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Poisson-Arago spot for gravitational waves

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Science China(Physics,Mechanics & Astronomy) 2021年第12期64卷 2-7页

作者： hongsheng zhang XiLong Fan School of Physics and Technology University of JinanJinan 250022China School of Physics and Technology Wuhan UniversityWuhan 430072China

For the observer at infinity, a Schwarzschild black hole serves as an attractive opaque disk with a radius of 3√3 M that will produce the diffraction pattern of gravitational waves(GWs). In this study, we demonstrate that a bright spot, which is a diffraction effect analogous to the Poisson-Arago spot in optics, will appear when an ingoing(quasi-)plane GW is diffracted by a Schwarzschild black hole. Here, we propose the diffraction effect of the GWs described by the exact diffraction solution of the GWs using the Heun function. For the first time, the Fresnel half-wave zone method is proposed to calculate the angular part of the GW scattering stripes for the observer at infinity. The prospect of observing the diffraction bright spot is discussed with an eikonal approximation. For normal incidence(quasi)-plane waves with 100 Hz(0.1 Hz) frequency diffracted by the central black hole of the Milky Way, the time delay between the Earth bathed in a bright spot and the minimum of the first dark stripe is 3.86(3860) d. We will witness the second bright fringe(40% amplitude of the central bright spot) after 6.2(6200) d. This new diffraction pattern involving the early phase of inspirals and pulsars as continuous gravitational wave sources is a potential scientific target for future space-and ground-based gravitational wave detectors, respectively.

关键词： gravitational waves diffraction black hole

Gravitational quasinormal modes of a parametrized Schwarzschild metric

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Communications in Theoretical Physics 2023年第10期75卷 121-128页

作者： Kai Lin hongsheng zhang Hubei Subsurface Multi-scale Imaging Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074HubeiChina School of Physics and Technology University of Jinan336 West Road of Nan XinzhuangJinan 250022China

Recently,a parametrized Schwarzschild metric(PSM)was proposed,in which n=2 to solve the differences of mass of M87*from different *** find the axial gravitational quasinormal modes of this metric are unstable for n>*** decay rate of the quasinormal mode of the case n<1 is much smaller than the case n=1,which can be used to differentiate the PSM from a Schwarzschild one.

关键词： black hole quasinormal mode matrix method

Seasonal effects of impervious surface estimation in subtropical monsoon regions

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International Journal of Digital Earth 2014年第9期7卷 746-760页

作者： hongsheng zhang Yuanzhi zhang Hui Lin Yuen Yuen Research Centre for Satellite Remote Sensing Institute of Space and Earth Information ScienceThe Chinese University of Hong Kong(CUHK)ShatinHong Kong Coastal Zone Studies Shenzhen Research Institute of CUHKShenzhenChina

Accurate impervious surface estimation(ISE)is challenging due to the diversity of land covers and the vegetation phenology and *** study investigates the variation of impervious surfaces estimated from different seasons of satellite images and the seasonal sensitivity of different *** Landsat ETM?images of four different seasons and two popular methods(*** neural network(ANN)and support vector machine(SVM))are employed to estimate the impervious surface on the pixel *** indicate that winter(dry season)is the best season to estimate impervious surface even though plants are not in their growing *** cloud and less variable source areas(VSA)(seasonal water body)become the major advantages of winter for the ISE,as cloud is easily confusedwith bright impervious surfaces,andwater in VSA is confusedwith dark impervious surfaces due to their similar spectral *** the seasonal sensitivity of methods,ANN appears more stable as its accuracy varied less than that obtained with ***,both the methods showed a general consistency of the seasonal changes of the accuracy,indicating that winter time is the best season for impervious surfaces estimation with optical satellite images in subtropical monsoon regions.

关键词： impervious surface seasonal effect variable source areas per-pixel ANN SVM

Aβ-ketoacyl-CoA Synthase OsCUT1 Confers Increased Drought Tolerance in Rice

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Rice science 2022年第4期29卷 353-362页

作者： GAO Xiuying zhang Ye zhang hongsheng HUANG Ji State Key Laboratory of Crop Genetics and Germplasm Enhancement College of AgricultureNanjing Agricultural UniversityNanjing 210095China Jiangsu Provincial Engineering Research Center of Seed Industry Science and Technology Nanjing 210095China Suzhou Chien-Shiung Institute of Technology Taicang 215411China

Drought stress is one of the major environmental factors affecting crop growth and *** wax plays essential roles in protecting plants from environmental stress via forming a hydrophobic barrier on leaf *** this study,we analyzed nine members(OsCUT1‒OsCUT9)ofβ-ketoacyl-CoA synthase,the rate-limiting key enzyme for cuticular wax synthesis in rice by homology search and domain *** expression levels of OsCUT genes under different abiotic stresses were investigated and OsCUT1 down-regulated by abiotic stress was selected for further function *** to the wild type,overexpression of OsCUT1(OX-OsCUT1)exhibited significantly increased drought *** wax was increased on the leaf surface of OX-OsCUT1 and the chlorophyll leaching experiment showed that the cuticular permeability was decreased in the OX-OsCUT1 ***,overexpression of OsCUT1 didn’t result in the significant changes of major agronomic *** total,these results suggested that OsCUT1 is a promising gene for engineering rice plants with enhanced drought tolerance.

