bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultra-strong magnon-photon coupling induced in the photonic crystals with an YGaGeIG defect
Authors: Zhang Chi , Shi Yongzhang , Zhang Weihua , Jiang Changjun , Chai Guozhi
Published: July 2019

In this work, magnon-photon couplings are studied by using a point defect cavity in two dimensional simple cubic structure photonic crystals. The point defect is introduced by replacing one of the lattice points (copper cylinder) with a Ca and Ge element doped yttrium-iron-garnet (YCaGeIG) cylinder. Ultrastrong magnon-photon coupling is detected, with the coupling strength of 2.10 GHz, which constitutes about 23.4% of the photon energy compared to the cavity frequency around 8.98 GHz. The ultrastrong coupling might be derived from the large spin numbers of the ferrite cylinder. This work may open a way to tune the coupling induced in the photonic crystals with a magnetic defect.
Laboratory setup for rapid in situ powder X-ray diffraction elucidating Ni particle formation in supercritical methanol
Authors: Gjørup Frederik H. , Ahlburg Jakob V. , Christensen Mogens
Published: July 2019

The design and function of a custom-made Soller slit for a laboratory 2D area detector is presented through a series of demonstration images and an in situ experiment following the formation of nickel particles in supercritical methanol. The in situ experiment is performed in a capillary sample environment, modified for a laboratory scale Rigaku Smartlab diffractometer, and with a temperature range of 300–1050 K. The formation of nickel particles was followed successfully using laboratory in situ X-ray powder diffraction with a time resolution in the order of 27 s. Observations from the area detector images showed the appearance of three distinct phases during the reaction: Ni3(NO3)2(OH)4, NiO, and Ni. The images were linearly integrated and analyzed using Rietveld refinement. A reaction mechanism is proposed based on an evaluation of the weight fractions and scattering factors as a function of reaction time.
Heterogeneous dynamics of unentangled chains in polymer nanocomposites
Authors: Dai Li-Jun , Fu Cui-Liu , Zhu You-Liang , Sun Zhao-Yan
Published: July 2019

We present a systematic investigation on the effect of adding nanoparticles on the dynamics of polymer chains by using coarse-grained molecular dynamics simulation. The dynamics is characterized by three aspects: molecular motion, relaxation at different length scales, and dynamical heterogeneity. It is found that the motion of polymer chains slows down and the deviation from Gaussian distribution becomes more pronounced with increasing nanoparticle volume fractions. For polymer nanocomposites with R ≤ Rg, the relaxation at the wave vector q = 7.0 displays multistep decay, consistent with the previous reports in strongly interacting polymer nanocomposites. Moreover, a qualitatively universal law is established that dynamic heterogeneity at whole chain’s scale follows a nonmonotonic increase with increasing nanoparticle loadings, where the volume fraction of the maximum dynamic heterogeneity corresponds to the particle loading when the average distance between nanoparticles is equal to the Kuhn length of polymer chains. We show that the decoupling between whole chain’s dynamics and segment dynamics is responsible for the nonmonotonic behavior of dynamic heterogeneity of whole chains.
Enhanced electro-mechanical coupling of TiN/Ce0.8Gd0.2O1.9 thin film electrostrictor
Authors: Santucci Simone , Zhang Haiwu , Sanna Simone , Pryds Nini , Esposito Vincenzo
Published: July 2019

Gadolium doped ceria, Gd:CeO2 (CGO), have recently been shown to possess an exceptional high electrostriction coefficient (Q), which is at the least three orders of magnitude larger than the best performing lead-based electrostrictors, e.g. Pb(Mn1/3Nb2/3)O3. Herein, we show that CGO thin films fabricated by a pulsed laser deposition method can be directly integrated onto the Si substrate by using TiN films of few nanometers as functional electrodes. The exceptional good coupling between TiN and Ce0.8Gd0.2O1.9 yields a high electrostriction coefficient of Qe = 40 m4 C−2 and a superior electrochemomechanical stability with respect to the metal electrodes.
Plasma ignition and detection for in-situ cleaning of 1.3 GHz 9-cell cavities
Authors: Berrutti P. , Giaccone B. , Martinello M. , Grassellino A. , Khabiboulline T. , Doleans M. , Kim S. , Gonnella D. , Lanza G. , Ross M.
Published: July 2019

Superconducting radio frequency cavities performance preservation is crucial, from vertical test to accelerator operation. Field emission is still one of the performance limiting factors to overcome, and plasma cleaning has been proven successful by the Spallation Neutron Source (SNS), in cleaning field emitters (hydrocarbon contaminants) and increasing the work function of Nb. The cleaning for Linac Coherent Light Source-II will follow the same plasma composition adopted at SNS, which allows in situ processing of cavities installed in cryomodules. A novel method for plasma ignition has been developed at the Fermi National Accelerator Laboratory: a plasma glow discharge is ignited using high order modes to overcome limitations imposed by the fundamental power coupler. The plasma can be easily ignited and tuned in each of the cavity cells using low radio frequency (RF) power, from 100 W to as low as 2 W depending on the gas and pressure. A method for RF plasma detection has been developed: the plasma location is identified within the cavity without the need of cameras. The presented method can be applied to other multicell cavity designs, even for accelerators where the coupling for the fundamental modes at room temperature is very weak.
Combination of pulsed light heating thermoreflectance and laser-heated diamond anvil cell for in-situ high pressure-temperature thermal diffusivity measurements
Authors: Hasegawa Akira , Yagi Takashi , Ohta Kenji
Published: July 2019

