bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics modelling and analysis of a large-load swinging platform
Authors: Li Meng , Han Xianguo , Geng Ruihai
Published: December 2021

Swing platform is widely used to simulate the motion attitude of vehicles, ships and aircraft while carrying large loads. Aiming at the excessive driving force and output power of the driving parts caused by the large load swing platform, a new swing platform which can bear the large load was established. The swing platform is equipped with four spring branch chains between the moving platform and the static platform of the 6-UPS parallel mechanism, so as to offset the gravity of the large load and the inertia force of the large load in the process of motion, and the driving force of each branch chain is reduced. In this paper, the structure of the swing platform is introduced, and the dynamics of the swing platform is modeled using the Newton-Euler dynamics equation. Finally, the driving force of each branch chain of the swing platform is obtained by simulation of the dynamics of the swing platform. The simulation results show that the swing platform with four spring branch chains can effectively reduce the driving force of each branch chain compared with the traditional 6-UPS parallel mechanism swing platform.
Inspection method of combine assembly quality based on optimized VMD
Authors: Xuan Menghui , Zhao Sixia , Liu Mengnan , Xu Liyou , Chen Xiaoliang
Published: December 2021

Aiming at the problems of low assembly accuracy and difficult to detect assembly quality of combine, a method of combine assembly quality detection based on sparrow search algorithm (SSA) optimized variational mode decomposition (VMD) and particle swarm optimization (PSO) optimized least squares support vector machine (LSSVM) was proposed, Firstly, the sparrow search algorithm is used to obtain the optimal VMD decomposition modal parameter K and penalty factor α, then the combined vibration signal of combine harvester is decomposed into intrinsic modal components of different center frequencies by using the best parameter combination [K, α]. Finally, the feature vector is used as the input of LSSVM classifier to classify different fault features. The analysis results show that the classification accuracy of SSA-VMD joint feature extraction method is 99.5%, which is 17.5% and 9.5% higher than ensemble empirical mode decomposition (EEMD) and fixed parameter VMD, which verifies the superiority of this method in the detection of combine assembly quality.
Characteristics Analysis of Fluid-Structure Coupling Vibration of spray bar for High gap sprayer
Authors: Xing Mingming , Jia Yanli , He Caifeng , Wang Weijia , Li Yunjie , Geng Huiwen , Cheng Rui , Gong Wendi , Liu Xin
Published: December 2021

With the progressive improvement of the level of mechanization of agricultural production, the high-gap rod sprayer has gradually become an important component of agricultural production equipment. The stability of spray rod has an important influence on the life and operation quality of spray rod. Therefore, considering the stability of the spray rod of high gap sprayer, a fluid-solid coupling vibration simulation model of the spray rod of high gap sprayer is established in this paper. The influence of inlet velocity, inlet pressure, fluid density and fluid viscosity on the flow rate and dynamic pressure in the pipe was analyzed by fluent. The results show that the exit velocity increases with the increase of the inlet velocity, but when the velocity reaches a certain value, backflow occurs. With the increase of inlet pressure, the dynamic pressure increases, and the local energy loss and the energy loss along the path also increase. The velocity and dynamic pressure decrease with increasing density.
Numerical Analysis of Erosion Wear of Water with Particles in Elbows
Authors: Li Chaojie , Mao Yanqin , Wang Xiaoyue , Zhan Zhixing , Cai Liang
Published: December 2021

In this paper, the numerical analysis of erosion wear of water with particles in elbow is carried out based on fluent. The influence of different inlet velocity and bending angle on pipeline erosion, and the distribution of pressure field and velocity field in the pipeline are studied. The main conclusions are as follows: the erosion of elbow section is more serious than that of inlet section and outlet section of pipeline. With the increase of inlet velocity, the maximum erosion rate of elbow section gradually increases, and the maximum velocity and maximum pressure inside the elbow section also increase. When other conditions are certain, different bending angles make the elbow receive different erosion effects. When the bending angle is larger, the pipeline erosion rate is relatively more uniform. Study on erosion helps to reduce the impact of fluid on the wall and improve the safety and reliability of engineering.
Rotor Position Recognition Technology of Permanent Magnet Linear Synchronous Motor Based on Sliding Mode Observer
Authors: Wang Ruihao , Pan Xiaowei , Wang Qihui , Huo Junling , Wu Hongxing
Published: December 2021

Position sensorless control system of permanent magnet linear synchronous motor has some advantages: simple structure, easy maintenance, high efficiency, good speed performance, etc. This paper designed a position sensorless control system of permanent magnet linear synchronous motor based on sliding mode observer, namely taking advantage of a sensorless algorithm to estimate the pole position and speed. Firstly, the principle of sliding mode control and basic conditions which need to achieve are analyzed. And then, a sliding mode observer of the permanent magnet linear synchronous motor sensorless control system is designed. The related simulation model is built to study the effect of sliding mode observer for rotor position accuracy. The simulation model is implemented to build models of permanent magnet linear synchronous motor vector control system based on sliding mode observer and simulate the control performance of position sensorless control. In the last part, the feasibility of the design scheme is verified by analysis of simulation results.
Multi-quality Index Optimization of Injectionof injection Compression Process Parameters Based on Grey Robustness
Authors: Zhu Junjie , Huang Wenhan , Qiu Zhiwen
Published: December 2021

