bluuebunny/crossref_metadata_2025 huggingface dataset:
Faktor Penghambat Studi Mahasiswa yang Tidak Lulus Tepat Waktu di Jurusan Pendidikan Teknik Mesin FT UNY
Authors: Widarto Widarto
Published: December 2017

The study aimed to identify the students who cannot finish their course on time, addressing the inhibiting factor for their course completion, identify the students’ efforts and struggle on their course completion, and to understand their expectations from the school administration to accommodate their course completion. The research used survey methods with questionnaire as the instrument. The subjects of the research are the diploma and bachelor degree students of Mechanical Engineering Education Department. Data were analyzed using quantitative-descriptive technique. The results show that the inhibiting factors are the long commute to campus for supervisions, many students still taking coursework, students already have a job, passive supervisors, unconducive environment, and supervisions that were not intensively done. The students were still committed to complete their course, albeit those inhibiting factors. Students’ commitments were supported by various efforts, namely intensive supervision, independent study or discussion, and finding a conducive environment to work on their final projects and theses. Students’ expectations for the success of their course are the availability of final project and thesis in an earlier stage of their study, supervisor should be appointed based on their competency, increasing the allocated time of the final project schedule, the administration needs to renew the workshop’s machinery and equipment, and cut off the unnecessary final project and Thesis administration steps, to make it easier for students in completing their course. Tujuan penelitian adalah untuk mengidentifikasi mahasiswa yang tidak dapat menyelesaikan studinya tepat waktu, mengetahui faktor penghambat, mengetahui usaha-usaha yang sudah dilakukan mahasiswa, dan mengetahui harapan mahasiswa kepada pengelola Jurusan Pendidikan Teknik Mesin FT UNY. Penelitian menggunakan metode survey menggunakan angket dengan analisis deskriptif kuantitatif. Objek penelitian yaitu mahasiswa D3 Teknik Mesin dan S1 Pendidikan Teknik Mesin. Hasil penelitian menunjukkan terdapat beberapa kendala penyelesaian studi yaitu: jarak yang jauh ke kampus untuk bimbingan, masih ada yang kuliah teori/praktik, sudah ada yang bekerja, dosen kurang aktif membimbing, lingkungan tempat tinggal kurang kondusif, dan bimbingan tidak intensif. Namun demikian, mahasiswa masih berkomitmen untuk menyelesaikan studinya. Keseriusan mahasiswa tersebut didukung dengan berbagai usaha, seperti bimbingan secara intensif, belajar mandiri atau diskusi, dan mencari lingkungan yang kondusif untuk mengerjakan Proyek Akhir dan Skripsi. Selain itu, harapan mahasiswa yaitu mata kuliah Proyek Akhir dan Skripsi dapat diambil lebih awal, penentuan dosen pengampu mata kuliah relevan dengan kompetensinya, jadwal pelaksanaan Proyek Akhir perlu ditambah frekwensinya, peremajakan peralatan bengkel, dan memperpendek administrasi Proyek Akhir dan Skripsi sehingga semakin mempermudah mahasiswa menyelesaikan studinya.
The effects of the Mediterranean Diet on Chronic Diseases: Cardiovascular Diseases, Oxidative Stress, Dyslipidemia, Diabetes Mellitus, Blood Pressure, Cancer, Neurodegenerative Disease and Obesity
Authors: Benyaich Abdelhay
Published: December 2017

Poor dietary habits lead to the emergence of chronic diseases such as coronary heart disease, stroke, hypertension, diabetes mellitus, dyslipidemia, cancer, dementia, obesity and oxidative stress involved through the aggression of cells by free radicals, Knowing that these diseases cause a global burden both individually and economically, Several studies focus on the relationship between diet and chronic disease. Studies suggest that the Mediterranean diet, (MD) traditional eating habits and lifestyle specific to the Mediterranean region, reduce the incidence of chronic diseases and improve longevity. The MD is known to be one of the healthiest diets, this diet is based on herbs, spices, vegetables, fruits, olive oils, cereals (preferably whole grains), legumes and nuts, fish and shellfish, white meat, so the main source of dietary fat from MD is olive oil. Moderate consumption of eggs and dairy products, and reduced consumption of red meats, processed meats and foods rich in sugars and fats. MD has a beneficial fatty acid profile with a higher content of monounsaturated fatty acids (MSFA) and a higher MSFA / saturated fatty acid (SFA) ratio than non-Mediterranean diets. High consumption of dietary fiber. a low glycemic index, anti-inflammatory effects, and antioxidant compounds, can work together to produce favorable effects on health status. MD is rich in vitamins and minerals, such as: vitamin B (B1, B2, niacin, B6, folate and B12) and antioxidant vitamins (vitamins E and C), and polyphenol, flavonoids, phytosterols, n-fatty acids 3 (alpha linoleic acid), resveratrol, quercetin, oleic acid, carotenoids and lutein. The purpose of this review is to provide an update on the current state of science regarding the relationship between the traditional Mediterranean diet and lifestyle related chronic diseases, and discuss the mechanisms involved and opportunities. in this area of research, to clarify and increase the confidence of the role of nutrition in the etiology of chronic diseases.
XXI Международный симпозиум Нанофизика и наноэлектроника", Нижний Новгород, 13-16 марта 2017 г. Нитевидные нанокристаллы GaP/Si (111), синтезированные методом молекулярно-пучковой эпитаксии с переключением гексагональной и кубической фазy -=SUP=-*-=/SUP=-
Authors: Штром И.В. , Сибирев Н.В. , Убыйвовк Е.В. , Самсоненко Ю.Б. , Хребтов А.И. , Резник Р.Р. , Буравлев А.Д. , Цырлин Г.Э.
Published: December 2017

