bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesh size control in forming an Ag/AgO nano-network structure for transparent conducting application
Authors: Chen Jia-Wei , Yang Shaobo , Li Chia-Hao , Huang Yang-Yi , Chen Chen-Hua , Yang C C
Published: December 2021

The variation behaviors of the morphology, transmission, and sheet resistance of the surface Ag/AgO nano-network (NNW) structures fabricated under different illumination conditions and with different Ag deposition thicknesses and thermal annealing temperatures in forming initial Ag nanoparticles (NPs) are studied. Generally, an NNW structure with a smaller mesh size or a denser branch distribution has a lower transmission and a lower sheet resistance level. Under the fabrication condition of a broader illumination spectrum, a lower thermal annealing temperature, or a thicker Ag deposition, we can obtain an NNW structure of a smaller mesh size. The mesh size of an NNW structure is basically controlled by the seed density of Brownian tree (BT) at the beginning of light illumination. A BT seed can be formed through a stronger local localized surface plasmon resonance for accelerating Ag oxidation in a certain region. Once an Ag/AgO BT seed is formed, the surrounding Ag NPs are reorganized to form the branches of a BT. Multiple BTs are connected to form a large-area NNW structure, which can serve as a transparent conductor. Under the fabrication conditions of a broader illumination spectrum, 3 nm Ag deposition, and 100 °C thermal annealing, we can implement an NNW structure to achieve ∼1.15 μm in mesh size, ∼90 Ω sq−1 in sheet resistance, and 93%–77% in transmittance within the wavelength range between 370 and 700 nm.
Chiral FexCuySe nanoparticles as peroxidase mimics for colorimetric detection of 3, 4-dihydroxy-phenylalanine enantiomers
Authors: Hu Shuyang , Shuai Qiuyan , Lin Yulong , Fu Yan , Li Meng
Published: December 2021

L-3,4-dihydroxy-phenylalanine (L-dopa) is the most widely used drug in Parkinson’s disease treatment. However, development of cost-effective and high-throughput sensors to accurate enantioselective discrimination of L-dopa and D-dopa remains challenging to date. Herein, on the basis of the peroxidase-mimic activity of chiral FexCuySe nanoparticles, we demonstrated a novel colorimetric sensor for determination of chiral dopa. The surface chiral ligand, L/D-histidine (L/D-His), endowed the nanozymes with enantioselectivity in catalyzing the oxidation of dopa enantiomers. According to the values ofkcat/Km, the efficiency of L-His modified nanoparticles (L-FexCuySe NPs) towards L-dopa was 1.56 times higher than that of D-dopa. While, D-His can facilely reverse the preference of the nanozyme to D-dopa. On the basis of high catalytic activity and enantioselectivity of L-FexCuySe NPs in oxidation of L-dopa, the L-FexCuySe NPs-based system can be utilized for detection of L-dopa. The linear ranges for L-dopa determination were 5μM–0.125 mM and 0.125 mM–1 mM with a detection limit of 1.02μM. Critically, the developed sensor has been successfully applied in the quality control of clinical used L-dopa tablets. Our work sheds light on developing simple and sensitive chiral nanomaterials-based sensors for drug analysis.
Thermoelectric properties of Zn- and Ce-alloyed In2O3 and the effect of SiO2 nanoparticle additives
Authors: Hsin Cheng-Lun , Hsiao Jen-Che , Chen You-Ming , Lee Sheng-Wei
Published: December 2021

Thermoelectric materials are considered promising candidates for thermal energy conversion. This study presents the fabrication of Zn- and Ce-alloyed In2O3 with a porous structure. The electrical conductivity was improved by the alloying effect and an ultra-low thermal conductivity was observed owing to the porous structure, which concomitantly provide a distinct enhancement of ZT. However, SiO2 nanoparticle additives react with the matrix to form a third-phase impurity, which weakens the electrical conductivity and increases the thermal conductivity. A thermoelectric module was constructed for the purpose of thermal heat energy conversion. Our experimental results proved that both an enhancement in electrical conductivity and a suppression in thermal conductivity could be achieved through nano-engineering. This approach presents a feasible route to synthesize porous thermoelectric oxides, and provides insight into the effect of additives; moreover, this approach is a cost-effective method for the fabrication of thermoelectric oxides without traditional hot-pressing and spark-plasma-sintering processes.
Wakefield stimulated terahertz radiation from a plasma grating
Authors: Lehmann Götz , Spatschek Karl Heinz
Published: December 2021

When a short laser pulse propagates in a corrugated plasma, its wakefield interacts with the density and electric field ripples of the plasma. In the present paper, the modulation of the plasma originates from two counter-propagating long laser pulses, i.e. the corrugated plasma can be as- sumed as a so called plasma grating. PIC (particle in cell) simulations show electromagnetic wave radiation at a frequency just above the plasma frequency when the wakefield interacts with the grating. An electromagnetic instability is proposed as the reason for the emission process. The electrostatic driver of the electromagnetic instability is the beat of wake and grating. That beat mode possess large wavenumber (originating from the small grating wavelength) and small fre- quency (of the order of the plasma frequency) when one concentrates on small ratios of the plasma modulation length to the wavelength of the wakefield. The latter situation occurs when the long laser pulses (which generate the grating) as well as the short laser pulse (which drives the wakefield) have similar frequency ω0 ≫ ωpe where ωpe is the plasma frequency. The coherent volume emission process lasts for a while. It is finally superseded by terahertz transition radiation at the boundaries of the original grating.
Application of encapsulated hollow gold nanocluster targets for high-quality and quasi-monoenergetic ions generation
Authors: Mehrangiz Mahsa
Published: December 2021

