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Simultaneously enhancing the strength and ductility of as-extruded AlN/AZ91 composites via nano-precipitation and pyramidal slip

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Journal of Materials Science & Technology 2024年第5期172卷 240-254页

作者： Bin Zhang yunxia Sun Tuo Liang Yunzhen Li Tian Li Jingchao Wang Ruiru Cai Changlin yang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

Age hardening is often used to optimize the mechanical properties of as-deformed Mg-based materials in industry,whereas the improvement of strength is usually accompanied by the significant loss of ductility,which hinders the application of Mg-based materials in structural components.In the present work,high strength-ductility synergy(the yield strength of 263±9 MPa,ultimate tensile strength of 398±7 MPa and elongation to fracture of 34%±1%)was realized in as-extruded AlN/AZ91 composites after optimiz-ing aging processes.Microstructural characterization shows that AlN particles induced a large number of geometrically necessary dislocations around the AlN/Mg interface during extrusion,which decreased the nucleation barrier and provided more heterogeneous nucleation sites forγ-Mg 17 Al 12 continuous precipi-tation.Meanwhile,95%of residual dislocations in as-extruded AlN/AZ91 composites were annihilated dur-ing peak-aging,suppressing the growth and coarsening of continuous precipitates.Therefore,high density of nano-sizedγ-Mg 17 Al 12 continuous precipitates was produced in as-extruded AlN/AZ91 composites af-ter peak-aging.During tension,gliding dislocations bypassed sphericalγ-Mg 17 Al 12 nano-precipitates by Orowan looping rather than cutting mechanism,which induced a strong block on dislocation motion.So high yield strength was mainly attributed to the high density of non-shearableγ-Mg 17 Al 12 nano-precipitates with spherical morphology,which was different from other Mg-Al-based systems.The results of texture evolution and slip trace analysis demonstrated that the suppression of extension twinning and less basal slip was due to the enhanced activity of pyramidalc+aslip in as-extruded AlN/AZ91 com-posites after peak-aging during the room temperature tension,meanwhile,the dislocation density of as-extruded AlN/AZ91 composites was significantly decreased during peak-aging,then higher elongation to fracture was achieved.

关键词： Magnesium matrix composites Mechanical properties Precipitation Deformation mechanisms Non-basal slip

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Fast measurement and prediction method for electromagnetic susceptibility of receiver

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Journal of Systems Engineering and Electronics 2024年第2期35卷 275-285页

作者： CHEN Yan LU Zhonghao LIU yunxia State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State Key Laboratory of Astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone test.Firstly,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent analysis.Secondly,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the receiver.An experiment performed on a radar receiver confirms the reliability of the method proposed in this paper.It shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity model.Based on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain power domain

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Influencing Factors and Prediction of Risk of Returning to Ecological Poverty in Liupan Mountain Region,China

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Chinese Geographical Science 2024年第3期34卷 420-435页

作者： CUI yunxia LIU Xiaopeng JIANG Chunmei TIAN Rujun NIU Qingrui School of Geography and Planning Ningxia UniversityYinchuan 750021China Key Laboratory(China-Arab)of Resource Evaluation and Environmental Regulation of Arid Region in Ningxia Yinchuan 750021China

China has resolved its overall regional poverty in 2020 by attaining moderate societal prosperity.The country has entered a new development stage designed to achieve its second centenary goal.However,ecological fragility and risk susceptibility have increased the risk of returning to ecological poverty.In this paper,the Liupan Mountain Region of China was used as a case study,and the counties were used as the scale to reveal the spatiotempora differentiation and influcing factors of the risk of returning to poverty in study area.The indicator data for returning to ecological poverty from 2011-2020 were collected and summarized in three dimensions:ecological,economic and social.The autoregressive integrated moving average model(ARIMA)time series and exponential smoothing method(ES)were used to predict the multidimensional indicators of returning to ecological poverty for 61 counties(districts)in the Liupan Mountain Region for 2021-2030.The back propagation neural network(BPNN)and geographic information system(GIS)were used to generate the spatial distribution and time variation for the index of the risk of returning to ecological poverty(RREP index).The results show that 1)ecological factors were the main factors in the risk of returning to ecological poverty in Liupan Mountain Region.2)The RREP index for the 61 counties(districts)exhibited a downward trend from 2021-2030.The RREP index declined more in medium-and high-risk areas than in low-risk areas.From 2021 to 2025,the RREP index exhibited a slight downward trend.From 2026 to2030,the RREP index was expected to decline faster,especially from 2029-2030.3)Based on the RREP index,it can be roughly divided into three types,namely,the high-risk areas,the medium-risk areas,and the low-risk areas.The natural resource conditions in lowrisk areas of returning to ecological poverty,were better than those in medium-and high-risk areas.

