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Local chemical ordering enhances simultaneously strength and ductility of Ti-V-Zr-Nb-Al lightweight multi-component alloys

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JOURNAL OF MATERIALS research AND techNOLOGY-JMR&T 2025年 36卷 9289-9297页

作者： Yang, Hengyong Feng, Chuangshi Tang, Yu Xiao, Meng Zeng, Kai Guan, Zhou Song, Tao Yuan, Xin He, Zhicheng Zhang, Jiawei Yang, Chao Zhang, Fuxiang South China Univ Technol Natl Engn Res Ctr Near Net Shape Forming Met Mat Guangdong Prov Key Lab Proc & Forming Adv Met Mat Guangzhou 510640 Peoples R China Songshan Lake Mat Lab Dongguan 523808 Peoples R China

Refractory multi-component alloys display superior mechanical properties at elevated temperatures. However, their brittleness at ambient temperatures, combined with challenging processability, high density, and costeffectiveness, has hindered their widespread application in engineering. In this work, two types of Ti60(V2Zr3Nb2)40(A0) and Ti60(V2Zr3Nb2)34Al6(A6) multi-component alloys with a single Body-Centered Cubic (BCC) structure, were designed based on phase formation principles. These alloys were then manufactured using a combination of vacuum arc melting, cold rolling, and heat treatment processes. It is noteworthy that the A6 alloy present excellent processibility, achieving a 409 % elongation with a 90 % reduction in thickness, and its theoretical density decreased from 5.50 g/cm3 to 5.24 g/cm3 compared to the A0 alloy. Meanwhile, tensile tests revealed that the A6 alloy exhibited a simultaneous increase in yield strength and ductility by 10.3 % and 17.5 %, respectively, when compared to the A0 alloy. The enhanced mechanical properties were mainly attributed to the presence of Local Chemical Ordering (LCO), which was clearly observed in the undeformed sample via transmission electron microscope. Notably, the LCO was significantly influenced by deformation, and no obvious LCO was observed in the deformed alloy. The underline mechanism between LCO and dislocation was also explored. This work provides a strategy for developing novel lightweight refractory multi-component alloys with highstrength-ductility, good processibility and cost-effective.

关键词： Multi-component alloy Mechanical properties Deformation mechanism Processibility Local chemical ordering

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CdSe/CdS纳米晶在壳层形成和生长过程中的形貌调控:表面配体对晶体结构的决定性作用

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Science china Materials 2023年第9期66卷 3621-3628页

作者：郝俊杰刘皓宸段西健周子明赵冰心张文达徐冰孙小卫 Marie-Helene Delville Centre national de la recherche scientifique University of BordeauxBordeaux INPICMCBUMR 5026PessacF-33608France Institute of Nanoscience and Applications and Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China College of Integrated Circuits and Optoelectronic Chips Shenzhen Technology UniversityShenzhen 518118China Department of Materials Science and Engineering and Centre for Functional Photonics(CFP)City University of Hong KongHong Kong SAR 999077China Key Laboratory of Energy Conversion and Storage Technologies(Southern University of Science and Technology) Ministry of EducationShenzhen 518055China Shenzhen Planck Innovation Technologies Co. Ltd.Shenzhen 518173China Hainan Provincial Key Laboratory of Fine Chemicals Hainan UniversityHaikou 570228China

CdSe/CdS纳米晶是研究最多的半导体纳米晶之一,然而,仍有许多方面有待研究.本文中,我们揭示了核-壳纳米晶的形貌主要由表面配体和核心浓度控制,而非核心的晶体结构.其中,羧酸镉促进各向同性结构的生长,而相反地,长链膦酸镉有利于各向异... 详细信息

