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Atomistic study of inverse size effect induced by interfacial plasticity in pearlitic multi-principal element alloy

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Rare Metals 2024年第7期43卷 3341-3355页

作者： chen Yang Qiao-Sheng Xia Cun-Hong yin Dong-Peng Hua College of Mechanical Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Advanced Manufacturing Technology Ministry of EducationGuizhou UniversityGuiyang 550025China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China

Owing to the fine nano-laminated structure,the pearlitic multi-principal element alloy(PMPEA) exhibits excellent mechanical and tribological ***,the incomplete understanding of the size effect of its lamella thickness and the unclear understanding of the plasticity-interface interaction mechanism limit further optimization of *** this study,the FeCoNi/Ni_3Ti interface-mediated plastic deformation behavior in PMPEA and the variation of mechanical and tribological properties with lamella thickness within the nanoscale range using molecular dynamics(MD) simulation were *** results indicate that the mechanical and tribological properties of the PMPEA with lamella thicknesses below 10 nm have a significant inverse size effect,i.e.,the smaller the lamella thickness,the weaker the *** is because the plastic carrier-interface interaction mechanism changes from a strengthening mechanism that hinders dislocations to a weakening mechanism that promotes dislocations with the decreases in the lamella thickness,and the weakening effect becomes more pronounced as the lamella thickness decreases and the number of interfaces *** particular,the deformation behavior of Ni_3Ti lamellae changes from crystal-like to amorphous-like with decreasing ***,in the sample with larger lamella thickness,the occurrence of hierarchical slips in the body-centered cubic(BCC) phase due to the multiprincipal elements effect can better alleviate the stress concentration caused by the dislocation accumulation at the interface,so that the phase interface exhibits outstanding load-bearing *** the dislocation pattern in BCC phase shows a firm high-density cell,which makes the substrate exhibit a stable tribological response.

关键词： Multi-principal element alloy Nano-laminated structure Molecular dynamics simulation Nanoindentation and nanoscratch

A novel strategy of tannery sludge disposal–converting into biochar and reusing for Cr(Ⅵ)removal from tannery wastewater

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Journal of Environmental Sciences 2024年第4期138卷 637-649页

作者： Zhiwei Li Di yu Xingdong Wang Xuejiao Liu Zhen Xu yin Wang CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control CAS Haixi Industrial Technology Innovation Center in BeilunNingbo 315830China Key Laboratory of Urban Environment and Health Ningbo Observatio

Tannery sludge with high chromium content has been identified as hazardous solid waste due to its potential toxic *** safety disposal and valorization of the tannery sludge remains a *** this study,the chromium stabilization mechanism was systematically investigated during chromium-rich tannery sludge was converted to biochar and the removal performance of the sludge biochar(SBC)for Cr(Ⅵ)from tannery wastewater was also *** results showed that increase in pyrolysis temperature was conductive to the stabilization of Cr and significant reduction of the proportion of Cr(Ⅵ)in *** was confirmed that the stabilization of chromium mainly was attributed to the embedding of chromium in the C matrix and the transformation of the chromium-containing substances from the amorphous Cr(OH)_(3)to the crystalline state,such as(FeMg)Cr_(2)O_(5).The biochar presented high adsorption capacity of Cr(Ⅵ)at low pH and the maximal theoretical adsorption capacity of SBC produced at 800°C can reach 352 mg Cr(Ⅵ)/g,the process of which can be well expressed by Langmuir adsorption isotherm and pseudo second order *** electrostatic effect and reduction reaction were dominantly responsible for the Cr(Ⅵ)adsorption by ***,this study provided a novel strategy for the harmless disposal and resource utilization for the solid waste containing chromium in leather industry.

