bluuebunny/crossref_metadata_2025 huggingface dataset:
Insights into the evolution of regulated actin dynamics via characterization of primitive gelsolin/cofilin proteins from Asgard archaea
Authors: Akıl Caner , Tran Linh T. , Orhant-Prioux Magali , Baskaran Yohendran , Manser Edward , Blanchoin Laurent , Robinson Robert C.
Published: August 2020

Significance

Eukaryotic gelsolin superfamily proteins generally comprise three or more related domains. Here we characterize single- and double-domain gelsolins from Thorarchaeota (Thor). Similar domain architectures are present in Heimdall-, Loki-, and Odinarchaeota. Thor gelsolins are functional in regulating rabbit actin in in vitro assays, showing a range of activities including actin filament severing and bundling. These gelsolins bind to the eukaryotic gelsolin/cofilin-binding site on actin. Two-domain, but not one-domain, gelsolins are calcium regulated. Thor gelsolins appear to have the characteristics and structure consistent with primitive gelsolins/cofilins, suggesting that these single- and double-domain gelsolins are a record of a nascent preeukaryotic actin-regulation machinery.
Nonreciprocity as a generic route to traveling states
Authors: You Zhihong , Baskaran Aparna , Marchetti M. Cristina
Published: August 2020

Significance

Effective interactions that break action–reaction symmetry are ubiquitous in systems where interactions are mediated by a nonequilibrium environment. They are also the norm in the living world. By examining the dynamics of a diffusing binary mixture, we demonstrate that antagonistic cross-diffusivities can drive the transition from static to traveling spatial patterns. In the context of an analytically tractable model, we elucidate the nature of the transition and demonstrate that the emergence of traveling or oscillating patterns is a generic consequence of nonreciprocity in multispecies systems described by scalar fields. Our work is directly relevant to the understanding and control of nonequilibrium assembly in mixtures of chemically interacting colloids.
Mouse model of SARS-CoV-2 reveals inflammatory role of type I interferon signaling
Authors: Israelow Benjamin , Song Eric , Mao Tianyang , Lu Peiwen , Meir Amit , Liu Feimei , Alfajaro Mia Madel , Wei Jin , Dong Huiping , Homer Robert J. , Ring Aaron , Wilen Craig B. , Iwasaki Akiko
Published: August 2020

Severe acute respiratory syndrome–coronavirus 2 (SARS-Cov-2) has caused over 13,000,000 cases of coronavirus disease (COVID-19) with a significant fatality rate. Laboratory mice have been the stalwart of therapeutic and vaccine development; however, they do not support infection by SARS-CoV-2 due to the virus’s inability to use the mouse orthologue of its human entry receptor angiotensin-converting enzyme 2 (hACE2). While hACE2 transgenic mice support infection and pathogenesis, these mice are currently limited in availability and are restricted to a single genetic background. Here we report the development of a mouse model of SARS-CoV-2 based on adeno-associated virus (AAV)–mediated expression of hACE2. These mice support viral replication and exhibit pathological findings found in COVID-19 patients. Moreover, we show that type I interferons do not control SARS-CoV-2 replication in vivo but are significant drivers of pathological responses. Thus, the AAV-hACE2 mouse model enables rapid deployment for in-depth analysis following robust SARS-CoV-2 infection with authentic patient-derived virus in mice of diverse genetic backgrounds.
Analysis of the strong decays of Pc(4312) as a pentaquark molecular state with QCD sum rules *
Authors: Wang Zhi-Gang , Wang Xu
Published: August 2020

In this article, we tentatively assign Pc
(4312) to be the

pentaquark molecular state with the spin-parity

, and discuss the factorizable and non-factorizable contributions in the two-point QCD sum rules for the

molecular state in detail to prove the reliability of the single pole approximation in the hadronic spectral density. We study its two-body strong decays with the QCD sum rules, and special attention is paid to match the hadron side with the QCD side of the correlation functions to obtain solid duality. We obtain the partial decay widths

and

, which are compatible with the experimental value of the total width, and support assigning

to be the

pentaquark molecular state.
Logarithmic Regge pole
Authors: Campos S. D.
Published: August 2020

This work presents the subtraction procedure and the Regge cut in the logarithmic Regge pole approach. The subtraction mechanism leads to the same asymptotic behavior as previously obtained in the non-subtraction case. The Regge cut, in contrast, introduces a clear role to the non-leading contributions for the asymptotic behavior of the total cross-section. From these results, some simple parameterization is introduced to fit the experimental data for the proton-proton and antiproton-proton total cross-section above some minimum value up to the cosmic-ray. The fit parameters obtained are used to present predictions for the

-parameter as well as to the elastic slope

at high energies.
Studying the localized CP violation and the branching fraction of the

decay *
Authors: Qi Jing-Juan , Wang Zhen-Yang , Xu Jing , Guo Xin-Heng
Published: August 2020