CdSe/CdS纳米晶是研究最多的半导体纳米晶之一,然而,仍有许多方面有待研究.本文中,我们揭示了核-壳纳米晶的形貌主要由表面配体和核心浓度控制,而非核心的晶体结构.其中,羧酸镉促进各向同性结构的生长,而相反地,长链膦酸镉有利于各向异性结构的制备.对于蝌蚪形貌纳米晶,羧酸镉对于头部壳层影响较大,而膦酸镉在各向异性尾部生长中起主要作用.与预期相反, CdSe核心的晶体结构(闪锌矿或纤锌矿)在决定最终的晶体形貌方面几乎没有作用,这可能是由于CdS壳层两个阶段的生长,并导致了蝌蚪形貌的生成.通过选择恰当的表面配体,可以在CdSe/CdS核壳结构形成和生长过程中精确地调控其形貌.在本工作中,蝌蚪、纳米花、点-棒结构、多足结构均可以通过调控表面配体的比率而获得.这种独特的晶体生长机制可以应用于其他基于种子生长的工艺以构筑各向异性纳米结构.

关键词：半导体纳米晶纳米花晶体结构形貌调控晶体形貌各向异性壳层浓度控制

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A highly orientational architecture formed by covalently bonded graphene to achieve high through-plane thermal conductivity of polymer composites

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NANOSCALE 2022年第31期14卷 11171-11178页

作者： Yan, Qingwei Gao, Jingyao Chen, Ding Tao, Peidi Chen, Lu Ying, Junfeng Tan, Xue Lv, Le Dai, Wen Alam, Fakhr E. Yu, Jinhong Wang, Yuezhong Li, He Xue, Chen Nishimura, Kazuhito Wu, Sudong Jiang, Nan Lin, Cheng-Te Chinese Acad Sci Qianwan Inst Ningbo Inst Mat Technol & Engn NIMTE Ningbo 315201 Peoples R China Chinese Acad Sci Ningbo Inst Mat Technol & Engn NIMTE Zhejiang Key Lab Marine Mat & Protect Technol Key Lab Marine Mat & Related Technol Ningbo 315201 Peoples R China Univ Chinese Acad Sci Ctr Mat Sci & Optoelect Engn Beijing 100049 Peoples R China Jiangxi Copper Technol Res Inst Co Ltd Nanchang Jiangxi Peoples R China Hunan Univ Coll Mech & Vehicle Engn State Key Lab Adv Design & Mfg Vehicle Body Changsha Peoples R China Univ Technol & Appl Sci Appl Sci Sect Dept Engn Nizwa Oman Kogakuin Univ Mech Syst Engn Adv Nanoproc Engn Lab Tokyo 1920015 Japan Southern Univ Sci & Technol Acad Adv Interdisciplinary Studies Shenzhen 518055 Peoples R China Southern Univ Sci & Technol Guangdong Hong Kong Macao Joint Lab Photon Therma Shenzhen 518055 Peoples R China

Combining the advantages of high thermal conductivities and low graphene contents to fabricate polymer composites for applications in thermal management is still a great challenge due to the high defect degree of exfoliated graphene, the poor orientation of graphene in polymer matrices, and the horrible phonon scattering between graphene/graphene and graphene/polymer interfaces. Herein, mesoplasma chemical vapor deposition (CVD) technology was successfully employed to synthesize vertically aligned graphene nanowalls (GNWs), which are covalently bonded by high-quality CVD graphene nanosheets. The unique architecture leads to an excellent thermal enhancement capacity of the GNWs, and a corresponding composite film with a matrix of polyvinylidene fluoride (PVDF) presented a high through-plane thermal conductivity of 12.8 +/- 0.77 W m(-1) K-1 at a low filler content of 4.0 wt%, resulting in a thermal conductivity enhancement per 1 wt% graphene loading of 1659, which is far superior to that using conventional graphene structures as thermally conductive pathways. In addition, this composite exhibited an excellent capability in cooling a high-power light-emitting diode (LED) device under real application conditions. Our finding provides a new route to prepare high-performance thermal management materials with low filler loadings via the rational design of the microstructures/interfaces of graphene skeletons.

