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Vision based terrain reconstruction for planet rover using a special binocular bundle adjustment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1341-1350页

作者： Min-yi SHEN zhi-yu xiang Ji-lin LIU Institute of Information and Communication Engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Key Laboratory of Information Network Technology Zhejiang University Hangzhou 310027 China

This paper presents a pure vision based technique for 3D reconstruction of planet terrain. The reconstruction accuracy depends ultimately on an optimization technique known as 'bundle adjustment'. In vision techniques, the translation is only known up to a scale factor, and a single scale factor is assumed for the whole sequence of images if only one camera is used. If an extra camera is available, stereo vision based reconstruction can be obtained by binocular views. If the baseline of the stereo setup is known, the scale factor problem is solved. We found that direct application of classical bundle adjustment on the constraints inherent between the binocular views has not been tested. Our method incorporated this constraint into the conventional bundle adjustment method. This special binocular bundle adjustment has been performed on image sequences similar to planet terrain circumstances. Experimental results show that our special method enhances not only the localization accuracy, but also the terrain mapping quality.

关键词： 3D reconstruction Binocular bundle adjustment (BBA) Scale-invariant feature transform (SIFT) Re-projectionerror RANSAC

Synergy of activating substrate and introducing C–H…O interaction to achieve Rh2(II)-catalyzed asymmetric cycloisomerization of 1,n-enynes

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Science China Chemistry 2020年第9期63卷 1230-1239页

作者： Rui Wu Kai Chen Jun Ma zhi-xiang yu Shifa Zhu Key Lab of Functional Molecular Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China Beijing National Laboratory for Molecular Sciences(BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of ChemistryPeking UniversityBeijing 100871China

We report the first Rh2(II)-catalyzed asymmetric cycloisomerization of activated enynes to provide cyclopropane-fused tetrahydropyridines in good yields and excellent enantioselectivities under mild *** activated group,CHZ(Z is electronwithdrawing group(EWG)),in the enyne substrates exerts two synergetic roles,one is to activate alkyne for the cyclopropanation reaction;the other is to introduce the C–H…O interaction between substrate and catalyst(reducing the energy barrier of the reaction).This double-mode activation was supported by both density functional theory(DFT)calculations and experimental *** strategy was also extended to other CH2 Z(Z can be OH,OMe,F)as activating groups that made the CH2 more acidic so that the substrates could also form increased C–H…O interaction with the catalyst.

关键词： asymmetric cycloisomerization chiral cyclopropane dirhodium catalysis carbene

Stereo vision based SLAM using Rao-Blackwellised particle filter

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第4期9卷 500-509页

作者： Er-yong WU Gong-yan LI zhi-yu xiang Ji-lin LIU Department of lnformation Science and Electrical Engineering Zhejiang University Hangzhou 310027 China National Laboratory of Pattern Recognition Institute of Automation CAS Beijing 100080 China

We present an algorithm which can realize mobile robot in unknown outdoor environments, which 3D stereo vision simultaneous localization and mapping （SLAM） for means the 6-DOF motion and a sparse but persistent map of natural landmarks be constructed online only with a stereo camera. In mobile robotics research, we extend FastSLAM 2.0 like stereo vision SLAM with ＂pure vision＂ domain to outdoor environments. Unlike popular stochastic motion model used in conventional monocular vision SLAM, we utilize the ideas of structure from motion （SFM） for initial motion estimation, which is more suitable for the robot moving in large-scale outdoor, and textured environments. SIFT features are used as natural landmarks, and its 3D positions are constructed directly through triangulation. Considering the computational complexity and memory consumption, Bkd-tree and Best-Bin-First （BBF） search strategy are utilized for SIFT feature descriptor matching. Results show high accuracy of our algorithm, even in the circumstance of large translation and large rotation movements.

