bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation on the Damage Mode and Anti-penetration Performance of B4C/UHMWPE Composite Targets for Different Incident Velocities and Angles
Authors: Wang Hongfei , Wang Jinxiang , Tang Kui , Chen Xingwang , Li Yuanbo 
Published: April 2021

Abstract
To found out the effects of incident velocity and incident angle on the damage mode and anti-penetration performance of ceramic composite targets, and provide a certain basis for optimizing the structural design of ceramic composite armor. The penetration of 7.62 mm bullet into oblique boron carbide (B4C)/UHMWPE composite target was investigated by ballistic testing and numerical simulation. The effects of incident velocity and incident angle on the fragmentation degree of bullet and ceramic panel were analyzed, also the damage mode of bullet penetrating ceramic composite target was developed preliminarily to estimate the anti-penetration performance of ceramic composite targets. Based on the testing and simulation results, it was found that the fragmentation degree of bullet and ceramic panel increases gradually with the increase of incident velocity and incident angle, but the fragmentation degree of bullet and ceramic panel decreases obviously when the incident velocity exceeds the ballistic limit; the damage mode of UHMWPE laminate is mainly tensile failure when the bullet’s incident velocity is lower than the ballistic limit, and the increase of incident velocity or incident angle makes UHMWPE laminate more prone to shear failure and delamination failure. With the increase of incident angle, the ballistic limit of B4C/UHMWPE composite target increases significantly, the deflection angle of bullet increases similarly, and the optimal thickness ratio of ceramic panel and backplate tends to decrease with the increase of incident angle.
Analysis on Injury for Light Armored Vehicle Occupant by the After-effect Fragments of Rifle Projectile
Authors: Li Jinming , Yan Wenmin , Wang Shu , Lu Dabin , Mai Ruimin 
Published: April 2021

Abstract
Armor-piercing projectile is one of the main threats faced by light armored vehicles. The after-effect fragments formed by projectile penetrating armor will cause injuries to the occupants. It is an important reference for evaluating the impact of the armor-piercing projectile on light armored targets. The characteristics of after-effect fragments have a great influence on the lethal efficiency of internal occupants, especially those wearing bulletproof vests. In order to study the injury effect of the after-effect fragments on occupants, the 12.7 mm multifunctional bullet was tested to 10 mm armored steel to obtain the mass distribution of after-effect fragments at different speeds, and then a finite element model of the effect of after-effect fragments on the human thorax FEM with soft body armor was established. Through numerical simulation, the impact of different after-effect fragments of bullets was obtained. The stress changes, pressure changes and etc. of human model after the impact of different after-effect fragments were obtained that provides a basis for further evaluation of the injury effect of fragments on occupants in light armored vehicles.
Experimental Study on Ballistic Performance of Lateral Constraint Ceramic Structures
Authors: Wu Hailing , Zhang Shengjun , Cui Xinzhong , Li Daji , Zhong Tao , Miao Cheng , Wu Xin 
Published: April 2021

Abstract
Thermal Bush restraint technology was used to control the thickness of the restraint layer by applying the restraint layer on the ceramic lateral. Different thickness of circular SiC ceramic was confined lateral with steel Bush of 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm and 3.5 mm thickness according to the characteristics of thermal expansion and cold contraction of steel bushing, and lateral restraint of which was calculated. Ballistic resistance of lateral constraint ceramic structure was studied by firing 105 mm armor-piercing simulated projectile with 25 mm ballistic gun. And it turns out: the greater the lateral restraint on the ceramics, the smaller the penetration depth of the projectile into the after-effect target the higher the ballistic resistance of the target with increase of thickness of lateral restraint layer. In the design of armor structure, thickness of lateral restraint layer should be reduced as much as possible considering requirement of light weight under the condition of achieving the required ballistic performance to improve the overall ballistic performance of lateral restraint ceramic armor structure.
Simulation Study on the Performance of Kevlar Fibre Reinforced Composites Under the Penetration of Fragment
Authors: Li Shuhu , Wang Ronghui , Zhang Dashun , Du Juan , Xu Jingli , Zhang Haiyun , Liu Fangbiao 
Published: April 2021

