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Feature-reduction and semi-simulated data in functional connectivity-based cortical parcellation

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Neuroscience Bulletin 2013年第3期29卷 333-347页

作者： Xiaoguang tian Cirong liu tianzi Jiang Joshua Rizak Yuanye Ma Xintian Hu Kunming Institute of Zoology Chinese Academy of Sciences The University of Queensland Queensland Brain Institute LIAMA Center for Computational Medicine National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Yunnan Key Lab of Primate Biomedical Research State Key Laboratory of Brain and Cognitive Science Institute of Biophysics Chinese Academy of Sciences Kunming Bio-International

Recently, restingstate functional magnetic resonance imaging has been used to parcellate the brain into functionally distinct regions based on the information available in functional connectivity maps. However, brain voxels are not independent units and adjacent voxels are always highly correlated, so functional connectivity maps contain redundant information, which not only impairs the computational efficiency during clustering, but also reduces the accuracy of clustering results. The aim of this study was to propose featurereduction approaches to reduce the redundancy and to develop semisimulated data with defined ground truth to evaluate these approaches. We proposed a featurereduction approach based on the Affinity Propagation Algorithm （APA） and compared it with the classic feature reduction approach based on Principal Component Analysis （PCA）. We tested the two approaches to the parcellation of both semisimulated and real seed regions using the Kmeans algorithm and designed two experiments to evaluate their noise resistance. We found that all functional connectivitymaps （with/without feature reduction） provided correct information for the parcellation of the semi simulated seed region and the computational efficiency was greatly improved by both feature reduction approaches. Meanwhile, the APAbased featurereduction approach outperformed the PCA based approach in noiseresistance. The results suggested that functional connectivity maps can provide correct information for cortical parcellation, and featurereduction does not significantly change the information. Considering the improvement in computational efficiency and the noiseresistance, featurereduction of functional connectivity maps before cortical parcellation is both feasible and necessary.

关键词： cortical parcellation resting-state fMRI functional connectivity feature reduction stimulateddata AP algorithm

Evaluation of Mechanical Properties of Cross-Laminated Timber with Different Lay-ups Using Japanese Larch

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Journal of Renewable Materials 2019年第10期7卷 941-956页

作者： Yingchun Gong Fenglu liu Zhaopeng tian Guofang Wu Haiqing Ren Cheng Guan Research Institute of Forestry New Technology Chinese Academy of ForestryBeijing100091China School of Technology Beijing Forestry UniversityBeijing10083China

Japanese larch is one of the main plantation tree species in China.A lack of engineered wood products made by Japanese larch,however,limits its application in wood *** this study,based on optimum process parameters,such as pressure(12 MPa),adhesive spread rate(200 g/m^(2))and adhesive(one-component polyurethane),the mechanical properties of Japanese larch-made cross-laminated timber(CLT)with different lay-ups were evaluated by means of the static *** of this study showed that variations in lay-ups significantly affected the mechanical properties of *** strength and modulus of bending and parallel compression for CLT increased with the thickness of lumber,while that of bending,parallel compression and rolling shear all decreased with the number of ***,layup orientation and the number of layers all had an impact on the strength of *** modes obtained from numerical simulation were basically the same as those of experimental *** was also strong alignment between theoretical value and test value for effective bending stifness and shear ***,the shear analogy method can be used to predict the mechanical properties of CLT *** study proved great potential in using Japanese larch wood for manufacturing CLT due to its good mechanical properties.

关键词： Cross-laminated timber mechanical properties lay-ups failure mode shear analogy

Kinetics of indium dissolution from marmatite with high indium content in pressure acid leaching

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Rare Metals 2017年第1期36卷 69-76页

作者： Lei tian Yan liu Ting-An Zhang Guo-Zhi Lv Shuang Zhou Guo-Quan Zhang Key Laboratory for Ecological Utilization of Multimetallic Mineral Ministry of Education Northeastern UniversityShenyang 110819 China

The kinetics of oxygen pressure acid leaching marmatite with high indium content was studied. The effects of particle size, agitation rate, temperature, HSOconcentration, and oxygen partial pressure on leaching rate of indium were investigated. The results show that when the agitation rate is above 600 r-min, its influence on indium leaching rate is insignificant. It is determined that the leaching rates increase with the increase in sulfuric acid concentration, temperature, partial oxygen pressure, and the decrease in particle size. Moreover, the results demonstrate that the process of indium leaching is controlled by interface chemical reaction, with apparent activation energy of 65.7 k J-mol. The apparent reaction orders of sulfuric acid and oxygen partial pressure are determined to be 0.749 and 1.260, respectively. The leaching reaction process follows shrinking unreacted core model. And finally, the kinetics model equation is established for indium.