In this work, we study the localized

violation and the branching fraction of the four-body decay

by employing a quasi-two-body QCD factorization approach. Considering the interference of

and

channels, we predict

and

, respectively, which shows that the interference mechanism of these two channels can induce the localized

violation to this four-body decay. Meanwhile, within the two quark model framework for the scalar mesons

and

, we calculate the direct CP violations and branching fractions of the

and

decays, respectively. The corresponding results are

,

,

and

, indicating that the

violations of these two-body decays are both positive and the branching fractions quite different. These studies provide a new way to investigate the aforementioned four-body decay and can be helpful in clarifying the configuration of the structure of the light scalar meson.
Microstructural analysis of rail tracks defects: case study
Authors: Velaphi Msomi , Conrad Charl Peter Basson , Sipokazi Mabuwa
Published: August 2020

This case study reports on the microstructural analysis performed on the railway with defect. The idea behind was to quantify the origin of these defects that are regular in Western Cape railway network. The chemical composition of the defect revealed the reduction in carbon and manganese content on the surface of the defect. The specimens extracted from the beginning and the end of the defect had higher hardness values compared to those extracted in the middle of the defect. This trend is in correlation with the chemical composition variations. The optical microscopy revealed the decarburization layer at the surface of the defect. This kind of the layer results from the surface being exposed to a constant high temperature. It was then concluded that the South African environmental conditions do not form part on the formation of this failure.
Self-assembled NiTe2 nanocrystals as highly efficient and stable electrocatalyst for hydrogen evolution reaction
Authors: Wang Xinqiang , Chen Yuanfu
Published: August 2020

To develop high-efficient electrocatalysts with excellent stability for hydrogen evolution reaction (HER) is a crucial way to alleviate the serious energy crisis. Recently, transition metal tellurides have been reported as promising catalysts for HER. Herein, self-assembled NiTe2 nanostructures including nanocrystals (NCs) and nanoplates (NPs) were synthesized in different solvents by a facile solvothermal method. As novel electrocatalysts, NiTe2 nanostructures show highly efficient HER performance in acidic medium. Particularly, NiTe2 NCs exhibit much faster kinetics for HER. Compared with NiTe2 NPs, NiTe2 NCs demonstrate superior HER performance with a low onset overpotential of 317 mV vs. RHE and a very small Tafel slope of 36 mV dec−1, which is close to that of noble platinum (Pt) catalyst (30 mV dec−1). Moreover, it exhibits excellent stability with more than 95% high current retention after being tested for 1500 voltammetry cycles. The outstanding HER activity of NiTe2 NCs is attributed to its unique interconnection nanostructure and high conductivity. It is promising for NiTe2 NCs as a highly efficient non-noble-metal electrocatalyst to replace Pt-based materials for hydrogen evolution.
Effect of nano titanium dioxide on mechanical properties of regenerated silk
Authors: Liu Yan , Wang Xiaoliang , Xu Chen , Ma Qiang , Ma Lin , Wu Guohua
Published: August 2020

Silk and spider silk have excellent mechanical properties, and their superior physical properties are closely related to their complex structure. Here, we reported the wet spinning behavior of nanomaterials mixed with silk proteins and study the effect of the different sizes of TiO2 nanoparticles (NPs) on the mechanical properties of regenerated silk. Our study retained silk protein nanofibers in CaCl2-FA solution, and optimized the wet spinning process, and produced high-quality regenerated silk fiber (RSF) with excellent mechanical properties by using TiO2 NPs. Among them, when the TiO2 NPs of 5-10 nm was 4 mg/g(TiO2 NPs/Silk Fibroin(SF)), the tensile stress of the RSF reached at 312.44 ± 20.31 MPa, which is 113.11% higher than the control group; the tensile strain reached 46.55 ± 2.76%, which is 152.85% higher than the control group. And the secondary structure conformation of RSF tended to transform from silk I to silk II, and its β-sheet content was 47.27 ± 0.25%. We found that the mechanical properties of RSF decreased with the size of TiO2 NPs increased. This may be due to the smaller the size of TiO2 NPs and the larger the specific surface area, which can provide more binding sites between TiO2 NPs and silk proteins, and also transformed the RSF conformation from silk I to silk II. The characteristics of this spinning method are simple operation, environmentally friendly, low cost, and large-scale industrialization potential. The method of producing RSF has great potential in the production of textiles and multifunctional materials.
Study on the fractal structure of carbon nanomaterials’ smokescreen
Authors: Wang Xusheng , Song Zibiao , Gao Qian , Song Rui
Published: August 2020

In the diffusion of carbon nanomaterials’ smokescreen, the condensates generated by the collision of particles have fractal structures. In order to research this process, this paper is based on DLA condensation model programmed by MATLAB. Using DLA model, the geometrical structure of agglomerate formed by spherical nanoparticles is simulated and the fractal dimensions of agglomerates were computed by using the cyclotron radius method. Large numbers of simulations indicated the fractal dimension of agglomerates on two-dimensional plane distributed between 1.4 and 1.7. And with the increasing number of the particles, the fractal dimension displayed in intensive range. The research in this paper has laid a foundation for the study of the aerodynamic characteristics of condensed particles in the next stage.
Perovskites for printed flexible electronics
Authors: Wang Lei , Wang Yang
Published: August 2020

