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Scanning the energy dissipation process of energetic materials based on excited state relaxation and vibration–vibration coupling

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Chinese Physics B 2018年第10期27卷 341-345页

作者： Wen-Yan Wang Ning Sui Li-Quan Zhang Ying-hui Wang Lin Wang Quan Wang Jiao Wang zhi-hui kang Yan-Qiang Yang Qiang Zhou Han-Zhuang Zhang Femtosecond Laser Laboratory Key Laboratory of Physics and Technology for Advanced Batteries（Ministry of Education）College of PhysicsJilin UniversityChangchun 130012China State Key Laboratory of Superhard Materials College of PhysicsJilin UniversityChangchun 130012China National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900China

The energy dissipation mechanism of energetic materials（EMs） is very important for keeping safety. We choose nitrobenzene as a model of EM and employ transient absorption（TA） spectroscopy and time-resolved coherent anti-stokes Raman scattering（CARS） to clarify its energy dissipation mechanism. The TA data confirms that the excited nitrobenzene spends about 16 ps finishing the twist intramolecular charge transfer from benzene to nitro group, and dissipates its energy through the rapid vibration relaxation in the initial excited state. And then the dynamics of vibrational modes（VMs） in the ground state of nitrobenzene, which are located at 682 cm^-1（v1）, 854 cm^-1（v2）, 1006 cm^-1（v3）, and 1023 cm^-1（v4）,is scanned by CARS. It exhibits that the excess energy of nitrobenzene on the ground state would further dissipate through intramolecular vibrational redistribution based on the vibrational cooling of vi and v2 modes, v1 and v4 modes, and v3 and v4 modes. Moreover, the vibration-vibration coupling depends not only on the energy levels of VMs, but also on the spatial position of chemical bonds relative to the VM.

关键词： energy dissipation charge transfer transient absorption coherent anti-stokes Raman scattering(CARS)

Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

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Chinese Journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui ZHAO Yueshuai SONG hui kang Min WAN School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its *** achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution *** evolution analysis was conducted based on Electron Back Scatter Diffraction(EBSD),Scanning Electron Microscopy(SEM),X-Ray Diffraction(XRD),High-Resolution Transmission Electron Microscopy(HRTEM),and Focused Ion Beam(FIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension *** findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORDS Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

Experimental investigation on fluid-induced slip behavior of fault filled with fault gouge

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3661-3672页

作者： Yongshui kang zhi Geng Bin Liu Youqi Huang State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Fault zones are usually filled with fault gouge and accompanied by fault *** coupled effect of fault gouge and water significantly impacts the slip behavior of the fault,which may weaken the fault structure and further induce rupture propagation and *** this study,we carried out a laboratory experiment to investigate the fluid-induced slip behavior of fault filled with *** friction evolution characteristic associated with fluid pressure and effective stress was investigated during the slip *** addition,the role transformation process of the gouge on the slip behavior of fault was *** experimental result indicates that the friction on the filled fault surface is significantly affected by fault *** rupture of the gouge promotes fault slip and the fluid pressure plays a vital role in the initiation of fault *** fault gouge enhances the shearing strength of the fault and acts as a barrier before the initial slip under fluid ***,the fault gouge would accelerate the fault slip and transform into lubricant after the initial slip.

关键词： Fault gouge Fluid Slip behavior Friction Shear strength

Degradation and biocompatibility of one-step electrodeposited magnesium thioctic acid/magnesium hydroxide hybrid coatings on ZE21B alloys for cardiovascular stents

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Journal of Magnesium and Alloys 2024年第1期12卷 120-138页

作者： Zhao-Qi Zhang Bing-zhi Li Pei-Duo Tong Shao-kang Guan Li Wang Zheng-hui Qiu Cun-Guo Lin Rong-Chang Zeng School of Material Science and Engineering&Henan Key Laboratory of Advanced Magnesium Alloy&Key Laboratory of Materials Processing and Mold Technology(Ministry of Education) Zhengzhou University100 Science RoadZhengzhou 450001China State Key Laboratory for Marine Corrosion and Protection Luoyang Ship Material Research InstituteQingdao 266101China Corrosion Laboratory for Light Metals College of Material Science and EngineeringShandong University of Science and TechnologyQingdao 266590China

Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based ***,the steps for preparing composite coatings are usually complicated and ***,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step *** electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform *** the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch *** test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg *** experiment and cell culture trial detect that the composite coating is of fine ***,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and *** coating shows a great potential application for cardiovascular stents.