关键词： Marmatite Indium Oxygen pressure acid leaching Kinetics Activation energy Reaction order

唐宋时期别史文集中南方民族地区交往、交流、交融研究

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广西民族研究 2023年第1期 141-146页

作者：田敏刘洁中南民族大学民族学与社会学学院湖北武汉430074

针对当前学界多就单一别史文集进行研究的现状,本文选取唐宋时期别史文集进行集中分析讨论,其关于社会交往、经济交流、文化交融的历史表现形式,有力阐释了历史上民族“三交”的历史生成逻辑,并表明历史上促进民族“三交”的因素与王朝... 详细信息

针对当前学界多就单一别史文集进行研究的现状,本文选取唐宋时期别史文集进行集中分析讨论,其关于社会交往、经济交流、文化交融的历史表现形式,有力阐释了历史上民族“三交”的历史生成逻辑,并表明历史上促进民族“三交”的因素与王朝的因俗而治、广开商贸、科举兴学等举措密切相关,同时也与民族地区渐归汉地、渐慕华风、渐习汉语等自身因素密不可分。南方民族地区民族间交往、交流、交融的历史表现及成因,正是我国多民族交往、交流、交融的历史写照与历史确证。

关键词：唐宋别史文集南方民族交往交流交融

Potential Bands of Sentinel-2A Satellite for Classification Problems in Precision Agriculture

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International Journal of Automation and computing 2019年第1期16卷 16-26页

作者： tian-Xiang Zhang Jin-Ya Su Cun-Jia liu Wen-Hua Chen Department of Aeronautical and Automotive Engineering Loughborough University

Various indices are used for assessing vegetation and soil properties in satellite remote sensing applications. Some indices,such as normalized difference vegetation index(NDVI) and normalized difference water index(NDWI), are capable of simply differentiating crop vitality and water stress. Nowadays, remote sensing capabilities with high spectral, spatial and temporal resolution are available to analyse classification problems in precision agriculture. Many challenges in precision agriculture can be addressed by supervised classification, such as crop type classification, disease and stress(e.g., grass, water and nitrogen) monitoring. Instead of performing classification based on designated indices, this paper explores direct classification using different bands information as features. Land cover classification by using the recently launched Sentinel-2A image is adopted as a case study to validate our method. Four approaches of featured band selection are compared to classify five classes(crop, tree, soil, water and road) with the support vector machines(SVMs)algorithm, where the first approach utilizes traditional empirical indices as features and the latter three approaches adopt specific bands(red, near infrared and short wave infrared) related to indices, specific bands after ranking by mutual information(MI), and full bands of on-board sensors as features, respectively. It is shown that a better classification performance can be achieved by directly using the selected bands after MI ranking compared with the one using empirical indices and specific bands related to indices, while the use of all 13 bands can marginally improve the classification accuracy than MI based one. Therefore, it is recommended that this approach can be applied for specific Sentinel-2A image classification problems in precision agriculture.

关键词： Sentinel-2A remote sensing image classification supervised learning precision agriculture

Street-Level IP Geolocation Algorithm Based on Landmarks Clustering

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Computers, Materials & Continua 2021年第3期66卷 3345-3361页

作者： Fan Zhang Fenlin liu Rui Xu Xiangyang Luo Shichang Ding Hechan tian PLA Strategic Support Force Information Engineering University Zhengzhou450001China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450001China Cyberspace Security Key Laboratory of Sichuan Province Chengdu610000China China Electronic Technology Cyber Security Co. Ltd.Chengdu610000China University of Goettingen Goettingen37075Germany

Existing IP geolocation algorithms based on delay similarity often rely on the principle that geographically adjacent IPs have similar ***,this principle is often invalid in real Internet environment,which leads to unreliable geolocation *** improve the accuracy and reliability of locating IP in real Internet,a street-level IP geolocation algorithm based on landmarks clustering is ***,we use the probes to measure the known landmarks to obtain their delay vectors,and cluster landmarks using ***,the landmarks are clustered again by their latitude and longitude,and the intersection of these two clustering results is taken to form training ***,we train multiple neural networks to get the mapping relationship between delay and location in each training ***,we determine one of the neural networks for the target by the delay similarity and relative hop counts,and then geolocate the target by this *** it brings together the delay and geographical coordinates clustering,the proposed algorithm largely improves the inconsistency between them and enhances the mapping relationship between *** evaluate the algorithm by a series of experiments in Hong Kong,Shanghai,Zhengzhou and New *** experimental results show that the proposed algorithm achieves street-level IP geolocation,and comparing with existing typical streetlevel geolocation algorithms,the proposed algorithm improves the geolocation reliability significantly.