In recent years, halide perovskites have attracted tremendous attention as active materials in various electronic devices including solar cells, light-emitting diodes, photodetectors, etc. Their excellent optical and electrical properties as well as solution processability make perovskite material an ideal candidate for flexible electronic applications that are manufactured by printing in industrial scale. In this article, the material characteristic and synthetic procedure of perovskite crystals are introduced. Deposition techniques and potential challenges of commercializing perovskite-based flexible electronics are briefly discussed.
Multifunctional coatings formed using organic and inorganic nanomaterials
Authors: Konstantine Nadaraia , Dmitry Mashtalyar , Denis Opra , Igor Imshinetsky , Aleksandr Sokolov , Sergey Sinebryukhov , Sergey Gnedenkov
Published: August 2020

The method of forming composite coatings by the plasma electrolytic oxidation (PEO) using organic and inorganic nanoscale materials is presented. The effect of the incorporated components on the protective properties of the obtained surface layers was studied. It is established that the presence of nanomaterials in the composition of composite coatings makes it possible to reduce the corrosion current density by 4 orders of magnitude in comparison with the base PEO layer. The data of tribological studies confirm a significant increase in the wear resistance of coatings (by 2-4 orders of magnitude). The presence of hydrophobic substances in the composition of composite coatings in combination with the formation technique allows to impart high hydrophobic properties to composite coatings.
Study on the processing map of antibacterial Ti-10Cu sintered alloy
Authors: Shi Liqiu , Yu Feng , Xiang Chun
Published: August 2020

This paper studied the hot deformation behavior of Ti-10Cu sintered alloy in order to optimize the deformation processing. Ti-10Cualloy was prepared by the powder metallurgy method to obtain strong antibacterial property. The deformation temperature range of 800°C to 1000°C and the strain rate range of 0.008 s−1 to 5s−1 were chosen. The constitutive equation in hyperbolic sin functionwas established and thehot processing map was drawn based on the true stress-true strain curves. The microstructure and of the hot deformed alloy were observed in order to reveal the influence of the hot deformation on the microstructure. The results showed that the Ti2Cu phase distributed homogeneously with increasing in the deformation temperature and decreased with the increasing of the strain rate. The final optimized deformation process was:a deformation temperature range of 850°C to 950°C, and a strain rate of 0.1s−1 to 0.5s−1, where a completely homogeneously distributed microstructure would be obtained.
Effects of electromagnetic induction hardening on the microstructure and mechanical properties of B1500HS steel
Authors: Qi Pengyuan , Sun Qi , Zhong Jingyu , Wang Gang , Liu Xianghua , Liu Weijie
Published: August 2020

The effects of electromagnetic induction hardening process on the microstructure, original austenite grain sizes and mechanical properties of B1500HS steel are investigated in this paper. The results indicate that the electromagnetic induction hardening samples can obtain completely martensite with fine lath bundle size, and high tensile strength, which is up to 1626 MPa, and the original austenite grain size is fine and uniform when the heating temperature reaches 900°C. Compares with that of the resistance furnace heating quenching process, the samples treat by rapid heating process can obtain finer lath martensite structure and better mechanical properties after quenching.
Effect of sputtering power on the microstructure of Mg doped ZnO thin films
Authors: Cheng Zhen , Meng Yu , Zhang Bianlian
Published: August 2020

In this paper, Mg doped ZnO thin films were prepared on glass substrates by RF magnetron sputtering. The surface morphology, composition, structure, thickness and refractive index of the films were studied by SEM, XRD and ellipsometer. The results show that the sputtering power has no great influence on the growth direction of the film. When the sputtering power changes from 40 W to 100 W, the crystalline state of the film becomes better, the grain size and the thickness and the refractive index of the film increase with the rising of the sputtering power.
Experimental study on deformation region types and percentages of each region in asymmetrical rolling of strip
Authors: Sun Xiangkun , Liu Xianghua , Qi Junlong , Wang Ji
Published: August 2020

A simple method for dividing the deformation type and a practical model for calculating the percentages of each region in various deformation types are proposed. The percentage of cross-shear zone gradually increases to 100% and the percentages of forward-slip and backward-slip zone gradually decrease to 0 as rolling pass increases with huge roll force and tensions and better lubricating conditions. The method and the model can provide a good reference for better operations during asymmetrical rolling, which is good for rolling industry.
Analysis on corrosion of flat steel used in grounding grid for 220 kV substation
Authors: Chen Hao , Fang Wenxuan , Han Kuo , Qiao Xin
Published: August 2020

