted deposition of metals onto the surface of nanocrystalline ZnO

    NASA Astrophysics Data System (ADS)

    Leal, Sergio A.; Nemashkalo, Anastasiia; Chapagain, Puskar; Pant, Shreedhar; Alarcon, Phillip; Strzhemechny, Yuri M.

    2011-10-01

    Controllable surface modification of nanoscale ZnO is crucial for many existing and future applications. We investigated the effectiveness of metal deposition using remote O2/He plasma passing through a metal mesh electrode onto the surface of ZnO nanopowders with an average grain size of 25 nm. Surface stoichiometry was monitored in situ with Auger electron spectroscopy, whereas surface optoelectronic properties were probed; also in situ, using surface photovoltage (SPV) spectroscopy. We observed a strong dependence of surface modification on the distance from the metal electrode. At short distances the metal coverage was reaching tens of percent of one monolayer. Simultaneously we observed a significant improvement of the SPV response pointing to metal-enhanced surface charge dynamics.

  18. A comparative study of remote plasma sources for environmentally-friendly CVD chambers cleaning

    SciTech Connect

    Raoux, S.; Lai, K.C.; Nguyen, H.; Sarfaty, M.; Li, S.T.; Davidow, J.; Huang, T.F.

    1999-07-01

    CVD chamber cleaning is the main source of perfluorocompound (PFC) emission from semiconductor fabrication plants. Over the past years, several attempts have been made to optimize chamber cleaning efficiency and reduce its environmental impact. A new cleaning technology has been introduced that improves the overall tool productivity while virtually eliminating PFC emission concerns. A remote high-density plasma source dissociates NF{sub 3} molecules, and the reactive byproducts are injected in the CVD chamber to etch the deposition residues. Due to near-complete utilization of the source gas, the technology provides reduced clean time, and the MMTCE (Million Metric Ton Carbon Equivalent) of the process can be reduced by two orders of magnitude, compared to classical in-situ RF plasma cleans. In this study, the authors compare the characteristics of a microwave-driven and a magnetically-enhanced indicatively coupled NF{sub 3} discharge. Optical Emission Spectroscopy. Quadrupole Mass Spectroscopy, Fourier Transform Infra Red and etch rate measurements were used to characterize the different sources and assess the environmental impact of the clean processes. A comparative analysis of the two types of plasma sources is made with respect to implementation of this cleaning technology in an industrial environment.

  19. Physics-electrical hybrid model for real time impedance matching and remote plasma characterization in RF plasma sources.

    PubMed

    Sudhir, Dass; Bandyopadhyay, M; Chakraborty, A

    2016-02-01

    Plasma characterization and impedance matching are an integral part of any radio frequency (RF) based plasma source. In long pulse operation, particularly in high power operation where plasma load may vary due to different reasons (e.g. pressure and power), online tuning of impedance matching circuit and remote plasma density estimation are very useful. In some cases, due to remote interfaces, radio activation and, due to maintenance issues, power probes are not allowed to be incorporated in the ion source design for plasma characterization. Therefore, for characterization and impedance matching, more remote schemes are envisaged. Two such schemes by the same authors are suggested in these regards, which are based on air core transformer model of inductive coupled plasma (ICP) [M. Bandyopadhyay et al., Nucl. Fusion 55, 033017 (2015); D. Sudhir et al., Rev. Sci. Instrum. 85, 013510 (2014)]. However, the influence of the RF field interaction with the plasma to determine its impedance, a physics code HELIC [D. Arnush, Phys. Plasmas 7, 3042 (2000)] is coupled with the transformer model. This model can be useful for both types of RF sources, i.e., ICP and helicon sources. PMID:26932040

  20. Enhancing and expanding remote photonic entanglement via local filtering operations

    NASA Astrophysics Data System (ADS)

    Xing, Hai-Bo; Yang, Ming; Dong, Ping; Fang, Shu-Dong; Cao, Zhuo-Liang

    2014-06-01

    We present an entanglement distillation scheme for enhancing remote two-photon polarization entanglement of mixed states. Although the main idea of the current scheme is based on Gisin's work (Phys. Lett. A 210 (1996) 151 [21]), there are new advantages in our new scheme, which are guaranteed by the nondemolition measurement of photonic state and the re-distillation of the garbage states. This entanglement distillation scheme not only can enhance the remote entanglement of mixed states, but also can expand two-photon entangled states to four-photon entangled states. So this scheme is an apparently feasible way for preparing multi-photon entangled states. The main idea is based on the principle of the cross-Kerr nonlinearity and the parity-check measurements (a nondemolition measurement) on photonic states. Two distant users Alice and Bob first start with one shared but less entangled photon pair, and with the help of local auxiliary photons, parity-check measurements and classical communication they can get a four-photon highly entangled states with a high success probability. For the fail result, although the garbage state is less entangled than the initial one, there is still entanglement in it. So these garbage states can be re-collected and distilled again instead of being discarded. In this sense, we can see that this protocol has a high yield, and the fidelity (with respect to the Bell state) of the initial state is not required to be bigger than 1/2 (a common threshold of the standard entanglement purification theory). In addition, post-selection measurements on the entangled photons are not needed here because of the nondemolition measurement. The nondemolition character of the measurement allows further processing of the resulting states. These advantages make the current scheme more feasible within the current technology.

  1. Controlled Nitrogen Atom Incorporation at Silicon - Dioxide Interfaces by a New, Low-Temperature Remote Plasma Process

    NASA Astrophysics Data System (ADS)

    Lee, David Roger

    1995-01-01

    A new, low-temperature (300^circ C), remote plasma process has been developed for incorporating controlled amounts of N-atoms at Si-SiO _2 interfaces and has been shown to improve the quality and reliability of Metal-Oxide-Semiconductor (MOS) devices. The process involves exposing an ex-situ cleaned wafer to species from a remote N_2 O plasma as a prelude to Remote Plasma Enhanced Chemical Vapor Deposition (Remote PECVD) of gate-quality SiO_2 films. Auger Electron Spectroscopy (AES) studies and Secondary Ion Mass Spectrometry (SIMS) depth profiles have been used to investigate the chemical nature of the Si-SiO_2 interface formed by this new technique. The results indicate that this pre-deposition process (1) removed residual carbon to ~10^{12 } C-atoms/cm^2, (2) resulted in the remote plasma-assisted growth of ~0.5 nm of SiO_2, and (3) incorporated controllably between 10^ {14}-10^{15} N-atoms/cm^2 at the Si-SiO _2 interface. Optical Second Harmonic Generation (SHG) spectroscopy has shown that the N-atoms are bonded to Si-atoms at the Si-SiO_2 interface and relieve chemical strain in adjacent Si-Si bonds relative to the case where only O-atoms are bonded at the interface. This N_2O remote plasma, predeposition oxidation process was used in a cluster tool manufacturing test bed for the fabrication of MOS capacitors and Field-Effect Transistors (FETs). Remote PECVD oxides with and without nitrided interfaces were compared, and N-atom incorporation by this technique was found to improve the drive current and high-field electron mobility of n -MOSFETs while not adversely affecting the threshold voltage, V_{rm t}, or peak channel transconductance, g_{rm m}, of the devices. N-atom incorporation also suppressed hot-carrier damage in the gate dielectric of sub-micron (effective channel length ~ 0.64 μm) n-MOSFETs. In particular, peak g_{rm m}, V _{rm t}, and the slope of the subthreshold current are all degraded less with increasing N-atom concentrations at the Si-SiO _2

  2. Multiple pulse resonantly enhanced laser plasma wakefield acceleration

    SciTech Connect

    Corner, L.; Walczak, R.; Nevay, L. J.; Dann, S.; Hooker, S. M.; Bourgeois, N.; Cowley, J.

    2012-12-21

    We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates.

  3. Enhanced Geometric Metadata for Cassini Optical Remote Sensing Instruments

    NASA Astrophysics Data System (ADS)

    Gordon, Mitchell K.; Showalter, M. R.; Wells, B.; Ballard, L.; Heather, N.

    2012-10-01

    In the past few years, the PDS Rings Node developed the Outer Planets Unified Search (OPUS), along with preview images or footprint diagrams for all OPUS supported data, and enhanced geometric metadata for Cassini ISS Saturn system data. Typically, geometric metadata for outer planets remote sensing observations is available only for the center of the instrument field of view. In our first effort at generating enhanced metadata, we calculated values for a fine grid of points over the entire field of view of Cassini ISS images using the most current SPICE kernel files. That project produce enhanced metadata specific to the rings; consequently the metadata was tied to the ring plane of Saturn. The combination of OPUS and the data base of enhanced geometric metadata provided a powerful, well received tool, and resulted in additional funding to extend metadata generation. We are developing a set of tools to produce geometric metadata for Cassini ISS, VIMS, UVIS, and CIRS Saturn data. This metadata will not be restricted to ring plane calculations and will support searches based on latitude and longitude for the planet and satellites as well as parameters such as viewing and illumination geometry. We also identify all known bodies and rings in the field of view, so target based search results will be comprehensive rather providing a subset based on the designated primary target. This autumn we have begun the incremental inclusion of the new metadata in the OPUS data base. In a subsequent phase we intend to expand our web services to include on-the-fly production of user selected geometric backplanes for each product returned by OPUS. http://pds-rings.seti.org/search/ Acknowledgments: This development has been supported by the Planetary Data System, by JPL through a special grant from the Cassini Project, and by research grants from STScI and NASA.

  4. The enhancement mechanism of thin plasma layer on antenna radiation

    SciTech Connect

    Wang, Chunsheng Jiang, Binhao; Li, Xueai

    2015-03-09

    A model of plasma-antenna is carried out to study the radiation enhancement mechanism of antenna covered by thin plasma layer. The results show when the radiation intensity achieves maximum, a region of equal electric field is formed due to the reflection of electric field at the interface of plasma and air. The plasma layer acted as an extension of the antenna. Furthermore, the shape of plasma layer is changed to verify the effect of plasma boundary on antenna radiation. The study shows the effect of thin plasma layer on electromagnetic field and provides a type of plasma antenna.

  5. Enhanced line emission from laser-produced plasmas

    NASA Technical Reports Server (NTRS)

    Timmer, C.; Srivastava, S. K.; Hall, T. E.; Fucaloro, A. F.

    1991-01-01

    This communication reports the first systematic study on background gas-induced spectral-line-emission enhancement from laser-produced plasmas. Line emission from aluminum plasmas was enhanced by factors of up to 35 by the introduction of He, Ne, Xe, or N2. The enhancement has been attributed to three-body recombination.

  6. Remote sensing of plasma injection and acceleration phenomena

    SciTech Connect

    Burch, J.L.

    1985-01-01

    Dynamics Explorer-1 High Altitude Plasma Instrument data have been used to investigate the injection of magnetosheath plasma into the polar cusp, the injection of auroral ion beams into the magnetosphere, and the acceleration of electrons transverse to the magnetic field direction, and the results are discussed. In the case of polar cusp plasmas, it is found that injection occurs at the high-latitude magnetopause, at geocentric distances near eight earth radii. In the case of auroral ion beams it is determined that ion bands are not produced by equatorial injection from the plasma sheet, but by the upward acceleration of ions from auroral acceleration regions. Finally, conical electron distributions are found to be consistent with transverse acceleration at altitudes of a thousand or more km, within or below the magnetic-field-aligned potential drops of the auroral acceleration regions.

  7. Low-Temperature Silicon Epitaxy by Remote, Plasma - Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Habermehl, Scott Dwight

    The dynamics of low temperature Si homoepitaxial and heteroepitaxial growth, by remote plasma enhanced chemical vapor deposition, RPECVD, have been investigated. For the critical step of pre-deposition surface preparation of Si(100) surfaces, the attributes of remote plasma generated atomic H are compared to results obtained with a rapid thermal desorption, RTD, technique and a hybrid H-plasma/RTD technique. Auger electron spectroscopy, AES, and electron diffraction analysis indicate the hybrid technique to be very effective at surface passivation, while the RTD process promotes the formation of SiC precipitates, which induce defective epitaxial growth. For GaP and GaAs substrates, the use of atomic H exposure is investigated as a surface passivation technique. AES shows this technique to be effective at producing atomically clean surfaces. For processing at 400^circrm C, the GaAs(100) surface is observed to reconstruct to a c(8 x 2)Ga symmetry while, at 530^ circrm C the vicinal GaP(100) surface, miscut 10^circ , is observed to reconstruct to a (1 x n) type symmetry; an unreconstructed (1 x 1) symmetry is observed for GaP(111). Differences in the efficiency with which native oxides are removed from the surface are attributed to variations in the local atomic bonding order of group V oxides. The microstructure of homoepitaxial Si films, deposited at temperatures of 25-450^circ rm C and pressures of 50-500 mTorr, is catalogued. Optimized conditions for the deposition of low defect, single crystal films are identified. The existence of two pressure dependent regimes for process activation are observed. In-situ mass spectral analysis indicates that the plasma afterglow is dominated by monosilane ions below 200 mTorr, while above 200 mTorr, low mass rm H_{x} ^+ (x = 1,2,3) and rm HHe^+ ions dominate. Consideration of the growth rate data indicates that downstream dissociative silane ionization, in the lower pressure regime, is responsible for an enhanced surface H

  8. Surface modification of a biomedical poly(ether)urethane by a remote air plasma

    NASA Astrophysics Data System (ADS)

    Gray, J. E.; Norton, P. R.; Griffiths, K.

    2003-07-01

    Plasma modification of polymer surfaces is widely used, but the plasma/polymer interaction is very complex and still not fully understood. In this paper, the interaction of a biomedical poly(ether)urethane with a remote air plasma treatment has been studied. Atomic force microscopy studies show the domain structure of the polymer as well as the absence of any surface roughening due to plasma treatment. Contact angle goniometry shows an improved wettability of the surface after plasma treatment. X-ray photoelectron spectroscopy indicates an increase in CO and CC at the surface, as well as the presence of new functional groups such as alcohols, ketones, aldehydes and imines. There is also evidence that the energy imparted to the polymer during plasma treatment causes surface segregation of polyol segments.

  9. Enhancement of human plasma glucosylceramide assay sensitivity using delipidized plasma.

    PubMed

    Zheng, Kefei; Ji, Allena; Chung, Lee Lee; Culm-Merdek, Kerry; Liu, Hanlan; Richards, Susan; Sung, Crystal

    2016-09-01

    Glucosylceramide (GL-1) level in human has been considered as a surrogate biomarker for enzyme replacement and substrate reduction therapies (ERT and SRT) for Gaucher and Fabry patients. Due to the high endogenous level of GL-1 in human plasma, it is difficult to achieve the analytical sensitivity of plasma GL-1 below the normal endogenous level (1.7 μg/mL to 6.6 μg/mL) when using the standard addition method and regular plasma matrix for standard curve. A high sensitivity plasma GL-1 assay with LLOQ at 0.1 μg/mL was developed and validated using delipidized plasma so that patient plasma concentrations that are below normal reference range can be measured accurately. The normal reference range was established from 120 healthy donors using this developed new method. Twenty-three Fabry patient plasma samples including baseline and post-investigation drug treatment samples were measured. All post-treatment samples showed GL-1 concentration below 2.0 μg/mL, indicating the utility of the reported high sensitivity assay using delipidized plasma for monitoring the plasma GL-1 biomarker level in patients. PMID:27547732

  10. Surface analysis of polymers treated by remote atmospheric pressure plasma.

    PubMed

    Gonzalez, Eleazar; Hicks, Robert F

    2010-03-01

    The surfaces of high-density polyethylene (HDPE), poly(methyl methacrylate) (PMMA), and polyethersulfone (PES) were treated with a low-temperature, atmospheric pressure oxygen and helium plasma. The polymers were exposed to the downstream afterglow of the plasma, which contained primarily oxygen atoms and metastable oxygen molecules ((1)Delta(g) O(2)), and no ions or electrons. X-ray photoelectron spectroscopy (XPS) of HDPE revealed that 20% of the carbon atoms were converted into oxidized functional groups, with about half of these being carboxylic acids. Attenuated total reflection infrared spectroscopy of all three polymers was obtained in order to determine the types of functional groups formed by atmospheric plasma exposure. It was found that the polymers were rapidly oxidized with addition of alcohols, ketones, and carboxylic acids to the carbon backbone. Chain scission occurred on HDPE and PMMA, while on PES the aromatic groups underwent ring-opening and insertion of carboxylic acid. PMID:19950952

  11. Remote Plasma Oxidation and Atomic Layer Etching of MoS2.

    PubMed

    Zhu, Hui; Qin, Xiaoye; Cheng, Lanxia; Azcatl, Angelica; Kim, Jiyoung; Wallace, Robert M

    2016-07-27

    Exfoliated molybdenum disulfide (MoS2) is shown to chemically oxidize in a layered manner upon exposure to a remote O2 plasma. X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and atomic force microscopy (AFM) are employed to characterize the surface chemistry, structure, and topography of the oxidation process and indicate that the oxidation mainly occurs on the topmost layer without altering the chemical composition of underlying layer. The formation of S-O bonds upon short, remote plasma exposure pins the surface Fermi level to the conduction band edge, while the MoOx formation at high temperature modulates the Fermi level toward the valence band through band alignment. A uniform coverage of monolayer amorphous MoO3 is obtained after 5 min or longer remote O2 plasma exposure at 200 °C, and the MoO3 can be completely removed by annealing at 500 °C, leaving a clean ordered MoS2 lattice structure as verified by XPS, LEED, AFM, and scanning tunneling microscopy. This work shows that a remote O2 plasma can be useful for both surface functionalization and a controlled thinning method for MoS2 device fabrication processes. PMID:27386734

  12. TiN Deposition and Process Diagnostics using Remote Plasma Sputtering

    NASA Astrophysics Data System (ADS)

    Yang, Wonkyun; Kim, Gi-Taek; Lee, Seunghun; Kim, Do-Geun; Kim, Jong-Kuk

    2013-08-01

    The discharge voltage-current characteristics and the optical diagnostics of a remote plasma sputtering system called by high density plasma assisted sputtering source (HiPASS) were investigated. The remote plasma was generated by the hollow cathode discharge (HCD) gun and was transported to the target surface by external electromagnet coils. This showed a wide process window because the sputtering voltage and current could be individually controlled. The ion density and energy distribution could be also controlled unlike the conventional magnetron sputtering. Titanium nitride films were deposited under different sputtering voltage. The high voltage mode induced the high ionization ratio of the sputtered atoms and the high ion energy toward the substrate. That resulted in the enlarged grain size, and the preferred orientation toward (220). Eventually, this optimized condition of HiPASS obtained the best hardness of TiN films to be about 48 GPa at the sputtering voltage of -800 V.

  13. Plasma enhancement of combustion of solid fuels

    SciTech Connect

    Askarova, A.S.; Karpenko, E.I.; Messerle, V.E.; Ustimenko, A.B.

    2006-03-15

    Plasma fuel systems that increase the coal burning efficiency are discussed. The systems were tested for fuel oil-free startup of boilers and stabilizating a pulverized-coal flame in power-generating boilers equipped with different types of burner and burning all types of power-generating coal. Plasma ignition, thermochemical treatment of an air-fuel mixture prior to combustion, and its burning in a power-generating boiler were numerically simulated. Environmental friendliness of the plasma technology was demonstrated.

  14. Visualization of remotely sensed heliospheric plasmas for space weather applications

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Hick, P. P.; Jackson, Bernard V.; Bailey, Mike

    2004-02-01

    We demonstrate a software application designed for the display and interactive manipulation of 3D heliospheric volume data, such as solar wind density, velocity and magnetic field. The Volume Explorer software exploits the capabilities of the Volume Pro 1000 (from TeraRecon, Inc.), a low-cost 64-bit PCI board capable of rendering a 512-cubed array of volume data in real time at up to 30 frames per second on a standard PC. The application allows stereo and perspective views, and animations of time-sequences. We show examples of three-dimensional heliospheric volume data derived from tomographic reconstructions based on heliospheric remote sensing observations of the heliospheric density and velocity structure. Currently these reconstructions are based on archival IPS and Thomson scattering data. In the near future we expect to add reconstructions based on the all-sky observations from the recently launched Solar Mass Ejection Imager.

  15. Hydrogen desorption kinetics for aqueous hydrogen fluoride and remote hydrogen plasma processed silicon (001) surfaces

    SciTech Connect

    King, Sean W. Davis, Robert F.; Carter, Richard J.; Schneider, Thomas P.; Nemanich, Robert J.

    2015-09-15

    The desorption kinetics of molecular hydrogen (H{sub 2}) from silicon (001) surfaces exposed to aqueous hydrogen fluoride and remote hydrogen plasmas were examined using temperature programmed desorption. Multiple H{sub 2} desorption states were observed and attributed to surface monohydride (SiH), di/trihydride (SiH{sub 2/3}), and hydroxide (SiOH) species, subsurface hydrogen trapped at defects, and hydrogen evolved during the desorption of surface oxides. The observed surface hydride species were dependent on the surface temperature during hydrogen plasma exposure with mono, di, and trihydride species being observed after low temperature exposure (150 °C), while predominantly monohydride species were observed after higher temperature exposure (450 °C). The ratio of surface versus subsurface H{sub 2} desorption was also found to be dependent on the substrate temperature with 150 °C remote hydrogen plasma exposure generally leading to more H{sub 2} evolved from subsurface states and 450 °C exposure leading to more H{sub 2} desorption from surface SiH{sub x} species. Additional surface desorption states were observed, which were attributed to H{sub 2} desorption from Si (111) facets formed as a result of surface etching by the remote hydrogen plasma or aqueous hydrogen fluoride treatment. The kinetics of surface H{sub 2} desorption were found to be in excellent agreement with prior investigations of silicon surfaces exposed to thermally generated atomic hydrogen.

  16. ENHANCEMENTS OF REMOTE SENSING FOR VEHICLE EMISSIONS IN TUNNELS

    EPA Science Inventory

    The University of Denver in cooperation with the Desert Research Institute, U.S. EPA, and General Motors Corporation have successfully adapted the University of Denver's remote sensing system for vehicle exhaust to the measurement of vehicles in a tunnel environment. wo studies c...

  17. The application of image enhancement techniques to remote manipulator operation

    NASA Technical Reports Server (NTRS)

    Gonzalez, R. C.

    1974-01-01

    Methods of image enhancement which can be used by an operator who is not experienced with the mechanisms of enhancement to obtain satisfactory results were designed and implemented. Investigation of transformations which operate directly on the image domain resulted in a new technique of contrast enhancement. Transformations on the Fourier transform of the original image, including such techniques as homomorphic filtering, were also investigated. The methods of communication between the enhancement system and the computer operator were analyzed, and a language was developed for use in image enhancement. A working enhancement system was then created, and is included.

  18. Spatial distribution of the electrical potential and ion concentration in the downstream area of atmospheric pressure remote plasma

    NASA Astrophysics Data System (ADS)

    Mishin, M. V.; Protopopova, V. S.; Uvarov, A. A.; Alexandrov, S. E.

    2014-10-01

    This paper presents the results from an experimental study of the ion flux characteristics behind the remote plasma zone in a vertical tube reaction chamber for atmospheric pressure plasma enhanced chemical vapor deposition. Capacitively coupled radio frequency plasma was generated in pure He and gas mixtures: He-Ar, He-O2, He-TEOS. We previously used the reaction system He-TEOS for the synthesis of self-assembled structures of silicon dioxide nanoparticles. It is likely that the electrical parameters of the area, where nanoparticles have been transported from the synthesis zone to the substrate, play a significant role in the self-organization processes both in the vapor phase and on the substrate surface. The results from the spatial distribution of the electrical potential and ion concentration in the discharge downstream area measured by means of the external probe of original design and the special data processing method are demonstrated in this work. Positive and negatives ions with maximum concentrations of 106-107 cm-3 have been found at 10-80 mm distance behind the plasma zone. On the basis of the revealed distributions for different gas mixtures, the physical model of the observed phenomena is proposed. The model illustrates the capability of the virtual ion emitter formation behind the discharge gap and the presence of an extremum of the electrical potential at the distance of approximately 10-2-10-1 mm from the grounded electrode.

  19. Enhanced laser beam coupling to a plasma

    DOEpatents

    Steiger, Arno D.; Woods, Cornelius H.

    1976-01-01

    Density perturbations are induced in a heated plasma by means of a pair of oppositely directed, polarized laser beams of the same frequency. The wavelength of the density perturbations is equal to one half the wavelength of the laser beams. A third laser beam is linearly polarized and directed at the perturbed plasma along a line that is perpendicular to the direction of the two opposed beams. The electric field of the third beam is oriented to lie in the plane containing the three beams. The frequency of the third beam is chosen to cause it to interact resonantly with the plasma density perturbations, thereby efficiently coupling the energy of the third beam to the plasma.

  20. Enhanced laser-induced plasma channels in air

    NASA Astrophysics Data System (ADS)

    Yanlei, Zuo; Xiaofeng, Wei; Kainan, Zhou; Xiaoming, Zeng; Jingqin, Su; Zhihong, Jiao; Na, Xie; Zhaohui, Wu

    2016-03-01

    Plasma is a significant medium in high-energy density physics since it can hardly be damaged. For some applications such as plasma based backward Raman amplification (BRA), uniform high-density and large-scale plasma channels are required. In the previous experiment, the plasma transverse diameter and density are 50-200 μm and 1-2 × 1019 cm-3, here we enhance them to 0.8 mm and 8 × 1019 cm-3, respectively. Moreover, the gradient plasma is investigated in our experiment. A proper plasma gradient can be obtained with suitable pulse energy and delay. The experimental results are useful for plasma physics and nonlinear optics. Project supported by the Development Foundation of the Chinese Academy of Engineering Physics (Grant Nos. 2012A0401019 and 2013A0401019).

  1. Regimes of enhanced electromagnetic emission in beam-plasma interactions

    NASA Astrophysics Data System (ADS)

    Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V.

    2015-11-01

    The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.

  2. Regimes of enhanced electromagnetic emission in beam-plasma interactions

    SciTech Connect

    Timofeev, I. V.; Annenkov, V. V.; Arzhannikov, A. V.

    2015-11-15

    The ways to improve the efficiency of electromagnetic waves generation in laboratory experiments with high-current relativistic electron beams injected into a magnetized plasma are discussed. It is known that such a beam can lose, in a plasma, a significant part of its energy by exciting a high level of turbulence and heating plasma electrons. Beam-excited plasma oscillations may simultaneously participate in nonlinear processes resulting in a fundamental and second harmonic emissions. It is obvious, however, that in the developed plasma turbulence the role of these emissions in the total energy balance is always negligible. In this paper, we investigate whether electromagnetic radiation generated in the beam-plasma system can be sufficiently enhanced by the direct linear conversion of resonant beam-driven modes into electromagnetic ones on preformed regular inhomogeneities of plasma density. Due to the high power of relativistic electron beams, the mechanism discussed may become the basis for the generator of powerful sub-terahertz radiation.

  3. Nitriding characteristics of 4H-SiC irradiated with remote nitrogen plasmas

    NASA Astrophysics Data System (ADS)

    Shimabayashi, Masaharu; Kurihara, Kazuaki; Horikawa, Yoshimine; Sasaki, Koichi

    2016-03-01

    We examined the atomic concentrations and the weight densities of SiC surfaces irradiated with remote nitrogen plasmas. The unique approach of this work is that we compared the SiC surface irradiated with atomic nitrogen with that irradiated with a mixture of atomic nitrogen and molecular nitrogen in the metastable \\text{A}3Σ \\text{u} + state. As a result, it was found that molecular nitrogen in the \\text{A}3Σ \\text{u} + state has a higher efficiency than atomic nitrogen in the nitriding of SiC surfaces. The weight density measurements have revealed the removal of Si and C from the SiC surface by the irradiation of remote nitrogen plasma. These results suggest that the formation of volatile molecules is less significant when the SiC surface is irradiated with molecular nitrogen in the metastable \\text{A}3Σ \\text{u} + state.

  4. PTFE treatment by remote atmospheric Ar/O2 plasmas: a simple reaction scheme model proposal

    NASA Astrophysics Data System (ADS)

    Carbone, E. A. D.; Verhoeven, M. W. G. M.; Keuning, W.; van der Mullen, J. J. A. M.

    2016-05-01

    Polytetrafluoroethylene (PTFE) samples were treated by a remote atmospheric pressure microwave plasma torch and analyzed by water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS). In the case of pure argon plasma a decrease of WCA is observed meanwhile an increase of hydrophobicity was observed when some oxygen was added to the discharge. The WCA results are correlated to XPS of reference samples and the change of WCA are attributed to changes in roughness of the samples. A simple kinetics scheme for the chemistry on the PTFE surface is proposed to explain the results.

  5. The dawn enhancement of the equatorial ionospheric vertical plasma drift

    NASA Astrophysics Data System (ADS)

    Zhang, Ruilong; Liu, Libo; Chen, Yiding; Le, Huijun

    2015-12-01

    Previous studies have reported that a dawn enhancement does not present in the statistical picture of the equatorial ionospheric vertical plasma drift, while it clearly shows in case measurements. In this statistical study, it is the first time to investigate the occurrence of the dawn enhancement in the equatorial ionospheric vertical plasma drift from ROCSAT-1 observations during geomagnetic quiet times. The dawn enhancements occur most frequently in June solstice and least frequently in December solstice. The statistical survey shows that the occurrence depends on the magnetic declination. The enhancement has the strongest amplitude in regions near 320° longitude and peaks during June solstice. The dawn enhancement reaches its peak after the sunrise in conjugated E regions. Furthermore, it is found that the dawn enhancement is closely related to the difference between the sunrise times in the conjugated E regions (sunrise time lag). The dawn enhancement occurs easily in regions with a large sunrise time lag.

