bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-frequency noise characteristics of GaN vertical PIN diodes—Effects of design, current, and temperature
Authors: Ghosh Subhajit , Fu Kai , Kargar Fariborz , Rumyantsev Sergey , Zhao Yuji , Balandin Alexander A.
Published: December 2021

We report low-frequency noise characteristics of vertical GaN PIN diodes, focusing on the effects of the diode design, current, and temperature. The as-grown and regrown diodes, with and without surface treatment, have been studied. The noise in most of the GaN devices had a characteristic 1/f spectrum at high and moderate currents, while some devices revealed generation-recombination bulges at low currents (f is the frequency). The predominant trend of the noise spectral density, SI, dependence on the current was SI ∼ I. All tested GaN PIN diodes had rather low normalized noise spectral densities of 10−18–10−16 cm2/Hz (f = 10 Hz) at the current density J = 1 A/cm2 at room temperature. The noise temperature dependences at different currents revealed peaks at T = 375–400 K. Temperature, current, and frequency dependences of noise suggest that the noise mechanism is of the recombination origin. We argue that the noise measurements at low currents can be used to efficiently assess the quality of GaN PIN diodes.
Experimentally probing the extremes of droplet-on-demand printability via liquid metals
Authors: Watkins Nicholas N. , Elton Eric S. , Paul Phillip H. , Beck Victor A. , Jeffries Jason R. , Pascall Andrew J.
Published: December 2021

The liquid metal jetting droplet-on-demand technology provides many potential benefits to metal additive manufacturing. However, much is left to understand the operational margins to reliably create stable, satellite-free droplets. We elucidate these margins by experimentally probing the unexplored extremities of a recently proposed printability window based on the jet Weber (Wejet) and Ohnesorge (Z = 1/Oh) numbers. We generated stable droplets for 2 ≲ Wejet ≲ 4 for all tested Z = 339 to 2526—well beyond the bounds of any previously published printability window—suggesting that additional physics may be needed to understand droplet-on-demand in the high Z regime.
Introduction
Authors: Choe Regine , Xia Jun
Published: December 2021

Biomedical optical imaging techniques have been instrumental in advancing biology and medicine as they offer powerful methods to image living specimen and dynamic biological processes. Furthermore, innovations in optical imaging techniques have continuously expanded their potential in terms of imaging resolution, depth, contrast, and biomedical applications. In this chapter, the history of microscopy development starting from the inception of the microscope to the expansion into nano-scale resolution imaging with super-resolution imaging techniques is briefly outlined. Various optical imaging techniques such as optical coherence tomography, Raman imaging, diffuse optical/correlation tomography, diffuse fluorescence tomography, and photoacoustic tomography are introduced. In addition, the trade-off between imaging resolution and depth among imaging techniques, the advantages of optical imaging over non-optical imaging, and the organization of the book are discussed.
One-Photon Fluorescence Microscopy
Authors: Wang Depeng , Tian Yuqi , Gong Yiyang
Published: December 2021

One-photon fluorescence microscopy is an important biological and biomedical imaging technique. This chapter provides a comprehensive introduction of one-photon microscopy to help researchers maximize the effectiveness of their imaging experiments. This chapter first introduces fluorescence generation and the diffraction limit as background. It then outlines the basic operating principles of multiple one-photon microscopy configurations. Specific configurations include wide-field microscopy, light-field microscopy, confocal microscopy, light-sheet microscopy, and super-resolution microscopy. This chapter concludes by discussing multiple specific applications of one-photon fluorescence microscopy in neuroscience, matching the capabilities of the various microscope configurations with their role in obtaining novel information from biological samples.
Crystallization kinetics of atomic crystals revealed by a single-shot and single-particle X-ray diffraction experiment
Authors: Niozu Akinobu , Kumagai Yoshiaki , Hiraki Toshiyuki Nishiyama , Fukuzawa Hironobu , Motomura Koji , Bucher Maximilian , Asa Kazuki , Sato Yuhiro , Ito Yuta , You Daehyun , Ono Taishi , Li Yiwen , Kukk Edwin , Miron Catalin , Neagu Liviu , Callegari Carlo , Di Fraia Michele , Rossi Giorgio , Galli Davide Emilio , Pincelli Tommaso , Colombo Alessandro , Owada Shigeki , Tono Kensuke , Kameshima Takashi , Joti Yasumasa , Katayama Tetsuo , Togashi Tadashi , Yabashi Makina , Matsuda Kazuhiro , Bostedt Christoph , Ueda Kiyoshi , Nagaya Kiyonobu
Published: December 2021

Significance

Understanding the atomic-scale mechanism of crystallization is a fundamental issue in statistical mechanics and the basis for the synthesis of novel materials. We investigated the structures of single xenon nanoparticles at the early stage of formation by exploiting the femtosecond single-shot X-ray diffraction approach. We found the coexistence of a highly stacking-disordered structure and a stable face-centered cubic structure in the same single nanoparticles, suggesting that crystallization proceeds via an intermediate stacking-disordered phase. The results shine light on the early stages of condensed matter nucleation and demonstrate the effectiveness of the single-shot diffraction method for elucidating fast structural dynamics in atomic aggregates, feeding unique experimental information to nucleation and growth theory as well as to research and applications.
Sound-meaning relations in Japanese Tanka
Authors: Auracher Jan
Published: December 2021