With persistent progress in ultra-intense laser pulses, Coulomb explosions (CE) of spherical nanoclusters can in principle produce high-quality quasi-monoenergetic ions. Focusing on using CE framework, in this paper, I have proposed a target scheme to accelerate the light/heavy ion beams. The scheme relies on encapsulating a hollow gold nanocluster inside a hollow proton-carbon (HC) nanosphere. The ability of this suggestion has been simulated by the two-dimensional particle-in-cell code (EPOCH). Simulation results exhibit that a hollow gold cluster can positively increase the electron extraction. This condition may improve the acceleration of low-divergence H+, C6+, and Au67+ ions. The simulation shows that at the end of the interaction, for a gold cluster with an optimal hollow radius of 91.3 nm, the cut-off energy of H+, C6+, and Au67+ are about 54.9, 51.5, and 54.9 MeV u−1, respectively. In this case, an increase of about 52% for H+ and 61% for C6+ is obtained, contrast to bare HC hollow nanosphere (i.e. a hollow nanosphere with no cluster), while the relative divergence decreases to 1.38 and 1.86, respectively, for H+ and C6+ ions. I have also compared my simulation results with another proposed target structure composed of a void area with an optimum diameter of 70.4 nm between the fully-gold nanocluster and HC nanosphere. I have exhibited that the results are improved, contrast to bare nanosphere. However, the cut-off energy suppression and angular divergence increase are shown compared with encapsulated hollow gold nanocluster structure.
Sensitivity analysis for detecting chemicals by the optical chemical sensor based Photonic Crystal Fiber (PCF) in the Terahertz (THz) regime
Authors: Hossain Md Selim , Faruq Md Omar , Rana Md Masud , Sen Shuvo , Haque Md Dulal , Azad Mir Mohammad
Published: December 2021

This research article demonstrates a good simulation result for identifying and detecting various industrial chemicals in a Terahertz (THz) waveguide with a new heptagonal, five layers of heptagonal photonic fiber elliptic form, heptagonal cladding shape (H-PCF). COMSOL 4.2 software based on finite element (FEM) methods and perfectly matched layers check our composition (PML). The different chemicals are also differentiated and identified by each other in different parameters H-PCF fibers show a high relative sensitivity of ethanol of approximately 86.50 percent after numerical analysis, Benzene around 89.35%, and water around 85.15% at a frequency of around 0.7 THz. In our experiment, we obtained very low confinement losses at 1 terahertz (THz) such as 5.95 × 10−08 dB/m for Ethanol 6.67 × 10−08 dB/m for Benzene, and 5.80 × 10−08 dB/m for water. Regarding these results, we can strongly recommend that our proposed heptagonal photonic crystal fiber (H-PCF) will be more congenial in biomedical, bio-medicine, and industrial areas for the identification and detection of various types of chemicals with the help of a THz waveguide.
Performance enhancement of armchair graphene nanoribbon resonant tunneling diode using V-shaped potential well
Authors: Mishra Madhusudan , Das Nikhil R. , Sahoo Narayan , Sahu Trinath
Published: December 2021

We study the electron transport in armchair graphene nanoribbon (AGNR) resonant tunneling diode (RTD) using square and V-shaped potential well profiles. We use non-equilibrium Green’s function formalism to analyze the transmission and I–V characteristics. Results show that an enhancement in the peak current (I

p
) can be obtained by reducing the well width (W

w
) or barrier width (W

b
). As W

w
decreases, I

p
shifts to a higher peak voltage (V

p
), while there is almost no change in V

p
with decreasing W

b
. It is gratifying to note that there is an enhancement in I

p
by about 1.6 times for a V-shaped well over a square well. Furthermore, in the case of a V-shaped well, the negative differential resistance occurs in a shorter voltage range, which may beneficial for ultra-fast switching and high-frequency signal generation. Our work anticipates the suitability of graphene having better design flexibility, to develop ideally 2D RTDs for use in ultra-dense nano-electronic circuits and systems.
On primordial black holes and secondary gravitational waves generated from inflation with solo/multi-bumpy potential *
Authors: Zheng Ruifeng , Shi Jiaming , Qiu Taotao
Published: December 2021

It is well known that a primordial black hole (PBH) can be generated in the inflation process of the early universe, especially when the inflation field has a number of non-trivial features that could break the slow-roll condition. In this study, we investigate a toy model of inflation with bumpy potential, which has one or several bumps. We determined that the potential with multi-bump can generate power spectra with multi-peaks in small-scale region, which can in turn predict the generation of primordial black holes in various mass ranges. We also consider the two possibilities of PBH formation by spherical and elliptical collapses. Finally, we discuss the scalar-induced gravitational waves (SIGWs) generated by linear scalar perturbations at second-order.
The Precision Analysis of the Chinese VLBI Network in Probe Delay Measurement
Authors: Li Ting , Liu Lei , Zheng Wei-Min , Zhang Juan
Published: December 2021