Abstract
Aiming at the problem of Kevlar fibre reinforced composite target anti penetration of wedge-shaped fragment, the finite element models of Kevlar fibre reinforced composite targets with different thickness and the fragments are established. The simulation calculation of Kevlar fibre reinforced composite target against penetration of different velocity fragments is carried out. The anti-ballistic V50 of Kevlar fibre reinforced composite target with different thickness is obtained, and the damage failure mode of the Kevlar fibre reinforced composite target in the process of anti fragment penetration is analyzed, and the simulation results are verified by experiments. This simulation provides scientific basis and data support for the optimization design of composite structure armor and armor lining.
Research Progress of Numerical Simulation Method Based on the Protection Performance of STF-Kevlar Fabric Liquid Armor Composites
Authors: Li Shuhu , Xu Jingli , Zhang Jianqin , Wu Lianqi , Zhang Haiyun , Wei Huazhen , Wang Danyong , Chen Yiwei , Gao Yingying 
Published: April 2021

Abstract
In this paper, the numerical simulation method for the protection performance of liquid armor based on STF can be roughly summarized into two ways, containing the shell element simulation method based on the inter-yarns friction coefficient and the coupled Euler-Lagrangian simulation method. The shell element simulation method of inter-yarns friction coefficient has a single consideration for STF performance, but it has high calculation efficiency and low calculation cost. The coupled Euler-Lagrangian simulation method fully considers the shear thickening characteristics of STF, and comprehensively considers the characteristics of STF. The simulated performance gets closer to the actual situation, and it can also reveal the effect of STF in improving the protection performance.
Research on Penetration Performance of Tandem Damage Elements to Oblique Reactive Armor
Authors: Chang Bianhong , Yin Jianping , Zhang Yu , Shi Zhixing 
Published: April 2021

Abstract
In order to study the penetration performance of the tandem warhead against the oblique reactive armor target, ANSYS/LS-DYNA finite element simulation software was used to simulate the penetration process of the tandem warhead against the oblique reactive armor target when the front liner of the tandem warhead was made of different materials. The results show that when the front liner material is copper, the formed jet penetrates the reactive armor and will detonate it. The rear jet is greatly affected by the reactive armor, and the final penetration depth is 550 mm; when the front liner material is material is polytetrafluoroethylene (PTFE), the formed low-density jet penetrates the reactive armor and does not detonate it. The rear jet directly penetrates the main target plate along the low-density jet penetration hole, and the final penetration depth is 646 mm, compared with the tandem warhead As far as the front liner uses copper jet, the penetration depth is increased by 17.45%.
Study on Prediction Technique for Fragments of Counterattack Projectiles for Active Protection
Authors: Kang Zhenyu , Lv Juan , Yuan Shuqiang , Li Yazhe , Du Juan 
Published: April 2021

Abstract
This paper aims to predict the distribution of mass and number of natural fragments based on the Payman method and using the fragmentation similarity relation and the correction relation of geometric factors that influence fragmentation. The results showed that the prediction accuracy of the fragment mass and number distribution was up to over 90%. The shape, explosive, material and heat treatment process of a projectile can be optimized through simulation tests to realize the reasonable matching of the projectile material, explosive and structure, thus shortening the development cycle and providing reliable technical means for improving the power of fragmentation munitions in China.
Effects of Environment Temperature on The Attenuation of Quasi-Spherical EFP Velocity
Authors: Li Yue , Niu Shengjun , Shi Haicheng , Ji Xuesong , Hu Xuecen , Li Mingjian 
Published: April 2021

