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1.
C. Czeranowsky V. M. Baev G. Huber P. A. Khandokhin Ya. I. Khanin I. V. Koryukin E. Yu. Shirokov 《Radiophysics and Quantum Electronics》2004,47(10-11):723-728
Experimental study of low-frequency dynamics of an intracavity frequency-doubled Nd:YAG laser demonstrates the influence of the interaction of orthogonally polarized modes, participating in frequency doubling (type II phase matching), on the stability of the laser output. At a sufficiently low pump rate and low conversion efficiency, the laser shows stable operation with a low noise level at the frequencies of relaxation oscillations. At a high pump power and/or a high conversion efficiency, the laser emission becomes unstable as a result of Hopf bifurcation at the frequencies of relaxation oscillations that are responsible for the anti-phase polarization dynamics of the laser. 相似文献
2.
A generalized inverse problem for the identification of the absorption coefficient for a hyperbolic system is considered. The well-posedness of the problem is examined. It is proved that the regular part of the solution is an L 2 function, which reduces the inverse problem to minimizing the error functional. The gradient of the functional is determined in explicit form from the adjoint problem, and approximate formulas for its calculation are derived. A regularization algorithm for the solution of the inverse problem is considered. Numerical results obtained for various excitation sources are displayed. 相似文献
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New possibilities are demonstrated for eliminating uncompensated Doppler broadening in different types of nonlinear optical
processes by means of atomic coherence effects in strong electromagnetic fields are demonstrated.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 12, 964–968 (25 June 1998) 相似文献
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The absorption of ammonia, sulfur dioxide, and carbon dioxide by water and aqueous solutions in rotating permeable media, a cellular porous disk, and a set of spaced-apart thin disks has been considered. The efficiency of cleaning air to remove these impurities is determined, and their anomalously high solubility (higher than equilibrium value) has been discovered. The results demonstrate the feasibility of designing cheap efficient rotor-type absorbers to clean gases of harmful impurities. 相似文献
7.
Using a series of mathematical models based on the closed Karman-Howarth equation, the numerical modeling of the dynamics of homogeneous isotropic turbulence was carried out. Computational results agree with known experimental data. Mathematical models are compared. 相似文献
8.
L. V. Baev V. N. Solodovnikov 《Journal of Applied Mechanics and Technical Physics》2004,45(6):860-870
The problem of spherically symmetric, gravitational compression of an isotropic hyperelastic layered sphere which modeling the region of the Earth below the Mohorovii boundary is solved. The known mechanical characteristics of the Earth in the compressed state are used to find its characteristics in the unstrained state obtained by adiabatic or isothermal stress relief. The stress state differs significantly from the state of purely hydrostatic compression. The minimum bulk compression and maximum radial tension occur not on the boundary of the sphere but in depth at certain distances from the boundary. 相似文献
9.
V. M. Baev I. N. Sarkisov É. A. Sviridenkov A. F. Suchkov 《Journal of Russian Laser Research》1989,10(1):61-85
The main features of broadband intracavity laser spectroscopy (ILS), the most sensitive technique of absorption-spectrum measurements, is investigated. The factors that limit the sensitivity of the ILS method are studied, and the conditions for reaching its maximum sensitivity are formulated. The main practical applications of the ILS method are described, such as detection of weak absorption spectra and measurements of low gas concentrations, registration of amplification spectra and of the spectral distribution of external radiation, measurement of the cross sections for nonlinear processes, investigation of transient processes in an electric discharge, and investigation of the kinetics of multistage chemical reactions.Translated from Preprint No. 187 of the Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1988. 相似文献
10.
B. Löhden S. Kuznetsova K. Sengstock V. M. Baev A. Goldman S. Cheskis B. Pálsdóttir 《Applied physics. B, Lasers and optics》2011,102(2):331-344
Intracavity absorption spectroscopy with a broadband Er3+-doped fiber laser is applied for the measurements of several molecular species revealing quantitative information about the
gas concentration, temperature and chemical reactions in flames. The spectral range of measurements extends from 6200 cm−1 to 6550 cm−1 with the proper choice of the fiber length and by moving an intracavity lens. With a pulsed laser applied in this experiment,
the sensitivity to absorption corresponds to an effective absorption path length of 3 km assuming the cavity is completely
filled with the sample. For a cw laser, the effective absorption path length is estimated to be 50 km. Absorption spectra
of various molecules such as CO2, CO, H2O, H2S, C2H2 and OH were recorded separately in the cell and/or in low-pressure methane and propane flames. The presented measurements
demonstrate simultaneous in situ detection of three molecular products of chemical reactions at different flame locations.
Variation of the relative strengths of OH absorption lines with the temperature enables the estimation of the local flame
temperature. The sensitivity of this laser does not depend on the broadband cavity losses and it can be used for in situ measurements
of absorption spectra in hostile environments such as contaminated samples, flames or combustion engines. The presented technique
can be applied for various diagnostic purposes, such as in environmental, combustion and plasma research, in medicine and
in the determination of stable isotope ratios. 相似文献