By combining thermoreflectance measurements and laser heated diamond anvil cell (LHDAC) techniques, an instrument for the measurement of in situ high pressure-temperature thermal diffusivity of materials was developed. In an LHDAC system, high-power continuous-wave laser beams irradiate both faces of a disk-shaped metal sample loaded into diamond anvil cells (DACs), to maintain a stable high-temperature condition. During the operation of the LHDAC system, temperature of the sample is determined from the thermal radiation spectrum between 640 and 740 nm to fit Planck’s law. Subsequently, a pulsed laser beam irradiates the metal disk to induce a temperature gradient inside the sample, and the transient temperature, caused by heat diffusion, is measured by a continuous wave probe laser based on the thermoreflectance phenomenon. We determined the thermal conductivities of Pt and Fe up to approximately 60 GPa and 2000 K using the measured thermal diffusivities and obtained values consistent with previous works. The uncertainties in the pressure and the temperature are estimated to be approximately 10%, and that in the thermal conductivity is estimated to approximately 15%. The system developed in this study enables us to determine thermal transport properties of materials under pressure–temperature conditions of the deep Earth.
Higher-order Darboux transformations for the massless Dirac equation at zero energy
Authors: Schulze-Halberg Axel
Published: July 2019

We construct higher-order Darboux transformations for the two-dimensional massless Dirac equation at zero energy. Both standard and confluent transformations are applicable. Our construction is based on a higher-order extension of the Darboux transformation for Schrödinger equations with quadratically energy-dependent potentials [J. Lin et al., Phys. Lett. A 362, 212 (2007)].
Diamagnetic droplet microfluidics applied to single-cell sorting
Authors: Buryk-Iggers Stephanie , Kieda Jennifer , Tsai Scott S. H.
Published: July 2019

The heterogeneity of diseased tissue causes major challenges in the detection and treatment of disease. Such challenges have motivated the development of tools for single-cell isolation and analysis. However, many cell isolation methods in microfluidics rely on the use of cell-labeling steps or expose cells to potentially harmful forces. Here, we present a microfluidic method for label-free control of cell-encapsulating biocompatible droplets using negative magnetophoresis. Our system is distinguished from previous microfluidic diamagnetic sorting approaches by the encapsulation of the cells inside droplets, which isolates the cells from the magnetic continuous phase. The droplet phase is comprised of cells suspended in their growth culture medium, and all of the magnetic content is contained in the oil-based continuous phase. At a flow-focusing junction, empty droplets and cell-encapsulating droplets are both generated and surrounded by the magnetic continuous phase. Cell encapsulation produces a size distinction between empty droplets and cell-encapsulated droplets. Through the application of a permanent magnet to the system, diamagnetic size-based sorting of empty droplets from cell-encapsulated droplets is achieved with a purity of ∼84% in a single pass. Additionally, since the encapsulated cells are completely isolated from the magnetic content in the continuous phase, 88% cell-viability is observed after a two-hour incubation period. If combined with a single-cell assay, this system can provide label-free isolation of viable cells at a high purity for subsequent downstream analysis.
Hydrodynamic interactions and the diffusivity of spheroidal particles
Authors: Marath Navaneeth K. , Wettlaufer John S.
Published: July 2019

It is intuitive that the diffusivity of an isolated particle differs from those in a monodisperse suspension, in which hydrodynamic interactions between the particles are operative. Batchelor [J. Fluid Mech. 74, 1–29 (1976) and J. Fluid Mech. 131, 155–175 (1983)] calculated how hydrodynamic interactions influenced the diffusivity of a dilute suspension of spherical particles, and Russel et al. [Colloidal Dispersions (Cambridge University Press, 1991)] and Brady [J. Fluid Mech. 272, 109–134 (1994)] treated nondilute (higher particle volume fraction) suspensions. Although most particles lack perfect sphericity, little is known about the effects of hydrodynamic interactions on the diffusivity of spheroidal particles, which are the simplest shapes that can be used to model anisotropic particles. Here, we calculate the effects of hydrodynamic interactions on the translational and rotational diffusivities of spheroidal particles of arbitrary aspect ratio in dilute monodisperse suspensions. We find that the translational and rotational diffusivities of prolate spheroids are more sensitive to eccentricity than for oblate spheroids. The origin of the hydrodynamic anisotropy is that found in the stresslet field for the induced-dipole interaction. However, in the dilute limit, the effects of anisotropy are at the level of a few percent. These effects have influence on a vast range of settings, from partially frozen colloidal suspensions to the dynamics of cytoplasm.
Rosette-scan video-rate atomic force microscopy: Trajectory patterning and control design
Authors: Nikooienejad Nastaran , Maroufi Mohammad , Moheimani S. O. Reza
Published: July 2019