Abstract
A comparison of multiple quasi-spherical EFP warhead tests conducted during different seasons of the year revealed that EFP velocities in the cold season were low. In this paper, the experimental phenomenon is analyzed theoretically base on the principles of EFP and flight dynamics. Due to the difference of air density caused by the different temperature, the aerodynamic drag of EFP with the same aerodynamic shape and initial velocity is obviously different. Because of the hypervelocity of EFP, The impact velocity of EFP on target is also significantly affected after flying over 100 meters. In the paper, the flight velocities of a quasi-spherical EFP at different temperatures is calculated by MATLAB, which is in good agreement with the experimental results. It is necessary to consider the change of environment temperature in engineering practice of quasi-spherical EFP warhead in order to improve kinetic energy margin.
Experimental Research on Igniting the Aviation Kerosene by W-Zr Reactive Fragment
Authors: Liu Kai , Liu Guitao , Chen Min , Liang Dong , Wang Zhiwei , Ge Wenyan , Li Delin 
Published: April 2021

Abstract
Taking W-Zr reactive fragment as the research object, the influence of fragment density, shape and size parameters on the armor-piercing ignition fuel tank was studied through the simulated target test of 12.7mm ballistic gun launch. Combined with high-speed camera, the armor-piercing ignition behavior of the reactive fragment and ignition mechanism were revealed. The results show that the ignition fuel tank with low and medium density activity fragments has better effect, and the ignition speed of the fragments with high density decreases about 26%. The cube shape fragments have the best ignition performance, followed by cylindrical fragments and spherical fragments. The ignition ability of 7mm and 8mm fragments is equivalent, while the ignition ability of 8mm fragments is slightly stronger. The ability of W-Zr fragment to ignite aviation kerosene is closely related to the content of active components and the degree of breakage when it hits the target plate. Under the action of high-speed impact on the target plate, the fragments ware quickly broken into fragments with a certain flying Angle and high temperature combustion. Under the coupling action of the impact kinetic energy of the fragments and the chemical reaction heat, the critical ignition condition of fuel is reached, and the fuel tank is ignited.
Observation of Debris Clouds Generated by Hypervelocity Impact of Copper Jets with Thin Aluminum Plats
Authors: Jiao W J , Chang L H , Yuan J F , Su J J , Gan Y D , He H , Xiong C Z 
Published: April 2021

Abstract
With high kinetic energy and excellent penetration performance, metal jets have been widely used in the defence industry. When a thin plate is impacted by a metal jet with a velocity higher than 3 km/s, debris clouds will be generated at both sides of the plates. However, compared with the debris clouds generated by hypervelocity impact of projectiles, debris clouds generated by hypervelocity jets is rarely observed. In this paper, the utility of ultrahigh-speed simultaneous framing and streak photography technology is applied in the experiment of copper jets impact thin aluminum plates at hypervelocity. Debris clouds and front edges of shock waves are clearly observed and recognized after using newly developed technology to effectively restrain excessive exposure caused by intensive self-illumination in the experiment. From framing and streak pictures, the process of jets impact targets is comprehensively and completely recorded and the velocities of the jet and the debris cloud are obtained using the methods of data processing developed in present paper.
Photothermal effect of Copper Sulfide Nanoparticles in Skin Defects in mice
Authors: Gao Ying , Deng Feifan , Shan Xiaoqian 
Published: April 2021

Abstract
Photothermal therapy is a non-invasive or minimally invasive, controllable, and has with good antimicrobial efficiency, while the main thing about skin defects is the prevention of bacterial infection as well as rapid repair and healing. Compared with drug therapy, photothermal therapy has the advantages of convenience and no side effects. In this paper, we mainly synthesize a copper sulfide nanoparticle with photothermal effect and wrap it in biocompatible mesoporous silica to make it work to the maximum extent. We It can be concluded from the data obtained from the defect experiments in mice animals that the skin defects in the mice after irradiated with NIR light take took less time to repair and heal than those mice not irradiated with NIR, so it can be shown that Photothermal photothermal treatment plays an important role here.
High Order Semi-Implicit WCNS for 1D Isentropic and Full Euler Equations
Authors: Chen Xun , Zhang Xu , Jiang Yanqun 
Published: April 2021

