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Hot deformation behavior and workability characteristic of a fine-grained Mg–8Sn–2Zn–2Al alloy with processing map

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Journal of Materials Science & Technology 2019年第6期35卷 1198-1209页

作者： Weili Cheng Yang Bai Shichao Ma Lifei Wang Hongxia Wang Hui Yu Shanxi key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Taiyuan University of Technology Taiyuan 030024China School of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China School of Materials Science and Engineering Hebei University of Technology Tianjin 300132 China

The hot deformation behavior of a fine-grained Mg–8 Sn–2 Zn–2 Al(TZA822, in wt%) alloy was investigated in the temperature range of 150–350°C and the strain rate of 0.01–10 s^-1 employing thermomechanical simulator. In most of the cases, the material showed typical dynamic recrystallization(DRX) features i.e., a signal peak value followed by a gradual decrease or to reach a steady state. The work hardening rate was found to increase with decreasing temperature and increasing strain rate, while strain rates had great effects on work hardening behavior. Meanwhile, the constitutive analysis indicated that cross-slip of dislocations was likely to be the dominant deformation mechanism. In addition, the processing map at the strain of 0.1–0.7 showed two stability domains with high power dissipation efficiencies and the optimum hot working parameters for the studied alloy was determined to be 350°C/0.01 s^-1 and 350°C/10 s^-1, at which continuous DRX(CDRX) and discontinuous DRX(DDRX) as main softening mechanism. The instability regions occurred at 200–250°C/10 s^-1 and the main flow instability mechanism was twinning and/or flow localization bands, which were prone to induce cracks and caused in-consistent mechanical properties of the alloy.

关键词： Mg-Sn based alloy Hot deformation Processing map Dynamic recrystallization

A method for extracting anomaly map of Au and As using combination of U-statistic and Euclidean distance methods in Susanvar district,Iran

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Journal of Central South University 2017年第11期24卷 2693-2704页

作者： Seyyed Saeed Ghannadpour Ardeshir Hezarkhani Mostafa Sharifzadeh Department of Mining & Metallurgical Engineering Amirkabir University of Technology (Tehran Polytechnic) Department of Mining Engineering and Metallurgical Engineering Western Australia School of MineCurtin University

Quantitative descriptions of geochemical patterns and providing geochemical anomaly map are important in applied geochemistry. Several statistical methodologies are presented in order to identify and separate geochemical anomalies. The U-statistic method is one of the most important structural methods and is a kind of weighted mean that surrounding points of samples are considered in U value determination. However, it is able to separate the different anomalies based on only one variable. The main aim of the presented study is development of this method in a multivariate mode. For this purpose, U-statistic method should be combined with a multivariate method which devotes a new value to each sample based on several variables. Therefore, at the first step, the optimum p is calculated in p-norm distance and then U-statistic method is applied on p-norm distance values of the samples because p-norm distance is calculated based on several variables. This method is a combination of efficient U-statistic method and p-norm distance and is used for the first time in this research. Results show that p-norm distance of p=2(Euclidean distance) in the case of a fact that Au and As can be considered optimized p-norm distance with the lowest error. The samples indicated by the combination of these methods as anomalous are more regular, less dispersed and more accurate than using just the U-statistic or other nonstructural methods such as Mahalanobis distance. Also it was observed that the combination results are closely associated with the defined Au ore indication within the studied area. Finally, univariate and bivariate geochemical anomaly maps are provided for Au and As, which have been respectively prepared using U-statistic and its combination with Euclidean distance method.

关键词： mineral anomaly Susanvar district U-statistic method Euclidean distance bivariate anomaly map

Defocus Hyperspectral Image Deblurring with Adaptive Reference Image and Scale map

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Journal of Computer Science & Technology 2019年第3期34卷 569-580页

作者： De-Wang Li Lin-Jing Lai Hua Huang School of Computer Science and Technology Beijing Institute of TechnologyBeijing 100081China

Defocus blur is one of the primary problems among hyperspectral imaging systems equipped with simple lenses. Most of the previous deblurring methods focus on how to utilize structure information of a single channel, while ignoring the characteristics of hyperspectral images. In this work, we analyze the correlations and differences among spectral channels, and propose a deblurring framework for defocus hyperspectral images. First, we divide the hyperspectral image channels into two sets, and the set with less blur is treated as a group of spectral bases. Then, according to the inherent correlations of spectral channels, a reference image can be derived from the spectral bases to guide the restoration of blurry channels. Finally, considering the disagreement between the reference image and the ground truth, a scale map based on gradient similarity is introduced as a prior in the deblurring framework. The experimental results on public dataset demonstrate that the proposed method outperforms several image deblurring methods in both visual effect and quality metrics.

