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A rapid and accurate two-point ray tracing method in horizontally layered velocity model
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作者 田玥 陈晓非 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2005年第2期154-161,254,共9页
A rapid and accurate method for two-point ray tracing in horizontally layered velocity model is presented in this paper. Numerical experiments show that this method provides stable and rapid convergence with high accu... A rapid and accurate method for two-point ray tracing in horizontally layered velocity model is presented in this paper. Numerical experiments show that this method provides stable and rapid convergence with high accuracies, regardless of various 1-D velocity structures, takeoff angles and epicentral distances. This two-point ray tracing method is compared with the pseudobending technique and the method advanced by Kim and Baag (2002). It turns out that the method in this paper is much more efficient and accurate than the pseudobending technique, but is only applicable to 1-D velocity model. Kim's method is equivalent to ours for cases without large takeoff angles, but it fails to work when the takeoff angle is close to 90°. On the other hand, the method presented in this paper is applicable to cases with any takeoff angles with rapid and accurate convergence. Therefore, this method is a good choice for two-point ray tracing problems in horizontally layered velocity model and is efficient enough to be applied to a wide range of seismic problems. 展开更多
关键词 two-point ray tracing horizontally layered velocity model
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The Implementation of Ray Tracing Algorithm with OpenMP Parallelization
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作者 Noor Alnasser Raghad Alabssi +2 位作者 Batool Faran Latifah Alessa Naya Nagy 《Journal of Computer and Communications》 2024年第1期120-130,共11页
Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calcula... Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture. 展开更多
关键词 PARALLELIZATION ray tracing Parallel Computer Architecture OPENMP
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Point cloud-based environment reconstruction and ray tracing simulations for railway tunnel channels
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作者 Ziyi Qi Ruisi He +6 位作者 Mi Yang Xuejian Zhang Bo Ai Weiming Li Shaopeng Wang Wenpu Sun Lizhe Li 《High-Speed Railway》 2023年第4期241-247,共7页
Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing syst... Radio propagation environment plays a critical role in the performance of wireless communication systems,and understanding channel characteristics is vital for ensuring reliable communication links and optimizing system performance.Ray tracing is an effective method to investigate propagation characteristics in a complex environment,and how to quickly and accurately obtain environmental information needs to be solved.This paper presents dynamic environment reconstruction and ray tracing simulation in railway tunnel environment based on Simultaneous Localization and Mapping(SLAM)algorithm and Poisson reconstruction algorithm.Accurate channel parameters are obtained and analyzed based on ray tracing simulation.Both straight and curved tunnels are considered and investigated,and the results show the channel characteristics in complex railway tunnel environments. 展开更多
关键词 Railway communication TUNNELS ray tracing Environment reconstruction Wireless channel
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A minimum traveltime ray tracing global algorithm on a triangular net for propagating plane waves 被引量:1
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作者 于师建 刘润泽 程久龙 《Applied Geophysics》 SCIE CSCD 2010年第4期348-356,400,共10页
To address the problem of subdividing inflexible rectangular grid models and their poor definition of velocity interfaces,we propose a complex structure triangular net for a minimum traveltime ray tracing global algor... To address the problem of subdividing inflexible rectangular grid models and their poor definition of velocity interfaces,we propose a complex structure triangular net for a minimum traveltime ray tracing global algorithm.Our procedure is:(1) Subdivide a triangle grid based on the Delaunay triangular subdivision criterion and the relationships of the points,lines,and the surfaces in the subdividing area.(2) Define the topology relationships and related concepts of triangular unit ray tracing.(3) The source point and wave arrival points at any time compose the propagating plane wave and the minimum traveltime and secondary source positions are calculated during the plane wave propagation.We adopt the hyperbolic approximation global algorithm for secondary source retrieving.(4) By minimum traveltime ray tracing,collect the path from receiver to source points with the neighborhood point's traveltime and the direction of the secondary source.Numerical simulation examples are given to test the algorithm.The results show that the triangular net ray tracing method demonstrates model subdivision flexibility,precise velocity discontinuity interfaces,and accurate computations. 展开更多
关键词 triangular net ray tracing plane wave propagation secondary source
