A new method of detecting the vertical bearing capacity for single-pile with high strain is discussed in this paper. A heavy hammer or a small type of rocket is used to strike the pile top and the detectors are used ...A new method of detecting the vertical bearing capacity for single-pile with high strain is discussed in this paper. A heavy hammer or a small type of rocket is used to strike the pile top and the detectors are used to record vibra- tion graphs. An expression of higher degree of strain (deformation force) is introduced. It is testified theoretically that the displacement, velocity and acceleration cannot be obtained by simple integral acceleration and differential velocity when long displacement and high strain exist, namely when the pile phase generates a whole slip relative to the soil body. That is to say that there are non-linear relations between them. It is educed accordingly that the force P and displacement S are calculated from the amplitude of wave train and (dynamic) P-S curve is drew so as to determine the yield points. Further, a method of determining the vertical bearing capacity for single-pile is dis- cussed. A static load test is utilized to check the result of dynamic test and determine the correlative constants of dynamic-static P(Q)-S curve.展开更多
Several critical clinical applications of magnetocardiography(MCG)involve its T wave.The T wave’s accuracy directly affects the diagnostic accuracy of MCG for ischemic heart disease and arrhythmogenic.Tunnel magnetor...Several critical clinical applications of magnetocardiography(MCG)involve its T wave.The T wave’s accuracy directly affects the diagnostic accuracy of MCG for ischemic heart disease and arrhythmogenic.Tunnel magnetoresistance(TMR)attracts attention as a new MCG measurement technique.However,the T waves measured by TMR are often drowned in noise.The accuracy of T waves needs to be discussed to determine the clinical value of MCG measured by TMR.This study uses an improved empirical mode decomposition(EMD)algorithm and averaging to eliminate the noise in the MCG measured by TMR.The MCG signals measured by TMR are compared with MCG measured by the optically pumped magnetometer(OPM)to judge its accuracy.Using the MCG measured by OPM as a reference,the relative errors in time and amplitude of the T wave measured by TMR are 3.4%and 1.8%,respectively.This is the first demonstration that TMR can accurately measure the time and amplitude of MCG T waves.The ability to provide reliable T wave data illustrates the significant clinical application value of TMR in MCG measurement.展开更多
Petrophysical proprieties such as porosity, density, permeability and saturation have a marked impact on acoustic proprieties of rocks. Hence, there has been recently a strong incentive to use new geophysical techniqu...Petrophysical proprieties such as porosity, density, permeability and saturation have a marked impact on acoustic proprieties of rocks. Hence, there has been recently a strong incentive to use new geophysical techniques to invert such properties from seismic or sonic measurements for rocks characterization. The P-wave velocity, which is non-destructtive and easy method to apply in both field and laboratory conditions, has increasingly been conducted to determine the geotechnical properties of rock materials. The P-wave velocity of a rock is closely related to the intact rock properties, and been measuring the velocity in rock masses describes the rock structure and texture. The present work deals with the use of a simple and non-destructive technique, ultrasonic velocity, to predict the porosity and density of calcarenite rocks that are characteristic in historical monument. The ultrasonic test is based on measuring the propagation time of a P-wave in the longitudinal direction. Good correlations between P-wave velocity, porosity and density were found, which indicated them as an appropriate technique for estimating the porosity and density.展开更多
