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Effect of heat treatment on microstructure and mechanical properties of a novel Al-Zn-Mg-Cu alloy

China Foundry 2025年

作者： Yan-mei Yang Xin-chen Tang Ye-fei Li Xue-wei Fang da-wei yi Zhi-yun Zhang Qiao-ling Zheng Zhi-xi Wang Guo-yu Zhang Su Zhang Hao Cheng Yang He yi-bo Liu Zi-han Wu Ya-nan Chen yi-min Gao State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an Aerospace Precision Electromechanical Institute

Effects of solution and aging treatment on the microstructure and mechanical properties of a novel Al-Zn-Mg-Cu alloy by microalloying rare elements Sc and Er were studied. The results show that solution time has a visible influence on the microstructure and mechanical properties of the alloy. Specifically, as the solution time increases, the area fraction of the residual phase in the alloy decreases, and the shape of the grain becomes more spheroidal and coarser, leading to a decrease in hardness. This is attributed to the dissolution of strengthening phases during the solution treatment, which weakens the solid solution strengthening *** single-stage aging treatment shows an initial increase in strength and hardness of the alloy, followed by a decrease as the aging time is extended, until a steady state is achieved. The optimal single-aging conditions are found to be at 120 ℃ for 24 h, where the alloy exhibits an excellent combination of high strength and good ductility, with an ultimate tensile strength(UTS) of 523 MPa, yield strength(YS) of 482 MPa, and elongation(El)of 1.75%, respectively. Compared to single-stage aging, double-stage aging(120 ℃ for 24 h and then 150 ℃ for 52 h) significantly increases the elongation of the alloy(4.17%), but the UTS reduces to 465.29 MPa, and YS reduces to 410.64 MPa. Transmission electron microscopy(TEM) observations disclose that the grain size, the distribution spacing of precipitates along the grain boundary, and the width of the precipitation-free zone(PFZ) all undergo augmentation as the duration of the second stage aging process elongates.

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Rotordynamic prediction of mode order transition when rotor has an overhang

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航空动力学报 2015年第2期30卷 397-409页

作者： Konstantin Shaposhnikov HONG Jie ZHANG da-yi MA Yan-hong School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

Nowadays rotating machinery grows and develops extremely fast due to its multi-branch *** the fields of rotordynamics and rotor balancing had a strong background based on previous experience in order to perform efficient and safe operation for the rotating machines,still there are problems which are hard to be dealt with in some special *** of them is balancing of the rotor with huge *** with overhang is inherent to have console modes,which previously often were observed separately from the other modes in rotordynamic *** such a way console modes,their behavior,order of appearance and interaction with other modes were described in current paper in more *** results confirmed that console modes obey the principle of orthogonality in the same way as all other modes and hence could be efficiently balanced using modal balancing *** results revealed likelihood of such phenomena as modes order transition,when the rotor has an *** a consequence perfectly balanced console rotor could not be so due to modes order transition effect when the bearing stiffness in situ differs from bearing stiffness of balancing *** results will be useful for engineers who are involved in area of rotating machinery vibration tuning for the rotor with huge overhang and benefit them to recognize these modes efficiently and to perform balancing successfully.

关键词：疲劳寿命分散性顺序统计量寿命分散系数小子样

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Efficient coupling of evanescent waves in rectangular waveguides based on ultrathin planar capacitive metasurfaces

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Science China(Information Sciences) 2021年第8期64卷 182-194页

作者： da yi Ming-Chun TANG Mei LI Xing-Chang WEI College of Microelectronics and Communication Engineering Chongqing University Zhejiang Provincial Key Laboratory of Advanced Microelectronic Intelligent Systems and Applications College of Information Science and Electronic Engineering Zhejiang University

