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Saturation Estimation with Complex Electrical Conductivity for Hydrate-Bearing Clayey Sediments:An Experimental Study

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Journal of Ocean University of China 2024年第1期23卷 173-189页

作者： XING Lanchang ZHANG Shuli ZHANG Huanhuan WU Chenyutong WANG Bin LAO Liyun WEI Wei HAN Weifeng WEI Zhoutuo GE Xinmin DENG Shaogui College of Control Science and Engineering China University of Petroleum(East China)Qingdao 266580China School of Water Energy and EnvironmentCranfield UniversityCranfield MK430ALUnited Kingdom Department of Alternative Energy PetroChina Research Institute of Petroleum Exploration&DevelopmentLangfang 065007China 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

Clays have considerable influence on the electrical properties of hydrate-bearing sediments.It is desirable to understand the electrical properties of hydrate-bearing clayey sediments and to build hydrate saturation(S_(h))models for reservoir evaluation and monitoring.The electrical properties of tetrahydrofuran-hydrate-bearing sediments with montmorillonite are characterized by complex conductivity at frequencies from 0.01 Hz to 1 kHz.The effects of clay and Sh on the complex conductivity were analyzed.A decrease and increase in electrical conductance result from the clay-swelling-induced blockage and ion migration in the electrical double layer(EDL),respectively.The quadrature conductivity increases with the clay content up to 10%because of the increased surface site density of counterions in EDL.Both the in-phase conductivity and quadrature conductivity decrease consistently with increasing Sh from 0.50 to 0.90.Three sets of models for Sh evaluation were developed.The model based on the Simandoux equation outperforms Archie’s formula,with a root-mean-square error(E_(RMS))of 1.8%and 3.9%,respectively,highlighting the clay effects on the in-phase conductivity.The fre-quency effect correlations based on in-phase and quadrature conductivities exhibit inferior performance(E_(RMS)=11.6%and 13.2%,re-spectively)due to the challenge of choosing an appropriate pair of frequencies and intrinsic uncertainties from two measurements.The second-order Cole-Cole formula can be used to fit the complex-conductivity spectra.One pair of inverted Cole-Cole parameters,i.e.,characteristic time and chargeability,is employed to predict S_(h) with an E_(RMS) of 5.05%and 9.05%,respectively.

关键词： gas hydrate complex electrical conductivity hydrate-bearing clayey sediment hydrate saturation Simandoux equation frequency dispersion Cole-Cole formula

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frequency dispersion effect and parameters extraction method for novel HfO2 as gate dielectric

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Science China(Information Sciences) 2010年第4期53卷 878-884页

作者： ZHAO Aaron TALLAVARJULA Sai Applied Materials Inc Sunnyvale CA 94086USA

The electric characteristic of MOS capacitor with HfO2/SiO2/p-Si grown by ALCVD （atom layer chemical vapor deposition） is investigated. The C-V curves show that the accumulation capacitances take on the frequency dispersion at high frequency. For MOS capacitor with ultra thin HfO2/SiO2gate stack, different fabrication processes and measurement equipment will cause parasitic effect. Here an equivalent circuit model that can eliminate the frequency dispersion effect is proposed. The C-V characteristics curve at high frequency shows some distortion because of the bulk defects and the interface states. This paper discusses the distortion of the high frequency MOS C-V characteristic curve. A data processing method is advanced and interface trap density distribution in the band gap is presented. By comparing the ideal C-V curve with the experimental C-V curve, the typical electrical parameters of MOS capacitor are extracted, including the shift of flat-band voltage, the oxide charges and the density of interface traps at the SiO2/Si interface.

关键词： high k gate dielectric HfO2 frequency dispersion equivalent circuit model two-frequency C-V measurement parameters extraction

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Wentzel-Kramer-Brillouin and finite-difierence time-domain analysis of Terahertz band electromagnetic characteristics of target coated with unmagnetized plasma

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Journal of Systems Engineering and Electronics 2008年第1期19卷 15-20页

作者： Liu Shaobin Zhou Tao Liu Meilin Hong Wei State Key Lab. of Millimeter Waves Southeast Univ. Nanjing 210096 P. R. China Coll. of Information Science &: Technology Nanjing Univ. of Aeronautics & Astronautics Nanjing 210016 P. R. China

We investigate computationally the attenuation and reflection of Terahertz （THz） wave using targets coated with plasmas. The simulators are the Wentzel-Kramer-Brillouin （WKB） method and finite-difference timedomain （FDTD） method. The relation between the frequency of the incident electromagnetic （EM） wave and the attenuation caused by unmagnitized plasma is analyzed. The results demonstrate that the amount of absorbed power is a decreasing function of the EM wave frequency and the plasma collision frequency. For THz band incident wave, the attenuation that is caused by plasma is small when the plasma has common density and the collision frequency. This conclusion has fine applying foreground for plasma anti stealth.

