Complex domain structure in a magnetic film with oblique anisotropy

Analytical formulas have been derived to calculate the distortion of the stripe domain structure in a ferromagnetic film under the action of a bubble domain formed in this film. On the basis of the formulas obtained, an experimentally obtained domain configuration has been calculated. The results of the calculation coincide with the observation data within the experimental error.     

Structure of a matrix based on polysaccharide derivatives for the immobilization of biologically active substances

The supermolecular, molecular, and physicochemical characteristics of natural and modified natural polysaccharides (cotton cellulose, amylose of the U-type) used as supports for obtaining enzyme conjugates have been studied. It has been shown that by varying the process conditions it is possible to obtain cellulose matrices with different amounts of CHO groups and correspondingly different capacities for immobilizing an enzyme and modifying its activity.Institute of the Chemistry and Physics of Polymers, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 44 26 61. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 632–638, July–August, 1997.     

Third-harmonic generation in polyvinylpirrolidone-based metallic complexes

The third-order nonlinear susceptibilities of the aqueous solutions of polyvinylpirrolidone doped with iron and zinc were studied by the method of third-harmonic generation with 1064-nm Nd:YAG laser radiation. The efficiencies of transformation into the third harmonic in these metallic complexes were 8×10^?7 and 5×10^?7, respectively. To determine the role of the Kerr effect in the transformation process, the nonlinear refractive index of the iron-doped polyvinylpirrolidone solution was measured by the Z-scan method and a value of n ₂=?6.7×10^?13 cgs unit was obtained.     

Influence of predelay between interacting picosecond pulses on the nonlinear optical processes of frequency conversion

Received: 7 October 1996     

IR spectroscopy of the acetonitrile molecules in porous glasses

The results of investigation of the IR spectra of optical density under the condition of attenuated total internal reflection of acetonitrile in porous glasses with the pores of different radii are presented. It is established that interaction between the acetonitrile molecules and the porous glass matrix with the pores of small dimensions (1.3–4 nm) significantly effects the spectral characteristics of these molecules.     

Determination and analysis of opiates in complex mixtures by surface-ionization mass spectrometry

The results of studies of the analytical opportunities of surface-ionization mass spectrometry (SIMS) for high-sensitivity and selective detection and analysis of opiate mixtures—natural opium, crude heroin, and narcotic analgesic omnopon—are presented. The experiments were carried out using an MX-1320 chemical mass spectrometer modernized for studying surface ionization (SI). It was ascertained that the opiate mixtures are ionized by highly efficient surface ionization. The bands of M⁺ (for papaverine), (M-H)⁺, (M-H-2nH)⁺, (M-R)⁺, and (M-R-2nH)⁺ ions, where M is a molecule, H is a hydrogen atom, R is a radical, are observed in the mass spectra; they are the sum of the SI mass spectra of components of the mixtures. The series of bands of ions with m/z of 144 and 146 that is characteristic of SI-morphinelike molecules is the main one in the mass spectrum of crude heroin, while for omnopon and natural opium this series is the main at low temperatures of a thermionic emitter (up to ∼900 K). At high temperatures of the thermionic emitter, the band series with m/z of 218 and 220 is the main series. Studies of natural opium, crude heroin, and omnopon have shown that the SIMS method allows analyzing mixtures without preliminary chromatographic separation thereof. The study also contains the results of comparative analyses of opiate mixtures by SIMS and chromate- and mass spectrometry (HP-6890) with electronic ionization.     

Iridoids from Phlomis ostrowskiana Regel plant

Russian Chemical Bulletin - The structures of glycosylated iridoids extracted from Phlomis ostrowskiana R. plant species of Lamiaceae family were determined by mass spectrometry and NMR spectroscopy.     

Optical properties of laser plasma produced by pulses of different duration

The results of experiments on the interaction of laser radiation pulses (at intensities of up to 1015 W cm−2) of different durations (t = 3ps; 300ps; 30ns) with targets in a vacuum chamber are presented. An investigation was made of the optical characteristics of laser plasma in vacuum ultraviolet and X-ray ranges. The intensity of the laser-produced plasma radiation in the range 1–50nm was estimated to be 1010–1012W cm−2. This revised version was published online in November 2006 with corrections to the Cover Date.     

Structure of isoregecoline

The structure of the alkaloid isoregecoline (I) with the composition C₁₉H₂₃O₄N⁺, mp. 284–286°C, isolated previously fromColchicum kesselringii Regel growing in the flood plains of the R. Chirchik has been established. It has been shown by IR, PMR and mass spectroscopy and chemical transformations that (I) is an epimer of regecoline isolated from a plant of the same species.