bluuebunny/crossref_metadata_2025 huggingface dataset:
1/f Noise in epitaxial sidewall graphene nanoribbons
Authors: Vail O. , Hankinson J. , Berger C. , de Heer W. A. , Jiang Z.
Published: August 2020

We perform gate- and temperature-dependent low-frequency noise measurements on epitaxial graphene nanoribbons (epiGNRs) grown on the sidewalls of trenches etched in SiC substrates. We find that the measured noise spectra are dominated by 1/f noise, and the main source of the noise at high carrier densities is the long-range scatters (charge traps) at the epiGNR/gate-dielectric interface. Interestingly, our findings differentiate sidewall epiGNRs from previously studied lithographically patterned GNRs while exhibiting competitive noise characteristics similar to those in high-quality suspended graphene or graphene on hexagonal boron nitride substrates. These results provide confidence in potential epiGNR-based device applications in low-noise nanoelectronics.
Dynamics of nonisothermal two-thin-fluid-layer systems subjected to harmonic tangential forcing under Rayleigh–Taylor instability conditions
Authors: Sterman-Cohen Elad , Oron Alexander
Published: August 2020

The stability of a nonisothermal system consisting of two superimposed fluid layers: a thin liquid film layer and a gas layer sandwiched between differentially heated horizontal solid plates in the gravity field, is investigated. The system is assumed to be subjected to the Rayleigh–Taylor instability (RTI) with the Marangoni effect that either enhances the RTI or opposes it and to the tangential harmonic vibration of the upper substrate. A set of reduced evolution equations is derived based on the weighted-residual integral boundary layer approach, and the investigation is carried out in the framework of this set. The base state of the system represents a time-periodic flow, and its linear stability analysis is carried out using the Floquet theory in the large-time limit. The nonlinear dynamics of the system is investigated numerically in the case of either a static or vibrating substrate. Among the possible outcomes of the nonlinear dynamics, there is the emergence of ruptured states of the liquid film with rupture taking place at either the upper or lower substrate and also the emergence of saturated continuous flows of the liquid film. We also find that the nonlinear dynamics of the system is consistent with the results of the linear stability analysis in terms of enhancement or attenuation of interfacial distortion.
Measurement accuracy and spatial resolution of a distributed temperature sensor based on a two-pulse differential coherent reflectometer
Authors: Lukashova T.O. , Nanii O.E. , Nikitin S.P. , Treshchikov V.N.
Published: August 2020

We present a model and numerical simulation of a distributed temperature sensor based on a two-pulse differential coherent optical time-domain reflectometer (COTDR). The differential phase measured using a phase-sensitive Rayleigh reflectometer is shown to have a regular component, which is a linear function of temperature, and a random component, which is related to a random distribution of scattering centres in the fibre and restricts the accuracy of measurements of variations in temperature. Measurement accuracy can be improved by reducing the relative contribution of the random component via a decrease in pulse duration and/or an increase in the time delay between pulses. The spatial resolution of a differential two-pulse phase-sensitive reflectometer is shown to be determined by the time delay between pulses and to vary little with pulse duration. At a typical pulse duration (200 ns) and delay time (300 ns), the accuracy in measurements of variations in temperature in the 0.1-K range is 2 % and the spatial resolution is about 30 m.
Peculiarities of adaptive phase correction of optical wave distortions under conditions of ‘strong’ intensity fluctuations
Authors: Lukin V.P. , Botygina N.N. , Emaleev O.N. , Lavrinov V.V.
Published: August 2020

The reason for the loss of efficiency of adaptive phase correction in the propagation of optical waves in a turbulent atmosphere under conditions of ‘strong’ intensity fluctuations is experimentally explained for the first time. Based on the data from experiments conducted on both horizontal and vertical atmospheric paths, we have found that intensity fluctuations begin to significantly affect phase measurements when the coherence radius of the optical wave becomes less than the radius of the first Fresnel zone. Under these conditions, the main meter of adaptive optics systems, i. e. the Hartmann sensor, no longer provides correct measurements of the phase distribution in the presence of deep amplitude modulation. Based on the study of the behaviour of the mode components of the phase fluctuations reconstructed from the results of measurements in various operating regimes, we have found that, first of all, the amplitudes of the lowest modes of phase fluctuation expansion (tilts, defocusing, and astigmatism) are distorted, which, as the analysis shows, is very different from the regime of weak fluctuations.
Unipolar light: existence, generation, propagation, and impact on microobjects
Authors: Arkhipov R.M. , Arkhipov M.V. , Rosanov N.N.
Published: August 2020

A review is presented of recent works on optical unipolar pulses, whose electric area (integral of the electric field strength over time) is nonzero, which determines the predominant direction of the electric field strength. It is shown that the existence of unipolar pulses does not contradict Maxwell’s equations, and that unipolar pulses can propagate in waveguides. It is emphasised that, along with the spectral, energy, and polarisation parameters, the electric area of short light pulses is also an important characteristic. The unidirectional action of these pulses on microobjects indicates that it is promising to develop methods for generating radiation with such properties. We disciuss methods for the generation, propagation, and interaction of unipolar light with classical and quantum systems, as well as methods for recording the electric area of light pulses.
Compact ultrastable laser system for spectroscopy of 2S1/2 → 2D3/2 quadrupole transition in 171Yb+ ion
Authors: Zalivako I.V. , Semerikov I.A. , Borisenko A.S. , Aksenov M.D. , Vishnyakov P.A. , Sidorov P.L. , Semenin N.V. , Golovizin A.A. , Khabarova K.Yu. , Kolachevsky N.N.
Published: August 2020

