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A Mean Curvature Regularized Based Model for Demodulating Phase Maps from Fringe Patterns

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Communications in Computational Physics 2018年第6期24卷 27-43页

作者： Carlos Brito-Loeza Ricardo Legarda-Saenz Arturo Espinosa-Romero Anabel Martin-Gonzalez CLIR at Facultad de Matematicas Universidad Autonoma de YucatanMexico

We introduce a variationalmethod for demodulating phasemaps fromfringe *** newmethod is based on themean curvature of the level sets of the phase surface that is used for *** performance of the method is illustrated w... 详细信息

关键词： Fringe analysis interferometry high-order regularization variational models

Intra-and interobserver reliability of ocular surface analyzer LacryDiag

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International Journal of Ophthalmology(English edition) 2024年第8期17卷 1418-1422页

作者： Eva Kos Valentina Cigić Mladen Bušić Mirjana Bjeloš Daliborka Miletić Biljana KuzmanovićElabjer University Eye Clinic University Hospital“Sveti Duh”Sveti Duh 64Zagreb 10000Croatia Faculty of Dental Medicine and Health Care Osijek Faculty of Medicine OsijekUniversity Josip Juraj Strossmayer in OsijekOsijek 31000Croatia

AIM:To invastigate intra-and interobserver reliability of interferometry,tear meniscus height(TMH)measurement and meibography(MBG)of an ocular surface analyzer,LacryDiag(Quantel Medical,France).METHODS:Five consecutive measurements and subsequent analysis of interferometry,TMH,and MBG were recorded by two examiners using the *** assess intra-and interobserver reliability,we used Cohen’s kappa for categorical variables(interferometry),or intraclass correlation coefficient for continuous variables(TMH,MBG).RESULTS:Thirty eyes of 30 examinees were *** both observers,there was excellent intraobserver reliability for MBG(0.955 and 0.970 for observer 1 and 2,respectively).Intraobserver reliability for observer 1 was substantial for interferometry(0.799),and excellent for TMH(0.863).Reliability for observer 2 was moderate for interferometry(0.535)and fair to good for TMH(0.431).Interobserver reliability was poor for interferometry(0.074)and fair to good for TMH(0.680)and MBG(0.414).CONCLUSION:LacryDiag ocular surface analyzer in our study proves to be a reliable noninvasive tool for the evaluation of TMH and *** for interferometry,poor interobserver reliability,fair to good intraobserver reliability for observer 1,and moderate for observer 2,leave room for improvement.

关键词： dry eye ocular surface analyzer interferometry tear meniscus height meibography

Fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse quasicrystals

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Optoelectronics Letters 2011年第5期7卷 346-349页

作者：阳明仰周骏 L Petti S De Nicola P Mormile Institute of Photonics Faculty of Science Ningbo University Istituto di Cibernetica "E. Caianiello" del Consiglio Nazionale delle Ricerche Via Campi Flegrei 34 Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche Via Campi Flegrei 34 Istituto di Cibernetica"E. Caianiello"del Consiglio Nazionale delle Ricerche Via Campi Flegrei 34

We report a numerical method to analyze the fractal characteristics of far-field diffraction patterns for two-dimensional Thue-Morse (2-D TM) structures. The far-field diffraction patterns of the 2-D TM structures can be obtained by the numerical method, and they have a good agreement with the experimental ones. The analysis shows that the fractal characteristics of far-field diffraction patterns for the 2-D TM structures are determined by the inflation rule, which have potential applications in the design of optical diffraction devices.

关键词： Diffraction patterns Fractals interferometry Two dimensional

Corrections to the IAU 1976 precession constant and the coefficients of the IAU 1980 nutation series from VLBI observations

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Chinese Science Bulletin 1998年第12期43卷 1019-1022页

作者： Li Jinling Wang Guangli Chinese Acad Sci Shanghai Observ Joint Radio Astron Res Lab Shanghai 200030 Peoples R China

In the aspect of examination by observations and based on a longer data span and improved precision of very_long baseline interferometry observations, the corrections to the IAU 1976 precession constant and the coefficients of IAU 1980 nutation series are solved. The corrections to coefficients of long periodic terms, the detection of the retrograde free core nutation, and the possible relation between the corrections to coefficients of the prograde annual term and the enviromental temperature are also briefly discussed.

关键词： very long baseline interferometry (VLBI) precession nutation corrections to coefficients.

Combined optical fiber interferometric sensors for the detection of acoustic emission

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Optoelectronics Letters 2008年第3期4卷 184-187页

作者： LIANG Yi-jun MU Lin-lin LIU Jun-feng YU Xiao-tao College of science Harbin Engineering University Harbin 150001 China

A type of combined optical fiber interferometric acoustic emission sensor is proposed. The sensor can be independent on the laser source and make light interference by matching the lengths of two arms,so it can be used to monitor the health of large structure. Theoretical analyses indicate that the system can be equivalent to the Michelson interferometer with two optical fiber loop reflectors,and its sensitivity has been remarkably increased because of the decrease of the losses of light energy. PZT is powered by DC regulator to control the operating point of the system,so the system can accurately detect feeble vibration which is generated by ultrasonic waves propagating on the surface of solid. The amplitude and the frequency of feeble vibration signal are obtained by detecting the output light intensity of interferometer and using Fourier transform technique. The results indicate that the system can be used to detect the acoustic emission signals by the frequency characteristics.

