نتایج جستجو برای: ray diffractions

تعداد نتایج: 303137  

1997
F. Aguado F. P. Fontan A. Formella

An efficient algorithm that dynamically calculates all possible ray paths in outdoor (macroand micro-cells and land mobile satellite, LMS) and indoor environments is presented in this paper. The algorithm is based on the sweep line technique. Additionally a quadtree (bounding box [1]) division of the study environment is used to reduce search time. For indoor and microcellular environments wall...

2002
T. A. Stephens J. Y. Y. Lin U. Kriplani

A Mössbauer powder diffractometer was used to measure diffraction patterns from polycrystalline foils of Fe3Al. The intensities of Bragg diffractions were measured as a function of the energy of the incident photon. The bcc fundamental diffractions showed large changes in intensity as the incident energy was tuned through the nuclear resonances. These variations of diffraction intensity with in...

Journal: :Scientific reports 2015
Yuwei Liu Xiaoli Zhu Yulin Gao Wenhai Zhang Quanping Fan Lai Wei Zuhua Yang Qiangqiang Zhang Feng Qian Yong Chen Weihua He Yinzhong Wu Zhuoyang Yan Yilei Hua Yidong Zhao Mingqi Cui Rong Qiu Weimin Zhou Yuqiu Gu Baohan Zhang Changqing Xie Leifeng Cao

Advances in the fundamentals and applications of diffraction gratings have received much attention. However, conventional diffraction gratings often suffer from higher-order diffraction contamination. Here, we introduce a simple and compact single optical element, named inclined rectangular aperture gratings (IRAG), for quasi suppression of higher-order diffractions. We show, both in the visibl...

2002
Daniela N. Schettino Daniel H. D. Carvalho Fernando J. S. Moreira

This work presents an algorithm to perform radiowave coverage predictions in urban environments using the Uniform Theory of Diffraction (UTD). The ray-tracing algorithm is based on the image theory for a quasi-3D environment. Multiple reflections and diffractions are considered through the separation of multipath components into four different classes, used to determine the scattered field. The...

Journal: :Journal of the Society of Materials Science, Japan 1965

2001
Qiang Sun Soon Yim Tan Kah Chan Teh

This paper presents an explicit formula for propagation path loss prediction of microcellular communication in an urban street scene. The formula is derived based on geometrical optics and diffraction theory and it takes into account multiple reflections along main streets, side streets and diffractions around corners. Comparisons between our theoretical results with measurements and ray tracin...

2014
SORINA ALEXANDRA GAREA ANDA IONELIA MIHAI EUGENIU VASILE GEORGETA VOICU

Porous clay heterostructures (PCH) based on modified montmorillonite were synthesized using different reaction conditions (different hydration degrees, pH values and reaction times). The PCH precursors and PCH were characterized using FTIR Spectroscopy and X-Ray Diffractions (XRD). The XRD results showed that basal distance of porous clay heterostructures was significantly influenced by the mod...

2001
John E. Vidale

The traveltimes of first arriving seismic rays through most velocity structures can be computed rapidly on a three-dimensional numerical grid by finite-difference extrapolation. Head waves are properly treated and shadow zones are filled by the appropriate diffractions. Differences of less than 0.11 percent are found between the results of this technique and ray tracing for a complex but smooth...

2015
Chao Lu Juliana M. P. Almeida Nan Yao Craig Arnold

Articles you may be interested in Mineralization and optical characterization of copper oxide nanoparticles using a high aspect ratio bio-template Photoexpansion and nano-lenslet formation in amorphous As2S3 thin films by 800 nm femtosecond laser irradiation J. Effect of cluster size of chalcogenide glass nanocolloidal solutions on the surface morphology of spin-coated amorphous films Structure...

Journal: :Physical review letters 2001
Y P Stetsko G Y Lin Y S Huang C H Chao S L Chang

The effects of anomalous dispersion (resonance) on multiple reflection of x rays and their interference in crystals at atomic absorption edges are studied. Intensity ratios of two inversion-symmetry-related multiple diffractions at or near absorption edges exhibit highly phase-sensitive profiles with strong asymmetric characteristics, unlike those far from the edges. A new resonance perturbatio...

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