Investigation of the pulsed electron and laser irradiation of PLZT ceramics using laser scanning confocal microscopy

Results of the measurement of Raman scattering spectra (RSS) using the laser scanning confocal microscope (LSCM) with the excitation line λ = 441.6 nm of the relaxor PLZT 8/65/35 ceramics irradiated by different doses of laser and high current pulsed electron beams are given. The two-dimensional images and layered scanning data for unirradiated and irradiated parts of the sample were obtained using the Raman-active mode $v_{TO_4 } $ = 536 cm^?1. Space regions with an anomalously high intensity of the $v_{TO_4 } $ mode were found in the irradiated sample. Possible mechanisms of the effect of high current pulsed electron irradiation for the PLZT 8/65/35 are discussed.     

Solution of problems of free torsional vibrations of thick-walled orthotropic inhomogeneous cylinders

With the use of the 3D theory of elasticity, we investigate the problem of free torsional vibrations of an anisotropic hollow cylinder with different boundary conditions at its end faces. We have proposed a numerical-analytic approach for the solution of this problem. The original partial differential equations of the theory of elasticity with the use of spline approximation and collocation are reduced to an eigenvalue problem for a system of ordinary differential equations of high order in the radial coordinate. This system is solved by the stable numerical method of discrete orthogonalization together with the method of step-by-step search. We also present numerical results for the case of orthotropic and inhomogeneous material of the cylinder for some kinds of boundary conditions.     

Biodegradable liposome–chitosan complexes: enzyme-mediated release of encapsulated substances

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Synthesis of a novel chelating ligand from pentane-2,4-dione and 3-aminopropyl[tris(trimethylsilyloxy)]silane. europium(III) and erbium(III) imino enolates

Acetylacetone reacts with 3-aminopropyl[tris(trimethylsilyloxy)]silane to give a mixture of the isomers 4-[3′-tris(trimethylsilyloxy)silylpropyl]iminopent-2-en-2-ol (90%) and 4-[3′-tris(trimethylsilyloxy)silylpropyl]aminopent-3-en-2-one (10%). According to ¹H and ¹³C NMR data, both isomers exist in the cis-and trans-forms. Anhydrous europium(III) and erbium(III) tris{4-[3′-tris(trimethylsilyloxy)silylpropyl]iminopent-2-en-2-olates} were obtained from the mixture of the isomers and the corresponding propan-2-olates Eu(OPr _i )₃ and Er(OPr _i )₃. The resulting complexes are transparent air-stable liquids that are distillable in vacuo and well soluble in photopolymerizable polyorganosiloxane caoutchoucs and urethane acrylate oligomers. The volatility parameters of the europium(III) complex were studied.     

Vapor pressure and heat capacities of perfluoro-<Emphasis Type="Italic">N</Emphasis>-(4-methylcyclohexyl)piperidine

Heat capacities of perfluoro-N-(4-methylcyclohexyl)piperidine (PMCP) have been measured by low-temperature adiabatic calorimetry. The purity of the compound, its triple-point temperature, and its enthalpy and entropy of fusion have been determined. The saturated vapor pressure was determined by comparative ebulliometry as a function of temperature in the 6.2–101.6 kPa pressure range and 374.2–460.9 K temperature range. The calorimetric enthalpy of vaporization at T = 298.15 K has been measured. The following thermodynamic properties were calculated for PMCP: normal boiling temperature, enthalpy of vaporization Δ_vap H _m ⁰ (T) as a function of temperature, and critical parameters. The enthalpies of vaporization at 298.15 K obtained experimentally and by calculation methods match within their error limits, which validates their adequacy and the adequacy of the Δ_vap H _m ⁰ = f(T) equation as an extrapolation.     

Effect of the phase state of the lipid bilayer on the structure and characteristics of the polycation-(anionic liposome) complex

Interaction of the cationic polymer poly-N-ethyl-4-vinylpyridinium bromide with bilayer vesicles (liposomes) composed of zwitterionic dipalmitoylphosphatidylcholine and anionic cardiolipin (the molar fraction of the negatively charged cardiolipin groups is 0.2) is studied. The composition and characteristics of the polycation-liposome complex are shown to be controlled by the phase state of the lipid membrane. Liposomes whose membranes exist in their LC state (“liquid” liposomes) keep their integrity in the complex with polycation. The adsorbed polycation can be completely removed from the liposomal membrane by the addition excess amounts of a competing polyanion. The adsorption of polycation on the surface of liposomes whose membranes exist the gel state (“solid” liposomes) leads to the formation of defects in the membrane, and the polycation’s adsorption with such liposomes becomes irreversible. The defects that form are also preserved when solid liposomes on whose surface the polycation is sorbed are transformed into the liquid state. Moreover, the reversible contact between polycation and liquid liposomes becomes irreversible once the liposomal membranes bound to the polycation transform into the solid state.