This study aimed to test sound-meaning relations in Japanese poetry. To this end, participants assessed the sentiments expressed in a random selection of Tanka (a specific form of Japanese poetry) on six bipolar scales comprising Evaluation (emotional valence), Potency (dominance), and Activity (arousal). The selected Tanka differed with regard to their average formant-dispersion (i.e., the distance between the first and second formant). Corroborating results of a previous study that tested the relation between formant dispersion and emotional tone in German poetry, results suggest that poems with an extremely low average formant dispersion have a significantly higher likelihood of expressing dominance and activity than poems with an extremely high formant dispersion. No significant differences regarding the Evaluation dimension were found.
Variation in Spanish accounting terminology
Authors: García González Marta
Published: December 2021

The paper discusses the main results of an analysis of Spanish accounting terminology, based on the exploitation
of three different corpora. The analysis was aimed at measuring the level of terminology variation in Spanish accounting and at
assessing the suitability of accounting standards and companies’ financial statements for terminology extraction in the
translation of accounting texts. The results evidence a terminological variation of around 25% in international accounting
standards and a considerable lack of consistency in the use of accounting terminology in the financial statements of Spanish
companies, both in the Spanish originals and in their English translations.
Inhibition of ADAM17 impairs endothelial cell necroptosis and blocks metastasis
Authors: Bolik Julia , Krause Freia , Stevanovic Marija , Gandraß Monja , Thomsen Ilka , Schacht Sarah-Sophie , Rieser Eva , Müller Miryam , Schumacher Neele , Fritsch Jürgen , Wichert Rielana , Galun Eithan , Bergmann Juri , Röder Christian , Schafmayer Clemens , Egberts Jan-Hendrik , Becker-Pauly Christoph , Saftig Paul , Lucius Ralph , Schneider-Brachert Wulf , Barikbin Roja , Adam Dieter , Voss Matthias , Hitzl Wolfgang , Krüger Achim , Strilic Boris , Sagi Irit , Walczak Henning , Rose-John Stefan , Schmidt-Arras Dirk
Published: December 2021

Metastasis is the major cause of death in cancer patients. Circulating tumor cells need to migrate through the endothelial layer of blood vessels to escape the hostile circulation and establish metastases at distant organ sites. Here, we identified the membrane-bound metalloprotease ADAM17 on endothelial cells as a key driver of metastasis. We show that TNFR1-dependent tumor cell–induced endothelial cell death, tumor cell extravasation, and subsequent metastatic seeding is dependent on the activity of endothelial ADAM17. Moreover, we reveal that ADAM17-mediated TNFR1 ectodomain shedding and subsequent processing by the γ-secretase complex is required for the induction of TNF-induced necroptosis. Consequently, genetic ablation of ADAM17 in endothelial cells as well as short-term pharmacological inhibition of ADAM17 prevents long-term metastases formation in the lung. Thus, our data identified ADAM17 as a novel essential regulator of necroptosis and as a new promising target for antimetastatic and advanced-stage cancer therapies.
On the stability of recovering two sources and initial status in a stochastic hyperbolic-parabolic system
Authors: Wu Bin , Liu Jijun
Published: December 2021

Consider an inverse problem of determining two stochastic source functions and the initial status simultaneously in a stochastic thermoelastic system, which is constituted of two stochastic equations of different types, namely a parabolic equation and a hyperbolic equation. To establish the conditional stability for such a coupling system in terms of some suitable norms revealing the stochastic property of the governed system, we first establish two Carleman estimates with regular weight function and two large parameters for stochastic parabolic equation and stochastic hyperbolic equation, respectively. By means of these two Carleman estimates, we finally prove the conditional stability for our inverse problem, provided the source in the elastic equation be known near the boundary and the solution be in an a priori bounded set. Due to the lack of information about the time derivative of wave field at the final time, the stability index with respect to the wave field at final time is found to be halved, which reveals the special characteristic of our inverse problem for the coupling system.
A Si-based suspended tunnel structure with trapezoidal section by two-step etching
Authors: Ma Tieying , Wang Yipeng , Zhou Jinzhu
Published: December 2021

A two-step etching method is used to prepare a Si-based suspended tunnel structure with a trapezoidal section. In the first wet etching, surfactant Triton-X-100 is added to tetramethylammonium hydroxide (TMAH) enchant to inhibit crystal plane characteristics. Bulk Si Rib with trapezoidal cross section is formed, with inclination of side and height being modulated by changing etching time, to obtain good stability. After the SiO2 support layer is grown by thermal oxidation, pure 25% TMAH is used in the second wet etching to quickly lateral etch and undercut the bulk silicon under the support layer and form a suspended structure along <100> opening. Using additive-no additive two-step etching method, suspended structure with high stability and compressive strength, good insulation characteristics, high yield can be prepared. It lays a solid foundation for developing high sensitivity photo, thermal, chemical and gas sensors.
High-efficiency and tunable circular dichroism in chiral graphene metasurface
Authors: Cui Ying , Wang Xiaosai , Jiang Huan , Jiang Yongyuan
Published: December 2021

