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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1749-1752 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact 5-cm-diam multipolar electron cyclotron resonance (ECR) ion source is characterized. The source is experimentally studied with no grids using argon gas with 50–250 W of 2.45-GHz microwave input power. Using a microcoaxial probe it was confirmed that the exciting electromagnetic fields within the resonant cavity were indeed TE111, as expected from the critical cavity dimensions. Double Langmuir probe measurements indicate high densities of about (4–5)×1011/cm3 near the source, and 5 cm downstream from the source output the densities become very uniform with a value of about 5×1010/cm3 over a 10-cm diameter. Electron energy distribution functions (EEDF) were measured using a single Langmuir probe. Average electron energies were seen to be about 8–10 eV with an energy distribution function falling between a Maxwellian and a Druyvesteyn distribution. Ion energy distribution functions (IEDF) were measured with a multigrid energy analyzer. It was seen that the distribution functions were narrow and peaked [with a full width half maximum (FWHM) of about 5 eV] except under certain conditions. Above 200-W input power, and also below about 0.5 mTorr there is significant broadening of the ion distribution function. It is speculated that the former may be caused by gas heating, and the latter may be caused by the presence of Ar+2 ions. With its high current densities ((approximately-greater-than)10 mA/cm2) and low average ion energies (〈40 eV), it is expected that this ion/plasma source will be very useful in many etching and deposition applications.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1310-1310 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact 5-cm-diam multipolar electron cyclotron resonance (ECR) ion source is characterized. The source is experimentally studied with no grids using argon gas with 50–250 W of 2.45-GHz microwave input power. Using a microcoaxial probe it was confirmed that the exciting electromagnetic fields within the resonant cavity were indeed TE111, as expected from the critical cavity dimensions. Double Langmuir probe measurements indicate high densities of about (4–5)×1011/cm3 near the source, and 5 cm downstream from the source output the densities become very uniform with a value of about 5×1010/cm3 over a 10-cm diameter. Electron energy distribution functions (EEDFs) were measured using a single Langmuir probe. Average electron energies were seen to be about 8–10 eV with an energy distribution function falling between a Maxwellian and a Druyvesteyn distribution. Ion energy distribution functions (IEDF) were measured with a multigrid energy analyzer. It was seen that the distribution functions were narrow and peaked [with a full width half maximum (FWHM) of about 5 eV] except under certain conditions. Above 200-W input power, and also below about 0.5 mTorr there is significant broadening of the ion distribution function. It is speculated that the former may be caused by gas heating, and the latter may be caused by the presence of Ar+2 ions. With its high current densities ((approximately-greater-than)10 mA/cm2) and low average ion energies (〈40 eV), it is expected that this ion/plasma source will be very useful in many etching and deposition applications.
    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: The 2.45 GHz plasma source is a multicusp electron cyclotron resonance source with a tuned single mode microwave cavity. This is a bright plasma source with a well characterized operating mode and plasma parameters [A. K. Srivastava, et al., Rev. Sci. Instrum. 63, 2556 (1992); A. K. Srivastava and J. Asmussen, J. Vac. Sci. Technol. A 11, 1307 (1993)]. The superconducting electron cyclotron resonance (SCECR) is a fully superconducting, hexapole stabilized tandem mirror ion source with a multimode microwave cavity. It is a high charge state ion source with extensive beam diagnostics [T. A. Antaya, Nucl. Instrum. Methods B 40/41, 1024 (1989)]. The coupling of these two sources permits a number of fundamental studies important to both classes of ion sources. The 2.4 GHz plasma source will be used to study the effects of ion or electron (or both) density enhancement on the charge state distribution, total extracted current, and ion energy distributions of the SCECR. The SCECR in turn will be used as a test stand to measure directly the ion distribution and beam characteristics of the 2.45 GHz plasma source. The first results with this hybrid ion source will be presented at this conference.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The electromagnetic excitation of a discharge inside a microwave plasma source has been numerically modeled in the time domain. The source is a cylindrical, single-mode microwave-excited cavity. The time-varying electromagnetic fields inside the resonant cavity, both inside and outside the discharge region, are obtained by applying a finite-difference time-domain method to solve Maxwell's equations. The electromagnetic properties of the discharge load are described using a conductivity model. The spatial electric field patterns, natural frequencies, stored energy, and quality factor of a plasma-loaded, microwave-resonant cavity are simulated. Additionally, the simulated results for a simplified plasma source structure are compared to a known analytical solution to verify the simulation technique.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1761-1765 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The electromagnetic excitation of a discharge inside a microwave plasma source has been numerically modeled in the time domain. The source is a cylindrical, single-mode microwave-excited cavity. The time-varying electromagnetic fields inside the resonant cavity, both inside and outside the discharge region, are obtained by applying a finite-difference time-domain method to solve Maxwell's equations. The electromagnetic properties of the discharge load are described using a conductivity model. The spatial electric field patterns, natural frequencies, stored energy, and quality factor of a plasma-loaded, microwave-resonant cavity are simulated. Additionally, the simulated results for a simplified plasma source structure are compared to a known analytical solution to verify the simulation technique.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Veterinary research communications 18 (1994), S. 313-318 
