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Sample records for liquid injection mocvd

  1. Cobalt (II) β-diketonate adducts as new precursors for the growth of cobalt oxide films by liquid injection MOCVD

    NASA Astrophysics Data System (ADS)

    Pasko, S.; Abrutis, A.; Hubert-Pfalzgraf, L. G.; Kubilius, V.

    2004-02-01

    New metalorganic compounds—adducts of cobalt(II) acetylacetonate (acac) and cobalt(II) 2,2,6,6-tetramethyl-3,5-heptanedionate (thd) with N,N,N',N'-tetramethyl-1,2-diaminoethane have been synthesized and studied as potential precursors for liquid injection metalorganic chemical vapor deposition of Co 3O 4 films. The properties of the films were compared with those deposited using standard [Co(acac) 2] 4 and Co(thd) 2 precursors. Depositions were carried out at 350-600°C on LaAlO 3 (1 0 0), sapphire (R-plane), MgO (1 0 0) and Si (1 0 0) substrates. The films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. Depending on substrate material, highly (1 1 0) or (1 0 0) textured Co 3O 4 films have been deposited; moreover, films exhibited preferential in-plane orientation. No significant difference has been found in the quality of Co 3O 4 films deposited from different precursors.

  2. Thin YBCO films on ? (001) substrates grown by injection MOCVD

    NASA Astrophysics Data System (ADS)

    Abrutis, A.; Sénateur, J. P.; Weiss, F.; Kubilius, V.; Bigelyte, V.; Saltyte, Z.; Vengalis, B.; Jukna, A.

    1997-12-01

    YBCO thin (about 0953-2048/10/12/021/img10) films were deposited at 0953-2048/10/12/021/img11 on 0953-2048/10/12/021/img12 (001) by single-source injection CVD. Precisely controlled microamounts of organometallic 0953-2048/10/12/021/img13-diketonates dissolved in an organic solvent were injected sequentially into the evaporator by means of a computer-driven injector and the resultant vapour was transported into the deposition zone. The influence of the vapour phase composition on films' properties was investigated. A mixture of 0953-2048/10/12/021/img14 and 0953-2048/10/12/021/img15-oriented YBCO crystallites exists in all deposited films and its ratio depends on the vapour phase composition. For both a and c perpendicular crystallites only 0953-2048/10/12/021/img16 in-plane orientation with respect to substrate axes was found. Bidirectional twinning was established in the crystallites of both types. 0953-2048/10/12/021/img17 of the films (about 90 K) was almost independent of the vapour phase composition in the studied range. However, the critical current density 0953-2048/10/12/021/img18 depended clearly on the vapour phase composition in relation to the 0953-2048/10/12/021/img19 ratio variation. 0953-2048/10/12/021/img18 of the films varied in the range 0953-2048/10/12/021/img21.

  3. Portable Liquid-Injecting System

    NASA Technical Reports Server (NTRS)

    Shuck, T.; Chin, F.; Hansen, M.

    1988-01-01

    Portable injecting-gun system dispenses predetermined amount of liquid at moderately high pressure. Tool belt holds components of liquid-injecting system. Pump and four-way valve combined in nylon housing. Connected to injecting nozzle and other components by polyvinyl tubing.

  4. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, P.C.; Watkins, A.D.

    1999-05-25

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube. 8 figs.

  5. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, Peter C.; Watkins, Arthur D.

    1999-01-01

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube.

  6. The quest towards epitaxial BaMgF4 thin films: exploring MOCVD as a chemical scalable approach for the deposition of complex metal fluoride films.

    PubMed

    Battiato, Sergio; Deschanvres, Jean-Luc; Roussel, Hervé; Rapenne, Laetitia; Doisneau, Béatrice; Condorelli, Guglielmo G; Muñoz-Rojas, David; Jiménez, Carmen; Malandrino, Graziella

    2016-11-28

    Conventional and Pulsed Liquid Injection MOCVD processes (C-MOCVD and PLI-MOCVD) have been explored as synthetic routes for the growth of BaMgF4 on Si (100) and single crystalline SrTiO3 (100) substrates. For the two applied approaches, the volatile, thermally stable β-diketonate complexes Ba(hfa)2tetraglyme and Mg(hfa)2(diglyme)2(H2O)2 have been used as single precursors (C-MOCVD) or as a solution multimetal source (PLI-MOCVD). Structural characterization through X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) analyses confirmed the formation of epitaxial BaMgF4 films on SrTiO3 substrates. Energy dispersive X-ray (EDX) analyses have been used to confirm composition and purity of deposited films. The impact of process parameters on film properties has been addressed, highlighting the strong influence of precursor ratio, deposition temperature and oxygen partial pressure on composition, microstructure and morphology of the films. Both methods appear well suited for the growth of the BaMgF4 phase, but while PLI-MOCVD yields a more straightforward control of the precursor composition that reflects on film stoichiometry, C-MOCVD provides easier control of the degree of texturing as a function of temperature.

  7. Liquid injectable silicone for soft tissue augmentation.

    PubMed

    Prather, Chad L; Jones, Derek H

    2006-01-01

    Liquid injectable silicone is a unique soft tissue augmenting agent that may be effectively utilized for the correction of specific cutaneous and subcutaneous atrophies. Although historical complications have occurred, resulting likely from the presence of adulterants and impurities, modern purified silicone products approved by the Food and Drug Administration for injection into the human body may be employed with minimal complications when strict protocol is followed. In this article the present authors review the history and controversy regarding silicone as well as describe the appropriate indications, patient selection, instrumentation, treatment protocol, and anticipated complications involved with the use of liquid injectable silicone for soft tissue augmentation. Although its use is controversial, the present authors maintain that liquid injectable silicone is an important and effective augmenting agent for the long-term correction of scars and facial contour defects such as HIV facial lipoatrophy. Furthermore, it is a treatment modality deserving of continued investigation.

  8. [Development of a novel liquid injection system].

    PubMed

    Chen, Kai; Lv, Yong-Gui

    2009-11-01

    A liquid jet injector employs compressed gas or spring to produce a high-velocity stream to deliver liquid drug into human body through skin. There are many clinical jet injection products available, none of which is domestic. A new liquid jet injector is designed based on a comprehensive analysis of the current products. The injector consists of an ejector, trigger and a re-positioning mechanism. The jets characteristics of sample injector are tested, and the results show that the maximum exit pressure is above 15 MPa, a threshold value for penetrating into the skin.

  9. Liquid fuel injection elements for rocket engines

    NASA Technical Reports Server (NTRS)

    Cox, George B., Jr. (Inventor)

    1993-01-01

    Thrust chambers for liquid propellant rocket engines include three principal components. One of these components is an injector which contains a plurality of injection elements to meter the flow of propellants at a predetermined rate, and fuel to oxidizer mixture ratio, to introduce the mixture into the combustion chamber, and to cause them to be atomized within the combustion chamber so that even combustion takes place. Evolving from these injectors are tube injectors. These tube injectors have injection elements for injecting the oxidizer into the combustion chamber. The oxidizer and fuel must be metered at predetermined rates and mixture ratios in order to mix them within the combustion chamber so that combustion takes place smoothly and completely. Hence tube injectors are subject to improvement. An injection element for a liquid propellant rocket engine of the bipropellant type is provided which includes tangential fuel metering orifices, and a plurality of oxidizer tube injection elements whose injection tubes are also provided with tangential oxidizer entry slots and internal reed valves.

  10. Spin-polarized quasiparticle injection effect in MOCVD-grown YBa 2Cu 3O 7/SrTiO 3/La 1- xSr xMnO 3 heterostructures

    NASA Astrophysics Data System (ADS)

    Plausinaitiene, V.; Abrutis, A.; Vengalis, B.; Butkute, R.; Senateur, J. P.; Saltyte, Z.; Kubilius, V.

    2001-03-01

    Metal oxide heterostructures consisting of the ferromagnetic La 1- xSr xMnO 3 ( x≈0.3) underlayer, thin ( d≅5-10 nm) SrTiO 3 barrier layer and YBa 2Cu 3O 7 cap layer were grown on single crystal LaAlO 3 (1 0 0) substrates at 825°C under oxygen pressure of about 200 Pa by single source pulsed injection MOCVD method. The technological conditions were optimized in order to improve crystallinity and surface quality of the constituent layers. Wet etching was applied to form tape-like superconducting films for investigation of both longitudinal and transverse electrical transport in the heterostructures. Significant suppression of supercurrent has been found by injecting tunneling spin-polarized current from the underlying FM layer.

  11. Pulsed liquid microjet for intravascular injection

    NASA Astrophysics Data System (ADS)

    Palanker, Daniel V.; Fletcher, Daniel A.; Miller, Jason; Huie, Philip; Marmor, Michael; Blumenkranz, Mark S.

    2002-06-01

    Occlusions of the retinal veins and arteries are associated with common diseases such as hypertension and arteriosclerosis and usually cause severe and irreversible loss of vision. Treatments for these vascular diseases have been unsatisfactory to date in part because of the difficulty of delivering thrombolytic drugs locally within the eye. In this article we describe a pulsed liquid microjet for minimally invasive intra-vascular drug delivery. The microjet is driven by a vapor bubble following an explosive evaporation of saline, produced by a microsecond-long electric discharge in front of the 25 micrometers electrode inside the micronozzle. Expansion of the transient vapor bubble produces a water jet with a diameter equal to the diameter of the nozzle, and with a velocity and duration that are controlled by the pulse energy. We found that fluid could be injected through the wall of a 60-micrometers -diameter artery in choriallantoic membrane using a 15-micrometers diameter liquid jet traveling at more than 60 m/s. Histological analysis of these arteries showed that the width of the perforation is limited to the diameter of the micronozzle, and the penetration depth of the jet is controlled by the discharge energy. The pulsed liquid microjet offers a promising technique for precise and needle-free intravascular delivery of thrombolytic drugs for localized treatment of retinal vascular occlusions.

  12. Extinction of solid rocket motor by liquid injection

    NASA Astrophysics Data System (ADS)

    Yin, Jinqi; Li, Baoxiun; Wang, Kexiu; Wu, Xinping; Zhang, Baoqing; Su, Guangshou

    1992-10-01

    An empirical data-based theoretical model is presented for liquid quenching of a solid rocket motor, taking into account the details of internal-ballistics coupling effects, solid propellant transient burning, liquid drop evaporation, and heat transfer via liquid-jet boiling. The exceeding of a critical injection pressure drop value is found to be required for effective quenching; as the injection pressure drop increases, the volume of the liquid required for reliable extinction decreases. Good agreement with experimental results is obtained.

  13. Solid source MOCVD system

    DOEpatents

    Hubert, Brian N.; Wu, Xin Di

    1998-01-01

    A system for MOCVD fabrication of superconducting and non-superconducting oxide films provides a delivery system for the feeding of metalorganic precursors for multi-component chemical vapor deposition. The delivery system can include multiple cartridges containing tightly packed precursor materials. The contents of each cartridge can be ground at a desired rate and fed together with precursor materials from other cartridges to a vaporization zone and then to a reaction zone within a deposition chamber for thin film deposition.

  14. Solid source MOCVD system

    DOEpatents

    Hubert, B.N.; Wu, X.D.

    1998-10-13

    A system for MOCVD fabrication of superconducting and non-superconducting oxide films provides a delivery system for the feeding of metallorganic precursors for multi-component chemical vapor deposition. The delivery system can include multiple cartridges containing tightly packed precursor materials. The contents of each cartridge can be ground at a desired rate and fed together with precursor materials from other cartridges to a vaporization zone and then to a reaction zone within a deposition chamber for thin film deposition. 13 figs.

  15. OBSERVATIONS ON WASTE DESTRUCTION IN LIQUID INJECTION INCINERATORS

    EPA Science Inventory

    Various factors affecting the performance of a subscale liquid injection incinerator simulator are discussed. The mechanisms by which waste escapes incineration within the spray flame are investigated for variations in atomization quality, flame stoichiometry. and the initial was...

  16. Supersonic Injection of Aerated Liquid Jet

    NASA Astrophysics Data System (ADS)

    Choudhari, Abhijit; Sallam, Khaled

    2016-11-01

    A computational study of the exit flow of an aerated two-dimensional jet from an under-expanded supersonic nozzle is presented. The liquid sheet is operating within the annular flow regime and the study is motivated by the application of supersonic nozzles in air-breathing propulsion systems, e.g. scramjet engines, ramjet engines and afterburners. The simulation was conducted using VOF model and SST k- ω turbulence model. The test conditions included: jet exit of 1 mm and mass flow rate of 1.8 kg/s. The results show that air reaches transonic condition at the injector exit due to the Fanno flow effects in the injector passage. The aerated liquid jet is alternately expanded by Prandtl-Meyer expansion fan and compressed by oblique shock waves due to the difference between the back (chamber) pressure and the flow pressure. The process then repeats itself and shock (Mach) diamonds are formed at downstream of injector exit similar to those typical of exhaust plumes of propulsion system. The present results, however, indicate that the flow field of supersonic aerated liquid jet is different from supersonic gas jets due to the effects of water evaporation from the liquid sheet. The contours of the Mach number, static pressure of both cases are compared to the theory of gas dynamics.

  17. Multiplexed electrospray scaling for liquid fuel injection

    NASA Astrophysics Data System (ADS)

    Waits, C. Mike; Hanrahan, Brendan; Lee, Ivan

    2010-10-01

    Evaporation and space-charge requirements are evaluated to understand the effect of device scaling and fuel preheating for a liquid fuel injector using a multiplexed electrospray (MES) configuration in compact combustion applications. This work reveals the influence of the droplet diameter, droplet velocity and droplet surface temperature as well as the surrounding gas temperature on the size and performance of microfabricated MES. Measurements from MES devices are used in the model to accurately account for the droplet diameter versus flow rate relationship, the minimum droplet diameter and the relevant droplet velocities. A maximum extractor electrode to ground electrode distance of 3.1 mm required to overcome space-charge forces is found to be independent of voltage or droplet velocity for large levels of multiplexing. This maximum distance also becomes the required evaporation length scale which imposes minimum fuel pre-heating requirements for large flow densities. Required fuel preheating is therefore evaluated for both ethanol and 1-butanol with combustor parameters relevant to fuel reformation, thermoelectric conversion, thermophotovoltaic conversion and thermionic conversion.

  18. Vacuum MOCVD fabrication of high efficience cells

    NASA Technical Reports Server (NTRS)

    Partain, L. D.; Fraas, L. M.; Mcleod, P. S.; Cape, J. A.

    1985-01-01

    Vacuum metal-organic-chemical-vapor-deposition (MOCVD) is a new fabrication process with improved safety and easier scalability due to its metal rather than glass construction and its uniform multiport gas injection system. It uses source materials more efficiently than other methods because the vacuum molecular flow conditions allow the high sticking coefficient reactants to reach the substrates as undeflected molecular beams and the hot chamber walls cause the low sticking coefficient reactants to bounce off the walls and interact with the substrates many times. This high source utilization reduces the materials costs power device and substantially decreases the amounts of toxic materials that must be handled as process effluents. The molecular beams allow precise growth control. With improved source purifications, vacuum MOCVD has provided p GaAs layers with 10-micron minority carrier diffusion lengths and GaAs and GaAsSb solar cells with 20% AMO efficiencies at 59X and 99X sunlight concentration ratios. Mechanical stacking has been identified as the quickest, most direct and logical path to stacked multiple-junction solar cells that perform better than the best single-junction devices. The mechanical stack is configured for immediate use in solar arrays and allows interconnections that improve the system end-of-life performance in space.

  19. Wideband-Switchable Metamaterial Absorber Using Injected Liquid Metal

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Ki; Lee, Dongju; Lim, Sungjoon

    2016-08-01

    Metamaterial absorbers can provide good solutions for radar-cross-section (RCS) reduction. In spite of their attractive features of thinness, lightness, and low cost, resonant metamaterial absorbers have a drawback of narrow bandwidth. For practical radar applications, wideband absorbers are necessary. In this paper, we propose a wideband-switchable metamaterial absorber using liquid metal. In order to reduce RCS both for X-band and C-band, the switchable Jerusalem cross (JC) resonator is introduced. The JC resonator consists of slotted circular rings, chip resistors, and microfluidic channels. The JC resonator is etched on a flexible printed circuit board (FPCB), and the microfluidic channels are laser-etched on a polydimethylsiloxane (PDMS) material. The proposed absorber can switch the absorption frequency band by injecting a liquid metal alloy into the channels. The performance of the absorber was demonstrated through full-wave simulation and through measurements employing prototypes. The experimental results showed absorption ratios of over 90% from 7.43 GHz to 14.34 GHz, and from 5.62 GHz to 7.3 GHz, with empty channels and liquid metal-filled channels, respectively. Therefore, the absorption band was successfully switched between the C-band (4–8 GHz) and the X-band (8–12 GHz) by injecting liquid metal eutectic gallium indium alloy (EGaIn) into the channels.

  20. Wideband-Switchable Metamaterial Absorber Using Injected Liquid Metal.

    PubMed

    Kim, Hyung Ki; Lee, Dongju; Lim, Sungjoon

    2016-08-22

    Metamaterial absorbers can provide good solutions for radar-cross-section (RCS) reduction. In spite of their attractive features of thinness, lightness, and low cost, resonant metamaterial absorbers have a drawback of narrow bandwidth. For practical radar applications, wideband absorbers are necessary. In this paper, we propose a wideband-switchable metamaterial absorber using liquid metal. In order to reduce RCS both for X-band and C-band, the switchable Jerusalem cross (JC) resonator is introduced. The JC resonator consists of slotted circular rings, chip resistors, and microfluidic channels. The JC resonator is etched on a flexible printed circuit board (FPCB), and the microfluidic channels are laser-etched on a polydimethylsiloxane (PDMS) material. The proposed absorber can switch the absorption frequency band by injecting a liquid metal alloy into the channels. The performance of the absorber was demonstrated through full-wave simulation and through measurements employing prototypes. The experimental results showed absorption ratios of over 90% from 7.43 GHz to 14.34 GHz, and from 5.62 GHz to 7.3 GHz, with empty channels and liquid metal-filled channels, respectively. Therefore, the absorption band was successfully switched between the C-band (4-8 GHz) and the X-band (8-12 GHz) by injecting liquid metal eutectic gallium indium alloy (EGaIn) into the channels.

  1. Wideband-Switchable Metamaterial Absorber Using Injected Liquid Metal

    PubMed Central

    Kim, Hyung Ki; Lee, Dongju; Lim, Sungjoon

    2016-01-01

    Metamaterial absorbers can provide good solutions for radar-cross-section (RCS) reduction. In spite of their attractive features of thinness, lightness, and low cost, resonant metamaterial absorbers have a drawback of narrow bandwidth. For practical radar applications, wideband absorbers are necessary. In this paper, we propose a wideband-switchable metamaterial absorber using liquid metal. In order to reduce RCS both for X-band and C-band, the switchable Jerusalem cross (JC) resonator is introduced. The JC resonator consists of slotted circular rings, chip resistors, and microfluidic channels. The JC resonator is etched on a flexible printed circuit board (FPCB), and the microfluidic channels are laser-etched on a polydimethylsiloxane (PDMS) material. The proposed absorber can switch the absorption frequency band by injecting a liquid metal alloy into the channels. The performance of the absorber was demonstrated through full-wave simulation and through measurements employing prototypes. The experimental results showed absorption ratios of over 90% from 7.43 GHz to 14.34 GHz, and from 5.62 GHz to 7.3 GHz, with empty channels and liquid metal-filled channels, respectively. Therefore, the absorption band was successfully switched between the C-band (4–8 GHz) and the X-band (8–12 GHz) by injecting liquid metal eutectic gallium indium alloy (EGaIn) into the channels. PMID:27546310

  2. Superheated fuel injection for combustion of liquid-solid slurries

    DOEpatents

    Robben, Franklin A.

    1985-01-01

    A method and device for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal.

  3. Superheated fuel injection for combustion of liquid-solid slurries

    DOEpatents

    Robben, F.A.

    1984-10-19

    A method and device are claimed for obtaining, upon injection, flash evaporation of a liquid in a slurry fuel to aid in ignition and combustion. The device is particularly beneficial for use of coal-water slurry fuels in internal combustion engines such as diesel engines and gas turbines, and in external combustion devices such as boilers and furnaces. The slurry fuel is heated under pressure to near critical temperature in an injector accumulator, where the pressure is sufficiently high to prevent boiling. After injection into a combustion chamber, the water temperature will be well above boiling point at a reduced pressure in the combustion chamber, and flash boiling will preferentially take place at solid-liquid surfaces, resulting in the shattering of water droplets and the subsequent separation of the water from coal particles. This prevents the agglomeration of the coal particles during the subsequent ignition and combustion process, and reduces the energy required to evaporate the water and to heat the coal particles to ignition temperature. The overall effect will be to accelerate the ignition and combustion rates, and to reduce the size of the ash particles formed from the coal. 2 figs., 2 tabs.

  4. Jet-noise reduction through liquid-base foam injection.

    NASA Technical Reports Server (NTRS)

    Manson, L.; Burge, H. L.

    1971-01-01

    An experimental investigation has been made of the sound-absorbing properties of liquid-base foams and of their ability to reduce jet noise. Protein, detergent, and polymer foaming agents were used in water solutions. A method of foam generation was developed to permit systematic variation of the foam density. The investigation included measurements of sound-absorption coefficents for both plane normal incidence waves and diffuse sound fields. The intrinsic acoustic properties of foam, e.g., the characteristic impedance and the propagation constant, were also determined. The sound emitted by a 1-in.-diam cold nitrogen jet was measured for subsonic (300 m/sec) and supersonic (422 m/sec) jets, with and without foam injection. Noise reductions up to 10 PNdB were measured.

  5. Refrigeration system with a compressor-pump unit and a liquid-injection desuperheating line

    DOEpatents

    Gaul, Christopher J.

    2001-01-01

    The refrigeration system includes a compressor-pump unit and/or a liquid-injection assembly. The refrigeration system is a vapor-compression refrigeration system that includes an expansion device, an evaporator, a compressor, a condenser, and a liquid pump between the condenser and the expansion device. The liquid pump improves efficiency of the refrigeration system by increasing the pressure of, thus subcooling, the liquid refrigerant delivered from the condenser to the expansion device. The liquid pump and the compressor are driven by a single driving device and, in this regard, are coupled to a single shaft of a driving device, such as a belt-drive, an engine, or an electric motor. While the driving device may be separately contained, in a preferred embodiment, the liquid pump, the compressor, and the driving device (i.e., an electric motor) are contained within a single sealable housing having pump and driving device cooling paths to subcool liquid refrigerant discharged from the liquid pump and to control the operating temperature of the driving device. In another aspect of the present invention, a liquid injection assembly is included in a refrigeration system to divert liquid refrigerant from the discharge of a liquid pressure amplification pump to a compressor discharge pathway within a compressor housing to desuperheat refrigerant vapor to the saturation point within the compressor housing. The liquid injection assembly includes a liquid injection pipe with a control valve to meter the volume of diverted liquid refrigerant. The liquid injection assembly may also include a feedback controller with a microprocessor responsive to a pressure sensor and a temperature sensor both positioned between the compressor to operate the control valve to maintain the refrigerant at or near saturation.

  6. Experimental characterization and modeling for the growth rate of oxide coatings from liquid solutions of metalorganic precursors by ultrasonic pulsed injection in a cold-wall low-pressure reactor

    NASA Astrophysics Data System (ADS)

    Krumdieck, Susan Pran

    Several years ago, a method for depositing ceramic coatings called the Pulsed-MOCVD system was developed by the Raj group at Cornell University in association with Dr. Harvey Berger and Sono-Tek Corporation. The process was used to produce epitaxial thin films of TiO2 on sapphire substrates under conditions of low pressure, relatively high temperature, and very low growth rate. The system came to CU-Boulder when Professor Raj moved here in 1997. It is quite a simple technique and has several advantages over typical CVD systems. The purpose of this dissertation is two-fold; (1) understand the chemical processes, thermodynamics, and kinetics of the Pulsed-MOCVD technique, and (2) determine the possible applications by studying the film structure and morphology over the entire range of deposition conditions. Polycrystalline coatings of ceramic materials were deposited on nickel in the low-pressure, cold-wall reactor from metalorganic precursors, titanium isopropoxide, and a mixture of zirconium isopropoxide and yttria isopropoxide. The process utilized pulsed liquid injection of a dilute precursor solution with atomization by ultrasonic nozzle. Thin films (less than 1mum) with fine-grained microstructure and thick coatings (up to 1mum) with columnar-microstructure were deposited on heated metal substrates by thermal decomposition of a single liquid precursor. The influence of each of the primary deposition parameters, substrate temperature, total flow rate, and precursor concentration on growth rate, conversion efficiency and morphology were investigated. The operating conditions were determined for kinetic, mass transfer, and evaporation process control regimes. Kinetic controlled deposition was found to produce equiaxed morphology while mass transfer controlled deposition produced columnar morphology. A kinetic model of the deposition process was developed and compared to data for deposition of TiO2 from Ti(OC3H7) 4 precursor. The results demonstrate that growth

  7. Bubble formation during horizontal gas injection into downward-flowing liquid

    NASA Astrophysics Data System (ADS)

    Bai, Hua; Thomas, Brian G.

    2001-12-01

    Bubble formation during gas injection into turbulent downward-flowing water is studied using high-speed videos and mathematical models. The bubble size is determined during the initial stages of injection and is very important to turbulent multiphase flow in molten-metal processes. The effects of liquid velocity, gas-injection flow rate, injection hole diameter, and gas composition on the initial bubble-formation behavior have been investigated. Specifically, the bubble-shape evolution, contact angles, size, size range, and formation mode are measured. The bubble size is found to increase with increasing gas-injection flow rate and decreasing liquid velocity and is relatively independent of the gas injection hole size and gas composition. Bubble formation occurs in one of four different modes, depending on the liquid velocity and gas flow rate. Uniform-sized spherical bubbles form and detach from the gas injection hole in mode I for a low liquid speed and small gas flow rate. Modes III and IV occur for high-velocity liquid flows, where the injected gas elongates down along the wall and breaks up into uneven-sized bubbles. An analytical two-stage model is developed to predict the average bubble size, based on realistic force balances, and shows good agreement with measurements. Preliminary results of numerical simulations of bubble formation using a volume-of-fluid (VOF) model qualitatively match experimental observations, but more work is needed to reach a quantitative match. The analytical model is then used to estimate the size of the argon bubbles expected in liquid steel in tundish nozzles for conditions typical of continuous casting with a slide gate. The average argon bubble sizes generated in liquid steel are predicted to be larger than air bubbles in water for the same flow conditions. However, the differences lessen with increasing liquid velocity.

  8. Subsurface injection of liquid waste in Florida, United States of America

    USGS Publications Warehouse

    Vecchioli, John

    1981-01-01

    In 1979, liquid waste was injected into the subsurface of Florida by 10 injection systems at an aggregate average rate of 165,000 m3/d. All the systems inject into carbonate rocks that contain salty water. Extensive precautions are taken in the construction of the injection wells and in the monitoring of their operation to provide assurance that overlying and laterally contiguous freshwater resources do not become contaminated with either the injected waste or the saltwater displaced by the waste. Several concerns relating to the effectiveness of the confining bed above the injection zone for containing the injected wastes have arisen over the years. These concerns accentuate the value of a well-planned and implemented monitoring program from which one can evaluate the potential impact of waste injection on the subsurface environment.

  9. Monitoring of MOCVD reactants by UV absorption

    SciTech Connect

    Baucom, K.C.; Killeen, K.P.; Moffat, H.K.

    1995-07-01

    In this paper, we describe how UV absorption measurements can be used to measure the flow rates of metal organic chemical vapor deposition (MOCVD) reactants. This method utilizes the calculation of UV extinction coefficients by measuring the total pressure and absorbance in the neat reactant system. The development of this quantitative reactant flow rate monitor allows for the direct measurement of the efficiency of a reactant bubbler. We demonstrate bubbler efficiency results for TMGa, and then explain some discrepancies found in the TMAl system due to the monomer to dimer equilibrium. Also, the UV absorption spectra of metal organic and hydride MOCVD reactants over the wavelength range 185 to 400 nm are reported.

  10. Frequency-Switchable Metamaterial Absorber Injecting Eutectic Gallium-Indium (EGaIn) Liquid Metal Alloy.

    PubMed

    Ling, Kenyu; Kim, Hyung Ki; Yoo, Minyeong; Lim, Sungjoon

    2015-11-06

    In this study, we demonstrated a new class of frequency-switchable metamaterial absorber in the X-band. Eutectic gallium-indium (EGaIn), a liquid metal alloy, was injected in a microfluidic channel engraved on polymethyl methacrylate (PMMA) to achieve frequency switching. Numerical simulation and experimental results are presented for two cases: when the microfluidic channels are empty, and when they are filled with liquid metal. To evaluate the performance of the fabricated absorber prototype, it is tested with a rectangular waveguide. The resonant frequency was successfully switched from 10.96 GHz to 10.61 GHz after injecting liquid metal while maintaining absorptivity higher than 98%.

  11. Frequency-Switchable Metamaterial Absorber Injecting Eutectic Gallium-Indium (EGaIn) Liquid Metal Alloy

    PubMed Central

    Ling, Kenyu; Kim, Hyung Ki; Yoo, Minyeong; Lim, Sungjoon

    2015-01-01

    In this study, we demonstrated a new class of frequency-switchable metamaterial absorber in the X-band. Eutectic gallium-indium (EGaIn), a liquid metal alloy, was injected in a microfluidic channel engraved on polymethyl methacrylate (PMMA) to achieve frequency switching. Numerical simulation and experimental results are presented for two cases: when the microfluidic channels are empty, and when they are filled with liquid metal. To evaluate the performance of the fabricated absorber prototype, it is tested with a rectangular waveguide. The resonant frequency was successfully switched from 10.96 GHz to 10.61 GHz after injecting liquid metal while maintaining absorptivity higher than 98%. PMID:26561815

  12. Disposal of liquid wastes by injection underground--Neither myth nor millennium

    USGS Publications Warehouse

    Piper, Arthur M.

    1969-01-01

    Injecting liquid wastes deep underground is an attractive but not necessarily practical means for disposing of them. For decades, impressive volumes of unwanted oil-field brine have been injected, currently about 10,000 acre-feet yearly. Recently, liquid industrial wastes are being injected in ever-increasing quantity. Dimensions of industrial injection wells range widely but the approximate medians are: depth, 2,660 feet; thickness of injection zone, 185 feet; injection rate, 135 gallons per minute; wellhead injection pressure, 185 pounds per square inch. Effects of deep injection are complex and not all are understood clearly. In a responsible society, injection cannot be allowed to put wastes out of mind. Injection is no more than storage--for all time in the case of the most intractable wastes--in underground space of which little is attainable in some areas and which is exhaustible in most areas. Liquid wastes range widely in character and concentration-some are incompatible one with another or with materials of the prospective injection zone; some which are reactive or chemically unstable would require pretreatment or could not be injected. Standards by which to categorize the wastes are urgently desirable. To the end that injection may be planned effectively and administered in orderly fashion, there is proposed an immediate and comprehensive canvass of all the United States to outline injection provinces and zones according to their capacities to accept waste. Much of the information needed to this end is at hand. Such a canvass would consider (1) natural zone, of groundwater circulation, from rapid to stagnant, (2) regional hydrodynamics, (3) safe injection pressures, and (4) geochemical aspects. In regard to safe pressure, definitive criteria would be sought by which to avoid recurrence of earthquake swarms such as seem to have been triggered by injection at the Rocky Mountain Arsenal well near Denver, Colo. Three of the 50 States--Missouri, .Ohio, and

  13. Circulation convection during subsurface injection of liquid waste, St. Petersburg, Florida

    USGS Publications Warehouse

    Hickey, J.J.

    1989-01-01

    Injection of liquid waste into a highly transmissive, saltwater-bearing, fractured dolomite underlying the city of St. Petersburg, Florida, provided an opportunity to study density-dependent flow associated with two miscible and density-different liquids. The injection zone was 98 m thick with a radial hydraulic conductivity of 762 m/d and a vertical hydraulic conductivity of 152 m/d. Mean chloride concentrations of the injectant during two tests of 91 and 366 days duration were 180 and 170 mg/L, respectively, whereas chloride concentration of native salt water ranged from 19,000 to 20,000 mg/L. During the 366-day test, chloride concentration in water from a well open to the upper part of the injection zone 223 m from the injection well approximately stabilized at about 4000 mg/L. Relatively constant chloride concentrations in water from this observation well at a level significantly greater than the injectant concentration suggested the hypothesis that circular convection with saltwater flow added chloride ions to the injection zone flow sampled at the observation well. In order to assess the acceptability of the circular convection hypothesis, information was required about the velocity field during injection. Mass transport model simulations were used to provide this information, after determining that the fractured injection zone could be treated as an equivalent porous medium with a single porosity. The mass transport model was calibrated using the 91-day test data from two observation wells 223 m from the injection well. The model was then run without parameter changes to simulate the 366-day test. Mass fractions of injectant computed for four observation wells during the 366-day test compared favorably with observed mass fractions. Observed mass fractions were calculated as a function of chloride concentration and density. Comparisons between model-computed mass fraction and velocity fields in a radial section showed circular convection, with salt water

  14. Data requirements for simulation of hydrogeologic effects of liquid waste injection, Harrison and Jackson Counties, Mississippi

    USGS Publications Warehouse

    Rebich, Richard A.

    1994-01-01

    Available literature and data were reviewed to quantify data requirements for computer simulation of hydrogeologic effects of liquid waste injection in southeastern Mississippi. Emphasis of each review was placed on quantifying physical properties of current Class I injection zones in Harrison and Jackson Counties. Class I injection zones are zones that are used for injection of hazardous or non-hazardous liquid waste below a formation containing the lowermost underground source of drinking water located within one-quarter of a mile of the injection well. Several mathematical models have been developed to simulate injection effects. The Basic Plume Method was selected because it is commonly used in permit applications, and the Intercomp model was selected because it is generally accepted and used in injection-related research. The input data requirements of the two models were combined into a single data requirement list inclusive of physical properties of injection zones only; injected waste and well properties are not included because such information is site-specific by industry, which is beyond the scope of this report. Results of the reviews of available literature and data indicated that Class I permit applications and standard-reference chemistry and physics texts were the primary sources of information to quantify physical properties of injection zones in Harrison and Jackson Counties. With the exception of a few reports and supplementary data for one injection zone in Jackson County, very little additional information pertaining to physical properties of the injection zones was available in sources other than permit applications and standard-reference texts.

  15. Transient dynamics of spin-polarized injection in helical Luttinger liquids

    NASA Astrophysics Data System (ADS)

    Calzona, A.; Carrega, M.; Dolcetto, G.; Sassetti, M.

    2015-11-01

    We analyze the time evolution of spin-polarized electron wave packets injected into the edge states of a two-dimensional topological insulator. In the presence of electron interactions, the system is described as a helical Luttinger liquid and injected electrons fractionalize. However, because of the presence of metallic detectors, no evidences of fractionalization are encoded in dc measurements, and in this regime the system does not show deviations from its non-interacting behavior. Nevertheless, we show that the helical Luttinger liquid nature emerges in the transient dynamics, where signatures of charge/spin fractionalization can be clearly identified.

  16. Reprint of : Transient dynamics of spin-polarized injection in helical Luttinger liquids

    NASA Astrophysics Data System (ADS)

    Calzona, A.; Carrega, M.; Dolcetto, G.; Sassetti, M.

    2016-08-01

    We analyze the time evolution of spin-polarized electron wave packets injected into the edge states of a two-dimensional topological insulator. In the presence of electron interactions, the system is described as a helical Luttinger liquid and injected electrons fractionalize. However, because of the presence of metallic detectors, no evidences of fractionalization are encoded in dc measurements, and in this regime the system does not show deviations from its non-interacting behavior. Nevertheless, we show that the helical Luttinger liquid nature emerges in the transient dynamics, where signatures of charge/spin fractionalization can be clearly identified.

  17. Delayed granulomatous reactions to facial cosmetic injections of polymethylmethacrylate microspheres and liquid injectable silicone: A case series.

    PubMed

    Friedmann, Daniel P; Kurian, Anil; Fitzpatrick, Richard E

    2016-06-01

    Polymethylmethacrylate microsphere (PMMA) and liquid injectable silicone (LIS) fillers are non-biodegradable, synthetic polymers utilized for long-term soft-tissue augmentation. Delayed granulomatous reactions to permanent fillers are a rare yet significant event that can occur months to years post procedure and are often refractory to treatment and associated with significant cosmetic morbidity. We report a case series of 4 patients who developed granulomatous reactions to PMMA or LIS, 15 months to 5 years post injection. The etiology of granulomatous reactions to permanent fillers is still poorly understood, with foreign-body reactions and/or biofilms purported to play a role. Real-time biochemical analysis with polymerase chain reaction should be performed when the index of suspicion for the presence of a biofilm is high.

  18. An automatic, vigorous-injection assisted dispersive liquid-liquid microextraction technique for stopped-flow spectrophotometric detection of boron.

    PubMed

    Alexovič, Michal; Wieczorek, Marcin; Kozak, Joanna; Kościelniak, Paweł; Balogh, Ioseph S; Andruch, Vasil

    2015-02-01

    A novel automatic vigorous-injection assisted dispersive liquid-liquid microextraction procedure based on the use of a modified single-valve sequential injection manifold (SV-SIA) was developed and applied for determination of boron in water samples. The major novelties in the procedure are the achieving of efficient dispersive liquid-liquid microextraction by means of single vigorous-injection (250 µL, 900 µL s(-1)) of the extraction solvent (n-amylacetate) into aqueous phase resulting in the effective dispersive mixing without using dispersive solvent and after self-separation of the phases, as well as forwarding of the extraction phase directly to a Z-flow cell (10 mm) without the use of a holding coil for stopped-flow spectrophotometric detection. The calibration working range was linear up to 2.43 mg L(-1) of boron at 426nm wavelength. The limit of detection, calculated as 3s of a blank test (n=10), was found to be 0.003 mg L(-1), and the relative standard deviation, measured as ten replicable concentrations at 0.41 mg L(-1) of boron was determined to be 5.6%. The validation of the method was tested using certified reference material.

  19. A CFD Model for High Pressure Liquid Poison Injection for CANDU-6 Shutdown System No. 2

    SciTech Connect

    Bo Wook Rhee; Chang Jun Jeong; Hye Jeong Yun; Dong Soon Jang

    2002-07-01

    In CANDU reactor one of the two reactor shutdown systems is the liquid poison injection system which injects the highly pressurized liquid neutron poison into the moderator tank via small holes on the nozzle pipes. To ensure the safe shutdown of a reactor it is necessary for the poison curtains generated by jets provide quick, and enough negative reactivity to the reactor during the early stage of the accident. In order to produce the neutron cross section necessary to perform this work, the poison concentration distribution during the transient is necessary. In this study, a set of models for analyzing the transient poison concentration induced by this high pressure poison injection jet activated upon the reactor trip in a CANDU-6 reactor moderator tank has been developed and used to generate the poison concentration distribution of the poison curtains induced by the high pressure jets injected into the vacant region between the pressure tube banks. The poison injection rate through the jet holes drilled on the nozzle pipes is obtained by a 1-D transient hydrodynamic code called, ALITRIG, and this injection rate is used to provide the inlet boundary condition to a 3-D CFD model of the moderator tank based on CFX4.3, a CFD code, to simulate the formation of the poison jet curtain inside the moderator tank. For validation, an attempt was made to validate this model against a poison injection experiment performed at BARC. As conclusion this set of models is judged to be appropriate. (authors)

  20. Light propagation in the micro-size capillary injected by high temperature liquid

    NASA Astrophysics Data System (ADS)

    Li, Yan-jun; Li, Edward; Xiao, Hai

    2016-11-01

    The high temperature liquid is injected into the micro-size capillary and its light propagation behavior is investigated. We focus on two different liquid pumping methods. The first method can pump the high temperature liquid tin into the micro-size capillary by using a high pressure difference system. After pumping, a single mode fiber (SMF) connected with the optical carrier based microwave interferometry (OCMI) system is used to measure different liquid tin levels in the micro-size capillary. The second method can pump the room temperature engine oil into the capillary by using a syringe pump. This method can avoid the air bubbles when the liquids are pumped into the capillary.

  1. Radiation effects on p+n InP junctions grown by MOCVD

    NASA Technical Reports Server (NTRS)

    Messenger, Scott R.; Walters, Robert J.; Panunto, M. J.; Summers, Geoffrey P.

    1994-01-01

    The superior radiation resistance of InP over other solar cell materials such as Si or GaAs has prompted the development of InP cells for space applications. The early research on radiation effects in InP was performed by Yamaguchi and co-workers who showed that, in diffused p-InP junctions, radiation-induced defects were readily annealed both thermally and by injection, which was accompanied by significant cell recovery. More recent research efforts have been made using p-InP grown by metalorganic chemical vapor deposition (MOCVD). While similar deep level transient spectroscopy (DLTS) results were found for radiation induced defects in these cells and in diffused junctions, significant differences existed in the annealing characteristics. After injection annealing at room temperature, Yamaguchi noticed an almost complete recovery of the photovoltaic parameters, while the MOCVD samples showed only minimal annealing. In searching for an explanation of the different annealing behavior of diffused junctions and those grown by MOCVD, several possibilities have been considered. One possibility is the difference in the emitter structure. The diffused junctions have S-doped graded emitters with widths of approximately 0.3 micrometers, while the MOCVD emitters are often doped with Si and have widths of approximately 300A (0.03 micrometers). The difference in the emitter thickness can have important effects, e.g. a larger fraction of the total photocurrent is generated in the n-type material for thicker emitters. Therefore the properties of the n-InP material may explain the difference in the observed overall annealing behavior of the cells.

  2. Multiple-orifice liquid injection into hypersonic airstreams and applications to ram C-3 flight

    NASA Technical Reports Server (NTRS)

    Weaver, W. L.

    1972-01-01

    Experimental data are presented for the oblique injection of water and three electrophilic liquids (fluorocarbon compounds) through multiple-orifice nozzles from a flat plate and the sides of a hemisphere-cone (0.375 scale of RAM C spacecraft) into hypersonic airstreams. The nozzle patterns included single and multiple orifices, single rows of nozzles, and duplicates of the RAM C-III nozzles. The flat-plate tests were made at Mach 8. Total pressure was varied from 3.45 MN/m2 to 10.34 MN/m2, Reynolds number was varied form 9,840,000 per meter to 19,700,000 per meter, and liquid injection pressure was varied from 0.69 MN/m2 to 3.5 MN/m2. The hemisphere-cone tests were made at Mach 7.3. Total pressure was varied from 1.38 MN/m2, to 6.89 MN/m2, Reynolds number was varied from 3,540,000 per meter to 17,700,000 per meter, and liquid-injection pressure was varied from 0.34 MN/m2 to 4.14 MN/m2. Photographs of the tests and plots of liquid-penetration and spray cross-section area are presented. Maximum penetration was found to vary as the square root of the dynamic-pressure ratio and the square root of the total injection nozzle area. Spray cross-section area was linear with maximum penetration. The test results are used to compute injection parameters for the RAM C-3 flight injection experiment.

  3. Injectable calcium phosphate cement: effects of powder-to-liquid ratio and needle size.

    PubMed

    Burguera, Elena F; Xu, Hockin H K; Sun, Limin

    2008-02-01

    Calcium phosphate cement (CPC) sets in situ and forms apatite with excellent osteoconductivity and bone-replacement capability. The objectives of this study were to formulate an injectable tetracalcium phosphate-dicalcium phosphate cement (CPC(D)), and investigate the powder/liquid ratio and needle-size effects. The injection force (mean +/- SD; n = 4) to extrude the paste increased from (8 +/- 2) N using a 10-gauge needle to (144 +/- 17) N using a 21-gauge needle (p < 0.05). With the 10-gauge needle, the mass percentage of extruded paste was (95 +/- 4)% at a powder/liquid ratio of 3; it decreased to (70 +/- 12)% at powder/liquid = 3.5 (p < 0.05). A relationship was established between injection force, F, and needle lumen cross-sectional area, A: F = 5.0 + 38.7/A(0.8). Flexural strength, S, (mean +/- SD; n = 5) increased from (5.3 +/- 0.8) MPa at powder/liquid= 2 to (11.0 +/- 0.8) MPa at powder/liquid = 3.5 (p < 0.05). Pore volume fraction, P, ranged from 62.4% to 47.9%. A relationship was established: S = 47.7 x (1 - P)(2.3). The strength of the injectable CPC(D) matched/exceeded the reported strengths of sintered porous hydroxyapatite implants that required machining. The novel injectable CPC(D) with a relatively high strength may be useful in filling defects with limited accessibility such as periodontal repair and tooth root-canal fillings, and in minimally-invasive techniques such as percutaneous vertebroplasty to fill the lesions and to strengthen the osteoporotic bone.

  4. Numerical analysis of experiments with gas injection into liquid metal coolant

    NASA Astrophysics Data System (ADS)

    Usov, E. V.; Lobanov, P. D.; Pribaturin, N. A.; Mosunova, N. A.; Chuhno, V. I.; Kutlimetov, A. E.

    2016-10-01

    Presented paper contains results of a numerical analysis of experiments with gas injection in water and liquid metal which have been performed at the Institute of Thermophysics Russian Academy of Science (IT RAS). Obtained experimental data are very important to predict processes that take place in the BREST-type reactor during the hypothetical accident with damage of the steam generator tubes, and may be used as a benchmark to validate thermo-hydraulic codes. Detailed description of models to simulate transport of gas phase in a vertical liquid column is presented in a current paper. Two-fluid model with closing relation for wall friction and interface friction coefficients was used to simulate processes which take place in a liquid during injection of gaseous phase. It has being shown that proposed models allow obtaining a good agreement between experimental data and calculation results.

  5. Liquid-phase dispersion during injection into vapor-dominated reservoirs

    SciTech Connect

    Pruess, K.

    1994-01-01

    The behavior of water injection plumes in vapor-dominated reservoirs is examined. Stressing the similarity to water infiltration in heterogeneous soils, we suggest that ever-present heterogeneities in individual fractures and fracture networks will cause a lateral broadening of descending injection plumes. The process of lateral spreading of liquid phase is viewed in analogy to transverse dispersion in miscible displacement. To account for the postulated ``phase dispersion`` the conventional two-phase immiscible flow theory is extended by adding a Fickian-type dispersive term. The validity of the proposed phase dispersion model is explored by means of simulations with detailed resolution of small-scale heterogeneity. We also present an illustrative application to injection into a depleted vapor zone. It is concluded that phase dispersion effects will broaden descending injection plumes, with important consequences for pressure support and potential water breakthrough at neighboring production wells.

  6. An application of the focused liquid jet: needle free drug injection system

    NASA Astrophysics Data System (ADS)

    Kiyama, Akihito; Katsuta, Chihiro; Kawamoto, Sennosuke; Endo, Nanami; Tanaka, Akane; Tagawa, Yoshiyuki

    2016-11-01

    Recently, a focused liquid jet draws great attention since it can be applied to various applications (e. g. Ink jet printing, medical devices). In our research, in order to discuss its applicability for a needle-free drug injection system, we shoot a focused liquid jet to an animal skin with very high-speed. Previously, the penetration of this jet into a gelatin and an artificial skin has been performed in order to model of the jet penetration process. However, experiment for jet injection into the animal skin has not been conducted yet. In this presentation, we inject ink as the liquid jet into the skin of the hairless rat. We observe the top/back view and the cross-sectional view of the injected (ink-stained) skin. We capture the stained area of the skin in order to find characteristics of the jet penetration. We discuss the criteria for the jet penetration into the skin. This work was supported by JSPS KAKENHI Grant Numbers JP26709007, JP16J08521.

  7. Thickness and Closure Kinetics of the Suprachoroidal Space Following Microneedle Injection of Liquid Formulations

    PubMed Central

    Chiang, Bryce; Venugopal, Nitin; Grossniklaus, Hans E.; Jung, Jae Hwan; Edelhauser, Henry F.; Prausnitz, Mark R.

    2017-01-01

    Purpose To determine the effect of injection volume and formulation of a microneedle injection into the suprachoroidal space (SCS) on SCS thickness and closure kinetics. Methods Microneedle injections containing 25 to 150 μL Hanks' balanced salt solution (HBSS) were performed in the rabbit SCS ex vivo. Distribution of SCS thickness was measured by ultrasonography and three-dimensional (3D) cryo-reconstruction. Microneedle injections were performed in the rabbit SCS in vivo using HBSS, Discovisc, and 1% to 5% carboxymethyl cellulose (CMC) in HBSS. Ultrasonography was used to track SCS thickness over time. Results Increasing HBSS injection volume increased the area of expanded SCS, but did not increase SCS thickness ex vivo. With SCS injections in vivo, the SCS initially expanded to thicknesses of 0.43 ± 0.06 mm with HBSS, 1.5 ± 0.4 mm with Discovisc, and 0.69 to 2.1 mm with 1% to 5% CMC. After injection with HBSS, Discovisc, and 1% CMC solution, the SCS collapsed to baseline with time constants of 19 minutes, 6 hours, and 2.4 days, respectively. In contrast, injections with 3% to 5% CMC solution resulted in SCS expansion to 2.3 to 2.8 mm over the course of 2.8 to 9.1 hours, after which the SCS collapsed to baseline with time constants of 4.5 to 9.2 days. Conclusions With low-viscosity formulations, SCS expands to a thickness that remains roughly constant, independent of the volume of fluid injected. Increasing injection fluid viscosity significantly increased SCS thickness. Expansion of the SCS is hypothesized to be controlled by a balance between the viscous forces of the liquid formulation and the resistive biomechanical forces of the tissue. PMID:28125842

  8. A field test of a waste containment technology using a new generation of injectable barrier liquids

    SciTech Connect

    Moridis, G.; Apps, J.; Persoff, P.; Myer, L.; Muller, S.; Pruess, K.; Yen, P.

    1996-08-01

    A first stage field injection of a new generation of barrier liquids was successfully completed. Two types of barrier liquids, colloidal silica (CS) and polysiloxane (PSX), were injected into heterogeneous unsaturated deposits of sand, silt, and gravel typical of many of the arid DOE cleanup sites and particularly analogous to the conditions of the Hanford Site. Successful injection by commercially available chemical grouting equipment and the tube-a-manchette technique was demonstrated. Excavation of the grout bulbs permitted visual evaluation of the soil permeation by the grout, as well as sample collection. Both grouts effectively permeated all of the formation. The PSX visually appeared to perform better, producing a more uniform and symmetric permeation regardless of heterogeneity, filling large as well as small pores and providing more structural strength than the CS. Numerical simulation of the injection tests incorporated a stochastic field to represent site heterogeneity and was able to replicate the general test behavior. Tiltmeters were used successfully to monitor surface displacements during grout injection.

  9. Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

    SciTech Connect

    Pruess, K.; Oldenburg, C.; Moridis, G.; Finsterle, S.

    1997-12-31

    This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport. A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.

  10. Large Eddy Simulation of a Cavitating Multiphase Flow for Liquid Injection

    NASA Astrophysics Data System (ADS)

    Cailloux, M.; Helie, J.; Reveillon, J.; Demoulin, F. X.

    2015-12-01

    This paper presents a numerical method for modelling a compressible multiphase flow that involves phase transition between liquid and vapour in the context of gasoline injection. A discontinuous compressible two fluid mixture based on the Volume of Fluid (VOF) implementation is employed to represent the phases of liquid, vapour and air. The mass transfer between phases is modelled by standard models such as Kunz or Schnerr-Sauer but including the presence of air in the gas phase. Turbulence is modelled using a Large Eddy Simulation (LES) approach to catch instationnarities and coherent structures. Eventually the modelling approach matches favourably experimental data concerning the effect of cavitation on atomisation process.

  11. Magma Interactions in Rhyolite Reservoirs Caused by Injection of New Rhyolitic Liquid: Results From Analogue Modeling

    NASA Astrophysics Data System (ADS)

    Girard, G.; Stix, J.

    2006-12-01

    Recharge of magma chambers by new inputs of magma is often identified as a trigger for eruptions. However, most studies to date have been carried out on mafic to intermediate composition melts replenishing mafic to silicic reservoirs, often with large compositional differences. Here we focus on rhyolites at large silicic centers such as Yellowstone where no differentiated material other than rhyolite is erupted. We investigate the behavior of rhyolite magma intruding reservoirs of similar composition and temperature, by using analogue experiments with water/corn syrup solutions as analogue magma. The density and viscosity of these solutions range from 1130 to 1320 kg m-3 and 0.008 to 8 Pa s, respectively. The fate of the injected liquid is mainly controlled by the density difference between the injected and resident liquids. Intruding material denser than resident liquid is not able to rise into the reservoir, instead building a flat basal layer or a cone above the discharge point. No further interaction such as mixing occurs. Buoyant injected material rises vertically to the top of the reservoir, also with little interaction involving resident liquid during its ascent. The injected fluid eventually spreads at the top of the reservoir, followed by mixing with the resident phase through the entire reservoir. Variables such as injection rate and viscosity mostly influence the timing and duration of this sequence of events, without changing the final result. The presence of a basal crystal mush, modeled by adding Elvacite plastic grains of 0.15 mm diameter with a density of 1160 kg m-3, does not influence the behavior of a slightly buoyant injection; the injected fluid creates its own path through the mush, eventually rising to the top of the liquid upper part of the reservoir. At the beginning of the injection, however, the intruding liquid must establish a path through the mush. At this stage, the intruding fluid violently entrains substantial numbers of particles

  12. Biomaterials Used in Injectable Implants (Liquid Embolics) for Percutaneous Filling of Vascular Spaces

    SciTech Connect

    Jordan, Olivier Doelker, Eric; Ruefenacht, Daniel A.

    2005-06-15

    The biomaterials currently used in injectable implants (liquid embolics) for minimally invasive image-guided treatment of vascular lesions undergo, once injected in situ, a phase transition based on a variety of physicochemical principles. The mechanisms leading to the formation of a solid implant include polymerization, precipitation and cross-linking through ionic or thermal process. The biomaterial characteristics have to meet the requirements of a variety of treatment conditions. The viscosity of the liquid is adapted to the access instrument, which can range from 0.2 mm to 3 mm in diameter and from a few centimeters up to 200 cm in length. Once such liquid embolics reach the vascular space, they are designed to become occlusive by inducing thrombosis or directly blocking the lesion when hardening of the embolics occurs. The safe delivery of such implants critically depends on their visibility and their hardening mechanism. Once delivered, the safety and effectiveness issues are related to implant functions such as biocompatibility, biodegradability or biomechanical properties. We review here the available and the experimental products with respect to the nature of the polymer, the mechanism of gel cast formation and the key characteristics that govern the choice of effective injectable implants.

  13. Granulomatous reaction to liquid injectable silicone for gluteal enhancement: review of management options and success of doxycycline.

    PubMed

    Paul, Suchismita; Goyal, Amrita; Duncan, Lyn M; Smith, Gideon P

    2015-01-01

    Liquid injectable silicone (LIS) for cosmetic purposes has been widely available and commonly used for almost half a century. An increase in buttock augmentation procedures because of patients wanting to emulate the look of some celebrities has recently highlighted cases in the media of unsafe administration of liquid silicone injections. Severe complications including death have been reported. In this article, we report a case in which liquid silicone was injected in the patient's gluteal tissue resulting in granulomatous reactions in the surrounding tissues. The patient responded well to doxycycline, presumably because of both its antimicrobial properties and immunomodulatory effects.

  14. MOCVD of ZnO thin films for potential use as compliant layers for GaN on Si

    NASA Astrophysics Data System (ADS)

    Black, Kate; Jones, Anthony C.; Chalker, Paul R.; Gaskell, Jeffrey M.; Murray, Robert T.; Joyce, Tim B.; Rushworth, Simon A.

    2008-03-01

    This paper explores the use of nanostructured zinc oxide (ZnO) films as a compliant buffer layer for the growth of gallium nitride (GaN) on silicon substrates. Thin films of ZnO have been deposited on silicon (1 1 1) substrates by liquid injection metalorganic chemical vapour deposition (MOCVD) using dimethyl zinc-tetrahydrofuran adduct and oxygen. The use of the adduct complex avoids pre-reaction between the dialkyl zinc complex and oxygen which has been observed elsewhere. ZnO films deposited by this method were stoichiometric and of high purity, with no detectable carbon contamination. Films were deposited over a temperature range 350-550 °C, and exhibited a nanowire-like morphology. Subsequent deposition of GaN layers grown by molecular beam epitaxy (MBE) on the ZnO film resulted in the transformation of the nanowires to gallium oxide, accompanied by virtually complete removal of zinc from the layer. A heteroepitaxially oriented ( c-axis) GaN/gallium oxide/silicon structure was produced after the nitride deposition which consisted of characteristic columnar GaN with the GaN[0 0 0 1]||Si [1 1 1]. Selective area electron diffraction of the by-product oxide interlayer showed a polycrystalline-like behaviour that gave rise to a random azimuthal distribution of the GaN grains.

  15. Chemical changes in an industrial waste liquid during post-injection movement in a limestone aquifer, Pensacola, Florida

    USGS Publications Warehouse

    Ehrlich, G.G.; Godsy, E.M.; Pascale, C.A.; Vecchioli, John

    1979-01-01

    An industrial waste liquid containing organonitrile compounds and nitrate ion has been injected into the lower limestone of the Floridan aquifer near Pensacola, Florida since June 1975. Chemical analyses of water from monitor wells and backflow from the injection well indicate that organic carbon compounds are converted to CO2 and nitrate is converted to N2. These transformations are caused by bacteria immediately after injection, and are virtually completed within 100 m of the injection well. The zone near the injection well behaves like an anaerobic filter with nitrate respiring bacteria dominating the microbial flora in this zone.Sodium thiocyanate contained in the waste is unaltered during passage through the injection zone and is used to detect the degree of mixing of injected waste liquid with native water at a monitor well 312 m (712 ft) from the injection well. The dispersivity of the injection zone was calculated to be 10 m (33 ft). Analyses of samples from the monitor well indicate 80 percent reduction in chemical oxygen demand and virtually complete loss of organonitriles and nitrate from the waste liquid during passage from the injection well to the monitor well. Bacterial densities were much lower at the monitor well than in backflow from the injection well.

  16. A novel solvent extraction process with bottom gas injection for liquid waste treatment

    SciTech Connect

    Sohn, H.Y.; Doungdeethaveeratana, D.

    1996-12-31

    A novel solvent extraction process in which the emulsion is generated by bottom gas injection rather than mechanical stirring has been developed. This process has a number of advantages over the mixer-settler unit or the spray column in terms of simple equipment configuration and the ease of cleaning and process control while providing a large interfacial area for mass transfer. The equipment consists of a horizontal cylindrical vessel in which the two immiscible liquids flow countercurrently. High-strength gas jets are injected from the bottom at certain intervals along the length of the vessel. The gas jet creates a plume zone consisting of an emulsion of the two liquids which contains a large interfacial area for rapid mass transfer. The two liquids then disengage and flow in the opposite directions before entering another plume zone. Thus, the process combines the simplicity of a cylindrical vessel, having no moving parts, with the contacting efficiency of a mixer-settler. The gas can be recycled in a closed loop, thus eliminating mist and other emission problems. These advantages would be especially significant for treating large-volume/low-value liquid streams which contain hazardous substances and/or suspended solid particulates. 6 refs., 5 figs., 2 tabs.

  17. Flow rate dependent extra-column variance from injection in capillary liquid chromatography.

    PubMed

    Aggarwal, Pankaj; Liu, Kun; Sharma, Sonika; Lawson, John S; Dennis Tolley, H; Lee, Milton L

    2015-02-06

    Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used.

  18. Safety-Enclosure System For MOCVD Process Chamber

    NASA Technical Reports Server (NTRS)

    Singletery, James, Jr.; Velasquez, Hugo; Warner, Joseph

    1995-01-01

    Safety-enclosure system filled with nitrogen surrounds reaction chamber in which metallo-organic chemical vapor deposition (MOCVD) performed. Designed to protect against explosions and/or escaping toxic gases and particulates. Gas-purification subsystem ensures during loading and unloading of process materials, interior of MOCVD chamber exposed to less than 1 ppm of oxygen and less than 5 ppm of water in nitrogen atmosphere. Toxic byproducts of MOCVD process collected within inert atmosphere. Enclosure strong enough to contain any fragments in unlikely event of explosion.