We report the results of studying a compact laser system designed for manipulating a quantum state of the optical qubit based on the 2S1/2 → 2D3/2 quadrupole transition in the 171Yb+ ion at a wavelength of 435.5 nm. An emission power of the laser system reaches 500 μW at λ = 435.5 nm and the relative frequency instability of at most 3 × 10−15 is achieved at averaging intervals from 0.5 to 50 s with a subtracted linear frequency drift. The compactness of the developed system makes it possible to employ it in transportable systems including optical clocks.
Superluminescent diodes in the spectral range of 1.5 – 1.6 μm based on strain-compensated AlGaInAs/InP quantum wells
Authors: Sabitov D.R. , Ryaboshtan Yu.L. , Svetogorov V.N. , Padalitsa A.A. , Ladugin M.A. , Marmalyuk A.A. , Vasil’ev M.G. , Vasil’ev A.M. , Kostin Yu.O. , Shelyakin A.A.
Published: August 2020

Superluminescent diodes based on AlGaInAs/InP separate-confinement double heterostructures with strain-compensated quantum wells are investigated. The influence of elastic strains in the active region on the output characteristics of the devices is analysed. It is shown that such a design of a superluminescent diode allows an optical power of more than 5 mW, a radiation spectrum width of more than 60 nm, a degree of output radiation polarisation up to 30 dB to be obtained at the output of a single-mode fibre, and has a great potential for further improvement.
Corrigendum to: Fish in the matrix: effects of landscape on community-structure patterns of the ichthyofauna
of streams in Cerrado
Authors: Vieira Thiago Bernardi , Brasil Leandro Schlemmer , Raiol Torres Naiara , Lima de Melo Tatiana , Moreira Elto Aparecido , Bastos Rogério Pereira , Dias-Silva Karina
Published: August 2020

This study aims to identify species richness and composition patterns of the ichthyofauna in different landscape matrices (forest, pasture and eucalypt crops) and to evaluate the variation of species composition in different matrices, identifying possible indicator species. We selected 21 streams; 7 were surrounded by native vegetation, 9 surrounded by pasture and 5 by eucalypt crops. We tested whether there was difference in the composition and species richness. In addition, we used the indicator value (IndVal) to verify if there were species faithful and specific to some land use and land cover. Streams located in forest presented the highest estimated species richness, followed by streams in pasturelands and eucalypt matrices. There was no difference between the composition of fishes in different matrices, but we observed a relationship between Phenacorhamdia somnians (Mees, 1974) and pasture matrix. The results indicated that the change in land use may benefit some generalist species such as Phenacorhamdia somnians.
An observational study of the acceptability of patient-delivered partner therapy for management of chlamydia
Authors: Woodward Shannon C. , Tyson Hayley A. , Martin Sarah J.
Published: August 2020

Partners of heterosexual cases with chlamydia, who were identified as having difficulty in attending the clinic, were offered patient-delivered partner therapy (PDPT). Medication was delivered by the index case after telephone consultation with the partner to assess symptoms and medical history. The opportunity for testing of partners for chlamydia was provided. The PDPT process was evaluated by standardised phone interview with index patients and partners. Telephone consultation enables safe medication prescribing and an opportunity for further contact tracing. Partners were unlikely to seek testing when provided with PDPT. Delivery of medication resulted in a reported rate of treatment of 100%. PDPT was an acceptable treatment option to both index and partner and should be considered if legislation permits.
ROS-mediated synthetic growth defect caused by impaired metabolism of sphingolipids and phosphatidylserine in budding yeast
Authors: Toda Takumi , Urita Atsuya , Koga Ayano , Takayama Chihiro , Tani Motohiro
Published: August 2020

Previously, we found that yeast exhibits a strong growth defect with the combination of a lack of gene involved in structural modification of sphingolipids and repression of the phosphatidylserine synthase gene. Here we found that the double gene mutation causes reactive oxygen species-mediated cell growth defect, which is suppressed by deletion of LEM3 encoding the subunit of phospholipid flippase.
ECC meets CEU—New focus on the backdoor for calcium ions in skeletal muscle cells
Authors: Melzer Werner
Published: August 2020

In this issue, Michelucci et al. report the existence of specific sites acting as Ca2+ entry units (CEUs) in fast skeletal muscle of mice lacking calsequestrin (CASQ1), the major Ca2+ binding protein of the SR. The CEU provides constitutive and store-operated Ca2+ entry (SOCE) and resistance to force decline resulting from SR Ca2+ depletion during repetitive muscle activity.
Critical heat engines in massive gravity
Authors: Yerra Pavan Kumar , Bhamidipati Chandrasekhar
Published: August 2020

