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Estimation of the unfrozen water content of saturated sandstones by ultrasonic velocity 被引量:2
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作者 Shibing Huang Fei Liu +1 位作者 Gang Liu Shilin Yu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第6期733-746,共14页
The unfrozen water content(UWC)of rocks at low temperature is an important index for evaluating the stability of the rock engineering in cold regions and artificial freezing engineering.This study addresses a new meth... The unfrozen water content(UWC)of rocks at low temperature is an important index for evaluating the stability of the rock engineering in cold regions and artificial freezing engineering.This study addresses a new method to estimate the UWC of saturated sandstones at low temperature by using the ultrasonic velocity.Ultrasonic velocity variations can be divided into the normal temperature stage(20 to 0℃),quick phase transition stage(0 to-5℃)and slow phase transition stage(-5 to-25℃).Most increment of ultrasonic velocity is completed in the quick phase transition stage and then turns to be almost a constant in the slow phase transition stage.In addition,the UWC is also measured by using nuclear magnetic resonance(NMR)technology.It is validated that the ultrasonic velocity and UWC have a similar change law against freezing and thawing temperatures.The WE(weighted equation)model is appropriate to estimate the UWC of saturated sandstones,in which the parameters have been accurately determined rather than by data fitting.In addition,a linear relationship between UWC and ultrasonic velocity is built based on pore ice crystallization theory.It is evidenced that this linear function can be adopted to estimate the UWC at any freezing temperature by using P-wave velocity,which is simple,practical,and accurate enough compared with the WE model. 展开更多
关键词 ultrasonic velocity Freeze-thaw cycles Unfrozen water content Prediction function Hysteresis effect
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Visualisation of air–water bubbly column flow using array Ultrasonic Velocity Profiler 被引量:2
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作者 Munkhbat Batsaikhan Ari Hamdani Hiroshige Kikura 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2017年第6期379-385,共7页
In the present work, an experimental study of bubbly two-phase flow in a rectangular bubble column was performed using two ultrasonic array sensors, which can measure the instantaneous velocity of gas bubbles on multi... In the present work, an experimental study of bubbly two-phase flow in a rectangular bubble column was performed using two ultrasonic array sensors, which can measure the instantaneous velocity of gas bubbles on multiple measurement lines. After the sound pressure distribution of sensors had been evaluated with a needle hydrophone technique, the array sensors were applied to two-phase bubble col- umn, To assess the accuracy of the measurement system with array sensors for one and two-dimensional velocity, a simultaneous measurement was performed with an optical measurement technique called particle image velocimetry (PIV). Experimental results showed that accuracy of the measurement system with array sensors is under 10% for one-dimensional velocity profile measurement compared with PIV technique. The accuracy of the system was estimated to be under 20% along the mean flow direction in the case of two-dimensional vector mapping. 展开更多
关键词 Two-phase bubbly flow Bubble column ultrasonic velocity Profiler (UVP) Sectorial array sensor
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Early Age Hydration of Cement Paste Monitored with Ultrasonic Velocity and Numerical Simulation 被引量:1
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作者 陈伟 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第4期704-707,共4页
Early age hydration of cement paste was investigated by monitoring the ultrasonic propagation velocity and simulated with the numerical model CEMHYD3D. The ultrasonic velocity of the P-wave was recorded during the fir... Early age hydration of cement paste was investigated by monitoring the ultrasonic propagation velocity and simulated with the numerical model CEMHYD3D. The ultrasonic velocity of the P-wave was recorded during the first 24 hours of the hydration process and its evolution was analyzed. It is shown that the UPV method is an effective, accurate and non-destructive method for monitoring the early age hydration process of cement paste. The early age hydration process can be classified as four periods, which are the dormant period, acceleration period, deceleration period and stabilization period. Higher w/c ratios result in lower UPV, and delay initial setting time due to the decreased solid volume. The change of UPV is clearly related to the hydration degree of cement particles. 展开更多
关键词 early age hydration ultrasonic velocity hydration degree CEMHYD3D
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Damage Evolution of Ballastless Track Concrete Exposed to Flexural Fatigue Loads:The Application of Ultrasonic Pulse Velocity,Impact-echo and Surface Electrical Resistance Method
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作者 杨志强 李化建 +4 位作者 WEN Jiaxing DONG Haoliang HUANG Fali WANG Zhen YI Zhonglai 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期353-363,共11页