Circular dichroism (CD) response is extremely important for dynamic polarization control, chiral molecular sensing and imaging, etc. Here, we numerically demonstrated high-efficiency and tunable CD using a symmetry broken graphene-dielectric-metal composite microstructure. By introducing slot patterns in graphene ribbons, the metasurface exhibits giant polarization-selective absorption for circularly polarized (CP) wave excitations. The maximum CD reaches 0.87 at 2.78 THz, which originates from the localized surface plasmon resonances in patterned graphene. Besides, the operating frequency and magnitude of CD are dynamically manipulated by gating graphene’s Fermi energies. The proposed chiral graphene metasurface with high-efficiency and tunable capability paves a way to the design of active CD metasurfaces.
Metal-wire-embedded alumina insulating material using micro- and nanoscale 3D printing for surface flashover mitigation in a vacuum
Authors: Mu Haibao , Yao Yitong , Zhang Shu , Sun Guangyu , Guo Baohong , Song Falun , Cheng Yanlin , Zhang Guanjun
Published: December 2021

A micro- and nanoscale 3D printing technique is applied to fabricate a functional insulating material that mitigates surface discharge in a vacuum based on microscopic electron multipactor suppression. The proposed alumina ceramic insulator design consists of surface-embedded thin metal wires that introduce a local gradient of secondary electron emission (SEE) yield, such that the trajectories of multipactor electrons are distorted by accumulated negative surface charge and the SEE avalanche across the insulator surface becomes intermittent. Considerable increases of surface flashover threshold and surface charging reduction are verified by the experiment. Also, additional efforts are made to determine the optimal size and spatial distribution of the metal wire. A convex-shape flashover voltage trace is observed when increasing the width of the wire, suggesting a trade-off between the multipactor mitigation and the insulator strength. The wire’s position between the adjacent cathode triple junction and the middle of the insulator is proved to be favorable for flashover mitigation. The physical details of surface flashover mitigation by the proposed insulator design are revealed by an ab initio particle-in-cell simulation code, corroborating the experiment from a microscopic aspect.
Parallel directional coupler based dual-polarization electro-absorption modulator using epsilon near-zero material
Authors: Bhowmik Tanmay , Sikdar Debabrata
Published: December 2021

Electro-optical modulation, where a radio frequency signal can be encoded in an optical field, is crucial to decide the overall performance of an integrated photonics system. Due to the growing internet penetration rate worldwide, polarization-division-multiplexing (PDM) technique has emerged to increase the link capacity, where polarization-independent modulators are desirable to reduce system complexity. In this study, we propose a novel parallel directional coupler based dual-polarization electro-absorption modulator based on epsilon-near-zero (ENZ) material. The proposed design is capable of independent and synchronized modulation of two fundamental modes viz. transverse magnetic (TM) and transverse electric (TE) mode of a standard silicon (Si) rib waveguide. Indium-tin-oxide (ITO)–Si based two parallel hybrid plasmonic waveguides (HPW1 and HPW2) are placed such that fundamental TM (TE) mode of the input bus waveguide can be coupled to HPW1 (HPW2). The ENZ-state of ITO, acquired upon two independent electrical gating, enables large modulation depth by utilizing enhancement of electric field at the absorptive carrier accumulation layer. With a 27 μm active length, the extinction ratio (ER) of the proposed design is 10.11 dB (9.66 dB) for TM (TE) modulation at 1550 nm wavelength. This results in a 0.45 dB ER-discrepancy and indicates the polarization-insensitive nature of the modulator. The insertion losses and modulation bandwidths of our design are less than 1 dB and more than 100 GHz, respectively, for both polarizations over the entire C-band of wavelength. The proposed design can find potential applications in the PDM-enabled integrated photonics systems and high speed optical interconnections at data center networks.
The Ξ-nuclear potential constrained by recent Ξ− hypernuclei experiments
Authors: Hu Jinniu , Zhang Ying , Shen Hong
Published: December 2021

The Ξ-nuclear potential is investigated in the quark mean-field (QMF) model based on recent results on the Ξ− + 14N (

C

Ξ

−

15

) system. The experimental data on the binding energy of 1p-state Ξ− hyperon in

C

Ξ

−

15

hypernuclei in KISO, IBUKI, E07-T011, E176-14-03-35 events are merged as

B

Ξ

−

(

1
p

)

=
1.14
±
0.11

MeV. With this constraint, the coupling strengths between the ω vector meson and Ξ hyperon are fixed in three QMF parameter sets. At the same time, the Ξ− binding energy of 1s state in

C

Ξ

−

15

is predicted as

B

Ξ

−

(

1
s

)

=
5.66
±
0.38

MeV with the same interactions, completely consistent with the data from the KINKA and IRRAWADDY events. Finally, the Ξ-nuclear potential is calculated in the symmetric nuclear matter in the same framework. It is found to be U
Ξ = −11.96 ± 0.85 MeV at nuclear saturation density, which is important for the discussions of the role of strangeness in a neutron star.
Aperiodic crystals in biology
Authors: Maciá Enrique
Published: December 2021