Aiming at the balance optimization of multiple mass indexes, such as sink marks, warpage and residual stress in the injection compression molding process of optical products, from the perspective of robust design, the experiment of injection compression processing of wedge-shaped light guide plate with five factors and four levels was designed by orthogonal experiment method. The optimal combination of process parameters, the order of influence and the trend of change were obtained by S/N analysis. Finally, the grey relational theory was used to transform the multi-quality index optimization problem into the single objective optimization of grey relational degree, and the optimal process parameter combination considering multiple quality indexes were obtained. Compared with before optimization, each quality index decreased by 23.89%, 8.87% and 24.68% respectively. The research shows that the optimization technology based on grey robustness can effectively solve the problem of balance optimization among multiple mass indexes, and can realize the overall optimization of injection compression process parameters.
Research on system modeling and motion control simulation of automatic power trowel
Authors: Xu Hao , Zhu Yutian , Chen Mo , Liu Zhao
Published: December 2021

Aiming at the problems that the existing control researches on the power trowel are limited to the analysis of the motion principle and the open-loop control of some mechanisms, taking a hydraulically-driven ride-on power trowel as the research object, the closed-loop control method of the point-to-point motion of the power trowel is studied. After analyzing the motion principle of the power trowel, based on the assumption of elastic deformation of concrete, the dynamic model of a single trowel is established, and the relationship between the driving force, driving moment and hydraulic moment, velocity, and angular velocity of the trowel is obtained. The whole machine motion equation of the power trowel is deduced, the point-to-point state feedback control algorithm of the power trowel is studied, and a simulation model is built to verify the accuracy of the system model of the power trowel and the effectiveness of the control algorithm. This research can provide reference for the control method design of other complex motions of the power trowel.
Gaussian Process based Remaining useful life Prediction for Electric Energy Metering Equipment
Authors: Li Ning , Duan Junfeng , Ma Jun , Qiu Wei , Zhang Wei , Teng Zhaosheng
Published: December 2021

Electric energy metering equipment (EEME) will fail in advance not as designed running in extreme environments. A multi-kernel Gaussian process regression model using measurement error data to perceive remaining useful life (RUL) for EEME is proposed. Firstly, the gauss kernel and periodic kernel are used to match the health index trend of EEME under a variety of typical environmental stresses. Furthermore, the Bayesian method and Monte Carlo Markov chain method are used to solve the model, and the Weibull distribution is used to fit the posterior trajectory to get the probability density estimation of the RUL.
An Optimized Design of an Electric Vehicle Wireless Charging Coupling Coil
Authors: Xie Wei , Chen Qi-gong , Lei Shou-zhong
Published: December 2021

With the development of electric vehicle wireless charging technology, the transmission power and transmission efficiency of electric vehicle wireless charging system have become the focus of current research. The transmission power and efficiency of wireless charging system largely depend on the energy loss of two resonant coupling coils. The energy loss is mainly related to the structural parameters of the coupling coil and the coupling coefficient of the two coils. On this basis, the structure of the coupling coil is designed and optimized by using the finite element analysis software Maxwell, and a new combined transmitting coil structure is designed. Experiments and verification show that the coil design meets the requirements of transmission efficiency, which can provide a reference for the design of wireless charging coil of electric vehicle in the future.
Static and dynamic performance analysis of scissor seat of combine harvester
Authors: Song Hao , Xu Liyou , Chen Xiaoliang , Wei Weizhen , Liu Kui
Published: December 2021

This paper takes the scissor type seat of a domestic combine harvester as the research object, uses CATIA software to carry out three-dimensional modeling of the seat, and then imports the seat model into ANSYS Workbench software for static analysis and modal analysis, so as to judge whether the scissor type seat of the combine harvester meets the design requirements. The results of static analysis show that the maximum stress of the seat under the two different loads is less than the yield strength of the material, and the overall strength of the seat meets the design requirements. The modal analysis results show that the first six natural frequencies of the seat completely avoid the sensitive frequencies of the human body, which basically guarantees the working comfort of the driver. This study provides a theoretical basis for the structural design and optimization of combine seat.
Thermodynamic properties of fission products in liquid bismuth
Authors: Ding Guohua , Liang Limeng
Published: December 2021

The thermodynamic properties of fission products in molten salt and liquid metal have a great influence on the disposal of nuclear waste in the nuclear fuel cycle industrial system. This paper attempts to extract useful thermodynamic information from the only few experimental activities of lanthanides (Ce, Pr, La) in liquid Bi at different temperatures. The molecular interaction volume model (MIVM) was adopted to model and predict some temperature-dependent thermodynamic functions, including activity, infinite dilute activity coefficient, and molar excess Gibbs energy. The minor average of