We present an analysis and a systematic design methodology for a novel nonraster scan method based on a rosette pattern and demonstrate its application in video-rate atomic force microscopy. This pattern is traced when the lateral axes of a parallel kinematic scanner are commanded to follow a combination of two sinusoids with identical amplitudes and different frequencies. We design an internal-model-based controller to enhance the tracking performance of this pattern and implement the scheme on a microelectromechanical system scanner. The results reveal high-precision tracking of the rosette pattern in order to acquire time-lapsed atomic force microscope images at the rate of 10 frames/s.
Theoretical investigation of the interface fluctuation causing low channel conductivity at SiO2/SiC interfaces through the self-energy and average Green’s function
Authors: Yoshioka Hironori
Published: July 2019

The low channel mobility and the high interface state density at SiO2/SiC interfaces is quantitatively explained by introducing potential fluctuation at interfaces. The density of states with the perturbation potential is calculated through the self-energy and average Green’s function, and the interface state density is determined by assuming that localized states are interface trap states. The mobility is obtained by using the Fermi’s golden rule, the Boltzmann’s transport equation, and the relaxation time approximation. The parameters characterizing the potential fluctuation is estimated so as to reproduce the mobility (100 cm2V−1s−1) and the interface state density (5.4×1012 cm−2) that was obtained in a previous report by analyzing the experimental results of a MOSFET: the root-mean-square of the potential being more than 0.02 eV and the correlation length being less than few nm.
The first order atomic fragment approach—An orbital-free implementation of density functional theory
Authors: Finzel K.
Published: July 2019

An orbital-free implementation of the original Hohenberg-Kohn theorems is presented, making use of the scaling properties from a fictitious Kohn-Sham system, but without reintroducing orbitals. The first order fragment approach does not contain data or parameters that are fitted to the final outcome of the molecular orbital-free calculation and thus represents a parameter-free implementation of orbital-free density functional theory, although it requires the precalculation of atomic data. Consequently, the proposed method is not limited to a specific type of molecule or chemical bonding. The different approximation levels arise from including (first order) or neglecting (zeroth order) the dependency between the potential and the electron density, which in the bifunctional approach are formally treated as independent variables.
Mo6S8-based single-metal-atom catalysts for direct methane to methanol conversion
Authors: Zhang Hao-Tian , Liu Cheng , Liu Ping , Hu Yun Hang
Published: July 2019

The single atom catalysts have been attracting much attention for catalysis. In this work, the significant influence of single-metal-atom (M = K, Ti, Fe, Co, Ni, Cu, Rh) doping on a Mo6S8 cluster was revealed for the direct methane to methanol conversion in water stream using density functional theory calculations. It was found that all single atom dopants help to facilitate the conversion via the steam reforming of methane (SRM). The single Fe atom on Mo6S8 (Fe—Mo6S8) exhibits the most significant promoting effect, which is followed by Ni, Co, Rh—Mo6S8 > K, Ti, Cu—Mo6S8 > Mo6S8 in a decreasing sequence. The enhanced activity by single atom doping on Mo6S8 is mainly associated with the interplay between the ensemble effect via the direct participation of an active M dopant and the site confinement imposed by doping of a single M atom, in tuning the methane conversion and methanol selectivity. It generates the new active center, M, which confines the SRM to occur at the M—Mo bridge sites and facilitates the selective production of methanol. A good single-atom promoter should not only bind *OH or *O moderately, being strongly enough to help water dissociation and weakly enough to allow the oxidation of methane, but also impose the confinement effect to facilitate the C—O bond association and production of methanol. Our results highlight the importance of the interplay among ligand, ensemble, and confinement effects in promoting the complex SRM over single atom catalysts.
Weakly bound molecular dimers: Intramolecular vibrational fundamentals, overtones, and tunneling splittings from full-dimensional quantum calculations using compact contracted bases of intramolecular and low-energy rigid-monomer intermolecular eigenstates
Authors: Felker Peter M. , Bačić Zlatko
Published: July 2019

We present a method for the efficient calculation of intramolecular vibrational frequencies, and their tunneling splittings, in weakly bound molecular dimers, together with the intermolecular vibrational states within each intramolecular vibrational manifold. The approach involves the partitioning of the dimer’s vibrational Hamiltonian into two reduced-dimension Hamiltonians, a rigid-monomer one for the intermolecular vibrations and the other for all intramolecular vibrational degrees of freedom, and a remainder. The eigenstates of the two reduced-dimension Hamiltonians are used to build up a product contracted basis for the diagonalization of the full vibrational Hamiltonian. The key idea is that because of weak coupling between inter- and intra-molecular vibrational modes, the full-dimensional eigenstates in the low-energy portions of the manifolds associated with the intramolecular vibrational excitations can be computed accurately in a compact basis that includes a relatively small number of rigid-monomer intermolecular eigenstates, spanning a range of energies much below those of the intramolecular vibrational states of interest. In the application to the six-dimensional (6D) problem of (HF)2, we show that this approach produces results in excellent agreement with those in the literature, with a fraction of the basis states required by other methods. In fact, accurate energies of the intramolecular vibrational fundamentals and overtones are obtained using 6D bases that include 4D rigid-monomer intermolecular vibrational eigenstates extending to only 500–1000 cm−1, far below the HF-stretch fundamental of about 4000 cm−1. The method thus holds particular promise with respect to calculations on complexes with greater numbers of vibrational degrees of freedom.
Insights into 33phosphorus utilisation from Fe- and Al-hydroxides in Luvisol and Ferralsol subsoils
Authors: Koch Maximilian , Guppy Christopher , Amelung Wulf , Gypser Stella , Bol Roland , Seidel Sabine , Siebers Nina
Published: July 2019