  19. Emissions Prediction and Measurement for Liquid-Fueled TVC Combustor with and without Water Injection

    NASA Technical Reports Server (NTRS)

    Brankovic, A.; Ryder, R. C., Jr.; Hendricks, R. C.; Liu, N.-S.; Shouse, D. T.; Roquemore, W. M.

    2005-01-01

    An investigation is performed to evaluate the performance of a computational fluid dynamics (CFD) tool for the prediction of the reacting flow in a liquid-fueled combustor that uses water injection for control of pollutant emissions. The experiment consists of a multisector, liquid-fueled combustor rig operated at different inlet pressures and temperatures, and over a range of fuel/air and water/fuel ratios. Fuel can be injected directly into the main combustion airstream and into the cavities. Test rig performance is characterized by combustor exit quantities such as temperature and emissions measurements using rakes and overall pressure drop from upstream plenum to combustor exit. Visualization of the flame is performed using gray scale and color still photographs and high-frame-rate videos. CFD simulations are performed utilizing a methodology that includes computer-aided design (CAD) solid modeling of the geometry, parallel processing over networked computers, and graphical and quantitative post-processing. Physical models include liquid fuel droplet dynamics and evaporation, with combustion modeled using a hybrid finite-rate chemistry model developed for Jet-A fuel. CFD and experimental results are compared for cases with cavity-only fueling, while numerical studies of cavity and main fueling was also performed. Predicted and measured trends in combustor exit temperature, CO and NOx are in general agreement at the different water/fuel loading rates, although quantitative differences exist between the predictions and measurements.

  20. Enhanced sensitivity in flow injection analysis using a long pathlength liquid waveguide capillary flow cell for spectrophotometric detection.

    PubMed

    Zhang, Jia-Zhong

    2006-01-01

    Incorporation of a liquid waveguide capillary flow cell into a flow injection instrument enhances the sensitivity of flow injection analysis with spectrophotometric detection by two orders of magnitude. Nitrite determination at nM levels has been used to demonstrate the feasibility of this novel technique for trace analysis. Combining the long pathlength spectrophotometry with flow injection analysis, this technique has advantages of low detection limit, good precision and high sample throughput.

  1. Determination of hexazinone in groundwater by direct-injection high-performance liquid chromatography.

    PubMed

    Perkins, L B; Bushway, R J; Katz, L E

    1999-01-01

    Hexazinone has been detected at levels ranging from 0.2 to 50 micrograms/L in many groundwater samples from eastern Maine over the past decade. A rapid and inexpensive direct-injection high-performance liquid chromatographic (HPLC) method has been developed to monitor contamination levels of the herbicide. The method is sensitive (limit of quantitation = 0.33 microgram/L) and is linear to 33.0 micrograms/L (R2 = 0.9995). Direct injection results from 50 field samples compared well (R2 = 0.98) with an HPLC method using solid-phase extraction for concentration and cleanup. The technique is very reproducible (coefficients of variation of 0-8.4% within day and 3.0-13.2% between day) and eliminates loss of analyte because of fewer steps in the procedure.

  2. Injection of liquid carbon dioxide into a reservoir partially saturated with methane hydrate

    NASA Astrophysics Data System (ADS)

    Shagapov, V. Sh.; Khasanov, M. K.; Musakaev, N. R.

    2016-11-01

    A mathematical model is proposed to describe methane-carbon dioxide replacement in gas hydrate by injecting liquid carbon dioxide into a porous medium initially saturated with methane and its hydrate. Self-similar solutions of the axisymmetric problems are constructed that describe the distribution of the main parameters of the reservoir. It is shown that there exist solutions according to which the process can occur both with and without boiling of carbon dioxide. Diagrams of the existence of each type of solution are constructed.

  3. Liquid metal ion source assembly for external ion injection into an electron string ion source (ESIS)

    NASA Astrophysics Data System (ADS)

    Segal, M. J.; Bark, R. A.; Thomae, R.; Donets, E. E.; Donets, E. D.; Boytsov, A.; Ponkin, D.; Ramsdorf, A.

    2016-02-01

    An assembly for a commercial Ga+ liquid metal ion source in combination with an ion transportation and focusing system, a pulse high-voltage quadrupole deflector, and a beam diagnostics system has been constructed in the framework of the iThemba LABS (Cape Town, South Africa)—JINR (Dubna, Russia) collaboration. First, results on Ga+ ion beam commissioning will be presented. Outlook of further experiments for measurements of charge breeding efficiency in the electron string ion source with the use of external injection of Ga+ and Au+ ion beams will be reported as well.

  4. Liquid metal ion source assembly for external ion injection into an electron string ion source (ESIS)

    SciTech Connect

    Segal, M. J.; Bark, R. A.; Thomae, R.; Donets, E. E.; Donets, E. D.; Boytsov, A.; Ponkin, D.; Ramsdorf, A.

    2016-02-15

    An assembly for a commercial Ga{sup +} liquid metal ion source in combination with an ion transportation and focusing system, a pulse high-voltage quadrupole deflector, and a beam diagnostics system has been constructed in the framework of the iThemba LABS (Cape Town, South Africa)—JINR (Dubna, Russia) collaboration. First, results on Ga{sup +} ion beam commissioning will be presented. Outlook of further experiments for measurements of charge breeding efficiency in the electron string ion source with the use of external injection of Ga{sup +} and Au{sup +} ion beams will be reported as well.

  5. Point-to-plane and plane-to-plane electrostatic charge injection atomization for insulating liquids

    NASA Astrophysics Data System (ADS)

    Malkawi, Ghazi

    An electrostatic charge injection atomizer was fabricated and used to introduce and study the electrostatic charge injection atomization methods for highly viscous vegetable oils and high conductivity low viscosity aviation fuel, JP8. The total, spray and leakage currents and spray breakup characteristics for these liquids were investigated and compared with Diesel fuel data. Jet breakup and spray atomization mechanism showed differences for vegetable oils and lower viscosity hydrocarbon fuels. For vegetable oils, a bending/spinning instability phenomenon was observed similar to the phenomenon found in liquid jets of high viscosity polymer solutions. The spray tip lengths and cone angles were presented qualitatively and quantitatively and correlated with the appropriate empirical formulas. The different stages of the breakup mechanisms for such oils, as a function of specific charges and flow rates, were discussed. In order to make this method of atomization more suitable for practical use in high flow rate applications, a blunt face electrode (plane-to-plane) was used as the charge emitter in place of a single pointed electrode (point-to-plane). This allowed the use of a multi-orifice emitter that maintained a specific charge with the flow rate increase which could not be achieved with the needle electrode. The effect of the nozzle geometry, liquid physical properties and applied bulk flow on the spray charge, total charge, maximum critical spray specific charge and electrical efficiency compared with the needle point-to-plane atomizer results was presented. Our investigation revealed that the electrical efficiency of the atomizer is dominated by the charge forced convection rate rather than charge transport by ion motilities and liquid motion by the electric field. As a result of the electric coulomb forces between the electrified jets, the multi-orifice atomizer provided a unique means of dispersing the fuel in a hollow cone with wide angles making the new

  6. Morphine Injection

    MedlinePlus

    Morphine injection is used to relieve moderate to severe pain. Morphine is in a class of medications called opiate ( ... Morphine injection comes as a solution (liquid) to inject intramuscularly (into a muscle) or intravenously (into a ...

  7. Temperature coefficients and radiation induced DLTS spectra of MOCVD grown n(+)p InP solar cells

    NASA Technical Reports Server (NTRS)

    Walters, Robert J.; Statler, Richard L.; Summers, Geoffrey P.

    1991-01-01

    The effects of temperature and radiation on n(+)p InP solar cells and mesa diodes grown by metallorganic chemical vapor deposition (MOCVD) were studied. It was shown that MOCVD is capable of consistently producing good quality InP solar cells with Eff greater than 19 percent which display excellent radiation resistance due to minority carrier injection and thermal annealing. It was also shown that universal predictions of InP device performance based on measurements of a small group of test samples can be expected to be quite accurate, and that the degradation of an InP device due to any incident particle spectrum should be predictable from a measurement following a single low energy proton irradiation.

  8. Cavitation control on a 2D hydrofoil through a continuous tangential injection of liquid: Experimental study

    NASA Astrophysics Data System (ADS)

    Timoshevskiy, M. V.; Zapryagaev, I. I.; Pervunin, K. S.; Markovich, D. M.

    2016-10-01

    In the paper, the possibility of active control of a cavitating flow over a 2D hydrofoil that replicates a scaled-down model of high-pressure hydroturbine guide vane (GV) was tested. The flow manipulation was implemented by a continuous tangential liquid injection at different flow rates through a spanwise slot in the foil surface. In experiments, the hydrofoil was placed in the test channel at the attack angle of 9°. Different cavitation conditions were reached by varying the cavitation number and injection velocity. In order to study time dynamics and spatial patterns of partial cavities, high-speed imaging was employed. A PIV method was used to measure the mean and fluctuating velocity fields over the hydrofoil. Hydroacoustic measurements were carried out by means of a pressure transducer to identify spectral characteristics of the cavitating flow. It was found that the present control technique is able to modify the partial cavity pattern (or even totally suppress cavitation) in case of stable sheet cavitation and change the amplitude of pressure pulsations at unsteady regimes. The injection technique makes it also possible to significantly influence the spatial distributions of the mean velocity and its turbulent fluctuations over the GV section for non-cavitating flow and sheet cavitation.

  9. Taking into account both preparation and injection in high-performance liquid chromatography linearity studies

    PubMed

    Vial; Jardy

    2000-05-01

    As mentioned in International Conference on Harmonisation publications, linearity is a principal parameter in method validation. The most popular statistical tool used is linear least-squares regression. Contrary to what is still very often practiced, the correlation coefficient can in no way be considered as an indicator of the fit quality. There is in fact a test called the "lack-of-fit test" that enables one to answer the question, "Is the linear model adapted to the calibration curve?". However, this test can give erroneous conclusions when, at each level, several sources of variation for the response are influent. It often occurs in high-performance liquid chromatography, as shown in a following example, where the calibration curve is obtained from repeated injections of repeated dilutions of a parent solution. The lack-of-fit test rejected linearity, although it was at least questionable. In fact, the reason for a discrepancy of this kind lies in the presence of a double source of variation: injection and dilution. It is possible to overcome the problem by mixing a nested ANOVA with the standard least-square linear regression. As shown in an example, implementing this methodology for data processing allows one not only to carry out an unbiased lack-of-fit test but also give estimates of the dispersion introduced respectively by the preparation and the injection.

  10. Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding

    PubMed Central

    Chung, Philip; Heller, J. Alex; Etemadi, Mozziyar; Ottoson, Paige E.; Liu, Jonathan A.; Rand, Larry; Roy, Shuvo

    2014-01-01

    Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications. PMID:24998993

  11. Rapid and low-cost prototyping of medical devices using 3D printed molds for liquid injection molding.

    PubMed

    Chung, Philip; Heller, J Alex; Etemadi, Mozziyar; Ottoson, Paige E; Liu, Jonathan A; Rand, Larry; Roy, Shuvo

    2014-06-27

    Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications.

  12. Analysis of linear and cyclic oligomers in polyamide-6 without sample preparation by liquid chromatography using the sandwich injection method. I. Injection procedure and column stability.

    PubMed

    Mengerink, Y; Peters, R; Kerkhoff, M; Hellenbrand, J; Omloo, H; Andrien, J; Vestjens, M; van der Wal, S

    2000-04-21

    We report a method for reliable routine polymer sample introduction with minimal bias, a separation method of the first six linear and cyclic oligomers by liquid chromatography, quantification using group equivalents and long term method performance. Injecting a polymer sample in a mobile phase containing an aqueous non-solvent often results in blocked systems as the polymer precipitates in the connecting capillaries. In this first part we focus on a new injection technique, in which the dissolved polyamide is placed between two zones of formic acid, preventing the polymer to precipitate before it reaches the column. Development of this sandwich injection method makes direct injection of the polymer into an aqueous acetonitrile gradient feasible. The oligomeric polyamide recovery of this technique, extraction, dissolution/precipitation and direct injection on a hexafluoro-isopropanol (HFIP) gradient were compared. With the sandwich injection method the polymer remains on the column, slowly changing the stationary phase. The influence of this on resolution and retention was studied. Column stability allows sixty injections before cleaning or replacing the column is necessary.

  13. Mocvd of Tin Oxide for Gas Sensors.

    NASA Astrophysics Data System (ADS)

    Weglicki, Peter Stanislaw

    1990-01-01

    Available from UMI in association with The British Library. Requires signed TDF. Thin films of a wide variety of materials can be produced using an assortment of physical and chemical techniques. Such techniques are reviewed and compared, with particular reference to the deposition of tin oxide films. In the present study, MOCVD (Metal organic chemical vapour deposition) was used to grow thin films of tin oxide from dibutyltin diacetate precursor on a variety of substrates. A series of reactor prototypes were developed in accordance with specific requirements of reproducibility and process control. The evolution of the designs leading to the final working system is detailed. The theory of MOCVD is given with particular reference to the reactor used in this project. The effects of various deposition parameters on tin oxide film growth rates were investigated, and the results are discussed with reference to the deposition kinetics in the system. Films were characterised by optical interferometry, optical and electron microscopy, X-ray diffraction, Rutherford backscattering and electrical measurements. The films were generally uniform, conducting and polycrystalline, and were comprised of very small grains, resulting in a high density. A specific application of metal oxide materials is in solid state gas sensors, which are available in various forms and operate according to different mechanisms. These are compared and a detailed account is given on the theory of operation of surface conductivity modulated devices. The application of such devices based on tin oxide in thin film form was investigated in the present work. The prepared sensor samples were comprised of very small grains, resulting in a high density. The observation that preferred (310) orientation occured in thicker films, can be attributed to dendritic growth. The sensors generally showed response to numerous reducing gas ambients, although there was evidence of a degree of selectivity against methane

  14. MICROSCALE FLOW INJECTION AND MICROBORE HIGH-PERFORMANCE LIQUID CHROMATORGRAPHY COUPLED WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY VIA A HIGH-EFFICIENCY NEBULIZER

    EPA Science Inventory

    A high-effeciency nebulizer has been used for coupling microscale flow injection and microbore high-performance liquid chromatography with inductively coupled plasma mass spectrometry (ICPMS). The microscale flow injection system was configured to minimize band broadening between...

  15. Radiative efficiency of MOCVD grown QD lasers

    NASA Astrophysics Data System (ADS)

    Mawst, Luke; Tsvid, Gene; Dudley, Peter; Kirch, Jeremy; Park, J. H.; Kim, N.

    2010-02-01

    The optical spectral gain characteristics and overall radiative efficiency of MOCVD grown InGaAs quantum dot lasers have been evaluated. Single-pass, multi-segmented amplified spontaneous emission measurements are used to obtain the gain, absorption, and spontaneous emission spectra in real units. Integration of the calibrated spontaneous emission spectra then allows for determining the overall radiative efficiency, which gives important insights into the role which nonradiative recombination plays in the active region under study. We use single pass, multi-segmented edge-emitting in which electrically isolated segments allow to vary the length of a pumped region. In this study we used 8 section devices (the size of a segment is 50x300 μm) with only the first 5 segments used for varying the pump length. The remaining unpumped segments and scribed back facet minimize round trip feedback. Measured gain spectra for different pump currents allow for extraction of the peak gain vs. current density, which is fitted to a logarithmic dependence and directly compared to conventional cavity length analysis, (CLA). The extracted spontaneous emission spectrum is calibrated and integrated over all frequencies and modes to obtain total spontaneous radiation current density and radiative efficiency, ηr. We find ηr values of approximately 17% at RT for 5 stack QD active regions. By contrast, high performance InGaAs QW lasers exhibit ηr ~50% at RT.

  16. Effects of injection pressure difference on droplet size distribution and spray cone angle in spray cooling of liquid nitrogen

    NASA Astrophysics Data System (ADS)

    Liu, Xiufang; Xue, Rong; Ruan, Yixiao; Chen, Liang; Zhang, Xingqun; Hou, Yu

    2017-04-01

    Spray cooling with liquid nitrogen as the working fluid has been widely employed in a plenty of fields requiring cooling at cryogenic temperature, such as the cryogenic wind tunnels and cooling super-conducting magnets. In this study, we built a liquid nitrogen spray system and experimentally investigated the influence of injection pressure difference on the droplet size distribution and the spray cone angle. The measurements using particle size analyser show increasing the injection pressure difference improves the atomization, as indicated by the homogenization and reduction of the droplet size. The initial spray cone angle is insensitive to the injection pressure difference. However, the far-field spray cone angle decreases dramatically with increasing the injection pressure difference. The results could enrich our knowledge of spray cooling of cryogenic fluids and benefit the design of cryogenic spray cooling systems.

  17. Qualitative detection of diuretics and acidic metabolites of other doping agents in human urine by high-performance liquid chromatography-tandem mass spectrometry: comparison between liquid-liquid extraction and direct injection.

    PubMed

    Deventer, K; Pozo, O J; Van Eenoo, P; Delbeke, F T

    2009-07-31

    Direct injection of urine has gained interest in the field of analytical toxicology, including doping control analysis. However, implementation of a direct urinalysis method for the LC-MS/MS detection of 34 diuretics and 9 other doping agents yielded several analytical problems, which were not observed using a traditional liquid-liquid extraction. Therefore a comparative study was made between liquid-liquid extraction and direct injection. Comparison of validation results showed that the liquid-liquid extraction at pH 7 allows to analyze samples without major drawbacks regarding matrix effects. Hence, good sensitivity was observed and detection limits ranged between 1 and 250 ng/mL for all compounds. In the direct injection approach shifted retention times were observed for several acidic and basic compounds due to unwanted matrix effects. This shift was reduced by a 25-fold dilution of the urine samples. Besides the improved retention time stability the diluted samples also exhibited lower ion suppression than the undiluted ones. After 25-fold dilution, detection limits ranged between 10 and 250 ng/mL for all compounds. Since these detection limits are at or below the minimum required performance level, imposed by the World Anti-Doping Agency, the method could be applied to routine anti-doping analysis. Samples, previously declared positive, were reanalysed using both the liquid-liquid extraction and direct injection. With both techniques all 26 samples were found to be positive, showing the applicability of direct injection for the analysis of diuretics.

  18. Direct liquid sample introduction for flow injection analysis and liquid chromatography with inductively coupled argon plasma spectrometric detection

    SciTech Connect

    Lawrence, K.E.; Rice, G.W.; Fassel, V.A.

    1984-02-01

    The coupling of flow injection analysis (FIA) or high-performance liquid chromatography (HPLC) techniques to inductively coupled plasma atomic emission spectrometry (ICP-AES) offers new and attractive approaches for the determination of elemental concentrations in a wide variety of sample matrices. One of the most attractive features that FIA offers is a rapid and precise means of automating sample introduction into an ICP for simultaneous, multielement analysis at the trace, minor, and major constituent level with minimal sample consumption. The utilization of the ICP as a detector for HPLC retains most of the advantages of FIA-ICP, while providing the analyst with a powerful and versatile means of compound separation. This added dimension becomes particularly important when metal speciation is of primary interest, rather than total metal content. To date, the coupling of FIA and HPLC to the ICP has only been accomplished using conventional cross-flow, concentric, or Babington-type pneumatic nebulizers. Limits of detection under these conditions have generally been observed to be poorer when compared to conventional continuous sample flow conditions. These limitations have been attributed to the large dead-volume and the sample losses associated with conventional nebulizers and band broadening of eluents from FIA transfer tubing or HPLC columns prior to entering the nebulizer unit. In an effort to resolve these difficulties, a microconcentric nebulizer has been developed which is inserted directly into the tip of a conventional sample introduction tube of an ICP torch. Preliminary data on the potential utility of direct liquid sample introduction into the ICP are presented. 12 references, 6 figures, 1 table.

  19. Ultrasound-assisted dispersive liquid-liquid microextraction of tetracycline drugs from egg supplements before flow injection analysis coupled to a liquid waveguide capillary cell.

    PubMed

    Rodríguez, Michael Pérez; Pezza, Helena Redigolo; Pezza, Leonardo

    2016-09-01

    A simple, rapid, and efficient ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) method was developed for extraction of tetracycline residues from egg supplement samples, with subsequent determination by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell (LWCC) and a controlled temperature heating bath. Tetracyclines react with diazotized p-sulfanilic acid, in a slightly alkaline medium, to form azo compounds that can be measured at 435 nm. The reaction sensitivity improved substantially (5.12-fold) using an in-line heating temperature of 45 °C. Multivariate methodology was used to optimize the factors affecting the extraction efficiency, considering the volumes of extraction and disperser solvents, sonication time, extraction time, and centrifugation time. Good linearity in the range 30-600 μg L(-1) was obtained for all the tetracyclines, with regression coefficients (r) higher than 0.9974. The limits of detection ranged from 6.4 to 11.1 μg L(-1), and the recoveries were in the range 85.7-96.4 %, with relative standard deviation lower than 9.8 %. Analyte recovery was improved by approximately 6 % when the microextraction was assisted by ultrasound. The results obtained with the proposed US-DLLME-FIA method were confirmed by a reference HPLC method and showed that the egg supplement samples analyzed were suitable for human consumption.

  20. A case of mimicking angioedema: chin silicone granulomatous reaction spreading all over the face after receiving liquid silicone injection forty years previously.

    PubMed

    Chen, Yu-Cheng; Chen, Mei-Ling; Chiu, Ying-Ming

    2011-06-01

    Liquid injectable silicone has been used for soft tissue augmentation for five decades. Many complications following liquid silicone injection have been reported. To diagnose and manage silicone granuloma remains difficult. Silicone granuloma must be diagnosed with the history of liquid silicone injection and the histology of tissue biopsy. We presented a case of granulomatous reaction after the injection of liquid silicone for chin augmentation forty years ago, causing total facial swelling, which mimicking angioedema initially. We administered methylprednisolone to the patient. Initial response to methylprednisolone was favorable.

  1. On the Design and Test of a Liquid Injection Electric Thruster

    NASA Technical Reports Server (NTRS)

    Jones, T. A.; Kenney, J. T.; Youmans, E. H.

    1973-01-01

    A liquid injection electric thruster (LINJET) was designed and tested. The results of the tests were very encouraging with thruster performance levels well in excess of design goals. Supporting activities to the engine design and test included a five-million pulse life test on the main capacitor, a 46-million pulse test on the trigger electronics, design and fabrication of a zero resistance torque connector for use with the torsional pendulum thrust stand, design and fabrication of a logic box for control of engine firing, and a physical and chemical properties characterization of the perfluorocarbon propellant. While the results were encouraging, testing was limited, as many problems existed with the design. The most significant problem was involved with excessive propellant flow which contributed to false triggering and shorting. Low power active thermal control of the propellant storage cavity, coupled with a re-evaluation of the injection ring pore size and area exposed to the main capacitor discharge are areas that should be investigated should this design be carried forward.

  2. Bulk and Surface Molecular Orientation Distribution in Injection-molded Liquid Crystalline Polymers: Experiment and Simulation

    SciTech Connect

    Fang, J.; Burghardt, W; Bubeck, R; Burgard, S; Fischer, D

    2010-01-01

    Bulk and surface distributions of molecular orientation in injection-molded plaques of thermotropic liquid crystalline polymers (TLCPs) have been studied using a combination of techniques, coordinated with process simulations using the Larson-Doi 'polydomain' model. Wide-angle X-ray scattering was used to map out the bulk orientation distribution. Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) were utilized to probe the molecular orientation states to within about {approx}5 {micro}m and {approx}2 nm, respectively, of the sample surface. These noninvasive, surface-sensitive techniques yield reasonable self-consistency, providing complementary validation of the robustness of these methods. An analogy between Larson-Doi and fiber orientation models has allowed the first simulations of TLCP injection molding. The simulations capture many fine details in the bulk orientation distribution across the sample plaque. Direct simulation of surface orientation at the level probed by FTIR-ATR and NEXAFS was not possible due to the limited spatial resolution of the simulations. However, simulation results extracted from the shear-dominant skin region are found to provide a qualitatively accurate indicator of surface orientation. Finally, simulations capture the relation between bulk and surface orientation states across the different regions of the sample plaque.

  3. MOCVD of multimetal and noble metal films

    NASA Astrophysics Data System (ADS)

    Endle, James Patrick

    2000-11-01

    Carbon content in TiN films produced with tetrakis(dimethylamino)titanium (TDMAT) and methylhydrazine or dimethylhydrazine can be controlled at or below 10% with a N/Ti ratio of ˜1.3 at growth temperatures between 573 and 723 K. Post-dosing either hydrazine on a CVD TiN film results in additional N-Ti bonds, indicating a surface reaction between the two precursors occurs. Co-dosing hydrazine-like compounds with larger alkyl ligands than methyl resulted in additional carbon incorporation in the TiN film. A growth system, consisting of a load lock and growth chamber, and a precursor pyrolysis system were designed and built to study metalorganic chemical vapor deposition. Addition of a bubbler and a direct liquid injection system allowed for the vaporization of solid and liquid precursors and solutions of multiple precursors. A precursor pyrolysis system was designed for high and low vapor pressure precursors and high carrier gas flow rates. The systems were used to study (Al,Ti)N and Ir film growth. (Al,Ti)N was used as a template to study the incorporation of elements into a multimetal chemical vapor deposited film using NH3 and a DLI solution of TDMAT and the tris(dimethylarnino)alane dimer (TDMAA) in toluene-NH 3 significantly decreases the decomposition temperature of both precursors. Carbon was reduced by increasing the NH3 partial pressure, and the Al incorporation was increased by increasing the TDMAA/TDMAT ratio in the DLI solution. Exposure to ambient resulted in significant oxygen incorporation and the removal of carbon and nitrogen from the (AI,Ti)N film. Conformal (AI,Ti)N films were produced at 450 K in the presence of NH3 and at 550 K without NH3. The role of O2 in Ir film growth was studied with the newly designed equipment. O2 significantly decreases the decomposition temperature of (MeCp)Ir(COD) below 425 K by preventing a carbonaceous build-up on the iridium film. By decreasing the oxygen partial pressure, the island nucleation and coalescence

  4. Hot Microbubble Injection in Thin Liquid Film Layers for Ammonia-Water Separation

    NASA Astrophysics Data System (ADS)

    Desai, Pratik; Zimmerman, William

    2015-11-01

    140 MT of NH3 produced p.a. barely keeps up with the global usage of this ubiquitously used commodity. NH3 manufacture & later remediation from landfill leachate to lower eco-toxicity makes further demands on the energy utilised for this ``NH3 cycle.'' Moreover, current methods for lowering eco-toxicity destroy NH3 rather than recovering it. Air stripping is a widely employed low energy industrial process used for NH3 recovery but has a long processing time- ≅24h for 60% efficiency & 100h for 95% efficiency. The solution presented herein is based on hot microbubble injection in thin liquid film layers designed to separate NH3 from NH3-H2O solutions. The transport phenomena exhibited by the microbubbles helps them separate volatile liquids effectively with negligible sensible heat transfer. This process is nearly isothermal simply because evaporation by microbubbles is controlled by internal mixing, which is fast relative to sensible heat transfer, when limited to short contact times in thin films. A 1000-3000-fold increase in mass transfer, over conventional stripping, and a 100% separation efficiency achieved in a processing time of 30 minutes is observed, potentially, if persisting with industrial scale up, resulting in a 200-fold reduction in processing time. The authors would like to acknowledge contributions from Michael Turley MEng - University of Sheffield and Richard Robinson from Viridor for their help and support as well as EPSRC Grant Number EP/K001329/1 - ``4CU''.

  5. Design and development of a helium injection system to improve external leakage detection during liquid nitrogen immersion tests

    NASA Astrophysics Data System (ADS)

    Townsend, Andrew; Mishra, Rakesh

    2016-10-01

    The testing of assemblies for use in cryogenic systems commonly includes evaluation at or near operating (therefore cryogenic) temperature. Typical assemblies include valves and pumps for use in liquid oxygen-liquid hydrogen rocket engines. One frequently specified method of cryogenic external leakage testing requires the assembly, pressurized with gaseous helium (GHe), be immersed in a bath of liquid nitrogen (LN2) and allowed to thermally stabilize. Component interfaces are then visually inspected for leakage (bubbles). Unfortunately the liquid nitrogen will be boiling under normal, bench-top, test conditions. This boiling tends to mask even significant leakage. One little known and perhaps under-utilized property of helium is the seemingly counter-intuitive thermodynamic property that when ambient temperature helium is bubbled through boiling LN2 at a temperature of -195.8 °C, the temperature of the liquid nitrogen will reduce. This paper reports on the design and testing of a novel proof-of-concept helium injection control system confirming that it is possible to reduce the temperature of an LN2 bath below boiling point through the controlled injection of ambient temperature gaseous helium and then to efficiently maintain a reduced helium flow rate to maintain a stabilized liquid temperature, enabling clear visual observation of components immersed within the LN2. Helium saturation testing is performed and injection system sizing is discussed.

  6. Direct injection isocratic high-performance liquid chromatographic analysis of mitomycin C in plasma.

    PubMed

    Song, D; Au, J L

    1996-02-09

    A direct injection high-performance liquid chromatography method is described for the determination of mitomycin C (MMC) in human plasma. The stationary phase consisted of hydrophilic and hydrophobic functional groups covalently bound to silicone-coated silica beads (CAPCELL PAK MF Ph-1, 150x4.6 mm I.D., 5 microns). A mobile phase using 100% water gave a better separation of MMC from endogenous interferences as compared to a mobile phase with 12.5% acetonitrile and 2.5 mM phosphate buffer (pH 6.9). Using water as the eluent (1 ml/min) and UV detection at 365 nm, MMC was found to elute at 5.0 min with a peak width of 0.3 min, whereas endogenous interferences eluted before 3 min. Total assay time per sample was 6 min. Internal standard was not required because the recovery of MMC was nearly complete, about 90% from 20 to 5000 ng/ml. The standard curve was linear from 20 to 5000 ng/ml in plasma, and the intra-and inter-day variation was between 3 to 6%. The lower detection limit was 5 ng/ml with a 25 microliters sample, which represents a two- to four-fold improvement over the 10 ng/ml detection limit by previous methods using liquid-liquid extraction and comparable sample size. The simplicity of this method, i.e., no sample extraction, no internal standard, 100% aqueous mobile phase, isocratic elution and short analysis time (6 min/sample), makes it suitable for large scale routine sample analysis, whereas its small sample volume requirement and high sensitivity are useful for pharmacokinetic studies in small animals where limited sample is available.

  7. Electric convection of low-conductivity liquid in a horizontal capacitor in the presence of unipolar charge injection

    NASA Astrophysics Data System (ADS)

    Il'in, V. A.

    2017-01-01

    Electric convection of low-conductivity liquid in a horizontal plane capacitor is analyzed with allowance for unipolar charge injection. Dynamics of charge transfer through stationary isothermal liquid in the presence of modulated electric field is studied. Effect of modulation amplitude and frequency on the spatiotemporal distribution of charge density and electric potential is considered. Nonlinear electric convection of nonisothermal low-conductivity liquid is studied in the presence of static electric field in a 2D system. Hysteresis transitions between two different (with respect to intensity) regimes of electric convection are analyzed.

  8. Exploring Liquid Sequential Injection Chromatography to Teach Fundamentals of Separation Methods: A Very Fast Analytical Chemistry Experiment

    ERIC Educational Resources Information Center

    Penteado, Jose C.; Masini, Jorge Cesar

    2011-01-01

    Influence of the solvent strength determined by the addition of a mobile-phase organic modifier and pH on chromatographic separation of sorbic acid and vanillin has been investigated by the relatively new technique, liquid sequential injection chromatography (SIC). This technique uses reversed-phase monolithic stationary phase to execute fast…

  9. Development of a new direct liquid injection system for nanoparticle deposition by chemical vapor deposition using nanoparticle solutions

    NASA Astrophysics Data System (ADS)

    Vervaele, Mattias; De Roo, Bert; Deschaume, Olivier; Rajala, Markku; Guillon, Herve; Sousa, Marilyne; Bartic, Carmen; Van Haesendonck, Chris; Seo, Jin Won; Locquet, Jean-Pierre

    2016-02-01

    Nanoparticles of different materials are already in use for many applications. In some applications, these nanoparticles need to be deposited on a substrate in a fast and reproducible way. We have developed a new direct liquid injection system for nanoparticle deposition by chemical vapor deposition using a liquid nanoparticle precursor. The system was designed to deposit nanoparticles in a controlled and reproducible way by using two direct liquid injectors to deliver nanoparticles to the system. The nanoparticle solution is first evaporated and then the nanoparticles flow onto a substrate inside the vacuum chamber. To allow injection and evaporation of the liquid, a direct liquid injection and vaporization system are mounted on top of the process chamber. The deposition of the nanoparticles is controlled by parameters such as deposition temperature, partial pressure of the gases, and flow rate of the nanoparticle suspension. The concentration of the deposited nanoparticles can be varied simply by changing the flow rate and deposition time. We demonstrate the capabilities of this system using gold nanoparticles. The selected suspension flow rates were varied between 0.25 and 1 g/min. AFM analysis of the deposited samples showed that the aggregation of gold nanoparticles is well controlled by the flow and deposition parameters.

  10. Investigation of oil injection into brine for the strategic petroleum reserve : hydrodynamics experiments with simulant liquids.

    SciTech Connect

    Castaneda, Jaime N.; Shollenberger, Kim Ann; Torczynski, John Robert; Cote, Raymond O.; Barney, Jeremy; O'Hern, Timothy John

    2003-10-01

    An experimental program is being conducted to study a proposed approach for oil reintroduction in the Strategic Petroleum Reserve (SPR). The goal is to assess whether useful oil is rendered unusable through formation of a stable oil-brine emulsion during reintroduction of degassed oil into the brine layer in storage caverns. This report documents the first stage of the program, in which simulant liquids are used to characterize the buoyant plume that is produced when a jet of crude oil is injected downward from a tube into brine. The experiment consists of a large transparent vessel that is a scale model of the proposed oil injection process at the SPR. An oil layer is floated on top of a brine layer. Silicon oil (Dow Corning 200{reg_sign} Fluid, 5 cSt) is used as the simulant for crude oil to allow visualization of the flow and to avoid flammability and related concerns. Sodium nitrate solution is used as the simulant for brine because it is not corrosive and it can match the density ratio between brine and crude oil. The oil is injected downward through a tube into the brine at a prescribed depth below the oil-brine interface. Flow rates are determined by scaling to match the ratio of buoyancy to momentum between the experiment and the SPR. Initially, the momentum of the flow produces a downward jet of oil below the tube end. Subsequently, the oil breaks up into droplets due to shear forces, buoyancy dominates the flow, and a plume of oil droplets rises to the interface. The interface is deflected upward by the impinging oil-brine plume. Two different diameter injection tubes were used (1/2-inch and 1-inch OD) to vary the scaling. Use of the 1-inch injection tube also assured that turbulent pipe flow was achieved, which was questionable for lower flow rates in the 1/2-inch tube. In addition, a 1/2-inch J-tube was used to direct the buoyant jet upwards rather than downwards to determine whether flow redirection could substantially reduce the oil-plume size and the

  11. Atomization and Dispersion of a Liquid Jet Injected Into a Crossflow of Air

    NASA Technical Reports Server (NTRS)

    Seay, J. E.; Samuelson, G. S.

    1996-01-01

    In recent years, environmental regulations have become more stringent, requiring lower emissions of mainly nitrogen oxides (NOx), as well as carbon monoxide (CO) and unburned hydrocarbons (UHC). These regulations have forced the gas turbine industry to examine non-conventional combustion strategies, such as the lean burn approach. The reasoning behind operating under lean conditions is to maintain the temperature of combustion near and below temperatures required for the formation of thermal nitric oxide (NO). To be successful, however, the lean processes require careful preparation of the fuel/air mixture to preclude formation of either locally rich reaction zones, which may give rise to NO formation, or locally lean reaction zones, which may give rise to inefficient fuel processing. As a result fuel preparation is crucial to the development and success of new aeroengine combustor technologies. A key element of the fuel preparation process is the fuel nozzle. As nozzle technologies have developed, airblast atomization has been adopted for both industrial and aircraft gas turbine applications. However, the majority of the work to date has focused on prefilming nozzles, which despite their complexity and high cost have become an industry standard for conventional combustion strategies. It is likely that the new strategies required to meet future emissions goals will utilize novel fuel injector approaches, such as radial injection. This thesis proposes and demonstrates an experiment to examine, on a mechanistic level (i.e., the physics of the action), the processes associated with the atomization, evaporation, and dispersion of a liquid jet introduced, from a radial, plain-jet airblast injector, into a crossflow of air. This understanding requires the knowledge not only of what factors influence atomization, but also the underlying mechanism associated with liquid breakup and dispersion. The experimental data acquired identify conditions and geometries for improved

  12. Ultrasound-assisted emulsification microextraction for the determination of ephedrines in human urine by capillary electrophoresis with direct injection. Comparison with dispersive liquid-liquid microextraction.

    PubMed

    Alshana, Usama; Göğer, Nilgün G; Ertaş, Nusret

    2012-08-01

    Ultrasound-assisted emulsification microextraction and dispersive liquid-liquid microextraction were compared for extraction of ephedrine, norephedrine, and pseudoephedrine from human urine samples prior to their determination by capillary electrophoresis. Formation of a microemulsion of the organic extract with an aqueous solution (at pH 3.2) containing 10% methanol facilitated the direct injection of the final extract into the capillary. Influential parameters affecting extraction efficiency were systematically studied and optimized. In order to enhance the sensitivity further, field-amplified sample injection was applied. Under optimum extraction and stacking conditions, enrichment factors of up to 140 and 1750 as compared to conventional capillary zone electrophoresis were obtained resulting in limits of detection of 12-33 μg/L and 1.0-2.8 μg/L with dispersive liquid-liquid microextraction and ultrasound-assisted emulsification microextraction when combined with field-amplified sample injection. Calibration graphs showed good linearity for urine samples by both methods with coefficients of determination higher than 0.9973 and percent relative standard deviations of the analyses in the range of 3.4-8.2% for (n = 5). The results showed that the use of ultrasound to assist microextraction provided higher extraction efficiencies than disperser solvents, regarding the hydrophilic nature of the investigated analytes.

  13. Ibandronate Injection

    MedlinePlus

    Boniva® Injection ... Ibandronate injection is used to treat osteoporosis (a condition in which the bones become thin and weak and break ... Ibandronate injection comes as a solution (liquid) to be injected into a vein by a doctor or nurse in ...

  14. A Comparative Review of Hydrologic Issues Involved in Geologic Storage of CO2 and Injection Disposal of Liquid Waste

    SciTech Connect

    Tsang, C.-F.; Birkholzer, J.; Rutqvist, J.

    2008-04-15

    The paper presents a comparison of hydrologic issues and technical approaches used in deep-well injection and disposal of liquid wastes, and those issues and approaches associated with injection and storage of CO{sub 2} in deep brine formations. These comparisons have been discussed in nine areas: (1) Injection well integrity; (2) Abandoned well problems; (3) Buoyancy effects; (4) Multiphase flow effects; (5) Heterogeneity and flow channeling; (6) Multilayer isolation effects; (7) Caprock effectiveness and hydrogeomechanics; (8) Site characterization and monitoring; and (9) Effects of CO{sub 2} storage on groundwater resources There are considerable similarities, as well as significant differences. Scientifically and technically, these two fields can learn much from each other. The discussions presented in this paper should help to focus on the key scientific issues facing deep injection of fluids. A substantial but by no means exhaustive reference list has been provided for further studies into the subject.

  15. Teduglutide Injection

    MedlinePlus

    ... mix and inject it.Teduglutide comes as a kit containing vials of teduglutide powder for injection, prefilled syringes containing diluent (liquid to be mixed with teduglutide powder), needles to attach to the diluent syringe, dosing syringes ...

  16. Emission of polycyclic aromatic hydrocarbons (PAHs) from the liquid injection incineration of petrochemical industrial wastewater.

    PubMed

    Wang, Lin-Chi; Wang, I-Ching; Chang, Juu-En; Lai, Soon-Onn; Chang-Chien, Guo-Ping

    2007-09-05

    This study investigated the emission of polycyclic aromatic hydrocarbons (PAHs) from stack flue gas and air pollution control device (APCD) effluent of the liquid injection incinerator (LII) disposing the petrochemical industrial wastewater, and PAH removal efficiencies of wet electrostatic precipitator (WESP) and wet scrubber (WSB). The PAH carcinogenic potency were investigated with the benzo(a)pyrene equivalent concentration (BaP(eq)). The remarkably high total-BaP(eq) concentration (220 microgNm(-3)) in the stack flue gas was much higher than those of several published emission sources, and indicated the possible influence on its surrounding environment. The total-PAH emission factors of the WESP, WSB and stack flue gas were 78.9, 95.7 and 30,900 microgL(-1) wastewater, respectively. The removal efficiencies of total-PAHs were 0.254, 0.309 and 0.563% for WESP, WSB and overall, respectively, suggesting that the use of both WESP and WSB shows insignificant PAH removal efficiencies, and 99.4% of total-PAHs was directly emitted to the ambient air through the stack flue gas. This finding suggested that the better incineration efficiencies, and APCD removal efficiencies for disposing the petrochemical industrial wastewater are necessary in future.

  17. Quantitative analysis of piroxicam using temperature-controlled ionic liquid dispersive liquid phase microextraction followed by stopped-flow injection spectrofluorimetry

    PubMed Central

    2013-01-01

    Background Piroxicam (PXM) belongs to the wide class of non-steroidal anti-inflammatory drugs (NSAIDs). PXM has been widely applied in the treatment of rheumatoid arthritis, gonarthrosis, osteoarthritis, backaches, neuralgia, mialgia. In the presented work, a green and benign sample pretreatment method called temperature-controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME) was followed with stopped-flow injection spectrofluorimetry (SFIS) for quantitation of PXM in pharmaceutical formulations and biological samples. Methods Temperature-controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME) was applied as an environmentally friendly sample enrichment method to extract and isolate PXM prior to quantitation. Dispersion of 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6]) ionic liquid (IL) through the sample aqueous solution was performed by applying a relatively high temperature. PXM was extracted into the extractor, and after phase separation, PXM in the final solution was determined by stopped-flow injection spectrofluorimetry (SFIS). Results and Major Conclusion Different factors affecting the designed method such as IL amount, diluting agent, pH and temperature were investigated in details and optimized. The method provided a linear dynamic range of 0.2-150 μg l-1, a limit of detection (LOD) of 0.046 μg l-1 and a relative standard deviation (RSD) of 3.1%. Furthermore, in order to demonstrate the analytical applicability of the recommended method, it was applied for quantitation of PXM in real samples. PMID:23895461

  18. WETTABILITY ALTERATION OF POROUS MEDIA TO GAS-WETTING FOR IMPROVING PRODUCTIVITY AND INJECTIVITY IN GAS-LIQUID FLOWS

    SciTech Connect

    Abbas Firoozabadi

    2001-10-15

    The wettability of Berea and chalk samples for gas-oil and gas-water fluids were altered from strong liquid-wetting to intermediate gas-wetting. Two polymers, FC-722 and FC-759, were used to alter the wettability. FC-759 is soluble in water and some 20 times less expensive than FC-722. Gas and liquid relative permeabilities were measured before and after wettability alteration. The results demonstrate a significant increase in liquid-phase relative permeability. Gas-phase relative permeability for a fixed saturation may increase or decrease. However, because of the very high liquid mobility and reduced liquid saturation, the gas mobility also increases for a fixed pressure drop. A number of liquid injectivity tests were also carried out. The results reveal that the liquid-phase mobility can increase significantly when the wettability of rocks is altered from strong liquid-wetting to intermediate gas-wetting. All the results show clearly that the application of wettability alteration to intermediate gas-wetting may significantly increase deliverability in gas condensate reservoirs.

  19. In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  20. In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

  1. Simultaneous determination of some food additives in soft drinks and other liquid foods by flow injection on-line dialysis coupled to high performance liquid chromatography.

    PubMed

    Kritsunankul, Orawan; Jakmunee, Jaroon

    2011-06-15

    Flow injection on-line dialysis was developed for sample pretreatment prior to the simultaneous determination of some food additives by high performance liquid chromatography (FID-HPLC). A liquid sample or mixed standard solution (900 μL) was injected into a donor stream (5%, w/v, sucrose) of FID system and was pushed further through a dialysis cell, while an acceptor solution (0.025 mol L(-1) phosphate buffer, pH 3.75) was held in the opposite side of the dialysis membrane. The dialysate was then flowed to an injection loop of the HPLC valve, where it was further injected into the HPLC system and analyzed under isocratic reverse-phase HPLC conditions and UV detection (230 nm). The order of elution of five food additives was acesulfame-K, saccharin, caffeine, benzoic acid and sorbic acid, respectively, with the analysis time of 14 min. On-line dialysis and HPLC analysis could be performed in parallel, providing sample throughput of 4.3h(-1). Dialysis efficiencies of five food additives were in ranges of 5-11%. Linear calibration graphs were in ranges of 10-100 mg L(-1) for acesulfame-K and saccharin, 10-250 mg L(-1) for benzoic acid and 10-500 mg L(-1) for caffeine and sorbic acid. Good precisions (RSD<5%) for all the additives were obtained. The proposed system was applied to soft drink and other liquid food samples. Acceptable percentage recoveries could be obtained by appropriate dilution of the sample before injecting into the system. The developed system has advantages of high degrees of automation for sample pretreatment, i.e., on-line sample separation and dilution and low consumption of chemicals and materials.

  2. Identification of the Allergenic Ingredients in Reduning Injection by Ultrafiltration and High-Performance Liquid Chromatography

    PubMed Central

    Wang, Fang; Li, Cun-yu; Zheng, Yun-feng; Li, Hong-yang; Xiao, Wei; Peng, Guo-ping

    2016-01-01

    Reduning injection is a traditional Chinese medicine injection which has multiple functions such as clearing heat, dispelling wind, and detoxification. Although Reduning injection was widely utilized, reports of its allergenicity emerged one after another. However, there is little research on its allergenic substances. The aim of this study is to evaluate the sensitization of Reduning injection and explore the underlying cause of the anaphylactic reaction. The main ingredients in Reduning injection were analyzed before and after ultrafiltration. Ultrafiltrate Reduning injection, unfiltered Reduning injection, egg albumin, Tween-80, and nine effective components in Reduning injection were utilized to sensitize guinea pigs. The serum 5-hydroxytryptamine level was used to assess the sensitization effect of Reduning injection. We found a significant decrease in Tween-80 content comparing to other components in the injection after ultrafiltration. Unfiltered Reduning injection, Tween-80, chlorogenic acid, and cryptochlorogenin acid caused remarkable anaphylactoid reaction on guinea pigs while ultrafiltration Reduning resulted in a significantly lower degree of sensitization. Our results suggest that ultrafiltration could significantly reduce the sensitization of Reduning injection, which is likely due to the decrease of Tween-80. We also conjectured that the form of chlorogenic acid and cryptochlorogenin acid within the complex solution mixture may also affect the sensitizing effect. PMID:27144180

  3. Identification of the Allergenic Ingredients in Reduning Injection by Ultrafiltration and High-Performance Liquid Chromatography.

    PubMed

    Wang, Fang; Li, Cun-yu; Zheng, Yun-feng; Li, Hong-yang; Xiao, Wei; Peng, Guo-ping

    2016-01-01

    Reduning injection is a traditional Chinese medicine injection which has multiple functions such as clearing heat, dispelling wind, and detoxification. Although Reduning injection was widely utilized, reports of its allergenicity emerged one after another. However, there is little research on its allergenic substances. The aim of this study is to evaluate the sensitization of Reduning injection and explore the underlying cause of the anaphylactic reaction. The main ingredients in Reduning injection were analyzed before and after ultrafiltration. Ultrafiltrate Reduning injection, unfiltered Reduning injection, egg albumin, Tween-80, and nine effective components in Reduning injection were utilized to sensitize guinea pigs. The serum 5-hydroxytryptamine level was used to assess the sensitization effect of Reduning injection. We found a significant decrease in Tween-80 content comparing to other components in the injection after ultrafiltration. Unfiltered Reduning injection, Tween-80, chlorogenic acid, and cryptochlorogenin acid caused remarkable anaphylactoid reaction on guinea pigs while ultrafiltration Reduning resulted in a significantly lower degree of sensitization. Our results suggest that ultrafiltration could significantly reduce the sensitization of Reduning injection, which is likely due to the decrease of Tween-80. We also conjectured that the form of chlorogenic acid and cryptochlorogenin acid within the complex solution mixture may also affect the sensitizing effect.

  4. Dispersive liquid-liquid microextraction and injection-port derivatization for the determination of free lipophilic compounds in fruit juices by gas chromatography-mass spectrometry.

    PubMed

    Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

    2017-04-28

    A method consisting of dispersive liquid-liquid microextraction (DLLME) followed by injection-port derivatization and gas chromatography-mass spectrometry (GC-MS) for the analysis of free lipophilic compounds in fruit juices is described. The method allows the analysis of several classes of lipophilic compounds, such as fatty acids, fatty alcohols, phytosterols and triterpenes. The chromatographic separation of the compounds was achieved in a chromatographic run of 25.5min. The best conditions for the dispersive liquid-liquid microextraction were 100μL of CHCl3 in 1mL of acetone. For the injection-port derivatization, the best conditions were at 280°C, 1min purge-off, and a 1:1 sample:derivatization reagent ratio (v/v) using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA):pyridine (1:1) as reagent. Quality parameters were assessed for the target compounds, giving a limits of detection (LODs) ranging from 1.1 to 5.7ng/mL and limits of quantification (LOQs) from 3.4 to 18.7ng/mL for linoleic and stearic acid, respectively. Repeatability (%RSD, n=5) was below 11.51% in all cases. In addition, the method linearity presented an r(2) ≥0.990 for all ranges applied. Finally, the method was used to test the lipophilic fraction of various samples of commercial fruit juice.

  5. Formation of Nickel Silicide from Direct-liquid-injection Chemical-vapor-deposited Nickel Nitride Films

    SciTech Connect

    Li, Z.; Gordon, R; Li, H; Shenai, D; Lavoie, C

    2010-01-01

    Smooth, continuous, and highly conformal nickel nitride (NiN{sub x}) films were deposited by direct liquid injection (DLI)-chemical vapor deposition (CVD) using a solution of bis(N,N{prime}-di-tert-butylacetamidinato)nickel(II) in tetrahydronaphthalene as the nickel (Ni) source and ammonia (NH{sub 3}) as the coreactant gas. The DLI-CVD NiNx films grown on HF-last (100) silicon and on highly doped polysilicon substrates served as the intermediate for subsequent conversion into nickel silicide (NiSi), which is a key material for source, drain, and gate contacts in microelectronic devices. Rapid thermal annealing in the forming gas of DLI-CVD NiNx films formed continuous NiSi films at temperatures above 400 C. The resistivity of the NiSi films was 15{mu}{Omega} cm, close to the value for bulk crystals. The NiSi films have remarkably smooth and sharp interfaces with underlying Si substrates, thereby producing contacts for transistors with a higher drive current and a lower junction leakage. Resistivity and synchrotron X-ray diffraction in real-time during annealing of NiNx films showed the formation of a NiSi film at about 440 C, which is morphologically stable up to about 650 C. These NiSi films could find applications in future nanoscale complementary metal oxide semiconductor devices or three-dimensional metal-oxide-semiconductor devices such as Fin-type field effect transistors for the 22 nm technology node and beyond.

  6. Quantitative measurement and mechanisms for CH4 production from hydrates with the injection of liquid CO2.

    PubMed

    Lee, Bo Ram; Koh, Carolyn A; Sum, Amadeu K

    2014-07-28

    The recovery of gas from natural gas hydrates under the permafrost and in oceanic sediments is of particular interest in energy and environmental fields because of the attractive process to release methane gas through the injection of CO2. The sequestration of CO2, a notorious greenhouse gas, in hydrates has the potential to be used in enhanced gas recovery techniques, while simultaneously releasing CH4 locked within the gas bearing hydrates. In this study, we present quantitative experiments to investigate results of possible CH4-CO2 exchange kinetics from injection of liquid CO2 through CH4 hydrates. The experiments performed use CH4 hydrate formed from ice particles (75-90 or 125-150 microns in diameter) at approximately 10.34 MPa and 263 K. In order to reduce unexpected errors, nearly full conversion (>95%) of ice particles to hydrates is achieved. Liquid CO2 is injected into the pressure cell to sweep the residual CH4 atmosphere, ensuring no free CH4 is left in the gas phase. After soaking the hydrate for several hours, CH4 is produced from the hydrates by injecting liquid CO2. The final composition and analysis of the produced CH4 is measured by using in-line gas chromatography. We also measure the CH4 moles after hydrate dissociation to confirm the closure of the total mass balance of the experiment. From these data, we infer the mechanism for CH4 production, identify the penetration depth of the dissociation/exchange on the hydrate particles, and propose physical models describing the mechanism for CH4 production. These experiments are essential in the quantification of the production of CH4 from CH4 hydrates with the injection of CO2.

  7. Controlled injection of a liquid into ultra-high vacuum: Submonolayers of adenosine triphosphate deposited on Cu(110)

    NASA Astrophysics Data System (ADS)

    Sobrado, J. M.; Martín-Gago, J. A.

    2016-10-01

    We have combined a fast-valve device with vacuum technology for implementing a new method that allows introducing liquid solutions in an ultra-high vacuum chamber in the form of very small droplets. This technical development allows the easy deposition of (bio) organic molecules or small nanoparticles on a surface in a fully in-situ process, avoiding possible contamination due to the handle of the material. Moreover, our experimental set-up is suitable for any liquid and does not require any voltage application as in electrospray. We can easily change the operating regime from liquid droplet injection to the formation of a highly dispersive jet of micro-droplets by exclusively adjusting external parameters. Due to the nature of the injection process, the operational protocol makes possible the deposition of delicate molecular species that cannot be thermally sublimated. In particular, we have used this system to study the deposition of adenosine triphosphate on Cu(110). The structure of the layer was analyzed by X-ray photoemission spectroscopy and the evolution of the signal from the deposited molecule with the number of injections indicates that the molecular coverage can be controlled with submonolayer precision.

  8. Modeling the Rapid Boil-Off of a Cryogenic Liquid When Injected into a Low Pressure Cavity

    NASA Technical Reports Server (NTRS)

    Lira, Eric

    2016-01-01

    Many launch vehicle cryogenic applications require the modeling of injecting a cryogenic liquid into a low pressure cavity. The difficulty of such analyses lies in accurately predicting the heat transfer coefficient between the cold liquid and a warm wall in a low pressure environment. The heat transfer coefficient and the behavior of the liquid is highly dependent on the mass flow rate into the cavity, the cavity wall temperature and the cavity volume. Testing was performed to correlate the modeling performed using Thermal Desktop and Sinda Fluint Thermal and Fluids Analysis Software. This presentation shall describe a methodology to model the cryogenic process using Sinda Fluint, a description of the cryogenic test set up, a description of the test procedure and how the model was correlated to match the test results.

  9. Prediction of electron concentration reductions in re-entry flow fields due to electrophilic liquid and water injection.

    NASA Technical Reports Server (NTRS)

    Pergament, H. S.; Mikatarian, R. R.; Kurzius, S. C.

    1972-01-01

    Discussion of an analytical model which leads to predictions of reductions in electron concentrations in reentry flow fields due to the injection of electrophilic liquids and water. The processes incorporated into the model are: penetration and breakup of the liquid jet, droplet acceleration and vaporization, expansion of the liquid spray due to droplet vaporization, electrophilic vapor diffusion, heterogeneous and homogeneous charged species recombination kinetics and homogeneous electron attachment kinetics. Spray boundary calculations are shown to be in good agreement with photographic observations of water and Freon E-3 sprays in wind tunnel tests of a scale model RAM C-III flight vehicle. Fixed-bias electrostatic probe data taken during the RAM C-III flight are interpreted in terms of effective jet penetration distances - which are shown to be consistent with calculations using the present model.

  10. Modeling of the flow continuum and optimal design of control-oriented injection systems in liquid composite molding processes

    NASA Astrophysics Data System (ADS)

    Gokce, Ali

    Several methodologies are presented in this dissertation that aim to ensure successful filling of the mold cavity consistently, during the mold filling stage of Liquid Composite Molding (LCM) processes such as Resin Transfer Molding (RTM), Vacuum Assisted Resin Transfer Molding (VARTM) and Seemann Composites Resin Infusion Molding (SCRIMP). Key parameters that affect the resin flow in the mold cavity can be divided into two main groups as continuum-related parameters and injection-related parameters. Flow continuum, which consists of all the spaces resin can reach in the mold cavity, has two major components: the porous medium, which is made up of the fiber reinforcements, and the flow channels that are introduced into the flow continuum unintentionally and offer an easy flow path to the resin. The properties that characterize the porous medium and the unintentional flow channels are continuum-related parameters. The injection-related parameters include resin injection locations (gates), resin injection conditions and air drainage locations (vents). Modeling the flow continuum is crucial in predicting the resin flow in the mold cavity. In this study, permeability, the key property of the porous medium, is predicted using the Method of Cells, a proven method to predict macroscopic properties of heterogeneous materials. Unintentional flow channels, which are also called racetracking channels, are modeled using a probabilistic approach. Injection-related parameters are the key tools to influence the resin flow in the mold cavity. In this study, Branch and Bound Search is modified for single gate optimization. Due to its pertinence to injection system design, the parameters that govern gate effectiveness in steering the resin advance are studied. A combinatorial search algorithm is proposed for vent optimization. Vent optimization and gate optimization algorithms are integrated for simultaneous gate and vent optimization. Overall, these methodologies reduce the cycle

  11. Evaluation of a direct injection nebulizer interface for flow injection analysis and high performance liquid chromatography with inductively coupled plasma-atomic emission spectroscopic detection

    SciTech Connect

    LaFreniere, K.E.

    1986-06-01

    A direct injection nebulizer (DIN) was designed, developed, and evaluated to determine its potential utilization as an effective interface for flow injection analysis (FIA) and high performance liquid chromatography (HPLC) coupled with inductively coupled plasma-atomic emission spectroscopic detection. The analytical figures of merit for the DIN when used as an interface for FIA-ICP-AES were found to be comparable to or better than those obtained with conventional pneumatic nebulization in terms of limits of detection (LODs), reproducibility, linearity, and interelement effects. Stable plasma operation was maintained for the DIN sample introduction of a variety of pure organic solvents, including acetonitrile, methanol, methylisobutylketone, and pyridine. The HPLC-DIN-ICP-AES facility was specifically applied for the speciation of inorganic and organometallic species contained in synthetic mixtures, vanilla extracts, and a variety of energy-related materials, such as shale oil process water, coal extracts, shale oil, crude oil, and an SRC II. Suggestions for future research are also considered. 227 refs., 44 figs., 15 tabs.

  12. Two-Phase Model of Liquid-Liquid Interactions With Interface Capturing: Application to Water Assisted Injection Molding

    NASA Astrophysics Data System (ADS)

    Silva, Luisa; Lanrivain, Rodolphe; Zerguine, Walid; Rodriguez-Villa, Andrès; Coupez, Thierry

    2007-05-01

    In this paper, a two phase model to compute liquid-liquid flows is presented. We consider that one phase is a highly viscous thermodependent liquid (polymer phase), whereas the second one is a low viscosity low temperature fluid (water). The first part of this paper concerns capture of the interface between the water and the polymer (or determination of the phase field function). Classical VOF and Level set techniques have been implemented and were ameliorated using mesh adaptation techniques. To accurately determine the velocity field, a two-phase formulation is considered, based in the theory of mixtures, and we introduce a scalar parameter, the phase fraction quantifying the presence of each phase in each point of the computational domain. A friction type coupling between both phases is retained. Using the mixed finite element method within an eulerian framework, we calculate in a single system the whole kinematic variables for both liquids (velocity and pressure of each phase). Results are shown, for 2D and 3D parts.

