bluuebunny/crossref_metadata_2025 huggingface dataset:
Epistaxis: was kann zum Tode führen?
Authors: Hohenhorst Winfried
Published: July 2019

Integrate (The National ENT Trainee Research Network). Epistaxis and mortality. J
Laryngol Otol 2018; 132: 1061–1066

Die Epistaxis ist einer der häufigsten ORL-Notfälle. In dem Programm:
„Epistaxis 2016: National Audit of Management“ wurden prospektive Daten über
30 Tage zur standardisierten Versorgung einer Epistaxis durch die britische
Gesellschaft für Otorhinolaryngologie gesammelt. Dabei wurde eine 30-tägige
Gesamtmortalität von 3,4 % festgestellt. In einer Studie wurden Patienten,
die während des Auditzeitraums verstarben, genauer untersucht.
Ingwer und Novafen gleichwertig bei Menstruationsschmerz
Authors: Uehleke Bernhard
Published: July 2019

In diese Studie aus dem Iran wurden 168 Studentinnen im offiziellen Single-Status im Alter zwischen 18 und 26  mit primärem Menstruationsschmerz eingeschlossen. Dem Abstrakt nach wurde die Schmerzintensität in beiden Gruppen nach der Behandlung deutlich gesenkt – von rund 7 auf 3 Stufen einer visuellen Analogskala (VAS).
Blood Flow Restriction Alters Motor Unit Behavior During Resistance Exercise
Authors: Fatela Pedro , Mendonca Goncalo V. , Veloso António Prieto , Avela Janne , Mil-Homens Pedro
Published: July 2019

We aimed to determine whether blood flow restriction (BFR) alters the characteristics of individual motor units during low-intensity (LI) exercise. Eight men (26.0±3.8 yrs) performed 5 sets of 15 knee extensions at 20% of one-repetition maximum (with and without BFR). Maximal isometric voluntary contractions (MVC) were performed before and after exercise to quantify force decrement. Submaximal isometric voluntary contractions were additionally performed for 18 s, matching trapezoidal target-force trajectories at 40% pre-MVC. EMG activity was recorded from the vastus lateralis muscle. Then, signals were decomposed to extract motor unit recruitment threshold, firing rates and action potential amplitudes (MUAP). Force decrement was only seen after LI BFR exercise (–20.5%; p<0.05). LI BFR exercise also induced greater decrements in the linear slope coefficient of the regression lines between motor unit recruitment threshold and firing rate (BFR: –165.1±120.4 vs. non-BFR: –44.4±33.1%, p<0.05). Finally, there was a notable shift towards higher values of firing rate and MUAP amplitude post-LI BFR exercise. Taken together, our data indicate that LI BFR exercise increases the activity of motor units with higher MUAP amplitude. They also indicate that motor units with similar MUAP amplitudes become activated at higher firing rates post-LI BFR exercise.
Preanalytical Variables in Coagulation Testing: Setting the Stage for Accurate Results
Authors: Gosselin Robert C. , Marlar Richard A.
Published: July 2019

Many preanalytical variables may affect the results of routine coagulation assays. While advances in laboratory instrumentation have partially addressed the laboratory's ability to recognize some of these variables, there remains an increased reliance on laboratory personnel to recognize the three potential areas where coagulation testing preanalytical issues may arise: (1) specimen collection (including patient selection), (2) specimen transportation and stability, and (3) specimen processing and storage. The purpose of this article is to identify the preanalytical variables associated with coagulation-related testing and provide laboratory practice recommendations in an effort to improve the quality of coagulation testing and accuracy of result reporting.
Simultaneous detection of electrically detected magnetic resonance and electron spin resonance using composite modulation
Authors: Suzuki Takayuki
Published: July 2019

Studies on the behavior of electron spins in the working states of organic and inorganic semiconductor devices are extremely important for understanding the mechanisms that cause the degradation of devices. Electrically detected magnetic resonance (EDMR) and electron spin resonance (ESR) spectroscopies are considered as effective and complementary methods in such studies. However, conventional attempts to monitor both types of spectra in real time have limitations owing to throughput performance and measurement optimization. To overcome these limitations, we present a composite modulation scheme, which applies microwave and magnetic field signals as a simultaneous detection method. The main principle is to use a periodic arbitrarily shaped microwave pulse and to burst a magnetic modulation signal in the latter half period when the microwave pulse is not applied. This scheme aids in measuring EDMR and ESR spectra simultaneously and tuning the measurement parameters of each spectrum independently. Furthermore, it becomes possible to estimate the number and g values of spins, which contribute to the recombination current from the correction by the ESR spectrum of standard samples. This method is expected to be a useful spectroscopic method for future studies on spintronics.
Observation of phase dependent voltage signals in microwave spin pumping experiments
Authors: Chaudhuri Ushnish , Mahendiran R. , Adeyeye Adekunle O.
Published: July 2019

