bluuebunny/crossref_metadata_2025 huggingface dataset:
Antiferromagnetic skyrmion-based logic gates controlled by electric currents and fields
Authors: Liang Xue , Xia Jing , Zhang Xichao , Ezawa Motohiko , Tretiakov Oleg A. , Liu Xiaoxi , Qiu Lei , Zhao Guoping , Zhou Yan
Published: August 2021

Antiferromagnets are promising materials for future spintronic applications due to their unique properties including zero stray fields, robustness vs external magnetic fields, and ultrafast dynamics, which have attracted extensive interest in recent years. In this work, we investigate the dynamics of isolated skyrmions in an antiferromagnetic nanotrack with a voltage-gated region. It is found that the skyrmion can be jointly controlled by the driving current and the voltage-controlled magnetic anisotropy gradient. We further propose a design of logic computing gates based on the manipulation of antiferromagnetic skyrmions, which is numerically realized combining several interactions and phenomena, including the spin Hall effect, voltage-controlled magnetic anisotropy effect, skyrmion–skyrmion interaction, and skyrmion–edge interaction. The proposed logic gates can perform the basic Boolean operations of the logic AND, OR, NOT, NAND, and NOR gates. Our results may have a great impact on fundamental physics and be useful for designing future nonvolatile logic computing devices with ultra-low energy consumption and ultra-high storage density.
Time-resolved cathodoluminescence in an ultrafast transmission electron microscope
Authors: Meuret S. , Tizei L. H. G. , Houdellier F. , Weber S. , Auad Y. , Tencé M. , Chang H.-C. , Kociak M. , Arbouet A.
Published: August 2021

Ultrafast transmission electron microscopy (UTEM) combines sub-picosecond time-resolution with the versatility of TEM spectroscopies. It allows us to study the ultrafast materials' response using complementary techniques. However, until now, time-resolved cathodoluminescence was unavailable in UTEM. In this paper, we report time-resolved cathodoluminescence measurements in an ultrafast transmission electron microscope. We mapped the spatial variations of the emission dynamics from nano-diamonds with a high density of NV centers with a 12 nm spatial resolution and sub-nanosecond temporal resolution. This development will allow us to study the emission dynamics from quantum emitters with a unique spatiotemporal resolution and benefit from the wealth of complementary signals provided by transmission electron microscopes. It will further expand the possibilities of ultrafast transmission electron microscopes, paving the way to the investigation of the quantum aspects of an electron/sample interaction.
Effect of an upstream cylinder on the wake dynamics of two tandem cylinders with different diameters at low Reynolds numbers
Authors: Shan Xiangjun
Published: August 2021

This paper presents a systematic numerical study on the fluid dynamics and flow structures around a cylinder with diameter D placed in the wake of another cylinder with a smaller diameter d. Reynolds numbers of Re = 100 and 150 (based on D) are considered so the flow is physically two-dimensional. The ratios d/D and L/D vary in the ranges of 0.4–1.0 and 1.0–8.0, respectively, where L is the distance from the center of the upstream cylinder to the forward stagnation point of the downstream cylinder. The analysis focuses on how d/D and L/D influence the Strouhal number St, wake topology, and fluid forces on the downstream cylinder and links them with the flow physics. The flow is classified into the reattachment and co-shedding flow regimes, with the latter being further subdivided into the prime vortex shedding, two-layer vortex shedding, and secondary vortex shedding (SVS) modes, and the detailed aspects of the three modes are discussed based on the time-averaged flow fields. The two vortex frequencies of the downstream cylinder can be detected only in the SVS mode, and in addition to the fundamental vortex frequency f1, the shedding of the secondary vortex further results in the subharmonic frequency f2. Only when the secondary shedding length Ls* is  <10 does f2 affect the downstream cylinder and lead to a pattern of alternating high- and low-amplitude peaks in the time history of the lift coefficient. A novel mechanism of secondary vortex formation is identified, and the critical spacing and the modulation of lift by f2 are also discussed.
Generalized Newtonian fluid constitutive equation for polymer liquids considering chain stretch and monomeric friction reduction for very fast flows modeling
Authors: Zatloukal Martin , Drabek Jiri
Published: August 2021