关键词： Magnesium alloy Corrosion resistance Hybrid coating Endothelialization Biocompatibility

Microstructure and texture evolution of Cu–Cr–Co–Ti alloys during the two-stage cryorolling

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Rare Metals 2024年第9期43卷 4535-4547页

作者： Jia-Jun Zhang Long-Jian Li zhi-Feng Liu Zong-Ning Chen En-Yu Guo hui-Jun kang Ren-Geng Li Tong-Min Wang Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) School of Materials Science and EngineeringDalian University of Technology Center of Hyper-Gravity Experimental and Interdisciplinary Research Zhejiang University Ningbo Institute of Dalian University of Technology！Ningbo315000 China Key Laboratory for Light-Weight Materials Nanjing Tech University

This study entailed an investigation of the mechanical properties, microstructural and texture orientation evolutions of CuDCrDCoDTi alloys prepared via twostage cryorolling and intermediate aging treatment. To this end, X-ray diffraction and electron backscatter diffraction were employed. The results indicate that the two-stage cryorolling and intermediate aging treatments led to the development of profuse twin bundles and significantly enhanced the mechanical properties. The initial cryorolling led to coplanar slip and developed a strong Y({111} ) orientation, accelerating the formation of Goss({011} ) orientation and a Brass-type *** intermediate aging treatment relieved the restriction on dislocation slip and reoriented the grains toward the Copper({112} ) and Z({111} ) *** Z orientation, with a relatively high volume fraction,dominated the macrotexture. Secondary cryorolling intensified twinning and shear banding, transforming the Copper-type shear bands into Brass-type shear bands with rhomboidal prism morphology. The areas inside the Brasstype shear bands exhibited a Y orientation, and the areas outside the shear bands exhibited a stable Brass-type texture. The evident decrease in the weighted Schmid factors demonstrated that the two-stage cryorolling and intermediate aging treatment can modify the texture evolution and aid the design of high-performance Cu alloys.

关键词： Copper alloys Electron backscatter diffraction Macrotexture evolution Schmid factor Two-stage cryorolling

On the Specificity of Nanozymes: A Perspective

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Chinese Journal of Chemistry 2024年第13期42卷 1515-1522页

作者： Gen Wei Shuje Liu Yung-kang Peng hui Wei Department of Biomedical Engineering College of Engineering and Applied SciencesNanjing National Laboratory of MicrostructuresJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjingJiangsu 21023China Department of Chemistry.City University of Hong Kong Hong Kong 999077Hong Kong SARChina State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical EngineeringChemistry and Biomedicine Innovation Center(ChemBIC)Nanjing UniversityNanjingJiangsu 210023China NMPA Key Laboratory for Biomedical Optics HangzhouZhejiang 310018China

We have compiled eight promising strategies for enhancing the specificity and selectivity of nanozymes,as depicted in the comprehensive summary *** exhibit intricate and sophisticated structures,including substrate channels and active sites,which can inform the design of *** of these structural features and the application of facet engineering/doping techniques can significantly enhance the catalytic specificity of ***,the use of Molecularly Imprinted Polymers(MiPs)to coat nanozymes represents an effective approach to impart substrate ***,several straightforward stopgap strategies have been devised to improve nanozyme specificity for analytical applications,such as the integration of biorecognition elements and nanozyme sensor arrays through surface modification.