Abstract
This paper designs a high order semi-implicit weighted compact nonlinear scheme (WCNS) to solve 1D isentropic and full Euler equations. The Euler equations are split into stiff and non-stiff terms that are solved by the implicit and explicit time discretization method, respectively, in order to improve the computational efficiency for low Mach flows. The fifth-order WCNS is applied for the spatial discretization. Several numerical examples are given to demonstrate the performance of the designed method.
Research on Nonlinear Opto-Mechanical System for Improving Detection Performance
Authors: Xing Weichen , Kong Dezhi , Wang Xin 
Published: April 2021

Abstract
In this paper, the use of optical parametric amplifier to effectively improve the detection performance of nonlinear opto-mechanical system is studied theoretically. At the same time, it is found that by adjusting the nonlinear gain of the optical parametric amplifier and the effective detuning between the input light field and the cavity field, the quantum noise of about 14dB in the squeezed quadrature can be reduced, and the sensitivity of weak force detection can be increased by more than 2 times. On the other hand, the phenomenon of reaction noise cancellation caused by nonlinear cavity combined with homodyne measurement is analyzed and the method of quantum non-destructive measurement is realized, which provides technical reference for weak force detection of nonlinear opto-mechanical system.
Current Status and Development Trend Analysis of Neutron Logging in Uranium Mines in China
Authors: Liu Zhifeng , Ding Chenglong , Wang Ruyang , Cao Junwu 
Published: April 2021

Abstract
Neutron logging is a method of measuring uranium fission neutrons by bombarding uranium in ore beds with neutrons emitted by neutron sources or neutron generators. The pulsed neutron logging technology of uranium ore has been popularized and applied in the United States, Russia, Australia and other countries. The key technology is almost monopolized by these countries, but the technology is prohibited in China. In the field of uranium logging, natural gamma logging has always been used in China for uranium quantification, which is characterized by large error, low efficiency, high cost and technical and economic bottlenecks. Due to the fact that the research and application of pulsed neutron log in the field of petroleum exploration and production is relatively mature in China, it is urgent to develop relevant logging instruments and uranium quantitative interpretation methods as independent intellectual property rights. This will lead to a change in the backward appearance of uranium logging. This paper analyzes the research status and development trend of neutron logging in uranium at home and abroad.
Several Ways to Implement Qubits in Physics
Authors: Lu Fan 
Published: April 2021

Abstract
In order to achieve quantum computation, the qubit preparation is crucial, given that the performance relies on various gate operations, which is determined by the quality of qubit. This paper introduces many qubits, including atoms (neutral atoms and ions) and spins (quantum dots, diamond NV centers, and nuclear magnetic resonance) that depend on various systems. Moreover, they are mentioned separately in this paper due to the significance of superconducting qubits. Meanwhile, the advantages and drawbacks of these qubits are compared, e.g. their coherence (long coherence time between neutral atoms and ions), operating temperature, quantum state reading, quantum system ease of handling, and precision of handling. Challenges as well as corresponding resolved methods have been addressed and reviewed. Current gaps and limitations are also discussed.
Design and Application of Optical System Based on Terahertz Time-of-Flight Imaging
Authors: Wang Yujian , Liu Yongli , Wang Bo , Zhu Xinyong 
Published: April 2021

Abstract
Using the penetration and transientness of Terahertz pulses and the photoconductive delayed detection method, the tomographic imaging of the interior of the object based on the time of flight can be realized. By comparing the transmittance of several crystals and polymers in the Terahertz band, Polymethylpentene (TPX) was selected as the material of Terahertz lens, and High Resistivity Float Zone Silicon (HRFZ-Si) as the material of beam splitter; By comparing the focal depth of normal incidence and oblique incidence optics system, the normal incidence optical system was used to realize time-of-flight imaging; Using the idea of optical-mechanical integration, the corresponding optical camera is designed according to the normal incidence optical system, and the peak-to-valley map and thickness map of the Lithium cobaltate coating of aluminum foil were obtained by time-of-flight imaging, and the defects such as complete shedding of the coating and uneven thickness were observed. The results show that the normal incidence optical system can realize Terahertz time-of-flight imaging and is applicable in the industrial nondestructive testing field.
Visualization Analysis of Nano-Flame Retardant Materials Based on Citespace
Authors: Zhang Dingran , Kong Lingqian , Li Yuanhan , Wang Huiya 
Published: April 2021