AbstractA theoretical and experimental description of the synthesis of GaP nanowire crystals by molecularbeam epitaxy on Si(111) substrates with the use of gold as a catalyst is presented. The ratio between the fluxes of materials to be deposited and the substrate temperature are varied for a short time during nanowire synthesis in order to analyze the possibility of producing nanoinclusions of different polytypes. It is established that variations in the ratio between the fluxes of materials to be deposited and in the growth temperature bring about the controllable formation of inclusions, among them are structurally cubic crystalline regions. The inclusions are several nanometers thick.
Эффективная масса и g-фактор электронов в широких квантовых ямах теллурида ртути -=SUP=-*-=/SUP=-
Authors: Гудина С.В. , Неверов В.Н. , Ильченко Е.В. , Боголюбский А.С. , Харус Г.И. , Шелушинина Н.Г. , Подгорных С.М. , Якунин М.В. , Михайлов Н.Н. , Дворецкий С.А.
Published: December 2017

AbstractThe magnetic-field (0 T < B < 9 T) dependence of the longitudinal and Hall resistances at fixed temperatures (2 K < T < 50 K) for the HgCdTe/HgTe/HgCdTe system with a HgTe quantum well 20.3 nm in width are measured. The activation analysis of the magnetoresistance curves is used as a tool for identifying the mobility gaps between neighboring Landau levels. The activation-energy values obtained from the temperature dependences of the longitudinal resistance in the plateau regions of the quantum Hall effect with the filling factors ν = 1, 2, 3 make it possible to estimate the effective mass and the g factor of electrons in the system under study. Indications concerning the possibility of large values of the g factor (≅ 80) are obtained.
Сверхбыстрая динамика электронно-дырочной плазмы в полупроводниковых нитевидных нанокристаллах -=SUP=-*-=/SUP=-
Authors: Трухин В.Н. , Буравлев А.Д. , Мустафин И.А. , Цырлин Г.Э. , Kakko J.P. , Lipsanen H.
Published: December 2017

AbstractExperimental results obtained in a study of the effect of electron–hole plasma on the generation of terahertz (THz) radiation in semiconductor nanowires grown by metal-organic vapor-phase epitaxy (MOVPE) are presented. It is shown that the temporal dynamics of photoexcited charge carriers in semiconductor nanowires is determined by the transport of carriers, both electrons and holes, and by the time of capture of electrons and holes at surface levels.
Влияние гидростатического давления на статическую диэлектрическую проницаемость германия
Authors: Мусаев А.М.
Published: December 2017

AbstractThe dependence of the static permittivity of single-crystal germanium on hydrostatic pressure up to P ≈ 7.4 GPa is studied experimentally. As the pressure is increased to P ≈ 4 GPa, the permittivity of Ge decreases by a factor of ~13 to ε = 1.22. As the pressure is increased further to P ≈ 7 GPa, a moderate increase in ε to the initial value is observed. In the range 7–7.4 GPa, the permittivity increases to a value larger than 1000. The experimental dependences obtained in the study substantially differ from the previously known dependences.
Спектры инфракрасного отражения пленок топологического изолятора Pb-=SUB=-1-x-=/SUB=-Sn-=SUB=-x-=/SUB=-Se (x=0.2, 0.34) на подложке ZnTe/GaAs и колебательные моды многослойных структур
Authors: Новикова Н.Н. , Яковлев В.А. , Кучеренко И.В. , Виноградов В.С. , Алещенко Ю.А. , Муратов А.В. , Karczewski G. , Chusnutdinow S.
Published: December 2017

AbstractThe reflectance spectra of the topological insulator Pb_1– x Sn_ x Se ( x = 0.2, 0.34) films grown by molecular-beam epitaxy on a ZnTe/GaAs substrate are measured in the range of 12–2500 cm^–1 at room temperature. Using dispersion analysis, the frequencies of transverse optical phonons, plasma frequencies, highfrequency permittivities, and layer thicknesses are determined. In the quasi-steady-state approximation, the interface mode frequencies of the four-layer structure are calculated as a function of the overlap parameter χ_1 (0 ≤ χ_1 ≤ 1). The parameter describes the degree of overlap of two interface modes localized at planes bounding the layer to the right and left. The existence of interacting interface modes in the structure makes its spectrum different from the sum of component spectra. These differences manifest themselves in the experiment. The conditions of the interaction of interface modes with IR radiation are discussed.
Подвижность двумерного электронного газа в DA-pHEMT гетроструктурах с различной шириной профиля delta-n-слоев
Authors: Протасов Д.Ю. , Бакаров А.К. , Торопов А.И. , Бер Б.Я. , Казанцев Д.Ю. , Журавлев К.С.
Published: December 2017

AbstractThe effect of the silicon-atom distribution profile in donor δ-layers of AlGaAs/InGaAs/AlGaAs heterostructures with donor–acceptor doping on the mobility of the two-dimensional electron gas is studied. The parameters of the δ-layer profiles are determined using the normal approximation of the spatial distributions of silicon atoms, measured by secondary-ion mass spectroscopy. It is shown that the standard deviation σ of the δ-layer profile can be reduced from 3.4 to 2.5 nm by the proper selection of growth conditions. Measurements of the magnetic-field dependences of the Hall effect and conductivity show that such a decrease in σ allowed an increase in the mobility of the two-dimensional electron gas in heterostructures by 4000 cm^2/(V s) at 77 K and 600 cm^2/(V s) at 300 K. The mobility calculation taking into account filling of the first two size-quantization subbands shows that an increase in the mobility is well explained by a reduction in the Coulomb scattering at ionized donors due to an increase in the effective thickness of the spacer layer with decreasing σ of the δ-layer profile.
Поглощение излучения дальнего инфракрасного диапазона квантовыми точками Ge/Si
Authors: Софронов А.Н. , Балагула Р.М. , Фирсов Д.А. , Воробьев Л.Е. , Тонких А.А. , Саркисян А.А. , Айрапетян Д.Б. , Петросян Л.С. , Казарян Э.М.
Published: December 2017