关键词： Nanozymes Enzymes Catalytic activity Specificity Perspective

Toward a Direct Measurement of the Cosmic Acceleration:The Pilot Observation of HI 21 cm Absorption Line at FAST

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Research in Astronomy and Astrophysics 2024年第7期24卷 47-55页

作者： Jiangang kang Chang-zhi Lu Tong-Jie Zhang Ming Zhu Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China School of Physics and Astronomy Beijing Normal UniversityBeijing 100875China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

This study presents results on detecting neutral atomic hydrogen(H I)21 cm absorption in the spectrum of PKS PKS1413+13 at redshift z=*** observation was conducted by FAST,with a spectral resolution of10 Hz,using 10 minutes of observing *** global spectral profile is examined by modeling the absorption line using a single Gaussian function with a resolution of 10 kHz within a 2 MHz *** goal is to determine the rate of the latest cosmic acceleration by directly measuring the redshift evolution of the H I 21 cm absorption line with Hubble flow toward a common background quasar over a decade or longer time *** will serve as a detectable signal generated by the accelerated expansion of the Universe at redshift z<1,referred to as redshift drift z(5)or the SL *** measured H I gas column density in this DLA system is approximately equivalent to the initial observation value,considering uncertainties of the spin temperature of a spiral host *** high signal-to-noise ratio of 57,obtained at a 10 kHz resolution,strongly supports the feasibility of using the H I 21 cm absorption line in DLA systems to accurately measure the redshift drift rate at a precision level of around 10~(-10)per decade.

关键词： (cosmology)cosmological parameters-cosmology observations-cosmology theory-(cosmology)dark energy-radio lines ISM-radio lines galaxies-ISM clouds

Preparation of three-dimensional nanoporous copper foil with high specific surface area

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Rare Metals 2024年第7期43卷 3430-3437页

作者： Ning Song Li-Juan Wang Jun-Feng Wang Juan Liao Jian Huang Peng-kang Du Yun-zhi Tang Yu-hui Tan Xiao-Wei Fan Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry School of Chemistry and Chemical EngineeringJiangxi University of Science and TechnologyGanzhou 341000China

The porous copper foil material has the advantages of ultralight and ultra-thin,and can prevent dangers such as thermal runaway and battery fire,which could be regarded as a prospective material for lithium battery **... 详细信息

关键词： copper porous dimensional

MnS–MnO heterogeneous nanocube@N,S-doped carbon as a highly efficient bifunctional water splitting electrocatalyst

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Rare Metals 2024年第5期43卷 1977-1988页

作者： Xue-Qian Wang Xiang-Ying Ma Wang-zhi Wu hui-Bing He Nan-Nan Wang Ren-Ji Zheng Shao-Jian Ma Yan-Qiu Zhu Pei-kang Shen Jin-Liang Zhu School of Resources Environment and MaterialsState Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite StructuresCollege of Chemistry and Chemical EngineeringGuangxi UniversityNanning 530004China School of Chemistry and Chemical Engineering Guangxi MinzuUniversity Nanning 530006 China School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

A stable,efficient,and economical bifunctional electrolytic catalyst would be incredibly beneficial for the development of hydrogen production by electrocatalytic water *** this study,we synthesized a novel MnS–MnO heterogeneous nanocube@N,S-doped carbon(MnS–MnO@NSC).MnS–MnO nanocubes possess rich heterogeneous interfaces and plentiful catalytic active sites to promote electrochemical reactions,while the N,S-doped carbon shell possesses excellent conductivity and catalytic properties and protects the ***–MnO@NSC exhibited excellent electrochemical properties as an effective bifunctional electrocatalyst for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in KOH *** the HER,the overpotential was as low as 124 mV at a current density of 10 mA·cm^(-2)while in the OER,it was only 340 mV at 100 mA·cm^(-2)under the same *** addition,a MnS–MnO@NSC||MnS–MnO@NSC electrolyzer exhibited almost comparable activity and higher steadiness than those exhibited by the state-of-the-art Pt/C||RuO_(2)/C system for full water splitting in KOH solution.

关键词： Manganese sulfide Manganese oxide Doped carbon Heterogeneous nanocube Water splitting