关键词： Chromium-rich tannery sludge Pyrolysis Biochar Stabilizationmechanisms Cr(Ⅵ)adsorption

Understanding and improving fairness in cognitive diagnosis

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Science China(Information Sciences) 2024年第5期67卷 99-114页

作者： Zheng ZHANG Le WU Qi LIU Jiayu LIU Zhenya HUANG yu yin Yan ZHUANG Weibo GAO Enhong chen Anhui Province Key Laboratory of Big Data Analysis and Application School of Computer Science and Technology& School of Data Science University of Science and Technology of China State Key Laboratory of Cognitive Intelligence School of Computer Science and Information Engineering Hefei University of Technology

Intelligent education is a significant application of artificial intelligence. One of the key research topics in intelligence education is cognitive diagnosis, which aims to gauge the level of proficiency among students on specific knowledge concepts(e.g., Geometry). To the best of our knowledge, most of the existing cognitive models primarily focus on improving diagnostic accuracy while rarely considering fairness issues; for instance, the diagnosis of students may be affected by various sensitive attributes(e.g., region). In this paper,we aim to explore fairness in cognitive diagnosis and answer two questions:(1) Are the results of existing cognitive diagnosis models affected by sensitive attributes?(2) If yes, how can we mitigate the impact of sensitive attributes to ensure fair diagnosis results? To this end, we first empirically reveal that several wellknown cognitive diagnosis methods usually lead to unfair performances, and the trend of unfairness varies among different cognitive diagnosis models. Then, we make a theoretical analysis to explain the reasons behind this phenomenon. To resolve the unfairness problem in existing cognitive diagnosis models, we propose a general fairness-aware cognitive diagnosis framework, FairCD. Our fundamental principle involves eliminating the effect of sensitive attributes on student proficiency. To achieve this, we divide student proficiency in existing cognitive diagnosis models into two components: bias proficiency and fair *** design two orthogonal tasks for each of them to ensure that fairness in proficiency remains independent of sensitive attributes and take it as the final diagnosed result. Extensive experiments on the Program for International Student Assessment(PISA) dataset clearly show the effectiveness of our framework.

关键词： fairness intelligent education cognitive diagnosis psychometrics adversarial learning

Generic Existence of Infinitely Many Non-contractible Closed Geodesics on Compact Space Forms

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1674-1684页

作者： Hui Liu yu chen Wang School of Mathematics and Statistics Wuhan UniversityWuhan430072P.R.China School of Mathematics Tianjin Normal UniversityTianjin300384P.R.China

Let M=S^(n)/Γand h be a nontrivial element of finite order p inπ_(1)(Μ),where the integers n,p≥2,Γis a finite abelian group which acts freely and isometrically on the n-sphere and therefore M is diffeomorphic to a compact space *** this paper,we prove that there are infinitely many non-contractible closed geodesics of class[h]on the compact space form with C^(r)-generic Finsler metrics,where 4≤r≤∞.The conclusion also holds for Cr-generic Riemannian metrics for 2≤r≤∞.The proof is based on the resonance identity of non-contractible closed geodesics on compact space forms.

关键词： Compact space forms non-contractible closed geodesics generic Finsler metrics resonance identity

An assessment of the CMIP6 performance in simulating Arctic sea ice volume flux via Fram Strait

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Advances in Climate Change Research 2024年第4期15卷 584-595页

作者： Hui-Yan KUANG Shao-Zhe SUN yu-Fang YE Shao-yin WANG Hai-Bo BI Zhuo-Qi chen Xiao chenG School of Geospatial Engineering and Science Sun Yat-sen UniversitySouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Comprehensive Observation of Polar Environment(Sun Yat-sen University) Ministry of EducationZhuhai 519082China CAS Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of Sciences(CAS)Qingdao 266071China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Qingdao 266237China