We propose a Very Long Baseline Interferometry (VLBI) precision evaluation method for probe delay measurement, so as to investigate the error contributions from different components in the Chinese VLBI Network (CVN). This method takes the idea of traditional closure delay analysis for distant radio sources. It focuses on the VLBI closure delay only and therefore excludes the influence of probe orbit determination, which makes it very suitable to evaluate the capability of VLBI probe delay measurement. In this paper, we first introduce the principles of closure delay analysis. Then the statistical results of typical CE5 (Chinese Chang’e 5 lunar exploration mission) and HX1 (Chinese Mars exploration mission) observations are presented, including the comparison of the closure delay precisions between CE5 and HX1 for four closed baseline triangles in CVN. According to the result, we realize that the precision discrepancy between CE5 and HX1 in the closure delay analysis is less than that of residual delay after orbit determination, which reflects the precision level of the VLBI delay measurement.
Electrical transport properties of cerium doped Bi2Te3 thin films grown by molecular beam epitaxy
Authors: Teng Peng , Zhou Tong , Wang Yonghuan , Zhao Ke , Zhu Xiegang , Lai Xinchun
Published: December 2021

Introducing magnetism into topological insulators (TIs) can tune the topological surface states and produce exotic physical effects. Rare earth elements are considered as important dopant candidates, due to their large magnetic moments from heavily shielded 4f electrons. As the first element with just one 4f electron, cerium (Ce) offers an ideal platform for exploring the doping effect of f-electron in TIs. Here in this work, we have grown cerium-doped topological insulator Bi2Te3 thin films on an Al2O3(0001) substrate by molecular beam epitaxy (MBE). Electronic transport measurements revealed the Kondo effect, weak anti-localization (WAL) effect and suppression of surface conducting channels by Ce doping. Our research shows the fundamental doping effects of Ce in Bi2Te3 thin films, and demonstrates that such a system could be a good platform for further research.
Development of high-power, long-pulse, multi-frequency ECH/CD system for JT-60SA
Authors: Kobayashi T. , Yamazaki H. , Hiranai S. , Sawahata M. , Terakado M. , Ishita K. , Hinata J. , Sato F. , Wada K. , Toida N. , Ikeda R. , Shinya T. , Yajima S. , Kajiwara K. , Takahashi K. , Moriayama S.
Published: December 2021

A gyrotron and a matching optics unit (MOU) for the multi-frequency electron cyclotron heating and current drive (ECH/CD) system in JT-60SA have been developed successfully. The gyrotron demonstrated stable operation at high powers of 1.5 MW for 5 s and 1.9 MW for 1 s at 110 GHz. To obtain high HE11 mode purity (>90%) at the outlet of the waveguide in the ECH/CD launcher, a MOU for operating at three frequencies of 82 GHz, 110 GHz, and 138 GHz that includes three pairs of water-cooled phase correcting mirrors has been developed, which allows the mirrors to be changed without opening the evacuated MOU. The mode purity at the inlet of a dummy load in the transmission line was evaluated at high-power and an HE11 mode purity of >90% was obtained at three frequencies.
Geant4 simulation of the Tunka-Grande experiment
Authors: Monkhoev R , Ternovoy M , Astapov I , Bezyazeekov P , Borodin A , Brueckner M , Budnev N , Chiavassa A , Dyachok A , Gafarov A , Garmash A , Grebenyuk V , Gress O , Gress T , Grinyuk A , Grishin O , Horns D , Igoshin A , Ivanova A , Ivanova Al , Kalmykov N , Kindin V , Kiryuhin S , Kokoulin R , Kompaniets K , Korosteleva E , Kozhin V , Kravchenko E , Kryukov A , Kuzmichev L , Lagutin A , Lemeshev Y , Lubsandorzhiev B , Lubsandorzhiev N , Lukyantsev D , Malakhov S , Mirgazov R , Mirzoyan R , Osipova E , Pakhorukov A , Pankov L , Petrukhin A , Poddubnyi I , Poleschuk V , Ponomareva V , Popesku M , Popova E , Porelli A , Postnikov E , Prosin V , Ptuskin V , Pushnin A , Raikin R , Rubtsov G , Ryabov E , Sagan Y , Samoliga V , Sabirov B , Silaev A , Sidorenkov A , Sinegovsky S , Skurikhin A , Slunecka V , Sokolov A , Suvorkin Y , Sveshnikova L , Tabolenko V , Tarashchansky B , Tkachev L , Tluczykont M , Tanaev A , Togoo R , Ushakov N , Vaidyanathan A , Volchugov P , Voronin D , Wischnewski R , Zagorodnikov A , Zhaglova A , Zhurov D , Yashin I
Published: December 2021

The Tunka-Grande array is part of a single experimental complex, which also includes the Tunka-133 and TAIGA-HiScORE (High Sensitivity COsmic Rays and gamma Explorer) wide-angle Cherenkov arrays, TAIGA-IACT array (Imaging Atmospheric Cherenkov Telescope) and TAGA-MUON scintillation array. This complex is located in the Tunka Valley (Buryatia Republic, Russia), 50 km from Lake Baikal. It is designed to study the energy spectrum and the mass composition of charged cosmic rays in the energy range 100 TeV - 1000 PeV, to search for diffuse gamma rays above 100 TeV and to study local sources of gamma rays with energies above 30 TeV.

