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Prospects of oxygen alloying of alloys in the process of deposition of rods on parts from titanium alloys aimed at raising their hardness are considered. Experiments on fabrication of samples of titanium alloys with remelting of filler rods with oxide coating formed by plasma electrolytic oxidation are performed. The main mechanical characteristics of the overlay rod material modified by introduction of oxygen from the oxide layer are determined and the structural features of the material are analyzed.

The possibility of the application of a mobile unit with several travelling electrodes to form oxide coatings via the microarc oxidation on various surfaces of large-scale articles made of titanium alloys has been demonstrated. The application of several electrodes has promoted improving the treatment performance and forming more homogeneous oxide layer on the treated surface.

Allergic rhinitis is one of most widespread human diseases associated with severe limitations in physical, psychological, and social aspects of life, which is the reason for the decline in quality of life. The drugs of first choice in patients with symptoms of seasonal and perennial allergic rhinitis of intermittent as well as of persistent courses are antihistamines of 2nd generation with high affinity to H1-receptors. The article is about a new representative of the above group of drugs, the original drug Niksar® (bilastine).

Producing of safer products by applying high pressure on biosystem, is a novel non-thermal technology with significant results in maintaining the natural characteristics of the food items. Modeling of the microorganism kinetics inactivation by the high pressure was determined and certificated by an experimental approach. It is established that the basic laws of the joint influence of the factors of high pressure, temperature and process time on microorganisms and vitamin C are reproduced in the framework of the linear kinetics. By choosing the values of the process parameters (pressure, temperature, duration of the process), the averaged thermodynamic characteristics of micro flora can be changed, as well as the value of the activation barrier of the biochemical reaction. Based on these results, working 40 min at the pressure 400 MPa, and temperature 300 K, the microorganism activity is minimum, and the vitamin C contain is preserved about 90 percent.

The physical validity of the mechanism proposed by the author is discussed. According to the theory, prolonged exposure to weak electromagnetic fields leads to enlargement of microbubbles and degassing of bioliquid. Degassing alters the physical and chemical properties of bioliquid that affect some medical and biological indicators. The following changes in some blood parameters during degassing in vitro were analyzed: decrease in the glucose concentration, abnormal activation of blood clotting, increase in the rate of blood cell aggregation, decrease in the effectiveness of aspirin as an inhibitor of platelet aggregation and the slowing of indirect anticoagulants. All this is evidence of possible connection between environmental electromagnetic pollution and the risk of cardiovascular disease.

The sharply higher demand for uranium for nuclear power during 2010–2050 and possibilities of modern mineral-material resources to meet these needs are evaluated on the basis of an analysis of IAEA information and other publications. Forecasts to 2030 show adequate reserves and resources for producing the required amount of uranium. New deposits will supply production expansion beyond 2030.

Results are reported from a comprehensive test, under real conditions, of technology for removal of 90Sr from the waters of the Techa reservoir cascade. This technology includes stages of preliminary decontamination, ion exchange softening with desorption and carbonate precipitation of hardening salts and 90Sr from the desorbates, sorption cleanup on natural zeolites, and concentration of the strontium-containing carbonate precipitates. After the precipitates are removed, the solutions are reused in the desorption stage. The quality of the decontaminated water meets all the requirements for discharge into open drainage network in terms of all indicators. (The specific activity of 90Sr is 3–5 Bq/liter in the filtrates.) The 90Sr is concentrated by a factor of about 900 as solid radioactive waste in the form of a sediment with a moisture content of 50% and by about 1700 as air-dried solids. As a preliminary estimate, the operating cost of decontaminating 1 m3 of water in the V-11 reservoir is 200 rubles.

The prospects for supplying zirconium and hafnium-the main structural and prospective absorbing material for thermal reactors-are examined in accordance with the strategy for the development of nuclear power in our country up to 2030. The present situation concerning the use of Russian nuclear fuel is described. The characteristics of the main zirconium alloys used in domestic and foreign thermal reactors and the approximate requirements for baddeleyite and zirconium concentrates, the distribution of balance zirconium reserves, and the requirements of the nuclear industry for hafnium metal and hafnium compounds are presented.