AbstractThe experimental and theoretical results of studies of optical absorption in doped Ge/Si quantumdot structures in the far-infrared region, corresponding to the energies of transitions of holes from the ground state to the lowest excited size-quantization state, are reported. An analytical theory of the size quantization of holes in a lens-shaped quantum dot is developed in the context of the adiabatic approximation with consideration for pair Coulomb interaction. It is shown that the interaction has no effect on the frequencies of lower interlevel resonances. This fact is representative of generalized Kohn’s theorem satisfied due to the specific geometric shape of the quantum dot. The experimental and theoretical values of the transition energies are in good agreement.
Электретный эффект в композитах полимер-сегнетопьезокерамика с различной электроотрицательностью полимерной матрицы и катионов пьезофазы
Authors: Курбанов М.А. , Рамазанова И.С. , Дадашев З.А. , Юсифова У.В. , Гусейнова Г.Х. , Азизова К.К. , Фараджзаде И.А.
Published: December 2017

AbstractThe influence of the electronegativity of phases, which is controlled by composite crystallization under the conditions of the effect of the electric discharge and covalence of piezophase cations, on the formation mechanism of the stable electret effect is determined. The specific features of the formation of the electret effect in composites based on polyolefins (HDPE, PP), fluorine-containing polymers (F42), and ferroelectric piezoelectric ceramics of the family of lead zirconate–titanate (Pb(Zr,Ti)O_3) crystallized under conditions of the effect of electric discharge plasma, are revealed. A physical model of electret composites taking into account the role of homocharges and heterocharges formed in a composite by its dispersion with piezoceramic particles of various structures—rhombohedral, tetragonal, and heterogeneous—is proposed.
Особенности свойств полупроводников А-=SUP=-III-=/SUP=-В-=SUP=-V-=/SUP=- в мультизеренной наноструктуре
Authors: Жуков Н.Д. , Кабанов В.Ф. , Михайлов А.И. , Мосияш Д.С. , Хазанов А.А. , Шишкин М.И.
Published: December 2017

AbstractThe systematized results of studies of the properties of InAs, InSb, and GaAs semiconductors in a multigrain structure based on measurement and analysis of the current–voltage and spectral characteristics are presented. It is established that electron emission and injection are determined by the localization effects of states in the bulk and surface region of submicron grains. The phenomena of current limitation and lowfield emission characteristic of quantum dots are revealed and studied. The results can be used in studies and in the development of multigrain structures for gas and optical sensors, detectors, and emitters of infrared and terahertz ranges.
Изучение сверхструктуры в сильно легированном пористом фосфиде индия рентгеновскими методами
Authors: Бойко М.Е. , Шарков М.Д. , Карлина Л.Б. , Бойко А.М. , Конников С.Г.
Published: December 2017

AbstractAn indium-phosphide InP sample subjected to the pore-generation procedure and then doped with S atoms is studied by the methods of X-ray diffraction analysis (XRD) and small-angle X-ray scattering (SAXS) (with Cu K _α1-radiation). The XRD data demonstrate that the sample consists of (coherent) aligned homogeneous components. A point detector is used to obtain, in the anomalous transmission mode by Borrmann, a set of SAXS curves at sample positions varied by azimuthal rotations. The SAXS data are used to simulate a 2D SAXS pattern for the sample under study, which makes it possible to determine the long-distance translation symmetry and, consequently, the presence of a superstructure. The interplanar distances in the superstructure in the directions (110) and (1 0) of the InP lattice are found to be ~260 and 450 nm, respectively. The symmetry group of the superstructure is determined as C _2 v in the (001) plane of the sample lattice.
Двухконтактные тандемные солнечные элементы DSC/c-Si: оптимизация параметров фотоэлектрода на основе диоксида титана
Authors: Никольская А.Б. , Вильданова М.Ф. , Козлов С.С. , Шевалеевский О.И.
Published: December 2017

AbstractNew types of two-terminal tandem solar cells DSC/ c -Si in which mesoscopic dye-sensitized solar cell (DSC) was connected in parallel with a crystalline silicon ( c -Si) solar cell, were developed and investigated. We have measured the optical and photovoltaic parameters for both the individual and the fabricated tandem DSC/ c -Si solar cells. It was shown that the highest efficiency of 14.7% for the tandem DSC/ c -Si solar cell under standard AM1.5G (100 mW/cm^2) illumination conditions was achieved for DSC based on 3.5 μm thick titanium dioxide photoelectrode.
Ширина линии излучения и alpha-фактор одномодовых вертикально-излучающих лазеров спектрального диапазона 850 нм на основе квантовых ям InGaAs/AlGaAs -=SUP=-*-=/SUP=-
Authors: Блохин С.А. , Бобров М.А. , Блохин А.А. , Кузьменков А.Г. , Васильев А.П. , Задиранов Ю.М. , Европейцев Е.А. , Сахаров А.В. , Леденцов Н.Н. , Карачинский Л.Я. , Оспенников А.М. , Малеев Н.А. , Устинов В.М.
Published: December 2017

AbstractThe emission-line width for 850-nm single-mode vertical-cavity surface-emitting lasers based on InGaAs/AlGaAs quantum wells is studied. The width of the emission line for a laser with a 2-μm oxide current aperture attains it minimum (~110 MHz) at an output power of 0.8 mW. As the optical output power is further increased, anomalous broadening of the emission line is observed; this is apparently caused by an increase in the α-factor as a result of a decrease in the differential gain in the active region under conditions of increased concentration of charge carriers and of high internal optical losses in the microcavity. The α-factor is estimated using two independent methods.
О пространственной локализации свободных электронов в n-канальных МОП-транзисторах на основе 4H-SiC
Authors: Иванов П.А.
Published: December 2017