关键词： risk of returning to ecological poverty autoregressive integrated moving average model(ARIMA) exponential smoothing model back propagation neural network(BPNN) Liupan Mountain Region,China

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Oxygen‑Coordinated Single Mn Sites for Efficient Electrocatalytic Nitrate Reduction to Ammonia

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Nano-Micro Letters 2024年第1期16卷 147-159页

作者： Shengbo Zhang Yuankang Zha Yixing Ye Ke Li Yue Lin Lirong Zheng Guozhong Wang yunxia Zhang Huajie Yin Tongfei Shi Haimin Zhang Laboratory of Materials Physics Centre for Environmental and Energy NanomaterialsAnhui Key Laboratory of Nanomaterials and NanotechnologyCAS Center for Excellence in NanoscienceInstitute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031People’s Republic of China University of Science and Technology of China Hefei 230026People’s Republic of China Key Laboratory of Agricultural Sensors Ministry of AgricultureSchool of Information and ComputerAnhui Agricultural UniversityHefei 230026People’s Republic of China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026People’s Republic of China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadBeijing 100049People’s Republic of China

Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental protection.Here,we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen(O)coordination on bacterial cellulose-converted graphitic carbon(Mn-O-C).Evidence of the atomically dispersed Mn-(O-C_(2))_(4)moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption spectroscopy.As a result,the as-synthesized Mn-O-C catalyst exhibits superior NitRR activity with an NH_(3)yield rate(RNH_(3))of 1476.9±62.6μg h^(−1)cm^(−2)at−0.7 V(vs.reversible hydrogen electrode,RHE)and a faradaic efficiency(FE)of 89.0±3.8%at−0.5 V(vs.RHE)under ambient conditions.Further,when evaluated with a practical flow cell,Mn-O-C shows a high RNH_(3)of 3706.7±552.0μg h^(−1)cm^(−2)at a current density of 100 mA cm−2,2.5 times of that in the H cell.The in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn-(O-C_(2))_(4)sites not only effectively inhibit the competitive hydrogen evolution reaction,but also greatly promote the adsorption and activation of nitrate(NO_(3)^(−)),thus boosting both the FE and selectivity of NH_(3)over Mn-(O-C_(2))_(4)sites.

关键词： Atomically dispersed Oxygen coordination Nitrate reduction reaction In situ spectroscopic studies Hydrogen evolution reaction

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Cation-πinteractions regulate electrocatalytic water oxidation over iridium single atoms supported on conjugated polymers

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Science China Chemistry 2024年第6期67卷 2063-2069页

作者： Jing Bai yunxia Liu Ziwei Ma Shouhan Zhang Guojie Chao Haiping Lin Elke Debroye Longsheng Zhang Tianxi Liu Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi214122China School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an710072China School of Physics and Information Technology Shanxi Normal UniversityXi’an710062China Department of Chemistry KU LeuvenCelestijnenlaan 200FLeuven3001Belgium

Designing cost-effective and high-performing metal catalysts is significant for many renewable energy conversion technologies.Lowering metal loading without sacrificing activity and durability is highly desired for the catalyst design,especially for those reactions where the noble metals deliver the best catalyzing performance.Single-atom catalysts(SACs)with maximal metalatom utilization,homogeneous and tailorable active sites have emerged as promising catalyst candidates,where the local coordination structures of the metal atoms in SACs largely determine the reaction kinetics.Previous design strategies of constructing strong metal-support interactions can stabilize the individual metal atoms in SACs,but present obstacles to provide a flexible manipulation platform for elaborately tailoring the coordination structures to achieve performance optimization towards a specifically targeted reaction.Here,for the proof-of-concept study,we report a novel design of SAC with iridium(Ir)single atoms supported on conjugated polymer,in which the adsorption energies of reaction intermediates on Ir atoms and the reaction kinetics towards acidic water oxidation can be readily optimized through modulating the formed cation-πinteractions that can be tailored by adjusting the molecular structures of conjugated polymers.This strategy establishes a general route to develop targeted SACs for various catalytic reactions.

