An experimental study on the current shot noise of a quantum point contact with short channel length is reported. The experimentally measured maximum energy level spacing between the ground and the first excited state...An experimental study on the current shot noise of a quantum point contact with short channel length is reported. The experimentally measured maximum energy level spacing between the ground and the first excited state of the device reached up to 7.5meV, probably due to the hard wall confinement by using shallow electron gas and sharp point contact geometry. The two-dimensionM non-equilibrium shot noise contour map shows noise suppression characteristics in a wide range of bias voltage. Fano factor analysis indicates spin-polarized transport through a short quantum point contact.展开更多
点云配准在逆向工程、三维重建和工业检测等领域有着广泛的应用。针对传统的迭代最近点(Iterative Clos⁃est Point,ICP)配准算法中存在对配准位姿要求高且收敛速度慢等问题。论文设计了一种基于方向直方图签名(Unique Sig⁃natures and H...点云配准在逆向工程、三维重建和工业检测等领域有着广泛的应用。针对传统的迭代最近点(Iterative Clos⁃est Point,ICP)配准算法中存在对配准位姿要求高且收敛速度慢等问题。论文设计了一种基于方向直方图签名(Unique Sig⁃natures and Histograms for Surface and Texture Description,SHOT)特征提取的三维点云配准算法。利用内部签名描述(Intrin⁃sic Shape Signatures,ISS)算法提取出目标点云的关键点后采用高描述性的SHOT特征描述子对关键点进行特征提取。对关键点进行随机采样后在离线计算好的模板特征中结合二次约束搜索提取出合适的配准点对,利用对偶四元素求解旋转矩阵和平移向量来实现点云的初始配准,最后利用ICP算法实现点云的精确配准。试验结果表明与传统的迭代最近点配准算法、基于快速点特征(Fast Point Feature Histograms,FPFH)配准算法等算法相比,论文算法的配准耗时进一步缩减,对不同位姿下的配准适应性高且对噪声环境下数据缺失有较好的鲁棒性。展开更多
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea under Grant No 2011-0004949
文摘An experimental study on the current shot noise of a quantum point contact with short channel length is reported. The experimentally measured maximum energy level spacing between the ground and the first excited state of the device reached up to 7.5meV, probably due to the hard wall confinement by using shallow electron gas and sharp point contact geometry. The two-dimensionM non-equilibrium shot noise contour map shows noise suppression characteristics in a wide range of bias voltage. Fano factor analysis indicates spin-polarized transport through a short quantum point contact.
文摘点云配准在逆向工程、三维重建和工业检测等领域有着广泛的应用。针对传统的迭代最近点(Iterative Clos⁃est Point,ICP)配准算法中存在对配准位姿要求高且收敛速度慢等问题。论文设计了一种基于方向直方图签名(Unique Sig⁃natures and Histograms for Surface and Texture Description,SHOT)特征提取的三维点云配准算法。利用内部签名描述(Intrin⁃sic Shape Signatures,ISS)算法提取出目标点云的关键点后采用高描述性的SHOT特征描述子对关键点进行特征提取。对关键点进行随机采样后在离线计算好的模板特征中结合二次约束搜索提取出合适的配准点对,利用对偶四元素求解旋转矩阵和平移向量来实现点云的初始配准,最后利用ICP算法实现点云的精确配准。试验结果表明与传统的迭代最近点配准算法、基于快速点特征(Fast Point Feature Histograms,FPFH)配准算法等算法相比,论文算法的配准耗时进一步缩减,对不同位姿下的配准适应性高且对噪声环境下数据缺失有较好的鲁棒性。
