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中耕苗间除草单体机构的研究与设计 被引量:1
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作者 马永财 李剑 +3 位作者 李永军 李玉清 张伟 车刚 《黑龙江八一农垦大学学报》 2011年第4期23-25,共3页
中耕苗间除草单体机构是保证除草效果和控制伤苗率的关键工作部件。根据现在中耕苗间除草单体机构在实际作业中普遍存在的问题,研究设计了仿形功能好、除草效果佳、伤苗率低的中耕苗间除草单体机构。该单体机构结构简单。
关键词 苗间除草 单体机构 仿形
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Growth Mechanism and Characterization of Single-crystalline Ga-doped SnO2 Nanowires and Self-organized SnO2/Ga2O3 Heterogeneous Microcomb Structures 被引量:1
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作者 Yong Su Liang Xu +1 位作者 Xue-mei Liang Yi-qing Chen 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2008年第2期181-186,共6页
Single-crystalline Ga-doped SnO2 nanowires and SnO2:Ga2O3 heterogeneous microcombs were synthesized by a simple one-step thermal evaporation and condensation method. They were characterized by means of X-ray powder d... Single-crystalline Ga-doped SnO2 nanowires and SnO2:Ga2O3 heterogeneous microcombs were synthesized by a simple one-step thermal evaporation and condensation method. They were characterized by means of X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). FE-SEM images showed that the products consisted of nanowires and mierocombs that represent a novel morphology. XRD, SAED and EDS indicated that they were single-crystalline tetragonal SnO2. The influence of experimental conditions on the morphologies of the products is discussed. The morphology of the product showed a ribbon-like stem and nanoribbon array aligned evenly along one or both side of the nanoribbon. It was found that many Ga2O3 nanoparticles deposited on the surface of the microcombs. The major core nanoribbon grew mainly along the [110] direction and the self-organized branching nanoribbons grew epitaxially along [110] or [110] orientation from the (110) plane of the stem. A growth process was proposed for interpreting the growth of these remarkable SnO2:Ga2O3 heterogeneous microcombs. Due to the heavy doping of Ga, the emission peak in photoluminescence spectra has red-shifted as well as broadened significantly. 展开更多
关键词 Microcomb NANORIBBON Photoluminescence
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On the Mechanism of Latex Particles Formation in Polymerization in Heterogeneous Monomer-Water System 被引量:2
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作者 Amos Arshaki Hovhannisyan Mishal Khaddazh Gayane Karlosi Grigoryan Narine Gevork Grigoryan 《Journal of Chemistry and Chemical Engineering》 2015年第5期363-368,共6页
Investigations show that in monomer water heterogeneous systems polymerization, located in the interface, can disperse the system. Following polymerization in the density gradient field it is shown that in such system... Investigations show that in monomer water heterogeneous systems polymerization, located in the interface, can disperse the system. Following polymerization in the density gradient field it is shown that in such systems latex particles are nucleated from monomer microdroplets, containing a certain amount of polymer molecules. It could be considered that, independently of the nature of the monomer itself, polymerization in monomer water statistic heterogeneous systems modulate emulsion polymerization process. 展开更多
关键词 POLYMERIZATION static system density gradient TURBIDITY emulsion.
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Developing rigid constraint for the estimation of pose and structure from a single image
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作者 魏宝刚 刘永怀 《Journal of Zhejiang University Science》 EI CSCD 2004年第7期773-781,共9页
Pose and structure estimation from a single image is a fundamental problem in machine vision and multiple sensor fusion and integration. In this paper we propose using rigid constraints described in different coordina... Pose and structure estimation from a single image is a fundamental problem in machine vision and multiple sensor fusion and integration. In this paper we propose using rigid constraints described in different coordinate frames to iteratively estimate structural and camera pose parameters. Using geometric properties of reflected correspondences we put forward a new concept, the reflected pole of a rigid transformation. The reflected pole represents a general analysis of transformations that can be applied to both 2D and 3D transformations. We demonstrate how the concept is applied to calibration by proposing an iterative method to estimate the structural parameters of objects. The method is based on a coarse-to-fine strategy in which initial estimation is obtained through a classical linear algorithm which is then refined by iteration. For a comparative study of performance, we also implemented an extended motion estimation algorithm (from 2D-2D to 3D-2D case) based on epipolar geometry. 展开更多
关键词 Structural constraints 3D-2D problem Rigid transformation
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