关键词： IP geolocation neural network landmarks clustering delay similarity relative hop

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镁同位素体系在重要地质过程中的应用

地学前缘 2023年第3期30卷 399-424页

作者：刘嘉文田世洪王玲东华理工大学核资源与环境国家重点实验室江西南昌330013 东华理工大学地球科学学院江西南昌330013 自然资源部深地科学与探测技术实验室北京100094

Mg作为主要的造岩元素,其丰度在地球上排第四位(仅次于O、Fe和Si)。Mg在自然界中存在3种稳定同位素,分别为^(24)Mg、^(25)Mg和^(26)Mg,其中^(26)Mg和^(24)Mg之间具有较大的质量差(8.33%),在各类地质过程中显示出不同程度的分馏,使之成... 详细信息

Mg作为主要的造岩元素,其丰度在地球上排第四位(仅次于O、Fe和Si)。Mg在自然界中存在3种稳定同位素,分别为^(24)Mg、^(25)Mg和^(26)Mg,其中^(26)Mg和^(24)Mg之间具有较大的质量差(8.33%),在各类地质过程中显示出不同程度的分馏,使之成为研究不同地质演化过程的有力指标和良好示踪剂。近年来,随着分析方法的改进和同位素质谱技术的发展,Mg同位素的应用得到大跨步的发展。前人从不同角度对Mg同位素研究进展进行了综述,本文在简要介绍Mg同位素标准物质和分析方法的基础上,详细阐述了Mg同位素在地质学4个领域方面的应用,包括:(1)Mg同位素在矿床成因方面的应用,能够有效示踪成矿过程、成矿物质来源等;(2)Mg同位素在煌斑岩成因方面的应用,可有效示踪源区物质组成;(3)Mg同位素在地质温度计方面的应用,概述了较为常见的四种矿物对Mg同位素地质温度计并分析了其适用性;(4)含石榴石的变质作用、转熔反应和岩浆作用中的Mg同位素分馏及其指示意义。总之,本文通过对Mg同位素在上述重要地质过程中研究成果的系统总结,旨在加深对Mg同位素体系的深入理解,进一步显示Mg同位素体系具有非常广阔的应用前景。

关键词： Mg同位素分析方法矿床成因煌斑岩成因地质温度计变质岩浆过程

Stereoselective Synthesis of Novel C-Disaccharides via Suzuki Cross-Coupling Reaction

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Chinese Journal of Chemistry 2005年第11期23卷 1564-1568页

作者： LI, Xiao-liu XU, Xiao-Ming tian, Jun LI, Ying-Xia School of Chemistry and Environmental Sciences Hebei University Baoding Hebei 071002 China Department of Pharmaceutical Sciences Ocean University of China Qingdao Shandong 266003 China

Novel β-C-disaccharides containing a three carbon linkage using exo-glycal as the precursor were prepared stereoselectively. The synthesis was achieved by the tandem reactions of the stereoselective hydroboration of exo-glycal and Suzuki cross-coupling reaction with an iodovinyl sugar, and followed by hydrogenated deprotection under the catalysis of Pd（OH）2/C.

关键词： exo-glycal Suzuki coupling reaction C-disaccharide

Polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls in surface soil from the Tibetan Plateau

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Journal of Environmental Sciences 2014年第10期26卷 2041-2047页

作者： Zhenyu tian Haifeng Li Huiting Xie Chen Tang Ying Han Mengjing Wang Wenbin liu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences

Concentrations of Polychlorinated dibenzo-p-dioxins and dibenzofurans（PCDD/Fs） and polychlorinated biphenyls（PCBs） in soil samples from Tibetan Plateau were determined. The average concentration of total 2,3,7,8-PCDD/Fs was（2.30 ± 1.02） pg/g, and World Health Organization Toxicity Equivalency（WHO-TEQ） average concentration was（0.013 ± 0.010）pg WHO-TEQ/g. The average concentration of ∑PCBs（7 indicator PCB and 12 dioxin like-PCB congeners） was（16.2 ± 9.25） pg/g, and WHO-TEQ average concentration was 0.043 ±0.049 pg WHO-TEQ/g. Comparing to previous studies in similar environmental conditions,PCDD/Fs and PCBs in this study showed a relatively lower concentration. The altitude dependences of PCDD/Fs and PCBs were also studied. Total organic carbon（TOC） normalized concentrations presented a quadratic relation with the altitudes, and an inflection could be found on the parabola of the total concentrations and some congeners of high *** concentrations decreased with altitudes below about 4500 m above sea level（a.s.l.）, while they increased with altitudes above it. These phenomena indicate that cold condensation of PCDD/Fs and PCBs would happen above 4500 m a.s.l, on the Tibetan Plateau.

关键词： Cold-trap effect Persistent organic pollutants Indicator polychlorinated biphenyls Inflection Quadratic relation