目的 观察原发性高血压患者室性心律失常易感性状况,并分析动态心电图P波离散度、T波峰-末(Tp-e)间期联合血压变异性对其预测效能。方法 纳入2020年6月至2022年6月医院126例原发性高血压患者为研究对象。入院时所有患者均接受动态心电...目的 观察原发性高血压患者室性心律失常易感性状况,并分析动态心电图P波离散度、T波峰-末(Tp-e)间期联合血压变异性对其预测效能。方法 纳入2020年6月至2022年6月医院126例原发性高血压患者为研究对象。入院时所有患者均接受动态心电图检查与血压变异性检查,记录P波离散度、Tp-e间期值,观察患者室性心律失常发生状况,并将其分为室性心律失常组与非室性心律失常组,分析动态心电图P波离散度、Tp-e间期联合血压变异性对原发性高血压患者室性心律失常易感性的预测效能。结果 126例原发性高血压患者中发生室性心律失常39例,占30.95%;室性心律失常组右心房横径(RAD)[(47.39±6.25)mm]长于非室性心律失常组[(40.37±6.74)mm],P波离散度[(42.82±8.14)ms]、Tp-e间期[(112.96±11.34)ms]、24 h舒张压标准差(24 h diastolic blood pressure standard deviation,24 h DPB-SD)[(13.79±5.22)mmHg]、24 h收缩压标准差(24 h systolic blood pressure standard deviation,24 h SBP-SD)值[(18.75±5.76)ms]高于非室性心律失常组[(36.16±7.28)ms、(99.23±12.61)ms、(9.78±4.36)mmHg、(14.03±5.17)mmHg](P<0.05);经点二列相关性分析显示,动态心电图P波离散度、Tp-e间期、血压变异性(24 h DPB-SD、24 h SBP-SD)值与原发性高血压患者发生室性心律失常呈正相关(r=0.276、0.463、0.207、0.293,P均<0.05);经logistic回归分析,结果显示,高P波离散度、高Tp-e间期、高24 h DPB-SD、高24 h SBP-SD是原发性高血压患者发生室性心律失常的危险因素(OR=1.112、1.095、1.199、1.177,P<0.05);ROC曲线结果显示,P波离散度、Tp-e间期、24 h DPB-SD、24 h SBP-SD预测原发性高血压患者发生室性心律失常的AUC分别为0.733(95%CI 0.635~0.830)、0.800(95%CI 0.723~0.877)、0.719(95%CI 0.621~0.817)、0.712(95%CI 0.614~0.810)、0.912(95%CI 0.863~0.961)。结论 动态心电图P波离散度、Tp-e间期联合血压变异性对原发性高血压患者室性心律失常易感性具有较高预测价值。展开更多
The April 25, 2015 Mw7.8 Nepal earthquake was successfully recorded by Crustal Movement Observation Network of China （CMONOC） and Nepal Geodetic Array （NGA）. We processed the high-rate GPS data （1 Hz and 5 Hz） b...The April 25, 2015 Mw7.8 Nepal earthquake was successfully recorded by Crustal Movement Observation Network of China （CMONOC） and Nepal Geodetic Array （NGA）. We processed the high-rate GPS data （1 Hz and 5 Hz） by using relative kinematic positioning and derived dynamic ground motions caused by this large earthquake. The dynamic displacements time series clearly indicated the displacement amplitude of each station was related to the rupture directivity. The stations which located in the di- rection of rupture propagation had larger displacement amplitudes than others. Also dynamic ground displacement exceeding 5 cm was detected by the GPS station that was 2000 km away from the epicenter. Permanent coseismic displacements were resolved from the near-field high-rate GPS stations with wavelet decomposition-reconstruction method and P-wave arrivals were also detected with S transform method. The results of this study can be used for earthquake rupture process and Earthquake Early Warning studies.展开更多
文摘A new method of detecting the vertical bearing capacity for single-pile with high strain is discussed in this paper. A heavy hammer or a small type of rocket is used to strike the pile top and the detectors are used to record vibra- tion graphs. An expression of higher degree of strain (deformation force) is introduced. It is testified theoretically that the displacement, velocity and acceleration cannot be obtained by simple integral acceleration and differential velocity when long displacement and high strain exist, namely when the pile phase generates a whole slip relative to the soil body. That is to say that there are non-linear relations between them. It is educed accordingly that the force P and displacement S are calculated from the amplitude of wave train and (dynamic) P-S curve is drew so as to determine the yield points. Further, a method of determining the vertical bearing capacity for single-pile is dis- cussed. A static load test is utilized to check the result of dynamic test and determine the correlative constants of dynamic-static P(Q)-S curve.
基金supported by the Suzhou Tsinghua innovation leading action project(Grant No.2016SZ0217)the National Key Research and Development Program of China(Grant No.2016YFB0500902)。
文摘Several critical clinical applications of magnetocardiography(MCG)involve its T wave.The T wave’s accuracy directly affects the diagnostic accuracy of MCG for ischemic heart disease and arrhythmogenic.Tunnel magnetoresistance(TMR)attracts attention as a new MCG measurement technique.However,the T waves measured by TMR are often drowned in noise.The accuracy of T waves needs to be discussed to determine the clinical value of MCG measured by TMR.This study uses an improved empirical mode decomposition(EMD)algorithm and averaging to eliminate the noise in the MCG measured by TMR.The MCG signals measured by TMR are compared with MCG measured by the optically pumped magnetometer(OPM)to judge its accuracy.Using the MCG measured by OPM as a reference,the relative errors in time and amplitude of the T wave measured by TMR are 3.4%and 1.8%,respectively.This is the first demonstration that TMR can accurately measure the time and amplitude of MCG T waves.The ability to provide reliable T wave data illustrates the significant clinical application value of TMR in MCG measurement.
