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Influence of pressure disturbance wave on dynamic response characteristics of liquid film seal for multiphase pump
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作者 Qing-Ping Li Jin-Ya Zhang +1 位作者 Jia-Xiang Zhang Yong-Xue Zhang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第3期2048-2065,共18页
Slug flow or high GVF(Gas Volume Fraction)conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps,endangering the safety of multiphase pump units.... Slug flow or high GVF(Gas Volume Fraction)conditions can cause pressure disturbance waves and alternating loads at the boundary of mechanical seals for multiphase pumps,endangering the safety of multiphase pump units.The mechanical seal model is simplified by using periodic boundary conditions and numerical calculations are carried out based on the Zwart-Gerber-Belamri cavitation model.UDF(User Define Function)programs such as structural dynamics equations,alternating load equations,and pressure disturbance equations are embedded in numerical calculations,and the dynamic response characteristics of mechanical seal are studied using layered dynamic mesh technology.The results show that when the pressure disturbance occurs at the inlet,as the amplitude and period of the disturbance increase,the film thickness gradually decreases.And the fundamental reason for the hysteresis of the film thickness change is that the pressure in the high-pressure area cannot be restored in a timely manner.The maximum value of leakage and the minimum value of axial velocity are independent of the disturbance period and determined by the disturbance amplitude.The mutual interference between enhanced waves does not have a significant impact on the film thickness,while the front wave in the attenuated wave has a promoting effect on the subsequent film thickness changes,and the fluctuation of the liquid film cavitation rate and axial velocity under the attenuated wave condition deviates from the initial values.Compared with pressure disturbance conditions,alternating load conditions have a more significant impact on film thickness and leakage.During actual operation,it is necessary to avoid alternating load conditions in multiphase pump mechanical seals. 展开更多
关键词 Multiphase pump Liquid film seal Pressure disturbance wave Dynamic response characteristics
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Dynamic response characteristics of a circular lined tunnel under anisotropy frost heave of overlying soil at the tunnel portal section in cold regions
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作者 ZHANG Shuo-cheng CHEN Wen-hua 《Journal of Mountain Science》 SCIE CSCD 2023年第5期1424-1440,共17页
The rapid development of traffic engineering in cold regions and its consequent problems need to be considered.In this paper,the dynamic response characteristics of the tunnel portal section in cold regions with harmo... The rapid development of traffic engineering in cold regions and its consequent problems need to be considered.In this paper,the dynamic response characteristics of the tunnel portal section in cold regions with harmonic load acting on the lining were studied in the frequency domain.The lining is in close contact with the frozen soil,and there is relative movement between the frozen and unfrozen soil due to the phase change.The analytical solution of the vibration of tunnel portal section caused by the harmonic load acting on the lining was derived under the consideration of the anisotropy frost heave of overlying soil.Based on the continuity conditions and boundary conditions,the undetermined coefficients were obtained,and the analytical solutions for different medium displacements and stresses of the cold-region tunnel system were acquired.The vertical pressure coefficient was equivalently simplified as a variable that could be used to replace the thickness of the overlying soil above the tunnel.The analysis of the parameter model shows that the change of the medium parameters(lining,frozen,and unfrozen soil)affects the circumferential stresses,the radial displacements and their peak frequencies of the soil.For example,the increase of density ratio of tunnel lining to frozen soil decreases the radial stresses of the frozen and unfrozen soil;the increase of volumetric frost heaving strain of the frozen soil increases the radial displacements of the frozen surface and decreases the stability of the frozen surface;the increasing of thickness of the frozen soil significantly reduces the radial displacement of unfrozen soil at dimensionless radius η=4.5 compared with that of frozen soil at η=1.5. 展开更多
关键词 Frost heave Tunnel portal section Relative movement Dynamic response characteristics Cold region
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Stress response characteristics of BFRP anchors on loess mudstone slope under rainfall conditions
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作者 WEI Hong WU Hong-gang +3 位作者 WU Dao-yong TANG Lin PAI Li-fang GUAN Wei 《Journal of Mountain Science》 SCIE CSCD 2023年第5期1469-1482,共14页