  13. Liquid sprays and flow studies in the direct-injection diesel engine under motored conditions

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung Lee; Carpenter, Mark H.; Ramos, Juan I.; Schock, Harold J.; Stegeman, James D.

    1988-01-01

    A two dimensional, implicit finite difference method of the control volume variety, a two equation model of turbulence, and a discrete droplet model were used to study the flow field, turbulence levels, fuel penetration, vaporization, and mixing in diesel engine environments. The model was also used to study the effects of engine speed, injection angle, spray cone angle, droplet distribution, and intake swirl angle on the flow field, spray penetration and vaporization, and turbulence in motored two-stroke diesel engines. It is shown that there are optimum conditions for injection, which depend on droplet distribution, swirl, spray cone angle, and injection angle. The optimum conditions result in good spray penetration and vaporization and in good fuel mixing. The calculation presented clearly indicates that internal combustion engine models can be used to assess, at least qualitatively, the effects of injection characteristics and engine operating conditions on the flow field and on the spray penetration and vaporization in diesel engines.

  14. Comparison of ultrasound-induced bioeffects in glass catfish after injection with optison and liquid perflourocarbon droplets

    NASA Astrophysics Data System (ADS)

    Maruvada, Subha; Hynynen, Kullervo

    2003-04-01

    This work is an investigation of ultrasound-induced bioeffects in vivo. Glass catfish were used for these experiments because they are optically transparent. Anaesthetized fish were injected with either optison (OPT) or liquid perflourocarbon droplets (LPD), using microinjection techniques. Shortly after injection, the fish were insonified with one of two single element focused transducers (1.091 MHz and 0.747 MHz). An inverted microscope combined with a digital camera was used to optically monitor ultrasound interaction with the blood vessels in the tail of the fish at 200x magnification. The entire interaction was videotaped and digitized. The fish were insonified at power levels between 1-80 W, which translated into acoustic pressures from 0.45-15 MPa. Sonications were pulsed with burst lengths of 10 ms and 100 ms and a repetition frequency of 1 Hz. The entire length of one sonication at a specific pressure was 20 seconds. The effects of the sonication were analyzed at each pressure level. The ultrasound-induced bioeffects due to OPT and LPD were compared. Threshold values for damage were lower after OPT injection than after LPD injection, especially at lower frequencies.

  15. Injection Characteristics of Non-Swirling and Swirling Annular Liquid Sheets

    NASA Technical Reports Server (NTRS)

    Harper, Brent (Technical Monitor); Ibrahim, E. A.; McKinney, T. R.

    2004-01-01

    A simplified mathematical model, based on body-fitted coordinates, is formulated to study the evolution of non-swirling and swirling liquid sheet emanated from an annular nozzle in a quiescent surrounding medium. The model provides predictions of sheet trajectory, thickness and velocity at various liquid mass flow rates and liquid-swirler angles. It is found that a non-swirling annular sheet converges toward its centerline and assumes a bell shape as it moves downstream from the nozzle. The bell radius, and length are more pronounced at higher liquid mass flow rates. The thickness of the non-swirling annular sheet increases while its stream-wise velocity decreases with an increase in mass flow rate. The introduction of swirl results in the formation of a diverging hollow-cone sheet. The hollow-cone divergence from its centerline is enhanced by an increase in liquid mass flow rate or liquid-swirler angle. The hollow- cone sheet its radius, curvature and stream-wise velocity increase while its thickness and tangential velocity decrease as a result of increasing the mass flow rate or liquid-swirler angle. The present results are compared with previous studies and conclusions are drawn.

  16. Liquid injection field desorption ionization mass spectrometry of cyclic metal carbonyl complexes with tetra-antimony ligands.

    PubMed

    Breunig, Hans J; Linden, H Bernhard; Moldovan, Ovidiu

    2013-01-01

    Reactions of (norbornadiene)Cr(CO)(4) or cis-(piperidine)(2)Mo(CO)(4) with R(2)Sb-SbR(2), and cyclo-(R'Sb)(n) (R' = Et, n-Pr; n = 4, 5) give the complexes cyclo-[M(CO)(4)(R(2)Sb-SbR'- SbR'-SbR(2))] (1: M = Cr, R = Me, R'= Et; 2: M = Mo, R = Et, R' = Et; 3: M = Mo, R = Et, R' = n-Pr). Not accessible to established characterization methods, the oily, extremely reactive unpurified mixture of 3 with scrambled ligands was characterized by mass spectrometry using liquid injection field desorption ionization (LIFDI).

  17. Preparation of nano/macroporous polycaprolactone microspheres for an injectable cell delivery system using room temperature ionic liquid and camphene.

    PubMed

    Kim, Seong Yeol; Hwang, Ji-Young; Shin, Ueon Sang

    2016-03-01

    The nano/macroporous polycaprolactone (PCL) microspheres with cell active surfaces were developed as an injectable cell delivery system. Room temperature ionic liquid (RTIL) and camphene were used as a liquid mold and a porogen, respectively. Various-sized spheres of 244-601μm with pores of various size and shape of 0.02-100μm, were formed depending on the camphene/RTIL ratio (0.8-2.6). To give cell activity, the surface of porous microspheres were further modified with nerve growth factors (NGF) containing gelatin to give a thin NGF/gelatin layer, to which the neural progenitor cells (PC-12) attached and extended their neurites on to the surface layers of the microspheres. The developed microspheres may be potentially applicable as a neuronal cell delivery scaffold for neuron tissue engineering.

  18. Rapid screening of haloacetamides in water using salt-assisted liquid-liquid extraction coupled injection-port silylation gas chromatography-mass spectrometry.

    PubMed

    Chen, Tzu-Ling; Tzing, Shin-Hwa; Ding, Wang-Hsien

    2015-11-27

    The rapid screening of trace amounts of the nitrogenous disinfection by-products, haloacetamides (HAcAms), in drinking and swimming pool water was performed by a simple and reliable procedure based on salt-assisted liquid-liquid extraction (SALLE) combined with injection-port silylation gas chromatography-mass spectrometry (IPS-GC-MS) method. The optimal SALLE conditions involved the injection of 4-mL of ethyl acetate into a 10-mL water sample (pH 7) containing 3-g of sodium sulfate. After vortex extraction for 1min and centrifugation, 10μL of the extract (mixed with 1μL of MTBSTFA) was directly determined by IPS-GC-MS. The limits of quantitation (LOQs) were determined to be 0.03-0.3μg/L. Precision, as indicated by relative standard deviations (RSDs), was less than 10% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 76% and 94%. The SALLE plus IPS-GC-MS was successfully applied to quantitatively determine HAcAms from drinking and swimming pool water samples, and the total concentrations of the compounds ranged from 0.43 to 4.03μg/L.

  19. A fully automated effervescence assisted dispersive liquid-liquid microextraction based on a stepwise injection system. Determination of antipyrine in saliva samples.

    PubMed

    Medinskaia, Kseniia; Vakh, Christina; Aseeva, Darina; Andruch, Vasil; Moskvin, Leonid; Bulatov, Andrey

    2016-01-01

    A first attempt to automate the effervescence assisted dispersive liquid-liquid microextraction (EA-DLLME) has been reported. The method is based on the aspiration of a sample and all required aqueous reagents into the stepwise injection analysis (SWIA) manifold, followed by simultaneous counterflow injection of the extraction solvent (dichloromethane), the mixture of the effervescence agent (0.5 mol L(-1) Na2CO3) and the proton donor solution (1 mol L(-1) CH3COOH). Formation of carbon dioxide microbubbles generated in situ leads to the dispersion of the extraction solvent in the whole aqueous sample and extraction of the analyte into organic phase. Unlike the conventional DLLME, in the case of EA-DLLME, the addition of dispersive solvent, as well as, time consuming centrifugation step for disruption of the cloudy state is avoided. The phase separation was achieved by gentle bubbling of nitrogen stream (2 mL min(-1) during 2 min). The performance of the suggested approach is demonstrated by determination of antipyrine in saliva samples. The procedure is based on the derivatization of antipyrine by nitrite-ion followed by EA-DLLME of 4-nitrosoantipyrine and subsequent UV-Vis detection using SWIA manifold. The absorbance of the yellow-colored extract at the wavelength of 345 nm obeys Beer's law in the range of 1.5-100 µmol L(-1) of antipyrine in saliva. The LOD, calculated from a blank test based on 3σ, was 0.5 µmol L(-1).

  20. Gas phase depletion and flow dynamics in horizontal MOCVD reactors

    NASA Astrophysics Data System (ADS)

    Van de Ven, J.; Rutten, G. M. J.; Raaijmakers, M. J.; Giling, L. J.

    1986-08-01

    Growth rates of GaAs in the MOCVD process have been studied as a function of both lateral and axial position in horizontal reactor cells with rectangular cross-sections. A model to describe growth rates in laminar flow systems on the basis of concentration profiles under diffusion controlled conditions has been developed. The derivation of the growth rate equations includes the definition of an entrance length for the concentration profile to developed. In this region, growth rates appear to decrease with the 1/3 power of the axial position. Beyond this region, an exponential decrease is found. For low Rayleigh number conditions, the present experimental results show a very satisfactory agreement with the model without parameter fitting for both rectangular and tapered cells, and with both H 2 and N 2 as carrier gases. Theory also predicts that uniform deposition can be obtained over large areas in the flow direction for tapered cells, which has indeed been achieved experimentally. The influence of top-cooling in the present MOCVD system has been considered in more detail. From the experimental results, conclusions could be drawn concerning the flow characteristics. For low Rayleigh numbers (present study ≲ 700) it follows that growth rate distributions correspond with forced laminar flow characteristics. For relatively high Rayleigh numbers (present work 1700-2800), free convective effects with vortex formation are important. These conclusions are not specific for the present system, but apply to horizontal cold-wall reactors in general. On the basis of the present observations, recommendations for a cell design to obtain large area homogeneous deposition have been formulated. In addition, this work supports the conclusion that the final decomposition of trimethylgallium in the MOCVD process mainly takes place at the hot substrate and susceptor and not in the gas phase.

  1. Transport phenomena and the effects of reactor geometry for epitaxial GaN growth in a vertical MOCVD reactor

    NASA Astrophysics Data System (ADS)

    Tseng, Chien-Fu; Tsai, Tsung-Yen; Huang, Yen-Hsiu; Lee, Ming-Tsang; Horng, Ray-Hua

    2015-12-01

    In this study a numerical simulation was carried out to analyze the transport phenomena in a vertical type metal organic chemical vapor deposition (MOCVD) reactor for Gallium Nitride (GaN) growth. The simulated results were compared and validated by experiment. The effects of showerhead design and chamber height are investigated and discussed. It was found that, by properly adjusting the height of the chamber, both the growth rate and film uniformity could be significantly improved. This is attributed to the suppression of the thermal and mass transfer boundary layers by the injection flow of reacting gas mixtures, as well as the confined vertical vortices caused by the geometry of the reduced space. However, inappropriate design of the distance between the showerhead and the susceptor can result in uneven distribution of the organic source in the vicinity of the substrate surface resulting in an uneven growth rate of the GaN film. Consequently, there exists an optimal chamber height that will give the best growth rate and uniformity to the GaN film as discussed in this study. This study provides comprehensive insight into the transport phenomena of GaN growth that includes coupled heat and mass transfer as well as chemical reactions. The results provide important information in a succinct format and enable decisions to be made about the showerhead and the geometrical design and size of a vertical MOCVD reactor.

  2. Electrical properties of ferroelectric-gate FETs with SrBi2Ta2O9 formed using MOCVD technique

    NASA Astrophysics Data System (ADS)

    Yan, Kang; Takahashi, Mitsue; Sakai, Shigeki

    2012-09-01

    Ferroelectric-gate field-effect transistors (FeFETs) with a Pt/SrBi2Ta2O9/Hf-Al-O/Si gate stack were fabricated using the metal-organic chemical vapor deposition (MOCVD) technique to prepare the SrBi2Ta2O9 (SBT) ferroelectric layer. A good threshold voltage ( V th) distribution was found for more than 90 n-channel FeFETs in one chip with a 170 nm SBT layer owing to the good film uniformity of the SBT layer deposited by MOCVD. The average memory window (Vw^{av}) and the standard deviations ( σ thl, σ thr) of the left- and right-side branches of the drain-gate voltage curves of the FeFETs yielded a Vw^{av}/(σ_{thl} + σ_{thr}) value of 5.45, indicating that the FeFETs can be adapted for large-scale-integration. The electric field, the energy band profile in the gate stack, and the gate leakage current were also investigated at high gate voltages. We found that the effect of Fowler-Nordheim tunneling appeared under these conditions. Because of the tunneling injection and trapping of electrons into the gate insulators, the operation voltage ranges of the FeFETs were limited by this tunneling.

  3. Semiconductor Laser Diode Arrays by MOCVD (Metalorganic Chemical Vapor Deposition)

    DTIC Science & Technology

    1987-09-01

    Roberts. N. J1. Mason. and M. Robinson, J. Cryst. Growth 68, 422 (1984). ’M. R. Leys. C. van Opdorp. M. P. A. .’iegers, and H. J. Talen -van der Mheen...geometry effects is and superlattices has been dominated obtained by including one measured by the MOCVD growth technology . data point in the analysis...Dapkus, Gallium : Arsenide Technology , D.K. Ferry, Ed., tices i Howard W. Sams and Co., Indianapolis, hetero- 1985, p. 79. s is nec- G . 4. G. Costrini and

  4. Fluoxetine and norfluoxetine analysis by direct injection of human plasma in a column switching liquid chromatographic system.

    PubMed

    Santos-Neto, Alvaro J; Fernandes, Christian; Rodrigues, José C; Alves, Claudete; Lanças, Fernando M

    2008-01-01

    A column switching LC method is presented for the analysis of fluoxetine (FLU) and norfluoxetine (NFLU) by direct injection of human plasma using a lab-made restricted access media (RAM) column. A RAM-BSA-octadecyl silica (C-18) column (40 mm x 4.6 mm, 10 microm) is evaluated in both backflush and foreflush elution modes and coupled with a C-18 lab-made (50 mm x 4.6 mm, 3 microm) analytical column in order to perform online sample preparation. Direct injection of 100 microL of plasma samples is possible with the developed approach. In addition, reduction of sample handling is obtained when compared with traditional liquid-liquid extraction (LLE) and SPE. The total analysis time is around 20 min. A LOQ of 15 ng/mL is achieved in a concentration range of 15-500 ng/mL, allowing the therapeutic drug monitoring of clinical samples. The precision values achieved are lower than 15% for all the evaluated points with adequate recovery and accuracy. Furthermore, no matrix interferences are found in the analysis and the proposed method shows to be an adequate alternative for analysis of FLU in plasma.

  5. Preliminary Investigation of Stagnation Point Liquid Injection Influence on Blunt Body Aerodynamics

    NASA Technical Reports Server (NTRS)

    Woods, William C.; Jones, Kenneth M.; Genzel, Noah N.

    2002-01-01

    A preliminary investigation has been performed to determine the influence of stagnation point water injection on the hypersonic aerodynamic forces and moments for two-dimensional blunt bodies. This investigation was performed in the Langley 20-Inch Mach 6 Air Tunnel, and represents the qualitative first phase of a study to examine the potential benefits of water injection to reduce aerodynamic drag and aero-heating. Tests with a 4-inch diameter hemisphere cylinder and a 4-inch diameter cylinder with a span 1.5 times the diameter were performed over a range of free-stream unit Reynolds number from two million to six million per ft and of angle of attack (-5 deg to 5 deg) with water and gaseous nitrogen injection at the geometric stagnation point. The momentum flux ratio, that is, the ratio of the momentum flux of the jet to that of the free-stream flow, was varied from the non-blowing value of zero up to 0.00031 by maintaining the jet momentum fixed and varying the free-stream momentum, hence Reynolds number. The effect of water injection on the aerodynamic drag coefficient for the hemisphere cylinder was observed to be negligible as the momentum flux ratio was increased to 0.00017, but decreased significantly as this ratio increased above 0.00017; a nearly 50 percent reduction in drag occurred for a factor of two increase in momentum flux ratio.

  6. Panitumumab Injection

    MedlinePlus

    ... as a solution (liquid) to be given by infusion (injected into a vein). It is usually given ... doctor or nurse in a doctor's office or infusion center. Panitumumab is usually given once every 2 ...

  7. Suppression of Mg propagation into subsequent layers grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Agarwal, Anchal; Tahhan, Maher; Mates, Tom; Keller, Stacia; Mishra, Umesh

    2017-01-01

    Low temperature (LT) flow modulation epitaxy (FME) or "pulsed" growth was successfully used to prevent magnesium from Metalorganic Chemical Vapor Deposition (MOCVD) grown p-GaN:Mg layers riding into subsequently deposited n-type layers. Mg concentration in the subsequent layers was lowered from ˜1 × 1018 cm-3 for a medium temperature growth at 950 °C to ˜1 × 1016 cm-3 for a low temperature growth at 700 °C via FME. The slope of the Mg concentration drop in the 700 °C FME sample was 20 nm/dec—the lowest ever demonstrated by MOCVD. For growth on Mg implanted GaN layers, the drop for a medium temperature regrowth at 950 °C was ˜10 nm/dec compared to >120 nm/dec for a high temperature regrowth at 1150 °C. This drop-rate obtained at 950 °C or lower was maintained even when the growth temperature in the following layers was raised to 1150 °C. A controlled silicon doping series using LT FME was also demonstrated with the lowest and highest achieved doping levels being 5 × 1016 cm-3 and 6 × 1019 cm-3, respectively.

  8. MOCVD growth of vertically aligned InGaN nanowires

    NASA Astrophysics Data System (ADS)

    Kuo, H. C.; Su Oh, Tae; Ku, P.-C.

    2013-05-01

    In this work, we report the growth of vertically aligned bulk InGaN nanowires (NWs) on r-plane sapphire substrate by metal organic chemical vapor deposition (MOCVD). Through the optimization process of growth conditions, such as growth temperature and pressure, we obtained high density InGaN NWs consisting of one (0001) polar- and two equivalent {1101} semi-polar planes. We have shown the highest InGaN NWs wire density of 8×108 cm-2,with an average diameter of 300 nm and a length of 2 μm. From results of photoluminescence (PL) at 30 K and 300 K, we observed the intense and broad emission peak from InGaN NWs at around 595 nm, and confirmed that the luminescence could be tuned from 580 nm to 660 nm by controlling the indium flow (TMIn) rate. Our results indicate that MOCVD-grown InGaN NWs can be effective absorbers of the blue-green range of solar spectrum and may be one of the good candidates for high efficiency photovoltaic devices targeting at blue-green photons.

  9. Electro-optic materials by solid source MOCVD

    SciTech Connect

    Hiskes, R.; Dicarolis, S.A.; Fouquet, J.; Lu, Z.; Feigelson, R.S.; Route, R.K.; Leplingard, F.; Foster, C.M.

    1993-12-01

    The solid source MOCVD technique, employing a single powder vaporization source composed of mixed beta-diketonate metalorganic compounds, has been used to grow thin films of a variety of electro-optic materials, including lithium niobate, strontium barium niobate, and potassium niobate. Preliminary results for potassium niobate films indicate that a volatile potassium organometallic source can be synthesized useful for growing potassium niobate by MOCVD. High single phase (001) oriented strontium barium niobate films have been deposited which exhibit waveguiding behavior. The most extensive work has been done on lithium niobate deposited epitaxially on a variety of substrates. Oriented z-axis (001) films have been grown on c-axis sapphire with and without a (111) oriented platinum base electrode and on a bulk grown lithium niobate substrate. Films grown directly on c-axis sapphire at 700 C exhibit x-ray rocking curve linewidths as low as .044 degrees, nearly perfect in-plane orientation as determined by x-ray phi scans, and peak-to-peak surface roughness less than 40 {Angstrom}. Optical waveguiding has been demonstrated by single prism coupling technique on similar films 1175--2000 {Angstrom} thick grown at 500 C, with optical losses of approximately 2 db/cm at 632.8 nm measured over 3.5 cm long films. Polarization vs. electric field measurements on 1100 {Angstrom} thick films grown on platinum show a hysteresis loop indicating ferroelectric behavior.

  10. Simulation of elution profiles in liquid chromatography-I: Gradient elution conditions, and with mismatched injection and mobile phase solvents.

    PubMed

    Jeong, Lena N; Sajulga, Ray; Forte, Steven G; Stoll, Dwight R; Rutan, Sarah C

    2016-07-29

    High-performance liquid chromatography (HPLC) simulators are effective method development tools. The goal of the present work was to design and implement a simple algorithm for simulation of liquid chromatographic separations that allows for characterization of the effect of injection solvent mismatch and injection solvent volume overload. The simulations yield full analyte profiles during solute migration and at elution, which enable a thorough physical understanding of the effects of method variables on chromatographic performance. The Craig counter-current distribution model (the plate model) is used as the basis for simulation, where a local retention factor is assigned for each spatial and temporal element within the simulation. The algorithm, which is an adaptation of an approach originally described by Czok and Guiochon (Ref. [10]), is sufficiently flexible to allow the use of either linear (e.g., Linear Solvent Strength Theory) or non-linear models of solute retention (e.g., Neue-Kuss (Ref. [36])). In this study, both types of models were used, one for simulating separations of a homologous series of alkylbenzenes, and the other for separations of selected amphetamines. The simulation program was validated first by comparison of simulated retention times and peak widths for five amphetamines to predictions obtained using linear solvent strength (LSS) theory, and to results from experimental separations of these compounds. The simulated retention times for the amphetamines agreed within 0.02% and 2.5% compared to theory and experiment, respectively. Secondly, the program was evaluated for simulating the case where there is a compositional mismatch between the mobile phase at the column inlet and the injection solvent (i.e., the sample matrix). This work involved alkylbenzenes, and retention time and peak width predictions from simulations were within 1.5 and 6.0% of experimental values, respectively, even without correction for extra-column dispersion. The

  11. Dispersive liquid-liquid microextraction for the determination of phenols by acetonitrile stacking coupled with sweeping-micellar electrokinetic chromatography with large-volume injection.

    PubMed

    He, Hui; Liu, Shuhui; Meng, Zhaofu; Hu, Shibing

    2014-09-26

    The current routes to couple dispersive liquid-liquid microextraction (DLLME) with capillary electrophoresis (CE) are evaporation of water immiscible extractants and backextraction of analytes. The former is not applicable to extractants with high boiling points, the latter being effective only for acidic or basic analytes, both of which limit the further application of DLLME-CE. In this study, with 1-octanol as a model DLLME extractant and six phenols as model analytes, a novel method based on acetonitrile stacking and sweeping is proposed to accomplish large-volume injection of 1-octanol diluted with a solvent-saline mixture before micellar electrokinetic chromatography. Brij-35 and β-cyclodextrin were employed as pseudostationary phases for sweeping and also for improving the compatibility of sample zone and aqueous running buffer. A short solvent-saline plug was used to offset the adverse effect of the water immiscible extractant on focusing efficiency. The key parameters affecting separation and concentration were systematically optimized; the effect of Brij-35 and 1-octanol on focusing mechanism was discussed. Under the optimized conditions, with ∼ 30-fold concentration enrichment by DLLME, the diluted extractant (8×) was then injected into the capillary with a length of 21 cm (42% of the total length), which yielded the overall improvements in sensitivity of 170-460. Limits of detection and qualification ranged from 0.2 to 1.0 ng/mL and 1.0 to 3.4 g/mL, respectively. Acceptable repeatability lower than 3.0% for migration time and 9.0% for peak areas were obtained. The developed method was successfully applied for analysis of the phenol pollutants in real water samples.

  12. Determination of rare earth elements in geological samples by inductively coupled plasma atomic emission spectrometry with flow injection liquid-liquid extraction.

    PubMed

    Xu, Zhifang; Liu, Congqiang; Zhang, Hongxiang; Ma, Yingjun; Lin, Soulin

    2003-12-01

    A direct sampling with organic solvent extracts for simultaneous multi-element determination implemented with inductively coupled plasma atomic emission spectrometry (ICP-AES) associated with a flow injection liquid-liquid extraction (FI-LLE) sample preconcentration method was studied. The "robustness" of the plasma discharge with tributyl phosphate (TBP) loading was diagnosed by using the Mg II 279.55 nm and Mg I 285.21 nm lines intensity ratio. A FI-LLE preconcentration system for rare earth elements (REEs)-nitrate-TBP was established by using a laboratory-designed phase separator. For these elements, an average sensitivity enhancement factor of 64 was obtained with respect to ICP-AES sampling with aqueous solutions. The precision of the method was characterized by a relative standard deviation (%RSD) of 1.8 - 5.2%. A throughput of 27 samples per hour can be achieved with an organic solvent consumption of less than 200 microl per determination. Good results were obtained for the analysis of standard reference materials.

  13. Separation/preconcentration and determination of quercetin in food samples by dispersive liquid-liquid microextraction based on solidification of floating organic drop -flow injection spectrophotometry.

    PubMed

    Asadollahi, Tahereh; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Amirkavei, Mooud

    2015-02-01

    A new dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFOD)-flow injection spectrophotometry (FI) method for the separation and preconcentration of trace amounts of quercetin was developed. 1-Undecanol and methanol was used as the extraction and disperser solvent, respectively. The factors influencing the extraction by DLLME-SFOD such as the volume of the extraction and disperser solvents, pH and concentration of salt were optimized. The optimal conditions were found to be; volume of the extraction solvent, 80 μL; the volume of the disperser solvent, 100 μL; and the pH of the sample, 3. The linear dynamic range and detection limit were 5.0 × 10(-8)-5.0 × 10(-7) mol L(-1) and 1 × 10(-8) mol L(-1), respectively. The relative standard deviation (R.S.D.) at 6.1 × 10(-8) mol L(-1) level of quercetin (n = 10) was found to be 2.8 %. The method was successfully applied to the determination of quercetin in the apple, grape, onion and tomato samples. Figureᅟ

  14. Determination of nifuroxazide in biological fluids by automated high-performance liquid chromatography with large-volume injection.

    PubMed

    Guinebault, P R; Broquaire, M; Braithwaite, R A

    1981-01-16

    A high-performance liquid chromatographic method for the measurement of nifuroxazide in plasma is described. The technique is based on the single extraction of the drug from buffered plasma with chloroform, using nifuratel as internal standard. The chromatographic system consisted of a 15 cm x 4.6 mm I.D. stainless-steel column packed with Spherisorb ODS, 5 micrometer, and the mobile phase was acetonitrile-orthophosphoric acid (pH 2.5) (30:70). The method was able to measure accurately plasma nifuroxazide concentrations down to 2 ng . ml-1 using 2 ml of sample with no interference from endogenous compounds. The coefficients of variation of the method at 200 and 2 ng . ml-1 were 3% and 15%, respectively, and the calibration graph was linear in this range. The use of automatic injection makes the method suitable for the routine analysis of large numbers of samples.

  15. Intelligent foreign particle inspection machine for injection liquid examination based on modified pulse-coupled neural networks.

    PubMed

    Ge, Ji; Wang, Yaonan; Zhou, Bowen; Zhang, Hui

    2009-01-01

    A biologically inspired spiking neural network model, called pulse-coupled neural networks (PCNN), has been applied in an automatic inspection machine to detect visible foreign particles intermingled in glucose or sodium chloride injection liquids. Proper mechanisms and improved spin/stop techniques are proposed to avoid the appearance of air bubbles, which increases the algorithms' complexity. Modified PCNN is adopted to segment the difference images, judging the existence of foreign particles according to the continuity and smoothness properties of their moving traces. Preliminarily experimental results indicate that the inspection machine can detect the visible foreign particles effectively and the detection speed, accuracy and correct detection rate also satisfying the needs of medicine preparation.

  16. Liquid Injection Field Desorption Ionization Mass Spectrometry of Cyclic Metal Carbonyl Complexes with Tetra-Antimony Ligands

    NASA Astrophysics Data System (ADS)

    Breunig, Hans J.; Linden, H. Bernhard; Moldovan, Ovidiu

    2013-01-01

    Reactions of (norbornadiene)Cr(CO)4 or cis-(piperidine)2Mo(CO)4 with R2Sb-SbR2, and cyclo-(R'Sb)n (R' = Et, n-Pr; n = 4, 5) give the complexes cyclo-[M(CO)4(R2Sb-SbR'- SbR'-SbR2)] ( 1: M = Cr, R = Me, R'= Et; 2: M = Mo, R = Et, R' = Et; 3: M = Mo, R = Et, R' = n-Pr). Not accessible to established characterization methods, the oily, extremely reactive unpurified mixture of 3 with scrambled ligands was characterized by mass spectrometry using liquid injection field desorption ionization (LIFDI). [Figure not available: see fulltext.

  17. Intelligent Foreign Particle Inspection Machine for Injection Liquid Examination Based on Modified Pulse-Coupled Neural Networks

    PubMed Central

    Ge, Ji; Wang, YaoNan; Zhou, BoWen; Zhang, Hui

    2009-01-01

    A biologically inspired spiking neural network model, called pulse-coupled neural networks (PCNN), has been applied in an automatic inspection machine to detect visible foreign particles intermingled in glucose or sodium chloride injection liquids. Proper mechanisms and improved spin/stop techniques are proposed to avoid the appearance of air bubbles, which increases the algorithms' complexity. Modified PCNN is adopted to segment the difference images, judging the existence of foreign particles according to the continuity and smoothness properties of their moving traces. Preliminarily experimental results indicate that the inspection machine can detect the visible foreign particles effectively and the detection speed, accuracy and correct detection rate also satisfying the needs of medicine preparation. PMID:22412318

  18. Exogenous factors contributing to column bed heterogeneity: Part 1: Consequences of 'air' injections in liquid chromatography.

    PubMed

    Samuelsson, Jörgen; Fornstedt, Torgny; Shalliker, Andrew

    2015-08-07

    It has been shown that not only the packing homogeneity, but also factors external to the column bed, such as, frits and distributors can have important effects on the column performance. This current communication is the first in a series focusing on the impact of exogenous factors on the column bed heterogeneity. This study is based on several observations by us and others that chromatographic runs often, for technical reasons, include more or less portions of air in the injections. It is therefore extremely important to find out the impact of air on the column performance, the reliability of the results derived from analyses where air was injected, and the effect on the column homogeneity. We used a photographic approach for visualising the air transport phenomena, and found that the air transport through the column is comprised of many different types of transport phenomena, such as laminal flow, viscous fingering like flows, channels and bulbs, and pulsations. More particularly, the air clouds within the column definitely interact in the adsorption, i.e. mobile phase adsorbed to the column surface is displaced. In addition, irrespective of the type of air transport phenomena, the air does not penetrate the column homogeneously. This process is strongly flow dependent. In this work we study air transport both in an analytical scale and a semi-prep column.

  19. Novel cation selective exhaustive injection-sweeping procedure for 5-nitroimidazole determination in waters by micellar electrokinetic chromatography using dispersive liquid-liquid microextraction.

    PubMed

    Hernández-Mesa, Maykel; Airado-Rodríguez, Diego; Cruces-Blanco, Carmen; García-Campaña, Ana M

    2014-05-09

    A novel method consisting of cation-selective exhaustive injection and sweeping (CSEI-sweeping) as on-line preconcentration followed by a micellar electrokinetic chromatography (MEKC) separation has been developed for the determination of 5-nitroimidazoles (5-NDZ) in environmental waters. Moreover, dispersive liquid-liquid microextraction (DLLME) has been proposed for first time as sample treatment technique prior to CSEI-sweeping-MEKC. DLLME was applied to 5mL of sample. Dibromomethane (1156μL) and 2-butanol (1363μL) were employed as extractant and dispersive solvents, respectively. Salting-out effect was achieved by the addition of 16% (w/v) NaCl to the samples. After DLLME and organic solvent evaporation, the residue was redissolved in a low conductivity solvent (5mM phosphoric acid with 5% of methanol) and electrokinetically injected at 9.8kV for 632s in a bare fused-silica capillary (57.2cm, 50μm I.D.). Prior to the injection, the capillary was rinsed with 50mM phosphate buffer pH 2.5, followed by a plug of a higher conductivity buffer (100mM phosphate pH 2.5, 50mbar, 264s) and a plug of water (50mbar, 2s). Separation was carried out applying -30kV at 20°C in 44mM phosphate buffer pH 2.5, containing 8% tetrahydrofuran and 123mM sodium dodecyl sulfate. Analytical signals were monitored at 276nm. Validation was performed in river and well waters, obtaining satisfactory results in terms of linearity, precision (% RSD generally lower than 10%) and trueness (recoveries higher than 70% in almost all cases). LODs ranged from 0.61 to 2.44ng/mL. The combination of this microextraction technique with the proposed capillary electrophoresis methodology supposes a simple, sensitive and cheap alternative for 5-NDZ analyses, in accordance with the aims of green chemistry.

  20. Direct and comprehensive analysis of ginsenosides and diterpene alkaloids in Shenfu injection by combinatory liquid chromatography-mass spectrometric techniques.

    PubMed

    Yang, Hua; Liu, Lei; Gao, Wen; Liu, Ke; Qi, Lian-Wen; Li, Ping

    2014-04-01

    Shenfu injection (SFI) is a widely used Chinese herbal formulation for cardiac diseases prepared from red ginseng and processed aconite root. Clinical observations and pharmacological effects on SFI have been well investigated. Chemical analysis and quality control studies of this formulation, however, are relatively limited, especially regarding toxic aconite alkaloids. In this work, a high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF MS) method was applied to comprehensive analysis of constituents in SFI. Highly sensitive MS allows direct analysis of injections without additional sample pretreatment required. Using diagnostic ions and fragmentation rules, we identified 23 trace diterpene alkaloids, nineteen ginseng saponins, one panaxytriol, and one 5-hydroxymethylfurfural in SFI. A LC-MS method with selected ion monitoring was then used to quantify 24 major alkaloids and ginsenosides. The method was validated in terms of linearity, accuracy and precision. Especially, the limits of quantification were low to 0.4-18ng/mL for diterpene alkaloids. The total concentrations of saponins and alkaloids were about 676-742μg/mL and 3-7μg/mL in five batches of SFI samples, respectively. Finally, cosine ratio and euclidean distance were introduced to evaluate the batch-to-batch reproducibility of SFI samples, and the results demonstrated high quality consistency. Global identification and quantification of complex constituents based on LC-MS promises wide applications in quality control and batch monitoring for herbal products.

  1. Quantitative determination of cyclic polylactic acid oligomers in serum by direct injection liquid chromatography tandem mass spectrometry.

    PubMed

    Osaka, Issey; Yoshimoto, Arihumi; Watanabe, Mikio; Takama, Masashi; Murakami, Masahiro; Kawasaki, Hideya; Arakawa, Ryuichi

    2008-07-15

    Polylactic acid (PLA) is a biodegradable polymer, currently used in pharmaceutical and surgical devices. There is a concern that cyclic polylactic acid (CPLA), which is a by-product of PLA synthesis, may be introduced into the human body as an undesirable contaminant. We carried out a quantitation investigation of the CPLA heptamer (CPLA-7) by liquid chromatography mass spectrometry (LC-MS). We found that CPLA-7 binds strongly with serum proteins and that only 62% of CPLA-7 was recovered after routine deproteination; therefore, we directly injected serum into the LC-MS/MS system after passage through a bovine serum albumin (BSA)-coated chromatographic column and found the recovery of CPLA-7 was improved to 84%, and that the detection (S/N=3) and quantitation limit (S/N=10 and below 15% relative standard deviation) were 1.5 and 2.5 ng/mL, respectively. We conclude that direct injection LC-MS/MS, using a BSA column, is a simple and effective quantitative analysis method for CPLA in serum.

  2. WETTABILITY ALTERATION OF POROUS MEDIA TO GAS-WETTING FOR IMPROVING PRODUCTIVITY AND INJECTIVITY IN GAS-LIQUID FLOWS

    SciTech Connect

    Abbas Firoozabadi

    2003-12-01

    Wettability alteration to intermediate gas-wetting in porous media by treatment with FC-759, a fluoropolymer polymer, has been studied experimentally. Berea sandstone was used as the main rock sample in our work and its wettability before and after chemical treatment was studied at various temperatures from 25 to 93 C. We also studied recovery performance for both gas/oil and oil/water systems for Berea sandstone before and after wettability alteration by chemical treatment. Our experimental study shows that chemical treatment with FC-759 can result in: (1) wettability alteration from strong liquid-wetting to stable intermediate gas-wetting at room temperature and at elevated temperatures; (2) neutral wetting for gas, oil, and water phases in two-phase flow; (3) significant increase in oil mobility for gas/oil system; and (4) improved recovery behavior for both gas/oil and oil/water systems. This work reveals a potential for field application for improved gas-well deliverability and well injectivity by altering the rock wettability around wellbore in gas condensate reservoirs from strong liquid-wetting to intermediate gas-wetting.

  3. MOCVD growth of AlGaN UV LEDs

    SciTech Connect

    Han, J.; Crawford, M.H.

    1998-09-01

    Issues related to the MOCVD growth of AlGaN, specifically the gas-phase parasitic reactions among TMG, TMA, and NH{sub 3}, are studied using an in-situ optical reflectometer. It is observed that the presence of the well-known gas phase adduct (TMA: NH{sub 3}) could seriously hinder the incorporation behavior of TMGa. Relatively low reactor pressures (30--50 Torr) are employed to grow an AlGaN/GaN SCH QW p-n diode structure. The UV emission at 360 nm (FWHM {approximately} 10 nm) represents the first report of LED operation from an indium-free GaN QW diode.

  4. MOCVD manifold switching effects on growth and characterization

    NASA Technical Reports Server (NTRS)

    Clark, Ivan O.; Fripp, Archibald L.; Jesser, William A.

    1991-01-01

    A combined modeling and experimental approach is used to quantify the effects of various manifold components on the switching speed in metalorganic chemical vapor deposition (MOCVD). In particular, two alternative vent-run high-speed switching manifold designs suitable for either continuous or interrupted growth have been investigated. Both designs are incorporated in a common manifold, instrumented with a mass spectrometer. The experiments have been performed using nitrogen as the transport gas and argon as the simulated source gas. The advantages and limitations of two designs are discussed. It is found that while constant flow manifold switching systems may have fluid dynamic advantages, care must be taken to minimize sections of the supply manifold with low flow rates if rapid changes in alloy composition are required.

  5. AlGaInN quaternary alloys by MOCVD

    SciTech Connect

    McIntosh, F.G.; Piner, E.; Boutros, K.; Roberts, J.C.; He, Y.; El-Masry, N.; Bedair, S.M.; Moussa, M.

    1996-11-01

    AlGaInN quaternary alloy based devices can cover the emission wavelength from deep UV to red. This quaternary alloy also offers lattice matched heterostructures for both optical and microwave devices. The authors report on the MOCVD growth of Al{sub x}Ga{sub 1{minus}x{minus}y}In{sub y}N (0 < x < 0.12), (0 < y < 0.15) at 750 C on sapphire substrates, using TMG, EDMIn, TMAl and NH{sub 3} precursors. Chemical composition, lattice constants and bandgaps of the grown films were determined by EDS, X-ray diffraction and room temperature PL. Data indicates that the lattice constants can also be deduced using Vegard`s law, indicating a solid solution of this alloy. PL showed band edge emission, however emission from deep levels was also observed. Optimized growth conditions and heterostructures using this quaternary alloy will be presented.

  6. Optimization of GaN thin films via MOCVD

    NASA Technical Reports Server (NTRS)

    Dickens, Corey; Wilson, Sylvia L.

    1995-01-01

    A unique characteristic of every semiconductor is the amount of energy required to break an electron bond in the lowest band of allowed states, the valence band. The energy necessary to set an electron free and allow it to conduct in the material is termed the energy gap (Eg). Semiconductors with wide bandgap energies have been shown to possess properties for high power, high temperature, radiation resistance damage, and short wavelength optoelectronic applications. Gallium nitride, which has a wide gap of 3.39 eV, is a material that has demonstrated these characteristics. Various growth conditions are being investigated for quality gallium nitride heteroepitaxy growth via the technique of low pressure metal organic chemical vapor deposition (MOCVD) that can be used for device development.

  7. Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.

    PubMed

    Li, Pingjing; Zhang, Xing; Hu, Bin

    2011-12-30

    In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 μL of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples.

  8. The biocompatibility of titanium in a buffer solution: compared effects of a thin film of TiO2 deposited by MOCVD and of collagen deposited from a gel.

    PubMed

    Popescu, Simona; Demetrescu, Ioana; Sarantopoulos, Christos; Gleizes, Alain N; Iordachescu, Dana

    2007-10-01

    This study aims at evaluating the biocompatibility of titanium surfaces modified according two different ways: (i) deposition of a bio-inert, thin film of rutile TiO(2) by chemical vapour deposition (MOCVD), and (ii) biochemical treatment with collagen gel, in order to obtain a bio-interactive coating. Behind the comparison is the idea that either the bio-inert or the bio-active coating has specific advantages when applied to implant treatment, such as the low price of the collagen treatment for instance. The stability in buffer solution was evaluated by open circuit potential (OCP) for medium time and cyclic voltametry. The OCP stabilized after 5.10(4) min for all the specimens except the collagen treated sample which presented a stable OCP from the first minutes. MOCVD treated samples stabilized to more electropositive values. Numeric results were statistically analysed to obtain the regression equations for long time predictable evolution. The corrosion parameters determined from cyclic curves revealed that the MOCVD treatment is an efficient way to improve corrosion resistance. Human dermal fibroblasts were selected for cell culture tests, taking into account that these cells are present in all bio-interfaces, being the main cellular type of connective tissue. The cells grew on either type of surface without phenotype modification. From the reduction of yellow, water-soluble 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT cytotoxicity test), MOCVD treated samples offer better viability than mechanically polished Ti and collagen treated samples as well. Cell spreading, as evaluated from microscope images processed by the program Sigma Scan, showed also enhancement upon surface modification. Depending on the experimental conditions, MOCVD deposited TiO(2) exhibits different nanostructures that may influence biological behaviour. The results demonstrate the capacity of integration in simulated physiologic liquids for an implant pretreated by

  9. Membrane supported liquid-liquid-liquid microextraction combined with field-amplified sample injection CE-UV for high-sensitivity analysis of six cardiovascular drugs in human urine sample.

    PubMed

    Zhou, Xiaoqing; He, Man; Chen, Beibei; Yang, Qing; Hu, Bin

    2016-05-01

    An effective dual preconcentration method involving off-line membrane supported liquid-liquid-liquid microextraction (MS-LLLME) and on-line field-amplified sample injection (FASI) was proposed for the extraction of six cardiovascular drugs, including mexiletine, xylocaine, propafenone, propranolol, metoprolol, and carvedilol from aqueous solution prior to CE-UV. In MS-LLLME, the analytes were extracted from 9 mL sample solution into toluene, and then back extracted into a drop of acceptor phase of 10 μL 20 mmol/L acetic acid. After that, the acceptor phase was directly introduced into CE for FASI without any modification. In FASI process, water plug was hydrodynamically injected (50 mbar, 3 s) into the capillary prior to sample injection (+6 kV, 18 s). Six target analytes were separated in less than 10 min at 25°C with a BGE consisting of 70 mmol/L Tris-H3 PO4 (pH 2.2) containing 10% v/v methanol. Under the optimized conditions, LODs obtained by the proposed MS-LLLME-FASI-CE-UV method were in the range of 0.02-0.82 μg/L (based on S/N = 3) with enrichment factors of 546- to 7300-fold for the target analytes. The RSDs of the developed method were in the range of 6.7-12.9% (n = 7). Good linearity (R(2) = 0.9928-0.9997) was obtained in concentration range of 0.1-100 μg/L for mexiletine and propranolol, 0.2-100 μg/L for xylocaine and metoprolol, 0.5-100 μg/L for propafenone and 2.0-100 μg/L for carvedilol, respectively. The developed method was successfully applied for real-time determination of metoprolol in human urine samples within 26 h after uptake.

  10. On-line sequential injection dispersive liquid-liquid microextraction system for flame atomic absorption spectrometric determination of copper and lead in water samples.

    PubMed

    Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

    2009-06-30

    A simple, sensitive and powerful on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system was developed as an alternative approach for on-line metal preconcentration and separation, using extraction solvent at microlitre volume. The potentials of this novel schema, coupled to flame atomic absorption spectrometry (FAAS), were demonstrated for trace copper and lead determination in water samples. The stream of methanol (disperser solvent) containing 2.0% (v/v) xylene (extraction solvent) and 0.3% (m/v) ammonium diethyldithiophosphate (chelating agent) was merged on-line with the stream of sample (aqueous phase), resulting a cloudy mixture, which was consisted of fine droplets of the extraction solvent dispersed entirely into the aqueous phase. By this continuous process, metal chelating complexes were formed and extracted into the fine droplets of the extraction solvent. The hydrophobic droplets of organic phase were retained into a microcolumn packed with PTFE-turnings. A portion of 300 microL isobutylmethylketone was used for quantitative elution of the analytes, which transported directly to the nebulizer of FAAS. All the critical parameters of the system such as type of extraction solvent, flow-rate of disperser and sample, extraction time as well as the chemical parameters were studied. Under the optimum conditions the enhancement factor for copper and lead was 560 and 265, respectively. For copper, the detection limit and the precision (R.S.D.) were 0.04 microg L(-1) and 2.1% at 2.0 microg L(-1) Cu(II), respectively, while for lead were 0.54 microg L(-1) and 1.9% at 30.0 microg L(-1) Pb(II), respectively. The developed method was evaluated by analyzing certified reference material and applied successfully to the analysis of environmental water samples.

  11. A novel dual-valve sequential injection manifold (DV-SIA) for automated liquid-liquid extraction. Application for the determination of picric acid.

    PubMed

    Skrlíková, Jana; Andruch, Vasil; Sklenárová, Hana; Chocholous, Petr; Solich, Petr; Balogh, Ioseph S

    2010-05-07

    A novel dual-valve sequential injection system (DV-SIA) for online liquid-liquid extraction which resolves the main problems of LLE utilization in SIA has been designed. The main idea behind this new design was to construct an SIA system by connecting two independent units, one for aqueous-organic mixture flow and the second specifically for organic phase flow. As a result, the DV-SIA manifold consists of an Extraction unit and a Detection unit. Processing a mixture of aqueous-organic phase in the Extraction unit and a separated organic phase in the Detection unit solves the problems associated with the change of phases having different affinities to the walls of the Teflon tubing used in the SI-system. The developed manifold is a simple, user-friendly and universal system built entirely from commercially available components. The system can be used for a variety of samples and organic solvents and is simple enough to be easily handled by operators less familiar with flow systems. The efficiency of the DV-SIA system is demonstrated by the extraction of picric acid in the form of an ion associate with 2-[2-(4-methoxy-phenylamino)-vinyl]-1,3,3-trimethyl-3H-indolium reagent, with subsequent spectrophotometric detection. The suggested DV-SIA concept can be expected to stimulate new experiments in analytical laboratories and can be applied to the elaboration of procedures for the determination of other compounds extractable by organic solvents. It could thus form a basis for the design of simple, single-purpose commercial instruments used in LLE procedures.

  12. Film effectiveness over a flat surface with air and CO{sub 2} injection through compound angle holes using a transient liquid crystal image method

    SciTech Connect

    Ekkad, S.V.; Zapata, D.; Han, J.C.

    1997-07-01

    This paper presents detailed film effectiveness distributions over a flat surface with one row of injection holes inclined streamwise at 35 deg for three blowing ratios (M = 0.5, 1.0, 2.0). Three compound angles of 0, 45, and 90 deg with air (D.R. = 0.98) and CO{sub 2} (D.R. = 1.46) as coolants are tested at an elevated free-stream turbulence condition (Tu {approx} 8.5%). A transient liquid crystal technique is used to measure local heat transfer coefficients and film effectiveness. Detailed film effectiveness results are presented near and around film injection holes. Compound angle injection provides higher film effectiveness than simple angle injection for both coolants. Higher density injectant produces higher effectiveness for simple injection. However, lower density coolant produces higher effectiveness obtained using the transient liquid crystal technique, particularly in the near-hole region, provided a better understanding of the film cooling process in gas turbine components.

  13. Fast determination of 40 drugs in water using large volume direct injection liquid chromatography-tandem mass spectrometry.

    PubMed

    Boix, Clara; Ibáñez, María; Sancho, Juan V; Rambla, Javier; Aranda, José L; Ballester, Salomé; Hernández, Félix

    2015-01-01

    This work describes a rapid analytical method based on direct sample injection of water samples for the simultaneous identification/quantification of 40 emerging compounds, including pharmaceuticals and drugs of abuse. The water samples were analyzed by ultra-high-performance liquid chromatography coupled to hybrid triple quadrupole mass spectrometer (UHPLC-MS/MS QqQ). Taking profit of the increasing sensitivity of nowadays tandem mass spectrometers, direct sample injection of large volumes has been an attractive alternative to pre-concentration steps. In this work, the developed methodology has been validated at three concentration levels (10, 100 and 1000 ng/L) in 10 different water samples of different types (5 effluent wastewater and 5 surface water samples). The majority of compounds could be satisfactory validated at these concentrations, showing good recoveries and precision. With only few exceptions, the limits of quantification (LOQs), estimated from the sample chromatogram at lowest spiked level tested, were below 3 ng/L. The method was applied to the analysis of 10 effluent wastewater and 10 surface water samples. Venlafaxine was the compound most frequently detected (80%) in surface water, followed by acetaminophen (70%). Regarding effluent wastewater, valsartan and 4-acetyl aminoantipyrine were detected in 9 out of 10 samples analyzed. These two compounds together with 4-formyl aminoantipyrine and naproxen showed the highest concentrations (>2000 ng/L). In these cases, a dilution step was required for a correct quantification. As an additional evaluation of the method performance, the same water samples were analyzed in another laboratory by a second analytical methodology, based on on-line solid-phase-extraction coupled to LC-MS/MS (QqQ).

  14. Flow injection analysis of trace chromium (VI) in drinking water with a liquid waveguide capillary cell and spectrophotometric detection.

    PubMed

    Ma, Jian; Yuan, Dongxing; Byrne, Robert H

    2014-01-01

    Hexavalent chromium (Cr(VI)) is an acknowledged hazardous material in drinking waters. As such, effective monitoring and assessment of the risks posed by Cr(VI) are important analytical objectives for both human health and environmental science. However, because of the lack of highly sensitive, rapid, and simple procedures, a relatively limited number of studies have been carried out in this field. Here we report a simple and sensitive analytical procedure of flow injection analysis (FIA) for sub-nanomolar Cr(VI) in drinking water samples with a liquid core waveguide capillary cell (LWCC). The procedure is based on a highly selective reaction between 1, 5-diphenylcarbazide and Cr(VI) under acidic conditions. The optimized experimental parameters included reagent concentrations, injection volume, length of mixing coil, and flow rate. Measurements at 540 nm, and a 650-nm reference wavelength, produced a 0.12-nM detection limit. Relative standard deviations for 1, 2, and 10 nM samples were 5.6, 3.6, and 0.72 % (n = 9), and the analysis time was <2 min sample(-1). The effects of salinity and interfering ions, especially Fe(III), were evaluated. Using the FIA-LWCC method, different sources of bottled waters and tap waters were examined. The Cr(VI) concentrations of the bottled waters ranged from the detection limit to ∼20 nM, and tap waters collected from the same community supply had Cr(VI) concentration around 14 nM.

  15. Ionic liquid and aqueous two-phase extraction based on salting-out coupled with high-performance liquid chromatography for the determination of seven rare ginsenosides in Xue-Sai-Tong injection.

    PubMed

    Li, Lan-Jie; Jin, Yong-Ri; Wang, Xiao-Zhong; Liu, Ying; Wu, Qian; Shi, Xiao-Lei; Li, Xu-Wen

    2015-09-01

    A method of ionic liquid salt aqueous two-phase extraction coupled with high-performance liquid chromatography has been developed for the analysis of seven rare ginsenosides including Rg6 , F4 , 20(S)-Rg3 , 20(R)-Rg3 , Rk3 , Rk1 , and Rg5 in Xue-Sai-Tong injection. The injection was mixed with ionic liquid 1-butyl-3-methylimidazolium bromide aqueous solution, and a mixture was obtained. With the addition of sodium dodecyl sulfate and dipotassium phosphate into the mixture, the aqueous two-phase mixture was formed after ultrasonic treatment and centrifuged. Rare ginsenosides were extracted into the upper phase. To obtain a high extraction factors, various influences were considered systematically, such as the volume of ionic liquid, the category and amount of salts, the amount of sodium dodecyl sulfate, the pH value of system, and the time of ultrasonic treatment. Under the optimal condition, rare ginsenosides in Xue-Sai-Tong injection were enriched and detected, the recoveries of seven rare ginsenosides ranged from 90.05 to 112.55%, while relative standard deviations were lower than 2.50%. The developed method was reliable, rapid and sensitive for the determination of seven rare ginsenosides in the injections.

  16. Molecular orientation distributions during injection molding of liquid crystalline polymers: Ex situ investigation of partially filled moldings

    SciTech Connect

    Fang, Jun; Burghardt, Wesley R.; Bubeck, Robert A.

    2013-01-10

    The development of molecular orientation in thermotropic liquid crystalline polymers (TLCPs) during injection molding has been investigated using two-dimensional wide-angle X-ray scattering coordinated with numerical computations employing the Larson-Doi polydomain model. Orientation distributions were measured in 'short shot' moldings to characterize structural evolution prior to completion of mold filling, in both thin and thick rectangular plaques. Distinct orientation patterns are observed near the filling front. In particular, strong extension at the melt front results in nearly transverse molecular alignment. Far away from the flow front shear competes with extension to produce complex spatial distributions of orientation. The relative influence of shear is stronger in the thin plaque, producing orientation along the filling direction. Exploiting an analogy between the Larson-Doi model and a fiber orientation model, we test the ability of process simulation tools to predict TLCP orientation distributions during molding. Substantial discrepancies between model predictions and experimental measurements are found near the flow front in partially filled short shots, attributed to the limits of the Hele-Shaw approximation used in the computations. Much of the flow front effect is however 'washed out' by subsequent shear flow as mold filling progresses, leading to improved agreement between experiment and corresponding numerical predictions.

  17. Multidimensional high-performance liquid chromatography on Pinkerton ISRP and RP18 columns: direct serum injection to quantify creatinine.

    PubMed

    Puhlmann, A; Dülffer, T; Kobold, U

    1992-10-02

    A two-dimensional high-performance liquid chromatographic method for the determination of creatinine with direct serum injection without sample pretreatment has been developed. The column-switching technique allowed a switch from columns packed with internal surface reversed-phase (ISRP) material to columns of almost any other material, even if the eluents necessary in a particular case do not appear to be directly compatible. A Pinkerton ISRP column, which stands out because of its very good stability when loaded with undiluted serum samples, was used as precolumn. The creatinine-containing fraction was switched to a reversed-phase Shandon RP18 column and was focused there by alteration of the eluent from pH 6.5 to phosphoric acid-ion-pair reagent. The separation occurs via a pH gradient, with ultraviolet detection at 234 nm. This method stands out particularly for its good long-term stability, simple sample handling without pretreatment, high selectivity, a broad linearity (0.3-30 mg/dl creatinine), good reproducibility (inter-assay coefficient of variation less than 3%) and high recovery (97-100%) relative to values obtained with gas chromatography-mass spectrometry.

  18. A metabolomic strategy to screen the prototype components and metabolites of Qingkailing injection in rat urine by high-performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Guo, Mingxing; Zhang, Li; Liu, Haiyu; Qin, Lingling; Zhang, Zhixin; Bai, Xu; Gao, Xiaoyan

    2014-10-01

    Xenobiotic metabolome identification of Chinese herbal formula in biological systems is a very challenging task. Qingkailing injection is a typical Chinese herbal injection, which is wildly used clinically in China. However, the holistic metabolic fate of the ingredient from Qingkailing injection remains unclear. In this work, a metabolomic strategy for comprehensively elucidating Qingkailing injection derived prototype components and metabolites in rat urine conducted by hybrid linear ion trap high-resolution mass spectrometry was developed. High-performance liquid chromatography coupled with hybrid linear ion trap high-resolution mass spectrometry was developed to obtain the urine profiling between the control group and Qingkailing injection treated group. Orthogonal partial least squares discriminate analysis was applied to distinguish the exogenous and the endogenous. In the S-plot, 37 xenobiotics derived from Qingkailing injection were found in urine, including 18 prototype compounds and 19 metabolites. The characterization of the prototype components and metabolites in rat's urine provided essential data for further pharmacological studies of Qingkailing injection. Our results indicated that the metabolomic approach was an effective tool to discover, screen, and analyze the multiple prototype components and their metabolites from complicated traditional Chinese preparations in vivo.

  19. Silicone Granuloma in the Buttocks Incidentally Detected by 18F-FDG PET/CT 30 Years After Free Liquid Silicone Injections.

    PubMed

    Ohnona, Jessica; Durand, Pauline; Amegnizin, Jean-Louis; Kerrou, Khaldoun

    2016-06-01

    A 59-year-old transexual (male to female) patient presented with a squamous cell carcinoma of the larynx. She underwent an F-FDG PET/CT for initial staging. The examination showed high F-FDG uptake of the primary lesion and a homolateral lymphadenopathy. Incidental heterogeneous uptake of round hyperdense lesions in the gluteal muscles and subcutaneous fat was visualized. The medical history revealed secondly that the patient had had free liquid silicone injections 30 years before the examination. Although the injection of free silicone is not practised since the 1980s, this incidental finding should prompt to check the patient's medical history over several decades.

  20. System innovations for aerosol MOCVD of YBCO superconducting thin films

    NASA Astrophysics Data System (ADS)

    Nelms, David Martin

    System innovations were developed for metallo-organic chemical vapor deposition (MOCVD) in order to achieve two main objectives: to fully characterize a novel feed system while and to demonstrate uniform, superconducting thin films over a 2 inch diameter. The novel aerosol feed system was fully characterized and improved by performing solubility and carbon tests with different metallo-organic solvents and by thermally mapping the heating section. The gas flow profiles in the reactor chamber were modeled with a finite-element software package called Fluent. This enabled us to study different nozzles for improving the uniformity of the velocity near the substrate and the uniformity of the depositions. Depositions were then performed to test the validity of the computer model and to determine correct molar feed ratios. The uniformity was measured with a scanning electron microscope (SEM) while the film compositions were analyzed with a X-Ray photoelectron spectroscopy system (XPS). Once the correct feed compositions were determined, this ratio was used along with the feed nozzle designed to deposit uniform, superconducting thin films.

  1. Thermogravimetric evaluation of the suitability of precursors for MOCVD

    NASA Astrophysics Data System (ADS)

    Kunte, G. V.; Shivashankar, S. A.; Umarji, A. M.

    2008-02-01

    A method based on the Langmuir equation for the estimation of vapour pressure and enthalpy of sublimation of subliming compounds is described. The variable temperature thermogravimetric/differential thermogravimetric (TG/DTG) curve of benzoic acid is used to arrive at the instrument parameters. Employing these parameters, the vapour pressure-temperature curves are derived for salicylic acid and camphor from their TG/DTG curves. The values match well with vapour pressure data in the literature, obtained by effusion methods. By employing the Clausius-Clapeyron equation, the enthalpy of sublimation could be calculated. Extending the method further, two precursors for metal-organic chemical vapour deposition (MOCVD) of titanium oxide bis-isopropyl bis tert-butyl 2-oxobutanoato titanium, Ti(OiPr)2(tbob)2, and bis-oxo-bis-tertbutyl 2-oxobutanoato titanium, [TiO(tbob)2]2, have been evaluated. The complex Ti(OiPr)2(tbob)2 is found to be a more suitable precursor. This approach can be helpful in quickly screening for the suitability of a compound as a CVD precursor.