In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were used.Damage variab... In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were used.Damage variable based on the change of velocity of ultrasonic pulse(Du) and impact elastic wave(Di)were defined according to the classical damage theory.The influences of stress level,loading frequency and concrete strength on damage variable were measured.The experimental results show that Du and Di both present a three-stages trend for concrete exposed to fatigue loads.Since impact elastic wave is more sensitive to the microstructure damage in stage Ⅲ,the critical damage variable,i e,the damage variable before the final fracture of concrete of Di is slightly higher than that of Du.Meanwhile,the evolution of SR of concrete exposed to fatigue loads were analyzed and the relationship between SR and Du,SR and Di of concrete exposed to fatigue loads were established.It is found that the SR of concrete was decreased with the increasing fatigue cycles,indicating that surface electrical resistance method can also be applied to describe the damage of ballastless track concrete exposed to fatigue loads. 展开更多
关键词 ballastless track fatigue damage ultrasonic pulse velocity IMPACT-ECHO surface electrical resistance
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Micro-destructive assessment of subgrade compaction quality using ultrasonic pulse velocity
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作者 Xuefei Wang Xuping Dong +3 位作者 Xiangdong Li Jianmin Zhang Guowei Ma Jiale Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4782-4797,共16页
The ultrasonic pulse velocity(UPV)correlates significantly with the density and pore size of subgrade filling materials.This research conducts numerous Proctor and UPV tests to examine how moisture and rock content af... The ultrasonic pulse velocity(UPV)correlates significantly with the density and pore size of subgrade filling materials.This research conducts numerous Proctor and UPV tests to examine how moisture and rock content affect compaction quality.The study measures the changes in UPV across dry density and compaction characteristics.The compacted specimens exhibit distinct microstructures and mechanical properties along the dry and wet sides of the compaction curve,primarily influenced by internal water molecules.The maximum dry density exhibits a positive correlation with the rock content,while the optimal moisture content demonstrates an inverse relationship.As the rock content increases,the relative error of UPV measurement rises.The UPV follows a hump-shaped pattern with the initial moisture content.Three intelligent models are established to forecast dry density.The measure of UPV and PSO-BP-NN model quickly assesses compaction quality. 展开更多
关键词 SUBGRADE Compaction quality ultrasonic pulse velocity(UPV) Intelligent model Proctor test Micro-destructive evaluation
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Effect of Curing Age on Tensile Properties of Fly Ash Based Engineered Geopolymer Composites(FA-EGC)by Uniaxial Tensile Test and Ultrasonic Pulse Velocity Method
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作者 GUO Xiaolu LI Shuyue 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第6期1319-1325,共7页
Tensile properties of fly ash based engineered geopolymer composites(FA-EGC)at different curing ages were studied by uniaxial tensile test and ultrasonic pulse velocity(UPV)methods,which included uniaxial tensile prop... Tensile properties of fly ash based engineered geopolymer composites(FA-EGC)at different curing ages were studied by uniaxial tensile test and ultrasonic pulse velocity(UPV)methods,which included uniaxial tensile properties,the correlation between ultrasonic pulse velocity and tensile properties,and characteristic parameters of microcracks.The experimental results show that obvious strain hardening behavior can be found in FA-EGC at different curing ages.With the increase of curing age,the tensile strength increases,the tensile strain decreases and the toughness becomes worse.The UPV of FA-EGC increases with curing age,and a strong correlation can be found between tensile strength and UPV.With the increase of curing age,the average crack width of FA-EGC decreases and the total number of cracks increases.This is because the strength of geopolymer increases fast at early age,thus the later strength development of FA-EGC tend to be stable.At the same time,the bond strength between fiber and matrix,and the friction of fiber/matrix interface continue to increase with curing age,thus the bridging effect of fiber is gradually strengthened.In conclusion,the increase of curing age is beneficial to the development of tensile properties of FA-EGC. 展开更多
关键词 engineered geopolymer composites(EGC) tensile properties ultrasonic pulse velocity(UPV) characteristic parameters of microcracks
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Effect of diffraction on the ultrasonic velocity measuredby the pulse interference method in VHF range 被引量:1
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作者 WEI Tingcun(Department of Electrical Engineering, Tohoku University Japan) 《Chinese Journal of Acoustics》 2002年第1期30-35,共6页