Biological systems display a broad palette of hierarchically ordered designs spanning over many orders of magnitude in size. Remarkably enough, periodic order, which profusely shows up in non-living ordered compounds, plays a quite subsidiary role in most biological structures, which can be appropriately described in terms of the more general aperiodic crystal notion instead. In this topical review I shall illustrate this issue by considering several representative examples, including botanical phyllotaxis, the geometry of cell patterns in tissues, the morphology of sea urchins, or the symmetry principles underlying virus architectures. In doing so, we will realize that albeit the currently adopted quasicrystal notion is not general enough to properly account for the rich structural features one usually finds in biological arrangements of matter, several mathematical tools and fundamental notions belonging to the aperiodic crystals science toolkit can provide a useful modeling framework to this end.
Coarse-grained tight-binding models
Authors: Liu Tian-Xiang , Mao Li , Pistol Mats-Erik , Pryor Craig
Published: December 2021

Calculating the electronic structure of systems involving very different length scales presents a challenge. Empirical atomistic descriptions such as pseudopotentials or tight-binding models allow one to calculate the effects of atomic placements, but the computational burden increases rapidly with the size of the system, limiting the ability to treat weakly bound extended electronic states. Here we propose a new method to connect atomistic and quasi-continuous models, thus speeding up tight-binding calculations for large systems. We divide a structure into blocks consisting of several unit cells which we diagonalize individually. We then construct a tight-binding Hamiltonian for the full structure using a truncated basis for the blocks, ignoring states having large energy eigenvalues and retaining states with energies close to the band edge energies. A numerical test using a GaAs/AlAs quantum well shows the computation time can be decreased to less than 5% of the full calculation with errors of less than 1%. We give data for the trade-offs between computing time and loss of accuracy. We also tested calculations of the density of states for a GaAs/AlAs quantum well and find a ten times speedup without much loss in accuracy.
Collective cloaking of a cluster of electrostatically defined core–shell quantum dots in graphene
Authors: Sadrara Mahdiyeh , Miri MirFaez
Published: December 2021

We study cloaking of a cluster of electrostatically defined core–shell quantum dots in graphene. Guided by the generalized multiparticle Mie theory, the Dirac electron scattering from a cluster of quantum dots is addressed. Indeed distant quantum dots may experience a sort of individual cloaking. But despite the multiple scattering of an incident electron from a set of adjacent quantum dots, collective cloaking may happen. Via a proper choice of the radii and bias voltages of shells, two most important scattering coefficients and hence the scattering efficiency of the cluster dramatically decrease. Energy-selective electron cloaks are realizable. More importantly, clusters simultaneously transparent to electrons of different energies, are achievable. Being quite sensitive to applied bias voltages, clusters of core–shell quantum dots may be used to develop switches with high on-off ratios.
Topological phonons and electronic structure of Li2BaSi class of semimetals
Authors: Sharma Vineet Kumar , Singh Birender , Sarkar Anan Bari , Gupta Mayanak K , Mittal Ranjan , Agarwal Amit , Singh Bahadur , Kanchana V
Published: December 2021

Extension of the topological concepts to the bosonic systems has led to the prediction of topological phonons in materials. Here we discuss the topological phonons and electronic structure of Li2BaX (X = Si, Ge, Sn, and Pb) materials using first-principles theoretical modelling. A careful analysis of the phonon spectrum of Li2BaX reveals an optical mode inversion with the formation of nodal line states in the Brillouin zone. Our electronic structure results reveal a double band inversion at the Γ point with the formation of inner nodal-chain states in the absence of spin–orbit coupling (SOC). Inclusion of the SOC opens a materials-dependent gap at the band crossing points and transitions the system into a trivial insulator state. We also discuss the lattice thermal conductivity and transport properties of Li2BaX materials. Our results show that coexisting phonon and electron nontrivial topology with robust transport properties would make Li2BaX materials appealing for device applications.
A new multipath channel estimation and mitigation using annihilation filter combined tracking loop implementation in software GPS receivers
Authors: Elango G Arul , Jr René
Published: December 2021

