Temperature behavior of magnetoelectric interaction in composite PZT-nickel disk resonators

The temperature dependences of the characteristics of magnetoelectric interaction in composite disk resonators made up of Ni and PZT layers are studied. Measurements are taken on monolithic resonators, prepared by electrolytic deposition of Ni on PZT, and resonators prepared by gluing Ni and PZT layers. In the temperature interval 220–380 K, the frequency of the monolithic resonators changes by up to 16% and that of the glued resonators, by 4.5%. It is shown that the efficiency of magnetoelectric interaction declines with increasing temperature, since (i) the piezoelectric modulus and piezomagnetic coefficient of the layers vary, (ii) the PZT permittivity rises, and (iii) the layer-to-layer adhesion weakens due to softening of the glue. The results can be used in developing techniques for stabilizing the magnetoelectric interaction characteristics of composite structures.     

Experimental determination of the absolute cross-section of giant Raman light scattering by metal-metal adatom complexes at silver electrode

Changes in the background intensities in giant Raman scattering spectra for silver surface in silver sulfate solutions, appeared at the varying of the silver galvanostatic deposition current near the silver electrode equilibrium potential, are measured. The connection between the silver adatom concentration and the intensity of the giant Raman scattering background allowed determining the absolute cross-section for the giant Raman scattering involving adatom-metal complexes: 1.02 × 10⁻²⁷ cm²/adatom in sulfate solutions.     

Interaction of Dialkyl (α-Carbomethoxy-β,β,β-Trifluoro-Ethyl) and Dialkyl-S-Carboethoxychloromethylthiol Phosphates with Mammalian Esterases. Role of Esterases in Toxicity Mechanisms

Abstract

The interaction of insecticides (RO)₂P (0)OCH (CF₃) COOCK₃ (I) and (RO)₂P(0)SCH(X)COOC₂H₅ (X=Cl(II), Br(III); R=Me, Et, Pr, i-Pr, Bu, i-Bu, Am, Hex) with acetylcnolinesterase (ACnE), butyrylcholinesterase (BChE) and carboxylesterase (CE) was studied in connection with their role in organo-phosphate toxicity mechsnisms. Toxicity of I–III to mice was determined. I–III were not hydrolysed by CE and irreversibly inhibited all the enzymes, II, IIi had a greater inhibitory potency compared to I: lgk^II _AChE = 2–4 (I), 6 (II, III); lgk^II _BChE = 3–6 (I), 5–8 (II, III); lgk^II _CE = 3–7 (I), more than 8 (II, III). With multiple regression analysis the dependence of antienzymatic activity on hydrophobicity and steric properties of alkyl substituents was investigated. The contribution of the hydrophobic interactions to dChE and CE (enzymes-“sites of loss”) inhibition was the same and more significant than that to AChE (target enzyme) inhibition. Steric effects are more important in AChE inhibition. The dependences lg(I/LD₅₀) = f(ΓΠ) for I–III were in great extent determined by binding with nonspecific esterases that rises with increasing hydrophobicity. These results indicate that nonspecific esterases CE and BChE play a buffer role in toxic action of I and especially II and III.     

Expansion of a two-component plasmoid in a vacuum

Numerical integration of the equations of two-fluid hydrodynamics is used to solve the problem of the one-dimensional expansion in a vacuum of a quasineutral plasmoid, consisting of a mixture of ions of different charges and masses. A space-time picture of the change in me hydrodynamic quantities and the electric field is obtained, and the effect of the ion mass and charge is investigated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 66–71, February, 1978.     

Effect of the conditions of an underground explosion on the mechanical characteristics of the surrounding medium

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 44–49, May–June, 1989.     

Molecular mechanism of gelation upon the addition of water to a solution of poly(acrylonitrile) in dimethylsulfoxide

The solidification of a solution of poly(acrylonitrile) (PAN) in dimethylsulfoxide (DMSO) upon introduction of water into the solution is studied by Raman spectroscopy. In the absence of water, DMSO molecules are found to produce dipole-dipole bonds with PAN molecules. Upon the introduction of water, DMSO molecules produce hydrogen bonds with it and bands at 1005 and 1015 cm⁻¹ appear in the Raman spectrum, which are assigned to the valence vibrations of S=O bonds involved in the hydrogen bonds. Simultaneously, water molecules produce hydrogen bonds with PAN molecules: R-C≡N...H-O-H...N≡C-R, where R is the carbon skeleton of a PAN molecule. Accordingly, a band at 2250 cm⁻¹ arises in the Raman spectrum, which is assigned to the valence vibrations of C≡N bonds producing hydrogen bonds with a water molecule. When the water content is low and the DMSO concentration is high, the length of the hydrogen bonds varies in wide limits and the band at 2250 cm⁻¹ is wide. As the water content rises, DMSO molecules come out of PAN, the variation of the hydrogen bond length in it decreases (the band at 2250 cm⁻¹ narrows), and a high-viscosity system (gel) arises that consists of PAN molecules bonded to water molecules via “equally strong” hydrogen bonds.     

Effect of an electric field on the characteristics of magnetoelectric interaction in a ferromagnet-ferroelectric composite structure

The characteristics of the magnetoelectric interaction in a planar nickel-lead-zirconate-titanate structure have been studied in a dc electric field applied to the ferroelectric layer. A hysteretic field dependence of the efficiency and frequency of the resonant magnetoelectric interaction has been revealed, and the vanishing of the interaction efficiency in the range of polarization switching fields due to changes in the permittivity, the piezoelectric modulus, and the dielectric loss of the ferroelectric has been observed. It has been shown that the electric field leads to a significant change in the rigidity of the ferroelectric layer.     

Study of structural phase transitions in YBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>6+δ</Subscript> by x-ray photoelectron spectroscopy

We have used x-ray photoelectron spectroscopy to investigate the charge state of oxygen found in the basal structural plane of YBa₂Cu₃O₆+γ.. We have observed a change in this state after thermal treatment, with a transition to the adjacent structural phase region. We have shown that changes in the charge state of oxygen can be used as an indicator of structural changes occurring in YBa₂Cu₃O₆+δ.. We have found that the rate of structural relaxation yttrium barium cuprate depends on the amount of structural water it contains. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 195–198, March–April, 2007.     

Application of a quasichemical variant of the method of cluster components to binary melts

Application of the quasichemical method of cluster components to binary melts in systems with chemical compounds in the solid state and in systems with a simple eutectic is examined. The approach proposed is an extension of the model of quasi-ideal Fischer solutions to an arbitrary number of chemical compounds. In addition to the thermodynamic properties, it permits discussion of different concentration-responsive physical properties of the melts. A computation performed for the systems Pd-Al and Pd-Si exhibited satisfactory agreement with the experimental results.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 57–60, July, 1977.