With in the extended thermodynamics, we study the efficiency η

k
of critical heat engines for charged black holes in massive gravity for spherical (k = 1), flat (k = 0) and hyperbolic (k = −1) topologies. Although, η

k
is in general higher (lower) for hyperbolic (spherical) topology, we show that this order can be reversed in critical heat engines with efficiency higher for spherical topology, following in particular the order: η
−1 < η
0 < η
+1. Furthermore, the study of the near horizon region of the critical hole shows that, apart from the known q → ∞ condition, additional scalings of massive gravity parameters, based on the topology of the geometry are required, to reveal the presence of a fully decoupled Rindler space-time with vanishing cosmological constant.
Projected Newton method for noise constrained ℓ

p
regularization
Authors: Cornelis J , Vanroose W
Published: August 2020

Choosing an appropriate regularization term is necessary to obtain a meaningful solution to an ill-posed linear inverse problem contaminated with measurement errors or noise. The ℓ

p
norm covers a wide range of choices for the regularization term since its behavior critically depends on the choice of p and since it can easily be combined with a suitable regularization matrix. We develop an efficient algorithm that simultaneously determines the regularization parameter and corresponding ℓ

p
regularized solution such that the discrepancy principle is satisfied. We project the problem on a low-dimensional generalized Krylov subspace and compute the Newton direction for this much smaller problem. We illustrate some interesting properties of the algorithm and compare its performance with other state-of-the-art approaches using a number of numerical experiments, with a special focus of the sparsity inducing ℓ
1 norm and edge-preserving total variation regularization.
Chemical pressure induced near-complete suppression of spin-wave excitations in Bi0.9A0.1FeO2.95 (A = Ba, Ca)
Authors: Das B K , Sairam T N , Ramachandran B , Ramachandra Rao M S
Published: August 2020

We have probed the changes in the phonon and magnon modes of BiFeO3 on substitution of Ba and Ca at the A-site using infrared reflectance spectroscopy. The systematic hardening of the phonon modes in the doped samples is seen to correlate well with the volume reduction of the unit cell observed from the Rietveld measurements. This is attributed to the generation of chemical pressure in these samples on account of substitution of the dopants. In addition, a near-complete suppression accompanied by a complete lifting of the degeneracy of the magnon modes as compared to the pristine BiFeO3 is detected for the Ca-doped samples. These results suggest that aliovalent doping at A-site affects the crystal field of FeO6 octahedra of BiFeO3, which eventually modifies its magnetic nature. These doping-induced modifications are mainly responsible for the improved magnetic and magnetoelectric properties of the Ca-doped BiFeO3 samples.
Excitation and propagation of spin waves in non-uniformly magnetized waveguides
Authors: Vanderveken Frederic , Ahmad Hasnain , Heyns Marc , Sorée Bart , Adelmann Christoph , Ciubotaru Florin
Published: August 2020

The characteristics of spin waves in ferromagnetic waveguides with non-uniform magnetization have been investigated for situations where the shape anisotropy field of the waveguide is comparable to the external bias field. Spin-wave generation was realized by the magnetoelastic effect by applying normal and shear strain components, as well as by the Oersted field emitted by an inductive antenna. The magnetoelastic excitation field has a non-uniform profile over the width of the waveguide because of the non-uniform magnetization orientation, whereas the Oersted field remains uniform. Using micromagnetic simulations, we indicate that both types of excitation fields generate quantised width modes with both odd and even mode numbers as well as tilted phase fronts. We demonstrate that these effects originate from the average magnetization orientation with respect to the main axes of the magnetic waveguide. Furthermore, it is indicated that the excitation efficiency of the second-order mode generally surpasses that of the first-order mode due to their symmetry. The relative intensity of the excited modes can be controlled by the strain state as well as by tuning the dimensions of the excitation area. Finally, we demonstrate that the nonreciprocity of spin-wave radiation due to the chirality of an Oersted field generated by an inductive antenna is absent for magnetoelastic spin-wave excitation.
The benefit of high-performance gradients on echo planar imaging for BOLD-based resting-state functional MRI
Authors: Kang Daehun , Jo Hang Joon , In Myung-Ho , Yarach Uten , Meyer Nolan K , Bardwell Speltz Lydia J , Gray Erin M , Trzasko Joshua D , Huston III John , Bernstein Matt A , Shu Yunhong
Published: August 2020

Improved gradient performance in an MRI system reduces distortion in echo planar imaging (EPI), which has been a key imaging method for functional studies. A lightweight, low-cryogen compact 3T MRI scanner (C3T) is capable of achieving 80 mT m−1 gradient amplitude with 700 T m−1 s−1 slew rate, in comparison with a conventional whole-body 3T MRI scanner (WB3T, 50 mT m−1 with 200 T m−1 s−1). We investigated benefits of the high-performance gradients in a high-spatial-resolution (1.5 mm isotropic) functional MRI study. Reduced echo spacing in the EPI pulse sequence inherently leads to less severe geometric distortion, which provided higher accuracy than with WB3T for registration between EPI and anatomical images. The cortical coverage of C3T datasets was improved by more accurate signal depiction (i.e. less dropout or pile-up). Resting-state functional analysis results showed that greater magnitude and extent in functional connectivity (FC) for the C3T than the WB3T when the selected seed region is susceptible to distortions, while the FC matrix for well-known brain networks showed little difference between the two scanners. This shows that the improved quality in EPI is particularly valuable for studying certain brain regions typically obscured by severe distortion.
Self-organized multicellular structures from simple cell signaling: a computational model
Authors: Mulberry Nicola , Edelstein-Keshet Leah
Published: August 2020