There is currently relatively little available information on subsoil phosphorus (P) use for crop production as a function of soil order. In this study, a rhizobox experiment was performed using subsoils of two reference soil groups, an Orthic Ferralsol and a Haplic Luvisol. To evaluate the immediate P uptake by wheat (Triticum aestivum L.) from different subsoil P pools during 14 days of growth, subsoil bands were spiked with KH2PO4 solution associated to Fe-hydroxide (33P-Fe), to Al-hydroxide (33P-Al), in free form (33P-OrthoP), or in trace amounts without any additional 31P (33P-NoP). At the beginning of the experiment, the soil water content was set at 75% of water-holding capacity, corresponding to an initial soil matric potential of −12 ± 1 kPa. During plant growth, soil moisture decreased in both soils, but soil matric potentials in both soils did not drop below field capacity (−33 kPa; pF 2.5). The shoot dry weights of the Ferralsol were 1.2 to 1.8 times those of the Luvisol. Despite elevated soil P availability in the Luvisol, shoot P concentrations did not differ between the two soils. The amount of 33P taken up by the shoots from the oxide phases was 15% to 40% greater in the Ferralsol treatments than in those in the Luvisol treatments. It was concluded that the more favourable physical soil conditions facilitated 33P uptake from both oxidic phases from the Ferralsol subsoil relative to the Luvisol subsoil, despite better P phytoavailability in the latter.
Prediction of soil clay minerals from some soil properties with use of feature selection algorithm and ANFIS methods
Authors: Najafi-Ghiri Mahdi , Mokarram Marzieh , Owliaie Hamid Reza
Published: July 2019

Researchers use different methods to investigate and quantify clay minerals. X-ray diffraction is a common and widespread approach for clay mineralogy investigation, but is time-consuming and expensive, especially in highly calcareous soils. The aim of this research was prediction of clay minerals in calcareous soils of southern Iran using a feature selection algorithm and adaptive neuro-fuzzy inference system (ANFIS) methods. Fifty soil samples from different climatic regions of southern Iran were collected and different climatic, soil properties and clay minerals were determined using X-ray diffraction. Feature selection algorithms were used for selection of the best feature subset for prediction of clay mineral types along with two sets of training and testing data. Results indicated that the best feature subset by Best-First for prediction of illite was cation exchange capacity (CEC), sand, total potassium, silt and agroclimatic index (correlation coefficient (R) = 0.99 for training and testing data); for smectite was precipitation, temperature, evapotranspiration and CEC (R = 0.89 and 0.87 for training and testing data respectively); and for palygorskite was precipitation, temperature, evapotranspiration and calcium carbonate equivalent (CCE) (R = 0.98 for training and testing data). An attempt was made to predict clay minerals type by ANFIS using selected data from the feature selection algorithm. The evaluation of method by calculating root mean square error (RMSE), mean absolute error (MAE) and R indicated that the ANFIS method may be suitable for illite, chlorite, smectite and palygorskite prediction (RMSE, MAE and R of 0.001–0.028, 0.004–0.012 and 0.67–0.89 respectively for training and testing data). Comparison of data for all clay minerals showed that ANFIS method did not predict illite and chlorite as well as other minerals in the studied soils.
Manifestation of room-temperature superconductivity in thin films fabricated of YBa2Cu3O7–δ
Authors: Kudriashov A V , Klyachkin L E , Malyarenko A M , Nashchekin A V , Romanov V V , Rykov S A , Bagraev N T
Published: July 2019

We present manifestations of room temperature superconductivity in thin films fabricated of YBa2Cu3O7–δ
(YBCO) on the substrate of NdGaO3
(110). We show that the static magnetic susceptibility measurements demonstrate the Meissner effect in weak magnetic fields at room temperature. In addition, the oscillations of the magnetic susceptibility are revealed in external magnetic field, which can be interpreted as the quantization of magnetic flux through inclusions, with superconducting domains around them and the observation of the field-dependent steps that seem to be of evidence the second-order phase transition of domains. The results obtained are in a good agreement with the data of tunneling I-V curves. Finally, we suggest few further experiments that could confirm our hypothesis.
Automatic lung segmentation method in computed tomography scans
Authors: Shariaty F , Hosseinlou S , Rud’ V Yu
Published: July 2019

