INFLUENCE OF RADIATION CONDITIONS ON CRACKING OF COMPOSITE SCINTILLATORS

The article analyzes two main hypotheses describing the cracking of a composite scintillator in the irradiation zone. This is the "temperature" and "radiation-chemical" hypothesis of cracking. The analysis is based on experi-mental data that we obtained by irradiating scintillators and the results of model chemical experiments.

INFLUENCE OF RADIATION CONDITIONS ON CRACKING OF COMPOSITE SCINTILLATORS

The article analyzes two main hypotheses describing the cracking of a composite scintillator in the irradiation zone. This is the "temperature" and "radiation-chemical" hypothesis of cracking. The analysis is based on experi-mental data that we obtained by irradiating scintillators and the results of model chemical experiments.

Stress-Strain State and Structural-Phase Transformations of Metal Articles Obtained by Laser Shaping

The article analyses the effect of temperature distribution at different points of the irradiation zone on the nature of leakage of structural-phase transformations. The results of the X-structural analysis are given, which shows the presence of martensite and residual austenite in the treatment zone. The peculiarities of structural-phase transformations during laser heating are studied and their effect on strain value during laser shaping is determined. The results of experimental studies are given, according to which, if the mechanisms for forming the temperature gradient and polymorphic transformations (for 65G steel) operate in parallel, the amount of deformation is one third of the sample for which only the temperature gradient mechanism works (12Х18N10Т steel).

MORPHOLOGICAL AND ELECTRON MICROSCOPIC CHARACTERISTICS OF THE SKIN AND MUCOUS MEMBRANE AT VARIOUS STAGES OF COMBINED TREATMENT OF ORAL CANCER

Using electron microscopic studies, the structural and functional reorganization of the neck skin and mucous membrane in patients with malignant tumors of the oral cavity at various stages of combined treatment is presented. Significant violations of tissue and cellular elements, their ultastructures, especially fibroblasts, intercellular substance of connective tissue and vessels of the microcirculatory bed were revealed, which exhausts the volume of compensatory and adaptive capabilities of tissue and cells included in the irradiation zone. The degree of structural and functional disorders in irradiated tissues is proportional to the amount of SOD.

Пластическая деформация меди в результате воздействия мощного ультрафиолетового наносекундного лазерного импульса

The modification of the polished surface of oxygen-free copper after exposure to a rigidly focused single pulse of a UV Nd:YaG laser was investigated. It was revealed that at pre-threshold energy densities (E ~ 0.6 J / cm2), in the absence of noticeable traces of ablation, an irreversible elevation of the metal surface in the irradiation zone arised. With an increase in the energy density ablation processes noticeably level out this effect.

Process Intensification for the Synthesis of 6-Allyl-6-azabicyclo[3.1.0]hex-3-en-2-ol from 1-Allylpyridinium Salt Using a Continuous UV-Light Photoflow Approach

A new home-made UV photochemical reactor (95 cm of irradiation zone) consisting of a 12 parallel quartz tubes flow reactor, PQT6 (95 cm under irradiation and an internal diameter of 0.6 cm) was assembled to perform photochemical transformations in continuous-flow. PQT6 was evaluated for the photoreaction of 1-allylpyridinium bromide (1a) to 6-allyl-6-azabicyclo[3.1.0]hex-3-en-2-ol (2a), in a continuous process. This technology provides reduced reaction times, continuous production of 2a, and a productivity of 129 mg h−1, corresponding to 1.94 g of isolated 2a after 15 h of irradiation.

Processes connected with local laser heating of TiB2 armor ceramics

The process of high-temperature heating of TiB2 armor ceramics in air in a continuous and pulsed mode of laser irradiation has been studied by the X-ray diffraction and SEM methods. It has been established that, in the irradiation zone, the temperature increases up to 3000 ?C and over, resulting in the decomposition of TiB2 and appearance of ablation products, which, in passage of air, oxidize and form dense films (in the pulsed mode) or ?reticulated? films (in the CW mode) consisting of boron and titanium oxides. The mechanism of laser-induced breakdown of TiB2 ceramics is similar to the mechanism of ballistic destruction.

Изотопно-селективное управление кластеризацией молекул SF-=SUB=-6-=/SUB=- и диссоциация ван-дер-ваальсовых кластеров (SF-=SUB=-6-=/SUB=-)-=SUB=-m-=/SUB=-Ar-=SUB=-n-=/SUB=- ИК лазерным излучением

We present the results of an investigation into the interaction of SF_6 molecules and clusters in a molecular beam with resonant IR laser radiation at different stages of the beam evolution along the axis of its propagation. The beam has been formed as a result of gas-dynamic expansion of a mixture of SF_6 with argon carrier gas during expansion from a pulsed nozzle. The experimental setup and the investigation method are described. It has been shown that selective vibrational excitation of SF_6 molecules with a specific sulfur isotope by a CO_2 laser near the nozzle edge causes suppression of the clustering process of these isotopic molecules. Selective IR excitation of clusters under the conditions of the formed cluster beam leads to isotopically selective dissociation of clusters. Depending on the experimental conditions including different distances of the irradiation zone of particles from the nozzle edge, the results of measuring the efficiency and selectivity of molecular clustering suppression and cluster dissociation processes are presented. It has been shown that both of these processes make it possible to achieve high selectivity values for the ^32S and ^34S sulfur isotopes. In the case in which the clustering of SF_6 molecules was selectively suppressed, selectivity values α ≥ 25–30 have been obtained. Upon selective dissociation of (SF_6)_2 dimers under similar expansion conditions of the gas mixture, selectivity values α ≥ 20–25 for ^32SF_6^32SF_6 dimers with respect to ^34SF_6^32SF_6 dimers have been obtained. Particular attention has been paid to measurements at a high dilution of SF_6 in argon under conditions of predominant formation of (SF_6)_ m Ar_ n mixed clusters. The potential of using studied processes as a basis for the technology of the laser isotope separation are discussed.

DEVELOPMENT AND APPLICATION OF THERAPEUTIC GELS “KOLEGEL” FOR TARGETED DELIVERY OF DRUGS IN TREATMENT OF RECTAL CANCER

A large part of basic research including medical area studies transportation and delivery of drugs directly to the organs, tissues and cells. This interest has been caused by many reasons, and above all, by huge medical and economic benefits of directed transport, reduced side effects and significant reduction of therapeutic drug doses. LLC «KOLETEX» designs and manufactures therapeutic gels for targeted drug delivery - gels «Kolegel» with various drugs, with the aim to improve effectiveness of radiotherapy and prevent radiation reactions. These gels are widely used in major oncology clinics, they have proven to be highly effective in the treatment of cancer. Their application allows to enhance the effectiveness of radiation exposure due to the introduced modifiers (sensitizers), to protect healthy tissue in the irradiation zone, speed up recovery of mucous membranes, resulting in enhanced treatment efficacy, shorten hospital stay and improve patient’s quality of life.

Formation of the Irradiation Zone for Neutron Transmutation Doping Using the Pool-Type Research Reactor

The neutron transmutation doping (NTD) of silicon is usually used for producing different electronic devices like thyristors, VLSI, detectors, etc. This article focuses on the formation of the radiation field to create the technology for silicon NTD implementing a pool-type nuclear reactor. The works includes the analytical consideration of the conditions for achieving the high radial irradiation uniformity of silicon ingots.