bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Frictional Force between Lining Concrete and Rubber Blocks
Authors: Zhou Zhiyong , Gao Sen , Chen Xiaolu , Guan Chengying
Published: September 2021

This paper mainly studies the friction coefficient between lined concrete and rubber blocks, designs the Friction resistance test device, puts forward two different Shaw hardness rubber blocks in different environments, and carries out the experimental research, obtains the corresponding coefficient of friction results, and provides the parameters and basis for the development of the special enclosure for the research of the subject.
Experimental study on particle breakage and fractal characteristics of coarse-grained soil
Authors: Jun Du , Xing-gang Shen
Published: September 2021

Particle breakage is an important factor affecting the strength and deformation of coarse-grained soil. In order to study the compaction characteristics and particle breakage effect of coarse-grained soil, the compaction tests of coarse-grained soil with different stone content and water content were designed. The results show that the dry density of coarse-grained soil first increases and then decreases with the increase of water content. With the increase of stone content, the maximum dry density and optimal moisture content of coarse-grained soil increase. After compaction test, the coarse-grained soil has obvious particle breakage phenomenon, and the particle breakage index increases with the increase of stone content and water content. The fractal dimension D can characterize the coarse-grained content of coarse-grained soil. With the increase of coarse-grained content, the fractal dimension D decreases gradually.
Application of non-destructive testing technology in construction steel structure industry
Authors: Wei Han , Lina Liu
Published: September 2021

High-rise buildings are mostly made of steel structures, and the damage detection technology for the welding process of steel structures still needs to be improved. Especially in the current welding process, there are problems such as the lack of data-based control mechanism and the uneven quality of the staff. The use of non-destructive testing technology can effectively detect defects in the welding process, while ensuring the quality of use of the steel structure. This article will study the application of non-destructive testing technology in steel structures, and provide some opinions and suggestions on the development of the construction steel structure industry by analyzing the problems that occur in the welding process.
Calculation on Short-term Stiffness of Simply-supported Beams with Gradient Concrete and Glass Fiber Reinforced Plastic Bars
Authors: Yao Lirong , Zhao Deyin , Zhong Rongqiang , Guo jing , Li Zhiming
Published: September 2021

It is of the advantages of high bearing capacity and economy for the gradient concrete beam with glass fiber reinforced plastic(GFRP) bars, so it will be applied widely in practical engineering. In order to acquire the short-term stiffness of simply-supported beams with gradient concrete and GFRP bars, 14 simply-supported beams were designed. Based on material constitutive model, finite element models of the beams are established by ABAQUS software. The stiffness variation law of the specimens is acquired. The simulation results are in good agreement with the experimental results, which proves the correctness of finite element modeling. Based on numerical simulation the stiffness calculation formula of the beams is provided, which can provide reference for the application of the beams in the actual engineering.
Study on the effect of ion invasion on compressive strength, resistivity and polarizability of concrete
Authors: Lu Si Tong , Huang Jun Ge , Zhang Yu
Published: September 2021

The structural safety of concrete has been attached great importance, especially in saline-alkali area. In order to better study the changes of physical parameters of concrete after corrosion in saline-alkali area, the soil quality in saline-alkali area was investigated and sampled to analyze the main ionic components of concrete corrosion environment. According to the corrosion ionic components, the concrete model was made by mixing carbonate and sulfate solutions with different concentrations. Resistivity method and induced polarization method were used to measure the resistivity and polarizability characterization of the model within the curing period (28d), and the compressive strength of the concrete model during the curing period was tested to study the correlation between the resistivity, polarizability and compressive strength of the concrete model. The results show that the resistivity, polarizability and compressive strength of concrete are closely related to the type and concentration of ions. There is a corresponding relationship between the polarizability and the bearing capacity of concrete test blocks mixed with the same solution. The larger the polarizability, the weaker the bearing capacity. There is no strong correlation between resistivity and bearing capacity. Polarizability data can reflect both ion invasion and strength change of concrete.
Effects of AlN and rare earth fluorides on the thermal conductivity of SiC ceramics with impedance spectroscopy analysis
Authors: Li Jingren , Lu Wenzhong
Published: September 2021

Dense silicon carbide (SiC) ceramics were fabricated through hot-pressing with an innovative additive combination of AlN and rare earth fluorides (ReF3, Re= La, Nd and Gd). Effects of these additives on the microstructure, phase composition and thermal conductivity of SiC ceramics were evaluated. All samples showed compact microstructures, high densities and clean grain boundaries without visible secondary phases. Sample sintered with 4 wt%AlN and 1 wt%NdF3 (4A1Nd sample) exhibited the highest thermal conductivity (152.3W/m·K) amongst all. Impedance spectroscopy analysis was employed to associate with the thermal conductivity variations in different samples by analyzing defects and impurities. 4A1Nd sample exhibited the highest fitting grain and grain boundary resistances among all samples, indicated its lowest concentration of