This work proposes an approach to enable efficient coupling of evanescent waves below the cutoff frequency of a standard rectangular waveguide(RWG) system based on ultrathin planar capacitive metasurfaces(CMSs). It is demonstrated that the CMS at the RWG’s cross-section can couple the evanescent wave from one port to the other, and thus enable an efficient frequency-selective transmission below the cutoff frequency. Theoretical formulas, together with the equivalent circuit, are presented to quantitatively illustrate the operational mechanism of the proposed approach. The performance characteristics, including out-of-band suppression, Q-factor, transmission loss, and coupling bandwidth, are studied in a comprehensive manner. Three CMS samples with different surface impedance values are designed, fabricated, and *** measurement results show good agreement with the numerical values, validating their highly efficient evanescent wave coupling performance characteristic at selected frequencies below the cutoff frequency, with approximately 100% transmission efficiency. Benefiting from the admirable low-frequency coupling performance,this approach has potential applications in many miniaturized and high-performance transmission components, such as compact evanescent wave resonators, filters, and antennas.

关键词： cutoff frequency capacitive metasurface evanescent wave miniaturized components rectangular waveguide

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Variations and future projections of glacial discharge of Urumqi River Headwaters,eastern Tien Shan(1980s-2017)

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Advances in Climate Change Research 2024年第3期15卷 537-546页

作者： Hui ZHANG Fei-Teng WANG Ping ZHOU yi-da XIE State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

To address data scarcity on long-term glacial discharge and inadequacies in simulating and predicting hydrological processes in the Tien Shan,this study analysed the observed discharge at multiple timescales over 1980se2017 and projected changes within a representative glacierized high-mountain region:eastern Tien Shan,Central *** processes were simulated to predict changes under four future scenarios(SSP1,SSP2,SSP3,and SSP5)using a classical hydrological model coupled with a glacier dynamics *** rates at annual,monthly(June,July,August)and daily timescales were obtained from two hydrological gauges:Urumqi Glacier No.1 hydrological station(UGH)and Zongkong station(ZK).Overall,annual and summer discharge increased significantly(p<0.05)at both stations over the study *** intra-annual variations mainly resulted from differences in their recharge *** simulations show that a tipping point in annual discharge at UGH may occur between 2018 and 2024 under the four SSPs *** discharge is predicted to cease earlier at ZK than at *** relates to glacier type and size,suggesting basins with heavily developed small glaciers will reach peak discharge sooner,resulting in an earlier freshwater supply *** findings serve as a reference for research into glacial runoff in Central Asia and provide a decision-making basis for planning local water-resource projects.

关键词： Observed glacial discharge Temporal variations Urumqi River Headwaters Eastern Tien Shan Simulation and projection

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基于双驱双导模式的研究生环境污染治理课程教学改革与实践

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造纸技术与应用 2025年第1期53卷 51-55页

作者：刘云庆杨年炜钱大益伊犁师范大学资源与环境学院污染物化学与环境治理重点实验室新疆伊宁835000

随着我国经济社会的快速发展,环境污染问题日益凸显,对研究生环境污染治理课程的教学提出了更高的要求。传统的教学模式已经难以满足当前环境治理人才的培养需求。为此,文章提出了一种基于双驱双导模式的研究生环境污染治理课程教学改... 详细信息

随着我国经济社会的快速发展,环境污染问题日益凸显,对研究生环境污染治理课程的教学提出了更高的要求。传统的教学模式已经难以满足当前环境治理人才的培养需求。为此,文章提出了一种基于双驱双导模式的研究生环境污染治理课程教学改革方案,并在实际教学中进行了实践探索。双驱双导模式是一种旨在提高研究生教育质量和培养创新人才的教学改革模式。在环境污染治理课程的教育教学改革中,这种模式强调两个驱动(即理论与实践的结合)和两个指导(即导师和行业专家的共同指导),以培养学生的综合素质,提高学生的实践能力和创新思维,同时提高研究生解决实际问题的能力。

关键词：环境污染治理教学改革双驱双导模式研究生教育实践能力

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Role of activin receptor-like kinase 1 in vascular development and cerebrovascular diseases

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Neural Regeneration Research 2020年第10期15卷 1807-1813页