AbstractThe problem of the spatial localization of free electrons in 4 H -SiC metal—oxide—semiconductor field effect transistors (MOSFETS) with an accumulation- and inversion-type n channel is theoretically analyzed. The analysis demonstrates that, in optimally designed accumulation transistors (ACCUFETs), the average distance from the surface, at which free electrons are localized, may be an order of magnitude larger than that in inversion MOSFETs. This can make 4 H -SiC ACCUFETs advantageous as regards the effective carrier mobility in a conducting channel.
Исследование структуры объемного гетероперехода в полимерных солнечных элементах с помощью комбинации ультрамикротомирования и атомно-силовой микроскопии
Authors: Алексеев А.М. , Ал-Афееф A. , Хедли Г.Д. , Харинцев С.С. , Ефимов А.Е. , Едрисов А.Т. , Дюжев Н.А. , Самуэль И.Д.В.
Published: December 2017

AbstractA method for visualization via atomic-force microscopy of the internal structure of photoactive layers of polymer solar cells using an ultramicrotome for photoactive layer cutting is proposed and applied. The method creates an opportunity to take advantage of atomic-force microscopy in structural investigations of the bulk of soft samples. Such advantages of atomic-force microscopy include a high contrast and the ability to measure various surface properties at nanometer resolution. Using the proposed method, samples of the photoactive layer of polymer solar cells based on a mixture of PTB7 polythiophene and PC_71BM fullerene derivatives are studied. The disclosed details of the bulk structure of this mixture allow us to draw additional conclusions about the effect of morphology on the efficiency of organic solar cells.
Влияние разориентации подложки на состав, структурные и фотолюминесцентные свойства эпитаксиальных слоев, выращенных на GaAs(100)
Authors: Середин П.В. , Леньшин А.С. , Федюкин А.В. , Арсентьев И.Н. , Жаботинский А.В. , Николаев Д.Н. , Leiste Harald , Rinke Monika
Published: December 2017

AbstractThe influence of the degree of misorientation and treatment of a GaAs substrate on the structural and optical characteristics of homoepitaxial GaAs/GaAs(100) structures grown by metal–organic chemicalvapor deposition is studied. From the data obtained by a series of structural and spectroscopic techniques, it is shown that the degree of deviation of the substrate from the exact orientation towards the [110] direction by an angle of up to 4° brings about stepwise growth of the GaAs film in the initial stage and a further increase in the degree of misorienration towards the [110] direction to 10° results in an increase in the number of structural defects in the epitaxial film. At the same time, the samples of homoepitaxial structures grown by metal–organic chemical-vapor deposition on GaAs(100) substrates misoriented by 4° towards the [110] direction possess the highest photoluminescence efficiency; it is ~15% higher than the corresponding quantity for structures grown on precisely oriented GaAs(100) substrates. Preliminary polishing of the GaAs substrate (removal of an oxide layer) also yields the intensification of photoluminescence emission compared to emission in the case of an unpolished substrate of the same type. For samples grown on substrates misoriented by 4°, such an increase in the photoluminescence efficiency is ~30%.
Исследование структуры нитевидных нанокристаллов сульфида кадмия, синтезированных методом вакуумного испарения и конденсации в квазизамкнутом объеме
Authors: Беляев А.П. , Антипов В.В. , Рубец В.П.
Published: December 2017

AbstractThe results of crystallinity studies of an ensemble of cadmium-sulfide nanowire crystals synthesized from the vapor phase in a quasi-closed volume are reported. The nanowires are from 10 nm to several micrometers in diameter and tens of millimeters in length. Electron diffraction and luminescence are studied. The diffraction patterns and micrographs are presented. The results suggest a high degree of crystallinity of the nanowires.
Оптимизация структурных свойств и морфологии поверхности метаморфного буферного слоя In-=SUB=-x-=/SUB=-Al-=SUB=-1-x-=/SUB=-As с корневым профилем изменения состава (x=0.05-0.83), выращиваемого методом молекулярно-пучковой эпитаксии на GaAs (001)
Authors: Соловьев В.А. , Чернов М.Ю. , Ситникова А.А. , Брунков П.Н. , Мельцер Б.Я. , Иванов С.В.
Published: December 2017

AbstractThe results of optimization of the design and growth conditions of an In_ x Al_1– x As metamorphic buffer layer with a high In content ( x = 0.05–0.83) grown via MBE on GaAs(001) substrates with the purpose of optimizing its surface morphological characteristics and structural properties and lowering the surface density of threading dislocations. The lowest surface-pattern roughness RMS = 2.3 nm (on an area of 10 × 10 μm) and density of threading dislocations of 5 × 10^7 cm^–2 are found in the samples with a convex-graded metamorphic buffer layer.
Исследование модифицированной структуры квантового каскадного лазера
Authors: Мамутин В.В. , Малеев Н.А. , Васильев А.П. , Ильинская Н.Д. , Задиранов Ю.М. , Усикова А.А. , Яговкина М.А. , Шерняков Ю.М. , Устинов В.М.
Published: December 2017

AbstractThe process of obtaining a modified structure for quantum cascade lasers is studied; this process includes growth using molecular-beam epitaxy, plasma etching, photolithography with the use of liquid etching, and the formation of special contacts for decreasing losses in the waveguide. The use of a special type of structure makes it possible, even without postgrowth overgrowth with a high-resistivity material, to attain parameters satisfying requirements to heterostructures in high-quality quantum cascade lasers at maximal simplification of the entire preparation process.
Новый механизм реализации омических контактов
Authors: Саченко А.В. , Беляев А.Е. , Конакова Р.В.
Published: December 2017