The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, thei... The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, their frequency dependences of longitudinal velocities are measured in the frequency range of 50-350 MHz, and the phase advances of ultrasonic signals caused by diffraction effect are calculated using A. O. Williams' theoretical expression. For the velocity error due to diffraction effect, the experimental results are in good agreement with the theoretical prediction. It has been shown that the velocity error due to diffraction effect is directly proportional to dθ21 (f)/df, whereθ21 (f) is the phase advances difference between the two partial reflection signals used in velocity measurement and f is the ultrasonic frequency. 展开更多
关键词 Effect of diffraction on the ultrasonic velocity measuredby the pulse interference method in VHF range VHF
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Accurate measurement of ultrasonic velocity by eliminating the diffraction effect
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作者 WEI Tingcun(Department of Electrical Engineering, Tohoku University Japan) 《Chinese Journal of Acoustics》 2003年第3期217-221,共5页
The accurate measurement method of ultrasonic velocity by the pulse interference method with eliminating the diffraction effect has been investigated in VHF range experimentally. Two silicate glasses were taken as the... The accurate measurement method of ultrasonic velocity by the pulse interference method with eliminating the diffraction effect has been investigated in VHF range experimentally. Two silicate glasses were taken as the specimens, their frequency dependences of longitudinal velocities were measured in the frequency range 50-350 MHz, and the phase advances of ultrasonic signals caused by diffraction effect were calculated using A. O. Williams' theoretical expression. For the frequency dependences of longitudinal velocities, the measurement results were in good agreement with the simulation ones in which the phase advances were included. It has been shown that the velocity error due to diffraction effect can be corrected very well by this method. 展开更多
关键词 of AS on IT by Accurate measurement of ultrasonic velocity by eliminating the diffraction effect into IS that been
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Measurement errors of ultrasonic velocity and attenuation due to nonparallelness of specimen faces
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作者 WEI Tingcun(Department of Electrical Engineering, Tohoku University Japan) 《Chinese Journal of Acoustics》 2003年第2期113-120,共8页
The measurement errors due to nonparallelness of specimen faces in the ultrasonic velocity and attenuation coefficient measured by the pulse reflection method in VHF range have been investigated theoretically, and the... The measurement errors due to nonparallelness of specimen faces in the ultrasonic velocity and attenuation coefficient measured by the pulse reflection method in VHF range have been investigated theoretically, and the theoretical expressions for estimating these measurement errors are given. It has also been shown that, the attenuation coefficient error is depending on both the nonparallelness angle of specimen faces and the ultrasonic frequency, but the velocity error is only depending on the former. Furthermore, for pure silica glass specimen it is estimated that, in VHF range in order to insure that the attenuation coefficient and velocity errors due to nonparallelness of specimen faces are less than 10% and 0.01%, respectively, the nonparallelness angle of specimen faces must be less than 10 s and 40 s correspondingly. 展开更多
关键词 of on IT AS Measurement errors of ultrasonic velocity and attenuation due to nonparallelness of specimen faces that IS
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Dependence of the coefficient of ultrasonic velocity on the coefficient of free length in organic liquids
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作者 LU Yigang PENG Jianxin (Department of Applied Physics, South China University of Technology Guangzhou 510641) TONG Jie DONG Yanwu (Applied Acoustics institute, Shaanxi Normal University Xi’an 710062) 《Chinese Journal of Acoustics》 2000年第1期79-82,共4页
On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity... On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity and the pressure coefficient of free length, and the relationship between the temperature coefficient of ultrasonic velocity and the temperature coefficient of free length were studied. Relevant equations were given, and the pressure coefficient and temperature coefficient of ultrasonic velocity were calculated, which are in agreement with the measured values. 展开更多
关键词 LENGTH Dependence of the coefficient of ultrasonic velocity on the coefficient of free length in organic liquids free
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Effects of Transverse Temperature Gradient on the Rotor Velocity in an Ultrasonic Motor
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作者 程利平 张淑仪 徐晓东 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第1期72-74,共3页
