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Evolution of microstructure and properties of a novel Ni-based superalloy during stres. relief annealing

International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1876-1889页

作者： Lei Jia Heng Cui Shufeng Yang Shaomin Lü Xingfei Xie Jinglong Qu Collaborative Innovation center of Steel Technology University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China beijing GAONA Materials&Technology Co. Ltd.Beijing 100081China high-Temperature Materials Institute Central Iron and Steel Research InstituteBeijing 100081China

We discussed the decrease in res.dual stres.,precipitation evolution,and mechanical properties of GH4151 alloy in different annealing temperatures.which were studied by the scanning electron microscope(SEM),high-res.lution transmission electron microscopy(HRTEM),and electron backscatter diffraction(EBSD).The findings reveal that annealing processing has a significant impact on diminishing res.dual *** the annealing temperature rose from 950 to 1150℃,the majority of the res.dual stres.es were relieved from 60.1 MPa down to 10.9 ***,the stres. relaxation mechanism transitioned from being mainly controlled by dislocation slip to a combination of dislocation slip and grain boundary ***,the annealing treatment promotes the decomposition of the Laves,accompanied by the precipitation ofμ-(Mo_(6)Co_(7))starting at 950℃ and reaching a maximum value at 1050℃.The tensile strength and plasticity of the annealing alloy at 1150℃ reached the maximum(1394 MPa,56.1%)which was 131%,200%fold than those of the as-cast alloy(1060 MPa,26.6%),but the oxidation process in the alloy was accelerated at 1150℃.The enhancement in durability and flexibility is primarily due to the dissolution of the brittle phase,along with the shape and dispersal of theγ′phase.

关键词： GH4151 alloy annealing treatment res.dual stres. precipitation evolution strength mechanical properties

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FusionNN:A Semantic Feature Fusion Model Based on Multimodal for Web Anomaly Detection

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Computers, Materials & Continua 2024年第5期79卷 2991-3006页

作者： Li Wang Mingshan Xia Hao Hu Jianfang Li Fengyao Hou Gang Chen Institute of high Energy Physics Chinese Academy of SciencesBeijing100049China Spallation Neutron Source Science center(SNSSC) Dongguan523803China School of Nuclear Technology University of Chinese Academy of SciencesBeijing100049Chin

With the rapid development of the mobile communication and the Internet,the previous web anomaly detectionand identificationmodels were built relying on security experts’empirical knowledge and attack *** approach can achieve higher detection performance,it requires.huge human labor and res.urces to maintainthe feature *** contrast,semantic feature engineering can dynamically discover new semantic features.nd optimize feature selection by automatically analyzing the semantic information contained in the data itself,thus reducing dependence on prior ***,current semantic features.still have the problem ofsemantic expres.ion singularity,as they are extracted from a single semantic mode such as word segmentation,character segmentation,or arbitrary semantic feature *** paper extracts features.of web requestsfrom dual semantic granularity,and proposes a semantic feature fusion method to solve the above *** first preprocesses web requests,and extracts word-level and character-level semantic features.of URLs viaconvolutional neural network(CNN),*** constructing three loss functions to reduce losses betweenfeatures.labels and *** on the HTTP CSIC 2010,Malicious URLs and HttpParams datasetsverify the *** show that compared withmachine learning,deep learningmethods and BERTmodel,the proposed method has better detection *** it achieved the best detection rate of 99.16%in the dataset HttpParams.

关键词： Feature fusion web anomaly detection multimodal convolutional neural network(CNN) semantic feature extraction

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Optimizing high-coordination shell of Co-based single-atom catalysts for efficient ORR and zinc-air batteries

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Journal of Energy Chemistry 2024年第8期95卷 306-314,I0007页

作者： Yugang Qi Qing Liang Kexin Song Xinyan Zhou Meiqi Liu Wenwen Li Fuxi Liu Zhou Jiang Xu Zou Zhongjun Chen Wei Zhang Weitao Zheng Key Laboratory of Automobile Materials MOE School of Materials Science&Engineering Electron Microscopy Centerand International Center of Future ScienceJilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy MaterialsJilin UniversityChangchun 130012JilinChina Institute of high Energy Physics Chinese Academy of SciencesBeijing 100049China

Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic *** the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of ***,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery *** introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,res.lting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,res.onsible for the increased intrinsic *** discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.

