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Micro defects formation and dynamic response analysis of steel plate of quasi-cracking area subjected to explosive load

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Defence Technology（防务技术） 2024年第1期31卷 580-593页

作者： Zheng-qing Zhou Ze-chen Du Xiao Wang Hui-ling Jiang Qiang Zhou Yu-long zhang Yu-zhe Liu pei-ze zhang Research Institute of Macro-Safety Science University of Science and TechnologyBeijing100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China School of Mechanical Engineering Nantong UniversityNantong226019China China North Industry Advanced Technology Generalization Institute Beijing100089China China Academy of Ordnance Science China

As the protective component,steel plate had attracted extensive attention because of frequently threats of explosive loads.In this paper,the evolution of microstructure and the mechanism of damage in the quasi-cracking area of steel plate subjected to explosive load were discussed and the relationships between micro defects and dynamic mechanical response were revealed.After the explosion experiment,five observation points were selected equidistant from the quasi-cracking area of the section of the steel plate along the thickness direction,and the characteristics of micro defects at the observation points were analyzed by optical microscope(OM),scanning electron microscope(SEM) and electron backscattered diffraction(EBSD).The observation result shows that many slip bands(SBs) appeared,and the grain orientation changed obviously in the steel plate,the two were the main damage types of micro defects.In addition,cracks,peeling pits,grooves and other lager micro defects were appeared in the lower area of the plate.The stress parameters of the observation points were obtained through an effective numerical model.The mechanism of damage generation and crack propagation in the quasicracking area were clarified by comparing the specific impulse of each observation point with the corresponding micro defects.The result shows that the generation and expansion of micro defects are related to the stress area(i.***.the upper compression area,the neutral plane area,and the lower tension area).The micro defects gather and expand at the grain boundary,and will become macroscopic damage under the continuous action of tensile stress.Besides,the micro defects at the midpoint of the section of the steel plate in the direction away from the explosion center(i.***.the horizontal direction) were also studied.It was found that the specific impulse at these positions were much smaller than that in the thickness direction,the micro defects were only SBs and a few micro cracks,and the those decreased with the increase of the distance from the e

关键词： Explosive load Quasi-cracking area Micro defects Steel plate Dynamic response Numerical simulation

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Effective assignment of positional isomers in dimeric shikonin and its analogs by ^(1)H NMR spectroscopy

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Chinese Chemical Letters 2024年第5期35卷 223-226页

作者： ling-Hao Zhao Hai-Wei Yan Jian-Shuang Jiang Xu zhang Xiang Yuan Ya-Nan Yang pei-Cheng zhang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

An approach for distinguishing two types of positional isomers of dimeric shikonin and its analogs was explored with ^(4)JC,H long-range correlation by prolonging the acquisition time at ^(2,3)JC,H values of 2.0 and 8.0Hz.Furthermore,the ^(1)H(proton)nuclear magnetic resonance(NMR)pattern of phenolic hydroxyl protons was developed as a“diagnosis signal”to ascertain the relative location of each side chain in DMSO-d_(6) at sample concentrations of 0.022-0.034 mol/L.The chemical shift differences of 0.6ppm between OH-5' and OH-1 and between OH-8'and OH-4 are assigned to Type A and Type B,respectively.All reported ambiguous structures were corrected by this pattern.Additionally,the steric structures of isolated compounds were elucidated by quantum chemical calculations of electronic circular dichroism(ECD)spectra.

关键词： Arnebia euchroma Dimeric hydroxyl naphthoquinones Positional isomers ^(1)H NMR spectroscopy Chemical shift difference

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Dynamic recrystallization mechanism, texture evolution development and mechanical characteristics of a Mg–8.7Gd–4.18Y–0.42Zr magnesium alloy by ECAP

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Progress in Natural Science:Materials International 2024年第2期34卷 376-388页

作者： ling zhang Yinglong Li School of Materials Science and Engineering Northeastern University School of Mechanical and Engineering Ningxia Institute of Science and Technology