To investigate the stress response characteristics and shear stress transfer mechanism of BFRP(basalt fiber reinforced plastics)anchors under rainfall conditions and to explore the reinforcement effect of BFRP anchors... To investigate the stress response characteristics and shear stress transfer mechanism of BFRP(basalt fiber reinforced plastics)anchors under rainfall conditions and to explore the reinforcement effect of BFRP anchors,a comparative indoor physical model test was conducted in this study using loess mudstone slope as a typical case,and multi-attribute response data,such as slope displacement,BFRP anchor strain and axial force,were obtained.Based on the variation law of slope displacement,it can be concluded that the deformation displacement of the slope on the side reinforced by BFRP anchors is smaller than that of slopes reinforced with steel anchors;the bearing capacity of BFRP anchor is given priority in time,and the anchoring effect of BFRP anchor at the top of the slope is given priority,and the axial force value of anchor is characterized by a surface amplification effect in space;the axial force is higher around the anchor head and tends to decay as a negative exponential function as the anchor extends in the direction of the interior of the slope;the shear stress of BFRP anchor and anchorage body are unevenly distributed along the axial direction,with the maximum value occurring in the free section near the slope surface and decreases as the BFRP anchor extends towards the interior of the slope.These results can provide a theoretical basis for the optimal design of BFRP anchors. 展开更多
关键词 BFRP Stress response characteristics Stress transfer mechanism Load transfer curve
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Analysis and application of the response characteristics of DLL and LWD resistivity in horizontal well 被引量:9
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作者 胡松 李军 +1 位作者 郭洪波 王昌学 《Applied Geophysics》 SCIE CSCD 2017年第3期351-362,459,460,共14页
There exist different response characteristics in the resistivity measurements of dual laterolog (DLL) and logging while drilling (LWD) electromagnetic wave propagation logging in highly deviated and horizontal we... There exist different response characteristics in the resistivity measurements of dual laterolog (DLL) and logging while drilling (LWD) electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method (3D-FEM) simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis. 展开更多
关键词 response characteristic dual laterolog LWD resistivity horizontal well numerical modeling
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Circuit-Level Analysis on Opto-Electronic Characteristics of Ferroelectric Liquid Crystal 被引量:1
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作者 朱思奇 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第10期1523-1526,共4页
We propose an electronic model in Spice, instead of traditional mathematical analysis, for analyzing the performance of ferroelectric liquid crystal (FLC) under various working conditions. Using this equivalent circ... We propose an electronic model in Spice, instead of traditional mathematical analysis, for analyzing the performance of ferroelectric liquid crystal (FLC) under various working conditions. Using this equivalent circuit model,it is easy to simulate and analyze the behavior of an FLC layer in three different typical parameters,including temperature, input light wavelength, and the frequency of driving voltage. We conclude that the response velocity drops as the wavelength increases in the range of visible light, and for the parameter of temperature, the velocity reaches its lowest value when the temperature reaches a certain degree,meanwhile,the frequency of driving voltage exerts important effects on the response velocity only when the frequency is beyond a critical value. Excellent agreement is achieved between simulation and experimental results. 展开更多
关键词 ferroelectric liquid crystal circuit-level analysis response characteristics typical parameters
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Research on coupled thermo-hydro-mechanical dynamic response characteristics of saturated porous deep-sea sediments under vibration of mining vehicle 被引量:1
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作者 Wei ZHU Xinyu SHI +2 位作者 Rong HUANG Liyue HUANG Wenbo MA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2021年第9期1349-1362,共14页