关键词： Electrocatalytic Oxygen reduction reaction Single atom catalyst Shell coordination optimization

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Implications of the Stellar Mass Density of high-z Massive Galaxies from JWST on Warm Dark Matter

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res.arch in Astronomy and Astrophysics 2024年第1期24卷 128-134页

作者： Hengjie Lin Yan Gong Bin Yue Xuelei Chen National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Science center for China Space Station Telescope National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Department of Physics College of SciencesNortheastern UniversityShenyang 110819China center for high Energy Physics Peking UniversityBeijing 100871China

A significant excess of the stellar mass density at high redshift has been discovered from the early data release of James Webb Space Telescope(JWST),and it may require a high star formation ***,this will lead to large number density of ionizing photons in the epoch of reionization(EoR),so that the reionization history will be changed,which can arise tension with the current EoR *** dark matter(WDM),via the free streaming effect,can suppres. the formation of small-scale structure as well as low-mass *** provides an effective way to decrease the ionizing photons when considering a large star formation efficiency in high-z massive galaxies without altering the cosmic reionization *** the other hand,the constraints on the properties of WDM can be derived from the JWST *** this work,we study WDM as a possible solution to reconcile the JWST stellar mass density of high-z massive galaxies and reionization *** find that,the JWST high-z comoving cumulative stellar mass density alone has no significant preference for either CDM or WDM *** using the observational data of other stellar mass density measurements and reionization history,we obtain that the WDM particle mass with mw=0.51_(-0.12)^(+0.22) keV and star formation efficiency parameter f_(*)^(0)> 0.39 in 2σ confidence level can match both the JWST high-z comoving cumulative stellar mass density and the reionization history.

关键词： Cosmology (cosmology:)dark matter (cosmology:)large-scale structure of universe

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Synthesis and nitrogen content regulation of diamond in a high-pressure hydrogen-rich environment

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Chinese Physics B 2024年第6期33卷 541-546页

作者：黄国锋陈良超房超 Inner Mongolia Key Laboratory of high-pressure Phase Functional Materials Chifeng UniversityChifeng 024000China Key Laboratory of Material Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China

The regulating nitrogen content of diamond in a hydrogen-rich high-temperature and high-pressure(HPHT) growth environment was systematically investigated in this work by developing three growth systems,namely, "FeNi+Ti", "FeNi+G_(3)N_(6)H_(6)",and "FeNi+Ti+C_(3)N_(6)H_(6)".Optical microscopy,infrared spectroscopy,and photoluminescence(PL)spectroscopy measurements were conducted to analyze the spectroscopic characteristics of diamonds grown in these three *** our analysis,it was demonstrated that the pres.nce of hydrogen in the sp^(3) hybrid C-H does not directly affect the color of the diamond and facilitates the increase of the nitrogen-vacancy(NV) center concentration in a highnitrogen-content *** addition,titanium plays an important role in nitrogen removal,while its impact on hydrogen doping within the diamond lattice is *** importantly,by regulating the ratio of nitrogen impurities that coexist in the nitrogen and hydrogen HPHT environment,the production of hydrogenous Ⅱa-type diamond,hydrogenous Ib-type diamond,and hydrogenous high-nitrogen-type diamonds was achieved with a nitrogen content of less than 1 ppm to 1600 ppm.

关键词： diamond HPHT superhard material hydrogen-rich environment

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Creep constitutive model considering nonlinear creep degradation of fractured rock

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International Journal of Mining Science and Technology 2024年第1期34卷 105-116页

作者： Wang Chunping Liu Jianfeng Chen Liang Liu Jian Wang Lu Liao Yilin beijing res.arch Institute of Uranium Geology Beijing 100029China CAEA Innovation center for Geological Disposal of high-Level Radioactive Waste Beijing 100029China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China School of Architecture and Civil Engineering Xihua UniversityChengdu 610039China