Microwave excitation of magnetization dynamics in a ferromagnetic material (FM)-normal metal (NM) interface induces spin currents into the NM via spin pumping. A symmetric DC voltage is often observed due to the inverse spin Hall Effect (ISHE). Apart from DC-ISHE, spin rectification (SR) effects due to microwave excitations also produce a DC voltage response. The voltage signals are sensitive to the phase difference between the electric and magnetic fields inside a FM. In this work, we investigate the effect of the microwave signal direction on the measurement of DC voltage signals by exciting radio frequency signals along two opposite paths using a vector network analyzer. We observe two distinct DC voltages at constant magnetic fields, over a wide range of microwave frequencies and powers. At resonance fields, these two voltage states are many microvolts apart, opening up a new possibility for using SR and spin pumping for spintronic devices.
Flexible patches for mm-wave holography
Authors: Burch J. , Ma J. , Hunter R. I. , Schulz S. A. , Robertson D. A. , Smith G. M. , Wang J. , Di Falco A.
Published: July 2019

In this work, we demonstrate, in simulation and experiment, reflection metasurface holograms operating in the millimeter wavelength range. Flexible holographic metasurface patches are the ideal platform to retrofit existing millimeter wavelength equipment to enhance and extend their functionality, e.g., for antennas and electromagnetic shielding. We present both a rigid and flexible implementation of the holographic metasurfaces, where the meta-atom is based on a three-layered structure with a gold c-ring as the polarization conversion element.
The dependence of breakdown field upon breakdown delay time in adiabatically compressed ferroelectric ceramics
Authors: Shkuratov Sergey I. , Baird Jason , Antipov Vladimir G. , Chase Jay B.
Published: July 2019

The ability of ferroelectric materials to generate high voltage under mechanical stress is widely used in transducer applications. The high strain-rate adiabatic compression of poled ferroelectrics results in their complete depolarization, the release of surface charges, and the generation of up to hundreds of kilovolts of electric potential that is an order of magnitude higher than in the low-strain piezoelectric mode. Electric breakdown within adiabatically compressed ferroelectric specimens is one of the factors that affect the generation of a high voltage by ferroelectric materials under extreme stress. We report herein the results of experimental investigations of the generation of high voltages by PbZr0.95Ti0.05O3 doped 2% Nb and PbZr0.52Ti0.48O3 doped 1% Nb2O5 poled ferroelectric ceramics adiabatically compressed by explosive-driven shock waves in a direction perpendicular to the direction of polarization. An important finding is the dependence of the ferroelectric breakdown field, Ebreak, upon breakdown delay time, td, for the two ferroelectrics, which is described by a power law: Ebreak(td) = β × td−η. This law can be used to characterize electric breakdown in adiabatically compressed ferroelectrics, for the prediction of voltage generated by ferroelectric materials under high strain rate loading, and for optimization of the ferroelectric materials properties for ultrahigh-power applications. The parameters of the power law indicate the possibility of an impulse thermal constituent in the mechanism for electric breakdown of adiabatically compressed ferroelectric ceramics. The Ebreak(td) relationships obtained in this study are important for theoretical consideration of mechanisms of breakdown in adiabatically compressed ferroelectrics and for ultrahigh-power applications of ferroelectric materials.
Electron reflectometry for measuring nanostructures on opaque substrates
Authors: Friedman Lawrence H. , Wu Wen-Li
Published: July 2019

Here, we present a method for measuring dimensions of nanostructures using specular reflection of electrons from an electronically opaque surface. Development of this method has been motivated by measurement needs of the semiconductor industry [International Technology Roadmap for Semiconductors 2.0. Metrology (http://www.itrs2.net, accessed 5 January 2017, 2015); Vaid et al., J. Micro/Nanolithogr., MEMS, MOEMS 13, 041410 (2014); Bunday, Proc. SPIE 9778, 97780E–97780E-34 (2016); Bunday et al., Proc. SPIE 10585, 105850I (2018)], and it can also be more broadly applicable to any periodic, pseudoperiodic, or statistically stationary nanostructures or nanopatterns on an opaque substrate. In prior work [Friedman et al., Appl. Phys. Lett. 111, 123106 (2017); Wu et al., U.S. patent 9,390,888 (12 July 2016)], it was demonstrated through the presentation of proof of concept experiments and simulated examples that Reflective Small Angle Electron Scattering (RSAES) can meet certain dimensional metrology requirements of the semiconductor industry. In RSAES, an entire reflected scattering pattern is measured, with the scattered electrons being of primary interest. Later, in the process of further simulating RSAES, it was serendipitously discovered that dimensional measurements using reflected electrons might be greatly simplified by Electron Reflectometry (ER), whereby the intensity of the specularly reflected electron beam is measured and the scattered beams are ignored [Friedman and Wu, U.S. patent application 2019/0057834 A1 (21 February 2019)]. This innovation may allow faster and cheaper development and deployment or at the very least provide an alternate pathway to exploit the phenomenon of reflected electrons for the dimensional measurements. Here, we discuss how ER complements existing dimensional measurement techniques and show simulated applications with an emphasis on defect detection and linewidth measurements.
Corrigendum to: Decreased expression of DNA methyltransferases in the testes of patients with non-obstructive azoospermia leads to changes in global DNA methylation levels
Authors: Uysal Fatma , Akkoyunlu Gokhan , Ozturk Saffet
Published: July 2019