  2. Thermal annealing study of as-grown n-type MOCVD GaAs

    NASA Astrophysics Data System (ADS)

    Naz, Nazir A.; Qurashi, Umar S.; Zafar Iqbal, M.

    2007-12-01

    Results of isochronal annealing up to a temperature of 660 K of n-type GaAs grown by low-pressure metal organic chemical vapor deposition (LP-MOCVD) are reported. Deep-level transient spectroscopy (DLTS) reveals EL2 as the only electron-emitting deep-level defect in our as-grown material, whereas three hole-emitting levels at Ev+0.09 eV, Ev+0.40 eV and Ev+0.93 eV are observed in the minority-carrier injection spectra. While yielding interesting results on the behavior of these pre-existing deep-level defects, thermal annealing is found to introduce at least four new defects, three in the upper half of the band gap at Ec-0.13 eV, Ec-0.16 eV and Ec-0.36 eV, and one in the lower half at Ev+0.19 eV. Two of these defects, one at Ec-0.16 eV and the other at Ec-0.36 eV, are identified with previously reported annealed-in deep levels in n-GaAs, while the other two defects cannot be identified with any of the deep levels reported in the literature. Data on the annealing behavior and other characteristics of these annealed-in levels are presented. All the pre-existing inadvertent deep-level defects in the as-grown material were found to be stable up to 600 K, beyond which the minority-carrier emitting levels start to anneal out, but EL2 tends to show a slight increase with annealing temperature.

  3. Rapid determination of benzodiazepines, zolpidem and their metabolites in urine using direct injection liquid chromatography-tandem mass spectrometry.

    PubMed

    Jeong, Yu-Dong; Kim, Min Kyung; Suh, Sung Ill; In, Moon Kyo; Kim, Jin Young; Paeng, Ki-Jung

    2015-12-01

    Benzodiazepines and zolpidem are generally prescribed as sedative, hypnotics, anxiolytics or anticonvulsants. These drugs, however, are frequently misused in drug-facilitated crime. Therefore, a rapid and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of benzodiazepines, zolpidem and their metabolites in urine using deuterium labeled internal standards (IS). Urine samples (120 μL) mixed with 80 μL of the IS solution were centrifuged. An aliquot (5 μL) of the sample solution was directly injected into the LC-MS/MS system for analysis. The mobile phases consisted of water and acetonitrile containing 2mM ammonium trifluoroacetate and 0.2% acetic acid. The analytical column was a Zorbax SB-C18 (100 mm × 2.1 mm i.d., 3.5 μm, Agilent). The separation and detection of 18 analytes were achieved within 10 min. Calibration curves were linear over the concentration ranges of 0.5-20 ng/mL (zolpidem), 1.0-40 ng/mL (flurazepam and temazepam), 2.5-100 ng/mL (7-aminoclonazepam, 1-hydroxymidazolam, midazolam, flunitrazepam and alprazolam), 5.0-200 ng/mL (zolpidem phenyl-4-carboxylic acid, α-hydroxyalprazolam, oxazepam, nordiazepam, triazolam, diazepam and α-hydroxytriazolam), 10-400 ng/mL (lorazepam and desalkylflurazepam) and 10-100 ng/mL (N-desmethylflunitrazepam) with the coefficients of determination (r(2)) above 0.9971. The dilution integrity of the analytes was examined for supplementation of short linear range. Dilution precision and accuracy were tested using two, four and ten-folds dilutions and they ranged from 3.7 to 14.4% and -12.8 to 12.5%, respectively. The process efficiency for this method was 63.0-104.6%. Intra- and inter-day precisions were less than 11.8% and 9.1%, while intra- and inter-day accuracies were less than -10.0 to 8.2%, respectively. The lower limits of quantification were lower than 10 ng/mL for each analyte. The applicability of the developed method was successfully

  4. Simultaneous Determination of 13 Priority Polycyclic Aromatic Hydrocarbons in Tehran’s Tap Water and Water for Injection Samples Using Dispersive Liquid-Liquid Micro Extraction Method and Gas Chromatography-Mass Spectrometry

    PubMed Central

    Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayate, Mitra

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for injection. Dispersive liquid-liquid microextraction procedure combined with gas chromatography-mass spectrometry was used for the extraction and determination of PAHs in the samples. Under the optimized conditions, the range of extraction recoveries and relative standard deviations (RSDs) of PAHs in water using internal standard (anthracene-d10) were in the range of 71-90% and 4-16%, respectively. Limit of detection for different PAHs were between 0.03 and 0.1 ngmL-1. The concentration of PAHs in all tap water as well as water for injection samples were lower than the limit of quantification of PAHs. This is the first study addressing the occurrence of PAHs in water for injection samples in Iran using dispersive liquid-liquid micro extraction procedure combined with gas chromatography-mass spectrometry. PMID:27642318

  5. Simultaneous Determination of 13 Priority Polycyclic Aromatic Hydrocarbons in Tehran's Tap Water and Water for Injection Samples Using Dispersive Liquid-Liquid Micro Extraction Method and Gas Chromatography-Mass Spectrometry.

    PubMed

    Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayate, Mitra

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for injection. Dispersive liquid-liquid microextraction procedure combined with gas chromatography-mass spectrometry was used for the extraction and determination of PAHs in the samples. Under the optimized conditions, the range of extraction recoveries and relative standard deviations (RSDs) of PAHs in water using internal standard (anthracene-d10) were in the range of 71-90% and 4-16%, respectively. Limit of detection for different PAHs were between 0.03 and 0.1 ngmL(-1). The concentration of PAHs in all tap water as well as water for injection samples were lower than the limit of quantification of PAHs. This is the first study addressing the occurrence of PAHs in water for injection samples in Iran using dispersive liquid-liquid micro extraction procedure combined with gas chromatography-mass spectrometry.

  6. Determination of phosphodiesterase type V inhibitors in wastewater by direct injection followed by liquid chromatography coupled to tandem mass spectrometry.

    PubMed

    Causanilles, Ana; Emke, Erik; de Voogt, Pim

    2016-09-15

    A simple, fast and reliable analytical method for the determination of phosphodiesterase type V inhibitors in wastewater was developed and validated. The method was based on direct injection followed by liquid chromatography coupled to tandem mass spectrometry with triple quadrupole as mass analyzer. Transformation products and analogues were included in the target list besides the three active pharmaceutical ingredients (sildenafil, vardenafil and tadalafil). The method performance was thoroughly investigated, including the analyte stability in wastewater and matrix effect. All target compounds presented linear fits between their LOD and 500ng/L. The quantification limits ranged from 1.6 to 30ng/L for all compounds except for n-octylnortadalafil (LOQ: 100ng/L); precision calculated as intraday repeatability was lower than 30%; accuracy calculated as procedural recovery ranged successfully between 85 and 105% in all cases. The method was applied to samples collected during three week-long monitoring campaigns performed in 2013, 2014 and 2015 in three Dutch cities. Only sildenafil and its two metabolites, desmethyl- and desethylsildenafil, were present with normalized loads ranging from LOQ to 8.3, 11.8 and 21.6mg/day/1000 inh, respectively. Two additional week-long sets of samples were collected in Amsterdam at the time that a festival event took place, bringing around 350,000 visitors to the city. The difference in drug usage patterns was statistically studied: "weekday" versus "weekend", "normal" versus "atypical" week; and results discussed. The metabolite to parent drug concentration ratio evolution during consecutive years was discussed, leading to several possible explanations that should be further investigated. Finally, wastewater-based epidemiology approach was applied to back-calculate sildenafil consumption.

  7. Influence of Natural Convection and Thermal Radiation Multi-Component Transport in MOCVD Reactors

    NASA Technical Reports Server (NTRS)

    Lowry, S.; Krishnan, A.; Clark, I.

    1999-01-01

    The influence of Grashof and Reynolds number in Metal Organic Chemical Vapor (MOCVD) reactors is being investigated under a combined empirical/numerical study. As part of that research, the deposition of Indium Phosphide in an MOCVD reactor is modeled using the computational code CFD-ACE. The model includes the effects of convection, conduction, and radiation as well as multi-component diffusion and multi-step surface/gas phase chemistry. The results of the prediction are compared with experimental data for a commercial reactor and analyzed with respect to the model accuracy.

  8. High-performance InGaN/GaN MQW LEDs with Al-doped ZnO transparent conductive layers grown by MOCVD using H2O as an oxidizer

    NASA Astrophysics Data System (ADS)

    Lin, Jia-Yong; Pei, Yan-Li; Zhuo, Yi; Chen, Zi-Min; Hu, Rui-Qin; Cai, Guang-Shuo; Wang, Gang

    2016-11-01

    In this study, the high performance of InGaN/GaN multiple quantum well light-emitting diodes (LEDs) with Al-doped ZnO (AZO) transparent conductive layers (TCLs) has been demonstrated. The AZO-TCLs were fabricated on the n+-InGaN contact layer by metal organic chemical vapor deposition (MOCVD) using H2O as an oxidizer at temperatures as low as 400 °C without any post-deposition annealing. It shows a high transparency (98%), low resistivity (510-4 Ω·cm), and an epitaxial-like excellent interface on p-GaN with an n+-InGaN contact layer. A forward voltage of 2.82 V @ 20 mA was obtained. Most importantly, the power efficiencies can be markedly improved by 53.8%@20 mA current injection and 39.6%@350 mA current injection compared with conventional LEDs with indium tin oxide TCL (LED-III), and by 28.8%@20 mA current injection and 4.92%@350 mA current injection compared with LEDs with AZO-TCL prepared by MOCVD using O2 as an oxidizer (LED-II), respectively. The results indicate that the AZO-TCL grown by MOCVD using H2O as an oxidizer is a promising TCL for a low-cost and high-efficiency GaN-based LED application. Project supported by the National Natural Science Foundation of China (Grant Nos. 61204091, 61404177, 51402366, and U1201254) and the Science and Technology Planning Project of Guangdong Province, China (Grant No. 2015B010132006).

  9. Integrating qualitative and quantitative characterization of traditional Chinese medicine injection by high-performance liquid chromatography with diode array detection and tandem mass spectrometry.

    PubMed

    Xie, Yuan-yuan; Xiao, Xue; Luo, Juan-min; Fu, Chan; Wang, Qiao-wei; Wang, Yi-ming; Liang, Qiong-lin; Luo, Guo-an

    2014-06-01

    The present study aims to describe and exemplify an integrated strategy of the combination of qualitative and quantitative characterization of a multicomponent mixture for the quality control of traditional Chinese medicine injections with the example of Danhong injection (DHI). The standardized chemical profile of DHI has been established based on liquid chromatography with diode array detection. High-performance liquid chromatography coupled with time-of-flight mass spectrometry and high-performance liquid chromatography with electrospray multistage tandem ion-trap mass spectrometry have been developed to identify the major constituents in DHI. The structures of 26 compounds including nucleotides, phenolic acids, and flavonoid glycosides were identified or tentatively characterized. Meanwhile, the simultaneous determination of seven marker constituents, including uridine, adenosine, danshensu, protocatechuic aldehyde, p-coumaric acid, rosmarinic acid, and salvianolic acid B, in DHI was performed by multiwavelength detection based on high-performance liquid chromatography with diode array detection. The integrated qualitative and quantitative characterization strategy provided an effective and reliable pattern for the comprehensive and systematic characterization of the complex traditional Chinese medicine system.

  10. Studies on the mixing of liquid jets and pre-atomized sprays in confined swirling air flows for lean direct injection combustion

    NASA Astrophysics Data System (ADS)

    Huh, Jun-Young

    A lean direct injection (LDI) combustion concept was introduced recently to obtain both low NOsbx emissions and high performance for advanced aircraft gas turbine engines. It was reported that pollutant emissions, especially NOsbx, in a lean combustion mode depend significantly on the degree of mixing (mixedness) of supplied air and liquid fuel droplets. From a viewpoint of environmental protection, therefore, uniform mixing of fuel and air in a very short period of time, i.e., well-stirred mixing, is crucially important in the LDI combustion mode. In the present study, as the first stage toward understanding the combustion phenomena in a lean direct injection (LDI) mode, the hydrodynamic behavior of liquid jets and pre-atomized sprays in confined swirling air flows is investigated. Laser-based flow visualization and image analysis techniques are applied to analyze the instantaneous motion of the mixing process of the jets and pre-atomized sprays. Statistical analysis system (SAS) software is utilized to analyze the experimental data, and correlate experimental parameters. Statistical parameters, such as centrality, degree of spread, and total area ratio of particles, are defined in this study, and used to quantify the mixedness (degree of mixing) of liquid particles in confined geometry. Two empirical equations are obtained to predict jet intact lengths and spray angles, respectively, in confined swirling air flows. It is found that initial jet characteristics, such as intact length and spray angle, determine the mixing of the liquid particles resulting from the jet. It is verified that image analysis is feasible in quantitative determination of the mixedness of liquid particles. Even though substantial improvements in liquid fuel injector systems are required before they can be considered adequate for LDI combustion at high pressure and high temperature, the results and ideas obtained from the present study will help engineers find better mixing methods for LDI

  11. High Throughput of Reel-to-reel MOCVD-YBCO on Different CSD-and MOCVD-buffered Cube Textured Ni-substrates

    NASA Astrophysics Data System (ADS)

    Muydinov, Ruslan; Stadel, Oliver; Falter, Martina; BŠcker, Michael

    Cheap chemical approaches: CSD/MOD and MOCVD were used and demonstrated to be feasible in 2G-wire production. New reel-to-reel MOCVD pilot system with higher throughput was examined, tuned and used in all YBCO depositions as well as for MgO, LMO, YSZ and CeO2 buffer layers fabrication. YBCO deposition process was found to be stable either at 10 m/h on 50 m long tapes or at 20 m/h on 100 m long tapes. All-layers-by-MOCVD approach allowed to get critical current up to Ic max > 90A/cm-width. On a single CSD-LZO (lanthanum zirconate) buffered Ni-alloy tapes 400 nm thick YBCO films with critical current density up to jc max = 1.5 MA/cm2 were obtained. On the basis of single CSD-LZO-buffered tapes, some multiple buffer sandwiches were created and compared in the same YBCO deposition. The best result was reached on CVD-CeO2/1×CSD-LZO/Ni5W buffer oxide system and showed for 650 nm thick YBCO rather stable over 2.5 m length Ic = 80-90 A.

  12. Growth and characterization of CdS buffer layers by CBD and MOCVD

    SciTech Connect

    Morrone, A.A.; Huang, C.; Li, S.S.

    1999-03-01

    Thin film CdS has been widely used in thin-film photovoltaic devices. The most efficient Cu(In,&hthinsp;Ga)Se{sub 2} (CIGS) solar cells reported to date utilized a thin CdS buffer layer prepared by a reactive solution growth technique known as chemical bath deposition (CBD). Considerable effort has been directed to better understand the role and find a replacement for the CBD CdS process in CIGS-based solar cells. We reported a low temperature ({approximately}150&hthinsp;{degree}C) Metalorganic Chemical Vapor Deposition (MOCVD) CdS thin film buffer layer process for CIGS absorbers. Many prior studies have reported that CBD CdS contains a mixture of crystal structures. Recent investigations of CBD CdS thin films by ellipsometry suggested a multilayer structure. In this study we compare CdS thin films prepared by CBD and MOCVD and the effects of annealing. TED and XRD are used to characterize the crystal structure, the film microstructure is studied by HRTEM, and the optical properties are studied by Raman and spectrophotometry. All of these characterization techniques reveal superior crystalline film quality for CdS films grown by MOCVD compared to those grown by CBD. Dual Beam Optical Modulation (DBOM) studies showed that the MOCVD and CBD CdS buffer layer processes have nearly the same effect on CIGS absorbers when combined with a cadmium partial electrolyte aqueous dip. {copyright} {ital 1999 American Institute of Physics.}

  13. Method for Improving Mg Doping During Group-III Nitride MOCVD

    DOEpatents

    Creighton, J. Randall; Wang, George T.

    2008-11-11

    A method for improving Mg doping of Group III-N materials grown by MOCVD preventing condensation in the gas phase or on reactor surfaces of adducts of magnesocene and ammonia by suitably heating reactor surfaces between the location of mixing of the magnesocene and ammonia reactants and the Group III-nitride surface whereon growth is to occur.

  14. Method for the quantification of vanadyl porphyrins in fractions of crude oils by High Performance Liquid Chromatography-Flow Injection-Inductively Coupled Plasma Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Wandekoken, Flávia G.; Duyck, Christiane B.; Fonseca, Teresa C. O.; Saint'Pierre, Tatiana D.

    2016-05-01

    High performance liquid chromatography hyphenated by flow injection to inductively coupled plasma mass spectrometry (HPLC-FI-ICP-MS) was used to investigate V linked to porphyrins present in fractions of crude oil. First, the crude oil sample was submitted to fractionation by preparative liquid chromatography with UV detection, at the porphyrin Soret band wavelength (400 nm). The obtained porphyrin fractions were then separated in a 250 mm single column, in the HPLC, and eluted with different mobile phases (methanol or methanol:toluene (80:20; v:v)). The quantification of V-porphyrins in the fractions eluted from HPLC was carried out by online measuring the 51V isotope in the ICP-MS, against vanadyl octaethylporphine standard solutions (VO-OEP), prepared in the same solvent as the mobile phase, and injected post-column directly into the plasma. A 20 μg L- 1 Ge in methanol was used as internal standard for minimizing non-spectral interference, such as short-term variations due to injection. The mathematical treatment of the signal based on Fast Fourier Transform smoothing algorithm was employed to improve the precision. The concentrations of V as V-porphyrins were between 2.7 and 11 mg kg- 1 in the fractions, which were close to the total concentration of V in the porphyrin fractions of the studied crude oil.

  15. Hollow-fiber liquid-phase microextraction for the direct determination of flumequine in urban wastewaters by flow-injection analysis with terbium-sensitized chemiluminescence.

    PubMed

    Ocaña-González, Juan Antonio; Ramos-Payán, María; Fernández-Torres, Rut; Callejón-Mochón, Manuel; Bello-López, Miguel Ángel

    2014-10-01

    A flow-injection analysis chemiluminescence method based on the enhancement effect of the flumequine-Tb(III) complex on the weak native emission of the Ce(IV)-Na2SO3 system has been developed for the determination of flumequine. The method includes a cleanup and preconcentration stage (750-fold) of the sample by hollow-fiber liquid-phase microextraction using an Accurel(®) Q 3/2 polypropylene hollow fiber impregnated with 1-octanol as the supported liquid membrane. The obtained 50 μL acceptor phase was injected in a 1 mM Tb(III) + 4 mM Ce(IV) in 5% v/v H2 SO4 stream and mixed with a 2 mM Na2 SO3 stream before its introduction into the flow cell. The chemiluminescence signal was linear in the 0.3-15 ng/mL range, with detection and quantitation limits of 0.1 and 0.3 ng/mL, respectively. The method allows the selective extraction and determination of flumequine in wastewater samples, using simpler and lower-cost instrumentation and with shorter extraction and analysis times than traditional high-performance liquid chromatography analysis.

  16. Photographic Study of Combustion in a Rocket Engine I : Variation in Combustion of Liquid Oxygen and Gasoline with Seven Methods of Propellant Injection

    NASA Technical Reports Server (NTRS)

    Bellman, Donald R; Humphrey, Jack C

    1948-01-01

    Motion pictures at camera speeds up to 3000 frames per second were taken of the combustion of liquid oxygen and gasoline in a 100-pound-thrust rocket engine. The engine consisted of thin contour and injection plates clamped between two clear plastic sheets forming a two-dimensional engine with a view of the entire combustion chamber and nozzle. A photographic investigation was made of the effect of seven methods of propellant injection on the uniformity of combustion. From the photographs, it was found that the flame front extended almost to the faces of the injectors with most of the injection methods, all the injection systems resulted in a considerable nonuniformity of combustion, and luminosity rapidly decreased in the divergent part of the nozzle. Pressure vibration records indicated combustion vibrations that approximately corresponded to the resonant frequencies of the length and the thickness of the chamber. The combustion temperature divided by the molecular weight of the combustion gases as determined from the combustion photographs was about 50 to 70 percent of the theoretical value.

  17. Simultaneous determination of nanomolar nitrite and nitrate in seawater using reverse flow injection analysis coupled with a long path length liquid waveguide capillary cell.

    PubMed

    Feng, Sichao; Zhang, Min; Huang, Yongming; Yuan, Dongxing; Zhu, Yong

    2013-12-15

    A reverse flow injection analysis (rFIA) method coupled with 1m liquid waveguide capillary cell and spectrophotometric detection for simultaneous determination of nanomolar nitrite and nitrate in seawater was developed. The design of two analytical channels sharing the same detection system in the proposed method allowed the analysis of both nitrite and nitrate with single sample injection. Different strategies of reagent injection were investigated to obtain a higher sensitivity and a better peak shape. A dual-wavelength detection mode was chosen to eliminate the light source shifting and sample matrix interference. Experimental parameters were optimized based on a univariate experimental design and the matrix effect from seawater was preliminarily investigated. The proposed method had high sensitivity with detection limit of 0.6 nmol L(-1) for both nitrite and nitrate. The linearity was 2-500 nmol L(-1) for both analytes, and the upper limit could be extended by choosing a lower sensitivity detection wavelength. The analytical results of 26 surface seawater samples obtained with the proposed method showed good agreement with those using a reference method operated using an automated segmented flow analyzer. The proposed method could greatly minimize the trouble introduced by bubbles in the segmented flow analyzer. It also had the advantages of high precision and high sample throughput (nitrite and nitrate detected in triplicate; 5 h(-1)). Compared to normal flow injection analysis, the rFIA method is superior due to its lower reagent consumption, less dispersion of sample, as well as higher sensitivity.

  18. Single column comprehensive analysis of pharmaceutical preparations using dual-injection mixed-mode (ion-exchange and reversed-phase) and hydrophilic interaction liquid chromatography.

    PubMed

    Kazarian, Artaches A; Taylor, Mark R; Haddad, Paul R; Nesterenko, Pavel N; Paull, Brett

    2013-12-01

    The comprehensive separation and detection of hydrophobic and hydrophilic active pharmaceutical ingredients (APIs), their counter-ions (organic, inorganic) and excipients, using a single mixed-mode chromatographic column, and a dual injection approach is presented. Using a mixed-mode Thermo Fisher Acclaim Trinity P1 column, APIs, their counter-ions and possible degradants were first separated using a combination of anion-exchange, cation-exchange and hydrophobic interactions, using a mobile phase consisting of a dual organic modifier/salt concentration gradient. A complementary method was also developed using the same column for the separation of hydrophilic bulk excipients, using hydrophilic interaction liquid chromatography (HILIC) under high organic solvent mobile phase conditions. These two methods were then combined within a single gradient run using dual sample injection, with the first injection at the start of the applied gradient (mixed-mode retention of solutes), followed by a second sample injection at the end of the gradient (HILIC retention of solutes). Detection using both ultraviolet absorbance and refractive index enabled the sensitive detection of APIs and UV-absorbing counter-ions, together with quantitative determination of bulk excipients. The developed approach was applied successfully to the analysis of a dry powder inhalers (Flixotide(®), Spiriva(®)), enabling comprehensive quantification of all APIs and excipients in the sample.

  19. Online solid-phase extraction with high-performance liquid chromatography and mass spectrometry for the determination of five tannins in traditional Chinese medicine injections.

    PubMed

    Sun, Meng; Lin, Yuanyuan; Zhang, Jie; Zheng, Shaohua; Wang, Sicen

    2016-03-01

    A rapid analytical method based on online solid-phase extraction with high-performance liquid chromatography and mass spectrometry has been established and applied to the determination of tannin compounds that may cause adverse effects in traditional Chinese medicine injections. Different solid-phase extraction sorbents have been compared and the elution buffer was optimized. The performance of the method was verified by evaluation of recovery (≥40%), repeatability (RSD ≤ 6%), linearity (r(2) ≥ 0.993), and limit of quantification (≤0.35 μg/mL). Five tannin compounds, gallic acid, cianidanol, gallocatechin gallate, ellagic acid, and penta-O-galloylglucose, were identified with concentrations ranging from 3.1-37.4 μg/mL in the analyzed traditional Chinese medicine injections.

  20. Decompaction and fluidization of a saturated and confined granular medium by injection of a viscous liquid or gas.

    PubMed

    Johnsen, Ø; Chevalier, C; Lindner, A; Toussaint, R; Clément, E; Måløy, K J; Flekkøy, E G; Schmittbuhl, J

    2008-11-01

    We compare quantitatively two experimental situations concerning injection of a miscible fluid into an initially jammed granular medium saturated with the same fluid, confined in a Hele-Shaw cell. The two experiments are identical, apart from the interstitial and injected fluid, which is in one case air injected into a dry granular packing, and in the other case silicone oil injected into a dense suspension. In spite of the strong differences regarding the nature of the two fluids, strikingly similar dynamical and geometrical features are identified as functions of the control parameters: cell thickness and applied fluid injection pressure. In both cases an initial hydrodynamically driven decompaction process controls the unjamming and prepares the final displacement process characterized by fingerlike patterns empty of grains. The pattern shapes are comparable. In addition, the mobilities of the coupled fluid-grain flow, rescaled by the interstitial fluid viscosity and grain diameter squared, are of the same range and behave comparably. The mobility proves to depend on the initial solid fraction of the medium. Subtle differences are observed in geometrical aspects like the finger width with respect to the control parameters.

  1. Pre-column dilution large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of multi-class pesticides in cabbages.

    PubMed

    Zhong, Qisheng; Shen, Lingling; Liu, Jiaqi; Yu, Dianbao; Li, Siming; Yao, Jinting; Zhan, Song; Huang, Taohong; Hashi, Yuki; Kawano, Shin-ichi; Liu, Zhaofeng; Zhou, Ting

    2016-04-15

    Pre-column dilution large volume injection (PD-LVI), a novel sample injection technique for reverse phase ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), was developed in this study. The PD-LVI UHPLC-MS/MS system was designed by slightly modifying the commercial UHPLC-MS/MS equipment with a mixer chamber. During the procedure of PD-LVI, sample solution of 200μL was directly carried by the organic mobile phase to the mixer and diluted with the aqueous mobile phase. After the mixture was introduced to the UHPLC column in a mobile phase of acetonitrile-water (15/85, v/v), the target analytes were stacked on the head of the column until following separation. Using QuEChERS extraction, no additional steps such as solvent evaporation or residue redissolution were needed before injection. The features of PD-LVI UHPLC-MS/MS system were systematically investigated, including the injection volume, the mixer volume, the precondition time and the gradient elution. The efficiency of this approach was demonstrated by direct analysis of 24 pesticides in cabbages. Under the optimized conditions, low limits of detection (0.00074-0.8 ng/kg) were obtained. The recoveries were in the range of 63.3-109% with relative standard deviations less than 8.1%. Compared with common UHPLC-MS/MS technique, PD-LVI UHPLC-MS/MS showed significant advantages such as excellent sensitivity and reliability. The mechanism of PD-LVI was demonstrated to be based on the column-head stacking effect with pre-column dilution. Based on the results, PD-LVI as a simple and effective sample injection technique of reverse phase UHPLC-MS/MS for the analysis of trace analytes in complex samples showed a great promising prospect.

  2. Hot air injection for removal of dense, non-aqueous-phase liquid contaminants from low-permeability soils

    SciTech Connect

    Payne, F.C.

    1996-08-01

    The performance of soil vapor extraction systems for the recovery of volatile and semi-volatile organic compounds is potentially enhanced by the injection of heated air to increase soil temperatures. The soil temperature increase is expected to improve soil vapor extraction (SVE) performance by increasing target compound vapor pressures and by increasing soil permeability through drying. The vapor pressure increase due to temperature rise relieves the vapor pressure limit on the feasibility of soil vapor extraction. However, the system still requires an air flow through the soil system to deliver heat and to recover mobilized contaminants. Although the soil permeability can be increased through drying, very low permeability soils and low permeability soils adjacent to high permeability air flow pathways will be treated slowly, if at all. AR thermal enhancement methods face this limitation. Heated air injection offers advantages relative to other thermal techniques, including low capital and operation costs. Heated air injection is at a disadvantage relative to other thermal techniques due to the low heat capacity of air. To be effective, heated air injection requires that higher air flows be established than for steam injection or radio frequency heating. Heated air injection is not economically feasible for the stratified soil system developed as a standard test for this document. This is due to the inability to restrict heated air flow to the clay stratum when a low-resistance air flow pathway is available in the adjoining sand. However, the technology should be especially attractive, both technically and economically, for low-volatile contaminant recovery from relatively homogeneous soil formations. 16 refs., 2 tabs.

  3. A bulk liquid membrane-flow injection (BLM-FI) coupled system for the preconcentration and determination of vanadium in saline waters.

    PubMed

    Pinto, Juan J; García-Vargas, Manuel; Moreno, Carlos

    2013-01-15

    A bulk liquid membrane-flow injection (BLM-FI) system has been developed for the preconcentration and spectrophotometric determination of vanadium in saline waters. The preconcentration step was based on a bulk liquid membrane containing Aliquat 336 (acting as a carrier) dissolved in dodecane/dodecanol. Vanadium species were chemically pumped due to the pH gradient between the sample (pH 3.2) and the receiving solution (pH 9.8). Vanadium transport through the membrane was monitored by a new and sensitive spectrophotometric method based on its reaction with di-2-pyridyl ketone benzoylhydrazone (dPKBH) in an acidic medium. As a consequence of membrane transport, vanadium was recovered in an ammonium solution, where total vanadium concentration was spectrophotometrically determined at 375 nm, as the pentavalent species, by using a flow injection analysis (FIA) system. Under optimal conditions, this FIA system provided a detection limit of 4.7 μg L(-1) (3s(blank)/m) and RSD 2.72%, for vanadium determination in saline samples. Both preconcentration and determination steps were previously optimized by modified simplex methodologies. The proposed coupled method was successfully applied to the determination of vanadium in a certified reference material (TMDA-62) and in two seawater samples.

  4. Ultra trace determination of 31 pesticides in water samples by direct injection-rapid resolution liquid chromatography-electrospray tandem mass spectrometry.

    PubMed

    Díaz, Laura; Llorca-Pórcel, Julio; Valor, Ignacio

    2008-08-22

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for the detection of pesticides in tap and treated wastewater was developed and validated according to the ISO/IEC 17025:1999. Key features of this method include direct injection of 100 microL of sample, an 11 min separation by means of a rapid resolution liquid chromatography system with a 4.6 mm x 50 mm, 1.8 microm particle size reverse phase column and detection by electrospray ionization (ESI) MS-MS. The limits of detection were below 15 ng L(-1) and correlation coefficients for the calibration curves in the range of 30-2000 ng L(-1) were higher than 0.99. Precision was always below 20% and accuracy was confirmed by external evaluation. The main advantages of this method are direct injection of sample without preparative procedures and low limits of detection that fulfill the requirements established by the current European regulations governing pesticide detection.

  5. Hydrogen no-vent fill testing in a 5 cubic foot (142 liter) tank using spray nozzle and spray bar liquid injection

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Nyland, Ted W.

    1992-01-01

    A total of 38 hydrogen no-vent fill tests were performed in this test series using various size spray nozzles and a spray bar with different hole sizes in a 5 cubic foot receiver tank. Fill levels of 90 percent by volume or greater were achieved in 26 of the tests while maintaining a receiver tank pressure below 30 psia. Spray nozzles were mounted at the top of the tank, whereas, the spray bar was centered in the tank axially. The spray nozzle no-vent fills demonstrated tank pressure and temperature responses comparable to previous test series. Receiver tank pressure responses for the spray bar configuration were similar to the spray nozzle tests with the pressure initially rising rapidly, then leveling off as vapor condenses onto the discharging liquid streams, and finally ramping up near the end of the test due to ullage compression. Both liquid injection techniques tested were capable of filling the receiver tank to 90 percent under variable test conditions. Comparisons between the spray nozzle and spray bar configurations for well matched test conditions indicate the spray nozzle injection technique is more effective in minimizing the receiving tank pressure throughout a no-vent fill compared to the spray bar under normal gravity conditions.

  6. Dispersive liquid-liquid microextraction prior to field-amplified sample injection for the sensitive analysis of 3,4-methylenedioxymethamphetamine, phencyclidine and lysergic acid diethylamide by capillary electrophoresis in human urine.

    PubMed

    Airado-Rodríguez, Diego; Cruces-Blanco, Carmen; García-Campaña, Ana M

    2012-12-07

    A novel capillary zone electrophoresis (CZE) with ultraviolet detection method has been developed and validated for the analysis of 3,4-methylenedioxymethamphetamine (MDMA), lysergic acid diethylamide (LSD) and phencyclidine (PCP) in human urine. The separation of these three analytes has been achieved in less than 8 min in a 72-cm effective length capillary with 50-μm internal diameter. 100 mM NaH(2)PO(4)/Na(2)HPO(4), pH 6.0 has been employed as running buffer, and the separation has been carried out at temperature and voltage of 20°C, and 25kV, respectively. The three drugs have been detected at 205 nm. Field amplified sample injection (FASI) has been employed for on-line sample preconcentration. FASI basically consists in a mismatch between the electric conductivity of the sample and that of the running buffer and it is achieved by electrokinetically injecting the sample diluted in a solvent of lower conductivity than that of the carrier electrolyte. Ultrapure water resulted to be the better sample solvent to reach the greatest enhancement factor. Injection voltage and time have been optimized to 5 kV and 20s, respectively. The irreproducibility associated to electrokinetic injection has been correcting by using tetracaine as internal standard. Dispersive liquid-liquid microextraction (DLLME) has been employed as sample treatment using experimental design and response surface methodology for the optimization of critical variables. Linear responses were found for MDMA, PCP and LSD in presence of urine matrix between 10.0 and 100 ng/mL approximately, and LODs of 1.00, 4.50, and 4.40 ng/mL were calculated for MDMA, PCP and LSD, respectively. The method has been successfully applied to the analysis of the three drugs of interest in human urine with satisfactory recovery percentages.

  7. High-performance liquid chromatographic determination of clindamycin in human plasma or serum: application to the bioequivalency study of clindamycin phosphate injections.

    PubMed

    Liu, C M; Chen, Y K; Yang, T H; Hsieh, S Y; Hung, M H; Lin, E T

    1997-08-29

    This paper presents an assay of clindamycin phosphate injection in human plasma or serum. A 0.5-ml volume of plasma was used with the internal standard, propranolol. The sample was loaded onto a silica extraction column. The column was washed with deionized water and then eluted with methanol. The eluates were evaporated under nitrogen gas. The residue was reconstituted with the mobile phase and injected onto the high-performance liquid chromatographic system: a 5-micron, 25 cm X 4.6 mm I.D. ODS2 column was used with acetonitrile, tetrahydrofuran and 0.05 M phosphate buffer as the mobile phase and with ultraviolet detection at 204 nm. A limit of quantitation of 0.05 microgram/ml was found, with a coefficient of variation of 11.6% (n = 6). The linear range is between 0.05 and 20.00 micrograms/ml and gives a coefficient of determination (r2) or 0.9992. The method has been successfully applied to the bioavailability study of two commercial preparations of clindamycin phosphate injection (300 mg each) in twelve healthy adult male volunteers.

  8. Ion-pair dynamic liquid-phase microextraction combined with injection-port derivatization for the determination of long-chain fatty acids in water samples.

    PubMed

    Wu, Jingming; Lee, Hian Kee

    2006-11-10

    Ion-pair dynamic liquid-phase microextraction coupled to injection-port derivatization has been developed for the determination of long-chain fatty acids in water samples by gas chromatography-mass spectrometry (GC-MS). In this procedure, long-chain fatty acids (C(14), C(16) and C(18)) were converted into their ion-pair complexes with tetrabutylammonium hydrogen sulfate and then extracted by organic solvent (1-octanol) impregnated in the hollow fiber. The dynamic nature of the extraction was represented by the repeated movement of the acceptor phase (organic solvent) in the hollow fiber that was controlled by a syringe pump. Ion pairs of fatty acids quantitatively formed butyl esters in the injection-port of the gas chromatography. Several parameters such as injection temperature, purge-off time, organic solvent, ion-pair reagent, pH, agitation speed, extraction time and the syringe pump parameters (plunger speed and dwell time) have been optimized. The limits of detection were in the range 0.0093-0.015 ng mL(-1) (at a signal-to-noise ratio of 3) under GC-MS-selected ion monitoring mode and the relative standard deviations were between 7.7% and 11.5%. The method was successfully applied to measure long-chain fatty acids in real water samples.

  9. A novel MOCVD reactor for growth of high-quality GaN-related LED layers

    NASA Astrophysics Data System (ADS)

    Hu, Shaolin; Liu, Sheng; Zhang, Zhi; Yan, Han; Gan, Zhiyin; Fang, Haisheng

    2015-04-01

    Gallium nitride (GaN), a direct bandgap semiconductor widely used in bright light-emitting diodes (LEDs), is mostly grown by metal-organic chemical vapor deposition (MOCVD) method. A good reactor design is critical for the production of high-quality GaN thin films. In this paper, we presented a novel buffered distributed spray (BDS) MOCVD reactor with vertical gas sprayers and horizontal gas inlets. Experiments based on a 36×2″ BDS reactor were conducted to examine influence of the process parameters, such as the operating pressure and the gas flow rate, on the growth efficiency and on the layer thickness uniformity. Transmission electron microscopy (TEM) and photoluminescence (PL) are further conducted to evaluate quality of the epitaxial layers and to check performance of the reactor. Results show that the proposed novel reactor is of high performance in growing high-quality thin films, including InGaN/GaN multiquantum wells (MQWs) structures.

  10. Photoreflectance for in-situ characterization of MOCVD growth of semiconductors under micro-gravity conditions

    NASA Technical Reports Server (NTRS)

    Pollak, Fred H.

    1990-01-01

    A contactless electromodulation technique of photoreflectance (PR) was developed for in-situ monitoring of metal-organic chemical vapor deposition (MOCVD) semiconductor growth for micro-gravity applications. PR can be employed in a real MOCVD reactor including rotating substrate (approximately 500 rev/min) in flowing gases and through a diffuser plate. Measurements on GaAs and Ga(0.82)Al(0.18)As were made up to 690 C. The direct band gaps of In(x)Ga(1-x)As (x = 0.07 and 0.16) were evaluated up to 600 C. In order to address the question of real time measurement, the spectra of the direct gap of GaAs at 650 C was obtained in 30 seconds and 15 seconds seems feasible.

  11. Properties of boron-doped ZnO thin films grown by using MOCVD

    NASA Astrophysics Data System (ADS)

    Choi, In-Hwan

    2013-11-01

    Boron-doped ZnO thin films were prepared by using metal organic chemical-vapor deposition (MOCVD) with diethyl zinc and water as precursors and B2H6 as the dopant gas. The effects of the flow rates of H2O and B2H6 on the growth and the electrical properties of boron-doped ZnO thin film were investigated. The maximum carrier concentration and mobility and the minimum resistivity obtained under these experimental conditions were 7 × 1020 /cm3, 42 cm2 /V·sec and 4 × 10-4 Ω·cm, respectively, at room temperature. The electrical properties, growth rates, transmittances, and surface morphologies of the ZnO:B films grown using MOCVD are strongly affected by growth conditions such as the relative flow rates of the precursors and dopant gases and the chamber pressure, and these effects are discussed in detail in this article.

  12. In-situ estimation of MOCVD growth rate via a modified Kalman filter

    SciTech Connect

    Woo, W.W.; Svoronos, S.A.; Sankur, H.O.; Bajaj, J.; Irvine, S.J.C.

    1996-05-01

    In-situ laser reflectance monitoring of metal-organic chemical vapor deposition (MOCVD) is an effective way to monitor growth rate and epitaxial layer thickness of a variety of III-V and II-VI semiconductors. Materials with low optical extinction coefficients, such as ZnTe/GaAs and AlAs/GaAs for a 6,328 {angstrom} HeNe laser, are ideal for such an application. An extended Kalman filter modified to include a variable forgetting factor was applied to the MOCVD systems. The filter was able to accurately estimate thickness and growth rate while filtering out process noise and cope with sudden changes in growth rate, reflectance drift, and bias. Due to the forgetting factor, the Kalman filter was successful, even when based on very simple process models.

  13. Multilayer porous structures of HVPE and MOCVD grown GaN for photonic applications

    NASA Astrophysics Data System (ADS)

    Braniste, T.; Ciers, Joachim; Monaico, Ed.; Martin, D.; Carlin, J.-F.; Ursaki, V. V.; Sergentu, V. V.; Tiginyanu, I. M.; Grandjean, N.

    2017-02-01

    In this paper we report on a comparative study of electrochemical processes for the preparation of multilayer porous structures in hydride vapor phase epitaxy (HVPE) and metal organic chemical vapor phase deposition (MOCVD) grown GaN. It was found that in HVPE-grown GaN, multilayer porous structures are obtained due to self-organization processes leading to a fine modulation of doping during the crystal growth. However, these processes are not totally under control. Multilayer porous structures with a controlled design have been produced by optimizing the technological process of electrochemical etching in MOCVD-grown samples, consisting of five pairs of thin layers with alternating-doping profiles. The samples have been characterized by SEM imaging, photoluminescence spectroscopy, and micro-reflectivity measurements, accompanied by transfer matrix analysis and simulations by a method developed for the calculation of optical reflection spectra. We demonstrate the applicability of the produced structures for the design of Bragg reflectors.

  14. Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

    NASA Astrophysics Data System (ADS)

    Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

    2015-04-01

    We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/μg and 1.72(14) nL/μg were found for Milli-Q water and lysis-binding buffer, respectively.

  15. A review on development of analytical methods to determine monitorable drugs in serum and urine by micellar liquid chromatography using direct injection.

    PubMed

    Esteve-Romero, Josep; Albiol-Chiva, Jaume; Peris-Vicente, Juan

    2016-07-05

    Therapeutic drug monitoring is a common practice in clinical studies. It requires the quantification of drugs in biological fluids. Micellar liquid chromatography (MLC), a well-established branch of Reverse Phase-High Performance Liquid Chromatography (RP-HPLC), has been proven by many researchers as a useful tool for the analysis of these matrices. This review presents several analytical methods, taken from the literature, devoted to the determination of several monitorable drugs in serum and urine by micellar liquid chromatography. The studied groups are: anticonvulsants, antiarrhythmics, tricyclic antidepressants, selective serotonin reuptake inhibitors, analgesics and bronchodilators. We detail the optimization strategy of the sample preparation and the main chromatographic conditions, such as the type of column, mobile phase composition (surfactant, organic solvent and pH), and detection. The finally selected experimental parameters, the validation, and some applications have also been described. In addition, their performances and advantages have been discussed. The main ones were the possibility of direct injection, and the efficient chromatographic elution, in spite of the complexity of the biological fluids. For each substance, the measured concentrations were accurate and precise at their respective therapeutic range. It was found that the MLC-procedures are fast, simple, inexpensive, ecofriendly, safe, selective, enough sensitive and reliable. Therefore, they represent an excellent alternative for the determination of drugs in serum and urine for monitoring purposes.

  16. Final report on LDRD project : outstanding challenges for AlGaInN MOCVD.

    SciTech Connect

    Mitchell, Christine Charlotte; Follstaedt, David Martin; Russell, Michael J.; Cross, Karen Charlene; Wang, George T.; Creighton, James Randall; Allerman, Andrew Alan; Koleske, Daniel David; Lee, Stephen Roger; Coltrin, Michael Elliott

    2005-03-01

    The AlGaInN material system is used for virtually all advanced solid state lighting and short wavelength optoelectronic devices. Although metal-organic chemical vapor deposition (MOCVD) has proven to be the workhorse deposition technique, several outstanding scientific and technical challenges remain, which hinder progress and keep RD&A costs high. The three most significant MOCVD challenges are: (1) Accurate temperature measurement; (2) Reliable and reproducible p-doping (Mg); and (3) Low dislocation density GaN material. To address challenge (1) we designed and tested (on reactor mockup) a multiwafer, dual wavelength, emissivity-correcting pyrometer (ECP) for AlGaInN MOCVD. This system simultaneously measures the reflectance (at 405 and 550 nm) and emissivity-corrected temperature for each individual wafer, with the platen signal entirely rejected. To address challenge (2) we measured the MgCp{sub 2} + NH{sub 3} adduct condensation phase diagram from 65-115 C, at typical MOCVD concentrations. Results indicate that it requires temperatures of 80-100 C in order to prevent MgCp{sub 2} + NH{sub 3} adduct condensation. Modification and testing of our research reactor will not be complete until FY2005. A new commercial Veeco reactor was installed in early FY2004, and after qualification growth experiments were conducted to improve the GaN quality using a delayed recovery technique, which addresses challenge (3). Using a delayed recovery technique, the dislocation densities determined from x-ray diffraction were reduced from 2 x 10{sup 9} cm{sup -2} to 4 x 10{sup 8} cm{sup -2}. We have also developed a model to simulate reflectance waveforms for GaN growth on sapphire.

  17. WETTABILITY ALTERATION OF POROUS MEDIA TO GAS-WETTING FOR IMPROVING PRODUCTIVITY AND INJECTIVITY IN GAS-LIQUID FLOWS

    SciTech Connect

    Abbas Firoozabadi

    2002-10-21

    The authors have performed a number of imbibition tests with the treated and untreated cores in nC{sub 10}, nC{sub 14}, and nC{sub 16} and a natural gas condensate liquid. Imbibition tests for nC{sub 14} and nC{sub 16} were also carried out at elevated temperatures of 100 C and 140 C. An experimental polymer synthesized for the purpose of this project was used in core treatment. Imbibition results are very promising and imply liquid condensate mobility enhancement in the treated core. They also performed flow tests to quantify the increase in well deliverability and to simulate flow under realistic field conditions. In the past we have performed extensive testing of wettability alteration in intermediate gas wetting for polymer FC759 at temperatures of 24 C and 90 C. The results were promising for the purpose of gas well deliverability improvement in gas condensate wells. We used FC759 to lower the surface energy of various rocks. The model fluids nC{sub 10}, and nC{sub 14} were used to represent condensate liquid, and air was used as the gas phase. A new (L-16349) polymer, which has been recently synthesized for the purpose of the project, was used in the work to be presented here. L-16349 is a water-soluble fluorochemical polymer, with low order, neutral PH and very low volatile organic compound (VOC < 9.1 g/l). It is light yellow in appearance and density in 25% solution is 1.1 g/cc. Polymer L-16349 is very safe from environmental considerations and it is economical for our purpose. In this work, in addition to nC{sub 10}, and nC{sub 14}, we used two other liquids nC{sub 16}, and a liquid condensate in order to study the effect of wettability alteration with a broader range of fluids.

  18. MOCVD for solar cells, a transition towards a chamberless inline process

    NASA Astrophysics Data System (ADS)

    Barrioz, V.; Monir, S.; Kartopu, G.; Lamb, D. A.; Brooks, W.; Siderfin, P.; Jones, S.; Clayton, A. J.; Irvine, S. J. C.

    2015-03-01

    MOCVD has been associated with batch processing of III-V opto-electronic devices for decades, with epitaxial structures deposited on up to 200 mm diameter wafers. Recent development in thin film PV has seen the gap in conversion efficiencies closing in on that of the commonly found multicrystalline Si wafer based PV. To further improve the conversion efficiency of thin film PV towards the theoretical limits of single junction solar cells requires a technique such as MOCVD with scalability potential. Preliminary results on the development of a chamberless inline process are reported for up to 15 cm wide float glass, progressively coating each layer in the CdTe solar cell as the heated substrate passes under each coating head in turn and entirely at atmospheric pressure. Emphasis is made on ensuring that the chamberless coating heads can be operated safely using a combination of nitrogen curtain flows and a balanced exhaust pressure system. Results are also presented on the exclusion of oxygen and moisture from the coating area, achieved using the same gas flow isolation process. This paper also reviews the achievements made to-date in the transfer of the high efficiency batch MOCVD produced CdTe solar cell to the chamberless inline process demonstrating device quality thin films deposition.

  19. Recent progress in MOCVD growth for thermoelectrically cooled HgCdTe medium wavelength infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Gawron, W.; Martyniuk, P.; Kębłowski, A.; Kolwas, K.; Stępień, D.; Piotrowski, J.; Madejczyk, P.; Pędzińska, M.; Rogalski, A.

    2016-04-01

    The authors report on advanced metalorganic chemical vapour deposition (MOCVD) of Hg1-xCdxTe (HgCdTe) structures for high operating temperature, medium wavelength infrared (MWIR) detector application. MOCVD technology with wide range of composition and donor/acceptor doping and without post grown annealing was proved to be an excellent tool for HgCdTe heterostructure epitaxial growth used for uncooled photodetector design. The interdiffused multilayer process (IMP) technique was applied for the HgCdTe deposition. HgCdTe epilayers were grown at 350 °C with Hg source kept at 210 °C. The II/VI mole ratio was assumed in the range from 1.5 to 3 during CdTe/HgTe cycles of the IMP process. The MWIR detectors grown by MOCVD exhibit detectivity ∼7.3 × 1011 Jones at λPEAK = 3.5 μm and T = 230 K being determined by background limited photodetector (BLIP) condition.

  20. Progress in MOCVD growth of HgCdTe epilayers for HOT infrared detectors

    NASA Astrophysics Data System (ADS)

    Kebłowski, A.; Gawron, W.; Martyniuk, P.; Stepień, D.; Kolwas, K.; Piotrowski, J.; Madejczyk, P.; Kopytko, M.; Piotrowski, A.; Rogalski, A.

    2016-05-01

    In this paper we present progress in MOCVD growth of (100) HgCdTe epilayers achieved recently at the Institute of Applied Physics, Military University of Technology and Vigo System S.A. It is shown that MOCVD technology is an excellent tool in fabrication of different HgCdTe detector structures with a wide range of composition, donor/acceptor doping and without post grown annealing. Particular progress has been achieved in the growth of (100) HgCdTe epilayers for long wavelength infrared photoconductors operated in HOT conditions. The (100) HgCdTe photoconductor optimized for 13-μm attain detectivity equal to 6.5x109 Jones and therefore outperform its (111) counterpart. The paper also presents technological progress in fabrication of MOCVD-grown (111) HgCdTe barrier detectors. The barrier device performance is comparable with state-of-the-art of HgCdTe photodiodes. The detectivity of HgCdTe detectors is close to the value marked HgCdTe photodiodes. Dark current densities are close to the values given by "Rule 07".

  1. Vortex-assisted liquid-liquid extraction combined with field-amplified sample injection and sweeping micellar electrokinetic chromatography for improved determination of β-blockers in human urine.

    PubMed

    Jouyban, Abolghasem; Sorouraddin, Mohammad Hossein; Farajzadeh, Mir Ali; Somi, Mohammad Hossein; Fazeli-Bakhtiyari, Rana

    2016-01-01

    A new micellar electrokinetic chromatography (MEKC) method was developed and validated for the analysis of carvedilol and propranolol in human urine samples. In this study, vortex-assisted liquid-liquid extraction (VALLE) coupled with field-amplified sample injection and sweeping was employed for biological sample clean-up and sensitivity enhancement in MEKC. After VALLE, the urine samples were analyzed by MEKC. Tris-phosphate buffer (60mmolL(-1), pH 2.0) containing 40% (v/v) methanol was first filled into an uncoated fused-silica capillary (56cm, 50µm i.d.). The pretreated urine sample was loaded by electrokinetic injection (10kV, 250s). The stacking and separation were performed using Tris-phosphate buffer (30mmolL(-1), pH 3.0) containing 30% (v/v) methanol and 50mmolL(-1) sodium dodecyl sulfate (SDS) at -25kV. Detection was carried out at 195 and 214nm for carvedilol and propranolol, respectively. The suggested method is linear (r(2)≥0.997) over a dynamic range of 0.005-1µgmL(-1) in urine. The intra- and inter-day relative standard deviation and relative error values of the method were below 20%, which shows good precision and accuracy. Finally, this method was successfully applied to the analysis of real urine samples.

  2. Dispersive liquid-liquid microextraction based on solidification of floating organic drop combined with field-amplified sample injection in capillary electrophoresis for the determination of beta(2)-agonists in bovine urine.

    PubMed

    Us, Murat Faruk; Alshana, Usama; Lubbad, Ibrahim; Göğer, Nilgün G; Ertaş, Nusret

    2013-03-01

    Dispersive liquid-liquid microextraction based on solidification of floating organic drop (DLLME-SFO) was for the first time combined with field-amplified sample injection (FASI) in CE to determine four β(2)-agonists (cimbuterol, clenbuterol, mabuterol, and mapenterol) in bovine urine. Optimum BGE consisted of 20 mM borate buffer and 0.1 mM SDS. Using salting-out extraction, β(2)-agonists were extracted into ACN that was then used as the disperser solvent in DLLME-SFO. Optimum DLLME-SFO conditions were: 1.0 mL ACN, 50 μL 1-undecanol (extraction solvent), total extraction time 1.5 min, no salt addition. Back extraction into an aqueous solution (pH 2.0) facilitated direct injection of β(2)-agonists into CE. Compared to conventional CZE, DLLME-SFO-FASI-CE achieved sensitivity enhancement factors of 41-1046 resulting in LODs in the range of 1.80-37.0 μg L(-1). Linear dynamic ranges of 0.15-10.0 mg L(-1) for cimbuterol and 15-1000 μg L(-1) for the other analytes were obtained with coefficients of determination (R(2)) ≥ 0.9901 and RSD% ≤5.5 (n = 5). Finally, the applicability of the proposed method was successfully confirmed by determination of the four β(2)-agonists in spiked bovine urine samples and accuracy higher than 96.0% was obtained.

  3. Effect of the structures of ionic liquids and alkylbenzene-derived amphiphiles on the inhibition of asphaltene precipitation from CO2-injected reservoir oils.

    PubMed

    Hu, Yu-Feng; Guo, Tian-Min

    2005-08-30

    The inhibition of asphaltene precipitation from high-pressure, CO(2)-injected reservoir oils by ionic and nonionic amphiphiles, the ionic liquids based on p-alkylpyridinium ([C(n)()py](+)) and N-butylisoquinolinium ([C(4)iql](+)) cations, and the alkylbenzene-derived amphiphiles p-alkylphenol (C(n)()phol), p-alkylbenzenesulfonic acid (C(n)()bsa), and sodium p-alkylbenzenesulfonate (C(n)()bsNa) was investigated for the first time. The influences of the structures of these compounds and the effect of the combination of their cations and anions were studied. The results show that the inhibition abilities of the alkylbenzene-derived amphiphiles first increase when n = 2-8 and then remain almost constant when n >/=8 and that the effectiveness follows the order C(n)()phol < C(n)()bsa approximately C(n)()bsNa. The inverse trend is observed for the ionic liquids [C(n)()py][Cl]; that is, their inhibition abilities decrease as n increases from 4 to 8 to 12. [C(4)iql][Cl] is more effective than [C(4)py][Cl], but [C(n)()py][BF(4)] and [C(n)()py][PF(6)] have almost no effect on the stabilization of asphaltenes. It was found that the effectiveness of an alkylbenzene-derived amphiphile on the inhibition of asphaltene precipitation from reservoir oils relies on its ability to form a stable steric-stabilization layer around asphaltenes, which is controlled by the polarity of its headgroup and the length of its alkyl tail. The novel mechanism of inhibiting asphaltene precipitation using the ionic liquids [C(n)()py] ([Cl], [BF(4)], and [PF(6)]) and [C(4)iql][Cl] was proposed. The mechanism states that the ionic liquids can effectively prevent asphaltene precipitation from the reservoir oils by breaking the asphaltene associations, which are due to the local nonneutrality of the charge densities of the cation and the anion. The ionic liquids that are based on an anion with high charge density, in connection with cations with sufficiently low charge densities, can effectively inhibit

  4. Screening for multiple phosphodiesterase type 5 inhibitor drugs in dietary supplement materials by flow injection mass spectrometry and their quantification by liquid chromatography tandem mass spectrometry.

    PubMed

    Song, Fenhong; El-Demerdash, Aref; Lee, Shwn-Ji Susie H

    2012-11-01

    A flow injection tandem mass spectrometry method (FI-MS/MS) has been developed to detect enzyme phosphodiesterase type 5 inhibitors, including tadalafil, sildenafil, and vardenafil. Multiple reaction monitoring (MRM) was used to detect the drugs and product ion ratios were used for identification. FI-MS/MS was used for semi-quantification and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for further confirmation and quantification. One of 13 samples has been found to be adulterated with prescription levels of tadalafil and also low level of sildenafil. The method can be used for screening large numbers of herbal products for adulteration since it takes less than 1 min without chromatographic separation on a column.

  5. Simultaneous enantioselective quantification of fluoxetine and norfluoxetine in human milk by direct sample injection using 2-dimensional liquid chromatography-tandem mass spectrometry.

    PubMed

    Alvim-Jr, Joel; Lopes, Bianca Rebelo; Cass, Quezia Bezerra

    2016-06-17

    A two-dimensional liquid chromatography system coupled to triple quadrupole tandem mass spectrometer (2D LC-MS/MS) was employed for the simultaneously quantification of fluoxetine (FLX) and norfluoxetine (NFLX) enantiomers in human milk by direct injection of samples. A restricted access media of bovine serum albumin octadecyl column (RAM-BSAC18) was used in the first dimension for the milk proteins depletion, while an antibiotic-based chiral column was used in the second dimension. The results herein described show good selectivity, extraction efficiency, accuracy, and precision with limits of quantification in the order of 7.5ngmL(-1)for the FLX enantiomers and 10.0ngmL(-1) for NFLX enantiomers. Furthermore, it represents a practical tool in terms of sustainability for the sample preparation of such a difficult matrix.

  6. Direct large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry determination of artificial sweeteners sucralose and acesulfame in well water.

    PubMed

    Wu, Minghuo; Qian, Yichao; Boyd, Jessica M; Hrudey, Steve E; Le, X Chris; Li, Xing-Fang

    2014-09-12

    Acesulfame (ACE) and sucralose (SUC) have become recognized as ideal domestic wastewater contamination indicators. Liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis is commonly used; however, the sensitivity of SUC is more than two orders of magnitude lower than that of ACE, limiting the routine monitoring of SUC. To address this issue, we examined the ESI behavior of both ACE and SUC under various conditions. ACE is ionic in aqueous solution and efficiently produces simple [M-H](-) ions, but SUC produces multiple adduct ions, limiting its sensitivity. The formic acid (FA) adducts of SUC [M+HCOO](-) are sensitively and reproducibly generated under the LC-MS conditions. When [M+HCOO](-) is used as the precursor ion for SUC detection, the sensitivity increases approximately 20-fold compared to when [M-H](-) is the precursor ion. To further improve the limit of detection (LOD), we integrated the large volume injection approach (500μL injection) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), which reduced the method detection limit (MDL) to 0.2ng/L for ACE and 5ng/L for SUC. To demonstrate the applicability of this method, we analyzed 100 well water samples collected in Alberta. ACE was detected in 24 wells at concentrations of 1-1534ng/L and SUC in 8 wells at concentrations of 65-541ng/L. These results suggest that wastewater is the most likely source of ACE and SUC impacts in these wells, suggesting the need for monitoring the quality of domestic well water.

  7. Characterization of metabolites in rats after intravenous administration of salvianolic acid for injection by ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry.

    PubMed

    Miao, Jingzhuo; Sun, Wanyang; Huang, Jingyi; Liu, Xiaolin; Li, Shuming; Han, Xiaoping; Tong, Ling; Sun, Guoxiang

    2016-09-01

    It is an essential requirement to clarify the metabolites of traditional Chinese medicine (TCM) injections, which contain numerous ingredients, to assess their safe and effective use in clinic. Salvianolic acid for injection (SAFI), made from hydrophilic phenolic acids in Salvia miltiorrhiza Bunge, has been widely used for the treatment of cerebrovascular diseases, but information on its metabolites in vivo is still lacking. In the present study, we aimed to holistically characterize the metabolites of the main active ingredients in rat plasma, bile, urine and feces following intravenous administration of SAFI. An ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method was developed. Combining information on retention behaviors, multistage mass spectra and literature data, a total of eight prototypes and 52 metabolites were tentatively characterized. Metabolites originated from rosmarinic acid and salvianolic acid B comprised the majority of identified compounds. Meanwhile, four metabolites derived from salvianolic acid D and five from salvianolic acid B are reported for the first time. This study revealed that methylation, sulfation and glucuronidation were the major metabolic pathways of phenolic acids in SAFI in vivo. Furthermore, the developed UPLC/Q-TOF-MS method could also benefit the metabolic investigation of extracts and preparations in TCM with hydrophilic ingredients. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Direct aqueous injection-liquid chromatography with post-column derivatization for determination of N-methylcarbamoyloximes and N-methylcarbamates in finished drinking water: collaborative study.