Equal channel angle pressing is recognized for its ability to refine alloy grains and alter grain orientation, thereby achieve better mechanical performance of the magnesium alloy. This study investigates the microstructures,dynamic recrystallization mechanism, texture development, and mechanical performance of GW94K(Mg–8.7Gd–4.18Y–0.42Zr wt. %) Mg alloy following ECAP-4 passes at 400°C and 3 mm/min. Results show that when high-temperature deformation is undertaken, twin formation is suppressed while dislocation slip is facilitated, increasing dislocation density during deformation. Following ECAP deformation, the sample displayed higher fracture elongation, TYS, and UTS than the as-solutioned GW94K alloy. In particular, the GW94K alloy performed well mechanically after ECAP-4 passes, with an ultimate TYS of 231 MPa, an UTS of 290 MPa, and an elongation of 14.8 %. DDRX and shear bands induce CDRX, both of which are important in plastic deformation. as well as in modifying microstructure and grain orientation during ECAP deformation.

关键词： Dynamic recrystallization mechanism Equal channel angular pressing Magnesium alloy Mechanical performance Mg-Gd-Y-Zr alloy Texture development

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A passive sampler for synchronously measuring inorganic and organic pollutants in sediment porewater:Configuration and field application

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Journal of Environmental Sciences 2024年第2期136卷 201-212页

作者： pei Lei Mingying Chen Nan Rong Wenzhong Tang Hong zhang School of Environment Nanjing Normal UniversityNanjing 210023China State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China South China Institute of Environmental Sciences Ministry of Ecology and EnvironmentGuangzhou 510530China State Environmental Protection Key Laboratory of Water Environmental Simulation and Pollution Control Guangzhou 510530China University of Chinese Academy of Sciences Beijing 100049China

In situ measurement of multiple pollutants coexisting in sediment porewater is an essential step in comprehensively assessing the bioavailability and risk of pollutants,but to date,this needs to be better developed.In this study,a passive sampler,consisting of an“I-shaped”supporting frame and inorganic/organic sampling units,incorporating equilibrium dialysis theory and kinetic/equilibrium sorption principle,was developed for the synchronous measurement of inorganic(e.g.,phosphorus and metal(loid)s)and organic pollutants(e.g.,parent and substituted PAHs).The equilibrium time and sampling rates were explored in laboratory tests to support in situ application.Profiles of pollutants in porewater within a vertical resolution of centimeters,i.e.,1 cm and 2 cm for inorganic and organic pollutants,respectively,were obtained by field deployment of the sampler for further estimation of diffusive fluxes across the sediment-water interface.The results suggested that the role of sediments for a specific pollutant may change(e.g.,from“sink”to“source”)during the sampling time.This study demonstrated the feasibility of synchronous measurement of inorganic and organic pollutants in sediment porewater by the passive sampler.In addition,it provided new insight for further investigation into the combined pollution effects of various pollutants in sediments.

关键词： Passive sampling Bioavailability Polycyclic aromatic hydrocarbons Combined pollution Diffusive flux

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MODIFIED STOCHASTIC EXTRAGRADIENT METHODS FOR STOCHASTIC VARIATIONAL INEQUALITY

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Journal of Computational Mathematics 2024年第2期42卷 390-414页

作者： ling zhang lingling Xu School of Management and Economic Beijing Institute of TechnologyBeijing 100081China School of Mathematical Sciences Nanjing Normal UniversityNanjing 210023China School of Mathematical Sciences and Jiangsu Key Laboratory for NSLSCS Nanjing Normal UniversityNanjing 210023China

In this paper,we consider two kinds of extragradient methods to solve the pseudo-monotone stochastic variational inequality problem.First,we present the modified stochastic extragradient method with constant step-size(MSEGMC)and prove the convergence of it.With the strong pseudo-monotone operator and the exponentially growing sample sequences,we establish the R-linear convergence rate in terms of the mean natural residual and the oracle complexity O(1/ǫ).Second,we propose a modified stochastic extragradient method with adaptive step-size(MSEGMA).In addition,the step-size of MSEGMA does not depend on the Lipschitz constant and without any line-search procedure.Finally,we use some numerical experiments to verify the effectiveness of the two algorithms.