AbstractAnalysis of the contact-barrier height taking into account the distribution of surface states along coordinate x perpendicular to the insulator–semiconductor interface is performed for metal–semiconductor contacts with a dielectric gap. It is shown that taking into account the spatial dependence of the density of surface states at rather high semiconductor doping levels leads to a substantial decrease in the barrier height, which promotes the realization of ohmic contacts. It is established that the smaller the metal–semiconductor contact potential difference ϕ_ ms is, the stronger the effect of barrier-height lowering. If ϕ_ ms is negative, this effect can lead to potential sign reversal, i.e., to the realization of an enrichment layer in the space-charge region of the semiconductor even at a high density of surface states. This in turn promotes the manifestation of an anomalous dependence of the contact resistivity on temperature; the resistivity increases with an increase in temperature.
Когерентная обменная корреляция в квантовых системах
Authors: Ганцевич С.В. , Гуревич В.Л.
Published: December 2017

AbstractA number of exchange correlation effects in quantum systems are discussed from a unified point of view. These effects can be observed at both microscopic and macroscopic distances. The analysis of macroscopic correlation effects requires an understanding of the physical mechanism of exchange correlation. This, in turn, requires an analysis of the phase relationships between the wave functions of quantum states that determine the observed physical quantities. The neglect of these phase relationships in the interpretation of correlation experiments gave rise to assumptions such as instantaneous long-range interaction and other similar ideas that contradict the traditional physical principles of short-range interaction, causality, and locality. On the contrary, understanding the physical nature of the correlation mechanism makes it possible to explain these experiments without these kinds of ideas.
Взаимное влияние водорода и вакансий в alpha-цирконии на энергетику их взаимодействия с металлом
Authors: Святкин Л.А. , Коротеев Ю.М. , Чернов И.П.
Published: December 2017

AbstractWe presents a first-principles investigation on the interaction energy of hydrogen and vacancies with α-zirconium. It is established that the presence of vacancies in zirconium increases the hydrogen–metal binding energy; the presence of hydrogen in the zirconium lattice reduces the vacancy formation energy. It is shown that hydrogen and vacancies in zirconium form complexes that considerably distort the metal lattice. The increase in the covalency degree of the metal–metal and hydrogen–metal bounds is observed in the vicinity of these complexes.
Взаимодействие атомов сурьмы с микропорами в кремнии
Authors: Оджаев В.Б. , Петлицкий А.Н. , Плебанович В.И. , Садовский П.К. , Тарасик М.И. , Челядинский А.Р.
Published: December 2017

AbstractThe interaction between Sb atoms and micropores of a getter layer in silicon is studied. The getter layer was obtained via implantation of Sb^+ ions into silicon and subsequent heat treatment processes. The antimony atoms located in the vicinity of micropores are captured by micropores during gettering annealing and lose its electrical activity. The activation energy of capture process to the pores for antimony is lower than that of antimony diffusion in silicon deformation fields around microvoids on the diffusion process.
Дипольное упорядочение и ионная проводимость в NASICON-подобных структурах типа Na-=SUB=-3-=/SUB=-Cr-=SUB=-2-=/SUB=-(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-
Authors: Ногай А.С. , Стефанович С.Ю. , Буш А.А. , Ускенбаев Д.Е. , Ногай А.А.
Published: December 2017

AbstractThe aspects of structure, dipole ordering, and ionic conductivity of the Na_3Cr_2(PO_4)_3 crystal with the four polymorphic phases (α, α', β, and γ) have been investigated. The features of the α-Na_3Cr_2(PO_4)_3 crystal structure and its dipole ordering and relaxation polarization in the low-temperature α and α' phases have been refined. The occurrence of Na_3Cr_2(PO_4)_3 dipole ordering in the α and α' phases and high ionic conductivity in the β and γ phases is attributed to the structural changes in the rhombohedral [ Me _2(PO_4)_3]^–3_3∞ crystal frame upon phase transformations α → α', α' → β, and β → γ. A model for explaining the dipole ordering and ionic conductivity phenomena in Na_3Cr_2(PO_4)_3 is proposed.
Генерация второй оптической гармоники и ее фотоиндуцированная динамика в сегнетоэлектрике-полупроводнике Sn-=SUB=-2-=/SUB=-P-=SUB=-2-=/SUB=-S-=SUB=-6-=/SUB=-
Authors: Брехов К.А. , Гришунин К.А. , Афанасьев Д.В. , Семин С.В. , Шерстюк Н.Э. , Мишина Е.Д. , Кимель А.В.
Published: December 2017

AbstractBy means of optical pump–probe technique, the ultrafast dynamics of nonlinear optical response of the ferroelectric semiconductor Sn_2P_2S_6 crystal excited with a femtosecond laser pulse has been investigated. It has been shown that, under the action of femtosecond pulses, change in optical second harmonic generation occurs in the sample, which can be due to screening of existing electric polarization.
Первопринципные термодинамические характеристики образования кислородных вакансий и примесных центров бора, углерода и азота в анатазе
Authors: Жуков В.П. , Шеин И.Р.
Published: December 2017

AbstractUsing the ab initio projector augmented wave (PAW) method, calculations are performed for the electronic energy-band structure of titanium dioxide having the structure of anatase doped with boron, nitrogen, and carbon. Thermodynamic characteristics are determined for the formation of impurity centers, such as the preference energy for the interstitial position, the energy of impurity oxidation, and the energy of oxygen vacancy formation. It is shown that under the conditions of thermodynamic equilibrium the interstitial position of boron atoms is stable, whereas carbon atoms, depending on the oxygen pressure, can occupy both interstitial positions and substitutional positions of oxygen atoms, and nitrogen atoms replace oxygen atoms. It is shown that the presence of oxygen vacancies promotes the thermodynamic stability of carbon and nitrogen atoms. The obtained densities of electronic states correspond to ESR spectroscopy data, which indicates the presence of spin-polarized electrons in the states of the oxygen vacancy.
Вариативность результирующего поля микродеформаций в кристаллах Zn-=SUB=-1-x-=/SUB=-V-=SUB=-x-=/SUB=-Se (0.01≤ x≤0.10)
Authors: Максимов В.И. , Максимова Е.Н. , Суркова Т.П.
Published: December 2017