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vacancies and impurities, which suggested the best impurity purifying ability of AlN and NdF3 combination. On the contrary, the sample sintered with 4 wt%AlN (4A sample) exhibited a higher concentration of defects than other ReF3 added samples. Therefore, the AlN-ReF3 additive combinations are promising in both tailoring and improving the thermal conductivity of SiC ceramics.
Nonequilibrium behavior of polymer nano films cast from different solvents
Authors: Fan Xiao , Ma Jinghong , Ma Yu
Published: September 2021

Properties of materials are largely determined by the processing conditions. This is especially true of polymers, which typically have much longer relaxation times than processing times and therefore possess out-of-equilibrium chain conformations. Here, we demonstrate that the nonequilibrium behavior of polymer nano films can be tuned by controlling the processing pathways. Films cast from different quality of solvents were aged at room temperature for various times, and then carried out the dewetting experiment above the glass transition temperature. The residual stress and relaxation time strongly depend on the quality of the solvents, and the differences may be caused by the boiling point and interaction parameter. This work offered a pathway for preparing a stable nano film, which is crucial for the durability of nanomaterials and devices.
Catalytic reduction of 4-Nitrophenol using CoPt nanoparticles on the reduced graphene oxide layer nanocomposite catalyst
Authors: Zhang Xiaolong , Duan Qian
Published: September 2021

The reduced graphene oxide (rGO) supported CoPt nanoparticles nanocomposite catalyst has been preparation by a facile method. The XRD and TEM results show that the CoPt nanoparticles were successfully loaded onto the rGO layer. The apparent rate constant (k) is about 0.167 min-1. The rGO/CoPt nanocomposite catalyst exhibits excellent catalytic performance for catalytic reduction of 4-nitrophenol. Moreover, the magnetic result shows that the rGO/CoPt nanocomposite is superpara-magnetism.
Controllable plasmonic nanostructures induced by ultraviolet laser
Authors: Li Dongfang , Yuan Yanping , Wang Chunlian , Chen Jimin
Published: September 2021

The plasmonic resonance express as strong extinction band and great enhancement of the electromagnetic field in the vicinity of the nanoparticles, which have been exploited in various applications such as data storage, super-resolution imaging, light collimation, solar cells, biosensors and absorbers. However, a simple and effective route to obtain uniform metal nanoparticles is still a challenge. Here, we have demonstrated a cost-efficient, lithography-free, and facile methods to obtain controllable gold nanoparticles (GNPs) for structure color by direct ultraviolet (UV) laser writing. The thermals dewetting process realized by UV laser direct writing, greatly simplifies the manufacturing process of plasmonic nanoparticles, lowers the bar for equipment, and realizes the structure color in selected areas. The direct laser writing process is performed on a 4 nm-thin island-like Au films atop dielectric-metal sandwiches. By local laser heating, the semi-continue gold film merges and reshapes into approximately spherical structure, generating brand colors. The structure color changes as a function of the laser energy density, low laser energy density to green and high laser energy density to red. Especially for lager laser energy density, the processed area shows a high saturation Numerical simulations confirm that the reflectance of the processed area is strongly affected by the absorption of the bottom metal layer and the local surface plasmon resonance of the top GNPs. In addition, the top GNPs play a major role in tunning the peak of reflection spectrum.
An Exploration on Mechanisms of Andrographolide Nanoemulsifying in Treating Gastric Cancer Based on Network Pharmacology
Authors: Chen Ting , Huang Xulong , Zheng Kaimin , Zhong Jinping , Huang Bin
Published: September 2021

This article preliminarily revealed the mechanism of andrographolide (AD) nanoemulsifying inhibiting gastric cancer(GC). The targets of AD was searched by TCMSP and SwissTargetPrediction database, we entered the keyword “Gastric Cancer” in GeneCards database to find all targets related to GC. The intersection of AD and GC is taken as an important targets for AD to act on GC, Cytoscape 3.7.1 was used for topological analysis of the target, so as to obtain all important targets for AD to inhibit GC. DAVID database was used to perform biological process analysis on all potential targets, mainly through its analysis function. It involves Cell composition, molecular function and signal pathway enrichment analysis. Finally, we obtained a total of 53 potential targets related to GC, among which IL6, MAPK8, CREBBP, CDK2, MAPK14, AR and MAP2K1 may be important targets for inhibiting GC. The effect of AD on GC is mainly through Influenza A, Pathways in cancer, Sphingolipid signaling pathway, Progesterone-mediated oocyte maturation, Herpes simplex infection and other important pathways which are closely related to 10 biological processes such as protein phosphorylation, signal transduction, peptidyl-serine phosphorylation, positive regulation of gene expression, and positive regulation of transcription from RNA polymerase II promoter Sex. This study can provide guidance for the development of anti-GC drugs.
The elastic modulus reduction method for upper bound limit analysis of pressure vessels incorporating material strain hardening effect
Authors: Zhang Yang , Liu Jingmin , Yang Yanyan
Published: September 2021