文摘Petrophysical proprieties such as porosity, density, permeability and saturation have a marked impact on acoustic proprieties of rocks. Hence, there has been recently a strong incentive to use new geophysical techniques to invert such properties from seismic or sonic measurements for rocks characterization. The P-wave velocity, which is non-destructtive and easy method to apply in both field and laboratory conditions, has increasingly been conducted to determine the geotechnical properties of rock materials. The P-wave velocity of a rock is closely related to the intact rock properties, and been measuring the velocity in rock masses describes the rock structure and texture. The present work deals with the use of a simple and non-destructive technique, ultrasonic velocity, to predict the porosity and density of calcarenite rocks that are characteristic in historical monument. The ultrasonic test is based on measuring the propagation time of a P-wave in the longitudinal direction. Good correlations between P-wave velocity, porosity and density were found, which indicated them as an appropriate technique for estimating the porosity and density.
文摘目的 观察原发性高血压患者室性心律失常易感性状况,并分析动态心电图P波离散度、T波峰-末(Tp-e)间期联合血压变异性对其预测效能。方法 纳入2020年6月至2022年6月医院126例原发性高血压患者为研究对象。入院时所有患者均接受动态心电图检查与血压变异性检查,记录P波离散度、Tp-e间期值,观察患者室性心律失常发生状况,并将其分为室性心律失常组与非室性心律失常组,分析动态心电图P波离散度、Tp-e间期联合血压变异性对原发性高血压患者室性心律失常易感性的预测效能。结果 126例原发性高血压患者中发生室性心律失常39例,占30.95%;室性心律失常组右心房横径(RAD)[(47.39±6.25)mm]长于非室性心律失常组[(40.37±6.74)mm],P波离散度[(42.82±8.14)ms]、Tp-e间期[(112.96±11.34)ms]、24 h舒张压标准差(24 h diastolic blood pressure standard deviation,24 h DPB-SD)[(13.79±5.22)mmHg]、24 h收缩压标准差(24 h systolic blood pressure standard deviation,24 h SBP-SD)值[(18.75±5.76)ms]高于非室性心律失常组[(36.16±7.28)ms、(99.23±12.61)ms、(9.78±4.36)mmHg、(14.03±5.17)mmHg](P<0.05);经点二列相关性分析显示,动态心电图P波离散度、Tp-e间期、血压变异性(24 h DPB-SD、24 h SBP-SD)值与原发性高血压患者发生室性心律失常呈正相关(r=0.276、0.463、0.207、0.293,P均<0.05);经logistic回归分析,结果显示,高P波离散度、高Tp-e间期、高24 h DPB-SD、高24 h SBP-SD是原发性高血压患者发生室性心律失常的危险因素(OR=1.112、1.095、1.199、1.177,P<0.05);ROC曲线结果显示,P波离散度、Tp-e间期、24 h DPB-SD、24 h SBP-SD预测原发性高血压患者发生室性心律失常的AUC分别为0.733(95%CI 0.635~0.830)、0.800(95%CI 0.723~0.877)、0.719(95%CI 0.621~0.817)、0.712(95%CI 0.614~0.810)、0.912(95%CI 0.863~0.961)。结论 动态心电图P波离散度、Tp-e间期联合血压变异性对原发性高血压患者室性心律失常易感性具有较高预测价值。
基金supported by Director Foundation of Institute of Seismology,China Earthquake Administration(IS201426142)National Natural Science Foundation of China(41541029,41574017, 41274027)+1 种基金Natural Science Foundation of HuBei Province (2015CFB642)provided by Crustal Movement Observation Network of China(CMONOC) and UNAVCO
文摘The April 25, 2015 Mw7.8 Nepal earthquake was successfully recorded by Crustal Movement Observation Network of China （CMONOC） and Nepal Geodetic Array （NGA）. We processed the high-rate GPS data （1 Hz and 5 Hz） by using relative kinematic positioning and derived dynamic ground motions caused by this large earthquake. The dynamic displacements time series clearly indicated the displacement amplitude of each station was related to the rupture directivity. The stations which located in the di- rection of rupture propagation had larger displacement amplitudes than others. Also dynamic ground displacement exceeding 5 cm was detected by the GPS station that was 2000 km away from the epicenter. Permanent coseismic displacements were resolved from the near-field high-rate GPS stations with wavelet decomposition-reconstruction method and P-wave arrivals were also detected with S transform method. The results of this study can be used for earthquake rupture process and Earthquake Early Warning studies.