Δ

G
¯

error indicated that assuming εji
− εii
is a constant is reasonable. On this basis, the natural logarithm of the interaction coefficients and the natural logarithm of the infinite dilute activity coefficient of lanthanides (Ce, Pr, La) in the Bi-based metal melt, these two parameters, show the linear relationship with the reciprocal of temperature. The reasonable agreement of the modeled thermodynamic parameters with the existing experimental data verified that the MIVM is quite convenient and reliable, which can provide guidance for separating fission products from molten salt reactors.
Ming-style chair parts and its group technology application research
Authors: Wang Yufan , Ren Yi , Yang Xinyan , Zhang Zhongfeng
Published: December 2021

In order to apply the group technology to the production of Ming style furniture, enhance the ability of enterprises to cope with the production of small-batch, multi-variety furniture, this article will take Ming-style chair furniture as an example to make a reasonable division of its parts. The types of Ming-style chair parts are combed, the characteristic information of each component is extracted and the joint mode of mortise and tenon between two parts is summarized. In this way, the process of each mortise and tenon structure is summarized, and the correspondence between mortise and tenon structure and the machinery is established. According to this method, the Ming-style chair parts are summarized and classified into 211 kinds. Based on the similarity of parts processing machinery, all parts of the Ming-style chairs are classified into groups by fuzzy clustering algorithm and MATLAB software calculation. The purpose of this article is to provide a divisional idea for the pre-part classification preparation of Ming-style chair parts in groups for the part family.
Research on the dynamic characteristics of the acquisition mechanism of the oscillating flapping wing wave energy power generation device based on the bond graph
Authors: Fang Zifan , Wang Jiajia , Xiong Fei , Xie Xueyuan
Published: December 2021

Taking the acquisition mechanism of the oscillating flapping-wing wave energy power generation device as the research object, the design of the acquisition mechanism, the bond graph model of the acquisition mechanism and the dynamic characteristics are studied. According to the working principle of the acquisition mechanism of the oscillating flapping wing wave energy power generation device, the bond graph model and the state space equation of the acquisition mechanism are established. Based on the bond graph theory, the AMESim software is used for simulation analysis to verify the correctness of the bond graph model of the acquisition mechanism. The research results show that the designed oscillating flapping wing wave energy generation device acquisition mechanism responds quickly and stably, and the bond graph model basically matches the real system. The research process provides an effective reference for the development of the acquisition mechanism of the oscillating flapping wing wave energy power generation device.
Modeling and analysis of the characteristics of SiC MOSFET
Authors: Qiu Guoqing , Jiang Kedi , Xu Shengyou , Yang Xin , Wang Wei
Published: December 2021

Although the superior performance of SiC MOSFET devices has beenvalidated by many studies, it is necessary to overcome many technical bottlenecks to make SiC MOSFET gradually replace Si-based power devices into the mainstream. In view of the current situation where the performance of SiC MOSFETs in power conversion devices cannot be evaluated well at this stage, it is necessary to carry out fine modeling of SiC MOSFETs and establish accurate simulation models. In this paper, the powerful mathematical processing capability and rich modules of Matlab/Simulink are used to build a SiC MOSFET model, and then the product data sheet is compared with the fitted data. The results show that the switching simulation waveforms are in general agreement with the data sheet waveforms, and the error is less than 7%. Verifing the accuracy of the model and reducing the difficulty of modeling, it provides a new idea for establishing the circuit simulation model of SiC MOSFET in Matlab/Simulink.
Design and research on the simulation platform of Oscillating Flapping-Wing Wave Energy Converter based on AMESim
Authors: Fang Zifan , Xie Xueyuan , Wang Jiajia , Xiong Fei
Published: December 2021

It is a stochastic dynamic process for conversion of wave energy, which includes the coupling of multiphysics. Energy conversion efficiency and stable output are important objectives. In order to explore the mechanism of wave energy efficient conversion, a wave energy generation scheme of oscillating-flapping wing was proposed. Taking the conversion system of wave power generation device as the research object, the mechanical-hydraulic-circuit simulation platform of the system is established by the software AMESim. The proposed scheme is tested and verified. The results show that the wave energy conversion system can effectively convert wave energy, realize the stable output of electric energy and store it in the battery pack, which provides a theoretical basis for the development of wave energy generation converter of oscillating-flapping wing.
Design and research of hydraulic conversion system of wave energy generating device
Authors: Fang Zifan , Xiong Fei , Xie Xueyuan , Wang Jiajia
Published: December 2021

Taking the hydraulic conversion system of the oscillating flapping-wing wave energy power generation device as the research object, a hydraulic conversion system is designed to convert wave energy into usable mechanical energy. Based on the principle of high-efficiency collection of wave energy and stable output of the hydraulic conversion system, the composition of the hydraulic conversion system and the parameters of each component are determined. According to different sea conditions, the pre-charge pressure of the accumulator is adjusted to keep the pressure of the high and low pipelines of the hydraulic system stable, and the mechanical energy is stably output through the hydraulic motor. The AMESim simulation platform is used to build the model of acquisition mechanism and hydraulic conversion system, simulate the motion response of acquisition mechanism under actual sea conditions as the system input, and analyze the effectiveness and output stability of hydraulic conversion system. The results verify that the designed hydraulic conversion system can achieve efficient collection of wave energy. The research results have laid a theoretical foundation for the development and research of wave energy power generation devices.
Vibration Characteristics Research of Sandwich Structure with Octet-truss Lattice Core
Authors: Wei Nan , Ye Hongling , Zhang Xing , Li Jicheng , Yuan Boshuai
Published: December 2021