    PubMed

    Edgell, K W; Biederman, L A; Longbottom, J E

    1991-01-01

    An interlaboratory method validation study was conducted on EPA Method 531.1, Measurement of N-Methylcarbamoyloximes and N-Methylcarbamates in Water by Direct Aqueous Injection HPLC with Post Column Derivatization, to determine the precision and mean recovery for determination of 10 carbamate pesticide compounds in reagent water and in finished drinking waters. The study design was based on Youden's nonreplicate plan for collaborative tests of analytical methods. The waters were spiked with 10 carbamate pesticides at 6 concentration levels, as 3 Youden pairs. Eight laboratories analyzed the samples by direct aqueous injection, with separation by reverse-phase liquid chromatography and post-column hydrolysis of the carbamates and carbamoyloximes to methylamine, followed by reaction of the methylamine with o-phthalaldehyde and 2-mercaptoethanol using fluorescence detection. Results were analyzed using an EPA computer program, which measured precision and recovery for each of the 10 compounds and compared the performance of the method between water types. The method was acceptable for all analytes tested. After removal of a nonrepresentative data set for aldicarb sulfoxide, no matrix effects were observed; the statistics for the pooled drinking waters were not significantly different from the statistics for the reagent waters. The method has been adopted official first action by AOAC.

  9. Multisyringe flow injection analysis hyphenated with liquid core waveguides for the development of cleaner spectroscopic analytical methods: improved determination of chloride in waters.

    PubMed

    Maya, Fernando; Estela, José Manuel; Cerdà, Víctor

    2009-07-01

    In this work, the hyphenation of the multisyringe flow injection analysis technique with a 100-cm-long pathlength liquid core waveguide has been accomplished. The Cl-/Hg(SCN)2/Fe3+ reaction system for the spectrophotometric determination of chloride (Cl(-)) in waters was used as chemical model. As a result, this classic analytical methodology has been improved, minimizing dramatically the consumption of reagents, in particular, that of the highly biotoxic chemical Hg(SCN)2. The proposed method features a linear dynamic range composed of two steps between (1) 0.2-2 and (2) 2-8 mg Cl- L(-1), thus extended applicability due to on-line sample dilution (up to 400 mg Cl- L(-1)). It also presents improved limits of detection and quantification of 0.06 and 0.20 mg Cl- L(-1), respectively. The coefficient of variation and the injection throughput were 1.3% (n = 10, 2 mg Cl- L(-1)) and 21 h(-1). Furthermore, a very low consumption of reagents per Cl- determination of 0.2 microg Hg(II) and 28 microg Fe3+ has been achieved. The method was successfully applied to the determination of Cl- in different types of water samples. Finally, the proposed system is critically compared from a green analytical chemistry point of view against other flow systems for the same purpose.

  10. On-line liquid chromatography-mass spectrometry with dilution line to achieve large volume urine injection for the improvement of sensitivity.

    PubMed

    Liu, Min; Yan, Wei; Lin, Jin-Ming; Hashi, Yuki; Liu, Li-Bin; Wei, Yanlin

    2008-07-11

    A unique automated on-line high-performance liquid chromatography-mass spectrometry (LC-MS) method was developed allowing injection of a large volume of urine for the improvement of sensitivity using estrogens as analytes. The urine sample was precipitated by acetonitrile (sample:acetonitrile, 1:2, v/v) to remove most proteins. Then the supernatant was directly delivered at 0.3 mL/min by a pump, which broke through the limit of autosampler with fixed loop. Then the sample was loaded onto a restricted access media (RAM) pre-column after on-line dilution with NH(4)Ac solution which was delivered by another pump under high flow-rate. After the addition of on-line dilution line, the content of organic solvent in the sample aliquot was sharply decreased so that the analytes were effectively trapped by pre-column. In addition, another 6-port valve was added to selectively deliver the effluent containing analytes into MS, which minimized the pollution of the MS and matrix effect. After optimization of the condition of extraction method, 3 mL sample (containing 1 mL urine) could be successfully enriched. The injection volume increased 10 times compared with conventional on-line LC-MS methods for biofluid analysis, significantly improving sensitivity. Moreover, no obvious increase of column pressure was observed after 300 injections. The method was validated by spiking urine. Linearity was determined by sample which was in the range of 1-500 ng/mL. The process efficiency ranged from 70.2 to 106% with RSDs less than 15% with the exception of a few analytes. The limit of detection (LOD) and quantification (LOQ) ranged from 0.3 to 2 ng/mL and 1 to 8 ng/mL, respectively, corresponding a decrease of 1-2 orders of magnitude compared with those of off-line and on-line methods.

  11. Trace analysis of isothiazolinones in water samples by large-volume direct injection liquid chromatography tandem mass spectrometry.

    PubMed

    Speksnijder, P; van Ravestijn, J; de Voogt, P

    2010-08-06

    Isothiazolinones are used as preservatives, biocides and disinfectants in a variety of industrial and domestic applications. Some of the isothiazolinones are difficult to isolate from water due their high polarity. A sensitive and selective analytical method was developed and optimized for the determination of sub-microg/L levels of three isothiazolinones in water samples. Three isothiazolinones are described in this paper: 2-methyl-3-isothiazolinone, 5-chloro-2-methyl-3-isothiazolinone and 4,5-dichloro-2-methyl-3-isothiazolinone. The analytical method involves a robust large-volume direct on-column loop injection of 2 mL on an Aqua ODS HPLC column and tandem MS detection (HPLC-MS/MS). After filtration, samples are directly injected without further pretreatment. Detection limits of the individual target compounds were between 0.03 and 0.1 microg/L employing Multi-Reaction Monitoring (MRM) mass spectrometry. Based on the constant ratio of two selected product-ions together with the retention time, the identification is very selective and quantification is reliable. The method was successfully applied to real samples of membrane flushings, drinking water, surface waters and waste water. Additional investigations showed the instability of the isothiazolinones in river- and waste water. Preservation of river water and waste water samples with sodium azide (NaN(3)) promotes the stability of the isothiazolines in solution. In membrane flushings, waste water, surface waters and drinking water, levels of the three isothiazolinones were all below the limit of detection. In effluents of households containing washings from normal shampoo use, isothiazolinones could be detected.

  12. Micro liquid-liquid extraction combined with large-volume injection gas chromatography-mass spectrometry for the determination of haloacetaldehydes in treated water.

    PubMed

    Serrano, María; Silva, Manuel; Gallego, Mercedes

    2011-11-18

    Haloacetaldehydes (HAs) are becoming the most widespread disinfection by-products (DBPs) found in drinking water, besides trihalomethanes and haloacetic acids, generated by the interaction of chemical disinfectants with organic matter naturally present in water. Because of their high potential toxicity, HAs have currently received a singular attention, especially trichloroacetaldehyde (chloral hydrate, CH), the most common and abundant compound found in treated water. The aims of this study are focused on the miniaturisation of EPA Method 551.1, including some innovations such as the use of ethyl acetate as the extracting solvent, the enhancement of HAs stability in aqueous solutions by adjusting the pH ~3.2 and the use of a large-volume sample injection (30 μL) coupled to programmed temperature vaporizer-gas chromatography-mass spectrometry to improve both sensitivity and selectivity. In optimised experimental conditions, the limits of detection for the 7 HAs studied ranged from 6 to 20 ng/L. Swimming pools have recently been recognized as an important source of exposure to DBPs and as a result, in this research for the first time, HAs have been determined in this type of water. Two HAs have been found in the analysed water: CH at concentrations between 1.2-38 and 53-340 μg/L and dichloroacetaldehyde between 0.07-4.0 and 1.8-23 μg/L in tap and swimming pool waters, respectively.

  13. Heat transfer coefficients over a flat surface with air and CO{sub 2} injection through compound angle holes using a transient liquid crystal image method

    SciTech Connect

    Ekkad, S.V.; Zapata, D.; Han, J.C.

    1997-07-01

    This paper presents the detailed heat transfer coefficients over a flat surface with one row of injection holes inclined streamwise at 35 deg for three blowing ratios (M = 0.5--2.0). Three compound angles of 0, 45, and 90 deg with air (D.R. = 0.98) and CO{sub 2} (D.R. = 1.46) as coolants were tested at an elevated free-stream turbulence condition (Tu {approx} 8.5%). The experimental technique involves a liquid crystal coating on the test surface. Two related transient tests obtained detailed heat transfer coefficients and film effectiveness distributions. Heat transfer coefficients increase with increasing blowing ratio for a constant density ratio, but decrease with increasing density ratio for a constant blowing ratio. Heat transfer coefficients increase for both coolants over the test surface as the compound angle increases from 0 to 90 deg. The detailed heat transfer coefficients obtained using the transient liquid crystal technique, particularly in the near-hole region, will provide a better understanding of the film cooling process in gas turbine components.

  14. Determination of free and total vincristine in human plasma after intravenous administration of vincristine sulfate liposome injection using ultra-high performance liquid chromatography tandem mass spectrometry.

    PubMed

    Yang, Fen; Wang, Hongyun; Liu, Ming; Hu, Pei; Jiang, Ji

    2013-02-01

    Vincristine sulfate liposome is a liposomal formulation of vincristine sulfate, a traditional anticancer drug, encapsulated in the aqueous core of phospholipid/cholesterol liposomes, which are kinds of targeted carriers to enhance malignancy targeting, exposure and anticancer activity of the drug. To evaluate and compare the pharmacokinetics of nonliposomal and liposome-encapsulated VCR and pharmacodynamic relationships associated with the toxicity and the efficacy behavior, it is essential to have a reliable method of separating the free and liposomal forms of the drug. In this paper, we have developed and validated methods to quantify the free vincristine (F-VCR) and total vincristine (T-VCR) in human plasma after intravenous administration of vincristine sulfate liposome injection (VSLI). The methods involve solid-phase extraction (SPE) for separating the F-VCR and liquid-liquid extraction (LLE) for releasing the VCR totally from the liposomal forms followed by an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode using positive electrospray ionization (ESI). The methods were validated over the concentration range of 0.2-50 ng/mL for F-VCR and 0.5-400 ng/mL for T-VCR, respectively. Inter- and intra-day precision (RSD%) were ≤4.7% for F-VCR and ≤9.8% for T-VCR, respectively. The accuracies were between -2.3 and 9.1% for F-VCR and between -3.2 and 6.9% for T-VCR, respectively. The extraction recovery and the matrix effect were investigated. The methods were successfully applied to the pharmacokinetic study of VSLI in Chinese subjects with lymphoma.

  15. Thermal equilibrium and prehydration processes of electrons injected into liquid water calculated by dynamic Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Kai, Takeshi; Yokoya, Akinari; Ukai, Masatoshi; Fujii, Kentaro; Watanabe, Ritsuko

    2015-10-01

    The thermalization length and spatial distribution of electrons in liquid water were simulated for initial electron energies ranging from 0.1 eV to 100 keV using a dynamic Monte Carlo code. The results showed that electrons were decelerated for thermalization over a longer time period than was previously predicted. This long thermalization time significantly contributed to the series of processes from initial ionization to hydration. We further studied the particular deceleration process of electrons at an incident energy of 1 eV, focusing on the temporal evolution of total track length, mean traveling distance, and energy distributions of decelerating electrons. The initial prehydration time and thermalization periods were estimated to be approximately 50 and 220 fs, respectively, indicating that the initial prehydration began before or contemporaneously with the thermal equilibrium. Based on these results, the prehydrated electrons were suggested to play an important role during multiple DNA damage induction.

  16. Clinical efficacy of a centric relation occlusal splint and intra-articular liquid phase concentrated growth factor injection for the treatment of temporomandibular disorders

    PubMed Central

    Yang, Jung-Wu; Huang, Yi-Chia; Wu, Shang-Liang; Ko, Shun-Yao; Tsai, Chiang-Chin

    2017-01-01

    Abstract The agony that accompanies the incidence and symptoms of temporomandibular disorders (TMDs) is an important concern in the oral and maxillofacial region. The objective of this study was to explore the clinical findings after centric relation occlusal splint (CROS) treatment and intra-articular injection treatment with liquid phase concentrated growth factors (LPCGFs) in patients with disc displacement without reduction (DDWOR). The group under investigation of this retrospective cohort study included patients with DDWOR who received treatment from April 2014 until March 2016. The predictor variable was the therapeutic method. The outcome variables included joint crepitus sound, visual analog scale (VAS) of temporomandibular joint (TMJ) arthralgia, TMD-associated headache, myofascial pain with referral, deviation of the mandible during opening (DoM), and maximal interincisal opening (MIO). At the stage of CROS treatment, evaluation of all variables adopted the individual as the unit; at the stage after LPCGF injection, the evaluation of joint sound adopted the joint as the unit, whereas the other variables adopted the individual as the unit. Among the 29 patients, 6 (20.68%) were males and 23 (79.31%) were females. Distribution by age ranged from 15 to 84 years (mean age 39.55 ± 15.49 years). After CROS treatment, except for the joint crepitus sound, which failed to achieve significant improvement (P > 0.05), other symptoms, such as DOM, TMD-associated headache, myofascial pain with referral, TMJ arthralgia, and MIO, all achieved statistically significant improvements (P < 0.05). After 2 mL of LPCGF was injected once after CROS treatment, 26 joint crepitus sound symptoms were relieved (P < 0.001) after an average of 48.5 ± 64.1 days. CROS alone can alleviate TMD clinical symptoms, except for the joint crepitus sound. Approximately 72.2% of joint crepitus sounds could be improved within 48 days, on average, once 2 mL of LPCGF was

  17. Development of a sequential injection dispersive liquid-liquid microextraction system for electrothermal atomic absorption spectrometry by using a hydrophobic sorbent material: determination of lead and cadmium in natural waters.

    PubMed

    Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

    2010-05-23

    A novel on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system coupled to electrothermal atomic absorption spectrometry (ETAAS) was developed for metal preconcentration in micro-scale, eliminating the laborious and time consuming procedure of phase separation with centrifugation. The potentials of the system were demonstrated for trace lead and cadmium determination in water samples. An appropriate disperser solution which contains the extraction solvent (xylene) and the chelating agent (ammonium pyrrolidine dithiocarbamate) in methanol is mixed on-line with the sample solution (aqueous phase), resulting thus, a cloudy solution, which is consisted of fine droplets of xylene, dispersed throughout the aqueous phase. Three procedures are taking place simultaneously: cloudy solution creation, analyte complex formation and extraction from aqueous phase into the fine droplets of xylene. Subsequently the droplets were retained on the hydrophobic surface of PTFE-turnings into the column. A part of 30 microL of the eluent (methyl isobutyl ketone) was injected into furnace graphite for analyte atomization and quantification. The sampling frequency was 10 h(-1), and the obtained enrichment factor was 80 for lead and 34 for cadmium. The detection limit was 10 ng L(-1) and 2 ng L(-1), while the precision expressed as relative standard deviation (RSD) was 3.8% (at 0.5 microg L(-1)) and 4.1% (at 0.03 microg L(-1)) for lead and cadmium respectively. The proposed method was evaluated by analyzing certified reference materials and was applied to the analysis of natural waters.

  18. Effects of ionic liquid and nanogold particles on high-performance liquid chromatography-electrochemical detection and their application in highly efficient separation and sensitive analysis of five phenolic acids in Xuebijing injection.

    PubMed

    Jia, Pu; Wang, Shixiang; Meng, Xue; Lan, Wei; Luo, Jing; Liao, Sha; Xiao, Chaoni; Zheng, Xiaopu; Li, Lianshe; Liu, Qinshe; Zheng, Jianbin; Zhou, Yuanzhen; Zheng, Xiaohui

    2013-03-30

    A novel high performance liquid chromatography-electrochemical detector (HPLC-ECD) analytical system was developed in this study by integratedly utilizing ionic liquid (IL) of 1-butyl-3-methylimidazolium bromide and an additive of gold nanoparticles. The resulted pilot study was first performed to assess the effects of 1-butyl-3-methylimidazolium bromide and gold nanoparticles on the chromatographic characteristics of five phenolic acids in Xuebijing injection, including danshensu (DSS), protocatechuic acid (PA), protocatechuic aldehyde (PAH), hydroxy safflower yellow A (HSYA) and ferulic acid (FA). It was notable to observe that retainability of the phenolic acids were markly lowered by IL addition. Compared with the cases without IL addition, the retention times of DSS, PA, PAH, HSYA and FA have decreased 2.851, 1.532, 1.53, 0.818 and 0.552 min, respectively when 0.6% IL in the mobile phase. In addition, the corresponding theoretical plate numbers and peak areas for these compounds were significantly increased. Area response for DSS, PA, PAH, HSYA and FA were enhanced by 772%, 628%, 584%, 703% and 600%, respectively. It was observed that nano-gold catalysis power enabled peak areas of DSS, PAH, FA and PA to enhance 5.7, 6.2, 8.5 and 66.5 times relative to the case with addition of IL. Altogether, the optimized HPLC-ECD system was successfully applied to the pharmacokinetics study of Xuebijing injection with underlying applicability to in vivo and in vitro analysis of a variety of natural product from Chinese medicine plants, TCM formulae and associated patent TCM preparation.

  19. Simultaneous determination of fluoroquinolones in environmental water by liquid chromatography-tandem mass spectrometry with direct injection: A green approach.

    PubMed

    Denadai, Marina; Cass, Quezia Bezerra

    2015-10-30

    This work describes an on-line multi-residue method for simultaneous quantification of ciprofloxacin, enrofloxacin, gemifloxacin, moxifloxacin, norfloxacin and ofloxacin in superficial and wastewater samples. For that, an octyl restricted-access media bovine serum albumin column (RAM-BSA C8) was used for sample clean-up, enrichment and analysis with quantitation carried out by tandem mass spectrometry. For water samples volumes of only 500μL the method provided good selectivity, extraction efficiency, accuracy, and precision with quantification limits in the order of 20-150ngL(-1). Out of the six fluoroquinolones only ciprofloxacin (195ngL(-1)) and norfloxacin (270ngL(-1)) were quantified in an influent sample of the wastewater treatment plant (WWTP) of São Carlos (SP, Brazil). None were found in the superficial water samples analyzed. The capability of injecting native sample in an automated mode provides high productivity and represents a greener approach in environmental sample analysis.

  20. Electron and Composite Fermion Transport in MOCVD Grown GaAs/AlGaAs Heterostructures

    NASA Astrophysics Data System (ADS)

    Zudov, M. A.; Du, R. R.; Simmons, J. A.; Chui, H. C.

    1996-03-01

    Previously, high quality fractional quantum Hall effect(FQHE) data was accessible only from MBE-grown heterostructures. Sandia National Labs has recently grown high purity MOCVD GaAs/AlGaAs heterostructure with 2DEG mobility of 2.0x10^6 cm^2/Vs[1]. Material parameters such as impurity potential profile, defects and interface quality are expected to be modified for MOCVD. While these are believed to affect predominantly the carrier scattering in 2DEG, their effects on quantum transport properties (in particular the experimental effective mass and spin g-factor of composite fermions) are also worth examination. We report on temperature-dependent Shubnikov -de Haas(SdH) oscillations near zero magnetic field, SdH near Landau level filling factor ν = 1/2, 3/2, and angular dependent magnetoresistance mesurements on the FQHE states around ν = 3/2 in high-density (up to 3.2x10^11 cm-2) MOCVD samples. Measurements were performed in a 20mK/20T ^3He-^4He mixture dilution refrigerator. Our results around ν = 3/2 conform to the same composite fermion level scheme obtained earlier for low-density MBE samples[2]. [1] H. C. Chui, B. E. Hammons, N. E. Harff, J. A. Simmons and M. E. Sherwin, to appear in Appl. Phys. Lett. [2] R. R. Du, A. S. Yeh, H. L. Stormer, D. C. Tsui, L. N. Pfeifer, K. W. West, Phys. Rev. Lett. 75, 3926(1995)

  1. Fully Automatic In-Syringe Magnetic Stirring-Assisted Dispersive Liquid-Liquid Microextraction Hyphenated to High-Temperature Torch Integrated Sample Introduction System-Inductively Coupled Plasma Spectrometer with Direct Injection of the Organic Phase.

    PubMed

    Sánchez, Raquel; Horstkotte, Burkhard; Fikarová, Kateřina; Sklenářová, Hana; Maestre, Salvador; Miró, Manuel; Todolí, Jose-Luis

    2017-03-21

    A proof of concept study involving the online coupling of automatic dispersive liquid-liquid microextraction (DLLME) to inductively coupled plasma optical emission spectrometry (ICP OES) with direct introduction and analysis of the organic extract is herein reported for the first time. The flow-based analyzer features a lab-in-syringe (LIS) setup with an integrated stirring system, a Meinhard nebulizer in combination with a heated single-pass spray chamber, and a rotary injection valve, used as an online interface between the microextraction system and the detection instrument. Air-segmented flow was used for delivery of a fraction of the nonwater miscible extraction phase, 12 μL of xylene, to the nebulizer. All sample preparative steps including magnetic stirring assisted DLLME were carried out inside the syringe void volume as a size-adaptable yet sealed mixing and extraction chamber. Determination of trace level concentrations of cadmium, copper, lead, and silver as model analytes has been demonstrated by microextraction as diethyldithiophosphate (DDTP) complexes. The automatic LIS-DLLME method features quantitative metal extraction, even in troublesome sample matrixes, such as seawater, salt, and fruit juices, with relative recoveries within the range of 94-103%, 93-100%, and 92-99%, respectively. Furthermore, no statistically significant differences at the 0.05 significance level were found between concentration values experimentally obtained and the certified values of two serum standard reference materials.

  2. Surface Science in an MOCVD Environment: Arsenic on Vicinal Ge(100)

    SciTech Connect

    McMahon, W. E.; Olson, J. M.

    1998-11-01

    Scanning tunneling microscope (STM) images of arsine-exposed vicinal Ge(100) surfaces show that most As/Ge steps are reconstructed, and that a variety of different step structures exist. The entire family of reconstructed As/Ge steps can be divided into two types, which we have chosen to call ''single-row'' steps and ''double-row'' steps. In this paper we propose a model for a double-row step created by annealing a vicinal Ge(100) substrate under an arsine flux in a metal-organic chemical vapor deposition (MOCVD) chamber.

  3. Gas phase adduct reactions in MOCVD growth of GaN

    SciTech Connect

    Thon, A.; Kuech, T.F.

    1996-11-01

    Gas phase reactions between trimethylgallium (TMG) and ammonia were studied at high temperatures, characteristic to MOCVD of GaN reactors, by means of in situ mass spectroscopy in a flow tube reactor. It is shown, that a very fast adduct formation followed by elimination of methane occurs. The decomposition of TMG and the adduct-derived compounds are both first order and have similar apparent activation energy. The pre-exponential factor of the adduct decomposition is smaller, and hence is responsible for the higher full decomposition temperature of the adduct relative to that of TMG.

  4. Simultaneous determination of ten biogenic amines in a thymopolypeptides injection using ultra-performance liquid chromatography coupled with electrospray ionization tandem quadrupole mass spectrometry.

    PubMed

    Li, Yong; Yang, Huaxin; Liao, Haiming; Fan, Huihong; Liang, Chenggang; Deng, Lijuan; Jin, Shaohong

    2013-06-15

    A selective and sensitive ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-MS) method was developed for the simultaneous determination of ten biogenic amines (tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, adrenaline, dopamine and spermine) in a thymopolypeptides injection from the Chinese market for the first time. Biogenic amines (BAs) were pre-column derivatised by dansyl chloride after direct sample dilution. Dansylated amines were separated on an ACQUITY UPLC BEH Shield RP18 column (2.1mm×150mm I.D., 1.7μm) using a gradient elution. Quantification was done by monitoring fragment ions of each derivative under the MS mode of multiple reaction monitoring (MRM). A satisfactory result of method validation was obtained. The linearity ranged from 0.32 to 1182.9μg/L and the correlation coefficients (r) for all amines were above 0.99. The LOD ranged from 0.08μg/L for 2-phenylethylamine and tyramine to 8.00μg/L for adrenaline; the LOQ ranged from 0.32μg/L for 2-phenylethylamine to 12.12μg/L for dopamine. The recovery ranged from 75.8 to 110.3% after spiking standard solutions of BAs to a sample at three levels. The intra and inter-day precision RSD were 0.78-8.85% and 1.39-9.93% respectively. Eighty-four injections were analyzed by this method. Nine biogenic amines were found in them except adrenaline. Moreover, the relationship between the result of test for depressor substances and the content of BAs was statistically analyzed.

  5. Quantitative determination of pioglitazone in human serum by direct-injection high-performance liquid chromatography mass spectrometry and its application to a bioequivalence study.

    PubMed

    Xue, Y-J; Turner, Kenneth C; Meeker, Jeff B; Pursley, Janice; Arnold, Mark; Unger, Steve

    2003-10-05

    A simple, high throughput, direct-injection high-performance liquid chromatography tandem mass spectrometry method (LC/MS/MS) has been developed and validated for the quantitation of pioglitazone in human serum. After mixing the internal standard with a sample, a 10 microl portion of the mixture was directly injected into a high-flow LC/MS/MS system, which included an extraction column, an analytical column and a six-port switching valve. The on-line extraction was achieved on an Oasis HLB column (1 mm x 50 mm, 30 microm) with a 100% aqueous loading mobile phase containing 5 mM ammonium acetate (pH 4.0) at a flow rate of 4 ml/min. The extracted analyte was eluted by a mobile phase which contained 5 mM ammonium acetate and acetonitrile. The analytical column was a Luna C18 column (4.6 mm x 50 mm, 5 microm). Detection was achieved by positive ion electrospray tandem mass spectrometry. The lower limit of quantitation of the method was 9 ng/ml. The standard curve, which ranged from 9 to 1350 ng/ml, was fitted by a weighted (1/x2) quadratic regression model. The validation results demonstrated that this method had satisfactory precision and accuracy across the calibration range. There was no evidence of instability of the analyte in human serum following three freeze-thaw cycles, and samples could be stored for at least 2 weeks at -30 degrees C. This method was used to analyze pioglitazone concentrations in human serum samples from a bioequivalence study of a blinded Actos formulation (encapsulated 15 mg tablet) and an Actos 15 mg tablet. The blinded formulation was shown to be bioequivalent to an Actos 15 mg tablet.

  6. Effects of liquid preservation of sperm on their ability to activate oocytes and initiate preimplantational development after intracytoplasmic sperm injection in the pig.

    PubMed

    Binh, N T; Van Thuan, N; Miyake, M

    2009-06-01

    The objective of this study was to clarify the effects of liquid preservation conditions on the ability of pig sperm to activate oocytes, form a male pronucleus, and initiate preimplantational development of embryos after intracytoplasmic sperm injection (ICSI). Porcine ejaculates were preserved at 4, 14, and 24 degrees C for up to 48h, and then damage to the plasma membrane, morphologic changes of the acrosome, and the amount of phospholipase Czeta (PLCzeta) in the sperm were assessed by SYBR-14/propidium iodide staining, fluorescein isothiocyanate-conjugated peanut agglutinin staining, indirect immunofluorescence, and Western blots, respectively. The proportion of sperm with a disintegrated plasma membrane or damaged acrosome increased in all samples as the duration of preservation increased, although the time courses of the increases varied among preservation temperatures. The immunolocalization and immunoreactivity of PLCzeta in the sperm showed its reduction concurrent with disintegration of the plasma membrane and acrosome. Rates of oocyte activation, male-pronuclear formation, and blastocyst formation after ICSI using sperm preserved for 18h at 24 degrees C (78%, 62%, and 35%, respectively) and for 48h at 14 degrees C (63%, 53%, and 28%, respectively) were significantly higher than those of any other sperm sample. We concluded that the damage to the plasma membrane and acrosome, and a sufficient amount of PLCzeta in the sperm head, enhanced successful oocyte activation, fertilization, and early development of the oocytes after ICSI. Moreover, we inferred that appropriate liquid preservation of sperm improved the efficiency of blastocyst production in vitro after ICSI in pigs.

  7. Gaseous Fuel Injection Modeling using a Gaseous Sphere Injection Methodology

    SciTech Connect

    Hessel, R P; Aceves, S M; Flowers, D L

    2006-03-06

    The growing interest in gaseous fuels (hydrogen and natural gas) for internal combustion engines calls for the development of computer models for simulation of gaseous fuel injection, air entrainment and the ensuing combustion. This paper introduces a new method for modeling the injection and air entrainment processes for gaseous fuels. The model uses a gaseous sphere injection methodology, similar to liquid droplet in injection techniques used for liquid fuel injection. In this paper, the model concept is introduced and model results are compared with correctly- and under-expanded experimental data.

  8. Improvements in MOCVD growth of Hg1-xCdxTe heterostructures for uncooled infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Piotrowski, A.; Gawron, W.; Klos, K.; Pawluczyk, J.; Piotrowski, J.; Madejczyk, P.; Rogalski, A.

    2005-09-01

    We report here the recent progress at VIGO/MUT (Military University of Technology) MOCVD Laboratory in the growth of Hg1-xCdxTe multilayer heterostructures for various types of uncooled infrared devices. The detectors are optimized for any wavelength within 1-12 μm spectral range. Hg1-xCdxTe growth with interdiffused multilayer process (IMP) technique has been improved. The total flow of the carrier gas was optimized to improve lateral uniformity of the composition and doping. The parasitic transient stages between the CdTe and HgTe phases were reduced to reasonable minimum. As a result, we were able to grow layers with homogeneous composition and doping, characterized by steep interfaces. The additional benefits were improved morphology, reduced dislocation density, and minimized consumption of precursors. The other issues addressed in this work were growth of heavy As-doped low-x and heavy Idoped high-x materials. Special modification to IMP process has been applied for in-situ control of stoichiometry. To maintain low vacancy concentration, special growth finish procedure has been developed. No post-growth thermal anneal was necessary for device-quality material. The MOCVD grown heterostructures have been successfully used for advanced uncooled infrared photodetectors such as multiple heterojunction photodiodes, multicolor and specially shaped spectral response multiabsorber devices.

  9. Fabrication of GaN nanotubular material using MOCVD with aluminum oxide membrane

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Gwang; Jung, Se-Hyuck; Kung, Patrick; Razeghi, Manijeh

    2006-02-01

    GaN nanotubular material is fabricated with aluminum oxide membrane in MOCVD. SEM, XRD, TEM and PL are employed to characterize the fabricated GaN nanotubular material. An aluminum oxide membrane with ordered nano holes is used as template. Gallium nitride is deposited at the inner wall of the nano holes in aluminum oxide template, and the nanotubular material with high aspect ratio is synthesized using the precursors of TMG and ammonia gas. Optimal synthesis condition in MOCVD is obtained successfully for the gallium nitride nanotubular material in this research. The diameter of GaN nanotube fabricated is approximately 200 ~ 250 nm and the wall thickness is about 40 ~ 50 nm. GaN nanotubular material consists of numerous fine GaN particulates with sizes ranging 15 to 30 nm. The composition of gallium nitride is confirmed to be stoichiometrically 1:1 for Ga and N by EDS. XRD and TEM analyses indicate that grains in GaN nanotubular material have nano-crystalline structure. No blue shift is found in the PL spectrum on the GaN nanotubular material fabricated in aluminum oxide template.

  10. Epitaxial Growth of BGaAs and BGaInAs by MOCVD: Preprint

    SciTech Connect

    Geisz, J. F.; Friedman, D. J.; Kurtz, S. R.; Olson, J. M.; Kramer, C.; Young, M.; Barber, G.; Swartzlander, A. B.; Reedy, R. C.; Norman, A. G.

    2001-10-01

    Presented at the 2001 NCPV Program Review Meeting: Comparison of use of TMB, TEB, and BF3 to diborane for MOCVD growth of BGaInAs. BGaInAs can potentially be used in strain-free high-efficiency III-V solar cells, but the growth of sufficiently high-quality epitaxial BGaInAs using diborane has proven difficult. We compare the use of alternative boron precursors (trimethylboron [TMB], triethylboron [TEB], and boron trifluoride [BF{sub 3}]) with diborane for the MOCVD growth of these boron-containing III-V alloys. We find that TMB and BF{sub 3} do not result in significant boron incorporation into GaAs. TEB does result in boron incorporation in a manner very similar to diborane. Both diborane and TEB incorporate more efficiently using triethylgallium (TEG) rather than trimethylgallium (TMG), making TEG a preferred source of gallium for BGaAs epitaxy. Using TEB together with TEG, a higher boron composition (x = 4%-7%) has been achieved than has been previously reported, but we are still unable to achieve high- quality BGaInAs with the correct composition for solar cell applications.

  11. Fabrication of GaN nanotubular material using MOCVD with an aluminium oxide membrane

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Gwang; Jung, Se-Hyuck; Kung, Patrick; Razeghi, Manijeh

    2006-01-01

    GaN nanotubular material is fabricated with an aluminium oxide membrane in MOCVD. SEM, XRD, TEM and PL are employed to characterize the fabricated GaN nanotubular material. An aluminium oxide membrane with ordered nanoholes is used as a template. Gallium nitride is deposited at the inner wall of the nanoholes in the aluminium oxide template, and the nanotubular material with high aspect ratio is synthesized using the precursors of TMG and ammonia gas. Optimal synthesis conditions in MOCVD are obtained successfully for the gallium nitride nanotubular material in this research. The diameter of the GaN nanotube fabricated is approximately 200-250 nm and the wall thickness is about 40-50 nm. GaN nanotubular material consists of numerous fine GaN particulates with size range 15-30 nm. The composition of gallium nitride is confirmed to be stoichiometrically 1:1 for Ga and N by EDS. XRD and TEM analyses indicate that the grains in GaN nanotubular material have a nano-crystalline structure. No blue shift is found in the PL spectrum on the GaN nanotubular material fabricated in an aluminium oxide template.

  12. Preservation and analytical procedures for the analysis of chloro-s-triazines and their chlorodegradate products in drinking waters using direct injection liquid chromatography tandem mass spectrometry.

    PubMed

    Smith, Glynda A; Pepich, Barry V; Munch, David J

    2008-08-22

    A direct injection, liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for the analysis of the chloro-s-triazine herbicides and their degradates in finished drinking water. The target compounds in the method were selected based on their inclusion in a common mechanism group (CMG) because of their ability to induce a similar toxic effect through a common mechanism of toxicity. The target list includes the chloro-s-triazines (atrazine, simazine, cyanazine, and propazine) and their dealkylated degradates (desethylatrazine, desisopropylatrazine, and diaminochlorotriazine). Potential matrix effects are minimized by the use of individual isotopically enriched internal standards. Analyte stability in finished chlorinated drinking water samples is ensured through careful selection of proper dechlorinating and antimicrobial reagents and through buffering sample pH. In the absence of proper dechlorination, the target analytes were found to degrade over a short period of time, even under refrigerated storage conditions. The final method has adequate sensitivity to accurately detect all target analytes at or below 0.1 microg/L and displays sufficient precision and robustness to warrant publication as EPA Method 536.

  13. Determination of pesticides in seaweeds by pressurized liquid extraction and programmed temperature vaporization-based large volume injection-gas chromatography-tandem mass spectrometry.

    PubMed

    García-Rodríguez, D; Carro-Díaz, A M; Lorenzo-Ferreira, R A; Cela-Torrijos, R

    2010-04-23

    A rapid method for the simultaneous identification and quantification of pesticide residues in edible seaweed has been developed. Target analytes were three pyrethroid, a carbamate and two organophosphorus pesticides. The procedure consists of a pressurized liquid extraction (PLE) with integrated clean-up, followed by gas chromatography coupled to tandem mass spectrometry. Five PLE parameters were investigated using a screening design: temperature, static extraction time, number of cycles, percent of flush volume and quantitative composition of the n-hexane/ethyl acetate extraction solvent. The effect of the in-cell clean-up with Florisil and graphitized carbon black adsorbents was investigated using a Doehlert response surface design. Large volumes of sample extracts were injected using a programmed-temperature vaporizer (PTV-LVI) to improve both sensitivity and selectivity of measurements. Quantification was carried by the internal standard method with surrogate deuterated standards. The method showed excellent linearity (R2>0.999) and precision (relative standard deviation, RSD < or = 8%) for all compounds, with detection limits ranging from 0.3 pg g(-1) for chlorpyrifos-ethyl, to 3.0 pg g(-1) for carbaryl (23.1 pg g(-1) for deltamethrin). Recoveries in real seaweed samples were within the range 82-108%. The method was satisfactory validated for the analysis of wild and cultivated edible seaweeds. The presence of pyrethroid and organophosphorus pesticides in some of the samples was evidenced.

  14. Analysis of iodinated haloacetic acids in drinking water by reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry with large volume direct aqueous injection.

    PubMed

    Li, Yongtao; Whitaker, Joshua S; McCarty, Christina L

    2012-07-06

    A large volume direct aqueous injection method was developed for the analysis of iodinated haloacetic acids in drinking water by using reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry in the negative ion mode. Both the external and internal standard calibration methods were studied for the analysis of monoiodoacetic acid, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid in drinking water. The use of a divert valve technique for the mobile phase solvent delay, along with isotopically labeled analogs used as internal standards, effectively reduced and compensated for the ionization suppression typically caused by coexisting common inorganic anions. Under the optimized method conditions, the mean absolute and relative recoveries resulting from the replicate fortified deionized water and chlorinated drinking water analyses were 83-107% with a relative standard deviation of 0.7-11.7% and 84-111% with a relative standard deviation of 0.8-12.1%, respectively. The method detection limits resulting from the external and internal standard calibrations, based on seven fortified deionized water replicates, were 0.7-2.3 ng/L and 0.5-1.9 ng/L, respectively.

  15. Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography-quadrupole-linear ion trap-mass spectrometry.

    PubMed

    Pareja, Lucía; Martínez-Bueno, M J; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, A R

    2011-07-29

    A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1).

  16. Waterflooding injectate design systems and methods

    DOEpatents

    Brady, Patrick V.; Krumhansl, James L.

    2016-12-13

    A method of recovering a liquid hydrocarbon using an injectate includes recovering the liquid hydrocarbon through primary extraction. Physico-chemical data representative of electrostatic interactions between the liquid hydrocarbon and the reservoir rock are measured. At least one additive of the injectate is selected based on the physico-chemical data. The method includes recovering the liquid hydrocarbon from the reservoir rock through secondary extraction using the injectate.

  17. Analyse par simulation numérique du développement de l'instabilité électro-convective d'une couche de liquide diélectrique infinie soumise à une injection unipolaire

    NASA Astrophysics Data System (ADS)

    Traoré, Philippe; Perez, A.; Koulova-Nenova, D.; Romat, H.

    2009-09-01

    In this article electroconvective phenomenon, which take place in a dielectric liquid layer submitted to an unipolar injection, are studied by numerical simulations means. For the first time the full and coupled resolution of the Electro-Hydro-Dynamic equations are achieved. The results are compared with those coming from stability analysis especially for the linear and non-linear criteria in strong and weak injection cases. The hysterical behavior of the development of this instability is accurately reproduced. To cite this article: P. Traoré et al., C. R. Mecanique 337 (2009).

  18. Beam-injection flame furnace AAS: comparison of different nozzle types for beam generation and application of sub-critical liquid carbon dioxide as carrier and gas pressure pump.

    PubMed

    Ratka, Annelen; Berndt, Harald

    2004-01-01

    In beam injection flame furnace AAS (BIFF-AAS) the sample is introduced as a free-flying high-speed liquid beam into an AAS flame-heated nickel tube, resulting in a considerable improvement in the power of detection. For optimization of beam generation different nozzle types (smooth jet nozzles, turbulent working nozzles) have been compared at different pressures. It was found that the type of the nozzle hardly influences the analytical signal. However, the flow rates resulting from the different inner diameters of the nozzles and the applied pressures led to drastic changes in the analytical signal. For these investigations a recently developed 0.6 MPa (84 psig) diaphragm pump system was used. Furthermore, for the first time ever sub-critical liquid carbon dioxide has been used simultaneously as a liquid gas-pressure pump, as carrier in a flow-injection system (FIA), and for the beam generation. Transport of the carrier takes place as a result of the head pressure (6 MPa) of the liquid CO2 in the gas cylinder. For volatile elements (e.g. Cd, Hg, Pb, and Tl) detection limits between 0.2 microg L(-1) (Cd) and 28 microg L(-1) (Hg) were found, the standard deviation was from 0.6% to 3.2% depending on the element, concentration, and sample volume used. The use of liquid CO2 as a carrier in FIA systems opens up new possibilities for online sample pretreatment and trace preconcentration.

  19. On-line UV-photooxidation with peroxodisulfate for automated flow injection and for high-performance liquid chromatography coupled to hydride generation atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Tsalev, Dimiter L.; Sperling, Michael; Welz, Bernhard

    2000-04-01

    An automated on-line UV photooxidation with peroxodisulfate of some environmentally relevant organoarsenic and organotin compounds in a system built from commercially available modules has been studied and optimised with a view to both species-independent quantification of the total arsenic or tin in samples containing different organic species by flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) and speciation analysis by coupled high-performance liquid chromatography (HPLC) with HGAAS detection. For organoarsenicals, the reaction with alkaline peroxodisulfate in a 10-15-m knotted reactor for >1.5 min insures >90% transformation of inorganic As(III) and six organoarsenic species to arsenate: monomethylarsonate, dimethylarsinate, arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium. For organotins, the UV photooxidation with acidic peroxodisulfate at 95-100°C provides recoveries of >80% for the inorganic tin, dimethyltin, trimethyltin, triethyltin, tripropyltin, triphenyltin, monobutyltin, dibutyltin and tributyltin but only approximately 15% for tetrabutyltin. The best characteristic masses in integrated absorbance ( Aint) and peak-height ( Ap) measurements, respectively, are 30 pg and 480 pg for arsenic(V) and 22 pg and 410 pg for tin(IV), employing 100-μl injections. The RSDs are 5.5% and 8.5% at 5 ng As(V) levels and 4.3% and 6.4% at 10 ng Sn(IV) levels in Aint and Ap modes, respectively. The limits of detection (LOD, 3σ) for As are 7 μg l -1 and 4 μg l -1 in FI-UV-HGAAS and HPLC-UV-HGAAS, respectively. The LODs for i-Sn(IV) are 2 μg l -1 in FI-UV-HGAAS, with both Aint and Ap measurements. The sample throughput rates are 20 and 12 samples per hour with 10-m and 15-m knotted reactors (i.d. 0.5 mm), respectively. Urine certified reference materials containing 0.052-0.48 μg ml -1 As have been analysed for their total arsenic content.

  20. Measurement of elemental speciation by liquid chromatography -- inductively coupled plasma mass spectrometry (LC-ICP-MS) with the direct injection nebulizer (DIN)

    SciTech Connect

    Shum, Sam

    1993-05-01

    This thesis is divided into 4 parts: elemental speciation, speciation of mercury and lead compounds by microbore column LC-ICP-MS with direct injection nebulization, spatially resolved measurements of size and velocity distributions of aerosol droplets from a direct injection nebulizer, and elemental speciation by anion exchange and size exclusion chromatography with detection by ICP-MS with direct injection nebulization.

  1. Determination and temperature effects of lidocaine (lignocaine) hydrochloride, epinephrine, methylparaben, 2,6-dimethylaniline, and p-hydroxybenzoic acid in USP lidocaine injection by ion-pair reversed-phase high pressure liquid chromatography

    SciTech Connect

    Smith, D.J.

    1981-05-01

    USP Lidocaine injection was assayed using ion-pair high pressure liquid chromatography with an octylsilane (RP-8) reversed-phase column packing and a mobile phase consisting of D-10-camphorsulfonic acid/methanol/acetic acid/water. The effect of temperature was investigated to determine the optimum temperature for separating the drug components and their degradation products. Lidocaine (lignocaine) hydrochloride, epinephrine, methylparaben, and p-hydroxybenzoic acid were separated at 50 degrees C. 2,6-Dimethylaniline was separated from lidocaine at 15 degrees C. An aliquot of the sample was injected directly into the liquid chromatograph, and after separation the compounds were quantitated by their spectrophotometric response at 254 nm (lidocaine) or 280 nm (lidocaine plus epinephrine).

  2. Caractérisation de l'augmentation des transferts thermiques dans une couche de liquide diélectrique soumise à une injection unipolaire de charges électriques

    NASA Astrophysics Data System (ADS)

    Traoré, Philippe; Koulova-Nenova, D.; Romat, H.; Perez, A.

    2009-03-01

    The electro-thermo-convective flow in a horizontal dielectric liquid layer placed between two electrodes and subjected to an injection of electric charges from one of the electrodes and at the same time to a thermal gradient is studied numerically. We consider the case of a strong charge injection in order to only take into account the Coulomb force disregarding the dielectric forces, from above and below the layer. The effect of the action of both electric and thermal fields on the dielectric liquid layer is analyzed and the behavior of the flow when these fields compete or cooperate is studied. It is demonstrated that the electrically induced convection enhances the heat transfer. To cite this article: Ph. Traoré et al., C. R. Mecanique 337 (2009).

  3. Determination and temperature effects of lidocaine (lignocaine) hydrochloride, epinephrine, methylparaben, 2,6-dimethylaniline, and p-hydroxybenzoic acid in USP lidocaine injection by ion-pair reversed-phase high pressure liquid chromatography.

    PubMed

    Smith, D J

    1981-05-01

    USP Lidocaine injection was assayed using ion-pair high pressure liquid chromatography with an octylsilane (RP-8) reversed-phase column packing and a mobile phase consisting of D-10-camphorsulfonic acid/methanol/acetic acid/water. The effect of temperature was investigated to determine the optimum temperature for separating the drug components and their degradation products. Lidocaine (lignocaine) hydrochloride, epinephrine, methylparaben, and p-hydroxybenzoic acid were separated at 50 degrees C. 2,6-Dimethylaniline was separated from lidocaine at 15 degrees C. An aliquot of the sample was injected directly into the liquid chromatograph, and after separation the compounds were quantitated by their spectrophotometric response at 254 nm (lidocaine) or 280 nm (lidocaine plus epinephrine).

  4. Analysis of thiabendazole, 4-tert-octylphenol and chlorpyrifos in waste and sewage water by direct injection – micellar liquid chromatography.

    PubMed

    Romero-Cano, Ricard; Kassuha, Diego; Peris-Vicente, Juan; Roca-Genovés, Pasqual; Carda-Broch, Samuel; Esteve-Romero, Josep

    2015-03-07

    A micellar liquid chromatographic method has been developed for the simultaneous quantification of the pesticides thiabendazole and chlorpyrifos, as well as an alkylphenol, which is included in pesticide formulations, i.e., 4-tert-octylphenol, in water. A sample was filtered and directly injected, avoiding large extraction steps using toxic solvents, thus expediting the experimental procedure. The contaminants were eluted without interferences in <17 min, using a mobile phase of 0.15 M sodium dodecyl sulfate – 6% 1-pentanol buffered at pH 3, running through a C18 column at 1 mL min(-1) under the isocratic mode. This optimal mobile phase was selected using a statistical approach, which considers the retention factor, efficiency and peak shape of the analytes measured in only a few mobile phases. The detection was carried out by measuring absorbance at 220 nm. The method was successfully validated in terms of specificity, calibration range (0.5-10 mg L(-1)), linearity (r(2) > 0.994), limit of detection and quantification (0.2-0.3; and 0.5-0.8 mg L(-1), respectively), intra- and interday accuracy (95.2-102.9%), precision (<8.3%), and ruggedness (<9.3%). The stability in storage conditions (at least 14 days) was studied. The method was safe, inexpensive, produced little pollutant and has a short analysis time, thus it is useful for the routine analysis of samples. Finally, the method was applied to analyse wastewater from the fruit-processing industry, wastewater treatment plants, and in sewage water belonging to the Castelló area (Spain). The results were similar to those obtained by an already reliable method.

  5. Determination of salivary cotinine through solid phase extraction using a bead-injection lab-on-valve approach hyphenated to hydrophilic interaction liquid chromatography.

    PubMed

    Ramdzan, Adlin N; Barreiros, Luísa; Almeida, M Inês G S; Kolev, Spas D; Segundo, Marcela A

    2016-01-15

    Cotinine, the first metabolite of nicotine, is often used as a biomarker in the monitoring of environmental tobacco smoke (ETS) exposure due to its long half-life. This paper reports on the development of an at-line automatic micro-solid phase extraction (μSPE) method for the determination of salivary cotinine followed by its analysis via hydrophilic interaction liquid chromatography (HILIC). The SPE methodology is based on the bead injection (BI) concept in a mesofluidic lab-on-valve (LOV) flow system to automatically perform all SPE steps. Three commercially available reversed-phase sorbents were tested, namely, Oasis HLB, Lichrolut EN and Focus, and the spherically shaped sorbents (i.e., Oasis HLB and Focus) provided better packing within the SPE column and hence higher column efficiency. An HILIC column was chosen based on its potential for achieving higher sensitivity and better retention of polar compounds such as cotinine. The method uses an isocratic program with acetonitrile:100mM ammonium acetate buffer, pH 5.8 in 95:5 v/v ratio as the mobile phase at a flow rate of 1.0 mL min(-1). Using this approach, the linear calibration range was from 10 to 1000 ng which corresponded to 5-500 μg L(-1). The corresponding μSPE-BI-LOV system was proven to be reliable in the handing and analysis of viscous biological samples such as saliva, achieving a sampling rate of 6h(-1) and a limit of detection and quantification of 1.5 and 3μgL(-1), respectively.

  6. The determination of acrylamide in environmental and drinking waters by large-volume injection - hydrophilic-interaction liquid chromatography and tandem mass spectrometry.

    PubMed

    Backe, Will J; Yingling, Virginia; Johnson, Todd

    2014-03-21

    A simple and sensitive analytical method was developed to quantify levels of acrylamide in environmental and drinking waters. The analytical method consisted of solvent exchanging acrylamide from 2mL of water into 2mL of dichloromethane using acetonitrile as an intermediate. The sample was then directly analyzed by large-volume (750μL) injection - hydrophilic-interaction liquid chromatography and tandem mass spectrometry. The method detection limit and reporting level were 2.4ng/L and 17ng/L of acrylamide, respectively. The recovery of acrylamide during solvent exchange was 95±2.8% and the matrix effects were 12±2.2% in river water. The use of atmospheric-pressure chemical ionization reduced matrix effects; however, it also reduced method sensitivity by a factor of 2.2 compared to electrospray ionization. Matrix effects were compensated for by the use of an isotopically-labeled internal standard and the method accuracy was 89±3.0% at 25ng/L of acrylamide and 102±2.6% at 250ng/L of acrylamide. The precision of the method was less than 6% relative standard deviation at both 25ng/L and 250ng/L of acrylamide. Samples from a sand-and-gravel mine and a drinking-water treatment plant were acquired to demonstrate the method. The concentrations of acrylamide at the sand-and-gravel mine were up to 280ng/L. In the drinking-water treatment plant, the concentration of acrylamide was approximately double in the finished drinking water when compared to other stages in the drinking-water treatment process. Disinfection or fluoridation may result in higher concentrations of acrylamide in finished drinking water; however, further research in this area is necessary.

  7. High-throughput method for the analysis of ethylenethiourea with direct injection of hydrolysed urine using online on-column extraction liquid chromatography and triple quadrupole mass spectrometry.

    PubMed

    Ekman, Eva; Maxe, Margaretha; Littorin, Margareta; Jönsson, Bo A G; Lindh, Christian H

    2013-09-01

    Ethylenethiourea (ETU) is of major toxicological concern, since in experimental animal studies, ETU has shown a large spectrum of adverse effects. High occupational exposure can be found among agricultural workers or during manufacturing of ethylenbisdithiocarbamates (EBDC). For the general public, sources of environmental exposure may be residues of ETU in commercial products, food and beverages. For the determination of ETU in human urine we present a high-throughput online on-column extraction liquid chromatography triple quadrupole mass spectrometry method using direct injection of hydrolysed urine samples. This method is simple, user- and environmentally friendly and all sample preparation is performed in 96-well plates. A labelled ETU internal standard was used for quantification. The method showed a good sensitivity with a limit of quantification (LOQ) of 0.5ng ETU/mL urine and the calibration curve was linear in the range 0.25-200ng ETU/mL urine. The within-run, between-run and between-batch precision was between 6% and 13%. Alkaline hydrolysis considerably increased the levels of ETU indicating a potential conjugate. The method was applied in an experimental dermal exposure study in humans, with sample concentrations ranging from 0.4 to 5.0ng ETU/mL urine. The excretion in urine was 10% of the applied dose. The elimination profile seemed to differ between the two individuals. The results show an estimated half-life of ETU between 34 and 72h. Although the experiment is limited to two individuals, the data provide valuable and new information regarding the toxicokinetics of ETU after dermal exposure.

  8. Simplifying and expanding analytical capabilities for various classes of doping agents by means of direct urine injection high performance liquid chromatography high resolution/high accuracy mass spectrometry.

    PubMed

    Görgens, Christian; Guddat, Sven; Thomas, Andreas; Wachsmuth, Philipp; Orlovius, Anne-Katrin; Sigmund, Gerd; Thevis, Mario; Schänzer, Wilhelm

    2016-11-30

    So far, in sports drug testing compounds of different classes are processed and measured using different screening procedures. The constantly increasing number of samples in doping analysis, as well as the large number of substances with doping related, pharmacological effects require the development of even more powerful assays than those already employed in sports drug testing, indispensably with reduced sample preparation procedures. The analysis of native urine samples after direct injection provides a promising analytical approach, which thereby possesses a broad applicability to many different compounds and their metabolites, without a time-consuming sample preparation. In this study, a novel multi-target approach based on liquid chromatography and high resolution/high accuracy mass spectrometry is presented to screen for more than 200 analytes of various classes of doping agents far below the required detection limits in sports drug testing. Here, classic groups of drugs as diuretics, stimulants, β2-agonists, narcotics and anabolic androgenic steroids as well as various newer target compounds like hypoxia-inducible factor (HIF) stabilizers, selective androgen receptor modulators (SARMs), selective estrogen receptor modulators (SERMs), plasma volume expanders and other doping related compounds, listed in the 2016 WADA prohibited list were implemented. As a main achievement, growth hormone releasing peptides could be implemented, which chemically belong to the group of small peptides (<2kDa) and are commonly determined by laborious and time-consuming stand-alone assays. The assay was fully validated for qualitative purposes considering the parameters specificity, robustness (rRT: <2%), intra- (CV: 1.7-18.4 %) and inter-day precision (CV: 2.3-18.3%) at three concentration levels, linearity (R(2)>0.99), limit of detection (0.1-25ng/mL; 3'OH-stanozolol glucuronide: 50pg/mL; dextran/HES: 10μg/mL) and matrix effects.

  9. Cabazitaxel Injection

    MedlinePlus

    ... injection is used along with prednisone to treat prostate cancer (cancer of a male reproductive organ) that has ... cabazitaxel injection is usually used in men with prostate cancer. If used by pregnant women, cabazitaxel injection can ...

  10. Fondaparinux Injection

    MedlinePlus

    ... fondaparinux injection.Talk to your doctor about the risk of using fondaparinux injection. ... Fondaparinux injection is used to prevent deep vein thrombosis (DVT; a blood ... Xa inhibitors. It works by decreasing the clotting ability of the blood.

  11. Dexamethasone Injection

    MedlinePlus

    Dexamethasone injection is used to treat severe allergic reactions. It is used in the management of certain types of ... gastrointestinal disease, and certain types of arthritis. Dexamethasone injection is also used for diagnostic testing. Dexamethasone injection ...

  12. Romidepsin Injection

    MedlinePlus

    Romidepsin injection is used to treat cutaneous T-cell lymphoma (CTCL; a group of cancers of the immune system ... one other medication given by mouth or by injection. Romidepsin injection is in a class of medications ...

  13. Ondansetron Injection

    MedlinePlus

    Zofran® Injection ... Ondansetron injection is used to prevent nausea and vomiting caused by cancer chemotherapy and surgery. Ondansetron is in a ... medications: or any of the ingredients in ondansetron injection. Ask your pharmacist for a list of the ...

  14. A novel needleless liquid jet injection methodology for improving direct cardiac gene delivery: An optimization of parameters, AAV mediated therapy and investigation of host responses in ischemic heart failure

    NASA Astrophysics Data System (ADS)

    Fargnoli, Anthony Samuel

    Heart disease remains the leading cause of mortality and morbidity worldwide, with 22 million new patients diagnosed annually. Essentially, all present therapies have significant cost burden to the healthcare system, yet fail to increase survival rates. One key employed strategy is the genetic reprogramming of cells to increase contractility via gene therapy, which has advanced to Phase IIb Clinical Trials for advanced heart failure patients. It has been argued that the most significant barrier preventing FDA approval are resolving problems with safe, efficient myocardial delivery, whereby direct injection in the infarct and remote tissue areas is not clinically feasible. Here, we aim to: (1) Improve direct cardiac gene delivery through the development of a novel liquid jet device approach (2) Compare the new method against traditional IM injection with two different vector constructions and evaluate outcome (3) Evaluate the host response resulting from both modes of direct cardiac injection, then advance a drug/gene combination with controlled release nanoparticle formulations.

  15. Monitoring and Controlling of Strain During MOCVD of AlGaN for UV Optoelectronics

    SciTech Connect

    Han, J.; Crawford, M.H.; Shul, R.J.; Hearne, S.J.; Chason, E.; Figiel, J.J.; Banas, M.

    1999-01-14

    The grown-in tensile strain, due to a lattice mismatch between AlGaN and GaN, is responsible for the observed cracking that seriously limits the feasibility of nitride-based ultraviolet (UV) emitters. We report in-situ monitoring of strain/stress during MOCVD of AlGaN based on a wafer-curvature measurement technique. The strain/stress measurement confirms the presence of tensile strain during growth of AlGaN pseudomorphically on a thick GaN layer. Further growth leads to the onset of stress relief through crack generation. We find that the growth of AlGaN directly on low-temperature (LT) GaN or AlN buffer layers results in a reduced and possibly controllable strain.

  16. Three-dimensional modelling of horizontal chemical vapor deposition. I - MOCVD at atmospheric pressure

    NASA Technical Reports Server (NTRS)

    Ouazzani, Jalil; Rosenberger, Franz

    1990-01-01

    A systematic numerical study of the MOCVD of GaAs from trimethylgallium and arsine in hydrogen or nitrogen carrier gas at atmospheric pressure is reported. Three-dimensional effects are explored for CVD reactors with large and small cross-sectional aspect ratios, and the effects on growth rate uniformity of tilting the susceptor are investigated for various input flow rates. It is found that, for light carrier gases, thermal diffusion must be included in the model. Buoyancy-driven three-dimensional flow effects can greatly influence the growth rate distribution through the reactor. The importance of the proper design of the lateral thermal boundary conditions for obtaining layers of uniform thickness is emphasized.

  17. Growth of AlN nanostructure on GaN using MOCVD

    SciTech Connect

    Loganathan, R.; Ramesh, R.; Jayasakthi, M.; Prabakaran, K.; Kuppulingam, B.; Sankaranarayanan, M.; Balaji, M.; Arivazhagan, P.; Singh, Subra; Baskar, K.

