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  • 1
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact coaxial electron cyclotron resonance (ECR) plasma source is built for plasma deposition experiments. The ECR plasma is produced in a coaxial line configuration and hence the source is compact. The plasma parameters (plasma density and electron temperature) are measured using a Langmuir probe. The plasma parameters are mainly dependent on the center conductor (stub) dimensions of the coaxial line. The characterization of plasma for both conical and cylindrical stubs is carried out and it is found that the conical stub produces relatively denser and more stable plasma than the cylindrical stub. The typical plasma density and electron temperature are 3×1010 cm−3 and 5 eV, respectively, for argon plasma. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this ECR ion source, the possibility of maintaining the plasma by slow wave structures (SWS), helical coil, and slotted line antennas, in the region where wce, wpe (very-much-greater-than) wrf (wce, wpe, and wrf are electron cyclotron, plasma, and microwave frequencies, respectively) is exploited. The plasma parameters, plasma density, and electron temperature are maximized by coupling microwave (frequency: 2.45 GHz; power: 650 W) at two places in a magnetic mirror machine (mirror ratio Rm (approximately-equal-to) 1.45) to obtain higher beam current. Initially, the plasma is produced by coupling microwave to SWS at the mirror throat. The microwave is coupled by exciting the dominant slow wave field component of SWS, using an E-plane horn antenna. Then the plasma is brought to the region wce, wpe (very-much-greater-than) wrf at the mirror throat by increasing the magnetic field. Simultaneously, the ECR region is shifted from mirror throat to the center where second microwave coupling is done at the resonant region using another horn antenna. The characterization of plasma parameters are presented for both helical coil and slotted line antennas. Enhancement of plasma parameters are observed in the present scheme. Also, the SLA is found to produce better plasmas (ne ∼ 7 × 1012 cm−3 and Te ∼ 12 eV) than the helical coil and hence the SLA is chosen for the ion beam characterization. The extracted ion beam current density in the present scheme is ∼25 mA/cm2 at 2-kV extraction voltage.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This paper describes a new method of exciting slow wave structures (SWS) for obtaining high-density electron cyclotron resonance plasmas. The electric field component corresponding to the slow wave mode (SWM) of SWS is excited by an E-plane horn antenna. The special features of the microwave transmission line are the stable tuning for a given antenna and no requirement for water cooling on any of the components. Two types of SWS, a helical coil and a slotted line antenna, are studied, and the experiments are carried out in nitrogen and argon. The plasma producing capability is examined for these systems in the region wce,wpe(approximately-greater-than)wrf, where wce, wpe, and wrf correspond to electron cyclotron, plasma, and microwave frequencies, respectively. A high-density, large-diameter plasma (n0∼5×1011 cm−3; diameter ∼8.0 cm) could be obtained and the plasma could be maintained in the region 1≤wce/wrf≤2.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 1297-1315 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A detailed mechanism and corresponding mathematical model is suggested for bulk PVC production. The model is more detailed and general than earlier models and is consistent with reported experimental data as well as new experimental evidence presented here. Equations are presented and computations performed showing the evolution of the particle size distribution of the polymer beads. The predicted particle size distributions are in reasonable agreement with the limited experimental data available.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric permittivity and loss of poly(vinyl pyrrolidone), molecular weight 40,000, containing 40% (by weight) water have been measured over the temperature range 77-325 K and frequency range 12 Hz to 0.1 MHz. A prominent relaxation due to rotational diffusion of water molecules in a hydrogen-bonded structure occurs at T 〈 Tg (237 K). The half-width of the dipolar relaxation spectra is 2.27 decades and is temperature independent, which is strikingly different from the corresponding features of pure polymers. It is concluded that H-bonded amorphous solid water persists in the glassy polymer matrix and that the H-bonded structure contains the pyrrolidone side groups of the randomly oriented chain. The relaxation peak at T near Tg is masked by a large dc conductivity which, when expressed in terms of electric modulus, has a spectrum of half-width 1.37 instead of 1.14 decades expected for dc conductivity alone. The contribution from dipolar reorientation in the glass-rubber range of the PVP-H2O solution is smaller than that in its sub-Tg relaxation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 8 (1979), S. 11-13 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An X-ray fluorescence method for the measurement of film and coating thickness has been described for use in situations where standard foils of the same material are not available for comparison. The method is based on the measurement of combined mass absorption coefficient of the coating element at the excitation and at the fluorescent energies using thin samples of a compound in which the coating element is present and then calculating the coating thickness using the fluorescence equation. The paper describes the theoretical approach and presents the result of the measurement of certain film and coating thicknesses which support the theoretical considerations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High frequency ultrasonic waves of frequency 1 Mc/s. have been employed to study the decolourization of dilute aqueous solution of crystal violet. The process is irreversible and the kinetic study shows it to be unimolecular one. The deaeration of the solution by nitrogen does not affect the rate of the decolourization. The addition of certain substances such as alcohol, acetone, ether, glycerine, dioxan and allylthiourea inhibits the decolourization to a considerable extent. Oxidation and subsequent destruction of the dye molecule has been found to be the cause of the fading of the dye solution.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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