Lattice sandwich beams are often subjected to vibrations when they are used. The aim of this study was to explore the vibration characteristics of the octet-truss lattice core sandwich beam by translating discrete octet-truss core to the continuous homogenization material. The natural frequencies of which are obtained by theoretical calculation and numerical simulation. The theoretical solutions are in good agreement with the numerical results. It demonstrates that the theoretical approach is effective to compute the natural frequency. Furthermore, the influences of truss member radius and thin sheets ply on the natural frequencies are also discussed. The outcomes indicate that the octet-truss lattice core sandwich beam’s natural frequencies are controlled via selecting the appropriate truss member radius and the face sheets thickness.
Crack Propagation Analysis of Damaged Solid Propellant under Impact Overload
Authors: Hou Xiao-ming , Fan Le , Yu Cun-gui , Zhong Jian-lin
Published: December 2021

The ammunition safety problem is particularly prominent when the storage and transportation launch box is airdropped and landed. A safety evaluation method of rocket air drop based on propellant damage evaluation is proposed. Based on the theory of fracture mechanics and the evaluation method of structural integrity of rocket engine, established a local finite element model of rocket engine with initial damage, the crack propagation analysis is carried out by using the propagation finite element method (XFEM). The results show that when the landing impact overload is 30g (25ms) that the airdrop equipment should be able to withstand, the modified double base propellant has produced the phenomenon of crack instability propagation. When the initial crack direction and load direction are 120 °, the propagation is the most serious and there are safety problems; when the solid propellant is airdropped, it is necessary to increase the buffer to reduce the overload.
Design and research of a center adjustment mechanism based on missile ground test stand
Authors: Ren Gao-lin , Zhang Xue-wei , Wei Qiang , Lei Chen-hui , Zhang Zhen , Qi Qiang-qiang , Gao Yue-qi
Published: December 2021

For a missile ground test stand that requires a lot of core installation, such as the inner and outer labyrinth centering installation. There are some problems in the installation process, such as complex installation process, difficult adjustment, long installation time, poor positioning accuracy and so on. This paper takes the inner and outer labyrinth centering installation as an example, through non-standard structure selection and processing, designed a set of centering adjustment mechanism, through the field installation comparison, it is concluded that the new centering adjustment mechanism has the advantages of high positioning accuracy, simple operation, greatly saving working time, quick and simple adjustment, etc. The new centripetal adjustment mechanism is also simple, efficient and cost saving for other tasks that need centripetal adjustment on missile ground test bed. Its design and research have high engineering practical significance.
High Torque Density Permanent Magnet Brake
Authors: Yue Qiang , Qian Hao
Published: December 2021

As the braking device of the aircraft electromechanical actuation system, the brake is a vital link in the aircraft attitude change or function adjustment. Among them, the permanent magnet brake has attracted extensive attention in the field of aerospace technology because of its advantages of low energy consumption and high reliability. At present, the domestic permanent magnet brake is heavy and the braking torque density is generally low, which limits its further development in the field of aerospace. In order to improve the braking torque density of permanent magnet brake, this paper proposes a research method of high torque density permanent magnet brake is proposed. By establishing the magnetic circuit structure of the permanent magnet brake, the relationship between the external characteristics of the permanent magnet brake and the design parameters is determined, and then the performance parameters of the permanent magnet brake are simulated and verified by using the finite element simulation software. Finally, through the physical test, the results show that this method can effectively improve the braking torque density.
Study on Improving the Sealing Reliability of Fluid Connector
Authors: Qiao Jing , Jin Guangzai , Li Guanghui , Wang Yu , Wang Xiangling
Published: December 2021

Aiming at the problem of sealing reliability of fluid connector products commonly used in hydraulic system, this paper studies the static seal and the sliding seal. The factors affecting the sealing such as spring force, sealing ring and life of spring are considered one by one and the sealing effect is teseted. The results showed that improved fluid connector can ensure that the hydraulic system is in the state of not even air intake or oil leakage while connecting and disconnecting at any time. The connector has been successfully applied to a certain model of launch vehicle.
Horizontal position reconstruction in PandaX-II
Authors: Zhang D. , Tan A. , Abdukerim A. , Chen W. , Chen X. , Chen Y. , Cheng C. , Cui X. , Fan Y. , Fang D. , Fu C. , Fu M. , Geng L. , Giboni K. , Gu L. , Guo X. , Han K. , He C. , He S. , Huang D. , Huang Y. , Huang Y. , Huang Z. , Ji X. , Ju Y. , Li S. , Lin Q. , Liu H. , Liu J. , Liu L. , Lu X. , Ma W. , Ma Y. , Mao Y. , Meng Y. , Namwongsa P. , Ni K. , Ning J. , Ning X. , Ren X. , Shaheed N. , Shang C. , Shen G. , Si L. , Wang A. , Wang H. , Wang M. , Wang Q. , Wang S. , Wang W. , Wang X. , Wang Z. , Wu M. , Wu S. , Wu W. , Xia J. , Xiao M. , Xiao X. , Xie P. , Yan B. , Yang J. , Yang Y. , Yu C. , Yuan J. , Yuan Y. , Zeng X. , Zhang T. , Zhao L. , Zheng Q. , Zhou J. , Zhou N. , Zhou X.
Published: December 2021