作者： Jun-Mou Hong yi-da Hu Xiao-Qing Chai Chao-Liang Tang Department of Vascular Surgery Zhongshan HospitalXiamen UniversityXiamenFujian ProvinceChina Department of Anesthesiology Renmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina Department of Anesthesiology The First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina

Activin receptor-like kinase 1(ALK1)is a transmembrane serine/threonine receptor kinase of the transforming growth factor beta(TGFβ)receptor ***1 is specifically expressed in vascular endothelial cells,and its dynamic changes are closely related to the proliferation of endothelial cells,the recruitment of pericytes to blood vessels,and functional differentiation during embryonic vascular *** pathophysiology of many cerebrovascular diseases is today understood as a disorder of endothelial cell function and an imbalance in the proportion of vascular ***,mutations in ALK1 and its co-receptor endoglin are major genetic risk factors for vascular arteriovenous *** studies have shown that ALK1 is closely related to the development of cerebral aneurysms,arteriovenous malformations,and cerebral *** this review,we describe the various roles of ALK1 in the regulation of angiogenesis and in the maintenance of cerebral vascular homeostasis,and we discuss its relationship to functional dysregulation in cerebrovascular *** review should provide new perspectives for basic research on cerebrovascular diseases and offer more effective targets and strategies for clinical diagnosis,treatment,and prevention.

关键词： activin receptor-like kinase 1 aneurysm atherosclerotic plaque endoglin extracellular matrix protein intracranial arteriovenous malformation matrix metalloproteinase pericyte transforming growth factor beta 1 pathway vascular development

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LLMs in medicine:The need for advanced evaluation systems for disruptive technologies

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The Innovation 2024年第3期5卷 1-2页

作者： yi-da Tang Er-dan Dong Wen Gao Department of Cardiology and Institute of Vascular Medicine Peking University Third HospitalBeijing 100191China State Key Laboratory of Vascular Homeostasis and Remodeling Peking UniversityBeijing 100191China University of Health and Rehabilitation Sciences Qingdao 266000China Peking University Beijing 100871China

In an era of rapid advancements in artificial intelligence(AI),the potential role of large language models(LLMs)in the medical field is receiving increasing *** progression of this technology not only highlights upcoming revolutionary changes in medical services but also offers unprecedented opportunities for the health care sector.1 LLMs’formidable capability to process natural language opens vast prospects for application in the medical field,including in the contexts of emergency triage,geriatric care,and digital medical workflows.

关键词： dis highlights services

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Indicator of climate variability:low treeline displacement in arid valleys of mountain areas,China

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Journal of Mountain Science 2023年第11期20卷 3250-3265页

作者： YAN Wei-po WANG Qing GUO Ya-lin HU Qi YANG Min AN yi-da School of Environment and Resource Southwest University of Science and TechnologyMianyang 621010China Sichuan Academy of Environmental Policy and Planning Chengdu 610041China

As climate change intensifies,finding an ecological indicator to quickly and accurately reflect the impact on mountain ecosystems is *** low treeline/timberline,highly sensitive to climate variability and changes significantly within 5–10years,provides a new way to study the response to regional climate *** study explored the distribution and vertical displacement patterns of the low treeline in the Upper Minjiang River of China,using SPOT remote sensing images in 1999 and 2013and long-term positional *** the Geodetector model,the study investigated the dominant climatic factors influencing the low treeline *** results showed that the low treeline was located at 1700–3200 m elevation on sunny slopes(southeast,south,southwest,and west slopes)with slopes over 25°.From 1999 to 2013,the low treeline moved downward by 6 m from 2561±264m to 2555±265 m,along with a warm–humid climate *** downward displacement was greater on slopes over 25°and shady slopes(-20 m and-10 m,respectively)than on slopes≤25°and sunny ***,the downward was greater in the warm and humid Zagunao River Basin(-15 m)compared to the arid valley center(-7 m)and the cold Heishui River Basin(-3 m).Meanwhile,the low treeline displacement correlated negatively with precipitation and relative humidity variations at the significance level of 0.05,with correlation coefficients of-0.572and-0.551,*** in relative humidity and temperature significantly affected the spatial differentiation of low treeline displacement with influencing power of 0.246(p=0.036<0.05)and 0.183(p=0.032<0.05),***,the low treeline is a moisture-limited line,and its formation and variation are closely related to regional water–heat *** study clarifies the indicative value of the low treeline for climate variability in mountain areas and can provide references for ecological restoration in arid valleys.

