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1.
Some features of the propagation of one-soliton successions in the third order dispersion region are presented for the case where the phase difference between adjacent pulses is rads. We show that this considerably improves the stability of the pulses in the zero-dispersion region. Walk-off can be diminished by increasing the number of pulses in the succession. These features may help optimize the bandwidth of non-linear fibre communication links. 相似文献
2.
A. P. Mitev V. L. Strashilov J. I. Burov 《Applied Physics A: Materials Science & Processing》1991,52(6):369-372
A method for direct measurement of the temperature coefficients of the velocities of bulk acoustic waves propagating along arbitrary directions in crystal planes is described. It represents a specific version of the Schaefer-Bergmann acoustooptic diffraction in which the effect of the temperature is precisely compensated by biasing the acoustic frequency. The method is equally applicable to the determination of other kinds of velocity coefficients. 相似文献
3.
Todorov Vladislav T. Dutsov Chavdar Ch. Cassette Philippe Mitev Krasimir K. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(8):3249-3258
Journal of Radioanalytical and Nuclear Chemistry - This work shows a study of the effect of the non-uniformity of photocathode response on the energy resolution of plastic scintillators optimized... 相似文献
4.
D. J. Mitev Tz. Ivanova C. S. Vassilieff 《Colloids and surfaces. B, Biointerfaces》2002,24(3-4):185-192
A formal kinetic model of lipid layer formation at an interface in contact with a liposomal suspension is developed and investigated. Neglecting diffusion (for sufficiently high bulk concentrations) the kinetic scheme consists of two consecutive processes: (I) irreversible transformation of ‘soluble’ intact vesicles from the ‘subsurface’ layer into ‘adsorbed’ ones (‘defected’ or ‘ruptured’ liposomes, ‘mesophases’); and (II) irreversible transformation of the ‘adsorbed’ vesicles into a lipid monolayer. The resulting set of two differential equations is analyzed making use of the ‘steady-state concentration’ approach (with ‘adsorbed’ vesicles as intermediate compound). Numerical results illustrate the predicted kinetic behavior which depends on the relative magnitude of the rates of the two consecutive processes. Approximate analytical solutions in the case of a much slower process I are obtained in some limiting cases. The model is used to estimate rate constants from previously established experimental kinetic data at the air/water interface. 相似文献
5.
We report the first experimental measurement and theoretical estimation of seventh
eff
(7)
and ninth
eff
(9)
order effective nonlinear susceptibilities. The correlation of ninth, seventh and fifth harmonic signal efficiencies in various phase-matched mixtures of Ar (or Xe) and sodium atoms, is experimentally investigated. Using direct and cascade processes of harmonic generation, the modulus ratio is measured for the higher nonlinearities, which allows an estimation of
eff
(7)
and
eff
(9)
from the lower order optical susceptibilities. Results from numerical calculations of atomic nonlinear susceptibilities up to the ninth order, accounting for the discrete spectrum and the continuum, are presented. 相似文献
6.
We report experimental investigation of direct fifth harmonic of Nd3+: glass laser radiation (1060 nm) in metal vapor. Using various mixtures of sodium vapor and xenon in order to achieve a phase-matching, we observed direct as well as cascade nonlinear processes. The first measurement of effective fifth-order nonlinear susceptibility χ(5)eff in atoms, is performed. 相似文献
7.
8.
In this paper we describe an automatic procedure for successively reducing the set of possible nonzeros in a Jacobian matrix
until eventually the exact sparsity pattern is obtained. The dependence information needed in this probing process consist
of “Boolean” Jacobian-vector products and possibly also vector-Jacobian products, which can be evaluated exactly by automatic
differentiation or approximated by divided differences. The latter approach yields correct sparsity patterns, provided there
is no exact cancellation at the current argument.?Starting from a user specified, or by default initialized, probability distribution
the procedure suggests a sequence of probing vectors. The resulting information is then used to update the probabilities that
certain elements are nonzero according to Bayes’ law. The proposed probing procedure is found to require only O(logn) probing vectors on randomly generated matrices of dimension n, with a fixed number of nonzeros per row or column. This result has been proven for (block-) banded matrices, and for general
sparsity pattern finite termination of the probing procedure can be guaranteed.
Received: April 29, 2000 / Accepted: September 2001?Published online April 12, 2002 相似文献
9.
Two types of secondary polynitroalcohols (PNA) were prepared by AN-reaction of butadiene-styrene nitrooligomer (BSNO) and acetaldehyde. The corresponding yields were 58-64% and 25-33%. The reaction was conducted in water-ethanol solution in the presence of alkaline base as catalyst at temperatures from 40 to 60 °C, for 3.5-4 h. Introduction of hydroxyethyl groups by AN-reaction of BSNO to acetaldehyde increased the polarity and thermal stability of PNA as compared to BSNO. By using IR spectroscopy and liquid absorption chromatography on silica gel, PNA were found to be polyfunctional compounds, that contained structurally and functionally heterogeneous fractions. The quantitative functional composition of the first PNA type as well as their main fractions were determined by evaluating the relative content of nitro-, carbonyl and hydroxyl groups in the products. PNA are considered to be starting materials for the preparation of polynitrourethanes and salts of N-containing sulphonic acids. 相似文献
10.