As a result of the nonlinear effect, acoustic streaming has been widely used for increasing the transport coefficient or driving a rotor, for example, in resonant cavities and non-contact ultrasonic motors. It has bee... As a result of the nonlinear effect, acoustic streaming has been widely used for increasing the transport coefficient or driving a rotor, for example, in resonant cavities and non-contact ultrasonic motors. It has been demonstrated by experiments that a temperature gradient transverse to the wave propagating direction can significantly increase the velocity of the streaming flows in resonant cavities. To check whether the transverse temperature gradient can also increase the working velocity of acoustic streaming-driven motors, we investigate this issue by numerically solving the hydrodynamic equations. It is found that the velocity of the rotor only weakly depends on the transverse temperature gradient, e.g., even with a temperature difference of 40℃ between the rotor and the stator, the velocity increases only -8.8%. 展开更多
关键词 of it Effects of Transverse Temperature Gradient on the Rotor velocity in an ultrasonic Motor in for IS on
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Prediction of Compressive Strength Using Ultrasonic Pulse Velocity for CLSM with Waste LCD Glass Concrete
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作者 Chien-Chih Wang Her-Yung Wang +1 位作者 Chih-Hsien Chen Chi Huang 《Journal of Civil Engineering and Architecture》 2015年第6期691-700,共10页
The purpose of this paper is to develop a prediction model of WGCLSM (waste LCD (liquid crystal display) glass controlled low strength materials) concrete, the relationship between UPV (ultrasonic pulse velocity... The purpose of this paper is to develop a prediction model of WGCLSM (waste LCD (liquid crystal display) glass controlled low strength materials) concrete, the relationship between UPV (ultrasonic pulse velocity) and compressive strength, UPV-strength model. The power function was used to perform the nonlinear-multivariate regression analysis of UPV with water-binder ratio (w/b), curing age (t) and waste glass content (G) in our previous study. Test results show that the compressive strength increases with UPV and approach to a linear relationship. Thus, the UPV-strength model was established by linear-multivariate regression analysis and the compressive strength evaluated by ultrasonic pulse velocity. The calculated results are in accordance with the laboratory measured data ultrasonic pulse velocity and compressive strength. In addition, the statistical analysis shows that the coefficient of determination R2 and the MAPE (mean absolute percentage error) were from 0.916 to 0.951 and 12.6% to 15.1% for the compressive strength, respectively. The proposed models are highly accurate in predicting the compressive and ultrasonic pulse velocity of WGCLSM concrete. However, with other ranges of mixture parameters, the predicted models must be further studied. 展开更多
关键词 Glass concrete CLSM ultrasonic pulse velocity compressive strength.
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Statistical Modelling of Ultrasonic Pulse Velocity of Fly Ash Based Geopolymer Mortar using Response Surface Methodology
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作者 Muhammad Zahid Nasir Shafiq Muhammad Ali 《Journal of Architectural Environment & Structural Engineering Research》 2019年第4期11-17,共7页
The fly ash based geopolymer has emerged as a capable and sustainable binder material in construction industry.Ultrasonic pulse velocity(UPV)method is a non-destructive technique for investigating the mechanical perfo... The fly ash based geopolymer has emerged as a capable and sustainable binder material in construction industry.Ultrasonic pulse velocity(UPV)method is a non-destructive technique for investigating the mechanical performance of concrete.Experimental investigation was performed for studying the effect of NaOH Molarity,Na2SiO3/NaOH and curing temperature on the ultrasonic pulse velocity of geopolymer mortar.Experiments were designed based on central composite design(CCD)technique of response surface methodology(RSM).Statistical model was developed and statistically validated and found significant as the difference between adjustable R-squared and predicted R-squared less than 0.2.Finally,the optimized mix proportion was assessed for maximized value of UPV.Experimental validation on the optimized mix reveals the close agreement between experimental and predicted values of UPV with significance level of more than 95%.The proposed technique improves the yield,the reliability of the product and the processes. 展开更多
关键词 GEOPOLYMER Fly ash NaOH molarity Na2SiO3/NaOH Curing temperature ultrasonic pulse velocity Response surface methodology OPTIMIZATION
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Ultrasonic Study on Charge Ordering in Nd0.5Ca0.5Mn1-xAlxO3(x=0,0.03)
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作者 刘毅 孔辉 +1 位作者 苏金瑞 朱长飞 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第6期535-538,共4页