A method of sorption extraction of uranium from solutions and pulps containing macroscopic and trace impurities by anionites with gel or porous structure has been developed. An anionite saturated in the initial solution or pulp is treated with a solution of an alkaline agent, to which an alkaline-metal salt is added, and is presaturated with uranium in a period of 2–5 h in contact with a commercial-grade desorbate.

Using the numerical simulation method the parameters for the enrichment of isotope H-D-T mixture by different regimes of its filtration through multicell palladium membrane are founded for different values of temperature, pressure as well as initial compositions of isotope mixture.

The method used to develop sorption-extraction processes in uranium hydrometallurgy over the last 50 years is examined. The first-generation sorption-extraction processes, ionites, and apparatus are described. Data for the second-generation sorption-extraction technology and improvement of apparatus are generalized. The third generation of these processes is characterized by the adoption of porous anionites AM-p and AMP-p in order to make the kinetic characteristics of the sorption and extraction processes closer to one another, by sorption leaching of uranium ores, and by adoption of double synergetic mixtures of extracting agents at the stage of repurification of the commercial reclaim and by the development of fast sorption processes for extracting uranium from productive solutions used in mound and underground leaching. The fourth-generation processes are characterized by the use of high-volume vinyl pyridine ionites, tertiary synergetic mixtures at the extraction stage, combined extraction-desorption processes, solid-phase regeneration of saturated ionites, and conversion of absorbed anions of uranyl-trisulfate into nitrate and chloride complexes. 1 figure.

Under the new economic conditions, the problem of decreasing substantially the cost of uranium in the final product obtained by processing mined ores has become acute. A search has shown that the problem can be successfully solved by closely combining hydrometallurgical conversion in plants with inexpensive processes, such as large-batch sorting in radiometric monitoring stations, radiometric piecewise separation, and mound leaching of low-grade ore. Radiometric enrichment produces tailings as well as average and rich concentrates. The rich concentrate will be processed using a separate scheme without a sorption process. A specific example of the combined scheme and the apparatus developed for implementing this scheme are examined. 1 figure, 3 tables, 10 references.

The characteristics of BaF2 barium fluoride crystals, grown from the materials provided by manufacturers, were investigated. The parameters which are important for application of the crystals in low-energy physics, electromagnetic high-energy calorimeters for detecting γ rays and electrons, and measurement of energy in the maximum possible range from tens of MeV up to hundreds of GeV, as well as applications in medicine, instrument building, geology, and so on, were measured. 7 figures, 3 tables, 13 references.

Sorption-extraction processes for obtaining finished coproducts during processing of uranium ores with valuable components, such as Mo, V, W, Re, Au, Sc, rare-earth elements, Y, Cs, Cu, Ta, Nb, Zr, Hf, Mn, Sn, and Se, are described. Special attention is focused on experience in extraction decontamination of phosphoric acid with its uranium and thorium content decreased by a factor of 20 and obtaining from it ecologically pure phosphate fertilizers and feed phosphates.

The separation coefficients of ZrF4(HfF4) and metal fluoride impurities in the process of vacuum sublimation between 900 and 1200 K in the molecular vaporization regime were calculated. The separation coefficients were found to decrease in the order CrF2> MnF2> NiF2> CoF2> MnF3> FeF2> AlF3> CrF3> CuF2> FeF3 . The conditions for purification of ZrF4and HfF4by vacuum sublimation were optimized. The total impurity content in both fluorides was found to increase with the product of the evaporation rate per unit area and the degree of evaporation. Fe was found to be the most difficult-to-remove impurity in ZrF4and HfF4 . The production rate of the sublimating plant is about 100 kg/year of ZrF4and HfF4sublimates. ZrF4was used to prepare optical fibers for laser applications and noncontact fiber sensors for monitoring the composition and temperature of liquid radioactive waste. Fluorohafnate glasses were used to fabricate radiation-resistant scintillating modules of dimensions 20 × 30 × 150 mm, weighing ≤0.5 kg.