关键词： Robot Vision based SLAM SIFT Feature management

PTCs promoted biphasic oxidation of ethylbenzene catalyzed by NHPI and CoSPc

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Chinese Chemical Letters 2012年第8期23卷 895-898页

作者： yu Lu Zhou Sha Sha Lin Dao Hong Xia yu zhi xiang College of Science State Key Laboratory of Heavy OilChina University of PetroleumQingdao 266580China

An easy workup and environmentally friendly method to convert ethylbenzene into the corresponding oxides, catalyzed by a combined catalytic system consisting of NHPI and CoSPc, was developed in a water involved liquid-liquid heterogeneous system. Experimental results showed that the reaction performed well facilitated by PTCs at multigrams material level, under which the conversion rate of ethylbenzene and the selectivity of acetophenone reached 60.6% and 95.2% after 0.5 h of reaction in oxygen atmosphere. An oxidation process was orooosed at the end of this oaoer.

关键词： Ethylbenzene Aerobic oxidation NHPI CoSPc PTC

Genetic diversity and structure of the endemic and endangered species Aristolochia delavayi growing along the Jinsha River

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Plant Diversity 2021年第3期43卷 225-233页

作者： yu-Long yu Hui-Chun Wang zhi-xiang yu Johann Schinnerl Rong Tang yu-Peng Geng Gao Chen School of Ecology and Environmental Science Yunnan UniversityKunming650091China yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations Kunming Institute of BotanyChinese Academy of SciencesKunming650201China University of Chinese Academy of Sciences Beijing100049China Sichuan Panzhihua Cycas National Nature Reserver Bureau Panzhihua617000China Department of Botany and Biodiversity Research University of ViennaRennweg 14A-1030ViennaAustria CAS Key Laboratory for Plant Biodiversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming650201China

The traditional medicinal plant,and endangered species Aristolochia delavayi(Aristolochiaceae)is an endemic species in China and occurs in the warm and dry areas along the Jinsha *** is also a specific host of the larvae of Byasa daemonius,a vulnerable *** this study,15 pairs of polymorphic microsatellite primers of *** were designed and screened based on the Simple Sequence Repeats(SSR)loci found by using the results of genome *** on these 15 SSR markers,the genetic diversity and structure of 193 individuals from ten natural populations were analyzed in *** comparison to other endemic and endangered plants in the region,the population of *** possess a relatively high genetic diversity(He=0.550,I=1.112).AMOVA analysis showed that 68.4%of the total genetic diversity was within populations and 31.6%of the variation occurred among *** was a significant genetic differentiation among natural populations of *** detectable,with low gene flow(Nm=0.591).This might be attributed to geographical barriers and limited seed *** test the isolation by distance(IBD),we performed Mantel test,which showed a significant correlation between the geographic and genetic *** order to cope with the possible biases caused by IBD,we additionally performed Bayesian genetic cluster analyses and principal coordinate analysis(PCoA).The final cluster analysis revealed three groups with distinct geographical *** fragmentation and limited gene flow between these populations may be the main reasons for the current genetic *** conservation of this species,we suggest to divide its populations into three protection management units,with subsequent focus on the Yongsheng and Luquan populations which experienced a genetic bottleneck event in the past.

关键词： Aristolochia delavayi Conservation biology Genetic diversity Genetic structure Microsatellites Genome skimming

A new member of the calix[4]crown family:Facile synthesis and characterization of a calix[4]crown-9 cone conformer

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Chinese Chemical Letters 2009年第2期20卷 143-146页

作者： Hao Hui Zhou Xian Mei Shang zhi Luo yu xiang Xia Jun Luo Guang Ya xiang Tongji School of Pharmacy Huazhong University of Science and Technology Wuhan 430030 China

25,27-Dipropoxy-p-tert-butylcalix[4]crown-9 cone conformer 5 was readily synthesized via an intramolecular cyclization strategy in good yields. The structures of all the new compounds involved were confirmed by NMR, E... 详细信息

