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Experimental study on WFeNiMo high-entropy alloy projectile penetrating semi-infinite steel target

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Defence Technology（防务技术） 2022年第8期18卷 1470-1482页

作者： Hai-hua Chen Xian-feng Zhang Lan-Hong Dai Chuang Liu Wei Xiong Meng-ting Tan School of Mechanical Engineering Nanjing University of Science&TechnologyNanjingXiaolingwei 200Jiangsu210094China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Science University of Chinese Academy of SciencesBeijing101408China

The appearance of high-entropy alloys (HEAs) makes it possible for a material to possess both high strength and high ductility. It is with great potential to apply HEAs under extreme conditions such as in the penetration process. In this paper, experiments of WFeNiMo HEA and tungsten heavy alloy (WHA) projectiles penetrating medium-carbon steel were conducted by using the ballistic gun and two-stage light-gas gun that can accelerate projectiles to impact velocities ranging from 1162 m/s to 2130 m/s. Depth of penetration (DOP) at elevated impact velocities of HEA and WHA projectiles were obtained firstly. Combined with the macroscopic and microscopic analysis of the residual projectiles, the transition of the penetration mode of the WFeNiMo HEA projectile was identified systemically. The experimental results indicated that the penetration mode of the HEA projectile changes from self-sharpening to mushrooming with the increase of impact velocity, while for the WHA projectile, the penetration mode is always mushrooming. The microstructure of the residual HEA projectiles showed that the phases tangle with each other and the morphology of the microstructure of the phases differs in the two penetration modes. Besides, the evolution of shear bands and fractures varies in the two modes. The evolution of the microstructure of HEAs causes the sharp-pointed nose to disappear and the HEA projectile ultimately becomes blunt as the impact velocity increases.

关键词： WFeNiMo high-entropy alloys Tungsten heavy alloys Penetration mode Self-sharpening penetration Mushrooming deformation

Theoretical analysis for self-sharpening penetration of tungsten high-entropy alloy into steel target with elevated impact velocities

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Acta Mechanica Sinica 2021年第6期37卷 970-982,I0002页

作者： Haihua Chen Xianfeng Zhang Chuang Liu Wei Xiong Mengting Tan Lan-Hong Dai School of Mechanical Engineering Nanjing University of Science&TechnologyXiaolingwei 200Nanjing210094China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Science University of Chinese Academy of SciencesBeijing101408China

The“self-sharpening”effect has been observed experimentally in the penetration of tungsten high-entropy alloy(WHEA)into steel targets in previous study.From the microscopic observation of the residual WHEA long-rod projectile(LRP),the multiphase structure at micro-scale of WHEA is the key effects on self-sharpening penetration process.In order to describe the distinctive penetration behavior,the interaction between micro phases is introduced to modify the hydrodynamic penetration model.The yield strengths of WHEA phases are determined based on the solid solution strengthening methods.Combined with the elbow-streamline model,the self-sharpening mechanism is revealed in view of the multi-phase flow dynamics and the flow field in the deformation area of the LRP nose is characterized to depict the shear layer evolution and the shape of the LRP’s nose as well as the determination of the penetration channel.The self-sharpening coefficient considering the reduction of nose radius is proposed and introduced into the penetration model to calculate the depth of penetration and the penetration channel.Results show that the multi-phase interaction at the microscopic level contributes to the inhomogeneous distribution of the WHEA phases.The shear layer evolution separates part of the LRP material from the nose and makes the nose radius decrease more quickly.It is also the reason that WHEA LRPs have a pointed nose compared with the mushroom nose of WHA heavy alloy(WHA)LRPs.The calculated results agree well with the corresponding experimental data of WHA and WHEA LRPs penetrating into semi-infinite medium carbon steel targets with elevated impact velocities.