DNA methylation plays key roles in epigenetic regulation during mammalian spermatogenesis. DNA methyltransferases (DNMTs) function in de novo and maintenance methylation processes by adding a methyl group to the fifth carbon atom of the cytosine residues within cytosine–phosphate–guanine (CpG) and non-CpG dinucleotide sites. Azoospermia is one of the main causes of male infertility, and is classified as obstructive (OA) or non-obstructive (NOA) azoospermia based on histopathological characteristics. The molecular background of NOA is still largely unknown. DNA methylation performed by DNMTs is implicated in the transcriptional regulation of spermatogenesis-related genes. The aim of the present study was to evaluate the cellular localisation and expression levels of the DNMT1, DNMT3A and DNMT3B proteins, as well as global DNA methylation profiles in testicular biopsy samples obtained from men with various types of NOA, including hypospermatogenesis (hyposperm), round spermatid (RS) arrest, spermatocyte (SC) arrest and Sertoli cell-only (SCO) syndrome. In the testicular biopsy samples, DNMT1 expression and global DNA methylation levels decreased gradually from the hyposperm to SCO groups (PPP
Scaffolding student self-reflection in translator training
Authors: Pietrzak Paulina
Published: July 2019

This article advocates for structured self-reflection as a means to scaffold learning in translator training. Metacognitive activity in translator training requires students to actively regulate their own process of both translating and learning to become a translator. Therefore, the nature and typology of (self-)reflection is examined as are tools that offer students structured opportunities to analyze and evaluate their own learning. Given that additional (self-)reflection in the translation classroom requires trainers to alter their teaching methods, this article also examines how their role in training changes as a result of its inclusion. An exploratory study on translation students’ prospective and retrospective self-reflection is described with student perspectives on the same translation task compared. Student expectations prior to translation are examined both pre- and post-task, emphasizing what students and teachers learn from reflective practice.
Calibration of industrial platinum resistance thermometers in thermostats (-40 °C to 420 °C)
Authors: Constantin Bordianu , Marina Denisova , Ibraev Meirzhan , Baghirov Azer , Hodzic Nedzadeta , Çorman Alev
Published: July 2019

The COOMET.T-S2 comparison is a regional comparison in which the national metrological institutes of Moldova, Georgia, Kyrgyzstan, Kazakhstan, Azerbaijan, Bosnia and Herzegovina and Turkey participate.

Two standard platinum resistance thermometers (100 ohm), manufactured at VNIIM, was used as a transfer standards. National Metrology Institute (NMI) of Republic of Moldova is a pilot laboratory in this comparison.

The purpose of the comparisons is to verify equivalence between the participating laboratories in the calibration of industrial platinum resistance thermometers by direct comparison in the range from minus 40 °C to 420 °C. The comparison results are used to confirm the calibration and measurement capabilities in this range.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Is adsorbed water responsible for 2800-3000 cm−1 band in Raman spectrum of inorganic matter?
Authors: Redkov A , Melehin V , Zhurikhina V
Published: July 2019

In papers devoted to Raman spectra of SiO2-(H2O)x gel, stishovite, silver surface and gold particles on copper surface the band at 2800 – 3000 cm−1 was attributed to adsorbed water in spite of the essential shift of this band relatively to conventional water band at ∼3500 cm−1. This interpretation is controversial and it needs to be discussed. Measurements of Raman spectra of a glass slide with a fingerprint allowed another interpretation of this band because deposition of the fingerprint on the slide surface resulted in appearance of 2800 – 3000 cm−1 Raman band, and Raman mapping of the slide surface reproduced a microphotograph of the fingerprint. This allows relating of this band to traces of organic compounds at the surface of the studied samples.
Study of nanocarbon thin-film field-electron emitters by Raman spectroscopy
Authors: Osipov V S , Besedina N A , Gabdullin P G , Kvashenkina O E , Arhipov A V
Published: July 2019

Raman spectroscopy was used to study the features of the electron-phonon interaction in thin carbon films that are capable of low-field emission of electrons. It was found that in the Raman spectra of samples with this ability the characteristic peaks of carbon were almost completely suppressed, and also a wide photoluminescence band could be present. At the same time, the Raman spectra of non-emitting samples had the form typical of graphite-like carbon spectrum. This observation is in accordance with the two-barrier model of low-field electron emission from thin films of considered type, corresponding to which their emissive capability is maintained by the presence of hot electrons. Thus, in thin films consisting of numerous isolated carbon islands (nanoclusters) the extraction of electrons into the vacuum is facilitated by prolonged hot electron lifetime. Such prolongation, in turn, can be associated with the suppression of electron-phonon interactions by the spatial confinement effect. Consequently, it should result in the decrease of prominent bands in Raman spectra which are originated by electron-phonon interactions, while the photoluminescence intensity may, on the contrary, rise. Particularly such deformations of the Raman spectra were observed in the present study.
Acceptor and band states in quantum wells in multiband model
Authors: Vinnichenko M Ya , Makhov I S , Sofronov A N , Firsov D A , Vorobjev L E
Published: July 2019

