Based on the measurement of the arrival time of maxima magnitude from band-pass filtering signals which were determined using a new Morlet wavelet multiple-filter method, we develop a method for measuring intrinsic an...Based on the measurement of the arrival time of maxima magnitude from band-pass filtering signals which were determined using a new Morlet wavelet multiple-filter method, we develop a method for measuring intrinsic and attenuative dispersion of the first cycle direct P-wave. We determine relative group delays of spectral components of direct P-waves for 984 ray paths from SML and ALS stations of the Taiwan Central Weather Bureau Seismic Network （CWBSN）. Using continuous relaxation model, we deduce a new transfer function that relates intrinsic dispersion to attenuation. Based on the genetic algorithm （GA）, we put forward a new inversion procedure for determining which is defined the flat part of quality factor Q（ω） spectrum, τ1 and τ2 parameters. The results indicate that ① The distribution of Om values versus epicentral distance and depth show that Qm values linearly increase with increasing of epicentral distance and depth, and Qm values is clearly independent of earthquakes magnitude; ② In the different depth ranges, Qm residual show no correlation with variations in epicentral distance. Some significant changes of Qm residual with time is likely caused by pre-seismic stress accumulation, and associated with fluid-filled higher density fractures rock volume in the source area of 1999 Chi-Chi Taiwan earthquake. We confirm that Qm residual with time anomaly appears about 2.5 years before the Chi-Chi earthquake; ③ A comparison of Qm residual for different depth range between SML and ALS stations show that the level of stress has vertical and lateral difference; ④ The area near observation station with both anomalously increasing and decreasing averaged Qm residual is likely an unstable environment for future strong earthquake occurrence. This study demonstrates the capability of direct P-waves dispersion for monitoring attenuation characteristics and its state changes of anelastic medium of the Earth at short propagation distance using seismograms recorded from very small events.展开更多
AIM:To investigate the P wave dispersion as a non-invasive marker of intra-atrial conduction disturbances in patients with Wilson's disease. METHODS:We compared Wilson's disease patients (n = 18) with age matc...AIM:To investigate the P wave dispersion as a non-invasive marker of intra-atrial conduction disturbances in patients with Wilson's disease. METHODS:We compared Wilson's disease patients (n = 18) with age matched healthy subjects (n = 15) as controls. The diagnosis was based on clinical symptoms, laboratory tests (ceruloplasmin, urinary and hepatic copper concentrations). P wave dispersion, a measurement of the heterogeneity of atrial depolarization, was measured as the difference between the duration of the longest and the shortest P-waves in 12 lead electrocardiography. RESULTS:All the patients were asymptomatic on cardiological examination and have sinusal rhythm in electrocardiography. Left ventricular and left atrial diameters, left ventricular ejection fraction and left ventricular mass index were similar in both groups. The Wilson's disease patients had a significantly higher P wave dispersion compared with the controls (44.7 ± 5.8 vs 25.7 ± 2.5, P < 0.01). CONCLUSION:There was an increase in P wave dispersion in cardiologically asymptomatic Wilson's disease patients which probably represents an early stage of cardiac involvement.展开更多
Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions...Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions has been determined. The results show that the pattern of velocity anomalies in the shallower upper crust is somewhat associated with the surface geological tectonics in the region. A relative low-velocity anomaly appears north of the Wangwu-Wenjiao fault zone and a relative high-velocity anomaly appears south of the Wangwu-Wenjiao fault zone,corresponding to the depressed areas in north Hainan Island,where many volcanoes are frequently active and geothermal values are relatively higher,and the uplifted and stable regions in central and south of the Hainan Is-land. In the middle and lower crust velocities are relatively lower in east Hainan than those in west Hainan,possi-bly suggesting the existence of the upwelling of hot materials from the mantle in east Hainan. The pattern of veloc-ity anomalies also indicates that NW faults,i.e.,the Puqian-Qinglan fault,may be shallower,while the E-W Wangwu-Wenjiao fault may be deeper,which perhaps extends down to Moho depth or deeper.展开更多