关键词： hyperspectral image defocus blur deblurring reference image scale map

Methods of 3D map storage based on geo-referenced image database

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中国有色金属学会会刊：英文版 2011年第S3期21卷 654-658页

作者： YUAN Zhan-liang1, 2, LI Xun1, WANG Jin-ling1, YUAN Qi-qi1, XU Dan2, DIAO Jing-jing2 1. School of Surveying and Spatial Information Systems, University of New South Wales, NSW 2032, Australia 2. School of Surveying and mapping, Henan Polytechnic University, Jiaozuo 454000, China School of Surveying and Spatial Information Systems University of New South Wales NSW 2032 Australia School of Surveying and mapping Henan Polytechnic University Jiaozuo 454000 China

In order to store and manage a large amount of ground and indoor image data with high resolution, an integrated data management system needs to be developed. Possible strategies for this purpose were discussed together with initial test on the newly defined 3D maps. The features of such 3D maps, data organization, key techniques used for the map storage, such as image compression based on wavelet transformation, quadtree index, update and retrieval, were analyzed, with the goals of bringing some profits to the storage and management of the digital data in the visual construction of digital mine, digital city and digital community.

关键词： 3D map geo-referenced image image database storage technology

Data-Driven Microstructure and Microhardness Design in Additive Manufacturing Using a Self-Organizing map

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Engineering 2019年第4期5卷 730-735页

作者： Zhengtao Gan Hengyang Li Sarah J.Wolff Jennifer L.Bennett Gregory Hyatt Gregory J.Wagner Jian Cao Wing Kam Liu Department of Mechanical Engineering Northwestern UniversityEvanstonIL 60208USA DMG MORI Hoffman EstatesIL 60192USA

To design microstructure and microhardness in the additive manufacturing(AM)of nickel(Ni)-based superalloys,the present work develops a novel data-driven approach that combines physics-based models,experimental measurements,and a data-mining *** simulation is based on a computational thermal-fluid dynamics(CtFD)model,which can obtain thermal behavior,solidification parameters such as cooling rate,and the dilution of solidified *** on the computed thermal information,dendrite arm spacing and microhardness are estimated using well-tested mechanistic *** microstructure and microhardness are determined and compared with the simulated values for *** visualize process-structure-properties(PSPs)linkages,the simulation and experimental datasets are input to a data-mining model-a self-organizing map(SOM).The design windows of the process parameters under multiple objectives can be obtained from the visualized *** proposed approaches can be utilized in AM and other data-intensive ***-driven linkages between process,structure,and properties have the potential to benefit online process monitoring control in order to derive an ideal microstructure and mechanical properties.

关键词： Additive manufacturing Data science Multiphysics modeling Self-organizing map Microstructure Microhardness Ni-based superalloy

Solving for the Fixed Points of 3-Cycle in the Logistic map and Toward Realizing Chaos by the Theorems of Sharkovskii and Li–Yorke

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Communications in Theoretical Physics 2014年第10期61卷 485-496页

作者： M.Howard Lee Department of Physics and Astronomy University of GeorgiaAthensGA 30602USA Korea Institute for Advanced Study Seoul 130-012Korea

Sharkovskii proved that, for continuous maps on intervals, the existence of 3-cycle implies the existence of all others. Li and Yorke proved that 3-cycle implies chaos. To establish a domain of uncountable cycles in the logistic map and to understand chaos in it, the fixed points of 3-cycle are obtained analytically by solving a sextic equation. At one parametric value, a fixed-point spectrum, resulted from the Sharkovskii limit, helps to realize chaos in the sense of Li and Yorke.