We developed the framework for numerical calculation of the valence band dispersion in quantum well structures and the energy spectrum of the shallow acceptor in QWs. We used the finite-difference method to quantize the Luttinger-Kohn Hamiltonian and the decomposition of the impurity potential over the eigenstates of the Luttinger-Kohn Hamiltonian with the QW profile to obtain the acceptor states energies and wavefunction in

k
→

-space. Developed approach allows one to calculate the energies of the acceptor states with spherical symmetry for an arbitrary QW potential profile with the coordinate-dependent material parameters.
Using electrostatic energy analyzer of a plane of symmetry for recording field emission spectra from carbon nanotube array
Authors: Bondarenko V B , Davydov S N , Kniazkov A V , Filimonov A V
Published: July 2019

In this paper, the possibility is discussed of using electron emission spectroscopy to study low voltage field emission phenomenon. While using an electrostatic electron energy analyzer with the plane of symmetry, electron energy spectra were recorded with the energy resolution of ΔE ≈ 10-30 meV. The energy analysis has been done of the electrons emitted from the array of nanotubes produced by CVD method. The conclusion is that the low-voltage emission is local and that it is caused by very strong and inhomogeneous electron field produced by surface charged defects.
An investigation of the thermodynamic properties of molecular crystals by the differential scanning calorimetry
Authors: Borisov A K , Egorov V M , Marikhin V A
Published: July 2019

The thermodynamic properties of long-chain molecular crystals (LMC) have been investigated by using differential scanning calorimetry. The impact of the chain length and of the chain end group type on the thermodynamic characteristics of the first and second order phase transitions in LMC has been studied. A method of the analysis of the peak shape of the first order transitions based on the theory of diffused phase transitions has been developed. The method allows one to estimate the size of the new phase nuclei within the bulk of the former phase. To estimate a true peak shape of the first order phase transition, a method to separate the overlapped heat capacity peaks has been proposed for the first time. This new method takes into consideration the hysteresis effects.
A novel method of waste processing of polymetal raw materials to make useful nanoproducts
Authors: Natorkhin M I , Bobyl A V , Cheremisin A V , Sokolov M S
Published: July 2019

The article deals with the theoretical basis of polymetal waste processing in chloride solutions. A schematic diagram is proposed for the processing of polymetal raw materials in a closed cycle. According to this scheme, the possibility is shown of obtaining metal products with highly developed nanostructure.
Quantification of changes in cellular morphology during cell necrosis obtained from 3D refractive index distributions
Authors: Gorbenko D A , Belashov A V , Belyaeva T N , Kornilova E S , Semenova I V , Vasyutinskii O S
Published: July 2019

In this paper we perform an analysis of changes in cellular morphology in response to photodynamic treatment in vitro. Experiments were performed by means of digital holographic tomography. 3D spatial distributions of refractive index in cells were obtained and main morphological parameters of cells were determined: volume, average height, membrane area. The cellular response to treatment at different doses was studied and changes in morphology were correlated with major cell death pathways, apoptosis and necrosis. The necrosis pathway was studied in dynamics. The data obtained by holographic tomography were validated using a standard test for the integrity of cell membranes, conducted using a confocal fluorescent microscope.
Substituted (Nd,Pr)2Fe14B alloys: structural features and magnetic properties
Authors: Politova G A , Tereshina I S , Kaminskaya T P , Viryus A A , Paukov M A , Lukin A A , Andreev A V
Published: July 2019

In this work the magnetic properties of (Nd,Pr)2Fe14B alloys have been investigated in a wide range of temperatures (4.2 – 700 K) and magnetic fields (up to 14 T). The features of the structure were studied using two methods: SEM and AFM/MFM. Magnetic phase transition diagram was constructed. In the region of magnetic phase transitions (Curie and spin- reorientation transition temperatures) the value of the magnetocaloric effect was determined as an entropy change. The constancy of the magnetocaloric effect value for (Nd,Pr)2Fe14B alloys has been established.
Broadening of X-ray reflections and inhomogeneous strain distribution in PbZrO3/SrRuO3/SrTiO3 epitaxial heterostructures
Authors: Lityagin G A , Vakulenko A F , Gao R , Dasgupta A , Filimonov A V , Burkovsky R G
Published: July 2019

Antiferroelectric thin film heterostructures are important in energy storage technology and have prospective applications in domain wall nanoelectronics. The improvement of functional properties of this kind of material is directly connected with the effect of epitaxial strain. Thus, the investigations of strain distribution in the antiferroelectic films volume are on demand. In this work we have studied the distribution of orientational domain states and the condition of near-interface layer in a set of PbZrO3 films with different thickness grown on SrRuO3/SrTiO3 substrate. The analysis of X-ray diffraction curves shows that only the relatively narrow near-interface part of PbZrO3 film experiences significant strain along the normal to the surface, which decays very quickly on moving away from the interface. The out-of-plane strain profiles are strongly similar in films of different thickness above d=50 nm. The inhomogeneous out-of-plane strain is surprisingly of compressive character, which we attribute to the effects of hydrostatic-like compression associated with the presence of edge dislocations. In the films of higher thickness, we observe unusual broadening of the Bragg reflections, which is also tentatively associated with relaxation through the formation of dislocations.
Study of surface topography and emission properties of thin Mo and Zr films
Authors: Bizyaev I S , Gabdullin P G , Arkhipov A V , Babyuk V Ye
Published: July 2019