The ultrasonic, magnetic and transport properties of Nd0.5Ca0.5Mn1-xAlxO3 (x=0, 0.03) were studied from 15 to 300 K. The temperature dependencies of resistivity and magnetization show that Nd0.5Ca0.5MnO3 undergoes a... The ultrasonic, magnetic and transport properties of Nd0.5Ca0.5Mn1-xAlxO3 (x=0, 0.03) were studied from 15 to 300 K. The temperature dependencies of resistivity and magnetization show that Nd0.5Ca0.5MnO3 undergoes a charge ordering transition at TCO-257 K. An obvious softening of the longitudinal sound velocity above TCO and a dramatic stiffening below Too accompanied by an attenuation peak were observed. These features imply a strong electron phonom interaction via the Jahn-Teller effect iu the sample, Another broad attenuation peak was observed at around Tp-80 K. This anomaly is attributed to the phase separtion between the antiferromagnetic (AFM) and paramagnetic (PM) phases and gives a direct evidence for spin-phonon coupling in the compound. For the x=0.03 sample, both the minimum of sound velocity and attenuation peaks shift to a lower temperature. The results indicate that the charge ordering and CE-type AFM state in Nd0.5Ca0.5MnO3 are both partially suppressed by replacing Mn with A1. 展开更多
关键词 MANGANITE Charge ordering Phase separation ultrasonic velocity and attenuation
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Ultrasonic study on organic liquid and binary organic liquid mixtures by using Schaaffs' collision factor theory 被引量:1
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作者 卢义刚 董彦武 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第9期2030-2035,共6页
Based on Schaaff's collision factor theory (CFT) in liquids, the equations for nonlinear ultrasonic parameters in both organic liquid and binary organic liquid mixtures are deduced. The nonlinear ultrasonic paramet... Based on Schaaff's collision factor theory (CFT) in liquids, the equations for nonlinear ultrasonic parameters in both organic liquid and binary organic liquid mixtures are deduced. The nonlinear ultrasonic parameters, including pressure coefficient, temperature coefficients of ultrasonic velocity, and nonlinear acoustic parameter B/A in both organic liquid and binary organic liquid mixtures, are evaluated for comparison with the measured results and data from other sources. The equations show that the coefficient of ultrasonic velocity and nonlinear acoustic parameter B/A are closely related to molecular interactions. These nonlinear ultrasonic parameters reflect some information of internal structure and outside status of the medium or mixtures. From the exponent of repulsive forces of the molecules, several thermodynamic parameters, pressure and temperature of the medium, the nonlinear ultrasonic parameters and ultrasonic nature of the medium can be evaluated. When evaluating and studying nonlinear acoustic parameter B/A of binary organic liquid mixtures, there is no need to know the nonlinear acoustic parameter B/A of the components. Obviously, the equation reveals the connection between the nonlinear ultrasonic nature and internal structure and outside status of the mixtures more directly and distinctly than traditional mixture law for B/A, e.g. Apfel's and Sehgal's laws for liquid binary mixtures. 展开更多
关键词 nonlinear acoustic parameter B/A coefficient of ultrasonic velocity organic liquid binary organic liquid mixtures
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Development of Measurement System for Flow and Shape Using Array Ultrasonic Sensors 被引量:2
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作者 Munkhbat Batsaikhan Zeliang Zhang +1 位作者 Hideharu Takahashi Hiroshige Kikura 《Journal of Flow Control, Measurement & Visualization》 2021年第3期45-72,共28页
In Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the fuel debris formed in the Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) at Unit 1</span><span style="font-family:Verdan... In Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the fuel debris formed in the Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) at Unit 1</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">3. To accelerate and decide further decommissioning steps of the FDNPP, it is crucial to obtain realistic information of the debris and localize contaminated water leakage from PCV. Due to high radiation and dark environment inside the PCV, investigating instruments and techniques should necessarily to meet specification of radiation resistance, waterproofness, dust resistance and so on. This study focuses on development of ultrasonic measurement system using a couple of sectorial array sensors to localize contaminated water leakage and visualize shape of object that repre</span><span style="font-family:Verdana;">- </span><span style="font-family:Verdana;">senting fuel debris, simultaneously. In this study, Total Focusing Method</span><span style="font-family:Verdana;"> (TFM) and Ultrasonic Velocity Profiler (UVP) methods are considered to visualize object shape and flow pattern around it, respectively. To demonstrate applicability and reliability of developed measurement system with sectorial array sensors, a mock-up experiment result</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">of simulated water leakage and fuel debris shape were discussed in this paper. 展开更多
关键词 Reactor Decommissioning Sectorial Array Sensors Total Focusing Method (TFM) ULTRASOUND ultrasonic velocity Profiler (UVP) Vector Flow Mapping
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ULTRASONIC BEHAVIOR OF EPOXY RESINS/POLY (ETHYLENE OXIDE) BLENDS CURED WITH PHTHALIC ANHYDRIDE
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作者 郑思珣 王海千 +4 位作者 罗筱烈 张乃斌 马德柱 朱长飞 胡建恺 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第1期20-27,共8页
By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found... By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased. 展开更多