Dual-phase noble-gas time projection chambers (TPCs) have
improved the sensitivities for dark matter direct search in past
decades. The capability of TPCs to reconstruct 3-D vertexes of keV
scale recoilings is one of the most advantageous features. In this
work, we develop two horizontal position reconstruction algorithms
for the PandaX-II dark matter search experiment using the dual-phase
liquid xenon TPC. Both algorithms are optimized by the 83mKr
calibration events and use photon distribution of ionization signals
among photomultiplier tubes to infer the positions. According to the
events coming from the gate electrode, the uncertainties in the
horizontal positions are 3.4 mm (3.9 mm) in the analytical
(simulation-based) algorithm for an ionization signal with several
thousand photon electrons in the center of the TPC.
Medipix3 proton and carbon ion measurements across full energy ranges and at clinical flux rates in MedAustron IR1
Authors: Bal N.J.S. , Schmitzer C.S. , De Franco A. , Enke S.
Published: December 2021

The Medipix3, a hybrid pixel detector with a silicon sensor, has been evaluated as a beam instrumentation device with proton and carbon ion measurements in the non-clinical research room (IR1) of MedAustron Ion Therapy Center. Protons energies are varied from 62.4 to 800 MeV with 104 to 108 protons per second impinging on the detector surface. For carbon ions, energies are varied from 120 to 400 MeV/amu with 107 to 108 carbon ions per second. Measurements include simultaneous high resolution, beam profile and beam intensity with various beam parameters at up to 1000 FPS (frames per second), count rate linearity and an assessment of radiation damage after the measurement day using an x-ray tube to provide a homogeneous radiation measurement. The count rate linearity is found to be linear within the uncertainties (dominated by accelerator related sources due to special setup) for the measurements without degraders. Various frequency components are identified within the beam intensity over time firstly including 49.98 Hz with standard deviation, σ = 0.29, secondly 30.55 Hz σ = 0.55 and thirdly 252.51 Hz σ = 0.83. A direct correlation between the number of zero counting and noisy pixels is observed in the measurements with the highest flux. No conclusive evidence of long term radiation damage was found as a result of these measurements over one day.
Evaluation of the VOC pollution pattern and emission characteristics during the Beijing resurgence of COVID-19 in summer 2020 based on the measurement of PTR-ToF-MS
Authors: Zhang Zhining , Man Hanyang , Duan Fengkui , Lv Zhaofeng , Zheng Songxin , Zhao Junchao , Huang Feifan , Luo Zhenyu , He Kebin , Liu Huan
Published: December 2021

A second wave of coronavirus disease 2019 (COVID-19) infections emerged in Beijing in summer 2020, which provided an opportunity to explore the response of air pollution to reduced human activity. Proton-transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) coupled with positive matrix factorization (PMF) source apportionment were applied to evaluate the pollution pattern and capture the detailed dynamic emission characteristics of volatile organic compounds (VOCs) during the representative period, with the occurrence of O3 pollution episodes and the Beijing resurgence of COVID-19. The level of anthropogenic VOC was lower than during the same period in previous years due to the pandemic and emission reduction measures. More than two thirds of the days during the observation period were identified as high-O3 days and VOCs exhibited higher mixing ratios and faster consumption rates in the daytime on high-O3 days. The identified VOC emission sources and the corresponding contributions during the whole observation period included: vehicle + fuel (12.41 ± 9.43%), industrial process (9.40 ± 8.65%), solvent usage (19.58 ± 13.46%), biogenic (6.03 ± 5.40%), background + long-lived (5.62 ± 11.37%), and two groups of oxygenated VOC (OVOC) factors (primary emission and secondary formation, 26.14 ± 15.20% and 20.84 ± 14.0%, respectively). Refined dynamic source apportionment results show that the ‘stay at home’ tendency led to decreased emission (−34.47 ± 1.90%) and a weakened morning peak of vehicle + fuel during the Beijing resurgence. However, a growing emission of primary OVOCs (+51.10 ± 8.28%) with similar diurnal variation was observed in the new outbreak and afterwards, which might be related to the enhanced usage of products intended to clean and disinfect. The present study illustrated that more stringent VOC reduction measures towards pandemic products should be carried out to achieve the balanced emission abatement of NO
x
and VOC when adhering to regular epidemic prevention and control measures.
Distinct roles of land cover in regulating spatial variabilities of temperature responses to radiative effects of aerosols and clouds
Authors: Wei Linyi , Wang Yong , Liu Shu , Zhang Guang J , Wang Bin
Published: December 2021

