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  • 1
    Electronic Resource
    Electronic Resource
    Influence of the shock wave pressure gradient in α-Fe irradiated by a high-power ion beam on the occurence of a microhardness maximum at large depths (1998)
    Springer
    Technical physics letters 24 (1998), S. 102-104 
    Details
    ISSN: 1090-6533
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The defect structure and microhardness of α-Fe irradiated by a high-power pulsed beam have been studied using positron annihilation, transmission electron spectroscopy, and a nanoindenter, and results are presented. It is shown that in α-Fe exposed to a high-power pulsed beam, the pressure gradient and depth of formation of the shock wave front influence the formation and location of the dislocation density maximum and the microhardness maximum in the modified layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1262011
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  • 2
    Electronic Resource
    Electronic Resource
    Second-harmonic generation in the interior of an isotropic medium with quadratic nonlinearity by a focused inhomogeneously polarized pump beam (1998)
    Springer
    Journal of experimental and theoretical physics 86 (1998), S. 687-695 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper presents a theoretical study of second-harmonic generation (SHG) by a focused pump beam in the interior of an isotropic medium, experimentally observed earlier. It shows that the spatial dispersion of the quadratic optical response of the substance can be responsible for this nonlinear process even when a macroscopic inversion center is present in the medium. It is established that this effect, which is impossible in the plane-wave approximation, also does not occur when a Gaussian pump beam with uniform distribution of the polarization state of the wave field over the cross section is used, but that the presence in the pump beam of higher transverse modes with polarization different from the fundamental mode can cause an SHG signal to appear. The conditions for a wave to appear at the doubled frequency are found, analytical dependences for its electric field and total power on the propagation coordinate, the degree of focusing, and the other parameters of the problem are obtained, and the requirements on the optimum experimental geometry are formulated. The dependence of the signal-beam power on the wavevector detuning is studied, and it is shown that interference effects can cause the wave at the second harmonic to disappear when a normal dispersion law is obeyed in the region between the fundamental and doubled frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558527
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of a shock-wave pressure gradient on the appearance of a microhardness maximum in α-Fe irradiated by a high-power ion beam (1998)
    Springer
    Technical physics letters 24 (1998), S. 819-821 
    Details
    ISSN: 1090-6533
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The results of research on the defect structure and microhardness in α-Fe irradiated by a pulsed high-power ion beam are presented. The results are obtained with the use of positron annihilation, electron microscopy, and a nanoindenter. It is shown that the pressure gradient and the depth of formation of the shock wave front in α-Fe irradiated by a high-power ion beam have an influence on the formation and location of the maximum of the dislocation density and microhardness in the modified layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1262279
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  • 4
    Electronic Resource
    Electronic Resource
    Experimental studies of a microsecond plasma opening switch in the positive polarity regime with inductive load/extraction ion diode (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 5772-5782 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Systematic studies of the microsecond plasma opening switch (MPOS) operation in the positive polarity of its inner electrode with an inductive load/B-applied ion diode of the extraction type at a level of 0.3 TW of dissipated power were performed at the DOUBLE generator (300 kA, 480 kV, 1 μs). The detailed measurements of ion flow parameters in the conductive phase of the MPOS showed the considerable enhancement of the ion current amplitude over the thermal flow limit (3–10 times) which is coupled with a significant decrease of electron conductivity in the MPOS across its self-magnetic field. The positive polarity MPOS operation proved to be more critical to the stored current amplitudes and geometry of the electrodes in comparison with the negative polarity case. This fact resulted in limitations of satisfactory performance of the MPOS involving short high-voltage pulse duration, low stored current amplitudes, and a narrow region of acceptable electrode diameters. The variation of the diode anode-cathode (AC) gap provided a sensitive control of the MPOS + magnetically insulated diode (MID) system, which displayed very strong coupling, resulting in clamping of the output voltage in a wide region of diode impedances. The early long-duration (〈300 ns) high-voltage (50–200 kV) prepulse improves plasma production at the anode of the MID prior to the application of the main pulse. The optimal performance of the MPOS+MID system was realized at the level of ZMPOS/ZMID = 2.5. The energy of the extracted high-power ion beam made up 3.5 kJ, its power being 120 GW with 40% efficiency of energy transfer from MPOS to the MID.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350471
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  • 5
    Electronic Resource
    Electronic Resource
    Spatial correlation function of the intensity in multiple scattering (1984)
    Springer
    Journal of Russian laser research 5 (1984), S. 102-104 
    Details
    ISSN: 1573-8760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01120533
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  • 6
    Electronic Resource
    Electronic Resource
    Some aspects of the DNA hypochromic effect theory (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 119-132 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The expressions for the polymer absorption band hypochromism and oscillator strength are studied in frames of the first-order perturbation theory. The physically justified approximations for a polymer hypochromism calculation are indicated. The uniform interpretation of the effect origin is given independently on the approximation used. In frames of the perturbation theory the DNA hypochromism formula is obtained, from which the known experimental dependences of hypochromism on chain length and polymer helicity degree follows directly. The analytic expression of the DNA hypochromism dependence on AT pairs content is obtained. It is established that in most cases for natural DNA the nucleotide sequence does not influence in practice the value of the hypochromic effect.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160115
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  • 7
    Electronic Resource
    Electronic Resource
    Quantum-mechanical study of the hypochromic effect in polynucleotides. Intra- and interstrand interaction contributions (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1205-1212 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first uv absorption band hypochromism of poly(dA) · poly(dT), poly(dG) · poly(dC), poly(dA), poly(dT), poly(dG), and poly(dC) is calculated with the help of perturbation theory on the basis of monomer characteristics computed by the Pariser-Parr-Pople method taking into account all singly excited configurations. The theoretical results obtained are in good agreement with experimental values of hypochromism. The origin of the hypochromic effect in the double-stranded polynucleotides is investigated. It is shown that intrastrand interactions between the bases make the main contribution to hypochromism (60-76%), while the contribution of the Watson-Crick-pair formation is small (2-12%). The essential part of hypochromism (22-28%) is due to the interstrand interactions between the bases that are not coupled by hydrogen bonds. The discussion of the experimental data shows that the present theoretical investigation could serve as a basis for the correct treatment of experimental data.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140609
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