In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative an...In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient （RAC） of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.展开更多
Synthetic Aperture Radar Interferometry(InSAR)has shown its potential on seismic deformation monitoring since it can achieve the accuracy of centimeter level or even the millimeter level.However,the irregular varietie...Synthetic Aperture Radar Interferometry(InSAR)has shown its potential on seismic deformation monitoring since it can achieve the accuracy of centimeter level or even the millimeter level.However,the irregular varieties of ionosphere can induce the additional phase delay on SAR interferometry,restricting its further application in high-precision deformation monitoring.Although several methods have been proposed to correct the ionospheric phase delay on SAR interferometry,the performances of them haven't been evaluated and compared.In this study,three commonly used methods,including polynomial fitting,azimuth offset and split-spectrum are applied to L'Aquila Earthquake to correct the ionospheric phase delay on two Phased Array type L-band Synthetic Aperture Radar(PALSAR)onboard the Advanced Land Observing Satellite-1(ALOS-1)images.The result indicates that these three methods can effectively correct the ionospheric phase delay error for SAR interferometry,where the standard deviations of the ionosphere-corrected results have decreased by almost a factor of 1.8 times for polynomial fitting method,4.2 times for azimuth offset method and 2.5 times for split-spectrum method,compared to those of the original phase.Furthermore,the result of the sliding distribution inversion of the seismic fault shows the best performance for split-spectrum method.展开更多
A hybrid method is established by combining photoelastic experiment and finite element analysis.The method is used to evaluate contact stress distribution on dry friction interfaces,such as the contact interfaces betw...A hybrid method is established by combining photoelastic experiment and finite element analysis.The method is used to evaluate contact stress distribution on dry friction interfaces,such as the contact interfaces between shrouds of fan blades and turbine blades.The photoelastic stress frozen experiment method is used to decide the displacement boundary conditions of numerical calculation.Higher accuracy and efficiency of solving problems are improved by the method.Technical difficulty and high cost of experiment are also avoided by the method.Good agreement of the stress distribution by using the hybrid method and experiment is obtained.展开更多
In this paper, we propose an instantaneous phase-stepping method for determining phase distribution of interference fringes utilizing a camera that is equipped with a micro-polarizer array on the sensor plane. An opti...In this paper, we propose an instantaneous phase-stepping method for determining phase distribution of interference fringes utilizing a camera that is equipped with a micro-polarizer array on the sensor plane. An optical setup of polarization interferometry using a Mach-Zehnder interferometer with two polarizers is constructed. Light emerging from the interferometer is recorded using a camera that has a micro-polarizer array. This micro-polarizer array has four different optical axes. That is, an image obtained by the camera contains four types of information corresponding to four different optical axes of the polarizer. The four images separated from the image recorded by the camera are reconstructed using gray level interpolation. Subsequently, the distributions of the Stokes parameters that represent the state of polarization are calculated from the four images. The phase distribution of the interference fringe pattern produced by the Mach-Zehnder interferometer is then obtained from these Stokes parameters, The effectiveness of the proposed method is demonstrated by measuring a static carrier pattern and time-variant fringe patterns. It is emphasized that this method is applicable to time-variant phenomena because multiple exposures are unnecessary for sufficient data acquisition in the completion of the phase analysis.展开更多
Thermal barrier coatings (TBCs) are widely applied in thermal components to protect metallic components. Owing to the complex layered structure of TBCs and difficult preparation of coating, the mechanical characteriza...Thermal barrier coatings (TBCs) are widely applied in thermal components to protect metallic components. Owing to the complex layered structure of TBCs and difficult preparation of coating, the mechanical characterization of TBCs should be of primary importance. With regard to TBCs, this study deals with the constitutive parameters identification of bi-material. Considering the complex construction and boundary of bi material, the virtual fields method (VFM) was employed in this study. A methodology based on the optimized virtual fields method combined with moire interferometry was proposed for the constitutive parameters identification of bi-material. The feasibility of this method is verified using simulated deformation fields of a two-layer material subjected to three point ben ding loading. As an application, the deformation fields of the TBC specimens were measured by moire interferometry. Then, lhe mechanical parameters of the coating were identified by the proposed method. The identification results indicate that Young's modulus of the TBC top coating is 89.91 GPa, and its Poisson's ratio is 0.23.展开更多
The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is pe...The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noisecompensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.展开更多
Speckle interferometry is an efficient method to analyze a vibration. In certain conditions, this technique has some outstanding advantage, and need not strict shock--proof condition, compared with the holographic met...Speckle interferometry is an efficient method to analyze a vibration. In certain conditions, this technique has some outstanding advantage, and need not strict shock--proof condition, compared with the holographic method for measuring vibration. Therefore,it is suitable to analyze a vibration with a large amplitude.Real-time interferometry is a rapid and simple method for measuring vibration of a body, gives speckle pattern containing amplitude distribution of body-surface. By means of time-averaged method, the speckle pattern is recorded in Fourier transform plane, or vibration lines are seen directly with eyes, so as to analyze efficiently amplitude, phase, and model of a vibration. This paper deduces the intensity distribution function with real-time method, and gives experimental demonstration of vibration body-the vibration lines with different frequencies.展开更多
基金supported by the national project"Deep Exploration Technology and Experimentation"(SinoProbe-09-02)
文摘In order to suppress the airwave noise in marine controlled-source electromagnetic （CSEM） data, we propose a 3D deconvolution （3DD） interferometry method with a synthetic aperture source and obtain the relative anomaly coefficient （RAC） of the EM field reflection responses to show the degree for suppressing the airwave. We analyze the potential of the proposed method for suppressing the airwave, and compare the proposed method with traditional methods in their effectiveness. A method to select synthetic source length is derived and the effect of the water depth on RAC is examined via numerical simulations. The results suggest that 3DD interferometry method with a synthetic source can effectively suppress the airwave and enhance the potential of marine CSEM to hydrocarbon exploration.
