This paper proposes a universal spin-dependent variable range hopping theoretical model to describe various experimental transport phenomena observed in wide-band-gap oxide ferromagnetic semiconductors with high trans...This paper proposes a universal spin-dependent variable range hopping theoretical model to describe various experimental transport phenomena observed in wide-band-gap oxide ferromagnetic semiconductors with high transition metal concentration. The contributions of the ＇hard gap＇ energy, Coulomb interaction, correlation energy, and exchange interaction to the electrical transport are considered in the universal variable range hopping theoretical model. By fitting the temperature and magnetic field dependence of the experimental sheet resistance to the theoretical model, the spin polarization ratio of electrical carriers near the Fermi level and interactions between electrical carriers can be obtained.展开更多
Polarization-sensitive optical coherence tomo- graphy （PS-OCT） enables depth-resolved mapping of sample polarization information, such as phase-retardation and optical axis orientation, which is particularly useful ...Polarization-sensitive optical coherence tomo- graphy （PS-OCT） enables depth-resolved mapping of sample polarization information, such as phase-retardation and optical axis orientation, which is particularly useful when the nano-scale organization of tissue that are difficult to be observed in the intensity images of a regular optical coherence tomography （OCT）. In this review, we survey two types of methods and systems of PS-OCT. The first type is PS-OCT with single input polarization state, which contain bulk optics or polarization maintaining fiber （PMF） based systems and single-mode fiber （SMF） based systems. The second type is PS-OCT with two different input polarization states, which contain SMF based systems and PMF based systems, through either time, frequency, or depth multiplexing. In addition, representa- tive biomedical applications using PS-OCT, such as retinal imaging, skin cancer detection, and brain mapping, are demonstrated.展开更多
为了充分利用非圆信号共轭相关不为零的特性,提高空间到达角(direction of arrival,DOA)和极化参数估计精度,提出了一种信号DOA和极化参数估计的稳健算法.即构造2个非圆信号的4阶累积量矩阵,引入旋转不变子空间(estimation of signal pa...为了充分利用非圆信号共轭相关不为零的特性,提高空间到达角(direction of arrival,DOA)和极化参数估计精度,提出了一种信号DOA和极化参数估计的稳健算法.即构造2个非圆信号的4阶累积量矩阵,引入旋转不变子空间(estimation of signal parameters via rotational invariance techniques,ESPRIT)算法思想,利用这2个矩阵之间的旋转不变特性求出旋转因子,实现信号DOA和极化参数更精确估计.与2阶相域ESPRIT相比,改进的算法适用于任意极化状态的信号,提高估计信号的利用率,同时利用4阶累积量对高斯噪声的抑制性处理相关噪声,使估计信号的精度有了明显提升,并通过仿真结果验证了改进算法的有效性.展开更多
基金Project supported by the National Basic Research Program of China (Grant Nos. 2007CB924903 and 2009CB929202)the National Natural Science Foundation of China (Grant No. 10974120)
文摘This paper proposes a universal spin-dependent variable range hopping theoretical model to describe various experimental transport phenomena observed in wide-band-gap oxide ferromagnetic semiconductors with high transition metal concentration. The contributions of the ＇hard gap＇ energy, Coulomb interaction, correlation energy, and exchange interaction to the electrical transport are considered in the universal variable range hopping theoretical model. By fitting the temperature and magnetic field dependence of the experimental sheet resistance to the theoretical model, the spin polarization ratio of electrical carriers near the Fermi level and interactions between electrical carriers can be obtained.
文摘Polarization-sensitive optical coherence tomo- graphy （PS-OCT） enables depth-resolved mapping of sample polarization information, such as phase-retardation and optical axis orientation, which is particularly useful when the nano-scale organization of tissue that are difficult to be observed in the intensity images of a regular optical coherence tomography （OCT）. In this review, we survey two types of methods and systems of PS-OCT. The first type is PS-OCT with single input polarization state, which contain bulk optics or polarization maintaining fiber （PMF） based systems and single-mode fiber （SMF） based systems. The second type is PS-OCT with two different input polarization states, which contain SMF based systems and PMF based systems, through either time, frequency, or depth multiplexing. In addition, representa- tive biomedical applications using PS-OCT, such as retinal imaging, skin cancer detection, and brain mapping, are demonstrated.
文摘为了充分利用非圆信号共轭相关不为零的特性,提高空间到达角(direction of arrival,DOA)和极化参数估计精度,提出了一种信号DOA和极化参数估计的稳健算法.即构造2个非圆信号的4阶累积量矩阵,引入旋转不变子空间(estimation of signal parameters via rotational invariance techniques,ESPRIT)算法思想,利用这2个矩阵之间的旋转不变特性求出旋转因子,实现信号DOA和极化参数更精确估计.与2阶相域ESPRIT相比,改进的算法适用于任意极化状态的信号,提高估计信号的利用率,同时利用4阶累积量对高斯噪声的抑制性处理相关噪声,使估计信号的精度有了明显提升,并通过仿真结果验证了改进算法的有效性.