Pressure vessel is a kind of special equipment which is involved in various industries. Once it is damaged, it will cause great loss to people’s life and property. The traditional elastic modulus reduction method for upper bound limit analysis of pressure vessels adopts the elastic-perfectly plastic material model. This method will result in waste of materials without considering the material strain hardening effect. So the material strain hardening effect is introduced into upper bound limit analysis. Firstly, the equivalent yield strength considering material strain hardening effect is established. Then, the formula of limit load multiplier which is expressed by the equivalent yield strength is derived based on the upper bound theorem. Combined with the strategy for elastic modulus adjustment, the elastic modulus reduction method for upper bound limit analysis of pressure vessels incorporating material strain hardening effect is constructed. The limitation of the elastic-perfectly plastic model for the upper bound analysis method is eliminated by the method proposed in this paper. The result calculated by this method is closer to the true limit load of pressure vessels.
Changes in the Spectral Characteristics of Hydrophilic Fraction in Compost Organic Matter
Authors: Zilong Zhang , Yu Xiao
Published: September 2021

The hydrophilic fraction (HyI) is one of the important components of humus, and its structure and composition are important factors for evaluating the stability and maturity of compost. This study used spectroscopy to analyze the composition and structure of HyI. The results showed that with the passage of composting time, the UV–Vis curve had a red shift, indicating that the conjugated structure of the substance increased and the aromaticity is enhanced. The three-dimensional fluorescence excitation–emission spectrum (3D-EEM) showed that the fluorescence intensity of humus-like substances in HYI was significantly enhanced, and microbial metabolites such as protein-like substances, carbohydrates and other small molecules were continuously degraded, and the relative content decreased from 21% to 8%, the humus-like substances rose from 54% to 68%, which showed that the organic matter in the compost is continuously condensing and polymerizing, and the maturity and stability of the compost product are deepened.
Parameters Extraction Methods of Compound Semiconductor Photovoltaic Modules
Authors: Zhou Chuxiang , Wang Yu , Xu Jie
Published: September 2021

The parameters extraction method of the single diode model is usually used to analyse silicon-based solar cells to predict their behaviour from IV curves. However, the film solar cells based on compound semiconductor, for example the CdTe and CIGS, which have been widely used in the market, have few relevant studies still now. This paper presents two parameters extraction methods and applies to two photovoltaic modules, then we use a function in MATLAB to refine the results. Finally, the error of the two methods has been compared to find the best fitting result. Final fitting results show that these methods have their own advantages and disadvantages and both have great fitting accuracy on the two modules, and they can be used in various irradiance conditions.
Study on the characteristics of V2O5-WO3/TiO2 denitration catalyzer synergistic mercury removal
Authors: Zhiyong LU , Litao QU
Published: September 2021

Ti-V1W9 catalyzer obtained the best 68.18 % elemental mercury (Hg0) oxidation efficiency at the temperature of 250 °C, The elemental mercury (Hg0) oxidation efficiency can be maintained above 60 % in the reaction temperature range of 250-350 °C, indicating that V2O5-WO3/TiO2catalyzer has certain oxidizing ability to elemental mercury (Hg0); SO2 inhibits Ti-V1W9catalyzer’s ability to oxidize elemental mercury (Hg0), and the toxicity of Ti-V1W9 catalyzer cannot be reversed to some extent; O2 has a very obvious promoting effect on the oxidation performance of Ti-V1W9catalyzerelemental mercury(Hg0). Increasing the concentration of O2 can significantly improve the elemental mercury(Hg0) oxidation efficiency; Low concentration of NO contributes to the adsorption oxidation of elemental mercury (Hg0) by Ti-V1W9 catalyzer, while high concentration of NO significantly inhibits oxidation of elemental mercury (Hg0); NH3 inhibits the adsorption and oxidation of elemental mercury (Hg0) on the surface of catalyst; H2O(g) has very obvious inhibitory effect on elemental mercury (Hg0) adsorption oxidation.
Three-layer structure hot bending/diffusion bonding process of reactive sintering Ti-22Al-25Nb alloy and its load response at high temperature
Authors: Long-hai YU , Yuan-xin Wang
Published: September 2021

Three-layer structure part as a ideal structure part, that had light weight and enough strength to be widely used, was prepared combining hot bending and diffusion bonding processes in this paper. The Ti-22Al-25Nb sintered alloy that owned better using temperature was applied to manufacture three-layer structure part. The forming processes of manufacturing three-layer structure was divided into hot bending forming of the core sheet and diffusion bonding of three layers sheets. Firstly, the hot bending of core sheet was performed at 1423K for 10MPa in a vacuum furnace. Secondly, the diffusion bonding of three layers sheets was carried out at 1473K for 120min and 10MPa. Furthermore, in order to evaluate the quality and performances of three-layer structure, the microstructure of bonding joint of three layers sheets was analyzed by SEM, and the properties of three-layer structure part were tested at 1073K by compressing test and three-point bending test. Compressing load and compressing strength were 9014N and 10MPa, respectively. Bending strength was up to 54MPa. In addition, the experimental results also indicated that three-layer structure that prepared using the Ti-22Al-25Nb sintered alloy owned good properties.
Study of structure and electrochemical properties of Fe-doped carbon aerogels
Authors: Wang Shasha , Ren Bin , Zhang Lihui , Liu Zhenfa
Published: September 2021