Lung segmentation in Computed Tomography (CT) images is one of the important steps in Computer Aided Diagnosis (CADx) systems. This paper has proposed a completely automatic algorithm for recognition and segmentation of lungs in 3D pulmonary X-ray CT images. The advantage of this method is separation of attached nodules to the lung wall which are removed in ordinary lung segmentation methods. This method is based on thresholding algorithm that identifies attached nodules with some morphological operations. This method applied to 20 lung CT images has shown that eventually the lungs were correctly segmented. The advantage of using a simple thresholding algorithm is high speed, e.g. the time of the lung segmentation for 300 images is less than 10 seconds.
Plasmonic polarization-sensitive detector of terahertz radiation
Authors: Gorbenko I V , Kachorovsky V Yu , Shur M S
Published: July 2019

We develop a theory of the helicity driven nonlinear DC response of gated two-dimensional electron gas to the terahertz radiation. We demonstrate that the helicity-sensitive part of the response dramatically increases in the vicinity of the plasmonic resonances and oscillates with the phase shift between excitation signals on the source and drain. The resonance line shape is an asymmetric function of the frequency deviation from the resonance. In contrast, the helicity-insensitive part of the response is symmetrical. These properties yield significant advantage for using plasmonic detectors as helicity-sensitive terahertz and far infrared spectrometers and interferometers.
Phase control of the fractional conductance of silicon nanosandwich-structures
Authors: Rul’ N I , Bagraev N T , Klyachkin L E , Malyarenko A M
Published: July 2019

We present the experimental data of the electric features of the silicon nanosandwichstructures obtained by silicon planar technology in the frameworks of the Hall geometry that represent the ultra-shallow silicon quantum well of 2 nm wide that are confined by delta-barrier heavily doped with boron, which create the edge channels used as the phase controllers of electric signals. The formation of the negative-U dipole boron centers, which appear to confine the edge channels, results in the effective mass dropping and corresponding reduction of the electron-electron interaction thereby giving rise to the macroscopic quantum phenomena at high temperatures up to room temperature. The phase control of the longitudinal conductance is observed by changing either the magnitude of the source-drain current or the voltage applied to the external gate of the silicon nanosandwiches within the quantum Faraday effect.
On specific features of the endoscopic image processing
Authors: Galeeva M A , Baranov M A , Pavlov V A , Velichko E N , Zavjalov S V , Govorov I E , Pervunina T M , Komlichenko E V
Published: July 2019

Main principles of endoscopic image processing are considered. Specific characteristics of such images and complexities in their classification are discussed. We suggest that several features may be regarded as specific signs that can be used to discriminate between benign and malignant loci. The methods of colour histograms, gradients and texture analysis are considered and discussed.
Simulation of the effect of peculiarities of the energy spectrum structure on the Hall coefficient behaviour in high- temperature superconductors
Authors: Amelina A A , Martynova O A , Gasumyants V E
Published: July 2019

In this paper, we have investigated the influence of peculiarities of the normal-state energy spectrum structure in high-temperature superconductors on the temperature dependences of the Hall coefficient, RH
. Methods for accounting different specific features of the charge-carrier system when approximating the differential Hall conductivity function were proposed and used for simulating the RH
(T) dependences in the framework of a narrow-band model. Simulation results show the Hall coefficient to be most sensitive to the existence of an asymmetry of the dispersion law. Taking this property into account one can obtain the calculated RH
(T) curves corresponding well to the experimental ones observed for samples of the Y-based system with different deviations from the stoichiometric composition. This finding corresponds well to results obtained previously when analyzing the Nernst coefficient behavior in the same system and should be used for a further development of the approach to the joint quantitative analysis of the normal-state electron transport in high-temperature superconductors.
An application of the spectral Radon–Nikodym approach to fluorescence dynamics study of cold atomic cloud ensemble
Authors: Bozhokin S V , Malyshkin V G
Published: July 2019

A fluorescence dynamics of a cold atomic cloud, laser–cooled to a very low temperature, optically excited by a short laser impulse is calculated by applying non–stationary Schrödinger equation to the system of atoms and electromagnetic field. The solution gives fluorescence time–relaxation dependence, with relaxation time distribution depending on the system itself and external electromagnetic field applied. The distribution of the relaxation rates changes, when an external electric field affecting the atomic ensemble is applied. To analyze the relaxation process a novel Radon–Nikodym approach is applied: the relaxation curve is not piece–wise interpolated, but instead is converted to a matrix, the eigenvalues of which provide relaxation rate distribution. In contrasts to the random matrix theory, where the weights, corresponding to an eigenvalue, are considered equal, in this work the weight, corresponding to an individual eigenvalue, is determined by the Lebesgue integral quadrature weights.
Radiomics as a basis for transformation of radiologists skills and partnership
Authors: Meldo A A , Utkin L V
Published: July 2019