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Target-oriented Gaussian beam migration using a modif ied ray tracing scheme 被引量:5
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作者 Rui Zhang Jian-Ping Huang +1 位作者 Su-Bin Zhuang Zhen-Chun Li 《Petroleum Science》 SCIE CAS CSCD 2019年第6期1301-1319,共19页
For large-scale 3D seismic data,target-oriented reservoir imaging is more attractive than conventional full-volume migration,in terms of computation efficiency.Gaussian beam migration(GBM)is one of the most robust dep... For large-scale 3D seismic data,target-oriented reservoir imaging is more attractive than conventional full-volume migration,in terms of computation efficiency.Gaussian beam migration(GBM)is one of the most robust depth imaging method,which not only keeps the advantages of ray methods,such as high efficiency and flexibility,but also allows us to solve caustics and multipathing problems.But conventional Gaussian beam migration requires slant stack for prestack data,and ray tracing from beam center location to subsurface,which is not easy to be directly applied for target-oriented imaging.In this paper,we modify the conventional Gaussian beam migration scheme,by shooting rays from subsurface image points to receivers to implement wavefield back-propagation.This modification helps us to achieve a better subsurface illumination in complex structure and allows simple implementation for target reservoir imaging.Significantly,compared with the wavefi eld-based GBM,our method does not reconstruct the subsurface snapshots,which has higher efficiency.But the proposed method is not as efficient as the conventional Gaussian beam migration.Synthetic and field data examples demonstrate the validity and the target-oriented imaging capability of our method. 展开更多
关键词 Gaussian beam migration Target-oriented imaging ILLUMINATION ray tracing
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Marine Mobile Wireless Channel Modeling Based on Improved Spatial Partitioning Ray Tracing 被引量:4
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作者 Zhibin Gao Bang Liu +2 位作者 Zhipeng Cheng Canbin Chen Lianfen Huang 《China Communications》 SCIE CSCD 2020年第3期1-11,共11页
In 5G era,it is expected to achieve wireless network coverage including offshore areas.Modeling of marine wireless channels is the basis of constructing a marine communication system.In this paper,a communication scen... In 5G era,it is expected to achieve wireless network coverage including offshore areas.Modeling of marine wireless channels is the basis of constructing a marine communication system.In this paper,a communication scene between an unmanned aerial vehicle(UAV)and a boat is simulated to study the marine wireless channel.Firstly,an improved spatial partitioning ray tracing algorithm is proposed to track the propagation path of electromagnetic waves at sea surface.Secondly,a mobile channel is simulated and modeled based on the track results.Finally,a loss measurement is carried out in the coastal waters based on the simple wireless channel loss measuring platform,and a path loss propagation model is built.Then we compare the actual measurement data with the simulation results and find that the two are have good consistency,which further verifies the reliability of the simulation. 展开更多
关键词 MARINE wireless CHANNEL ray tracing CHANNEL MODELING path loss
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Fast ray tracing method in 3-D structure and its proof of positive definiteness 被引量:2
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作者 高尔根 Uk HAN 滕吉文 《Journal of Central South University of Technology》 EI 2007年第1期100-103,共4页
Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symm... Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symmetry block tridiagonal matrix equation set was deduced. Further, the positive definiteness of coefficient matrix was discussed, and the positive definiteness was accurately proved in a mathematical way. It assured that the algorithm was well-posed. Associated with iterative method, the solution to ray tracing can be got through step-by-step linearized iteration of the nonlinear problem. An algorithm of the whole path iterative ray tracing method in three-dimensional velocity structure was obtained. This method shows a clear and simple as well as explicit computation formula, which makes ray tracing computation easily applicable in practice. The correction vector is obtained through finding the solution to the positive definite block tridiagonal equation set, which ensures the method is robust convergence. This study offers a new kind of feasible and efficient ray tracing method for three dimensional seismic migration and tomography. Meanwhile, it also provides the prerequisite guarantee to design a fast algorithm. 展开更多
关键词 Fermat's principle ray tracing ray path POSITIVITY seismic migration TOMOGRAPHY
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Influence of Cy berKnife Prescription Isodose Line on the Discrepancy of Dose Results Calculated by the Ray Tracing and Monte Carlo Algorithms for Head and Lung Plans: A Phantom Study 被引量:2
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作者 Jing YANG Gang LIU +5 位作者 Hong-yuan LIU Xin NIE Zhi-yong YANG Jun HAN Sheng ZHANG Zhi-wen LIANG 《Current Medical Science》 SCIE CAS 2020年第2期301-306,共6页