A nanocomposite material CAFe was obtained by assembling of Fe and carbon aerogels. The physical characterizations of CAFe were compared using XRD, Raman, XPS, and SEM. The results showed that Fe was successfully loaded onto carbon aerogels. The results of the electrochemical performance revealed CAFe exhibited high specific capacitance (78.7 F g-1) and excellent stability. Therefore, Fe-doped carbon aerogel is a good electrode material.
Research on capacity degradation and aging state estimation of lithium-ion battery
Authors: Li Xu , Zhang Qi , Yang Bowen , Wang Dafang , Cui Shengmin
Published: September 2021

The aging state estimation of the power battery is very important for the battery management system (BMS). Regular estimation of the battery’ state of health (SOH) can improve the service life of electric vehicles. The reasons for the aging of lithium-ion battery are briefly introduced in this paper. What’s more, the estimation methods of battery aging state are summarized and described from both the model-based and data-driven aspects.
Properties of carbon-doped GaN using isobutane as a dopant
Authors: Li Xun , Zhu Songran
Published: September 2021

Carbon doping is an effective method to obtain semi-insulating GaN buffer, which is a necessity to prevent current leakage, in the high-electron-mobility-transistor device structure. The properties of intentionally carbon-doped GaN using isobutane gas as a dopant has been studied in detail. The carbon incorporation efficiency has been measured by secondary ion mass spectrometry. It is found that the carbon concentration could be directly controlled by the flow rate of isobutane precursor. The surface morphology of carbon-doped gallium nitride epitaxial layers has been investigated by optical microscopy and atomic force microscopy. The growth mode of GaN layers changes from step-flow to island growth, when the incorporated carbon concentration is higher than 1×1019 cm-3. In order to evaluate the structural quality of intentionally carbon-doped GaN, the full-width-at-half-maximum values are extracted from the rocking curves in six different reflections measured by high resolution X-ray diffraction. Raman spectroscopy is utilized to evaluate the physical properties of the carbon-doped GaN epitaxial layer.
Research on the Anode Protection of Lithium
Authors: Tao Chen , Jingze Li , Hongli Liu , Jianjian Shi
Published: September 2021

The anode of Lithium serves as the most ideal substitute for graphite anode. However, uncontrolled growth of lithium dendrite brings about service life and safety problems, which limit its commercial application. According to the thermodynamic and kinetic factors of lithium dendrite growth, many strategies have been proposed to inhibit the growth of lithium dendrite, such as structural composite lithium metal anode, optimizing SEI film, using solid electrolyte, etc. This paper reviewed the development process of different strategies, and analyzed their advantages and limitations, looking forward to the possible direction of inhibiting the growth of lithium dendrite.
The photoelectric conversion enhancement of p-Cu2O/n-ZnO heterojunction by deposition temperature
Authors: Niu Jingjing , Pan Jiaqi , Fu Wendi , Li Chaorong
Published: September 2021

Dense ZnO films were prepared by RF magnetron sputtering, and PN junctions were formed with Cu2O films prepared at different deposition temperatures. Different characterization methods show that the PN junction has better transmittance. Compared with the unheated Cu2O, the Cu2O / ZnO PN junction formed by the heated Cu2O film shows obvious enhancement of photoelectric properties, which can be attributed to that the improved film crystallinity with the increased sputtering substrate temperature, can reduce the corresponding defects in the film.
Hyper-spectral Imaging Technology Based on Linear Gradient Bandpass Filter for Electricity Power Equipment Status Monitoring Application
Authors: Cheng Li , Ziwen Shang , Minzhen Wang , Li Liu , Guangxin Zhang , Jian Zhang , Liyin Zhao , Xiao Zhang , Hongxia Ni , Dongliang Qiao
Published: September 2021

Hyperspectral imaging technology has been applied to the status monitoring of power transmission line and equipment as its continuous and narrow-band induction characteristics, which provides a solution for the operation monitoring of lossless large-area power equipment. However, the optical and electronic equipment is complex, and the related products are large and expensive on the market. This paper describes a preparation method of a linear gradient filter that is cost performance and miniaturization, which can be used to realize the prototype hyper-spectral imaging camera. The high precision preparation process and principle make the camera show good spectral performance, which can scan with precision step length of 2nm between 400nm and 1000nm. The feature extraction and classification algorithm can be used to determine the health conditions of power equipment, such as partial discharge, with an accuracy of about 77%. The equipment collocation algorithm can also be used to identify defects in power equipment, which has been proved to be able to distinguish between aging insulators, icing of conductors and heating of wire clips. This method are promising for an entry-level, low-cost hyper-spectral imaging solution for power detection applications.
Interlayer ferromagnetic coupling and enhanced magnetism by biaxial strain in MnBi2Te4/VBi2Te4 heterojunction
Authors: Wu Zebin , Song Changsheng , Li Chaorong
Published: September 2021

