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Joint inversion method for interval quality factor based on amplitude and phase information

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Applied Geophysics 2019年第2期16卷 199-208,253-254页

作者： Cao Dan-Ping Li Yue Sun Wen-Guo Liang Kai School of Geosciences China University of Petroleum (East China)Qingdao 266580China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China.

Estimating the quality factor Q accurately signifi cantly improves the seismic data resolution and reservoir *** commonly used log-spectral ratio method uses least-squares fi tting to obtain Q values and involves only the amplitude information of seismic data while neglecting phase *** paper proposes a joint interval Q inversion method based on the spectral ratio method and employs both amplitude and phase information to improve the *** on the assumption that Q is independent of frequency,the nonlinear relation between the Q value and the two types of information is jointly used to construct an objective function,which clarifies the quantitative relation between amplitude spectrum,phase information,and Q *** interval Q value can be inverted by calculating the minimum value of the objective *** model test exhibits that the proposed method has higher precision and stability than the spectral ratio method;furthermore,the application to field data demonstrates that accurate Q inversion results are consistent with reservoir characteristics.

关键词： viscoelastic medium quality factor amplitude phase

Comparison of Free Spectral Range and quality factor for Two-Dimensional Square and Circular Microcavities

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Chinese Physics Letters 2004年第1期21卷 79-80页

作者：国伟华黄永箴陆巧银于丽娟 StateKeyLaboratoryofIntegratedOptoelectronics InstituteofSemiconductorsChineseAcademyofSciencesPOBox912Beijing100083

Free spectral range of whispering-gallery (WG)-like modes in a two-dimensional (2D) square microcavity is found to be wtwice that in a 2D circular microcavity. The quality factor of the WG-like mode with the low mode number in a 2D square microcavity, calculated by the finite-difference time-domain (FDTD) technique and the Pade approximation method, is found to exceed that of the WG mode in 2D circular microcavity with the same cavity dimension and close mode wavelength.

关键词： cavity dimension circular spectral region quality factor Approximation method microcavities

Revisiting the period and quality factor of the Chandler wobble and its possible geomagnetic jerk excitation

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Geodesy and Geodynamics 2022年第5期13卷 427-434页

作者： Yachong An Hao Ding Department of Geophysics School of Geodesy and GeomaticsKey Laboratory of Geospace Environment and Geodesy of the Ministry of EducationWuhan University430079 WuhanChina Hubei Luo Jia Laboratory 430079 WuhanChina

The period and quality factor of the Chandler wobble(CW)are useful for constraining the Earth’s internal structure properties,such as the mantle *** has been shown that the CW is mainly excited by a combination of atmospheric and oceanic processes;hence based on a deconvolution method,we can remove them from the excitation sequence of the CW to estimate its period P and quality factor *** finally re-estimate P=432.3±0.8 days and Q=85±15 for the *** on those two estimates,we investigate the relationship between the geomagnetic jerks and the excitation sequences of the *** geomagnetic jerks or jerk bounds are well consistent with the sudden changes of the excitation sequences of the *** demonstrates that the geomagnetic jerks could be a possible excitation source of the *** is crucial for understanding the excitation of the CW and for deeper geophysical insights into the geomagnetic jerks.

关键词： Chandler wobble quality factor De-convolution Geomagnetic jerks

Investigation of quality factor frequency content in vertical seismic profile for gas reservoirs

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Petroleum Research 2021年第1期6卷 57-65页

作者： Ehsan Larki Abbas Ayatizadeh Tanha Amirhossein Parizad Bahram Soltani Soulgani Dr Hassan Bagheri National Iranian Drilling Company Well Logging DepartmentAhwazIran Petroleum University of Technology Ahwaz Faculty of Petroleum EngineeringAhwazIran Sahand University of Technology Petroleum Exploration EngineeringTabrizIran Department of Petroleum Engineering Ahwaz Faculty of Petroleum EngineeringPetroleum University of Technology(PUT)AhwazIran

Since long ago, indirect study of the underground layers properties has been interesting to *** method for this study was seismography which gained great interest besides other tools due to thedifferent identity of waves and energy attraction phenomena in different layers. Vertical seismic profiling(VSP) is considered as a valuable method in oil and gas exploration. This method is used to estimate therock properties in a well. In seismic operations elastic waves are sent down to the underground. Part ofthe waves’ energy is reflected after passing through the earth layers and are received by receivers on theground level. The received data determine the situation of the underneath layers after being processed,and one of the most important applications of seismic data is in the oil and gas exploration field. qualityfactor is one of the most important seismic detectors that shows itself apparently in VSP data results. Themost substantial purpose of this study is to investigate the frequency content of the quality factor.

关键词： Vertical seismic profiling(VSP) Sonic log Seismic waves quality factor Rock properties Gas reservoir

Novel S-slot DGS with high quality factor

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Journal of Southeast University(English Edition) 2009年第4期25卷 431-434页

作者：朱轶智张晓娟方广有中国科学院电子学研究所北京100190 中国科学院研究生院北京100049

In order to solve the problem that the quality factor （ Q factor） of the conventional defected ground structure （DGS）is not high and cannot produce a sharp resonant band, a novel S-slot DGS is presented. Compared with the conventional DGS, the proposed S-slot DGS has a much higher Q factor, a quite simpler layout and a steeper band rejection. Its equivalent circuit model is extracted by analyzing the transfer characteristics, and design parameters are calculated according to the deducted equations. Characteristics of this type of DGS are investigated with variable dimension parameters and an experiential method for the design of the S-slot DGS is summarized. Finally, a sample of a compact S-slot DGS unit resonated at 4. 64 GHz is fabricated. Its Q factor is as high as 39. 66 and its size is only 5.00 mm × 1.40 mm, with a steep resonant band and a low insertion-loss passband. The measured results show a good agreement with simulation, which demonstrates the applicability of the S-slot DGS in practical engineering.