The multipath effect causes severe degradation in the positioning of commercial GPS receivers. Due to multipath error, the positioning accuracy could reach a few of 10 m. If the cumulative Multipath delay is less than 0.1–0.35 chips, then it is difficult to mitigate in GPS receivers. This causes severe degradation in GPS signals and can cause a measurement bias. To alleviate this problem, the estimation of multipath parameters using annihilating filter and its mitigation in the GPS tracking loop is proposed in this work. The estimation of randomly generated multipath signals can be performed in the receiver with a lower sampling rate when compared to the larger bandwidth of the GPS baseband signal. Here, the frequency components of the multipath signal in superimposed complex exponentials have been transformed from the time delay and the amplitude of the path observables. The Rayleigh fading model in the urban scenario has been simulated in which the amplitude and the phase of the number of paths (i.e. the frequency component of superimposed complex exponentials) are set and this fading signal is convolved with GPS signal that forms the multipath faded signal. In the GPS receiver post-processing stage, with the help of the annihilation filter, the multipath components are estimated, then an inverse/adaptive filter and compensation technique are further applied to mitigate the multipath component. The mean square error with the different number of paths with noisy environments is analyzed utilizing the cadzow denoising algorithm. The simulation results of the proposed technique employed in the tracking module of the software GPS receiver under severe multipath conditions indicate a substantial enhancement in the performance of the GPS receiver with minimal code and carrier phase error when compared to the least squares and adaptive blind equalization channel techniques. Moreover, the positioning accuracy is also calculated with the inclusion of multipath components in two satellites out of six satellites used in the simulation, the results showed that the annihilation filter improved the mean position accuracy up to 9.3023 m.
Quantitative and nondestructive determination of residual stress for SiO2 thin film by laser-generated surface acoustic wave technique
Authors: Zhang Li , Xiao Xia , Qi Haiyang , Huang Yiting , Qin Huiquan
Published: December 2021

The laser-generated surface acoustic wave (SAW) technique is a promising method to measure the mechanical properties of thin films quickly and nondestructively. Residual stress is inevitable during the processing and manufacturing of integrated circuits, which will have a major impact on the physical and mechanical properties of the thin film materials and cause deterioration to the structural strength. In this study, the SAW technique based method is proposed for quantitative and nondestructive measuring the residual stress in the nanostructured films. The method is verified by the experiment measuring the SiO2 films in the thickness range of 100–2000 nm. The experimental procedures, including signal excitation, reception and processing, are described in detail. By matching the SAW experimental dispersion curve with the calculated theoretical dispersion curve containing the residual stress, the residual stress of the SiO2 films along [110] and [100] crystallographic orientation of the Si wafer is successfully quantified. The determination results are ranged from −65.5 to 421.1 MPa and the stress value increases as the film thickness decreases, revealing the residual stress of the SiO2 film is compressive. Meanwhile, the conventional substrate curvature method as a comparison is used to verify the correctness and superiority of the proposed SAW method for the residual stress determination.
Efficient gradient computation for optimization of hyperparameters
Authors: Xu Jingyan , Noo Frederic
Published: December 2021

We are interested in learning the hyperparameters in a convex objective function in a supervised setting. The complex relationship between the input data to the convex problem and the desirable hyperparameters can be modeled by a neural network; the hyperparameters and the data then drive the convex minimization problem, whose solution is then compared to training labels. In our previous work (Xu and Noo 2021 Phys. Med. Biol.
66 19NT01), we evaluated a prototype of this learning strategy in an optimization-based sinogram smoothing plus FBP reconstruction framework. A question arising in this setting is how to efficiently compute (backpropagate) the gradient from the solution of the optimization problem, to the hyperparameters to enable end-to-end training. In this work, we first develop general formulas for gradient backpropagation for a subset of convex problems, namely the proximal mapping. To illustrate the value of the general formulas and to demonstrate how to use them, we consider the specific instance of 1D quadratic smoothing (denoising) whose solution admits a dynamic programming (DP) algorithm. The general formulas lead to another DP algorithm for exact computation of the gradient of the hyperparameters. Our numerical studies demonstrate a 55%–65% computation time savings by providing a custom gradient instead of relying on automatic differentiation in deep learning libraries. While our discussion focuses on 1D quadratic smoothing, our initial results (not presented) support the statement that the general formulas and the computational strategy apply equally well to TV or Huber smoothing problems on simple graphs whose solutions can be computed exactly via DP.
An overview of tritium retention in dust particles from the JET-ILW divertor
Authors: Otsuka T , Masuzaki S , Ashikawa N , Torikai Y , Hatano Y , Tokitani M , Oya Y , Asakura N , Hayashi T , Tanigawa H , Iwai Y , Widdowson A , Rubel M
Published: December 2021

Tritium (T) retention characteristics in dust collected from the divertor in JET with ITER-like wall (JET-ILW) after the third campaign in 2015–2016 (ILW-3) have been examined in individual dust particles by combining radiography (tritium imaging plate technique) and electron probe micro-analysis. The results are summarized and compared with the data obtained after the first campaign in 2011–2012 (ILW-1). The dominant component in ILW-1 dust was carbon (C) originating from tungsten-coated carbon fibre composite (CFC) tiles in JET-ILW divertor and/or legacy of C dust after the JET operation with carbon wall. Around 85% of the total tritium retention in ILW-1 dust was attributed to the C dust. The retention in tungsten (W) and beryllium (Be) dominated particles was 100 times smaller than the highest T retention in carbon-based particles. After ILW-3 the main component contributing to the T retention was W. The number of small W particles with T increased, in comparison to ILW-1, most probably by the exfoliation and fragmentation of W coatings on CFC tiles though T retention in individual W particles was smaller than in C particles. The detection of only very few Be-dominated dust particles found after ILW-1 and ILW-3 could imply stable Be deposits on the divertor tiles.
Exploration of interacting dynamical dark energy model with interaction term including the equation-of-state parameter: alleviation of the H0 tension
Authors: Guo Rui-Yun , Feng Lu , Yao Tian-Ying , Chen Xing-Yu
Published: December 2021