The pristine anti-ferromagnetic interlayer coupling of even layers MnBi2Te4 greatly restricts the possibility of realizing quantum anomalous Hall (QAH) effect. In this work, based on first-principles calculations, we find that the interlayer coupling can be transformed into ferromagnetic order from anti-ferromagnetic by substituting cations with V atoms. Furthermore, when applying biaxial strain, a strong band inversion occurs around Fermi level, achieving quantum anomalous Hall effect. A gapless surface states can further confirm it. Meanwhile, the magnetic moment of Mn and V atoms increases with the increase of strain. We attribute this to the electron hopping to magnetic atoms from p orbitals of nonmagnetic Bi and Te atoms. Our work extends the range for designing and applying for spintronic devices with QAH effect.
Effects of different solvents on ultraviolet absorption and fluorescence intensity of 2,4-dichlorophenol, 2,4,6-trichlorophenol and Pentachlorophenol
Authors: Lan Wenbo , Li Qianru , Wang Xiaofeng , He Liping , Meng Yanbin , Wang Yashi , Li Jianhuang , Zeng Can , Wang Liying , Luo Mengfen , Bu Zhijian
Published: September 2021

In order to study the influence of the UV-visible absorption spectra and fluorescence spectrum from 2,4-dichlorophenol (2,4-dcp), 2,4,6-trichlorophenol (2,4,6-tcp) and pentachlorophenol (ptcp) in different solvents. Using methanol, tetrahydrofuran (THF), ethanol, dimethyl sulfoxide (DMSO) and acetone solvent models, computer simulation prediction and analysis of the three chlorophenols were carried out. It provides a reference for the choice of solvents in the determination of chlorophenols by the Ultraviolet-Vis absorption spectrophotometry and fluorescence intensity detection.
Motion of a self-propelled rod with Brownian and hydrodynamics interactions
Authors: Hu Nannan , Ma Fu , Wang Yaohong
Published: September 2021

The dynamic behaviour of a self-propelled rod in a three-dimensional system with cut-and-shifted Lennard-Jones interaction is studied by stochastic Eulerian Lagrangian method which coupled the coarse-grained microstructure degrees of freedom to continuum stochastic field, and the relaxation and thermal fluctuation of the fluid dynamics mode are taken into account. The diffusion of the self-propelled rod is found to have four regimes. The distributions of the horizontal displacements tend to bimodal non-Gaussian at long time when the self-propelled forces are introduced. Furthermore, we study the distributions of the rod velocities in parallel and perpendicular to the rod axis in the body frame. They are all Gaussian, and their standard deviations increase when the self-propelled forces increase.
Data-driven Modeling of Chinese Gong Based on Sparse Identification of Nonlinear Dynamics
Authors: Zhang Qinghong
Published: September 2021

Gong is widely employed in Chinese folk bands, but its sound mechanism and mathematical model is still not fully resolved. This work employs MEMS gyroscope to collect the vibration angular rate of two types of Hand Gong including median pitch and high pitch Gongs. This paper further employs Sparse Nonlinear Dynamics Identification (SINDy) [1] to identify a reduced order model of Gong. The model is using angular velocity as state variable and candidate library of nonlinearity is chosen up to fifth-order polynomial. The results indicate that the nonlinearity is prominent up to the third order (cubic) and the cubic nonlinearity is not appearing for the rotation around the axis perpendicular to Gong surface. These results confirm previous observations that the oscillator with a cubic nonlinearity is able to well characterize the nonlinear vibration behavior of Gong [2]. One potential application of this work is on musical psychology.
Research on Heat Dissipation and Insulation Measures of a Prestressed Continuous Box Girder Bridge Section
Authors: Wang Runjian
Published: September 2021

Taking a prestressed concrete box girder as the research object, aiming at the problem that the concrete bridge durability is reduced due to the appearance of temperature cracks in the concrete box girder, this paper adopted different types of heat insulation materials, and theoretically analyzed the structural temperature field of concrete box girder under high temperature difference and low temperature environment from the aspects of whether the heat source was set inside the concrete box girder, which provides a reference for the technical application and promotion of thermal insulation materials in concrete bridges.
Flexible Application of Static Balance Principle in Beam Internal Force Diagram
Authors: Ting Kang , Yingsheng Bai , Erlei Bai , Huixiang Sun , Tao Ge
Published: September 2021

When using the conventional segmental superposition method to make the bending moment diagram, it is not only complicated to calculate, but also easy to make mistakes. In this paper, it is discussed how to flexibly segment and simplify the calculation with examples. At the same time, according to the differential relationship, integral relationship and static equilibrium conditions between load and shear force, the fast and accurate pithy formula for shear force diagram making is concluded. The deep application of integral relationship between load and shear force is also discussed.
General Calculation Method of Normal Stress on Cross Section of Combined Tension (Compression) Bending Deformation
Authors: Wu Mengmeng , Yang Shaohong , Deng Hui
Published: September 2021