关键词： rice β-ketoacyl-CoA synthase drought tolerance cuticular wax OsCUT1

Numerical Simulation of Nonlinear Three-Dimensional Waves in Water of Arbitrary Varying Topography

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China Ocean Engineering 1998年第4期13卷 383-404页

作者： Hong, Guangwen zhang, hongsheng Feng, Weibing Hohai Univ Coastal & Ocean Engn Res Inst Nanjing 210024 Peoples R China

The numerical simulation is based on the authors' high-order models with a dissipative term for nonlinear and dispersive wave in water of varying depth. Corresponding finite-difference equations and general conditions for open and fixed natural boundaries with an arbitrary reflection coefficient and phase shift are also given in this paper. The systematical tests of numerical simulation show that the theoretical models, the finite-difference algorithms and the boundary conditions can give good calculation results for the wave propagating in shallow and deep water with an arbitrary slope varying from gentle to steep.

关键词： numerical simulation nonlinear 3D waves boundary conditions

Optimization Potentials for the Waste Heat Recovery of a Gas-Steam Combined Cycle Power Plant Based on Absorption Heat Pump

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Journal of Thermal Science 2019年第2期28卷 283-293页

作者： zhang hongsheng ZHAO Hongbin LI Zhenlin HU Eric College of Machinery and Transportation Engineering China University of Petroleum School of Mechanical Engineering the University of Adelaide Beijing Key Laboratory of Process Fluid Filtration and Separation

A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.

关键词： combined cycle power plant absorption heat pump waste heat recovery evaluation criteria exergy analysis

Strip segmentation of oceanic internal waves in SAR images based on TransUNet

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Acta Oceanologica Sinica 2023年第10期42卷 67-74页

作者： Kaituo Qi hongsheng zhang Jiaojiao Lu Yinggang Zheng Zhouhao zhang College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China Translational Research Institute of Brain and Brain-Like Intelligence Shanghai Fourth People’s HospitalSchool of MedicineTongji UniversityShanghai 200434China

The development of oceanic remote sensing artificial intelligence has made possible to obtain valuable information from amounts of massive *** internal waves play a crucial role in oceanic *** obtain oceanic internal wave stripes from synthetic aperture radar(SAR)images,a stripe segmentation algorithm is proposed based on the TransUNet framework,which is a combination of U-Net and Transformer,which is also *** adjusting the number of Transformer layer,multi-layer perceptron(MLP)channel,and Dropout parameters,the influence of over-fitting on accuracy is significantly weakened,which is more conducive to segmenting lightweight oceanic internal *** results show that the optimized algorithm can accurately segment oceanic internal wave ***,the optimized algorithm can be trained on a microcomputer,thus reducing the research *** proposed algorithm can also change the complexity of the model to adapt it to different date ***,TransUNet has immense potential for segmenting oceanic internal waves.

关键词： oceanic internal waves deep learning stripe segmentation synthetic aperture radar TransUNet

Fluctuation with dust of de Sitter ground state of scalar-tensor gravity

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Science China(Physics,Mechanics & Astronomy) 2014年第3期57卷 411-417页

作者： TANG YanKe zhang hongsheng CHEN ChiYi LI XinZhou Department of Physics Dezhou University Shandong Provincial Key Laboratory of Functional Macromolecular Biophysics Dezhou University Center for Astrophysics Shanghai Normal University State Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Sciences Hangzhou Normal University Shanghai United Center for Astrophysics Shanghai Normal University

An exact de Sitter solution of scalar-tensor gravity is found in our recent work, in which the non-minimal coupling scalar is rolling along a non-constant potential. Based on this solution, a dust-filled FRW universe is explored in frame of scalar-tensor gravity in this article. The effective dark energy induced by the sole non-minimal scalar can be quintessence-like, phantom-like, and more significantly, can cross the phantom divide. The rich and varied properties of scalar-tensor gravity even with only one scalar is shown.

关键词： scalar tensor gravity de Sitter space dark energy phantom divide

Ground experimental investigations into an ejected spray cooling system for space closed-loop application

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Chinese Journal of Aeronautics 2016年第3期29卷 630-638页

作者： zhang hongsheng Li Yunze Wang Shengnan Liu Yang Zhong Mingliang School of Aeronautic Science and Engineering Beihang University School of Automation Science and Electrical Engineering Beihang University

Spray cooling has proved its superior heat transfer performance in removing high heat flux for ground applications. However, the dissipation of vapor liquid mixture from the heat sur- face and the closed-loop circulation of the coolant are two challenges in reduced or zero gravity space enviromnents. In this paper, an ejected spray cooling system for space closed-loop application was proposed and the negative pressure in the ejected condenser chamber was applied to sucking the two-phase mixture from the spray chamber. Its ground experimental setup was built and exper- imental investigations on the smooth circle heat surface with a diameter of 5 mm were conducted with distilled water as the coolant spraying from a nozzle of 0.51 mm orifice diameter at the inlet temperatures of 69.2 ℃ and 78.2 ℃ under the conditions of heat flux ranging from 69.76 W/cm2 to 311.45 W/cm2, volume flow through the spray nozzle varying from 11,22 L：h to 15.76 L·h. Work performance of the spray nozzle and heat transfer performance of the spray cooling system were analyzed; results show that this ejected spray cooling system has a good heat transfer performance and provides valid foundation for space closed-loop application in the near future.

关键词： Ejected spray cooling systemEvaluation models Ground experiment Heat transfer performance High heat flux Space closed-loop