  6. In situ technique for measurement and control of transistor characteristics during remote plasma etching

    NASA Astrophysics Data System (ADS)

    Lishan, David; Hu, Evelyn

    1991-09-01

    In situ electrical monitoring has been carried out in a remote plasma etching system allowing accurate control of device electrical parameters. We have used this technique to gate recess-etch two different high electron mobility transistor structures while recording device source-drain I-V characteristics throughout the etching. Current versus etching time data and time elapsed I-V curves are presented.

  7. Localised plasma density enhancements around comet CG/67P

    NASA Astrophysics Data System (ADS)

    Henri, Pierre; Broiles, Tom; Eriksson, Anders; Béghin, Christian; Lebreton, Jean-Pierre; Vallieres, Xavier; More, Jerome; Wattieaux, Gaetan; Engelhardt, Ilka A. D.; Edberg, Niklas; Odelstad, Elias; Vigren, Erik; Glassmeier, Karl-Heinz; Goetz, Charlotte; Koenders, Christoph; Richter, Ingo; Volwerk, Martin; Burch, James L.; Goldstein, Ray; Mandt, Kathleen

    2016-04-01

    Comet 67P/Churyumov-Gerasimenko, target of the ESA's Rosetta mission, reached its perihelion at 1.3 AU from the Sun in August 2015. Its plasma environment will go on being monitored by the Rosetta Plasma Consortium (RPC) as the distance to the sun increases, until end of mission in September 2016. Combining observations from the different RPC sensors, we investigate localised, strong enhancements of the cometary plasma density over short timescales (~ minutes to seconds) observed during the period April 2015 - January 2016. These strong plasma density variations (RPC-MIP and RPC-LAP) are likely associated to cold electrons (RPC-IES) and generally observed during magnetic field rotations (RPC-MAG). The location of such events, both in the rotating comet frame and with regard to the magnetic field direction, is discussed to better constrain the mechanism at the origin of these localised plasma density enhancements.

  8. Toroidal plasma enhanced CVD of diamond films

    SciTech Connect

    Zvanya, John Cullen, Christopher Morris, Thomas Krchnavek, Robert R.; Holber, William Basnett, Andrew Basnett, Robert; Hettinger, Jeffrey

    2014-09-01

    An inductively coupled toroidal plasma source is used as an alternative to microwave plasmas for chemical vapor deposition of diamond films. The source, operating at a frequency of 400 kHz, synthesizes diamond films from a mixture of argon, methane, and hydrogen. The toroidal design has been adapted to create a highly efficient environment for diamond film deposition: high gas temperature and a short distance from the sample to the plasma core. Using a toroidal plasma geometry operating in the medium frequency band allows for efficient (≈90%) coupling of AC line power to the plasma and a scalable path to high-power and large-area operation. In test runs, the source generates a high flux of atomic hydrogen over a large area, which is favorable for diamond film growth. Using a deposition temperature of 900–1050 °C and a source to sample distance of 0.1–2.0 cm, diamond films are deposited onto silicon substrates. The results showed that the deposition rate of the diamond films could be controlled using the sample temperature and source to sample spacing. The results also show the films exhibit good-quality polycrystalline diamond as verified by Raman spectroscopy, x-ray diffraction, and scanning electron microscopy. The scanning electron microscopy and x-ray diffraction results show that the samples exhibit diamond (111) and diamond (022) crystallites. The Raman results show that the sp{sup 3} peak has a narrow spectral width (FWHM 12 ± 0.5 cm{sup −1}) and that negligible amounts of the sp{sup 2} band are present, indicating good-quality diamond films.

  9. Diagnostics of N2 Ar plasma mixture excited in a 13.56 MHz hollow cathode discharge system: application to remote plasma treatment of polyamide surface

    NASA Astrophysics Data System (ADS)

    Saloum, S.; Naddaf, M.; Alkhaled, B.

    2008-02-01

    N2-x% Ar plasma gas mixture, generated in a hollow cathode RF discharge system, has been characterized by both optical emission spectroscopy (OES) and double Langmuir probe, as a function of experimental parameters: total pressure (5-33 Pa), and different fractions of argon (7 <= x <= 80), at a constant applied RF power of 300 W. N2 dissociation degree has been investigated qualitatively by both the actinometry method and the ratio I_N/I_{N_2} of the atomic nitrogen line emission intensity at 672.3 nm to the vibrational band (0-0) of the N2 second positive system at 337.1 nm. Both methods showed that the increase in argon fraction enhances the dissociation of N2, with a maximum at x = 50 for the pressure of 5 Pa, although the two methods give two opposite trends as a function of total pressure. Spectroscopic measurements showed that the vibrational temperature of the N2 second positive system increases with both argon fraction and total pressure increase, it lies between 4900 and 12 300 K. Langmuir probe measurements showed that, in the remote zone, the electron temperature falls in the range 1.57-1.75 eV, the N_{2}^{+} density varies between 5 × 109 and 1.4 × 1010 cm-3 and that both the plasma ionization degree and electron temperature increase towards the source. In addition, the process of plasma-polyamide (PA) surface interaction, in the remote plasma zone, has been studied through OES analysis during plasma treatment of PA to monitor the possible emissions due to the polymer etching. An increase in atomic nitrogen line (672.3 nm) intensity is obtained, atomic carbon line (833.52 nm) and the band emission (0-0) from the CN (B 2Σ+-X 2Σ+) violet system were observed. The PA surface modification has been confirmed through the improvement of its hydrophilic character as the water contact angle measured after the plasma treatment significantly decreased.

  10. Dielectric properties in microwave remote plasma sustained in argon: Expanding plasma conditions

    SciTech Connect

    Jauberteau, J. L.; Jauberteau, I.

    2012-11-15

    This work is devoted to the study of the relative permittivity in argon expanding plasma produced below a microwave discharge sustained in a quartz tube and working at 2.45 GHz. We discuss results and explain the microwave propagation within the reactor, outside the quartz tube. It is shown that at low pressures (133 Pa) and at powers ranging from 100 W to 400 W, the wave frequency remains lower than the plasma frequency anywhere in the expanding plasma. Under these conditions, the real part of the relative permittivity is negative and the wave is reflected. Surprisingly, in these conditions, the plasma is produced inside and outside the quartz tube, below the wave launcher. This effect can be explained considering a surface wave propagating at the surface of the quartz tube then into the reactor, on the external surface of the expanding plasma below the quartz tube.

  11. A study of increasing radical density and etch rate using remote plasma generator system

    NASA Astrophysics Data System (ADS)

    Lee, Jaewon; Kim, Kyunghyun; Cho, Sung-Won; Chung, Chin-Wook

    2013-09-01

    To improve radical density without changing electron temperature, remote plasma generator (RPG) is applied. Multistep dissociation of the polyatomic molecule was performed using RPG system. RPG is installed to inductively coupled type processing reactor; electrons, positive ions, radicals and polyatomic molecule generated in RPG and they diffused to processing reactor. The processing reactor dissociates the polyatomic molecules with inductively coupled power. The polyatomic molecules are dissociated by the processing reactor that is operated by inductively coupled power. Therefore, the multistep dissociation system generates more radicals than single-step system. The RPG was composed with two cylinder type inductively coupled plasma (ICP) using 400 kHz RF power and nitrogen gas. The processing reactor composed with two turn antenna with 13.56 MHz RF power. Plasma density, electron temperature and radical density were measured with electrical probe and optical methods.

  12. Reflections From Plasma Would Enhance Infrared Detector

    NASA Technical Reports Server (NTRS)

    Maserjian, Joseph

    1992-01-01

    Quantum efficiency of proposed photoemission semiconductor detector of long-wavelength infrared radiation enhanced by multiple passes of radiation. Device has features of back-to-back heterojunction internal-photoemission (HIP) detector, and Fabry-Perot interferometer. Arrays of devices of this type incorporated into integrated-circuit infrared imaging devices.

  13. Bleeding management in remote environment: the use of fresh whole blood transfusion and lyophilised plasma.

    PubMed

    Sicard, Bruno; Marouzé, Frédéric; Roche, Céline; Carron, Mathieu; Ausset, Sylvain; Sailliol, Anne

    2016-01-01

    To mitigate medical risks in remote environments, the authors have implemented an innovative integrated medical support solution for bleeding management on board ships since 2013. Fresh whole blood transfusion (FWBT) and lyophilised plasma were put in place to address life threatening haemorrhages in maritime operations in the Arctic and Antarctica. The authors are illustrating the bleeding risks with an actual case occurring in Antarctica prior to the implementation of these procedures. They are presenting the different steps involved in the complex process of FWBT, from blood donors' qualifications to actual transfusions. The pros and cons of blood transfusion in extreme remote environment are discussed, including the training of health care professionals, equipment requirements, legal and ethical issues, decision making in complex blood group matching, medical benefits and risks. PMID:27364172

  14. Optimization of hollow cathode discharge electrode for damage free remote plasma removal process for semiconductor manufacturing

    NASA Astrophysics Data System (ADS)

    Cho, Tae S.; Han, Qing; Yang, Dongqing; Park, Soonam; Lubomirsky, Dima; Venkataraman, Shankar

    2016-05-01

    Cone-shaped hollow cathode electrode configuration for a damage free remote plasma removal process has been optimized for given pressures based on Paschen characteristic curves, voltage-current characteristics and time-resolved discharge observations as well as oxide film removal performances. Remote plasmas have been generated in two types of cone-shaped electrodes with mixtures of He, NF3, and NH3 for pressure range of 1-30 Torr. Paschen characteristic curves and voltage-current (V-I) characteristics define an operating pressure for low breakdown voltage and the hollow cathode effect to minimize the particles. Sinusoidal voltage waveform and asymmetry electrode configuration alternate the glow discharge and hollow cathode discharge modes in a cycle. The current and infrared emission intensity from the glow discharge increases together for both cone-shaped electrodes with increasing pressure, whereas the hollow cathode discharge plasma emits strong infrared only when pD condition is satisfied. For the wide cone electrode configuration, high voltage operation at higher pressure results in particle contamination on the processed wafer by high energy ion bombardment. Operating at optimum pressure for a given electrode configuration shows faster oxide etch rate with better uniformity over a whole 300 mm wafer.

  15. Real time characterization of polymer surface modifications by an atmospheric-pressure plasma jet: Electrically coupled versus remote mode

    NASA Astrophysics Data System (ADS)

    Knoll, A. J.; Luan, P.; Bartis, E. A. J.; Hart, C.; Raitses, Y.; Oehrlein, G. S.

    2014-10-01

    We characterize and distinguish two regimes of atmospheric pressure plasma (APP) polymer interactions depending on whether the electrical interaction of the plasma plume with the surface is significant (coupled) or not (remote). When the plasma is coupled to the surface, localized energy deposition by charged species in filaments dominates the interactions with the surface and produces contained damaged areas with high etch rates that decrease rapidly with plasma source-to-sample distance. For remote APP surface treatments, when only reactive neutral species interact with the surface, we established specific surface-chemical changes and very slow etching of polymer films. Remote treatments appear uniform with etch rates that are highly sensitive to feed gas chemistry and APP source temperature.

  16. Characteristics of Plasma Using a Ferromagnetic Enhanced Inductively Coupled Plasma Source

    NASA Astrophysics Data System (ADS)

    Kim, Kyong Nam; Hyeuk Lim, Jong; Park, Jung Kyun; Lim, Jong Tae; Yeom, Geun Young

    2008-09-01

    Plasma characteristics and electrical parameters of an internal linear inductively coupled plasma (ICP) source with a U-type antenna with/without a Ni-Zn ferromagnetic material installed near the antenna were investigated. The application of the ferromagnetic material to the antenna increased the plasma density, improved the plasma uniformity, lowered the antenna voltage, and increased the stability of the plasma during the operation. For the U-type ferromagnetic enhanced internal linear ICP source, a high density plasma on the order of 4.5×1011 cm-3 which is about three higher than that obtained for the source without the ferromagnetic material could be obtained at the pressure of 10 mTorr Ar and at the RF power of 600 W at 13.56 MHz.

  17. Patterning of graphene for flexible electronics with remote atmospheric-pressure plasma using dielectric barrier

    NASA Astrophysics Data System (ADS)

    Kim, Duk Jae; Park, Jeongwon; Geon Han, Jeon

    2016-08-01

    We show results of the patterning of graphene layers on poly(ethylene terephthalate) (PET) films through remote atmospheric-pressure dielectric barrier discharge plasma. The size of plasma discharge electrodes was adjusted for large-area and role-to-role-type substrates. Optical emission spectroscopy (OES) was used to analyze the characteristics of charge species in atmospheric-pressure plasma. The OES emission intensity of the O2* peaks (248.8 and 259.3 nm) shows the highest value at the ratio of \\text{N}2:\\text{clean dry air (CDA)} = 100:1 due to the highest plasma discharge. The PET surface roughness and hydrophilic behavior were controlled with CDA flow rate during the process. Although the atmospheric-pressure plasma treatment of the PET film led to an increase in the FT-IR intensity of C–O bonding at 1240 cm‑1, the peak intensity at 1710 cm‑1 (C=O bonding) decreased. The patterning of graphene layers was confirmed by scanning electron microscopy and Raman spectroscopy.

  18. Oxygen plasma surface modification enhances immobilization of simvastatin acid.

    PubMed

    Yoshinari, Masao; Hayakawa, Tohru; Matsuzaka, Kenichi; Inoue, Takashi; Oda, Yutaka; Shimono, Masaki; Ide, Takaharu; Tanaka, Teruo

    2006-02-01

    Simvastatin acid (SVA) has been reported to stimulate bone formation with increased expression of BMP-2. Therefore, immobilization of SVA onto dental implants is expected to promote osteogenesis at the bone tissue/implant interface. The aim of this study was to evaluate the immobilization behavior of SVA onto titanium (Ti), O(2)-plasma treated titanium (Ti + O(2)), thin-film coatings of hexamethyldisiloxane (HMDSO), and O(2)-plasma treated HMDSO (HMDSO + O(2)) by using the quartz crystal microbalance-dissipation (QCM-D) technique. HMDSO surfaces were activated by the introduction of an OH group and/or O(2)-functional groups by O(2)-plasma treatment. In contrast, titanium surfaces showed no appreciable compositional changes by O(2)-plasma treatment. The QCM-D technique enabled evaluation even at the adsorption behavior of a substance with a low molecular weight such as simvastatin. The largest amount of SVA was adsorbed on O(2)-plasma treated HMDSO surfaces compared to untreated titanium, HMDSO-coated titanium, and O(2)-plasma treated titanium. These findings suggested that the adsorption of SVA was enhanced on more hydrophilic surfaces concomitant with the presence of an OH group and/or O(2)-functional group resulting from the O(2)-plasma treatment, and that an organic film of HMDSO followed by O(2)-plasma treatment is a promising method for the adsorption of SVA in dental implant systems. PMID:16543663

  19. Using ICT to Enhance Curriculum Opportunities for Students in Rural and Remote Schools

    ERIC Educational Resources Information Center

    White, Bruce

    2010-01-01

    South Australian rural and remote schools have been using a variety of Information and Communication Technologies (ICT) to enhance curriculum opportunities for students whose teachers are at a different campus or different school, or who are out of the school for extended periods of time undertaking courses, such as, Vocational Education and…

  20. Raman backscatter as a remote laser power sensor in high-energy-density plasmas.

    PubMed

    Moody, J D; Strozzi, D J; Divol, L; Michel, P; Robey, H F; LePape, S; Ralph, J; Ross, J S; Glenzer, S H; Kirkwood, R K; Landen, O L; MacGowan, B J; Nikroo, A; Williams, E A

    2013-07-12

    Stimulated Raman backscatter is used as a remote sensor to quantify the instantaneous laser power after transfer from outer to inner cones that cross in a National Ignition Facility (NIF) gas-filled hohlraum plasma. By matching stimulated Raman backscatter between a shot reducing outer versus a shot reducing inner power we infer that about half of the incident outer-cone power is transferred to inner cones, for the specific time and wavelength configuration studied. This is the first instantaneous nondisruptive measure of power transfer in an indirect drive NIF experiment using optical measurements. PMID:23889410

  1. Enhanced magnetic ionization in hydrogen reflex discharge plasma source

    SciTech Connect

    Toader, E.I.; Covlea, V.N.

    2005-03-01

    The effect of enhanced magnetic ionization on the external and internal parameters of a high-density, low pressure reflex plasma source operating in hydrogen is studied. The Langmuir probe method and Druyvesteyn procedure coupled with suitable software are used to measure the internal parameters. The bulk plasma region is free of an electric field and presents a high degree of uniformity. The electron energy distribution function is bi-Maxwellian with a dip/shoulder structure around 5.5 eV, independent of external parameters and radial position. Due to the enhanced hollow cathode effect by the magnetic trapping of electrons, the electron density n{sub e} is as high as 10{sup 18} m{sup -3}, and the electron temperature T{sub e} is as low as a few tens of an electron volt, for dissipated energy of tens of Watts. The bulk plasma density scales with the dissipated power.

  2. Enhancement of Space Plasma Images by Complex Wavelets

    NASA Astrophysics Data System (ADS)

    Souza, Vitor Moura; Domingues, Margarete Oliveira; Mendes, Odim; Pagamisse, Aylton; Stenborg, Guillermo Adrian

    2015-10-01

    The Sun is a natural laboratory for plasma processes. A myriad of instruments aboard satellites and on ground record(ed) the plasma emission in different ranges of the electromagnetic spectrum to help understand such processes. In particular, in the outer part of the solar atmosphere, the solar corona, we can observe a multitude of electrodynamical phenomena. There, the faint corona emission and the associated dynamic plasma structures (e.g., coronal mass ejections—CMEs) recorded in white-light images can be used as basis for some insight of this physical scenario. In order to characterize the dynamics and morphology of such structures in a better way, it seems crucial that some features of those images should be enhanced. To deal with this need, a new approach using a complex wavelet transform methodology was developed. With the proposed methodology, we can highlight the plasma ejections improving the identification of those structures.

  3. Enhanced surface functionality via plasma modification and plasma deposition techniques to create more biologically relevant materials

    NASA Astrophysics Data System (ADS)

    Shearer, Jeffrey C.

    Functionalizing nanoparticles and other unusually shaped substrates to create more biologically relevant materials has become central to a wide range of research programs. One of the primary challenges in this field is creating highly functionalized surfaces without modifying the underlying bulk material. Traditional wet chemistry techniques utilize thin film depositions to functionalize nanomaterials with oxygen and nitrogen containing functional groups, such as --OH and --NHx. These functional groups can serve to create surfaces that are amenable to cell adhesion or can act as reactive groups for further attachment of larger structures, such as macromolecules or antiviral agents. Additional layers, such as SiO2, are often added between the nanomaterial and the functionalized coating to act as a barrier films, adhesion layers, and to increase overall hydrophilicity. However, some wet chemistry techniques can damage the bulk material during processing. This dissertation examines the use of plasma processing as an alternative method for producing these highly functionalized surfaces on nanoparticles and polymeric scaffolds through the use of plasma modification and plasma enhanced chemical vapor deposition techniques. Specifically, this dissertation will focus on (1) plasma deposition of SiO2 barrier films on nanoparticle substrates; (2) surface functionalization of amine and alcohol groups through (a) plasma co-polymerization and (b) plasma modification; and (3) the design and construction of plasma hardware to facilitate plasma processing of nanoparticles and polymeric scaffolds. The body of work presented herein first examines the fabrication of composite nanoparticles by plasma processing. SiOxC y and hexylamine films were coated onto TiO2 nanoparticles to demonstrate enhanced water dispersion properties. Continuous wave and pulsed allyl alcohol plasmas were used to produce highly functionalized Fe2 O3 supported nanoparticles. Specifically, film composition was

  4. Effect of silane/hydrogen ratio on microcrystalline silicon thin films by remote inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Guo, Y. N.; Wei, D. Y.; Xiao, S. Q.; Huang, S. Y.; Zhou, H. P.; Xu, S.

    2013-05-01

    Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by remote low frequency inductively coupled plasma (ICP) chemical vapor deposition system, and the effect of silane/hydrogen ratio on the microstructure and electrical properties of μc-Si:H films was systematically investigated. As silane/hydrogen ratio increases, the crystalline volume fraction Fc decreases and the ratio of the intensity of (220) peak to that of (111) peak drops as silane flow rate is increased. The FTIR result indicates that the μc-Si:H films prepared by remote ICP have a high optical response with a low hydrogen content, which is in favor of reducing light-induced degradation effect. Furthermore, the processing window of the phase transition region for remote ICP is much wider than that for typical ICP. The photosensitivity of μc-Si:H films can exceed 100 at the transition region and this ensures the possibility of the fabrication of microcrystalline silicon thin film solar cells with a open-circuit voltage of about 700 mV.

  5. Magnetohydrodynamic turbulence and enhanced atomic processes in astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Spangler, Steven R.

    1998-08-01

    This article discusses a way in which enhanced atomic physics processes, including radiative energy losses, may occur in an astrophysical plasma containing magnetohydrodynamic turbulence. Two-dimensional (2D) magnetohydrodynamics (MHD) is adopted as a model. A major characteristic feature of 2D MHD turbulence is the development of strong current sheets on a dynamical time scale L/V0 where L is the spatial scale of the turbulent fluid and V0 is the scale of the velocity fluctuations. The current contained in the sheets will be carried by an electron drift relative to the ions. The case of a plasma containing minority atoms or ions with an excited state accessible to collisions from the tail of the electron distribution is considered. In the current carrying sheets or filaments, the electron distribution function will be perturbed such that collisional excitations will be enhanced relative to the current-free plasma. Subsequent radiative de-excitation of the atoms or ions removes energy from the turbulence. Expressions are presented for the electron drift velocity arising in 2D turbulence, the enhancement of collisional excitations of a trace atom or ion, and the energy lost to the plasma turbulence by radiative de-excitation of these atoms or ions. The mechanism would be most pronounced in plasmas for which the magnitude of the magnetic field is large, the outer scale of the turbulence is small, and the electron density and temperature are low. A brief discussion of the relevance of this mechanism to some specific astrophysical plasmas is given.

  6. Enhancement of red blood cell aggregation by plasma triglycerides.

    PubMed

    Cicha, I; Suzuki, Y; Tateishi, N; Maeda, N

    2001-01-01

    The effects of plasma triglycerides level on human red blood cells (RBCs) indices, hematological parameters, RBCs aggregation velocity and whole blood viscosity were studied at 2 hours after high-fat or low-fat meal. Proteins, triglycerides and cholesterol levels of plasma were analysed. The RBCs rouleaux formation rate was measured in 70% autologous plasma (with 30% phosphate-buffered saline, PBS) or 1 g/dl dextran T70 solution (with 4 g/dl bovine serum albumin) in PBS, using a low-shear rheoscope. The results were grouped according to triglycerides content in plasma. No significant difference in whole blood viscosity, hematological parameters, RBC indices, protein and cholesterol content was observed between high-fat and low-fat blood samples. There was a significant increase in rouleaux formation rate of samples with high triglyceride levels, when measured in 70% autologous plasma, but it was not significant in dextran T70 containing medium. In conclusion, the results obtained suggest that alteration of plasma lipid levels as well as possible changes in the cell membrane lipid composition lead to enhanced RBC aggregation. PMID:11564913

  7. Elemental abundances of flaring solar plasma - Enhanced neon and sulfur

    NASA Technical Reports Server (NTRS)

    Schmelz, J. T.

    1993-01-01

    Elemental abundances of two flares observed with the SMM Flat Crystal Spectrometer are compared and contrasted. The first had a gradual rise and a slow decay, while the second was much more impulsive. Simultaneous spectra of seven bright soft X-ray resonance lines provide information over a broad temperature range and are available throughout both flares, making these events unique in the SMM data base. For the first flare, the plasma seemed to be characterized by coronal abundances but, for the second, the plasma composition could not be coronal, photospheric, or a linear combination of both. A good differential emission measure fit required enhanced neon such that Ne/O = 0.32 +/- 0.02, a value which is inconsistent with the current models of coronal abundances based on the elemental first-ionization potential. Similar values of enhanced neon are found for flaring plasma observed by the SMM gamma-ray spectrometer, in (He-3)-rich solar energetic particle events, and in the decay phase of several long duration soft X-ray events. Sulfur is also enhanced in the impulsive flare, but not as dramatically as neon. These events are compared with two models which attempt to explain the enhanced values of neon and sulfur.

  8. Enhanced field emission of plasma treated multilayer graphene

    SciTech Connect

    Khare, Ruchita T.; More, Mahendra A.; Gelamo, Rogerio V.; Late, Dattatray J. E-mail: csrout@iitbbs.ac.in; Rout, Chandra Sekhar E-mail: csrout@iitbbs.ac.in

    2015-09-21

    Electron emission properties of multilayer graphene (MLG) prepared by a facile exfoliation technique have been studied. Effect of CO{sub 2} Ar, N{sub 2}, plasma treatment was studied using Raman spectroscopy and investigated for field emission based application. The CO{sub 2} plasma treated multilayer graphene shows an enhanced field emission behavior with a low turn on field of 0.18 V/μm and high emission current density of 1.89 mA/cm{sup 2} at an applied field of 0.35 V/μm. Further the plasma treated MLG exhibits excellent current stability at a lower and higher emission current value.

  9. Enhancement effects of flat-mirror reflection on plasma radiation.

    PubMed

    Chen, Jin-zhong; Bai, Jin-ning; Song, Guang-ju; Sun, Jiang; Deng, Ze-chao; Wang, Ying-long

    2013-09-01

    Laser-induced breakdown spectroscopy quality can be improved by using a nanosecond Nd:YAG laser pulse to excite soil samples. To investigate how flat-mirror reflection affects the radiation characteristics of laser-induced plasma, emission spectra of sample elements were recorded using a grating spectrometer and photoelectric detection system. Placing a planar mirror vertically on the sample surface (10 mm mirror to plasma-center axis distance) for flat-mirror reflection increased spectral line intensities of Mg, Al, Fe, and Ba by 93.06%, 159.63%, 93.43%, and 94.61%, respectively. Signal-to-noise ratio increased by 17.56%, 40.21%, 31.29%, and 30%. The radiation enhancement mechanism was clarified using measured plasma parameters. PMID:24085090

  10. Integrated computer-enhanced remote viewing system. Quarterly report No. 2, January--March 1993

    SciTech Connect

    Not Available

    1993-05-03

    The Interactive, Computer-Enhanced, Remote Viewing System (ICERVS) is a system designed to provide a reliable geometric description of a robotic task space in a fashion that enables robotic remediation to be carried out more efficiently and economically than with present systems. The key elements are a faithful way to store empirical data and a friendly user interface that provides an operator with timely access to all that is known about a scene.

  11. Plasmon-enhanced fluorescence of PbS quantum dots for remote near-infrared imaging.

    PubMed

    Wu, Ke; Zhang, Junpei; Fan, Shanshan; Li, Juan; Zhang, Chao; Qiao, Keke; Qian, Lihua; Han, Junbo; Tang, Jiang; Wang, Shuai

    2015-01-01

    Gold nanoparticles with nanoscale protrusions can be synthesized by seed-mediated growth in favor of tuning the surface plasmon band towards the near-infrared regime. Electromagnetic field enhancement makes significant contribution to improve fluorescence emission of PbS quantum dots in the near-infrared window, identifying their application in remote imaging by collecting the scattered fluorescence of their hybrids. PMID:25385256

  12. Enhancement of pulverized coal combustion by plasma technology

    SciTech Connect

    Gorokhovski, M.A.; Jankoski, Z.; Lockwood, F.C.; Karpenko, E.I.; Messerle, V.E.; Ustimenko, A.B.

    2007-07-01

    Plasma-assisted pulverized coal combustion is a promising technology for thermal power plants (TPP). This article reports one- and three- dimensional numerical simulations, as well as laboratory and industrial measurements of coal combustion using a plasma-fuel system (PFS). The chemical kinetic and fluid mechanics involved in this technology are analysed. The results show that a PFS, can be used to promote early ignition and enhanced stabilization of a pulverized coal flame. It is shown that this technology, in addition to enhancing the combustion efficiency of the flame, reduces harmful emissions from power coals of all ranks (brown, bituminous, anthracite and their mixtures). Data summarising the experience of 27 pulverized coal boilers in 16 thermal power plants in several countries (Russia, Kazakhstan, Korea, Ukraine, Slovakia, Mongolia and China), embracing steam productivities from 75 to 670 tons per hour (TPH), are presented. Finally, the practical computation of the characteristics of the PFS, as function of coal properties, is discussed.

  13. Latest innovations in large area web coating technology via plasma enhanced chemical vapor deposition source technology

    SciTech Connect

    George, M. A.; Chandra, H.; Morse, P.; Madocks, J.