Artificial intelligence (AI) in the fourth industrial revolution is integrated into the life of modern society. Modern computer technology and software are opening the way for implementation of AI also in medicine. In fact, the position of AI in relation to medicine was unacceptable by the medical community a few years ago. Nevertheless, it is obvious today that the development of IT, including AI, has an impact on the quality of medical care, particularly of diagnosis. Integration of AI systems as an organisational innovation in the work of medical institutions is a significant challenge. It involves the revision of some aspects of the professional education and of issues of the interdisciplinary interaction. A scheme of effective cooperation of specialists of IT and radiologists is proposed in the paper. It aims at the permanent development of AI systems and their implementation in a daily medical practice and proposed by an example of the medical intellectual computer-aided diagnostic system Doctor AIzimov.
On features of implementation of SEFDM-transmitter with optimal shape of envelope
Authors: Smirnova E N , Ovsyannikova A S , Zavjalov S V , Dong G
Published: July 2019

This article describes joint use of two improving spectral efficiency algorithms for multi-frequency signals: SEFDM (Spectrally Efficient Frequency Division Multiplexing) technology and smoothed envelopes. SEFDM-signals are generated with IFFT algorithm. Transmitter with different envelope shapes is realized on SDR-platform HackRF One. Waveforms, spectra and PAPR (peak-to-average power ratio) of SEFDM-signals were obtained from simulation, vector signal generator and SDR-platform.
A study of temperature dependence of phase shift in optoelectronic path of direction finder channels
Authors: Sinicyna E A , Galichina A A , Lukiyanov A S , Shishkov A N , Podstrigaev A S , Davydov V V
Published: July 2019

The need to study the temperature dependence of phase difference between optical signals in information transmission channels for direction finder stations is justified. The method is proposed how to determine the phase difference. The experimental results are presented for different cases of temperature change influence on optoelectronic path of direction finder.
A temperature effect study on the laser diode module spectral characteristics
Authors: Petrenko A A , Mikhailovskii G A , Kotova E I , Petrov A B , Bugrov V E
Published: July 2019

The paper presents the study results of the semiconductor laser active medium temperature effect, that changes in time during its operation, on its output spectral characteristics. Experimental dependences of the diode laser emission spectra on the laser crystal temperature in the range from 296 to 320 K are investigated. Using a heat fluxes computer model the possible reasons were analyzed for the time variation of the laser diode module spectral characteristics with several single emitters that are fixed on the ladder platform. The obtained results can be used for the large-scale laser diode modules design, including a large number of emitters, with high requirements for the output characteristics stability. Thermal fields and isothermal surfaces for a laser diode module with total thermal loads exceeding 30 W are studied.
Imbalance Mechanism of Capacitor Voltage and Control Strategy for Hybrid Modular Multilevel Converter with Negative Output
Authors: Gao L , Ning L H , Yin Y J , Wu D , Liu N M , Teng H D
Published: July 2019

In a flexible DC transmission system with a large-capacity overhead line, a hybrid modular multilevel converter (MMC) consisting of the half bridge submodule (HBSM) and the full bridge submodule(FBSM) has become a research hotspot due to its self-cleaning capability of DC short-circuit fault. Under the operating conditions of reducing the DC voltage, due to the different charging and discharging characteristics of the half bridge submodule and the full bridge submodule, a capacitor voltage imbalance may occur between the two submodules. This paper first studies the number configuration of half-bridge submodules and full-bridge sub-modules in modular multilevel converters. Then, the capacitor voltage imbalance mechanism of the hybrid MMC sub-module is analyzed in detail, and the optimal control strategy of the capacitor voltage balance is derived according to the configuration requirements of the two sub-modules. Finally, a hybrid MMC-based flexible DC transmission system is established in the PSCAD/EMTDC simulation environment, low DC voltage operation of the system are simulated to verify the correctness and effectiveness of the control strategy.
Construction Method of Backbone Grid Based on Survivability in Power Grid
Authors: Li Feng , Peng Hui-min , Li Wei , Yuan Hu-lin
Published: July 2019

Identifying backbone grid has great significance to the differential planning of power grid, which can improve the ability to withstand natural disasters effectively. In this paper, the problem of exploring backbone grid is formulated as a mixed integer nonlinear programming problem and the optimization target should balance the survivability and cost. Then, the problem of searching for backbone grid is solved with improved biogeography-based optimization algorithm, and several improvement strategies are employed to enhance the convergence rate and precision of the proposed method. The simulation verifies that the mathematical model can identify backbone grid appropriately and the improved algorithm can figure out backbone grid more effectively.
Analysis on Short Circuit Current Limiting Effect of Installing Small Reactance in 500kV Autotransformer’s Neutral-point
Authors: Fangfang Shi , Zeqing Zhao , Chao Yang , Zehui Zhang , Zhaohui Zhang , Mengmeng Sun , Meng Liu
Published: July 2019

For the condition that single-phase short circuit current exceeds three-phase short circuit current occurs on some of Shandong 500kV substations’ 220kV bus, this paper studies the principle of limiting 500kV autotransformer’s short circuit current by installing small reactance. Considering that installing small reactance at 500kV autotransformer’s neutral point influences the zero sequence circuit, this paper suggests to configure independent relay protection on small reactance which aims at supervision the short circuit current and improving reliability. Protection setting for neutral-grounding small reactance is proposed. Simulation results and protection setting software show the effect of limiting short circuit current by installing small neutral-point reactance.
Improved Control Strategy for Doubly-fed wind Turbines in Weak Synchronous Support Systems
Authors: Wang Weiyuan , Dou Fei , Yang Mengmeng , Huang Qinxin , Gao Yifan
Published: July 2019

