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

  • propagation of cosine complex variable function airy gaussian beams through the gradient index medium
    Applied Physics B, 2019
    Co-Authors: Zishuai Zeng, Kangzhu Zhou, Dongmei Deng
    Abstract:

    We introduce a new class of cosine complex variable function Airy–Gaussian (Cos-CVFAiG) beams and investigate their propagation through the gradient-index medium. Deriving the analytical expression, we show the intensity and phase Distributions, the propagation trajectory and the Poynting vector. We carry out the numerical experiment to verify the rationality of the model and find that the light intensity Distribution is parallel to the y axis in the transverse plane. With the Distribution Factor increasing, the axial intensity maximum and the number of the side lobes increase as well. Additionally, the Distribution Factor can change the bend extent of the ballistic trajectory and the intensity Distribution region in the x–z plane. We also compare the influences of the gradient refractive index coefficient with the Distribution Factor on the propagation properties.

  • paraxial propagation of radially polarized first order chirped airy guassian beams in uniaxial crystals orthogonal to the optical axis
    Applied Physics B, 2019
    Co-Authors: Jintao Xie, Dongmei Deng
    Abstract:

    We have studied the propagation of radially polarized first-order chirped Airy Guassian beams (RPCAiGBs) in uniaxial crystals orthogonal to the optical axis. The intensity Distribution, the maximum intensity, the propagation trajectory and velocity of the beams in different view planes are investigated in this paper. We find that for the x component (RPCAiGXBs) and the y component (RPCAiGYBs) of the RPCAiGBs, the intensity first propagates along the x and y directions, respectively. Later, the intensity of these two components flows into the side lobes along the x direction. We also examine the effects on the trajectory, the velocity and the focused performance of the RPCAiGBs caused by the Distribution Factor (\(\chi _0\)), the first-order chirp parameter (\(\beta \)) and the ratio of the extraordinary refractive index (\(n_\mathrm{e}\)) to the ordinary refractive index (\(n_\mathrm{o}\)) (\(n_\mathrm{e}/n_\mathrm{o}\)). Thus, by choosing appropriate \(\chi _0\), \(n_\mathrm{e}/n_\mathrm{o}\) and \(\beta \), we are able to adjust these characteristics.

  • effects of the cosine complex variable function on the airy gaussian and airy gaussian vortex beams in a chiral medium
    OSA Continuum, 2019
    Co-Authors: Jintao Xie, Kuangling Guo, Shijie Chen, Jianbin Zhang, Dongmei Deng
    Abstract:

    We introduce new kinds of beams, cos-Airy-Gaussian and the cos-Airy-Gaussian-vortex beams, which in theory can be achieved by adding a cosine complex variable function onto normal beams. The analytical expressions for these beams propagating in a chiral medium are deduced, and we focus on exploring the effects of the cosine Factor on them. It is shown that the cosine Factor can eliminate the central lobe and the x-direction side lobe of the origin intensity Distribution when the Airy-Gaussian beams tend to be Airy beams. During propagation, the intensity of the cos-Airy-Gaussian beams transfers from the side lobe in the y-direction to a certain lobe and finally flows to the side lobe in the x-direction. Moreover, the cos-Airy-Gaussian beams have a special transverse displacement along the z-axis when the Distribution Factor χ0 is small, which is unpredictable in analytical expressions unlike the normal Airy-Gaussian beams. In addition, we have developed several new formulae about the ultimate transverse displacements and the overlap position of the beams and the optical vortex, which have not been used before, and we find that there are always ultimate transverse displacements of the Airy-Gaussian beams and vortex because of the existence of the Distribution Factor χ0.

  • propagation properties and radiation forces of the airy gaussian vortex beams in a harmonic potential
    Optics Express, 2017
    Co-Authors: Zihao Pang, Dongmei Deng
    Abstract:

    We investigate the propagation properties and the radiation forces of Airy Gaussian vortex (AiGV) beams in a harmonic potential analytically and numerically in this paper. Obtaining the propagation expression of AiGV beams by solving the dimensionless linear (2+1) D Schrodinger equation in a harmonic potential, we perform the track, the intensity and phase Distributions, the propagation shapes, the energy flow and the angular momentum of AiGV beams in a harmonic potential with the method of numerical simulations. The trajectory acting like a cosine curve is shown. Periodic inversion and phase oscillation are demonstrated during propagation. The influence of the Distribution Factor and the vortex Factor on the propagation of AiGV beams in a harmonic potential are discussed. Likewise, the motion of the Poynting vector and the angular momentum is elucidated respectively. As for the radiation forces, we explore the gradient and scattering forces on Rayleigh dielectric particles induced by AiGV beams. In particular, it’s found that the value of the scattering force is approximately seven orders of magnitude larger than that of the gradient force during the propagation in a harmonic potential.

  • nonparaxial propagation of an airy gaussian beam in uniaxial crystal orthogonal to the optical axis
    Optics Communications, 2016
    Co-Authors: Fu Deng, Dongmei Deng
    Abstract:

    Abstract We have analytically investigated the nonparaxial propagation of an Airy-Gaussian beam (AiGB) in uniaxial crystal orthogonal to the optical axis. The analytical expressions of the three components are obtained, and the numerical examples are demonstrated. The influences of the uniaxial crystal and the Distribution Factor of AiGB are investigated. When the Distribution Factor is small, the AiGB tends to be an Airy beam, which has different accelerating properties on different directions in uniaxial crystal. When the Distribution Factor is large, the AiGB tends to be a Gaussian beam, which has different shapes in the x-direction and the y-direction in uniaxial crystal. And in different uniaxial crystals, the AiGB obeys different propagation regulations, and the accelerating property of the AiGB can be modulated by the uniaxial crystals.