    2009-07-15

    In this article, the authors discuss the latest results of our development of large area plasma enhanced chemical vapor deposition (PECVD) source technologies for flexible substrates. A significant challenge is the economical application of thin films for use as vapor barriers, transparent conductive oxides, and optical interference thin films. Here at General Plasma the authors have developed two innovative PECVD source technologies that provide an economical alternative to low temperature sputtering technologies and enable some thin film materials not accessible by sputtering. The Penning Discharge Plasma (PDP trade mark sign ) source is designed for high rate direct PECVD deposition on insulating, temperature sensitive web [J. Modocks, Proceedings of the Society of Vacuum Coaters, 2003 (unpublished), p. 187]. This technology has been utilized to deposit SiO{sub 2} and SiC:H for barrier applications [V. Shamamian et al. Proceedings of the Flexible Displays and Manufacturing Conferrence, 2006 (unpublished)]. The Plasma Beam Source (PBS trade mark sign ) is a remote plasma source that is more versatile for deposition on not only insulating flexible substrates but also conductive or rigid substrates for deposition of thin films that are sensitive to the high ion bombardment flux inherent to the PDP trade mark sign technology. The authors have developed PBS thin film processes in our laboratory for deposition of SiO{sub 2}, SiC:O, SiN:C, SiN:H, ZnO, FeO{sub x}, and Al{sub 2}O{sub 3}. [M. A. George, Conference Proceedings of the Association of Industrial Metallizers, Coaters, and Laminators (AIMCAL), 2007 (unpublished)]. The authors discuss the design of the patented sources, plasma physics, and chemistry of the deposited thin films.

  14. Performance enhancement of IPMC by anisotropic plasma etching process

    NASA Astrophysics Data System (ADS)

    Lee, Seok Hwan; Kim, Chul-Jin; Hwang, Hyun-Woo; Kim, Sung-Joo; Yang, Hyun-Seok; Park, No-Cheol; Park, Young-Pil; Park, Kang-Ho; Lee, Hyung-Kun; Choi, Nak-Jin

    2009-03-01

    Ionic Polymer-Metal Composites (IPMCs) of EAP actuators is famous for its good property of response and durability. The performance of Ionic Polymer-Metal Composites (IPMCs) is an important issue which is affected by many factors. There are two factors for deciding the performance of IPMC. By treating anisotropic plasma etching process to 6 models of the IPMCs, enhanced experimental displacement and force results are obtained. Plasma patterning processes are executed by changing the groove and the land length of 6 patterns. The purpose of the present investigation is to find out the major factor which mainly affects the IPMC performance. Simulations using ANSYS have been executed to compare with the experimental results about the values and the tendency of data. Experimental and simulating data of the performances seem to have similar tendency. In the next part of the paper, we observed the other properties like capacitance, resistance and stiffness of 6 plasma patterned IPMCs. And we observed that the stiffness is the major factor which affects the performance of IPMCs. As we seen, our problem has been reduced to investigate about the property of stiffness. We suggest that the stiffness is largely changed mainly because of the different thickness of Platinum stacked of the groove and the land part which are produced by anisotropic plasma etching processes. And we understand that anisotropic plasma patterned IPMCs of better performance can be applied to various applications.

  15. Radio frequency plasma power dependence of the moisture permeation barrier characteristics of Al{sub 2}O{sub 3} films deposited by remote plasma atomic layer deposition

    SciTech Connect

    Jung, Hyunsoo; Samsung Display Co. Ltd., Tangjeong, Chungcheongnam-Do 336-741 ; Choi, Hagyoung; Lee, Sanghun; Jeon, Heeyoung; Jeon, Hyeongtag; Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791

    2013-11-07

    In the present study, we investigated the gas and moisture permeation barrier properties of Al{sub 2}O{sub 3} films deposited on polyethersulfone films (PES) by capacitively coupled plasma (CCP) type Remote Plasma Atomic Layer Deposition (RPALD) at Radio Frequency (RF) plasma powers ranging from 100 W to 400 W in 100 W increments using Trimethylaluminum [TMA, Al(CH{sub 3}){sub 3}] as the Al source and O{sub 2} plasma as the reactant. To study the gas and moisture permeation barrier properties of 100-nm-thick Al{sub 2}O{sub 3} at various plasma powers, the Water Vapor Transmission Rate (WVTR) was measured using an electrical Ca degradation test. WVTR decreased as plasma power increased with WVTR values for 400 W and 100 W of 2.6 × 10{sup −4} gm{sup −2}day{sup −1} and 1.2 × 10{sup −3} gm{sup −2}day{sup −1}, respectively. The trends for life time, Al-O and O-H bond, density, and stoichiometry were similar to that of WVTR with improvement associated with increasing plasma power. Further, among plasma power ranging from 100 W to 400 W, the highest power of 400 W resulted in the best moisture permeation barrier properties. This result was attributed to differences in volume and amount of ion and radical fluxes, to join the ALD process, generated by O{sub 2} plasma as the plasma power changed during ALD process, which was determined using a plasma diagnosis technique called the Floating Harmonic Method (FHM). Plasma diagnosis by FHM revealed an increase in ion flux with increasing plasma power. With respect to the ALD process, our results indicated that higher plasma power generated increased ion and radical flux compared with lower plasma power. Thus, a higher plasma power provides the best gas and moisture permeation barrier properties.

  16. Infrared spectroscopy of sub-surface defects induced by remote hydrogen plasma exposure of silicon (100)

    SciTech Connect

    Lamb, H.H.; Bedge, S.G.; Wan, Z.

    1998-12-31

    Infrared multiple internal reflection (MIR) spectroscopy was used to investigate the local chemical bonding in sub-surface defects induced by remote hydrogen plasma exposure (RHPE) of Si(100) wafers. Exposure of very lightly doped n-type Si ([P] = 5 {times} 10{sup 13} cm{sup {minus}3}) to a remote hydrogen plasma for 2 min at 200 C results in the formation of Si monohydride species. An intense narrow band at 2078 cm{sup {minus}1} (FWHM = 7 cm{sup {minus}1}) and a small shoulder at 2065 cm{sup {minus}1} are observed. The data are consistent with monohydride termination of Si{l_brace}111{r_brace} platelet defects with a weak interaction between H atoms on opposing internal surfaces. In contrast, platelet nucleation at 200 C followed by growth at 300 C selectively generates Si dihydride species, as evidenced by a single broad infrared band at 2109 cm{sup {minus}1}. The P concentration was found to have a marked influence on the areal density and chemical bonding of sub-surface hydrogen. The MIR spectrum of lightly doped Si ([P] = 2 {times} 10{sup 14} cm{sup {minus}3}) after RHPE at 200 C contains broad peaks at 2078 and 2130 cm{sup {minus}1} consistent with Si monohydride and trihydride species. The authors infer that hydrogen saturates broken bonds along Si{l_brace}111{r_brace} Type 1 glide planes (one bond per Si atom) and along Si{l_brace}111{r_brace} Type II glide planes (three bonds per Si atom). The Si-H peak area indicates a H areal density {approximately}2 times higher than in very lightly doped Si.

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

    NASA Astrophysics Data System (ADS)

    Wang, B. B.; Zheng, K.; Cheng, Q. J.; Ostrikov, K.

    2015-01-01

    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.

  18. Observations of Low-Latitude Plasma Density Enhancements and their Associated Plasma Drifts

    NASA Technical Reports Server (NTRS)

    Klenzing, J. H.; Rowland, D. E.; Pfaff, R. F.; Le, G.; Freudenreich, H.; Haaser, R. A.; Burrell, A. G.; Stoneback, R. A.; Coley, W. R.; Heelis, R. A.

    2011-01-01

    Plasma density structures are frequently encountered in the nighttime low-latitude ionosphere by probes on the Communication/Navigation Outage Forecasting System (C/NOFS) satellite. Of particular interest to us here are plasma density enhancements, which are typically observed +/- 15 deg away from the magnetic equator. The low inclination of the C/NOFS satellite offers an unprecedented opportunity to examine these structures and their associated electric fields and plasma velocities, including their field-aligned components, along an east-west trajectory. Among other observations, the data reveal a clear asymmetry in the velocity structure within and around these density enhancements. Previous observations have shown that the peak change in drift velocity associated with a density enhancement occurs simultaneously both perpendicular and parallel to the magnetic field, while the 1results in this paper show that the peak change in parallel fl ow typically occurs 25-100 km to the east of the peak perpendicular ow. We discuss this and other aspects of the observations in relation to the characteristics of the plasma depletions formed near the magnetic equator detected by the same probes on the C/NOFS satellite and to previous observations and theories.

  19. Enhanced plasma current collection from weakly conducting solar array blankets

    NASA Technical Reports Server (NTRS)

    Hillard, G. Barry

    1993-01-01

    Among the solar cell technologies to be tested in space as part of the Solar Array Module Plasma Interactions Experiment (SAMPIE) will be the Advanced Photovoltaic Solar Array (APSA). Several prototype twelve cell coupons were built for NASA using different blanket materials and mounting techniques. The first conforms to the baseline design for APSA which calls for the cells to be mounted on a carbon loaded Kapton blanket to control charging in GEO. When deployed, this design has a flexible blanket supported around the edges. A second coupon was built with the cells mounted on Kapton-H, which was in turn cemented to a solid aluminum substrate. A final coupon was identical to the latter but used germanium coated Kapton to control atomic oxygen attack in LEO. Ground testing of these coupons in a plasma chamber showed considerable differences in plasma current collection. The Kapton-H coupon demonstrated current collection consistent with exposed interconnects and some degree of cell snapover. The other two coupons experienced anomalously large collection currents. This behavior is believed to be a consequence of enhanced plasma sheaths supported by the weakly conducting carbon and germanium used in these coupons. The results reported here are the first experimental evidence that the use of such materials can result in power losses to high voltage space power systems.

  20. Enhanced plasma current collection from weakly conducting solar array blankets

    NASA Astrophysics Data System (ADS)

    Hillard, G. Barry

    1993-05-01

    Among the solar cell technologies to be tested in space as part of the Solar Array Module Plasma Interactions Experiment (SAMPIE) will be the Advanced Photovoltaic Solar Array (APSA). Several prototype twelve cell coupons were built for NASA using different blanket materials and mounting techniques. The first conforms to the baseline design for APSA which calls for the cells to be mounted on a carbon loaded Kapton blanket to control charging in GEO. When deployed, this design has a flexible blanket supported around the edges. A second coupon was built with the cells mounted on Kapton-H, which was in turn cemented to a solid aluminum substrate. A final coupon was identical to the latter but used germanium coated Kapton to control atomic oxygen attack in LEO. Ground testing of these coupons in a plasma chamber showed considerable differences in plasma current collection. The Kapton-H coupon demonstrated current collection consistent with exposed interconnects and some degree of cell snapover. The other two coupons experienced anomalously large collection currents. This behavior is believed to be a consequence of enhanced plasma sheaths supported by the weakly conducting carbon and germanium used in these coupons. The results reported here are the first experimental evidence that the use of such materials can result in power losses to high voltage space power systems.

  1. Enhanced remote earthquake triggering at fluid-injection sites in the midwestern United States.

    PubMed

    van der Elst, Nicholas J; Savage, Heather M; Keranen, Katie M; Abers, Geoffrey A

    2013-07-12

    A recent dramatic increase in seismicity in the midwestern United States may be related to increases in deep wastewater injection. Here, we demonstrate that areas with suspected anthropogenic earthquakes are also more susceptible to earthquake-triggering from natural transient stresses generated by the seismic waves of large remote earthquakes. Enhanced triggering susceptibility suggests the presence of critically loaded faults and potentially high fluid pressures. Sensitivity to remote triggering is most clearly seen in sites with a long delay between the start of injection and the onset of seismicity and in regions that went on to host moderate magnitude earthquakes within 6 to 20 months. Triggering in induced seismic zones could therefore be an indicator that fluid injection has brought the fault system to a critical state. PMID:23846900

  2. Enhancing the Teaching of Digital Processing of Remote Sensing Image Course through Geospatial Web Processing Services

    NASA Astrophysics Data System (ADS)

    di, L.; Deng, M.

    2010-12-01

    Remote sensing (RS) is an essential method to collect data for Earth science research. Huge amount of remote sensing data, most of them in the image form, have been acquired. Almost all geography departments in the world offer courses in digital processing of remote sensing images. Such courses place emphasis on how to digitally process large amount of multi-source images for solving real world problems. However, due to the diversity and complexity of RS images and the shortcomings of current data and processing infrastructure, obstacles for effectively teaching such courses still remain. The major obstacles include 1) difficulties in finding, accessing, integrating and using massive RS images by students and educators, and 2) inadequate processing functions and computing facilities for students to freely explore the massive data. Recent development in geospatial Web processing service systems, which make massive data, computing powers, and processing capabilities to average Internet users anywhere in the world, promises the removal of the obstacles. The GeoBrain system developed by CSISS is an example of such systems. All functions available in GRASS Open Source GIS have been implemented as Web services in GeoBrain. Petabytes of remote sensing images in NASA data centers, the USGS Landsat data archive, and NOAA CLASS are accessible transparently and processable through GeoBrain. The GeoBrain system is operated on a high performance cluster server with large disk storage and fast Internet connection. All GeoBrain capabilities can be accessed by any Internet-connected Web browser. Dozens of universities have used GeoBrain as an ideal platform to support data-intensive remote sensing education. This presentation gives a specific example of using GeoBrain geoprocessing services to enhance the teaching of GGS 588, Digital Remote Sensing taught at the Department of Geography and Geoinformation Science, George Mason University. The course uses the textbook "Introductory

  3. Enhanced current flow through a plasma cloud by induction of plasma turbulence

    NASA Technical Reports Server (NTRS)

    Hastings, D. E.

    1987-01-01

    Electrodynamic tethers have been proposed as a means of generating power in low earth orbit. One of the limitations on the power generated is the relatively low electron current that can be collected. It is proposed that the electron current can be significantly enhanced by means of current-induced plasma turbulence in a plasma cloud around the collecting anode. This is examined for the specific case of ion acoustic turbulence. An important conclusion is that the use of plasma clouds in the ionosphere will entail a high-impedance (no instability) and a low-impedance (ion acoustic instability) mode of operation. The low-impedance mode of operation will have two submodes, one steady state and one pulsed.

  4. Enhanced Discharge Performance in a Ring Cusp Plasma Source

    NASA Technical Reports Server (NTRS)

    Foster, John E.; Patterson, Michael J.

    2000-01-01

    There is a need for a lightweight, low power ion thruster for space science missions. Such an ion thruster is under development at NASA Glenn Research Center. In an effort to better understand the discharge performance of this thruster, a thruster discharge chamber with an anode containing electrically isolated electrodes at the cusps was fabricated and tested. Characteristics of this ring cusp ion discharge were measured without ion beam extraction. Discharge current was measured at collection electrodes located at the magnetic cusps and at the anode body itself. Discharge performance and plasma properties were measured as a function of power, which was varied between 20 and 50 W. It was found that ion production costs decreased by as much as 20 percent when the two most downstream cusp electrodes were allowed to float. Floating the electrodes did not give rise to a significant increase in discharge power even though the plasma density increased markedly. The improved performance is attributed to enhanced electron containment.

  5. Enhancing Laser Induced Plasma Emissions using Various Excitation Modalities

    NASA Astrophysics Data System (ADS)

    Johnson, Lewis; Akpovo, Charlemagne; Gebreegziabher, Samson; Martinez, Jorge, Jr.

    2008-11-01

    Detection of hazardous materials with Laser Induced Breakdown Spectroscopy (LIBS) requires a detailed understanding of the sample matrix as well as the surrounding environment. We report on our efforts to understand and manipulate the continuum and atmospheric levels while enhancing surface and substrate material identifications. Comparisons are made between: single pulse (SP) nanosecond (ns); SP femtosecond (fs); SP fs-self-channeled (fs-sc); Dual pulse (DP) ns; DP ns -- fs; and DP ns fs-sc; and multi--pulse Continuous Wave (CW) plasmas formed on the sample surface. Plasma emission spectra from atmospheric oxygen and nitrogen, as well as aluminum and Copper substrates, and hazardous oxygen and nitrogen rich materials residues are analyzed.

  6. Exploring the Human Plasma Proteome for Humoral Mediators of Remote Ischemic Preconditioning - A Word of Caution

    PubMed Central

    Helgeland, Erik; Breivik, Lars Ertesvåg; Vaudel, Marc; Svendsen, Øyvind Sverre; Garberg, Hilde; Nordrehaug, Jan Erik; Berven, Frode Steingrimsen; Jonassen, Anne Kristine

    2014-01-01

    Despite major advances in early revascularization techniques, cardiovascular diseases are still the leading cause of death worldwide, and myocardial infarctions contribute heavily to this. Over the past decades, it has become apparent that reperfusion of blood to a previously ischemic area of the heart causes damage in and of itself, and that this ischemia reperfusion induced injury can be reduced by up to 50% by mechanical manipulation of the blood flow to the heart. The recent discovery of remote ischemic preconditioning (RIPC) provides a non-invasive approach of inducing this cardioprotection at a distance. Finding its endogenous mediators and their operative mode is an important step toward increasing the ischemic tolerance. The release of humoral factor(s) upon RIPC was recently demonstrated and several candidate proteins were published as possible mediators of the cardioprotection. Before clinical applicability, these potential biomarkers and their efficiency must be validated, a task made challenging by the large heterogeneity in reported data and results. Here, in an attempt to reproduce and provide more experimental data on these mediators, we conducted an unbiased in-depth analysis of the human plasma proteome before and after RIPC. From the 68 protein markers reported in the literature, only 28 could be mapped to manually reviewed (Swiss-Prot) protein sequences. 23 of them were monitored in our untargeted experiment. However, their significant regulation could not be reproducibly estimated. In fact, among the 394 plasma proteins we accurately quantified, no significant regulation could be confidently and reproducibly assessed. This indicates that it is difficult to both monitor and reproduce published data from experiments exploring for RIPC induced plasma proteomic regulations, and suggests that further work should be directed towards small humoral factors. To simplify this task, we made our proteomic dataset available via ProteomeXchange, where

  7. Zanamivir Oral Delivery: Enhanced Plasma and Lung Bioavailability in Rats

    PubMed Central

    Shanmugam, Srinivasan; Im, Ho Taek; Sohn, Young Taek; Kim, Kyung Soo; Kim, Yong- Il; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon; Woo, Jong Soo

    2013-01-01

    The objective of this study was to enhance the oral bioavailability (BA) of zanamivir (ZMR) by increasing its intestinal permeability using permeation enhancers (PE). Four different classes of PEs (Labrasol®, sodium cholate, sodium caprate, hydroxypropyl β-cyclodextrin) were investigated for their ability to enhance the permeation of ZMR across Caco-2 cell monolayers. The flux and Papp of ZMR in the presence of sodium caprate (SC) was significantly higher than other PEs in comparison to control, and was selected for further investigation. All concentrations of SC (10-200 mM) demonstrated enhanced flux of ZMR in comparison to control. The highest flux (13 folds higher than control) was achieved for the formulation with highest SC concentration (200 mM). The relative BA of ZMR formulation containing SC (PO-SC) in plasma at a dose of 10 mg/kg following oral administration in rats was 317.65% in comparison to control formulation (PO-C). Besides, the AUC0-24 h of ZMR in the lungs following oral administration of PO-SC was 125.22 ± 27.25 ng hr ml-1 with a Cmax of 156.00 ± 24.00 ng/ml reached at 0.50±0.00 h. But, there was no ZMR detected in the lungs following administration of control formulation (PO-C). The findings of this study indicated that the oral formulation PO-SC containing ZMR and SC was able to enhance the BA of ZMR in plasma to an appropriate amount that would make ZMR available in lungs at a concentration higher (>10 ng/ml) than the IC50 concentration of influenza virus (0.64-7.9 ng/ml) to exert its therapeutic effect. PMID:24009875

  8. Plasma-enhanced chemical vapor deposition of multiwalled carbon nanofibers

    NASA Technical Reports Server (NTRS)

    Matthews, Kristopher; Cruden, Brett A.; Chen, Bin; Meyyappan, M.; Delzeit, Lance

    2002-01-01

    Plasma-enhanced chemical vapor deposition is used to grow vertically aligned multiwalled carbon nanofibers (MWNFs). The graphite basal planes in these nanofibers are not parallel as in nanotubes; instead they exhibit a small angle resembling a stacked cone arrangement. A parametric study with varying process parameters such as growth temperature, feedstock composition, and substrate power has been conducted, and these parameters are found to influence the growth rate, diameter, and morphology. The well-aligned MWNFs are suitable for fabricating electrode systems in sensor and device development.

  9. Deletion of a remote enhancer near ATOH7 disrupts retinal neurogenesis, causing NCRNA disease

    PubMed Central

    Ghiasvand, Noor M.; Rudolph, Dellaney D.; Mashayekhi, Mohammad; Brzezinski, Joseph A.; Goldman, Daniel; Glaser, Tom

    2011-01-01

    Individuals with nonsyndromic congenital retinal nonattachment (NCRNA) are totally blind from birth. The disease afflicts ~1% of Kurdish people living in a group of neighboring villages in North Khorasan, Iran. We show NCRNA is caused by a 6523bp deletion that spans a remote cis regulatory element 20 kb upstream from ATOH7 (Math5), a bHLH transcription factor gene required for retinal ganglion cell (RGC) and optic nerve development. In humans, the absence of RGCs stimulates massive neovascular growth of fetal blood vessels within the vitreous, and early retinal detachment. The remote ATOH7 element appears to act as a secondary or ‘shadow’ transcriptional enhancer. It has minimal sequence similarity to the primary enhancer, which is close to the Atoh7 promoter, but drives transgene expression with an identical spatiotemporal pattern in the mouse retina. The human transgene also functions in zebrafish, reflecting deep evolutionary conservation. These dual enhancers may reinforce Atoh7 expression during early critical stages of eye development when retinal neurogenesis is initiated. PMID:21441919

  10. Enhanced remote earthquake triggering at fluid injection sites in the Midwestern U.S

    NASA Astrophysics Data System (ADS)

    van der Elst, N.; Savage, H. M.; Keranen, K. M.; Abers, G. A.

    2013-12-01

    A dramatic increase in seismicity in the Midwestern United States may be related to increased deep wastewater injection. We systematically examined sites of potential anthropogenic seismicity for evidence of remote earthquake triggering, which could indicate high fluid pressure and critically stressed faults. Using a cross-correlation method to enhance earthquake catalogs for individual TA stations, we found that regions of anthropogenic seismicity are also susceptible to earthquake triggering from natural transient stresses carried by seismic waves of large remote earthquakes. We detected triggered earthquakes following the three largest dynamic strain events since 2010, showing triggering by the 2010 Mw 8.8 Maule, Chile, earthquake at Prague, OK, and Trinidad, CO, and triggering by the 2011 Mw 9.1 Tohoku-Oki earthquake at Snyder, TX. Each of these sites hosted larger earthquakes (Mw 4.5-5.7) within the next 6 to 20 months. Enhanced triggering susceptibility could therefore be an advance indicator that fluid injection has brought the regional fault system to a critical state. Remote triggering is strongest at sites where the onset of seismicity lagged injection by many years, and where high swarm activity had not yet begun. The sites that triggered during the 2010 Chile earthquake did not trigger in the subsequent 2011 Tohoku earthquake, which suggests the importance of local conditions or a long recharge period for the triggering mechanism. By analogy with natural dynamic triggering at hydrothermal sites, we invoke a mechanism involving fracture unclogging or dynamic permeability enhancement, in which the seismic waves alter subsurface fluid flow and accelerate pressure changes on already critically stressed faults.

  11. Interactive Computer-Enhanced Remote Viewing System (ICERVS): Final report, November 1994--September 1996

    SciTech Connect

    1997-05-01

    The Interactive Computer-Enhanced Remote Viewing System (ICERVS) is a software tool for complex three-dimensional (3-D) visualization and modeling. Its primary purpose is to facilitate the use of robotic and telerobotic systems in remote and/or hazardous environments, where spatial information is provided by 3-D mapping sensors. ICERVS provides a robust, interactive system for viewing sensor data in 3-D and combines this with interactive geometric modeling capabilities that allow an operator to construct CAD models to match the remote environment. Part I of this report traces the development of ICERVS through three evolutionary phases: (1) development of first-generation software to render orthogonal view displays and wireframe models; (2) expansion of this software to include interactive viewpoint control, surface-shaded graphics, material (scalar and nonscalar) property data, cut/slice planes, color and visibility mapping, and generalized object models; (3) demonstration of ICERVS as a tool for the remediation of underground storage tanks (USTs) and the dismantlement of contaminated processing facilities. Part II of this report details the software design of ICERVS, with particular emphasis on its object-oriented architecture and user interface.

  12. Remote excitation-tip-enhanced Raman scattering microscopy using silver nanowire

    NASA Astrophysics Data System (ADS)

    Fujita, Yasuhiko; Walke, Peter; De Feyter, Steven; Uji-i, Hiroshi

    2016-08-01

    Tip-enhanced Raman scattering (TERS) microscopy is a promising technique for use in surface analysis, allowing both topographic and spectroscopic information to be obtained simultaneously at a scale below 10 nm. One proposed method to further improve spatial resolution is the use of propagating surface plasmons as an excitation light source (i.e., remote excitation). However, this requires a specialized tip that can only be fabricated via expensive procedures, such as electron-beam lithography. Here, we propose a new method for fabricating silver nanowire-based tips that are suitable for remote excitation-TERS, removing the need for such techniques. A silver nanowire was fixed onto a tungsten-tip using a micromanipulator, before gold nanoparticles were attached in a site-specific manner using AC-dielectrophoresis. All the processes were completed using an optical microscope in the ambient. The background intensities in TERS spectra were suppressed with remote excitation relative to the conventional excitation configuration, indicating an increase in TERS sensitivity.

  13. Modeling and Simulation of Plasma Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Smith, Aaron; Bett, Dominic; Cunningham, Monisha; Sen, Sudip

    2015-04-01

    Plasma Enhanced Chemical Vapor Deposition (PECVD) is a process used to deposit thin films from a gas state (vapor) to a solid state on a substrate. Recent study from the X-ray diffraction spectra of SnO2 films deposited as a function of RF power apparently indicates that RF power is playing a stabilizing role and hence in the better deposition. The results show that the RF power results in smoother morphology, improved crystallinity, and lower sheet resistance value in the PECVD process. The PECVD processing allows deposition at lower temperatures, which is often critical in the manufacture of semiconductors. In this talk we will address two aspects of the problem, first to develop a model to study the mechanism of how the PECVD is effected by the RF power, and second to actually simulate the effect of RF power on PECVD. As the PECVD is a very important component of the plasma processing technology with many applications in the semiconductor technology and surface science, the research proposed here has the prospect to revolutionize the plasma processing technology through the stabilizing role of the RF power.

  14. Carbon Nanotubes/Nanofibers by Plasma Enhanced Chemical Vapour Deposition

    NASA Technical Reports Server (NTRS)

    Teo, K. B. K.; Hash, D. B.; Bell, M. S.; Chhowalla, M.; Cruden, B. A.; Amaratunga, G. A. J.; Meyyappan, M.; Milne, W. I.

    2005-01-01

    Plasma enhanced chemical vapour deposition (PECVD) has been recently used for the production of vertically aligned carbon nanotubedfibers (CN) directly on substrates. These structures are potentially important technologically as electron field emitters (e.g. microguns, microwave amplifiers, displays), nanoelectrodes for sensors, filter media, superhydrophobic surfaces and thermal interface materials for microelectronics. A parametric study on the growth of CN grown by glow discharge dc-PECVD is presented. In this technique, a substrate containing thin film Ni catalyst is exposed to C2H2 and NH3 gases at 700 C. Without plasma, this process is essentially thermal CVD which produces curly spaghetti-like CN as seen in Fig. 1 (a). With the plasma generated by biasing the substrate at -6OOV, we observed that the CN align vertically during growth as shown in Fig. l(b), and that the magnitude of the applied substrate bias affects the degree of alignment. The thickness of the thin film Ni catalyst was found to determine the average diameter and inversely the length of the CN. The yield and density of the CN were controlled by the use of different diffusion barrier materials under the Ni catalyst. Patterned CN growth [Fig. l(c)], with la variation in CN diameter of 4.1% and 6.3% respectively, is achieved by lithographically defining the Ni thin film prior to growth. The shape of the structures could be varied from very straight nanotube-like to conical tip-like nanofibers by increasing the ratio of C2H2 in the gas flow. Due to the plasma decomposition of C2H2, amorphous carbon (a-C) is an undesirable byproduct which could coat the substrate during CN growth. Using a combination of depth profiled Auger electron spectroscopy to study the substrate and in-situ mass spectroscopy to examine gas phase neutrals and ions, the optimal conditions for a-C free growth of CN is determined.

  15. Remote atmospheric-pressure plasma activation of the surfaces of polyethylene terephthalate and polyethylene naphthalate.

    PubMed

    Gonzalez, E; Barankin, M D; Guschl, P C; Hicks, R F

    2008-11-01

    The surfaces of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) were treated with an atmospheric-pressure oxygen and helium plasma. Changes in the energy, adhesion, and chemical composition of the surfaces were determined by contact angle measurements, mechanical pull tests, and X-ray photoelectron spectroscopy (XPS). Surface-energy calculations revealed that after plasma treatment the polarity of PET and PEN increased 6 and 10 times, respectively. In addition, adhesive bond strengths were enhanced by up to 7 times. For PET and PEN, XPS revealed an 18-29% decrease in the area of the C 1s peak at 285 eV, which is attributable to the aromatic carbon atoms. The C 1s peak area due to ester carbon atoms increased by 11 and 24% for PET and PEN, respectively, while the C 1s peak area resulting from C-O species increased by about 5% for both polymers. These results indicate that oxygen atoms generated in the plasma rapidly oxidize the aromatic rings on the polymer chains. The Langmuir adsorption rate constants for oxidizing the polymer surfaces were 15.6 and 4.6 s(-1) for PET and PEN, respectively. PMID:18834154

  16. GPs with enhanced surgical skills: a questionable solution for remote surgical services

    PubMed Central

    Vinden, Christopher; Ott, Michael C.