We explore a scenario of interacting dynamical dark energy model with the interaction term Q including the varying equation-of-state parameter w. Using the data combination of the cosmic microwave background, the baryon acoustic oscillation, and the type Ia supernovae, to global fit the interacting dynamical dark energy model, we find that adding a factor of the varying w in the function of Q can change correlations between the coupling constant β and other parameters, and then has a huge impact on the fitting result of β. In this model, the fitting value of H
0 is lower at the 3.54σ level than the direct measurement value of H
0. Comparing to the case of interacting dynamical dark energy model with Q excluding w, the model with Q including the constant w is more favored by the current mainstream observation. To obtain higher fitting values of H
0 and narrow the discrepancy of H
0 between different observations, additional parameters including the effective number of relativistic species, the total neutrino mass, and massive sterile neutrinos are considered in the interacting dynamical dark energy cosmology. We find that the H
0 tension can be further reduced in these models, but is still at the about 3σ level.
Linear time-delay circuit and stabilizing controller
Authors: Cong Yuhao , Zhang Yong , Hu Guang-Da
Published: December 2021

This paper is concerned with a linear time-delay circuit and its feedback control. We use electronic components such as resistors and capacitors to realize a linear time-delay system. The time-delays are generated by operational amplifiers and single-chip microcomputers. Based on the actual data measured by the oscilloscope, the parameters of the system are estimated using the least square method. Then a comparison study between the waveform image measured by the oscilloscope and the numerical simulation obtained by MATLAB verifies the effectiveness of the parameters estimations of the circuit system. Furthermore, the circuit system is unstable with a large time-delay, a feedback controller is designed to stabilize the circuit system using the optimization method in the literature. Finally, the experimental results in the linear time-delay circuit show the effectiveness of the optimization method.
Experimental demonstration of ghost imaging with speckled light in long-wavelength infrared range
Authors: Khasanov I Sh
Published: December 2021

Infrared imaging with a single-pixel camera can achieve radiometric accuracy not currently available with multi-pixel thermal cameras. One of the actively investigated single-pixel camera technology is ghost imaging. We propose an optical design to experimentally demonstrate classical ghost imaging in the long-wave infrared frequency range with speckled light without using a spatial light modulator. We obtained an example low-quality ghost image and then used the cross-correlation function to identify and explain the main difficulties in ghost imaging with a thermal camera.
Contribution of wave aberrations represented by Zernike polynomials to the cross-correlation function between distorted and actual speckle patterns
Authors: Blagova T V , Khasanov I Sh
Published: December 2021

Speckles are sensitive to the slightest inhomogeneities of the medium, which is used in optical research methods such as speckle interferometry. However, the stochastic nature of propagation of speckle fields complicates their accurate detection and processing. For example, aberrations in the optical system result in the decorrelation of the image of speckles with the actual speckles that are observed in free space. The report will consider the main types of wave aberrations of optical system and their influence on the correlation properties of speckle patterns. The research results can be used to optimize optical systems in which speckles play a significant role, for example, in classical ghost imaging.
Methodology for identifying gaseous constituents of the atmosphere
Authors: Krasnov A E , Ryzhkova D Yu , Vagin V A
Published: December 2021

Methodology for the analysis of concentrations of gaseous composite of atmosphere by the corresponding infrared (IR) spectrum, measured with the help of trajectory spectroradiometers (TSR) is observed. The developed algorithm for mathematical processing of the measurement results is briefly described, including the detection and estimation of the concentrations of the sought gases using the notch filtration of their spectral components, which makes it possible to significantly reduce the concentration identification error. The spectra of various substances in the mid-IR range are considered, and the results of approbation of the technique based on the TSR model with an external high-temperature radiation source on a 1 m path are presented.
Composite thin films based on multilayer carbon nanotubes and calcium phosphate with electrical conductive properties for bone tissue engineering
Authors: Zhovnir S Z , Savelyev M S , Kuksin A V , Kurilova U E , Gerasimenko A Yu , Fedotov A Yu , Lobzhanidze P V , Komlev V S
Published: December 2021

This work is aimed at developing of electrically conductive composite thin films based on calcium phosphates (CP) and multi-walled carbon nanotubes (MWCNT) for bone tissue engineering. A method based on the sputtering of an dispersion of CPs and MWCNTs on a substrate with subsequent exposure to a laser with different power values to form connected networks of nanotubes has been proposed. It is shown that the electrical conductivity of CP/MWCNT films reaches high values for dispersions with a MWCNT concentration of 1 mg/ml when exposed to laser radiation with a power of 2.1–3.0 W. It was found that ablation areas of CPs and MWCNTs as a result of exposure to a high-power laser are found in areas of the film with increased resistance.
Problems and methods of a closed-loop blood glucose control system construction
Authors: Litinskaia E L , Pozhar K V , Zhilo N M
Published: December 2021