Thin films of Mo and Zr were deposited on Si wafers by the magnetron sputtering process with controlled parameters. Correlation between their field-emission properties and surface morphology was investigated. The study results were found to be in good agreement with previous data acquired for carbon nanocluster films, which witnesses that morphology can have greater effect on field emission capability of thin films than their chemical composition and work function.
Substrate modification influence on properties of nanocomposite based on TiO2 and gold nanoparticles
Authors: Mishin M V , Vorobyev A A , Kondrateva A S , Koroleva E Y , Karaseov P A , Bespalova P G , Shakhmin A L , Glukhovskoy A V , Wurz M C , Filimonov A V
Published: July 2019

In this work, we study photo-induced current transfer through nanocomposite structures consisting of the TiO2 coating activated with plasmonic gold nanoparticles on top of pillar-like structured SiO2. It is shown that the photo-response of the nanocomposite can be adjusted via tuning of the heterostructure topology. Processes at the interface between silicon and noble metal nanoparticle play an important role in charge carrier photo-generation. The high photo-activity in visible part of spectrum has been found in the composite, containing pillar-like silicon dioxide nanostructures [1]. The electron transport via the SiO2 layer from the potential well at the TiO2-SiO2 interface to the n-Si conduction band was explained by electron tunneling mechanism. We present the empirical qualitative model which explains experimental results and helps to separate the contributions of different transport mechanisms.
Label-free real time optical detection of binding of living cells and biopolymers
Authors: Morozova O V , Isaeva E I , Klinov D V
Published: July 2019

Biosensor based on long range surface waves on one-dimentional photonic crystal (PC) surface in microfluid channel was used to detect binding of cells, viruses, nanoparticles and proteins. Covalent attachment of biopolymers to polyaminated PC with glutaraldehyde cross-linking in microfluid channel results in functionally active proteins, living eukaryotic, bacterial cells and viruses. The evident advantages of the optical biosensor include native conformations of biopolymers, detection of reversible or permanent specific binding with ligands, broad detection scale from eukaryotic cells to low-molecular-weight ligands and observations in real time with possible calculations of affinity and kinetic constants. However, relatively low sensitivity limit near 0.1 μg/ml of proteins is significantly less those of ELISA and xMAP immunofluorescent analysis (approximately 1 pg/ml). Integral adlayer thickness does not reveal molecular events on each cell with possible variations. The label-free real-time optical detection allowed us to estimate cytotoxicity of currently used and novel drugs and to explore the antiviral properties of new compounds.
Terahertz spectrometer for express diagnosis of breast cancer
Authors: Taranets K B , Bagraev N T , Klyachkin L E , Malyarenko A M
Published: July 2019

We demonstrate a novel approach to the problem of express diagnostics based on THz spectral features of the breast cancer and THz emission and detection provided by the topological edge channels of silicon nanosandwichstructures.
Optical tomography of residual stresses in GRIN rod lenses with transverse and longitudinal translucence
Authors: Karov D , Puro A , Fadeev A , Kuzmina A
Published: July 2019

The residual stresses (RS) in gradient-index (GRIN) rod lens are formed due to the material characteristics gradient. RS can lead to the birefringence effect. If a GRIN lens is birefringent, its applications may be limited, because the anisotropy can cause the image quality degradation. According to this, the urgent task is to develop a non-destructive diagnostic method of RS in the gradient optical structures. This paper presents the relations of the generalized method of integral photoelasticity for reconstructions of RS (optical tomography of the stress field) for the case of the bending probing rays in GRIN optical rods with a radial distribution of the refractive index. The problem is solved with plane strain approximations. RS Distributions are given reconstructed from tomographic data obtained with transverse and longitudinal (coaxial) translucence of GRIN rod lens.
Analysis of intensity/time series obtained in homodyne evanescent wave DLS electrophoretic experiments
Authors: Savchenko E A , Skvortsov A N , Velichko E N , Madzhhinov A R , Nezhinskikh S S
Published: July 2019

The electrophoretic motion in monodisperse and polydisperse systems of silica microspheres was studied by evanescent wave dynamic light scattering technique with homodyne detection. Instead of the attempts to calculate average autocorrelation function, the intensity temporal profile was assessed by short-time Fourier transform was followed by multivariate curve resolution. The profile contained random alternate smooth regions and oscillating regions with definite frequencies. The effect was attributed to the few number of moving particles in the narrow zone, illuminated by evanescent wave. The changes in the short-time spectrum corresponded to entry or exit of individual particles. Feasibility to evaluate the mobility of individual particles in polydisperse systems is discussed.
Cooperative spontaneous decay of local excitation in a dense and disordered ensemble of point-like impurity atoms near a charged conductive surface
Authors: Kuraptsev A S
Published: July 2019