Stability analysis of underground constructions requires.a model study of rock masses’ long-term performance. Creep tests under different stres. conditions was conducted on intact granite and granite samples fractured at 30° and 45° angles. The experimental res.lts indicate that the steady creep strain rates of intact and fractured rock pres.nt an exponential increase trend with the increase of stres. level. A nonlinear creep model is developed based on the experimental res.lts, in which the initial damage caused by fracture together with the damage caused by constant load have been taken into consideration. The fitting analysis res.lts indicated that the model proposed is more accurate at identifying the full creep regions in fractured granite, especially the accelerated stage of creep deformation. The least-square fit error of the proposed creep model is significantly lower than that of Nishihara model by almost an order of magnitude. An analysis of the effects of elastic modulus, viscosity coefficient, and damage factors on fractured rock strain rate and creep strain is conducted. If no consideration is given to the effects of the damage, the proposed nonlinear creep model can degenerate into to the classical Nishihara model.

关键词： Fractured rock Damage Creep Beishan granite Geological disposal

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high-pressure Behavior of Ferromagnesite(Mg_(0.81)Fe_(0.19))CO_(3)by Synchrotron X-Ray Diffraction and Raman Spectroscopy up to 53 GPa

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Journal of Earth Science 2024年第2期35卷 525-535页

作者： Lin Liang Guibin Zhang Shengxuan Huang Jingjing Niu Dongzhou Zhang Jingui Xu Wen Liang Shan Qin Key Laboratory of Orogenic Belts and Crustal Evolution MOEand School of Earth and Space SciencesPeking UniversityBeijing100871China CAS center of Excellence in Tibetan Plateau Earth Sciences and Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China Hawai’i Institute of Geophysics and Planetology School of Ocean and Earth Science and TechnologyUniversity of Hawai’i at ManoaHawai’i96822USA Key Laboratory of high Temperature and high pressure Study of the Earth’s Interior Institute of GeochemistryChinese Academy of SciencesGuiyang550081China

Ferromagnesite(Mg,Fe)CO_(3)with 20 mol%iron is a potential host mineral for carbon transport and storage in the Earth *** high-pressure behavior of synthetic ferromagnesite(Mg_(0.81)Fe_(0.19))CO_(3)up to 53 GPa was investigated by synchrotron X-ray diffraction(XRD)and Raman *** iron bearing carbonate underwent spin transition at around 44–46 GPa accompanied by a volume collapse of 1.8%,which also demonstrated a variation in the dνi/dP slope of the Raman *** pressure-volume data was fitted by a third-order Birch-Murnaghan equation of state(BM-EoS)for the high spin *** best-fit K_(0)=108(1)GPa and K_(0)'=4.2(1).Combining the dνi/dP and the K_(0),the mode Grüneisen parameters of each vibrational mode(T,L,ν4 andν1)were *** effects of iron concentration on the Mg_(1−x)Fe_(x)CO_(3)system related to high-pressure compres.ibility and vibrational properties are *** res.lts expand the knowledge of the physical properties of carbonates and provide insights to the potential deep carbon host.

关键词： ferromagnesite synchrotron XRD Raman spectroscopy high pressure geochemistry mineral

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Revealing structure correlation between ionic liquid and metal-organic framework matrix

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Magnetic res.nance Letters 2024年第2期4卷 65-72页

作者： Ligang Xu Wenda Zhang Chenjie Lou Chenxu Geng Yuxiu Sun Jie Liu Yongchao Shi Huajie Luo Jipeng Fu Haiyan Zheng Mingxue Tang center for high pressure Science and Technology Advanced res.arch Beijing100193China College of Materials Science and Engineering Guilin University of TechnologyGuilin541004China State Key Laboratory of Separation Membranes and Membrane Processes School of Material Science and EngineeringTiangong UniversityTianjin300387China University of Science and Technology beijing Beijing100083China Key Laboratory of Rare Earth Optoelectronic Materials and Devices of Zhejiang Province Institute of Optoelectronic Materials and DevicesChina Jiliang UniversityHangzhou310018China

Solid-state batteries are rising rapidly in res.onse to the fast-increasing energy ***-organic framework(MOF) loaded with ionic liquids has brought new opportunities for solid-state batteries owing to its good interfacial compatibility and high ionic conductivity. MOF-808 is selected to be filled with Li-contained ionic liquid for structure and ion dynamics investigation using nuclear magnetic res.nance(NMR) and X-ray *** study finds that the introduced ionic liquid would partially soften the matrix of MOF-808 and thus yield amorphous phase. By selective isotope replacement under cycling symmetric ^(6)Li metal cell, Li^(+)ion is observed to mainly go cross ionic liquid in the open channel of matrix under potential polarization.