The automation of the insulin therapy in the closed-loop blood glucose control system is accompanied by such problems as delays of the feedback and the controlling action effect on blood glucose dynamics, difficulties in low and high glucose levels advance detection and timely compensation, a human factor, complexity of a mathematical model of control object building, evaluation of blood glucose control efficiency. In the paper, these automation problems and methods for their compensation are considered. The closed-loop system based on the model predictive control, adaptive adjustment of the controlling action and decision-making support was developed. Experimental testing with UVA/Padova Type 1 Diabetes Mellitus Simulator showed that the application of suggested methods in the closed-loop allows increasing the efficiency of the blood glucose maintaining in the target range.
Lumped parameter model of the cardiovascular system with baroreflex
Authors: Rubtsova E , Telyshev D
Published: December 2021

The patient’s activity directly affects the state of the cardiovascular system (CVS). One of the mechanisms contribute to the regulation of the arterial blood pressure is the baroreflex. It is maintains an optimal level of the arterial pressure as a response to changes in the patient’s activity. The model developed in this work simulates CVS at the different patient’s activity levels. The model of baroreflex reproduces changes that occur during an increasing level of patient’s activity. The correlation between heart rate (79 bpm –rest, 123 bpm – exercise) and cardiac output (5.1 l/min –rest, 8.2 l/min – exercise) was achieved. The developed model can be used for personal modelling of various states of the CVS. The model parameters possible to apply for individual patient characteristics. For further development, the model can be integrated with the ventricular assist device during the heart failure state in order to study interactions in the biotechnical system.
Investigating the reliability of all-optical switches in transient mode
Authors: Barabanova E A , Vytovtov K A , Vishnevsky V M , Dvorkovich A V , Shurshev V F
Published: December 2021

In this paper the scheme of 8×8 all-optical switch with two duplicating switching elements and the algorithm of its functioning are presented. For calculating the reliability of all-optical switches, the analytical method based on the Markov process theory is presented. This method allows us to calculate reliability indicators of the all-optical switches as downtime coefficient and availability factor in stationary and transient modes and time of transient mode. The results of numerical calculations show that an increase in the number of duplicating elements by one gives decrease in the downtime coefficient by 6 percent, and the time of the transient process is halved in this case.
Application of acoustic microscopy for evaluation of numismatic material
Authors: Petronyuk Y S , Titov S A , Levin V M
Published: December 2021

A new non-destructive express method for assessing the authenticity of numismatic material is considered in the paper. Non-destructive methods of pulsed acoustic microscopy in the frequency range of 50-100 MHz were applied. Samples of silver coins dated 1924 and 1979 were examined. The characteristic values of the longitudinal and transverse sonic velocity of the samples were obtained. The method of hydrostatic weighing was used to measure the density of the metal. It was shown that assessment of the authenticity and the safety degree of coins can also be carried out by revealing the internal defects such as corrosion. Acoustic visualization in the reflection mode allows imaging the offset of the obverse relative to the reverse and to determine the centre of the coin deviation, which also confirms the quality of the minting.
Mathematical modeling of the eddy current testing of delamination cracks in multilayer CFRP objects
Authors: Shkatov P N
Published: December 2021

We propose an approximate mathematical model making it possible to obtain estimates of the change in the eddy current signal under the influence of delamination in multilayer carbon fiber reinforced plastic (CFRP) objects. We give the dependences of the change in the eddy current signal on delamination in the CFRP objects for a new flaw detection method based on the comparison of eddy current signals from CFRP layers grouped by angular orientation.
Assessment automation of road traffic safety with account for road conditions of an individual itinerary
Authors: Skorobogatchenko D A , Borovik V V , Frolovichev A I
Published: December 2021

The paper substantiates the need to develop an automated system for traffic safety assessment in urban agglomerations, taking into account road conditions. The authors suggest a methodology for assessment of road traffic accidents, which makes it possible to take into account a wide range of factors affecting them. The methodology is based on complementing the traditional approach of final accident rate calculation with algorithms for collecting and analyzing data using Big Data tools, in particular, convolutional neural networks, fuzzy neural networks such as ANFIS, and cluster analysis using the k-means method. All accident rates are grouped according to the principle of homogeneity of acquisition of information for their calculation. Further, one of the data processing tools is applied to each group. As a result, labor intensity is reduced and the effectiveness of the application of the method of final accident rates increases. For practical calculations, the authors have developed a client-server application that uses data on geometric characteristics, current traffic situation, weather and climatic effects at the time of the trip along a specific itinerary. By means of application use, the analysis of traffic safety on a number of routes in Volgograd was carried out and the results are presented in comparison with the calculations made via the traditional method. It is shown that the use of information about the current situation on a specific section of the road network in terms of the current time significantly increases the accuracy of calculations.
The decision support system for conducting fire-prevention measures in woodlands
Authors: Sorokin A A , Maltseva N S , Puzankov D S , Shurshev V F , Galimova L V
Published: December 2021