In this work, the recently proposed frame-invariant Generalized Newtonian Fluid (GNF) constitutive equation [M. Zatloukal, “Frame-invariant formulation of novel generalized Newtonian fluid constitutive equation for polymer melts,” Phys. Fluids 32(9), 091705 (2020)] has been modified to provide uniaxial extensional viscosity at a high strain rate limit corresponding to molecular expression for a fully extended Fraenkel chain reported in Ianniruberto et al. [“Melts of linear polymers in fast flows,” Macromolecules 53(13), 5023–5033 (2020)]. It uses basic rheological and molecular parameters together with the ratio of monomeric friction coefficients for equilibrium and fully aligned chains. The modified GNF model was successfully tested by using steady-state uniaxial extensional viscosity data for well-characterized entangled polymer melts and solutions [namely, linear isotactic polypropylenes, poly(n-butyl acrylate), polyisoprenes, and polystyrenes] covering a wide range of strain rates, including those, at which the chain stretch occurs. Only two fitting parameters were sufficient to describe all uniaxial extensional viscosity data, one related to the Rouse stretch time and the other controlling the extensional thinning and thickening behavior at medium and high strain rates. The model was compared to five different advanced viscoelastic constitutive equations, which are based on Doi–Edwards theory and include chain stretch along with a number of important additions. The ability of the proposed GNF model to represent steady uniaxial extensional viscosities under fast flow conditions for entangled polymer fluids has been shown to be superior to the predictions of selected advanced viscoelastic constitutive equations. It is believed that the modified GNF model can be used in the stable modeling of non-Newtonian polymer liquids, especially in very fast steady-state flows where chain stretch begins to occur.
Optical response of laser-driven charge-transfer complex described by Holstein–Hubbard model coupled to heat baths: Hierarchical equations of motion approach
Authors: Nakamura Kiyoto , Tanimura Yoshitaka
Published: August 2021

We investigate the optical response of a charge-transfer complex in a condensed phase driven by an external laser field. Our model includes an instantaneous short-range Coulomb interaction and a local optical vibrational mode described by the Holstein–Hubbard (HH) model. Although characterization of the HH model for a bulk system has typically been conducted using a complex phase diagram, this approach is not sufficient for investigations of dynamical behavior at finite temperature, in particular for studies of nonlinear optical properties, where the time irreversibility of the dynamics that arises from the environment becomes significant. We therefore include heat baths with infinite heat capacity in the model to introduce thermal effects characterized by fluctuation and dissipation to the system dynamics. By reducing the number of degrees of freedom of the heat baths, we derive numerically “exact” hierarchical equations of motion for the reduced density matrix of the HH system. As demonstrations, we calculate the optical response of the system in two- and four-site cases under external electric fields. The results indicate that the effective strength of the system–bath coupling becomes large as the number of sites increases. Excitation of electrons promotes the conductivity when the Coulomb repulsion is equivalent to or dominates the electron–phonon coupling, whereas excitation of optical vibrations always suppresses the conductivity.
Novel allosteric ligands of the angiotensin receptor AT1R as autoantibody blockers
Authors: Singh Khuraijam Dhanachandra , Jara Zaira P. , Harford Terri , Saha Prasenjit Prasad , Pardhi Triveni R. , Desnoyer Russell , Karnik Sadashiva S.
Published: August 2021

Significance

High-resolution structural knowledge is a key driver for discovering small molecules to target functional motifs in G protein-coupled receptors (GPCRs). Reports of autoantibodies targeting extracellular motifs of GPCRs are increasing with no therapies in sight. We address this void using the autoantibody epitope of AT1R as target to discover small molecule inhibitors of AT1R antibody. Resulting inhibitors also exerted allosteric effects on AT1R agonist signaling. This knowledge is useful for consideration of small molecule autoantibody inhibitor development for other GPCRs in which cryptic allosteric sites can be harnessed, and pharmacological intervention with allosteric ligands is desirable. In the case of AT1R, developing new generation of neutral, negative, or positive allosteric ligand therapeutics appears feasible through rational drug design approaches.
Comprehensible narratives and connected grammar
Authors: Yang Lei
Published: August 2021

Classical Chinese is an integral component of the Chinese language curriculum at many American universities. However, which texts should be taught and how their grammar should be introduced in a textbook, are questions that have seldom been discussed. This article focuses on the selection of original texts and the mode of grammar explanation in an introductory-level textbook for undergraduate students who study Chinese as a second language. In the United States, more and more students study Classical Chinese for Mandarin-proficiency improvement and Chinese cultural perceptions. Responding to the trend, I argue that narrative texts and comparative grammar explanation would not only render a textbook more comprehensible and engaging, but also advance the learner’s practice of Classical Chinese knowledge in Modern Chinese production. This new design thus effectively connects Classical and Modern Chinese in both “content” and “form,” providing a new perspective to the curriculum development of overseas Chinese programs.
Pathways to split ergativity
Authors: Dahl Eystein
Published: August 2021

This paper reassesses the rise of ergative alignment in Anatolian and Indo-Aryan, two branches of the Indo-European linguistic family. Both of these branches acquire split-ergative morphosyntax in the course of their history but via different grammaticalization paths and with different results. In the Anatolian language Hittite, a denominative derivational suffix develops into an ergative case marker, which is restricted to so-called neuter nouns. In Indo-Aryan, on the other hand, a new ergative category with anterior aspectual semantics emerges in Middle Indo-Aryan originating from a P-oriented resultative construction in Old Indo-Aryan.
Progress in detecting and mapping crop diseases, with particular reference to maize using remote sensing
Authors: Mutanga Onisimo , Dhau Inos , Dube Timothy , Adam Elhadi , Ayisi Kingsley K.
Published: August 2021