Experimental work on transferring compact weapons plutonium by pyrochemical methods into its compounds was generalized. Powdered plutonium dioxide was obtained by interaction with moist air at 480–500°C. PuH3 was synthesized by interaction of the metal with hydrogen at 280°C. PuF3 was formed in an interaction of dioxides with HF and H2. The reaction of plutonium hydride with HF also resulted in plutonium trifluoride. PuF4 was synthesized by interaction of PuO2 with HF. In summary, compact plutonium can be transfered by water-free methods into its powdered compounds, which can be used in investigations for developing new types of fuel elements for power reactors. 6 figures, 2 tables, 16 references.

The scientific-research work on reprocessing spent oxide fuel by gas-fluoride method is reviewed. The refining possibilities of the basic stages of gas-fluoride technology are studied. The possibility of separating most fission products from the ashes at the fluoridation stage is confirmed experimentally. The use of fluoride sorbents (NaF, BaF2) permits reaching a total coefficient of removal of fission products from UF6 at the 107 level. It is shown that deep extraction of plutonium from oxide fuel is possible. The results of investigations on pyrohydrolysis of UF6 and a mixture of UF6 with PuF6 with production of granulate of the oxides with the required density with fluorine content 0.005 mass % and oxygen coefficient 2–2.1 are presented.

Systematic investigations were performed of the intensification of ion-exchange processes for extracting uranium from solutions and pulps during processing of polymetallic mineral stock. The crux of the process developed consisted in creating conditions under which polymer forms of uranyl are formed in solution and in the ionite phase. Several types of sorbents were studied. It was shown that the sorption characteristics were improved, and the optimal conditions for the process were determined. The character of the polymerization transformations of uranyl ions in the sorbent phase was determined. 5 figures, 11 references.

IR spectroscopy was used to identify and study the structure and properties of domestic and foreign samples of ionites synthesized for the nuclear industry. The mechanism of uranium absorption from complex salt solutions and the interaction of uranium with functional groups of ionites were investigated. The changes in the structural and chemical properties of ionites subjected to prolonged commercial use were estimated. The dependence of the process of uranium sorption on anionites and the dynamics of accumulation of silicon compounds in the anionites were found. A comparative analysis of the data showed that the capability of an anionite to absorb silicon does not always interfere with uranium sorption. 6 figures, 2 tables, 9 references.

The ecological problems arising in open-pit and underground production of solid-mineral deposits are described, the basic advantages of underground leaching, the reasons and sources of contamination of the environment during production of the deposits by underground leaching, and measures for protecting the air, soil, and surface and underground waters, and methods for rehabilitating underground waters are presented. Investigations of natural and artificial neutralization of waste underground-leaching solutions during the interaction of the solutions with technogenically unchanged rocks, performed at one of the uranium deposits, are described. An ecological monitoring scheme is proposed for the Khiagdin deposit.

The properties of cerium trifluoride scintillating crystals, grown in Russia using the Stockbarger's method, were investigated. The characteristics of CeF3, PbWO4, Bi4Ge3O12, and BaF2 crystals were compared for use in electromagnetic calorimeters to detect electrons and γ-rays of medium and high energies.

The characteristics of various methods of desorption of uranium and other valuable impurities with ion exchangers, saturated in the sorption cycle, are presented. It is shown that the desorption methods developed give the maximum yield of metals in the output desorbate and simultaneously substantially decrease the impurity content in the finished product.

Almost 50 years of work at the All-Russian Scientific-Research Institute of Chemical Technology on the hydrometallurgy of uranium is surveyed. Autoclave leaching, sorptional pulp processing, and extractional deposition of pure uranium compounds permit the processing of lean uranium ores. Advanced low-waste technologies have been developed, with radical reconstruction of the processing plants.