关键词： Graphene

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Scalable non-invasive imaging through dynamic scattering media at low photon flux

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OPTICS AND LASERS IN ENGINEERING 2021年 144卷

作者： Sun, Yiwei Wu, Xiaoyan Zheng, Yuanyi Fan, Jianping Zeng, Guihua Shanghai Jiao Tong Univ Ctr Quantum Sensing & Informat Proc State Key Lab Adv Opt Commun Syst & Networks Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Affiliated Peoples Hosp 6 Dept Ultrasound Shanghai 200233 Peoples R China Univ North Charlotte Dept Comp Sci Charlotte NC 28223 USA

When the intensity of light reduces to single-photon level, the shot noise becomes dominant. Random scatter, especially the time-varying media will highly increase the photon-limited imaging challenge that the traditional imaging means are inadequate to cope with. In this paper, we develop a new scalable "one to all" imaging approach which focuses on dynamic scattering imaging under photon-limited condition. When the dynamic media optical density is five, we apply this principle to inverse scattering problem and retrieve high-quality images in a real-time way using as little as similar to 0.4 valid detected photons per pixel on average successfully. The effects of lighting intensities and perturbations are analyzed to highlight special significance of the work. The ultimate results demonstrate that one trained strategy is robust to a wide range of statistical variations in dynamic media, which outperforms common "one to one" method and improves the practical utility efficaciously. This non-invasive imaging work promises a wide prospect in photon-limited scattering applications such as in vivo bioimaging and so on.

关键词： Non-invasive imaging Dynamic scattering media Perturbation Photon-limited Deep learning

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Data mining: A novel strategy for production forecast in tight hydrocarbon resource in Canada by random forest analysis

Data mining: A novel strategy for production forecast in tig...

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International Petroleum technology Conference 2020, IPTC 2020

作者： Liao, Lulu Zeng, Yijin Liang, Yu Zhang, Hongbao Sinopec Research Institute of Petroleum Engineering China University of Texas at Austin United States

ISBN: (纸本)9781613996751

Unconventional hydrocarbon resources, including shale hydrocarbon, tight hydrocarbon and coalbed methane, have become an increasingly essential part of global oil and gas supply during the past decades. Tight Oil and Gas projects, especially in Canada, exhibit a number of unique features, such as large onshore geographical area, variable but relative low productivity, intensive drilling and formation stimulation programs and complicated operational process. These features differentiate such unconventional formations from conventional formations, thus the traditional knowledge and methodology cannot be simply applied to unconventional resource plays. To better develop a tight hydrocarbon formation with lower capital, expense and lifting cost, in this paper a novel model based on data mining for tight oil production prediction and Geography / Petrophysics / Engineering parameters optimization has been introduced. It establishes a correlation between Estimated Ultimate Recovery (EUR) and key independent parameters (geography / petrophysics / engineering) by machine learning analysis. In this study, all the data with more than 50 variables over Canada Cardium tight oil formation, including production, well logging, well testing, seismic, lab experiments and other tests, have been collected and used for the analysis. Firstly, the multi-sets of cumulative production data and relavent Geography / Petrophysics / Engineering (GPE) parameters are collected. Then a sensitivity test is carried out to determine the most important GPE parameters and thus a spatial database is set up. Based on the sensitive test and data mining results, multiple key parameters have been recognized and used as independent variables for the machine learning analysis. Among all the machine-learning algorithms, the Random Forest is applied to evaluate the relationship between EUR and multi independent variables. In order to improve the model accuracy, a supervised learning algorithm is applied to trai

关键词： Decision trees

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Vorwort

Sensoren und Messsysteme - 21. ITG/GMA-Fachtagung

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Sensoren und Messsysteme - 21. ITG/GMA-Fachtagung 2022年 3-3页

作者： Reindl, L. Wöllenstein, J. Universität Freiburg Germany Fraunhofer IPM Germany