关键词： Stochastic variational inequality Pseudo-monotone Modified stochastic ex-tragradient methods Adaptive step-size

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Multi-instance partial-label learning: towards exploiting dual inexact supervision

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Science China(Information Sciences) 2024年第3期67卷 48-61页

作者： Wei TANG Weijia zhang Min-ling zhang School of Computer Science and Engineering Southeast University Key Laboratory of Computer Network and Information Integration (Southeast University) Ministry of Education School of Information and Physical Sciences The University of Newcastle

Weakly supervised machine learning algorithms are able to learn from ambiguous samples or labels, e.g., multi-instance learning or partial-label learning. However, in some real-world tasks, each training sample is associated with not only multiple instances but also a candidate label set that contains one groundtruth label and some false positive labels. Specifically, at least one instance pertains to the ground-truth label while no instance belongs to the false positive labels. In this paper, we formalize such problems as multi-instance partial-label learning(MIPL). Existing multi-instance learning algorithms and partial-label learning algorithms are suboptimal for solving MIPL problems since the former fails to disambiguate a candidate label set, and the latter cannot handle a multi-instance bag. To address these issues, a tailored algorithm named MIPLGP, i.e., multi-instance partial-label learning with Gaussian processes, is proposed.MIPLGP first assigns each instance with a candidate label set in an augmented label space, then transforms the candidate label set into a logarithmic space to yield the disambiguated and continuous labels via an exclusive disambiguation strategy, and last induces a model based on the Gaussian processes. Experimental results on various datasets validate that MIPLGP is superior to well-established multi-instance learning and partial-label learning algorithms for solving MIPL problems.

关键词： machine learning multi-instance partial-label learning multi-instance learning partial-label learning Gaussian processes

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The roles of macrophage migration inhibitory factor in retinal diseases

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Neural Regeneration Research 2024年第2期19卷 309-315页

作者： Hongbing zhang Xianjiao zhang Hongsong Li Bing Wang pei Chen Jiamin Meng Shaanxi Institute of Ophthalmology Xi’anShaanxi ProvinceChina Department of Ophthalmology First Affiliated Hospital of Northwest UniversityXi’anShaanxi ProvinceChina Department of Pathology First Affiliated Hospital of Northwest UniversityXi’anShaanxi ProvinceChina

Macrophage migration inhibitory factor(MIF),a multifunctional cytokine,is secreted by various cells and participates in inflammatory reactions,including innate and adaptive immunity.There are some evidences that MIF is involved in many vitreoretinal diseases.For example,MIF can exacerbate many types of uveitis;measurements of MIF levels can be used to monitor the effectiveness of uveitis treatment.MIF also alleviates trauma-induced and glaucoma-induced optic nerve damage.Furthermore,MIF is critical for retinal/choroidal neovascularization,especially complex neovascularization.MIF exacerbates retinal degeneration;thus,anti-MIF therapy may help to mitigate retinal degeneration.MIF protects uveal melanoma from attacks by natural killer cells.The mechanism underlying the effects of MIF in these diseases has been demonstrated:it binds to cluster of differentiation 74,inhibits the c-Jun N-terminal kinase pathway,and triggers mitogen-activated protein kinases,extracellular signal-regulated kinase-1/2,and the phosphoinositide-3-kinase/Akt pathway.MIF also upregulates Toll-like receptor 4 and activates the nuclear factor kappa-B signaling pathway.This review focuses on the structure and function of MIF and its receptors,including the effects of MIF on uveal inflammation,retinal degeneration,optic neuropathy,retinal/choroidal neovascularization,and uveal melanoma.