Grounding grid plays an important role in protection of main device for power system. With the increase of power capacity and voltage level, the safety of grounding grid is particularly important. In this paper, the seriously corroded flat steel of grounding grid in 220kV substation was investigated by means of different test methods. The result showed that electrode potentials difference existed between different locations on the surface of the buried grounding electrode was the major reason to cause electrochemical corrosion. Meanwhile, higher sulphur and chlorine content of the soil around the substation caused by long-term industrial pollution, led to rapid depletion of zinc coating and acceleration of corrosion process of grounding material. Additionally, effective suggestions were presented in order to reduce the grounding resistance and improve the anti-corrosion performance.
Structural design flow of typical aircraft components based on topology optimization
Authors: Feng Zhijie , Du Jianbin , Zhang Haixi , Wu Kai
Published: August 2020

In the field of structural topology optimization, an important but often neglected problem in previous studies is how to translate the optimal conceptual design obtained by topology optimization to engineering CAD model which can meet requirements of reliability and manufacturability efficiently. This paper carried out exploratory research on full stage design of typical aircraft components. A set of integrated schemes are proposed as a complete design flow from the conceptual design to engineering geometry scheme, including multi-objective dynamic topology optimization, transformation from the optimal topological conceptual design to engineering geometry model, CAE analysis and manufacturing by 3D printing. The method above has strong portability and broad application prospects, which can provide references and technical routes.
A loose self-checking method based on FBG for axle counting sensor
Authors: Zhang Lu , Wang Zhixin , Yan Qiuji , Lin Jinfeng , Wu Chunxiao
Published: August 2020

In order to improve the reliability and safety of the axle counting sensor, a loose self-checking method based on fiber Bragg grating (FBG) is proposed. FBG is used to detect the axial strain of the bolt which is a part of the axle counting sensor. It can effectively detect the installation condition of axle counting sensor. When the axle counting sensor is loose or fall off, the FBG wavelength will be lower than the set threshold value and an alarm signal will be sent. The experimental results show that the measured data of the loose self-checking device under different tightening torques are consistent with the simulation results. The artificial loosening test of the bolt is carried out, which proves that the method can be used to check the loose condition.
MPC-based path tracking with PID speed control for autonomous vehicles
Authors: Chen Shuping , Chen Huiyan
Published: August 2020

In this paper, a new coupled lateral and longitudinal controller based on model predictive control (MPC) framework was proposed for an autonomous vehicle to track the desired trajectory and speed. Considering the constraints of control input limit and state output admissible, we used a spatial-based 8 degrees of freedom (DOF) vehicle model as the prediction model and used a high-fidelity model, i.e., a 14-DOF vehicle model as the plant model in the formulation of MPC algorithm. For the lateral control, the MPC controller generates the optimal road-wheel steering angle; for the longitudinal control, the PID controller embedded in the optimization solution generates the total driving or braking wheel torque. All these control inputs were passed to the plant simultaneously. The developed vehicle models were simulated with step steering input and compared with the simulation result of CarSim vehicle model for validation. We implemented the proposed controller for path tracking and speed control with MATLAB considering an 8-shaped curved trajectory as the reference. The simulation results showed that the path tracking and speed tracking performance were good using the combined lateral and longitudinal control strategy.
Research on multi-task command allocation method for flying wing aircraft
Authors: Zhang Ning , Wang Lixin , Li Feng
Published: August 2020

Flying wing aircraft adopts redundant multiple control surfaces configuration, especially the new type of drag based yaw control device is used in directional axis. Therefore, its command allocation problem has strong nonlinear and multi-axis coupling characteristics. According to the command allocation characteristics of flying wing aircraft, a multi-objective optimization based nonlinear programming method is used for command allocation, and the differences of the control surface command allocation results under different optimization targets is analyzed. The results are also carried out in the attitude tracking simulation based on flight control system designed with nonlinear dynamic inversion. It demonstrates that the different optimization targets have great and quite different impacts on flight states. It proves that the multi-objective optimization based control allocation method is a highly adaptable and flexible command allocation method for flying wing aircraft.
Development of the flatness detection system for cement concrete pavement construction phase
Authors: Liu Ying , Du Tianling , Xie Jinde
Published: August 2020

This article describes a pavement roughness detection system that can be used to test the flatness of the construction phase (before the concrete to harden) cement concrete pavement. The test system is based on optical triangulation principle, by the laser projector and a CCD image sensor camera composition, using a structured light technique for three-dimensional visual measurements. The system can plastic cement concrete pavement flatness detection directly help improve the flatness of the cement concrete pavement.
Structural parameters of new rail transit system optimization theory research
Authors: Wang Zhifei , Li Fan
Published: August 2020

In response to the defects of maglev system structural parameter design method, the paper put forward an optimization design based on orthogonal test and computational fluid dynamics, by combining orthogonal theory with fluid mechanics and adopting multi-factor orthogonal test method, the influence trend of tunnel cross section, running speed, pipeline pressure, and on train aerodynamic resistance is studied by taking train aerodynamic resistance as evaluation index, and the sequence of various factors and the influence of different factors on air drag are determined by range and variance analysis, and the optimal parameters are confirmed. The results show that the blocking ratio has the greatest influence on the aerodynamic drag, while the pipeline pressure has the least influence, and the blocking ratio and running speed have the most significant influence on the aerodynamic drag of the train, while the pipeline pressure is not significant. The optimal solutions are 2 for Tunnel cross section, 600km/h for the running speed and 700Pa for the pipeline pressure. The results of this paper can provide technological interest for the future transportation of the maglev system.
Design of remote wireless cylinder pressure control system
Authors: Wu Ruihan
Published: August 2020