Objective: The aim of the study was to investigate the impact of P-maximum and P-wave dispersion on the long term clinical outcome after successful percutaneous balloon mitral valvuloplasty (PBMV) in patients with mit...Objective: The aim of the study was to investigate the impact of P-maximum and P-wave dispersion on the long term clinical outcome after successful percutaneous balloon mitral valvuloplasty (PBMV) in patients with mitral stenosis (MS) and sinus rhythm. Also to test the correlation between P-variables and right ventricular function and pulmonary artery pressure before and after PMBV. Methods: Eighty-five patients undergoing PMBV were enrolled in this study. We evaluated P-maximum, P-minimum and P-wave dispersion before and one month after PBMV. We studied the changes in pulmonary arterial pressure (PAP), left atrial (LA) dimension, mitral diastolic gradient, and mitral valve area, in addition to the changes in right ventricular function utilizing tissue Doppler assessment both before and after PMBV, in addition the role of the P-wave dispersion in predicttion of late cardiac events. Results: There were significant decreases in mean diastolic gradient, PAP, and LA size and significant improvement in right ventricular tissue Doppler indices after PMBV. Ac- company these hemodynamic changes after PMBV. P-maximum and P-wave dispersion were found to be decreased (P < 0.001). Patients developed cardiac events during follow-up had a higher P-maximum and P-dispersion than those without late cardiac events (P < 0.001). Moreover the changes in P-maxi- mum and P-dispersion before and after PMBV in patients with cardiac events were not significant, while P-maximum and P-dispersion significantly (P < 0.002) decreased in patients without events It was revealed with linear regression and correlation analy- sis that the degree of and the changes in P-maximum and P-wave dispersion were correlated with devel- opment of late cardiac events after PMBV, with Cut-off values of ≥62.8 msec for P-wave dispersion and 118 mes for P-maximum.ROC curve showed AUC of 0.919 for P-wave dispersion and 0.913 for P-maximum (P < 0.001). Conclusion: P-wave maximum and dispersion are significantly increased in patients with mitral stenosis. These changes decreased significantly after PMBV. The P-maximum and P-wave dispersion changes were correlated with significant impairment of right dysfunction and the degree of pulmonary artery pressure. P-maximum and P-wave dispersion could be considered as independent predictors of late outcome of patients with MS after successful PMBV (AF, recurrent hospital admission, embolic phenomenon deterioration of right ventricular function).展开更多
A superposing principle, by suitably adding the strain waves from a number of concentrated explosive charges to approximate the waves generated by a cylindrical charge based on the strain wave of a point or small sphe...A superposing principle, by suitably adding the strain waves from a number of concentrated explosive charges to approximate the waves generated by a cylindrical charge based on the strain wave of a point or small spherical explosive charge generated in rock, is used to further study the triggering time of strain gauges installed in radial direction at same distances but different positions surrounding a cylindrical explosive charge in rock. The duration of the first compression phase and peak value of strain wave, and furthermore, their differences are analyzed and some explanations are given. Besides that, the gauge orientation in which the maximum peak value occurs is also discussed. At last, the effect of velocity of detonation(V.O.D.) of a cylindrical explosive charge on the strain waves generated in the surrounding rock is taken as key research and the pattern of peak amplitude of a strain wave varies with the V.O.D. is likely to have been found.展开更多
Among the geotechnical in situ tests,the dynamic penetration test(DPT)is commonly used around the world.However,DPT remains a rough technique and provides only one failure parameter:blow count or cone resistance.This ...Among the geotechnical in situ tests,the dynamic penetration test(DPT)is commonly used around the world.However,DPT remains a rough technique and provides only one failure parameter:blow count or cone resistance.This paper presents an improvement of the dynamic cone penetration test(DCPT)for soil characterisation based on the wave equation theory.Implemented on an instrumented lightweight dynamic penetrometer driving with variable energy,the main process of the test involves the separation and reconstruction of the waves propagating in the rods after each blow and provides a dynamic cone load-penetration(DCLT)curve.An analytical methodology is used to analyse this curve and to estimate additional strength and deformation parameters of the soil:dynamic and pseudo-static cone resistances,deformation modulus and wave velocity.Tests carried out in the laboratory on different specimens(wood,concrete,sand and clay)in an experimental sand pit and in the field demonstrated that the resulting DCLT curve is reproducible,sensitive and reliable to the test conditions(rod length,driving energy,etc.)as well as to the soil properties(nature,density,etc.).Obtained results also showed that the method based on shock polar analysis makes it possible to evaluate mechanical impedance and wave velocity of soils,as demonstrated by the comparisons with cone penetration test(CPT)and shear wave velocity measurements made in the field.This technique improves the method and interpretation of DPT and provides reliable data for shallow foundation design.展开更多