Recent synthetic biology experiments reveal that signaling modules designed to target cell–cell adhesion enable self-organization of multicellular structures Toda et al (2018 Science
361 156–162). Changes in homotypic adhesion that arise through contact-dependent signaling networks result in sorting of an aggregate into two- or three-layered structures. Here we investigate the formation, maintenance, and robustness of such self-organization in the context of a computational model. To do so, we use an established model for Notch/ligand signaling within cells to set up differential E-cadherin expression. This signaling model is integrated with the cellular Potts model to track state changes, adhesion, and cell sorting in a group of cells. The resulting multicellular structures are in accordance with those observed in the experimental reference. In addition to reproducing these experimental results, we track the dynamics of the evolving structures and cell states to understand how such morphologies are dynamically maintained. This appears to be an important developmental principle that was not emphasized in previous models. Our computational model facilitates more detailed understanding of the link between intra- and intercellular signaling, spatio-temporal rearrangement, and emergent behavior at the scale of hundred(s) of cells.
Numerical study of the effective modulus of elasticity of three-dimensional mechanical metamaterial
Authors: Akhmetshin L R
Published: August 2020

Metamaterials are of great interest due to their unusual properties and promising practical application. The paper studies a mechanical metamaterial bar composed of 81 unit cells. The unit cell is shaped to a cube the faces of which consist of two-dimensional tetrachiral elements. The elastic deformation of a metamaterial specimen is numerically modeled in uniaxial loading. How the twist angle and Young modulus of the metamaterial specimen depend on the parameters of the chiral structure is demonstrated. Value ranges of the parameters in which the twist angle is largely affected are found. Cell parameters that have the greatest and least influence on the metamaterial twist angle and Young’s modulus are determined. The effective Young’s modulus decreases by a factor of approx. 20 when changing the inner radius of the ring. An almost constant effective Young’s modulus is found.
Structure formation features of large block-shaped samples from the copper and aluminum alloy produced by the wire-feed electron-beam additive technology
Authors: Knyazhev E O , Panfilov A O , Kalashnikova T A , Kalashnikov K N , Gusarova A V , Chumaevskii A V
Published: August 2020

In this work the study of the structure of samples made by the wire-feed electron-beam 3D printing from copper C11000 and aluminum alloy AA5056 was carried out. The presence of a dendritic structure typical of this method was revealed, as well as the presence of pores, cracks and other defects that occurred during printing. Mechanical properties of samples cut in the planar section are at a rather low level. The ultimate tensile strength of copper block samples varies between 165 and 187 MPa. The relative elongation of samples without pores is at 18%, but with the presence of pores it decreases sharply to 7%, while the strength is practically not decreased. The samples of alloy AA5056 demonstrate slightly higher mechanical properties: the strength is at the level of 190-192 MPa and the relative elongation is about 16-18%. In samples with defects such as large pores or discontinuities, the strength drops to almost zero.
Computational modeling of boric acid droplet entrainment during water-water energetic reactor operation in emergency boiling mode
Authors: Sahipgareev A R , Shlepkin A S , Soshkina A S , Morozov A V
Published: August 2020

The results of a computational modeling of the processes of droplet entrainment of boric acid by a vapor stream in the event of an emergency at a water-water energetic reactor (WWER) nuclear power plant associated with a guillotine rupture of the main circulation pipeline and the loss of all alternating current sources are presented in the article. The dependence received in the course of computational modeling makes it possible to estimate the maximum size of the droplets carried away by the steam stream during the emergency process in the WWER reactor unit during the operation of the complex of passive safety systems in the pressure range 0.2-0.5 MPa. It was established that to the end of 72 hours of an accident the maximum size of droplets carried away from reactor is 0.11 mm.
Evaluation of elastic modulus of carbon fiber reinforced polymers using an optical extensometer
Authors: Lyubutin P S , Burkov M V , Eremin A V
Published: August 2020

The paper presents the results of application of different techniques for processing of digital image correlation data. The algorithms are described and applied for determination of elasticity modulus of carbon fiber reinforced polymer specimens tested by uniaxial tension. Two ways of evaluation of elongation along with two methods of elastic modulus calculation resulted in four techniques which have shown quite similar results with a scatter of 0.5-2%.
Study of the Stability of the Gallium-Containing Catalyst in the course of Conversion of Gaseous C1-C6 Hydrocarbons into Aromatic Compounds
Authors: Vosmerikov A V , Barbashin Ya E , Vosmerikova L N , Vagin A I
Published: August 2020