This report outlines 3 key points. The first is the description of the Tunka-Grande scintillation array. The second one presents the computer simulation strategy of the Tunka Grande array based on the Geant4 software. The third one is devoted to the prospects for future research in the field of cosmic ray physics and gamma-ray astronomy using simulation results.
Detailed study of the GRB 190114C spectral lags in the energy range of 5 keV – 2 MeV
Authors: Dranevich V A , Dmitriev P B
Published: December 2021

The spectral lags of gamma ray bursts are defined as the difference in the registration time of the same radiation pulse in different energy channels of the recording device. This parameter can characterize both the mechanism of radiation generation by the source and the physical conditions of radiation propagation from the source to the observer. In this paper, the dependence of the arrival time of photons on their energy for the gamma ray burst GRB 190114C is obtained from the data of the Gamma ray Burst Monitor (NaI detectors) of the Fermi Gamma ray Space Telescope. It is shown that this dependence is mainly due to the back edges of the light curve pulses. The spectral lags of the leading edges of the pulses are small and comparable in magnitude to the measurement errors. The observed anomaly in the energy range from 5 to 20 keV is probably related to the quasi-thermal radiation of the source.
Modeling of cosmic ray 22Ne-enrichment in compact star clusters
Authors: Kalyashova M E , Bykov A M
Published: December 2021

22Ne/20Ne isotopic ratio is found to be about 5 times higher in Galactic cosmic rays (GCRs) than in the solar wind. In this paper we develop the hypothesis that the 22Ne overabundance in CRs is generated in compact massive star clusters which contain populations of Wolf-Rayet stars. Winds of Wolf-Rayet stars are considered to have high content of 22Ne. We assume that particle acceleration occurs on the ensemble of strong shocks from the massive stars’ winds. We present a model of cosmic ray enrichment with 22Ne, adding isotopic yields from supernovae and taking into account the acceleration efficiency during the lifetime of the stars. The impact of the parameters (the initial mass function in the cluster, rotation velocity, black hole cut-off mass) is discussed. The energy balance for our model is calculated.
Influence of the temperature of the photosphere and deeper layers of the Sun on the spectra of gamma quanta with energies above 511 keV during solar flares
Authors: Vasilyev G I
Published: December 2021

Gamma-ray quanta, which occur during solar flares due to the interaction of accelerated protons with the photosphere and deeper layers of the sun, enter interplanetary space from a thickness of several tens of g/cm2. In the presented work, gamma quanta with energies of more than 511 keV are considered. This makes it possible to exclude from consideration the dependence of the probability of ortho- and parapositronium formation on the temperature and density of the solar matter. And also do not consider the probability of annihilation by two or 3 gamma quanta. Thus, the reactions of thermal neutrons remain dependent on the temperature. As the ambient temperature increases, the average number of elastic neutron scattering before capture increases. This leads to a more likely penetration of neutrons to a greater depth or their departure into the interplanetary space. The high temperature of the Sun below the photosphere may be one of the reasons for the absence of the 2.223 MeV line in solar flares with registered protons in the PAMELA and AMS2 experiments. Using the GEANT4 package, the spectra of gamma-quanta arising in nuclear interactions are calculated. The temperature-dependent features of the gamma-ray spectra are discussed.
The analysis of Titan’s physical surface using multifractal geometry methods
Authors: Morena Carlos De La , Nefedyev Y A , Andreev A O , Ahmedshina E N , Arkhipova A A , Kronrod E V , Demina N Y
Published: December 2021

Titan makes up 95% of the mass of all 82 satellites of Saturn. Titan’s diameter is 5152 km, which means that it is larger than the Moon by 50%, and it is also significantly larger than Mercury. On the satellite, a subsurface ocean is possible, the theory of the presence of which has already been advanced earlier by some scientists. It is located under a layer of ice and consists of 10% ammonia, which is a natural antifreeze for it and does not allow the ocean to freeze. On the one hand, the ocean contains a huge amount of salt, which makes the likelihood of life in it hardly possible. But on the other hand, since chemical processes constantly occur on Titan, forming molecules of complex hydrocarbon substances, this can lead to the emergence of the simplest forms of life. There are limitations on the probabilistic and statistical approaches, since not every process and not every result (form and structure of the system) is probabilistic in nature. In contrast to this, fractal analysis allows one to study the structure of complex objects, taking into account their qualitative specifics, for example, the relationship between the structure and the processes of its formation. When constructing a harmonic model of Titan, the method of decomposition of topographic information into spherical functions was used. As a result, based on the harmonic analysis of the Cassini mission data, a topographic model of Titan was created. In the final form, the model describing Titan’s surface includes the expansion of the height parameter depending on the spherical coordinates into a slowly converging regression series of spherical harmonics. For modeling surface details of the surface on a scale of 1 degree requires analysis of the (180 + 1)2 harmonic expansion coefficients. An over determined topographic information system was solved to meet the regression modelling conditions. In this case, a number of qualitative stochastic data, such as external measures, were used together with the standard postulation of the harmonic system of the Titan model. As a result of a sampling of self-similar regions (with close values of the self-similarity coefficients) on the surface of Titan, coinciding with the SRGB parameter (characterizes the color fractal dimension), the elements of the satellite’s surface were determined, which with a high degree of probability were evolutionarily formed under the action of the same selenochemical processes.
Slow motion pulsar wind nebulae
Authors: Levenfish K P , Ponomaryov G A , Petrov A E , Bykov A M , Krassilchtchikov A M
Published: December 2021

We show that even the slow (subsonic) motion of pulsar wind nebulae (PWNe) relative to an ambient matter has a significant impact on their observables. The motion changes the appearance of nebulae on X-ray images, comparing to what would be observed for a nebula at rest. Accounting for the relative motion is necessary to avoid misinterpretation of the structure of the nebulae when analyzing their X-ray morphology. The motion also introduces some extra time scales in variability of non-thermal high-energy emission of PWNe and allows to reproduce a number of their structures that are not explained by stationary nebula models.
Studying the fractal properties of Ceres
Authors: Mubarakshina R R , Andreev A O , Nefedyev Y A , Arkhipova A A , Kronrod E V , Demina N Y
Published: December 2021

