434 research outputs found
Optical Absorption and Raman Spectroscopy Study of the Fluorinated Double-Wall Carbon Nanotubes
Double-wall carbon nanotube (DWNT) samples have been fluorinated at room temperature with varied concentration of a fluorinating agent BrF3. Content of the products estimated from X-ray photoelectron data was equal to CF0.20 and CF0.29 in the case of deficit and excess of BrF3. Raman spectroscopy showed considerable decrease of carbon nanotube amount in the fluorinated samples. Analysis of optical absorption spectra measured for pristine and fluorinated DWNT samples revealed a selectivity of carbon nanotube fluorination. Nanotubes with large chiral angle are more inert to the fluorinating agent used
Manifestation of local polar regions in spectroscopic investigations in ferroelectrics and relaxors
The reported study was funded by RFBR according to the research project 18-02-00399 and State assignment No AAAA-A17-117052410033-9. Experiments were performed in the multiple-access center “High-Resolution Spectroscopy of Gases and Condensed Matter” in IA&E SBRAS (Novosibirsk, Russia)
The investigation of the time characteristic of local polar inhomogeneities in paraelectric phase in relaxors and ferroelectric crystals: on the example of SrxBa1-xNb2O6 crystals with different chemical composition
The reported study was funded by RFBR according to the research projects No. 18-02-00399 and State assignment No AAAAA17-117052410033-9. The experiments were performed in the multiple-access center “High-Resolution Spectroscopy of Gases and Condensed Matter” in IA&E SBRAS (Novosibirsk, Russia)
Algorithm and performance of a clinical IMRT beam-angle optimization system
This paper describes the algorithm and examines the performance of an IMRT
beam-angle optimization (BAO) system. In this algorithm successive sets of beam
angles are selected from a set of predefined directions using a fast simulated
annealing (FSA) algorithm. An IMRT beam-profile optimization is performed on
each generated set of beams. The IMRT optimization is accelerated by using a
fast dose calculation method that utilizes a precomputed dose kernel. A compact
kernel is constructed for each of the predefined beams prior to starting the
FSA algorithm. The IMRT optimizations during the BAO are then performed using
these kernels in a fast dose calculation engine. This technique allows the IMRT
optimization to be performed more than two orders of magnitude faster than a
similar optimization that uses a convolution dose calculation engine.Comment: Final version that appeared in Phys. Med. Biol. 48 (2003) 3191-3212.
Original EPS figures have been converted to PNG files due to size limi
Analysis of the possibilities of using petroleum coke in various industries
In this article, work has been done on the study and comparison of forecasting methods, namely the methods: ARIMA, LSTM, Facebook Prophet. Examples of the work of these methods are given, and the best one for the implementation of the "Forecast of natural gas consumption in Belarus" is selected
Analysis of the possibilities of using petroleum coke in various industries
In this article, work has been done on the study and comparison of forecasting methods, namely the methods: ARIMA, LSTM, Facebook Prophet. Examples of the work of these methods are given, and the best one for the implementation of the "Forecast of natural gas consumption in Belarus" is selected
Parity Effect and Charge Binding Transition in Submicron Josephson Junction Arrays
We reconsider the issue of Berezinskii-Kosterlitz-Thouless (BKT) transition
into an insulating state in the Coulomb-dominated Josephson junction arrays. We
show that previously predicted picture of the Cooper-pair BKT transtion at T =
T_2 is valid only under the condition that T_2 is considerably below the
parity-effect temperature (which is usually almost 10 times below the value of
superconductive transition temperature), and even in this case it is not a
rigorous phase transition but only a crossover, whereas the real phase
transition takes place at T_1 = T_2/4. Our theory is in agreement with
available experimental data on Coulomb-dominated Josephson arrays and also
sheds some light on the origin of unusual reentrant temperature dependence of
resistivity in the array with nearly-criticial ratio of Coulomb to Josephson
energies.Comment: 4 pages, Revtex, to be published in JETP Letters, April 9
Characterization of Ni-Cd Nanostructured System Obtained by Chemical Reduction of Salts
The process of obtaining of highly dispersed metal powders of Ni-Cd system by reduction of their salts by hydrazine in aqueous medium at high alkalinity was investigated. The possibility of production metal powders containing up to 50 mol% of cadmium is established and conditions for their synthesis are optimized. Phase composition, structural parameters, dispersity of solid products during the reduction
process were studied by X-ray diffraction (XRD) and SAXS. The formation of metal solid solutions with FCC lattice contradicts to the known phase diagram for Ni-Cd and may be explained by increasing the energy of the particles in the nanostate. The formation of intermetallide NiCd5 in the studied compositions area is caused by sequential character of reduction process; as a result the metal product on the initial stage of reduction is significantly enriched with cadmium
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