A simultaneous inversion of earthquake relocation and three-dimensional crustal structure of P-wave velocity in central-western China (21癗~36癗, 98癊~112癊) were performed in this paper. The crustal P-wave velocity m...A simultaneous inversion of earthquake relocation and three-dimensional crustal structure of P-wave velocity in central-western China (21癗~36癗, 98癊~112癊) were performed in this paper. The crustal P-wave velocity model and earthquake relocation for this region are obtained using Pg and Sg phase readings of 9 988 earthquakes from 1992 to 1999 recorded at 193 seismic stations within central-western China by SPHYPIT90 and SPHREL3D90 programs. A lateral inhomogeneous structure of P-wave velocity in this region was obtained. Ob-vious contrast of P-wave velocities was revealed on both sides of active fault zones. Relocated epicenters of 6 459 events show clear lineation along active faults, which indicated a close correlation between seismicity and the active faults in this region. Focal depths of 82% relocated events ranged from 0 to 20 km, which is in good agreement with that from double-difference earthquake location algorithm.展开更多
In order to get the 3-D fine velocity structure in the Capital-circle area of China, 6 explosions, ranging from 1800 to 2500 kg, were conducted and recorded by an array of 240 seismographs. A reflection/refraction su...In order to get the 3-D fine velocity structure in the Capital-circle area of China, 6 explosions, ranging from 1800 to 2500 kg, were conducted and recorded by an array of 240 seismographs. A reflection/refraction survey was carried out along the profile extending from Anxin county, Hebei Province northeastward to Yanshan Mountains, crossing the Zhangjiakou-Bohai tectonic zone. The 2-D velocity structure of P wave was imaging along the profile. The results show that abnormality exists in the deep structure of the Zhangjiakou-Bohai tectonic zone: The base- ment is significantly depressed, the interfaces and Moho are uplifted, and a strong velocity gradient layer is existed above the Moho that may be dislocated by deep fault. The crust of Huabei basin is thin and low velocity body ex- ists in the crust. The Yanshan Mountains′ crust is thick, the layers in the crust are quite clear and the velocity in the layer is homogeneous. Huabei basin differs from Yanshan Mountains in structure.展开更多
BACKGROUND： Activation of the sympathetic nervous system plays an important role in regulating cardiovascular actions. P wave parameters can provide general information on central cardiovascular autonomic regulatory ...BACKGROUND： Activation of the sympathetic nervous system plays an important role in regulating cardiovascular actions. P wave parameters can provide general information on central cardiovascular autonomic regulatory responses, which are altered in patients with anxiety disorders and depression. In particular, there are no reports addressing changes in P wave duration and dispersion. OBJECTIVE： To compare the differences in P wave duration and P wave dispersion between patients with anxiety disorders and depression, because patients with anxiety disorders and depression develop abnormal electrocardiograms. DESIGN, TIME AND SETTING： A non-randomized concurrent controlled study was performed. Patients with depression and general anxiety disorders were admitted at the psychiatry outpatient clinics of the Medical Faculty of Duezce University of Turkey between May 2005 and October 2006. PARTICIPANTS： A total of 71 consecutive patients with depression and anxiety disorders, as well as 50 physically and mentally healthy age- and gender-matched controls were selected. METHODS： Electrocardiogram records were obtained at the time of admission to the outpatient clinics. MAIN OUTCOME MEASURES： P wave duration and P wave dispersion were measured. RESULTS： Both the maximum （Prnax） and minimum （Pmin） P wave duration were greater in patients with psychiatric disorders than in healthy controls. Pmax was significantly greater in patients with depression or anxiety disorders （Bonferroni test, P 〈 0.017）. The P wave dispersion was similar between patients and controls （P 〉 0.017）. P waves were similar between panic patients and other anxiety patients. Beck depression results were positively correlated with Prawn and Prnax （r= 0.374, 0.302, P = 0.013, 0.049, respectively）, and not associated with P wave dispersion （P 〉 0.05）. CONCLUSION： Psychiatric disorders are associated with increases in Prnax, but not with P wave dispersion. The P wave changes were associated with the degree of depression.展开更多
