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Camera Calibration from Profile of Revolution

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Geo-Spatial Information Science 2006年第1期9卷 38-44页

作者： zheng Shunyi YANG ling SUN Mingwei School of Remote Sensing and Information Engineering Wuhan University 129 Luoyu Road Wuhan 430079 China

This paper focuses on the problem of calibrating a pinhole camera from images of profile of a revolution. In this paper, the symmet ry of images of profiles of revolution has been extensively exploited and a prac tical and accurate technique of camera calibration from profiles alone has been developed. Compared with traditional techniques for camera calibration, for inst ance, it may involve taking images of some precisely machined calibration patter n (such as a calibration grid), or edge detection for determining vanish points which are often far from images center or even do not physically exist, or calcu lation of fundamental matrix and Kruppa equations which can be numerically unsta ble, the method presented here uses just profiles of revolution, which are commo nly found in daily life (e.g. bowls and vases), to make the process easier as a result of the reduced cost and increased accessibility of the calibration object s. This paper firstly analyzes the relationship between the symmetry property of profile of revolution and the intrinsic parameters of a camera, and then shows how to use images of profile of revolution to provide enough information for det ermining intrinsic parameters. During the process, high-accurate profile extrac tion algorithm has also been used. Finally, results from real data are presented , demonstrating the efficiency and accuracy of the proposed methods.

关键词： camera calibration profile of revolution harmonic homology symmetry

Interannual variability of thermal front west of Luzon Island in boreal winter

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Acta Oceanologica Sinica 2015年第11期34卷 102-108页

作者： SUN Ruili ling zheng CHEN Changlin YAN Yunwei College of Physical and Environmental Oceanography Ocean University of China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration

Interannual variability of thermal front west of Luzon Island during the winter of 1993-2013 is examined with the method of singular value decomposition （SVD） and a suite of satellite measurements in this paper. It is found that both the area and intensity of the thermal front west of Luzon Island show apparent interannual variability. Further study based on SVD shows that the interannual variability of the thermal front is highly associated with E1 Nifio and Southern Oscillation （ENSO）, and the correlation coefficient between Nifio3.4 index and the first Principal Component （PC1） of thermal front can reach -0.65. The mechanism can be described as follows. In E1 Nifio （La Nifia） years, the East Asian winter monsoon （EAWM） is weakened （enhanced）, inducing weaker （stronger） local wind stress curl （WSC） west of Luzon Island, and resulting in weakened （enhanced） Luzon cold eddy, which finally leads to the weakening （enhancement） of the thermal front.

关键词： thermal front interannual variability Luzon Island ENSO South China Sea

Role of ocean upper layer warm water in the rapid intensification of tropical cyclones: A case study of typhoon Rammasun(1409)

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Acta Oceanologica Sinica 2016年第3期35卷 63-68页

作者： SUN Jia ZUO Juncheng ling zheng YAN Yunwei Key Laboratory of Coastal Disaster and Defence of Ministry of Education Hohai University Institute of Physical Oceanography Hohai University State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration

Rammasun intensified rapidly from tropical storm to super typhoon in the northern South China Sea（NSCS）before its landfall on Hainan Island. Analysis of observed data shows that the anomalous ocean upper layer warm water（WW） is important to the rapid intensification of Rammasun. During the period of Rammasun, sea surface temperature（SST） in the NSCS was much warmer than the climatological SST. The anomalous WW supplied more energy to Rammasun, resulting in its rapid intensification. Numerical simulations further confirm that the NSCS WW plays an important role in the rapid intensification of Rammasun. As the WW is removed, the intensification of Rammasun is only 25 h Pa, which is 58.1% of that in the original SST-forced run.

关键词： tropical cyclone Rammasun rapid intensification warm water sea surface temperature

Six types of spin solitons in three-component Bose-Einstein condensates

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Communications in Theoretical Physics 2024年第6期76卷 57-65页

作者： Yu-Hao Wang ling-zheng Meng Li-Chen Zhao School of Physics Northwest UniversityXi'an 710127China School of Science Xi'an Technological UniversityXi'an 710032China Peng Huanwu Center for Fundamental Theory Xi'an 710127China

Exact analytical solutions are good candidates for studying and explaining the dynamics of solitons in nonlinear *** further extend the region of existence of spin solitons in the nonlinearity coefficient space for the spin-1 Bose-Einstein *** types of spin soliton solutions can be obtained,and they exist in different *** analysis and numerical simulation results indicate that three types of spin solitons are stable against weak *** non-integrable properties of the model can induce shape oscillation and increase in speed after the collision between two spin *** results further enrich the soliton family for non-integrable models and can provide theoretical references for experimental studies.

关键词： Bose-Einstein condensate non-integrable spin soliton exact analytical solution

A Lower Semicontinuity Result for Some Integral Functionals in the Space SBD

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 297-304页

作者： Zhong-xue Lu Xiao-ping Yang Min-ling zheng School of Mathematical Science Xuzhou Normal University Xuzhou 221116 China School of Science Nanjing University of Science and Technology Nanjing 210094 China School of Science Huzhou Teacher College Huzhou 313000 China

In this paper, we obtain a lower semicontinuity result with respect to the strong L1-convergence of the integral functionals F（u,Ω）=Ωf（x,u（x）,εu（x））dx defined in the space SBD of special functions with bounded deformation. Here Su represents the absolutely continuous part of the symmetrized distributional derivative Eu. The integrand f satisfies the standard growth assumptions of order p 〉 1 and some other conditions. Finally, by using this result,we discuss the existence of an constrained variational problem.

