Structural phase transitions in heteroepitaxial ferroelectric films

The changes in the structural—deformational characteristics occurring during the phase transitions in the crystal lattice of epitaxially grown thin (Ba,Sr)TiO₃ films on the (001) cleavage of MgO crystals have been studied. It is shown that microdeformations along the surface normal of the wall of a c-domain film increase with the temperature and attain maximum values in the vicinity of the phase transition. No decrease in the dimensions of the coherent-scattering regions was observed. The comparison of the deformation of the “average” lattice and microdeformations led to the assumption that the transition from the paraelectric to the ferroelectric phase is accompanied by the dislocation-induced formation of a dipole-glass-type intermediate phase at the temperatures exceeding that of the phase transition.     

Hexafluoroacetone and methyl trifluoropyruvate as precursors of modified esters of N-acyl-N-phenyl-α-amino acids

The C-oxyalkylation of N-aryl--amino acids by hexafluoroacetone (1) and methyl trifluoropyruvate (2), followed by acylation of the products3–13, 15, and17 formed, was carried out. The activity of the synthesized anilides against pathogens of plant fungus diseases was studied.Deceased.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1820–1831, August, 1992.     

Quasielastic neutrino and antineutrino scattering total cross-sections,axial-vector form-factor

Experimental results on the study of quasielastic reactionsv _μ n→μ ^? p and \(\bar v_u p \to \mu ^ + n\) in the energy range 3–30 GeV are presented in this paper. Spark chamber detector with Al filters has been exposed to the wide-band neutrino and antineutrino beams at Serpukhov. Neutrino and antineutrino data have been used to reconstruct the behaviour of axial-vector form-factorF _A (Q ²). We measured the total cross-sections as a function of energy. The parameterM _A =(1.00±0.04) GeV/c² has been determined under the assumption of the dipole parametrization and CVC hypothesis. Upper limit for the second class currents was estimated.     

Space charge and thermal depolarization currents in PZT thin films

Space-charge effects in PZT thin films obtained by rf cathode sputtering were studied. There is evidence that space charge forms in the ferroelectric phase during dielectric aging. Charge accumulation and disappearance were investigated by the method of thermally stimulated depolarization currents. Current peaks due to preliminary poling by a dc electric field and dielectric aging were determined. Effects that can be attributed to the rearrangement of point defects with the production of defect complexes, such as dimers, were observed for the first time. The activation energies for trap depletion (0.98 eV) and defect complex breakdown (1.20 eV) were found.     

Synthesis and properties of an aminocarboxylic polyampholyte based on polyacrylonitrile fiber

Aminocarboxylic fibrous polyampholytes containing up to 2.5 mg-equiv g^?1 weakly acidic groups and up to 2.9 mg-equiv g^?1 weakly basic groups were prepared from Nitron commercial polyacrylonitrile fiber by its treatment with mixed aqueous solutions of diethylenetriamine and sodium silicate. The acid-base properties of the polyampholyte were studied.     

Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions I: beryllium nuclei and beam momenta of +8.9 GeV/c and −8.0 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons, deuterons, and charged pions and kaons, in the interactions with a 5% λ _abs thick stationary beryllium target, of a +8.9 GeV/c proton and pion beam, and a −8.0 GeV/c pion beam. Results are given for secondary particles with production angles 20^○<θ<125^○. On leave of absence at Ecole Polytechnique Fédérale, Lausanne, Switzerland.     

Cross-sections of large-angle hadron production in proton– and pion–nucleus interactions II: beryllium nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons and charged pions, in the interactions with a 5% λ _abs thick stationary beryllium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20° <θ<125°.