It becomes increasingly clear that non-uniform distribution of immiscible fluids in porous rock is particularly relevant to seismic wave dispersion. White proposed a patchy saturation model in 1975, in which spherical...It becomes increasingly clear that non-uniform distribution of immiscible fluids in porous rock is particularly relevant to seismic wave dispersion. White proposed a patchy saturation model in 1975, in which spherical gas pockets were located at the center of a liquid saturated cube. For an extremely light and compressible inner gas, the physical properties can be approximated by a vacuum with White＇s model. The model successfully analyzes the dispersion phenomena of a P-wave velocity in gas-water- saturated rocks. In the case of liquid pocket saturation, e.g., an oil-pocket surrounded by a water saturated host matrix, the light fluid-pocket assumption is doubtful, and few works have been reported in White＇s framework. In this work, Poisson＇s ratio, the bulk modulus, and the effective density of a dual-liquid saturated medium are formulated for the heterogeneous porous rocks containing liquid-pockets. The analysis of the difference between the newly derived bulk modulus and that of White＇s model shows that the effects of liquid-pocket saturation do not disappear unless the porosity approaches zero. The inner pocket fluid can no longer be ignored. The improvements of the P-wave velocity predictions are illustrated with two examples taken from experiments, i.e., the P-wave velocity in the sandstone saturated by oil and brine and the P-wave velocity for heavy oils and stones at different temperatures.展开更多
Dispersion and attenuation occur while seismic wave travels through cracks filled with fluids,which lead to the anisotropism of seismic azimuthal travel time.Based on latest rock physics models,this study aims to simu...Dispersion and attenuation occur while seismic wave travels through cracks filled with fluids,which lead to the anisotropism of seismic azimuthal travel time.Based on latest rock physics models,this study aims to simulate seismic azimuthal moveout responses(AMR) and analyze the factors affecting this attribute.By numerical modeling,it is found that the AMR is very sensitive to the parameters of the cracks,especially these related to fluid;therefore AMR has the potential to qualitatively or even quantitatively identify cracks.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
基金supported by the National Science Council of Taiwan granted NSC-94-2816-M-194-004
文摘Based on the measurement of the arrival time of maxima magnitude from band-pass filtering signals which were determined using a new Morlet wavelet multiple-filter method, we develop a method for measuring intrinsic and attenuative dispersion of the first cycle direct P-wave. We determine relative group delays of spectral components of direct P-waves for 984 ray paths from SML and ALS stations of the Taiwan Central Weather Bureau Seismic Network （CWBSN）. Using continuous relaxation model, we deduce a new transfer function that relates intrinsic dispersion to attenuation. Based on the genetic algorithm （GA）, we put forward a new inversion procedure for determining which is defined the flat part of quality factor Q（ω） spectrum, τ1 and τ2 parameters. The results indicate that ① The distribution of Om values versus epicentral distance and depth show that Qm values linearly increase with increasing of epicentral distance and depth, and Qm values is clearly independent of earthquakes magnitude; ② In the different depth ranges, Qm residual show no correlation with variations in epicentral distance. Some significant changes of Qm residual with time is likely caused by pre-seismic stress accumulation, and associated with fluid-filled higher density fractures rock volume in the source area of 1999 Chi-Chi Taiwan earthquake. We confirm that Qm residual with time anomaly appears about 2.5 years before the Chi-Chi earthquake; ③ A comparison of Qm residual for different depth range between SML and ALS stations show that the level of stress has vertical and lateral difference; ④ The area near observation station with both anomalously increasing and decreasing averaged Qm residual is likely an unstable environment for future strong earthquake occurrence. This study demonstrates the capability of direct P-waves dispersion for monitoring attenuation characteristics and its state changes of anelastic medium of the Earth at short propagation distance using seismograms recorded from very small events.