关键词： logistic map chaos 3-cycle fixed points Sharkovskii theorem Li-Yorke theroem

Development of a model to generate a risk map in a building fire

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Science China(Technological Sciences) 2010年第10期53卷 2739-2747页

作者： CHU YanYan, ZHANG Hui, SHEN ShiFei, YANG Rui & QIAO LiFeng Center for Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China Center for Public Safety Research Department of Engineering Physics Tsinghua University Beijing China

Fire simulations and sensors are widely used in building fires,various data such as temperature,CO and CO2 concentration,visibility can be obtained by sensors and sensor-based simulation. It is important to generate a risk map based on such data so that we can use it to estimate safety of the building. In this paper,we propose a method to generate a dynamical,integrated risk map using sensor readings in a building fire. Such risk evaluation model is developed using similarity comparison between the space state and dangerous state by a likelihood distance calculating and data grouping from a two-step cluster method. The risk evaluation model considers the integrated influence on the occupants in the zone from high temperature,lack of oxygen,toxic and harmful gases and shows the relative fire risk map at certain time. Based on the simulation study,it is proved that multi-factor fire risk analysis would be more objective and accurate than single factor and two-factor risk analysis and the fire risk evaluation model can generate a risk map and provide the classification information and the whole building risk statistic results to support evacuation command and control.

关键词： building fire risk map cluster analysis fire simulation

Algorithm of symbol generation and configuration of land polygons in present land-use map

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中国有色金属学会会刊：英文版 2011年第S3期21卷 743-747页

作者： ZUO Xiao-qing, NIE Jun-tang Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 China

The symbolization of land polygon is an important part of cartography. In the mapping of traditional present land-use maps, the symbol of land polygons was usually filled by the method of filling or plotting, but these methods can't solve the spatial conflicts of the symbol. According to the principle of cartography, the rule of how to symbolize the land polygon was summarized, and a new method that can generate and deploy the land symbols was presented. By making use of C# programming language and Arc Engine developing components, the algorithm can generate land symbols presenting triangle and adjust the coordinate of the symbol. Through mapping the present land-use map of Honghe county, this algorithm can reduce 88.84% of the spatial conflicts error rate compared with the traditional methods. It improves the accuracy and efficiency of the map symbolic.

关键词： land symbol present land use map symbol configuration spatial conflict

A potential distribution map of wintering Swan Goose(Anser cygnoides)in the middle and lower Yangtze River floodplain,China

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Avian Research 2018年第4期9卷 344-353页

作者： An An Yong Zhang Lei Cao Qiang Jia Xin Wang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Co-Innovation Center for Sustainable Forestry in Southern China College of Biology and the EnvironmentNanjing Forestry UniversityNanjing 210037China School of Life Sciences University of Science and Technology of ChinaHefei 230026China

Background: Reliable information on the distribution of target species and influencing environmental factors is essential for effective conservation management. However, ecologists have often derived data from costly field surveys. The Swan Goose(Anser cygnoides), a vulnerable Anatidae species, winters almost exclusively in China's Yangtze River floodplain, but wintering numbers have been steadily decreasing. To better safeguard this unique species, modern modeling approaches can be used to quantify and predict its suitable wintering habitat. Specifically, a potential wintering distribution map of this species is critically ***: This study used the maximum entropy approach to model a distribution map of this species. In total, data from 97 up-to-date sites were extracted from 1263 survey sites(excluding duplicate data). After eliminating spatial autocorrelation, 11 environmental variables, including factors related to climate, land structure, vegetation, and anthropogenic activities, were used for model ***: The prediction distribution map shows that the population has concentrated mainly in the boundary area of Anhui, Hubei, and Jiangxi provinces, especially along the Yangtze River. Modeling results suggest that areas within the middle and lower Yangtze River floodplain, such as those in Hunan and Hubei provinces and the eastern coastal area of Zhejiang Province, demonstrate a potential level of "medium" suitability for this species to ***: Results from this study provide fundamental information for the restoration and management of the Swan Goose. Our "visualized" potential distribution map can assist in planning optimal conservation strategies, and consequently may help to increase the number of wintering populations in China.

关键词： Swan Goose Species distribution map Maxent Ecological conservation management