A study was made on the duration of the single-pass lifespan of the gallium-containing catalyst in the course of conversion of a model mixture of C1-C6 hydrocarbons into aromatic compounds. Using temperature-programmed desorption of ammonia, it has been found that some acid sites of the catalyst were irreversibly deactivated as a result of the reaction and oxidative regeneration. It has been shown that the gallium-containing catalyst characterized by high activity and stability in the course of aromatization of lower alkanes was able to withstand a certain number of reaction-regeneration cycles without reducing its activity.
Chemical codes identification based on periodic dependences of chemical element distribution in biological objects
Authors: Otmakhov V I , Kuskova I S , Obukhova A V , Petrova E V , Sarkisov Yu S
Published: August 2020

This work for the first time considers the periodic dependences of logarithm of chemical element concentration in human hair, animal hair, crude drugs and other objects of flora and fauna of Siberia on the atomic number in the periodic table. The hypothesis is put forward that the maxima on the constructed curves can serve as the original code reflecting their interrelation with various factors of a genetic and ecological nature. The samples of the animal origin, blood-sucking insects and fish are selected in Siberia (the Tomsk region), whereas the samples of the drug plants are taken in the Krasnoyarsk region. The diversity of the objects at issue and the regions for sampling is conditioned by the breadth of challenges this paper faces. The chemical element concentration in the objects is determined by the detection limit of the method applied (from 1· 10–5 to 104 µg/g and more). For convenience, this element concentration is represented as logarithmic charts. It is shown that periodic dependences of the living world of Siberia and Siberian regions are of the same genetic nature. In this research performed in the certified Environmental Monitoring Laboratory of the Tomsk Regional Core Facility Center of National Research Tomsk State University we use the Spectrometer “Grand” with a multichannel analyzer of emission spectra.
Design of SiO2 materials with hierarchical structure as promising supports for catalysts
Authors: Zubkov A V , Vyshegorodtseva E V , Bugrova T A , Mamontov G V
Published: August 2020

The silicate support with a hierarchical structure based on diatomite and MCM-41 is synthesized. The MCM-41 is formed directly on the surface of diatomite and from the diatomite itself without the use of additional silica precursors. The structure of the synthesized samples is characterized by the low-temperature nitrogen adsorption and scanning electron microscopy (SEM). It was shown that hydrothermal treatment of diatomite with NaOH and cetyltrimethylammonia bromide leads to the partial dissolving of diatomite with self-assembly of MCM-41 fragments inside diatomite pores. The developed approach has demonstrated the opportunity to obtain the supports based on diatomite and MCM-41 that are characterized by a hierarchical structure (macropores of diatomite with size of 10-500 nm and mesopores of MCM-41 with size of 3-4 nm) and a high specific surface area that is promising for their application as supports for catalysts.
Laboratory study of the oil displacing ability of a chemical acid oil-displacing composition
Authors: Sholidodov M R , Altunina L K , Kozlov V V , Chernova U V
Published: August 2020

The paper presents the results of laboratory experiments to study the filtration characteristics of models of a heterogeneous reservoir of a Permian-carbon deposit in the Usinsk mine and the oil-displacing ability of a chemical acid oil displacing composition (AODC). The experiments were carried out on a setup for studying the filtration characteristics of heterogeneous reservoir models. The study found that the use of AODC will lead to a significant increase in the coefficient of oil-displacement.
Effect of bismuth ion implantation on the crystallization temperature of the amorphous Ge2Sb2Te5 thin films
Authors: Lazarenko P , Kozyukhin S , Sherchenkov A , Yakubov A , Zaytseva Yu , Dronova D , Boytsova O , Chigirinsky Yu , Zabolotskaya A , Kozik V
Published: August 2020

Bismuth doped Ge2Sb2Te5 thin films were prepared by magnetron sputtering of Ge2Sb2Te5 target with following ion implantation of Bi. Thin film compositions and elemental distribution across the film thicknesses were determined. An amorphous state of the as-deposited undoped and Bi-doped Ge2Sb2Te5 thin films was confirmed by X-ray diffraction. Temperature dependencies of the resistivity for Bi-doped Ge2Sb2Te5 thin films were measured. Two resistivity drops due to the crystallization and transformation from the cubic to hexagonal structure were determined. Decreases of the onset temperatures for the first and second transitions from 169.3 to 120.3 °C and from 188.0 to 153.0 °C with the increase of Bi concentration were found. It was shown, that the resistivity of the amorphous films sufficiently decreases with Bi concentration, while the variation of resistivity for the crystallized state is much smaller.
Modelling of sand cement hydration in normal conditions
Authors: Abzaev Yu A , Gnyrya A I , Korobkov S V
Published: August 2020