关键词： Calixcrown-9 Cone conformation Synthesis Intramolecular cyclization

Natural products inspired[3+2]cycloaddition enables efficient construction of hydroxylated tetrahydrofuran acetals and concise syntheses of lignans

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Science China Chemistry 2024年第7期67卷 2306-2313页

作者： Dong-yue Cai Weiming Shi Zhao-Hui Jin zhi-xiang yu Jin-Xin Zhao Jian-Min yue State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University of Chinese Academy of Sciences Beijing 100049China Beijing National Laboratory for Molecular Sciences(BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of ChemistryPeking UniversityBeijing 100871China

Mimicking biosynthetic pathways of hongkonoids led to the development of a new Cu(Ⅰ)-catalyzed[3+2]cycloaddition ofα-hydroxyketone andβ-keto enol ethers,affording tetrahydrofuran acetals in a highly diastereoselective manner and 100%atom *** studies on the mechanism disclosed a concerted but asynchronous Michael addition/aldol *** the same importance,this methodology provides a practical biomimetic approach for one-step construction of the dibenzylbutyrolactol lignan backbone starting from two phenyl propane derivatives,opening up a powerful new approach for lignan synthesis,which is showcased by succinct total syntheses of two biologically important aryltetralin-type lignans,β-apopicropodophyllin and *** the mild and operationally simple conditions,the developed chemistry might have a promising prospect in potential industrial applications.

关键词： [3+2]cycloaddition transition-metal catalysis tetrahydrofuran lignans natural products

Robust object tracking with RGBD-based sparse learning

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Frontiers of Information Technology & Electronic Engineering 2017年第7期18卷 989-1001页

作者： Zi-ang MA zhi-yu xiang College of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Key Laboratory of lnformation Network Technology Hangzhou 310027 China

Robust object tracking has been an important and challenging research area in the field of computer vision for decades. With the increasing popularity of affordable depth sensors, range data is widely used in visual tracking for its ability to provide robustness to varying illumination and occlusions. In this paper, a novel RGBD and sparse learning based tracker is proposed. The range data is integrated into the sparse learning framework in three respects. First, an extra depth view is added to the color image based visual features as an independent view for robust appearance modeling. Then, a special occlusion template set is designed to replenish the existing dictionary for handling various occlusion conditions. Finally, a depth-based occlusion detection method is proposed to efficiently determine an accurate time for the template update. Extensive experiments on both KITTI and Princeton data sets demonstrate that the proposed tracker outperforms the state-of-the-art tracking algorithms, including both sparse learning and RGBD based methods.

关键词： Object tracking Sparse learning Depth view Occlusion templates Occlusion detection

Synthesis and self-association of dibenzothiophene derivatives for simulation of hydrogen bonding interaction in asphaltenes

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Petroleum Science 2015年第3期12卷 501-508页

作者： Ying-Hui Bian Shao-Tang Xu Le-Chun Song yu-Lu Zhou Li-Jun Zhu yu-zhi xiang Dao-Hong Xia State Key Laboratory of Heavy Oil Processing College of Chemical EngineeringChina University of Petroleum (East China)

The dibenzothiophene derivatives, namely 2-（dibenzothiophene-2-carbonyl）benzoic acid and 2-（diben- zothiophene-2-carbonyl）alkyl benzoate, were synthesized and characterized by nuclear magnetic resonance （1H NMR）, matrix-assisted laser desorption/ionization time of flight mass spectrometry, and elemental analysis. The self- association behavior of these dibenzothiophene derivatives in CH2C12 and CH3CN was investigated using UV-visible absorption spectroscopy, fourier transform infrared spec- troscopy, and atomic force microscopy. It was found that the carboxylic acid exhibited a strong self-association trend in CH2C12 solution at a concentration of about 5 × 10^-7 M. Hydrogen bonding of carboxyl in the dibenzoth- iophene derivatives was confirmed to be the main driving force for the formation of the carboxylic acid aggregates.

关键词： Dibenzothiophene derivatives Association Hydrogen bonding Simulation Asphaltenes