关键词： Impact dynamics Long-rod projectile Tungsten high-entropy alloy(WHEA) Self-sharpening penetration Solid solution strengthening

Eutectic high entropy alloy syntactic foam

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Journal of Materials Science & Technology 2023年第18期149卷 177-189页

作者： Jin Meng Yu Qiao Tian-Wei Liu Yuan-Yuan Tan Fu-Hua Cao Yan Chen Hai-Ying Wang Lan-Hong Dai State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of Sciences(CAS)Beijing 100190China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Engineering Science University of Chinese Academy of SciencesBeijing 101408China CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei 230027China

High-strength metallic foams have a wide range of applications in engineering as lightweight structural and energy-absorbing materials.However,it is challenging to obtain metallic foam with both good energy absorption performance and high strength.Here,we developed a novel metal matrix syntactic foam fabri-cated with AlCoCrFeNi_(2.1) eutectic high entropy alloy and alumina cenospheres that exhibits a remarkable combination of high strength and energy absorption performance under both quasi-static and dynamic compression.The porous structure of syntactic foam fully exploits the properties of the AlCoCrFeNi_(2.1) alloy matrix with a unique FCC/B2 dual-phase eutectic microstructure and thus yields exceptional per-formance.We discovered that this dual-phase microstructure not only provides high strength but also allows the pores to collapse in a progressive and diffusive way,which enables the formation of a high and smooth energy absorption platform.It is found that the heterogeneity between the two phases in the matrix can provide back stress strengthening,and it also induces multiple micro shear bands and microcracks as additional energy dissipation modes as the deformation proceeds.This unique mechanism ensures the strength of microstructures and makes them fracture promptly,which causes the balance of strengthening and softening on the macro scale.This work opens the avenue for developing advanced high-strength lightweight structural and energy-absorbing materials.

关键词： Eutectic high entropy alloy Foams Metal matrix composites(MMCs) Energy absorption

Epidural Block Treatment on Postherpetic Neuralgia and Comorbid Spine Metastasis of Malignant Tumor:Two Cases of Report

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International Journal of Dermatology and Venereology 2021年第1期4卷 53-55页

作者： Jin-Yan dai An-lan hong Yan Wang Hospital for Skin Diseases(Institute of Dermatology) Chinese Academy of Medical Sciences and Peking Union Medical CollegeNanjingJiangsu 210042China

Introduction:Postherpetic neuralgia(PHN)is a painful condition that occurs after herpes zoster skin lesions have subsided and that lasts for more than 1 month.PHN is usually difficult to treat.Case presentation:Patient 1 was a 54-year-old woman who had PHN for 35 days.Patient 2 was a 74-year-old woman who had PHN for 65 days.Both patients were treated with an epidural block and found to have spinal metastasis from a malignant tumor.Discussion:The routinely used dermatological medications for the treatment of herpes zoster and PHN have slow and unsatisfactory analgesic effects.Epidural block treatment provides a new approach for patients who cannot tolerate or do not respond to these commonly used drugs.Physicians should pay special attention to patients who have a history of a malignant tumor or are suspected to have spinal disease.Computed tomography or magnetic resonance imaging of the spine is recommended for such patients,and epidural block treatment should be performed after a spinal tumor or other lesions have been excluded.Conclusion:Epidural block treatment provides a new approach for patients of herpes zoster or PHN,but the treatment should be performed after a spinal tumor or other spinal lesions have been excluded.

关键词： epidural block treatment postherpetic neuralgia spinal tumor

Polyphenols from Securidaca inappendiculata alleviated acute lung injury in rats by inhibiting oxidative stress sensitive pathways

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Chinese Herbal Medicines 2021年第3期13卷 381-388页

作者： Cong-lan Ji Sheng dai hong Liu Ji-yang Dong Chun-sheng Liu Jian Zuo Department of Pharmacy Anhui College of Traditional Chinese MedicineWuhu 241000China Department of Electronic Science Xiamen UniversityXiamen 361005China Yijishan Hospital Wannan Medical CollegeWuhu 241000China Key Laboratory of Non-coding RNA Transformation Research of Anhui Higher Education Institution(Wannan Medical College) Wuhu 241000China Provincial Engineering Laboratory for Screening and Re-evaluation of Active Compounds of Herbal Medicines in Southern Anhui(Wannan Medical College) Wuhu 241000China

