Experimental studies of thorium ions implantation from pulse laser plasma into thin silicon oxide layers

We report the results of experimental studies related to implantation of thorium ions into thin silicon dioxide by pulsed plasma fluxes expansion. Thorium ions were generated by laser ablation from a metal target, and the ionic component of the laser plasma was accelerated in an electric field created by the potential difference (5, 10 and 15 kV) between the ablated target and SiO2/Si(001) sample. Laser ablation system installed inside the vacuum chamber of the electron spectrometer was equipped with YAG:Nd3+ laser having the pulse energy of 100 mJ and time duration of 15 ns in the Q-switched regime. Depth profile of thorium atoms implanted into the 10 nm thick subsurface areas together with their chemical state as well as the band gap of the modified silicon oxide at different conditions of implantation processes were studied by means of X-ray photoelectron spectroscopy (XPS) and Reflected Electron Energy Loss Spectroscopy (REELS) methods. Analysis of chemical composition showed that the modified silicon oxide film contains complex thorium silicates. Depending on local concentration of thorium atoms, the experimentally established band gaps were located in the range of 6.0 - 9.0 eV. Theoretical studies of optical properties of the SiO2 and ThO2 crystalline systems have been performed by ab initio calculations within hybrid functional. Optical properties of the SiO2/ThO2 composite were interpreted on the basis of Bruggeman effective medium approximation. A quantitative assessment of the yield of isomeric nuclei in "hot" laser plasma at the early stages of expansion has been performed. The estimates made with experimental results demonstrated that the laser implantation of thorium ions into the SiO2 matrix can be useful for further research of low-lying isomeric transitions in 229Th isotope with energy of 7.8(0.5) eV

Electron Spectroscopy and the Electronic Structure of KNbO3: First Principle Calculations

Cataloged from PDF version of article.The electronic structures of KNbO(3)were calculated within the density functional theory, and their evolution was analyzed as the crystal-field symmetry changes from cubic to rhombohedral via tetragonal phase. We carried out electron-energy loss spectroscopy experiments by using synchrotron radiation and compared the results with the theoretical spectra calculated within Density Functional Theory. The dominant role of the NbO(6)octahedra in the formation of the energy spectra of KNbO(3)compound was demonstrated. The anomalous behavior of plasmons in ferroelectrics was exhibited by the function representing the characteristic energy loss in the region of phase transition

Energy States of Colored Particle in a Chromomagnetic Field

The unitary transformation, which diagonalizes squared Dirac equation in a constant chromomagnetic field is found. Applying this transformation, we find the eigenfunctions of diagonalized Hamiltonian, that describe the states with definite value of energy and call them energy states. It is pointed out that, the energy states are determined by the color interaction term of the particle with the background chromofield and this term is responsible for the splitting of the energy spectrum. We construct supercharge operators for the diagonal Hamiltonian, that ensure the superpartner property of the energy states.Comment: 25 pages, some calculation details have been removed, typos correcte

Coenzyme Q ₁₀ and L-Carnitine Disturbances in Children with Mitochondrial Diseases

Coenzyme Q10 (CoQ10) and L-carnitine are very important biologically active compounds involved in energy metabolism. L-carnitine and coenzyme Q10 disturbances in mitochondrial diseases require the correction. Patients and methods: The levels of coenzyme Q10 and L-carnitine (total carnitine, free carnitine, and acylcarnitines) were determined in children with mitochondrial diseases (25 children and 16 children, respectively). High-performance liquid chromatography with UV detection (chromatograph Shimadzu Nexera LC-30) and chromatography-mass spectrometry (Agilent 6410 QQQ , USA) were used. As an additional parameter of possible coenzyme Q10 and carnitine insufficiency, the coenzyme Q10/cholesterol ratio and acylcarnitines/free carnitine ratio were calculated. Results: A significantly low ratio of coenzyme Q10/cholesterol in children with mitochondrial diseases was revealed—0.10 ± 0.01 vs. 0.19 ± 0.01 in the control group (p < 0.001). A lower absolute level of coenzyme Q10 and tendency toward a more pronounced decrease in the Q10/cholesterol ratio in older patients (6–16 years) were shown. The free carnitine blood level was within the normal range and averaged at 29.8 ± 2.6 μmol/l; however, the level was lower than that in the control group (44 ± 5.2 μmol/l, p < 0.05). A pronounced significant increase in the acylcarnitines/free carnitine ratio was determined—1.5 ± 0.05 (the normal range < 0.6)