Incorporation of the Monte Carlo(MC)algorithm in optimizing CyberKnife(CK)plans is cumbersome,and early models unconfigured MC calculations,therefore,this study investigated algorithm-based dose calculation discrepanc... Incorporation of the Monte Carlo(MC)algorithm in optimizing CyberKnife(CK)plans is cumbersome,and early models unconfigured MC calculations,therefore,this study investigated algorithm-based dose calculation discrepancies by selecting different prescription isodose lines(PIDLs)in head and lung CK plans.CK plans were based on anthropomorphic phantoms.Four shells were set at 2-60 mm from the target,and the constraint doses were adjusted according to the design stratcgy.After optimization,30%-90%PIDL plans were generated by ray tracing(RT).In the evaluation module,CK plans were recalculated using the MC algorithm.Therefore,the dosimetric parameters of different PIDL plans based on the RT and MC algorithms were obtained and analyzed.The discrepancies(mean+SD)were 3.72%+0.31%,3.40%+0.11%,3.47%+0.32%,0.17%+0.11%,0.64%+3.60%,7.73%+1.60%,14.62%+3.21%and 10.10%+1.57%for Djs,Dmeam),Dys,and coverage of the PTV,DGI,V,,V;and V,in the head plans and-6.32%+1.15%,-13.46%+0.98%,-20.63%+2.25%,-34.78%+25.03%,12248%+175.60%,-12.92%+5.41%,3.19%+4.67%and 7.13%+1.56%in the lung plans,respectively.The following parameters were significantly correlated with PIDL:dp98%at the 0.05 level and dpal,dys and dv3 at the 0.01 level for the head plans;dp98e%at the 0.05 level and do1e%,dpmeam,Ccoweange,dool,dvs and dv;at the 0.01 level for the lung plans.RT may be used to calculate the dose in CK head plans,but when the dose of organs at risk is close to the limit,it is necessary to refer to the MC results or to further optimize the CK plan to reduce the dose.For lung plans,the MC algorithm is recommended.For early models without the MC algorithm,a lower PIDL plan is recommended;otherwise,a large PIDL plan risks serious underdosage in the target area. 展开更多
关键词 CYBERKNIFE prescription isodose line Monte Carlo ray tracing PHANTOM
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RAY TRACING BEZIER SURFACE 被引量:2
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作者 Chai WeiyanNorthwestern Polytechnical University 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1990年第1期49-57,共9页
A new algorithm for ray tracing bicubic Bezier surface intersection is presented. In order to find the intersected patches more effectively, a quadtree representation for surface patches is utilized. The introduction ... A new algorithm for ray tracing bicubic Bezier surface intersection is presented. In order to find the intersected patches more effectively, a quadtree representation for surface patches is utilized. The introduction of the alternative binary tree subdivision of Bezier surface effectively improves the performance of the ray surface intersection, with the benefit of avoiding the problem that the binary tree subdivision would produce long narrow patches and speeding the intersection finding process. The algorithm has been programmed in FORTRAN-77 and on prime-550 II computer. The result shows that its structure is simple and it is easy to implement with good performance. 展开更多
关键词 NODE ray tracing BEZIER SURFACE
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Ray tracing/correlation approach to estimation of surface-based duct parameters from radar clutter 被引量:1
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作者 赵小峰 黄思训 盛峥 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第4期484-491,共8页
This paper describes a technique to estimate surface-based duct parameters by using a simple ray tracing/correlation method. The approach is novel in that it incorporates the Spearman rank-order correlation scheme bet... This paper describes a technique to estimate surface-based duct parameters by using a simple ray tracing/correlation method. The approach is novel in that it incorporates the Spearman rank-order correlation scheme between the observed surface clutter and the surface ray density for a given propagation path. The simulation results and the real data results both demonstrate the ability of this method to estimate surface-based duct parameters. Compared with the results obtained by a modified genetic algorithm combined with the parabolic wave equation, the results retrieved from the ray tracing/correlation scheme show a minor reduction in accuracy but a great improvement on computation time. Therefore the ray tracing/correlation method might be used as a precursor to more sophisticated and slower techniques, such as genetic algorithm and particle filters, by narrowing the parameter search space and providing a comprehensive and more efficient estimation algorithm. 展开更多
关键词 ray tracing Spearman rank correlation surface-based duct radar clutter
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Ray tracing of turning wave in elliptically anisotropic media with an irregular surface 被引量:1
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作者 Minghui Zhang Tao Xu +3 位作者 Zhiming Bai Youshan Liu Jue Hou Guiping Yu 《Earthquake Science》 CSCD 2017年第5期219-228,共10页