On the basis of the general quantum microscopic theory we study the process of spontaneous decay of an excited atom in a dense and disordered ensemble of point-like impurity atoms embedded into transparent dielectric and located near a charged perfectly conducting surface. We have analyzed the simultaneous influence of the modified spatial structure of field modes near the conductive surface and the electric field on the character of interatomic dipole-dipole interaction. This leads to the modification of the transition spectrum of an excited atom inside an ensemble and the spontaneous decay dynamics. We have shown that the electric field changes the cooperative Lamb shift, as well as the character of sub- and superradiant decay.
Modeling parameters of the flood control facilities adapted to climate change
Authors: Antonov V I , Badenko V L , Davydov R V , Maslikov V I , Molodtsov D V
Published: July 2019

The article analyzes the results of modeling the regulation of flood flow in a river basin by the flood control facility on a side tributary of the river under conditions of climatic changes. The use of geographic information system for assessing the impact of the flood control facilities on the environment when justifying their parameters is considered. The need to create anti-flood hydro systems on side tributaries exists because the water capacity of existing and projected hydro systems may not be enough to transform the flood in conditions of economic and climatic changes. The problem arises of determining the required water capacity of the flood control facility and its location considering environmental requirements.
A new approach to differential lung diagnosis with CT scans based on the Siamese neural network
Authors: Meldo A A , Utkin L V
Published: July 2019

A lot of computer-aided diagnosis systems for lung cancer detection have been developed in the last years, but most of them may be not effective when we deal with the differential diagnosis. Only a part of patients with lung cancer have a typical nodular cancer. Some patients have the extremely difficultly recognized lung cancer due to its atypical visualization. A new approach is proposed for differential lung diagnosis and for solving the problem of classifying all types of lung cancer. It is based on the following ideas. First, we apply the length chord and Hounsfield unit value histograms characterizing the inner structure of a tissue and its surrounding as a new feature representation of the tissue. Second, we collect a special dataset which contains a lot of atypical cases of cancer and non-cancer tissues. Third, we propose to use histograms as well as suspicious lung object images for training and using two Siamese neural networks which can be viewed as a key element of the proposed approach and allow us to implement some elements of explainable artificial intelligence systems.
Stress state analysis of a semi-infinite region with a hole by the combined method
Authors: Chernysheva N V , Melnikov B E
Published: July 2019

A computational algorithm based on the FEM and Somigliana’s integral formula for the boundary problem in 3D medium is considered. The algorithm is modified for the case of inhomogeneous medium. Some practical boundary problems of geological and mechanical earth models are solved by algorithms discussed.
A design of flash analog-to-digital converter in 180 nm CMOS process with high effective number of bits
Authors: Budanov D , Korotkov A
Published: July 2019

High speed flash analog-to-digital converters are used in modern high-performance telecommunication systems. Furthermore, high effective resolution of such converter should be provided. The paper presents a design of a flash analog-to-digital converter with high effective number of bits. As an example, the 8-bit flash ADC in 180 nm CMOS has been implemented. Simulation confirms efficiency of proposed design. The effective resolution of presented design achieves 6.9 bits.
A new algorithm for processing the absorption and scattering signals of laser radiation on a blood vessel and human tissues
Authors: Davydov R V , Antonov V I , Yushkova V V , Grebenikova N M , Dudkin V I
Published: July 2019

The article describes a new algorithm for processing the pulse wave, which is formed from the registered signals of absorption and scattering of laser radiation on a blood vessel or vein and human tissues. A new method of tuning the optical part of the pulse oximeter is proposed to increase the reliability of the rapid diagnosis results of the human condition. Experimental data on studies of the health status of various people are presented.
The signal processing algorithm of automotive FMCW radars with an extended range of speed estimation
Authors: Ivanov S I , Kuptsov V D , Fedotov A A
Published: July 2019

The paper considers the algorithm for estimating the speed and distance to the target as applied to the mm wave automotive radar with linear FMCW. To extend the range of target speed estimation, a signal in the form of a Chirp Sequence Waveform is used with a shift of the initial frequency in the adjacent chirps of the frame. A mathematical model of the received microwave signal is proposed, taking into account a wide range of velocity changes of the target, as well as the effect of additive white Gaussian noise on the radar receiver. It is shown that the signal-to-noise ratio of 10 dB is necessary for the algorithm to work, and that the unambiguity and consistency of the speed estimate is limited by the first two Nyquist zones for the Doppler frequency.
Analysis of the possibility of using the system for small satellite de-orbiting based on an aerodynamic stabilizer, taking into account the physical features of the Earth’s upper atmosphere
Authors: Tkachenko I S , Korovin M D , Krestina A V
Published: July 2019