The excessive deformation of deep-sea sediments caused by the vibration of the mining machine will adversely affect the efficiency and safety of mining.Combined with the deep-sea environment,the coupled thermo-hydro-m... The excessive deformation of deep-sea sediments caused by the vibration of the mining machine will adversely affect the efficiency and safety of mining.Combined with the deep-sea environment,the coupled thermo-hydro-mechanical problem for saturated porous deep-sea sediments subject to the vibration of the mining vehicle is investigated.Based on the Green-Lindsay(G-L)generalized thermoelastic theory and Darcy’s law,the model of thermo-hydro-mechanical dynamic responses for saturated porous deep-sea sediments under the vibration of the mining vehicle is established.We obtain the analytical solutions of non-dimensional vertical displacement,excess pore water pressure,vertical stress,temperature,and change in the volume fraction field with the normal mode analysis method,and depict them graphically.The normal mode analysis method uses the canonical coordinate transformation to solve the equation,which can quickly decouple the equation by ignoring the modal coupling effect on the basis of the canonical mode.The results indicate that the vibration frequency has obvious influence on the vertical displacement,excess pore water pressure,vertical stress,and change in volume fraction field.The loading amplitude has a great effect on the physical quantities in the foundation,and the changes of the physical quantities increase with the increase in loading amplitude. 展开更多
关键词 deep-sea sediment thermo-hydro-mechanical dynamic generalized thermoelastic theory normal mode analysis dynamic response characteristic
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Response characteristics of sonar receiver under intense sound pulse 被引量:1
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作者 Kaizhuo Lei Qunfei Zhang Ziliang Qiao Lingling Zhang Qiang Huang Shiqing Wang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第6期843-848,共6页
For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control (AGC) circuit and the survivability of the prime circuit under strong interferenc... For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control (AGC) circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments. An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed. Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated (LFM) signal commonly used in the active sonar. Based on intense sound pulse (ISP) interference experiments, the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results. Simulation and experiment results show that, under 252 dB/20 μs ISP interference, the specific sonar receiver will produce sustained cut top oscillation above 30 ms, which may affect the receiver and block the regular sonar signal. 展开更多
关键词 sonar receiver response characteristic simulationand experiment strong interference intense sound pulse (ISP) automatic gain control (AGC).
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Photovoltaic Response Characteristics of GaAs Photoconductive Switches Under High Gain Mode 被引量:1
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作者 DAI Hui-ying SHI Wei 《Semiconductor Photonics and Technology》 CAS 2007年第4期280-282,293,共4页
Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is ... Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is an analysis of the switchs photovoltaic response characteristics under the high gain mode when the biased field is bigger than the Geng effect field. Also a theory is presented that the main reason for the photovoltaic pulse response delay is the transmission of charge domain, caused by the presence of EL2 energy level in the chip material. Finally, the transmission time of charge domain is calculated and a result that inosculates with the experiment is attained. 展开更多
关键词 photoconductive switch EL2 energy level electric charge domain photovoltaic response characteristic
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Dynamic Characteristics and Simplified Numerical Methods of An All-Vertical-Piled Wharf in Offshore Deep Water 被引量:5
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作者 张华庆 孙熙平 +2 位作者 王元战 尹纪龙 王朝阳 《China Ocean Engineering》 SCIE EI CSCD 2015年第5期705-718,共14页
There has been a growing trend in the development of offshore deep-water ports in China. For such deep sea projects, all-vertical-piled wharves are suitable structures and generally located in open waters, greatly aff... There has been a growing trend in the development of offshore deep-water ports in China. For such deep sea projects, all-vertical-piled wharves are suitable structures and generally located in open waters, greatly affected by wave action. Currently, no systematic studies or simplified numerical methods are available for deriving the dynamic characteristics and dynamic responses of all-vertical-piled wharves under wave cyclic loads. In this article, we compare the dynamic characteristics of an all-vertical-piled wharf with those of a traditional inshore high-piled wharf through numerical analysis; our research reveals that the vibration period of an all-vertical-piled wharf under cyclic loading is longer than that of an inshore high-piled wharf and is much closer to the period of the loading wave. Therefore, dynamic calculation and analysis should be conducted when designing and calculating the characteristics of an all-vertical-piled wharf. We establish a dynamic finite element model to examine the dynamic response of an all-vertical-piled wharf under wave cyclic loads and compare the results with those under wave equivalent static load; the comparison indicates that dynamic amplification of the structure is evident when the wave dynamic load effect is taken into account. Furthermore, a simplified dynamic numerical method for calculating the dynamic response of an all-vertical-piled wharf is established based on the P-Y curve. Compared with finite element analysis, the simplified method is more convenient to use and applicable to large structural deformation while considering the soil non-linearity. We confirmed that the simplified method has acceptable accuracy and can be used in engineering applications. 展开更多
