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An eikonal equation-based earthquake location method by inversion of multiple phase arrivals

Science China Earth Sciences 2024年第6期67卷 1802-1817页

作者： Gaoyue LAO Dinghui YANG Shaolin LIU Guiju DONG Wenshuai WANG Kui LIU National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China School of Earth Sciences Yunnan UniversityKunming 650091China Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China

The precise determination of earthquake location is the fundamental basis in seismological community,and is crucial for analyzing seismic activity and performing seismic *** arrivals are generally used to practically determine earthquake ***,first-arrival traveltimes are not sensitive to focal ***,they cannot accurately constrain focal *** improve the accuracy,researchers have analyzed the depth phases of earthquake *** traveltimes of depth phases are sensitive to focal depths,and the joint inversion of depth phases and direct phases can be implemented to potentially obtain accurate earthquake ***,researchers can determine earthquake locations in layered *** layered models can only represent the first-order feature of subsurface structures,the advantages of joint inversion are not fully explored if layered models are *** resolve the issue of current joint inversions,we use the traveltimes of three seismic phases to determine earthquake locations in heterogeneous *** three seismic phases used in this study are the first P-,sPg-and *** calculate the traveltimes of the three seismic phases by solving an eikonal equation with an upwind difference scheme and use the traveltimes to determine earthquake *** verify the accuracy of the earthquake location method by the inversion of three seismic phases,we take the 2021 M_(S)6.4 Yangbi,Yunnan earthquake as an example and locate this earthquake using synthetic and real seismic *** tests demonstrate that the eikonal equation-based earthquake location method,which involves the inversion of multiple phase arrivals,can effectively improve earthquake location accuracy.

关键词： Earthquake location Eikonal equation Fast marching method heterogeneous model

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Damage Evolution and Crack Propagation in Semicircular Bending Asphalt Mixture Specimens

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Acta Mechanica Solida Sinica 2016年第6期29卷 596-609页

作者： Guowei Zeng Xinhua Yang Long Chen Fan Bai School of Civil Engineering and Mechanics Huazhong University of Science and Technology School of Science Wuhan University of Science and Technology

The damage and fracture behaviors of semicircular bending （SCB） asphalt mixture specimens with different orientation notches are experimentally and numerically investigated. In the numerical simulations, asphalt mixture is modeled as a two-phase material, namely a mix of coarse aggregates and asphalt mastic, and the mechanical behavior of asphalt mastic is charac- terized with the damage constitutive model and the damage-based fracture criterion. Some SCB experiments are performed on the asphalt mixture specimens with different orientation notches to validate the numerical method. Finally, the effects of notch orientation and aggregate distrib- ution on crack path, damage distribution, and the load vs. displacement relation are numerically evaluated.

关键词： semicircular bending heterogeneous model damage notch orientation

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Dynamic modeling of a H_2O-permselective membrane reactor to enhance methanol synthesis from syngas considering catalyst deactivation

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Journal of Natural Gas Chemistry 2012年第4期21卷 407-414页

作者： M.Farsi A.Jahanmiri Department of Chemical Engineering School of Chemical and Petroleum EngineeringShiraz UniversityShiraz 71345Iran

In this paper, the effect of water vapor removal on methanol synthesis capacity from syngas in a fixed-bed membrane reactor is studied considering long-term catalyst deactivation. A dynamic heterogeneous one-dimensional mathematical model that is composed of two sides is developed to predict the performance of this configuration. In this configuration, conventional methanol reactor is supported by an aluminasilica composite membrane layer for water vapor removal from reaction zone. To verify the accuracy of the considered model and assumptions, simulation results of the conventional methanol reactor is compared with the industrial plant data under the same process condition. The membrane reactor improves catalyst life time and enhances CO2 conversion to methanol by overcoming the limitation imposed by thermodynamic equilibrium. This configuration has enhanced the methanol production capacity about 4.06% compared with the industrial methanol reactor during the production time.

