The Experts below are selected from a list of 16281 Experts worldwide ranked by ideXlab platform

Dongmei Deng - One of the best experts on this subject based on the ideXlab platform.

  • periodic propagation properties and radiation forces of focusing off Axis hollow vortex gaussian beams in a harmonic potential
    Optics Communications, 2019
    Co-Authors: Gengxin Chen, Jintao Xie, Dongsen Cai, Qiliang Sun, Dongmei Deng
    Abstract:

    Abstract Obtaining the analytical expression of focusing off-Axis hollow vortex Gaussian (HVG) beams by solving the (2 + 1) dimensionless linear Schrodinger-like equation, we perform the propagation path, the intensity and phase distributions, the center of mass, the peak intensity and the beam width with different potential widths α , different hollow orders n , different topological charges m , different off-Axis Coordinates ( X 0 , Y 0 ). In general, the off-Axis HVG beams are swirled counterclockwise and periodically focus during the propagation. The topological charge m separates the focusing center but the hollow order n concentrates the focusing area. Moreover, the off-Axis Coordinate ( X 0 , Y 0 ) significantly increases the focusing intensity and the potential width α can also increase the focusing frequency during the propagation. Interestingly, the influences of the hollow order n , the topological charge m and off-Axis Coordinate ( X 0 , Y 0 ) are the same on the peak intensity, which are different with the beam width. Furthermore, we also discuss the Poynting vector, angular momentum and radiation forces. In terms of the radiation forces, we can easily explore the position trapping particles stably regardless of the off-Axis Coordinate ( X 0 , Y 0 ) selection.

  • propagation properties of autofocusing off Axis hollow vortex gaussian beams in free space
    Optics Express, 2019
    Co-Authors: Gengxin Chen, Jintao Xie, Xiangxin Huang, Linjin Huang, Dongmei Deng
    Abstract:

    By solving the (2 + 1) dimensional Schrodinger equation in free space, we find that the autofocusing off-Axis hollow vortex Gaussian beams (HVGBs) are analytically derived for the first time. The off-Axis HVGBs can be adjusted by changing the off-Axis Coordinate (x0,y0) and topological charge n2. In particular, by increasing the off-Axis Coordinate (x0,y0), the self-focusing intensity can be increased. Besides, the self-focusing property can be more obvious. Furthermore, by increasing the hollow order n1, we can deepen the depth of focus, make the focus position further away, and increase the self-focusing intensity too. We also discuss other propagation properties that are used to enrich the autofocusing off-Axis HVGBs, such as Poynting vector, angular momentum, gradient force, and maximum scattering force during propagation.

Gengxin Chen - One of the best experts on this subject based on the ideXlab platform.

  • periodic propagation properties and radiation forces of focusing off Axis hollow vortex gaussian beams in a harmonic potential
    Optics Communications, 2019
    Co-Authors: Gengxin Chen, Jintao Xie, Dongsen Cai, Qiliang Sun, Dongmei Deng
    Abstract:

    Abstract Obtaining the analytical expression of focusing off-Axis hollow vortex Gaussian (HVG) beams by solving the (2 + 1) dimensionless linear Schrodinger-like equation, we perform the propagation path, the intensity and phase distributions, the center of mass, the peak intensity and the beam width with different potential widths α , different hollow orders n , different topological charges m , different off-Axis Coordinates ( X 0 , Y 0 ). In general, the off-Axis HVG beams are swirled counterclockwise and periodically focus during the propagation. The topological charge m separates the focusing center but the hollow order n concentrates the focusing area. Moreover, the off-Axis Coordinate ( X 0 , Y 0 ) significantly increases the focusing intensity and the potential width α can also increase the focusing frequency during the propagation. Interestingly, the influences of the hollow order n , the topological charge m and off-Axis Coordinate ( X 0 , Y 0 ) are the same on the peak intensity, which are different with the beam width. Furthermore, we also discuss the Poynting vector, angular momentum and radiation forces. In terms of the radiation forces, we can easily explore the position trapping particles stably regardless of the off-Axis Coordinate ( X 0 , Y 0 ) selection.

  • propagation properties of autofocusing off Axis hollow vortex gaussian beams in free space
    Optics Express, 2019
    Co-Authors: Gengxin Chen, Jintao Xie, Xiangxin Huang, Linjin Huang, Dongmei Deng
    Abstract:

    By solving the (2 + 1) dimensional Schrodinger equation in free space, we find that the autofocusing off-Axis hollow vortex Gaussian beams (HVGBs) are analytically derived for the first time. The off-Axis HVGBs can be adjusted by changing the off-Axis Coordinate (x0,y0) and topological charge n2. In particular, by increasing the off-Axis Coordinate (x0,y0), the self-focusing intensity can be increased. Besides, the self-focusing property can be more obvious. Furthermore, by increasing the hollow order n1, we can deepen the depth of focus, make the focus position further away, and increase the self-focusing intensity too. We also discuss other propagation properties that are used to enrich the autofocusing off-Axis HVGBs, such as Poynting vector, angular momentum, gradient force, and maximum scattering force during propagation.

Mohamad Abdul N Kadir - One of the best experts on this subject based on the ideXlab platform.