Disease infection on crops has been increasing over the years, in line with the changing climate, which has provided a conducive environment for disease proliferation. Timely and up-to-date information on disease spread and its magnitude is a critical component of crop management. This study provides a detailed overview on the role of remote sensing in crop disease detection and mapping with particular reference to the implication on maize, a staple food for many countries in the Global South. Studies have shown the capability of various remote sensing approaches in detecting the severity of disease infection. Most studies undertaken focused on disease classification, with hyperspectral data demonstrating satisfactory performance in detecting the early stages of disease infection. Thermal remote sensing has great potential but remains largely unexplored and very few studies have focused on the application of remote sensing on maize crop diseases in different environments. With new developments on unmanned aerial vehicles (AUVs), there is a great potential to mount sensors with useful information for precise crop disease monitoring and the large size and architecture of maize leaves provide opportunities for early detection with high-resolution remotely sensed data.
Ageing brain and geopolitical leadership: a bio-psycho-sociological approach to the fall of Sharif of Mecca Husayn bin Ali, 1908–1924
Authors: Moñivas Jesús Romero
Published: August 2021

ABSTRACT

In 1908 Husayn ibn Ali was proclaimed Sharif of Mecca, in 1916 King of Hejaz and in 1924 Caliph. However, that same year he had to abdicate and ended his last years in exile. What happened? The case of Husayn aims to show the importance of an interdisciplinary approach for understanding the political behavior. The aim of this article is to show that complex social environments require a single/multi-selves structure and that this structure is more or less balanced or biased between the two poles depending on the person's age and the type of social environment.
Impact of Compliant Wall Properties on Peristaltic Transport of a Compressible Non-Newtonian Maxwellian Fluid Through Axisymmetric Cylindrical Tube
Authors: Eldesoky Islam M , Nayel Mohammed S , Galal Abdallah A , Raslan Hagar M
Published: August 2021

In this article, Maxwell’s viscous fluid movement is studied through a cylindrical symmetric tube (pore) with a complaint wall and this movement is peristaltic. The fluid’s compressibility and slip effect have been taken into consideration. The problem was solved with the perturbation approach in terms of small amount that triggers amplitude ratio. Second-order approximation, the net flux caused by the moving wave is determined for various physical parameters like the wall tension, damping force, wall rigidity, slip parameter, wave number, relaxation time and compressibility parameter. The impacts of interested parameters are discussed numerically and illustrated graphically. In various fields of study, such as biological sciences, There are many applications of this study represented in studying blood flow in living things and in industry as well as simulating fluid flow through flexible tubes.
Fuzzy estimation for the difference between two means using different algorithms
Authors: Nigm Khaled Abu-Bakr , Ismail Ahmed Salah , Elsherif Ahmed K
Published: August 2021

New fuzzy algorithms for estimating the difference between two means of two independent random samples have been presented. Algorithms calculations have been done using different assumptions under condition the fuzziness of data which has been defined as Triangular Fuzzy Number because of its simplicity in calculations and its wide use in various applications. First, providing the estimation of the difference between two means by considering the two variances of each sample are known. Second, considering the two variances of the two samples are unknown but equal. Third, estimating the difference between two means by considering the two variances are unknown and unequal. Then, under the same assumptions of variances in the preceding three assumptions the difference between two means under condition crisp data based on different significance levels has been calculated. Finally, the advantages of using fuzzy algorithms have been presented.
Mobile Robot Position Estimation using Milstein Algorithm
Authors: Abd Elfatah Mohamed G , Zaky Hany Nasry , Shams Ahmed
Published: August 2021

Stochastic differential equation (SDE) became a very important mathematical tool in modeling and performance analysis of many systems due to the white noise appeared in them. one of the significant problems is the time delay problem which appeared in many teleoperated systems which has a significant effect in the system performance. The target in this paper is to approximate the mobile robot future position to decrease the time delay in teleoperation. As a result of white noise, heading angle equation of the mobile robot will be converted into a SDE. The approximated solution has been improved by using a higher order of convergence numerical algorithm (Milstein algorithm) with order of convergence equal one for better estimation of future position of mobile robot. The error has been decreased in many parts of the robot path. A simulated results and a comparison between the two numerical algorithms are explained.
Studying of DC Electrical Properties for Gold Sputtered PM-355 Thin Films after Annealing and Ion Beam Irradiation
Authors: Radwan S I , Rashad A M , Tantawy H R
Published: August 2021

This article investigated the dc electrical properties of Au / PM-355 thin films synthesized using magnetron sputtering. PM-355 specimens were cleaned by ethanol and then were deposited by gold of different thicknesses equal to 300, 400, 500, 700, 1000, 1300, and 1500 nm. From dc electrical measurements as resistance, resistivity and conductivity were investigated for these thin films due to determine the optimum Au thickness with good characteristic. Then, this optimum thickness was treated by annealing in air up to 140 °C for 30 minutes. Hence, another organic cleaner, chloroform, was used before the deposition of optimum thickness forming thin film. Also, study the effect of nitrogen ion beam extracted from conical anode-disc cathode ion source carried out for 30 minutes with operating conditions on the organic cleaners and annealing Au / PM-355 thin films. Moreover, Shore D hardness tester was used to measure micro-hardness for all thin films compared by blank PM-355. Then, the comparison was done between the thin films through dc electrical conductivity and micro-hardness data at the absence and presence of ion beam irradiation. Finally, the change in surface morphology of thin films due to different treatments can be observed by scanning electron microscope.
Preparation and Properties of Epoxy Resin Based Conductive Composites
Authors: Yao Shan-Shan , Li Min-Yi , Jin Fan-Long
Published: August 2021