The paper presents an analysis of performance of a satellite de-orbiting system that utilizes a deployable aerodynamic stabilizer for controling the angular motion of a spacecraft in order to ensure the correct orientation of the breaking impulse. The problem of determining the shape of the stabilizer, considering its performance requirements and technological constraints has been adressed. The effectiveness of proposed design of the stabilizer for the prototype spacecraft based on the “AIST” small satellite was evaluated using two methods – calculation of aerodynamic forces generated by the rarefied gas flow using the experimental coefficients of the form and stochastic modelling using software. According to the calculations, the proposed aerodynamic system would be capable of providing sufficient stabilizing influence to satisfy the required stabilization time and permissible angle of attack deviation constraints. The range of orbits, where the aerodynamic stabilizer would remain efficient, have been determined with regards to atmospheric properties and design constraints, imposed by mass and size limitations of the system and the de-orbiting time.
Start Control for the MMC-HVDC
Authors: Zhang Xiaoliang , Ning Lianhui , Yin Yanjiao , Zhao Boyang , Han Jingwen , Hu Fangkai
Published: July 2019

This paper designs the control strategies and start procedure of MMC-HVDC. The start procedure consists of three stages, uncontrollable charging stage, controllable charging stage and power-raising stage. The current circuit is analysed and the equivalent circuit is obtained in uncontrolled charging stage. The computational formula of current-limit resistor is obtained in the uncontrollable stage. Two different control strategies to further charge the capacitors to the rated voltage in controllable charging stage are designed. Strategy one makes use of DC voltage control and balancing strategy of capacitor voltage while Strategy two divides the capacitors of one arm into two groups. In power-raising stage, to avoid the impact of power step, slope control is used in power outer loop. Finally, a simulation model is established in the PSCAD/EMTDC. The simulation results show that the effectiveness and rationality of the designed start procedure and control strategies
Analysis and Protection of DC Short Circuit Fault in True Bipolar MMC-HVDC System
Authors: Liu N M , Ning L H , Wu D , Su Y , Teng H D , Gao L
Published: July 2019

With the introduction of modular multilevel converter (MMC), the development of high voltage direct current transmission (HVDC) technology has been promoted. As flexible DC transmission technology is gradually extended to overhead line transmission, DC fault clearing and fault protection issues have become particularly important. In this paper, the current characteristics of different stages of DC short-circuit faults are studied for the overhead line true bipolar MMC-HVDC system. The simulation model of the true bipolar system is built by PSCAD/EMTDC software. The simulation results verify the correctness of the analytical calculation. Finally, in order to suppress the sudden increase of bridge arm current during fault, a bridge arm protection method for DC short-circuit fault is proposed. The simulation results show that the protection method can effectively protect the sub-module device in case of fault, and can Shorten the fault recovery time, this protection method effectively protects the devices of the AC system and sub-modules.
Research on Key Technical Parameters of 1100kV Live Tank Circuit Breaker for UHVDC Converter Station
Authors: Du Ning , Xiang Zutao , Han Bin , Yang Yue , Xiang Changyuan
Published: July 2019

Many of UHVDC transmission projects planned and under construction are hierarchical connected to 500kV and 1000kV AC grid in China. Live tank circuit breakers are selected for switching 1000kV filters. During the development of 1100kV live tank circuit breakers, the closing inrush current and transient recovery voltage are key factors for structure of extinguishing chamber of circuit breakers. In this paper, the above factors are analyzed by simulation, and key technical parameters of 1100kV live tank circuit breakers for UHVDC converter station are proposed.
Research on Control Strategy of Grid-Connected Converter Based on Virtual Inertia
Authors: Ke Wang , Guangzhu Wang , Chengxi Li
Published: July 2019

As the DC microgrid has low inertia, this paper draws on the virtual synchronous machine technology to propose and control a new virtual inertial control strategy. This control strategy enables the grid-connected converter to have both AC inertia and DC inertia. By small signal decomposition, the transfer function block diagram of the system is established. The effects of different inertial parameters on the system’s AC inertia and DC inertia are studied. The dynamic characteristic analysis and simulation results show that the proposed virtual inertial control can effectively suppress the fluctuation of DC bus voltage and AC power and increase the AC and DC inertia of the converter.
An Inverter Parallel Control Strategy Research on Variable Virtual Impedance
Authors: Li Weibo , Xu Zhihao , Xu Cong , Li Wei , Li Qi
Published: July 2019

In order to solve the imbalance distribution of reactive power in the power system caused by different line impedance in parallel muti-inverter system, This paper analyses the deficiency of traditional droop control and the causes of reactive current circulation. Double closed loop control based on inverter voltage and current, it studies the influence of different system parameters on the equivalent impedance of the inverter, according to the study it introduce virtual impedance, the real-time reactive power is distributed to a given reactive power through the inverter’s control system, and then the inverter control system estimates the virtual impedance by deviating the reactive power from the given reactive power. Simulation results show that the method of adjust reactive power on line have certain effectiveness and feasibility.
Coordinative Control Strategy for Power Electronic Transformer with Microgrid Connection
Authors: Li Zheng , Zheng Tao , Ma Hongyue , Wang Jiahao
Published: July 2019

