The Experts below are selected from a list of 3042 Experts worldwide ranked by ideXlab platform
Guan Fuling - One of the best experts on this subject based on the ideXlab platform.
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sensitivity analysis of thermal deformation of Parabolic Antenna in orbit
Journal of Engineering Design, 2010Co-Authors: Guan FulingAbstract:Thermal deformation is a main factor affecting Antenna performance.Sensitivity analysis of thermal deformation of Parabolic Antenna in orbit is the base of controlling deformation.A spline function shell element in orthogonal curvilinear coordinate system based on classic shell theory was used for Antenna thermal analysis.For a Parabolic Antenna,thermal conductivity sensitivity of root mean square of displacements(RMSD) of reflector shell was analyzed under three steady-states,result shows that the sensitivity is dependent on load cases,so the maximum of RMSD(MRMS) during an orbit period is treated as design object.Orthogonal simulation experiment method was used for sensitivity of thermal conductivity in shell plane and in transverse direction,specific heat,modulus of elasticity and thermal expansion coefficient to MRMS.The results show that in the levels thermal expansion coefficient has most,thermal conductivity has more,modulus of elasticity has less and specific heat has least influence on MRMS.The optimum parameters achieved can provide reference for ply optimization design of Parabolic Antenna in order to control the deformation.
Morozov Sergii - One of the best experts on this subject based on the ideXlab platform.
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Photonic and electric control of single photon emission from individual quantum dots
Physics Imperial College London, 2020Co-Authors: Morozov SergiiAbstract:Modern single photon quantum technologies require on-demand and deterministic sources. Single photon emission has been observed from various solid state systems, such as individual molecules, defects and colour centres in diamond and 2D materials, and artificial atoms - quantum dots. However, the quantum emitters suffer from the slow radiation rate and omnidirectional emission, preventing their practical applications. First, this Thesis proposes to exploit the charged excitonic states in individual colloidal quantum dots for the enhancement of radiation rate. Electron injection to a quantum dot increases the number of de-excitation pathways, hence boosting the single photon generation speed. The optical properties of charged excitons depend drastically on the number of injected electrons, which can be controlled by applying a voltage bias in an electrochemical cell, thus providing for an active and deterministic way to manipulate the single photon emission. The charge transfer allows for a deterministic manipulation of quantum dot photodynamics, with an observed 210-fold increase of the radiation rate, accompanied by a 12-fold decrease of the emission intensity, all while preserving single-photon emission characteristics. Secondly, this Thesis proposes a 3D metal-dielectric Parabolic Antenna with an individual quantum dot in its focal point as a source of collimated single photons which can then be easily extracted and manipulated. Compared to conventional nano-Antennas, 3D Parabolic Antenna design does not require near-field coupling, hence it is very robust against misalignment issues, and minimally affected by absorption in the metal. The Parabolic Antenna provides one of the largest reported experimental directivity (D=106) and the lowest beam divergence (13.5 deg), a broadband operation over all the visible and near-IR range, together with more than 96% extraction efficiency, offering a practical advantage for quantum technological applications.Open Acces
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A metal-dielectric Parabolic Antenna to direct single photons
'American Chemical Society (ACS)', 2018Co-Authors: Morozov Sergii, Gaio Michele, Maier, Stefan A., Sapienza RiccardoAbstract:Quantum emitters radiate light omni-directionally, making it hard to collect and use the generated photons. Here we propose a 3D metal-dielectric Parabolic Antenna surrounding an individual quantum dot as a source of collimated single photons which can then be easily extracted and manipulated. Our fabrication method relies on a single optically-induced polymerization step, once the selected emitter has been localized by confocal microscopy. Compared to conventional nano-Antennas, our geometry does not require near-field coupling and it is therefore very robust against misalignment issues, and minimally affected by absorption in the metal. The Parabolic Antenna provides one of the largest reported experimental directivities (D=106) and the lowest beam divergences ({\Theta}=13.5 deg), a broadband operation over all the visible and near-IR range, together with more than 96% extraction efficiency, offering a practical advantage for quantum technological applications.Comment: accepted for publication in Nano Letter
Hongsheng Chen - One of the best experts on this subject based on the ideXlab platform.
