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  • 11
    Electronic Resource
    Electronic Resource
    Methane conversion by an air microwave plasma (1995)
    Springer
    Plasma chemistry and plasma processing 15 (1995), S. 87-107 
    Details
    ISSN: 1572-8986
    Keywords: Air microwave plasma ; methane activation ; C2 hydrocarbon formation ; carbon monoxide formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Activation of methane is carried out by means of an air microwave plasma (2.45 GHz). The experiments cover the absorbed microwave power range 350–650 W (20–50 W cm3 with 17–62%, of methane in the gas mixture, with pressures of 10–66 mbar and flow rates of 140‐700 ml min1. Methane, dioxygen, and dinitrogen consumptions as well as C2 hydrocarbons, carbon monoxide, and dihydrogen yields are analyzed hr gas chromatography. The distance of methane addition from the end of the discharge plays an important role in the composition and the concentration of the products obtained. This distance mainly determines the energy concentrated in the active species of the plasma when they react with methane. A kinetic mechanism jar the activation and decay of inethane and for the formation of C2 hydrocarbons and carbon monoxide is discussed based on the experimental results and kinetic data in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01596683
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  • 12
    Electronic Resource
    Electronic Resource
    Concentrations of Active Species in the Flowing Afterglow of a Nitrogen Microwave Plasma (1998)
    Springer
    Plasma chemistry and plasma processing 18 (1998), S. 447-460 
    Details
    ISSN: 1572-8986
    Keywords: Nitrogen afterglow ; microwave discharge ; nitrogen atom concentration ; metastable nitrogen molecule concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Measurements of nitrogen atom density, by means of NO chemical titration, along with an evaluation of the densities of some excited species N 2 (B, v=11), N 2 (B, v=2), N 2 (C, v=0), and N 2 + (B,v=0), by means of a spectroscopic study of some bands of dinitrogen, are achieved along the flowing afterglow of a dinitrogen microwave plasma (2450 MHz) for several pressures. The concentrations obtained are in the following range: [N]∼10 +15 , [N 2 (B, 2)]∼10 +9 –10 +10 , [N 2 (B, 11)]∼10 +8 –10 +9 , [N 2 (C, 0)]∼10 +6 –10 +7 , [N 2 + (B,0)]∼10 +6 -10 +8 (cm-3). From a kinetic study of the formation and decay of excited and charged species, an estimation of N 2 (A, v), N 2 (X, v, and N 2 + (X) densities can be derived: [N 2 (A, v)]∼10 +12 , [N 2 (X, v≥6)]∼10 +15 –10 +16 , [N 2 (X, v≥12)]∼10 +14 –10 +15 , [N 2 + (X)]∼10 +10 (cm -3 ).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021855131761
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  • 13
    Electronic Resource
    Electronic Resource
    Comparison of latex agglutination and counterimmunoelectrophoresis in the diagnosis of acuteStreptococcus pneumoniae infections (1983)
    Springer
    European journal of clinical microbiology & infectious diseases 2 (1983), S. 534-540 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ability of latex agglutination (Slidex Pneumokit) and counterimmunoelectrophoresis to detectStreptococcus pneumoniae antigen in body fluids was evaluated. The patients were classified as having provenStreptococcus pneumoniae infection, suspectedStreptococcus pneumoniae infection, acute superinfection of chronic bronchitis or non-pneumoccal respiratory infection. Sixtytwo non-pneumococcal meningitis patients were also included in the study. Latex agglutination and counterimmunoelectrophoresis tests were performed on serum, urine and cerebrospinal fluid specimens when indicated and repeated each week until the patient was discharged. Latex agglutination was done on samples boiled for 10 min. In vitro sensitivity of counterimmuno-electrophoresis and latex agglutination were 10 and 1 ng/ml respectively for type three antigen. In pulmonary disease (proven and suspectedStreptococcus pneumoniae infection) counterimmunoelectrophoresis and latex agglutination had a clinical sensitivity of 72.9 and 87.5 % respectively, a specificity of 96.3 and 92.6 %, a predictive value for a positive test of 97.2 and 95.4 % and for a negative test of 66.6 and 80.6 %. Latex agglutination may offer an alternative to counterimmunoelectrophoresis in the rapid diagnosis ofStreptococcus pneumoniae infections since it is easier to perform and gives a reliable result within 15 min.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02016561
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  • 14
    Electronic Resource
    Electronic Resource
    A kinetic study of methane conversion by a dinitrogen microwave plasma (1994)
    Springer
    Plasma chemistry and plasma processing 14 (1994), S. 229-249 
    Details
    ISSN: 1572-8986
    Keywords: Nitrogen microwave plasma ; methane conversion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Conversion of CH4 with a N2 microwave plasma (2.45 GHz) is studied. The experiments cover the absorbed microwave power range 300–700 W with 17–62% of methane in the gas mixture, with pressures of 10–40 mbar and flow rates of 140–650 ml· min−1. The yields of C2 hydrocarbons and dihydrogen are analyzed by gas chromatography. The distance of methane addition downstream of the plasma plays an important role on the composition and the concentration of the products obtained. This distance mainly determines the energy concentrated in the active species of the plasma when they react with methane. Different behaviors for acetylene formation, on the one hand, and for ethane and ethene formation, on the other hand, have been observed, and this finding allows us to propose a kinetic mechanism for the decay of methane and for the formation of C2 hydrocarbons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447080
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  • 15
    Electronic Resource
    Electronic Resource
    Surface oxidation by microwave-induced plasma of candidate composite materials for space shuttle protection (1990)
    Springer
    Journal of materials science 25 (1990), S. 4113-4119 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Oxidation resistance of composite materials (SiC/SiC, C/SiC and C/C) which can be used to protect shuttles is studied in oxygen microwave-induced plasmas (MIP). These plasmas contain the same energetic species (electrons, ions, radicals, excited atoms or molecules) as those produced by the shock wave resulting from re-entry into the atmosphere. The plasma is sustained in a silica tube located in a resonant cavity and microwave energy is supplied by a generator operating at 2450 MHz with variable power from 15 to 1000W. Experiments are conducted at pressures from 100 to 1000 Pa with temperature ranging from 1100 to 1300 °C. The atomic oxygen flow rate is about 6.1019 at sec−1 cm−2. The wafers are exposed to the plasma for 10 to 25 h for periods of 15 or 30min. Kinetic behaviour of the material is studied by gravimetry and surface characteristic modifications are analysed by BET Krypton isotherms at 77 K and electron spectroscopy for chemical analysis (ESCA). Gravimetric results, measurements of specific surface area by krypton adsorption and ESCA analysis show that the samples of SiC/SiC and C/SiC are quite resistant to the oxygen plasma even after 25 h exposure. The mass loss is small and the specific surface area (BET) increases but is always lower than 1 m2 g−1. ESCA analysis shows that the surface evolves by change of the superficial silicon carbide into silica. The C/C samples behave quite differently: without any protection they disappear in less than 5 min. With an antioxidant protective layer, this material can be oxidation resistant. The BET and ESCA measurements show that the attack leads to a sintering of the silica which gathers on the fibres, reducing the protection of the matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582490
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