基金National Science Foundation of China(Nos.42074040,41941019,41790445)National Key R&D Program of China(Nos.2020YFC1512001,2019YFC1509800)Shenzhen Science and Technology Program(No.KQTD20180410161218820)。
文摘Synthetic Aperture Radar Interferometry(InSAR)has shown its potential on seismic deformation monitoring since it can achieve the accuracy of centimeter level or even the millimeter level.However,the irregular varieties of ionosphere can induce the additional phase delay on SAR interferometry,restricting its further application in high-precision deformation monitoring.Although several methods have been proposed to correct the ionospheric phase delay on SAR interferometry,the performances of them haven't been evaluated and compared.In this study,three commonly used methods,including polynomial fitting,azimuth offset and split-spectrum are applied to L'Aquila Earthquake to correct the ionospheric phase delay on two Phased Array type L-band Synthetic Aperture Radar(PALSAR)onboard the Advanced Land Observing Satellite-1(ALOS-1)images.The result indicates that these three methods can effectively correct the ionospheric phase delay error for SAR interferometry,where the standard deviations of the ionosphere-corrected results have decreased by almost a factor of 1.8 times for polynomial fitting method,4.2 times for azimuth offset method and 2.5 times for split-spectrum method,compared to those of the original phase.Furthermore,the result of the sliding distribution inversion of the seismic fault shows the best performance for split-spectrum method.
基金Youth Foundation of Beijing Polytechnic University
文摘A hybrid method is established by combining photoelastic experiment and finite element analysis.The method is used to evaluate contact stress distribution on dry friction interfaces,such as the contact interfaces between shrouds of fan blades and turbine blades.The photoelastic stress frozen experiment method is used to decide the displacement boundary conditions of numerical calculation.Higher accuracy and efficiency of solving problems are improved by the method.Technical difficulty and high cost of experiment are also avoided by the method.Good agreement of the stress distribution by using the hybrid method and experiment is obtained.
文摘In this paper, we propose an instantaneous phase-stepping method for determining phase distribution of interference fringes utilizing a camera that is equipped with a micro-polarizer array on the sensor plane. An optical setup of polarization interferometry using a Mach-Zehnder interferometer with two polarizers is constructed. Light emerging from the interferometer is recorded using a camera that has a micro-polarizer array. This micro-polarizer array has four different optical axes. That is, an image obtained by the camera contains four types of information corresponding to four different optical axes of the polarizer. The four images separated from the image recorded by the camera are reconstructed using gray level interpolation. Subsequently, the distributions of the Stokes parameters that represent the state of polarization are calculated from the four images. The phase distribution of the interference fringe pattern produced by the Mach-Zehnder interferometer is then obtained from these Stokes parameters, The effectiveness of the proposed method is demonstrated by measuring a static carrier pattern and time-variant fringe patterns. It is emphasized that this method is applicable to time-variant phenomena because multiple exposures are unnecessary for sufficient data acquisition in the completion of the phase analysis.
基金the NationalKey Research and Development Procedure of China (Grant 2017YFB1103900)National Natural Science Foundation of China (Grants 11672153.11232008, 11227801).
文摘Thermal barrier coatings (TBCs) are widely applied in thermal components to protect metallic components. Owing to the complex layered structure of TBCs and difficult preparation of coating, the mechanical characterization of TBCs should be of primary importance. With regard to TBCs, this study deals with the constitutive parameters identification of bi-material. Considering the complex construction and boundary of bi material, the virtual fields method (VFM) was employed in this study. A methodology based on the optimized virtual fields method combined with moire interferometry was proposed for the constitutive parameters identification of bi-material. The feasibility of this method is verified using simulated deformation fields of a two-layer material subjected to three point ben ding loading. As an application, the deformation fields of the TBC specimens were measured by moire interferometry. Then, lhe mechanical parameters of the coating were identified by the proposed method. The identification results indicate that Young's modulus of the TBC top coating is 89.91 GPa, and its Poisson's ratio is 0.23.
文摘The paper presents a number of signal processing approaches for the spectral interferometric interrogation of extrinsic Fabry-Perot interferometers(EFPIs). The analysis of attainable microdisplacement resolution is performed and the analytical equations describing the dependence of resolution on parameters of the interrogation setup are derived. The efficiency of the proposed signal processing approaches and the validity of analytical derivations are supported by experiments. The proposed approaches allow the interrogation of up to four multiplexed sensors with attained resolution between 30 pm and 80 pm, up to three times improvement of microdisplacement resolution of a single sensor by means of using the reference interferometer and noisecompensating approach, and ability to register signals with frequencies up to 1 kHz in the case of 1 Hz spectrum acquisition rate. The proposed approaches can be used for various applications, including biomedical, industrial inspection, and others, amongst the microdisplacement measurement.
文摘Speckle interferometry is an efficient method to analyze a vibration. In certain conditions, this technique has some outstanding advantage, and need not strict shock--proof condition, compared with the holographic method for measuring vibration. Therefore,it is suitable to analyze a vibration with a large amplitude.Real-time interferometry is a rapid and simple method for measuring vibration of a body, gives speckle pattern containing amplitude distribution of body-surface. By means of time-averaged method, the speckle pattern is recorded in Fourier transform plane, or vibration lines are seen directly with eyes, so as to analyze efficiently amplitude, phase, and model of a vibration. This paper deduces the intensity distribution function with real-time method, and gives experimental demonstration of vibration body-the vibration lines with different frequencies.