Currently, the asteroid Ceres belongs to small celestial bodies with the most well-known physical parameters. The study of the structural and real properties of Ceres is an urgent and modern task, the solution of which will make it possible to develop the evolutionary theory of a minor planet. In this work, the fractal properties of the dwarf planet Ceres were analyzed using data from the Dawn space mission. Using the expansion in a harmonic series in spherical functions the height parameters of the structural model of Ceres, a 3D model of Ceres was constructed. The analysis showed that the resulting system has a complex multiparameter fractal configuration. The study of such objects requires the use of harmonic multiparameter methods. Multivariate fractal analysis allows to represent systems similar to the Ceres model in the form of a spectrum of fractal dimensions. The advantage of fractal analysis is the ability to explore local areas of the physical surface. In this work, the Minkowski algorithm was used for this purpose. At the final stage, an overdetermined system was solved for various local areas of topocentric information in order to postulate a model that takes into account external measures. Fractal dimensions D are determined for local regions and the entire model of the planet. Fractal dimensions vary from 1.37 to 1.92 depending on the longitude and latitude of Ceres. The main results are as follows: 1) the structure of the Ceres surface varies more strongly in longitude; 2) the structure of Ceres is smoother in latitude; 3) the coefficient of self-similarity changes rather quickly in longitude, which indicates that different local regions of the minor planet were formed under the influence of various physical processes. It is necessary to emphasize that the resulting fractal dimensions are significantly scattered both in longitude and latitude of Ceres. This fact confirms the presence of a complex structure in the spatial model of a minor planet. This also applies to the actual physical surface of Ceres. The results of the work allow us to conclude that fractal modeling can give independent values of the fractal dimension both for the entire model of Ceres and for its local macrostructural regions.
Long-term evolution of coronal holes on the Sun and occurrence frequencies of magnetic storms with gradual commencements
Authors: Veretenenko S , Ogurtsov M , Obridko V , Tlatov A
Published: December 2021

Long-term evolution of areas with open configuration of magnetic field (coronal holes) on the Sun reconstructed on the basis of H-alpha synoptic charts for the period 1887-2016 was studied and compared with annual occurrence frequencies of magnetic storms with gradual (GC) commencements. It was found that correlation between yearly values of coronal hole (CH) areas and sunspot numbers with no time shift is negative and not strong, but increases up to ∼0.6-0.7 when CH areas are delayed by 4-5 years relative to sunspot numbers. Temporal variations of CH areas in the Northern and Southern hemispheres are characterized by dominant ∼11-year periodicities; however, they differ significantly on the multidecadal time scale. The wavelet spectra of CH areas in the Southern hemisphere, unlike those in the Northern one, reveal persistent periodicities of ∼30-35 years on the studied time interval. Similar periodicities of ∼30-35 years are observed in annual occurrences of GC magnetic storms which are caused by high-speed streams of solar wind from coronal holes. The results of cross wavelet analysis of annual occurrence frequencies of GC magnetic storms and areas of coronal holes revealed common periodicities ∼11, ∼35 and ∼60 years which confirmed a close link of these storms with the evolution of large-scale magnetic fields on the Sun.
The use of the formalism of the complex electrical module in the monitoring of oncological diseases
Authors: Salnikova Zh A , Castro R A
Published: December 2021

The article discusses the use of the formalism of a complex electrical module to determine the relaxation parameters α, β, τ of blood serum. Approximating formulas for the real and imaginary components of the electrical modulus, obtained from the Havrilyak-Negami equation, are given. The assumption is made that for healthy organisms the parameters α, β, τ are constant (or change insignificantly), and for cancer patients they change, and the more the disease develops, the more these parameters change. It is also assumed that the activation energies Ea
of macromolecules in the composition of blood serum are different for healthy and diseased organisms. Thus, the study of the dynamics of changes in the parameters α, β, τ, Ea
can be used in the monitoring of oncological diseases.
Analysis of infrared spectra of blood serum of patients with multiple myeloma
Authors: Chernyshev D A , Mikhailets E S , Telnaya E A , Plotnikova L V , Garifullin A D , Kuvshinov A Y , Voloshin S V , Polyanichko A M
Published: December 2021

Multiple myeloma (MM) is a serious disease that is difficult to diagnose especially at early stage. Infrared spectroscopy is a promising approach for diagnosing MM. The principal component analysis (PCA) allows us to reduce the dimension of the data and keep only the important variables. In this study, we apply principal components analysis to infrared (IR) spectra of blood serum from healthy donors and multiple myeloma patients. As a result of the analysis by PCA, it was possible to visualize the separation of patient’s and donor’s samples into two clusters. The result indicates that this method is potentially applicable for diagnosis of multiple myeloma.
Generation in the regime with three resonance frequencies
Authors: Oparina Yu S , Savilov A V
Published: December 2021

If the group velocity of the wave is close to the bunch velocity, the bunch placed in the maximumum of the radiated pulse. It provides high effeciency of the electron-wave interaction. However, there are other factors related to particle dynamics, which have strong influence on the radiation process. In this paper the regime with three resonance frequencies is discussed. By varying the phase size of the electron bunch, the generation conditions at each of the frequencies can be changed. There are results for the spontaneous coherent super-radiative undulator emission in the terahertz frequency range from a short (as compared to the wavelength of the radiated wave) dense electron bunch. As a result, an electron bunch radiates two pulses with amplitudes of the radiated fields ∼ 10-70 MV/m.
Non-equilibrium methods for synthesis and modification of gallium oxide
Authors: Nikolskaya A A , Korolev D S , Mikhaylov A N , Mullagaliev T D , Chigirinsky Yu I , Belov A I , Nezhdanov A V , Trushin V N , Nikolichev D E , Almaev A V , Giulian R , Kumar M , Tetelbaum D I
Published: December 2021