Surface temperature responses to radiative perturbations due to aerosols and clouds are complicated by the land surface properties. To disentangle these complexities, this study, from a terrestrial surface energy budget perspective, isolates the underlying biophysical processes from the instantaneous radiative effects of aerosols and clouds on surface temperature using the National Center for Atmospheric Research Community Earth System Model version 1.2.1. It is found that in comparison with the global heterogeneous distributions of instantaneous radiative perturbations at the surface induced by aerosols and clouds, the spatial variations of the corresponding surface temperature responses to aerosol direct radiative effects (DRE) during the daytime and cloud radiative effects (CRE) during the nighttime are amplified. It is because of the consistent global distribution of the local surface climate sensitivity (a function of land cover properties such as surface roughness and Bowen ratio) with those of daytime DRE and nighttime CRE. By applying identical anthropogenic aerosol and precursor emissions over eight major past, present and projected future anthropogenic aerosol emitting regions (i.e. Brazil, China, East Africa, India, Indonesia, South Africa, United States and Western Europe), surface temperature responses to aerosol radiative cooling in the daytime and cloud radiative warming in the nighttime over these regions positively regulated by local surface climate sensitivities are prominent.
Crossover scaling functions in the asymmetric avalanche process
Authors: Trofimova A A , Povolotsky A M
Published: December 2021

We consider the particle current in the asymmetric avalanche process on a ring. It is known to exhibit a transition from the intermittent to continuous flow at the critical density of particles. The exact expressions for the first two scaled cumulants of the particle current are obtained in the large time limit t → ∞ via the Bethe ansatz and a perturbative solution of the TQ-equation. The results are presented in an integral form suitable for the asymptotic analysis in the large system size limit N → ∞. In this limit the first cumulant, the average current per site or the average velocity of the associated interface, is asymptotically finite below the critical density and grows linearly and exponentially times power law prefactor at the critical density and above, respectively. The scaled second cumulant per site, i.e. the diffusion coefficient or the scaled variance of the associated interface height, shows the O(N
−1/2) decay expected for models in the Kardar–Parisi–Zhang universality class below the critical density, while it is growing as O(N
3/2) and exponentially times power law prefactor at the critical point and above. Also, we identify the crossover regime and obtain the scaling functions for the uniform asymptotics unifying the three regimes. These functions are compared to the scaling functions describing crossover of the cumulants of the avalanche size, obtained as statistics of the first return area under the time space trajectory of the Vasicek random process.
Resonator method for measuring the polarizability of small components of composite materials
Authors: Dorofeev I O , Dunaevskiy G E , Shansho A
Published: December 2021

The creation of new composite materials with specified radio-frequency properties is often carried out using small-sized inclusions, while the polarizability parameters of these small bodies in electric and magnetic fields play a significant role. The paper considers the possibility of measuring the polarizability of small components of the composite in an open quasi-optical resonator. It is shown that the values of the electric and magnetic polarizability of small particles can be estimated from the shifts of the resonant frequencies that arise when a small scatterer is placed in the resonator.
Improving the shielding efficiency and weight reducing of the radio-absorbing coating by adding a matching layer
Authors: Dorozhkin K V , Suslyaev V I , Kazmina O V , Matyskin K E , Yu Korovin E
Published: December 2021

The spectra of complex permittivity of the composites consisting of rubber silicone compound and electroconductive fine-dispersed silver-coated copper powder were investigated. To enhance the effectiveness of the composite interaction with microwaves and reduction of its weight and dimensions characteristics two and three-layer constructions were produced. Matching layers were made of foam glass material with addition SiC and Fe3O4.
Electromagnetic characteristics of materials based on ultrafine hexaferrite powders
Authors: Gladkov YuN , Kachalov AS , Korovyn EYu , Pavlova AA
Published: December 2021

The electromagnetic characteristics of composite materials based on nanosized powders of W-type hexaferrites are considered in the article. It is shown that not only the composition, but also the mechanical treatment affects the electromagnetic parameters. This article presents the frequency dependence of the complex magnetic and dielectric permittivity of a system of W-type hexafferites. The studies were carried out on a universal wide-band measuring complex based on the Agilent PNA-X N4257A Vector Network Analyzer. The results are presented in the frequency range from 2 to 14 GHz.
Towards structured SPP manipulation of light at the nanoscale
Authors: Minin I V , Liu C-Y , Minin O V
Published: December 2021