  • voltage control of three stage hybrid multilevel inverter using vector transformation
    IEEE Transactions on Power Electronics, 2010
    Co-Authors: Saad Mekhilef, Mohamad Abdul N Kadir
    Abstract:

    This paper presents a three-stage 18-level inverter design with a novel control method. The inverter consists of a series-connected main high-voltage, medium-voltage, and low-voltage stages. The high-voltage stage is made of a three-phase, six-switch conventional inverter. The medium- and low-voltage stages are made of three-level inverters constructed by H-bridge units. The proposed control strategy assumes a reference-input voltage vector and aims to operate the inverter in one state per sampling time to produce the nearest vector to that reference. The control concept is based on representing the reference voltage in 60^-spaced two-Axis Coordinate system. In this system, the inverter vectors' dimensions are integer multiples of the inverter's dc voltage, and the expression of the inverter's vectors in terms of its switching variables is straightforward. Consequently, the switching signals can be obtained by simple fixed-point calculations. The approach of the proposed control strategy has been presented, the transformed inverter vectors and their relation to the switching variables have been defined, and the implementation process has been described. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses.

Jintao Xie - One of the best experts on this subject based on the ideXlab platform.

  • periodic propagation properties and radiation forces of focusing off Axis hollow vortex gaussian beams in a harmonic potential
    Optics Communications, 2019
    Co-Authors: Gengxin Chen, Jintao Xie, Dongsen Cai, Qiliang Sun, Dongmei Deng
    Abstract:

    Abstract Obtaining the analytical expression of focusing off-Axis hollow vortex Gaussian (HVG) beams by solving the (2 + 1) dimensionless linear Schrodinger-like equation, we perform the propagation path, the intensity and phase distributions, the center of mass, the peak intensity and the beam width with different potential widths α , different hollow orders n , different topological charges m , different off-Axis Coordinates ( X 0 , Y 0 ). In general, the off-Axis HVG beams are swirled counterclockwise and periodically focus during the propagation. The topological charge m separates the focusing center but the hollow order n concentrates the focusing area. Moreover, the off-Axis Coordinate ( X 0 , Y 0 ) significantly increases the focusing intensity and the potential width α can also increase the focusing frequency during the propagation. Interestingly, the influences of the hollow order n , the topological charge m and off-Axis Coordinate ( X 0 , Y 0 ) are the same on the peak intensity, which are different with the beam width. Furthermore, we also discuss the Poynting vector, angular momentum and radiation forces. In terms of the radiation forces, we can easily explore the position trapping particles stably regardless of the off-Axis Coordinate ( X 0 , Y 0 ) selection.

  • propagation properties of autofocusing off Axis hollow vortex gaussian beams in free space
    Optics Express, 2019
    Co-Authors: Gengxin Chen, Jintao Xie, Xiangxin Huang, Linjin Huang, Dongmei Deng
    Abstract:

    By solving the (2 + 1) dimensional Schrodinger equation in free space, we find that the autofocusing off-Axis hollow vortex Gaussian beams (HVGBs) are analytically derived for the first time. The off-Axis HVGBs can be adjusted by changing the off-Axis Coordinate (x0,y0) and topological charge n2. In particular, by increasing the off-Axis Coordinate (x0,y0), the self-focusing intensity can be increased. Besides, the self-focusing property can be more obvious. Furthermore, by increasing the hollow order n1, we can deepen the depth of focus, make the focus position further away, and increase the self-focusing intensity too. We also discuss other propagation properties that are used to enrich the autofocusing off-Axis HVGBs, such as Poynting vector, angular momentum, gradient force, and maximum scattering force during propagation.

Saad Mekhilef - One of the best experts on this subject based on the ideXlab platform.

  • voltage control of three stage hybrid multilevel inverter using vector transformation
    IEEE Transactions on Power Electronics, 2010
    Co-Authors: Saad Mekhilef, Mohamad Abdul N Kadir
    Abstract:

    This paper presents a three-stage 18-level inverter design with a novel control method. The inverter consists of a series-connected main high-voltage, medium-voltage, and low-voltage stages. The high-voltage stage is made of a three-phase, six-switch conventional inverter. The medium- and low-voltage stages are made of three-level inverters constructed by H-bridge units. The proposed control strategy assumes a reference-input voltage vector and aims to operate the inverter in one state per sampling time to produce the nearest vector to that reference. The control concept is based on representing the reference voltage in 60^-spaced two-Axis Coordinate system. In this system, the inverter vectors' dimensions are integer multiples of the inverter's dc voltage, and the expression of the inverter's vectors in terms of its switching variables is straightforward. Consequently, the switching signals can be obtained by simple fixed-point calculations. The approach of the proposed control strategy has been presented, the transformed inverter vectors and their relation to the switching variables have been defined, and the implementation process has been described. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses.

  • voltage control of three stage hybrid multilevel inverter using vector transformation
    Power Electronics Machines and Drives (PEMD 2010) 5th IET International Conference on, 2010
    Co-Authors: M Abdul N Kadir, Saad Mekhilef, Mutsuo Nakaoka
    Abstract:

    Three-stage eighteen-level hybrid inverter design with novel control method are presented. The inverter consists of main high-voltage, medium-voltage and low-voltage stages connected in series from the output side. The high voltage stage is a three-phase, six-switch conventional sub-inverter. The medium and low voltage stages are made of three-level sub-inverters constructed by H-bridge units. The proposed control strategy assumes a reference input voltage vector and aims to approximate it to the nearest inverter vector. The control concept is based on holding the high voltage state as long as it is feasible to do so. The reference voltage vector has been represented in a 60°-spaced two Axis Coordinate system to reduce the computational effort. The concept of the staged-control has been presented, the transformed inverter vectors and their relation to the switching variables have been defined, and the implementation process has been described. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low switching losses.