Pressure is an important object monitored in the modern industrial production safety. Aiming at the present situation of pressure monitored, combined with wireless communication technology, this paper puts forward a scheme which monitored the pressure by wireless technology based on Zigbee protocol. The scheme puts the cylinder pressure as a controlled object, selects Zigbee protocol chip CC2530 as the main control device, to achieve control of the pressure regulating valve based on PID algorithm, and realized the pressure control. Through the simulation and experiment it shows that the scheme can realize the wireless remote control of cylinder pressure, and meet the intelligent demand of control system.
Research on pavement garbage detection based on machine vision
Authors: Liu Jiawei , Guan Tian , Zhen Yajing , Zhang Yaoming , Song Xiaoli , Wang Zhaojian , Zhang Dongsheng
Published: August 2020

With the continuous advancement of China’s urbanization process and the continuous development of autonomous driving technology in recent years, it has become a trend to use unmanned garbage sweepers to clean up and maintain the road surface. Garbage detection is an important part of the operation process of unmanned garbage sweeping trucks. It replaces human brains in the process of observing, judging, and locating garbage on the road, which directly affects the efficiency of sweeping trucks. This paper takes Halcon software as the main platform to introduce the research of road garbage detection based on machine vision.
Research on visual vehicle detection and tracking based on deep learning
Authors: Zhang Yaoming , Song Xiaoli , Wang Mengen , Guan Tian , Liu Jiawei , Wang Zhaojian , Zhen Yajing , Zhang Dongsheng , Gu Xiaoyi
Published: August 2020

At present, vehicle tracking technology is still a hot research direction all over the world. The main work of this paper is divided into two parts: we should complete visual vehicle detection based on deep learning and vehicle tracking based on similarity measurement and association algorithm. The main work of this paper is as follows: Based on the YOLOV3 detection algorithm, this paper puts forward some new ideas and ideas, which are applied to the video detection and experimental results. Based on the structure of YOLOV3 convolutional neural network, the vehicle video detection experiment is carried out under the framework of TensorFlow, and the detection results are evaluated by the detection accuracy and error detection rate. Firstly, the augmented data set of video detection is made, and a section of driving record video is recorded under the surrounding road conditions of the school. After that, the data set is used to train the weightless network of YOLOV3. Finally, the test results between KITTI data set and augmented data set are compared. Then the network is used to compare the detection results of different detection algorithms. The second work is to build the vehicle tracking model after getting the object selection frame after video detection. In this model, the classic hog feature extraction method is used to extract the vehicle appearance features, and then the motion similarity is calculated. After getting the total similarity between the targets in the front and back images, the target trajectory is recovered or released by the target trajectory management algorithm to achieve the tracking effect. The above vehicle tracking model is optimized by three evaluation parameters: MOTA, MOTP and IDS. In the end of this paper, the tracking effect experiments under different detection algorithms, different detection thresholds and the peeling analysis of tracking features are carried out for the vehicle tracking part, and some conclusions are obtained.
Research on optimal meshing speed difference based on shift success probability for dog Clutch in automated manual transmission
Authors: Sun Shaohua , Gong Maosen , Wu Baogui , Zou Yupeng
Published: August 2020

The engagement theory for dog Clutch was analyzed and the dynamic model of its engagement process was established. The uncertain result of shift success or failure was described from meshing probability and the shift probability model of dog clutch used in AMT for electric vehicle was established. Afterwards, the factors affecting shift success probability were analyzed by Matlab/Simulink simulation and the optimal meshing speed differences of different gears are defined. Finally, the validity and accuracy of theoretical and simulation analysis ware verified by experiments. The results can be used for designing shift strategy as well as improving shift quality for dog clutch meshing mechanism which used in AMT.
The research on train resistance prediction of low vacuum pipeline based on different neural network algorithms
Authors: Du Chengxin , Wang Zhifei , Li Fan , Feng Ruilong
Published: August 2020

In order to obtain the maximum aerodynamic resistance of low-vacuum pipeline train under different working conditions, this paper uses different neural network algorithms to predict the maximum aerodynamic resistance. First, it calculates 85 groups of maximum resistance values of trains under different operation speeds, pipeline pressure and blocking ratios. Then, it takes 81 groups of data as training samples, establishing and training RBF neural network models, which are based on three different functions, and a linear neural network model as a comparison. Finally, it verifies those models with four groups of randomly selected verification data. The results show that the RBF network prediction model based on Newrbe function has the best prediction effect. It is superior to the other two RBF models in prediction accuracy. The prediction error of the linear neural network model for the maximum resistance of the train is large, and the prediction accuracy is far lower than that of the radial basis function neural network model.
Exploration and practice of intelligent manufacturing of electronic information equipment
Authors: Ben Kecun , Feng Zhanying , Cao Yaqi
Published: August 2020