The epoxy resin-based conductive composite was prepared by filling the epoxy resin with carbon fiber powder and graphene. The influence of the additive quantity on the conductive properties and mechanical properties were investigated, and the influence of carbon fiber powder surface treatment on the conductive properties and mechanical properties were investigated. The results show that the addition of carbon fiber powder and graphene can improve the conductivity and mechanical properties of epoxy composites.
Progress in Research of Dragon Rolled Plates
Authors: Lei Wu , Ming Qin , Bing He , Bin Gu
Published: August 2021

Progress in research of dragon rolled thick plates are summarized in this paper. Basic characteristics, reduction and gap supplement, plate bending, rolling force and energy parameters, shear deformation at the center of the thick plates and the materials and methods in current research were introduced. Although the potential of the application of dragon rolling in thick plate production is obvious, there are still many unsolved problems, especially that the experimental data is still less, therefore there is still a lot of work to do from the practical application.
Study on the electrical properties of itaconic acid-based epoxy resin
Authors: Guo Yuntian
Published: August 2021

Plastic limit orders have been upgraded successively, and the pressure on environmental protection has continued to increase. In the field of electrical insulation, the use of bio-based epoxy resin as a substitute for petroleum-based resin reduces the consumption of petroleum resources while also reducing environmental pollution, which is an effective way to realize environmental pollution of electrical materials. In this paper, bisphenol A epoxy resin (DGEBA) and an important bio-based epoxy resin-itaconic acid-based epoxy resin (EIA) were cured under the same conditions to obtain their epoxy network. And its electrical performance has been tested in terms of breakdown field strength, leakage current and dielectric loss factor. It is concluded that EIA has the potential to replace DGEBA in a certain field of power system.
Mechanical properties analysis and experiment on Multi-order excavation shovel of Ophiopogon japonicas harvester
Authors: Zhao Bangtai , Men Linsen , Song Lejian , Wang Yipeng , Ye Jianghong , Jiang Huixia , Liu Yu , Luo Jun , Guo Jia , Guo Xi
Published: August 2021

Aiming at the poor soil crushing capacity and low operating efficiency of the Ophiopogon harvester, reference to potato, panax notoginseng and other block root excavation device. Based on the soil crushing theory, mechanical analysis of the excavation shovel was performed, and the multi-order excavation shovel of Ophiopogon japonicas harvester was designed. Through ANSYS Workbench Mechanical properties analysis of the excavation shovel, obtained the inclination stress-strain cloud map of soil inlet angle and shovel surface. Combined with the stress-strain results, production suggestions were proposed. Binary regression analysis, response surface analysis and reoptimization design of mining parameters were conducted through field test and Design-Expert 12 software. Test results show that when the inlet angle was 25 °, inclination angle was 170 °, tool forward speed was 0.35m/s, Harvest rate was 98.37% and damage rate was 1.35%, ophiopogon japonicas Harvest worked efficiency. Meet the relevant operating requirements of Ophiopogon japonicus harvester.
Microstructure and Properties of Two Cr8 Cold Working Die Steel
Authors: Sha Yuan , Leyu Zhou , Zhengyu Wang , Peng Jiang
Published: August 2021

In this paper, we studied the effect on microstructure and properties during low tempering and high tempering temperature of HNC53 and KD11max Cr8 cold working die steel by means of hardness tester, universal tensile testing machine, pendulum impact tester, metallographic microscope, SEM and EDS. The results showed that the microstructure of the two materials were spheroidized pearlite and large eutectic carbide. After quenching then tempering at high temperature 520°C and low temperature 200°C, the microstructure was martensite, eutectic carbide with large particles and small secondary precipitated carbide which was M7C3 type carbide. When KD11max was tempered at high temperature of 520°C, more nano-level secondary carbonization precipitated, and secondary hardening phenomenon was more obvious. The increase of Si and decrease of C could promote secondary hardening and improve the impact toughness of materials. KD11max impact toughness was better than HNC53.
Simulation and optimization of casting process for aluminum alloy special-shaped parts
Authors: Min CHEN , Yi WANG , Jigui ZHANG , Jiang FU , Jianjun MA
Published: August 2021