Surface plasmon photonics is a rapidly developing area of physics, optics, and nanotechnology. The unique ability of meso- and nano-structures to manipulate light in the subwavelength range down to nanoscale volumes stimulated their use in a vast research endeavours. The investigations are driven by interests in both fundamental and practical applications aspects where plasmonic light concentrators elegantly interface mesoscale dielectric structure with thin metal films. The effects of a photonic nanojet and a photonic hook, discovered by Minins, have been studied in sufficient detail in the literature, but only recently have they been able to be confirmed experimentally for low-dimensional systems – in-plane surface plasmon waves. The nature of these phenomenas lies in the dispersion of the phase velocity of waves inside the dielectric structure, which leads to constructive interference of the transmitted, diffracted, and near-field waves. Our results set the grounds for in-plane plasmonic wavelength scaled optics with unprecedented control of the energy flow at the nanoscale, and shown a way toward realizing the densely packed optical elements needed for future plasmonic and optical devices.
Structured plasmonic beam: in-plane manipulation of light at the nanoscale
Authors: Minin I V , Minin O V
Published: December 2021

The brief review on recent approaches on the formation of a new class of subwavelength scale localized structured surface plasmon polaritons (SPP) beams is discussed. For the Janus-like particle (including the geometrically symmetric particles with different dielectrics) the morphology of the field localization area and its properties depends on the particle shape and material. Plasmonic hook (PH) beam does not propagate along straight line but instead follow curved self-bending trajectory. Wavefront analysis behind of such symmetric and asymmetric mesoscale rectangle structure reveals that the unequal phase of the transmitted plane wave results in the irregularly concave deformation of the wavefront inside the dielectric which later leads to creation of the PH. Such dielectric structures placed on metal film enable the realization of new ultracompact wavelength-selective and wavelength-scaled in-plane nanophotonic components. SPP have potential to overcome the constrains on the speed of modern digital integrated devices limitation due to the metallic interconnects and increase the operating speed of future digital circuits.
Tunable microstrip liquid crystals patch antennas
Authors: Romanov N A , Chimytov T A , Nomoev A V , Ch Khartaeva E , Gurvitz E A
Published: December 2021

A patch antenna based on liquid crystals for the5G GHz range was simulated. The variation of the antenna frequency range after doping magnetic nanoparticles was verified. The high-frequency patch antenna parameters are calculated considering the dependence of the reflectivity of the antenna 11 on the dielectric anisotropy, gain, directivity and phase shift. The ability to control the frequency range of the patch antenna is shown. The phase distributions were demonstrated for 5CB crystals with a slight variation in the dielectric constant tensor and crystals with magnetic permeability.
Synthesis of textured films of hexagonal barium ferrite on Al2O3/Si3N4 amorphous structure
Authors: Mironovich A. Yu. , Kostishyn V.G. , Isaev I.M.
Published: December 2021

In this work structural studies of BaFe12O19/Al2O3/Si3N4 thin films with different thicknesses of aluminum oxide and silicon nitride are represented. It is shown that barium hexaferrite crystallizes on the amorphous surface of aluminum oxide with spontaneously formed (00l) uniaxial texture. Microstructural differences in BaFe12O19 films were observed with varying of the thickness of amorphous sublayers, which is explained by the effect of mechanical stress.
Structural Optimization of Road Fully Enclosed Sound Barrier Based on Three-Dimensional Finite Element Analysis
Authors: jingqiang Yang , dewei Din , zhimian Yang
Published: December 2021

With the help of the finite element analysis software ANSYS, this paper establishes a finite element model of a fully enclosed sound barrier of elevated road, calculating and analyzing the stress of supporting structure under different working conditions, checking the strength, stiffness and stability of the structure under the most unfavorable working condition. Finally we optimize the structure according to its characteristics.
An Intelligent Bearing Fault Diagnosis Method Based on SF-SVM
Authors: Qiu Bao’an , Sun Pan , Li Lili
Published: December 2021

Rolling bearing, as a key component of rotating machinery, its health status directly determines the stability and reliability of the whole machine. The research on its intelligent diagnosis method has important engineering value and academic significance. However, due to actual engineering conditions, the types of bearing failures and the amount of data are limited. Aiming at the difficulty of extracting and selecting bearing vibration features under limited sample constraints, this pa-per proposes an intelligent fault diagnosis method of SF-SVM. On the basis of the short-time Fourier change, the L2 regularized sparse filter is used to extract the unsupervised feature of the bearing vibration time-frequency map. After obtaining the typical features of the bearing, the support vector machine is used for diagnosis.
Corrosion behavior and electrochemical corrosion of a high manganese steel in simulated marine splash zone
Authors: Yan Xinyong , Yan Ling , Kang Shumei , Qi Xiangyu , Xu Meiling , Zhang Peng
Published: December 2021

The corrosion behavior of a high manganese steel in simulated marine splash zone environment was studied by dry-wet cyclic corrosion experiment and electrochemical experiment. Corrosion kinetics, composition, surface morphology, cross-section morphology, element distribution, valence state, polarization curve and electrochemical impedance spectroscopy were analyzed with the aim of characterizing the characteristics of corrosion product films. The results show that in chloride-containing environment, in the initial corrosion products, Mn oxides with porous structure lead to higher corrosion rate. As corrosion extends, the formation of alloy element oxides in corrosion products changes the corrosion properties of rust layers at different stages. Mo oxides form a stable passivation film, which reduces the influence of chloride ion on corrosion. Ni oxides in the inner rust layer facilitate the transformation of goethite, and Cr oxides in the outer rust layer increase the densification of the rust layer. The stability and compactness of Fe3O4, α-FeOOH and FeCr2O4 in the later corrosion products inhibit the corrosion action of manganese iron oxides and slow down the corrosion rate. With the corrosion durations, the corrosion current density of the sample with the corrosion product film first increases and then decreases, and the corrosion potential first moves negative and then shifts in a positive direction subsequently, indicating that the protective effect of the corrosion product film is gradually significant.
Road performance analysis of cement stabilized coal gangue mixture
Authors: Li Zhenxia , Guo Tengteng , Chen Yuanzhao , Zhao Xu , Chen Yanyan , Yang Xiao , Wang Jing
Published: December 2021

