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  • 2000-2004  (8)
  • 1990-1994  (10)
  • 1965-1969  (8)
  • 1955-1959  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Development of a steady-state microwave ion source with large spherical electrodes for geometrical focusing : The 8th international conference on ion sources (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 1144-1147 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A steady-state electron cyclotron resonance ion source with large spherical electrodes has been developed to study the plasma wall interaction, erosion mechanism, and hydrogen retention of first wall materials in a nuclear fusion reactor. Discharge characteristics of the ion source were studied in terms of microwave power, magnetic field configuration, and gas (H2) pressure. Ion saturation current density Jis of about 21 mA/cm2 near the electrodes (target value is 20 mA/cm2) was achieved with microwave power of 3.0 kW and magnetic field of 2.3 kG at an optimal gas pressure. The measurement of Jis was made by a Langmuir probe. It was found that the dependence of ion saturation current density on the magnetic field was different between high (〉5 mTorr) and low (〈5 mTorr) pressure. The change of the gas inlet position from the center of the plasma production chamber to near the microwave input window gave higher ion saturation current density. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150410
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  • 2
    Electronic Resource
    Electronic Resource
    Theory of formation of the ionosphere (1966)
    Springer
    Space science reviews 5 (1966), S. 3-56 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Current knowledge about the solar radiation and absorption and ionization cross sections of atmospheric gases is reviewed. Next the main observed features of ionospheric layers are summarized. Using CIRA 1965 model atmospheres the heights of the peak of the ionization rate are calculated for a number of solar emission lines and it is made clear which of these lines are responsible for the formation of E and F1 layers. The mechanism of electron removal in the F and upper E regions as well as in the lower regions is considered, and the mechanism of formation and some behaviours of each ionospheric layer is discussed. In particular, the equatorial F2 layer is briefly considered. Discrepancies are pointed out between the values of the recombination coefficient and the rate constant for ion-atom interchange reaction obtained from ionospheric observations and from laboratory experiments. Inconsistency of the values of the intensity of solar radiation measured by rocket techniques and inferred from ionospheric considerations is also noted. Some evidence is presented suggesting that corpuscular radiation may be responsible for part of the ionization in the ionosphere even in temperate latitudes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00179214
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  • 3
    Electronic Resource
    Electronic Resource
    Fluorescence microscopic observations of catecholamines in cultures of the sympathetic chains (1967)
    Springer
    Cell & tissue research 80 (1967), S. 345-352 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A histochemical technique for the demonstration of catecholamines developed by Falck et al. has been successfully applied to the sympathetic chains of rats and mice maintained in vitro. Catecholamines were localized in the nerve fibers, showing identical green fluorescence as in tissue sections of healthy rats. The cultures 8 days in vitro exhibited positive reaction in a few terminals, whereas sister cultures 1 month in vitro showed strong fluorescence reaction in thicker proximal axons and networks of nerve fibers as well. Reactivity of neuron somas became positive after 1 month of cultivation. Application of reserpine in amount of 0.00025 mg/ml for 2 hours resulted in complete disappearance of fluorescence. Furthermore, cultures of spinal ganglia from fetal rat produced no fluorescence reaction with this technique. Therefore, the reaction is specific for sympathetic nervous tissue and reliable for the differentiation of sympathetic neurons from other types of nerve cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339327
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  • 4
    Electronic Resource
    Electronic Resource
    Molecular orbital theory of reactivity in radical polymerization. Part II (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 20 (1956), S. 537-550 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several problems in the process of radical polymerization, e.g., the relation between the chemical structure of vinyl monomer and its chemical reactivity, the prevalence of head-to-tail configuration, the reactivity of initiator radicals, the alternation tendency in heteropolymerization, and the relative ease of coupling in several cases of homopolymerization, are treated by the theory previously proposed by the present authors, in which reactivity is represented by the magnitude of stabilization energy due to π conjugation between a monomer and a radical in the transition state. In addition, a brief discussion on the existing theories of reactivity and some applications of Hush's method to the problem of termination are presented. The agreement between results of calculation and experiment is shown to be almost statisfactory.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.120209612
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  • 5
    Electronic Resource
    Electronic Resource