    2015-01-01

    Summary The Canadian College of Family Physicians recently decided to recognize family physicians with enhanced surgical skills (ESS) and has proposed a 1-year curriculum of surgical training. The purpose of this initiative is to bring or enhance surgical services to remote and underserviced areas. We feel that this proposed curriculum is overly ambitious and unrealistic and that it is unlikely to produce surgeons, or a system, capable of delivering high-quality surgical services. The convergence of a new training curriculum for general surgeons, coupled with the current oversupply of surgeons, provide an alternate pathway to meet the needs of these communities. A long-term solution will also require alternate funding models, a sophisticated and coordinated national locum service and a national review of the population and infrastructure requirements necessary for both sustainable resident surgical services and surgical outreach services. PMID:26574827

  17. Novel atmospheric plasma enhanced chitosan nanofiber/gauze composite wound dressings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electrospun chitosan nanofibers were deposited onto atmospheric plasma treated cotton gauze to create a novel composite bandage with higher adhesion, better handling properties, enhanced bioactivity, and moisture management. Plasma treatment of the gauze substrate was performed to improve the durabi...

  18. Evolution of plasma parameters in a He - N2/Ar magnetic pole enhanced inductive plasma source

    NASA Astrophysics Data System (ADS)

    Younus, Maria; Rehman, N. U.; Shafiq, M.; Zakaullah, M.; Abrar, M.

    2016-02-01

    A magnetic pole enhanced inductively coupled H e - N2/A r plasma is studied at low pressure, to monitor the effects of helium mixing on plasma parameters like electron number density (ne) , electron temperature (Te) , plasma potential (Vp ) , and electron energy probability functions (EEPFs). An RF compensated Langmuir probe is employed to measure these plasma parameters. It is noted that electron number density increases with increasing RF power and helium concentration in the mixture, while it decreases with increase in filling gas pressure. On the other hand, electron temperature shows an increasing trend with helium concentration in the mixture. At low RF powers and low helium concentration in the mixture, EEPFs show a "bi-Maxwellian" distribution with pressure. While at RF powers greater than 50 W and higher helium concentration in the mixture, EEPFs evolve into "Maxwellian" distribution. The variation of skin depth with RF power and helium concentration in the mixture, and its relation with EEPF are also studied. The effect of helium concentrations on the temperatures of two electron groups ( Tb u l k and Tt a i l ) in the "bi-Maxwellian" EEPFs is also observed. The temperature of low energy electron group ( Tb u l k) shows significant increase with helium addition, while the temperature of tail electrons ( Tt a i l) increases smoothly as compared to ( Tb u l k).

  19. Plasma-enhanced synthesis of green flame retardant cellulosic materials

    NASA Astrophysics Data System (ADS)

    Totolin, Vladimir

    The natural fiber-containing fabrics and composites are more environmentally friendly, and are used in transportation (automobiles, aerospace), military applications, construction industries (ceiling paneling, partition boards), consumer products, etc. Therefore, the flammability characteristics of the composites based on polymers and natural fibers play an important role. This dissertation presents the development of plasma assisted - green flame retardant coatings for cellulosic substrates. The overall objective of this work was to generate durable flame retardant treatment on cellulosic materials. In the first approach sodium silicate layers were pre-deposited onto clean cotton substrates and cross linked using low pressure, non-equilibrium oxygen plasma. A statistical design of experiments was used to optimize the plasma parameters. The modified cotton samples were tested for flammability using an automatic 45° angle flammability test chamber. Aging tests were conducted to evaluate the coating resistance during the accelerated laundry technique. The samples revealed a high flame retardant behavior and good thermal stability proved by thermo-gravimetric analysis. In the second approach flame retardant cellulosic materials have been produced using a silicon dioxide (SiO2) network coating. SiO 2 network armor was prepared through hydrolysis and condensation of the precursor tetraethyl orthosilicate (TEOS), prior coating the substrates, and was cross linked on the surface of the substrates using atmospheric pressure plasma (APP) technique. Due to protection effects of the SiO2 network armor, the cellulosic based fibers exhibit enhanced thermal properties and improved flame retardancy. In the third approach, the TEOS/APP treatments were extended to linen fabrics. The thermal analysis showed a higher char content and a strong endothermic process of the treated samples compared with control ones, indicating a good thermal stability. Also, the surface analysis proved

  20. Growth of graphene films by plasma enhanced chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Baraton, Laurent; Gangloff, Laurent; Xavier, Stéphane; Cojocaru, Costel S.; Huc, Vincent; Legagneux, Pierre; Lee, Young Hee; Pribat, Didier

    2009-08-01

    Since it was isolated in 2004, graphene, the first known 2D crystal, is the object of a growing interest, due to the range of its possible applications as well as its intrinsic properties. From large scale electronics and photovoltaics to spintronics and fundamental quantum phenomena, graphene films have attracted a large community of researchers. But bringing graphene to industrial applications will require a reliable, low cost and easily scalable synthesis process. In this paper we present a new growth process based on plasma enhanced chemical vapor deposition. Furthermore, we show that, when the substrate is an oxidized silicon wafer covered by a nickel thin film, graphene is formed not only on top of the nickel film, but also at the interface with the supporting SiO2 layer. The films grown using this method were characterized using classical methods (Raman spectroscopy, AFM, SEM) and their conductivity is found to be close to those reported by others.

  1. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Li, J.; Ye, Q.; Koehne, J.; Chen, H.; Meyyappan, M.

    2004-01-01

    The multitude of considerations facing nanostructure growth and integration lends itself to combinatorial optimization approaches. Rapid optimization becomes even more important with wafer-scale growth and integration processes. Here we discuss methodology for developing plasma enhanced CVD growth techniques for achieving individual, vertically aligned carbon nanostructures that show excellent properties as ultrasensitive electrodes for nucleic acid detection. We utilize high throughput strategies for optimizing the upstream and downstream processing and integration of carbon nanotube electrodes as functional elements in various device types. An overview of ultrasensitive carbon nanotube based sensor arrays for electrochemical biosensing applications and the high throughput methodology utilized to combine novel electrode technology with conventional MEMS processing will be presented.

  2. Plasma Enhanced Growth of Carbon Nanotubes For Ultrasensitive Biosensors

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Meyyappan, M.

    2004-01-01

    The multitude of considerations facing nanostructure growth and integration lends itself to combinatorial optimization approaches. Rapid optimization becomes even more important with wafer-scale growth and integration processes. Here we discuss methodology for developing plasma enhanced CVD growth techniques for achieving individual, vertically aligned carbon nanostructures that show excellent properties as ultrasensitive electrodes for nucleic acid detection. We utilize high throughput strategies for optimizing the upstream and downstream processing and integration of carbon nanotube electrodes as functional elements in various device types. An overview of ultrasensitive carbon nanotube based sensor arrays for electrochemical bio-sensing applications and the high throughput methodology utilized to combine novel electrode technology with conventional MEMS processing will be presented.

  3. Plasma-Sprayed Titanium Patterns for Enhancing Early Cell Responses

    NASA Astrophysics Data System (ADS)

    Shi, Yunqi; Xie, Youtao; Pan, Houhua; Zheng, Xuebin; Huang, Liping; Ji, Fang; Li, Kai

    2016-06-01

    Titanium coating has been widely used as a biocompatible metal in biomedical applications. However, the early cell responses and long-term fixation of titanium implants are not satisfied. To obviate these defects, in this paper, micro-post arrays with various widths (150-1000 μm) and intervals (100-300 μm) were fabricated on the titanium substrate by template-assisted plasma spraying technology. In vitro cell culture experiments showed that MC3T3-E1 cells exhibited significantly higher osteogenic differentiation as well as slightly improved adhesion and proliferation on the micro-patterned coatings compared with the traditional one. The cell number on the pattern with 1000 µm width reached 130% after 6 days of incubation, and the expressions of osteopontin (OPN) as well as osteocalcin (OC) were doubled. No obvious difference was found in cell adhesion on various size patterns. The present micro-patterned coatings proposed a new modification method for the traditional plasma spraying technology to enhance the early cell responses and convenience for the bone in-growth.

  4. Plasma enhanced atomic layer deposition of ultrathin oxides on graphene

    NASA Astrophysics Data System (ADS)

    Trimble, Christie J.; Zaniewski, Anna M.; Kaur, Manpuneet; Nemanich, Robert J.

    2015-03-01

    Graphene, a single atomic layer of sp2 bonded carbon atoms, possesses extreme material properties that point toward a plethora of potential electronic applications. Many of these possibilities require the combination of graphene with dielectric materials such as metal oxides. Simultaneously, there is interest in new physical properties that emerge when traditionally three dimensional materials are constrained to ultrathin layers. For both of these objectives, we explore deposition of ultrathin oxide layers on graphene. In this project, we perform plasma enhanced atomic layer deposition (PEALD) of aluminum oxide on graphene that has been grown by chemical vapor deposition atop copper foil and achieve oxide layers that are <1.5 nm. Because exposure to oxygen plasma can cause the graphene to deteriorate, we explore techniques to mitigate this effect and optimize the PEALD process. Following deposition, the graphene and oxide films are transferred to arbitrary substrates for further analysis. We use x-ray photoelectron spectroscopy, Raman spectroscopy, and atomic force microscopy to assess the quality of the resulting films. This work is supported by the National Science Foundation under Grant # DMR-1206935.

  5. Mercury's Plasma Mantle during Solar Wind Dynamical Pressure Enhancements

    NASA Astrophysics Data System (ADS)

    Delcourt, D.; Seki, K.; Terada, N.; Moore, T. E.

    2014-12-01

    Because of the weak planetary magnetic field as well as proximity to the Sun, the magnetosphere of Mercury is very dynamical and at times subjected to prominent compression. Recent observations from MESSENGER reveal that during events of enhanced solar wind dynamical pressure, the subsolar magnetopause may actually be pushed until the immediate vicinity of the planet surface. Using three-dimensional single-particle simulations, we examine the dynamics of solar wind originating protons during such events. We show that these impulsive events can lead to substantial (several hundreds of eVs or a few keVs) H+ energization in the plasma mantle. Unlike ions with large mass-to-charge ratios (e.g., Na+ of planetary origin), H+ are transported adiabatically during these events, their energization being due to the ExB convection surge. MESSENGER observations of the plasma mantle show repeated evidences of such a transient H+ energization which may follow from the variable character of Mercury's magnetosphere.

  6. Plasma-Sprayed Titanium Patterns for Enhancing Early Cell Responses

    NASA Astrophysics Data System (ADS)

    Shi, Yunqi; Xie, Youtao; Pan, Houhua; Zheng, Xuebin; Huang, Liping; Ji, Fang; Li, Kai

    2016-05-01

    Titanium coating has been widely used as a biocompatible metal in biomedical applications. However, the early cell responses and long-term fixation of titanium implants are not satisfied. To obviate these defects, in this paper, micro-post arrays with various widths (150-1000 μm) and intervals (100-300 μm) were fabricated on the titanium substrate by template-assisted plasma spraying technology. In vitro cell culture experiments showed that MC3T3-E1 cells exhibited significantly higher osteogenic differentiation as well as slightly improved adhesion and proliferation on the micro-patterned coatings compared with the traditional one. The cell number on the pattern with 1000 µm width reached 130% after 6 days of incubation, and the expressions of osteopontin (OPN) as well as osteocalcin (OC) were doubled. No obvious difference was found in cell adhesion on various size patterns. The present micro-patterned coatings proposed a new modification method for the traditional plasma spraying technology to enhance the early cell responses and convenience for the bone in-growth.

  7. Remote sensing for archaeological site reconnaissance : the role of edge detection and enhancement

    NASA Astrophysics Data System (ADS)

    Masini, N.; Lasaponara, R.

    2012-04-01

    The reconnaissance of features of archaeological interest represents one of the most intriguing challenges of remote sensing applied to cultural heritage. The rate of success of site discovery depends on several factors such as: i) the availability of a rich data set from archaeological record to remotely sensed image; ii) the capability of sensors; iii) the knowledge of physical and chemical phenomenology linked to the presence of archaeological deposits; iv) the selection and the use of effective edge detection and extraction methods. The latter is the focus of this work which aims at assessing different image processing methods for the enhancement, detection and extraction of edges of archaeological features, such as convolution, image fusion, wavelet, local spatial autocorrelation. The test sites cover different surface characteristics (from bare to vegetated soil), archaeological features (buried, shallow and surface archaeological features) and markers(crop and soil marks, microrelief) Reference Lasaponara R., Masini N. 2007, Detection of archaeological crop marks by using satellite QuickBird, Journal of Archaeological Science, 34, pp. 214-221 doi: 10.1016/j.jas.2006.04.014 Masini N., Lasaponara R. 2007, Investigating the spectral capability of QuickBird data to detect archaeological remains buried under vegetated and not vegetated areas , Journal of Cultural Heritage, 8 (1), pp. 53-60, Doi : 10.1016/j.culher.2006.06.006 Lasaponara R., Masini N. 2011, Satellite Remote Sensing in Archaeology : past, present and future, Journal of Archaeological Science, 38(9), 1995-2002, doi:10.1016/j.jas.2011.02.002

  8. Mechanism of Growth Enhancement of Plants Induced by Active Species in Plasmas

    NASA Astrophysics Data System (ADS)

    Watanabe, Satoshi; Ono, Reoto; Hayashi, Nobuya

    2015-09-01

    Plant growth enhances when seeds are irradiated by plasma. However the mechanism of the growth enhancement by plasma has not been clarified. In this study, growth enhancement of plants using various active species and variation of plant cells are investigated. RF plasma is generated under conditions where pressure is 60 Pa and input electrical power is 60 W. Irradiation period varies from 0 (control) to 75 min. Air plasma shows maximum growth of plants with irradiation period of 60 min on the other hand, oxygen plasma shows the maximum growth with irradiation period of 15 min. From change of gaseous species and pressure dependence, growth enhancing factor is expected to be active oxygen species produced in plasma. According to gene expression analysis of Arabidopsis, there are two speculated mechanism of plant growth enhancement. The first is acceleration of cell cycle by gene expressions of photosynthesis and glycolytic pathway, and the second is increase of cell size via plant hormone production.

  9. Hyperspectral Remote Sensing and Ecological Modeling Research and Education at Mid America Remote Sensing Center (MARC): Field and Laboratory Enhancement

    NASA Technical Reports Server (NTRS)

    Cetin, Haluk

    1999-01-01

    The purpose of this project was to establish a new hyperspectral remote sensing laboratory at the Mid-America Remote sensing Center (MARC), dedicated to in situ and laboratory measurements of environmental samples and to the manipulation, analysis, and storage of remotely sensed data for environmental monitoring and research in ecological modeling using hyperspectral remote sensing at MARC, one of three research facilities of the Center of Reservoir Research at Murray State University (MSU), a Kentucky Commonwealth Center of Excellence. The equipment purchased, a FieldSpec FR portable spectroradiometer and peripherals, and ENVI hyperspectral data processing software, allowed MARC to provide hands-on experience, education, and training for the students of the Department of Geosciences in quantitative remote sensing using hyperspectral data, Geographic Information System (GIS), digital image processing (DIP), computer, geological and geophysical mapping; to provide field support to the researchers and students collecting in situ and laboratory measurements of environmental data; to create a spectral library of the cover types and to establish a World Wide Web server to provide the spectral library to other academic, state and Federal institutions. Much of the research will soon be published in scientific journals. A World Wide Web page has been created at the web site of MARC. Results of this project are grouped in two categories, education and research accomplishments. The Principal Investigator (PI) modified remote sensing and DIP courses to introduce students to ii situ field spectra and laboratory remote sensing studies for environmental monitoring in the region by using the new equipment in the courses. The PI collected in situ measurements using the spectroradiometer for the ER-2 mission to Puerto Rico project for the Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS). Currently MARC is mapping water quality in Kentucky Lake and

  10. Growth Enhancement of Radish Sprouts Induced by Low Pressure O2 Radio Frequency Discharge Plasma Irradiation

    NASA Astrophysics Data System (ADS)

    Kitazaki, Satoshi; Koga, Kazunori; Shiratani, Masaharu; Hayashi, Nobuya

    2012-01-01

    We studied growth enhancement of radish sprouts (Raphanus sativus L.) induced by low pressure O2 radio frequency (RF) discharge plasma irradiation. The average length of radish sprouts cultivated for 7 days after O2 plasma irradiation is 30-60% greater than that without irradiation. O2 plasma irradiation does not affect seed germination. The experimental results reveal that oxygen related radicals strongly enhance growth, whereas ions and photons do not.

  11. Hard graphitelike hydrogenated amorphous carbon grown at high rates by a remote plasma

    SciTech Connect

    Singh, S. V.; Zaharia, T.; Creatore, M.; Sanden, M. C. M. van de; Groenen, R.; Van Hege, K.

    2010-01-15

    Hydrogenated amorphous carbon (a-C:H) deposited from an Ar-C{sub 2}H{sub 2} expanding thermal plasma chemical vapor deposition (ETP-CVD) is reported. The downstream plasma region of an ETP is characterized by a low electron temperature ({approx}0.3 eV), which leads to an ion driven chemistry and negligible physical effects, such as ion bombardment (ion energy <2 eV) on the depositing surface. The material properties in ETP-CVD can be controlled by varying the plasma chemistry. In this article we investigate the change in a-C:H material properties by varying the Ar/C{sub 2}H{sub 2} gas flow ratio over a wide range (1.33-150), with emphasis on low gas flow ratios (1.33-5). By changing the Ar/C{sub 2}H{sub 2} gas flow ratio, the gas residence time in the ETP expansion can be tuned, which in turn defines the chemistry of the ETP-CVD. Soft polymerlike a-C:H to moderately hard a-C:H films have been deposited by lowering the Ar/C{sub 2}H{sub 2} gas flow ratio. Recently, under very low Ar/C{sub 2}H{sub 2} gas flow ratios, a hard graphitelike a-C:H material has been deposited. The striking feature of this material is the infrared absorption spectrum in the C-H{sub x} stretching region (2800-3100 cm{sup -1}), which is a distinct narrow bimodal spectrum evolving from a broad spectrum for the moderately hard a-C:H. This transition was attributed to the absence of end groups (sp{sup 2} CH{sub 2} and sp{sup 3} CH{sub 3}), which favors an enhanced cross-linking in the film in a similar effect to elevated ion bombardment or annealing. Moreover, the hard graphitelike film has an increased refractive index (n) as high as 2.5 at 633 nm with a corresponding mass density of {approx}2.0 g/cm{sup 3}.

  12. The Role of Plasma in Plasma Enhanced Chemical Vapour Deposition of Nanostructure Growth

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Meyyappan, M.; Teo, Kenneth B. K.; Lacerda, Rodrigo G.; Rupesinghe, Nalin L.

    2004-01-01

    Chemical vapour deposition (CVD) has become the preferred process for high yield growth of carbon nanotubes and nanofibres because of its ability to pattern growth through lithographic positioning of transition metal catalysts on substrates. Many potential applications of nanotubes such as field emitters [1] require not only patterned growth but also vertical alignment. Some degree of ali,ment in thermal CVD processes can be obtained when carbon nanotubes are grown closely together as a result of van der Waals interactions. The ali,onment however is marginal, and the van der Waals prerequisite makes growth of freestanding nanofibres with thermal CVD unrealizable. The application of electric fields as a means of ali,onment has been shown to overcome this limitation [2-5], and highly aligned nanostructures can be grown if electric fields on the order of 0.5 V/microns are employed. Plasma enhanced CVD in various configurations including dc, rf, microwave, inductive and electron cyclotron resonance has been pursued as a means of enabling alignment in the CVD process. However, the sheath fields for the non-dc sources are in general not sufficient for a high degree of ali,pment and an additional dc bias is usually applied to the growth substrate. This begs the question as to the actual role of the plasma. It is clear that the plasma itself is not required for aligned growth as references [3] and [4] employed fields through small applied voltages (3-20 V) across very small electrode spacings (10-100 microns) and thus avoided striking a discharge.

  13. Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

    SciTech Connect

    Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

    2009-07-01

    Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 mus, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

  14. Comparative Study of Plasma Parameters in Magnetic Pole Enhanced Inductively Coupled Argon Plasmas

    NASA Astrophysics Data System (ADS)

    F., Jan; W. Khan, A.; Saeed, A.; Zakaullah, M.

    2013-04-01

    Langmuir probe measurements of radio frequency (RF) magnetic pole enhanced inductively coupled (MaPE-ICP) argon plasma were accomplished to obtain the electron number densities and electron temperatures. The measurements were carried out with a fixed RF frequency of 13.56 MHz in a pressure range of 7.5 mTorr to 75 mTorr at an applied RF power of 10 W and 100 W. These results are compared with a global (volume average) model. The results show good agreement between theoretical and experimental measurements. The electron number density shows an increasing trend with both RF power and pressure while the electron temperature shows decreasing trend as the pressure increases. The difference in the plasma potential and floating potential as a function of electron temperature measured from the electrical probe and that obtained theoretically shows a linear relation with a small difference in the coefficient of proportionality. The intensity of the emission line at 750.4 nm due to 2p1 → 1s2 (Paschen's notation) transition closely follows the variation of ne with RF power and filling gas pressure. Measured electron energy probability function (EEPF) shows that electron occupation changes mostly in the high-energy tail, which highlights close similarity of 750.4 nm argon line to ne.

  15. Hydrogen desorption from hydrogen fluoride and remote hydrogen plasma cleaned silicon carbide (0001) surfaces

    SciTech Connect

    King, Sean W. Tanaka, Satoru; Davis, Robert F.; Nemanich, Robert J.

    2015-09-15

    Due to the extreme chemical inertness of silicon carbide (SiC), in-situ thermal desorption is commonly utilized as a means to remove surface contamination prior to initiating critical semiconductor processing steps such as epitaxy, gate dielectric formation, and contact metallization. In-situ thermal desorption and silicon sublimation has also recently become a popular method for epitaxial growth of mono and few layer graphene. Accordingly, numerous thermal desorption experiments of various processed silicon carbide surfaces have been performed, but have ignored the presence of hydrogen, which is ubiquitous throughout semiconductor processing. In this regard, the authors have performed a combined temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) investigation of the desorption of molecular hydrogen (H{sub 2}) and various other oxygen, carbon, and fluorine related species from ex-situ aqueous hydrogen fluoride (HF) and in-situ remote hydrogen plasma cleaned 6H-SiC (0001) surfaces. Using XPS, the authors observed that temperatures on the order of 700–1000 °C are needed to fully desorb C-H, C-O and Si-O species from these surfaces. However, using TPD, the authors observed H{sub 2} desorption at both lower temperatures (200–550 °C) as well as higher temperatures (>700 °C). The low temperature H{sub 2} desorption was deconvoluted into multiple desorption states that, based on similarities to H{sub 2} desorption from Si (111), were attributed to silicon mono, di, and trihydride surface species as well as hydrogen trapped by subsurface defects, steps, or dopants. The higher temperature H{sub 2} desorption was similarly attributed to H{sub 2} evolved from surface O-H groups at ∼750 °C as well as the liberation of H{sub 2} during Si-O desorption at temperatures >800 °C. These results indicate that while ex-situ aqueous HF processed 6H-SiC (0001) surfaces annealed at <700 °C remain terminated by some surface C–O and

  16. Interactive Computer-Enhanced Remote Viewing System (ICERVS): Subsystem design report - Phase 2

    SciTech Connect

    Smith, D.A.

    1994-04-22

    This ICERVS Phase II Subsystem Design Report describes the detailed software design of the Phase II Interactive Computer-Enhanced Remote Viewing System (ICERVS). ICERVS is a computer-based system that provides data acquisition, data visualization, data analysis, and model synthesis to support robotic remediation of hazardous environments. Due to the risks associated with hazardous environments, remediation must be conducted remotely using robotic systems, which, in turn, must rely on 3D models of their workspace to support both task and path planning with collision avoidance. Tools such as ICERVS are vital to accomplish remediation tasks in a safe, efficient manner. The 3D models used by robotic systems are based on solid modeling methods, in which objects are represented by enclosing surfaces (polygons, quadric surfaces, patches, etc.) or collections of primitive solids (cubes, cylinders, etc.). In general, these 3D models must be created and/or verified by actual measurements made in the robotics workspace. However, measurement data is empirical in nature, with typical output being a collection of xyz triplets that represent sample points on some surface(s) in the workspace. As such, empirical data cannot be readily analyzed in terms of geometric representations used in robotic workspace models. The primary objective of ICERVS is to provide a reliable description of a workspace based on dimensional measurement data and to convert that description into 3D models that can be used by robotic systems. ICERVS will thus serve as a critical factor to allow robotic remediation tasks to be performed more effectively (faster, safer) and economically than with present systems.

  17. Remote plasma cleaning of optical surfaces: Cleaning rates of different carbon allotropes as a function of RF powers and distances

    NASA Astrophysics Data System (ADS)

    Cuxart, M. González; Reyes-Herrera, J.; Šics, I.; Goñi, A. R.; Fernandez, H. Moreno; Carlino, V.; Pellegrin, E.

    2016-01-01

    An extended study on an advanced method for the cleaning of carbon contaminations from large optical surfaces using a remote inductively coupled low-pressure RF plasma source (GV10x DownStream Asher) is reported. Technical and scientific features of this scaled up cleaning process are analysed, such as the cleaning efficiency for different carbon allotropes (amorphous and diamond-like carbon) as a function of feedstock gas, RF power (from 30 to 300 W), and source-object distances (415 to 840 mm). The underlying physical phenomena for these functional dependences are discussed.

  18. Characterization of plasma-enhanced atomic layer deposition of Al{sub 2}O{sub 3} using dimethylaluminum isopropoxide

    SciTech Connect

    Yang, Jialing; Eller, Brianna S.; Nemanich, Robert J.; Kaur, Manpuneet

    2014-03-15

    In this research, Al{sub 2}O{sub 3} films were grown by remote plasma-enhanced atomic layer deposition using a nonpyrophoric precursor, dimethylaluminum isopropoxide (DMAI), and oxygen plasma. After optimization, the growth rate was determined to be ∼1.5 Å/cycle within a growth window of 25–220 °C; the higher growth rate than reported for thermal atomic layer deposition was ascribed to the higher reactivity of the plasma species compared with H{sub 2}O and the adsorption of active oxygen at the surface, which was residual from the oxygen plasma exposure. Both effects enhance DMAI chemisorption and increase the saturation density. In addition, a longer oxygen plasma time was required at room temperature to complete the reaction and decrease the carbon contamination below the detection limit of x-ray photoemission spectroscopy. The properties of the subsequent Al{sub 2}O{sub 3} films were measured for different temperatures. When deposited at 25 °C and 200 °C, the Al{sub 2}O{sub 3} films demonstrated a single Al-O bonding state as measured by x-ray photoemission spectroscopy, a similar band gap of 6.8±0.2 eV as determined by energy loss spectroscopy, a similar index of refraction of 1.62±0.02 as determined by spectroscopic ellipsometry, and uniform growth with a similar surface roughness before and after growth as confirmed by atomic force microscopy. However, the room temperature deposited Al{sub 2}O{sub 3} films had a lower mass density (2.7 g/cm{sup 3} compared with 3.0 g/cm{sup 3}) and a higher atomic ratio of O to Al (2.1 compared with 1.6) as indicated by x-ray reflectivity and Rutherford backscattering spectroscopy, respectively.

  19. Plasma torch for ignition, flameholding and enhancement of combustion in high speed flows

    NASA Technical Reports Server (NTRS)

    O'Brien, Walter F. (Inventor); Billingsley, Matthew C. (Inventor); Sanders, Darius D. (Inventor); Schetz, Joseph A. (Inventor)

    2009-01-01

    Preheating of fuel and injection into a plasma torch plume fro adjacent the plasma torch plume provides for only ignition with reduced delay but improved fuel-air mixing and fuel atomization as well as combustion reaction enhancement. Heat exchange also reduced erosion of the anode of the plasma torch. Fuel mixing atomization, fuel mixture distribution enhancement and combustion reaction enhancement are improved by unsteady plasma torch energization, integral formation of the heat exchanger, fuel injection nozzle and plasma torch anode in a more compact, low-profile arrangement which is not intrusive on a highspeed air flow with which the invention is particularly effective and further enhanced by use of nitrogen as a feedstock material and inclusion of high pressure gases in the fuel to cause effervescence during injection.

  20. PIII Plasma Density Enhancement by a New DC Power Source

    SciTech Connect

    Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Granda-Gutierrez, E. E.; Piedad-Beneitez, A. de la; Munoz-Castro, A. E.; Valencia A, R.; Barocio, S. R.; Mercado-Cabrera, A.; Pena-Eguiluz, R.