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non contact method to freely control the radiation patterns of Antenna with multi folded transformation optics
Scientific Reports, 2017Co-Authors: Hamza Ahmad Madni, Hongsheng Chen, Bin Zheng, Lian Shen, Zhiwei Xu, Shahram Dehdashti, Yaodong Zhao, Huaping WangAbstract:In this paper, we propose to use multi-folded transformation optics method to design a non-contact illusion device that can distantly and freely manipulate the radiation behavior of Antenna located at a certain distance and such manipulation is enabled by the use of mapped electromagnetic medium coated with the transformed medium. The proposed design aims to achieve the radiation pattern of our choice from the Antenna that does not possess any electromagnetic medium. Based on this, the functionality of Parabolic Antenna is distantly achieved from the point source. We further extended our idea to array of Antennas in which the proposed device distantly makes the linear array of Antennas behave like a geometrically different array of Antennas. Our work extends the concept of illusion optics for active scatterer that will be very helpful for future Antenna design.
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Planar focusing Antenna design by using coordinate transformation technology
Applied Physics Letters, 2007Co-Authors: Fanmin Kong, B.-i Wu, Sheng Xi, J.a. Kong, Jiangtao Huangfu, Hongsheng ChenAbstract:The coordinate transformation by using form-invariant transformations of Maxwell equations has led to an approach for designing devices with anisotropic metamaterial. In this paper, we present the design methodology for a low profile planar focusing Antenna based on the transformation of a Parabolic Antenna. The electromagnetic behavior of the planar Antenna is simulated by a two-dimensional finite element method and the results show that the planar Antenna has the same performances as the Parabolic Antenna. The coordinate transformation technology provides an alternative design method to the conventional Antennas.
Takemasa Miyoshi - One of the best experts on this subject based on the ideXlab platform.
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precipitation nowcasting with three dimensional space time extrapolation of dense and frequent phased array weather radar observations
Weather and Forecasting, 2016Co-Authors: Shigenori Otsuka, Gulanbaier Tuerhong, Ryota Kikuchi, Yoshikazu Kitano, Yusuke Taniguchi, Juan Ruiz, Shinsuke Satoh, Tomoo Ushio, Takemasa MiyoshiAbstract:AbstractThe phased-array weather radar (PAWR) is a new-generation weather radar that can make a 100-m-resolution three-dimensional (3D) volume scan every 30 s for 100 vertical levels, producing ~100 times more data than the conventional Parabolic-Antenna radar with a volume scan typically made every 5 min for 15 scan levels. This study takes advantage of orders of magnitude more rapid and dense observations by PAWR and explores high-precision nowcasting of 3D evolution at 1–10-km scales up to several minutes, which are compared with conventional horizontal two-dimensional (2D) nowcasting typically at O(100) km scales up to 1–6 h. A new 3D precipitation extrapolation system was designed to enhance a conventional algorithm for dense and rapid PAWR volume scans. Experiments show that the 3D extrapolation successfully captured vertical motions of convective precipitation cores and outperformed 2D nowcasting with both simulated and real PAWR data.
Sapienza Riccardo - One of the best experts on this subject based on the ideXlab platform.
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A metal-dielectric Parabolic Antenna to direct single photons
'American Chemical Society (ACS)', 2018Co-Authors: Morozov Sergii, Gaio Michele, Maier, Stefan A., Sapienza RiccardoAbstract:Quantum emitters radiate light omni-directionally, making it hard to collect and use the generated photons. Here we propose a 3D metal-dielectric Parabolic Antenna surrounding an individual quantum dot as a source of collimated single photons which can then be easily extracted and manipulated. Our fabrication method relies on a single optically-induced polymerization step, once the selected emitter has been localized by confocal microscopy. Compared to conventional nano-Antennas, our geometry does not require near-field coupling and it is therefore very robust against misalignment issues, and minimally affected by absorption in the metal. The Parabolic Antenna provides one of the largest reported experimental directivities (D=106) and the lowest beam divergences ({\Theta}=13.5 deg), a broadband operation over all the visible and near-IR range, together with more than 96% extraction efficiency, offering a practical advantage for quantum technological applications.Comment: accepted for publication in Nano Letter