Low-temperature nonaqueous nitration of metallic uranium in the system TBP tetrachloroethylene-NO2 is studied. Dissolution of U in a dipolar aprotic solvent (TBP, DMF, acetonitrile, nitromethane, DMSO, diethylformamide) proceeds with the formation of U(VI) compounds. The activation energy of the process is estimated at 48.2 kJ mol−1, and the partial order of the reaction with respect to NO2 is 1. The effects of the TBP concentration and water addition on the nitration are examined. In the system TBP-tetrachloroethylene, the nitration rate is maximal at a water content of 1.0–2.0 vol %.

Low-temperature chlorination of uranium metal in the TBP-TCE-Cl2 systems was studied. Dissolution of uranium in the dipolar aprotic solvent proceeds with formation of U(IV) compounds. The activation energy of this process is 31.24 kJ mol−1, and relative reaction order with respect to Cl2 is 2. The effect of TBP concentration on chlorination was examined. The chlorination rate sharply increases at a water content in the TBP-TCE system of 0.2–0.6 vol %.

Reactions of anhydrous uranium tetrachloride with tributyl phosphate, dimethyl sulfoxide, diisoamyl methylphosphonate, hexamethylphosphoramide, diamyl sulfoxide, trioctylphosphine oxide, triisoamylphosphine oxide, dioctoxyphenyl selenoxide, diphenyl selenoxide, triphenylarsine oxide, and trioctylamine oxide in acetone and acetophenone were studied. The 1 : 1 and 1 : 2 complexes were revealed by conductometric titration in acetone and acetophenone solutions. The enthalpies of donor-acceptor reactions of O-bases with UCl4 in acetone and acetophenone were determined. These enthalpies in acetone linearly depend on the donor number of the O-base.

A reagent-free electrochemical method for separating ammonium polynitrate from acidic commodity desorbates, obtained from underground leaching of uranium with sorption reprocessing of the productive solutions, is investigated. The optimal technological parameters of the process are determined. Investigations and full-scale tests established that the method developed will make it possible to increase the quality of the separated yellow cake and decrease the operating costs for obtaining 1 kg of uranium in finished product by 20% compared with chemical deposition of ammonium polyuranate.

The silicide formation process in (NiV)Si and (NiRe)Si thin film systems is investigated under heat treatment with X-ray and electron diffraction analysis, electron microscopy, and secondary ion mass-spectroscopy methods. It is shown that a refractory metal dopant changes the reaction temperature, the phase formation order, and the elemental distribution over the structure depth. A model is suggested interpreting the results obtained. [Russian Text Ignored].

A study is made of the cascade process which describes the energy loss and multiplication of secondary electrons and holes in crystalline silicon irradiated by low energy electrons. The pair creation scattering rates are evaluated in framework of statistical model which takes into account the electron band structure of silicon. Kinetic equations for the excited electron and hole energy distributions are solved numerically in the isotropic scattering approximation for some primary energies E p — E F ⩽ ħω pl . The derived energy distribution function permits a smooth interpolation ƒ( E ) ∼ ⦶ E - E F ⦶ - s . The calculations result in a weak energy dependence of the mean pair creation energy.

An interpretation of the two main maxima in the valence semiconductor optical spectra and an explanation of the shape of the dielectric constant curve are suggested using the quasi-molecular model of these crystals suggested by Tolpygo. According to this model the resonances in the continuous spectrum are due to the transitions to the metastable Frenkel exciton states. The interband transitions give rise only to the background component of the spectrum. Estimates of the parameters of the theory are given and experimental sequences of the model are discussed. [Russian Text Ignored]

Broadening of the angle-resolved photoemission spectra caused by the electron-hole attraction is considered. For the case of a semiconductor with the model parabolic dispersion law the spectral-line shape is found at arbitrary ke and ħω, the energy dependence of the spectrum width is presented too. For the real crystals of silicon, germanium, and grey tin the results of numerical calculations of these values are given in some points ke. The accounting of the electron-hole interaction gives rise to shifts and widths up to 0.1 eV order of magnitude and results in an oscillating spectrum lineshape.