关键词： Low treeline Moisture-limited line Climate variability Remote sensing interpretation Geo-detector Arid valley

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A perceptual quality metric for 3D triangle meshes based on spatial pooling

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Frontiers of Computer Science 2018年第4期12卷 798-812页

作者： Xiang FENG Wanggen WAN Richard yi da XU Haoyu CHEN Pengfei LI J. Alfredo SANCHEZ School of Communication and Information Engineering Shanghai University Shanghai 200444 China Faculty of Engineering and Information Technology University of Technology Sydney Sydney NSW 2007 Australia Institute of Smart City Shanghai University Shanghai 200444 China Department of Computing Electronics and Mechatronics Universidad de las Americas Puebla (UDLAP) Cholula 72820 Mexico

In computer graphics, various processing operations are applied to 3D triangle meshes and these processes often involve distortions, which affect the visual quality of surface geometry. In this context, perceptual quality assessment of 3D triangle meshes has become a crucial issue. In this paper, we propose a new objective quality metric for assessing the visual difference between a reference mesh and a corresponding distorted mesh. Our analysis indicates that the overall quality of a distorted mesh is sensitive to the distortion distribution. The proposed metric is based on a spatial pooling strategy and statistical descriptors of the dis- tortion distribution. We generate a perceptual distortion map for vertices in the reference mesh while taking into account the visual masking effect of the human visual system. The proposed metric extracts statistical descriptors from the dis- tortion map as the feature vector to represent the overall mesh quality. With the feature vector as input, we adopt a support vector regression model to predict the mesh quality score. We validate the performance of our method with three publicly available databases, and the comparison with state-of-the-art metrics demonstrates the superiority of our method. Experimental results show that our proposed method achieves a high correlation between objective assessment and subjective scores.

关键词： mesh visual quality assessment spatial pooling statistical descriptors support vector regression visual masking

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Radiological monitoring results of the ambient environment around Qinshan Nuclear Power Plant

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Nuclear Science and Techniques 2004年第1期15卷 59-64页

作者： ZHANGRong-Suo ZENGGuang-Jian JIANGRang-Rong YEJi-da XIANGYuan-yi HUANGRen-Jie CAOZhong-Gang ZhejiangProvinceEnvironmentalRadiationMonitoringCenter Hangzhou310012

A plan of surveillance monitoring Qinshan Nuclear Power Plant (QNPP) has been implemented since 1992, the objective of which is to establish the database of environmental radiation information around QNPP, and to detect any unplanned discharge of radioactive materials from QNPP. This paper presents the monitoring results for radionuclide concentrations in the environmental matrices before and after QNPP operation. The radionuclide con- centrations in vegetation, food, atmosphere, soil and littoral soil samples have been determined. After operation of QNPP, the mean values of 137Cs, Sr and H in water are 0.6, 4.9 mBq/L and 1.7 Bq/L, respectively; the mean values 90 3 of137Cs in soil and littoral soil are 3.5 and 2.7 Bq/kg, respectively; the mean values of137Cs in rice, green cabbage, meat, mullet, milk and tea are 0.033, 0.039, 0.081, 0.069, 0.018 and 0.62 Bq/kg, respectively; the mean values of 90 Sr in rice, green cabbage and tea are 0.081, 0.315 and 4.1 Bq/kg, respectively; gross β activity in fallout is 0.9 Bq·m-2·d-1. Compared with the data before QNPP’s operation, no significant difference has heen observed in the radioactivity of137Cs, Sr, H and the gross β activity in ambient environmental matrices from 1992 to 2001, and 90 3 there are only some fluctuations within the range of background.

关键词：辐射监测秦山核电站 QNPP 环境污染辐射防护

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