    2006-12-04

    In practical terms, those plasmas produced by a DC voltage power supply do not attain densities above the 108 to 109 cm-3 band. Here we present a power supply, controlled in current and voltage, which has been successfully designed and constructed delivering plasma densities in the orders of 109 - 1010 cm-3. Its experimental performance test was conducted within one toroidal and one cylindrical chambers capable of 29 and 35 litres, respectively, using nitrogen gas. The DC plasma was characterized by a double electric probe. Several physical phenomena present in the PIII process have been keenly investigated including plasma sheath dynamics, interaction of plasma and surface, etc. In this paper we analyze the effect of the implantation voltage, plasma density and pulse time in the PIII average heating power and fluence density.

  1. Plasma enhanced C1 chemistry for green technology

    NASA Astrophysics Data System (ADS)

    Nozaki, Tomohiro

    2013-09-01

    Plasma catalysis is one of the innovative next generation green technologies that meet the needs for energy and materials conservation as well as environmental protection. Non-thermal plasma uniquely generates reactive species independently of reaction temperature, and these species are used to initiate chemical reactions at unexpectedly lower temperatures than normal thermochemical reactions. Non-thermal plasma thus broadens the operation window of existing chemical conversion processes, and ultimately allows modification of the process parameters to minimize energy and material consumption. We have been specifically focusing on dielectric barrier discharge (DBD) as one of the viable non-thermal plasma sources for practical fuel reforming. In the presentation, room temperature one-step conversion of methane to methanol and hydrogen using a miniaturized DBD reactor (microplasma reactor) is highlighted. The practical impact of plasma technology on existing C1-chemistry is introduced, and then unique characteristics of plasma fuel reforming such as non-equilibrium product distribution is discussed.

  2. Field-enhanced electrodes for additive-injection non-thermal plasma (NTP) processor

    DOEpatents

    Rosocha, Louis A.; Ferreri, Vincent; Kim, Yongho

    2009-04-21

    The present invention comprises a field enhanced electrode package for use in a non-thermal plasma processor. The field enhanced electrode package includes a high voltage electrode and a field-enhancing electrode with a dielectric material layer disposed in-between the high voltage electrode and the field-enhancing electrode. The field-enhancing electrode features at least one raised section that includes at least one injection hole that allows plasma discharge streamers to occur primarily within an injected additive gas.

  3. Effects of plasma power on the growth of carbon nanotubes in the plasma enhanced chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Abdi, Y.; Arzi, E.; Mohajerzadeh, S.

    2008-11-01

    Effects of plasma power on the growth of the multi-wall carbon nanotubes (CNTs) are reported. CNTs were grown on the silicon wafers by plasma enhanced chemical vapor deposition (PECVD) method using a mixture of acetylene and hydrogen at the temperature of 650°C. Plasma powers ranging from zero to 35W were applied on the samples and the effects of different magnitudes of the plasma power on the growth direction of the CNTs were investigated. Regular vertically aligned nanotubes were obtained at plasma power of 25W. In order to set on the plasma during the growth, electrical force was applied on the carbon ions. Nickel layer was used as a catalyst, and prior to the nanotubes growth step, it was treated by hydrogen plasma bombardment in order to obtain the Ni nano-islands. In this step, as the plasma power on the Ni layer was increased, the grain size of nickel nano-particles decreased, and hence, nanotubes of smaller diameter were obtained later on. At the last step some anomalous structures of agglomerated CNTs were obtained by controlling the plasma power. Samples were analyzed by scanning tunneling microscopy (STM) and scanning electron microscopy (SEM).

  4. Enhanced stability of Cu-BTC MOF via perfluorohexane plasma-enhanced chemical vapor deposition.

    PubMed

    Decoste, Jared B; Peterson, Gregory W; Smith, Martin W; Stone, Corinne A; Willis, Colin R

    2012-01-25

    Metal organic frameworks (MOFs) are a leading class of porous materials for a wide variety of applications, but many of them have been shown to be unstable toward water. Cu-BTC (1,3,5 benzenetricarboxylic acid, BTC) was treated with a plasma-enhanced chemical vapor deposition (PECVD) of perfluorohexane creating a hydrophobic form of Cu-BTC. It was found that the treated Cu-BTC could withstand high humidity and even submersion in water much better than unperturbed Cu-BTC. Through Monte Carlo simulations it was found that perfluorohexane sites itself in such a way within Cu-BTC as to prevent the formation of water clusters, hence preventing the decomposition of Cu-BTC by water. This PECVD of perfluorohexane could be exploited to widen the scope of practical applications of Cu-BTC and other MOFs. PMID:22239201

  5. Enhanced focusing of laser beams in semiconductor plasmas

    NASA Astrophysics Data System (ADS)

    Gupta, D. N.; Suk, H.

    2007-02-01

    The beating of two copropagating laser beams (having frequency difference Δω ≈ωp, where ωp is the plasma frequency) can resonantly excite a large amplitude plasma wave in a narrow-gap semiconductor [V. I. Berezhiani and S. M. Mahajan, Phys. Rev. B 55, 9247 (1997)]. The higher ponderomotive force on the electrons due to the plasma beat wave makes the medium highly nonlinear. As a result, the incident laser beams become self-focused due to the nonlinearity by the ponderomotive force. In this paper, we show the self-focusing and spot size evolution of the laser beams in semiconductor plasmas.

  6. Enhancement of electrical properties of polyimide films by plasma treatment

    NASA Astrophysics Data System (ADS)

    Meddeb, A. Barhoumi; Ounaies, Z.; Lanagan, M.

    2016-04-01

    In this study, the effect of oxygen plasma treatment on the electrical and surface properties of polyimide, Kapton HN, film is investigated. The plasma treatment led to an increase in the oxygen presence on the polyimide surface and a marked surface hydrophilicity. The plasma treatment led to an increase in the dielectric breakdown and Weibull modulus as well as a remarkable reduction in the scatter of all electrical measurements. There is a significant reduction in the high field/high temperature leakage current after plasma treatment. These findings have important implications in the development and improvement of dielectric polymer capacitors.

  7. Integrated computer-enhanced remote viewing system. Quarterly report Number 5, October 1993--December 1993

    SciTech Connect

    1994-02-22

    The Interactive, Computer-Enhanced, Remote Viewing System (ICERVS) is a system designed to provide a reliable geometric description of a robotic task space in a fashion that enables robotic remediation to be carried out more efficiently and economically that with present systems. The key elements are a faithful way to store empirical data and a friendly user interface that provides an operator with timely access to all that is known about a scene. ICERVS will help an operator to analyze a scene and generate additional geometric data for automating significant portions of the remediation activity. Features that enable this include the following: storage and display of empirical sensor data; ability to update segments of the geometric description of the task space; side-by-side comparisons of a live TV scene and a computer generated view of the same scene; ability to create and display computer models of perceived objects in the task space, together with textual comments, and easy export of data to robotic world models for robot guidance.

  8. Enhancing computer literacy and information retrieval skills: A rural and remote nursing and midwifery workforce study.

    PubMed

    Mills, Jane; Francis, Karen; McLeod, Margaret; Al-Motlaq, Mohammad

    2015-01-01

    Nurses and midwives collectively, represent the largest workforce category in rural and remote areas of Australia. Maintaining currency of practice and attaining annual licensure with the Australian Health Practitioners Regulatory Authority (AHPRA) present challenges for individual nurses and midwives and for their health service managers. Engagement with information and communication technologies, in order for geographically isolated clinicians to access ongoing education and training, is considered a useful strategy to address such challenges. This paper presents a pre- and post-test study design. It examines the impact of an online continuing professional development (CPD) program on Australian rural nurses and midwives. The aims of the program were to increase basic skill acquisition in the utilisation of common computer software, the use of the Internet and the enhancement of email communication. Findings from the study demonstrate that participants who complete a relevant CPD program gain confidence in the use of information and communication technologies. Further, increased confidence leads to increased access to contemporary, reliable and important health care information on the Internet, in addition to clinicians adopting email as a regular method of communication. Health care employers commonly assume employees are skilled users of information and communication technologies. However, findings from this study contradict such assumptions. It is argued in the recommendations that health care employees should be given regular access to CPD programs designed to introduce them to information and communication technologies. Developing knowledge and skills in this area has the potential to improve staff productivity, raise health care standards and improve patient outcomes. PMID:26552199

  9. Integrated Computer-Enhanced Remote Viewing System. Quarterly report number 4, July--October 1993

    SciTech Connect

    Not Available

    1993-11-30

    The Interactive, Computer-Enhanced, Remote Viewing System (ICERVS) is a system designed to provide a reliable geometric description of a robotic task space in a fashion that enables robotic remediation to be carried out more efficiently and economically than with present systems. The key elements are a faithful way to store empirical data and a friendly user interface that provides an operator with timely access to all that is known about a scene. The development of ICERVS is to occur in three phases. Phase 1 will focus on the development of the Data Library, which contains the geometric data about the task space and the objects in it, and the Toolkit, which includes the mechanisms for manipulating and displaying both empirical and model data. Phase 2 will concentrate on integrating these subsystems with a sensor subsystem into one working system. Some additional functionality will be incorporated in the Data Library and Toolkit subsystems. Phase 3 will expand the configuration to meet the needs of a full scale demonstration of the interactive mapping of some waste site to be identified. The second Phase of the ICERVS project consists of nine tasks. Significant efforts were devoted to the completion of Task 1: Intermediate System Design, and Task 3: Computer Upgrade. This report describes progress in these two tasks.

  10. Fabrication of Carbon Nanotubes by Slot-Excited Microwave Plasma-Enhanced Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Shim, Gyu Il; Kojima, Yoshihiro; Kono, Satoshi; Ohno, Yutaka; Ishijima, Tatsuo

    2008-07-01

    Carbon nanotubes (CNTs) are fabricated by adopting plasma-enhanced chemical vapor deposition (PECVD) with a planar microwave plasma source. Plasma is produced by a slot antenna at 2.45-GHz microwave injection in CH4/H2 mixture. In this study, it is shown that avoiding the exposure of the substrate to the plasma drastically improves the CNT growth. Furthermore, it is found that the CNT quality can be controlled with the optimization of one of the steps in the catalyst treatment, such as the preheating procedure; the treated catalyst is considered to be unaffected by the heating in the high-density microwave plasma treatment during the CNT growth.

  11. Strongly Enhanced Stimulated Brillouin Backscattering in an Electron-Positron Plasma

    NASA Astrophysics Data System (ADS)

    Edwards, Matthew R.; Fisch, Nathaniel J.; Mikhailova, Julia M.

    2016-01-01

    Stimulated Brillouin backscattering of light is shown to be drastically enhanced in electron-positron plasmas, in contrast to the suppression of stimulated Raman scattering. A generalized theory of three-wave coupling between electromagnetic and plasma waves in two-species plasmas with arbitrary mass ratios, confirmed with a comprehensive set of particle-in-cell simulations, reveals violations of commonly held assumptions about the behavior of electron-positron plasmas. Specifically, in the electron-positron limit three-wave parametric interaction between light and the plasma acoustic wave can occur, and the acoustic wave phase velocity differs from its usually assumed value.

  12. Plasma enhanced vortex fluidic device manipulation of graphene oxide.

    PubMed

    Jones, Darryl B; Chen, Xianjue; Sibley, Alexander; Quinton, Jamie S; Shearer, Cameron J; Gibson, Christopher T; Raston, Colin L

    2016-08-25

    A vortex fluid device (VFD) with non-thermal plasma liquid processing within dynamic thin films has been developed. This plasma-liquid microfluidic platform facilitates chemical processing which is demonstrated through the manipulation of the morphology and chemical character of colloidal graphene oxide in water. PMID:27506139

  13. Microwave plasma enhanced chemical vapor deposition of nanocrystalline diamond films by bias-enhanced nucleation and bias-enhanced growth

    SciTech Connect

    Chu, Yueh-Chieh; Tzeng, Yonhua; Auciello, Orlando

    2014-01-14

    Effects of biasing voltage-current relationship on microwave plasma enhanced chemical vapor deposition of ultrananocrystalline diamond (UNCD) films on (100) silicon in hydrogen diluted methane by bias-enhanced nucleation and bias-enhanced growth processes are reported. Three biasing methods are applied to study their effects on nucleation, growth, and microstructures of deposited UNCD films. Method A employs 320 mA constant biasing current and a negative biasing voltage decreasing from −490 V to −375 V for silicon substrates pre-heated to 800 °C. Method B employs 400 mA constant biasing current and a decreasing negative biasing voltage from −375 V to −390 V for silicon pre-heated to 900 °C. Method C employs −350 V constant biasing voltage and an increasing biasing current up to 400 mA for silicon pre-heated to 800 °C. UNCD nanopillars, merged clusters, and dense films with smooth surface morphology are deposited by the biasing methods A, B, and C, respectively. Effects of ion energy and flux controlled by the biasing voltage and current, respectively, on nucleation, growth, microstructures, surface morphologies, and UNCD contents are confirmed by scanning electron microscopy, high-resolution transmission-electron-microscopy, and UV Raman scattering.

  14. Electrically enhanced MBR system for total nutrient removal in remote northern applications.

    PubMed

    Wei, V; Elektorowicz, M; Oleszkiewicz, J A

    2012-01-01

    Thousands of sparsely populated communities scatter in the remote areas of northern Canada. It is economically preferable to adopt the decentralized systems to treat the domestic wastewater because of the vast human inhabitant distribution and cold climatic conditions. Electro-technologies such as electrofiltration, elctrofloatation, electrocoagulation and electrokinetic separation have been applied in water and conventional wastewater treatment for decades due to the minimum requirements of chemicals as well as ease of operation. The membrane bioreactor (MBR) is gaining popularity in recent years as an alternative water/wastewater treatment technology. However, few studies have been conducted to hyphenate these two technologies. The purpose of this work is to design a novel electrically enhanced membrane bioreactor (EMBR) as an alternative decentralized wastewater treatment system with improved nutrient removal and reduced membrane fouling. Two identical submerged membranes (GE ZW-1 hollow fiber module) were used for the experiment, with one as a control. The EMBR and control MBR were operated for 4 months at room temperature (20 ± 2 °C) with synthetic feed and 2 months at 10 °C with real sewage. The following results were observed: (1) the transmembrane pressure (TMP) increased significantly more slowly in the EMBR and the interval between the cleaning cycles of the EMBR increased at least twice; (2) the dissolved chemical oxygen demand (COD) or total organic carbon (TOC) in the EMBR biomass was reduced from 30 to 51%, correspondingly, concentrations of the extracellular polymeric substances (EPS), the major suspicious membrane foulants, decreased by 26-46% in the EMBR; (3) both control and EMBR removed >99% of ammonium-N and >95% of dissolved COD, in addition, ortho-P removal in the EMBR was >90%, compared with 47-61% of ortho-P removal in the MBR; and (4) the advantage of the EMBR over the conventional MBR in terms of membrane fouling retardation and

  15. Interactive Online Tools for Enhancing Student Learning Experiences in Remote Sensing

    ERIC Educational Resources Information Center

    Joyce, Karen E.; Boitshwarelo, Bopelo; Phinn, Stuart R.; Hill, Greg J. E.; Kelly, Gail D.

    2014-01-01

    The rapid growth in Information and Communications Technologies usage in higher education has provided immense opportunities to foster effective student learning experiences in geography. In particular, remote sensing lends itself to the creative utilization of multimedia technologies. This paper presents a case study of a remote sensing computer…

  16. Skeletal cell differentiation is enhanced by atmospheric dielectric barrier discharge plasma treatment.

    PubMed

    Steinbeck, Marla J; Chernets, Natalie; Zhang, Jun; Kurpad, Deepa S; Fridman, Gregory; Fridman, Alexander; Freeman, Theresa A

    2013-01-01

    Enhancing chondrogenic and osteogenic differentiation is of paramount importance in providing effective regenerative therapies and improving the rate of fracture healing. This study investigated the potential of non-thermal atmospheric dielectric barrier discharge plasma (NT-plasma) to enhance chondrocyte and osteoblast proliferation and differentiation. Although the exact mechanism by which NT-plasma interacts with cells is undefined, it is known that during treatment the atmosphere is ionized generating extracellular reactive oxygen and nitrogen species (ROS and RNS) and an electric field. Appropriate NT-plasma conditions were determined using lactate-dehydrogenase release, flow cytometric live/dead assay, flow cytometric cell cycle analysis, and Western blots to evaluate DNA damage and mitochondrial integrity. We observed that specific NT-plasma conditions were required to prevent cell death, and that loss of pre-osteoblastic cell viability was dependent on intracellular ROS and RNS production. To further investigate the involvement of intracellular ROS, fluorescent intracellular dyes Mitosox (superoxide) and dihydrorhodamine (peroxide) were used to assess onset and duration after NT-plasma treatment. Both intracellular superoxide and peroxide were found to increase immediately post NT-plasma treatment. These increases were sustained for one hour but returned to control levels by 24 hr. Using the same treatment conditions, osteogenic differentiation by NT-plasma was assessed and compared to peroxide or osteogenic media containing β-glycerolphosphate. Although both NT-plasma and peroxide induced differentiation-specific gene expression, neither was as effective as the osteogenic media. However, treatment of cells with NT-plasma after 24 hr in osteogenic or chondrogenic media significantly enhanced differentiation as compared to differentiation media alone. The results of this study show that NT-plasma can selectively initiate and amplify ROS signaling to enhance

  17. Skeletal Cell Differentiation Is Enhanced by Atmospheric Dielectric Barrier Discharge Plasma Treatment

    PubMed Central

    Zhang, Jun; Kurpad, Deepa S.; Fridman, Gregory; Fridman, Alexander; Freeman, Theresa A.

    2013-01-01

    Enhancing chondrogenic and osteogenic differentiation is of paramount importance in providing effective regenerative therapies and improving the rate of fracture healing. This study investigated the potential of non-thermal atmospheric dielectric barrier discharge plasma (NT-plasma) to enhance chondrocyte and osteoblast proliferation and differentiation. Although the exact mechanism by which NT-plasma interacts with cells is undefined, it is known that during treatment the atmosphere is ionized generating extracellular reactive oxygen and nitrogen species (ROS and RNS) and an electric field. Appropriate NT-plasma conditions were determined using lactate-dehydrogenase release, flow cytometric live/dead assay, flow cytometric cell cycle analysis, and Western blots to evaluate DNA damage and mitochondrial integrity. We observed that specific NT-plasma conditions were required to prevent cell death, and that loss of pre-osteoblastic cell viability was dependent on intracellular ROS and RNS production. To further investigate the involvement of intracellular ROS, fluorescent intracellular dyes Mitosox (superoxide) and dihydrorhodamine (peroxide) were used to assess onset and duration after NT-plasma treatment. Both intracellular superoxide and peroxide were found to increase immediately post NT-plasma treatment. These increases were sustained for one hour but returned to control levels by 24 hr. Using the same treatment conditions, osteogenic differentiation by NT-plasma was assessed and compared to peroxide or osteogenic media containing β-glycerolphosphate. Although both NT-plasma and peroxide induced differentiation-specific gene expression, neither was as effective as the osteogenic media. However, treatment of cells with NT-plasma after 24 hr in osteogenic or chondrogenic media significantly enhanced differentiation as compared to differentiation media alone. The results of this study show that NT-plasma can selectively initiate and amplify ROS signaling to enhance

  18. Application of a non-thermal plasma to combustion enhancement.

    SciTech Connect

    Rosocha, L. A.; Kim, Y.; Stange, Sabine

    2004-01-01

    As a primary objective, researchers in Los Alamos National Laboratory's P-24 Plasma Physics group are aiming to minimize U.S. energy dependency on foreign resources through experiments incorporating a plasma assisted combustion unit. Under this broad category, researchers seek to increase efficiency and reduce NO{sub x}/SO{sub x} and unburned hydrocarbon emissions in IC-engines, gas-turbine engines, and burner units. To date, the existing lean burn operations, consisting of higher air to fuel ratio, have successfully operated in a regime where reduced NO{sub x}/SO{sub x} emissions are expected and have also shown increased combustion efficiency (less unburned hydrocarbon) for propane. By incorporating a lean burn operation assisted by a non-thermal plasma (NTP) reactor, the fracturing of hydrocarbons can occur with increased power (combustion, efficiency, and stability). Non-thermal plasma units produce energetic electrons, but avoid the high gas and ion temperatures involved in thermal plasmas. One non-thermal plasma method, known as silent discharge, allows free radicals to act in propagating combustion reactions, as well as intermediaries in hydrocarbon fracturing. Using non-thermal plasma units, researchers have developed a fuel activation/conversion system capable of decreasing pollutants while increasing fuel efficiency, providing a path toward future U.S. energy independence.

  19. ICRF-enhanced plasma potentials in the SOL of Alcator C-Mod

    SciTech Connect

    Ochoukov, R.; Whyte, D. G.; Brunner, D.; LaBombard, B.; Lipschultz, B.; Terry, J. L.; Wukitch, S. J.; D'Ippolito, D. A.; Myra, J. R.

    2014-02-12

    We performed an extensive survey of the plasma potential in the scrape-off layer (SOL) of Ion Cyclotron Range-of Frequencies (ICRF)-heated discharges on Alcator C-Mod. Our results show that plasma potentials are enhanced in the presence of ICRF power and plasma potential values of >100 V are often observed. Such potentials are high enough to induce sputtering of high-Z molybdenum (Mo) plasma facing components by deuterium ions on C-Mod. For comparison, the plasma potential in Ohmic discharges is typically less than 10 V, well below the threshold needed to induce Mo sputtering by deuterium ions. ICRF-enhanced plasma potentials are observed in the SOL regions that both magnetically map and do not map to active ICRF antennas. Regions that magnetically map to active ICRF antennas are accessible to slow waves directly launched by the antennas and these regions experience plasma potential enhancement that is partially consistent with the slow wave rectification mechanism. One of the most defining features of the slow wave rectification is a threshold appearance of significant plasma potentials (>100 V) when the dimensionless rectification parameter Λ{sub −o} is above unity and this trend is observed experimentally. We also observe ICRF-enhanced plasma potentials >100 V in regions that do not magnetically map to the active antennas and, hence, are not accessible for slow waves launched directly by the active antennas. However, unabsorbed fast waves can reach these regions. The general trend that we observe in these 'un-mapped' regions is that the plasma potential scales with the strength of the local RF wave fields with the fast wave polarization and the highest plasma potentials are observed in discharges with the highest levels of unabsorbed ICRF power. Similarly, we find that core Mo levels scale with the level of unabsorbed ICRF power suggesting a link between plasma potentials in the SOL and the strength of the impurity source.

  20. Remote sensing of auroral E region plasma structures by radio, radar, and UV techniques at solar minimum

    SciTech Connect

    Basu, S.; Valladares, C.E. ); Basu, S.; Eastes, R.; Huffman, R.E. ); Daniell, R.E. ); Chaturvedi, P.K. ); Livingston, R.C. )

    1993-02-01

    The unique capability of the Polar BEAR satellite to simultaneously image auroral luminosities at multiple ultraviolet (UV) wavelengths and to remote sense large-scale (hundreds to tens of kilometers) and small-scale (kilometers to hundreds of meters) plasma density structures with its multifrequency beacon package is utilized to probe the auroral E region in the vicinity of the incoherent scatter radar (ISR) facility near Sondrestrom. In particular, we present coordinated observations on two nights obtained during the sunspot minimum (sunspot number < 10) January-February 1987 period when good spatial and temporal conjunction was obtained between Polar BEAR overflights and Sondrestrom ISR measurements. With careful coordinated observations we were able to confirm that the energetic particle precipitation responsible for the UV emissions causes the electron density increases in the E region. The integrations up to the topside of these ISR electron density profiles were consistent with the total electron content (TEC) measured by the Polar BEAR satellite. An electron transport model was utilized to determine quantitatively the electron density profiles which could be produced by the particle precipitation, which also produced multiple UV emissions measured by the imager; these profiles were found to be in good agreement with the observed ISR profiles in the E region. This outer scale size is also consistent with the measured phase to amplitude scintillation ratio. An estimate of the linear growth rate of the gradient-drift instability in the E region shows that these plasma density irregularities could have been generated by this process. The mutual consistency of these different sets of measurements provides confidence in the ability of the different techniques to remote sense large- and small-scale plasma density structures in the E region at least during sunspot minimum when the convection-dominated high-latitude F region is fairly weak. 56 refs., 16 figs.

  1. Plasma-enhanced atomic layer deposition: a gas-phase route to hydrophilic, glueable polytetrafluoroethylene.

    PubMed

    Roy, Amit K; Dendooven, Jolien; Deduytsche, Davy; Devloo-Casier, Kilian; Ragaert, Kim; Cardon, Ludwig; Detavernier, Christophe

    2015-02-28

    This communication reports an approach based on plasma-enhanced atomic layer deposition of aluminium oxide for the functionalization of polytetrafluoroethylene (PTFE or "Teflon") surfaces. Alternating exposure of PTFE to oxygen plasma and trimethylaluminium causes a permanent hydrophilic effect, and a more than 10-fold improvement of the "glueability" of PTFE to aluminium. PMID:25631168

  2. Elastic waves and plasma - a new era of enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    Pashchenko, A. F.; Ageev, P. G.

    2016-06-01

    New technology of enhanced oil recovery - plasma pulse treatment is described. The basic problems of residual oil recovery observed, taking in consideration elastic properties of a reservoir and dominant frequencies of a stratum. Numerical estimates of major parameters of an impact to the reservoir while plasma pulse treatment obtained. Positive results of PPT application introduced.

  3. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    NASA Astrophysics Data System (ADS)

    Provine, J.; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin; Kim, Ki-Hyun; Prinz, Fritz B.

    2016-06-01

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiNx), particularly for use a low k dielectric spacer. One of the key material properties needed for SiNx films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiNx and evaluate the film's WER in 100:1 dilutions of HF in H2O. The remote plasma capability available in PEALD, enabled controlling the density of the SiNx film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiNx of 6.1 Å/min, which is similar to WER of SiNx from LPCVD reactions at 850 °C.

  4. The role of microwaves in the enhancement of laser-induced plasma emission

    NASA Astrophysics Data System (ADS)

    Khumaeni, Ali; Akaoka, Katsuaki; Miyabe, Masabumi; Wakaida, Ikuo

    2016-08-01

    We studied experimentally the effect of microwaves (MWs) on the enhancement of plasma emission achieved by laser-induced breakdown spectroscopy (LIBS). A laser plasma was generated on a calcium oxide pellet by a Nd:YAG laser (5 mJ, 532 nm, 8 ns) in reduced-pressure argon surrounding gas. A MW radiation (400 W) was injected into the laser plasma via a loop antenna placed immediately above the laser plasma to enhance the plasma emission. The results confirmed that when the electromagnetic field was introduced into the laser plasma region by the MWs, the lifetime of the plasma was extended from 50 to 500 µs, similar to the MW duration. Furthermore, the plasma temperature and electron density increased to approximately 10900 K and 1.5×1018 cm-3, respectively and the size of the plasma emission was extended to 15 mm in diameter. As a result, the emission intensity of Ca lines obtained using LIBS with MWs was enhanced by approximately 200 times compared to the case of LIBS without MWs.

  5. Enhanced betatron X-rays from axially modulated plasma wakefields

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Kaganovich, D.; Gordon, D.

    2015-06-01

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons trailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  6. Enhanced betatron X-rays from axially modulated plasma wakefields

    SciTech Connect

    Palastro, J. P.; Kaganovich, D.; Gordon, D.

    2015-06-15

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons trailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  7. Remote Handling and Plasma Conditions to Enable Fusion Nuclear Science R&D Using a US Component Testing Facility

    SciTech Connect

    Peng, Yueng Kay Martin; Burgess, Thomas W; Carroll, Adam J; Neumeyer, C. L.; Canik, John; Cole, Michael J; Dorland, W. D.; Fogarty, P. J.; Grisham, L.; Hillis, Donald Lee; Katoh, Yutai; Korsah, Kofi; Kotschenreuther, M.; LaHaye, R.; Mahajan, S.; Majeski, R.; Nelson, Brad E; Patton, Bradley D; Rasmussen, David A; Sabbagh, S. A.; Sontag, Aaron C; Stoller, Roger E; Tsai, C. C.; Vanlanju, P.; Wagner, Jill C; Yoder, III, Graydon L

    2009-08-01

    The use of a fusion component testing facility to study and establish, during the ITER era, the remaining scientific and technical knowledge needed by fusion Demo is considered and described in this paper. This use aims to lest components in an integrated fusion nuclear environment, for the first time, to discover and understand the underpinning physical properties, and to develop improved components for further testing, in a time-efficient manner. It requires a design with extensive modularization and remote handling of activated components, and flexible hot-cell laboratories. It further requires reliable plasma conditions to avoid disruptions and minimize their impact, and designs to reduce the divertor heat flux to the level of ITER design. As the plasma duration is extended through the planned ITER level (similar to 10(3) s) and beyond, physical properties with increasing time constants, progressively for similar to 10(4) s, similar to 10(5) s, and similar to 10(6) s, would become accessible for testing and R&D. The longest time constants of these are likely to be of the order of a week ( 106 S). Progressive stages of research operation are envisioned in deuterium, deuterium-tritium for the ITER duration, and deuterium-tritium with increasingly longer plasma durations. The fusion neutron fluence and operational duty factor anticipated for this "scientific exploration" phase of a component test facility are estimated to be up to 1 MW-yr/m(2) and up to 10%, respectively.

  8. Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

    DOEpatents

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2002-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.

  9. Diagnostic for Plasma Enhanced Chemical Vapor Deposition and Etch Systems

    NASA Technical Reports Server (NTRS)

    Cappelli, Mark A.