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An evolutionary distributed framework for projection pursuit 24

An evolutionary distributed framework for projection pursuit

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24th KES International Conference on Knowledge-Based and Intelligent Information and Engineering Systems, KES 2020

作者： Ungureanu, Robert-Mihail Breaban, Mihaela Elena Faculty of Computer Science Alexandru Ioan Cuza University of Iasi Romania Bitdefender Iasi Romania

Projection Pursuit is a methodology for deriving meaningful low-dimensional representations of data. It generally aims at extracting features as linear combinations of the original attributes, under an algorithm which optimizes a function that quantifies the interestingness of the projection. The current paper builds on our previous research, extending an algorithmic framework based on evolutionary algorithms in two directions: At its roots a one-dimensional PP framework, we enhance it with two-dimensional search capabilities providing meaningful planar views (rotations) of the data;moreover, we provide a distributed implementation under Apache Spark. The distributed implementation is not meant only to deal with large data, but also to exploit the inherent parallelism of the evolutionary paradigm, enhancing the efficiency of the method not only when run on a cluster, but also on a single machine, exploiting the existing virtual CPUs. Several case studies illustrate the applicability of our framework and demonstrate its efficiency. © 2020 The Authors. Published by Elsevier B.V.

关键词： Genetic algorithms

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Improving Estimation of Forest Canopy Cover by Introducing Loss Ratio of Laser Pulses Using Airborne LiDAR

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMotE SENSING 2020年第1期58卷 567-585页

作者： Liu, Qingwang Fu, Liyong Wang, Guangxing Li, Shiming Li, Zengyuan Chen, Erxue Pang, Yong Hu, Kailong Chinese Acad Forestry Res Inst Forest Resource Informat Tech Beijing 100091 Peoples R China Southern Illinois Univ Dept Geog & Environm Resources Carbondale IL 62901 USA Chinese Acad Forestry Res Inst Forest Resource Informat Tech Beijing 100091 Peoples R China Southern Illinois Univ Dept Geog & Environm Resources Carbondale IL 62901 USA Cent South Univ Forestry & Technol Key Lab Forestry Remote Sensing Based Big Data & Changsha 410004 Peoples R China Natl Disaster Reduct Ctr Minist Emergency Management Peoples Republ China Beijing 100124 Peoples R China

Forest canopy cover (CC) directly and indirectly influences various processes of forest ecosystems. Airborne light detection and ranging (LiDAR) can be used to characterize forest spatial structures and further obtain estimates of forest CC. However, nonreturn laser pulses from targets of interest impact the estimation accuracy of forest CC. The objective of this article was to develop a novel method of estimating the nonreturn laser pulses to improve the estimation accuracy of forest CC using LiDAR data. The improved models for estimating forest CC were developed by introducing the loss ratio of laser pulses and a CC coefficient into the original models. The forest CC reference data were collected and used to validate the forest CC estimates. The results show that the loss ratio for forested areas was much higher than that for open ground areas. The range between the sensor and a target was a crucial factor that caused the loss of returns. The relationship between the range and the loss ratio was nonlinear in both open ground and forested areas. Compared with the original models, the improved models combining the loss ratio and the CC coefficient statistically significantly increased the estimation accuracy of the forest CC. Moreover, the forest CC estimates from the canopy height model (CHM) were more accurate than those from the height normalized point cloud (NPC) data. In addition, the simplified models were more generalized than the other models. This article is novel and has great potential to improve mapping of forest CC.