At present, the global manufacturing industry is accelerating towards the era of digitalization, networking and intelligence. Aiming at the manufacturing characteristics of electronic information equipment, such as the integration of scientific research and production, multi variety and small batch, fast renewal, high coupling of multi disciplines, and huge supply chain, this paper studies and analyzes the technical hotspots of intelligent manufacturing of electronic information equipment, such as 3D printing of mechatronic system structures, design and manufacturing of microsystem, immersive virtual assembly and digital twin. At the same time, based on the guiding ideology of Model-Based Systems Engineering (MBSE), the exploration and practice of electronic information equipment design mode, production mode, support mode and management mode are carried out. The research shows that the application of new technology and mode of intelligent manufacturing effectively shortens the development cycle of electronic information equipment, greatly improves the production efficiency and comprehensive utilization of resources, and significantly reduces the operating cost and the rate of defective products.
Low-loss tunable dielectrics for millimeter-wave phase shifter: from material modelling to device prototyping
Authors: Li Jinfeng
Published: August 2020

Passively controllable millimeter-wave phase shifters based on continuously tunable dielectrics offer promising alternatives to conventional switch-based topologies (e.g. active semiconductor devices and MEMS) with digital resolution. However, only a handful of tunable dielectrics have thus far been identified with high tunability and low loss, among them, liquid crystal (LC) in the nematic phase is of research and development interest. This work presents the modelling of LC materials at 66 GHz based on a novel shielded coplanar device structure in place of traditional waveguides. Phase shifters of 0-π tunability are fabricated and measured, with an insertion loss of -4 dB and return loss lower than -15 dB demonstrated.
Simultaneously static and dynamic layout designs of stiffening structures
Authors: Feng Zhijie , Wu Kai , Liang Xuan , Du Jianbin
Published: August 2020

In the present paper, the topological design problem of lightweight stiffening structures are studied. Multiple design criteria like static compliance, dynamic compliance, eigenfrequency/eigenfrequency gaps and weight are considered simultaneously as sub-objectives in the optimization model. A bound formulation is developed and implemented to deal with the problem concerned, by which the difficulties of non-continuity of the multiple objective functions can be got over. Comparing with the empirical adjustment design or more elaborated parametric design, the topological design may introduce more degrees of design freedom, and thus is possible to produce more innovative conceptual design. The method of sequential convex programming is employed to find the solution of the optimization problem. Numerical examples show that, using the presented approach, the optimized layout of the stiffening structures with enhanced static and dynamic mechanical properties can be obtained.
Stress analysis and design of the waveguide bellows for EAST ECRH system
Authors: Zhang Liyuan , Wang Xiaojie , Liu Fukun , Xu Handong , Wu Dajun , Tang Yunying
Published: August 2020

A 140GHz 4MW long pulse ECRH system for the experimental advanced superconducting tokamak (EAST) has launched in 2011. The waveguide (WG) bellows is an important component in transmission lines, which can absorbs the axial deformation caused by thermal expansion. The flexible WG inside WG bellows dominates bellows performance. In this paper the mechanical analysis including stress analysis and error analysis for flexible WG is presented in detail. A prototype of the WG bellows has been designed and fabricated.
Shafting stiffness calculation of satellite antenna scanning mechanism
Authors: Zhu Jialong , Ma Xiaofei , Wang Hui , Zhao Jiang , Song Tingting
Published: August 2020

As a critical rotating joint component of space mechanism, the shafting of satellite antenna scanning mechanism needs high stiffness and reliability. In this paper, the axial stiffness and radial stiffness of the shafting are calculated based on theoretical analysis, and the stiffness performance of the shafting is simulated and verified by finite element method. The results show that the relative error of radial stiffness and axial stiffness is 8.70% and 8.14% respectively. The calculation method adopted can effectively evaluate the stiffness performance of precision shafting and guide the optimal design of the shafting structure.
Finite element analysis of the reinforced concrete special-shaped columns under axial force and torsion
Authors: He Ye , Zhang Kui
Published: August 2020

The finite element analysis software ANSYS is used to analyze 9 reinforced concrete special-shaped columns under the combined action of axial force and torque. The parameters of the numerical model are given through repeated trial calculation. The influence of different values of axial compression ratio on the torsional capacity of test specimens is studied. The results show that the prediction error of the finite element model is small, which means the model is capable of accurate simulation. But the whole process analysis of the torque-torsion angle curve needs to be improved. The cracking and ultimate torque of special-shaped columns with different sizes and section shapes increase linearly with the growth of axial compression ratio. However when the ratio exceeds 0.6, the torsional bearing capacity of the columns will decrease. The increasing of axial compression ratio will also shorten the process from cracking to ultimate torque.
Prediction study of temperature deviations on left and right sides of power plant boiler reheaters based on regression algorithm learning machine and expert experience
Authors: Cui Yu-jia , Huang Ying , Ma Xiao-chun , Ma Guo-hang
Published: August 2020