AbstractA detailed neutronographic study of the bulk ZnSe crystals doped with vanadium up to the content commensurate with the solubility limit in a semiconductor matrix has been carried out for the first time at room temperature. The data that characterize nonuniformly-deformed states based on the cubic structural modification of the II–VI compounds are obtained. A simplified analysis of the broadening patterns of the diffraction profiles of main Bragg reflexes of the studied crystals shows that the resulting deformation covers macroscopic volumes, and the distribution of vanadium ions in the given cases may significantly deviate from the uniform distribution over volume. Relative to the initial cubic lattice, dominating trends towards symmetry changes preceding the phase stratification in the ZnSe crystals heavily doped with vanadium are revealed.
Влияние магнитного поля на диэлектрическую проницаемость композита 80%La-=SUB=-0.7-=/SUB=-Sr-=SUB=-0.3-=/SUB=-MnO-=SUB=-3-=/SUB=-/20%GeO-=SUB=-2-=/SUB=-
Authors: Кабиров Ю.В. , Гавриляченко В.Г. , Богатин А.С. , Ситало Е.И. , Яценко В.К.
Published: December 2017

AbstractThe dielectric properties of a magnetoresistive conducting two-phase 80%La_0.7Sr_0.3MnO_3/20%GeO_2 (wt %) composite have been studied near the percolation threshold in magnetic fields from 0 to 15 kOe at frequencies of the measurement field from 5 kHz to 1 MHz. The samples have inductive impedances; i.e., their permittivities can be considered negative due to a high conductivity in this frequency range. The permittivity increases in magnitude in magnetic field, and the values of the magnetodielectric coefficient reach 23% at room temperature. The reasons for the effect of magnetic field on the dielectric permittivity of samples are discussed.
Влияние легирования европием на магнитные свойства 3D топологического полуметалла Cd-=SUB=-3-=/SUB=-As-=SUB=-2-=/SUB=- по данным ЭСР
Authors: Горюнов Ю.В. , Натепров А.Н.
Published: December 2017

AbstractInfluence of weak doping by rare-earth elements on magnetic and transport properties of a 3D topological semimetal Cd_3As_2 was studied experimentally. In particular, the doping by europium causes to change of the magnetoresistance sign from positive to negative. First measurements of electron spin resonance and magnetic susceptibility have shown that there are two types of Eu^2+ magnetic ions that occupy the positions of cadmium ions and tetrahedral vacancies and form the ferromagnetic and antiferromagnetic phases, respectively. These facts give an evidence of small-scaled phase separation and a transformation of the Dirac semimetal to a Weyl semimetal induced by magnetic impurities.
Конкуренция доменных стенок и фазы обратной намагниченности в магнитной релаксации спинового переключателя Pt/Co/Ir/Co/Pt
Authors: Моргунов Р.Б. , Львова Г.Л. , Hamadeh A. , Mangin S.
Published: December 2017

AbstractA multilayer Pt/Co/Ir/Co/Pt/GaAs heterostructures demonstrates a long term (to several hours) magnetic relaxation between two stable states of the magnetization of the system. The magnetization reversal of the heterostructure layers occurs both due to the formation of nuclei of the reverse magnetization domains and as a result of their further growth by means of motion of domain walls. The competition between two these processes provides a nonexponential character of the magnetic relaxation. At 300 K, the contributions of these processes to the relaxation are commensurable, while, at temperatures lower than 200 K, the contribution of the nucleation is suppressed and the magnetic relaxation occurs as a result of motion of the domain walls.
Влияние структурных дефектов на магнитные свойства монокристалла EuBaCo-=SUB=-1.90-=/SUB=-O-=SUB=-5.36-=/SUB=-
Authors: Арбузова Т.И. , Наумов С.В. , Телегин С.В.
Published: December 2017

AbstractThe effect of structural defects in cobalt and oxygen sublattices with the constant average oxidation level 3+ of all cobalt ions on the magnetic properties of the EuBaCo_1.90O_5.36 single crystal has been studied. The magnetic properties of the single crystal and the polycrystalline sample of the corresponding composition are compared in the range T = 200–650 K. The results show that the cobalt-deficient EuBaCo_2– x O_5.5–δ samples demonstrate a three-dimensional XY ferromagnetic ordering of magnetic sublattices. The values of the effective magnetic moment at T > 480 K indicate the existence of the IS and HS states of Co^3+ ions. The large difference of values of μ_eff of the EuBaCo_1.90O_5.36 single crystal and polycrystal can be due to that the magnetic ion spins lie in plane ab. The magnetic field directed along plane ab substantially influences the magnetic ordering at T < 300 K.
Доменный эпитаксиальный рост сегнетоэлектрических пленок титаната бария-стронция на сапфире
Authors: Тумаркин А.В. , Одинец А.А.
Published: December 2017

AbstractA model of the epitaxial growth of crystalline multicomponent films on single-crystal substrates with a domain correspondence is presented using a solid solution of barium strontium titanate on sapphire substrates ( r cut). The domain epitaxial growth suggests the matching of the lattice planes of the film and the substrate having similar structures by comparison of domain multiple of an integral number of the interplanar spacings. Variation of the component composition of the solid solution enables changes in the domain size in the range sufficient for epitaxial growth. This method can be used to project the epitaxial growth of films of various solid solutions on single-crystal substrates.
Отклик решетки магнитных наночастиц на импульс магнитного поля вблизи границы устойчивости
Authors: Шутый А.М. , Семенцов Д.И.
Published: December 2017