关键词： Forestry Laser radar Estimation Biological system modeling Three-dimensional displays Vegetation Lasers Canopy cover (CC) coefficient canopy height model (CHM) height normalized point cloud (NPC) loss ratio of laser pulses

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Dominant role of nitrogen stoichiometric flexibility in ecosystem carbon storage under elevated CO2

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SCIENCE OF THE TotAL ENVIRONMENT 2020年 747卷 141308页

作者： Zou, Junliang Li, Qianyu Osborne, Bruce Luo, Yiqi Beijing Acad Agr & Forestry Sci Beijing Res & Dev Ctr Grass & Environm Beijing 100097 Peoples R China Tsinghua Univ Minist Educ Key Lab Earth Syst Modeling Dept Earth Syst Sci Beijing 100084 Peoples R China Univ Coll Dublin UCD Sch Biol & Environm Sci Dublin 4 Ireland Univ Coll Dublin UCD Earth Inst Dublin 4 Ireland No Arizona Univ Dept Biol Sci Ctr Ecosyst Sci & Soc Box 5640 Flagstaff AZ 86011 USA

Interactions between the carbon (C) and nitrogen (N) cycles can impact on the sensitivity of terrestrial C storage to elevated atmospheric carbon dioxide (CO2) concentrations (eCO(2)). However, the underlying mechanisms associated with C-N interactions that influence terrestrial ecosystemC sequestration (C-seq) remains unclear. Here, we quantitatively analyzed published C and N responses to experimentally eCO(2) using a meta-analysis approach. We determined the relative importance of three principal mechanisms (changes in the total ecosystem N amount, redistribution of N between plant and soil pools, and flexibility of the C:N ratio) that contribute to increases in ecosystem C storage in response to eCO(2). Our results showed that eCO(2) increased C and N accumulation, resulted in higher C:N ratios in plant, litter, and soil pools and induced a net shift of N from soils to vegetation. These three mechanisms largely explained the increment of ecosystem Cseq under eCO(2), although the relative contributions differed across ecosystem types, with changes in the C:N ratio contributing 50% of the increment in forests C-seq, while the total N change contributed 60% of the increment in grassland C-seq. In terms of temporal variation in the relative importance of each of these three mechanisms to ecosystem C-seq: changes in the C:N ratio was the most important mechanismduring the early years (similar to 5 years) of eCO(2) treatment, whilst the contribution to ecosystem C-seq byN redistribution remained rather small, and the contribution by total N change did not show a clear temporal pattern. This study highlights the differential contributions of the three mechanisms to C-seq, which may offer important implications for future predictions of the C cycle in terrestrial ecosystems subjected to global change. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Carbon sequestration Global change Meta-analysis Nitrogen Stoichiometry C-N interaction

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Cellular automaton model considering the effect of brake light and traffic light at the intersection

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2022年第12期35卷

作者： Chen, Yu-Feng Dong, Zhang Che, Kai Xiang, Zheng-Tao Hubei Univ Automot Technol Sch Elect & Informat Engn Shiyan Hubei Peoples R China

Traffic flow modeling of urban traffic on a single-lane road with one traffic light operating as a bottleneck is the basis of research on urban road network. By introducing the brake light rules into ChSch model, we proposed a new cellular automaton traffic flow model of intersection considering the effect of brake light and traffic light to avoid running a red light and rear-end collision. The first vehicle of the vehicle queue formed in front of the stop line at red light (FVoQ) is focused, and the evolution characteristics of intersection traffic flow are analyzed. Results show that the proposed model is more realistic than ChSch model in the following aspects: (a) The FVoQ decelerates more smoothly with the proposed model. The behavior of smooth deceleration reflects the driver's desire of comfortable driving in real traffic. (b) The proportion of the FVoQ's great and sudden deceleration to avoid running a red light is greatly reduced with the proposed model. In ChSch model, the proportion is larger than 80%, while in the proposed model, the proportion is less than 1%. The behavior of great and sudden deceleration reflects the aggressive driving pattern of a few drivers in real traffic. (c) The rear-end collision accident rate caused by FVoQ's aggressive driving behaviors is greatly reduced with the proposed model, which conforms more to the real traffic.

关键词： cellular automaton model ChSch model traffic accident traffic flow

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