    Molecular orbital theory of reactivity in ionic polymerizations (1957)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 26 (1957), S. 311-321 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stabilization energy due to the conjugation taking place between a monomer and an ion in the transition state is calculated by the LCAO perturbation theory, in the same way in which the reactivity in radical copolymerization has previously been treated. In terms of this stabilization energy, the reactivity ratios of several monomer pairs in ionic copolymerization are satisfactorily interpreted. It is noted that, by the present method, both the radical and ionic copolymerization can be treated in a unified manner, whereas it is difficult in existing empirical methods. The positions of attack in polymer ions as well as in monomers, which are predicted by the frontier electron densities, are shown to agree well with experimental facts. The relative reactivities of vinyl monomers in ionic homopolymerization is also explained successfully by the magnitude of the localization energy computed by the LCAO method.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1957.1202611406
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical considerations on the mechanism of stereospecific cationic polymerization in homogeneous systems (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 39 (1959), S. 487-492 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theoretical interpretation of the mechanism of stereospecific cationic polymerization in a homogeneous system at low temperature is given. The existance of a counterion in the vicinity of a charged carbon atom of a growing polymer ion is assumed and a repulsive interaction is considered to be between the substituent of the attacking monomer and that of the polymer. The most probable geometrical conformation of a monomer and a polymer ion in the transition state is determined by the magnitude of stabilization due to the overlap between atomic orbitals of ion and monomer. Our experimental results can be explained satisfactorily by this mechanism.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1203913540
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  • 7
    Electronic Resource
    Electronic Resource
    13C NMR spectra and reactivity in cationic polymerization of vinyl and alkenyl ethers (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 7 (1969), S. 23-26 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.110070105
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  • 8
    Electronic Resource
    Electronic Resource
    Solvent effects in anionic copolymerization. II. Molecular orbital treatment for the pair: Styrene-methylstyrene (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2215-2222 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A model is proposed for the transition state of the anionic copolymerization of styrene and p-methylstyrene in hydrocarbon solvent with lithium counterion. An LCAO-MO treatment which considers the effect of the positive counterion on the negative chain end is used to calculate the electrostatic and the π electron resonance contributions to the activation energies of the four propagation reactions. The electron contributions to the activation energies are also calculated for the propagation reactions of free ions, i.e., in the absence of a counterion. The previously determined rate constants in benzene and tetrahydrofuran are then compared with the results of these calculations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030610
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  • 9
    Electronic Resource
    Electronic Resource
    Cationic polymerization of α,β-disubstituted olefins. Part 12. Theoretical consideration of the reactivities of vinyl ethers and β-substituted vinyl ethers (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 3129-3141 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To elucidate the propagation mechanism in the cationic polymerization of vinyl ethers and β-substituted vinyl ethers, the electron distribution in these monomers was computed by the extended Hückel method. Propylene and styrene derivatives were also studied in comparison with the vinyl ether derivatives. Attempts were made to explain the experimental results by various calculated reactivity indices. With the unsaturated hydrocarbons, the reactivity indices on the β-carbon parallel with the relative reactivity in the cationic polymerization or oligomerization. This agreement suggests that the transition state for the rate-determining step of the propagation reaction is represented by a model in which the carbonium ion interacts with the β-carbon of a monomer. On the other hand, the effect of β-alkyl or alkoxyl groups on the reactivity of vinyl ethers could not be explained by the model in which the carbonium ion interacts with an olefinic carbon or an ether oxygen, or both with two atoms. The following model was proposed on the basis of the electronic stabilization energy due to the de- localization from the occupied orbital of a monomer to the vacant orbital of a carbonium ion. This model can explain reasonably the relative reactivity of vinyl ethers and β-substituted vinyl ethers observed in the cationic copolymerization catalyzed by BF3·O(C2H5)2.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.150071109
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  • 10
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    Development of a steady-state microwave ion source with large spherical electrodes for geometrical focusing (2000)
    American Institute of Physics
    Details
    Publication Date: 2000-02-01
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Published by American Institute of Physics
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