Radical Processes in the Low-Temperature Radiolysis of Liposome Dispersions

Processes occurring with the participation of radiolytic radicals in the low-temperature radiolysis of aqueous liposome dispersions were studied. The initial radiation-chemical yields of the resulting radicals were determined, and the transformations of these radicals upon freezing-out the systems were examined. It was found that ionol (2,6-di-tert-butyl-4-methylphenol) introduced into the lipid bilayer of liposomes is an effective scavenger of radiolytic species formed in a frozen (77 K) dispersion upon irradiation.     

Diffractive optical elements and quasioptical schemes for experiments on a high-power terahertz free-electron laser

We have developed reflective diffraction optical elements (DOE) for focusing monochromatic coherent radiation of 400 W terahertz Novosibirsk free-electron laser (FEL). Operational characteristics of two modifications of the refractive kinoform lenses were studied. Quasioptical Toepler system with terahertz radiation recording by a thermosensitive luminescent screen was fabricated for the examination of film and solid deformation. A system for real-time terahertz radioscopy of objects with image recording with a microbolometer matrix (MBM) was fabricated. Images of objects illuminated with a plane wave or diffuse radiation were studied with the MBM. It was shown that the speckle pattern, which appears in the second case, can be averaged by means of the scatterer rotation.     

Spectral composition of the pulse generation of the N2 molecule in the3Πg(B)→3Σ11 +(A)transition

New lines in the infrared generation spectrum of molecular nitrogen are reported. The generation lines are attributed to the vibrational-rotational transitions of the first positive system of nitrogen. The distinctive features of the generation spectrum are interpreted within the framework of the direct electronic collision hypothesis. Excitation of the rotational structure is considered on the basis of a simplified model which affords qualitative agreement with the experimental data.The author is grateful to Profs. V. I. Malyshev, I. I. Sobel'man, and G. G. Petrash for their useful comments. He is also deeply indebted to the late Prof. P. A. Bazhulin for his assistance and support in the phase of the study involving pulse-generating gas lasers.     

Laser isotope separation of carbon by multiple IR photon and subsequent UV excitation of CF3I molecules

A new approach to laser isotope separation is considered. It is based on collisionless multiple photon ir laser excitation and subsequent uv laser dissociation of vibrationally excited molecules. TEA CO₂ and excimer XeF, XeCl lasers are used for ir excitation and uv dissociation, respectively. The products of photolysis (C₂F₆) are enriched with¹²C.     

Multiple infrared photon absorption in OsO4

Multiple ir photon absorption spectra (MPAS) of OsO₄ are obtained in the range of energy fluencies from 3·10⁻² to 1.26 J/cm². A possible interpretation of MPAS is given on the basis of weak forbidden rovibrational transitions. The stepwise character of the absorption on the laser energy fluence is observed.     

Dependence of the atomic structure and surface relief of platinum foils on the annealing and rolling conditions

The effect of cold rolling, polishing, and thermal annealing conditions on the atomic structure and surface geometry of platinum foils has been studied. The surface morphology has been analyzed using low-energy electron diffraction, atomic force microscopy, and scanning tunneling microscopy. The chemical composition of the surface has been evaluated by Auger electron spectroscopy. It has been demonstrated that a variation in the conditions used for the preparation of the samples makes it possible to produce surfaces with different degrees of perfection from atomically smooth to rippled, fractal, and diffraction-disordered surfaces.