In order to solve the environmental pollution of coal gangue and the shortage of aggregate resources in road engineering, waste coal gangue is used as road base material instead of natural stone materials. Through physical, mechanical, chemical and activity tests of coal gangue aggregate, the optimal gradation composition of unconfined compressive strength was determined. Through unconfined compressive strength, indirect tensile strength, flexural tensile strength, freeze-thaw and dry shrinkage tests, the influence of cement content on road performance of cement stabilized coal gangue mixture was studied. By means of SEM, ICP AES, XRD and optical digital microscope, the difference between spontaneous combustion coal gangue and Unspontaneous combustion coal gangue was analyzed, the microstructure of cement stabilized coal gangue mixture was characterized, and the strength formation mechanism of mixture was explored. The results show that Spontaneous combustion coal gangue has higher activity than Unspontaneous combustion coal gangue. Based on the selected optimal allocation (BNS:SNS:SSC = 71.26:9.41:18.8). The mixture of 4% cement dosage can not only meet the requirement of early strength 4.16 MPa, but also show an efficient strength growth rate of 36.10%, showing the optimum mechanical properties. The total shrinkage coefficient of cement stabilized coal gangue mixture with 4% cement dosage is 1.12 × 10−2, which shows that the dry shrinkage resistance is the best. With the increase of time, hydration degree is gradually deepened, and gelled substance is more tightly bonded to aggregates. There is no obvious gap between aggregates, and the integrity of the mixture is enhanced, which can show better road performance. Ca (OH)2, a cement hydration product in cement stabilized coal gangue mixture, takes place pozzolana reaction with active SiO2 and Al2O3 in coal gangue to produce gismondine, which is beneficial to the global strength and the bond quality of the mixture.
Selectively dry etched of p-GaN/InAlN heterostructures using BCI3-based plasma for normally-off HEMT technology
Authors: Toprak A , Yılmaz D , Özbay E
Published: December 2021

In this paper, an alternative selective dry etching of p-GaN over InAlN was studied as a function of the ICP source powers, RF chuck powers and process pressures by using inductively coupled plasma reactive ion etching (ICP RIE) system. A recipe using only BCI3-based plasma with a resulting selectivity 13.5 for p-GaN in respect to InAlN was demonstrated. Surface roughness measurements depending on the etching time was performed by atomic force microscope (AFM) measurement and showed that a smooth etched surface with the root-mean-square roughness of 0.45 nm for p-GaN and 0.37 nm for InAlN were achieved. Normally-off p-GaN/InAlN HEMT devices were fabricated and tested by using the BCI3-based plasma we developed.
Synthesis of TiB2-Ni3B nanocomposite coating by DC magnetron sputtering for corrosion-erosion protection
Authors: Hernández Jorge Morales , García José Manuel Juárez , Hernández Héctor Herrera , Dorantes Rosales Héctor J , Herrera Basurto Raul
Published: December 2021

Significant contribution on corrosion-erosion resistance of Ni3B-TiB2 nanocomposite coating of 1 μm of thickness, deposited by DC magnetron Sputtering on stainless steel 304 substrates was studied. Nickel phase (γ Ni) plus Ni3B-TiB2 phases were synthesized previously by Mechanical Alloying (MA). Solid cathode (76.2 mm of diameter and 3 mm of thickness) used to grow thin films was manufactured with the alloyed powders, applying a uniaxial load of 70 MPa at room temperature and sintered at 900 °C for two hours. Microstructure and mechanical properties of the coatings were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nanoindentation, and wear test with a ball-on-disc tribometer. Compact coating of Ni3B-TiB2 with a microstructure of prismatic crystals after annealing treatment, showing a uniform coating with good adherence and low friction coefficient of 0.5, correlated with a low roughness of Ra ≈ 0.0439 ± 0.0069 μm. The average hardness of 537.4 HV (5265.0 MPa) and wear coefficient at room temperature of 2.552E-10 m2N−1 correspond with medium-hard phases with an elastic-plastic behavior suitable for fatigue applications. Geothermal fluid modified was synthesized in the lab with NaCl/Na2SO4 to evaluate the corrosion resistance of the films in a standard three electrodes cell, characterizing a corrosion rate of 0.0008 and 0.001 mm*year−1 at 25 and 80 °C respectively during 86.4 ks (24 h) of exposition; showing a resistive coating without corrosion products and with good response to the geothermal environment.