When the wind power is sent as the interface by the line commutated converter, the vector-controlled doubly-fed wind turbine will be difficult to operate without power supply support, and it is impossible to send the wind power through the HVDC transmission system on a large scale. Future planned land-based wind power bases are becoming more remote and may not contain synchronous units. Therefore, it is extremely urgent to design a dual-feeder control strategy that can operate independently. In this paper, the control target of the doubly-fed turbine is changed to control the stator voltage and frequency. An improved control strategy of the doubly-fed turbine in the weak synchronous support system is proposed. The doubly-fed turbine will have the ability to send out through the line commutated converter. The simulation analysis of the wind power access weak synchronous support system sent by the HVDC transmission system is carried out. Under the natural wind disturbance, the sending end and the receiving end communication system disturbance, the doubly-fed turbine can quickly resume normal operation. With the effectiveness of this control strategy, the doubly-fed turbine can operate independently even if it loses its synchronous power supply.
Issues on Series-Parallel Circuits and their Drives in the Linear Machine for Heavy Mass Energy Storage System
Authors: Zhang Daming
Published: July 2019

An energy storage system using a linear machine for lifting heavy mass to convert its potential energy to/from electricity has the following advantages 1) Environment friendliness; 2) Long life span; 3) Potential lower cost-to-life span ratio which tests human-beings patience to see. Such kind of system has rotor or mover and stator structure. For simplicity, the stator can take windings spreading from the bottom to top of interleaved stator structure with windings wound around it. The stator windings are formed by multiple strands of aluminium conductors in parallel to reduce ohmic losses, leading to higher efficiency. The rotor or mover is formed by multiple fundamental units which are reinforced by stainless steel or other reinforcement, each unit consisting of flat copper conductor sandwiched between magnetic materials through insulators. The copper conductor in each unit is joined at terminals either in series or in parallel. In this paper research is on the issues of having proper number of series and parallel circuits.
Electromagnetic Transient Analysis of 750kV Four-circuit Transmission Line on the Same Tower
Authors: Lou Ying , Zha Zhipeng , He Huiwen , Li Zhenqiang
Published: July 2019

The ATP-EMTP program is used to calculate the power frequency overvoltage, open-phase power frequency resonant overvoltage, induced voltage and current, secondary arc current and recovery voltage, and switching overvoltage of 750kV four-circuit transmission line on the same tower. The study reveals that the configuration of four circuits on the same tower has little influence on the power frequency and switching overvoltage, but greatly influences the secondary arc current and recovery voltage, and induced voltage and current. Therefore, measures like installing high-voltage shunt reactor and neutral grounding reactor and line transposition are required. Also, the induced voltage and current ratings of earthing switch are proposed.
Fault Diagnosis Method of Circuit Breakers Based on Weighted Fuzzy Petri Nets
Authors: Zhang Xiaotong , Chen Qing , Sun Mengxuan , Huang Wudi , Gao Wangyuan
Published: July 2019

The maintenance and self-healing of circuit breakers are very difficult when the fault diagnosis results of circuit breakers cannot cover all kinds of fault causes. This paper proposes a method for comprehensively diagnosing circuit breaker faults. The method simulates the action process of circuit breakers based on weighted fuzzy Petri nets and makes it feasible to infer circuit breaker fault causes from different aspects. The model shows the action sequence of the circuit breaker by associating the control mechanism, the operating mechanism, the transmission mechanism and the contact part of the circuit breaker, and each part of it is described with the corresponding abnormal signals of the circuit breaker stored in the substation end. Specific fault reasons of the circuit breaker can be inferred by considering the action sequence and the relationship between the abnormal information and fault causes. The results for some test cases show that this method can obtain the diagnosis results covering various possible fault causes.
Calculation of Power Frequency Electric Field Around Ultra-High Voltage AC Transmission Lines
Authors: Zhang Yanyan , Wang Aihua , Yang Weiwei , Gao Nannan , Niu Lin , Li Pei , Huang Jinxin
Published: July 2019

Under the increasingly stringent situation of environmental protection management, it is necessary to research the distribution law of power frequency electric field around Ultra-High Voltage (UHV) AC transmission lines to provide technical basis for the design of transmission lines and the environmental impact assessment. Firstly the basic principle of equivalent charge method and its mathematical model are introduced in this paper. Then it is researched how to use equivalent charge method to analyze the electric field near the transmission lines. Based on the three-phase double-circuit overhead transmission line model, the influences of several factors on the power frequency electric field have been analyzed. These factors include the conductor-to-ground height, the phase sequence arrangement, the number of split conductors and the split spacing. Finally the frequency electric field of parallel UHV AC transmission lines is discussed. The results can provide reference for engineering design of UHV AC transmission lines.
Research on the Extensive Interconnect Characteristics of Power System
Authors: Wang Wei , He Yongjun , Chen Yufei , Zhu Sijia , Wang Ge
Published: July 2019