Based on regression algorithm learning machine and expert experience, the temperature deviation prediction of the left and right sides of the power plant boiler reheater is based on real-time or off-line data collected by the power plant boiler. The data is divided by expert experience and algorithm processing data. Based on the machine learning regression algorithm, a regression algorithm learning machine is established. Through this learning machine and expert experience, the temperature deviation of the left and right sides of the power plant boiler reheater is predicted. The results show that the model can accurately predict the temperature deviation of, the left and right sides of the power plant boiler reheater, thus providing reference guidance for the operation of the power plant boiler.
Research on gear fault degree recognition method based on multi sensor fusion
Authors: Chen Xihui
Published: August 2020

The fatal fault of gear will inevitably experience the evolution of different fault degrees, and the accurate recognition of the fault degree of gear has more practical significance for predictive maintenance and efficient operation. A gear fault degree recognition method based on multi sensor fusion is proposed. Ensemble local mean decomposition (ELMD) is used to decompose the vibration signal of gear, which can eliminate the aliasing effect of LMD. Then, the fault feature is extracted by using envelope spectrum information entropy and time-domain kurtosis. Based on the initial recognition of the sub evidence formed by a signal sensor based on wavelet neural network (WNN), the basic belief function assignment and fusion methods of Dempster-Shafer (D-S) evidence theory are determined, and the accurate recognition based on multi sensor fusion for different fault degree of gear is realized, which is verified by experiments.
Research on establishment and verification of projectile and artillery coupling system virtual prototype
Authors: You Xuemin , Sun Yezun , Xu Xu , Li Bo , Yang Zhenqian , Liu Jiangong
Published: August 2020

A virtual prototype of a projectile and artillery coupling system was constructed and a virtual shooting test was performed. The virtual prototype of the projectile and artillery coupling system was verified by using key parameters when sitting behind the body tube. The results show that the projectile-artillery coupling model has good consistency with the actual mechanical system, which confirms that the virtual prototype of the projectile-artillery coupling system can basically reflect the dynamic characteristics of the artillery during launch.
Analysis of noise characteristics of spur face gear under different installation errors
Authors: Wang Yanzhong , Su Guoying
Published: August 2020

Face gear drives have been widely used in helicopter drive system, but there are few research literatures on meshing noise. In order to study the relationship between installation errors and gear meshing noise, the tooth surface equation of spur face gear is derived based on the principle of gear shaping; Based on the virtual meshing relative position of gear shaper, pinion and spur face gear, the control equation of installation distance between pinion and spur face gear is derived; Based on the method of orthogonal test, the noise test scheme with installation errors is set up, and the meshing noise characteristics of spur face gear are obtained. The research provides a theoretical basis for the development of noise reduction technology of spur face gears.
Dynamic performance of planar mechanism with joint clearance considering stochastic parameters
Authors: Lu Zhiqian , Zhang Li , Tao Junyong
Published: August 2020

Due to the influence of working temperature and pressure, collision restitution coefficient, Poisson’s ratio, friction coefficient and other material parameters could range in different intervals. However, the uncertainties and variability of material parameters is usually ignored in most researches. Along with vibration and wear, joint clearance is inevitable and widely exists in mechanical devices, which also should be taken into consideration. In this paper, the kinematic and dynamic equations are developed based on continuous Lankarani-Nikravesh contact model and the modified Coulomb friction model using a typical crank-slider mechanism as the research object. The influence of stochastic parameters (obeying normal distribution) on the dynamic characteristics of crank-slider mechanism is studied. In addition, dynamic analysis of the crank-slider mechanism with cylindrical joint clearance of different sizes is carried out in MATLAB environment. Results show that parameter random uncertainty should also be involved in dynamic models.
Study on fluidization process in jet flow dredging device and the effects of device structure to sand collecting performance
Authors: Zhang Yue , Song Jinchun
Published: August 2020

The device structure has important influence on the sand collecting performance of jet flow dredging device. In order to study the effects of device structure, this paper presents a research for fluidization process of compact packing sand in jet flow dredging device. The calculation method which considers the cohesive strength between particles is proposed. The effects of arrangement of jet pipe and diameter ratio between jet pipe and suction pipe on sand collecting performance are studied. By comparison, we found that the structure of jet pipe inside suction pipe has better sand collecting performance than it outside suction pipe. With the jet velocity increasing, the pipe diameter ratio corresponding to the maximum concentration of particle phase at outlet reduces.
A comparison of bending resistance of square thin-walled tubes with different internal reinforcements
Authors: Xie Zhongyou
Published: August 2020