AbstractThe dynamic response of a system being near the stable equilibrium boundary to an external magnetic field pulse is studied for 2D lattices of magnetic nanoparticles with cubic crystallographic anisotropy. The conditions under which magnetic moment oscillations from individual dipoles propagate to the entire system are revealed. This effect results in the lattice response are significantly larger in the external pulse duration and with an amplitude rather weakly depending on initial conditions and external field parameters, the processes during which the pulse results in reorientation of only individual lattice dipoles.
Эволюция доменной структуры и формирование заряженных доменных стенок при переключении поляризации в монокристаллах ниобата лития, модифицированных отжигом в вакууме
Authors: Пряхина В.И. , Аликин Д.О. , Негашев С.А. , Шур В.Я.
Published: December 2017

AbstractThe evolution of the domain structure during polarization reversal has been investigated in plates of lithium niobate with spatially inhomogeneous electrical conductivity produced by vacuum annealing. The formation of charged domain walls in the crystal bulk has been studied. Revealed features of the domain growth in the bulk have been attributed to the formation of nanodomains under the pyroelectric field and inhomogeneous spatial distribution of the electric field. Creation of the charged domain walls with controlled parameters is of great interest for domain walls engineering.
Акустические аномалии в твердых растворах SrTiO-=SUB=-3-=/SUB=--BiFeO-=SUB=-3-=/SUB=-
Authors: Смирнова Е. , Сотников А. , Зайцева Н. , Schmidt H.
Published: December 2017

AbstractThe results of acoustic investigations of solid solutions SrTiO_3−BiFeO_3 in the temperature range from 100 to 650 K have been presented. The measurements of the velocity and attenuation of the longitudinal ultrasonic mode at a frequency of 10 MHz were carried out by the pulse-echo method. The observed anomalies in velocity and attenuation correlate with the maxima of the dielectric constant in the temperature range of the relaxor state. In addition, the attenuation peaks in the temperature range 400–600 K, which define Burns and T* temperatures, which are characteristic of relaxors, have been identified. The obtained results have allowed the clarifying of the phase diagram of the solid solution system SrTiO_3−BiFeO_3.
Особенности сегнетоэлектрического состояния в двухслойных гетероструктурах на основе титаната бария-стронция
Authors: Стрюков Д.В. , Мухортов В.М. , Головко Ю.И. , Бирюков С.В.
Published: December 2017

AbstractThe structural properties of one- and two-layer heterostructures based on the barium–strontium titanate of various compositions deposited by the Frank–Van der Merve on a magnesium oxide substrate have been studied. The heterostructures have been prepared by the rf sputtering of the stoichiometric ceramic targets in a Plazma 50 SE deposition system. The principal difference of this method of deposition from known analogs is that the growth of single-crystal films occurs from a disperse oxide phase formed in the plasma of a high-current rf discharge during the ceramic target sputtering at the cluster level. The peculiarities of the manifestation of the ferroelectric state in the two-layer heterostructures when changing the sequence order of the films with various compositions of barium–strontium titanate.
Вязкоупругость и механизмы пластичности дентина зубов человека
Authors: Бородин И.Н. , Seyedkavoosi S. , Зайцев Д.В. , Drach B. , Микаелян К.Н. , Панфилов П.Е. , Гуткин М.Ю. , Sevostianov I.
Published: December 2017

AbstractTheoretical models of viscoelastic behavior and plastic deformation mechanisms of human dentin are considered. Using the linear viscoelasticity theory in which creep and relaxation kernels have the form of fraction-exponential functions, numerical values of instantaneous and long-time Young’s moduli and other characteristics of dentin viscoelasticity under uniaxial compression are found. As dentin plastic deformation mechanisms, mutual collagen fiber sliding in the region of contact of their side surfaces, separation of these fibers from each other, and irreversible tension of some collagen fibers, are proposed. It is shown that the second mechanism activation requires a smaller stress than that for activating others. The models of plastic zones at the mode I crack tip, which correspond to these mechanisms, are studied. It is shown that the plastic zone size can increase from a few hundreds of nanometers to hundreds of micrometers with increasing applied stress.
Изменение строения поверхности гетерогенного тела (диорита) при трении
Authors: Веттегрень В.И. , Пономарев А.В. , Соболев Г.А. , Кулик В.Б. , Мамалимов Р.И. , Щербаков И.П. , Башкарев А.Я.
Published: December 2017

AbstractRaman, infrared, and photoluminescent spectroscopy has been used to study changes in the surface structure of quartz diorite caused by friction. Before friction, the diorite surface layer has contained mainly quartz and feldspar crystals. After friction, some quartz and feldspar crystals have been destructed and replaced by a newly formed hydromica mineral with a low friction coefficient such as illite.
Низкотемпературная люминесценция и термостимулированная люминесценция монокристаллов BeO : Mg
Authors: Огородников И.Н. , Петренко М.Д. , Иванов В.Ю.
Published: December 2017

AbstractLuminescence and thermally stimulated luminescence (TL) of BeO: Mg crystals are studied at T = 6–380 K. The TL glow curves and the spectra of luminescence (1.2–6.5 eV), luminescence excitation, and reflection (3.7–20 eV) are obtained. It is found that the introduction of an isovalent magnesium impurity into BeO leads to the appearance of three new broad luminescence bands at 6.2–6.3, 4.3–4.4, and 1.9–2.6 eV. The first two are attributed to the radiative annihilation of a relaxed near-impurity (Mg) exciton, the excited state of which is formed as a result of energy transfer by free excitons. The impurity VUV and UV bands are compared with those for the intrinsic luminescence of BeO caused by the radiative annihilation of self-trapped excitons (STE) of two kinds: the band at 6.2–6.3 eV of BeO: Mg is compared with the band at 6.7 eV (STE_1) of BeO, and the band at 4.3–4.4 eV is compared with the band at 4.9 eV (STE^2) of BeO. In the visible region, the luminescence spectrum is due to a superposition of intracenter transitions in an impurity complex including a magnesium ion. The manifestation of X-ray-induced luminescence bands at T = 6 K in BeO: Mg indicates their excitation during band-to-band transitions and in recombination processes. The energy characteristics of the impurity states in BeO: Mg are determined; the effect of the isovalent impurity on the fluctuation rearrangement of the BeO: Mg structure in the thermal transformation region of STE_1 → STE_2 is revealed.
Люминесценция примесных Ce-=SUP=-3+-=/SUP=- центров в кристаллах KH-=SUB=-2-=/SUB=-PO-=SUB=-4-=/SUB=-:Ce
Authors: Пустоваров В.А. , Огородников И.Н. , Омельков С.И.
Published: December 2017