Numerical models serve as an essential tool to investigate the causes and effects of Arctic sea ice *** the simulation capabilities of the most recent CMIP6 models in sea ice volume flux provides references for model applications and ***,reliable long-term simulation results of the ice volume fux contribute to a deeper understanding of the sea ice response to global climate *** this study,the sea ice volume flux through six Arctic gateways over the past four decades(1979-2014)were estimated in combination of satellite observations of sea ice concentration(SIC)and sea ice motion(SIM)as well as the Pan-Arctic Ice-Ocean Modeling and Assimilation System(PIOMAS)reanalysis sea ice thickness(SIT)*** simulation capability of 17 CMIP6 historical models for the volume flux through Fram Strait were quantitatively *** ice volume flux simulated from the ensemble mean of 17 CMIP6 models demonstrates better performance than that from the individual model,yet IPSL-CM6A-LR and EC-Earth3-Veg-LR outperform the ensemble mean in the annual volume flux,with Taylor scores of 0.86 and 0.50,***6 models display relatively robust capability in simulating the seasonal variations of volume *** them,CESM2-WACCM performs the best,with a correlation coefficient of 0.96 and a Taylor score of ***,NESM3 demonstrates the largest devi-ation from the observation/reanalysis data,with the lowest Taylor score of *** variability of sea ice volume flux is primarily influenced by SIM and SIT,followed by *** extreme large sea ice export through Fram Strait is linked to the occurrence of anomalously low air temperatures,which in turn promote increased SIC and SIT in the corresponding ***,the intensified activity of Arctic cyclones and Arctic dipole anomaly could boost the southward sea ice velocity through Fram Strait,which further enhance the sea ice outflow.

关键词： Sea ice volume flux CMIP6 models Fram Strait Attribution analysis

Pd-Catalyzed Dienylation of Propargylic Esters Enabling Highly Stereoselective Synthesis of Danishefsky-Type Trisubstituted Dienes

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Chinese Journal of Chemistry 2024年第17期42卷 1993-1998页

作者： chen Zhou Mengfu Dai Xiaoyu yin Mingyue Zhang Weijin Gu Liang-An chen Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of New Power BatteriesSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjingJiangsu 210023China

The stereochemical synthesis of highly substituted Danishefsky-type dienes remains unsolved in organic *** describe a simple and efficient approach for the stereoselective synthesis of Danishefsky-type trisubstituted dienes from readily available propargylic esters via Pd-catalyzed dienylation reaction through the key intermediate metallacyclobutene in a regio-,chemo-and stereoselective *** method facilitates a broad range of challenging trisubstituted dienes with a high level of stereocontrol.

关键词： Propargylic ester Dienylation Diene Stereoselectivity Cycloaddition Palladium β-H elimination Regioselectivity

Moyamoya syndrome may result from psoriasis: Four case reports

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World Journal of Clinical Cases 2024年第10期12卷 1830-1836页

作者： Zhi-ying chen Xiao-Qin yu yuan-yuan Xiang Ling-Hua Liu Xiao-Ping yin Department of Neurology The Affiliated Hospital of Jiujiang UniversityJiujiang 332000Jiangxi ProvinceChina Department of Dermatology The Affiliated Hospital of Jiujiang UniversityJiujiang 332000Jiangxi ProvinceChina

BACKGROUND Moyamoya syndrome(MMS)is a group of diseases that involves more than one underlying disease and is accompanied by moyamoya vascular *** is a chronic immune skin disease closely linked to high blood pressure and heart ***,psoriasis-related MMS has not been *** SUMMARY We collected data on patients with stroke due to MMS between January 2017 and December 2019 and identified four cases of *** histories,imaging,and hematological data were *** average age of the initial stroke onset was 58.25±11.52 years;three cases of hemorrhagic and one case of ischemic stroke were *** average duration from psoriasis confirmation to the initial MMS-mediated stroke onset was 17±3.56 *** MMS-related stenoses involved the bilateral cerebral arteries:Suzuki grade III in one case,grade IV in two cases,and grade V in one *** elevated plasma interleukin-6 levels were observed in four *** patients had abnormally elevated immunoglobulin E levels,and two had *** four patients received medication instead of *** an average follow-up time of 2 years,two causing transient ischemic attacks occurred in two patients,and no hemorrhagic events *** Psoriasis may be a potential risk factor for *** with psoriasis should be screened for MMS when they present with neurological symptoms.