This article is aimed at an aluminum alloy special-shaped part, which has a hollow connection inside, and there are multiple cross-sections that are constantly changing, and it is difficult to design the casting process. In response to this difficulty, combined with the existing sand casting, metal casting and investment casting production lines of the factory, the casting process plan is designed and optimized now. With the help of the numerical simulation software Anycasting, through the simulation analysis of the casting process, the problem that the castings are prone to defects in the thin wall and the bottom plate is solved. The conclusions obtained from the simulation analysis were applied to the actual production process, and qualified castings were produced.
Research on temperature-magnetic properties based on metal magnetic memory testing technology
Authors: Bi Zhenfa , Wu Tao , Fang Pengli , Wang Zongkai
Published: August 2021

during the running of high-speed railway, the vibration and friction between wheel set and track will cause the temperature rise between wheel set and track. The metal magnetic memory detection technology is used to detect the small fault of wheel set, and the temperature will have a certain impact on the magnetic memory signal. In order to study the quantitative relationship between temperature and magnetic memory signal, the temperature magnetic property of 25CrMo4 material is proposed in this paper. Through the temperature magnetic experiment and simulation analysis of the material specimen, it is concluded that when the temperature is lower than Curie point, the magnetic flux leakage of the sheet is basically stable. The value in tangential direction is 130A/m, and the value in normal direction is 0A/m. When the temperature reaches Curie point, the value of the tangential direction changes to 169.9 A/m, and the normal direction is still 0A/m; And the temperature magnetic numerical simulation curve is constructed, which provides the basis for carrying out magnetic signal to material small fault under coupling load, and provides the basis for non-destructive testing.
Study on properties of permeable brick
Authors: Zhixuan Zhang , Bin Yang , Na Zhu , Ying Lin , Bo Ma , Meijie Wang , Yujuan Liu
Published: August 2021

The performance research and preparation methods of different kinds of permeable brick are analyzed and summarized, which shows the wide application prospect of permeable brick.
Structure of Ag-Cu clusters resolved by absorption, Raman and vibrational spectroscopy
Authors: Li Weiyin , Zhao Tongtong , Ding Lingling , Zhang Sha
Published: August 2021

The structures of Ag9, Ag10, Ag8Cu1, and Ag6Cu3 clusters and their optical, Raman and vibrational spectra are calculated by GGA/PBE. The results display that the structures of the Ag9, Ag10 and Ag8Cu1 (three isomers) clusters can be distinguished by comparing their energies and optical, Raman and vibrational spectra. The difference between the two isomers of the Ag6Cu3 clusters cannot be distinguished by comparing their energies and cannot be directly observed, with their uniform shapes proved by their optical, Raman and vibrational spectra.
Analysis of droplet transition features and weld formation in laser-MIG hybrid welding
Authors: Ye Guangwen , Zhang Nanfeng , Liu Qianwen , Gao Xiangdong
Published: August 2021

The image of laser-MIG hybrid welding process was collected by high-speed camera, the arc area and the barycenter of droplet were extracted by image processing method, the weld width and weld height were extracted from the 3D point cloud of weldment surface, and the relationship between droplet transition features, droplet velocity and weld formation were analyzed. Results show that the extremum of arc area and droplet transition period have the same change trend. The change of droplet velocity can effectively reflect the change of weld width. The decrease of arc length can increase the droplet transition frequency, speed up the droplet velocity and increase the weld width. The abrupt increase of arc length will increase the ratio of height to width, which reduce the welding quality.
Welding parameters effect and optimization on bead geometry during arc additive manufacturing
Authors: Ma Bo , Zhang Nanfeng , Zhang Yanxi , Gao Xiangdong
Published: August 2021

This paper discusses the effect of parameters in MIG based wire and arc additive manufacturing (WAAM) using stainless-steel wire and Q235 as substrate. The response surface methodology (RSM) and ANOVA were used to determine the effects of current, voltage, and welding velocity on the responses of bead height and width. It was found that voltage had the largest effect on the bead width, followed by welding velocity and current. But on the bead height, welding velocity is the most significant parameter, followed by current and voltage. The genetic algorithm (GA) was utilized to optimize the parameters to obtain the maximum ratio of weld bead width to height for multi-layer single-pass arc additive deposition.
Evaluation of welding process stability and weld formation during laser-MIG hybrid welding
Authors: Fan Xi’an , Wang Congyi , Zhang Nanfeng , Zhang Yanxi , Song Yaowu , Gao Xiangdong
Published: August 2021

In laser-MIG hybrid welding, the visual information can be used to monitor the stability of the process and estimate the weld formation. Taking the hybrid welding of ER308 stainless steel as an example, a high-speed camera is used to simultaneously obtain visual information of top and bottom of the weldment during the welding process. Combined with the visual characteristics of arc light, molten hump and spatter at the bottom, the influence of various welding state characteristics on weld formation was analyzed. The comparison between the welding process of good weld and root humps illustrated that the time series curves of the area and centroid coordinates of the molten hump at the bottom can reflect the formation process of the root humps. The main cause of root humps is the lack of heat input. The results support a basis for monitoring and controlling the laser–MIG hybrid welding process status.
A method for optimizing electromagnetic ultrasonic probe based on the spatial distribution of permanent magnets
Authors: Li Shaoli , Huang Jing , Luo Ningzhao
Published: August 2021