关键词： Acoustic emissions Acoustics Electric network analysis Fiber optics Fibers Fourier transforms Geodetic satellites Interferometers interferometry Lattice vibrations Light sources Michelson interferometers Optical fibers Optical in Acoustic emission sensors Acoustic Emission signals Fiber loop reflectors Fourier Frequency characteristics Interferometric sensors Laser sources Light energy Light intensities Operating points Optical Vibration signals

Experimental analysis for thermal stress in functionallygradient material

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Chinese Science Bulletin 1998年第10期43卷 827-829页

作者： Yilan Kang Qianjun Xu Shouwen Yu Tianjin Univ Dept Mech Tianjin 300072 Peoples R China Tsing Hua Univ Dept Engn Mech Beijing 100084 Peoples R China

Studies of displacement fields and stress concentration, due to uniform temperature change in a functionally gradient material (FGM) specimen and bimaterial (NFGM) specimen, have been made by Moire interferometry and finite element method. Results show that the thermal stresses concentration has been effectively reduced, and the distribution of the thermal deformations and thermal strains have also been relaxed and improved by transition layer of FGM.

关键词： functionally gradient material (FGM) Moire interferometry concentration of thermal stress.

Detecting remotely triggered temporal changes around the Parkfield section of the San Andreas fault

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Earthquake Science 2010年第5期23卷 497-509页

作者： Peng Zhao Zhigang Peng Karim Ghazi Sabra School of Earth and Atmospheric Science Georgia Institute of Technology Atlanta GA 30338 USA School of Mechanical Engineering Georgia Institute of Technology Atlanta GA 30338 USA

Detecting temporal changes in fault zone properties at seismogenic depth have been a long-sought goal in the seismological community for many decades. Recent studies based on waveform analysis of repeating earthquakes have found clear temporal changes in the shallow crust and around active fault zones associated with the occurrences of large nearby and teleseismic earthquakes. However, repeating earthquakes only occur in certain locations and their occurrence times cannot be controlled, which may result in inadequate sampling of the interested regions or time periods. Recent developments in passive imaging via auto- and cross-correlation of ambient seismic wavefields （e.g., seismic noise, earthquake coda waves） provide an ideal source for continuous monitoring of temporal changes around active fault zones. Here we conduct a systematic search of temporal changes along the Parkfield section of the San Andreas fault by cross-correlating relatively high-frequency （0.4-1.3 Hz） ambient noise signals recorded by 10 borehole stations in the High Resolution Seismic Network. After using stretch/compressed method to measure the delay time and the decorrelation-index between the daily noise cross-correlation functions （NCCFs）, we find clear temporal changes in the median seismic velocity and decorrelation-index associated with the 2004 M6.0 Parkfield earthquake. We also apply the same procedure to the seismic data around five regional/teleseismic events that have triggered non-volcanic tremor in the same region, but failed to find any clear temporal changes in the daily NCCFs. The fact that our current technique can detect temporal changes from the nearby but not regional and teleseismic events, suggests that temporal changes associated with distance sources are very subtle or localized so that they could not be detected within the resolution of the current technique （-0.2%）.

关键词： temporal changes remote triggering seismic noise cross-correlation interferometry seismic coda

Terahertz atmospheric windows for high angular resolution terahertz astronomy from Dome A

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Advances in Polar Science 2019年第1期30卷 76-80页

作者： Hiroshi MATSUO Shengcai SHI Scott PAINE Qijun YAO Zhenhui LIN National Astronomical Observatory of Japan Purple Mountain Observatory Key Laboratory of Radio Astronomy Chinese Academy of Sciences Smithsonian Astrophysical Observatory

Atmospheric transmission from Dome A, Antarctica, presents new possibilities in the field of terahertz astronomy, where space telescopes have been the only observational tools until now. Using atmospheric transmission measurements from Dome A with a Fourier transform spectrometer, transmission spectra and long-term stabilities have been analyzed at 1.461 THz, 3.393 THz, 5.786 THz and 7.1 THz, which show that important atmospheric windows for terahertz astronomy open for a reasonable length of time in the winter season. With large aperture terahertz telescopes and interferometers at Dome A, high angular resolution terahertz observations are foreseen of atomic fine-structure lines from ionized gas and a water ice feature from protoplanetary disks.

关键词： terahertz astronomy atmospheric window Fourier transform spectroscopy terahertz telescope terahertz interferometry

Contributions of holography to the advancement of interferometric measurements of surface topography

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Light(Advanced Manufacturing) 2022年第2期3卷 80-99页

作者： Peter J.de Groot Leslie L.Deck Rong Su Wolfgang Osten Zygo Corporation MiddlefieldCT USA Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghaiChina University of Stuttgart StuttgartGermany

Two major fields of study in optics—holography and interferometry—have developed at times independently and at other times *** two methods share the principle of holistically recording as an intensity pattern the magnitude and phase distribution of a light wave,but they can differ significantly in how these recordings are formed and *** we review seven specific developments,ranging from data acquisition to fundamental imaging theory in three dimensions,that illustrate the synergistic developments of holography and interferometry.A clear trend emerges,of increasing reliance of these two fields on a common trajectory of enhancements and improvements.

关键词： holography topography interferometry metrology