Thin-walled structures with light weight are applied widely in some engineering fields, and thin-walled tubes are liable to local deformation under transverse loading. In the paper, six internal reinforced configurations of square thin-walled tubes were presented and their bending resistance was compared with each other based on finite element analysis by ABAQUS code. The numerical results reveal that the internal reinforcement plays significant role on the bending resistance, and some reinforcing strategies have evident advantage over the empty tube without any reinforcement considering the weight specific energy absorption. In addition, the reinforced configurations have more designability than the ordinary empty tube to obtain more specific energy-absorbing capacity.
Surface-process correlation for an ink-jet printed transparent fluoroplastic
Authors: Gomez Carlos , Campanelli Carlo , Su Rong , Leach Richard
Published: August 2020

Ink-jet printing is one of the key technologies in the field of defined polymer deposition. There is currently a lack of knowledge regarding how some fluoropolymers, in this case THV 221, can be ink-jet printed. A quantitative analysis of the micro-scale areal surface topography measured with coherence scanning interferometry can advance the understanding of the correlation between the ink-jet printing process and the resulting surface topography. Our experimental design covers a variety of ink-jet printed THV 221 structures with basic geometric shapes such as dots and films, ranging from a few nanometres to tens of micrometres in height, and from tens of micrometres to a few millimetres in spatial wavelength. Relevant printing parameters, including polymer concentration, drop spacing and number of layers have been selected and varied to produce the samples used for the study. This investigation also provides an insight into how to control and optimise the quality of THV 221 printed parts.
Telomere length and its relationships with lifestyle and behavioural factors: variations by sex and race/ethnicity
Authors: Vyas Chirag M , Ogata Soshiro , Reynolds Charles F , Mischoulon David , Chang Grace , Cook Nancy R , Manson JoAnn E , Crous-Bou Marta , De Vivo Immaculata , Okereke Olivia I
Published: August 2020

Background

Adherence to healthy lifestyles/behaviours promotes healthy ageing. However, little is known about whether age, sex and/or race/ethnicity moderate associations of lifestyle/behavioural factors with relative telomere length (RTL), a potential biomarker of ageing.

Methods

We included 749 midlife to older non-Hispanic White (n = 254), Black (n = 248) and Hispanic (n = 247) US participants [mean (standard deviation) age = 69.3 (7.2) years; women: 50.5%]. We extracted genomic DNA from peripheral leucocytes. RTL was assayed using real-time quantitative polymerase chain reaction. Multivariable regression was used to examine associations between lifestyle/behavioural exposures (i.e. physical activity, alcohol consumption, smoking and depression) with RTL.

Results

Increasing chronological age was associated with shorter RTL (P < 0.01). Higher physical activity was associated with longer RTL (P-trend = 0.03); daily versus never/rare alcohol consumption and 30+ versus <5 smoking pack-year were associated with shorter RTLs (P-trend = 0.02). Associations varied significantly by sex and race/ethnicity. The association between physical activity and longer RTL appeared strongest among non-Hispanic Whites (P-interaction = 0.01). Compared to men, women had stronger associations between heavy smoking and shorter RTLs (P-interaction = 0.03). Light/moderate alcohol consumption (monthly/weekly) was associated with longer RTL among non-Hispanic Whites, while daily consumption was related to shorter RTLs among Blacks and Hispanics (P-interactions < 0.01). Associations of daily alcohol and heavy smoking with shorter RTLs were particularly apparent among Black women.

Conclusion

We observed novel variations by sex and race/ethnicity in associations between lifestyle/behavioural factors and RTL. Further work is needed to replicate these findings and to address potential public health implications for modifying strategies by sex or across racial/ethnic groups to optimise lifestyles/behaviours for healthy ageing.
The Utility of Spot vs 24-Hour Urine Samples for Metal Determination in Veterans With Retained Fragments
Authors: Gaitens Joanna M , Brown Clayton H , Strathmann Frederick G , Xu Hanna , Lewin-Smith Michael R , Velez-Quinones Maria A , McDiarmid Melissa A
Published: August 2020

Objectives

The objective of this investigation is to explore the utility of using a spot urine sample in lieu of a 24-hour collection in assessing fragment-related metal exposure in war-injured veterans.

Methods

Twenty-four veterans collected each urine void over a 24-hour period in separate containers. Concentrations of 13 metals were measured in each void and in a pooled 24-hour sample using inductively coupled plasma mass spectrometry. To assess the reliability of spot sample measures over time, intraclass correlations (ICCs) were calculated across all spot samples. Lin’s concordance correlation coefficient was used to assess agreement between a randomly selected spot urine sample and each corresponding 24-hour sample.

Results

In total, 149 spot urine samples were collected. Ten of the 13 metals measured had ICCs more than 0.4, suggesting “fair to good” reliability. Concordance coefficients were more than 0.4 for all metals, suggesting “moderate” agreement between spot and 24-hour concentrations, and more than 0.6 for seven of the 13 metals, suggesting “good” agreement.

Conclusions

Our fair to good reliability findings, for most metals investigated, and moderate to good agreement findings for all metals, across the range of concentrations observed here, suggest the utility of spot urine samples to obtain valid estimates of exposure in the longitudinal surveillance of metal-exposed populations.