    1999-01-01

    In order to meet NASA's requirements for the rapid development and validation of future generation electronic devices as well as associated materials and processes, enabling technologies ion the processing of semiconductor materials arising from understanding etch chemistries are being developed through a research collaboration between Stanford University and NASA-Ames Research Center, Although a great deal of laboratory-scale research has been performed on many of materials processing plasmas, little is known about the gas-phase and surface chemical reactions that are critical in many etch and deposition processes, and how these reactions are influenced by the variation in operating conditions. In addition, many plasma-based processes suffer from stability and reliability problems leading to a compromise in performance and a potentially increased cost for the semiconductor manufacturing industry. Such a lack of understanding has hindered the development of process models that can aid in the scaling and improvement of plasma etch and deposition systems. The research described involves the study of plasmas used in semiconductor processes. An inductively coupled plasma (ICP) source in place of the standard upper electrode assembly of the Gaseous Electronics Conference (GEC) radio-frequency (RF) Reference Cell is used to investigate the discharge characteristics and chemistries. This ICP source generates plasmas with higher electron densities (approximately 10(exp 12)/cu cm) and lower operating pressures (approximately 7 mTorr) than obtainable with the original parallel-plate version of the GEC Cell. This expanded operating regime is more relevant to new generations of industrial plasma systems being used by the microelectronics industry. The motivation for this study is to develop an understanding of the physical phenomena involved in plasma processing and to measure much needed fundamental parameters, such as gas-phase and surface reaction rates. species

  10. ICRF Heating and Beta Enhancement of HBT-EP Plasmas

    NASA Astrophysics Data System (ADS)

    James, R.; Cates, C.; Klein, A.; Liu, Y.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.; Shilov, M.; Stillits, N.

    2004-11-01

    We describe experiments using the HBT-EP dual strap, inside launch ICRF heating system. RF heating is applied at 4.5MHz to deuterium discharges with 20 percent hydrogen minority species in order to heat electrons in the strongly damped mode-conversion regime. Experiments to date have shown antenna loading with plasmas pre-programmed to be strongly limited on the high field side (HFS) limiter. A HFS triple probe measures electron temperature and density near the antenna, and an RF pickup coil is employed to measure the fluctuating wave magnetic field. Experiments to date indicate that increased plasma density near the antenna improves coupling significantly. We will report on our progress in improving antenna-plasma coupling using the radial position feedback control system (RPFCS) in conjunction with the bias probe to achieve high plasma density near the antenna. Any bias probe induced H-modes may also help increase antenna coupling by increasing the plasma density near the edge. Progress on analysis and diagnosis of the antenna-oscillator circuit and loading measurements and current status of measurable RF heating will be presented.[1] [1] Collaboration with J. Hosea, R. Wilson, R. Budny, S. Paul et al., PPPL

  11. Enhanced acceleration of injected electrons in a laser-beat-wave-induced plasma channel.

    PubMed

    Tochitsky, S Ya; Narang, R; Filip, C V; Musumeci, P; Clayton, C E; Yoder, R B; Marsh, K A; Rosenzweig, J B; Pellegrini, C; Joshi, C

    2004-03-01

    Enhanced energy gain of externally injected electrons by a approximately 3 cm long, high-gradient relativistic plasma wave (RPW) is demonstrated. Using a CO2 laser beat wave of duration longer than the ion motion time across the laser spot size, a laser self-guiding process is initiated in a plasma channel. Guiding compensates for ionization-induced defocusing (IID) creating a longer plasma, which extends the interaction length between electrons and the RPW. In contrast to a maximum energy gain of 10 MeV when IID is dominant, the electrons gain up to 38 MeV energy in a laser-beat-wave-induced plasma channel. PMID:15089478

  12. Enhancement of Capabilities in Hyperspectral and Radar Remote Sensing for Environmental Assessment and Monitoring

    NASA Technical Reports Server (NTRS)

    Hepner, George F.

    1999-01-01

    The University of Utah, Department of Geography has developed a research and instructional program in satellite remote sensing and image processing. The University requested funds for the purchase of software licenses, mass storage for massive hyperspectral imager data sets, upgrades for the central data server to handle the additional storage capacity, a spectroradiometer for field data collection. These purchases have been made. This equipment will support research in one of the newest and most rapidly expanding areas of remote sensing.

  13. Nuclear Fusion Within Extremely Dense Plasma Enhanced by Quantum Particle Waves

    NASA Astrophysics Data System (ADS)

    Miao, Feng; Zheng, Xianjun; Deng, Baiquan

    2015-05-01

    Quantum effects play an enhancement role in p-p chain reactions occurring within stars. Such an enhancement is quantified by a wave penetration factor that is proportional to the density of the participating fuel particles. This leads to an innovative theory for dense plasma, and its result shows good agreement with independent data derived from the solar energy output. An analysis of the first Z-pinch machine in mankind's history exhibiting neutron emission leads to a derived deuterium plasma beam density greater than that of water, with plasma velocities exceeding 10000 km/s. Fusion power could be achieved by the intersection of four such pinched plasma beams with powerful head-on collisions in their common focal region due to the beam and target enhanced reaction. supported by the Fund for the Construction of Graduate Degree of China (No. 2014XWD-S0805)

  14. A physical model of radiated enhancement of plasma-surrounded antenna

    SciTech Connect

    Gao, Xiaotian; Wang, Chunsheng Jiang, Binhao; Zhang, Zhonglin

    2014-09-15

    A phenomenon that the radiated power may be enhanced when an antenna is surrounded by a finite plasma shell has been found in numerical and experimental studies. In this paper, a physical model was built to express the mechanism of the radiated enhancement. In this model, the plasma shell is treated as a parallel connection of a capacitance and a conductance whose parameters change with the system parameters (plasma density, collision frequency, and antenna frequency). So, the radiated enhancement can be explained by the resonance between the plasma shell and the infinite free space. Furthermore, the effects of system parameters on the radiated power are given and effects corresponding to mechanisms are performed based on the physical model.

  15. Enhancement of gas response of ZnO micro-nano structured films through plasma treatment

    NASA Astrophysics Data System (ADS)

    Delaunay, Jean-Jacques; Yanagisawa, Kazumasa; Nishino, Toshiki; Yamada, Ichiro

    2007-02-01

    Films of ZnO micro-nano structures were deposited on quartz substrates and subsequently plasma treated in O II, N II and CF 4. It was found that exposure to oxygen plasma enhanced gas response to ethanol vapor of the ZnO films by a factor 2. The effect of surface plasma treatments on the gas response of the ZnO films was discussed in reference to surface morphology observed by high-magnification SEM and surface chemical state determined by XPS. SEM observation revealed that O II plasma treatment induced less surface roughening than N II and CF 4 plasmas, in agreement with the view that O II plasma should reduce preferential sputtering. Deconvolution of the O 1s X-ray photoelectron peak indicated an increase in the Zn-O bond surface density relatively to O-H bond density for the O II plasma treated surface, whereas the O-H bond surface density was increased relatively to the Zn-O bond density for the N II and CF 4 plasma treated films. The O II plasma was found to partially clean the surface from hydroxyl groups and to expose more Zn cations, which might have caused the enhancement of sensor response by increasing the density of active sites for oxidation/reduction reactions.

  16. Control of electrical transport mechanisms at metal-zinc oxide interfaces by subsurface defect engineering with remote plasma treatment

    NASA Astrophysics Data System (ADS)

    Mosbacker, Howard Lee, IV

    ZnO has received renewed attention in recent years due its exciting properties as a wide band gap semiconductor. ZnO has several advantages over GaN including the availability of substrates, a room temperature excitonic emission, and an environmentally benign chemistry. ZnO applications include efficient blue light emitters, surface acoustic wave devices, transparent conductors, high power transistors, and solid state white lighting. Despite this versatility, several hurdles remain before device realization. Firstly, ZnO is almost always p-type. Although high quality n-type ZnO is abundant, there is no stable and reliable p-type doping scheme. Secondly, research into high quality Ohmic and Schottky contacts has been limited. Although there is an abundance of literature, there has yet to be an attempt to understand the physical and chemical mechanisms at metal- ZnO interfaces. In this work, plasma processing techniques are adopted to ZnO. These cold plasmas allow for room temperature modification of the subsurface. Implanting hydrogen has identified it as a primary n-type dopant responsible for a large fraction of the n-type conductivity. Oxygen plasma treatment has yielded an Ohmic to Schottky conversion by reducing oxygen defects at the near surface. Deposition of metals on clean and ordered surfaces reveal the importance that defects play at the metal-semiconductor interface. Higher concentrations of defects promote reactions. This increased reaction eutectic forming and oxide forming. Understanding the nature of the metal allows for engineering of high quality blocking contacts. These contacts can provide added thermal stability to devices. Subsurface introduction of hydrogen and nitrogen provide a potential roadmap to p-type doping and high quality Schottky contacts. Overall, control of transport properties and contact integrity is achieved by remote plasma processing.

  17. Plasma Characteristics of Large Area Inductively Coupled Plasma System Using Ferrite-Module-Enhanced U-Type Antenna

    NASA Astrophysics Data System (ADS)

    Kim, Kyong Nam; Hyeuk Lim, Jong; Yeom, Geun Young

    2009-11-01

    A ferrite-module-enhanced internal-type linear inductively coupled plasma (ICP) source having multiple U-type antennas operated at 2 MHz has been proposed as a promising candidate to serve as an efficient high-density plasma source for plasma processing areas larger than 2,000×2,300 mm2. When the ICP source was operated at 2 MHz RF power with the ferrite module, high density plasmas on the order of 2.9×1011 cm-3 were obtained at 10 mTorr Ar by applying 4 kW RF power/one U-type antenna; this is 1.5 times higher than the densities obtained at 13.56 MHz without the ferrite module. The higher plasma density obtained with the ICP source operated at 2 MHz with the ferrite module compared with that operated at 13.56 MHz without the ferrite module is related to the magnetic field enhancement caused by the ferrite module. The etch uniformity on a substrate of 2,300×2,000 mm2 at 15 mTorr Ar/O2 (7:3) and about 2.3 kW/U-type antenna was about 11%.

  18. Plasmas in Multiphase Media: Bubble Enhanced Discharges in Liquids and Plasma/Liquid Phase Boundaries

    SciTech Connect

    Kushner, Mark Jay

    2014-07-10

    In this research project, the interaction of atmospheric pressure plasmas with multi-phase media was computationally investigated. Multi-phase media includes liquids, particles, complex materials and porous surfaces. Although this investigation addressed fundamental plasma transport and chemical processes, the outcomes directly and beneficially affected applications including biotechnology, medicine and environmental remediation (e.g., water purification). During this project, we made advances in our understanding of the interaction of atmospheric pressure plasmas in the form of dielectric barrier discharges and plasma jets with organic materials and liquids. We also made advances in our ability to use computer modeling to represent these complex processes. We determined the method that atmospheric pressure plasmas flow along solid and liquid surfaces, and through endoscopic like tubes, deliver optical and high energy ion activation energy to organic and liquid surfaces, and produce reactivity in thin liquid layers, as might cover a wound. We determined the mechanisms whereby plasmas can deliver activation energy to the inside of liquids by sustaining plasmas in bubbles. These findings are important to the advancement of new technology areas such as plasma medicine

  19. Role of plasma enhanced atomic layer deposition reactor wall conditions on radical and ion substrate fluxes

    SciTech Connect

    Sowa, Mark J.

    2014-01-15

    Chamber wall conditions, such as wall temperature and film deposits, have long been known to influence plasma source performance on thin film processing equipment. Plasma physical characteristics depend on conductive/insulating properties of chamber walls. Radical fluxes depend on plasma characteristics as well as wall recombination rates, which can be wall material and temperature dependent. Variations in substrate delivery of plasma generated species (radicals, ions, etc.) impact the resulting etch or deposition process resulting in process drift. Plasma enhanced atomic layer deposition is known to depend strongly on substrate radical flux, but film properties can be influenced by other plasma generated phenomena, such as ion bombardment. In this paper, the chamber wall conditions on a plasma enhanced atomic layer deposition process are investigated. The downstream oxygen radical and ion fluxes from an inductively coupled plasma source are indirectly monitored in temperature controlled (25–190 °C) stainless steel and quartz reactors over a range of oxygen flow rates. Etch rates of a photoresist coated quartz crystal microbalance are used to study the oxygen radical flux dependence on reactor characteristics. Plasma density estimates from Langmuir probe ion saturation current measurements are used to study the ion flux dependence on reactor characteristics. Reactor temperature was not found to impact radical and ion fluxes substantially. Radical and ion fluxes were higher for quartz walls compared to stainless steel walls over all oxygen flow rates considered. The radical flux to ion flux ratio is likely to be a critical parameter for the deposition of consistent film properties. Reactor wall material, gas flow rate/pressure, and distance from the plasma source all impact the radical to ion flux ratio. These results indicate maintaining chamber wall conditions will be important for delivering consistent results from plasma enhanced atomic layer deposition

  20. Remote automatic control scheme for plasma arc cutting of contaminated waste

    SciTech Connect

    Dudar, A.M.; Ward, C.R.; Kriikku, E.M.

    1993-10-01

    The Robotics Development Group at the Savannah River Technology Center has developed and implemented a scheme to perform automatic cutting of metallic contaminated waste. The scheme employs a plasma arc cutter in conjunction with a laser ranging sensor attached to a robotic manipulator called the Telerobot. A software algorithm using proportional control is then used to perturb the robot`s trajectory in such a way as to regulate the plasma arc standoff and the robot`s speed in order to achieve automatic plasma arc cuts. The scheme has been successfully tested on simulated waste materials and the results have been very favorable. This report details the development and testing of the scheme.

  1. Low-temperature in situ formation of Y-Ba-Cu-O high T sub c superconducting thin films by plasma-enhanced metalorganic chemical vapor deposition

    SciTech Connect

    Zhao, J.; Noh, D.W.; Chern, C.; Li, Y.Q.; Norris, P.; Gallois, B.; Kear, B. )

    1990-06-04

    Highly textured, highly dense, superconducting YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} thin films with mirror-like surfaces have been prepared, {ital in} {ital situ}, at a reduced substrate temperature as low as 570 {degree}C by a remote microwave plasma-enhanced metalorganic chemical vapor deposition process (PE-MOCVD). Nitrous oxide was used as the oxidizer gas. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K. PE-MOCVD was carried out in a commercial scale MOCVD reactor.

  2. Atmospheric Plasma-Enhanced Soft Hydrolysis of Southern Pine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The production of fermentable sugars from southern pine using atmospheric plasma (AP) was studied. AP processing in the dielectric barrier discharge (DBD) configuration was coupled with acid hydrolysis in an effort to determine how AP can impact a standard conversion technique. The effects of plas...

  3. Enhancement of the radiation yield in plasma flow switch experiments

    SciTech Connect

    Buff, J. ); Peterkin, R.E. Jr.; Roderick, N.F. ); Degnan, J.H. ); Frese, M.H. ); Turchi, P.J. . Dept. of Aeronautical and Astronautical Engineering)

    1991-06-01

    This paper reports that in a series of experiments that was performed at the Phillips Laboratory (Kirtland Air Force Base, New Mexico), the Shiva Star fast capacitor bank, an inductive store, and a plasma flow switch were used together to deliver multimega-ampere currents with submicrosecond rise times to cylindrical foil loads. Based on two-dimensional MHD simulations with the MACH2 code, the authors previously suggested design modifications to the switch that, when implemented in experiments, substantially increased the fraction of available current that was delivered to the load. The authors have performed a new series of numerical simulations of the plasma flow switch/imploding load system with the goal of discovering a way to boost the total power radiated by the imploding plasmas as it stagnates on the axis of symmetry. The changes to the experimental design that were investigated and which are discussed in this paper include variations of: The shape of the electrodes, size, and mass of the load foil, structure of the axial view vanes, shape and mass of the switching plasma, material from which the load is constructed, the degree to which the load is bowed, and the energy of the capacitor bank. Radiation yields in the range 6-9 TW are predicted for future experiments on Shiva Star.

  4. Enhanced biocompatibility of TiO2 surfaces by highly reactive plasma

    NASA Astrophysics Data System (ADS)

    Junkar, Ita; Kulkarni, Mukta; Drašler, Barbara; Rugelj, Neža; Recek, Nina; Drobne, Damjana; Kovač, Janez; Humpolicek, Petr; Iglič, Aleš; Mozetič, Miran

    2016-06-01

    In the present study the biological response to various nanotopographic features after gaseous plasma treatment were studied. The usefulness of nanostructured surfaces for implantable materials has already been acknowledged, while less is known on the combined effect of nanostructured plasma modified surfaces. In the present work the influence of oxygen plasma treatment on nanostructured titanium oxide (TiO2) surfaces was studied. Characterization of the TiO2 surface chemical composition and morphological features was analyzed after plasma modification by x-ray photoelectron spectroscopy and by scanning electron microscopy while surface wettability was studied with measuring the water contact angle. Cell adhesion and morphology was assessed from images taken with scanning electron microscopy, whereas cell viability was measured with a calorimetric assay. The obtained results showed that oxygen plasma treatment of TiO2 nanotube surfaces significantly influences the adhesion and morphology of osteoblast-like cells in comparison to untreated nanostructured surfaces. Marked changes in surface composition of plasma treated surfaces were observed, as plasma treatment removed hydrocarbon contamination and removed fluorine impurities, which were present due to the electrochemical anodization process. However no differences in wettability of untreated and plasma treated surfaces were noticed. Treatment with oxygen plasma stimulated osteoblast-like cell adhesion and spreading on the nanostructured surface, suggesting the possible use of oxygen plasma surface treatment to enhance osteoblast-like cell response.

  5. Beam current enhancement of microwave plasma ion source utilizing double-port rectangular cavity resonator.

    PubMed

    Lee, Yuna; Park, Yeong-Shin; Jo, Jong-Gab; Yang, J J; Hwang, Y S

    2012-02-01

    Microwave plasma ion source with rectangular cavity resonator has been examined to improve ion beam current by changing wave launcher type from single-port to double-port. The cavity resonators with double-port and single-port wave launchers are designed to get resonance effect at TE-103 mode and TE-102 mode, respectively. In order to confirm that the cavities are acting as resonator, the microwave power for breakdown is measured and compared with the E-field strength estimated from the HFSS (High Frequency Structure Simulator) simulation. Langmuir probe measurements show that double-port cavity enhances central density of plasma ion source by modifying non-uniform plasma density profile of the single-port cavity. Correspondingly, beam current from the plasma ion source utilizing the double-port resonator is measured to be higher than that utilizing single-port resonator. Moreover, the enhancement in plasma density and ion beam current utilizing the double-port resonator is more pronounced as higher microwave power applied to the plasma ion source. Therefore, the rectangular cavity resonator utilizing the double-port is expected to enhance the performance of plasma ion source in terms of ion beam extraction. PMID:22380295

  6. Beam current enhancement of microwave plasma ion source utilizing double-port rectangular cavity resonator

    SciTech Connect

    Lee, Yuna; Park, Yeong-Shin; Jo, Jong-Gab; Yang, J. J.; Hwang, Y. S.

    2012-02-15

    Microwave plasma ion source with rectangular cavity resonator has been examined to improve ion beam current by changing wave launcher type from single-port to double-port. The cavity resonators with double-port and single-port wave launchers are designed to get resonance effect at TE-103 mode and TE-102 mode, respectively. In order to confirm that the cavities are acting as resonator, the microwave power for breakdown is measured and compared with the E-field strength estimated from the HFSS (High Frequency Structure Simulator) simulation. Langmuir probe measurements show that double-port cavity enhances central density of plasma ion source by modifying non-uniform plasma density profile of the single-port cavity. Correspondingly, beam current from the plasma ion source utilizing the double-port resonator is measured to be higher than that utilizing single-port resonator. Moreover, the enhancement in plasma density and ion beam current utilizing the double-port resonator is more pronounced as higher microwave power applied to the plasma ion source. Therefore, the rectangular cavity resonator utilizing the double-port is expected to enhance the performance of plasma ion source in terms of ion beam extraction.

  7. Disinfection of meticillin-resistant Staphylococcus aureus and Staphylococcus epidermidis biofilms using a remote non-thermal gas plasma.

    PubMed

    Cotter, J J; Maguire, P; Soberon, F; Daniels, S; O'Gara, J P; Casey, E

    2011-07-01

    The effective disinfection of hospital surfaces is recognised as an important factor in preventing hospital-acquired infections. The purpose of this study was to quantify the disinfection rate of a novel gas plasma system on clinically relevant biofilms. Clinical isolates of Staphylococcus epidermidis and meticillin-resistant Staphylococcus aureus (MRSA) were grown as biofilms on glass surfaces and tested in a disinfection container remote from the plasma source. The strains used in this study were known to produce substantial quantities of biofilm and average log₁₀ counts were 9.0 and 9.1 cfu/cm(2) for S. epidermidis and MRSA respectively. Counts were reduced by between 4 and 4.5 log₁₀ after 1h of exposure for MRSA and S. epidermidis respectively. More prolonged treatment in the case of MRSA biofilms resulted in a 5.5 log₁₀ reduction after 90 min. Biofilm samples were also placed in medical device packaging bags and similar rates of disinfection were observed. PMID:21601949

  8. Plasma-enhanced mixing and flameholding in supersonic flow

    PubMed Central

    Firsov, Alexander; Savelkin, Konstantin V.; Yarantsev, Dmitry A.; Leonov, Sergey B.

    2015-01-01

    The results of experimental study of plasma-based mixing, ignition and flameholding in a supersonic model combustor are presented in the paper. The model combustor has a length of 600 mm and cross section of 72 mm width and 60 mm height. The fuel is directly injected into supersonic airflow (Mach number M=2, static pressure Pst=160–250 Torr) through wall orifices. Two series of tests are focused on flameholding and mixing correspondingly. In the first series, the near-surface quasi-DC electrical discharge is generated by flush-mounted electrodes at electrical power deposition of Wpl=3–24 kW. The scope includes parametric study of ignition and flame front dynamics, and comparison of three schemes of plasma generation: the first and the second layouts examine the location of plasma generators upstream and downstream from the fuel injectors. The third pattern follows a novel approach of combined mixing/ignition technique, where the electrical discharge distributes along the fuel jet. The last pattern demonstrates a significant advantage in terms of flameholding limit. In the second series of tests, a long discharge of submicrosecond duration is generated across the flow and along the fuel jet. A gasdynamic instability of thermal cavity developed after a deposition of high-power density in a thin plasma filament promotes the air–fuel mixing. The technique studied in this work has weighty potential for high-speed combustion applications, including cold start/restart of scramjet engines and support of transition regime in dual-mode scramjet and at off-design operation. PMID:26170434

  9. Plasma-enhanced mixing and flameholding in supersonic flow.

    PubMed

    Firsov, Alexander; Savelkin, Konstantin V; Yarantsev, Dmitry A; Leonov, Sergey B

    2015-08-13

    The results of experimental study of plasma-based mixing, ignition and flameholding in a supersonic model combustor are presented in the paper. The model combustor has a length of 600 mm and cross section of 72 mm width and 60 mm height. The fuel is directly injected into supersonic airflow (Mach number M=2, static pressure P(st)=160-250 Torr) through wall orifices. Two series of tests are focused on flameholding and mixing correspondingly. In the first series, the near-surface quasi-DC electrical discharge is generated by flush-mounted electrodes at electrical power deposition of W(pl)=3-24 kW. The scope includes parametric study of ignition and flame front dynamics, and comparison of three schemes of plasma generation: the first and the second layouts examine the location of plasma generators upstream and downstream from the fuel injectors. The third pattern follows a novel approach of combined mixing/ignition technique, where the electrical discharge distributes along the fuel jet. The last pattern demonstrates a significant advantage in terms of flameholding limit. In the second series of tests, a long discharge of submicrosecond duration is generated across the flow and along the fuel jet. A gasdynamic instability of thermal cavity developed after a deposition of high-power density in a thin plasma filament promotes the air-fuel mixing. The technique studied in this work has weighty potential for high-speed combustion applications, including cold start/restart of scramjet engines and support of transition regime in dual-mode scramjet and at off-design operation. PMID:26170434

  10. Cavity Enhanced Thomson Scattering for Low Temperature Plasmas

    NASA Astrophysics Data System (ADS)

    Yalin, Azer; Friss, Adam; Lee, Brian; Franka, Isaiah

    2013-09-01

    This contribution describes the design, simulation, and initial experimental development of a novel laser Thomson scattering (LTS) system for measurement of weakly-ionized low temperature plasmas. The LTS approach uses a high power intra-cavity beam of power ~10-100 kW to provide increased scattered photon counts and sensitivity as compared to conventional LTS experiments that use light sources with orders of magnitude lower average power. The high power intra-cavity beam is generated by locking a narrow linewidth source laser to a high-finesse optical cavity via Pound-Drever-Hall locking. The plasma (to be studied) is housed with the high-finesse optical cavity. The high-power source is combined with a detection system comprised of a high-suppression triple monochromator and a low-noise photomultiplier tube used in photon counting mode. We present simulations of signal strengths and scattering spectra including elastic scatter background, detector dark counts, and random (counting) noise contributions. Expected experimental performance is assessed from fits to the simulated data. The number density and electron temperature of a 1010 cm-3 plasma should be accurately measurable with standard deviation of <5% in a measurement time of 5 minutes per wavelength channel. We also present experimental development including characterization of laser locking, and initial Rayleigh and Raman signals which will be used to calibrate the Thomson system.

  11. An improvement of HfO2/Ge interface by in situ remote N2 plasma pretreatment for Ge MOS devices

    NASA Astrophysics Data System (ADS)

    Chi, Xiaowei; Lan, Xiaoling; Lu, Chao; Hong, Haiyang; Li, Cheng; Chen, Songyan; Lai, Hongkai; Huang, Wei; Xu, Jianfang

    2016-03-01

    In situ remote N2 plasma pretreatment of Ge substrate before deposition of HfO2 is proved effective to reduce GeOx interlayer at the HfO2/Ge interface, resulting in a smaller capacitance equivalent oxide thickness, lower interface trap density and leakage current density for the metal/HfO2/n-Ge capacitors. However, it has no obvious impact on the metal/HfO2/p-Ge capacitors, showing a much higher interface trap density than that on n-Ge. The high equivalent permittivity of the HfO2 gate stacks (∼24.2) confirmed the removal of GeOx interlayer by N2 plasma pretreatment. In situ remote N2 plasma pretreatment is demonstrated perspective to make metal/HfO2/n-Ge MOSFET with scaling capacitance equivalent oxide thickness.

  12. Remote detection of the maximum altitude of equatorial ionospheric plasma bubbles

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    1981-01-01

    Nearly 200 post-sunset low-altitude passes of the Alouette 2 and ISIS 1 satellites near the dip equator are studied in order to find the maximum ionospheric plasma bubble altitudes, which are determined by calculating the apex altitude of the magnetic field line passing through the satellite when it is immersed in a bubble. The calculations are made only upon the observation of conjugate hemisphere ionospheric echoes, which result from ducted HF sounder signals that are guided along field-aligned irregularities within the plasma depletion. The maximum bubble altitudes corresponding to the three longitude sectors centered on zero deg, 75 deg W, and 105 deg E, are found to often exceed 1000 km, but seldom 3000 km. The electron density depletions within these field-aligned bubbles, as measured at the point of satellite encounter with the topside ionosphere, are generally less than a factor of two but may exceed a factor of ten.

  13. Microcavity array plasma system for remote chemical processing at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Sung; Hamaguchi, Satoshi; Sakai, Osamu; Park, Sung-Jin; Eden, J. Gary

    2012-06-01

    A microplasma system designed for chemical processing at atmospheric pressure is fabricated and characterized with flowing He/O2 gas mixtures. At the heart of this microcavity dielectric barrier discharge (MDBD) system are two arrays of half-ellipsoidal microcavities engraved by micropowder blasting into dielectric surfaces facing a flowing, low-temperature plasma. Experiments demonstrate that the ignition voltage is reduced, and the spatially averaged optical emission is doubled, for an MDBD flowing plasma array relative to an equivalent system having no microcavities. As an example of the potential of flowing atmospheric microplasma systems for chemical processing, the decomposition of methylene blue (as evidenced by decoloration at 650.2 nm) is shown to proceed at a rate as much as a factor of two greater than that for a non-microcavity equivalent.

  14. Enhancement of the photocatalytic efficiency of WO3 nanoparticles via hydrogen plasma treatment

    NASA Astrophysics Data System (ADS)

    Rahimnejad, Sara; He, Jing Hui; Pan, Feng; Lee, Xue'er; Chen, Wei; Wu, Kai; Xu, Guo Qin

    2014-12-01

    Surface defect engineering is able to effectively enhance the photocatalytic performance of WO3 nanoparticles. In this paper, radio frequency hydrogen plasma was employed to create surface defects on WO3 nanoparticles. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analysis confirmed that hydrogen plasma modification increases the density of oxygen vacancies on the surface of WO3. The broadening of characteristic WO3 peaks in Raman spectra indicates the increase of oxygen vacancies by increasing voltage in hydrogen plasma treatment. The sample treated with hydrogen plasma at 20 volts shows enhancement in photocurrent density by an order of magnitude, attributable to the band-gap narrowing and subsequent increase of quantum yield in the visible range. Consistent results were also obtained from photocatalytic O2 evolution from water oxidation.