关键词 offshore deep water port all-vertical-piled wharf dynamic characteristics wave cyclic loads dynamic response simplified calculating methods
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High-power microwaves response characteristics of silicon and GaAs solar cells
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作者 Xiangrui Meng Changchun Chai +2 位作者 Fuxing Li Yi Sun Yintang Yang 《Journal of Semiconductors》 EI CAS CSCD 2022年第11期54-60,共7页
The high-power microwave(HPM)effect heats solar cells,which is an important component of a satellite.This creates a serious reliability problem and affects the normal operation of a satellite.In this paper,the differe... The high-power microwave(HPM)effect heats solar cells,which is an important component of a satellite.This creates a serious reliability problem and affects the normal operation of a satellite.In this paper,the different HPM response characteristics of two kinds of solar cells are comparatively researched by simulation.The results show that there are similarities and differences in hot spot distribution and damage mechanisms between both kinds of solar cell,which are related to the amplitude of HPM.In addition,the duty cycle of repetition frequency contributes more to the temperature accumulation of the solar cells than the carrier frequency.These results will help future research of damage assessment technology,reliability enhancement and the selection of materials for solar cells. 展开更多
关键词 solar cells SILICON GAAS HPM repetition frequency response characteristics
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The Seismic Response Characteristics of Polyhalite with Shaded Potash Mine in Central Sichuan
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作者 DING Feng ZHANG Yan +3 位作者 LI Meng LIU Wei PENG Da XU Xiang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期211-212,共2页
Potash deposition is the result of final phase of brine sedimentary evolution,it’s a limited distribution and easily soluble mineral,it is difficult to find the features on the ground,therefore the prospecting is ext... Potash deposition is the result of final phase of brine sedimentary evolution,it’s a limited distribution and easily soluble mineral,it is difficult to find the features on the ground,therefore the prospecting is extremely tough. 展开更多
关键词 POTASH exploration for oil and potash seismic exploration seismic response characteristics seismic attribute
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THE DYNAMIC PLASTIC RESPONSE CHARACTERISTICS OF CIRCULAR BEAM
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作者 王建军 刘晓坤 陈百屏 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1989年第7期599-609,共11页
In this paper the problem of a circular beam subjected to radial impact by a rigid mass at its lip in its own plane is investigaleil on the basis of rigid-perfectly plastic assumption. The analytical solution of the p... In this paper the problem of a circular beam subjected to radial impact by a rigid mass at its lip in its own plane is investigaleil on the basis of rigid-perfectly plastic assumption. The analytical solution of the particle velocities is obtained as the junction of travelling plastic hinge location. Ky analysing the solution, some special properties oj circular beam problem are found. 展开更多
关键词 THE DYNAMIC PLASTIC RESPONSE characteristicS OF CIRCULAR BEAM
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The Characteristic Analysis of the Electromagnetic Valve in Opening and Closing Process for the Gas Injection System
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作者 Linqian Yin Changshui Wu 《Journal of Electromagnetic Analysis and Applications》 2016年第8期152-159,共9页
In this paper, the mathematical model of solenoid valve in the fuel injection system of gas engine is built. Simulation software Matlab/Simulink are employed to analyze the impact which the voltage, number of the coil... In this paper, the mathematical model of solenoid valve in the fuel injection system of gas engine is built. Simulation software Matlab/Simulink are employed to analyze the impact which the voltage, number of the coil turns and air gap width may produce to the open and close characteristics of the solenoid valve. The ideal response characteristics are got through the calculation. An optimal scheme which satisfies the operation requirements is put forward. The driving voltage and maintaining voltage are set as 90 V and 21 V;number of the coil turns is 30 N;air gap is determined as 0.6 mm;the opening and closing time are respectively 0.98 ms and 0.8 ms. This paper can be used as a reference for the design of the solenoid valve. 展开更多
关键词 Solenoid Valve Response characteristics MATLAB/SIMULINK Fuel Injection System