关键词： diabetic retinopathy glaucoma macrophage migration inhibitory factor migration inhibitory factor receptor optic neuropathy retinal degeneration retinal neovascular uveal melanoma uveitis

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Light(Science & Applications) 2024年第2期13卷 333-346页

作者： Yifan Sun Qian Li ling-Jun Kong Xiangdong zhang Key Laboratory of advanced optoelectronic quantum architecture and measurements of Ministry of Education Beijing Key Laboratory of Nanophotonics&Ultrafine Optoelectronic SystemsSchool of PhysicsBeijing Institute of Technology100081BeijingChina

Compared with electrical neural networks,optical neural networks(ONNs)have the potentials to break the limit of the bandwidth and reduce the consumption of energy,and therefore draw much attention in recent years.By far,several types of ONNs have been implemented.However,the current ONNs cannot realize the acceleration as powerful as that indicated by the models like quantum neural networks.How to construct and realize an ONN with the quantum speedup is a huge challenge.Here,we propose theoretically and demonstrate experimentally a new type of optical convolutional neural network by introducing the optical correlation.It is called the correlated optical convolutional neural network(COCNN).We show that the COCNN can exhibit“quantum speedup”in the training process.The character is verified from the two aspects.One is the direct illustration of the faster convergence by comparing the loss function curves of the COCNN with that of the traditional convolutional neural network(CNN).Such a result is compatible with the training performance of the recently proposed quantum convolutional neural network(QCNN).The other is the demonstration of the COCNN’s capability to perform the QCNN phase recognition circuit,validating the connection between the COCNN and the QCNN.Furthermore,we take the COCNN analog to the 3-qubit QCNN phase recognition circuit as an example and perform an experiment to show the soundness and the feasibility of it.The results perfectly match the theoretical calculations.Our proposal opens up a new avenue for realizing the ONNs with the quantum speedup,which will benefit the information processing in the era of big data.

关键词： process quantum convolution

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Fantastic voyage: The journey of NLRP3 inflammasome activation

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Genes & Diseases 2024年第2期11卷 819-829页

作者： Xiangyong Que Sihao Zheng Qibin Song Huadong pei Pingfeng zhang Cancer Center Renmin Hospital of Wuhan UniversityWuhanHubei 430060China Department of Oncology Georgetown Lombardi Comprehensive Cancer CenterGeorgetown University Medical CenterWashingtonDC 20057USA

NLRP3 inflammasome,an intracellular multiprotein complex,can be activated by a range of pathogenic microbes or endogenous hazardous chemicals.Its activation results in the release of cytokines such as IL-1β and IL-18,as well as Gasdermin D which eventually causes pyroptosis.The activation of NLRP3 inflammasome is under strict control and regulation by numerous pathways and mechanisms.Its excessive activation can lead to a persistent inflammatory response,which is linked to the onset and progression of severe illnesses.Recent studies have revealed that the subcellular localization of NLRP3 changes significantly during the activation process.In this review,we review the current understanding of the molecular mechanism of NLRP3 inflammasome activation,focusing on the subcellular localization of NLRP3 and the associated regulatory mechanisms.We aim to provide a comprehensive understanding of the dynamic transportation,activation,and degradation processes of NLRP3.

关键词： Inflammasome activation Innate immunity NLRP3 NLRP3 inflammasome Subcellular localization

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Advances in methane emissions from agricultural sources:Part I.Accounting and mitigation

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Journal of Environmental Sciences 2024年第6期140卷 279-291页

作者： Xiaokun Wu Ying zhang Yinghui Han Yagang zhang Yuhang zhang Xiaodan Cheng pei Zhong Xue Yuan Yuanxun zhang Zhengqiang Li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071003China College of Resources and Environment University of Chinese Academy of SciencesBeijing 101408China Interdisciplinary Mathematics Institute University of South CarolinaColumbiaSC 29208United States Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

Methane is one of the major greenhouse gases(GHGs)and agriculture is recognized as its primary emitter.Methane accounting is a prerequisite for developing effective agriculture mitigation strategies.In this review,methane accounting methods and research status for various agricultural emission source including rice fields,animal enteric fermentation and livestock and poultry manure management were overview,and the influencing factors of each emission source were analyzed and discussed.At the same time,it analyzes the different research efforts involving agricultural methane accounting and makes recommendations based on the actual situation.Finally,mitigation strategies based on accounting results and actual situation are proposed.This review aims to provide basic data and reference for agriculture-oriented countries and regions to actively participate in climate action and carry out effective methane emission mitigation.

关键词： Methane emission Agricultural sources Accounting methodology Mitigation Emission influencing factors

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