The paper considers the hardening mechanisms of the sand cement composition (0.75 sand and 0.25 Portland cement) during 28 days. In this study, the VCCTL tool is used for computer modelling of the sand cement hardening process. It is found that after 28 days, the sand cement hydration is ∼0.75, the porosity is over 0.20 and 0.32 at the water-cement ratio of 0.40 and higher, respectively. Calcium silicate hydrate (C–S–H) and portlandite (CH) are the main hydration products of Portland cement and responsible for the sand cement strength. Owing to the high porosity of sand cement, free moisture is present in it in large quantities. It is shown that the effective elastic moduli of sand cement rapidly grow during 200 hours and then monotonically lower. The yield stress monotonically grows during sand cement curing, and at 0.40 and 0.44 water-cement ratios achieves the maximum value. This growth thus depends on the water-cement ratio and affects Young’s modulus during the curing process. At the qualitative level, a correlation is observed between the yield stress and Young’s modulus depending on the curing time of sand cement with the discussed water-cement ratios.
The deformation characteristics of the modified heat-insulating foam concrete
Authors: Steshenko A B , Latypov A D , Ryabtseva N E
Published: August 2020

The present paper investigates deformation characteristics of natural hardened cement based foam concrete with chrysotile asbestos fibers and crystalline glyoxal. The given study is relevant as new methods for managing volumetric changes during the porous cement compositions operation are required to be developed. These new methods should allow obtaining high-quality, energy-efficient wall structures for application on the territory of the Russian Federation. Chrysotile asbestos fibers and crystalline glyoxal applied within the technology of cement foam concrete of natural hardening contribute to ensuring the increased deformation characteristics of concrete at the age of 28 days. The optimal compositions of heat-insulating foam concrete with the elastic modulus of 1035-1383 MPa, Poisson’s ratio of 0.1127-0.1446 and shear modulus of 465-604 MPa have been developed. The elaborated composition and technology of foam concrete production with glyoxal-containing additives is intended for use in the wall structures as well in monolithic construction as in pre-cast production.
Inhibition of tumor cell proliferation in vitro using atmospheric-pressure plasma jet
Authors: Evtina A A , Nekhoroshev V O , Buldakov M A , Cherdyntseva N V , Landl N V , Korolev Y D
Published: August 2020

The effect of atmospheric-pressure plasma jet on the proliferative activity of tumor and normal cells was studied. It was shown that under certain parameters, plasma jet inhibits the proliferative activity of tumor cells up to 75%. However, the reaction of normal cells under the same parameters of plasma exposure is different. It was found that low-temperature plasma jet stimulates the proliferative activity of normal cells up to 25% on the 5th day after exposure. The obtained data indicate the prospects of using this low-temperature plasma jet in biomedical research aimed to minimizing the negative impact on healthy tissues during antitumor therapy.
Software implementation for transfer functions of arbitrary order on managing controllers
Authors: Alekperli F A , Bayramova I S
Published: August 2020

Despite the great capabilities of controllers of the Simatic type, their library lacks a block for implementing the transfer functions necessary for programming complex control algorithms both in research by simulation and in industrial applications. This article discusses a method for software implementation of transfer functions of arbitrary order and delay in the Tİ A (Totally Integrated Automation) environment. The programs compiled in SCL and LAD languages and examples confirming the validity of the proposed method are given A program is presented that implements the solution of a difference equation in the SCL language, as well as programs for implementing the factorial and the number of combinations. These programs are designed as functions. The fourth program, compiled in the LAD language, is designed to build a transient process for a given transfer function in real time. The created software blocks allow developing software for the study of fairly complex regulatory systems by simulating and adapting to real industrial conditions without much difficulty.
Optimization of the algorithm for identifying digital traces of schoolchildren in the Altai Territory
Authors: Zhuravleva V V , Manicheva A S , Feshchenko A V , Berestov A V
Published: August 2020

The use of digital traces of social networks users has gained great popularity in various studies with the development of methods for analyzing big data. When processing data from social networks users, the problem of the incompleteness of the provided information arises (age, educational institution, year of admission/graduation are not specified). Users with such gaps do not fall into the field of view of the university as a result the number of potential applicants is significantly reduced. The aim of the project is to develop an algorithm for restoring information in a digital trace of a social networks user and its application to identify the group affiliation of schoolchildren whose digital trace contains incomplete information on the grade and place of study. The study was carried out on the data of schoolchildren from “The VKontakte” social network, corresponding to the ninth and eleventh grades, which were divided into four groups. The analysis of unique community subscriptions revealed significant differences in the age groups of schoolchildren. Then, based on gradient boosting, the algorithm that allows restoring missing information in the digital trace of schoolchildren was built. The optimization of the parameters of this algorithm based on numerical experiments allowed obtaining the precision of the order 0.6. The algorithm was used to identify groups of schoolchildren in 9th and 11th grades, in the digital trace of which there was incomplete information. The practical significance of the project is to expand the target audience of future university applicants and, as a result, the opportunity for the university to help them using career guidance measures in social networks to choose an educational program more consciously.
Optical incoherent direction finder as a part of a fault-tolerant complex for landing onto small bodies of the Solar System
Authors: Lobanov A A , Alpatov A N , Mozharov G A , Torshina I P , Troitsky V I
Published: August 2020