关键词： conjugated polymers single-atom catalysts cation-πinteractions oxygen evolution reaction

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Facile synthesis of NiMn2S4 nanoflakes on nickel foam for high-performance aqueous asymmetric supercapacitors

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Science China(Technological Sciences) 2024年第2期67卷 499-508页

作者： ADIL Emin LI YaLi GAO Zhe DONG yunxia LI DongHao CHEN YongChao FU YuJun HE DeYan LI JunShuai LONGi Institute of Future Technology and School of Materials&EnergyLanzhou UniversityLanzhou 730000China

Supercapacitors display promising electrochemical performance with high power density and excellent cycle stability.However,their low energy density limits their advancement in a broader range of applications.To enhance their energy density,we proposed self-assembled spinel NiMn2S4nanoflakes grown on nickel foam which we successfully prepared by a facile hydrothermal method.The NiMn2S4electrode delivers a high capacitance of 2096.7 F g^(-1)at 1.0 A g^(-1),with an exceptional rate capability(~720.6 F g^(-1)at a very high current density of 100 A g^(-1))and good cycle stability(~85.1%retention of the initial capacitance after 7000 cycles with the Coulombic efficiency around 100%).The as-fabricated asymmetric supercapacitors based on NiMn2S4nanoflakes//active carbon demonstrate an energy density of 73.6 W h kg^(-1)at 800.5 W kg^(-1)and adequate cycling performance of~84.6%capacitance retention at 15 A g^(-1)after 10000 cycles.The results reveal that the nanostructured NiMn2S4is an excellent electrode material for high-performance energy storage applications.

关键词： NiMn2S4 nanostructure high capacitance aqueous supercapacitors long cycle stability high energy density

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IMAGGS: a radiogenomic framework for identifying multi-way associations in breast cancer subtypes

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Journal of Genetics and Genomics 2024年第4期51卷 443-453页

作者： Shuyu Liang Sicheng Xu Shichong Zhou Cai Chang Zhiming Shao Yuanyuan Wang Sheng Chen yunxia Huang Yi Guo Department of Electronic Engineering School of Information Science and TechnologyFudan UniversityShanghai 200433China The Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention(MICCAI)of Shanghai Shanghai 200032China Shanghai Key Laboratory of Metabolic Remodeling and Health Institute of Metabolism and Integrative BiologyFudan UniversityShanghai 200433China Department of Ultrasound Fudan University Shanghai Cancer CenterDepartment of OncologyShanghai Medical CollegeFudan UniversityShanghai 200032China Department of Breast Surgery Fudan University Shanghai Cancer CenterDepartment of OncologyShanghai Medical CollegeFudan UniversityShanghai 200032China

Investigating correlations between radiomic and genomic profiling in breast cancer(BC)molecular subtypes is crucial for understanding disease mechanisms and providing personalized treatment.We present a well-designed radiogenomic framework image–gene–gene set(IMAGGS),which detects multi-way associations in BC subtypes by integrating radiomic and genomic features.Our dataset consists of 721 patients,each of whom has 12 ultrasound(US)images captured from different angles and gene mutation data.To better characterize tumor traits,12 multi-angle US images are fused using two distinct strategies.Then,we analyze complex many-to-many associations between phenotypic and genotypic features using a machine learning algorithm,deviating from the prevalent one-to-one relationship pattern observed in previous studies.Key radiomic and genomic features are screened using these associations.In addition,gene set enrichment analysis is performed to investigate the joint effects of gene sets and delve deeper into the biological functions of BC subtypes.We further validate the feasibility of IMAGGS in a glioblastoma multiforme dataset to demonstrate the scalability of IMAGGS across different modalities and diseases.Taken together,IMAGGS provides a comprehensive characterization for diseases by associating imaging,genes,and gene sets,paving the way for biological interpretation of radiomics and development of targeted therapy.

关键词： IMAGGS Radiogenomic framework "lmage-gene-geneset"associations Molecular subtypes Breast cancer

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high-power laser;off-axis reflective exposure system;pulse compression grating;spatial frequency errors;specifications

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High Power Laser Science and Engineering 2024年第1期12卷 1-12页

作者： Chen Hu Songlin Wan Guochang Jiang Haojin Gu Yibin Zhang yunxia Jin Shijie Liu Chenqiang Zhao Hongchao Cao Chaoyang Wei Jianda Shao Precision Optical Manufacturing and Testing Center Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences(CAS)ShanghaiChina Key Laboratory for High Power Laser Material of Chinese Academy of Sciences Shanghai Institute of Optics and Fine MechanicsCASShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhouChina China-Russian Belt and Road Joint Laboratory on Laser Science ShanghaiChina