Based on the development law of electric energy, this paper puts forward the inevitability of the extensive interconnection of power system and their technical requirements. Firstly, this paper analyzes the law of energy development from the perspective of energy supply development, energy consumption development and energy transaction development. Secondly, based on China’s clean energy development pattern, the concept and significance of a new generation of power systems are widely interconnected. Finally, this paper proposes the technical requirements for the extensive interconnection of the power systems, respectively constructs the key technical systems of physical interconnection and information interconnection, and analyzes the development trends of related technologies.
Experimental studies of restoration of ball mill trunnion
Authors: Bondarenko YA , Bestuzheva OV , Sanina TM
Published: July 2019

The article deals with the analysis of experimental data on reconstruction of cement mill axles by the auxiliary machine at the place of operation. Based on the experimental research in repair the regression models of large-size equipment are developed, coefficients of equations of regression are defined. Importance of coefficients is estimated, and the adequacy of regression models is checked.
Obtaining computational models of mechanisms in geometric applications by example of mechanism of lifting signs of mold
Authors: Chepchurov M S , Zhukov E M , Sumskoy A M , Dudukalo D V
Published: July 2019

The article presents a solution to the problem of calculating and modeling the lifting mechanism of molds with the purpose of the reduction of the loading on the sliding bearings and verification of the working capacity of the mechanism as a whole. The calculation scheme is made for calculating the lifting mechanism of molds; the algorithm of operation of the mechanism is described. Mathematical modeling of the lever is conducted and the dimensions of separate links of the mechanism are calculated, the coordinates, trajectory of motion of the reference points of the mechanism are defined. A 3-D model of the lifting mechanism is executed; verification of the assembly of the model, of the operability of the mechanism is carried out as a whole.
Experimental testing of load kinematics in mixers with deformable chambers and vertical working tools
Authors: Lozovaya S Yu , Lozovoy N M , Uvarov V A , Ryadinskaya L V
Published: July 2019

Application of mixers with deformable chambers and vertical working tools has been justified as well as possibility to regulate particles translation inside the mixer chamber, which allows using maximal number of freedom action degrees on the material that provides necessary particle translation and necessary quality of the mixture. A kinematic model of a load point translation in the view of principles of continuous medium mechanics has been created. It has been determined that particles translate in cross- and longitudal sections along helix trajectories. The experimental studies of components particles translation in longitudal and cross sections with the use of models with transparent walls proved the choice of the theoretical model for the material point kinematics for determining forces and power.
Patterns of Drug and Alcohol Use and Injection Equipment Sharing Among People With Recent Injecting Drug Use or Receiving Opioid Agonist Treatment During and Following Hepatitis C Virus Treatment With Direct-acting Antiviral Therapies: An International Study
Authors: Artenie Andreea A , Cunningham Evan B , Dore Gregory J , Conway Brian , Dalgard Olav , Powis Jeff , Bruggmann Philip , Hellard Margaret , Cooper Curtis , Read Philip , Feld Jordan J , Hajarizadeh Behzad , Amin Janaki , Lacombe Karine , Stedman Catherine , Litwin Alain H , Marks Pip , Matthews Gail V , Quiene Sophie , Erratt Amanda , Bruneau Julie , Grebely Jason
Published: July 2019

Background

In many settings, recent or prior injection drug use remains a barrier to accessing direct-acting antiviral treatment (DAA) for hepatitis C virus (HCV) infection. We examined patterns of drug and alcohol use and injection equipment sharing among people with recent injecting drug use or receiving opioid agonist treatment (OAT) during and following DAA-based treatment.

Methods

SIMPLIFY and D3FEAT are phase 4 trials evaluating the efficacy of DAA among people with past 6-month injecting drug use or receiving OAT through a network of 25 international sites. Enrolled in 2016–2017, participants received sofosbuvir/velpatasvir (SIMPLIFY) or paritaprevir/ritonavir/dasabuvir/ombitasvir ± ribavirin (D3FEAT) for 12 weeks and completed behavioral questionnaires before, during, and up to 2 years posttreatment. The impact of time in HCV treatment and follow-up on longitudinally measured longitudinally measured behaviors was estimated using generalized estimating equations.

Results

At screening, of 190 participants (mean age, 47 years; 74% male), 62% reported any past-month injecting 16% past-month injection equipment sharing, and 61% current OAT. Median alcohol use was 2 (Alcohol Use Disorders Identification Test–Consumption; range, 1–12). During follow-up, opioid injecting (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.92–0.99) and sharing (OR, 0.87; 95% CI, 0.80–0.94) decreased, whereas no significant changes were observed for stimulant injecting (OR, 0.98; 95% CI, 0.94–1.02) or alcohol use (OR, 0.99; 95% CI, 0.95–1.04).

Conclusions

Injecting drug use and risk behaviors remained stable or decreased following DAA-based HCV treatment. Findings further support expanding HCV treatment to all, irrespective of injection drug use.

Clinical Trials Registration

SIMPLIFY, NCT02336139; D3FEAT, NCT02498015.