  15. Elemental mass spectroscopy of remote surfaces from laser-induced plasmas

    NASA Technical Reports Server (NTRS)

    Situ, W.; DeYoung, R. J.

    1994-01-01

    The elemental mass analysis of laser-produced ions from Al, Cu, Ge, Ag, and a lunar simulant target when irradiated by a 400-mJ, 8-ns, Nd: YAG laser at 1 x 10(exp 9) W/cm(exp 2), is reported. Ions traveled down a 11.1-m evacuated tube to an ion-trap 1-m time-of-flight (TOF) mass spectrometer where an elemental mass spectrum was recorded. The amount of target material removed per laser pulse and the ionization fraction were measured. The ion spatial distribution was measured at 11.1-m distance and found to be near a fourth-power cosine distribution. These results indicate the ability to mass analyze a surface over a distance of many kilometers for lunar and asteroid surface elemental mass analysis by a remote satellite or lunar rover.

  16. A Service-Learning Immersion in a Remote Aboriginal Community: Enhancing Pre-Service Teacher Education

    ERIC Educational Resources Information Center

    Lavery, Shane; Cain, Glenda; Hampton, Patrick

    2014-01-01

    This article examines a service-learning immersion undertaken by pre-service primary teachers in a remote indigenous community and school in Western Australia. The article initially presents the purpose and significance for the immersion in the light of the Australian National Professional Standards for Teachers. The article subsequently outlines…

  17. Enhanced ion particle flux and momentum outward of a plasma ball

    NASA Astrophysics Data System (ADS)

    Makrinich, Gennady; Fruchtman, Amnon

    2013-09-01

    A plasma ball has been produced near the anode in a configuration that, when magnetized, operates as a radial plasma source (RPS). Plasma balls have been studied recently in different configurations. We find that the plasma particle flux outward of the plasma ball is larger than that expected by the Langmuir relation in double layers. The frequency of oscillations of a pendulum is larger than due to gravity only, reflecting the force by the plasma ball. The force by the plasma ball is larger than expected by the model. We address these two questions: the increased ion flux and the increased force relative to the model. We suggest that the Langmuir relation underestimates the ratio of ion to electron flux. We also suggest that the ions gain most of the momentum in the quasi-neutral plasma rather than in the double layer; the impulse enhancement is suggested to result from ion-neutral collisions in the plasma. Partially supported by the Israel Science Foundation, Grant 765/11.

  18. Resonance enhancement of harmonics in metal plasmas using tunable mid-infrared pulses

    NASA Astrophysics Data System (ADS)

    Ganeev, R. A.; Odžak, S.; Milošević, D. B.; Suzuki, M.; Kuroda, H.

    2016-07-01

    The tuning of odd and even high-order harmonics along the resonances of laser-produced plasmas using an optical parametric amplifier of white-light continuum radiation (1250–1400 nm)and its second harmonic is reported. We demonstrate the enhancement of tunable harmonics in the regions of 27, 38, and 47 nm using tin, antimony, and chromium plasmas and discuss the theoretical model of this phenomenon.

  19. Enhanced plasma persistence of therapeutic enzymes by coupling to soluble dextran.

    PubMed Central

    Sherwood, R F; Baird, J K; Atkinson, T; Wiblin, C N; Rutter, D A; Ellwood, D C

    1977-01-01

    Conjugation of carboxypeptidase G and arginase, two enzymes of therapeutic interest, to a soluble dextran significantly enhanced plasma persistence in normal and tumour-bearing mice. A prolonged decrease in arginine concentrations in plasma of tumour-bearing mice was demonstrated by using the dextran-linked arginase. Gel filtration of dextran-enzyme conjugate showed that enzyme activity co-chromatographed as a single peak with carbohydrate, and enzyme was shown to be covalently linked to the dextran. PMID:880251

  20. Plasma-enhanced atomic layer deposition of silicon dioxide films using plasma-activated triisopropylsilane as a precursor

    SciTech Connect

    Jeon, Ki-Moon; Shin, Jae-Su; Yun, Ju-Young; Jun Lee, Sang; Kang, Sang-Woo

    2014-05-15

    The plasma-enhanced atomic layer deposition (PEALD) process was developed as a growth technique of SiO{sub 2} thin films using a plasma-activated triisopropylsilane [TIPS, ((iPr){sub 3}SiH)] precursor. TIPS was activated by an argon plasma at the precursor injection stage of the process. Using the activated TIPS, it was possible to control the growth rate per cycle of the deposited films by adjusting the plasma ignition time. The PEALD technique allowed deposition of SiO{sub 2} films at temperatures as low as 50 °C without carbon impurities. In addition, films obtained with plasma ignition times of 3 s and 10 s had similar values of root-mean-square surface roughness. In order to evaluate the suitability of TIPS as a precursor for low-temperature deposition of SiO{sub 2} films, the vapor pressure of TIPS was measured. The thermal stability and the reactivity of the gas-phase TIPS with respect to water vapor were also investigated by analyzing the intensity changes of the C–H and Si–H peaks in the Fourier-transform infrared spectrum of TIPS.

  1. New simple and rapid remote sensing technique for enhancement and visual interpretation of submerged habitats in coastal environments

    NASA Astrophysics Data System (ADS)

    Moufaddal, W.

    Optical remote sensing data particularly those form Landsat TM and ETM and SPOT has been proven for more than two decades to be capable of resolving of coarse-level habitat distribution in coastal environments However capability of these sensors for interpreting and resolving all major submerged coastal habitats in one color display is confounded by their relative low spectral resolution as well as by limitation of the color mode input to only three wavelength bands In a reef environment for example a true color image blue green and red visible bands in a blue-green-red display from Landsat TM or SPOT is only capable for interpreting coral reef types and bottom changes However information on the other coastal habitats such as seagrasses macro-algae and other submerged aquatic vegetation SAV types are suppressed or lacked because of absence of their spectral signature in this band combination In order to display or to be able to visually interpret SAV habitats the analyst should replace the red visible band with the near-infrared band in the last band combination so that it can reflect the characteristic spectral signature of the aquatic vegetation This adds similar difficulty when one tries to digitally classify a coastal environment with reef substrate types and SAV habitats Unfortunately review of the remote sensing literature reveals that there is no one remote sensing technique to date can visually enhance all substrate habitat types simultaneously The present paper tries to solve this problem through providing a new

  2. Whistler wave-induced ionospheric plasma turbulence: Source mechanisms and remote sensing

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Rooker, L. A.; Whitehurst, L. N.; Lee, M. C.; Ross, L. M.; Sulzer, M. P.; Gonzalez, S.; Tepley, C.; Aponte, N.; See, B. Z.; Hu, K. P.

    2013-10-01

    We report a series of experiments conducted at Arecibo Observatory in the past, aimed at the investigation of 40.75 kHz whistler wave interactions with ionospheric plasmas and the inner radiation belts at L=1.35. The whistler waves are launched from a Naval transmitter (code-named NAU) operating in Aguadilla, Puerto Rico at the frequency and power of 40.75 kHz and 100 kW, respectively. Arecibo radar, CADI, and optical instruments were used to monitor the background ionospheric conditions and detect the induced ionospheric plasma effects. Four-wave interaction processes produced by whistler waves in the ionosphere can excite lower hybrid waves, which can accelerate ionospheric electrons. Furthermore, whistler waves propagating into the magnetosphere can trigger precipitation of energetic electrons from the radiation belts. Radar and optical measurements can distinguish wave-wave and wave-particle interaction processes occurring at different altitudes. Electron acceleration by different mechanisms can be verified from the radar measurements of plasma lines. To facilitate the coupling of NAU-launched 40.75 kHz whistler waves into the ionosphere, we can rely on naturally occurring spread F irregularities to serve as ionospheric ducts. We can also use HF wave-created ducts/artificial waveguides, as demonstrated in our earlier Arecibo experiments and recent Gakona experiments at HAARP. The newly constructed Arecibo HF heater will be employed in our future experiments, which can extend the study of whistler wave interactions with the ionosphere and the magnetosphere/radiation belts as well as the whistler wave conjugate propagation between Arecibo and Puerto Madryn, Argentina.

  3. Heparin-enhanced plasma phospholipase A2 activity and prostacyclin synthesis in patients undergoing cardiac surgery.

    PubMed Central

    Nakamura, H; Kim, D K; Philbin, D M; Peterson, M B; Debros, F; Koski, G; Bonventre, J V

    1995-01-01

    Although eicosanoid production contributes to physiological and pathophysiological consequences of cardiopulmonary bypass (CPB), the mechanisms accounting for the enhanced eicosanoid production have not been defined. Plasma phospholipase A2 (PLA2) activity, 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), and thromboxane B2 (TXB2) levels were measured at various times during cardiac surgery. Plasma PLA2 activity increased after systemic heparinization, before CPB. This was highly correlated with concurrent increases in plasma 6-keto-PGF1 alpha, TXB2 concentrations did not increase with heparin administration but did increase significantly after initiation of CPB. High plasma PLA2 activity, 6-keto-PGF1 alpha, and TXB2 concentrations were measured throughout the CPB period. Protamine, administered to neutralize the heparin, caused an acute reduction of both plasma PLA2 activity and plasma 6-keto-PGF1 alpha, but no change in plasma TXB2 concentrations. Thus the ratio of TXB2 to 6-keto-PGF1 alpha increased significantly after protamine administration. Enhanced plasma PLA2 activity was also measured in patients with lower doses of heparin used clinically for nonsurgical applications. Human plasma PLA2 was identified as group II PLA2 by its sensitivity to deoxycholate and dithiothreitol, its substrate specificity, and its elution characteristics on heparin affinity chromatography. Heparin addition to PMNs in vitro resulted in dose-dependent increases in cellular PLA2 activity and release of PLA2. The PLA2 released from the PMN had characteristics similar to those of post-heparin plasma PLA2. In conclusion, plasma PLA2 activity and 6-keto-PGF1 alpha concentrations are markedly enhanced with systemic heparinization. Part of the anticoagulant and vasodilating effects of heparin may be due to increased plasma prostacyclin (PGI2) levels. In addition the pulmonary vasoconstriction sometimes associated with protamine infusion during cardiac surgery might be due to decreased

  4. Atmospheric pressure plasma enhanced spatial ALD of silver

    SciTech Connect

    Bruele, Fieke J. van den Smets, Mireille; Illiberi, Andrea; Poodt, Paul; Buskens, Pascal; Roozeboom, Fred

    2015-01-15

    The authors have investigated the growth of thin silver films using a unique combination of atmospheric process elements: spatial atomic layer deposition and an atmospheric pressure surface dielectric barrier discharge plasma source. Silver films were grown on top of Si substrates with good purity as revealed by resistivity values as low as 18 μΩ cm and C- and F-levels below detection limits of energy dispersive x-ray analysis. The growth of the silver films starts through the nucleation of islands that subsequently coalesce. The authors show that the surface island morphology is dependent on surface diffusion, which can be controlled by temperature within the deposition temperature range of 100–120 °C.

  5. Screening Enhancement of Energy Equipartition in a Strongly Magnetized Nonneutral Plasma.

    NASA Astrophysics Data System (ADS)

    Bollinger, J.; Dubin, D.

    2004-11-01

    An analogy is uncovered between the nuclear reaction rate in a dense plasma and the energy equipartition rate in a strongly-correlated (Γ = e^2 / aT ≫ 1) strongly-magnetized (κ = e^2 Ωc / \\overlinev T ≫ 1) nonneutral plasma. [Here \\overlinev = √T/m.] When κ ≫ 1, cyclotron energy is an adiabatic invariant. This energy is shared with other degrees of freedom only through rare close collisions that break the invariant. If Γ > 1, the probability of such close collisions is greatly enhanced because surrounding charges screen the colliding pair. In the regime Γ < κ^(2/5), we find that the equipartition rate ν defined by d Tc /dt = ν (T - T_c) (where Tc is the cyclotron temperature) is the rate without screening(M.E. Glinsky et al.), Phys. Fluids B 4, 1156 (1992). multiplied by an enhancement factor f (Γ). Interestingly, f(Γ ) is identical to the enhancement factor appearing in the theory of nuclear reaction rates in dense plasmas.(E.E. Salpeter and H. Van Horn, Ap. J. 155), 183 (1969). We present molecular dynamics simulations of equipartition. Rate enhancements of up to 10^10 are measured. The greatly enhanced rate may help to explain recent experiments that observed rapid equipartition in a Be^+ plasma.(Jensen et al., submitted to PRL. See also the adjacent poster.)

  6. Remote use of distributed robotics resources to enhance technology development and insertion

    SciTech Connect

    Harrigan, R.W.; McDonald, M.J.; Davies, B.R.

    1994-04-01

    This paper describes Virtual Collaborative Environments (VCEs), an information architecture that enables remote sharing of mechatronic (intelligent electrochemical devices) resources. This architecture will leverage the proposed National Information Infrastructure (NII) or Information Highway to share valuable resources and reduce product-to-market cycles. Benefits of sharing mechatronic resources with VCEs are explored. An existing prototype VCE is described and experimental and illustrative results from using the prototype VCE system are discussed.

  7. Security analysis and enhancements of an effective biometric-based remote user authentication scheme using smart cards.

    PubMed

    An, Younghwa

    2012-01-01

    Recently, many biometrics-based user authentication schemes using smart cards have been proposed to improve the security weaknesses in user authentication system. In 2011, Das proposed an efficient biometric-based remote user authentication scheme using smart cards that can provide strong authentication and mutual authentication. In this paper, we analyze the security of Das's authentication scheme, and we have shown that Das's authentication scheme is still insecure against the various attacks. Also, we proposed the enhanced scheme to remove these security problems of Das's authentication scheme, even if the secret information stored in the smart card is revealed to an attacker. As a result of security analysis, we can see that the enhanced scheme is secure against the user impersonation attack, the server masquerading attack, the password guessing attack, and the insider attack and provides mutual authentication between the user and the server. PMID:22899887

  8. Remote sensing of the magnetospheric plasma by means of whistler mode signals

    SciTech Connect

    Carpenter, D.L.

    1988-08-01

    The type of data obtained by the whistler mode probing of the magnetosphere are discussed together with various whistler probing methods and the uses of whistler data. Consideration is given to the intercomparison of whistler results with data from satellites and incoherent scatter radar; the role of whistlers in various magnetosphere/ionosphere probing experiments; the results of whistler studies of geomagnetic-field-aligned propagation 'ducts' and their excitation by ground sources; the direction finding using a tracking receiver/direction finder; the use of whistlers to measure hot plasma effects; and the phase measurements of whistler mode signals, with special consideration given to the application of a new phase measurement method to Siple signals. 76 references.

  9. Plasma etching of SiO2 using remote-type pin-to-plate dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Park, Jae Beom; Kyung, Se Jin; Yeom, Geun Young

    2008-10-01

    Atmospheric pressure plasma etching of SiO2 was examined using a modified remote-type dielectric barrier discharge (DBD), called "pin-to-plate DBD." The effect of adding four gases CF4, C4F8, O2, and Ar to the base gas mixture containing N2 (60 slm) (slm denotes standard liters per minute)/NF3 (600 SCCM) (SCCM denotes cubic centimeter per minute at STP) on the SiO2 etch characteristics was investigated. The results showed that the SiO2 etch rate decreased continuously with increasing C4F8 (200-800 SCCM) addition, whereas the SiO2 etch rate increased with increasing CF4 (1-10 slm) addition up to 7 slm CF4. This increase in the SiO2 etch rate up to 7 slm CF4 was attributed to the effective removal of Si in SiO2 by F atoms through the removal of oxygen in SiO2 by carbon in the CFX in the plasma. However, the decrease in SiO2 etch rate with further increases in CF4 flow rate above 7 slm was attributed to the formation of a thick C-F polymer layer on the SiO2 surface. A SiO2 etch rate of approximately 243 nm/min was obtained with a gas mixture of N2 (60 slm)/NF3 (600 SCCM)/CF4 (7 slm), and an input voltage and operating frequency to the source of 10 kV and 30 kHz, respectively. The addition of 200 SCCM Ar to the above gas mixture increased the SiO2 etch rate to approximately 263 nm/min. This is possibly due to the increased ionization and dissociation of reactive species through penning ionization of Ar.

  10. Nonthermal Atmospheric Pressure Plasma Enhances Mouse Limb Bud Survival, Growth, and Elongation

    PubMed Central

    Chernets, Natalie; Zhang, Jun; Steinbeck, Marla J.; Kurpad, Deepa S.; Koyama, Eiki; Friedman, Gary

    2015-01-01

    The enhanced differentiation of mesenchymal cells into chondrocytes or osteoblasts is of paramount importance in tissue engineering and regenerative therapies. A newly emerging body of evidence demonstrates that appendage regeneration is dependent on reactive oxygen species (ROS) production and signaling. Thus, we hypothesized that mesenchymal cell stimulation by nonthermal (NT)-plasma, which produces and induces ROS, would (1) promote skeletal cell differentiation and (2) limb autopod development. Stimulation with a single treatment of NT-plasma enhanced survival, growth, and elongation of mouse limb autopods in an in vitro organ culture system. Noticeable changes included enhanced development of digit length and definition of digit separation. These changes were coordinated with enhanced Wnt signaling in the distal apical epidermal ridge (AER) and presumptive joint regions. Autopod development continued to advance for approximately 144 h in culture, seemingly overcoming the negative culture environment usually observed in this in vitro system. Real-time quantitative polymerase chain reaction analysis confirmed the up-regulation of chondrogenic transcripts. Mechanistically, NT-plasma increased the number of ROS positive cells in the dorsal epithelium, mesenchyme, and the distal tip of each phalange behind the AER, determined using dihydrorhodamine. The importance of ROS production/signaling during development was further demonstrated by the stunting of digital outgrowth when anti-oxidants were applied. Results of this study show NT-plasma initiated and amplified ROS intracellular signaling to enhance development of the autopod. Parallels between development and regeneration suggest that the potential use of NT-plasma could extend to both tissue engineering and clinical applications to enhance fracture healing, trauma repair, and bone fusion. PMID:25102046

  11. Nonthermal atmospheric pressure plasma enhances mouse limb bud survival, growth, and elongation.

    PubMed

    Chernets, Natalie; Zhang, Jun; Steinbeck, Marla J; Kurpad, Deepa S; Koyama, Eiki; Friedman, Gary; Freeman, Theresa A

    2015-01-01

    The enhanced differentiation of mesenchymal cells into chondrocytes or osteoblasts is of paramount importance in tissue engineering and regenerative therapies. A newly emerging body of evidence demonstrates that appendage regeneration is dependent on reactive oxygen species (ROS) production and signaling. Thus, we hypothesized that mesenchymal cell stimulation by nonthermal (NT)-plasma, which produces and induces ROS, would (1) promote skeletal cell differentiation and (2) limb autopod development. Stimulation with a single treatment of NT-plasma enhanced survival, growth, and elongation of mouse limb autopods in an in vitro organ culture system. Noticeable changes included enhanced development of digit length and definition of digit separation. These changes were coordinated with enhanced Wnt signaling in the distal apical epidermal ridge (AER) and presumptive joint regions. Autopod development continued to advance for approximately 144 h in culture, seemingly overcoming the negative culture environment usually observed in this in vitro system. Real-time quantitative polymerase chain reaction analysis confirmed the up-regulation of chondrogenic transcripts. Mechanistically, NT-plasma increased the number of ROS positive cells in the dorsal epithelium, mesenchyme, and the distal tip of each phalange behind the AER, determined using dihydrorhodamine. The importance of ROS production/signaling during development was further demonstrated by the stunting of digital outgrowth when anti-oxidants were applied. Results of this study show NT-plasma initiated and amplified ROS intracellular signaling to enhance development of the autopod. Parallels between development and regeneration suggest that the potential use of NT-plasma could extend to both tissue engineering and clinical applications to enhance fracture healing, trauma repair, and bone fusion. PMID:25102046

  12. Control of interface nanoscale structure created by plasma-enhanced chemical vapor deposition.

    PubMed

    Peri, Someswara R; Akgun, Bulent; Satija, Sushil K; Jiang, Hao; Enlow, Jesse; Bunning, Timothy J; Foster, Mark D

    2011-09-01

    Tailoring the structure of films deposited by plasma-enhanced chemical vapor deposition (PECVD) to specific applications requires a depth-resolved understanding of how the interface structures in such films are impacted by variations in deposition parameters such as feed position and plasma power. Analysis of complementary X-ray and neutron reflectivity (XR, NR) data provide a rich picture of changes in structure with feed position and plasma power, with those changes resolved on the nanoscale. For plasma-polymerized octafluorocyclobutane (PP-OFCB) films, a region of distinct chemical composition and lower cross-link density is found at the substrate interface for the range of processing conditions studied and a surface layer of lower cross-link density also appears when plasma power exceeds 40 W. Varying the distance of the feed from the plasma impacts the degree of cross-linking in the film center, thickness of the surface layer, and thickness of the transition region at the substrate. Deposition at the highest power, 65 W, both enhances cross-linking and creates loose fragments with fluorine content higher than the average. The thickness of the low cross-link density region at the air interface plays an important role in determining the width of the interface built with a layer subsequently deposited atop the first. PMID:21875044

  13. Space charge enhanced plasma gradient effects on satellite electric field measurements

    NASA Technical Reports Server (NTRS)

    Diebold, Dan; Hershkowitz, Noah; Dekock, J.; Intrator, T.; Hsieh, M-K.

    1991-01-01

    It has been recognized that plasma gradients can cause error in magnetospheric electric field measurements made by double probes. Space charge enhanced Plasma Gradient Induced Error (PGIE) is discussed in general terms, presenting the results of a laboratory experiment designed to demonstrate this error, and deriving a simple expression that quantifies this error. Experimental conditions were not identical to magnetospheric conditions, although efforts were made to insure the relevant physics applied to both cases. The experimental data demonstrate some of the possible errors in electric field measurements made by strongly emitting probes due to space charge effects in the presence of plasma gradients. Probe errors in space and laboratory conditions are discussed, as well as experimental error. In the final section, theoretical aspects are examined and an expression is derived for the maximum steady state space charge enhanced PGIE taken by two identical current biased probes.

  14. Electromagnetic energy density manipulation and enhancement in a relativistic plasma: the role of relativistic nonlinearities

    SciTech Connect

    Pegoraro, F.

    2009-11-10

    A tutorial presentation is given describing the nature and the effects of relativistic nonlinearities in a plasma and indicating how they can be exploited in order to manipulate and enhance locally the energy density of the electromagnetic fields. The mathematical formulation and the examples presented are chosen from results available in the scientific literature.

  15. Noise Suppression and Enhanced Focusability in Plasma Raman Amplifier with Multi-frequency Pump

    SciTech Connect

    A.A. Balakin; G.M. Fraiman; N.J. Fisch; V.M. Malkin

    2003-06-16

    Laser pulse compression/amplification through Raman backscattering in plasmas can be facilitated by using multi-frequency pump laser beams. The efficiency of amplification is increased by suppressing the Raman instability of thermal fluctuations and seed precursors. Also the focusability of the amplified radiation is enhanced due to the suppression of large-scale longitudinal speckles in the pump wave structure.

  16. Growth enhancement effects of radish sprouts: atmospheric pressure plasma irradiation vs. heat shock

    NASA Astrophysics Data System (ADS)

    Sarinont, T.; Amano, T.; Kitazaki, S.; Koga, K.; Uchida, G.; Shiratani, M.; Hayashi, N.

    2014-06-01

    We compare growth enhancement effects due to atmospheric air dielectric barrier discharge plasma irradiation and heat shock to seeds of radish sprouts (Raphanus sativus L.). Interactions between radicals and seeds in a short duration of 3 min. lead to the growth enhancement of radish sprouts in a long term of 7 days and the maximum average length is 3.7 times as long as that of control. The growth enhancement effects become gradually weak with time, and hence the ratio of the average length for plasma irradiation to that for control decreases from 3.7 for the first day to 1.3 for 7 day. The average length for heat shock of 60°C for 10 min. and 100°C for 3 min. is longer than that for control, and the maximum average length is 1.3 times as long as that of control. Heat shock has little contribution to the growth enhancement due to plasma irradiation, because the maximum temperature due to plasma irradiation is less than 60°C.

  17. Localized microwave pulsed plasmas for ignition and flame front enhancement

    NASA Astrophysics Data System (ADS)

    Michael, James Bennett

    Modern combustor technologies require the ability to match operational parameters to rapidly changing demands. Challenges include variable power output requirements, variations in air and fuel streams, the requirement for rapid and well-controlled ignition, and the need for reliability at low fuel mixture fractions. Work on subcritical microwave coupling to flames and to weakly ionized laser-generated plasmas has been undertaken to investigate the potential for pulsed microwaves to allow rapid combustion control, volumetric ignition, and leaner combustion. Two strategies are investigated. First, subcritical microwaves are coupled to femtosecond laser-generated ionization to ignite methane/air mixtures in a quasi-volumetric fashion. Total energy levels are comparable to the total minimum ignition energies for laser and spark discharges, but the combined strategy allows a 90 percent reduction in the required laser energy. In addition, well-defined multi-dimensional ignition patterns are designated with multiple laser passes. Second, microwave pulse coupling to laminar flame fronts is achieved through interaction with chemiionization-produced electrons in the reaction zone. This energy deposition remains well-localized for a single microwave pulse, resulting in rapid temperature rises of greater than 200 K and maintaining flame propagation in extremely lean methane/air mixtures. The lean flammability limit in methane/air mixtures with microwave coupling has been decreased from an equivalence ratio 0.6 to 0.3. Additionally, a diagnostic technique for laser tagging of nitrogen for velocity measurements is presented. The femtosecond laser electronic excitation tagging (FLEET) technique utilizes a 120 fs laser to dissociate nitrogen along a laser line. The relatively long-lived emission from recombining nitrogen atoms is imaged with a delayed and fast-gated camera to measure instantaneous velocities. The emission strength and lifetime in air and pure nitrogen allow

  18. Enhancing Remotely Sensed TIR Data for Public Health Applications: Is West Nile Virus Heat-Related?

    NASA Astrophysics Data System (ADS)

    Weng, Q.; Liu, H.; Jiang, Y.

    2014-12-01

    Public health studies often require thermal infrared (TIR) images at both high temporal and spatial resolution to retrieve LST. However, currently, no single satellite sensors can deliver TIR data at both high temporal and spatial resolution. This technological limitation prevents the wide usage of remote sensing data in epidemiological studies. To solve this issue, we have developed a few image fusion techniques to generate high temporally-resolved image data. We downscaled GOES LST data to 15-minute 1-km resolution to assess community-based heat-related risk in Los Angeles County, California and simulated ASTER datasets by fusing ASTER and MODIS data to derive biophysical variables, including LST, NDVI, and normalized difference water index, to examine the effects of those environmental characteristics on WNV outbreak and dissemination. A spatio-temporal analysis of WNV outbreak and dissemination was conducted by synthesizing the remote sensing variables and mosquito surveillance data, and by focusing on WNV risk areas in July through September due to data sufficiency of mosquito pools. Moderate- and high-risk areas of WNV infections in mosquitoes were identified for five epidemiological weeks. These identified WNV-risk areas were then collocated in GIS with heat hazard, exposure, and vulnerability maps to answer the question of whether WNV is a heat related virus. The results show that elevation and built-up conditions were negatively associated with the WNV propagation, while LST positively correlated with the viral transmission. NDVI was not significantly associated with WNV transmission. San Fernando Valley was found to be the most vulnerable to mosquito infections of WNV. This research provides important insights into how high temporal resolution remote sensing imagery may be used to study time-dependant events in public health, especially in the operational surveillance and control of vector-borne, water-borne, or other epidemic diseases.

  19. Growing aluminum nitride films by Plasma-Enhanced Atomic Layer Deposition at low temperatures

    NASA Astrophysics Data System (ADS)

    Tarala, V. A.; Altakhov, A. S.; Martens, V. Ya; Lisitsyn, S. V.

    2015-11-01

    Aluminum nitride films have been grown by Plasma-Enhanced Atomic Layer Deposition method. It was found that at temperatures of 250 °C and 280 °C increase of the plasma exposure step duration over 6 s, as well as increase of reactor purge step duration over 1 s does not affect the growth rate, however, it affects the microstructure of the films. It was found that crystalline aluminum nitride films deposit with plasma exposure duration over 10 s and the reactor purging over 10 s. When the temperature drops the increase of reactor purge step duration and plasma exposure step duration over 20 s is required for crystalline AlN film growth.

  20. Plasma cutoff and enhancement of radiative transitions in dense stellar matter

    NASA Astrophysics Data System (ADS)

    Shternin, P. S.; Yakovlev, D. G.

    2009-06-01

    We study plasma effects on radiative transitions (e.g., decay of excited states of atoms or atomic nuclei) in a dense plasma at the transition frequencies ω≲ωp (where ωp is the electron plasma frequency). The decay goes through four channels—the emission of real transverse and longitudinal plasmons as well as the emission of virtual transverse and longitudinal plasmons with subsequent absorption of such plasmons by the plasma. The emission of real plasmons dies out at ω≤ωp, but the processes with virtual plasmons strongly enhance the radiative decay. Applications of these results to radiative processes in white dwarf cores and neutron star envelopes are discussed.

