952 research outputs found
The adaptation challenges of foreign students in TPU from the perspective of cross-cultural communication
The goal of Russian universities is to join the international scientific community. This aim is closely connected with the attraction of foreign students to study in Russia. TPU is one of the greatest centres to attract foreign students in our region. There are different programs of the adaptation to life in Tomsk and university life for foreign students. For our research it was important to learn about the features of the adaptation of foreign students who are away from home. We held a survey with 22 foreign students. In our research we identified important problems faced by foreign students: problem with communication; the problem of isolation living in separate hostels and studying; climate component in the process of the adaptation. In conclusion, we can say that Tomsk can be considered prosperous and hospitable zone for foreign students. Задача российских вузов - выйти в международное пространство и прочно утвердиться в нем. Эта цель тесно связана с привлечением иностранных студентов для обучения в России. ТПУ представляет собой один из крупнейших центров по привлечению иностранных студентов в своем регионе. Для иностранных студентов университетом предусматриваются различные программы адаптации к жизни в городе и к университетской жизни. Для нашей работы представлялось важным узнать об особенностях адаптации иностранных студентов, находящихся вдали от дома. Мы провели анкетирование 22 иностранных студентов. В нашей работе по опросу были выявлены важные проблемы, с которыми сталкиваются иностранные студенты: проблема с коммуникацией; проблема социальной замкнутости: отдельное проживание и обучение; климатическая составляющая процесса адаптации. В заключение мы можем сказать, что Томск может считаться процветающей и гостеприимной зоны для иностранных студентов
Electrodeposition of Silicon from Molten KCl-K2SiF6for Lithium-Ion Batteries
In this paper we report characteristics and electrochemical properties of silicon fibers used as lithium-ion battery anode. All samples were synthesized by potentiostatic electrodeposition from molten KCl K2SiF6. From molten KCl CsCl K2SiF6 deposition was carried out in galvanostatic mode. Despite the synthesis in inert atmosphere and absence of oxygen containing compounds in the melt resulting silicon after washing contains at least 15 at% oxygen. Silicon fibers synthesized at ?250 mV (vs Si) were the thinnest with diameter as small as 100 nm; average fiber length increased with increasing overvoltage. Addition of CsCl to the melt results in decrease of the average fibers diameter. Silicon fibers synthesized at ?250 mV (vs Si) in KCl K2SiF6 melt showed the best cycling performance with capacity of 1030 mAh g?1 at 0.2 A g?1 discharge current and capacity of 715 mAh g?1 after 10 cycles. Lithium diffusion coefficients calculated from galvanostatic intermittent titration technique (GITT) are common for silicon-based anode. The highest initial diffusion coefficient value of 6.68 10?11 cm2 s?1 was achieved for silicon synthesized from melt with addition of CsCl. Low capacity and rapid capacity fading for all samples can be caused by high silicon dioxide content, further treatment of synthesized silicon is necessary to achieve higher performance. © 2022 The Author(s).This work is performed in the frame of the State Assignment number 075-03-2022-011 dated 14.01.2022 (the theme number FEUZ-2020-0037)
Electrochemical Synthesis of Nano-sized Silicon from KCI–K2SiF6 Melts for Powerful Lithium-Ion Batteries
Currently, silicon and silicon-based composite materials are widely used in microelectronics and solar energy devices. At the same time, silicon in the form of nanoscale fibers and various particles morphology is required for lithium-ion batteries with increased capacity. In this work, we studied the electrolytic production of nanosized silicon from low-fluoride KCl–K2SiF6 and KCl–K2SiF6–SiO2 melts. The effect of SiO2 addition on the morphology and composition of electrolytic silicon deposits was studied under the conditions of potentiostatic electrolysis (cathode overvoltage of 0.1, 0.15, and 0.25 V vs. the potential of a quasi-reference electrode). The obtained silicon deposits were separated from the electrolyte residues, analyzed by scanning electron microscopy and spectral analysis, and then used to fabricate a composite Si/C anode for a lithium-ion battery. The energy characteristics of the manufactured anode half-cells were measured by the galvanostatic cycling method. Cycling revealed better capacity retention and higher coulombic efficiency of the Si/C composite based on silicon synthesized from KCl–K2SiF6–SiO2 melt. After 15 cycles at 200 mA·g−1, material obtained at 0.15 V overvoltage demonstrates capacity of 850 mAh·g−1 . © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This research received no external funding. This work is performed in the frame of the State Assignment number 075-032020-582/1, dated 18 February 2020 (the theme number 0836-2020-0037)
Achieving High Spin-Flip Efficiency with an RF Magnet and Discovery of Spin-Resonance Strength Formulae Problem.