Nasser D Elali - One of the best experts on this subject based on the ideXlab platform.

  • wheel load Distribution on simply supported skew i beam composite bridges
    Journal of Structural Engineering-asce, 1993
    Co-Authors: Alfred G Bishara, Maria Chuan Liu, Nasser D Elali
    Abstract:

    This paper presents Distribution Factor expressions for wheelload Distribution to interior and exterior girders of concrete on multisteel beam composite bridges of medium span length. These express...

  • wheel load Distribution on simply supported skew i beam composite bridges
    Journal of Structural Engineering-asce, 1993
    Co-Authors: Alfred G Bishara, Nasser D Elali
    Abstract:

    This paper presents Distribution Factor expressions for wheel‐load Distribution to interior and exterior girders of concrete on multisteel beam composite bridges of medium span length. These expressions were derived from finite element analysis of 36 bridges: with 9 ft spacing of girders, different spans (75, 100, and 125 ft), different widths (39, 57, and 66 ft), different skew angles (0°, 20°, 40°, and 60°), and different spacing and size of intermediate cross frames. The analysis recognizes the three‐dimensional interaction of all bridge members, places the bearings at their actual location, and considers the effect of the restraining forces at the bolster and rocker bearings. To test the validity of the adopted discretization scheme, its results were validated by testing an actual 137 ft. span four‐lane, 59.5° skew bridge. The derived Distribution Factor expressions give values that are generally much lower than the current American Association of State Highway Transportation Officials (AASHTO) values...

Miguel Szekely - One of the best experts on this subject based on the ideXlab platform.

  • income Distribution Factor endowments and trade openness
    Journal of Development Economics, 1999
    Co-Authors: Antonio Spilimbergo, Juan Luis Londono, Miguel Szekely
    Abstract:

    Abstract This paper studies the empirical links among Factor endowments, trade and personal income Distribution. By using panel data, we show that land and capital intensive countries have a less equal income Distribution while skill intensive countries have a more equal income Distribution. We also show that the effects of trade openness on inequality depend on Factor endowments in a way consistent with several recent case studies but not with the simple Hecksher–Ohlin framework. Our results are robust to the division of the sample according to level of income, the inclusion of different regressors, the use of different measures of trade openness and of relative Factor abundance, and tests for possible problems of endogeneity.

  • income Distribution Factor endowments and trade openness
    Research Department Publications, 1997
    Co-Authors: Antonio Spilimbergo, Juan Luis Londono, Miguel Szekely
    Abstract:

    This paper studies the empirical links among Factor endowments, trade, and personal income Distribution. The motivation is that many developing countries have implemented radical trade reforms in recent years. These reforms have changed relative prices, induced a reallocation of resources, and may have led to the introduction of new production techniques. These changes are quite complex and their final effect on income Distribution is theoretically unclear. The author`s aim is to present the stylized empirical facts on the relations between income Distribution, Factor endowments, and trade.

Alfred G Bishara - One of the best experts on this subject based on the ideXlab platform.

  • wheel load Distribution on simply supported skew i beam composite bridges
    Journal of Structural Engineering-asce, 1993
    Co-Authors: Alfred G Bishara, Maria Chuan Liu, Nasser D Elali
    Abstract:

    This paper presents Distribution Factor expressions for wheelload Distribution to interior and exterior girders of concrete on multisteel beam composite bridges of medium span length. These express...

  • wheel load Distribution on simply supported skew i beam composite bridges
    Journal of Structural Engineering-asce, 1993
    Co-Authors: Alfred G Bishara, Nasser D Elali
    Abstract:

    This paper presents Distribution Factor expressions for wheel‐load Distribution to interior and exterior girders of concrete on multisteel beam composite bridges of medium span length. These expressions were derived from finite element analysis of 36 bridges: with 9 ft spacing of girders, different spans (75, 100, and 125 ft), different widths (39, 57, and 66 ft), different skew angles (0°, 20°, 40°, and 60°), and different spacing and size of intermediate cross frames. The analysis recognizes the three‐dimensional interaction of all bridge members, places the bearings at their actual location, and considers the effect of the restraining forces at the bolster and rocker bearings. To test the validity of the adopted discretization scheme, its results were validated by testing an actual 137 ft. span four‐lane, 59.5° skew bridge. The derived Distribution Factor expressions give values that are generally much lower than the current American Association of State Highway Transportation Officials (AASHTO) values...

Loi Lei Lai - One of the best experts on this subject based on the ideXlab platform.

  • augmented power dispatch for resilient operation through controllable series compensation and n 1 1 contingency assessment
    Energies, 2021
    Co-Authors: Liping Huang, Zhaoxiong Huang, Chun Sing Lai, Guangya Yang, Zhuoli Zhao, Ning Tong, Loi Lei Lai
    Abstract:

    Research on enhancing power system resilience against extreme events is attracting significant attention and becoming a top global agenda. In this paper, a preventive augmented power dispatch model is proposed to provide a resilient operation. In the proposed model, a new N-1-1 security criterion is proposed to select disruptive N-1-1 contingency cases that might trigger cascading blackouts, and an iterative contingency assessment process based on the line outage Distribution Factor is proposed to deal with security constraints. In terms of optimization objectives, two objectives related to power flow on the transmission line are considered to reduce the possibility of overload outages. Controllable series compensation devices are also considered in the model to improve the power flow Distribution. Case studies conducted on the modified IEEE 30-bus, 118-bus and Polish 2382-bus systems show that the power flow solution of the proposed power dispatch model can avoid some branches from undertaking excessively heavy loads, especially lines forecasted to be affected by extreme events. The results of blackout simulations through a hidden failure cascading outage simulation model show that the average power losses of the proposed model are reduced by around 40% in some cases as compared to the classical economic dispatch model.