Tension (compression) bending combined deformation is a commonly used combined deformation form in engineering. The current material mechanics textbooks use the superposition method to calculate the stress on the cross section of the combined deformed member, whose characteristics are simple and easy to grasp. However, the premise of superposition principle is that the internal force, stress, strain and displacement have a linear relationship with external force. If the above linear relationship cannot be guaranteed, the superposition principle cannot be applied. In this case, the stress-strain relationship must be used for calculation. Based on the assumption of plane and unidirectional force, in this paper, rods with arbitrary cross-sectional shape under arbitrary load were taken as the research object, and the general calculation methods of the stress on the cross-section during the combined deformation of tension and bending were studied. This paper aimed at expanding students’ thinking mode and improving students’ learning ability in the process of material mechanics teaching.
Recent advances in active and passive microfluidic sorters
Authors: Wang Haoran
Published: September 2021

Due to the fast development in biology and chemistry, scientists find that it is important to get a suitable sorter since it can enhance the accuracy and speed of the cell sorting application. For instance, researchers in the biological field need precise sorters to help them separate different kinds of components. The need for micro-fluidic based sorting, a useful technique in medicine or biology, has promoted the development of microscale sorters. This paper reviews two types of sorters, including active and passive sorters. The principles, mechanisms, merits and demerits, avenues for improvement, and application in the future of those two sorters are summarized. In conclusion, this paper could be a useful reference for those who would like to know the microfluidic sorter’s overall knowledge.
Effect of low velocity impact on residual compressive strength of stiffened panel with welding residual stress
Authors: Liu Hui , Lei Zhenkun , Guo Zhenfei , Jiang Hao , Bai Ruixiang
Published: September 2021

Al-Li alloy stiffened panel is the main structural form of aircraft fuselage. Laser welding will produce welding deformation and residual stress, on the other hand, low velocity impact will also affect the residual bearing capacity of stiffened panel structure. In this study, the nonlinear finite element (FE) method is used to simulate the laser welding process of stiffened panel, and the welding residual stress is directly introduced into the subsequent impact after compression (CAI) process of stiffened panel. The effects of different impact positions and different impact energy on the residual CAI strength of stiffened panel are studied. The results show that the impact damage has the greatest effect on the residual compressive strength of stiffened panel when the punch impacts the stiffener, and the greater the impact energy is, the greater the influence is.
A Real-time Dynamic Deflection Measurement Method using Dual Camera for Lifting Device Dynamic and Static Load Test
Authors: Tang Xiaojun , Han Jingzhen , Yu Juan , Li Haixia
Published: September 2021

In the process of deflection measurement for lifting device dynamic and static load test (DSLT), the traditional measurement method has some obvious problems, such as complex test process, slow measurement speed, poor accuracy, low efficiency, and difficult dynamic measurement. Therefore, a real-time binocular vision method for measuring deflection in the lifting device DSLT is proposed. The results of verification show that the method can realize the real-time and fast deflection measurement in the lifting device DSLT, and has the advantages of non-contact, high precision and dynamic measurement. Compared with the traditional methods, the method proposed in this paper is simple, universal and easy to implement.
Study on the Influence of Isolated Roughness on Hypersonic Flow over Blunt Wedge
Authors: Tang Xiaojun , Han Jingzhen , Shi Mingfang , Yu Juan
Published: September 2021

To investigate the problem of the influence of the depth of the isolated D-type roughness element on the hypersonic flow around the blunt wedge boundary, the high-order accuracy finite difference method is used to carry out the direct numerical simulation, the influence of the depth of the isolated D-type roughness element on the interaction between the free flow and the wall is analysed, and the influence of the D-type roughness element on the wall pressure, the wall friction resistance and the wall heat flow is discussed. The results show that the strength of compression wave and expansion wave increases with the increase of the depth of D-type roughness element, but the position of compression wave and expansion wave does not change; With the increase of the depth of the D-type element, the change speed of the flow parameters will be accelerated, the peak value will increase and the trough value will decrease, and the position of the peak and trough will gradually move away from the center of the element with the increase of the depth of the element. When the depth of the D-type element is greater than or equal to 0.08, a vortex will form in the D-type element, and the length of the vortex increases with the deepening of the element. The D-type element will not change the flow state of the shear layer near it.
Modified engineering method for ultimate load prediction of composite hat-stiffened panels
Authors: Huang Xiaodi , Bai Ruixiang , Liu Wenhao , Wang Tao
Published: September 2021

In this paper, the ultimate load of a typical hat type composite stiffened panel under axial compression is simulated by finite element method. Based on the ultimate load value and failure mode obtained by numerical simulation, the thickness of the lower flange of the stiffener in the engineering method is modified by using the stiffness equivalent method. The modified engineering method is in good agreement with the finite element results, which has a certain reference significance for the rapid calculation and analysis of stiffened plate in the early design stage.
Study on Calculation Method of Anti Overturning of Continuous Steel Box Girder
Authors: Qi Zhongyang , Huang Fang , Su Xingju , Wang Shuang
Published: September 2021