Seismic ray tracing in anisotropic media with irregular surface is crucial for the exploration of the fine crustal structure. Elliptically anisotropic medium is the type of anisotropic media with only four independent... Seismic ray tracing in anisotropic media with irregular surface is crucial for the exploration of the fine crustal structure. Elliptically anisotropic medium is the type of anisotropic media with only four independent elastic parameters. Usually, this medium can be described by only the vertical phase velocity and the horizontal phase velocity for seismic wave propagation. Model parameteri- zation in this study is described by flexible triangular grids, which is beneficial for the description of irregular surface with high degree of approximation. Both the vertical and horizontal phase velocities are defined in the triangular grids, respectively, which are used for the description of phase velocity distribution everywhere in the model by linear interpolation. We develop a shooting ray tracing method of turning wave in the elliptically anisotropic media with irregular surface. Runge-Kutta method is applied to solve the partial differential equation of seismic ray in elliptically anisotropic media. Linearly modified method is used for adjusting emergent phase angles in the shooting scheme. Numerical tests demonstrate that ray paths coincide well with analytical trajectories in trans- versely homogeneous elliptically anisotropic media. Seis- mic ray tracing results in transversely inhomogeneous elliptically anisotropic media demonstrate that our method is effective for further first-arrival tomography in ellipti- cally anisotropic media with an irregular surface. 展开更多
关键词 ray tracing Elliptically anisotropic media Vertical and horizontal phase velocity Irregular surface Triangular grids
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Locating flaws in anisotropic and inhomogeneous weldments using ray tracing method 被引量:1
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作者 赵新玉 刚铁 +1 位作者 肖定国 王浚人 《China Welding》 EI CAS 2011年第1期17-21,共5页
Ultrasonic inspections on nickel-based alloy weldments meets some difficulties due to the curvilinear propagating paths will appear in both anisotropic and inhomogeneons welded joints. Thus, it is difficult to determi... Ultrasonic inspections on nickel-based alloy weldments meets some difficulties due to the curvilinear propagating paths will appear in both anisotropic and inhomogeneons welded joints. Thus, it is difficult to determine the exact location of flaws using the traditional ultrasonic testing method which is based on the assumption that the sound beam will propagate in straight lines. In order to overcome this problem, we provide a new model-based inspection approach to locate the flaws in the nickel-based alloy weldments. Furthermore, some experimental examinations are carried out to compare the locating accuracy between the traditional and the modeled-based approach. It shows that the provided model-based inspection method is more accurate than the traditional method in inspection of the nickel-based alloy weldments. 展开更多
关键词 ultrasonic nondestructive testing nickel-based alloy weldments ray tracing
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A Preliminary Ray Tracing Approach to Computational Electromagnetics for Reverberation Chambers 被引量:1
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作者 Filip Nauwelaerts Dirk Van Troyen Guy A. E. Vandenbosch 《Journal of Electromagnetic Analysis and Applications》 2010年第8期462-466,共5页
This paper summarizes a theoretical design analysis for the implementation of an electromagnetic modeling tool, focusing on the simulation of electromagnetic field propagation inside reverberation chambers. The simula... This paper summarizes a theoretical design analysis for the implementation of an electromagnetic modeling tool, focusing on the simulation of electromagnetic field propagation inside reverberation chambers. The simulation algorithms which have been developed rely on a ray tracing technique, adapted in such a way as to maximize compatibility with the specific requirements and parameters, as applicable for reverberation chambers. The most significant example of a typical parameter is the high rate of wave reflections inside the chambers’ cavity. An implementation of the algorithms was used for simulation of several theoretically predictable cases. Study of the results of these test cases showed that some of the design decisions and algorithms used need to be reviewed in order to optimize the computational aspects of the application, such as resource management (memory, CPU time). Results of typical sample cases are re- viewed in this paper as well, in order to identify possible pitfalls and objectives for future research. 展开更多
关键词 ELECTROMAGNETIC modeling COMPUTATIONAL ELECTROMAGNETICS ray tracing
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Global heat transfer model and dynamic ray tracing algorithm for complex multiple turbine blades of Nibased superalloys in directional solidification process
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作者 Wen Wang Jian-xin Zhou +3 位作者 Zhao Guo Ya-jun Yin Xu Shen Xiao-yuan Ji 《China Foundry》 SCIE 2019年第5期326-335,共10页