The external magnetic field of a single permanent magnet is modeled by the vector magnetic potential method based on the Ampere hypothesis, which is compared with the finite element method to analyze the external magnetic field of the permanent magnet. Based on this, the mathematical models of the external magnetic field of multiple permanent magnets are obtained. By analyzing the external magnetic field of the permanent magnet of an electromagnetic ultrasonic probe proposed in this paper, the influence of the parameters of the permanent magnet on the external magnetic field is studied. The optimized structure containing multiple permanent magnets can increase the vertical component of magnetic field strength by about 32.3% compared with that of a single permanent magnet.
Optimization of Assembly Process Design about Cable based on MBD in Spacecraft Field
Authors: Song Xiaohui , Wang Wei , Zhang Qian , Liu Zhe , Wang Pei , Xue Feng
Published: August 2021

An important part of the low-frequency cable network spacecraft, in order to improve the efficiency of the spacecraft’s low-frequency cable network assembly process, according to the characteristics of the spacecraft cable network, based on the three-dimensional digital design of the spacecraft cable network, the spacecraft based on the three-dimensional model. The design and optimization of the cable network final assembly, a digital cable network final assembly was proposed to achieve the purpose of improving the efficiency and reliability of the cable network final assembly.
Detection of Prohibited Articles based on Lightweight Convolution Neural Network
Authors: Lin Xintao , Zhang Yanxi , Zhang Nanfeng , Gao Xiangdong , Ruan Jieshan
Published: August 2021

Prohibited articles detection is an important way to ensure public safety. In order to improve the flexibility of security inspections in complex public places, this paper uses three different convolutional neural networks, YOLOv3, MobileNet-SSD, and YOLOv3-Tiny, to detect the prohibited articles on the security inspection image data. Two performance indicators, mean Average Precision and Frames Per Second, were used to test the effect of the propose model. Finally, this trained model was deployed to the Raspberry Pi mobile device. Experimental results show that using YOLOv3-Tiny model for prohibited articles detection can improve the detection speed by about 10 times and the high detection precision is also maintained. This experiment provides a research idea for the fast detection of prohibited articles on mobile devices.
Design of Smart Bearing with Wireless Monitoring System
Authors: Xinhao Lv , Wen Wang
Published: August 2021

The paper takes the STM32F103VET6 as the core of the embedded system for wireless monitoring. This paper mainly introduces the design process of system hardware and software. The system can monitor the real-time inclination angle and temperature signals in the process of bearing operation. The monitored signals are transmitted to the host computer through the serial port. Meanwhile, they are also transmitted to the remote mobile phone through the Internet of Things.
Study on the Ice-Coated Brake Disc for EMUs Based on Force Coupling
Authors: Zuo Jianyong , Wang Xueping , Liu Jialiang
Published: August 2021

Based on the abnormal wear of the brake disc of Electrical Multiple Units (EMUs), considering the ice-coated friction pair, the finite element (FE) models of the brake disc, the friction blocks and ice impurity were established in ANSYS to explore the stress characteristics of the brake disc. For the ice-coated model, it is found that the maximum equivalent stress is 956.75MPa under the condition of pad stress of 25kN and initial braking speed of 250 km/h. The value of the maximum stress on brake disc surface decreased by 400MPa while removing the ice impurity. The maximum Z-displacement on the ice-coated disc is nearly 4.7mm, and with the contact point farther away, the smaller the deformation will be. The overall trend of the equivalent stress and Z-displacement of the brake disc increases with the braking pressure increasing. Droplet-like frictional blocks can improve the maximum stress and Z-displacement of the disc. Therefore, it is suggested that droplet -like frictional blocks are used for the braking equipment. For improving abnormal wear of the brake disc in extremely cold and snow environment, the analysis provides important reference and theoretical basis for engineering.
A Novel Parametric Design Method of Three-section Bioabsorbable Interface Screw
Authors: Chen Lihua , Meng Xianyuan , Dong Wenxing , Shan Lutong
Published: August 2021

Bioabsorbable interface screw is a kind of fixation instrument which uses interference fit to produce tightening force. The mechanical properties of interface screws, which are mainly used for cruciate ligament reconstruction surgery, have a strong correlation with thread parameters. Due to the different contact stresses caused by the different contact environments of each section of the interface screw after knee ligament reconstruction, this paper proposed a parametric design method for the three-section interface screw. In this study, the cross-section perpendicular to the axis was used as the reference plane for modeling, and a mathematical model of the structural parameters of each cross-section was established. Finally, through the python module of the open design platform GRASSHOPPER, the mathematical model established was applied to the parametric design of the interface screw.
Research on Remote Monitoring Based on Cloud for Electric Air Compressor of Rail Vehicle
Authors: Li Qingxuan , Zhang Xuan , Xie Shangyi , Zhang Shixi , Zhang Lihao
Published: August 2021

At present, there is no remote monitoring system for air compressors used in rail vehicles, Every time the vehicle is put into the warehouse, the inspector needs to check the appearance of the vchicle, So this kind of inspection method can only find out whether the surface is abnormal, Can not find out whether there is a problem inside the air compressor. In view of the above situation, the remote monitoring device is specially designed for air compressors used in rail transit industry to collect the dew point, temperature and air pressure of the output port of air compressors in real time, and send them to mobile phones and computers through cloud remote transmission, so as to detect whether there are abnormalities in air compressors in advance through data analysis, which is convenient for timely maintenance, reduce the risk of vehicle operation, and no personnel inspection when warehousing.
Simulation and selection of fin stabilizers for polar cruise ships based on Computational Fluid Dynamics
Authors: Zhao Yunrui , Gao Haibo , Zhang Shaoshu , Lin Zhiguo , Guo Yunhua , Hu Yi
Published: August 2021