The large-aperture pulse compression grating(PCG) is a critical component in generating an ultra-high-intensity, ultra-short-pulse laser;however, the size of the PCG manufactured by transmission holographic exposure is limited to large-scale high-quality materials. The reflective method is a potential way for solving the size limitation, but there is still no successful precedent due to the lack of scientific specifications and advanced processing technology of exposure mirrors. In this paper, an analytical model is developed to clarify the specifications of components, and advanced processing technology is adopted to control the spatial frequency errors. Hereafter, we have successfully fabricated a multilayer dielectric grating of 200 mm × 150 mm by using an off-axis reflective exposure system with Φ300 mm. This demonstration proves that PCGs can be manufactured by using the reflection holographic exposure method and shows the potential for manufacturing the meter-level gratings used in 100 petawatt class high-power lasers.

关键词： high-power laser off-axis reflective exposure system pulse compression grating spatial frequency errors specifications

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以法治手段维护主流意识形态安全研究

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湖湘论坛 2024年第1期37卷 78-86页

作者：杨云霞西北工业大学马克思主义学院陕西西安710072

面对错误思潮对主流意识形态安全的冲击,法治是坚决同错误思潮作斗争的重要手段。一方面,全面依法治国基本方略的实施、司法实践中涉意识形态案件的不断出现、霸权国家在意识形态领域采取的所谓“法治”行为等决定了以法治维护意识形态... 详细信息

面对错误思潮对主流意识形态安全的冲击,法治是坚决同错误思潮作斗争的重要手段。一方面,全面依法治国基本方略的实施、司法实践中涉意识形态案件的不断出现、霸权国家在意识形态领域采取的所谓“法治”行为等决定了以法治维护意识形态安全具有必要性,以法律手段维护意识形态安全也是各个国家的通行做法。另一方面,在理论上法律自身的意识形态属性决定其具有保障主流意识形态安全的功能;在实践中社会主义核心价值观融入法治建设的重要实践探索、意识形态阵地建设和管理的法治化进程,决定了以法治手段维护意识形态安全具有可能性。当前我国主流意识形态安全立法在一些领域已经取得了进展,但仍面临诸多问题。在建设中国特色社会主义法治体系的进程中,既要完善意识形态安全相关立法,也要形成满足意识形态需求的司法政策、司法解释和指导性案例。

关键词：错误思潮主流意识形态安全法治政治文化

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Heterostructure Cu_(3)P-Ni_(2)P/CP catalyst assembled membrane electrode for high-efficiency electrocatalytic nitrate to ammonia

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Nano Research 2024年第6期17卷 4872-4881页

作者： Meng Jin Jiafang Liu Xian Zhang Shengbo Zhang Wenyi Li Dianding Sun yunxia Zhang Guozhong Wang Haimin Zhang Laboratory of Materials Physics Centre for Environmental and Energy NanomaterialsAnhui Key Laboratory of Nanomaterials and NanotechnologyCAS Center for Excellence in NanoscienceInstitute of Solid State PhysicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Anhui Contango New Energy Technology Co. Ltd.Hefei 230031China

Electrochemical nitrate reduction reaction(NO_(3)RR)is a promising means for generating the energy carrier ammonia.Herein,we report the synthesis of heterostructure copper-nickel phosphide electrocatalysts via a simple vapor-phase hydrothermal method.The resultant catalysts were evaluated for electrocatalytic nitrate reduction to ammonia(NH_(3))in three-type electrochemical reactors.In detail,the regulation mechanism of the heterogeneous Cu_(3)P-Ni_(2)P/CP-x for NO_(3)RR performance was systematically studied through the H-type cell,rotating disk electrode setup,and membrane-electrode-assemblies(MEA)electrolyzer.As a result,the Cu_(3)P-Ni_(2)P/CP-0.5 displays the practicability in an MEA system with an anion exchange membrane,affording the largest ammonia yield rate(RNH_(3))of 1.9 mmol·h^(−1)·cm^(−2),exceeding most of the electrocatalytic nitrate reduction electrocatalysts reported to date.The theoretical calculations and in-situ spectroscopy characterizations uncover that the formed heterointerface in Cu_(3)P-Ni_(2)P/CP is beneficial for promoting nitrate adsorption,activation,and conversion to ammonia through the successive hydrodeoxygenation pathway.

关键词： electrocatalytic nitrate reduction to ammonia three-type reactors membrane-electrode-assemblies system operando ATR-IRRAS successive hydrodeoxygenation pathway

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