High-quality solidification microstructure during directional solidification relies on precise temperature gradient control, so accurate calculation of the temperature field is critical. In this study, a 3D transient ... High-quality solidification microstructure during directional solidification relies on precise temperature gradient control, so accurate calculation of the temperature field is critical. In this study, a 3D transient global heat transfer model of directional solidification by the Bridgman method based on the finite difference method is developed. The radiation heat in this model is calculated by the discrete transfer method, and a modified method of external surface area for irregular geometric models is proposed to reduce the zigzag shape caused by finite difference grids. Considering the radiative heat transfer between any surface elements of all materials in the directional solidification furnace, a dynamic ray tracing algorithm is developed to simulate the entire process of directional solidification. Then, the simulated results are compared with the theoretical results and experimental results, respectively. Finally, based on the present model and method, the simulation program developed is applied to the directional solidification of actual castings. The simulated results are in good agreement with the experimental results, which indicate that the model and method developed in this study is effective and practical. 展开更多
关键词 RADIATIVE heat transfer ray tracing turbine BLADE directional SOLIDIFICATION numerical simulation
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Indirect-approach method for specified-end points seismic ray tracing in three dimen-sional inhomogeneous media
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作者 徐朝繁 张先康 +3 位作者 杨健 杨卓欣 邓宏钊 宋松岩 《Acta Seismologica Sinica(English Edition)》 EI CSCD 1998年第3期56-63,共8页
Generally speaking, the factors of both medium and tectonic that give rise to heterogeneity of the earth crust and mantle structures should be taken into account simultaneously in three dimensional seismic ray tracin... Generally speaking, the factors of both medium and tectonic that give rise to heterogeneity of the earth crust and mantle structures should be taken into account simultaneously in three dimensional seismic ray tracing. In this paper, the three dimensional structure models are constructed with the model similar to generation system in computer aid design and manufacturing (CAD/CAM). Based on the algorithm proposed by Cerveny et al . for complete seismic ray tracing in complex three dimensional structures, a new technique called the indirect approach method for two point seismic ray tracing in three dimensional laterally heterogeneous media has been put forward, and its numerical computing examples were given. 展开更多
关键词 3 D ray tracing CRUST mantle structure indirect approach method
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A Ray-Tracing Analysis of ICRH in Tokamaks
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作者 张新军 赵燕平 +3 位作者 秦成明 T.WlATARI R.KUMAZAWA T.SEKI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2006年第4期394-396,共3页
Power deposition profiles generated by Ion Cyclotron Resonance Heating (ICRH) in non-circular tokamaks are studied using a ray-tracing technique. The simulation results for the Experimental Advanced Superconductor T... Power deposition profiles generated by Ion Cyclotron Resonance Heating (ICRH) in non-circular tokamaks are studied using a ray-tracing technique. The simulation results for the Experimental Advanced Superconductor Tokamak (EAST) D-shaped plasma are presented. It is indicated that the spatial distributions of plasma parameters (plasma density, species temperature, minority ion concentration, etc.) have an significant influence on the power deposition profiles. The findings may be highly useful to the planned plasma heating and experiments in EAST. 展开更多
关键词 ray tracing power deposition ICRH
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Measurement and verification of concentration-dependent diffusion coefficient:Ray tracing imagery of diffusion process
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作者 Li Wei Wei-Dong Meng +2 位作者 Li-Cun Sun Xin-Fei Cao Xiao-Yun Pu 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第8期292-301,共10页
Ray tracing method is used to study the propagation of collimated beams in a liquid-core cylindrical lens(LCL),which has dual functions of diffusion cell and image formation.The diffusion images on the focal plane of ... Ray tracing method is used to study the propagation of collimated beams in a liquid-core cylindrical lens(LCL),which has dual functions of diffusion cell and image formation.The diffusion images on the focal plane of the used LCL are simulated by establishing and solving both linear and nonlinear ray equations,the calculated results indicate that the complex imaging results of LCL in inhomogeneous media can be treated by the law of ray propagation in homogeneous media under the condition of small refractive index gradient of diffusion solution.Guided by the calculation conditions,the diffusion process of triethylene glycol aqueous solution is experimentally studied at room temperature by using the LCL in this paper.The spatial and temporal concentration profile Ce(z,t)of diffusion solution is obtained by analyzing diffusion image appearing on the focal plane of the LCL;Then,the concentration-dependent