关键词： membrane reactor heterogeneous model dynamic simulation composite membrane

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Upgrading Siberian(Russia) crude oil by hydrodesulfurization: Kinetic parameter estimation in a trickle-bed reactor

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Chinese Journal of Chemical Engineering 2021年第1期34卷 212-220页

作者： Kening Sun Xixi Ma Ruijun Hou Beijing Key Laboratory for Chemical Power Source and Green Catalysis School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China

Hydrodesulfurization(HDS) of sour crude oil is an effective way to address the corrosion problems in refineries and is an economic way to process sour crude oil in an existing refinery built for sweet *** crude oil transported through the Russia-China pipeline could be greatly sweetened and could be refined directly in local refinery designed for Daqing crude oil after the effective HDS *** this study,the HDS of Siberian crude oil was carried out in a continuous flow isothermal trickle-bed reactor over Ni-Mo/γ-Al_2 O_(3).The effects of temperature,pressure and LHSV were investigated in the ranges of 320-360℃,3-5 MPa and 0.5-2 h^(-1),keeping constant hydrogen to oil ratio at 600 L·L^(-1).The HDS conversion could be up to 92.89% at the temperature of 360℃, pressure of 5 MPa,and LHSV of 0.5 h^(-1), which is sufficient for local refineries(>84%).A three phase heterogeneous model was established to analyze the performance of the trickle-bed reactor based on the two-film theory using Langmuir-Hinshelwood *** order of sulfur component is estimated as 1.28,and the order of hydrogen is *** simulating the reactor using the established model,the concentration of H_(2), H_(2) S and sulfur along the catalyst bed is *** model is significantly useful for industrial application with respect to reactor analysis,optimization and reactor design,and can provide further insight of the HDS of Siberian crude oil.

关键词： HDS Trickle-bed reactor heterogeneous model Kinetics Siberian crude oil

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Theoretical Study on Auto-Oscillating Combustion in Self-propagating High Temperature Synthesis

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Journal of Wuhan University of Technology(Materials Science) 2003年第4期18卷 32-34页

作者：张金咏 Wuhan university of Technology

Oscillating combustion is one of classic phenomenon in *** the cause of its formation in a set of complex processes is unclear *** a two-step chemical reaction assumption and effects of other thermal dynamic factors,an auto-oscillating combustion has been gained in a solid SHS process on the macro-homogenous and micro-heterogonous *** solution shows that the change of chemical reaction is the main cause of the oscillating combustion.

关键词： auto-oscillating SHS thermodynamics heterogeneous model

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modeling and Simulation of Coke Combustion Regeneration for Coked Cr2O3/Al2O3 Propane Dehydrogenation Catalyst

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Chinese Journal of Chemical Engineering 2010年第4期18卷 618-625页

作者：张新平隋志军周兴贵袁渭康 State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai 200237 China

A heterogeneous model is developed for the regeneration of the Cr2O3/Al2O3 catalyst for the propane dehydrogenation process by considering the internal mass transfer and external mass/heat transfer during the coke *** shows that under practical operating conditions,multi-steady states exist for the catalyst pellets and the catalyst temperature is sensitive to gas ***,at increased mass flow rate or lowered oxygen concentration,multi-steady states will not *** the strong influences of film diffusion,the coke in the packed bed reactor will first be exhausted at the inlet,while if the film diffusion resistance is decreased,the position of first coke exhaustion moves toward the outlet of the reactor.

关键词： propane dehydrogenation coke combustion regeneration heterogeneous model simulation

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Researches on the PAM／Cr^3＋ Gel for Deep Profile Control

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Petroleum Science 2004年第1期1卷 65-69页

作者： ChangXuejun LiuXuejun WangQunyi GaoShusheng ChinaUniversityofminingTechnology Beijing100083China InstituteofJidongOilfield TangshanHebei063004China Box44 LangFangHebei065007China

The profile control hard-gel is composed of polyarylamide (5-6g/L), whose molecular weight is 4,000,000 - 7,000,000 and hydrolysis degree is 17.6%, and cross-linking oxidation-reduction agent (Na2Cr2O7 + NH4Cl), with an delayed organic acid crosslinker which contains lactic acid/propionic acid/ethanoic acid and ethylene glycol. After research of the influence factors, such as pH, temperature, salinity and the dosage of delayed crosslinker, the optimum condition(pH 5.2, temperature 55℃, salinity heterogeneous models, which contains three serial high permeable and low permeable cores arranged in a parallel. After water flooding (total recovery, 24.3%), the first, second and third high-permeable cores each are sealed in turn by the profile control agent, and the total displacement recovery increases to 46.8%, 62.2% and 69.1% respectively. So, the greater the sealed depth, the larger the enhancing recovery will be. Finally, the oil displacement mechanisms of deep profile control are discussed.

关键词： Deep profile control hard-gel delayed cross-linker gelation time heterogeneous model sealed depth

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