文摘AIM:To investigate the P wave dispersion as a non-invasive marker of intra-atrial conduction disturbances in patients with Wilson's disease. METHODS:We compared Wilson's disease patients (n = 18) with age matched healthy subjects (n = 15) as controls. The diagnosis was based on clinical symptoms, laboratory tests (ceruloplasmin, urinary and hepatic copper concentrations). P wave dispersion, a measurement of the heterogeneity of atrial depolarization, was measured as the difference between the duration of the longest and the shortest P-waves in 12 lead electrocardiography. RESULTS:All the patients were asymptomatic on cardiological examination and have sinusal rhythm in electrocardiography. Left ventricular and left atrial diameters, left ventricular ejection fraction and left ventricular mass index were similar in both groups. The Wilson's disease patients had a significantly higher P wave dispersion compared with the controls (44.7 ± 5.8 vs 25.7 ± 2.5, P < 0.01). CONCLUSION:There was an increase in P wave dispersion in cardiologically asymptomatic Wilson's disease patients which probably represents an early stage of cardiac involvement.
基金Key Project Process Mechanism and Prediction of Geological Hazards (2001CB711005-1-3) and State Key Basic Research Project Mechanism and Prediction of Continental Earthquakes (G1998040702). sponsored by the Ministry of Science and Techno
基金The special project of Detection of Haikou City Earthquake Active Faults from the Tenth Five-year Plan of China Earthquake Administration (0106512)Joint Seismological Science Foundation of China (105086)CAS Key Laboratory of Marginal Sea Geology (MSGL0503).
文摘Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions has been determined. The results show that the pattern of velocity anomalies in the shallower upper crust is somewhat associated with the surface geological tectonics in the region. A relative low-velocity anomaly appears north of the Wangwu-Wenjiao fault zone and a relative high-velocity anomaly appears south of the Wangwu-Wenjiao fault zone,corresponding to the depressed areas in north Hainan Island,where many volcanoes are frequently active and geothermal values are relatively higher,and the uplifted and stable regions in central and south of the Hainan Is-land. In the middle and lower crust velocities are relatively lower in east Hainan than those in west Hainan,possi-bly suggesting the existence of the upwelling of hot materials from the mantle in east Hainan. The pattern of veloc-ity anomalies also indicates that NW faults,i.e.,the Puqian-Qinglan fault,may be shallower,while the E-W Wangwu-Wenjiao fault may be deeper,which perhaps extends down to Moho depth or deeper.