Polar cruise ships have high requirements for comfort, so it is an important problem to select fin stabilizers matching with the target ship. The underwater movement under the maximum sailing speed and the active anti-rolling of the fin stabilizers under the low sailing speed of an 8035 gross tonnage polar cruise ship are simulated by means of Computational Fluid Dynamics (CFD) simulation, and the hydrodynamic characteristics of the fin stabilizers are explored. The fin type of NACA0012 is selected for the target ship by analyzing the lift and drag characteristics of two common fin types of NACA0012 and NACA0015. The limiting fin angle of fin stabilizers is found to be about 15~20° at the maximum speed and about 30-35° at the low speed. The research results can provide a reference for the design and selection of fin stabilize.
Analyzation and solution of disconnecting fault of high-speed and heavy-duty shift gearbox
Authors: Peng Xiao , Haoliang Lv , Cheng Wang , Zeming Lin
Published: August 2021

In order to solve the disconnecting fault of high-speed shift gear box, this paper uses finite element analysis to study the wear of transmission fork, the transmission of axial force by gear and the cause analysis of gear synchronizer disconnecting fault. A kind of oil film technology is put forward to form oil film between the contact working face of gear sleeve and shifting fork slider, so as to achieve the friction effect of separating the two friction surfaces by liquid. At the same time, the improvement scheme of shift fork material is changed to solve the problem of gearbox fork wear and disconnection. The reliability and stability of the transmission shift mechanism are improved.
Design of Bolts Structure of Overhead Contract Line Based on Finite Element Method
Authors: Yong Xu , xiaojuan Lu
Published: August 2021

The existing factory-type bolts of Overhead Contract Line are easy to fall off after installation. In order to solve this problem. Firstly, a new type of factory-type bolts that can fasten concrete pillars is proposed for the purpose of clamping and fastening reliability and safety. This new type of factory-type bolts adds a T-type bolts and locknut on the basis of the original factory-type bolts.Secondly, the theoretical calculation formula of the maximum stress when the stress is concentrated in the circular hole on the bolt rod is deduced by using the theory of elasticity.Finally, the finite element method is used to analyze the stress of the new type of factory-type bolts. Research indicates: The simulation verifies the correctness of the theoretical calculation formula, The new factory-type bolts have great practical application value.
Experimental Research on Noise Load Characteristics of Supersonic Jets in Rectangular Nozzles with Different Mach Numbers
Authors: Liu Jiacheng , Yang DangGuo , Li Hu , Tian BaoWei , Zhang ShuHai , Zhao JiaYi , Gao RongZhao
Published: August 2021

Aiming at the jet noise problem of the rectangular supersonic nozzle, rectangular nozzle test models with Mach numbers of 1.35 and 1.65 were designed and processed. Using the jet noise test platform in a full anechoic chamber, the nozzle supersonic jet noise characteristic test was carried out. The test results show that the surface noise load of the model gradually increases along the nozzle axis; the unsteady flow field structure at the nozzle exit position has complex evolution, with strong turbulent pulsation and high noise load; the directivity trend of the far-field noise total pressure level of the two nozzles is basically the same, and the directivity is obvious in the upstream and 90° direction of the nozzles; from the far-field sound pressure spectrum, it can be seen that the far-field noise is composed of broadband noise and discrete frequency noise. The amplitude of the second order frequency varies significantly from 70° to 90° of upstream, and the fourth harmonic frequency of the whistling mode is captured in the direction of 90°.
Optimization of injection molding of display panel based on PSO-BP neural network
Authors: Qiuli Li , LePing Bu , Hui Luo , Hailin Li , Yonghao Zhao
Published: August 2021

aiming at the practical production problem of large thin-wall plastic parts with large warping deformation and shrinkage during injection molding, the injection process parameters were optimized by CAE technology and neural network prediction method, to obtain high quality plastic finished products. Particle swarm optimization (PSO) algorithm was used to improve the BP neural network, and based on the neural network, the prediction model between injection process parameters and warpage deformation, volume shrinkage was constructed. The min-variables of the two parameters are accurately predicted by the model, and the best injection molding parameters are obtained. Through the verification of the mold test, the molding quality of the plastic parts is improved, the production cycle of the mold is shortened, and the economic benefit of the mold production is improved.
Prohibited Items Detection in X-ray Images Based on Attention Mechanism
Authors: Liang Tianfen , Lv Bo , Zhang Nanfeng , Yuan Jinhao , Zhang Yanxi , Gao Xiangdong
Published: August 2021