Synthesis and modification of gallium oxide as a wide-bandgap semiconductor is a topical task in the fields of power electronics, UV detectors, gas sensors, telecommunication. In the present work, the Ga2O3 films deposited on sapphire substrates by magnetron sputtering have been studied. The influence of deposition parameters and subsequent annealing on the structure and optical properties of the synthesized films is analyzed. Ion doping of magnetron-deposited films with silicon is carried out by the ion implantation method. It is shown by the Raman scattering and optical transmission spectroscopy that ion irradiation leads to the disordering of the crystal structure, but subsequent annealing results in a partial recovery of the structure. Hall-effect measurements for irradiated and then annealed films do not reveal the formation of a conducting layer. Apparently, this is due to the fact that the main contribution to the resistance is made by grain boundaries in the magnetron-deposited films.
In-situ estimation of defect volume from parameters of acoustic emission signals
Authors: Damaskinskaya E E , Hilarov V L , Panteleev I A , Korost D V , Damaskinskii K A
Published: December 2021

By using two methods of nondestructive testing, i.e., acoustic emission (AE) measurements and X-ray computed microtomography (CT), an experimental study of defect accumulation during a uniaxial compression of a natural heterogeneous material was carried out. A joint analysis of the AE and CT data revealed a correspondence between energy characteristics of the acoustic emission accompanying defect formation and volume of defects. It is shown that the dependence of the total energy of AE signals on the defect volume is linear, which is consistent with the phenomenological dependences for earthquake focuses obtained earlier. The linear dependence was used to estimate the average defect size. It is shown that, regardless of the assumed defect shape, its average linear size does not exceed 100 μm.
Prediction of radiation degradation of Si detectors irradiated by relativistic ions of different masses
Authors: Mitina D , Verbitskaya E , Eremin I , Fadeeva N
Published: December 2021

The presented paper is focused around radiation damage of silicon material under the different ions irradiation. The ion total energy range is 0.7 GeV for 7Li to 208 GeV for 208Pb. The results of TRIM modeling for the set of six ions are presented. The extracted information about vacancy production allows making first assumptions of the Si degradation dependence on mass and energy of the incident ion.
Raman scattering and luminescence in single crystals of the amino acid glycine C2H5NO2 with an admixture of croconic acid C5H2O5
Authors: Balashova E V , Smirnov A N , Davydov Yu V , Krichevtsov B B , Starukhin A N
Published: December 2021

Single crystals of the amino acid glycine (Gly) C2H5NO2 doped with croconic acid (CA) C5H2O5 were synthesized by evaporation from an aqueous solution. The crystals grow in the form of hexagonal pyramids or thin plates. Analysis of polarized Raman scattering spectra (excitation wavelength of 532 nm) measured at room temperatures showed that crystals in the form of pyramids corresponded to γ-polymorph (γ-Gly), and crystals in the form of plates to α-polymorph of glycine (α - Gly). The presence of croconic acid molecules in the crystals is confirmed by the change in their color from white in pure Gly crystals to light or dark yellow, characteristic of CA crystals, as well as the presence of weak lines corresponding to CA in the Raman spectra. In single crystals of both Gly:CA polymorphs, strong green luminescence significantly exceeding the intensity of Raman scattering is observed in the range 400 - 700 nm with a maximum at 510 nm (2.44 eV) upon excitation at λ= 325 nm.
Study of the effect of nitrogen and hydrogen on the structure and magnetic properties of (Sm, Er)2Fe17 alloys
Authors: Tereshina I S , Veselova S V , Akimova O V , Paukov M A , Karpenkov A Yu , Argunov E V , Verbetsky V N
Published: December 2021

Materials based on the Sm2Fe17 compound with nitrogen have great potential for the manufacture of highly efficient permanent magnets. The initial, nitrided, and hydrogenated alloys based on the Sm2Fe17 intermetallic compound with partial substitution of erbium atoms for samarium atoms Sm1.2Er0.8Fe17(H, N)x have been studied by X-ray phase analysis and scanning electron microscopy. Nanopowders of Sm1.2Er0.8Fe17N2 were obtained by mechanical grinding. The grinding time was varied from 0 to 60 minutes. The magnetic hysteresis properties of all powder samples were studied in static magnetic fields up to 7 T, as well as in pulsed magnetic fields up to 60 T. The strength of the intersublattice exchange interaction was estimated. The obtained values λ are valid only for the explored concentration of Sm/Er ions.
Photo-e.m.f. at a metal/layered n-InSe semiconductor contact under heating conditions of current carriers by an electric field
Authors: Abdinov A S , Babayeva R F
Published: December 2021

The features of the photo-e.m.f. are experimentally studied on the metal/n-InSe contact under conditions of heating the current carriers by an electric field in the temperature range of T0
=77÷350 K. The dependences of the photo-e.m.f. (Uph
) value have been measured in the absence of

(

U

p
h

0

)

and under the condition of heating the current carriers

(

U

p
h

E
^

)