The self weight of steel box girder is light, and the stability effect is smaller than that of concrete bridge. In this paper, the anti overturning research of the main line bridge and ramp bridge is carried out. It is found that for the variable cross-section continuous beam bridge with wind barrier along the whole line, when the pressure reserve of the side pier is small under the action of self weight, the compression of the bearing under the action of basic combination can not ensure that the bearing will not be empty under the action of standard value combination; Centrifugal force, wind load and temperature load caused by vehicle load have great influence on bridge overturning, which can not be ignored; Temperature load and foundation displacement may lead to stability or instability according to the stiffness distribution of the main beam. In this paper, it is proposed that both the basic combination and the standard value combination should be considered when checking the bearing void. It is recommended to adopt the calculation method of “the stability effect is the standard value effect that makes the superstructure stable, and the instability effect is the standard value effect that makes the superstructure unstable” as the stability coefficient.
The Profile of A Thin Piece of Paper with Both Ends Fixed
Authors: Chen Xuyang
Published: September 2021

In this manuscript, utilizing the controlled variable method, the three different profiles of thin paper with fixed ends are investigated. The results indicate that the specific profile of the paper depends on the length of the paper and the fixed distance between the sheets. Meanwhile, the mass of the paper has little effect on its profiles and so it can be ignored. Also, the symmetry-broken phenomenon about the thin paper is observed. Finally, according to the Principle of Least Action, it proposes a simple model to simulate the thin paper profiles
The Midpoint Upwind Scheme on the Bakhvalov-Shishkin Mesh for Parabolic Singularly Perturbed Problems
Authors: Zheng Quan , Wang Yi-Yang
Published: September 2021

In this paper, the parabolic singularly perturbed convection-diffusion problem is discretized by using the backward Euler method in time and the midpoint upwind scheme on the Bakhvalov-Shishkin mesh in space. This method is shown to be first-order convergent in time and space. Finally numerical experiments confirm the theoretical results.
Dynamic numerical simulation analysis of a large caliber artillery projectile extrusion process
Authors: Zhang Xin , Wang Baobao , Zhang Hui , Yu Cungui
Published: September 2021

Taking a large-caliber gun as the research object, a projectile and gun coupling finite element numerical simulation model during the extrusion process is established according to the finite element simulation technology. The dynamic simulation of the extrusion process is carried out by using ABAQUS/EXPLAICT solver, and the stress variation law of the projectile belt during the groove and the barrel during the extrusion process is obtained. In the post-processing module of the finite element software, the data of displacement, velocity and acceleration at the center of mass of the projectile in the extrusion process are extracted, and the motion law of the projectile in the extrusion process is analyzed, which provides some reference value for the study of the extrusion process of large caliber artillery projectile.
Positive definite matrix and its proof method
Authors: Jiang Yinshan
Published: September 2021

Advanced algebra is a required course of undergraduate mathematics, which plays a fundamental role in completing the study of other professional courses for students. Matrix theory is an important branch of mathematics, it is not only a basic subject, but also themost practical value. Widely used in mathematical theory, matrix is an important basic concept in matrix theory, is a major study of algebra, Positive definite matrix is a kind of important matrix, occupies an important position in “higher algebra”, its theory has rich content, positive definite quadratic form and Euclidean space, physics, probability and optimization control theory are related to it.
The Fourier Transform and its application in solving the equation
Authors: Guan Hanwen , Song Haoyi , Yang Yukun , Zhang Jiayuan
Published: September 2021

Fourier transform is a linear transform that applicants in the field of engineering and physics. In this research study, we summarize the fundamental properties of the Fourier transform and its application in solving the wave equation. First, we review the definition of Fourier transform and its inverse form. Then, we show Schwartz space is the invariant subspace of the Fourier transform. We also prove the Plancherel theorem. At last, we apply the Fourier transform to solve the wave equation.
Three methods for solving systems of linear equations: Comparing the advantages and disadvantages
Authors: Luo Haoyu , Wu Simeng , Xie Ningyun
Published: September 2021

This paper aims to introduce some prevalent techniques which have been used to solve linear systems. Firstly, we introduce the simplest method: how to eliminate variables in which the original systems would not be changed. We then introduce Gaussian eliminations, which work on the augmented matrix derived from a linear system. To the end, we present Cramer’s rule, which computes the solution to a linear system based on matrix determinants. These methods have their application scenarios. For instance, eliminating variables has no limited condition for its operations. However, Cramer’s rule needs to be under the condition of square matrices. At the same time, Gaussian elimination requires three elementary row operations, and Gaussian elimination paves the way for computing the rank of matrices. The choice between these methods depends on coefficient matrices in terms of dimensions and matrix properties such as singularity.
RESEARCH ON COVID-19 EPIDEMIC BASED ON ARIMA MODEL
Authors: Zhihao Li , Junpei Wang , Xiaoliang Zhang , Huijun Ning
Published: September 2021