Frequent polarization reversals, or spin-flips, of a beam in high energy storage rings, may be a powerful tool for greatly reducing the systematic errors of spin asymmetry measurements in scattering experiments. A spin-flipping technique using an artificially induced spin-depolarizing resonance, created by an rf magnet with a horizontal magnetic field, is being developed to allow such polarization reversals in a well-controlled way. We used a new ferrite rf dipole to study the spin flipping of a 2.1 GeV/c vertically polarized proton beam stored in the COSY Cooler Synchrotron in Jϋlich, Germany. We swept the rf dipole's frequency through an rf-induced spin resonance to flip the beam's polarization direction. After determining the resonance's frequency, we varied the frequency's range and ramp time, and the number of flips. At the rf dipole's maximum strength and its optimum frequency range and ramp time, we measured a proton spin-flip efficiency of 99.92 ± 0.04 %. This result, along with previous similar IUCF results at lower energy, indicate that due to the Lorentz invariance of an rf-dipole's transverse ∫Bdl and the weak energy dependence of its spin-resonance strength, a small rf dipole should allow efficient spin flipping in very high energies in rings such as the 250 GeV RHIC or even the 7 TeV LHC.
The accurate prediction of a spin-depolarizing resonance strength remains a challenge. We earlier analyzed all available data on the spin-flipping of stored beams of polarized protons, electrons and deuterons. We found 10-20-fold deviations of the measured rf-induced resonance strength from the theoretically predicted strength. Therefore, we recently studied these resonance strength deviations experimentally by varying the rf dipole's voltage, and the size, momentum spread and vertical betatron tune with a 2.1 GeV/c polarized proton beam stored in COSY. We found no dependence of the resonance strength on the beam's size or momentum spread. We did find enhancements of more than 100 when the rf spin resonance was near an intrinsic proton spin resonance.
We studied the resonance strength deviations experimentally by using 1.85 GeV/c vertically polarized deuterons stored in COSY with an rf dipole and then an rf solenoid.Ph.D.PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/60881/1/leonova_1.pd
Orientation, substructure, and optical properties of rutile films
The orientation, optical properties, and substructure of rutile films prepared by thermal and pulsed photon assisted oxidation of single crystal Ti films were investigated by transmission electron micros copy, optical spectroscopy, and high energy electron diffractionyesBelgorod State Universit
Geotechnical properties of gullying in Tomsk Oblast
The article deals with causes, conditions and factors of gullying in Tomsk Oblast, the case of site Grodnenskaya. A nuclear-power station was planned to be constructed in Closed Administrative Territorial Unit Seversk, which led to geotechnical investigation of the area to study the geological processes developing there. The investigation included reconnaissance traverse of the area, geological and geomorphic descriptions, and sampling. The area and percentage of the territory affected by the geological processes were estimated. As a result, it was proved that the geological processes of the area are conditioned by surface water activity leading to gullying and river erosion, and by both ground water and surface water activity resulting in bog formation. It appears that gullying is caused not only by natural factors but also by technogenic ones
Structural And Extremal Properties of the Hot Rolling Batches Precedence Graph
In this paper we study structural properties and properties of maximal paths of the hot rolling batches precedence graph. The hot rolling batches precedence graph arises in the problem of planning and scheduling of a hot strip mill load. Slab batches are selected and sequenced in turns. Basic technological restrictions on batch sequencing in turns are represented by the rolling batches precedence graph. Some fundamental structural properties of this graphs are stated such as the local block structure and the maximal paths structure. Motivation and overview of the result application potential are also provided
- …