Power electronic transformer integrates rich forms of electrical interfaces and is able to realize a flexible, accurate and continuous regulation of the network power flow. It’s a promising power equipment to act as the ‘energy router’ in the energy internet, achieving a large-scale access and efficient utilization of distributed energy resources. To solve the DC-bus voltage fluctuation of PET caused by the randomness of the output power of microgrid, a coordinative control strategy between the input stage, isolation stage of PET and the microgrid is proposed. The frequency-domain analysing method is used compare the characteristics of the power fluctuation response under the proposed coordinative control strategy and a traditional control strategy. The simulation results indicate that the proposed control strategy can achieve the stability and fast convergence of DC bus voltage, which proves the correctness and advancement of the coordinative control strategy.
Research on PMSM Low-speed Sensorless Control Strategy based on Rotating High Frequency Injection Method
Authors: Tang Hui , Yin Dejun
Published: July 2019

In this paper, by studying the Permanent Magnet Synchronous Motor (PMSM) position sensorless control strategy, a method for error compensation of current responsed by high frequency error signal is proposed. Since the high-frequency carrier current contained in the stator current causes the erroneous adjustment of the current regulator, the control system contains a high-frequency error signal, which affects the motor rotor position and speed estimation accuracy. The high-frequency error voltage signal is extracted in the stationaryα − β coordinate system, and the high-frequency error response current in the stator current is estimated, and the estimation system is compensated. The PMSM position sensorless control system based on the rotating high frequency voltage injection method and the Matlab-Simulink system model of the error compensation are established. The results show that the speed and position estimation are more accurate after error compensation, and the steady-state error is smaller, which improves the smoothness of the motor at low speed.
Distribution Network Planning with Comprehensive Economy and Reliability
Authors: Du Wei , Lu Mengke , Li Deyi
Published: July 2019

From the perspective of reliability and economy of distribution network, this paper combines the layout of network frame and the configuration of section switch and contact line, and obtains many plannings that coordinate economy and reliability. Firstly, considering the grid planning, a multi-objective optimization planning model of the distribution network frame with the lowest investment and operating costs and the best reliability index is established. When solving the model, the minimum spanning tree algorithm is used to avoid the generation of infeasible solutions and reduce the computational burden. This paper improves the minimum spanning tree algorithm, when algorithm iteratively generates a new solution, the sum of the reduction rate of economic index and the growth rate of reliability index is used to be the objective function in the iterative process, so that the multi-objective problem is transformed into a single objective problem. The preference factor of the decision-maker is given by weight assignment. And the algorithm is extended to multi-power planning. Secondly, considering the configuration of section switch and contact line, the nonlinear mixed integer programming model corresponding to the system is established, and the Pareto optimal solution set is generated by the NSGA-II algorithm. Then, the Pareto optimal solution set is converted into a series of corresponding planning schemes that the designer can select. Finally, the validity and correctness of the proposed method are verified by the analysis of single-source and multi-source distribution network examples.
A Study on Power Quality Transient Disturbance Location Method
Authors: Zhang Huaying , Hu Ziheng , Li Yan , Ai Jingwen
Published: July 2019

Due to periodic variation of power signal and various disturbances present during sampling process, resulting background gradient affects the accuracy of disturbance detection. In order to solve this problem, this paper proposes a power quality transient disturbance location method based on morphological edge detection, and introduces a soft threshold quantitative evaluation method to improve its accuracy. Firstly, an evaluation method of filtering effect is proposed, and original signal is filtered by adaptively choosing size of structuring elements. Then, Top-Hat transform of morphological gradient is performed by flat structuring elements to suppress background gradient, and the location result is initially obtained. Finally, combined with soft threshold processing method, the location of power quality transient disturbance is realized. Simulation analysis of a series of power quality transient disturbances shows that this algorithm has accurate location results, strong capacity of resisting disturbance and good versatility.
Regeneration Technology of Ex-service SF6 Adsorbent Using Vacuum Heat Treatment
Authors: Wen Chunlei , Wei Gang , Hu Min , Yin Hua , Yang Jun , Li Cuiying , Zhang Haiyan
Published: July 2019

Ex-service SF6 adsorbent is toxic, and its direct dumping may cause environmental damages. Therefore, studying the environmental-friendly processing of ex-service SF6 adsorbent has important social values. In this study, the adsorption components of the ex-service SF6 adsorbent were analyzed by thermogravimetry. In order to study the most economical and effective regeneration method of SF6 adsorbent, the regeneration technology of vacuum heat treatment was proposed, and the regeneration theory of vacuum heat treatment concerning adsorbent was elaborated, then followed by the experiment of vacuum heat treatment. By combining with infrared spectroscopy, the content change of harmful ingredient in adsorbent was analyzed, focused on the confirmation of vacuum heat treatment regeneration temperature, regeneration time and vacuum pressure, and the test verification on adsorption isothermal curve was performed to determine the desorption capacity of SF6 molecular sieve adsorbent recycled. We found that vacuum heating can increase performance recovery rate by 85%–90%.