, as well as the value of

Δ

U

p
h

=
(

U

p
h

E
^

-U

p
h

0

)

from the wavelength (λ) and light intensity (I), heating electric field strength (Ê), time (τ), temperature (T0
), the initial value of the dark resistivity (ρD0 at 77K) n-InSe. It has been established that the heating of current carriers by an electric field significantly affects the magnitude and behavior of the photo-e.m.f. characteristics on the metal/n-InSe contact. The nature of this effect depends on T0,ρD0, I. The value of

U

p
h

E
^

significantly exceeds the value of

U

p
h

0

. With an increase in Ê, the value of AUph increases linearly (ΔUph~Ê) at relatively small Ê, and the dependence of ΔUph
(Ê) reaches saturation at higher Ê. The value of ΔUph
decreases with increasing
ρD0
, at relatively small Ê. With an increase in
ρD0
, the relaxation time of the photo-e.m.f. also increases when turned off the pulse of the electric field. The obtained experimental results are explained on the basis of the dependence of the photo-e.m.f. on the metal/n-InSe contact on the effective temperature of heated current carriers (Te
), considering the effect of the spatial inhomogeneity of n-InSe crystals on the photo-e.m.f. and on the process of heating the current carriers.
Regular electrically charged objects in Nonlinear Electrodynamics coupled to Gravity
Authors: Dymnikova Irina , Galaktionov Evgeny
Published: December 2021

We present a brief review of the basic properties of regular electrically charged black holes and electromagnetic solitons, predicted by analysis of regular solutions to dynamical equations of Nonlinear Electrodynamics minimally coupled to Gravity (NED-GR). The fundamental generic feature of regular NED-GR objects is the de Sitter vacuum interiors and the relation of their masses to spacetime symmetry breaking from the de Sitter group. Regular spinning NED-GR objects have interior de Sitter vacuum disk with the properties of a perfect conductor and ideal diamagnetic. The disk is confined by the ring with the superconducting current which provides the non-dissipative source of the electromagnetic fields and of the intrinsic magnetic momentum.
Peculiarities of the memory state formation in thin Ge2Sb2Te5 films
Authors: Fefelov S A , Kazakova L P , Bogoslovskiy N A , Yakubov A O , Bylev A B
Published: December 2021

The current-voltage characteristics of Ge2Sb2Te5 thin films were measured by a sequence of triangular current pulses with an increasing maximum current. Each current pulse forms in the sample a conducting filament with an area proportional to the maximum current in the recording pulse.
Critical behavior of a two-dimensional ferromagnetic film on a non-magnetic substrate
Authors: Belim S V , Bychkov I V , Maltsev I V
Published: December 2021

In this paper, we investigate the behavior of a ferromagnetic (FM) film on a nonmagnetic substrate near the Curie point by the computer simulation. The influence of the substrate is specified using the two-dimensional Frenkel-Kontorova (FK) potential. The study is carried out for a two-dimensional film described by the Ising model. At the first step, we calculate the positions of the substrate’s atoms in the ground state depending on the parameters. The parameters are (i) the ratio of the substrate periods and the crystal lattice of the film; and (ii) the ratio of the substrate potential amplitude to the elasticity coefficient of interatomic interaction. The period ratio determines the system coverage ratio. Minimization of the system’s total energy determines the ground state. Calculations show that the ground state has a periodic structure that differs from a square lattice with a coverage coefficient not equal to unity. We calculate the displacements of atoms from the equilibrium position for systems with a different linear scale.
Method for critical current angular dependencies analysis of superconducting tapes
Authors: Guryev V V , Shavkin S V , Kruglov V S
Published: December 2021

Various applications of superconducting materials require accounting of the critical current anisotropy relative to magnetic field direction - I
c7(θ). However, today there is no sufficiently comprehensive model that takes into account the anisotropy, therefore the angular dependences are usually not analysed, but only described using various mathematical formulas. As a result, the fitting parameters have no physical meaning and it is difficult to correlate the picture with the features of the microstructure. In this paper, we propose a method for analysing the critical current angular dependences based on the anisotropic pinning model. The applicability of this model for conventional superconducting Nb-Ti tapes with one peak in the I
c7(θ) dependence is shown. The possibility of extending this model to analyse the angular dependences of HTS materials is discussed.
Effect of wet KOH etching on structural properties of GaN nanowires grown on patterned SiOx/Si substrates
Authors: Lendyashova V V , Kotlyar K P , Gridchin V O , Reznik R R , Lihachev A I , Soshnikov I P , Cirlin G E
Published: December 2021

The possibility of the controlled removal of GaN nanowires (NWs) from an SiOx inhibitor layer of patterned SiOx/Si substrates has been demonstrated. It has been found that the wet KOH etching preserves the selectively grown GaN NWs on Si surface, whereas the GaN NWs grown on inhibitor SiOx layer are removing. The effect is described by the difference in polarity between GaN NWs grown on a Si surface and NWs grown on a SiOx inhibitor layer.
Effect of SFE on the evolution of crystallographic texture in Cu-Zn alloys subjected to severe plastic deformation
Authors: Zaynullina L I , Sitdikov V D , Sitdikova G F , Alexandrov I V
Published: December 2021

Within the framework of experimental investigations and computer modeling using the viscoplastic self-consistent (VPSC) model of a material plastic flow, the regularities of preferential orientations formation were established, the proportion of certain texture components was estimated, and existing slip systems (SS) and twinning systems (TS) were identified for equal-channel angular pressing (ECAP) of copper alloys depending on the stacking fault energy (SFE).
Spectroscopic evidence of tunnel coupling between CdTe quantum wells in the CdTe/ZnTe heterostructures
Authors: Agekyan V , Filosofov N , Karczewski G , Serov A , Shtrom I , Reznitsky A
Published: December 2021