关键词： S-slot defected ground structure (DGS) quality factor

Twisted lattice nanocavity with theoretical quality factor exceeding 200 billion

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Fundamental Research 2023年第4期3卷 537-543页

作者： Ren-Min Ma Hong-Yi Luan Zi-Wei Zhao Wen-Zhi Mao Shao-Lei Wang Yun-Hao Ouyang Zeng-Kai Shao State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010JiangsuChina National Biomedical Imaging Center Peking UniversityBeijing 100871China

Simultaneous localization of light to extreme spatial and spectral scales is of high importance for testing fundamental physics and various ***,there is a longstanding trade-off between localizing a light field in space and in *** we discover a new class of twisted lattice nanocavities based on mode locking in momentum *** twisted lattice nanocavity hosts a strongly localized light field in a 0.048𝜆3 mode volume with a quality factor exceeding 2.9×1011(∼250𝜇s photon lifetime),which presents a record high figure of merit of light localization among all reported optical *** on the discovery,we have demonstrated silicon-based twisted lattice nanocavities with quality factor over 1 *** result provides a powerful platform to study light-matter interaction in extreme conditions for tests of fundamental physics and applications in nanolasing,ultrasensing,nonlinear optics,optomechanics and quantum-optical devices.

关键词： Nanocavities Twisted lattice quality factor Mode volume Flatband Mode coupling

Influence of the quality factor on simulated seismic waves:A case study of the 1994 Northridge earthquake

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Earthquake Science 2022年第5期35卷 329-342页

作者： Qingpei Zeng Xiangchao Wang Jinting Wang Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China

In numerical simulations of ground motion,the constant quality factor Q of a viscoelastic medium can be determined using the time-domain constitutive approximation method of the generalized standard linear solid(GSLS)*** study introduces a numerical seismic wavefield simulation method which combines the spectral element method with the constant-Q *** method is used to simulate the seismic wavefield of the 1994 Northridge *** optimal attenuation coefficient for the simulated seismic waves in this study area is determined empirically based on a quantitative analysis of the deviation ***,the effect of the quality factor on the simulated wavefield are analyzed according to the site characteristics of each seismic *** quality factor shows a variable effect on the different frequency components of the simulated *** effect of the quality factor also varies with the characteristic parameters of each seismic station site,such as site velocity structure,fault distance,and azimuth angle.

关键词： ground motion simulation quality factor viscoelasticity SLS spectral element method

Discussion on the Measurement Method for the Coda Wave quality factor

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Earthquake Research in China 2009年第4期23卷 420-433页

作者： Liu Xiqiang Shi Yuyan Qu Junhao Li Hong Li Bo Zhang Kun Earthquake Administration of Shandong Province Jinan 250014 China

The quality factor is the parameter that can be used to describe the energy attenuation on seismic wave. In theory, we can obtain the relationship between the change of the coda wave quality factor with time and the strong earthquake preparation process on the basis of the quality factor of a coda wave in a same ray path. However, in reality the coda wave quality factor measured by different seismic coda waves corresponds to different seismic wave ray paths. The change of the quality factor with time is related to non-elastic characteristics of the medium and the volume of scattering ellipsoid constrained by scattered wave phase fronts, besides the change of regional stress field. This paper discusses the relationship between quality factor, epicenter distance and different lapse time, and then discusses the relationship between quality factor and frequency. Furthermore the determination method of the coda wave quality factor is put forward. The improved determination method of the quality factor, which removes the influence of different earthquakes or propagation depth of scattered waves, may increase measurement precision, thus information pertaining to abnormal changes in quality factor and the relationship between the quality factor and earthquake preparation process can be acquired.

关键词： quality factor Coda wave Measurement method Discussion Application

Improved Design and Modeling of Micromachined Tuning Fork Gyroscope Characterized by High quality factor

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Journal of Electronic Science and Technology 2010年第3期8卷 280-286页

作者： Ji-Ping Guan Xiao-Ming Liu with School of Mechatronics Engineering University of Electronic Science and Technology of China Chengdu 610054 China

This paper proposes an improved design of micromachined tuning fork gyroscope （M-TFG） to decouple the cross talk between driving and sensing directions better and to increase resolution. By employing dual-folds spring suspension, the drive mode and the sense mode are mechanically decoupled. Through careful layout design of the location of the dual-folds spring suspension and the drive combs, the mechanical coupling effect is further decreased by isolating the unwanted excitation from detection. The quality factor investigation demonstrates that high quality factor can be attained by using this structure, which can bring in accurate resolution. As a result, this design has the potential to accomplish low bias drift and accurate resolution for initial level applications.

关键词： Decouple gyroscope micromachined quality factor tuning fork.