The subject of the study is the on-board guidance and navigation system for an autonomous landing of a space probe. The list of on-board equipment for safe landing of the spacecraft on the small bodies of the solar system (SBSS) is offered. The algorithm is proposed to combine all the on-board equipment into a single fault tolerance system. All the equipment is selected under the condition of the ability to identify failures at an early stage. The novelty of the method is in diversifying methods that are used in each stage of failure analysis. Such general method allows rejecting the results of some failure measurements from the further process thus preventing possible accident. The algorithm suggests two-stage control of the on-board systems that allows improving the fault tolerance. The first stage is based on the method of analysis of a number of double unequal measurements, but unlike the classical approach, it is assumed not to improve accuracy, but to search for errors. The second stage is based on the analysis of the parameters to control the internal equipment in order to predict failures.
Design of Border Security Defense System for VPN Network in Power Enterprises
Authors: WenZhen Ma , MingChang Xu
Published: August 2020

In order to ensure the safe and stable operation of the power system, the VPN network border security defense system of power enterprises is designed. The hardware of the system is planned and designed, including cooperative intrusion detection, security audit, cooperative camouflage, collaborative firewall, disaster recovery and electronic forensics. On the basis of the hardware design, the network data in the gateway is detected by using the cooperative control framework and other security technologies, and the attack behavior is analyzed by using host based intrusion detection, and the network information security situation assessment based on si-s0 is proposed. The algorithm estimates the security state of network intrusion information and realizes the security defense of network boundary. The experimental results show that the designed VPN border security defense system has higher security than the traditional system, and fully meets the research requirements.
Application of intelligent control in industrial process control automation
Authors: Hong Wang , YanYing Li
Published: August 2020

Based on the development background of industrial 4, the development status of industrial process control automation is analyzed, and the application of intelligent control is discussed. First, combined with the forefront of industrial process automation development, the current hot point intelligent control technology and means are summarized. Secondly, the specific application of intelligent control is discussed. Finally, the application development suggestions of intelligent control are put forward. The application of intelligent control has played an important driving role. Combined with the specific application and research, we summarized the application of intelligent control and shared it with the relevant personnel for reference.

From the point of view of the research on and application of industrial process control automation, the key is to realize intelligent production, the key is to realize the intellectualization of manufacturing process, and then to achieve the goal of high efficiency and green development, and to build an industrial manufacturing mode that can realize intelligent decision making and intelligent independent control of manufacturing equipment. It is necessary to optimize the control of industrial process, that is to optimize and control the intelligence and integration, realize efficient perception of production conditions change, adaptive decision-making, and track the setting value of control system to achieve the optimal target of operation index, that is, to improve the quality and efficiency of production, to reduce energy consumption and to promote the continuous development of industry. The following analysis is carried out.
Research on Network Information Security Issues and Strategies under the Internet Plus Environment
Authors: Li E
Published: August 2020

In today’s world, with the rapid development of science and information technology, the internet has become an indispensable medium in people’s daily life. Through the internet, we can carry out various activities very conveniently and save a lot of manpower and material resources. In recent years, internet plus has become a hot word. It aims to deeply integrate the internet with traditional industries and create new development ecology with the help of internet platform and network information technology. With the deepening of network information technology, network information security has become an increasingly prominent problem. This paper analyzes the network information security problems under the internet plus environment, and puts forward corresponding countermeasures to reduce the emergence of various network information security problems in order to maintain people’s information security.
Research on Fault Transmission Method of Switchgear Based on Internet of Things
Authors: Chen Jianxin , Yu Shujiang , Jiang Yijun , Wang Genming
Published: August 2020

In order to meet the intelligent function of the switchgear, the fault transmission method of the switchgear based on the Internet of Things is researched and designed. Firstly, use the data collection terminal and monitor to monitor the parameters in the switchgear and transmit the detected faults; Secondly, use the Internet of Things method to design a monitoring switch platform to provide an operating environment for fault monitoring; Finally, verify the accuracy of the IOT(internet of things) technology in the fault transmission of switchgear.
Research on comprehensive index of freezing disaster caused by rain and snow
Authors: Chang Zhenxing , Wei Zhen , Chen Tao , Wang Guanning , Ma Na , Zheng Huijie
Published: August 2020

In this study, the ISD surface meteorological observation data set in NCEI database website under NOAA is used. The longitude and latitude range of the selected stations is 105°E∼117.5°E, 24°N∼32.5°N. The basic meteorological data of the winter from 2001 to 2010 are statistically analyzed. The statistical analysis shows that there is a short period of severe cooling to below 0°C and relative humidity increasing in 2008, in addition, the observed wind speed did not change significantly, the wind direction changed disorderly, and the sea level pressure at different stations showed high consistency. Based on the statistical analysis, three basic meteorological elements, temperature, relative humidity and wind speed, are selected to normalize, and then the rain snow freezing disaster index is generated according to the weight. According to the unified standard, Guizhou Province is (0.65,0.3,0.05), Hunan and Jiangxi Province is (0.55,0.4,0.05). Through the qualitative evaluation of the weight factor scheme, it can reasonably reflect the situation of rain and snow freezing disaster.
Effects of Sidewall Inclination on Performance of Electrothermal Micro-Actuator
Authors: Teng Siru , Cai Chunhua
Published: August 2020