文摘Objective: The aim of the study was to investigate the impact of P-maximum and P-wave dispersion on the long term clinical outcome after successful percutaneous balloon mitral valvuloplasty (PBMV) in patients with mitral stenosis (MS) and sinus rhythm. Also to test the correlation between P-variables and right ventricular function and pulmonary artery pressure before and after PMBV. Methods: Eighty-five patients undergoing PMBV were enrolled in this study. We evaluated P-maximum, P-minimum and P-wave dispersion before and one month after PBMV. We studied the changes in pulmonary arterial pressure (PAP), left atrial (LA) dimension, mitral diastolic gradient, and mitral valve area, in addition to the changes in right ventricular function utilizing tissue Doppler assessment both before and after PMBV, in addition the role of the P-wave dispersion in predicttion of late cardiac events. Results: There were significant decreases in mean diastolic gradient, PAP, and LA size and significant improvement in right ventricular tissue Doppler indices after PMBV. Ac- company these hemodynamic changes after PMBV. P-maximum and P-wave dispersion were found to be decreased (P < 0.001). Patients developed cardiac events during follow-up had a higher P-maximum and P-dispersion than those without late cardiac events (P < 0.001). Moreover the changes in P-maxi- mum and P-dispersion before and after PMBV in patients with cardiac events were not significant, while P-maximum and P-dispersion significantly (P < 0.002) decreased in patients without events It was revealed with linear regression and correlation analy- sis that the degree of and the changes in P-maximum and P-wave dispersion were correlated with devel- opment of late cardiac events after PMBV, with Cut-off values of ≥62.8 msec for P-wave dispersion and 118 mes for P-maximum.ROC curve showed AUC of 0.919 for P-wave dispersion and 0.913 for P-maximum (P < 0.001). Conclusion: P-wave maximum and dispersion are significantly increased in patients with mitral stenosis. These changes decreased significantly after PMBV. The P-maximum and P-wave dispersion changes were correlated with significant impairment of right dysfunction and the degree of pulmonary artery pressure. P-maximum and P-wave dispersion could be considered as independent predictors of late outcome of patients with MS after successful PMBV (AF, recurrent hospital admission, embolic phenomenon deterioration of right ventricular function).
基金Projects(51304239,51374243)supported by the National Natural Science Foundation of China
文摘A superposing principle, by suitably adding the strain waves from a number of concentrated explosive charges to approximate the waves generated by a cylindrical charge based on the strain wave of a point or small spherical explosive charge generated in rock, is used to further study the triggering time of strain gauges installed in radial direction at same distances but different positions surrounding a cylindrical explosive charge in rock. The duration of the first compression phase and peak value of strain wave, and furthermore, their differences are analyzed and some explanations are given. Besides that, the gauge orientation in which the maximum peak value occurs is also discussed. At last, the effect of velocity of detonation(V.O.D.) of a cylindrical explosive charge on the strain waves generated in the surrounding rock is taken as key research and the pattern of peak amplitude of a strain wave varies with the V.O.D. is likely to have been found.
文摘Among the geotechnical in situ tests,the dynamic penetration test(DPT)is commonly used around the world.However,DPT remains a rough technique and provides only one failure parameter:blow count or cone resistance.This paper presents an improvement of the dynamic cone penetration test(DCPT)for soil characterisation based on the wave equation theory.Implemented on an instrumented lightweight dynamic penetrometer driving with variable energy,the main process of the test involves the separation and reconstruction of the waves propagating in the rods after each blow and provides a dynamic cone load-penetration(DCLT)curve.An analytical methodology is used to analyse this curve and to estimate additional strength and deformation parameters of the soil:dynamic and pseudo-static cone resistances,deformation modulus and wave velocity.Tests carried out in the laboratory on different specimens(wood,concrete,sand and clay)in an experimental sand pit and in the field demonstrated that the resulting DCLT curve is reproducible,sensitive and reliable to the test conditions(rod length,driving energy,etc.)as well as to the soil properties(nature,density,etc.).Obtained results also showed that the method based on shock polar analysis makes it possible to evaluate mechanical impedance and wave velocity of soils,as demonstrated by the comparisons with cone penetration test(CPT)and shear wave velocity measurements made in the field.This technique improves the method and interpretation of DPT and provides reliable data for shallow foundation design.