    2015-06-24

    Aluminum nitride (AlN) nanowalls have been epitaxially grown on dislocation assisted GaN/Al{sub 2}O{sub 3} template by metal organic chemical vapor deposition (MOCVD) without any help of metal catalysts. A large number of nanowalls with thicknesses of 1.5-2.0 µm and height 400 nm have been deposited. The AlN nanowalls were found to have a preferred c-axis oriented with a hexagonal crystal structure. The AlN nanowalls and GaN/Al{sub 2}O{sub 3} template have been characterize at room temperature photoluminescence (PL) and high resolution X-ray diffraction (HRXRD)

  18. MOCVD growth of CdO very thin films: Problems and ways of solution

    NASA Astrophysics Data System (ADS)

    Huerta-Barberà, Adelaida; Guia, Lluís Manel; Klymov, Oleksii; Marín-Borrás, Vicente; Martínez-Tomás, Carmen; Tamayo-Arriola, Julen; Kurtz, Alejandro; Montes Bajo, Miguel; Muñoz, Elias; Hierro, Adrian; Muñoz-Sanjosé, Vicente

    2016-11-01

    In this paper the growth of CdO by the MOCVD technique at atmospheric pressure has been studied in order to achieve very thin films of this material on r-sapphire substrates. The growth evolution of these films was discussed and the existence of a threshold thickness, below which island-shaped structures appear, was demonstrated. Some alternatives to reduce this threshold thickness have been proposed in the frame of the analysis of the crystal growth process. The morphology and structural properties of the films were analyzed by means of SEM and HRXRD. High-quality flat CdO samples were achieved with thicknesses up to 20 nm, which is five times thinner than the values previously reported in the literature.

  19. MOCVD Growth of High-Quality and Density-Tunable GaAs Nanowires on ITO Catalyzed by Au Nanoparticles Deposited by Centrifugation.

    PubMed

    Wu, Dan; Tang, Xiaohong; Yoon, Ho Sup; Wang, Kai; Olivier, Aurelien; Li, Xianqiang

    2015-12-01

    High-quality and density-tunable GaAs nanowires (NWs) are directly grown on indium tin oxide (ITO) using Au nanoparticles (NPs) as catalysts by metal organic chemical vapor deposition (MOCVD). Au catalysts were deposited on ITO glass substrate using a centrifugal method. Compared with the droplet-only method, high-area density Au NPs were uniformly distributed on ITO. Tunable area density was realized through variation of the centrifugation time, and the highest area densities were obtained as high as 490 and 120 NP/μm(2) for 10- and 20-nm diameters of Au NPs, respectively. Based on the vapor-liquid-solid growth mechanism, the growth rates of GaAs NWs at 430 °C were 18.2 and 21.5 nm/s for the highest area density obtained of 10- and 20-nm Au NP-catalyzed NWs. The growth rate of the GaAs NWs was reduced with the increase of the NW density due to the competition of precursor materials. High crystal quality of the NWs was also obtained with no observable planar defects. 10-nm Au NP-induced NWs exhibit wurtzite structure whereas zinc-blende is observed for 20-nm NW samples. Controllable density and high crystal quality of the GaAs NWs on ITO demonstrate their potential application in hybrid a solar cell.

  20. The preparation of ZnS:Mn electroluminescent layers by MOCVD using new manganese sources

    NASA Astrophysics Data System (ADS)

    Migita, M.; Kanehisa, O.; Shiiki, M.; Yamamoto, H.

    1988-12-01

    In the preparation of ZnS:Mn polycrystalline films by MOCVD, CPM [(C 5H 5) 2Mn: di-π-cyclopentadienyl manganese] and BCPM [(CH 3C 5H 4) 2Mn: bismethylcyclopentadienyl manganese] are employed as new doping sources, and are compared with previously reported TCM [(CH 3C 5H 4)Mn(CO) 3: tricarbonyl methylcyclopentadienyl manganese]. In contrast to TCM, which is only partially decomposed even at 400 ˜ 500°C, CPM and BCPM are completely decomposed around the optimum growth temperature of ZnS, i.e. 280-350°C. When thermally decomposed, TCM produces a by-product containing Mn and carbonyl, which does not contribute to the luminescence, but CPM and BCPM do not. By these advantages, the double-insulator type electroluminescent (EL) devices prepared with CPM or BCPM show higher luminance than those prepared with TCM. A 500 nm thick ZnS:Mn layer by CPM gives the maximum efficiency ( ηmax) of 4.8 lm/W and a saturated luminance ( Lsat) of 4300 cd/m 2 at 1 kHz sine wave excitation. By BCPM, Lsat of 3150 cd/m 2 was obtained. Meanwhile, the devices prepared with TCM in this investigation show Lsat to be less than 1000 cd/m 2 and a low efficiency of less than 1 lm/W. By the combination with red filters, ZnS:Mn by MOCVD with CPM or BCPM can also provide efficient red EL. When a glass filter (the cut-off wavelength is 590 nm) is used, the EL device prepared with CPM gives Lsat=1420 cd/m 2 and ηmax=1.6 lm/W (the color coordinates, x=0.626 and y=0.373) at 1 kHz sine wave excitation.

  1. Hardware Modifications to the US Army Research Laboratory’s Metalorganic Chemical Vapor Deposition (MOCVD) System for Optimization of Complex Oxide Thin Film Fabrication

    DTIC Science & Technology

    2015-04-01

    melanie.w.cole.civ@mail.mil. 14. ABSTRACT An introduction to various metalorganic chemical vapor deposition (MOCVD) reactor designs and precursor...flow and chemical reactions occurring in the reactor chamber at the substrate surface. A substantial amount of research has been dedicated to...coupled showerhead MOCVD reactor . Microelectronics Journal. 2009;40:280–282. 8. Wessels BW. Metal-organic chemical -vapor-deposition of ferroelectric

  2. Leuprolide Injection

    MedlinePlus

    Leuprolide injection comes as a long-acting suspension (Lupron) that is injected intramuscularly (into a muscle) by a doctor or nurse in a medical ... Depot-4 month, Lupron Depot-6 Month). Leuprolide injection also comes as a long-acting suspension (Eligard) that is injected subcutaneously (just under ...

  3. Development of a sequential injection-liquid microextraction procedure with GC-FID for analysis of short-chain fatty acids in palm oil mill effluent.

    PubMed

    Pruksatrakul, Thapanee; Phoopraintra, Pattamaporn; Wilairat, Prapin; Chaiyen, Pimchai; Chantiwas, Rattikan

    2017-04-01

    Short-chain fatty acids, such as acetic, propionic, butyric, iso-valeric and valeric acids, play an important role in methanogenesis activity for biogas production processes. Thus, simple and rapid procedures for monitoring the levels of short-chain fatty acids are requisite for sustaining biogas production. This work presents the development of a sequential injection-liquid microextraction (SI-LME) procedure with GC-FID analysis for determination of short-chain fatty acids. GC-FID was employed for detection of the short-chain fatty acids. Calibration curves were linear with good coefficients of determination (r(2)>0.999), using methacrylic acid as the internal standard. Limits of quantification (LOQ) were in the range of 0.03-0.19mM. The SI-LME procedure employed tert-butyl methyl ether (TBME) as the extracting solvent. Various SI-LME conditions were investigated and optimized to obtain the highest recovery of extraction. With these optimized conditions, an extraction recovery of the five key short-chain fatty acids of 67-90% was obtained, with less than 2% RSD (n=3). The final SI-LME procedure employed two fluidic zones of TBME with a single aqueous fluidic zone of sample sandwiched between the TBME zones, with 5 cycles of flow reversal at a flow rate of 5µL/s for the extraction process. Intra- and inter-day precision values were 0.5-4.0% RSD and 3.3-4.8% RSD, respectively. Accuracy based on percentage of sample recovery were in the range of 69-96, 102-107, and 82-101% (n=4) for acetic, propionic and butyric acids, respectively. The proposed method was applied for the measurement of short-chain fatty acids in palm oil mill effluents used in biogas production in a factory performing palm oil extraction process. The SI-LME method provides improved extraction performance with high precision, and is both simple and rapid with its economical extraction technique. The SI-LME procedure with GC-FID has strong potential for use as a quality control process for monitoring

  4. Determination of human-use pharmaceuticals in filtered water by direct aqueous injection: high-performance liquid chromatography/tandem mass spectrometry

    USGS Publications Warehouse

    Furlong, Edward T.; Noriega, Mary C.; Kanagy, Christopher J.; Kanagy, Leslie K.; Coffey, Laura J.; Burkhardt, Mark R.

    2014-01-01

    This report describes a method for the determination of 110 human-use pharmaceuticals using a 100-microliter aliquot of a filtered water sample directly injected into a high-performance liquid chromatograph coupled to a triple-quadrupole tandem mass spectrometer using an electrospray ionization source operated in the positive ion mode. The pharmaceuticals were separated by using a reversed-phase gradient of formic acid/ammonium formate-modified water and methanol. Multiple reaction monitoring of two fragmentations of the protonated molecular ion of each pharmaceutical to two unique product ions was used to identify each pharmaceutical qualitatively. The primary multiple reaction monitoring precursor-product ion transition was quantified for each pharmaceutical relative to the primary multiple reaction monitoring precursor-product transition of one of 19 isotope-dilution standard pharmaceuticals or the pesticide atrazine, using an exact stable isotope analogue where possible. Each isotope-dilution standard was selected, when possible, for its chemical similarity to the unlabeled pharmaceutical of interest, and added to the sample after filtration but prior to analysis. Method performance for each pharmaceutical was determined for reagent water, groundwater, treated drinking water, surface water, treated wastewater effluent, and wastewater influent sample matrixes that this method will likely be applied to. Each matrix was evaluated in order of increasing complexity to demonstrate (1) the sensitivity of the method in different water matrixes and (2) the effect of sample matrix, particularly matrix enhancement or suppression of the precursor ion signal, on the quantitative determination of pharmaceutical concentrations. Recovery of water samples spiked (fortified) with the suite of pharmaceuticals determined by this method typically was greater than 90 percent in reagent water, groundwater, drinking water, and surface water. Correction for ambient environmental

  5. Study of high {Tc} superconducting thin films grown by MOCVD. Final report, July 1, 1986--April 30, 1990

    SciTech Connect

    Erbil, A.

    1990-12-31

    Work is described briefly, which was carried out on development of techniques to grow metal-semiconductor superlattices (artificially layered materials) and on the copper oxide based susperconductors (naturally layered materials). The current growth technique utilized is metalorganic chemical vapor deposition (MOCVD). CdTe, PbTe, La, LaTe, and Bi{sub 2}Te{sub 3} were deposited, mostly on GaAs. Several YBa{sub 2}Cu{sub 3}O{sub 7} compounds were obtained with possible superconductivity at temperatures up to 550 K (1 part in 10{sup 4}). YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} and Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub y} thin films were deposited by MOCVD on common substrates such as glass.

  6. Injection, atomization, ignition and combustion of liquid fuels in high-speed air streams. Annual scientific report 1 December 81-31 December 82

    SciTech Connect

    Schetz, J.A.

    1983-01-01

    A simulation approach to studying hot flow subsonic cross-stream fuel injection problems in a less complex and costly cold flow facility was developed. A typical ramjet combustion chamber fuel injection problem was posed where ambient temperature fuel (Kerosene) is injected into a hot airstream. This case was transformed through two new similarity parameters involving injection and freestream properties to a simulated case where a chilled injectant is injected into an ambient temperature airstream. Experiments for the simulated case using chilled Freon-12 injected into the Va. Tech 23 x 23 cm. blow-down wind tunnel at a freestream Mach number of 0.44 were run. The freestream stagnation pressure and temperature were held at 2.5 atm. and 300 degrees K respectively. Results showed a clear picture of the mechanisms of jet decomposition in the presence of rapid vaporization. Immediately after injection a vapor cloud was formed in the jet plume, which dissipated downstream leaving droplets on the order of 8 to 10 microns in diameter for the conditions examined. This represents a substantial reduction compared to baseline tests run at the same conditions with water which had little vaporization. The desirability of using slurry fuels for aerospace application has long been recognized, but the problems of slurry combustion have delayed their use. The present work is an experimental and numerical investigation into the break-up and droplet formation of laminar slurry jets issuing into quiescent air.

  7. OPTIMIZED DETERMINATION OF TRACE JET FUEL VOLATILE ORGANIC COMPOUNDS IN HUMAN BLOOD USING IN-FIELD LIQUID-LIQUID EXTRACTION WITH SUBSEQUENT LABORATORY GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS AND ON-COLUMN LARGE VOLUME INJECTION

    EPA Science Inventory

    A practical and sensitive method to assess volatile organic compounds (VOCs) from JP-8 jet fuel in human whole blood was developed by modifying previously established liquid-liquid extraction procedures, optimizing extraction times, solvent volume, specific sample processing te...

  8. Ultra-trace level determination of diquat and paraquat residues in surface and drinking water using ion-pair liquid chromatography with tandem mass spectrometry: a comparison of direct injection and solid-phase extraction methods.

    PubMed

    Oh, Jin-Aa; Lee, Jun-Bae; Lee, Soo-Hyung; Shin, Ho-Sang

    2014-10-01

    Direct injection and solid-phase extraction methods for the determination of diquat and paraquat in surface and drinking water were developed using liquid chromatography with tandem mass spectrometry. The signal intensities of analytes based on six ion-pairing reagents were compared with each other, and 12.5 mM nonafluoropentanoic acid was selected as the best suited amongst them. A clean-up method was developed using Oasis hydrophilic-lipophilic balance; this was compared to the direct injection method, with respect to limits of detection, interference, precision, and accuracy. Limits of quantification of diquat and paraquat were 0.03 and 0.01 μg/L using the direct injection method, and 0.002 and 0.001 μg/L using the hydrophilic-lipophilic balance method. When the hydrophilic-lipophilic balance method was used to analyze target compounds in 114 surface water and 30 drinking water samples, paraquat and diquat were detected within a concentration range of 0.001-0.12 and 0.002-0.038 μg/L in surface water, respectively. When the direct injection method was used to analyze target compounds in the same samples, the detected concentrations of paraquat and diquat were within 25% in samples being >0.015 μg/L using the hydrophilic-lipophilic balance method. The liquid chromatography with tandem mass spectrometry method using direct injection can thus be used for routine monitoring of paraquat and diquat in surface and drinking water.

  9. Porous media heat transfer for injection molding

    DOEpatents

    Beer, Neil Reginald

    2016-05-31

    The cooling of injection molded plastic is targeted. Coolant flows into a porous medium disposed within an injection molding component via a porous medium inlet. The porous medium is thermally coupled to a mold cavity configured to receive injected liquid plastic. The porous medium beneficially allows for an increased rate of heat transfer from the injected liquid plastic to the coolant and provides additional structural support over a hollow cooling well. When the temperature of the injected liquid plastic falls below a solidifying temperature threshold, the molded component is ejected and collected.

  10. Sequential injection-bead injection-lab-on-valve coupled to high-performance liquid chromatography for online renewable micro-solid-phase extraction of carbamate residues in food and environmental samples.

    PubMed

    Vichapong, Jitlada; Burakham, Rodjana; Srijaranai, Supalax; Grudpan, Kate

    2011-07-01

    A sequential injection-bead injection-lab-on-valve system was hyphenated to HPLC for online renewable micro-solid-phase extraction of carbamate insecticides. The carbamates studied were isoprocarb, methomyl, carbaryl, carbofuran, methiocarb, promecarb, and propoxur. LiChroprep(®) RP-18 beads (25-40 μm) were employed as renewable sorbent packing in a microcolumn situated inside the LOV platform mounted above the multiposition valve of the sequential injection system. The analytes sorbed by the microcolumn were eluted using 80% acetonitrile in 0.1% acetic acid before online introduction to the HPLC system. Separation was performed on an Atlantis C-18 column (4.6 × 150 mm, 5 μm) utilizing gradient elution with a flow rate of 1.0 mL/min and a detection wavelength at 270 nm. The sequential injection system offers the means of performing automated handling of sample preconcentration and matrix removal. The enrichment factors ranged between 20 and 125, leading to limits of detection (LODs) in the range of 1-20 μg/L. Good reproducibility was obtained with relative standard deviations of <0.7 and 5.4% for retention time and peak area, respectively. The developed method has been successfully applied to the determination of carbamate residues in fruit, vegetable, and water samples.

  11. Golimumab Injection

    MedlinePlus

    ... body and causes pain, swelling, and damage) including: rheumatoid arthritis (condition in which the body attacks its own ... doctor.If golimumab injection is used to treat rheumatoid arthritis, it may also be injected intravenously (into a ...

  12. Adalimumab Injection

    MedlinePlus

    ... causes pain, swelling, and damage) including the following: rheumatoid arthritis (a condition in which the body attacks its ... If you are using adalimumab injection to treat rheumatoid arthritis, your doctor may tell you to inject the ...

  13. Aripiprazole Injection

    MedlinePlus

    ... aripiprazole injection and aripiprazole extended-release injection developed gambling problems or other intense urges or behaviors that ... even if you do not realize that your gambling or any other intense urges or unusual behaviors ...

  14. Degarelix Injection

    MedlinePlus

    Degarelix injection is used to treat advanced prostate cancer (cancer that begins in the prostate [a male reproductive gland]). Degarelix injection is in a class of medications called gonadotropin-releasing hormone (GnRH) ...

  15. Cyclosporine Injection

    MedlinePlus

    ... injection is used with other medications to prevent transplant rejection (attack of the transplanted organ by the ... people who have received kidney, liver, and heart transplants. Cyclosporine injection should only be used to treat ...

  16. Colistimethate Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria. Colistimethate injection is in a class of medications called antibiotics. It works by killing bacteria.Antibiotics such as colistimethate injection will not work ...

  17. Chloramphenicol Injection

    MedlinePlus

    ... treat certain types of serious infections caused by bacteria when other antibiotics cannot be used. Chloramphenicol injection ... antibiotics. It works by stopping the growth of bacteria..Antibiotics such as chloramphenicol injection will not work ...

  18. Estrogen Injection

    MedlinePlus

    ... forms of estrogen injection are used to treat hot flushes (hot flashes; sudden strong feelings of heat and sweating) ... If you are using estrogen injection to treat hot flushes, your symptoms should improve within 1 to ...

  19. Medroxyprogesterone Injection

    MedlinePlus

    ... Medroxyprogesterone injection is a very effective method of birth control but does not prevent the spread of human ... you have been using a different method of birth control and are switching to medroxyprogesterone injection, your doctor ...

  20. Etanercept Injection

    MedlinePlus

    ... areas causing pain and joint damage), chronic plaque psoriasis (a skin disease in which red, scaly patches ... etanercept injection is used to treat chronic plaque psoriasis, it may be injected twice a week during ...

  1. Levoleucovorin Injection

    MedlinePlus

    Levoleucovorin injection is used to prevent harmful effects of methotrexate (Rheumatrex, Trexall) when methotrexate is used to to treat certain types of cancer. Levoleucovorin injection is also used to treat people ...

  2. Leucovorin Injection

    MedlinePlus

    Leucovorin injection is used to prevent harmful effects of methotrexate (Rheumatrex, Trexall; cancer chemotherapy medication) when methotrexate is used to to treat certain types of cancer. Leucovorin injection is used to ...

  3. Teniposide Injection

    MedlinePlus

    ... in men. You should not become pregnant or breast-feed while you are receiving teniposide injection. If you or your partner become pregnant while receiving teniposide injection, call your doctor. Teniposide may harm the fetus.

  4. Ipilimumab Injection

    MedlinePlus

    ... are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving ipilimumab injection, call your doctor. Ipilimumab injection may cause your baby to be born too early or to die before birth.

  5. Pralatrexate Injection

    MedlinePlus

    Pralatrexate injection is used to treat peripheral T-cell lymphoma (PTCL; a form of cancer that begins in a ... come back after treatment with other medications. Pralatrexate injection has not been shown to help people who ...

  6. Cyanocobalamin Injection

    MedlinePlus

    Cyanocobalamin injection is used to treat and prevent a lack of vitamin B12 that may be caused by any ... organs) and permanent damage to the nerves. Cyanocobalamin injection also may be given as a test to ...

  7. Paclitaxel Injection

    MedlinePlus

    Paclitaxel injection manufactured with human albumin is used to treat breast cancer that has not improved or that has come back after treatment with other medications. Paclitaxel injection manufactured with polyoxyethylated castor oil is used to ...

  8. Diphenhydramine Injection

    MedlinePlus

    Diphenhydramine injection is used to treat allergic reactions, especially for people who are unable to take diphenhydramine by mouth. ... is used also to treat motion sickness. Diphenhydramine injection is also used alone or along with other ...

  9. Peramivir Injection

    MedlinePlus

    Peramivir injection is used to treat some types of influenza infection ('flu') in people who have had symptoms of ... flu for no longer than 2 days. Peramivir injection is in a class of medications called neuraminidase ...

  10. Cefotetan Injection

    MedlinePlus

    Cefotetan injection is used to treat infections of the lungs, skin, bones, joints, stomach area, blood, female reproductive organs, and urinary tract. Cefotetan injection is also used before surgery to prevent infections. ...

  11. Mipomersen Injection

    MedlinePlus

    Mipomersen injection is used to decrease levels of cholesterol and other fatty substances in the blood in people who ... that removes LDL from the blood), but mipomersen injection should not be used along with this treatment. ...

  12. Romiplostim Injection

    MedlinePlus

    Romiplostim injection is used to increase the number of platelets (cells that help the blood to clot) in order ... low number of platelets in the blood). Romiplostim injection should only be used in people who cannot ...

  13. Hydrocortisone Injection

    MedlinePlus

    Hydrocortisone injection is used to treat symptoms of low corticosteroid levels (lack of certain substances that are usually produced ... also used to treat severe allergic reactions. Hydrocortisone injection is used in the management of multiple sclerosis ( ...

  14. Palivizumab Injection

    MedlinePlus

    Palivizumab injection is used to help prevent respiratory syncytial virus (RSV; common virus that can cause serious lung infections) ... or have certain heart or lung diseases. Palivizumab injection is not used to treat the symptoms of ...

  15. Naltrexone Injection

    MedlinePlus

    Naltrexone injection is used along with counseling and social support to help people who have stopped drinking large amounts of alcohol to avoid drinking again. Naltrexone injection is also used along with counseling and social ...

  16. Tesamorelin Injection

    MedlinePlus

    Tesamorelin injection is used to decrease the amount of extra fat in the stomach area in adults with human ... fat in certain areas of the body). Tesamorelin injection is not used to help with weight loss. ...

  17. Testosterone Injection

    MedlinePlus

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  18. Tigecycline Injection

    MedlinePlus

    Tigecycline injection used to treat certain serious infections including community acquired pneumonia (a lung infection that developed in a ... area between the chest and the waist). Tigecycline injection should not be used to treat pneumonia that ...

  19. Eculizumab Injection

    MedlinePlus

    Eculizumab injection is used to treat paroxysmal nocturnal hemoglobinuria (PNH: a type of anemia in which too many red ... oxygen to all parts of the body). Eculizumab injection is also used to treat atypical hemolytic uremic ...

  20. Pembrolizumab Injection

    MedlinePlus

    Pembrolizumab injection is used to treat melanoma (a type of skin cancer) that cannot be treated with surgery or ... spread to other parts of the body. Pembrolizumab injection is also used to treat a certain type ...

  1. Methylprednisolone Injection

    MedlinePlus

    ... allergic reactions. Methylprednisolone injection is used in the management of multiple sclerosis (a disease in which the ... laboratory test, tell your doctor and the laboratory personnel that you are using methylprednisolone injection.If you ...

  2. Obinutuzumab Injection

    MedlinePlus

    Obinutuzumab injection is used with chlorambucil (Leukeran) to treat chronic lymphocytic leukemia (CLL; a type of cancer of the white blood cells). Obinutuzumab injection is in a class of medications called ...

  3. Busulfan Injection

    MedlinePlus

    Busulfex® Injection ... Busulfan injection is used to treat a certain type of chronic myelogenous leukemia (CML; a type of cancer of ... of 16 doses) before bone marrow transplant.Busulfan injection may cause seizures during therapy with the medication. ...

  4. Design and performance of a new continuous-flow sample-introduction system for flame infrared-emission spectrometry: Applications in process analysis, flow injection analysis, and ion-exchange high-performance liquid chromatography.

    PubMed

    Lam, C K; Zhang, Y; Busch, M A; Busch, K W

    1993-06-01

    A new sample introduction system for the analysis of continuously flowing liquid streams by flame infrared-emission (FIRE) spectrometry has been developed. The system uses a specially designed purge cell to strip dissolved CO(2) from solution into a hydrogen gas stream that serves as the fuel for a hydrogen/air flame. Vibrationally excited CO(2) molecules present in the flame are monitored with a simple infrared filter (4.4 mum) photometer. The new system can be used to introduce analytes as a continuous liquid stream (process analysis mode) or on a discrete basis by sample injection (flow injection analysis mode). The key to the success of the method is the new purge-cell design. The small internal volume of the cell minimizes problems associated with purge-cell clean-out and produces sharp, reproducible signals. Spent analytical solution is continuously drained from the cell, making cell disconnection and cleaning between samples unnecessary. Under the conditions employed in this study, samples could be analyzed at a maximum rate of approximately 60/h. The new sample introduction system was successfully tested in both a process analysis- and a flow injection analysis mode for the determination of total inorganic carbon in Waco tap water. For the first time, flame infrared-emission spectrometry was successfully extended to non-volatile organic compounds by using chemical pretreatment with peroxydisulfate in the presence of silver ion to convert the analytes into dissolved carbon dioxide, prior to purging and detection by the FIRE radiometer. A test of the peroxydisulfate/Ag(+) reaction using six organic acids and five sugars indicated that all 11 compounds were oxidized to nearly the same extent. Finally, the new sample introduction system was used in conjunction with a simple filter FIRE radiometer as a detection system in ion-exchange high-performance liquid chromatography. Ion-exchange chromatograms are shown for two aqueous mixtures, one containing six organic

  5. INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: High-performance 1.3-μm InGaAsP/InP heterostructures formed by two-phase liquid epitaxy

    NASA Astrophysics Data System (ADS)

    Novotný, J.; Procházková, O.; Šrobár, F.; Zelinka, J.

    1988-11-01

    A description is given of a two-phase liquid epitaxy method used to grow InGaAsP/InP heterostructures intended for injection lasers emitting in the 1.3-μm range. A study was made of heterostructures of three types: double, with an additional quaternary layer (λ approx 1.1 μm) adjoining the active layer; with two quaternary layers between the active layer and the InP confining layers. The configuration with two flanking quaternary layers was found to be the best from the point of view of the threshold current density, optical output power, and reproducibility.

  6. [The influential factors of MOCVD growth of InP in opals].

    PubMed

    Tan, Chun-hua; Fan, Guang-han; Huang, Xu-guang

    2008-12-01

    The key problem of fabricating the 3-D InP inverse opal photonic crystal is to increase the loading of InP in opals. In the present paper, low-pressure metal-organic chemical-vapour deposition (MOCVD) was used to infill the voids within synthetic opals with InP. The morphologies and optical properties of SiO2-InP photonic crystal were characterized by scanning electron microscopy and ultraviolet-visible spectrophotometry (UV-Vis). Several series of experiments were carried out in order to analyze the factors that influence the loading of InP in opals and determine the optimal InP growth conditions. The results of optical experiments are in good agreement with those derived from the theoretical considerations: By increasing the extent of InP infilling within the voids, the extent of refractive index contrast between the silica spheres and the void as well as the extent of natural optical properties change of the photonic crystal were increased. Cycle growth, low-pressure growth, and using the match substrate and the same configuration character between SiOi and InP are beneficial to increaseing the extent of InP infilling within the opal voids. The process has been optimized to achieve SiO2-InP photonic crystal with higher loading of InP. The study provides a scientific basis for manufacturing three-dimensional InP inverse opal photonic crystals.

  7. DC characteristics improvement of recessed gate GaN-based HFETs grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Cheng, A. T.; Su, Y. K.; Lai, W. C.; Huang, C. H.

    2007-01-01

    The effect of the recessed gate structure on DC characteristics of n-channel depletion mode heterostructure field effect transistors (HFETs) grown by metalorganic chemical vapor deposition (MOCVD) was demonstrated. The recessed gate process was carried out by using photo-enhanced chemical (PEC) wet etching. There were improvements on the electrical characteristics after using the recessed gate AlGaN/GaN and AlGaN/GaN/InGaN/GaN HFET structures because of the better gate controllability to the drain current. It was also found that the gate voltage, VGS, of the transconductance peak value shifted toward positive bias for the recessed gate structure. The leakage current, the transconductance ( Gm) and the saturation current of the recessed gate AlGaN/GaN/InGaN/GaN HFET with a 30-nm-thick Si-doped GaN cap layer are 1.95 mA/mm, 94.82 mA/mm and 230 mA/mm, respectively. This performance is quite better than that of the device with no recessed gate structure.

  8. Temperature variations in electrical and photoluminescence properties of ZnSe grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Giapis, Konstantinos P.; Lu, Da-Chen; Jensen, Klavs F.; Potts, John E.

    1990-07-01

    The effect of growth temperature on the optoelectronic properties of epitaxial ZnSe grown by metalorganic chemical vapor deposition (MOCVD) on GaAs (100) from dimethyl zinc and hydrogen selenide has been investigated in a vertical reactor. Chlorine was found to be the main donor impurity originating from Se, used to produce the hydrogen selenide. The deposited films were single crystalline for growth temperatures above 225°C and were characterized by low-temperature photoluminescence. With increasing growth temperature, the donor-bound excitonic emission decreased in intensity and linewidth, while the 77 K electron mobility increased. The trend continued until the free exciton became the dominant near-band-edge emission at a growth temperature of 350°C, at which point the films turned out to be highly resistive and Hall measurements could not be performed. High electron mobilities of 8000-9000 cm 2/V·s at 77 K were measured for growth temperatures of 325°C. The transition tto high resistivity was found to be accompanied by a sharp increase in the photoluminescence intensity of the Y0 emission, related to extended defects. Thermally activated dislocations and changes in the charge state of the Y0-related defect are proposed as possible mechanisms for these experimental observations.

  9. Structural and optical properties of anatase TiO2 heteroepitaxial films prepared by MOCVD

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Feng, Xianjin; Xiao, Hongdi; Luan, Caina; Ma, Jin

    2016-11-01

    High-quality single-crystal anatase TiO2(a-TiO2) thin films have been obtained on SrTiO3 (STO) substrates using the metalorganic chemical vapor deposition (MOCVD) method. The optimal preparation process was explored. The lattice structure and epitaxial relationship were investigated by X-ray diffraction (XRD, both θ-2θ and Φ scans) and transmission electron microscopy (TEM). The results indicated that the film prepared at 550 °C with the Ti precursor molar flow rate of 4×10-7 mol/min had the best single crystalline quality, for which a clear epitaxial relationship of a-TiO2 (001)||STO (100) with a-TiO2 [100]||STO [001bar] could be inferred. The elemental composition and proportion were studied by the X-ray photoelectron spectroscopy (XPS) method, which proved the deposited film approximated stoichiometric TiO2. The samples showed high transparency of 70-80% in the visible range.

  10. Effect of Deposition Temperature on the Properties of TIO2 Thin Films Deposited by Mocvd

    NASA Astrophysics Data System (ADS)

    Khalifa, Zaki S.

    2016-02-01

    Crystal structure, microstructure, and optical properties of TiO2 thin films deposited on quartz substrates by metal-organic chemical vapor deposition (MOCVD) in the temperature range from 250∘C to 450∘C have been studied. The crystal structure, thickness, microstructure, and optical properties have been carried out using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), and UV-visible transmittance spectroscopy, respectively. XRD patterns show that the obtained films are pure anatase. Simultaneously, the crystal size calculated using XRD peaks, and the grain size measured by AFM decrease with the increase in deposition temperature. Moreover, the texture of the films change and roughness decrease with the increase in deposition temperature. The spectrophotometric transmittance spectra have been used to calculate the refractive index, extinction coefficient, dielectric constant, optical energy gap, and porosity of the deposited films. While the refractive index and dielectric constant decrease with the increase of deposition temperature, the porosity shows the opposite.

  11. Microstructure Characteristics of High Lift Factor MOCVD REBCO Coated Conductors With High Zr Content

    SciTech Connect

    Galstyan, E; Gharahcheshmeh, MH; Delgado, L; Xu, AX; Majkic, G; Selvamanickam, V

    2015-06-01

    We report the microstructural characteristics of high levels of Zr-added REBa2Cu3O7-x (RE = Gd, Y rare earth) coated conductors fabricated by Metal Organic Chemical Vapor Deposition (MOCVD). The enhancements of the lift factor defined as a ratio of the in-field (3 T, B parallel to c-axis) critical current density (J(c)) at 30 K and self-field J(c) at 77 K have been achieved for Zr addition levels of 20 and 25 mol% via optimization of deposition parameters. The presence of strong flux pinning is attributed to the aligned nanocolumns of BaZrO3 and nanoprecipitates embedded in REBa2Cu3O7-x matrix with good crystal quality. A high density of BZO nanorods with a typical size 6-8 nm and spacing of 20 nm has been observed. Moreover, the high Zr content was found to induce a high density of intrinsic defects, including stacking faults and dislocations. The correlation between in-field performance along the c-axis and microstructure of (Gd, Y) BCO film with a high level of Zr addition is discussed.

  12. EFFECTS OF Au ON THE GROWTH OF ZnO NANOSTRUCTURES ON Si BY MOCVD

    NASA Astrophysics Data System (ADS)

    Cong, Chen; Fan, Lu Yang; Ping, He Hai; Wei, Wu Ke; Zhen, Ye Zhi

    2013-06-01

    The effects of Au on the growth of ZnO nanostructures on Si by metal organic chemical vapor deposition (MOCVD) at a relatively low temperature (450°C) were investigated. The experimental results showed that Au nanoparticles played a critical role during the growth of the ZnO nanostructures and affected their morphology and optical properties. It was found that Au nanoparticles particularly affected the nucleation of ZnO nanostructures during the growth process and the Au-assisted growth mechanism of ZnO nanostructures should be ascribed to the vapor-solid (VS) mechanism. The formation of a nanoneedle may be attributed to a more reactive interface between Au and ZnO, which leads to more zinc gaseous species absorbed near the interface. Different nucleation sites on ZnO nuclei resulted in the disorder of ZnO nanoneedles. Moreover, the crystalline quality of nano-ZnO was improved due to the presence of Au, according to the smaller full width at half maximum (FWHM) of the low-temperature exciton emission. We confirmed that ZnO nanoneedles showed better crystalline quality than ZnO nanorods through the HRTEM images and the SAED patterns. The reason for the improvement of the crystalline quality of nano-ZnO may be due to the less lattice mismatch.

  13. Growth of GaAs in a rotating disk MOCVD reactor

    NASA Astrophysics Data System (ADS)

    Thompson, A. G.; Sundaram, V. S.; Girard, G. R.; Fraas, L. M.

    1989-04-01

    We report the growth of GaAs homoepitaxial films from trimethylgallium and arsine in a multi-wafer rotating disk reactor. In this configuration the substrates are mounted on a disk that is spun at high speed (> 1000 rpm) in a sub-atmospheric (<100 Torr) environment. The spinning disk pumps the reactant and carrier gases radially outwards; under optimum conditions, convective recirculating cells are avoided, thus facilitating rapid transitions in doping and composition in the grown layers. In this paper we look at the morphology, growth rate and electrical properties of the GaAs epitaxial layers as a function of substrate temperature, V/III ratio, dopant type, spin speed and hydrogen carrier flow conditions. These results are compared with those obtained in conventional MOCVD reactors. Silicon and tellurium doping over a wide range of carrier concentrations has been achieved with excellent mobilities and uniformity across the wafers. Preliminary results on MESFET's fabricated from n +/n/buffer structures show good device characteristics.

  14. Influence of AlN thickness on AlGaN epilayer grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Jayasakthi, M.; Juillaguet, S.; Peyre, H.; Konczewicz, L.; Baskar, K.; Contreras, S.

    2016-10-01

    AlGaN/AlN layers were grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. The AlN buffer thickness was varied from 400 nm to 800 nm. The AlGaN layer thickness was 1000 nm. The crystalline quality, thickness and composition of AlGaN were determined using high resolution X-ray diffraction (HRXRD). The threading dislocation density (TDD) was found to decrease with increase of AlN layer thickness. Reciprocal space mapping (RSM) was used to estimate the strain and relaxation between AlGaN and AlN. The optical properties of AlGaN layers were investigated by temperature dependent photoluminescence (PL). PL intensities of AlGaN layers increases with increasing the AlN thickness. The surface morphology of AlGaN was studied by atomic force microscopy (AFM). Root mean square (RMS) roughness values were found to be decreased while increase of AlN thickness.

  15. Process control of MOCVD growth for LEDs by in-situ photoluminescence

    NASA Astrophysics Data System (ADS)

    Prall, C.; Haberland, K.; Kaspari, C.; Brunner, F.; Weyers, M.; Rueter, D.

    2016-03-01

    Development and manufacturing of LED structures is still driven by production cost reduction and performance improvements. Therefore, in-situ monitoring during the epitaxial process plays a key role in view of further yield improvement and process optimization. With the continuing trend towards larger wafers, stronger bow and increased aspherical curvature are additional challenges the growers have to face, leading to non-uniform LED-emission. Compared to traditional in-situ metrology like curvature measurement and near UV pyrometry, in-situ photoluminescence measurements can provide a more direct access to the quantum well emission already during growth. In this paper we show how in-situ photoluminescence measurements can be used in a production type multi-wafer MOCVD system to characterize the quantum well emission already during growth. We also demonstrate how deviations from the desired wavelength can be detected and corrected in the same growth run. Since the method is providing spatially resolved line-scans across the wafer, also the uniformity of the emission wavelength can be characterized already during growth. Comparison of in-situ and ex-situ photoluminescence data show excellent agreement with respect to wavelength uniformity on 4 inch wafers.

  16. Studies on the effect of ammonia flow rate induced defects in gallium nitride grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Suresh, S.; Lourdudoss, S.; Landgren, G.; Baskar, K.

    2010-10-01

    Gallium nitride (GaN) epitaxial layers were grown with different V/III ratios by varying the ammonia (NH 3) flow rate, keeping the flow rate of the other precursor, trimethylgallium (TMG), constant, in an MOCVD system. X-ray rocking curve widths of a (1 0 2) reflection increase with an increase in V/III ratio while the (0 0 2) rocking curve widths decrease. The dislocation density was found to increase with an increase in ammonia flow rate, as determined by hot-wet chemical etching and atomic force microscopy. 77 K photoluminescence studies show near band emission at 3.49 eV and yellow luminescence peaking at 2.2 eV. The yellow luminescence (YL) intensity decreases with an increase in V/III ratio. Positron annihilation spectroscopy studies show that the concentration of Ga-like vacancies increases with an increase in ammonia flow rate. This study confirms that the yellow luminescence in the GaN arises due to deep levels formed by gallium vacancies decorated with oxygen atoms.

  17. MOCVD-growth of thin zinc oxide films from zinc acetylacetonate and air

    NASA Astrophysics Data System (ADS)

    Pflitsch, Christian; Nebatti, Abdelkader; Brors, Georg; Atakan, Burak

    2012-06-01

    The metalorganic chemical vapour deposition (MOCVD) of thin zinc oxide films on borosilicate glass and silicon substrates in a hot-wall CVD-reactor (HWR) was studied. Zinc acetylacetonate (Zn(acac)2) and air were used as precursors. The aim of this work was to optimize the deposition parameters, such as pressure and deposition temperature, with respect to the film quality, structure, and homogeneity. Most experiments were performed at atmospheric pressure; this approach avoids the usage of an expensive vacuum system. It turned out that polycrystalline zinc oxide is grown at deposition temperatures above 613 K. Above 823 K, they additionally are c-axis orientated. At atmospheric pressure and lower temperature (<773 K) the film deposition is homogeneously over the whole tube furnace while at higher temperature inhomogeneous film growth and particle formation are observed, indicating a shift of the growth mechanism to the diffusion controlled regime. Although the homogeneity is improved by using higher flow velocities at atmospheric pressure, particle growth cannot be suppressed. Only at reduced pressure, which was 200 mbar in the present case, the deposition at 823 K is kinetically controlled and without particle formation, resulting in the homogeneous growth of well adhering ZnO films with c-axis orientation.

  18. The controlled growth of GaN microrods on Si(111) substrates by MOCVD

    NASA Astrophysics Data System (ADS)

    Foltynski, Bartosz; Garro, Nuria; Vallo, Martin; Finken, Matthias; Giesen, Christoph; Kalisch, Holger; Vescan, Andrei; Cantarero, Andrés; Heuken, Michael

    2015-03-01

    In this paper, a selective area growth (SAG) approach for growing GaN microrods on patterned SiNx/Si(111) substrates by metal-organic chemical vapor deposition (MOCVD) is studied. The surface morphology, optical and structural properties of vertical GaN microrods terminated by pyramidal shaped facets (six { 10 1 bar 1} planes) were characterized using scanning electron microscopy (SEM), room temperature photoluminescence (PL) and Raman spectroscopy, respectively. Measurements revealed high-quality GaN microcolumns grown with silane support. Characterized structures were grown nearly strain-free (central frequency of Raman peak of 567±1 cm-1) with crystal quality comparable to bulk crystals (FWHM=4.2±1 cm-1). Such GaN microrods might be used as a next-generation device concept for solid-state lighting (SSL) applications by realizing core-shell InGaN/GaN multi-quantum wells (MQWs) on the n-GaN rod base.

  19. Effect of primary-zone water injection on pollutants from a combustor burning liquid ASTM A-1 and vaporized propane fuels

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.; Norgren, C. T.

    1973-01-01

    A combustor segment 0.457 meter (18 in.) long with a maximum cross section of 0.153 by 0.305 meter (6 by 12 in.) was operated at inlet-air temperatures of 590 and 700 K, inlet-air pressures of 4 and 10 atmospheres, and fuel-air ratios of 0.014 and 0.018 to determine the effect of primary-zone water injection on pollutants from burning either propane or ASTM A-1 fuel. At a simulated takeoff condition of 10 atmospheres and 700 K, multiple-orifice nozzles used to inject water at 1 percent of the airflow rate reduced nitrogen oxides 75 percent with propane and 65 percent with ASTM A-1 fuel. Although carbon monoxide and unburned hydrocarbons increased with water injection, they remained relatively low; and smoke numbers were well below the visibility limit.

  20. Water Injected Turbomachinery

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Shouse, D. T.; Roquemore, W. M.

    2005-01-01

    From antiquity, water has been a source of cooling, lubrication, and power for energy transfer devices. More recent applications in gas turbines demonstrate an added facet, emissions control. Fogging gas turbine inlets or direct injection of water into gas turbine combustors, decreases NOx and increases power. Herein we demonstrate that injection of water into the air upstream of the combustor reduces NOx by factors up to three in a natural gas fueled Trapped Vortex Combustor (TVC) and up to two in a liquid JP-8 fueled (TVC) for a range in water/fuel and fuel/air ratios.

  1. Peculiarities of photoluminescence of vertical n +/ n-GaAs/Al0.25Ga0.75As MBE- and MOCVD-grown structures designed for microwave detectors

    NASA Astrophysics Data System (ADS)

    Čerškus, Aurimas; Kundrotas, Jurgis; Sužiedėlis, Algirdas; Gradauskas, Jonas; Ašmontas, Steponas; Johannessen, Eric; Johannessen, Agne

    2015-09-01

    Vertical MBE- and MOCVD-grown structures used for microwave electronics have been studied with continuous wave and time-correlated single photon counting dynamic photoluminescence technique. The photoluminescence spectra and light emission lifetimes are used to explain the recombination mechanisms of the excited carriers. This paper presents results showing the differences in recombination characteristics of layers grown using MBE process compared with MOCVD process. One of these differences is that the PL spectrum of the MOCVD-grown layer is shifted towards the forbidden energy gap region, as well as the characteristic recombination time is longer than for the MBE-grown sample. This peculiarity can be attributed to the formation of the localised band tails in the MOCVD-grown sample. The proposed analytical model explains the differences in microwave detection properties of the samples grown by MBE and MOCVD processes.

  2. InGaAs/InP PIN photodetector arrays made by MOCVD based zinc diffusion processes

    NASA Astrophysics Data System (ADS)

    Islam, Mohammad; Feng, J. Y.; Berkovich, Andrew; Abshire, Pamela; Barrows, Geoffrey; Choa, Fow-Sen

    2016-05-01

    InGaAs based long-wavelength near infrared detector arrays are very important for high dynamic range imaging operations seamlessly from daylight environments to dark environments. These detector devices are usually made by open-hole diffusion technique which has the advantage of lower leakage current and higher reliability. The diffusion process is usually done in a sealed quartz ampoule with dopant compounds like ZnP2, ZnAs3, CdP2 etc. side by side with semiconductor samples. The ampoule needs to be prepared and sealing process needs to be done in very clean environment and each time can have variations. In this work we demonstrated using MOCVD growth chamber to perform the diffusion process. The advantages of such a process are that the tool is constantly kept in ultra clean environment and can reproducibly provide clean processes without introducing unexpected defects. We can independently control the temperature and flow rate of the dopant - they are not linked as in the ampoule diffusion case. The process can be done on full wafers with good uniformity through substrate rotation, which is good for large detector array fabrications. We have fabricated different types of InGaAs/InP detector arrays using dimethyl zinc as the dopant source and PH3 or AsH3 for surface protection. Pre-studies of Zn-diffusion profiles in InGaAs and InP at different temperatures, flow rates, diffusion times and followed annealing times were conducted to obtain good control of the process. Grown samples were measured by C-V profilometer to evaluate the diffusion depth and doping concentration. The dependence of the diffusion profile with temperature, dopant partial pressures, and annealing temperature and time and some of the fabricated device characteristics are reported.

  3. Study of carrier recombination transient characteristics in MOCVD grown GaN dependent on layer thickness

    SciTech Connect

    Gaubas, E. Čeponis, T.; Jasiunas, A.; Jelmakas, E.; Juršėnas, S.; Kadys, A.; Malinauskas, T.; Tekorius, A.; Vitta, P.

    2013-11-15

    The MOCVD grown GaN epi-layers of different thickness have been examined in order to clarify a role of surface recombination, to separate an impact of radiative and non-radiative recombination and disorder factors. The microwave probed –photoconductivity (MW-PC) and spectrally resolved photo-luminescence (PL) transients were simultaneously recorded under ultraviolet (UV) light 354 nm pulsed 500 ps excitation. The MW-PC transients exhibited the carrier decay components associated with carrier decay within micro-crystals and the disordered structure on the periphery areas surrounding crystalline columns. Three PL bands were resolved within PL spectrum, namely, the exciton ascribed UV-PL band edge for hν>3.3 eV, blue B-PL band for 2.5 < hν < 3.0 eV and yellow Y-PL band with hν < 2.4 eV. It has been obtained that intensity of UV-PL band increases with excitation density, while intensity of B-PL band is nearly invariant. However, intensity of the Y-PL increases with reduction of the excitation density. The Y-PL can be associated with trapping centers. A reduction of UV excitation density leads to a decrease of the relative amplitude of the asymptotic component within the MW-PC transients and to an increase of the amplitude as well as duration of the yellow spectral band (Y-PL) asymptotic component. Fractional index α with values 0.5 < α < 0.8 was evaluated for the stretched-exponent component which fits the experimental transients determined by the disordered structure ascribed to the periphery areas surrounding the crystalline columns.

  4. Characterization of Defects on MOCVD Grown Gallium Nitride Using Transient Analysis Techniques

    NASA Astrophysics Data System (ADS)

    Kasani, Sujan Phani Kumar

    Since the invention of the first visible spectrum (red) LED by Holonyak in 1962, there has been a need for more efficient, more reliable and less expensive LEDs. The III-nitrides revolutionized semiconductor technology with their applications in the blue LED's. However the internal quantum efficiency of LED's are limited by the deep level traps in GaN substrate. Traps are defects in the crystal lattice, which depends on growth parameters. These traps act as non-radiative centers where non-radiative recombination occurs without conversion of available energy into light. Characterization of these traps in a material is necessary for better understanding of the material growth quality and resulting device performance. In this work Capacitance-Voltage (C-V) and Deep Level Transient Spectroscopy (DLTS) are conducted which provide electronic properties of trap centers like activation energy, doping concentration and capture cross-section. In n-GaN grown by Metalorganic Chemical Vapor Deposition (MOCVD) on Sapphire two defects types are detected and are characterized by Capacitance-Voltage and Deep Level Transient Spectroscopy. Two deep levels E1 and E2 are typically observed in n-GaN with the activation energies of 0.21eV and 0.53eV at 125°K and 325°K, respectively. The deep level E1 is caused by linear line defects along dislocation cores while deep level E2 is related to point defects. The characterization techniques, experimental systems and preliminary characterization results are discussed in detail.

  5. Doubly charged state of EL2 defect in MOCVD-grown GaAs

    NASA Astrophysics Data System (ADS)

    Naz, Nazir A.; Qurashi, Umar S.; Majid, Abdul; Zafar Iqbal, M.

    2007-12-01

    EL2 is the ubiquitous native defect in crystalline GaAs grown by a variety of different techniques. It has been proposed to be a doubly charged deep-level center with two states having distinct energy levels in the band gap. While the singly charged state has been the subject of many experimental studies and is, therefore, well established, the doubly charged state has only been occasionally alluded to in the literature. This paper provides evidence for a dominant inadvertent deep level in p-type GaAs most likely to be the doubly charged state of the EL2 center. Deep-level transient spectroscopy (DLTS) has been applied to characterize epitaxial layers of p-type GaAs grown on p + GaAs substrates by low-pressure metal organic chemical vapor deposition (LP-MOCVD). A pronounced peak is observed in the majority carrier (hole) emission deep-level spectra. Thermal emission rate of holes from the corresponding deep level is found to exhibit a strong electric field dependence, showing an increase of more than two orders of magnitude with an increase of the electric field by a factor of ∼2. The thermal activation energy for this level is found to vary from 0.29 to 0.61 eV as the electric field is varied from 2.8×10 5 to 1.4×10 5 V/cm. Direct pulse-filling measurements point to a temperature-dependent behavior of the hole capture cross section of this level. We identify this inadvertent deep-level defect, commonly observed in p-type GaAs grown by a variety of different methods, with the doubly charged state of the well-known As Ga antisite related defect, EL2.

  6. Microwave characterization of normal and superconducting states of MOCVD made YBCO tapes

    NASA Astrophysics Data System (ADS)

    Wosik, Jarek; Krupka, Jerzy; Qin, Kuang; Ketharnath, Dhivya; Galstyan, Eduard; Selvamanickam, Venkat

    2017-03-01

    We have used a microwave, non-contact, non-destructive, dielectric resonator (DR) technique to characterize complex conductivity of different quality YBCO/Hastelloy tapes for the purpose of exploring such a technique as a potential quality control method for fabrication of YBCO tapes. The tapes were deposited at different temperatures on Hastelloy-supported oxide buffer layers using the MOCVD technique. The buffer stack consisted of aluminum oxide (Al2O3), yttrium oxide (Y2O3), and textured ion beam assisted deposition-MgO and LaMnO3 layers. Two dielectric resonators (DRs), the single post DR, consisting of high-permittivity barium zirconium titanate ceramic operating at 13 GHz in quasi-TE01δ mode, and the rod DR, consisting of rutile single crystal disk operating at 9.4 GHz in-TE011 mode, were designed to meet sensitivity requirements for characterization of conductivity of the superconductor at normal and superconducting states, respectively. For calculations of complex conductivity from experimental data of Q-factor and resonant frequency shift, a commercial electromagnetic simulator HFSS, based on finite elements analysis, was used. The theoretical Q-factor and resonant frequency on conductivity functions obtained from full wave numerical simulations of microwave fields were matched with the experimental data to determine conductivity of the YBCO tapes in both normal and superconducting states. In addition, for comparison purposes, 280 nm thick high-quality YBCO epitaxial film deposited on a dielectric substrate was also characterized, including frequency dependence of the complex conductivity. Discussion about feasibility of using DR microwave techniques as a quality control tool via measurements of conductivity versus temperature slope of the YBCO/Hastelloy tape in normal state is included. Also, microwave conductivity values of Hastelloy substrate as a function of temperature are reported.

  7. Fabrication of InGaN quantum dots by periodically interrupted growth in MOCVD

    NASA Astrophysics Data System (ADS)

    Choi, Seung-Kyu; Jang, Jae-Min; Yi, Sung-Hak; Kim, Jung-A.; Jung, Woo-Gwang

    2008-03-01

    Self-assembled InGaN quantum dots are fabricated in a two-flow horizontal MOCVD reactor maintained at the pressure of 200 torr. The precursors were trimethyl-gallium (TMG) and trimethyl-indium (TMI) and ammonia (NH 3), and the carrier gas was N II and H II. The optimum condition for periodically interrupted growth (PIG) mode was deduced to fabricate the InGaN quantum dots. NH 3 was supplied in PIG mode with the interval of 3 seconds and 5 seconds while TMG and TMI were supplied continuously. The carrier gas was N II in QDs growth, while H II in nucleation and buffer layer growth. The influence of number of periodic interrupted NH 3 on the structural and optical properties of InGaN quantum dots was investigated by AFM, FE-SEM and low temperature photoluminescence (LT-PL). The AFM images give the size of InGaN QDs with diameter of 20 ~ 50 nm, height of 3 ~ 10 nm and density of 10 10 #/cm2 ~ 10 11 #/cm2. A strong peak at 362.2 nm (3.41eV) and broad emission peak in 435 nm (2.86 eV) were evolved in the photoluminescence measurement using Nd-YAG laser. The composition of QDs was estimated to be In 0.14Ga 0.86N from the relation between peak energy and indium content. Hence. The periodic interruption growth enables the fabrication of self- assembled InGaN QDs with high density and uniform size.

  8. Nitrous oxide emissions in Midwest US maize production vary widely with band-injected liquid N fertilizer rates, timing and nitrapyrin presence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrification inhibitors have potential to reduce N2O emissions from maize fields. A new micro-encapsulated formulation of nitrapyrin, optimized to be used with liquid fertilizers became available to US farmers in 2010. Our objectives were to: i) 15assess the impacts of urea-ammonium nitrate (UAN) m...

  9. Musculoskeletal Injection

    PubMed Central

    Wittich, Christopher M.; Ficalora, Robert D.; Mason, Thomas G.; Beckman, Thomas J.

    2009-01-01

    Patients commonly present to primary care physicians with musculoskeletal symptoms. Clinicians certified in internal medicine must be knowledgeable about the diagnosis and management of musculoskeletal diseases, yet they often receive inadequate postgraduate training on this topic. The musculoskeletal problems most frequently encountered in our busy injection practice involve, in decreasing order, the knees, trochanteric bursae, and glenohumeral joints. This article reviews the clinical presentations of these problems. It also discusses musculoskeletal injections for these problems in terms of medications, indications, injection technique, and supporting evidence from the literature. Experience with joint injection and the pharmacological principles described in this article should allow primary care physicians to become comfortable and proficient with musculoskeletal injections. PMID:19720781

  10. Rapid determination of 30 bioactive constituents in XueBiJing injection using ultra high performance liquid chromatography-high resolution hybrid quadrupole-orbitrap mass spectrometry coupled with principal component analysis.

    PubMed

    Zuo, Lihua; Sun, Zhi; Hu, Yurong; Sun, Ya; Xue, Wenhua; Zhou, Lin; Zhang, Jun; Bao, Xiaoyue; Zhu, Zhenfeng; Suo, Guanglu; Zhang, Xiaojian

    2017-04-15

    Xuebijing injection (XBJ) is a traditional Chinese herbal prescription widely used in the treatment of sepsis. Extensive chemical studies revealed that XBJ injection contains amino acids, phenolic acids, flavonoid glycosides, terpeneglycosides and phthalides. In this study, the applicability of ultra high performance liquid chromatography coupled with high resolution hybrid quadruple-orbitrap mass spectrometry (UHPLC-Q-Orbitrap MS) for the simultaneous quantitative analysis of 30 bioactive constituents in XueBiJing injection (XBJ) was investigated. The mass spectrometer was operated in full MS scan mode. The use of 70,000FWHM mass resolution and narrow mass windows (5ppm) could effectively improve the selectivity of the method. Separation was achieved on a Waters ACQUITY UPLC(®) HSS C18 column (2.1mm×100mm, 1.8μm) with a gradient mobile phase consisting of acetonitrile-water (containing 10mM ammonium acetate) at a flow rate of 0.2mL/min. Satisfactory linearity was achieved within wide linear range and all correlation coefficients (r) of analytes were more than 0.9996. The limits of detection (LODs) were in the range of 0.1180-27.82ng/mL for different analytes. The relative standard deviations (RSDs) of inter- and intra-day precisions were less than 3.0% and the recoveries of the assay were in the range of 98.5%-101.5%. The validated method was successfully applied for simultaneous determination of 30 bioactive compounds in XueBiJing injection from 10 batches samples by UHPLC-Q-Orbitrap MS within 10min. Moreover, the results were evaluated principal component analysis and two compounds might be the most important chemical markers for chemical quality control of XBJ injection. The novel Q-Orbitrap mass spectrometry has been proved to be a very promising and powerful tool for routine screening of bioactive compounds in traditional Chinese medicine injection, ensuring drug safety and public health.

  11. Growth and conduction mechanism of As-doped p-type ZnO thin films deposited by MOCVD

    SciTech Connect

    Ma, Y.; Gao, Q.; Wu, G.G.; Li, W.C.; Gao, F.B.; Yin, J.Z.; Zhang, B.L.; Du, G.T.

    2013-03-15

    Highlight: ► P-type As-doped ZnO thin films was fabricated by MOCVD after post-growth annealing. ► The formation mechanism of p-ZnO with high hole concentration above 10{sup 19} cm{sup −3} was elucidated. ► Besides As{sub Zn}–2V{sub Zn} complex, C impurities also played an important role in realizing p-ZnO. ► The formations of As{sub O} and O-C-O complex were partially contributed to the p-type ZnO: As films. - Abstract: As-doped p-type ZnO thin films were fabricated by metal organic chemical vapor deposition (MOCVD) after in situ annealing in a vacuum. The p-type conduction mechanism was suggested by the analysis of X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy. It was found that most of the As dopants in p-ZnO thin films formed As{sub Zn}–2V{sub Zn} shallow acceptor complex, simultaneously, carbon impurities also played an important role in realizing p-type conductivity in ZnO. Substitutional carbon on oxygen site created passivated defect bands by combining with Ga atoms due to the donor-acceptor pair Coulomb binding, which shifted the valence-band maximum upwards for ZnO and thus increased the hole concentration.

  12. Influence of Mg and In on defect formation in GaN; bulk and MOCVD grown samples

    SciTech Connect

    Liliental-Weber, Z.; Benamara, M.; Jasinski, J.; Swider, W.; Washburn, J.; Grzegory, I.; Porowski, S.; Bak-Misiuk, J.; Domagala, J.; Bedair, S.; Eiting, C.J.; Dupuis, R.D.

    2000-11-22

    Transmission electron microscopy studies were applied to study GaN crystals doped with Mg. Both: bulk GaN:Mg crystals grown by a high pressure and high temperature process and those grown by metal-organic chemical-vapor deposition (MOCVD) have been studied. Structural dependence on growth polarity was observed in the bulk crystals. Spontaneous ordering (formation of polytypoids) was observed for growth in the N to Ga polar direction (N polarity). On the opposite site of the crystal (growth in the Ga to N polar direction) Mg-rich pyramidal defects with base on the basal planes and with walls inclined about 45O to these planes, empty inside (pinholes) were observed. A high concentration of these pyramidal defects was also observed in the MOCVD grown crystals. For samples grown with Mg delta doping planar defects were also observed especially at the early stages of growth followed by formation of pyramidal defects. TEM and x-ray studies of InxGa{sub 1{minus}x}N crystals for the range of 28-45% nominal In concentration shows formation of two sub-layers: strained and relaxed, with a much lower In concentration in the strained layer. Layers with the highest In concentration were fully relaxed.

  13. DLTS study of n-type GaN grown by MOCVD on GaN substrates

    NASA Astrophysics Data System (ADS)

    Tokuda, Y.; Matsuoka, Y.; Ueda, H.; Ishiguro, O.; Soejima, N.; Kachi, T.