Purpose of the work is to propose provisions for the aggregation of parameters of a climatic and anthropogenic nature. Regulations are necessary to determine the rating of forest areas in terms of fire hazard level. As a result of the study, theoretical provisions for the aggregation of variables have been proposed. Variables are described on different metric scales and affect the final result in different ways. The provisions are based on the methods of the theory of fuzzy sets and fuzzy inference. The computational complex for determining the rating of the forest areas is implemented in the form of a hierarchical system of fuzzy inference. It is based on the Takagi-Sugeno algorithm. Simulation of the complex operation was carried out. As a result, it was concluded that the generated output pattern has a stepped nature. This makes it possible to classify the analyzed elements into state groups. This allows you to solve the problems of planning work on the implementation of preventive and/or preparatory measures to eliminate or prevent forest fires. The prospect of further research is the formation of decision support systems in the control processes organization of forest areas.
Application of methods of multidimensional statistical analysis for the classification of signal fragments during cutting processing
Authors: Belov A V , Trufanov N N , Churikov D V , Kravchenko O V
Published: December 2021

The preliminary processing of the signal coming from the vibration sensor is performed. Spectral analysis methods allow identifying the distinctive zones corresponding to three parameters: the average amplitude of vibrations, the average value of the spectrum, and the complex parameter of the vibration density obtained using interpolation methods. Hence, the vector contains the listed parameters as components produce a vector space, and the equations of separating surfaces in three-dimensional space and classification errors are calculated.
The effect of shape and sizes of particles of wet quartz powders on complex dielectric permittivity in the frequency range of 10 kHz – 10 GHz
Authors: Bobrov P P , Kroshka E S , Rodionova O V
Published: December 2021

The results of experimental studies of complex dielectric permeability of river sand and powders of granules of fused quartz with narrow distributions of particles in size at the frequencies from 10 kHz to 10 GHz are presented. The granule particles are spheres and the sand particles are irregularly shaped. The samples were moistened with distilled water and NaCl salt solution with conductivity of 0.1 and 0.77 S/m. It has been shown that the shape of the particles affects the complex dielectric permittivity (CDP) in the low frequency part of the range only when proportion of the solution is small and its concentration is weak. At full saturation of the samples with the solution and its high concentration, as well as in all cases at frequencies above 100 MHz, the influence of the particle shape is small. In the mid-frequency part of the range (from units to tens of megahertz) in a sample of quartz granules with small particles, there is a strong relaxation process, leading to a significant increase in the real part of the CDP. A similar, but slight increase is observed in samples of sand with larger particles. In the high-frequency range, the effect of the shape and particle sizes is very weak.
Electromagnetic response from composite carbon-containing structures with technological inhomogeneities at EHF
Authors: Trofimov E A , Kuleshov G E , Moskalenko V D , Badin A V , Dorozhkin K V
Published: December 2021

The results of studies of the electromagnetic response from composite structures made of a carbon-containing polymer with the inclusion of spherical pores in the bulk of the material and with pyramidal corrugation on the surface of the material are presented. The results of modeling the frequency dependences of the transmission, reflection and absorption coefficients in the EHF range are shown. Samples of composite carbon-containing structures with technological inhomogeneities have been fabricated by 3D printing. Measurements of the electromagnetic response from experimental samples were carried out in the frequency range from 100 to 1000 GHz. At frequencies up to 250 GHz, the inclusion of air pores in the polymer volume reduces the transmission coefficient, practically does not affect the reflection, and increases the absorption. Pyramid corrugated material absorbs more than 99% of radiation in the frequency range from 200 to 635 GHz.
Quantum-mechanical model of dielectric losses in nanometer layers of solid dielectrics with hydrogen bonds at ultra-low temperatures
Authors: Kalytka V A , Mekhtiev A D , Sh Madi P , Bashirov A V
Published: December 2021

Upon based the finite difference methods construct the solutions for Liouville quantum kinetic equation linearized by the external field, in complex with the stationary Schrodinger equation and the Poisson operator equation, for an ensemble of non-interacting hydrogen ions (protons) migrating in the field of a crystal lattice perturbed by a variable polarizing field. The influence of the phonon subsystem is not taken into account. The equilibrium (non-balanced) proton density matrix is calculated using quantum Boltzmann statistics. The temperature spectra of dielectric losses tangent angle for hydrogen bonded crystals (HBC) in a wide temperature range (50–550 K) are calculated. At the theoretical level detected the effects of nano-crystalline states (1–10 nm) during the polarization of HBC in the region of ultra-low temperatures (4–25 K).
Realization of actions of characters and combustion process in the system of 3D modeling of the evacuation process
Authors: Tugarinov M A , Shulga I D , Yurchenko E A , Torgaev S N
Published: December 2021

The article presents the results of action modules software implementation in the 3D modeling system of the evacuation process in emergency situations. In particular, the software implementation of such actions of the model characters as organizing a group for evacuation, providing assistance to the victim, taking measures to extinguish the fire is presented. The article also presents the physicochemical properties of materials that are taken into account in model for simulating combustion and smoke formation processes. The software implementation is based on the Unreal Engine program and using automatic descriptions of the physical and psychological states of the characters. The descriptions of the possibility of creating characters in the model with different physical and psychological parameters and collecting statistical data on their condition are given.