关键词： frequency dispersion WKB method FDTD methods unmagnetized plasma Terahertz wave

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Radar cross section of arbitrary polished spheres at terahertz frequencies

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Journal of Systems Engineering and Electronics 2017年第6期28卷 1072-1077页

作者： Ruijun Wang Bin Deng Hongqiang Wang Yuliang Qin College of Electronic Science and Engineering National University of Defense TechnologyChangsha 410073China Uint 95876 of PLA Zhangye 734100China

We develop an efficient method for polished metallic sphere’s scattering prediction in terahertz band when its frequency dispersion property is considered. By deducing scattering solution of the lossy metallic sphere, the radar cross section(RCS)of different metallic spheres is given at terahertz frequencies. The investigation of the RCS of polished metallic spheres shows the normalized RCS is always same to the metals’ normal incidence reflectivity when the sphere becomes electrically large. The metals which have high reflectivity(such as Al, Cu, Ag and Au) show that the corresponding RCS of the spheres is almost πa2 in terahertz band. The sphere’s RCS of the transition metal such as Fe begins to decrease obviously since the far infrared.

关键词： terahertz radar cross section(RCS) sphere Drude model frequency dispersion

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The sound velocity and bulk properties of sediments in the Bohai Sea and the Yellow Sea of China

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Acta Oceanologica Sinica 2016年第7期35卷 76-86页

作者： ZHENG Jiewen LIU Baohua KAN guangming LI Guanbao PEI Yanliang LIU Xiaolei Key Laboratory of Marine Sedimentology and Environmental Geology of State Oceanic Administration State Oceanic Administration Qingdao 266061 China First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Qingdao National Laboratory for Marine Science and Technology Qingdao 266237 China National Deep Sea Center State Oceanic Administration Qingdao 266237 China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of China Qingdao 266100 China

In order to investigate the correlation between a sound velocity and sediment bulk properties and explore the influence of frequency dependence of the sound velocity on the prediction of the sediment properties by the sound velocity, a compressional wave velocity is measured at frequencies of 25-250 kHz on marine sediment samples collected from the Bohai Sea and the Yellow Sea in laboratory, together with the geotechnical parameters of sediments. The results indicate that the sound velocity ranges from 1.232 to 1.721 km/s for the collected sediment samples with a significant dispersion within the series measuring frequency. Poorly sorted sediments are highly dispersive nearly with a positive linear relationship. The porosity shows a better negative logarithmic correlation with the sound velocity compared with other geotechnical parameters. Generally, the sound velocity increases with the increasing of the average particle size, sand content, wet and dry bulk densities, and decreasing of the clay content, and water content. An important point should be demonstrated that the higher correlation can be obtained when the measuring frequency is low within the frequency ranges from 25 to 250 kHz since the inhomogeneity of sediment properties has a more remarkably influence on the laboratory sound velocity measurement at the high frequency.

关键词： sound velocity particle composition physical properties frequency dispersion empirical equation

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Numerical Model of Internal Solitary Wave Evolution on ImpermeableVariable Seabed in A Stratified Two-Layer Fluid System

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China Ocean Engineering 2006年第2期20卷 303-313页

作者： Chen-Yuan CHEN John Rong-Chung HSU Cheng-Wu CHEN Ming-Hung CHENG Department of Madne Envirorunent and Engineering National Sun Yat-sen University Kaohsiung 80424 Taiwan China School of Civil and Resource Engineering University of Western Australia WA 6009 Australia Department of Logistics Management Shu-Te University Kaohsiung 82445 Taiwan China

In the present study a numerical model developed by Lynett and Liu （2002） is modified to include density difference in a stratified two-layer fluid in a three-dimensional internal wave domain. The internal solitary wave （ISW） in the model is assumed to be weakly nonlinear and weakly dispersive, and the viscosity effects at all boundaries are ignored. The governing equations based on the Navier-Stokes and Euler equations are solved for internal solitary wave propagation over variable seabed topography. Theoretical formulations are established, from which analytical solutions are obtained, in addition to numerical results. Wave profiles from previous experimental studies are compared with the numerical results from the present analytical solutions. Numerical models developed on the basis of the present analytical solutions are better than those developed by Lynett and Liu （2002）. The results of numerical modeling agree well with the experimental data.

关键词： Navier-Stokes equation nonlinearity frequency dispersion internal solitary wave numerical model

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Nonlinear Terahertz Electromagnetic Waves in SrTiO₃ Crystals under Focusing

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Journal of Electromagnetic Analysis and Applications 2016年第10期8卷 226-239页

作者： Volodymyr Grimalsky Svetlana Koshevaya Jesus Escobedo-Alatorre Margarita Tecpoyotl-Torres CIICAp Autonomous University of State Morelos (UAEM) Cuernavaca Mexico

The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO3 at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO3 crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO3 when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.

关键词： THz Waves SrTiO3 Paraelectric Nonlinearity frequency dispersion Focusing Modulation Instability Generation of Harmonics

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Damage detection on PVC pipes using ultrasonic longitudinal guided waves

Damage detection on PVC pipes using ultrasonic longitudinal ...

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2011年全国压电和声波理论及器件应用研讨会

作者： Zhen-hua SONG~1 Kai-hui ZhONG~1 Hong-wei MA~(1,2,*) 1 College of Science and Engineering,Jinan University,Guangzhou,China 510632 2 The Key Laboratory of Disaster Forecast and Control in Engineering,Guangzhou,China 510632

＜正＞A majority of surficial pipeline have been made of PVC materials as a result of the corruptibility,the high cost and the heavy quality of steel materials.However,the rigidity and the intensity of PVC materials are much worse than traditional materials.This kind of pipelines is damaged and cause accidents easily so that the damage detection for

关键词： Pipe PVC frequency dispersion Damage detection

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