diffusion coefficient is assumed to be a polynomial D(C)=D0×(1+α1C+α2C2+α3C3+…).The finite difference method is used to solve the Fick diffusion equation for calculating numerically the concentration profiles Cn(z,t).The D(C)of triethylene glycol aqueous solution is obtained by comparing the Cn(z,t)with Ce(z,t).Finally,the obtained polynomial D(C)is used to calculate the refractive index profiles nn(z,t)s of diffusion solution in the used LCL.Based on the ray propagation law in inhomogeneous media and the calculated n(z,t),the ray tracing method is used again to simulate the dynamic images of the whole experimental diffusion process to varify the correctness of the calculated D(C).The method presented in this work opens up a new way for both measuring and verifying the concentration-dependent liquid diffusion coefficients. 展开更多
关键词 concentration-dependent liquid diffusion coefficients liquid-core cylindrical lens nonlinear ray equation ray tracing method
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Ray Tracing for Doppler Backscattering System in the Experimental Advanced Superconducting Tokamak
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作者 周楚 刘阿娣 +7 位作者 胡建强 王明远 张小辉 李弘 俞昌旋 刘万东 兰涛 谢锦林 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第9期728-732,共5页
The Doppler backscattering system has been widely used for turbulence measurements,and the microwave beam will be backscattered near the cut-off layer when the Brag condition is fulfilled.In tokamak,the ray-tracing co... The Doppler backscattering system has been widely used for turbulence measurements,and the microwave beam will be backscattered near the cut-off layer when the Brag condition is fulfilled.In tokamak,the ray-tracing code is used to obtain the radial position and perpendicular wave number of the scattering layer for turbulence velocity measurement and the WKB(Wentzel-Kramers-Brillouin) approximation should be satisfied for optical propagation.To calculate the backscattering location and wave number at the cut-off layer only,a single ray tracing in the cross section is enough,while for spatial and wave number resolution calculation,multiple rays reflecting the microwave beam size should be used.Considering the angle between the wave vector and the magnetic field,a three-dimension quasi-optical Gaussian ray tracing is sometimes needed. 展开更多
关键词 Doppler backscattering system ray tracing wave number resolution pitch angle
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Ray-tracing simulations of whistler-mode wave propagation in different rescaled dipole magnetic fields
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作者 YangGuang Ke QuanMing Lu +2 位作者 XinLiang Gao HuaYue Chen Rui Chen 《Earth and Planetary Physics》 EI CSCD 2022年第6期555-562,共8页
Kinetic simulation is a powerful tool to study the excitation and propagation of whistler-mode waves in the Earth’s inner magnetosphere.This method typically applies a scaled-down dipole magnetic field to save comput... Kinetic simulation is a powerful tool to study the excitation and propagation of whistler-mode waves in the Earth’s inner magnetosphere.This method typically applies a scaled-down dipole magnetic field to save computational time.However,it remains unknown whether whistler wave propagation in the scaled-down dipole field is consistent with that in the realistic dipole field.In this work,we develop a ray-tracing code with a scalable dipole magnetic field to address this concern.The simulation results show that parallel whistler waves at different frequencies gradually become oblique after leaving the equator and propagate in different raypaths in a dipole magnetic field.During their propagation,the higher frequency waves tend to have larger wave normal angles at the same latitude.Compared with the wave propagation in a realistic dipole field,the wave raypath and wave normal remain the same,whereas the wave amplification or attenuation is smaller because of the shorter propagation time in a scaled-down dipole field.Our study provides significant guidance for kinetic simulations of whistler-mode waves. 展开更多
关键词 whistler wave ray tracing propagation dipole magnetic field MAGNETOSPHERE
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A Fast Algorithm for Ray Tracing
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作者 Tang Gangdou and Zhong PengxiangBeijing Institute of Data Processing Technology 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1992年第2期49-56,共8页
A fast algorithm for ray tracing is presented, with which the specular reflection term of global illumination model is improved. A hybrid technique combining hierarchical bounding volumes and constant size box partiti... A fast algorithm for ray tracing is presented, with which the specular reflection term of global illumination model is improved. A hybrid technique combining hierarchical bounding volumes and constant size box partitioning is presented and a fast box traversal algorithm is used. By this technique multiple ray intersections with objects that are in more than one box can be avoided. As a result, the speed of ray tracing is considerably increased. 展开更多
关键词 Global illumination model Hierarchical bounding volume Space partitioning ray tracing.
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