    2006-10-01

    Electron traps in n-type GaN layers grown homoepitaxially by MOCVD on free-standing GaN substrates have been characterized using DLTS for vertical Schottky diodes. Two free-standing HVPE GaN substrates (A and B), obtained from two different sources, are used. The Si-doped GaN layers with the thickness of 5 μm are grown on an area of 0.9×0.9 cm 2 of substrate A and on an area of 1×1 cm 2 of substrate B. Two traps labeled B1 (Ec-0.23 eV) and B2 (Ec-0.58 eV) are observed with trap B2 dominant in GaN on both substrates. There exist no dislocation-related traps which have been previously observed in MOCVD GaN on sapphire. This might be correlated to the reduction in dislocation density due to the homoepitaxial growth. However, it is found that there is a large variation, more than an order of magnitude, in trap B2 concentration and that the B2 spatial distributions are different between the two substrates used.

  14. Status of HgCdTe Barrier Infrared Detectors Grown by MOCVD in Military University of Technology

    NASA Astrophysics Data System (ADS)

    Kopytko, M.; Jóźwikowski, K.; Martyniuk, P.; Gawron, W.; Madejczyk, P.; Kowalewski, A.; Markowska, O.; Rogalski, A.; Rutkowski, J.

    2016-09-01

    In this paper we present the status of HgCdTe barrier detectors with an emphasis on technological progress in metalorganic chemical vapor deposition (MOCVD) growth achieved recently at the Institute of Applied Physics, Military University of Technology. It is shown that MOCVD technology is an excellent tool for HgCdTe barrier architecture growth with a wide range of composition, donor /acceptor doping, and without post-grown annealing. The device concept of a specific barrier bandgap architecture integrated with Auger-suppression is as a good solution for high-operating temperature infrared detectors. Analyzed devices show a high performance comparable with the state-of-the-art of HgCdTe photodiodes. Dark current densities are close to the values given by "Rule 07" and detectivities of non-immersed detectors are close to the value marked for HgCdTe photodiodes. Experimental data of long-wavelength infrared detector structures were confirmed by numerical simulations obtained by a commercially available software APSYS platform. A detailed analysis applied to explain dark current plots was made, taking into account Shockley-Read-Hall, Auger, and tunneling currents.

  15. New approach to large-volume injection in reversed-phase high performance liquid chromatography: determination of atrazine and hydroxyatrazine in soil samples.

    PubMed

    Hutta, Milan; Chalányová, Mária; Halko, Radoslav; Góra, Róbert; Rybár, Ivan; Pajchl, Marek; Dokupilová, Svetlana

    2006-08-01

    A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow-rate setting accuracy of +/- 1-2% over a flow-rate range from 0.1 mL/min to 10 mL/min and the flow stability is 0.2% or less. Quarternary low pressure gradient pumps are widely available and used, but all their hydraulic lines are seldom utilised. The idea of using one line of a common commercial HPLC quaternary low-pressure pump for direct on-column injection (pumping) of large sample volumes ranging from 1 mL to 100 mL was tested. This approach was evaluated during practical work on the development of an RP-HPLC method of determination of residual atrazine and hydroxyatrazine. In lysimetric environmental experiments hydroxyatrazine was formed in situ in a soil column by hydrolysis of atrazine. The results proved the applicability of this approach not only in experiments with model mixtures of analytes at microg/L levels in solutions. Analysis of 20 mL of soil leachates and extracts of soil samples containing atrazine and hydroxyatrazine at the 10 microg/kg level (in dry soil) revealed that good figures-of-merit were preserved, even in the presence of a large excess of humic substances.

  16. Rapid isolation of biomarkers for compound specific radiocarbon dating using high-performance liquid chromatography and flow injection analysis-atmospheric pressure chemical ionisation mass spectrometry.

    PubMed

    Smittenberg, Rienk H; Hopmans, Ellen C; Schouten, Stefan; Sinninghe Damsté, Jaap S

    2002-11-29

    Repeated semi-preparative normal-phase HPLC was performed to isolate selected biomarkers from sediment extracts for radiocarbon analysis. Flow injection analysis-mass spectrometry was used for rapid analysis of collected fractions to evaluate the separation procedure, taking only 1 min per fraction. In this way 100-1000 microg of glycerol dialkyl glycerol tetraethers, sterol fractions and chlorophyll-derived phytol were isolated from typically 100 g of marine sediment, i.e., in sufficient quantities for radiocarbon analysis, without significant carbon isotopic fractionation or contamination.

  17. Certolizumab Injection

    MedlinePlus

    ... has not improved when treated with other medications, rheumatoid arthritis (a condition in which the body attacks its ... continues. When certolizumab injection is used to treat rheumatoid arthritis, it is usually given every other week and ...

  18. Natalizumab Injection

    MedlinePlus

    ... prevent episodes of symptoms in people who have Crohn's disease (a condition in which the body attacks the ... If you are receiving natalizumab injection to treat Crohn's disease, your symptoms should improve during the first few ...

  19. Vedolizumab Injection

    MedlinePlus

    ... injection may cause serious allergic reactions during an infusion and for several hours afterward. A doctor or ... of the following symptoms during or after your infusion: rash; itching; swelling of the face, eyes, mouth, ...

  20. Methotrexate Injection

    MedlinePlus

    ... woman's uterus while she is pregnant), breast cancer, lung cancer, certain cancers of the head and neck; certain ... Methotrexate injection is also used along with rest, physical therapy and ... treat rheumatoid arthritis by decreasing the activity of the immune system.

  1. Alirocumab Injection

    MedlinePlus

    ... injection is used along with diet and certain cholesterol-lowering medications (HMG-CoA reductase inhibitors [statins]) in ... familial heterozygous hypercholesterolemia (an inherited condition in which cholesterol cannot be removed from the body normally) or ...

  2. Evolocumab Injection

    MedlinePlus

    ... injection is used along with diet and certain cholesterol-lowering medications, HMG-CoA reductase inhibitors (statins), in ... heterozygous hypercholesterolemia (HeFH; an inherited condition in which cholesterol cannot be removed from the body normally) or ...

  3. Pentamidine Injection

    MedlinePlus

    Pentamidine injection is used to treat pneumonia caused by a fungus called Pneumocystis carinii. It is in a class of medications called antiprotozoals. It works by stopping the growth of protozoa that can cause pneumonia.

  4. Oxytocin Injection

    MedlinePlus

    Oxytocin injection is used to begin or improve contractions during labor. Oxytocin also is used to reduce bleeding after childbirth. ... other medications or procedures to end a pregnancy. Oxytocin is in a class of medications called oxytocic ...

  5. Ibritumomab Injection

    MedlinePlus

    ... is in a class of medications called monoclonal antibodies with radioisotopes. It works by attaching to cancer ... you receive ibritumomab injection, your body may develop antibodies (substances in the blood that help the immune ...

  6. Ganciclovir Injection

    MedlinePlus

    ... problems, eye problems other than CMV retinitis, or kidney disease.tell your doctor if you are pregnant or plan to become pregnant. Ganciclovir injection may cause infertility (difficulty becoming pregnant). However, if you are a ...

  7. Bendamustine Injection

    MedlinePlus

    ... a type of cancer of the white blood cells). Bendamustine injection is also used to treat a ... that begins in a type of white blood cell that normally fights infection) that is slow spreading, ...

  8. Vancomycin Injection

    MedlinePlus

    ... medications called glycopeptide antibiotics. It works by killing bacteria that cause infections.Antibiotics such as vancomycin injection ... infection may not be completely treated and the bacteria may become resistant to antibiotics.

  9. Levofloxacin Injection

    MedlinePlus

    ... of antibiotics called fluoroquinolones. It works by killing bacteria that cause infections.Antibiotics such as levofloxacin injection ... infection may not be completely treated and the bacteria may become resistant to antibiotics.

  10. Doxycycline Injection

    MedlinePlus

    ... medications called tetracycline antibiotics. It works by killing bacteria that cause infections.Antibiotics such as doxycycline injection ... infection may not be completely treated and the bacteria may become resistant to antibiotics.

  11. Sumatriptan Injection

    MedlinePlus

    ... accompanied by nausea and sensitivity to sound and light). Sumatriptan injection is also used to treat the ... children. Store it at room temperature, away from light, excess heat, and moisture (not in the bathroom). ...

  12. Alemtuzumab Injection

    MedlinePlus

    ... injection, the medication is usually given three times weekly on alternate days (usually Monday, Wednesday, and Friday) ... that you eat foods that are rich in iron such as meats, leafy green vegetables, and fortified ...

  13. Epinephrine Injection

    MedlinePlus

    Epinephrine injection is used along with emergency medical treatment to treat life-threatening allergic reactions caused by ... or stings, foods, medications, latex, and other causes. Epinephrine is in a class of medications called alpha- ...

  14. Mitoxantrone Injection

    MedlinePlus

    ... medications to relieve pain in people with advanced prostate cancer who did not respond to other medications. Mitoxantrone ... doses). When mitoxantrone injection is used to treat prostate cancer, it is usually given once every 21 days. ...

  15. Trastuzumab Injection

    MedlinePlus

    ... with other medications to treat certain types of stomach cancer that have spread to other parts of the ... weeks. When trastuzumab injection is used to treat stomach cancer, it is usually given once every 3 weeks. ...

  16. Topotecan Injection

    MedlinePlus

    ... organs where eggs are formed) and small cell lung cancer (a type of cancer that begins in the ... topotecan injection is used to treat ovarian or lung cancer, it is usually given once a day for ...

  17. Palonosetron Injection

    MedlinePlus

    ... that may occur several days after receiving certain chemotherapy medications. Palonosetron injection is in a class of medications called 5-HT3 receptor antagonists. It works by blocking the action of serotonin, a natural ...

  18. Meropenem Injection

    MedlinePlus

    ... skin and abdominal (stomach area) infections caused by bacteria and meningitis (infection of the membranes that surround ... of medications called antibiotics. It works by killing bacteria that cause infection.Antibiotics such as meropenem injection ...

  19. Amikacin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that ... medications called aminoglycoside antibiotics. It works by killing bacteria.Antibiotics such as amikacin injection will not work ...

  20. Ertapenem Injection

    MedlinePlus

    ... abdominal (stomach area) infections, that are caused by bacteria. It is also used for the prevention of ... medications called carbapenem antibiotics. It works by killing bacteria.Antibiotics such as ertapenem injection will not work ...

  1. Moxifloxacin Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria such as pneumonia; ; and , skin, and abdominal (stomach ... antibiotics called fluoroquinolones. It works by killing the bacteria that cause infections.Antibiotics such as moxifloxacin injection ...

  2. Cefepime Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria including pneumonia, and skin, urinary tract, and kidney ... medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as cefepime injection will not work ...

  3. Cefazolin Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria including skin, bone, joint, genital, blood, heart valve, ... medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as cefazolin injection will not work ...

  4. Daptomycin Injection

    MedlinePlus

    ... blood infections or serious skin infections caused by bacteria. Daptomycin injection is in a class of medications called cyclic lipopeptide antibiotics. It works by killing bacteria. Antibiotics will not work for treating colds, flu, ...

  5. Aztreonam Injection

    MedlinePlus

    ... to treat certain infections that are caused by bacteria, including respiratory tract (including pneumonia and bronchitis), urinary ... abdominal (stomach area) infections, that are caused by bacteria. Aztreonam injection also may be used before, during, ...

  6. Ceftazidime Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria including pneumonia and other lower respiratory tract (lung) ... medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as ceftazidime injection will not work ...

  7. Tobramycin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that ... medications called aminoglycoside antibiotics. It works by killing bacteria.Antibiotics such as tobramycin injection will not work ...

  8. Ciprofloxacin Injection

    MedlinePlus

    ... is used to treat certain infections caused by bacteria such as pneumonia; and infections of the skin, ... of antibiotics called fluoroquinolones. It works by killing bacteria that cause infections.Antibiotics such as ciprofloxacin injection ...

  9. Gentamicin Injection

    MedlinePlus

    ... treat certain serious infections that are caused by bacteria such as meningitis (infection of the membranes that ... medications called aminoglycoside antibiotics. It works by killing bacteria.Antibiotics such as gentamicin injection will not work ...

  10. Ceftaroline Injection

    MedlinePlus

    ... infections and pneumonia (lung infection) caused by certain bacteria. Ceftaroline is in a class of medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as ceftaroline injection will not work ...

  11. Daclizumab Injection

    MedlinePlus

    ... course of disease where symptoms flare up from time to time) of multiple sclerosis (MS; a disease in which ... injections. Before you use daclizumab yourself the first time, read the written instructions that come with it. ...

  12. Risperidone Injection

    MedlinePlus

    ... release (long-acting) injection is used to treat schizophrenia (a mental illness that causes disturbed or unusual ... do not already have diabetes. If you have schizophrenia, you are more likely to develop diabetes than ...

  13. Acyclovir Injection

    MedlinePlus

    ... chickenpox in the past) in people with weak immune systems. It is also used to treat first-time ... from time to time) in people with normal immune systems. Acyclovir injection is used to treat herpes simplex ...

  14. Omalizumab Injection

    MedlinePlus

    ... steroids. Omalizumab is also used to treat chronic hives without a known cause that cannot successfully be ... is not used to treat other forms of hives or allergic conditions. Omalizumab injection is in a ...

  15. Pegloticase Injection

    MedlinePlus

    ... doctor if you have glucose-6-phosphate dehydrogenase (G6PD) deficiency (an inherited blood disease). Your doctor may test you for G6PD deficiency before you start to receive pegloticase injection. If ...

  16. Lacosamide Injection

    MedlinePlus

    ... with other medications to control certain types of seizures in people who cannot take oral medications. Lacosamide ... If you suddenly stop using lacosamide injection, your seizures may happen more often. Your doctor will probably ...

  17. Oxacillin Injection

    MedlinePlus

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to oxacillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin, cefdinir, ...

  18. Nafcillin Injection

    MedlinePlus

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to nafcillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin, cefdinir, ...

  19. Ampicillin Injection

    MedlinePlus

    ... injection is in a class of medications called penicillins. It works by killing bacteria.Antibiotics such as ... and pharmacist if you are allergic to ampicillin; penicillins; cephalosporin antibiotics such as cefaclor, cefadroxil, cefazolin (Ancef, ...

  20. Naloxone Injection

    MedlinePlus

    ... emergency medical treatment to reverse the life-threatening effects of a known or suspected opiate (narcotic) overdose. ... is also used after surgery to reverse the effects of opiates given during surgery. Naloxone injection is ...

  1. Omacetaxine Injection

    MedlinePlus

    ... or cannot take these medications due to side effects. Omacetaxine injection is in a class of medications ... a treatment cycle if you experience serious side effects of the medication or if blood tests show ...

  2. Methylnaltrexone Injection

    MedlinePlus

    ... injection is used to treat constipation caused by opioid (narcotic) pain medications in patients with chronic (on-going) pain that is not caused by ... by protecting the bowel from the effects of opioid (narcotic) medications.

  3. Denosumab Injection

    MedlinePlus

    ... menstrual periods), who have an increased risk for fractures (broken bones) or who cannot take or did ... receiving certain treatments that increase their risk for fractures. Denosumab injection (Xgeva) is used to reduce fractures ...

  4. Rasburicase Injection

    MedlinePlus

    ... break down) in people with certain types of cancer who are being treated with chemotherapy medications. Rasburicase injection is in a class of medications called enzymes. It works by breaking down uric acid so that the body can eliminate it.

  5. Gemcitabine Injection

    MedlinePlus

    ... with surgery. Gemcitabine is also used to treat cancer of the pancreas that has spread to other parts of the ... 4 weeks. When gemcitabine is used to treat cancer of pancreas it may be injected once every week. The ...

  6. Doxercalciferol Injection

    MedlinePlus

    Doxercalciferol injection is used to treat secondary hyperparathyroidism (a condition in which the body produces too much parathyroid hormone [PTH; a natural substance needed to control the amount of calcium in ...

  7. Granisetron Injection

    MedlinePlus

    ... that may occur after surgery. Granisetron extended-release (long-acting) injection is used with other medications to prevent nausea and vomiting caused by cancer chemotherapy that may occur immediately ...

  8. Fluconazole Injection

    MedlinePlus

    ... injection is used to treat fungal infections, including yeast infections of the mouth, throat, esophagus (tube leading ... by fungus. Fluconazole is also used to prevent yeast infections in patients who are likely to become ...

  9. Docetaxel Injection

    MedlinePlus

    ... allergic to docetaxel injection or drugs made with polysorbate 80, an ingredient found in some medications. Ask ... if a medication you are allergic to contains polysorbate 80. If you experience any of the following ...

  10. Haloperidol Injection

    MedlinePlus

    ... emotions). Haloperidol injection is also used to control motor tics (uncontrollable need to repeat certain body movements) ... people who have Tourette's disorder (condition characterized by motor or verbal tics). Haloperidol is in a class ...

  11. Injection overview

    SciTech Connect

    Prestwich, S.

    1983-12-01

    The test program was initiated at the Raft River Geothermal Field in southern Idaho in September 1982. A series of eight short-term injection and backflow tests, followed by a long-term injection test, were conducted on one well in the field. Tracers were added during injection and monitored during backflow as well. The principal objective was to determine if tracers could be effectively used as a means to assess reservoir characteristics in a one-well test. The test program resulted in a unique data set which shows promise as a means to improve understanding of the reservoir characteristics. In December 1982, an RFP was issued to obtain an industrial partner to obtain follow-on data on the injection/backflow technique in a second field, and to study any alternate advanced concepts for injection testing which the industrial community might recommend. The East Mesa Geothermal Field was selected for the second test series. Two wells were utilized for testing, and a series of ten tests were conducted in July and August 1983, aimed principally at further evaluation of the injection/backflow technique.

  12. Precision of the reportable result. Simultaneous optimisation of number of preparations and injections for sample and reference standard in quantitative liquid chromatography.

    PubMed

    Ermer, J; Agut, C

    2014-08-01

    In pharmaceutical analysis, the precision of the reportable result, i.e. the result which is to be compared to the specification limit, is relevant for the evaluation of the suitability of the analytical procedure. But also for other applications, the precision of the result is important and an optimisation often of interest. However, increasing the number of determinations (e.g. injections or preparations) will reduce only the variability (or standard error) of the corresponding precision level. Therefore, the knowledge of the individual variance contributions, obtained from reliable precision studies is important to determine on a scientific basis which format of the (reportable) result, i.e. the number of injections and sample preparations (or even series), should be used. In case of relative analytical procedures such as LC, the calibration model and format, i.e. the number of determinations of the reference standard is one of the factors (besides instrument, operator, reagents, etc.) affecting the between-series variance contribution at intermediate precision/reproducibility level. Consequently, the precision of the reportable result is only valid for the calibration format used to obtain intermediate precision/reproducibility. Instead of repeating the whole precision study to optimize the calibration format, the present paper describes a statistical approach using variability results from the original precision study.

  13. Automated sample preparation based on the sequential injection principle. Solid-phase extraction on a molecularly imprinted polymer coupled on-line to high-performance liquid chromatography.

    PubMed

    Theodoridis, Georgios; Zacharis, Constantinos K; Tzanavaras, Paraskevas D; Themelis, Demetrius G; Economou, Anastasios

    2004-03-19

    A molecularly imprinted polymer (MIP) prepared using caffeine, as a template, was validated as a selective sorbent for solid-phase extraction (SPE), within an automated on-line sample preparation method. The polymer produced was packed in a polypropylene cartridge, which was incorporated in a flow system prior to the HPLC analytical instrumentation. The principle of sequential injection was utilised for a rapid automated and efficient SPE procedure on the MIP. Samples, buffers, washing and elution solvents were introduced to the extraction cartridge via a peristaltic pump and a multi-position valve, both controlled by appropriate software developed in-house. The method was optimised in terms of flow rates, extraction time and volume. After extraction, the final eluent from the extraction cartridge was directed to the injection loop and was subsequently analysed on HPLC. The overall set-up facilitated unattended operation, operation and improved both mixing fluidics and method development flexibility. This system may be readily built in the laboratory and can be further used as an automated platform for on-line sample preparation.

  14. INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Two-stage liquid phase epitaxy for fabrication of buried InGaAsP/InP heterostructures

    NASA Astrophysics Data System (ADS)

    Procházková, O.; Novotný, J.; Šrobár, F.

    1988-11-01

    The technology of growth of buried heterojunction lasers emitting at 1.3 μm and some of their physical properties are described. Mesa stripes 8-μm wide were formed on heteroepitaxial wafers grown by liquid phase epitaxy at 630°C. They were buried by a second process at a lower temperature (590°C). The threshold current was about 100 mA and the temperature sensitivity was characterized by a parameter amounting to about 60 K. Single-mode lasing was observed occasionally.

  15. Comparing solid phase extraction and direct injection for the analysis of ultra-trace levels of relevant explosives in lake water and tributaries using liquid chromatography-electrospray tandem mass spectrometry.

    PubMed

    Ochsenbein, Ueli; Zeh, Markus; Berset, Jean-Daniel

    2008-06-01

    Off-line solid phase extraction and direct injection analysis were evaluated for the determination of traces of explosives such as TNT and its mono and diamino metabolites, HMX, RDX, nitroglycerin and PETN in lake water and tributaries applying liquid chromatography-electrospray tandem mass spectrometry. Improved chromatographic separation was achieved on a phenyl based stationary phase with baseline resolution of the mono- and diamino metabolites of TNT. Identification and quantification of the target compounds was performed by multiple reaction monitoring applying electrospray ionization in either the positive mode for the diaminometabolites of TNT or the negative mode for all other compounds. An extensive method validation was performed and limits of quantification were obtained for the explosives in preconcentrated lake water samples from 0.03 to 1 ng l(-1) and 0.1 to 5 ng l(-1) in river water. Direct injection analysis revealed comparable results to preconcentrated water samples for the most persistent explosives. Analysis of lake water samples collected at different depths showed the presence of HMX, RDX and PETN at concentrations from 0.1 to 0.4 ng l(-1). The analysis of main tributaries revealed concentrations from 0.1 to 0.9 ng l(-1) of the same compounds. They seem to be responsible for the contamination of the explosives in the lakes.

  16. Development of an ultra fast liquid chromatography-tandem mass spectrometry method for simultaneous determination of cefazedone and etimicin in beagle dog plasma: Application to the pharmacokinetic study of the combination of cefazedone and etimicin injections.

    PubMed

    Cui, Yan; Ma, Ning; Li, Xiaoyan; Lv, Chunxiao; Li, Mingjie; Li, Minghua; Song, Liangwei; Liu, Mingxia; Li, Qing; Bi, Kaishun

    2014-10-23

    A new, sensitive and efficient ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed and validated for simultaneous quantification of cefazedone and etimicin in beagle dog plasma. After addition of the internal standard (IS) metronidazole, plasma samples were treated by protein precipitation procedure, and then separated on a Venusil MP C18 column (100mm×2.1mm, 3.0μm) (Venusil, China) using gradient elution with the mobile phase consisting of 0.01% heptafluorobutyric acid (HFBA) in acetonitrile and 0.01% HFBA in water at a flow rate of 0.4mLmin(-1). The detection of the analytes was performed on 4000Q UFLC-MS/MS system with turbo ion spray source in the positive ion and multiple reaction-monitoring (MRM) mode. The linear range was 1.0-200μgmL(-1) for cefazedone and 0.5-100μgmL(-1) for etimicin, with lower limits of quantification of 1.0 and 0.5μgmL(-1), respectively. Intra-day and inter-day precisions were within 7.2% and 4.3%, respectively for both analytes, and the accuracy (relative error, RE, %) was less than 10.7% and 12.7%, respectively. The mean absolute extraction recoveries of analytes and IS from beagle dog plasma were all more than 73.22%. The validated method was successfully applied to the pharmacokinetic study of cefazedone and etimicin in beagle dog after intravenous administration of cefazedone injection combined with etimicin injection and the two single injections alone, respectively. The results indicated there were not obvious differences between the pharmacokinetic behaviors between the combined group and either of the single groups.

  17. Plasmon resonance energy transfer and hot electron injection induced high photocurrent density in liquid junction Ag@Ag2S sensitized solar cells.

    PubMed

    Wu, Dapeng; Wang, Fujuan; Wang, Hongju; Cao, Kun; Gao, Zhiyong; Xu, Fang; Jiang, Kai

    2016-10-18

    An in situ technique was developed to deposit Ag@Ag2S core-shell quantum dots on a SnO2 mesoporous film for solar energy conversion. When adopted as a photoanode, an impressive high photocurrent density of ∼25.6 mA cm(-2) was demonstrated in a cell configuration using polysulfide S(2-)/Sn(2-) as an electrolyte and Cu2S/brass as a counter electrode, which leads to a power conversion efficiency of ∼0.784% for this environmentally benign device. Optical measurements showed that Ag nanoparticles could be employed as plasmon resonance centers to enhance the harvesting efficiency of incident light at the visible and near-infrared range. Moreover, photoluminescence spectra demonstrated fast charge transfer at Ag@Ag2S/SnO2 interfaces, which facilitates direct hot electron injection from sensitizers to the SnO2 matrix and finally gives rise to the high photocurrent density.

  18. A novel actuation technique for the on-demand injection of charge-free conducting droplets in a viscous dielectric liquid

    NASA Astrophysics Data System (ADS)

    Raisin, Jonathan; Atten, Pierre; Reboud, Jean-Luc

    2013-03-01

    The paper presents recent improvements and results on the on-demand injection of small electrically neutral water drops in oil by high electric field pulses. The technique consists in applying a voltage pulse promoting the deformation of a water meniscus at the end of a capillary tube through the action of electric forces. For pulses of calibrated energy, the transient deformation can lead to the inertia-based ejection of a small uncharged droplet. Application of in-house developed multi-stage electric pulses offers, in contrast to usual single pulses, wider ranges of droplet size, improved reproducibility and stable ejection trajectories. Influence of the main parameters on the extracted droplet diameter is presented: it is shown that, by using capillary tubes of outer tip diameter close to 0.5 mm, it is possible to obtain, in a reproducible way, drops of diameter ranging from less than 15 μm up to more than 250 μm.

  19. Application of dynamic liquid-phase microextraction and injection port derivatization combined with gas chromatography-mass spectrometry to the determination of acidic pharmaceutically active compounds in water samples.

    PubMed

    Zhang, Jie; Lee, Hian Kee

    2009-10-30

    A method has been established for the determination of four pharmaceutically active compounds (ibuprofen, ketoprofen, naproxen and clofibric acid) in water samples using dynamic hollow fiber liquid-phase microextraction (HF/LPME) followed by gas chromatography (GC) injection port derivatization and GC-mass spectrometric (MS) determination. Dynamic HF/LPME is a novel approach to microextraction that involves the use of a programmable syringe pump to move the liquid phases participating in the extraction so as to facilitate the process. Trimethylanilinium hydroxide (TMAH) was used as derivatization reagent for the analytes to increase their volatility and improve chromatographic separation. Parameters that affect extraction efficiency (selection of organic solvent, volume of organic solvent, agitation in the donor phase, plunger movement and extraction time) were investigated. Under optimal conditions, the proposed method provided good enrichment factors up to 251, reproducibility ranging from 3.26% to 10.61%, and good linearity from 0.2 to 50 microg/L. The limits of detection ranged between 0.01 and 0.05 microg/L (S/N=3) using selective ion monitoring. This method was applied to the determination of the four pharmaceutically active compounds in tap water and wastewater collected from a drain in the vicinity of a hospital.

  20. "Dilute-and-inject" multi-target screening assay for highly polar doping agents using hydrophilic interaction liquid chromatography high resolution/high accuracy mass spectrometry for sports drug testing.

    PubMed

    Görgens, Christian; Guddat, Sven; Orlovius, Anne-Katrin; Sigmund, Gerd; Thomas, Andreas; Thevis, Mario; Schänzer, Wilhelm

    2015-07-01

    In the field of LC-MS, reversed phase liquid chromatography is the predominant method of choice for the separation of prohibited substances from various classes in sports drug testing. However, highly polar and charged compounds still represent a challenging task in liquid chromatography due to their difficult chromatographic behavior using reversed phase materials. A very promising approach for the separation of hydrophilic compounds is hydrophilic interaction liquid chromatography (HILIC). Despite its great potential and versatile advantages for the separation of highly polar compounds, HILIC is up to now not very common in doping analysis, although most manufacturers offer a variety of HILIC columns in their portfolio. In this study, a novel multi-target approach based on HILIC high resolution/high accuracy mass spectrometry is presented to screen for various polar stimulants, stimulant sulfo-conjugates, glycerol, AICAR, ethyl glucuronide, morphine-3-glucuronide, and myo-inositol trispyrophosphate after direct injection of diluted urine specimens. The usage of an effective online sample cleanup and a zwitterionic HILIC analytical column in combination with a new generation Hybrid Quadrupol-Orbitrap® mass spectrometer enabled the detection of highly polar analytes without any time-consuming hydrolysis or further purification steps, far below the required detection limits. The methodology was fully validated for qualitative and quantitative (AICAR, glycerol) purposes considering the parameters specificity; robustness (rRT < 2.0%); linearity (R > 0.99); intra- and inter-day precision at low, medium, and high concentration levels (CV < 20%); limit of detection (stimulants and stimulant sulfo-conjugates < 10 ng/mL; norfenefrine; octopamine < 30 ng/mL; AICAR < 10 ng/mL; glycerol 100 μg/mL; ETG < 100 ng/mL); accuracy (AICAR 103.8-105.5%, glycerol 85.1-98.3% at three concentration levels) and ion suppression/enhancement effects.

  1. INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Liquid phase epitaxial growth of GaInAsP/InP laser structures

    NASA Astrophysics Data System (ADS)

    Nohavica, D.; Têminová, J.; Berková, D.; Zagrádková, M.; Kortan, I.; Zelinka, I.; Walachová, I.; Malina, V.

    1988-11-01

    A modified single-phase liquid phase epitaxy method was developed on the basis of a novel variant of the growth boat. The method was used to grow GaInAsP/InP double heterostructures for lasers emitting at 1.3 and 1.55 μm. The main properties of wide-contact diodes (radiation power and threshold current density) were adopted as the characteristics of the quality of heterostructures characterized by different configurations of active and guiding layers. The quality of the structure was confirmed by the fabrication of laser diodes of the following types: stripe with oxide insulation, clad-ridge waveguide, and double-channel planar buried.

  2. Flow-injection spectrophotometric determination of bromate in bottled drinking water samples using chlorpromazine reagent and a liquid waveguide capillary cell.

    PubMed

    Tóth, Ildikó V; Santos, Inês C; Azevedo, Cláudia F M; Fernandes, Jorge F S; Páscoa, Ricardo N M J; Mesquita, Raquel B R; Rangel, António O S S

    2013-01-01

    In this work, aiming to develop a simple, inexpensive method for the determination of low bromate levels in water samples, a liquid waveguide capillary cell (LWCC) was coupled to a FIA system. The long optical path (100 cm) of the LWCC was used to improve the sensitivity and the limit of detection without resorting to any off-line or in-line preconcentration processes. The spectrophotometric determination was based on the oxidation of chlorpromazine by bromate in an acidic medium, resulting in the formation of a colored radical product. Sulfamic acid was added to the reagent for minimizing the interference of nitrite, and a chelating ion exchange resin was used to remove major cationic interferences. The developed system allowed the determination of bromate within the range between 1 - 20 μg L(-1) with a detection limit of 0.2 μg L(-1).

  3. Injectable barriers for waste isolation

    SciTech Connect

    Persoff, P.; Finsterle, S.; Moridis, G.J.; Apps, J.; Pruess, K.; Muller, S.J.

    1995-03-01

    In this paper the authors report laboratory work and numerical simulation done in support of development and demonstration of injectable barriers formed from either of two fluids: colloidal silica or polysiloxane. Two principal problems addressed here are control of gel time and control of plume emplacement in the vadose zone. Gel time must be controlled so that the viscosity of the barrier fluid remains low long enough to inject the barrier, but increases soon enough to gel the barrier in place. During injection, the viscosity must be low enough to avoid high injection pressures which could uplift or fracture the formation. To test the grout gel time in the soil, the injection pressure was monitored as grouts were injected into sandpacks. When grout is injected into the vadose zone, it slumps under the influence of gravity, and redistributes due to capillary forces as it gels. The authors have developed a new module for the reservoir simulator TOUGH2 to model grout injection into the vadose zone, taking into account the increase of liquid viscosity as a function of gel concentration and time. They have also developed a model to calculate soil properties after complete solidification of the grout. The numerical model has been used to design and analyze laboratory experiments and field pilot tests. The authors present the results of computer simulations of grout injection, redistribution, and solidification.

  4. Fuel injection device

    SciTech Connect

    Ohmori, T.; Nakatsuka, H.; Kanou, H.

    1987-03-31

    A fuel injection device is described for injecting fuel into a combustion chamber of an internal combustion engine, comprising: a body having first and second bores formed therein and extending in the axial direction thereof; a delivering plunger fitted into the first bore and defining a delivering pump chamber therein; driving means for reciprocating the delivering plunger in synchronism to the engine; pressurized medium supplying means for supplying a pressurized medium under a constant pressure to the delivering pump chamber, the pressurized medium supplying means including a pressurized medium source and a control passage linking the pressurized medium source to the delivering pump chamber; an electromagnetic valve provided on the control passage for opening and closing the control passage; and an injection plunger fitted into the second bore and defining, in the second bore, a linking chamber communicating with the delivering pump chamber and an injection pump chamber, the linking chamber and the delivering chamber becoming a liquid-tight chamber when the electromagnetic valve closes the control passage.

  5. Pegaptanib Injection

    MedlinePlus

    ... if you have or have ever had diabetes, high blood pressure, a heart attack, or a stroke.tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while using pegaptanib injection, ...

  6. Ramucirumab Injection

    MedlinePlus

    ... doctor if you have or have ever had high blood pressure, a wound that has not healed, or liver disease.tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Ramucirumab injection may harm your unborn baby. You ...

  7. Reslizumab Injection

    MedlinePlus

    ... the infusion or for a short period of time after the infusion has finished.You will receive each injection of reslizumab in a doctor's office or medical facility. You will stay in the office for some time after you receive the medication so your doctor ...

  8. Dexrazoxane Injection

    MedlinePlus

    ... are used to treat or prevent certain side effects that may be caused by chemotherapy medications. Dexrazoxane ... Dexrazoxane injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: pain or swelling in the place ...

  9. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    NASA Technical Reports Server (NTRS)

    Singh, R.; Sinha, S.; Hsu, N. J.; Thakur, R. P. S.; Chou, P.; Kumar, A.; Narayan, J.

    1990-01-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid semiconductors/superconductors transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray defraction, electron microscopy, and energy dispersive x-ray analysis are discussed.

  10. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    NASA Astrophysics Data System (ADS)

    Singh, R.; Sinha, S.; Hsu, N. J.; Thakur, R. P. S.; Chou, P.; Kumar, A.; Narayan, J.

    1990-04-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid semiconductors/superconductors transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray defraction, electron microscopy, and energy dispersive x-ray analysis are discussed.

  11. In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

    NASA Technical Reports Server (NTRS)

    Singh, R.; Sinha, S.; Hsu, N. J.; Thakur, R. P. S.; Chou, P.; Kumar, A.; Narayan, J.

    1991-01-01

    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectrics having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writing capability, complex device structures like three terminal hybrid semiconductor/superconductor transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray deffraction, electron microscopy, and energy dispersive x-ray analysis are discussed.

  12. The anti-surfactant effect of silane on the facets-controlled growth of GaN nanorods by MOCVD

    NASA Astrophysics Data System (ADS)

    Li, J. Z.; Chen, Z. Z.; Li, S. F.; Jiao, Q. Q.; Feng, Y. L.; Jiang, S. X.; Chen, Y. F.; Yu, T. J.; Shen, B.; Zhang, G. Y.

    2016-08-01

    N-polar GaN nanorods were selective area grown by continuous mode metalorganic chemical vapor deposition (MOCVD) under a Ga-rich and high silane flow condition. The interruption comparing with continuous supply of silane flow was performed to study the role of silane flux. High resolution scanning electron microscopy (SEM), x-ray diffraction (XRD), cathodoluminescence (CL) and x-ray photoelectron spectroscopy (XPS) measurements were performed. The enhanced vertical growth rate was achieved as 42 μm/h and sharp smooth m-plane, r-plane and c-plane facets were obtained for the nanorods with high silane flux. Sisbnd N bonds were clarified to be formed on the surface of the nanorod by XPS spectra. The silane acting as anti-surfactant was suggested to explain the diffusion and incorporation of the species on the facets of GaN nanorods.

  13. Species transport and chemical reaction in a MOCVD reactor and their influence on the GaN growth uniformity

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi; Fang, Haisheng; Yao, Qingxia; Yan, Han; Gan, Zhiyin

    2016-11-01

    Fluid flow, heat transfer, and species transport with chemical reactions have been investigated for gallium nitride (GaN) growth in a commercial metal-organic chemical vapor deposition (MOCVD) reactor. Both the growth rate and the growth uniformity are investigated zone by zone, as the wafers are divided into three zones/groups according to their distances to the susceptor center. The results show that species transport in the reactor is affected by the inlet conditions, i.e., the premixed or non-premixed inlet, the inlet temperature, the total gas flow rate, and the V/III component ratio, and reveal that the premixed inlet condition is preferred for uniform growth. Especially, a large total flow rate or a low V/III ratio results in both increase of the growth rate and improvement of the growth uniformity.

  14. DLTS and MCTS analysis of the influence of growth pressure on trap generation in MOCVD GaN

    NASA Astrophysics Data System (ADS)

    Shah, P. B.; Dedhia, R. H.; Tompkins, R. P.; Viveiros, E. A.; Jones, K. A.

    2012-12-01

    We demonstrate with DLTS and MCTS how changing growth pressure during MOCVD growth of GaN affects the majority and minority carrier trap signatures. Results indicate which specific traps are most strongly connected with the increased carbon concentration that lower growth pressure has led to. Carbon concentration is also verified with SIMS measurements. DLTS and MCTS measurements, related to carrier thermalization from traps, made up to a temperature of 450 K have found four majority carrier and two minority carrier traps. Using a lower growth pressures, at which greater incorporation of carbon is possible, has lead to larger concentrations of most of the traps; just as others have observed. However, the trap at EC - 0.48 eV is the least affected by the growth pressure. We relate all the traps found from DLTS and MCTS to those identified by others and mention the constituent atoms that the research community identifies with these traps.

  15. Resistive switching phenomena of HfO2 films grown by MOCVD for resistive switching memory devices

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Dong; Yun, Min Ju; Kim, Sungho

    2016-08-01

    The resistive switching phenomena of HfO2 films grown by using metal organic chemical vapor deposition (MOCVD) was studied for the application of resistive random access memory (ReRAM) devices. In the fabricated Pt/HfO2/TiN memory cells, bipolar resistive switching characteristics were observed, and the set and reset states were measured to be as low as 7 μA and 4 μA, respectively, at V READ = 1 V. Regarding the resistive switching performance, stable resistive switching (RS) performance was observed under 40 repetitive dc cycles with small variations of set/reset voltages and the currents and good retention characteristics of over 105 s in both the low-resistance state (LRS) and the high-resistance state (HRS). These results show the possibility of using MOCVDgrown HfO2 films as a promising resistive switching materials for ReRAM applications.

  16. Initial stages of TiO 2 thin films MOCVD growth studied by in situ surface analyses

    NASA Astrophysics Data System (ADS)

    Brevet, A.; Peterlé, P. M.; Imhoff, L.; Marco de Lucas, M. C.; Bourgeois, S.

    2005-02-01

    In situ chemical surface analyses using X-ray photoelectron spectroscopy (XPS) were performed to understand the initial stages of TiO 2 thin-film MOCVD growth. Deposits on Si (1 0 0), a few nanometres thick, were obtained at a fixed temperature of 650 °C and for two different pressures, 2.9 and 0.05 mbar, using titanium tetraisopropoxide (TTIP) as precursor. Pressure lowering led to a higher deposit growth rate. Reduction of titanium with respect to stoichiometric titanium dioxide and oxidation of the wet-cleaned silicon substrate are observed from decomposition of the Ti 2p and Si 2p peaks. The formation of a TiSi xO y mixed oxide is also pointed out and confirmed by the presence of a characteristic component in the O 1 s peak.

  17. Driving Down HB-LED Costs. Implementation of Process Simulation Tools and Temperature Control Methods of High Yield MOCVD Growth

    SciTech Connect

    Quinn, William

    2012-04-30

    The overall objective of this multi-faceted program is to develop epitaxial growth systems that meet a goal of 75% (4X) cost reduction in the epitaxy phase of HB-LED manufacture. A 75% reduction in yielded epitaxy cost is necessary in order to achieve the cost goals for widespread penetration of HB-LED's into back-lighting units (BLU) for LCD panels and ultimately for solid-state lighting (SSL). To do this, the program will address significant improvements in overall equipment Cost of Ownership, or CoO. CoO is a model that includes all costs associated with the epitaxy portion of production. These aspects include cost of yield, capital cost, operational costs, and maintenance costs. We divide the program into three phases where later phases will incorporate the gains of prior phases. Phase one activities are enabling technologies. In collaboration with Sandia National Laboratories we develop a Fluent-compatible chemistry predictive model and a set of mid-infrared and near-ultraviolet pyrometer monitoring tools. Where previously the modeling of the reactor dynamics were studied within FLUENT alone, here, FLUENT and Chemkin are integrated into a comprehensive model of fluid dynamics and the most advanced transport equations developed for Chemkin. Specifically, the Chemkin model offered the key reaction terms for gas-phase nucleation, a key consideration in the optimization of the MOCVD process. This new predictive model is used to design new MOCVD reactors with optimized growth conditions and the newly developed pyrometers are used monitor and control the MOCVD process temperature to within 0.5°C run-to-run and within each wafer. This portion of the grant is in collaboration with partners at Sandia National Laboratories. Phase two activities are continuous improvement projects which extend the current reactor platform along the lines of improved operational efficiency, improved systems control for throughput, and carrier modifications for increased yield

  18. In situ pre-growth calibration using reflectance as a control strategy for MOCVD fabrication of device structures

    SciTech Connect

    Breiland, W.G.; Hou, H.Q.; Chui, H.C.; Hammons, B.E.

    1996-08-01

    In situ normal incidence reflectance, combined with a virtual interface model, is being used routinely on a commercial MOCVD reactor to measure growth rates of compound semiconductor films. The technique serves as a pre-growth calibration tool analogous to the use of RHEED in MBE as well as a real-time monitor throughout the run. An application of the method to the growth of a vertical cavity surface emitting laser (VCSEL) device structure is presented. All necessary calibration information can be obtained using a single run lasting less than one hour. Working VCSEL devices are obtained on the first try after calibration. Repeated runs have yielded {+-} 0.3% reproducibility of the Fabry-Perot cavity wavelength over the course of more than 100 runs.

  19. Effect of 100 MeV Ni9+ ion irradiation on MOCVD grown n-GaN

    NASA Astrophysics Data System (ADS)

    Suresh Kumar, V.; Kumar, J.; Puviarasu, P.; Munawar Basha, S.; Kanjilal, D.; Asokan, K.

    2011-11-01

    Metal-organic chemical vapor deposition (MOCVD) grown n-type Gallium nitride (GaN) has been irradiated with 100 MeV Ni9+ ions at room temperature. Atomic force microscopy (AFM) images show the nano-clusters' formation upon irradiation and the irradiated GaN surface roughness increases with the increasing ion fluences. High-resolution X-ray diffraction (HR-XRD) analysis reveals the formation of Ga2O3 due to the interface mixing of GaN/Al2O3 upon irradiation. FWHM values of GaN (0 0 0 2) increases due to the lattice disorder. Photoluminescence studies show reduced band edge emission and yellow luminescence (YL) intensity with the increasing ion fluences. Change in the band gap energy between 3.38 and 3.04 eV was measured by UV-visible optical absorption spectrum on increasing the ion fluences.

  20. Controlled low Si doping and high breakdown voltages in GaN on sapphire grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Agarwal, Anchal; Gupta, Chirag; Enatsu, Yuuki; Keller, Stacia; Mishra, Umesh

    2016-12-01

    Controlled n-type doping down to 2 × 1015 cm-3 was achieved in GaN grown on sapphire by MOCVD by balancing the n-type Si doping with respect to the background carbon and oxygen levels. A dopant level of ˜1 × 1016 cm-3 displayed a very high mobility of 899 cm2 V-1 s-1. High electron mobility in the drift layer leads to a low on resistance and high current densities without compromising on any other properties of the device. Schottky diodes processed on these low n-type layers showed low R on values, while the p-n diodes display high reverse breakdown voltages in excess of 1000 V for 8 μm thick drift layers with a doping of 2 × 1015 cm-3.

  1. A simple strategy for determining ethanol in all types of alcoholic beverages based on its on-line liquid-liquid extraction with chloroform, using a flow injection system and Fourier transform infrared spectrometric detection in the mid-IR.

    PubMed

    Gallignani, Máximo; Ayala, Carlos; Brunetto, Maria Del Rosario; Burguera, Jose Luis; Burguera, Marcela

    2005-12-15

    In this work, a simple strategy for the determination of ethanol in all types of alcoholic beverages using Fourier transform infrared spectrometric detection has been developed. The methodological proposal includes the quantitative on-line liquid-liquid extraction of ethanol with chloroform, through a sandwich type cell equipped with a PTFE membrane, using a two-channel manifold; and direct measurement of the analyte in the organic phase, by means of Fourier transform infrared spectrometry. The quantification was carried out measuring the ethanol absorbance at 877cm(-1)(,) corrected by means of a baseline established between 844 and 929cm(-1). The procedure, which does not require any sample pretreatment (except for the simple degassing of beer and gassy wine samples, and a simple dilution of spirits with water), was applied to determine ethanol in different alcoholic beverages such as beers, wines and spirits. The results obtained highly agree with those obtained by a derivative FTIR spectrometric procedure, and by head space-gas chromatography with FID detection. The proposed method is simple, fast, precise and accurate. Moreover, it can be easily adapted to any infrared spectrometer equipped with a standard transmission IR cell, and provides attractive analytical features, which are comparable to, or better than those offered by other published methods. In consequence, it represents a valid alternative for the determination of ethanol in alcoholic beverages, and could be suitable for the routine control analysis.

  2. An alternative approach for assessment of liquid chromatography-mass spectrometry matrix effects using auto-sampler programmed co-injection.

    PubMed

    Rogers, Caitlyn A; Stockham, Peter C; Nash, Christine M; Martin, Sheridan M; Kostakis, Chris; Lenehan, Claire E

    2016-03-01

    We report the use of auto-sampler programmable functions to co-inject analyte standard solution and matrix extract to assess ion enhancement and suppression (matrix effects) in LC-MS. This is effectively an automated post-extraction addition (APEA) procedure, emulating the manual post-extraction addition (PEA) approach widely adopted for assessment of matrix effects. To verify that APEA was comparable to the conventional PEA approach, matrix effects were determined using both methods for a selection of 31 illicit and pharmaceutical drugs in 10 different human urine extracts. Matrix effects measured using APEA were statistically indistinguishable from manual PEA methodology for 27 of the 31 drugs. Of the four drugs that showed significant differences using the two methods, three differed by less than 2 %, which is within the expected accuracy limits required for matrix effect determinations. The remaining analyte, trimeprazine, was found to degrade in the spiked PEA matrix extract, accounting for the difference between matrix effects measured by the PEA and APEA approaches. APEA enables a single matrix extract to be assessed at multiple analyte concentrations, resulting in a considerable reduction in sample preparation time. In addition, APEA can reduce the quantity of analyte-free sample matrix required for matrix effect assessment, which is an important consideration in certain analytical and bioanalytical fields. This work shows that APEA may be considered as an acceptable alternative to PEA for the assessment of matrix effects in LC-MS method validation and may be applicable to a variety of matrices such as environmental samples.

  3. Pressurized feed-injection spray-forming apparatus

    DOEpatents

    Berry, Ray A.; Fincke, James R.; McHugh, Kevin M.

    1995-01-01

    A spray apparatus and method for injecting a heated, pressurized liquid in a first predetermined direction into a pressurized gas flow that is flowing in a second predetermined direction, to provide for atomizing and admixing the liquid with the gas to form a two-phase mixture. A valve is also disposed within the injected liquid conduit to provide for a pulsed injection of the liquid and timed deposit of the atomized gas phase. Preferred embodiments include multiple liquid feed ports and reservoirs to provide for multiphase mixtures of metals, ceramics, and polymers.

  4. Determination of endocrine disrupting chemicals and antiretroviral compounds in surface water: A disposable sorptive sampler with comprehensive gas chromatography - Time-of-flight mass spectrometry and large volume injection with ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Wooding, Madelien; Rohwer, Egmont R; Naudé, Yvette

    2017-05-05

    Many rural dwellers and inhabitants of informal settlements in South Africa are without access to treated water and collect untreated water from rivers and dams for personal use. Endocrine disrupting chemicals (EDCs) have been detected in surface water and wildlife of South Africa. EDCs are often present in complex environmental matrices at ultra-trace levels complicating detection thereof. We report a simplified multi-residue approach for the detection and quantification of EDCs, emerging EDCs, and antiretroviral drugs in surface water. A low cost (less than one US dollar), disposable, sorptive extraction sampler was prepared in-house. The disposable samplers consisted of polydimethylsiloxane (PDMS) tubing fashioned into a loop which was then placed in water samples to concentrate EDCs and emerging pollutants. The PDMS samplers were thermally desorbed directly in the inlet of a GC, thereby eliminating the need for expensive consumable cryogenics. Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) was used for compound separation and identification. Linear retention indices of EDCs and emerging pollutants were determined on a proprietary Crossbond(®) phase Rtx(®)-CLPesticides II GC capillary column. In addition, large volume injection of surface water into an ultra-performance liquid chromatograph tandem mass spectrometer (UPLC-MS/MS) was used as complementary methodology for the detection of less volatile compounds. Large volume injection reduced tedious and costly sample preparation steps. Limits of detection for the GC method ranged from 1 to 98pg/l and for the LC method from 2 to 135ng/l. Known and emerging EDCs such as pharmaceuticals, personal care products and pesticides, as well as the antiretroviral compounds, efavirenz and nevirapine, were detected in surface water from South Africa at concentration levels ranging from 0.16ng/l to 227ng/l.

  5. Method development and application of offline two-dimensional liquid chromatography/quadrupole time-of-flight mass spectrometry-fast data directed analysis for comprehensive characterization of the saponins from Xueshuantong Injection.

    PubMed

    Yang, Wenzhi; Zhang, Jingxian; Yao, Changliang; Qiu, Shi; Chen, Ming; Pan, Huiqin; Shi, Xiaojian; Wu, Wanying; Guo, Dean

    2016-09-05

    Xueshuantong Injection (XSTI), derived from Notoginseng total saponins, is a popular traditional Chinese medicine injection for the treatment of thrombus-resultant diseases. Current knowledge on its therapeutic basis is limited to five major saponins, whereas those minor ones are rarely investigated. We herein develop an offline two-dimensional liquid chromatography/quadrupole time-of-flight mass spectrometry-fast data directed analysis (offline 2D LC/QTOF-Fast DDA) approach to systematically characterize the saponins contained in XSTI. Key parameters affecting chromatographic separation in 2D LC (including stationary phase, mobile phase, column temperature, and gradient elution program) and the detection by QTOF MS (involving spray voltage, cone voltage, and ramp collision energy) were optimized in sequence. The configured offline 2D LC system showed an orthogonality of 0.84 and a theoretical peak capacity of 8976. Total saponins in XSTI were fractionated into eleven samples by the first-dimensional hydrophilic interaction chromatography, which were further analyzed by reversed-phase UHPLC/QTOF-Fast DDA in negative ion mode. The fragmentation features evidenced from 36 saponin reference standards, high-accuracy MS and Fast-DDA-MS(2) data, elemental composition (C<80, H<120, O<50), double-bond equivalent (DBE 5-15), and searching an in-house library of Panax notoginseng, were simultaneously utilized for structural elucidation. Ultimately, 148 saponins were separated and characterized, and 80 have not been isolated from P. notoginseng. An in-depth depiction of the chemical composition of XSTI was achieved. The results obtained would benefit better understanding of the therapeutic basis and significant promotion on the quality standard of XSTI as well as other homologous products.

  6. Magnetic detection of ferrofluid injection zones

    SciTech Connect

    Borglin, S.; Moridis, G.; Becker, A.

    1998-03-01

    Ferrofluids are stable colloidal suspensions of magnetic particles that can be stabilized in various carrier liquids. In this study the authors investigate the potential of ferrofluids to trace the movement and position of liquids injected in the subsurface using geophysical methods. An ability to track and monitor the movement and position of injected liquids is essential in assessing the effectiveness of the delivery system and the success of the process. Ferrofluids can also provide a significant detection and verification tool in containment technologies, where they can be injected with the barrier liquids to provide a strong signature allowing determination of the barrier geometry, extent, continuity and integrity. Finally, ferrofluids may have unique properties as tracers for detecting preferential flow features (such as fractures) in the subsurface, and thus allow the design of more effective remediation systems. In this report the authors review the results of the investigation of the potential of ferrofluids to trace the movement and position of liquids injected in the subsurface using geophysical methods. They demonstrate the feasibility of using conventional magnetometry for detecting subsurface zones of injected ferrofluids used to trace liquids injected for remediation or barrier formation. The geometrical shapes considered were a sphere, a thin disk, a rectangular horizontal slab, and a cylinder. Simple calculations based on the principles of magnetometry are made to determine the detection depths of FTs. Experiments involving spherical, cylindrical and horizontal slabs show a very good agreement between predictions and measurements.

  7. Fast heating induced impulse halogenation of refractory sample components in electrothermal atomic absorption spectrometry by direct injection of a liquid halogenating agent.

    PubMed

    György, Krisztina; Ajtony, Zsolt; Van Meel, Katleen; Van Grieken, René; Czitrovszky, Aladár; Bencs, László

    2011-09-15

    A novel electrothermal atomic absorption spectrometry (ETAAS) method was developed for the halogenation of refractory sample components (Er, Nd and Nb) of lithium niobate (LiNbO(3)) and bismuth tellurite (Bi(2)TeO(5)) optical single crystals to overcome memory effects and carry-over. For this purpose, the cleaning step of a regular graphite furnace heating program was replaced with a halogenation cycle. In this cycle, after the graphite tube cooled to room temperature, a 20 μL aliquot of liquid carbon tetrachloride (CCl(4)) was dispensed with a conventional autosampler into the graphite tube. The CCl(4) was partially dried at 80°C under the mini-flow (40 cm(3) min(-1)) condition of the Ar internal furnace gas (IFG), then the residue was decomposed (pyrolyzed) by fast furnace heating at 1900-2100°C under interrupted flow of the IFG. This step was followed by a clean-out stage at 2100°C under the maximum flow of the IFG. The advantage of the present method is that it does not require any alteration to the graphite furnace gas supply system in contrast to most of the formerly introduced halogenation techniques. The effectiveness of the halogenation method was verified with the determination of Er and Nd dopants in the optical crystals. In these analyses, a sensitivity decrease was observed, which was likely due to the enhanced deterioration of the graphite tube surface. Therefore, the application of mathematical correction (resloping) of the calibration was also required. The calibration curves were linear up to 1.5 and 10 μmol L(-1) for Er and Nd, respectively. Characteristic masses of 18 and 241 pg and the limit of detection (LOD) values of 0.017 and 0.27 μmol L(-1) were found for Er and Nd, respectively. These LOD data correspond to 0.68 μmol mol(-1) Er and 11 μmol mol(-1) Nd in solid bismuth tellurite samples. The analytical results were compared with those obtained by a conventional ETAAS method and validated with X-ray fluorescence spectrometry analysis.

  8. A prototype space flight intravenous injection system

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.

    1985-01-01

    Medical emergencies, especially those resulting from accidents, frequently require the administration of intravenous fluids to replace lost body liquids. The development of a prototype space flight intravenous injection system is presented. The definition of requirements, injectable concentrates development, water polisher, reconstitution hardware development, administration hardware development, and prototype fabrication and testing are discussed.

  9. Lung embolism with liquid silicone.

    PubMed

    Rodríguez, M A; Martínez, M C; Lopez-Artíguez, M; Soria, M L; Bernier, F; Repetto, M

    1989-03-01

    A lung embolism was reported in a case involving death following repeated injections of liquid silicone for aesthetic reasons. The liquid extracted from the sites of injection was identified as methylsilicone using infrared spectrophotometry, and the presence of silicone in vacuoles in the lung was verified by scanning electron microscopy with energy dispersive X-ray analysis (EDXA). A study has been carried out with rats after intravenous and subcutaneous injections of methylsilicone.

  10. Comparative study of deep levels in HVPE and MOCVD GaN by combining O-DLTS and pulsed photo-ionization spectroscopy

    NASA Astrophysics Data System (ADS)

    Pavlov, J.; Čeponis, T.; Gaubas, E.; Meskauskaite, D.; Reklaitis, I.; Vaitkus, J.; Grigonis, R.; Sirutkaitis, V.

    2015-12-01

    Operational characteristics of sensors made of GaN significantly depend on technologically introduced defects acting as rapid traps of excess carriers which reduce charge collection efficiency of detectors. In order to reveal the prevailing defects in HVPE and MOCVD grown GaN, the carrier lifetime and photo-ionization spectra have been simultaneously measured by using microwave probed photo-conductivity transient technique. Several traps ascribed to impurities as well as vacancy and anti-site type defects have been identified in HVPE GaN material samples by combining photo-ionization and electron spin resonance spectroscopy. The optical deep level transient spectroscopy technique has been applied for spectroscopy of the parameters of thermal emission from the traps ascribed to technological defects in the Schottky barrier terrace structures fabricated on MOCVD GaN.

  11. DC and High Frequency Characterization of Metalorganic Chemical Vapor Deposition (MOCVD) Grown InP/InGaAs PNP Heterojunction Bipolar Transistor

    NASA Astrophysics Data System (ADS)

    Cui, Delong; Hsu, Shawn S. H.; Pavlidis, Dimitris

    2002-02-01

    InP/InGaAs PNP heterojunction bipolar transistor (HBT) layers have been grown by metalorganic chemical vapor deposition (MOCVD) and devices have been fabricated using a self-aligned processing technology. A zinc-doped InP layer has been employed as the wide-bandgap emitter layer for the PNP HBT. The base layer used a 500 Å thick n-type InGaAs layer doped at 5× 1018 cm-3. Successful high frequency operation of these devices has been demonstrated. A single-emitter 1× 20 μm2 MOCVD-grown PNP InP/InGaAs HBT achieved current gain cutoff frequency (fT) of more than 11 GHz at a current density (JC) of 8.25× 104 A/cm2.

  12. 10 GHz surface impedance measurements of (Y sub 9 Er)BaCuO films produced by MOCVD, laser ablation, and sputtering

    SciTech Connect

    Luine, J.; Daly, K.; Hu, R.; Kain, A.; Lee, A.; Manasevit, H.; Pettiette-Hall, C.; Simon, R.; St. John, D.; Wagner, M. )

    1991-03-01

    This paper reports on a parallel-plate resonator technique previously used to measure microwave surface resistance R{sub s}(T) extended to also measure absolute penetration depth {lambda}(T). Measurements of both quantities near 10 GHz from 4.2 K to Tc are reported for ErBaCuO thin films produced by metal-organic chemical vapor deposition (MOCVD) and YBaCuO think films produced by laser ablation and single-target off-axis sputtering. All the films were made at TRW. Each production method gives rise to films whose surface resistance is below 1 milliohm at temperatures below 40K. The low temperature penetration depths range from 250 nm for the laser ablation and sputtered films to 800 nm for the MOCVD films. The penetration depths in all cases increase with temperature according to the Gorter-Casimir temperature dependence.

  13. Injection System for Multi-Well Injection Using a Single Pump

    PubMed Central

    Wovkulich, Karen; Stute, Martin; Protus, Thomas J.; Mailloux, Brian J.; Chillrud, Steven N.