Objective:Securidaca inappendiculata is a medicinal plant frequently used in the treatment of inflammatory diseases in south China.In this study,we aimed to explore its bioactive constituent which contributes to the anti-inflammatory activity.Methods:Polyphenol-enriched and polyphenol-deprived fractions(PRF and PDF,respectively)were separated from the ethanolic extract by HPD300 macroporous resin-based method,and their antiinflammatory activities were investigated on a lipopolysaccharide(LPS)-induced acute lung injury(ALI)model in rats.The possible mechanism of action in alleviating acute inflammation was studied using RAW264.7 cells.Results:Both Folin-Ciocalteu and^(1)H nuclear magnetic resonance(NMR)analyses showed that polyphenolic content in PRF was approximately 10 times higher than that of PDF,and this observation reflected in their antioxidative capacities.PRF but not PDF significantly decreased the level of malondialdehyde,suppressed the expression of nicotinamide phosphoribosyltransferase(NAMPT)protein,and improved the severity of ALI in rats.PRF at 10μg/mL effectively downregulated the expression of proteins NAMPT,HMGB1,TLR4,and p-p65,and scavenged the intracellular reactive oxygen species(ROS)in LPS-primed RAW264.7 cells.N-acetyl-L-cysteine exhibited similar inhibitory effects on ROS production and NAMPT-mediated TLR4/NF-κB activation in vitro,whereas nicotinamide mononucleotide antagonized all the changes induced by PRF during cotreatments.Conclusion:As an antioxidant,PRF exhibited potent anti-inflammatory activity under both in vivo and in vitro conditions by downregulating NAMPT and TLR4/NF-κB.Accordingly,polyphenols were identified as important bioactive constituents in S.inappendiculata targeting oxidative stress-sensitive proinflammatory pathways.

关键词： antioxidant polyphenols reactive oxygen species(ROS) Securidaca inappendiculata Hassk TLR4/NF-κB

An In-Memory-Computing Design of Multiplier Based on Multilevel-Cell of Resistance Switching Random Access Memory

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Chinese Journal of Electronics 2018年第6期27卷 1151-1157页

作者： dai lan GUO hong LIN Qipeng XIA Yongxin ZHANG Xiaobo ZHANG Feng FAN Dongyu North China University of Technology Institute of Microelectronics of Chinese Academy of Sciences

Due to the Von Neumann bottleneck,in-memory-computing, as a new architecture, has drawn considerable attention and is becoming an candidate of next generation electronics system. It presents an inmemory-computing approach for multiplier design based on Multilevel-cell(MLC) of Resistive random access memories(RRAMs). The paper proposes a Look-up-table(LUT) operations to optimize the speed, area and power of the multiplier circuits. The proposed MLC function of RRAM revealed that RRAM could have a multilevel stable resistance by adjusting the operating voltage. The simulation results show that, taking a 16-bits multiplier as an example, the circuits of this paper has a calculation speed that is increased by 35.7 percent and an area that is decreased by 14 percent under the similar power consumption conditions when compared with other traditional 16-bits multiplier.

关键词： Resistive random access memory(RRAM) Multilevel-cell(MLC) storage Look-up-table(LUT) In-momery-computing

Lattice distortion and magnetic property of high entropy alloys at low temperatures

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Journal of Materials Science & Technology 2022年第9期104卷 236-243页

作者： Yuan-Yuan Tan Zhong-Jun Chen Ming-Yao Su Gan Ding Min-Qiang Jiang Zhou-Can Xie Yu Gong Tao Wu Zhong-Hua Wu Hai-Ying Wang Lan-Hong Dai State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Institute of High Energy Physics Chinese Academy of Sciences&GraduateUniversity of Chinese Academy of SciencesBeijing 100049China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Zhejiang Institute of Mechanical&Electrical Engineering Hangzhou 310053China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

Deformation mechanisms and magnetic properties of medium and high entropy alloys(MEA/HEAs)closely relate to lattice distortion and are strongly temperature-dependent,in particular,at low temperature ranges.However,little attention has been paid to the evolution of lattice distortion with temperature decreasing and its effects on deformation behavior and magnetic state transition.In this work,we carry out in situ synchrotron radiation based X-ray powder diffraction(SR-XRD)experiments from 293 to 123 K aiming for determining lattice distortion evolutions of Cr Co Ni MEA,Cr Fe Co Ni and Cr Mn Fe Co Ni HEAs.Magnetic measurements at corresponding low temperatures and cryogenic ranges are further conducted.The in situ SR-XRD results demonstrate a general reduction of lattice distortion magnitude with temperature decreasing,which shows a similar tendency with that of reported stacking fault energy(SFE)values.It is thus suggested that lattice distortion reduction possibly makes a critical contribution to deformation mechanism transition.The magnetic measurement results show a clear ferromagnetic transition of Cr Fe Co Ni HEA when temperature is below 173 K.While,no obvious magnetic state transition is observed for Cr Co Ni MEA and Cr Mn Fe Co Ni HEA.The present findings on lattice distortion evolutions will pave the way for designing targeted HEAs with particular properties.