AbstractThe photoluminescence, X-ray luminescence, and cathodoluminescence spectra of KH_2PO_4 : Ce single crystals contain a nonelementary band of radiation with an energy of 3.55 eV and decay time of 27–33 ns. It is formed by fast radiative interconfiguration d → f transitions between the excited and ground states of Ce^3+ ions, with the ground state is split by a crystalline field. In the range of concentrations studied (0.5–3 × 10^–2 wt %), Ce3+ ions enter the KH_2PO_4 : Ce crystal lattice as substitution ions. Local charge compensation takes place by means of defects in the crystal structure that cause luminescence with a large Stokes shift in the region of 2.4–2.2 eV. The presence of hydrogen sublattice defects decreases the efficiency of energy transport by free charge carriers to the luminescent centers. The interaction of defects and impurity centers manifests itself as a slow inertial building-up of the stationary X-ray luminescence yield of Ce^3+ centers.
Термический отжиг дефектов Стоуна-Уэльса в фуллеренах и нанотрубках
Authors: Подливаев А.И. , Опенов Л.А.
Published: December 2017

AbstractThe thermally activated annealing of topological Stone–Wales defects in carbon fullerenes and nanotubes is studied via molecular dynamics. The temperature dependences of characteristic times are shown to obey the Arrhenius law. The values of the relevant activation energies and frequency factors are found. The results are compared with the simulated potential energy surface data.
Синтез полых углеродных нанооболочек и их применение для суперконденсаторов
Authors: Рудаков Г.А. , Сосунов А.В. , Пономарев Р.С. , Хеннер В.К. , Reza Md. Shamin , Sumanasekera Gamini
Published: December 2017

AbstractThis work is devoted to the study of the synthesis, the description of the structure, and the use of hollow carbon nanoshells 3–5 nm in size. Hollow carbon nanoshells were synthesized by thermolysis of a mixture of nickel acetate and citric acid in the temperature range of 500–700°C. During the chemical reaction, nickel nuclei ~3–5 nm in size are formed, separated from each other by carbon layers. At an annealing temperature of 600°C, the most ordered, close-packed structure is formed, evenly distributed throughout the sample. The etching of nickel with nitric acid resulted in hollow carbon nanoshells with a high specific surface area (~1200 m^2/g) and a homogeneous structure. Raman spectroscopy shows that the graphene-like structure of carbon nanoshells is preserved before and after the etching of nickel, and their defect density does not increase, which enables them to be subjected to new processing (functionalization) in order to obtain additional physical properties. The resulting carbon nanoshells were used as active material of the supercapacitor electrodes. The conducted electrochemical measurements showed that the specific capacitance of the supercapacitor did not fall below 120 F/g at a current density of 0.3 to 3 A after 800 charge/discharge cycles.
Воздействие механических напряжений на зарядовое состояние межфазной границы в гетероструктурах LaAlO-=SUB=-3-=/SUB=-/(001)SrTiO-=SUB=-3-=/SUB=- c нарушенной стехиометрией
Authors: Бойков Ю.А. , Серенков И.Т. , Сахаров В.И. , Данилов В.А.
Published: December 2017

AbstractThe medium-energy ion scattering (MEIS) spectroscopy was used to obtain the data on the structure and stoichiometry of interfaces in LaAlO_3/SrTiO_3 (LAO/STO) heterostructures. The coverage of the LAO/STO heterostructure with a LAO film increased by a factor of almost two as the lanthanum aluminate layer thickness increased from 1 to 6 unit cells. It is shown that the formation of the heterostructure is accompanied by the interchange with Sr ions of the substrate and La ions of the firm. The influence of the oxygen pressure on the formation of the heterostructure has been studied. The conditions required to form nanodimentional interlayer of a quasi-two-dimensional electron gas with high mobility of electrons in the interface region are analyzed.
Магнитная вращающаяся анизотропия в поликристаллических пленках FePt, полученных методом твердофазного синтеза
Authors: Жигалов В.С. , Мягков В.Г. , Быкова Л.Е. , Бондаренко Г.Н. , Великанов Д.А. , Волочаев М.Н.
Published: December 2017

AbstractIt is shown that annealing 550°C of the Fe/Pt bilayer films fabricated by layer-by-layer deposition onto polycrystalline Al_2O_3 substrates in an atomic ratio of Fe: Pt = 71: 29 leads to the formation of the inplane rotational magnetic anisotropy with the easy axis that can be aligned by magnetic field in any direction in the film plane. The increase in the Pt content in the investigated film system to 50 at % leads to an increase in the anisotropy constant to 6.5 × 10^6 erg/cm^3, which exceeds the value in the Fe_71Pt_29 sample by a factor of 6. In addition to the rotational anisotropy, the Fe50Pt50 films are characterized by the perpendicular rotational magnetic anisotropy, which is higher than the film shape anisotropy. Therefore, the easy axis in these samples can be aligned by magnetic field in any spatial direction. According to the X-ray and magnetic measurement data, the synthesized samples have a polycrystalline structure consisting of two ordered phases: magnetically hard L1_0–FePt and magnetically soft L1_2–Fe_3Pt. This gives us grounds to suggest that the rotational magnetic anisotropy originates from the epitaxial intergrowth and exchange coupling of these two phases.