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Quantitative estimation of bubble volume fraction of submarine seep plumes by modeling seismic oceanography data
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作者 Tonggang HAN Jiangxin CHEN +3 位作者 Leonardo AZEVEDO Bingshou HE Huaning XU Rui YANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第2期673-686,共14页
Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the l... Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the leaked gases frequently exhibit a flame-like structure.We numerically modelled the relationship between the seismic response characteristic and bubble volume fraction to establish the bubble volume fraction in the submarine seep plume.Results show that our models are able to invert and predict the bubble volume fraction from field seismic oceanography data,by which synthetic seismic sections in different dominant frequencies could be numerically simulated,seismic attribute sections(e.g.,instantaneous amplitude,instantaneous frequency,and instantaneous phase)extracted,and the correlation between the seismic attributes and bubble volume fraction be quantitatively determined with functional equations.The instantaneous amplitude is positively correlated with bubble volume fraction,while the instantaneous frequency and bubble volume fraction are negatively correlated.In addition,information entropy is introduced as a proxy to quantify the relationship between the instantaneous phase and bubble volume fraction.As the bubble volume fraction increases,the information entropy of the instantaneous phase increases rapidly at the beginning,followed by a slight upward trend,and finally stabilizes.Therefore,under optimal noise conditions,the bubble volume fraction of submarine seep plumes can be inverted and predicted based on seismic response characteristics in terms of seismic attributes. 展开更多
关键词 seismic oceanography submarine seep plumes bubble volume fraction seismic response characteristics seismic attribute analysis quantitative analysis
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Numerical Investigation on Dynamic Response Characteristics of Fluid-Structure Interaction of Gas-Liquid Two-Phase Flow in Horizontal Pipe
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作者 王志伟 何炎平 +4 位作者 李铭志 仇明 黄超 刘亚东 王梓 《Journal of Shanghai Jiaotong university(Science)》 EI 2024年第2期237-244,共8页
Fluid-structure interaction(FSI)of gas-liquid two-phase fow in the horizontal pipe is investigated numerically in the present study.The volume of fluid model and standard k-e turbulence model are integrated to simulat... Fluid-structure interaction(FSI)of gas-liquid two-phase fow in the horizontal pipe is investigated numerically in the present study.The volume of fluid model and standard k-e turbulence model are integrated to simulate the typical gas-liquid two-phase fow patterns.First,validation of the numerical model is conducted and the typical fow patterns are consistent with the Baker chart.Then,the FSI framework is established to investigate the dynamic responses of the interaction between the horizontal pipe and gas-liquid two-phase fow.The results show that the dynamic response under stratified fow condition is relatively flat and the maximum pipe deformation and equivalent stress are 1.8 mm and 7.5 MPa respectively.Meanwhile,the dynamic responses induced by slug fow,wave fow and annular fow show obvious periodic fuctuations.Furthermore,the dynamic response characteristics under slug flow condition are maximum;the maximum pipe deformation and equivalent stress can reach 4mm and 17.5 MPa,respectively.The principal direction of total deformation is different under various flow patterns.Therefore,the periodic equivalent stress will form the cyclic impact on the pipe wall and affect the fatigue life of the horizontal pipe.The present study may serve as a reference for FSI simulation under gas-liquid two-phase transport conditions. 展开更多
关键词 gas-liquid two-phase flow volume of fluid model fluid-structure interaction(FSI) dynamic response characteristics
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Temporal and spatial response of vegetation NDVI to temperature and precipitation in eastern China 被引量:36
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作者 CUI Linli SHI Jun 《Journal of Geographical Sciences》 SCIE CSCD 2010年第2期163-176,共14页
Temporal and spatial response characteristics of vegetation NDVI to the variation of temperature and precipitation in the whole year, spring, summer and autumn was analyzed from April 1998 to March 2008 based on the S... Temporal and spatial response characteristics of vegetation NDVI to the variation of temperature and precipitation in the whole year, spring, summer and autumn was analyzed from April 1998 to March 2008 based on the SPOT VGT-NDVI data and daily temperature and precipitation data from 205 meteorological stations in eastern China. The results indicate that as a whole, the response of vegetation NDVI to the variation of temperature is more pronounced than that of precipitation in eastern China. Vegetation NDVI maximally responds to the variation of temperature with a lag of about 10 days, and it maximally responds to the variation of