Security inspection is an important measure to ensure public safety. At present, X-ray security inspection equipment is widely used in security checkpoints. However, it is not efficient to recognize prohibited items in X-ray images manually. Automated security inspection system has become the development trend of security field. In this paper, the Yolov4 detector was used to detect prohibited items in X-ray images. In order to improve the detection performance, we added CBAM attention modules to different parts of Yolov4. A public dataset is used for simulation experiments, which shows that the addition of CBAM can effectively improve the detection performance of the detector.
A fault alarm monitor method for safety-critical software
Authors: Yu Yi , Wang Xiaoyong , Shi Cong , Chu Pengzi , Xu Ye
Published: August 2021

A design by contract (DBC) technology-based software fault alarm monitor method is discussed in this paper. Firstly, this method assigns a static module code to each software module, and assigns a static fault code to each fault alarm message in the software module. When the software is running, the dynamic module code is allocated before the software module is executed. When the software module is executed, the current module code is record, the fault alarm message is checked and collected. When a fault information is detected, all internal states of the system are recorded to the external memory, and the system is oriented to safety. At the end of the normal execution of the software module, the recorded current module code is erased. Finally, the fault analysis diagnostic tool is used to analyse the output fault message. Compared with the previous methods, the method can quickly locate the fault location, analyse the cause of the alarm, and improve the safety and maintainability of the software.
Gearbox fault diagnosis based on transfer learning with RseNet50 model
Authors: He Chen , Jiang Yiqiang , Sun Li , Wu Bin
Published: August 2021

The fault diagnosis method based on ResNet50 convolutional neural network and migration learning is proposed as a way of improving the gearbox fault diagnosis. Firstly, exporting the normal and faulty data of the gearbox. Then converting the exported data into one-dimensional images to and generate the corresponding training and test sets, train in the model to get accuracy of the test set and training set. After fine adjustment, it is used for gearbox fault diagnosis, compared with the VGG16, ResNet101, and GoogleNet model, the accuracy of ResNet50 is above 86.6%. It has a good prospect of application, and its effect is obviously better than that of other models.
Lightweight design of aircraft truss based on topology and size optimization
Authors: Qiu Jiyuan , Fan Yunting , Wei Haolin , Zhang Peng
Published: August 2021

Truss structure is widely used in aircraft design. In this paper, the lightweight design of a certain type of aircraft truss structure is carried out through topology analysis and size optimization to improve the performance of the aircraft. The original truss model is established based on ABAQUS, and its static strength is checked and analyzed. According to the design domain of the original model, a topology optimization method is used to obtain a new material distribution. Then the section size of each truss member is taken as the optimization variable, the maximum deformation of the structure is taken as the constraint, and the overall model volume is the minimum as the optimization goal, the genetic algorithm is used to obtain the new structure size. The results show that the truss members after the second optimization can meet the requirements of use and have a 75.15% reduction in mass compared to the original structure, which verifies that the method is feasible and provides a new idea for the lightweight design of truss structures.
Structural Design of Steel Bar Bending Machine
Authors: Jiang Ying , Cheng Xiaofei , Li Hongji , Ren Xinghua , Li YueYang
Published: August 2021

In order to solve the current situation of the sharp increase of steel consumption in China, a steel bending machine with adjustable support is designed. This design selects a reasonable power source, and designs an efficient deceleration device and executive system. The design of reducer includes belt, gear, shaft and key; The executive system includes rotatable support block, lead screw, lead screw base, bending core, working disc and other parts; and the working performance of the important parts inside the bending machine is analyzed. This design can control the bending speed at 20 meters per minute and the bending diameter at Φ18mm~ Φ28mm.
Research on electrode position fuzzy control system of calcium carbide furnace based on constant power
Authors: Wei-Wu SHANG , De-Dong ZHOU , Fang SU
Published: August 2021

The adjustment methods of calcium carbide furnace conditions include voltage regulator switches, electrode lifts, and changes in charge resistivity. For slight load changes, electrode lifts are commonly used. In order to have a positive effect on the control, furnace conditions and energy loss of the calcium carbide furnace, this paper proposes a fuzzy control method for the electrode lift of calcium carbide furnace based on constant power. By detecting the electrode current and electrode voltage, the electrode position is obtained indirectly, and then the fuzzy control idea is used to determine the control amount of the electrode lifting, and the control volume is converted into a pulse signal to act on the hydraulic solenoid valve to control the electrode lifting, so as to achieve a constant power consumption of the calcium carbide furnace the goal of. Simulation and practical applications show that this method can effectively avoid arc extinguishing and short-circuit phenomena, and has a certain positive effect on the operation of calcium carbide furnace, improvement of furnace conditions, and energy saving and consumption reduction.
Parametric Design of NC Tangency Point in Archimedes spiral Helical surface
Authors: Qiyue Kang , Baizhan Gao
Published: August 2021

This article based on matlab secondary development on the surface of the archimedean spiral cut NC contacts of parametric design. The generation principle of the spiral surface is described, and the processing error that may be caused by the processing method of the spiral surface is analyzed. In the case of meeting the processing requirements, a larger step length and a larger path distance are selected to calculate the tangent contact points of the spiral surface for CNC machining, and the accuracy of the contact points is verified by Matlab. Finally, a parametric design is carried out for the processing of the spiral curved surface tangent contact.