The photoluminescence (PL) spectra of CdTe/ZnTe double quantum wells (QWs) are studied on a series of samples containing two CdTe layers with nominal thicknesses of 2 and 4 monolayers (ML) in the ZnTe matrix. The QWs were grown in atomic-layer epitaxy and separated by ZnTe spacers with the thicknesses dsp
=40−160 ML. The dependences of the relative intensity of shallow QW1 and deep QW2 PL bands (I1
and I2
, respectively) on the pump intensity (J) when excited by the lasers with different radiation wavelengths are investigated. It is found that in the sample with dsp=40 ML, the ratio Y(J)=I1/I2 depends on J and the shape of the Y(J) dependency changes with the excitation wavelength. In the samples with dsp
> 70 ML Y(J) also changes with the excitation intensity J, but the shape of this dependence is the same for various excitation wavelengths. It is concluded that the energy relaxation in these samples is influenced not only by the tunneling of charge carriers from QW1 to QW2, but also by carrier relaxation at the nonradiative centers, for which the recombination rate is different for shallow and deep QWs.
Study of the optical properties of a NiO/AuNP/NiO nanocomposite film transferred onto a transparent flexible substrate
Authors: Enns Y , Kondrateva A , Komarevtsev I , Kazakin A , Vyacheslavova E , Kuznetsov A , Andreeva V D , Mishin M
Published: December 2021

In this work a technique for optically active nanocomposite structures consisting of an oxide matrix with plasmonic NPs were demonstrated. A nanocomposite film was formed on a silicon substrate by NiO oxide matrix sputtering and gold nanoparticles dewetting. Studies of the morphology, elemental composition, and structure of the nanocomposite using SEM, EDS, XRD methods are presented. The transfer of the film onto a polymer substrate made it possible to study the optical characteristics of the obtained structures. It is shown that formed nanocomposite coatings on a polymer substrate are highly flexible and exhibit excellent mechanical properties.
Wafer fusion technique features for near-IR laser sources
Authors: Rochas S S , Novikov I I , Karachinsky L Ya , Babichev A V , Blokhin S A , Nevedomskii V N , Voropaev K O , Egorov A Yu
Published: December 2021

The paper presents the results of studies of the conditions for the formation of A3B5 compound semiconductors heterointerfaces including InP, InGaAsP and GaAs layers. The heterostructures were grown by molecular-beam epitaxy and were fused by wafer fusion technique. Improvement of planarity and homogeneity over the thickness of heterointerface due to using optimized preliminary preparation of semiconductor wafer surfaces was demonstrated. No additional extended defects such as dislocations were found.
Fabrication and complex investigation of LAFE based on CNT by PECVD with island catalyst
Authors: Chumak M A , Rokacheva A A , Filatov L A , Kolosko A G , Filippov S V , Popov E O
Published: December 2021

This paper presents a study of large area field emitter based on carbon nanotubes grown by PECVD method on Si/SiO2 substrate with Fe catalyst. The catalyst was deposited by CVD on the substrate from ferrocene in the form of islands. The sample creation technology was described and results of the emission properties study were presented. Current-voltage characteristics were registered and tested for compliance with the cold field emission regime. The fluctuation statistic of effective microscopic parameters was constructed. Using data from a computerized field projector, the emission profile of the sample was calculated.
Creation of micro-and nanochannels on the surface of silicon chips by lithography methods and investigation of ion transport in channel
Authors: Afonicheva Polina , Lebedev Denis , Bukatin Anton , Mukhin Ivan , Evstrapov Anatoly
Published: December 2021

We developed a technique for fabrication microfluidic silicon-glass chips with a system of nanochannels connecting two microchannel using traditional optical lithography and a focused ion beam. To investigate the transport phenomena in the nanochannels we experimentally studied their ion conductivity and using optical microscopy confirmed the existence of the diffusion flow through them. The developed method allows us to create systems of nanochannels with on-purpose geometry and controlled sizes. Devices with such nanochannels can be applied in the creation of biosensor devices and for genetic studies.
Methods for measuring the local emission characteristics of CNT based multi-tip emitters
Authors: Popov E O , Kolosko A G , Filippov S V , Ponyaev S A
Published: December 2021

The work is aimed at obtaining microscopic emission characteristics of individual emission sites of a multi-tip field cathode or large-area emitter (LAFE) based on processing the current-voltage characteristics and emission glow patterns. Processing was carried out on a hardware-software complex for the study of field emission characteristics in real time. The calculation of the microscopic characteristics of the local emission sites — the field enhancement factor and emission area — was carried out by several different algorithms. A comparison of the results showed that the algorithms gave close values of the characteristics, which increases the reliability of the estimates made.
Thin nanocrystalline semiconductor films as selective chemical sensors for ammonia, acetone and other donors
Authors: Chistyakov V , Kazakov S , Grevtsev M , Solov’yov S
Published: December 2021

Studied are the films of variously doped polycrystalline n-semiconductors (ZnO, SnO2) as selective sensitive elements (SE) of chemical sensors for various gases and vapours (ammonia, acetone, propane, ethanol, hexane, solvent, turpentine etc.) in artificial air. It has been revealed that their conductivity changes under temperature modulation makes possible data processing which identifies the impurities above. This processing is based on nonlinear regression estimation of so called principal parameters which set is unique for every concentration of every of the gases/vapours.