关键词： SBD space integral functionals lower semicontinuity

Effects of tidal currents on winter wind waves in the Qiongzhou Strait:a numerical study

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Acta Oceanologica Sinica 2020年第11期39卷 33-43页

作者： Peng Bai zheng ling Cong Liu Junshan Wu lingling Xie Marine Resources Big Data Center of South China Sea Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)Zhanjiang 524025China Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction College of Ocean and MeteorologyGuangdong Ocean UniversityZhanjiang 524088China Ocean College Zhejiang UniversityZhoushan 316021China East China Sea Bureau of Ministry of Natural Resources Shanghai 200137China

Effects of currents on winter wind waves in the tide-dominated Qiongzhou Strait(QS)were numerically evaluated via employing the coupled ocean-atmosphere-wave-sediment transport(COAWST)modeling *** showed satisfactory model performance in simulating the intense tidal currents in the *** effects of sea level variations and tidal currents on waves were examined under the maximum eastward(METC)and westward(MWTC)tidal *** the east entrance area of the QS,the positive sea levels under the MWTC deepened the water depth felt by waves,benefiting the further propagation of wave energy into the inner strait and causing increased wave *** METC and the MWTC could both enhance the wave height in the east entrance area of the QS,mainly through current-induced convergence and wavenumber shift,*** current-induced refraction,the METC(MWTC)triggered counterclockwise(clockwise)rotation in peak wave directions in the northern part of the QS while clockwise(counterclockwise)rotation in the southern part.

关键词： Qiongzhou Strait COAWST significant wave height peak wave direction

Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

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Rare Metals 2016年第3期35卷 242-248页

作者： ling-ling zheng Jin-Xu Liu Shu-Kui Li Shuang Liu Qing-He Zou Xing-Wang Cheng School of Materials Science and Engineering Beijing Institute of Technology Mudanjiang North Alloy Tool Co. Ltd

The W–Cu–Zn alloy with a-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering（SPS） *** effects of process and parameters on the microstructure and mechanical properties of the alloy were *** W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800℃ for 10 *** microstructure analysis shows that Cu–Zn matrix consists of nano-sized a-brass grains,and the main composition is Cu3Zn *** nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method,and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix *** dynamic compressive strength of the W–Cu–Zn alloy achieves to1000 MPa,but the alloy shows poor ductility due to the formation of the hard and brittle Cu3Zn *** fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.

关键词： W–Cu–Zn alloy Spark plasma sintering Microstructure Mechanical properties Microhardness

The effect of cataract surgery on sleep quality:a systematic review and Meta-analysis

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International Journal of Ophthalmology(English edition) 2017年第11期10卷 1734-1741页

作者： ling zheng Xiao-Hang Wu Hao-Tian Lin State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-sen UniversityGuangzhou 510060Guangdong ProvinceChina Jieyang People’s Hospital Jieyang Affiliated HospitalSun Yat-sen UniversityJieyang 522000Guangdong ProvinceChina

AIM： To evaluate the effect of cataract surgery on sleep quality and to compare the difference between ultravioletblocking clear intraocular lens（UVB-IOL） and blue-filtering intraocular lens（BF-IOL） ***： Electronic search was performed of PubM ed, MEDLINE, Embase and the Cochrane Library up to January 2016. Studies were eligible when they evaluated the sleep quality before and after cataract surgery by Pittsburgh sleep quality index（PSQI）. A random/fixed-effects Metaanalysis was used for the pooled estimate. Heterogeneity was assessed with the I2 test. RESULTS： Six studies were selected from 5623 references. Cataract surgery significantly reduced the PSQI scores at postoperative 0-3 mo [mean difference（MD） =-0.62, 95%CI：-1.14 to-0.11, P=0.02, I2=66%] and 3-12 mo（MD=-0.32, 95%CI：-0.62 to-0.02, P=0.04, I2=0）, respectively. Considering different intraocular lens（IOL） implantations, relative postoperative PSQI reduction was found for both UVB-IOL and BF-IOL, but a significant reduction was detected only for UVB-IOL. No significant difference was found with the effect of BF-IOL vs UVB-IOL on sleep quality. CONCLUSION： This study found that cataract surgery significantly improved the PSQI score-derived subjective sleep quality irrespective of the IOL type implanted. These findings highlight a substantial benefit of cataract surgery on systemic health with photoreceptive restoration in addition to visual acuity improvements.

关键词： cataract surgery intraocular lens implantation sleep quality

Quantum Tunneling Radiation of Reissner-Nordstrom de Sitter Black Hole with a Global Monopole

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Communications in Theoretical Physics 2006年第3期45卷 457-460页

作者： JIANG Qing-Quan YANG Shu-zheng LI Hui-ling Institute of Theoretical Physics West China Normal University Nanchong 637002 China

Applying Parikh＇s quantum tunneling model, we study the quantum tunneling radiation of Reissne- Nordstrom de Sitter black hole with a global monopole. The result shows that the tunneling rates at the event horizon and the cosmic horizon are related to Bekenstein-Hawking entropy if we take the energy conservation into consideration, and the true radiate spectrum is not precisely thermal.

关键词： Reissner-Nordstrom de Sitter black hole global monopole energy conservation tunneling rate