As an important part of Micro-Electro-Mechanical systems (MEMS), micro-actuators have a direct impact on the performance of MEMS devices. This paper presents the effects of sidewall inclination of deep reactive ion etching (DRIE) on the performance of U-shaped electrothermal micro-actuators. The electrothermal micro-actuator models with sidewall inclination angles from -5° to 5° are simulated through finite element method (FEM) by ANSYS to study the influences on the output displacement and the highest node temperature. The simulation results show that electrothermal micro-actuator with larger sidewall inclination angle has more displacement deviation. In addition, larger voltage amplifies the deviation of displacement. The highest node temperature decreases with the increase of the sidewall inclination, and the deviation is small.
Review of Modern Field Effect Transistor Technologies for Scaling
Authors: Zhang Shubo
Published: August 2020

This paper mainly reviews the field-effect transistor technology most involved in the modern electronics industry. Short channel effect promotes the continuous update of the field effect transistor structure. Therefore, the principle and influence of the short channel effect is first introduced. This paper focuses on the development history and current status of fin structure and gate-all-around field effect transistors, as well as their respective technical difficulties. By reviewing these two main technologies, the development process and technical difficulties of the technology are basically clarified. At the same time, the applications of these technologies in the enterprise are introduced. And finally, the future development trend of the technology is proposed.
A Novel Approach for Indoor Positioning Based on RFID and UWB
Authors: Huang Zhengang , Han Zheng , Li Heng , Wang Huadeng
Published: August 2020

In recent years, with the rapid development of mobile communication network, wireless network technology and pervasive computing, the demand of location-based service, especially indoor positioning, is becoming increasingly urgent. Indoor positioning based on Ultra wideband (UWB) is one of the most accurate indoor positioning technologies; however, due to its high cost, it is difficult to cover the large indoor environment completely. In view of the limitations of the existing indoor positioning technology, this paper designs and implements an indoor positioning algorithm and prototype system based on RFID, which could assist the existing indoor positioning based on UWB and reduce costs on the premise of positioning. Experiments show that the algorithm in this paper has better effect than other methods.
Dual time-scale co-estimation of state-of-charge and state-of-health for lithium-ion battery pack with passive balance control over whole lifespan based on particle filter
Authors: Li Zhe , Ma Chenhui , Deng Bo , Ou Yang , Wang Yi , Meng Zaiqiang , Wang Peng , Fan Jie
Published: August 2020

Battery management system (BMS), as the key component in electric vehicles (EVs), takes the responsibility of sate-monitoring and safety-protection for the battery pack. State of charge (SOC) and state of health (SOH) are highly correlated with the safe and efficient operation of EVs, thus BMS must realize accurate estimation of them. This paper presents a combined SOC and SOH estimation for lithium-ion battery pack with passive balance control over the battery’s cycle lifespan. Considering the slow variation of SOH and fast variation of SOC, a dual time scale combined SOC and SOH estimation method is proposed. The battery cell with minimum capacity is located offline and then SOC is estimated and updated online, which lightens the computational burden for BMS on EVs. Results show that the proposed method can realize accurate SOC and SOH estimation. The SOH estimation error can be beneath 3% and the SOC estimation accuracy can improve 7%.
Savitzky-Golay Filtering and Improved Energy Entropy for Speech Endpoint Detection under Low SNR
Authors: Gan Zhenye , Hou Miaomiao , Hou Hexiang , Yang Hongwu
Published: August 2020

Under the condition of low signal-to-noise ratio (SNR) or non-stationary noise, the performance of endpoint detection is poor. Therefore, this paper proposes a speech endpoint detection algorithm for low SNR. In this paper, Savitzky-Golay filtering, improved sub-band energy entropy and constant Q-transform (CQT) are used to extract features, and single parameter double threshold method is used to realize endpoint detection. In this paper, clean speech and noise-92 speech fragments are used to evaluate the algorithm. Experimental results show that the algorithm in this paper can distinguish speech endpoints well. For Gaussian white noise, Factory noise and Volvo noise, the detection accuracy of the improved algorithm is improved by 5.5%, 5.3% and 4.6% respectively. Therefore, the algorithm in this paper can separate the mute and voice in complex environment.
Study on the Role and Approach of Culture Background Knowledge Dissemination Based on Information Technology Application
Authors: Wang Weifeng
Published: August 2020

In English teaching, it should be attached great importance to the infiltration of Culture Background Knowledge. Teachers should provide students with Culture Background Knowledge by means of information technology. Starting from the teaching practice, this paper explores the conjunction of information technology and culture background knowledge teaching, and discusses how to infiltrate English Culture Background Knowledge in information technology teaching from multiple perspectives.
Phaseless signal recovery from triple-window short-time Fourier measurements
Authors: Lin Wei , Zhang Ruiqiong , Xu Xinlan , Min Hao
Published: August 2020

In this paper, we present a signal recovering algorithm from the magnitudes of its short-time Fourier transform when triple window functions are utilized. Some sufficient conditions are proved on the window functions under which the magnitude of the signal vector can be recovered and the phases of the rest of coordinates can be propagated. Finally, we propose an example to show that the signal vector, up to a unimodular, can be recovered from the magnitudes of its triple-window short-time Fourier transforms.