Abstract
Based on 3083 articles in the research field of nano-flame retardant materials collected from The Web of Science database from January 1, 2000, to December 31, 2019, the author, institution analysis, keyword analysis and journal co-citation analysis were carried out with Citespace software and bibliometrics method, and the relevant visual knowledge atlas was drawn. The results show that the development of nano-flame retardant materials can be roughly divided into three stages: exploration stage (2000-2005), steady development stage (2006-2013), and rapid growth stage (2014-2019). Yuan Hu, a professor at the State Key Laboratory of Fire Science at the University of Science and Technology of China, and his team published the most articles. The Nanocomposite is the most representative research topic. Keywords zirconium phosphate has the highest frequency of occurrence. The periodical DEGRADATION AND STABILITY has been cited the most. Above all, nano flame retardant materials is a young but the heat of the research subject, this paper reveals the authors and institutions of cooperation relations, the Subject of co-occurrence relations, the relationship between journals were cited in the field of knowledge base, hotspot and development trend of the series of research, in order to provide a valuable reference for the development of its.
Investigation and Optimization Research on Online and Offline Blended Learning of Higher Vocational English from the Perspective of CoI Algorithm
Authors: Jin Xu 
Published: April 2021

Abstract
With the development of information technology, online and offline blended learning has become a universal learning form. In order to investigate and optimize the online and offline blended learning of English in higher vocational colleges, this paper introduces the CoI theory to analyze blended learning. First, design the questionnaire based on the three elements of the CoI theory. After analyzing the results of the questionnaire, conduct related experiments. In order to ensure the accuracy of the results, an experimental group and a control group are set up. After three months, most of the students in the experimental group have improved their performance. The experimental results show that blended learning has a certain positive effect on the improvement of vocational students’ English performance. In addition, it is found through research that there are certain differences in the promoting effect of blended learning on English scores under different scores. Therefore, this article puts forward some suggestions for blended learning.
Color Characteristics of Four-Color Samples in the Foggy Environment under Different Lighting Conditions
Authors: Cui Ganggang , Zhou Xiaoli , Qian Yong , Zhang Zheqian , Liu Muqing 
Published: April 2021

Abstract
Traffic signs should provide clear signals for drivers and passengers under various environmental and geographic conditions. In foggy weather, the signal will be disturbed due to light scattering, which will cause obstacles to recognition. This study simulated a foggy environment in the laboratory, used a standard color card as the target, and introduced a colorimeter to record the color coordinates, then calculated the color difference and analyzed the four-color samples’ color properties in different lighting conditions. We found that as the relative visibility increases, the chromatic aberration of the sample will gradually decrease under different lighting conditions and reach zero when the relative visibility is higher than 70%. We found that the green and blue samples have better color coordinate retention capabilities than the fog’s red and yellow. We compared all tested light sources’ performance, and the results showed that 3000K LED and incandescent lamps are better than other light sources. This study will provide a data basis for the study of traffic safety and accident prevention.
An Integrated Silicon Photonic Chip for Continuous-Variable Quantum Random Numbers Generator Based on Vacuum Fluctuation
Authors: Zhu Menglin , Wang Xiangyu , Xu Bingjie , Yu Song , Chen Ziyang , Guo Hong 
Published: April 2021

Abstract
The deployment of quantum random number generator in fiber optics is strongly limited in real world applications due to the size of the components and their cost. Here we present a quantum random number generator based on vacuum fluctuation using an optical homodyne detection in silicon photonic chip achieving minimum entropy/bit of 8.5 for 10 bits sample. The produced random numbers have passed all NIST randomness tests.