    ISSN: 1573-7446
    Keywords: calves ; cefotaxime ; cephalosporin ; dose ; intramuscular ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pharmacokinetics, penetration into erythrocytes and plasma protein binding of cefotaxime were investigated in cross-bred calves. Following a single intramuscular dose of cefotaxime (10 mg/kg), the absorption half-life and elimination half-life were 0.13±0.03 h and 2.97±0.72 h, respectively. The apparent volume of distribution and total body clearance were 3.28±0.72 L/kg and 0.78±0.08 L/kg per h, respectively. The extent of penetration into erythrocytes was 24–40% of the total blood concentration. Cefotaxime was bound to plasma proteins of calves to the extent of 25.5–33.6%. A satisfactory intramuscular dosage regimen for cefotaxime in calves would be 11 mg/kg followed by 10 mg/kg at 7 h intervals.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 219 (1994), S. 1-10 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Umsetzung von Chromacrylat mit Bisphenol A und einem Überschuß Epichlorhydrin wurden neuartige Epoxid-Harze hergestellt. Epoxy-Äquivalentgewicht, Gehalt an Hydroxygruppen und hydrolysierbarem Chlor sowie die Viskosität wurden bestimmt, und die Harze wurden mittels IR- und 1H-NMR-Spektroskopie charakterisiert. Die thermischen Eigenschaften der bei 30°C für 24 h mit Ciba Geigy HY 850 (aliphatisches Amin) gehärteten Harze wurden gemessen. Die Harze besitzen eine gute thermische und chemische Stabilität und eine gute elektrische Leitfähigkeit. Die Reaktion verläuft nach erster Ordnung; die Aktivierungsenergie beträgt 47 kJ mol-1 bzw. 34 kJ mol-1 mit bzw. ohne Chromacrylat. Aus spektroskopischen Untersuchungen wird geschlossen, daß das Chrom mit Bisphenol A einen Komplex bildet, der die Epoxidierung beschleunigt.
    Notes: Novel epoxy resins containing chromium acrylate have been synthesized by reacting chromium acrylate with bisphenol-A and excess epichlorohydrin. The quantities such as epoxy equivalent weight, hydroxy content, hydrolyzable chlorine content and viscosity have been determined. The resins have been characterized by IR and 1H NMR spectroscopy. The cured resins were evaluated for thermal properties. The curing of resins was carried out with Ciba Geigy HY 850 (aliphatic amine adduct) at 30°C for 24 h. The cured resins have excellent thermal and chemical resistance, in addition to an excellent electrical conductivity. The reaction follows first order kinetics with an activation energy of 47 kJ mol-1 and 34 kJ mol-1 in the presence and absence of chromium acrylate, respectively. The chromium forms a complex with bisphenol-A, as indicated by spectroscopic studies, which increases epoxidation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 34 (1994), S. 528-531 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Terpolymerization was investigated by dilatometry for zincacrylate (ZnA2), acrylonitrile (AN), and styrene (St), radically initiated by a As2S3-styrene complex (I) in dimethyl sulphoxide (DMSO), at 90 ± 0.1°C for 1 h under inert atmosphere. The system follows non-ideal kinetics, due to primary radical termination as well as a degradative chain transfer reaction. The kinetic expression for the system is Rpα(I)0.27 (St)0.31 (AN) 0.22[ZnA2]0.12. The value for the activation energy and kp2/kt are 55 kJ mol-1 and 1.87 × 10-7 1 mol-1 s-1 respectively. The terpolymer has been characterized by IR and NMR spectroscopy. The thermal stability and solubility of the terpolymer have also been studied.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    World journal of microbiology and biotechnology 10 (1994), S. 299-302 
    ISSN: 1573-0972
    Keywords: Ammonia ; cyanobacterium ; Cycas ; Nostoc cycadae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Nostoc cycadae isolated from the host Cycas revoluta grew well in medium devoid of combined nitrogen but maximum growth was in medium containing nitrate (4.1 μg chlorophyll a ml-1). Aerated coralloid roots in the dark produced more NH3 when treated with l-methionine-dl-sulphoximine (MSO), an inhibitor of glutamine synthetase. With cultured N. cycadae and freshly isolated N. cycadae, NH3 production was enhanced by adding a host-tissue extract in the light or in the dark, whereas it was decreased by adding MSO. Nitrogenase activity was four times higher in coralloid root than in the cultured endophyte N. cycadae. The host-tissue extract may inhibit NH3 assimilatory pathways, thus inducing production of NH3 that can be utilized by the host itself.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 105-109 
    ISSN: 0959-8103
    Keywords: Zinc acrylate ; acrylonitrile ; As2S3-styrene complex ; copolymerization ; dilatometry ; kinetics ; 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: Radical copolymerization of zinc acrylate (ZnA2) with acrylonitrile (AN), initiated by As2S3-styrene complex(I), in dimethyl Sulphoxide (DMSO) at 90 ± 0.1°C for 1.0h under inert atmosphere, yields non-alternating copolymers. The kinetic expression is Rp ∝ [I]0.33 [ZnA2]0.25 [AN]0.44, i.e. the system follows non-ideal kinetics, which is due to primary radical termination as well as degradative chain transfer reactions. The values for activation energy (E) and k2p/kt are 128kJ mol-1 and 8.57 × 10-7 litre mol-1 s-1, respectively. Thermal stability, solubility in different solvents, and IR and NMR spectra have been evaluated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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