The appearance of areas with a nearly constant interband difference EG(k) near the L- and K-points of the Brillouin zone, corresponding to the absorption peaks E1 and E2, is considered within the model of an electron in a periodic field. Large values of the reduced masses μ‖ result in relatively deep levels of the Wannier-Mot texciton (≈ 0.1 eV for L and ≈ 1 eV for K). To obtain absorption frequencies in agreement with experiment one has to redetermine the periodic potential Wg, as the interband distance at the points mentioned above must exceed the energy of the corresponding absorption peak by the value of the exciton binding energy. [Russian Text Ignore]

In accordance with the recommendations of the World Health Organization [i], the total number of nonpathogenic microorganisms in noninJection medicinal preparations must not exceed i000, and the number of yeast and mold fungi i00 cells in 1 g of the preparation. The presence of pathogenic and facultative pathogenic microorganisms is completely impermissible. The introduction of these recommendations is due both to the danger of infecting a patient by the use of preparations highly contaminated with microflora and to the possibility of the decomposition of the components of noninjection preparations through the activity of microorganisms on prolonged storage [2]. Finally, in a number of clinical situations it is possible only to use sterile preparations, including noninjection preparations. All these facts make the task of seeking methods for sterilizing or reducing the contamination of noninjection drugs an urgent one. One of the most promising methods of sterilizing medical products of very different types is that of radiation sterilization [3]. The advantage of this method obove other methods of sterilization is, in particular, the possibility of sterilizing articles, including drugs, in the packaged form, which excludes the possibility of their recontamination with microbes if the packaging is of suitable quality.

Experimental measurements and theoretical calculations of Si(100) and Si(110) angle-resolved secondary electron emission spectra are presented. We doubly differentiate the spectra by the energy E to extract a fine structure and show its correlation with the electron energy band boundaries. Energy broadening of the boundaries depending on electron lifetime τ (E) leads to decreasing of the fine structure amplitude as τ 2 (E). This allows us to obtain from the experiment an energy dependence of the electron mean free path in the energy range 2–15 eV.

The basic kinetic equation for diagnol elements of the density matrix is solved to obtain the electron energy distribution function. For the case of a model energy independent scattering rate an analitic time-dependent solution is found. For a simple metal the pair-and plasmon scattering rates are computed within the framework of the interacting electron gas theory. Using an approximate energy dependence of the pair scattering rate for the case of low energy of primary excited electrons an analitic form of the energy distribution function is obtained. In general the kinetic equations is solved numerically giving the picture of the electron energy losses for the multiple scattering case.

The results indicate that there is a real possibility of obtaining oil extended SKS-30M-15 rubber with satisfactory physical and processing properties from high temperature, modified latex.

Association potentialities of acrocentric chromosomes were evaluated from the frequencies of associations consisting of two homologues. The evidence obtained enabled one to calculate the frequencies of associations consisting of two nonhomologous and mixed acrocentric chromosomes. Such frequencies turned out to occur 4-fold less than empiric frequencies of the respective associations. This is possible with 2-fold increase in the association potentialities of each acrocentric chromosome entering the association of two nonhomologous and mixed chromosomes. A correlation performed according to Pirson's criterion revealed a good agreement of empiric and theoretic frequencies calculated with due regard 2-fold magnification of the association potentialities. This finding does not reject a hypothesis of 2-fold magnification of the association potentialities in acrocentric chromosomes entering the association consisting of 2 non-homologous and mixed chromosomes.

The discovery of superconductivity in the oxide system La-Ba-Cu1 and the subsequent research on ceramic oxides, Y-Ba-Cu and other metal oxides2–4, has attracted the attention of both physicists and chemists interested in the initial components of high temperature superconductor (HTS) systems. Taking into account the wide scope for the application of HTS in technology, chemists have had to consider short- and long-term perspectives for the adequate production of the initial materials, such as compounds of rare earth elements, strontium, barium and copper for metalloceramics. The question concerns guaranteed raw material sources for HTS production. One such source is Kola apatite Ca5F(PO4)3, which is processed into large amounts of phosphorus fertilizers for domestic use and export5,6.