关键词： Moyamoya syndrome Psoriasis Stroke Interleukin-6 Immune Hypertension Case report

Heavy ion energy influence on multiple-cell upsets in small sensitive volumes:from standard to high energies

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Nuclear Science and Techniques 2024年第5期35卷 109-121页

作者： Yang Jiao Li-Hua Mo Jin-Hu Yang yu-Zhu Liu Ya-Nan yin Liang Wang Qi-yu chen Xiao-yu Yan Shi-Wei Zhao Bo Li You-Mei Sun Pei-Xiong Zhao Jie Liu Institute of Modern Physics Chinese Academy of ScienceLanzhou 730000China University of Chinese Academy of Science Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China China Electronics Technology Group Corporation No.58 Research Institute Wuxi 214000China Beijing Microelectronics Technology Institute Beijing 100084China Institute of Microelectronics Chinese Academy of SciencesBeijing 100029China Key Laboratory of Science and Technology on Silicon Devices Chinese Academy of SciencesBeijing 100029China

The 28 nm process has a high cost-performance ratio and has gradually become the standard for the field of radiation-hardened ***,owing to the minimum physical gate length of only 35 nm,the physical area of a standard 6T SRAM unit is approximately 0.16μm^(2),resulting in a significant enhancement of multi-cell charge-sharing ***-cell upsets(MCUs)have become the primary physical mechanism behind single-event upsets(SEUs)in advanced nanometer node *** range of ionization track effects increases with higher ion energies,and spacecraft in orbit primarily experience SEUs caused by high-energy ***,ground accelerator experiments have mainly obtained low-energy ion irradiation ***,the impact of ion energy on the SEU cross section,charge collection mechanisms,and MCU patterns and quantities in advanced nanometer devices remains *** this study,based on the experimental platform of the Heavy Ion Research Facility in Lanzhou,low-and high-energy heavy-ion beams were used to study the SEUs of 28 nm SRAM *** influence of ion energy on the charge collection processes of small-sensitive-volume devices,MCU patterns,and upset cross sections was obtained,and the applicable range of the inverse cosine law was *** findings of this study are an important guide for the accurate evaluation of SEUs in advanced nanometer devices and for the development of radiation-hardening techniques.

关键词： 28 nm static random access memory(SRAM) Energy effects Heavy ion Multiple-cell upset(MCU) Charge collection Inverse cosine law

Efficient conversion of acoustic vortex using extremely anisotropic metasurface

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Frontiers of physics 2024年第4期19卷 257-264页

作者： Zhanlei Hao Haojie chen yuhang yin cheng-Wei Qiu Shan Zhu Huanyang chen Institute of Electromagnetics and Acoustics and Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamen 361005China Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3117583Singapore Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China

Vortex wave and plane wave,as two most fundamental forms of wave propagation,are widely applied in various research ***,there is currently a lack of basic mechanism to enable arbitrary conversion between *** this paper,we propose a new paradigm of extremely anisotropic acoustic metasurface(AM)to achieve the efficient conversion from 2D vortex waves with arbitrary orbital angular momentum(OAM)to plane *** underlying physics of this conversion process is ensured by the symmetry shift of AM medium parameters and the directional compensation of ***,this novel phenomenon is further verified by analytical calculations,numerical demonstrations,and acoustic experiments,and the deflection angle and direction of the converted plane waves are qualitatively and quantitatively confirmed by a simple *** work provides new possibilities for arbitrary manipulation of acoustic vortex,and holds potential applications in acoustic communication and OAM-based devices.

关键词： efficient wave conversion vortex wave plane wave orbital angular momentum acoustic metasurface