Mutual coupling of elements in finite microstrip antennas

The mutual coupling of the radiating elements in microstrip antennas is studied using a rigorous electrodynamic approach in which the field singularities at the radiator edges are taken into account with analytic accuracy. A spectral method is employed in combination with a method of semi-inversion by extraction of the Green-function singularity. The degree of interaction of the elements of microstrip structures at the fundamental and higher current harmonicsis determined, and the applicability of various approximations is assessed.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, No. 8, pp. 688–701, August, 1992.     

Complexes of Cobalt(II) and Zinc(II) with Heterocyclic Compounds Derived from 1,3-Indanedione

Complexes of Co(II) and Zn(II) with three-membered structures containing 1,3-indanedione, 1,3,4-thiadiazole, and pyridine moieties were obtained.     

Laser-pulse fluctuations due to thermal self-action in a turbulent atmosphere

Conclusions Refractive-index fluctuations caused by heating alter the intensity and phase fluctuation spectra arising from the turbulence. The large-scale part of the spectra is weakened, whereas the small-scale part is strengthened, and the spatial-frequency range in which the fluctuations are attenuated becomes narrower as the beam energy increases. Correspondingly, the fluctuation structure functions alter. For values of the arguments in those functions less than the radius of the first Fresnel zone , the thermal nonlinearity causes increases in the structural functions D_, with the energy. For , the dependence of D_, on energy is nonmonotone, with the fluctuations at first weakened but then strengthened. The reduction in fluctuation variance and the improvement in coherence is less pronounced over long lines than on short ones. The range in which geometrical optics can be used to derive the fluctuations is independent of the nonlinearity and is defined by k₂z/2k /4. The trend to the diffraction asymptote becomes slower as the nonlinearity increases.Atmospheric Physics Institute, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 32, No. 9, pp. 1063–1071, September, 1989.     

Macroheterocyclic Compounds with 2,3-Pyridino(pyrazino)pyrrole and 1,3,4-Thiadiazole Residues

Novel symmetrical macroheterocyclic compounds were prepared by the reactions of 2,3-dicyanopyridine and 2,3-dicyanopyraine with 2,5-diamino-1,3,4-thiadiazole in butanol in the presence of sodium butylate. Physicochemical properties and biological activity of the products were studied.     

Reflection of a focused light beam in a kerr medium II. Numerical solution of the wave equation

The problem of studying the self-effect of a light beam in a nonlinear medium, and its scattering and reflection by the collapse region has been reduced to solving a system of high-order differential equations. This enabled us to use the Runge-Kutta method which improves considerably the accuracy in solving self-effect problems as compared with the conventional phase screen method. The self-effect and reflection of a light beam from the collapse region where the beam diameter decreases to the light wavelength is investigated numerically. Calculations confirmed the main conclusions of the approximate solution of this problem which we obtained earlier in [1].Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 8, pp. 1014–1025, August, 1996.The author is grateful to A. Consortini, J. C. Dainty, S. M. Flatte, R. F. Sharma, A. S. Gurvich, V. P. Kandidov, and V. I. Talanov for their help in this work and V. I. Tatarsky for the discussion and presentation of the results of this investigation at the Symposium on Progress in Electromagnetics Research (PIERS-95) in Seattle, USA.This work was supported in part by the International Foundation for Fundamental Research and by the Government of the Russian Federation (Project codes MR1000 and MR1300).     

Surface second-harmonic generation: A novel technique for ps-pulse duration measurements

Second-harmonic generation from dye adsorbates has been successfully used to measure the duration of ps pulses. In the red and in the blue-green spectral range pulse durations of 2.4 and 6.1 ps—in agreement with streak camera measurements — have been obtained from collinear, slow autocorrelation traces.     

New integral equation for the calculation of the structure and properties of dense liquids

Journal of Structural Chemistry - The modification of the relationship between the direct correlation function c(r) and the potential Φ(r) and the complete correlation function h(r), which has...     

NMR spectra and conformation of cembrene in solution

Using dimeric NMR spectroscopy, a complete interpretation of the¹H and¹³C NMR spectra of the diterpene hydrocarbon cembrene has been made. The experimental values of the SSCs for the¹H atoms in the PMR spectra of cembrene agree well with those calculated for the lowest-energy (“crystal”) conformation. In the light of the observation of intramolecular NOEs and of the low-temperature¹³C NMR spectra, it has been concluded that the cembrene molecule retains the “crystal” conformation in solution.     

Dependence of the growth-regulating activity of macrocyclic allyl alcohols of the cembrane series on the stereochemistry of the disubstituted double bond

With the use of a number of known and two specially synthesized cembranoids it was established that the growth-inhibiting activity of membrane alcohols does not change appreciably on the inversion of the configuration of the ² double bond in their molecule.Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. V. N. Sukachev Forestry and Wood Institute, Siberian Branch, Academy of Sciences of the USSR, Krasnoyarsk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 638–641, September–October, 1990.     

Synthesis of Μ-nonalactone and Μ-undecalactone

Summary -Amylbutyrolactone and -heptylbutyrolactone were synthesized by free-radical addition of hexanol-1 and octanol-1 to acrylic acid.