precipitation with a lag of about 30 days. The response of vegetation NDVI to temperature and precipitation is most pronounced in autumn, and has the longest lag in summer. Spatially, the maximum response of vegetation NDVI to the variation of temperature is more pronounced in the northern and middle parts than in the southern part of eastern China. The maximum response of vegetation NDVI to the variation of precipitation is more pronounced in the northern part than in the middle and southern parts of eastern China. The response of vegetation NDVI to the variation of temperature has longer lag in the northern and southern parts than in the middle part of eastern China. The response of vegetation NDVl to the variation of precipitation has the longest lag in the southern part, and the shortest lag in the northern part of eastern China. The response of vegetation NDVI to the variation of temperature and precipitation in eastern China is mainly consistent with other results, but the lag time of vegetation NDVI to the variation of temperature and precipitation has some differences with those results of the monsoon region of eastern China. 展开更多
关键词 SPOT VGT-NDVI temperature PRECIPITATION response characteristics lag time eastern China
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Shaking table test for reinforcement of soil slope with multiple sliding surfaces by reinforced double-row anti-slide piles 被引量:6
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作者 WU Hong-gang PAI Li-fang 《Journal of Mountain Science》 SCIE CSCD 2022年第5期1419-1436,共18页
Despite the continuous advancements of engineering construction in high-intensity areas,many engineering landslides are still manufactured with huge thrust force,and double-row piles are effective to control such larg... Despite the continuous advancements of engineering construction in high-intensity areas,many engineering landslides are still manufactured with huge thrust force,and double-row piles are effective to control such large landslides.In this study,large shaking table test were performed to test and obtain multi-attribute seismic data such as feature image,acceleration,and dynamic soil pressure.Through the feature image processing analysis,the deformation characteristics for the slope reinforced by double-row piles were revealed.By analyzing the acceleration and the dynamic soil pressure time domain,the spatial dynamic response characteristics were revealed.Using Fast Fourier Transform and half-power bandwidth,the damping ratio of acceleration and dynamic soil pressure was obtained.Following that,the Seism Signal was used to calculate the spectral displacement of the accelerations to obtain the regional differences of spectral displacement.The results showed that the overall deformation mechanism of the slope originates from tension failure in the soil mass.The platform at the back of the slope was caused by seismic subsidence,and the peak acceleration ratio was positively correlated with the relative pile heights.The dynamic soil pressure of the front row piles showed an inverted"K"-shaped distribution,but that of the back row piles showed an"S"-shaped distribution.The predominant frequency of acceleration was 2.16 Hz,and the main frequency band was 0.7-6.87 Hz;for dynamic soil pressure,the two parameters became 1.15 Hz and 0.5-6.59 Hz,respectively.In conclusion,dynamic soil pressure was more sensitive to dampening effects than acceleration.Besides,compared to acceleration,dynamic soil pressure exhibited larger loss factors and lower resonance peaks.Finally,back row pile heads were highly sensitive to spectral displacement compared to front row pile heads.These findings may be of reference value for future seismic designs of double-row piles. 展开更多
关键词 Double row anti-slide piles multislide surface landslide Shaking table test ACCELERATION Dynamic soil pressure Dynamic response characteristic
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Fluid−Structure Interaction of Two-Phase Flow Passing Through 90° Pipe Bend Under Slug Pattern Conditions 被引量:2
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作者 WANG Zhi-wei HE Yan-ping +4 位作者 LI Ming-zhi QIU Ming HUANG Chao LIU Ya-dong WANG Zi 《China Ocean Engineering》 SCIE EI CSCD 2021年第6期914-923,共10页
Numerical simulations of evolution characteristics of slug flow across a 90°pipe bend have been carried out to study the fluid−structure interaction response induced by internal slug flow.The two-phase flow patte... Numerical simulations of evolution characteristics of slug flow across a 90°pipe bend have been carried out to study the fluid−structure interaction response induced by internal slug flow.The two-phase flow patterns and turbulence were modelled by using the volume of fluid(VOF)model and the Realizable k−εturbulence model respectively.Firstly,validation of the CFD model was carried out and the desirable results were obtained.The different flow patterns and the time-average mean void fraction was coincident with the reported experimental data.Simulations of different cases of slug flow have been carried out to show the effects of superficial gas and liquid velocity on the