关键词 Pulse-echo method ultrasonic velocity Attenuation coefficient (α) Epoxy resins /poly (ethylene oxide)blends Crosslinking network
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Ultrasonic Study on Jahn-Teller Distortions in La1/3Sr2/3CoO3
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作者 Jian-xing Yi Hui Kong Chang-fei Zhu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2008年第2期136-140,共5页
The longitudinal ultrasonic velocity (V1), attenuation (α1), magnetization and resistivity of single phase polycrystalline La1/3Sr2/3CoO3 were measured as a function of temperature from 20 K to 300 K. The resisti... The longitudinal ultrasonic velocity (V1), attenuation (α1), magnetization and resistivity of single phase polycrystalline La1/3Sr2/3CoO3 were measured as a function of temperature from 20 K to 300 K. The resistivity shows metallic behavior in the whole temperature range and a kink at 235 K was observed, which coincides with the ferromagnetic transition temperature (Tc). As the temperature cools down from Tc, the V1 softens conspicuously at beginning and reaches a minimum at 120 K. After that the V1 dramatically stiffens below 120 K accompanied by a wide attenuation peak. The analysis of the results suggests that these ultrasonic anomalies ;nay correspond to local lattice distortions via the Jahn-Teller effect of intermediate spin Co^3+. 展开更多
关键词 La1/3Sr2/3CoO3 ultrasonic velocity and attenuation Jahn-Teller effect
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Creep properties and resistivity-ultrasonic-AE responses of cemented gangue backfill column under high-stress area 被引量:11
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作者 Hongyu Ran Yuxia Guo +2 位作者 Guorui Feng Tingye Qi Xianjie Du 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2021年第3期401-412,共12页
To investigate the creep and instability properties of a cemented gangue backfill column under a highstress area,the uniaxial compression creep tests were conducted by single-step and multi-step loading of prismatic s... To investigate the creep and instability properties of a cemented gangue backfill column under a highstress area,the uniaxial compression creep tests were conducted by single-step and multi-step loading of prismatic samples made of cemented gangue backfill material(CGBM)under the high stressstrength ratio.The creep damage was monitored using an electrical resistivity device,ultrasonic testing device,and acoustic emission(AE)instrument.The results showed that the CGBM sample has a creep hardening property.The creep failure strength(CFS)is slightly larger than the uniaxial compressive strength(UCS),ranging in ratio from 108.9%to 116.5%.The instantaneous strain,creep strain,and creep rate increase with increasing stress-strength ratio in the single-step loading creep tests.The instantaneous strain and creep strain decrease first and then increase during the multi-step loading creep process.The axial creep strain of the CGBM column can be expressed by the viscoelastic-plastic creep model.Creep instability is caused by the accumulation of strain energy under multi-step loading and the continuous lateral expansion at the unconstrained middle position during the creep process.The creep stability of a CGBM column in a high-stress area can be monitored based on the variation of electrical resistivity,ultrasonic pulse velocity(UPV),and AE signals. 展开更多
关键词 Cemented gangue backfill column Creep and instability properties High-stress area Electrical resistivity ultrasonic pulse velocity Acoustic emission
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Review on second-harmonic generation of ultrasonic guided waves in solid media(Ⅰ): Theoretical analyses 被引量:1
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作者 李卫彬 邓明晰 项延训 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期51-65,共15页
Considering the high sensitivity of the nonlinear ultrasonic measurement technique and great advantages of the guided wave testing method, the use of nonlinear ultrasonic guided waves provides a promising means for ev... Considering the high sensitivity of the nonlinear ultrasonic measurement technique and great advantages of the guided wave testing method, the use of nonlinear ultrasonic guided waves provides a promising means for evaluating and characterizing the hidden and/or inaccessible damage/degradation in solid media. Increasing attention on the development of the testing method based on nonlinear ultrasonic guided waves is largely attributed to the theoretical advances of nonlinear guided waves propagation in solid media. One of the typical acoustic nonlinear responses is the generation of second harmonics that can be used to effectively evaluate damage/degradation in materials/structures. In this paper, the theoretical progress of second-harmonic generation(SHG) of ultrasonic guided wave propagation in solid media is reviewed. The advances and developments of theoretical investigations on the effect of SHG of ultrasonic guided wave propagation in different structures are addressed. Some obscure understandings and the ideas in dispute are also discussed. 展开更多
关键词 second-harmonic generation(SHG) ultrasonic guided waves cumulative growth effect phase and group velocity matching
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