Scientific breeding of winter bread wheat in the Non-Сhernozem zone of Russia: the history, methods and results

The article describes the main stages and achievements of the breeding of winter bread wheat (Triticum aestivum L.) in the Non-Chernozem zone for more than a century. The beginning of breeding work was laid by D.L. Rudzinsky on the experimental field of the Moscow Agricultural Institute. Beginning from the 1940s, under the leadership of Academician N.V. Tsitsin, and then Prof. G.D. Lapchenko, the method of distinct hybridization with blue wheatgrass (Agropyron glaucum (Desf. ex DC.) Roem. &amp; Schult.) was actively used. The resulting wheat-wheatgrass hybrids had an average winter hardiness, increased grain quality and productivity. Cultivar Zarya developed in the 1970s (by individual selection from the F3 cross combination of cv. Mironovskaya 808 × line 126/65 (in the pedigree of this line, there is a wheat-wheatgrass hybrid PPG 599)) had a high yield and was widely used in further crosses. In the 1980s, Academician B.I. Sandukhadze achieved a significant increase in yield by using the method of intermittent backcrosses due to the producing of varieties with a new morphoecotype (cvs Inna, Pamyati Fedina, etc.), namely, winter-hardy, short stemmed (dwarf), and productive. Cultivar Moskovskaya 39 (registration in 1999) was referred to strong wheat, with a stable protein content of 15–16 %, gluten 30–35 %. Produced in the 2000s, cvs Moskovskaya 56, Nemchinovskaya 57, Galina, Nemchinovskaya 24, Nemchinovskaya 17, and Moskovskaya 40 have a high adaptability to the environment of the region; give a high yield and quality of grain. The area of crops of these cultivars in Russia occupies more than 2 million ha. The current trends in wheat breeding are indicated, the production yield of commercial cultivars of breeding by the Federal Research Center “Nemchinovka”over 12.0 tons per ha and the protein content in the grain up to 17 % are shown. As a result of succession, originality and application of the methodology of scientific breeding, the yield of winter bread wheat in the period from the beginning of the last century to the present has increased from 1.0 to 12.0 and more tons per ha

Complex-Radical Terpolymerization of Maleic Anhydride (Styrene), Allyl Propionate and Methyl Methacrylate

The radical terpolymerization reactions of the acceptor-donor-acceptor and donor-acceptor-donor systems, maleic anhydride (MA)-allyl propionate (AP)-methyl methacrylate (MMA) and styrene (St)-MMA-AP, had been studied. The terpolymerizations were carried out in methyl ethyl ketone at 60-75 °C in the presence of 2,2’-azoisobutyronitrile (ABIN) used as the initiator. Some kinetic parameters and copolymerization constants - for both, system were determined by dilatometric and Kelen-Tudos or Seiner-Lift methods. The obtained results are discussed in terms of the free monomer and complex chain growth models. It is shown that terpolymerization was carried out at a stage close to binary copolymerization of MA...AP complex with free MMA and St...MMA complex with AP in the both studied system, respectively. These systems are also used as model for interpretation of cyclocopolymerization mechanism in allyl methactylate-MA (or St) system. DTA and TGA analyses indicated the relatively high thermal stability of St-MMA-AP terpolymer. It is shown that this terpolymer decomposes through a one-step reaction at 310 °C, however MA-AP-MMA terpolymer decomposes through a multi-step reactions at 150, 260 and 310 °C

Structure, bonding and morphology of hydrothermally synthesised xonotlite

The authors have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically prepared, semicrystalline phase with Ca/Si=1, the authors have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250 degrees C. Analysis in each case was by X-ray photoelectron spectroscopy, environmental scanning electron microscopy and X-ray diffraction. The authors’ use of a much lower water/solid ratio has indirectly confirmed the ‘through solution’ mechanism of xonotlite formation, where silicate dissolution is a key precursor of xonotlite formation. Concerning the role of temperature, too low a temperature (~200 degrees C) fails to yield xonotlite or leads to increased number of structural defects in the silicate chains of xonotlite and too high a temperature (>250 degrees C) leads to degradation of the xonotlite structure, through leaching of interchain calcium. Synthesis duration meanwhile leads to increased silicate polymerisation due to diminishing of the defects in the silicate chains and more perfect crystal morphologies