  1. Enhanced Field Emission from Argon Plasma-Treated Ultra-sharp α-Fe2O3Nanoflakes

    PubMed Central

    2009-01-01

    Hematite nanoflakes have been synthesized by a simple heat oxide method and further treated by Argon plasmas. The effects of Argon plasma on the morphology and crystal structures of nanoflakes were investigated. Significant enhancement of field-induced electron emission from the plasma-treated nanoflakes was observed. The transmission electron microscopy investigation shows that the plasma treatment effectively removes amorphous coating and creates plenty of sub-tips at the surface of the nanoflakes, which are believed to contribute the enhancement of emission. This work suggests that plasma treatment technique could be a direct means to improve field-emission properties of nanostructures. PMID:20596290

  2. Enhancement of emission currents in plasma electron sources based on a low-pressure arc discharge

    NASA Astrophysics Data System (ADS)

    Koval, T. V.; Devyatkov, V. N.; Hung, Nguyen Bao

    2015-11-01

    The paper reports on a theoretical and experimental study of the discharge plasma generation with an enhanced electron emission current in a plasma electron source based on a low-pressure arc discharge with a grid-stabilized plasma emission boundary. The source operates at a pressure in the working chamber of p = 0.02-0.05 Pa (Ar), accelerating voltage of up to Ua = 10 kV, and longitudinal magnetic field for electron beam transport of up to Bz = 0.1 T. The experiments show that in the mode of electron emission from the plasma, the voltage Ud between the cathode and grid electrode changes its sign. The numerical simulation demonstrates that the plasma potential and voltage Ud depend on the electric field penetrating from the acceleration gap into the discharge region through the grid meshes, and on the discharge current, gas pressure, geometric transparency of the grid, and gas kind. It is shown that the main mechanisms responsible for the increase in the discharge current and electron emission current from the plasma are associated with secondary ion-electron emission from the emission electrode and with positive feedback between the region of cathode plasma generation and the channel of electron beam transport.

  3. Formation and characterization of high-density FeSi nanodots on SiO2 induced by remote H2 plasma

    NASA Astrophysics Data System (ADS)

    Zhang, Hai; Makihara, Katsunori; Ohta, Akio; Ikeda, Mitsuhisa; Miyazaki, Seiichi

    2016-01-01

    We demonstrated the formation of high-density iron silicide nanodots (NDs) on thermally grown SiO2 by exposing an electron-beam-evaporated Fe/amorphous-Si/Fe (Fe/a-Si/Fe) trilayer stack to remote H2 plasma without any external heating and characterized their silicidation state and crystalline phase. After the remote H2 plasma exposure, the formation of NDs with an areal density of ˜4.3 × 1011 cm-2 and an average height of ˜7.1 nm was confirmed. X-ray photoelectron spectroscopy (XPS) analyses indicate silicidation reaction induced by the remote H2 plasma exposure, which was accompanied by the agglomeration of Fe and Si atoms on the SiO2 surface. The formation of a crystalline β-FeSi2 phase was confirmed by Raman scattering spectroscopy and XRD pattern measurements. The electrical separation among the β-FeSi2 NDs was confirmed from changes in surface potential due to charging of the dots. The surface potential of the NDs changed in a stepwise manner with respect to the tip voltage because of multistep electron injection into and extraction from the semiconductor β-FeSi2 NDs.

  4. {lambda}{sub c} Enhancement from Strongly Coupled Quark-Gluon Plasma

    SciTech Connect

    Lee, Su Houng; Ohnishi, Kazuaki; Yasui, Shigehiro; Yoo, In-Kwon; Ko, Che Ming

    2008-06-06

    We propose the enhancement of {lambda}{sub c} as a novel quark-gluon plasma signal in heavy ion collisions at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider. Assuming a stable bound diquark state in the strongly coupled quark-gluon plasma near the critical temperature, we argue that the direct two-body collision between a c quark and a [ud] diquark would lead to an enhanced {lambda}{sub c} production in comparison with the normal three-body collision among independent c, u, and d quarks. In the coalescence model, we find that the {lambda}{sub c}/D yield ratio is enhanced substantially due to the diquark correlation.

  5. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    NASA Astrophysics Data System (ADS)

    Reis, Rackel; Dumée, Ludovic F.; Tardy, Blaise L.; Dagastine, Raymond; Orbell, John D.; Schutz, Jürg A.; Duke, Mikel C.

    2016-07-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties.

  6. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    PubMed Central

    Reis, Rackel; Dumée, Ludovic F.; Tardy, Blaise L.; Dagastine, Raymond; Orbell, John D.; Schutz, Jürg A.; Duke, Mikel C.

    2016-01-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties. PMID:27363670

  7. Rice (Oryza sativa L.) Seed Sterilization and Germination Enhancement via Atmospheric Hybrid Nonthermal Discharge Plasma.

    PubMed

    Khamsen, Natthaporn; Onwimol, Damrongvudhi; Teerakawanich, Nithiphat; Dechanupaprittha, Sanchai; Kanokbannakorn, Weerawoot; Hongesombut, Komsan; Srisonphan, Siwapon

    2016-08-01

    We designed a system to produce atmospheric hybrid cold-discharge plasma (HCP) based on microcorona discharge on a single dielectric barrier and applied it to inactivate microorganisms that commonly attach the rice seed husk. The cold-plasma treatment modified the surface of the rice seeds, resulting in accelerated germination and enhanced water imbibition. The treatment can operate under air-based ambient conditions without the need for a vacuum. The cold-plasma treatment completely inactivated pathogenic fungi and other microorganisms, enhancing the germination percentage and seedling quality. The final germination percentage of the treated rice seeds was ∼98%, whereas that of the nontreated seeds was ∼90%. Microcorona discharge on a single dielectric barrier provides a nonaggressive cold plasma that can be applied to organic materials without causing thermal and electrical damage. The hybrid nonthermal plasma is cost effective and consumes relatively little power, making it suitable for the surface sterilization and disinfection of organic and biological materials with large-scale compatibility. PMID:27404121

  8. Plasma nano-modification of poly(ethylene terephthalate) fabric for pigment adhesion enhancement.

    PubMed

    Pransilp, Porntepin; Kiatkamjornwong, Suda; Bhanthumnavin, Worawan; Paosawatyanyong, Boonchoat

    2012-01-01

    Poly(ethylene terephthalate) (PET) fabrics were modified by treating with radio frequency (RF) plasma of different gases, including argon (Ar), nitrogen (N2), oxygen (O2) and sulfur hexafluoride (SF6), under varied power (50-150 watt) and time period (0.5-20 min). Observations indicated that plasma has affected the morphology and roughness of PET fiber surface in the nano-scale level. After plasma treatment, test patterns were printed by inkjet printer directly onto the sample surface. The enhancement of color printing performance on PET fabric by plasma treatment was evaluated by color spectroscopy. The surface nano-modified PET fabrics by Ar, N2, O2, and SF6 plasmas all exhibited enhanced color yield. AFM, SEM, FTIR-ATR and XPS results suggested that the improved pigment color yield was neither clearly contributed by the wettability of the fabrics nor the polar group induced onto the fiber surfaces but rather mainly by the alteration of surface roughness. PMID:22524006

  9. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification.

    PubMed

    Reis, Rackel; Dumée, Ludovic F; Tardy, Blaise L; Dagastine, Raymond; Orbell, John D; Schutz, Jürg A; Duke, Mikel C

    2016-01-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties. PMID:27363670

  10. LED lamp or bulb with remote phosphor and diffuser configuration with enhanced scattering properties

    SciTech Connect

    Tong, Tao; Le Toquin, Ronan; Keller, Bernd; Tarsa, Eric; Youmans, Mark; Lowes, Theodore; Medendorp, Jr., Nicholas W; Van De Ven, Antony; Negley, Gerald

    2014-11-11

    An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and an optical cavity. The optical cavity comprises a phosphor carrier having a conversions material and arranged over an opening to the cavity. The phosphor carrier comprises a thermally conductive transparent material and is thermally coupled to the heat sink structure. An LED based light source is mounted in the optical cavity remote to the phosphor carrier with light from the light source passing through the phosphor carrier. A diffuser dome is included that is mounted over the optical cavity, with light from the optical cavity passing through the diffuser dome. The properties of the diffuser, such as geometry, scattering properties of the scattering layer, surface roughness or smoothness, and spatial distribution of the scattering layer properties may be used to control various lamp properties such as color uniformity and light intensity distribution as a function of viewing angle.

  11. TOPICAL REVIEW: A review of plasma enhanced chemical vapour deposition of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Meyyappan, M.

    2009-11-01

    Plasma enhanced chemical vapour deposition (PECVD) has been widely discussed in the literature for the growth of carbon nanotubes (CNTs) and carbon nanofibres (CNFs) in recent years. Advantages claimed include lower growth temperatures relative to thermal CVD and the ability to grow individual, free-standing, vertical CNFs instead of tower-like structures or ensembles. This paper reviews the current status of the technology including equipment, plasma chemistry, diagnostics and modelling, and mechanisms. Recent accomplishments include PECVD of single-walled CNTs and growth at low temperatures for handling delicate substrates such as glass.

  12. Contact potential induced enhancement of magnetization in polyaniline coated nanomagnetic iron oxides by plasma polymerization

    NASA Astrophysics Data System (ADS)

    Sethulakshmi, N.; Sooraj, V.; Sajeev, U. S.; Nair, Swapna S.; Narayanan, T. N.; Joy, Lija K.; Joy, P. A.; Ajayan, P. M.; Anantharaman, M. R.

    2013-10-01

    The present work derives motivation from the so called surface/interfacial magnetism in core shell structures and commercial samples of Fe3O4 and γ Fe2O3 with sizes ranging from 20 to 30 nm were coated with polyaniline using plasma polymerization and studied. The High Resolution Transmission Electron Microscopy images indicate a core shell structure after polyaniline coating and exhibited an increase in saturation magnetization by 2 emu/g. For confirmation, plasma polymerization was performed on maghemite nanoparticles which also exhibited an increase in saturation magnetization. This enhanced magnetization is rather surprising and the reason is found to be an interfacial phenomenon resulting from a contact potential.

  13. Influence of annular magnet on discharge characteristics in enhanced glow discharge plasma immersion ion implantation

    SciTech Connect

    Li Liuhe; Wang Zhuo; Lu Qiuyuan; Fu, Ricky K. Y.; Chu, Paul K.; Pang Enjing; Dun Dandan; He Fushun; Li Fen

    2011-01-10

    A permanent annular magnet positioned at the grounded anode alters the discharge characteristics in enhanced glow discharge plasma immersion ion implantation (EGD-PIII). The nonuniform magnetic field increases the electron path length and confines electron motion due to the magnetic mirror effect and electron-neutral collisions thus occur more frequently. The plasma potential and ion density measured by a Langmuir probe corroborate that ionization is improved near the grounded anode. This hybrid magnetic field EGD-PIII method is suitable for implantation of gases with low ionization rates.

  14. A dielectric-barrier discharge enhanced plasma brush array at atmospheric pressure

    SciTech Connect

    Li Xuemei; Zhan Xuefang; Yuan Xin; Zhao Zhongjun; Yan Yanyue; Duan Yixiang; Tang Jie

    2013-07-15

    This study developed a large volume cold atmospheric plasma brush array, which was enhanced by a dielectric barrier discharge by integrating a pair of DC glow discharge in parallel. A platinum sheet electrode was placed in the middle of the discharge chamber, which effectively reduced the breakdown voltage and working voltage. Emission spectroscopy diagnosis indicated that many excited argon atoms were distributed almost symmetrically in the lateral direction of the plasma. The concentration variations of reactive species relative to the gas flow rate and discharge current were also examined.

  15. Short-term calorie restriction enhances adult hippocampal neurogenesis and remote fear memory in a Ghsr-dependent manner

    PubMed Central

    Hornsby, Amanda K.E.; Redhead, Yushi T.; Rees, Daniel J.; Ratcliff, Michael S.G.; Reichenbach, Alex; Wells, Timothy; Francis, Lewis; Amstalden, Katia; Andrews, Zane B.; Davies, Jeffrey S.

    2016-01-01

    The beneficial effects of calorie restriction (CR) have been described at both organismal and cellular levels in multiple organs. However, our understanding of the causal mediators of such hormesis is poorly understood, particularly in the context of higher brain function. Here, we show that the receptor for the orexigenic hormone acyl-ghrelin, the growth hormone secretagogue receptor (Ghsr), is enriched in the neurogenic niche of the hippocampal dentate gyrus (DG). Acute elevation of acyl-ghrelin levels by injection or by overnight CR, increased DG levels of the neurogenic transcription factor, Egr-1. Two weeks of CR increased the subsequent number of mature newborn neurons in the DG of adult wild-type but not Ghsr−/− mice. CR wild-type mice also showed improved remote contextual fear memory. Our findings suggest that Ghsr mediates the beneficial effects of CR on enhancing adult hippocampal neurogenesis and memory. PMID:26460782

  16. Enhancement of Functional Ceramic Coating Performance by Gas Tunnel Type Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Kobayashi, Akira

    2016-02-01

    A high-precision plasma system has been pursued for advanced thermal processing. The gas tunnel type plasma jet device developed by the author exhibits high energy density and also high efficiency. Among its various applications is the plasma spraying of ceramics such as Al2O3 and ZrO2. The performance of these ceramic coatings is superior to conventional ones. Properties such as the mechanical and chemical properties of the zirconia coatings were reported in previous studies. In this study, the enhancement of the performance of functional ceramic coatings by the gas tunnel type plasma spraying method was carried out using different powders. Results show that the alumina/zirconia composite system exhibited improvements of mechanical properties and corrosion resistance. The alumina/zirconia composite coating has the potential for use as a high functionally graded thermal barrier coating. Another application of the gas tunnel type plasma is for surface modification of metals. As an example, TiN films were formed in 5 s and, thick TiN coatings were easily obtained by gas tunnel type plasma reactive spraying.

  17. The evolution of carbon nanotubes during their growth by plasma enhanced chemical vapor deposition.

    PubMed

    Wang, Hengzhi; Ren, Z F

    2011-10-01

    During the growth of carbon nanotubes (CNTs) by plasma enhanced chemical vapor deposition (PECVD), plasma etching is the crucial factor that determines the growth mode and alignment of the CNTs. Focusing on a thin catalyst coating (Ni = 5 nm), this study finds that the CNT growth by PECVD goes through three stages from randomly entangled (I-CNTs) to partially aligned (II-CNTs) to fully aligned (III-CNTs). The I-CNTs and II-CNTs are mostly etched away by the plasma as time goes by ending up with III-CNTs as the only product when growth time is long enough. However, with a thickness of the catalyst coating of 10 nm or more, neither I-CNTs nor II-CNTs are produced, but III-CNTs are the only type of CNTs grown during the whole growth process. During the growth of III-CNTs, the catalyst particles (Ni) stay on the tips of each of the aligned CNTs and act as a 'safety helmet' to protect the CNTs from plasma ion bombardment. On the other hand, it is also the plasma that limits the growth of III-CNTs, since the plasma eventually etches all the catalytic particles out and stops the growth. PMID:21911923

  18. The evolution of carbon nanotubes during their growth by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Wang, Hengzhi; Ren, Z. F.

    2011-10-01

    During the growth of carbon nanotubes (CNTs) by plasma enhanced chemical vapor deposition (PECVD), plasma etching is the crucial factor that determines the growth mode and alignment of the CNTs. Focusing on a thin catalyst coating (Ni = 5 nm), this study finds that the CNT growth by PECVD goes through three stages from randomly entangled (I-CNTs) to partially aligned (II-CNTs) to fully aligned (III-CNTs). The I-CNTs and II-CNTs are mostly etched away by the plasma as time goes by ending up with III-CNTs as the only product when growth time is long enough. However, with a thickness of the catalyst coating of 10 nm or more, neither I-CNTs nor II-CNTs are produced, but III-CNTs are the only type of CNTs grown during the whole growth process. During the growth of III-CNTs, the catalyst particles (Ni) stay on the tips of each of the aligned CNTs and act as a 'safety helmet' to protect the CNTs from plasma ion bombardment. On the other hand, it is also the plasma that limits the growth of III-CNTs, since the plasma eventually etches all the catalytic particles out and stops the growth.

  19. Enhanced cell adhesion to silicone implant material through plasma surface modification.

    PubMed

    Hauser, J; Zietlow, J; Köller, M; Esenwein, S A; Halfmann, H; Awakowicz, P; Steinau, H U

    2009-12-01

    Silicone implant material is widely used in the field of plastic surgery. Despite its benefits the lack of biocompatibility this material still represents a major problem. Due to the surface characteristics of silicone, protein adsorption and cell adhesion on this polymeric material is rather low. The aim of this study was to create a stable collagen I surface coating on silicone implants via glow-discharge plasma treatment in order to enhance cell affinity and biocompatibility of the material. Non-plasma treated, collagen coated and conventional silicone samples (non-plasma treated, non-coated) served as controls. After plasma treatment the change of surface free energy was evaluated by drop-shape analysis. The quality of the collagen coating was analysed by electron microscopy and Time-Of-Flight Secondary Ion Mass Spectrometry. For biocompatibility tests mouse fibroblasts 3T3 were cultivated on the different silicone surfaces and stained with calcein-AM and propidium iodine to evaluate cell viability and adherence. Analysis of the different surfaces revealed a significant increase in surface free energy after plasma pre-treatment. As a consequence, collagen coating could only be achieved on the plasma activated silicone samples. The in vitro tests showed that the collagen coating led to a significant increase in cell adhesion and cell viability. PMID:19641852

  20. Plasma etch characteristics of aluminum nitride mask layers grown by low-temperature plasma enhanced atomic layer deposition in SF{sub 6} based plasmas

    SciTech Connect

    Perros, Alexander; Bosund, Markus; Sajavaara, Timo; Laitinen, Mikko; Sainiemi, Lauri; Huhtio, Teppo; Lipsanen, Harri

    2012-01-15

    The plasma etch characteristics of aluminum nitride (AlN) deposited by low-temperature, 200 deg. C, plasma enhanced atomic layer deposition (PEALD) was investigated for reactive ion etch (RIE) and inductively coupled plasma-reactive ion etch (ICP-RIE) systems using various mixtures of SF{sub 6} and O{sub 2} under different etch conditions. During RIE, the film exhibits good mask properties with etch rates below 10r nm/min. For ICP-RIE processes, the film exhibits exceptionally low etch rates in the subnanometer region with lower platen power. The AlN film's removal occurred through physical mechanisms; consequently, rf power and chamber pressure were the most significant parameters in PEALD AlN film removal because the film was inert to the SF{sub x}{sup +} and O{sup +} chemistries. The etch experiments showed the film to be a resilient masking material. This makes it an attractive candidate for use as an etch mask in demanding SF{sub 6} based plasma etch applications, such as through-wafer etching, or when oxide films are not suitable.

  1. Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

    SciTech Connect

    Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, Yoon-Jae; Park, Man-Jin; Moon, Dae Won

    2012-02-15

    Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

  2. Remote Ischemic Preconditioning (RIPC) Modifies the Plasma Proteome in Children Undergoing Repair of Tetralogy of Fallot: A Randomized Controlled Trial

    PubMed Central

    Hepponstall, Michele; Ignjatovic, Vera; Binos, Steve; Attard, Chantal; Karlaftis, Vasiliki; d’Udekem, Yves; Monagle, Paul; Konstantinov, Igor E.

    2015-01-01

    Background Remote ischemic preconditioning (RIPC) has been applied in paediatric cardiac surgery. We have demonstrated that RIPC induces a proteomic response in plasma of healthy volunteers. We tested the hypothesis that RIPC modifies the proteomic response in children undergoing Tetralogy of Fallot (TOF) repair. Methods and Results Children (n=40) were randomized to RIPC and control groups. Blood was sampled at baseline, after cardiopulmonary bypass (CPB) and 6, 12 and 24h post-CPB. Plasma was analysed by liquid chromatography mass spectrometry (LC-MS) in an untargeted approach. Peptides demonstrating differential expression (p<0.01) were subjected to tandem LC-MS/MS and protein identification. Corresponding proteins were identified using the NCBI protein database. There was no difference in age (7.3±3.5vs6.8±3.6 months)(p=0.89), weight (7.7±1.8vs7.5±1.9 kg)(p=0.71), CPB time (104±7vs94±7 min)(p=0.98) or aortic cross-clamp time (83±22vs75±20 min)(p=0.36). No peptides were differentially expressed at baseline or immediately after CPB. There were 48 peptides with higher expression in the RIPC group 6h post-CPB. This was no longer evident at 12 or 24h, with one peptide down-regulated in the RIPC group. The proteins identified were: inter-alpha globulin inhibitor (42.0±11.8 vs 820.8±181.1, p=0.006), fibrinogen preproprotein (59.3±11.2 vs 1192.6±278.3, p=0.007), complement-C3 precursor (391.2±160.9 vs 5385.1±689.4, p=0.0005), complement C4B (151.5±17.8 vs 4587.8±799.2, p=0.003), apolipoprotein B100 (53.4±8.3 vs 1364.5±278.2, p=0.005) and urinary proteinase inhibitor (358.6±74.9 vs 5758.1±1343.1, p=0.009). These proteins are involved in metabolism, haemostasis, immunity and inflammation. Conclusions We provided the first comprehensive analysis of RIPC-induced proteomic changes in children undergoing surgery. The proteomic changes peak 6h post-CPB and return to baseline within 24h of surgery. Trial Registration ACTR.org.au ACTRN12610000496011 PMID

  3. Improved film quality of plasma enhanced atomic layer deposition SiO{sub 2} using plasma treatment cycle

    SciTech Connect

    Kim, Haiwon; Chung, Ilsub; Kim, Seokyun; Shin, Seungwoo; Jung, Wooduck; Hwang, Ryong; Jeong, Choonsik; Hwang, Hanna

    2015-01-15

    Chemical, physical, and electrical characteristics of high quality silicon dioxide (SiO{sub 2}) films grown using low temperature plasma enhanced atomic layer deposition (PE-ALD) have been investigated as a buffer layer for three dimensional vertical NAND flash memory devices. The comparative angle resolved x-ray photoelectron spectroscopy studies show the plasma treatment cycle causes to shift the core level binding energy (chemical shifts) in the SiO{sub 2} film. The wet etch rates with respect to plasma treatment cycle times were varied due to curing of the SiO{sub 2} network defects by Ar{sup +} ions and oxygen radicals. It is assumed that the angle between the bonds linking SiO{sub 4} tetrahedra is a critical point understanding the variation in wet etch rate of SiO{sub 2}. The features of wet etch rate of low temperature high quality SiO{sub 2} demonstrated lower than high temperature low-pressure chemical vapor deposition (LP-CVD) SiO{sub 2} values. In addition, the better step-coverage compared to that of the LP-CVD SiO{sub 2} film was achieved from the deep trench structure having the 20:1 aspect ratio. PE-ALD SiO{sub 2} with plasma treatment cycle showed excellent I–V properties with higher breakdown voltage compared to LP-CVD SiO{sub 2} and similar to the thermal SiO{sub 2} carrier transport plot.

  4. Surface cleaning for enhanced adhesion to packaging surfaces: Effect of oxygen and ammonia plasma

    SciTech Connect

    Gaddam, Sneha; Dong, Bin; Driver, Marcus; Kelber, Jeffry; Kazi, Haseeb

    2015-03-15

    The effects of direct plasma chemistries on carbon removal from silicon nitride (SiN{sub x}) and oxynitride (SiO{sub x}N{sub y}) surfaces have been studied by in-situ x-ray photoelectron spectroscopy (XPS) and ex-situ contact angle measurements. The data indicate that O{sub 2} and NH{sub 3} capacitively coupled plasmas are effective at removing adventitious carbon from silicon nitride (SiN{sub x}) and Si oxynitride (SiO{sub x}N{sub y}) surfaces. O{sub 2} plasma treatment results in the formation of a silica overlayer. In contrast, the exposure to NH{sub 3} plasma results in negligible additional oxidation of the SiN{sub x} or SiO{sub x}N{sub y} surface. Ex-situ contact angle measurements show that SiN{sub x} and SiO{sub x}N{sub y} surfaces exposed to oxygen plasma are initially more hydrophilic than surfaces exposed to NH{sub 3} plasma, indicating that the O{sub 2} plasma-induced SiO{sub 2} overlayer is highly reactive toward ambient. At longer ambient exposures (≳10 h), however, surfaces treated by either O{sub 2} or NH{sub 3} plasma exhibit similar steady state contact angles, correlated with rapid uptake of adventitious carbon, as determined by XPS. Surface passivation by exposure to molecular hydrogen prior to ambient exposure significantly retards the increase in contact angle upon exposure to ambient. The results suggest a practical route to enhancing the time available for effective bonding to surfaces in microelectronics packaging applications.

  5. Enhanced algorithm performance for land cover classification from remotely sensed data using bagging and boosting

    USGS Publications Warehouse

    Chan, J.C.-W.; Huang, C.; DeFries, R.

    2001-01-01

    Two ensemble methods, bagging and boosting, were investigated for improving algorithm performance. Our results confirmed the theoretical explanation [1] that bagging improves unstable, but not stable, learning algorithms. While boosting enhanced accuracy of a weak learner, its behavior is subject to the characteristics of each learning algorithm.

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

    NASA Astrophysics Data System (ADS)

    Fan, Liwei; Zhang, Hui; Zhang, Pingping; Sun, Xuhui

    2015-08-01

    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 CuCl2 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.

  7. RF plasma enhanced MOCVD of yttria stabilized zirconia thin films using octanedionate precursors and their characterization

    NASA Astrophysics Data System (ADS)

    Chopade, S. S.; Nayak, C.; Bhattacharyya, D.; Jha, S. N.; Tokas, R. B.; Sahoo, N. K.; Deo, M. N.; Biswas, A.; Rai, Sanjay; Thulasi Raman, K. H.; Rao, G. M.; Kumar, Niranjan; Patil, D. S.

    2015-11-01

    Yttria stabilized zirconia thin films have been deposited by RF plasma enhanced MOCVD technique on silicon substrates at substrate temperature of 400 °C. Plasma of precursor vapors of (2,7,7-trimethyl-3,5-octanedionate) yttrium (known as Y(tod)3), (2,7,7-trimethyl-3,5-octanedionate) zirconium (known as Zr(tod)4), oxygen and argon gases is used for deposition. To the best of our knowledge, plasma assisted MOCVD of YSZ films using octanediaonate precursors have not been reported in the literature so far. The deposited films have been characterized by GIXRD, FTIR, XPS, FESEM, AFM, XANES, EXAFS, EDAX and spectroscopic ellipsometry. Thickness of the films has been measured by stylus profilometer while tribological property measurement has been done to study mechanical behavior of the coatings. Characterization by different techniques indicates that properties of the films are dependent on the yttria content as well as on the structure of the films.

  8. Instability-Enhanced Collisional Friction Can Determine the Bohm Criterion in Multiple-Ion-Species Plasmas

    SciTech Connect

    Baalrud, S. D.; Hegna, C. C.; Callen, J. D.

    2009-11-13

    A generalized Lenard-Balescu theory that accounts for instability-enhanced collective responses is used to calculate the collisional friction between ion species in the plasma-boundary transition region (presheath). Ion-ion streaming instabilities are shown to cause such a strong frictional force that the relative flow speed between ion species cannot significantly exceed the critical threshold value (DELTAV{sub c}) at which instability onset occurs. When combined with the Bohm criterion, this condition uniquely determines the flow speed of each ion species at the plasma-sheath boundary. For cold ions, DELTAV{sub c}->0 and each ion species leaves the plasma at a common system sound speed c{sub s}.

  9. Instability-enhanced collisional friction can determine the Bohm criterion in multiple-ion-species plasmas.

    PubMed

    Baalrud, S D; Hegna, C C; Callen, J D

    2009-11-13

    A generalized Lenard-Balescu theory that accounts for instability-enhanced collective responses is used to calculate the collisional friction between ion species in the plasma-boundary transition region (presheath). Ion-ion streaming instabilities are shown to cause such a strong frictional force that the relative flow speed between ion species cannot significantly exceed the critical threshold value (DeltaV(c)) at which instability onset occurs. When combined with the Bohm criterion, this condition uniquely determines the flow speed of each ion species at the plasma-sheath boundary. For cold ions, DeltaV(c) --> 0 and each ion species leaves the plasma at a common system sound speed c(s). PMID:20365986

  10. Plasma-enhanced chemical vapor deposition of amorphous Si on graphene

    NASA Astrophysics Data System (ADS)

    Lupina, G.; Strobel, C.; Dabrowski, J.; Lippert, G.; Kitzmann, J.; Krause, H. M.; Wenger, Ch.; Lukosius, M.; Wolff, A.; Albert, M.; Bartha, J. W.

    2016-05-01

    Plasma-enhanced chemical vapor deposition of thin a-Si:H layers on transferred large area graphene is investigated. Radio frequency (RF, 13.56 MHz) and very high frequency (VHF, 140 MHz) plasma processes are compared. Both methods provide conformal coating of graphene with Si layers as thin as 20 nm without any additional seed layer. The RF plasma process results in amorphization of the graphene layer. In contrast, the VHF process keeps the high crystalline quality of the graphene layer almost intact. Correlation analysis of Raman 2D and G band positions indicates that Si deposition induces reduction of the initial doping in graphene and an increase of compressive strain. Upon rapid thermal annealing, the amorphous Si layer undergoes dehydrogenation and transformation into a polycrystalline film, whereby a high crystalline quality of graphene is preserved.