    2015-01-01

    Many hydrological and geochemical studies rely on data resulting from injection of tracers and chemicals into groundwater wells. The even distribution of liquids to multiple injection points can be challenging or expensive, especially when using multiple pumps. An injection system was designed using one chemical metering pump to evenly distribute the desired influent simultaneously to 15 individual injection points through an injection manifold. The system was constructed with only one metal part contacting the fluid due to the low pH of the injection solutions. The injection manifold system was used during a three-month pilot scale injection experiment at the Vineland Chemical Company Superfund site. During the two injection phases of the experiment (Phase I = 0.27 L/min total flow, Phase II = 0.56 L/min total flow), flow measurements were made 20 times over three months; an even distribution of flow to each injection well was maintained (RSD <4%). This durable system is expandable to at least 16 injection points and should be adaptable to other injection experiments that require distribution of air-stable liquids to multiple injection points with a single pump. PMID:26140014

  14. Silicone rod extraction followed by liquid desorption-large volume injection-programmable temperature vaporiser-gas chromatography-mass spectrometry for trace analysis of priority organic pollutants in environmental water samples.

    PubMed

    Delgado, Alejandra; Posada-Ureta, Oscar; Olivares, Maitane; Vallejo, Asier; Etxebarria, Nestor

    2013-12-15

    In this study a priority organic pollutants usually found in environmental water samples were considered to accomplish two extraction and analysis approaches. Among those compounds organochlorine compounds, pesticides, phthalates, phenols and residues of pharmaceutical and personal care products were included. The extraction and analysis steps were based on silicone rod extraction (SR) followed by liquid desorption in combination with large volume injection-programmable temperature vaporiser (LVI-PTV) and gas chromatography-mass spectrometry (GC-MS). Variables affecting the analytical response as a function of the programmable temperature vaporiser (PTV) parameters were firstly optimised following an experimental design approach. The SR extraction and desorption conditions were assessed afterwards, including matrix modification, time extraction, and stripping solvent composition. Subsequently, the possibility of performing membrane enclosed sorptive coating extraction (MESCO) as a modified extraction approach was also evaluated. The optimised method showed low method detection limits (3-35 ng L(-1)), acceptable accuracy (78-114%) and precision values (<13%) for most of the studied analytes regardless of the aqueous matrix. Finally, the developed approach was successfully applied to the determination of target analytes in aqueous environmental matrices including estuarine and wastewater samples.

  15. Simultaneous Qualitative and Quantitative Analysis of Multiple Chemical Constituents in YiQiFuMai Injection by Ultra-Fast Liquid Chromatography Coupled with Ion Trap Time-of-Flight Mass Spectrometry.

    PubMed

    Liu, Chunhua; Ju, Aichun; Zhou, Dazheng; Li, Dekun; Kou, Junping; Yu, Boyang; Qi, Jin

    2016-05-18

    YiQiFuMai injection (YQFM) is a modern lyophilized powder preparation derived from the traditional Chinese medicine Sheng-mai san (SMS) used for treating cardiovascular diseases, such as chronic heart failure. However, its chemical composition has not been fully elucidated, particularly for the preparation derived from Ophiopogon japonicus. This study aimed to establish a systematic and reliable method to quickly and simultaneously analyze the chemical constituents in YQFM by ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry (UFLC-IT-TOF/MS). Sixty-five compounds in YQFM were tentatively identified by comparison with reference substances or literature data. Furthermore, twenty-one compounds, including three ophiopogonins, fifteen ginsenosides and three lignans were quantified by UFLC-IT-TOF/MS. Notably, this is the first determination of steroidal saponins from O. japonicus in YQFM. The relative standard deviations (RSDs) of intra- and inter-day precision, reproducibility and stability were <4.9% and all analytes showed good linearity (R² ≥ 0.9952) and acceptable recovery of 91.8%-104.2% (RSD ≤ 5.4%), indicating that the methods were reliable. These methods were successfully applied to quantitative analysis of ten batches of YQFM. The developed approach can provide useful and comprehensive information for quality control, further mechanistic studies in vivo and clinical application of YQFM.

  16. Differentiating organically and conventionally grown oregano using ultraperformance liquid chromatography mass spectrometry (UPLC-MS), headspace gas chromatography with flame ionization detection (headspace-GC-FID), and flow injection mass spectrum (FIMS) fingerprints combined with multivariate data analysis.

    PubMed

    Gao, Boyan; Qin, Fang; Ding, Tingting; Chen, Yineng; Lu, Weiying; Yu, Liangli Lucy

    2014-08-13

    Ultraperformance liquid chromatography mass spectrometry (UPLC-MS), flow injection mass spectrometry (FIMS), and headspace gas chromatography (headspace-GC) combined with multivariate data analysis techniques were examined and compared in differentiating organically grown oregano from that grown conventionally. It is the first time that headspace-GC fingerprinting technology is reported in differentiating organically and conventionally grown spice samples. The results also indicated that UPLC-MS, FIMS, and headspace-GC-FID fingerprints with OPLS-DA were able to effectively distinguish oreganos under different growing conditions, whereas with PCA, only FIMS fingerprint could differentiate the organically and conventionally grown oregano samples. UPLC fingerprinting provided detailed information about the chemical composition of oregano with a longer analysis time, whereas FIMS finished a sample analysis within 1 min. On the other hand, headspace GC-FID fingerprinting required no sample pretreatment, suggesting its potential as a high-throughput method in distinguishing organically and conventionally grown oregano samples. In addition, chemical components in oregano were identified by their molecular weight using QTOF-MS and headspace-GC-MS.

  17. Multi-wafer growth of GaInAs photodetectors on 4" InP by MOCVD for SWIR imaging applications

    NASA Astrophysics Data System (ADS)

    Furlong, Mark J.; Mattingley, Mark; Lim, Sung Wook; Geen, Matthew; Jones, Wynne

    2014-06-01

    Photodiodes based on the GaInAs/InP material system responding in the 1.3-1.7 μm wavelength range are of interest in a wide range of applications, from optical power and channel monitors in telecommunication systems through to advanced night vision imaging using large format focal plane type detectors for defense and security applications. Here we report on our results of GaInAs PIN photo detector structures grown on 2", 3" and 4" InP substrates by low pressure Metalorganic Chemical Vapor Deposition (MOCVD) in both standard and new larger volume format reactor configurations. High quality, lattice matched InP/GaInAs epitaxial layers were grown and we demonstrate that when moving to larger platen configurations, high degree of thickness uniformity (<3%, FTIR), lattice mismatch (<0.1%, XRD) and compositional uniformity (<2 nm, PL) can be maintained. The surface quality of epitaxial wafers will be assessed by various surface analytical techniques. We also make comparisons with the performance of 2", 3" and 4" photodetector structures grown, this demonstrating that MOCVD production processes have been successfully scaled. We conclude by discussing the material requirements for large area infrared focal plane array photodetectors and describe how MOCVD growth technology will address industry's requirements for increasing device sizes with improved performance.

  18. Sodium storage and injection system

    NASA Technical Reports Server (NTRS)

    Keeton, A. R. (Inventor)

    1979-01-01

    A sodium storage and injection system for delivering atomized liquid sodium to a chemical reactor employed in the production of solar grade silicon is disclosed. The system is adapted to accommodate start-up, shut-down, normal and emergency operations, and is characterized by (1) a jacketed injection nozzle adapted to atomize liquefied sodium and (2) a supply circuit connected to the nozzle for delivering the liquefied sodium. The supply circuit is comprised of a plurality of replaceable sodium containment vessels, a pump interposed between the vessels and the nozzle, and a pressurizing circuit including a source of inert gas connected with the vessels for maintaining the sodium under pressure.

  19. Capsule injection system for a hydraulic capsule pipelining system

    DOEpatents

    Liu, Henry

    1982-01-01

    An injection system for injecting capsules into a hydraulic capsule pipelining system, the pipelining system comprising a pipeline adapted for flow of a carrier liquid therethrough, and capsules adapted to be transported through the pipeline by the carrier liquid flowing through the pipeline. The injection system comprises a reservoir of carrier liquid, the pipeline extending within the reservoir and extending downstream out of the reservoir, and a magazine in the reservoir for holding capsules in a series, one above another, for injection into the pipeline in the reservoir. The magazine has a lower end in communication with the pipeline in the reservoir for delivery of capsules from the magazine into the pipeline.

  20. SLIC Simulation-Based Liquid Injection Control

    DTIC Science & Technology

    2007-11-02

    Artificial Intelligence Optimized Design For RTM / VARTM Sensors & Recognition Algorithms Process Monitoring Control Algorithms Feedback Control...of Online Flow Control Solution Advantages of developing RTM / VARTM with SLIC • Rapid design for RTM / VARTM . • Less cost for process development...User Manual • Examples • Tutorials Probability Model FASTRAC Flow Control in VARTM RTM Light Optimization Preform Distribution Media 1 Jul 2003

  1. A novel method for the rapid determination of polyethoxylated tallow amine surfactants in water and sediment using large volume injection with high performance liquid chromatography and tandem mass spectrometry.

    PubMed

    Ross, Andrew R S; Liao, Xiangjun

    2015-08-19

    Polyethoxylated tallow amine (POEA) surfactants have been used in many glyphosate-based herbicide formulations for agricultural, industrial and residential weed control. The potential for release of these compounds into the environment is of increasing concern due to their toxicity towards aquatic organisms. Current methods for analysis of POEA surfactants require significant time and effort to achieve limits of quantification that are often higher than the concentrations at which biological effects have been observed (as low as 2 ng mL(-1)). We have developed a rapid and robust method for quantifying the POEA surfactant mixture MON 0818 at biologically relevant concentrations in fresh water, sea water and lake sediment using reversed phase high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry. Water samples preserved by 1:1 v/v dilution with methanol are analyzed directly following centrifugation. Sediment samples undergo accelerated solvent extraction in aqueous methanol prior to analysis. Large volume (100 μL) sample injection and multiple reaction monitoring of a subset of the most abundant POEA homologs provide limits of quantification of 0.5 and 2.9 ng mL(-1) for MON 0818 in fresh water and sea water, respectively, and 2.5 ng g(-1) for total MON 0818 in lake sediment. Average recoveries of 93 and 75% were achieved for samples of water and sediment, respectively spiked with known amounts of MON 0818. Precision and accuracy for the analysis of water and sediment samples were within 10 and 16%, respectively based upon replicate analyses of calibration standards and representative samples. Results demonstrate the utility of the method for quantifying undegraded MON 0818 in water and sediment, although a more comprehensive method may be needed to identify and determine other POEA mixtures and degradation profiles that might occur in the environment.

  2. Stir-bar-sorptive extraction and liquid desorption combined with large-volume injection gas chromatography-mass spectrometry for ultra-trace analysis of musk compounds in environmental water matrices.

    PubMed

    Silva, Ana Rita M; Nogueira, J M F

    2010-03-01

    Stir-bar-sorptive extraction with liquid desorption followed by large-volume injection and capillary gas chromatography coupled to mass spectrometry in selected ion monitoring acquisition mode (SBSE-LD/LVI-GC-MS(SIM)) has been developed to monitor ultra-traces of four musks (celestolide (ADBI), galaxolide (HHCB), tonalide (AHTN) and musk ketone (MK)) in environmental water matrices. Instrumental calibration (LVI-GC-MS(SIM)) and experimental conditions that could affect the SBSE-LD efficiency are discussed. Assays performed on 30-mL water samples spiked at 200 ng L(-1) under optimized experimental conditions yielded recoveries ranging from 83.7 ± 8.1% (MK) to 107.6 ± 10.8% (HHCB). Furthermore, the experimental data were in very good agreement with predicted theoretical equilibria described by octanol-water partition coefficients (K (PDMS/W) ≈ K (O/W)). The methodology also showed excellent linear dynamic ranges for the four musks studied, with correlation coefficients higher than 0.9961, limits of detection and quantification between 12 and 19 ng L(-1) and between 41 and 62 ng L(-1), respectively, and suitable precision (< 20%). Application of this method for analysis of the musks in real water matrices such as tap, river, sea, and urban wastewater samples resulted in convenient selectivity, high sensitivity and accuracy using the standard addition methodology. The proposed method (SBSE-LD/LVI-GC-MS(SIM)) was shown to be feasible and sensitive, with a low-sample volume requirement, for determination of musk compounds in environmental water matrices at the ultra-trace level, overcoming several disadvantages presented by other sample-preparation techniques.

  3. Development of a fully automated sequential injection solid-phase extraction procedure coupled to liquid chromatography to determine free 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid in human urine.

    PubMed

    León, Zacarías; Chisvert, Alberto; Balaguer, Angel; Salvador, Amparo

    2010-04-07

    2-Hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid, commonly known as benzophenone-3 (BZ3) and benzophenone-4 (BZ4), respectively, are substances widely used as UV filters in cosmetic products in order to absorb UV radiation and protect human skin from direct exposure to the deleterious wavelengths of sunlight. As with other UV filters, there is evidence of their percutaneous absorption. This work describes an analytical method developed to determine trace levels of free BZ3 and BZ4 in human urine. The methodology is based on a solid-phase extraction (SPE) procedure for clean-up and pre-concentration, followed by the monitoring of the UV filters by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). In order to improve not only the sensitivity and selectivity, but also the precision of the method, the principle of sequential injection analysis was used to automate the SPE process and to transfer the eluates from the SPE to the LC system. The application of a six-channel valve as an interface for the switching arrangements successfully allowed the on-line connection of SPE sample processing with LC analysis. The SPE process for BZ3 and BZ4 was performed using octadecyl (C18) and diethylaminopropyl (DEA) modified silica microcolumns, respectively, in which the analytes were retained and eluted selectively. Due to the matrix effects, the determination was based on standard addition quantification and was fully validated. The relative standard deviations of the results were 13% and 6% for BZ3 and BZ4, respectively, whereas the limits of detection were 60 and 30 ng mL(-1), respectively. The method was satisfactorily applied to determine BZ3 and BZ4 in urine from volunteers that had applied a sunscreen cosmetic containing both UV filters.

  4. Catalyst-free growth of ZnO nanowires by metal-organic chemical vapour deposition (MOCVD) and thermal evaporation

    SciTech Connect

    Lee, Woong; Jeong, Min-Chang; Myoung, Jae-Min

    2004-08-02

    ZnO nanowires were grown on GaAs(0 0 2) substrates using metal-organic chemical vapour deposition (MOCVD) and on Si(0 0 1) substrates using thermal evaporation of source powders, respectively. It was demonstrated that well-aligned single crystalline nanowires could be grown with controlled sizes using a typical thin film deposition technique without catalysts. Arsenic doping of the ZnO nanowires grown on GaAs substrate was possible using post-growth heat-treatment, proposing a possible way of producing p-type ZnO nanowires. It was also shown that simplified process of carrier-free thermal evaporation without catalyst could be employed to grow nanowires with high yield while maintaining good crystalline and optical properties. Application potential of the nanowires as probes of atomic force microscopes (AFMs) was discussed by predicting their structural compatibility with AFM cantilevers based on continuum elasticity. It was predicted that the nanowires fabricated herein are structurally compatible with typical AFM cantilevers suggesting that they are promising candidates for high aspect ratio probes.

  5. Advanced light-scattering materials: Double-textured ZnO:B films grown by LP-MOCVD

    NASA Astrophysics Data System (ADS)

    Addonizio, M. L.; Spadoni, A.; Antonaia, A.

    2013-12-01

    Double-textured ZnO:B layers with enhanced optical scattering in both short and long wavelength regions have been successfully fabricated using MOCVD technique through a three step process. Growth of double-textured structures has been induced by wet etching on polycrystalline ZnO surface. Our double-layer structure consists of a first ZnO:B layer wet etched and subsequently used as substrate for a second ZnO:B layer deposition. Polycrystalline ZnO:B layers were etched by utilizing diluted solutions of fluoridic acid (HF), chloridric acid (HCl) and phosphoric acid (H3PO4) and their effect on surface morphology modification was systematically investigated. The morphology of the second deposited ZnO layer strongly depended on the surface properties of the etched ZnO first layer. Growth of cauliflower-like texture was induced by protrusions presence on the HCl etched surface. Optimized double-layer structure shows a cauliflower-like double texture with higher RMS roughness and increased spectral haze values in both short and long wavelength regions, compared to conventional pyramidal-like single texture. Furthermore, this highly scattering structure preserves excellent optical and electrical properties.

  6. Vertically p-n-junctioned GaN nano-wire array diode fabricated on Si(111) using MOCVD.

    PubMed

    Park, Ji-Hyeon; Kim, Min-Hee; Kissinger, Suthan; Lee, Cheul-Ro

    2013-04-07

    We demonstrate the fabrication of n-GaN:Si/p-GaN:Mg nanowire arrays on (111) silicon substrate by metal organic chemical vapor deposition (MOCVD) method .The nanowires were grown by a newly developed two-step growth process. The diameter of as-grown nanowires ranges from 300-400 nm with a density of 6-7 × 10(7) cm(-2). The p- and n-type doping of the nanowires is achieved with Mg and Si dopant species. Structural characterization by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) indicates that the nanowires are relatively defect-free. The room-temperature photoluminescence emission with a strong peak at 370 nm indicates that the n-GaN:Si/p-GaN:Mg nanowire arrays have potential application in light-emitting nanodevices. The cathodoluminscence (CL) spectrum clearly shows a distinct optical transition of GaN nanodiodes. The nano-n-GaN:Si/p-GaN:Mg diodes were further completed using a sputter coating approach to deposit Au/Ni metal contacts. The polysilazane filler has been etched by a wet chemical etching process. The n-GaN:Si/p-GaN:Mg nanowire diode was fabricated for different Mg source flow rates. The current-voltage (I-V) measurements reveal excellent rectifying properties with an obvious turn-on voltage at 1.6 V for a Mg flow rate of 5 sccm (standard cubic centimeters per minute).

  7. Broad Temperature Pinning Study of 15 mol.% Zr-Added (Gd, Y)-Ba-Cu-O MOCVD Coated Conductors

    SciTech Connect

    Xu, AX; Khatri, N; Liu, YH; Majkic, G; Galstyan, E; Selvamanickam, V; Chen, YM; Lei, CH; Abraimov, D; Hu, XB; Jaroszynski, J; Larbalestier, D

    2015-06-01

    BaZrO3 (BZO) nanocolumns have long been shown to be very effective for raising the pinning force F-p of REBa2Cu3Ox (REBCO, where RE = rare earth) films at high temperatures and recently at low temperatures too. We have successfully incorporated a high density of BZO nanorods into metal organic chemical vapor deposited (MOCVD) REBCO coated conductors via Zr addition. We found that, compared to the 7.5% Zr-added coated conductor, dense BZO nanorod arrays in the 15% Zr-added conductor are effective over the whole temperature range from 77 K down to 4.2 K. We attribute the substantially enhanced J(c) at 30 K to the weak uncorrelated pinning as well as the strong correlated pinning. Meanwhile, by tripling the REBCO layer thickness to similar to 2.8 mu m, the engineering critical current density J(e) at 30 K exceeds J(e) of optimized Nb-Ti wires at 4.2 K.

  8. Investigation on structural, optical and electrical properties of Cp2Mg flow varied p-GaN grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Surender, S.; Pradeep, S.; Ramesh, R.; Baskar, K.

    2016-05-01

    In this work the effect of different concentration of Magnesium doped GaN (p-GaN) were systematically studied. The p-GaN epilayers were grown on c-plane sapphire substrate by horizontal flow Metal Organic Chemical Vapor Deposition (MOCVD) with various flow rates of 100 sccm to 300 sccm using bis-(cyclopentadienyl) - magnesium (Cp2Mg) precursor. The samples were subjected to structural, optical, morphological and electrical studies using High Resolution X-ray diffraction (HRXRD), room temperature photoluminescence (PL), Atomic Force Microscopy (AFM) and Hall measurement respectively. Results indicated that the Mg doped GaN of 200 sccm Cp2Mg has the root mean square (rms) roughness of about 0.3 nm for a scan area of 5×5 µm2 which has good two dimensional growth. Moreover, Hall measurements results shows that (200 sccm Cp2Mg) Mg-doped GaN possess the highest hole concentration of 5.4×1017cm-3 and resistivity of 1.7 Ωcm at room temperature.

  9. Maximum magnitude earthquakes induced by fluid injection

    NASA Astrophysics Data System (ADS)

    McGarr, A.

    2014-02-01

    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  10. Computational analysis of GaN/InGaN deposition in MOCVD vertical rotating disk reactors

    NASA Astrophysics Data System (ADS)

    Kadinski, L.; Merai, V.; Parekh, A.; Ramer, J.; Armour, E. A.; Stall, R.; Gurary, A.; Galyukov, A.; Makarov, Yu.

    2004-01-01

    Calculation models that adequately represent the effects of process parameters (such as reactor pressure, shroud and reactants flow) and reactor geometry (such as injector and reactor chamber design) on growth rate and uniformity of GaN/InGaN in the EMCORE's D180 and E300 platforms have been developed. It has been proven that the use of very detailed three-dimensional geometrical models is of crucial importance for accurate predictions. Recent modeling of growth processes within the D180 and E300 systems has lead to improvements in the design and operation of the tools for the growth of GaN/InGaN structures. The following paper outlines the results of one of these improvements: a modification to the alkyl injection system, which improves growth uniformity and alkyl efficiency while optimizing uniformity tuning for a variety of reactor conditions during LED process development.

  11. Sc2O3, Er2O3, and Y2O3 thin films by MOCVD from volatile guanidinate class of rare-earth precursors.

    PubMed

    Milanov, Andrian P; Xu, Ke; Cwik, Stefan; Parala, Harish; de los Arcos, Teresa; Becker, Hans-Werner; Rogalla, Detlef; Cross, Richard; Paul, Shashi; Devi, Anjana

    2012-12-07

    Alternative novel precursor chemistries for the vapor phase deposition of rare-earth (RE) oxide thin films were developed by synthesising the homoleptic guanidinate compounds tris(N,N'-diisopropyl-2-dimethylamidoguanidinato)-scandium(III) [Sc(DPDMG)(3)] (1), tris(N,N'-diisopropyl-2-dimethylamidoguanidinato)-erbium(III), [Er(DPDMG)(3)] (2) and tris(N,N'-diisopropyl-2-dimethylamidoguanidinato)-yttrium(III), [Y(DPDMG)(3)] (3). All three compounds are monomeric as revealed by single crystal X-ray diffraction (XRD) analysis, nuclear magnetic resonance (NMR) and electron impact mass spectrometry (EI-MS). The thermal analysis revealed that the compounds are volatile and very stable under evaporation conditions. Therefore the complexes were evaluated as precursors for the growth of Sc(2)O(3), Er(2)O(3) and Y(2)O(3) thin films, respectively, by metal-organic chemical vapor deposition (MOCVD). Uniform Sc(2)O(3), Er(2)O(3) and Y(2)O(3) films on Si(100) substrates with reproducible quality were grown by MOCVD by the combination of the respective guanidinate precursors and oxygen in the temperature range 350-700 °C. The structural, morphological, compositional and electrical properties of the films were investigated in detail. The most relevant film properties are highlighted in relation to the distinct advantages of the novel precursor chemistries in comparison to the commonly used literature known RE precursors. This study shows that compounds 1-3 are very good precursors for MOCVD yielding Sc(2)O(3), Er(2)O(3) and Y(2)O(3) thin films which are stoichiometric and display suitable electrical properties for their potential use as high dielectric constant (high-k) materials.

  12. Fast Ignition and Sustained Combustion of Ionic Liquids

    NASA Technical Reports Server (NTRS)

    Joshi, Prakash B. (Inventor); Piper, Lawrence G. (Inventor); Oakes, David B. (Inventor); Sabourin, Justin L. (Inventor); Hicks, Adam J. (Inventor); Green, B. David (Inventor); Tsinberg, Anait (Inventor); Dokhan, Allan (Inventor)

    2016-01-01

    A catalyst free method of igniting an ionic liquid is provided. The method can include mixing a liquid hypergol with a HAN (Hydroxylammonium nitrate)-based ionic liquid to ignite the HAN-based ionic liquid in the absence of a catalyst. The HAN-based ionic liquid and the liquid hypergol can be injected into a combustion chamber. The HAN-based ionic liquid and the liquid hypergol can impinge upon a stagnation plate positioned at top portion of the combustion chamber.

  13. Growth and characterization of In{sub X}Ga{sub 1-X}N/GaN single quantum well prepared by MOCVD

    SciTech Connect

    Prabakaran, K.; Ramesh, R.; Jayasakthi, M.; Loganathan, R.; Arivazhagan, P.; Baskar, K.

    2015-06-24

    The InGaN/GaN SQW structures were grown on c-plane sapphire substrate using metal-organic chemical vapor deposition (MOCVD). The thickness and indium composition of the InGaN was determined by HRXRD. From simulation fit the composition of indium was found to be 10% and thickness was around 5nm and 10nm. The Photoluminescence emission was found to be shifited towards lower wavelength as 479nm, 440nm on increasing the thickness. The photoluminescence intensity was degrades with increases of InGaN thickness. Atomic force microscopy studies were also carried out and the results are discussed in detail.

  14. Structural and optical investigations of Al xGa 1- xAs:Si/GaAs(1 0 0) MOCVD heterostructures

    NASA Astrophysics Data System (ADS)

    Seredin, P. V.; Glotov, A. V.; Domashevskaya, E. P.; Arsentyev, I. N.; Vinokurov, D. A.; Tarasov, I. S.

    2010-11-01

    Al xGa 1- xAs:Si/GaAs(1 0 0) heterostructure and homoepitaxial GaAs:Si/GaAs(1 0 0) structures grown by MOCVD were investigated. The changes observed in our experiments with highly doped Al xGa 1- xAs alloys, led not only to the reconstruction of the electron density and formation of deep levels (DX-centers) with subsequent relaxation of the crystal lattice in the alloy, but also indicate at the formation of quaternary Al xGa 1- x- ySi y+ zAs 1- z substitution-type alloy grown on GaAs(1 0 0).

  15. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Analysis and finite element simulation of electromagnetic heating in the nitride MOCVD reactor

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Ming; Hao, Yue; Zhang, Jin-Cheng; Xu, Sheng-Rui; Ni, Jin-Yu; Zhou, Xiao-Wei

    2009-11-01

    Electromagnetic field distribution in the vertical metal organic chemical vapour deposition (MOCVD) reactor is simulated by using the finite element method (FEM). The effects of alternating current frequency, intensity, coil turn number and the distance between the coil turns on the distribution of the Joule heat are analysed separately, and their relations to the value of Joule heat are also investigated. The temperature distribution on the susceptor is also obtained. It is observed that the results of the simulation are in good agreement with previous measurements.

  16. High and low energy proton radiation damage in p/n InP MOCVD solar cells

    NASA Technical Reports Server (NTRS)

    Rybicki, George; Weinberg, Irving; Scheiman, Dave; Vargas-Aburto, Carlos

    1995-01-01

    InP p(+)nn(+) MOCVD solar cells were irradiated with 0.2 MeV and 10 MeV protons to a fluence of 10(exp 13)/sq cm. The degradation of power output, IV behavior, carrier concentration and defect concentration were observed at intermediate points throughout the irradiations. The 0.2 MeV proton irradiated solar cells suffered much greater and more rapid degradation in power output than those irradiated with 10 meV protons. The efficiency losses were accompanied by larger increases in the recombination currents in the 0.2 MeV proton irradiated solar cells. The low energy proton irradiations also had a larger impact on the series resistance of the solar cells. Despite the radiation induced damage, the carrier concentration in the base of the solar cells showed no reduction after 10 MeV or 0.2 MeV proton irradiations and even increased during irradiation with 0.2 MeV protons. In a DLTS study of the irradiated samples, the minority carrier defects H4 and H5 at E(v) + 0.33 and E(v) + 0.52 eV and the majority carrier defects E7 and E10 at E(c)- 0.39 and E(c)-0.74 eV, were observed. The defect introduction rates for the 0.2 MeV proton irradiations were about 20 times higher than for the 10 MeV proton irradiations. The defect E10, observed here after irradiation, has been shown to act as a donor in irradiated n-type InP and may be responsible for obscuring carrier removal. The results of this study are consistent with the much greater damage produced by low energy protons whose limited range causes them to stop in the active region of the solar cell.

  17. LP-MOCVD growth of GaAlN/GaN heterostructures on silicon carbide: application to HEMT devices

    NASA Astrophysics Data System (ADS)

    di Forte Poisson, M.-A.; Magis, M.; Tordjman, M.; Aubry, R.; Sarazin, N.; Peschang, M.; Morvan, E.; Delage, S. L.; di Persio, J.; Quéré, R.; Grimbert, B.; Hoel, V.; Delos, E.; Ducatteau, D.; Gaquiere, C.

    2004-12-01

    This paper reports on the LP-MOCVD growth optimisation of GaAlN/GaN heterostructures grown on silicon carbide substrates for HEMT applications, and on the first device performances obtained with these structures. The critical impact of some growth parameters on the physical properties of the GaAlN/GaN epilayers has been identified and studied using high-resolution X-ray diffraction, AFM, C-V and sonogauge measurements. SiC substrates from different suppliers were evaluated and their influence on the physical properties of the GaAlN/GaN HEMT structures were investigated. We show that the static characteristics of the devices such as maximum drain current Idss or pinch-off voltage are correlated with the nucleation layer composition ( GaN or GaAlN) of the HEMT structure and with the defect density of the SiC substrate. A maximum drain current Idss around 1 A/mm and a pinch-off voltage of -5 V have been measured for devices with a gate length of 0.3 μm and a GaN nucleation layer, to be compared to an Idss up to 1.3 A/mm obtained for devices with the same geometry but with a GaAlN nucleation layer. I-V characteristics measured under pulsed measurements have also evidenced a clear impact of the nucleation layer composition on the trap density in the GaAlN/GaN HEMT structure. The first devices related to HEMT wafers with GaN nucleation layers were measured at 10 GHz using a load pull system. They show a CW output power in excess of 2.8 W/mm for a gate length of 0.5 μm, while devices related to HEMT wafers with GaAlN nucleation layer exhibit output power up to 4 W/mm at 10 GHz.

  18. Monomeric malonate precursors for the MOCVD of HfO2 and ZrO2 thin films.

    PubMed

    Pothiraja, Ramasamy; Milanov, Andrian; Parala, Harish; Winter, Manuela; Fischer, Roland A; Devi, Anjana

    2009-01-28

    New Hf and Zr malonate complexes have been synthesized by the reaction of metal amides with different malonate ligands (L = dimethyl malonate (Hdmml), diethyl malonate (Hdeml), di-tert-butyl malonate (Hdbml) and bis(trimethylsilyl) malonate (Hbsml)). Homoleptic eight-coordinated monomeric compounds of the type ML4 were obtained for Hf with all the malonate ligands employed. In contrast, for Zr only Hdmml and Hdeml yielded the eight-coordinated monomeric compounds of the type ML4, while using the bulky Hdbml and Hbsml ligands resulted into mixed alkoxo-malonato six-coordinated compounds of the type [ML2(OR)2]. Single crystal X-ray diffraction studies of all the compounds are presented and discussed, and they are found to be monomeric. The complexes are solids and in solution, they retain their monomeric nature as evidenced by NMR measurements. Compared to the classical beta-diketonate complexes, [M(acac)4] and [M(thd)4] (M = Hf, Zr; acac: acetylacetonate; thd: tetramethylheptadione), the new malonate compounds are more volatile, decompose at lower temperatures and have lower melting points. In particular, the homoleptic diethyl malonate complexes of Hf and Zr melt at temperatures as low as 62 degrees C. In addition, the compounds are very stable in air and can be sublimed quantitatively. The promising thermal properties makes these compounds interesting for metal-organic chemical vapor deposition (MOCVD). This was demonstrated by depositing HfO2 and ZrO2 thin films successfully with two representative Hf and Zr complexes.

  19. Analysis of rocket engine injection combustion processes

    NASA Technical Reports Server (NTRS)

    Salmon, J. W.

    1976-01-01

    A critique is given of the JANNAF sub-critical propellant injection/combustion process analysis computer models and application of the models to correlation of well documented hot fire engine data bases. These programs are the distributed energy release (DER) model for conventional liquid propellants injectors and the coaxial injection combustion model (CICM) for gaseous annulus/liquid core coaxial injectors. The critique identifies model inconsistencies while the computer analyses provide quantitative data on predictive accuracy. The program is comprised of three tasks: (1) computer program review and operations; (2) analysis and data correlations; and (3) documentation.

  20. Fabrication of YSZ buffer layer by single source MOCVD technique for YBCO coated conductor

    NASA Astrophysics Data System (ADS)

    Jun, Byung-Hyuk; Sun, Jong-Won; Kim, Ho-Jin; Lee, Dong-Wook; Jung, Choong-Hwan; Park, Soon-Dong; Kim, Chan-Joong

    2003-10-01

    Yttria stabilized zirconia (YSZ) buffer layers were deposited by a metal organic chemical vapor deposition technique using a single liquid source for the application of YBa 2Cu 3O 7- δ (YBCO) coated conductor. Y:Zr mole ratio was 0.2:0.8, and tetrahydrofuran (THF) was used as a solvent. The (1 0 0) single crystal MgO substrate was used for searching the deposition conditions. Bi-axially oriented CeO 2 and NiO films were fabricated on {1 0 0} <0 0 1> textured Ni substrate by the same method and used as templates. At a constant working pressure of 10 Torr, the deposition temperatures (660-800 °C) and oxygen flow rates (100-500 sccm) were changed to find the optimum deposition condition. The best (1 0 0) oriented YSZ film on MgO was obtained at 740 °C and O 2 flow rate of 300 sccm. For a YSZ buffer layer with this deposition condition on a CeO 2/Ni template, full width half maximum values of the in-plane ( ϕ-scan) and out-of-plane ( ω-scan) alignments were 10.6° and 9.8°, respectively. The SEM image of YSZ film on CeO 2/Ni showed surface morphologies without microcracks. The film deposition rate was about 100 nm/min.

  1. Liquid Wall Chambers

    SciTech Connect

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  2. Epidural Injections for Spinal Pain

    MedlinePlus

    ... Physician Resources Professions Site Index A-Z Epidural Injections An epidural injection provides temporary or prolonged relief ... limitations of Epidural Injection? What is an Epidural Injection? An epidural injection is an injection of medication ...

  3. Waterflooding injectate design systems and methods

    DOEpatents

    Brady, Patrick V.; Krumhansl, James L.

    2014-08-19

    A method of designing an injectate to be used in a waterflooding operation is disclosed. One aspect includes specifying data representative of chemical characteristics of a liquid hydrocarbon, a connate, and a reservoir rock, of a subterranean reservoir. Charged species at an interface of the liquid hydrocarbon are determined based on the specified data by evaluating at least one chemical reaction. Charged species at an interface of the reservoir rock are determined based on the specified data by evaluating at least one chemical reaction. An extent of surface complexation between the charged species at the interfaces of the liquid hydrocarbon and the reservoir rock is determined by evaluating at least one surface complexation reaction. The injectate is designed and is operable to decrease the extent of surface complexation between the charged species at interfaces of the liquid hydrocarbon and the reservoir rock. Other methods, apparatus, and systems are disclosed.

  4. High fidelity simulation of transcritical injection

    NASA Astrophysics Data System (ADS)

    Soteriou, Marios; Gao, Hui; Li, Xiaoyi; Davis, Dustin

    2012-11-01

    Transcritical injection of a multi-component fluid occurs in many practical applications such as diesel and rocket engines. In this type of injection a liquid fuel at a supercritical pressure but subcritical temperature, is introduced into an environment where conditions are supercritical. The convoluted physics of the transition from the subcritical to the supercritical state is linked to thermodynamic property variations and poses challenges to numerical simulation. For example, the temporary presence of surface tension implies that both the subcritical liquid-vapor interface and the transition boundary to supercritical fluid need to be captured. In this work, numerical simulation of a binary system of a subcritical liquid injecting into a supercritical, quiescent gaseous environment is performed. A coupled level set and volume of fluid method is adopted to capture the liquid-vapor interface, across which the continuity of mass and energy fluxes is preserved. The fluid state over the range of subcritical liquid to supercritical fluid is determined by incorporating the Peng-Robinson equation of state. To efficiently account for the sharp changes in properties near the liquid-vapor interface and the transition boundary to supercritical fluid, an adaptive mesh refinement technique is employed. Analysis of results focuses on the impact of vanishing surface tension as conditions transition from sub-critical to supercritical.

  5. Correlation of local structure peculiarities and critical current density of 2G MOCVD YBCO tapes with BaZrO3 nanoinclusions

    NASA Astrophysics Data System (ADS)

    Menushenkov, A. P.; Ivanov, V. G.; Chepikov, V. N.; Nygaard, R. R.; Soldatenko, A. V.; Rudnev, I. A.; Osipov, M. A.; Mineev, N. A.; Kaul, A. R.; Mathon, O.; Monteseguro, V.

    2017-04-01

    We have studied the influence of BaZrO3 nanoinclusions on the local structure and critical current density of second-generation high temperature superconducting tapes based on YBa2Cu3O7‑δ (YBCO) films. The films were made by metal–organic chemical vapor deposition (MOCVD). The crystal and local structure of the materials under study were analysed by x-ray diffraction and x-ray absorption spectroscopy (EXAFS + XANES). We have found that, being added at MOCVD process, Zr forms BaZrO3 nanoinclusions in YBCO matrix. The distance between Zr and the neighboring atoms is shorter than that one in a bulk crystalline BaZrO3, so we conclude that the nanoinclusions are in compressed state. The incorporation of 5 mol% BaZrO3 minimizes the static disorder of Cu–O bonds and maximizes their stiffness in YBCO. We show that the local structure peculiarities correlate well with the observed critical current behavior and consider this to be additional evidence in favor of small amounts of BaZrO3 nanoinclusions as efficient pinning centers.

  6. MOCVD growth and characterization of multi-stacked InAs/GaAs quantum dots on misoriented Si(100) emitting near 1.3 μm

    NASA Astrophysics Data System (ADS)

    Liu, Hao; Wang, Qi; Chen, Jia; Liu, Kai; Ren, Xiaomin

    2016-12-01

    We report near 1.3 μm strong photoluminescence (PL) emission from 5-stacked InAs/GaAs quantum dots (QDs) monolithically grown on Si (1 0 0) substrates with 4° miscut towards [110] direction by metal organic chemical vapor deposition (MOCVD). The metamorphic QD samples on Si were grown by three-step method, in which bottom Al0.8Ga0.2As cladding and GaAs waveguide layers were simultaneously incorporated in order to fabricate Si-based QD light emitting devices later. In particular, the GaAs waveguide layer grown with low and high temperature alternated significantly suppresses the upwards propagating of threading dislocations (TDs) into QD region and flattens the surface for latter adjacent nucleation of QDs. As a result, room-temperature photoluminescence intensity of as-grown Si-based InAs/GaAs QD sample attains 87% of that on GaAs and its PL peak as long as 1280 nm with the full width at half maximum value up to 78 nm (i.e., 60 meV). Our study shows the great opportunity of using MOCVD grown Si-based metamorphic QDs for 1.3 μm band light emitting devices.

  7. Beam Injection into RHIC

    NASA Astrophysics Data System (ADS)

    Fischer, W.; Hahn, H.; Mackay, W. W.; Tsoupas, N.

    1997-05-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. We describe the injection zone and its bottlenecks, the application program to steer the beam and the injection kickers. We report on the commissioning of the injection systems and on measurements of the kickers.

  8. Liquid propellant rockets.

    NASA Technical Reports Server (NTRS)

    Dipprey, D. F.

    1972-01-01

    A brief overview of the state of knowledge in liquid rocket technology is presented and examples are provided of instances where some fundamental principles of chemistry, fluid mechanics, and mathematics can be applied. A liquid propellant rocket classification is discussed together with rocket system performance, applications for liquid propellants, the effective exhaust velocity, aspects of simplified nozzle expansion, questions about theoretical propellant performance, the effect of chamber pressure on equilibrium performance, and the kinetic recombination in nozzles. Details of propellant combustion are examined, giving attention to propellant injection, evaporation-controlled combustion, combustion instability, and monopropellant decomposition.

  9. Enhanced liquid hydrocarbon recovery process

    SciTech Connect

    Sydansk, R.D.

    1992-07-14

    This patent describes a process for recovering liquid hydrocarbons. It comprises: injecting into a fractured subterranean formation a polymer enhanced foam comprising a polymer selected from a synthetic polymer or a biopolymer, a surfactant, an aqueous solvent and a gas, recovering liquid hydrocarbons from the formation.

  10. Miniaturized flow injection analysis system

    DOEpatents

    Folta, J.A.

    1997-07-01

    A chemical analysis technique known as flow injection analysis is described, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38{times}25{times}3 mm, but can be designed for gas analysis and be substantially smaller in construction. 9 figs.

  11. Miniaturized flow injection analysis system

    DOEpatents

    Folta, James A.

    1997-01-01

    A chemical analysis technique known as flow injection analysis, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38.times.25.times.3 mm, but can be designed for gas analysis and be substantially smaller in construction.

  12. High and Low Energy Proton Radiation Damage in p/n InP MOCVD Solar Cells

    NASA Technical Reports Server (NTRS)

    Rybicki, George; Weinberg, Irv; Scheiman, Dave; Vargas-Aburto, Carlos; Uribe, Roberto

    1995-01-01

    InP p(+)/n/n(+) solar cells, fabricated by metal organic chemical vapor deposition, (MOCVD) were irradiated with 0.2 MeV and 10 MeV protons to a fluence of 10(exp 13)/sq cm. The power output degradation, IV behavior, carrier concentration and defect concentration were observed at intermediate points throughout the irradiations. The 0.2 MeV proton-irradiated solar cells suffered much greater and more rapid degradation in power output than those irradiated with 10 MeV protons. The efficiency losses were accompanied by larger increases in the recombination currents in the 0.2 MeV proton-irradiated solar cells. The low energy proton irradiations also had a larger impact on the series resistance of the solar cells. Despite the radiation induced damage, the carrier concentration in the base of the solar cells showed no reduction after 10 MeV or 0.2 MeV proton irradiations and even increased during irradiation with 0.2 MeV protons. In a deep level transient spectroscopy (DLTS) study of the irradiated samples, the minority carrier defects H4 and H5 at E(sub v) + 0.33 and E(sub v) + 0.52 eV and the majority carrier defects E7 and El0 at E(sub c) - 0.39 and E(sub c) - 0.74 eV, were observed. The defect introduction rates for the 0.2 MeV proton irradiations were about 20 times higher than for the 10 MeV proton irradiations. The defect El0, observed here after irradiation, has been shown to act as a donor in irradiated n-type InP and may be responsible for obscuring carrier removal. The results of this study are consistent with the much greater damage produced by low energy protons whose limited range causes them to stop in the active region of the solar cell.

  13. Preparation of ZnO:CeO{sub 2-x} thin films by AP-MOCVD: Structural and optical properties

    SciTech Connect

    Torres-Huerta, A.M.; Dominguez-Crespo, M.A.; Brachetti-Sibaja, S.B.; Dorantes-Rosales, H.; Hernandez-Perez, M.A.; Lois-Correa, J.A.

    2010-09-15

    The growth of columnar CeO{sub 2}, ZnO and ZnO:CeO{sub 2-x} films on quartz and AA6066 aluminum alloy substrates by economic atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) is reported. A novel and efficient combination of metal acetylacetonate precursors as well as mild operating conditions were used in the deposition process. The correlation among crystallinity, surface morphology and optical properties of the as-prepared films was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and UV-vis spectroscopy. The synthesized films showed different crystallographic orientations depending on the ZnO and CeO{sub 2} lattice mismatch, cerium content and growth rate. The CeO{sub 2} films synthesized in this work showed plate-like compact structures as a result of the growth process typical of CVD. Both pure and ZnO:CeO{sub 2-x} films were obtained with a hexagonal structure and highly preferred orientation with the c-axis perpendicular to both substrates under the optimal deposition conditions. The microstructure was modified from dense, short round columns to round structures with cavities ('rose-flower-like' structures) and the typical ZnO morphology by controlling the cerium doping the film and substrate nature. High optical transmittance (>87%) was observed in the pure ZnO films. As for the ZnO:CeO{sub 2-x} films, the optical transmission was decreased and the UV absorption increased, which subsequently was affected by an increase in cerium content. This paper assesses the feasibility of using ZnO:CeO{sub 2-x} thin films as UV-absorbers in industrial applications. - Graphical abstract: TEM micrographs and their corresponding SAED pattern obtained for the as-deposited ZnO-CeO{sub 2-x} thin films for a Zn/Ce metallic ratio 16:9.

  14. Method and apparatus for transporting liquid slurries

    SciTech Connect

    Berry, G.F.; Lyczkowski, R.W.; Wang, Chi-Sheng.

    1991-01-01

    An improved method and device to prevent erosion of slurry transport devices is disclosed which uses liquid injection to prevent contact by the slurry composition with the inner surface of the walls of the transport system. A non-abrasive liquid is injected into the slurry transport system and maintains intimate contact with the entire inner surface of the transport system, thereby creating a fluid barrier between the nonabrasive liquid and the inner surface of the transport system which thereby prevents erosion.

  15. Fluid-Injection Tool for Inaccessible Areas

    NASA Technical Reports Server (NTRS)

    Myers, J. E.

    1982-01-01

    New tool injects liquids or gases into narrow crevices. Can be used to apply caulking and waterproofing compounds, adhesives, detergent, undercoats and oil and to aerate hard-to-reach places. Nozzle can reach into opening 1/32 inch wide to depth of more than 4 inches. Although thin, device is rigid and strong.

  16. SNS Injection Foil Experience

    SciTech Connect

    Cousineau, Sarah M; Galambos, John D; Kim, Sang-Ho; Ladd, Peter; Luck, Chris; Peters, Charles C; Polsky, Yarom; Shaw, Robert W; Macek, Robert James; Raparia, Deepak; Plum, Michael A

    2010-01-01

    The Spallation Neutron Source comprises a 1 GeV, 1.4 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H0 excited states created during the H charge exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and strike the foil and bracket. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we will detail these and other interesting failure mechanisms, and describe the improvements we have made to mitigate them.

  17. Simulated afterburner performance with hydrogen peroxide injection for thrust augmentation

    NASA Technical Reports Server (NTRS)

    Metzler, Allen J; Grobman, Jack S

    1956-01-01

    Combustion performance of three afterburner configurations was evaluated at simulated altitude flight conditions with liquid augmentation to the primary combustor. Afterburner combustion efficiency and stability were better with injection of high-strength hydrogen peroxide than with no injection or with water injection. Improvements were observed in afterburner configurations with and without flameholders and in a short-length afterburner. At a peroxide-air ratio of 0.3, combustion was stable and 85 to 90 percent efficient in all configurations tested. Calculated augmented net-thrust ratios for peroxide injection with afterburning were approximately 60 percent greater than those for water injection.

  18. The Mechanism of Atomization Accompanying Solid Injection

    NASA Technical Reports Server (NTRS)

    Castleman, R A , Jr

    1933-01-01

    A brief historical and descriptive account of solid injection is followed by a detailed review of the available theoretical and experimental data that seem to throw light on the mechanism of this form of atomization. It is concluded that this evidence indicates that (1) the atomization accompanying solid injection occurs at the surface of the liquid after it issues as a solid stream from the orifice; and (2) that such atomization has a mechanism physically identical with the atomization which takes place in an air stream, both being due merely to the formation, at the gas-liquid interface, of fine ligaments under the influence of the relative motion of gas and liquid, and to their collapse, under the influence of surface tension, to form the drops in the spray.

  19. Evaluation of sample injection precision in respect to sensitivity in capillary electrophoresis using various injection modes.

    PubMed

    Ciura, Krzesimir; Pawelec, Aleksandra; Buszewska-Forajta, Magdalena; Markuszewski, Michał Jan; Nowakowska, Joanna; Prahl, Adam; Wielgomas, Bartosz; Dziomba, Szymon

    2017-03-01

    A comparative study was conducted to assess the injection precision in capillary electrophoresis for cationic analytes (arecoline, codeine, papaverine). The precision was measured in respect to methods sensitivity in various injection modes in capillary electrophoresis: standard hydrodynamic injection (3.45 kPa for 6 s), large volume sample stacking (3.45 kPa for 40 s), and field-amplified sample injection (10 kV for 65 s). All measurements were conducted for aqueous solutions of standards to minimize the errors linked to the sample preparation step. The methods were submitted to precision assessment at three concentration levels: at the limit of quantification, three-fold and ten-fold of limit of quantification. The results were compared to those from high-performance liquid chromatography as a reference technique. The field-amplified sample injection method was shown to provide greatest sensitivity (quantification limits down to 4 ng/mL for all three tested compounds) but the lowest precision. High-performance liquid chromatography was established as the most reliable technique (coefficient of variation in all intraday experiments was below 1%). It was also shown that with a use of large volume sample injection technique, similar sensitivity as in high-performance liquid chromatography can be easily reached.

  20. Water-cooled insulated steam-injection wells

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Jaffe, L. D.

    1980-01-01

    Water is used as insulated coolant and heat-transfer medium for steam-injection oil wells. Approach is somewhat analogous to cooling system in liquid-propellant rocket. In addition to trapping and delivering heat to steam-injection point, water will also keep casing cooler, preventing or reducing casing failures caused by thermal stresses.

  1. Iron Sucrose Injection

    MedlinePlus

    Iron sucrose injection is used treat iron-deficiency anemia (a lower than normal number of red blood cells due ... and may cause the kidneys to stop working). Iron sucrose injection is in a class of medications called iron ...

  2. Antigen injection (image)

    MedlinePlus

    Leprosy is caused by the organism Mycobacterium leprae . The leprosy test involves injection of an antigen just under ... if your body has a current or recent leprosy infection. The injection site is labeled and examined ...

  3. Corticotropin, Repository Injection

    MedlinePlus

    ... age; episodes of symptoms in people who have multiple sclerosis (MS; a disease in which the nerves do ... When corticotropin repository injection is used to treat multiple sclerosis, it is usually injected once a day for ...

  4. Sodium Ferric Gluconate Injection

    MedlinePlus

    Sodium ferric gluconate injection is used to treat iron-deficiency anemia (a lower than normal number of ... are also receiving the medication epoetin (Epogen, Procrit). Sodium ferric gluconate injection is in a class of ...

  5. Amphotericin B Liposomal Injection

    MedlinePlus

    Amphotericin B liposomal injection is used to treat fungal infections such as cryptococcal meningitis (a fungal infection of the ... infections in people who cannot receive conventional amphotericin B therapy. Amphotericin B liposomal injection is in a ...

  6. Calcitonin Salmon Injection

    MedlinePlus

    Calcitonin salmon injection is used to treat osteoporosis in postmenopausal women. Osteoporosis is a disease that causes bones to weaken and break more easily. Calcitonin salmon injection is also used to ...

  7. Urinary incontinence - injectable implant

    MedlinePlus

    Intrinsic sphincter deficiency repair; ISD repair; Injectable bulking agents for stress urinary incontinence ... Urine leakage that gets worse Pain where the injection was done Allergic reaction to the material Implant ...

  8. Slit injection device

    DOEpatents

    Alger, Terry W.; Schlitt, Leland G.; Bradley, Laird P.

    1976-06-15

    A laser cavity electron beam injection device provided with a single elongated slit window for passing a suitably shaped electron beam and means for varying the current density of the injected electron beam.

  9. Hip joint injection

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/007633.htm Hip joint injection To use the sharing features on this ... injection is a shot of medicine into the hip joint. The medicine helps relieve pain and inflammation. It ...

  10. Aminocaproic Acid Injection

    MedlinePlus

    Aminocaproic acid injection is used to control bleeding that occurs when blood clots are broken down too quickly. This ... the baby is ready to be born). Aminocaproic acid injection is also used to control bleeding in ...

  11. Deoxycholic Acid Injection

    MedlinePlus

    Deoxycholic acid injection is used to improve the appearance and profile of moderate to severe submental fat ('double chin'; fatty tissue located under the chin). Deoxycholic acid injection is in a class of medications called ...

  12. Active waste-injection systems in Florida, 1976

    USGS Publications Warehouse

    Vecchioli, John; McKenzie, D.J.; Pascale, C.A.; Wilson, W.E.

    1979-01-01

    As of the end of 1976, seven systems were injecting liquid wastes into Florida 's subsurface environment at a combined average rate of 15 million gallons per day. This report presents for each of these systems information on the kind and amount of waste injected and type of pretreatment, construction characteristics of the injection and monitor wells, type of test and monitoring data available, and brief discussion of any operational problems experienced. (Kosco-USGS)

  13. Rich catalytic injection

    DOEpatents

    Veninger, Albert

    2008-12-30

    A gas turbine engine includes a compressor, a rich catalytic injector, a combustor, and a turbine. The rich catalytic injector includes a rich catalytic device, a mixing zone, and an injection assembly. The injection assembly provides an interface between the mixing zone and the combustor. The injection assembly can inject diffusion fuel into the combustor, provides flame aerodynamic stabilization in the combustor, and may include an ignition device.

  14. Jet injection into polyacrylamide gels: investigation of jet injection mechanics.

    PubMed

    Schramm-Baxter, Joy; Katrencik, Jeffrey; Mitragotri, Samir

    2004-08-01

    Jet injectors employ high-velocity liquid jets that penetrate into human skin and deposit drugs in the dermal or subdermal region. Although jet injectors have been marketed for a number of years, relatively little is known about the interactions of high-speed jets with soft materials such as skin. Using polyacrylamide gels as a model system, the mechanics of jet penetration, including the dependence of jet penetration on mechanical properties, was studied. Jets employed in a typical commercial injector, (orifice diameter: 152 microm, velocity: 170-180 m/s) were used to inject fluid into polyacrylamide gels possessing Young's moduli in the range of 0.06-0.77 MPa and hardness values in the range of 4-70 H(OO). Motion analysis of jet entry into polyacrylamide gels revealed that jet penetration can be divided into three distinct events: erosion, stagnation, and dispersion. During the erosion phase, the jet removed the gel at the impact site and led to the formation of a distinct cylindrical hole. Cessation of erosion induced a period of jet stagnation ( approximately 600 micros) characterized by constant penetration depth. This stage was followed by dispersion of the liquid into the gel. The dispersion took place by crack propagation and was nearly symmetrical with the exception of injections into 10% acrylamide (Young's modulus of 0.06 MPa). The penetration depth of the jets as well as the rate of erosion decreased with increasing Young's modulus. The mechanics of jet penetration into polyacrylamide gels provides an important tool for understanding jet injection into skin.

  15. Beam injection into RHIC

    SciTech Connect

    Fischer, W.; Hahn, H.; MacKay, W.W.; Satogata, T.; Tsoupas, N.; Zhang, W.

    1997-07-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. The authors describe the injection zone and its bottlenecks. They report on the commissioning of the injection system, on beam based measurements of the kickers and the application program to steer the beam.

  16. Effect of Al-mole fraction in Al{sub x}Ga{sub 1−x}N grown by MOCVD

    SciTech Connect

    Jayasakthi, M. Ramesh, R. Prabakaran, K. Loganathan, R. Kuppulingam, B. Balaji, M. Arivazhagan, P. Sankaranarayanan, S. Singh, Shubra Baskar, K.

    2014-04-24

    AlGaN/AlN layers were grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. The Al{sub x}Ga{sub 1−x}N layer composition was varied from 15% to 25%. The crystalline quality, thickness and aluminum (Al) composition of AlGaN were determined using high resolution X-ray diffraction (HRXRD). The growth rate decreases on increasing Al composition. Reciprocal space mapping (RSM) was used to estimate the strain and relaxation between AlGaN and AlN. The optical properties of AlGaN layers were investigated by room temperature Photoluminescence (PL). The AlGaN peak shifts towards lower wavelength with Al composition. The surface morphology of AlGaN was studied by atomic force microscopy (AFM). Root mean square (RMS) roughness values were found to be increased in AlGaN layers with composition.

  17. ZnO-Based Transparent Thin-Film Transistors with MgO Gate Dielectric Grown by in-situ MOCVD

    NASA Astrophysics Data System (ADS)

    Zhao, Wang; Dong, Xin; Zhao, Long; Shi, Zhi-Feng; Wang, Jin; Wang, Hui; Xia, Xiao-Chuan; Chang, Yu-Chun; Zhang, Bao-Lin; Du, Guo-Tong

    2010-12-01

    ZnO transparent thin-film transistors with MgO gate dielectric were fabricated by in-situ metal organic chemical vapor deposition (MOCVD) technology. We used an uninterrupted growth method to simplify the fabrication steps and to avoid the unexpectable contaminating during epitaxy process. MgO layer is helpful to reduce the gate leakage current, as well as to achieve high transparency in visible light band, due to the wide band gap (7.7eV) and high dielectric constant (9.8). The XRD measurement indicates that the ZnO layer has high crystal quality. The field effect mobility and the on/off current ratio of the device is 2.69 cm2 V-1s-1 and ~ 1 × 104, respectively.

  18. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Growth and Characteristics of Epitaxial AlxGa1-xN by MOCVD

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Guo, Li-Wei; Chen, Yao; Xu, Pei-Qiang; Ding, Guo-Jian; Peng, Ming-Zeng; Jia, Hai-Qiang; Zhou, Jun-Ming; Chen, Hong

    2009-06-01

    AlxGa1-xN epilayers with a wide Al composition range (0.2 <= x <= 0.68) were grown on AlN/sapphire templates by low-pressure metalorganic chemical vapour deposition (LP-MOCVD). X-ray diffraction results reveal that both the (0002) and (10bar 15) full widths at half-maximum (FWHM) of the AlxGa1-xN epilayer decrease with increasing Al composition due to the smaller lattice mismatch to the AlN template. However, the surface morphology becomes rougher with increasing Al composition due to the weak migration ability of Al atoms. Low temperature photoluminescence (PL) spectra show pronounced near band edge (NBE) emission and the NBE FWHM becomes broader with increasing Al composition mainly caused by alloy disorder. Meanwhile, possible causes of the low energy peaks in the PL spectra are discussed.

  19. Control of carbon content in amorphous GeTe films deposited by plasma enhanced chemical vapor deposition (PE-MOCVD) for phase-change random access memory applications

    NASA Astrophysics Data System (ADS)

    Aoukar, M.; Szkutnik, P. D.; Jourde, D.; Pelissier, B.; Michallon, P.; Noé, P.; Vallée, C.

    2015-07-01

    Amorphous and smooth GeTe thin films are deposited on 200 mm silicon substrates by plasma enhanced—metal organic chemical vapor deposition (PE-MOCVD) using the commercial organometallic precursors TDMAGe and DIPTe as Ge and Te precursors, respectively. X-ray photoelectron spectroscopy (XPS) measurements show a stoichiometric composition of the deposited GeTe films but with high carbon contamination. Using information collected by Optical Emission Spectroscopy (OES) and XPS, the origin of carbon contamination is determined and the dissociation mechanisms of Ge and Te precursors in H2 + Ar plasma are proposed. As a result, carbon level is properly controlled by varying operating parameters such as plasma radio frequency power, pressure and H2 rate. Finally, GeTe films with carbon level as low as 5 at. % are obtained.

  20. The use of metalorganics in the preparation of semiconductor materials. VIII - Feasibility studies of the growth of Group III-Group V compounds of boron by MOCVD

    NASA Technical Reports Server (NTRS)

    Manasevit, H. M.; Hewitt, W. B.; Nelson, A. J.; Mason, A. R.

    1989-01-01

    The MOCVD growth of B-As and B-P films on Si, sapphire, and Si-on-sapphire substrates is described; in this process, trimethylborane (TMB) or triethylborane (TEB) is pyrolyzed in the presence of AsH3 or PH3 in an H2 atmosphere. The procedures employed are outlined, and the results are presented in graphs, tables, and micrographs. It is found that the growth rate of the primarily amorphous films is dependent on the TMB or TEB concentration but approximately constant for TEB and AsH3 at 550-900 C. The nominal compositions of films grown using TMB are given as B(12-16)As2 and B(1-1.3)P. Carbon impurities and significant stress, bowing, and crazing are observed in the films grown on Si substrates, with the highest carbon content in the films grown from TMB and PH3.