关键词： High entropy alloy Lattice distortion Magnetic property Low temperature In situ SR-XRD

Influence of Hydrogen Bonding on the Temperature-Accelerated Hydrolysis of Silicone Based Polyetherurethane

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Chinese Journal of Polymer Science 2023年第8期41卷 1230-1237,I0007页

作者： He-Cheng Wu Shu-Ren Shao Shuo-hong Dong Ao Wang Zhen Li Xiang-Long Han Feng Luo Jie-Hua Li dai-Guo Zhao Wan-Ling lan hong Tan College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringMed-X Center for MaterialsSichuan UniversityChengdu 610065China State Key Laboratory of Oral Diseases National Clinical Research Center for Oral DiseasesWest China Hospital of StomatologySichuan UniversityChengdu 610041China Sichuan Institute for Food and Drug Control Chengdu 611731China

Temperature-accelerated in vitro degradation was established to estimate the longevity of polyurethane applied for long-term implantation.However,the prediction did not correlate well with the data from clinical explants and the rationality of accelerated in vitro test is still in a controversial due to the deviation.To improve the accuracy of the in vitro prediction,the influence of hydrogen bonding(HB)on the accelerated hydrolysis of silicone based polyetherurethans(SPEUs)extended with three side chains.Combining the temperature-controlled FTIR and the physical properties after temperature-accelerated in vitro degradation,it was demonstrated that side chain could increase the degree of hydrogen bond dissociation at higher temperature,resulting in the decrease of the calculated activation energy(E_(a))of hydrolysis.At low temperatures,changes in surface morphology and molar mass of PEUs are minimal and HB are less easily dissociated,which had barely impact on the hydrolysis resistance.It was proposed that the E_(a) will not be impacted and that the accuracy of prediction will be increased if the acceleration temperature is lower than 70℃ and HB change is less than 15%.

关键词： Polyether urethane Polydimethylsiloxane Activation energy Hydrogen bonding Hydrolysis resistance

The emerging role of exosomes in the development of testicular

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Asian Journal of Andrology 2023年第5期25卷 547-555页

作者： Chun-Yang Li Song-Po Liu Xiao-Fang dai Dong-Feng lan Tao Song Xian-Yao Wang Qing-hong Kong Jun Tan Ji-Dong Zhang Department of Immunology Zunyi Medical UniversityZunyi 563000China Special Key Laboratory of Gene Detection and Therapy of Guizhou Province Zunyi Medical UniversityZunyi 563000China Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine Zunyi Medical UniversityZunyi 563000China Guizhou Provincial College-Based Key Lab for Tumor Prevention and Treatment with Distinctive Medicines Zunyi Medical UniversityZunyi 563000China Department of Histology and Embryology Zunyi Medical UniversityZunyi 563000China

The mechanisms of testicular development in mammals are complex.Testis is an organ that produces sperm and secretes androgens.It is rich in exosomes and cytokines that mediate signal transduction between tubule germ cells and distal cells,promoting testicular development and spermatogenesis.Exosomes are nanoscale extracellular vesicles that transmit information between cells.By transmitting information,exosomes play an important role in male infertility diseases such as azoospermia,varicocele,and testicular torsion.However,due to the wide range of sources of exosomes,extraction methods are numerous and complex.Therefore,there are many difficulties in studying the mechanisms of exosomal effects on normal development and male infertility.Therefore,in this review,first,we introduce the formation of exosomes and methods for culturing testis and sperm.Then,we introduce the effects of exosomes on different stages of testicular development.Finally,we summarize the prospects and shortcomings of exosomes when used in clinical applications.We lay the theoretical foundation for the mechanism of the influence of exosomes on normal development and male infertility.

关键词： exosomes miRNA Sertoli cells sperm testis