Since the outbreak of the novel coronavirus, the epidemic has received extensive attention all over the world. In this article, an evaluation system was established to analyze the epidemic prevention and control situation of some countries. And the ARIMA model was built to predict the epidemic situation in a short period of time. Then taking the United States as an example, the predicted values of the number of newly diagnosed cases, death rate, and cure rate in 10 days were obtained, which were then compared with the actual data. It is shown from the results that the ARIMA model can be used to predict the epidemic and provide a decision-making basis for the current world’s epidemic prevention and control.
Soliton solutions of a generalized Gross-Pitaevskii equation via Darboux transform
Authors: Liu Shuli , Wang Dan , Geng Yong , Wang Xiaoli
Published: September 2021

The nonlinear Schrödinger equation (NLS) is widely used in different branches of physics. The GP equation is a kind of NLS equation with potential function term. In this paper, the soliton solutions of a generalized GP equation are explored. Firstly, we construct the Lax pair and Darboux transform(DT) of the equation. Then, we solve the single and double soliton solutions of the equation. Lastly, we draw the images of the single and double soliton solutions, and investigate the properties of the solitons. It is found that the amplitude of a single solitary wave does not change, and the shape and amplitude of the double solitary wave remain unchanged after the collision.
Form-finding Design of Cable Network Antenna with Truss System by Force Density Method
Authors: Wang Lipeng , Xiao Yong , Yang Jungang , Fu Kangjia
Published: September 2021

In recent years, the design and development of space-borne large-scale deployable antennas represented by ring truss deployable mesh antennas has attracted the attention of scholars in the aerospace industry from all over the world. Force density is the most widely used form finding algorithm for mesh antennas. The force density method assumes that the truss nodes of the antenna are rigidly connected, In this paper, an integral form finding algorithm for cable truss antenna is proposed, and the difference between the two algorithms is compared.
An operator splitting method for solving dimensionless radiation hydrodynamics equations
Authors: Yan Kai , Fu Meiyan , Han Feng , Yao Chengbao , Lei Yu
Published: September 2021

By non-dimensionalizing the radiation hydrodynamics equations in the form of Boltzmann-Euler coupling, the two moments approximate model written with non-dimensional variables is proposed and the non-dimensionalization leads to two parameters. An operator splitting method is developed to solve the dimensionless radiation hydrodynamics equations. The advantage of this method is that instead of solving nonlinear equations, it solves a set of ordinary differential equations, and these ordinary differential equations are decoupled. Lastly, the paper describes the Su-Olson problem which has a semi-analytic solution. The analysis shows that the solutions of numerical simulation agree well with the semi-analytic solutions in equilibrium diffusion limit.
Calculus of a kind of improper integral
Authors: Pan Yuefeng , Shi Menghan , Shen Tianle
Published: September 2021

The calculation of improper integral is of great importance. In this paper, we consider a kind of real improper integral using the method of complex analysis and prove the equation

∫
0
∞

x
α

(
1
+

x
β

)
x

d
x

=

π

β

sin

α
π

β

. Firstly we give the condition for the convergence of the improper integral

∫
0
∞

x
α

(
1
+

x
β

)
x

d
x

when

0
<
α
<
β

, so we can see the integrand as a complex function. This function is defined on a simply connected set not containing zero to ensure that the function is holomorphic. We use three methods to prove the equation. In the first method, we choose a certain closed path as the boundary of the simply connected set, compute the integral along the path by the Residue Formula according to Cauchy’s Theorem, and obtain the value of the real improper integral. In the second method, we use Mellin transform, while the idea is similar to that of the Residue Formula. In the third method, we find that the path we choose becomes simpler by a variable substitution. The function that is integrated along the new path does not have the problem of multivaluedness, so we do not have to define it on a simply connect set. Moreover, using the method of complex analysis, we prove that the equation holds when α, β are complex numbers, and the condition is about the real parts of α and β, i.e.,

0
<
ℜ
α
<
ℜ
β

. The real improper integral is just a particular case where α, β are real numbers. We compute the value of such kind of complex improper integral by some calculation and simplification, which is exactly

π

β

sin

α
π

β

. We find the relationship between this integral and gamma function. The equation can prove a property of gamma function. We prove that the equation holds when α, β are complex numbers, and the condition becomes

0
<
ℜ
α
<
ℜ
β

. We hope that this can be used in the research of more properties of the gamma function. The proof of the equation reminds us of a way of calculating such kinds of real improper integrals.
Finite difference method based on polynomial interpolation for solving Helmholtz equation
Authors: Zhang Zihan , Fang Silong
Published: September 2021

The generalized finite difference formula plays an important role in the meshless method for solving differential equations. The main purpose of this paper is to find the numerical solution of Helmholtz equation, an elliptic partial differential equation describing electromagnetic waves in physics, by using the generalized finite difference formula. Firstly, this paper introduces a simple and practical nodal distribution, which not only guarantees the uniqueness of multivariate polynomial interpolation, but also makes the matrix triangular, so that the constructed basic polynomials can be transformed into Lagrange basis polynomials. Secondly, the generalized finite difference formula is created by polynomial interpolation. Finally, a numerical example of Helmholtz equation under general boundary conditions is given.