关键词： Nuclear magnetic res.nance Solid-state batteries MOF-808 Ionic liquid Local structure

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Microstructure and Oxidation Behavior of ZrB_(2)-SiC Ceramics Fabricated by Tape Casting and Reactive Melt Infiltration

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无机材料学报 2024年第8期39卷 955-964页

作者： TAN Min CHEN Xiaowu YANG Jinshan ZHANG Xiangyu KAN Yanmei ZHOU Haijun XUE Yudong DONG Shaoming State Key Laboratory of high Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

ZrB_(2)-based ceramics typically necessitate high temperature and pressure for sintering,whereas ZrB_(2)-SiC ceramics can be fabricated at 1500℃using the process of reactive melt infiltration with *** comparison to the conventional preparation method,reactive synthesis allows for the more facile production of ultra-high temperature ceramics with fine particle size and homogeneous *** this work,ZrSi_(2),B4C,and C were used as raw materials to prepare ZrB_(2)-SiC via combination of tape casting and reactive melt infiltration herein referred to as ZBC *** sample of ZrB_(2)-SiC was also prepared using ZrB_(2) and SiC as raw materials through an identical process designated as ZS *** analysis of both ceramic groups revealed smaller and more uniformly distributed particles of the ZrB_(2) phase in ZBC ceramics compared to the larger particles in ZS *** sets of ceramics underwent cyclic oxidation testing in the air at 1600℃for a cumulative duration of 5 cycles,each cycle lasting 2 *** of the oxidation behavior showed that both ZBC ceramics and ZS ceramics developed a glassy SiO_(2)-ZrO_(2) oxide layer on their surfaces during the *** layer severed as a barrier against *** ZBC ceramics,ZrO_(2) is finely distributed in SiO_(2),whereas in ZS ceramics,larger ZrO_(2) particles coexist with glassy SiO_(2).The surface oxide layer of ZBC ceramics maintains a dense structure because the well-dispersed ZrO_(2) increases the viscosity of glassy SiO_(2),preventing its crystallization during the ***,some SiO_(2) in the oxide layer of ZS ceramics may crystallize and form a eutectic with ZrO_(2),leading to the formation of ZrSiO_(4).This leads to cracking of the oxide layer due to differences in thermal expansion coefficients,weakening its barrier *** analysis of the oxidation res.stance shows that ZBC ceramics exhibit less increase in oxide layer thickness and mass compared to ZS ceramics,su

关键词： ultra-high temperature ceramic ZrB2-SiC oxidation behavior reactive melt infiltration

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Human radiological safety assessment for petawatt laser-driven ion acceleration experiments in CLAPA-T

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Matter and Radiation at Extremes 2024年第4期9卷 8-15页

作者： Xiaopeng Zhang Jiarui Zhao Shengxuan Xu Xun Chen Ying Gao Shiyou Chen Kun Zhu Xueqing Yan Wenjun Ma State Key Laboratory of Nuclear Physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsCASBeijing 100049China beijing Laser Acceleration Innovation center HuairouBeijing 101400China Institute of Guangdong Laser Plasma Technology BaiyunGuangzhou 510540China

The newly built Compact Laser Plasma Accelerator-Therapy facility at Peking University will deliver 60 J/1 Hz laser pulses with 30 fs *** by this petawatt laser facility,proton beams with energy up to 200 MeV are expected to be generated for tumor *** high-repetition operation,both prompt radiation and res.dual radiation may cause safety ***,human radiological safety assessment before commissioning is *** this paper,we simulate both prompt and res.dual radiation using the Geant4 and FLUKA Monte Carlo codes with reasonable proton and as-produced electron beam *** find that the prompt radiation can be shielded well by the concrete wall of the experimental hall,but the risk from res.dual radiation is nonnegligible and necessitates adequate radiation *** the basis of the simulation res.lts,we discuss the constraints imposed by radiation safety considerations on the annual working time,and we propose radiation cooling strategies for different shooting modes.

关键词： laser prompt acceleration

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