evolution characteristics of slug flow.Then,a one-way coupled fluid-structure interaction framework was established to investigate the slug flow interaction with a 90°pipe bend under various superficial liquid and gas velocities.It was found that the maximum total deformation and equivalent stress increased with the increasing superficial gas velocity,while decreased with the increasing superficial liquid velocity.In addition,the total deformation and equivalent stress has obvious periodic fluctuation.Furthermore,the distribution position of maximum deformation and stress was related to the evolution of slug flow.With the increasing superficial gas velocity,the maximum total deformation was mainly located at the 90°pipe bend.But as the superficial liquid velocity increases,the maximum total deformation was mainly located in the horizontal pipe section.Consequently,the slug flow with higher superficial gas velocity will induce more serious cyclical impact on the 90°pipe bend. 展开更多
关键词 two-phase flow 90°pipe bend slug flow fluid−structure interaction dynamic response characteristics
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Matrix test measurements of ground-borne vibration induced by the heavy-duty trains on embankment and cutting tracks in a loess area 被引量:2
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作者 Xie Qiang Wu Zhi-Hui +1 位作者 Dong Jie Zhong Shuai 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2021年第3期605-620,共16页
This paper presents a comparative analysis of ground vibration in three directions generated by a heavy-duty railway with various track sections.The vibration characteristics in the plane area were investigated by usi... This paper presents a comparative analysis of ground vibration in three directions generated by a heavy-duty railway with various track sections.The vibration characteristics in the plane area were investigated by using matrix test measurements.Acceleration peak attenuation was faster within 25 m from the embankment,and the high-frequency vibration attenuates faster with increased distance.For the cutting section with multi-stage soil slope,decay rate of acceleration was relatively larger.The acceleration level of the plane region ranged to 82.2-89.1 dB by the single C80 train.Yet the acceleration level caused by the C80 trains running parallel after meeting showed a distinct increment.The increment of the cutting section was much larger compared with the embankment section,with the increment ranging from 1.2-2.5 dB.In terms of the cutting section,Y direction acceleration was dominant closer to the track.Within 10-30 m of the track,the Y direction acceleration(perpendicular to the rail)decreased rapidly and became comparable to the X direction(parallel to the rail)and Z direction.Additionally,the cutting case generated a higher level of vibration in all three directions compared to the embankment,but as the distance from track increased,the deviation between acceleration gradually decreased. 展开更多
关键词 heavy-duty railway different track sections field measurement vibration response characteristics cutting slope
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Simple PID Parameter Tuning Method Based on Outputs of the Closed Loop System 被引量:12
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作者 HAN Jianda ZHU Zhiqiang +1 位作者 JIANG Ziya HE Yuqing 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第3期465-474,共10页
Most of the existing PID parameters tuning methods are only effective with pre-known accurate system models, which often require some strict identification experiments and thus infeasible for many complicated systems.... Most of the existing PID parameters tuning methods are only effective with pre-known accurate system models, which often require some strict identification experiments and thus infeasible for many complicated systems. Actually, in most practical engineering applications, it is desirable for the PID tuning scheme to be directly based on the input-output response of the closed-loop system. Thus, a new parameter tuning scheme for PID controllers without explicit mathematical model is developed in this paper. The paper begins with a new frequency domain properties analysis of the PID controller. After that, the definition of characteristic frequency for the PID controller is given in order to study the mathematical relationship between the PID parameters and the open-loop frequency properties of the controlled system. Then, the concepts of M-field and θ-field are introduced, which are then used to explain how the PID control parameters influence the closed-loop frequency-magnitude property and its time responses. Subsequently, the new PID parameter tuning scheme, i.e., a group of tuning rules, is proposed based on the preceding analysis. Finally, both simulations and experiments are conducted, and the results verify the feasibility and validity of the proposed methods. This research proposes a PID parameter tuning method based on outputs of the closed loop system. 展开更多
关键词 PID control characteristic frequency step response frequency property
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