文摘A simultaneous inversion of earthquake relocation and three-dimensional crustal structure of P-wave velocity in central-western China (21癗~36癗, 98癊~112癊) were performed in this paper. The crustal P-wave velocity model and earthquake relocation for this region are obtained using Pg and Sg phase readings of 9 988 earthquakes from 1992 to 1999 recorded at 193 seismic stations within central-western China by SPHYPIT90 and SPHREL3D90 programs. A lateral inhomogeneous structure of P-wave velocity in this region was obtained. Ob-vious contrast of P-wave velocities was revealed on both sides of active fault zones. Relocated epicenters of 6 459 events show clear lineation along active faults, which indicated a close correlation between seismicity and the active faults in this region. Focal depths of 82% relocated events ranged from 0 to 20 km, which is in good agreement with that from double-difference earthquake location algorithm.
基金Preliminary study of State Key Basic Research Project (2001CCA02100) and National Natural Science Foundation of China (40234038).
文摘In order to get the 3-D fine velocity structure in the Capital-circle area of China, 6 explosions, ranging from 1800 to 2500 kg, were conducted and recorded by an array of 240 seismographs. A reflection/refraction survey was carried out along the profile extending from Anxin county, Hebei Province northeastward to Yanshan Mountains, crossing the Zhangjiakou-Bohai tectonic zone. The 2-D velocity structure of P wave was imaging along the profile. The results show that abnormality exists in the deep structure of the Zhangjiakou-Bohai tectonic zone: The base- ment is significantly depressed, the interfaces and Moho are uplifted, and a strong velocity gradient layer is existed above the Moho that may be dislocated by deep fault. The crust of Huabei basin is thin and low velocity body ex- ists in the crust. The Yanshan Mountains′ crust is thick, the layers in the crust are quite clear and the velocity in the layer is homogeneous. Huabei basin differs from Yanshan Mountains in structure.
文摘BACKGROUND： Activation of the sympathetic nervous system plays an important role in regulating cardiovascular actions. P wave parameters can provide general information on central cardiovascular autonomic regulatory responses, which are altered in patients with anxiety disorders and depression. In particular, there are no reports addressing changes in P wave duration and dispersion. OBJECTIVE： To compare the differences in P wave duration and P wave dispersion between patients with anxiety disorders and depression, because patients with anxiety disorders and depression develop abnormal electrocardiograms. DESIGN, TIME AND SETTING： A non-randomized concurrent controlled study was performed. Patients with depression and general anxiety disorders were admitted at the psychiatry outpatient clinics of the Medical Faculty of Duezce University of Turkey between May 2005 and October 2006. PARTICIPANTS： A total of 71 consecutive patients with depression and anxiety disorders, as well as 50 physically and mentally healthy age- and gender-matched controls were selected. METHODS： Electrocardiogram records were obtained at the time of admission to the outpatient clinics. MAIN OUTCOME MEASURES： P wave duration and P wave dispersion were measured. RESULTS： Both the maximum （Prnax） and minimum （Pmin） P wave duration were greater in patients with psychiatric disorders than in healthy controls. Pmax was significantly greater in patients with depression or anxiety disorders （Bonferroni test, P 〈 0.017）. The P wave dispersion was similar between patients and controls （P 〉 0.017）. P waves were similar between panic patients and other anxiety patients. Beck depression results were positively correlated with Prawn and Prnax （r= 0.374, 0.302, P = 0.013, 0.049, respectively）, and not associated with P wave dispersion （P 〉 0.05）. CONCLUSION： Psychiatric disorders are associated with increases in Prnax, but not with P wave dispersion. The P wave changes were associated with the degree of depression.
基金Project supported by the Open Foundation of SINOPEC Key Laboratory of Geophysics(No.WTYJY-WX2013-04-02)the National Key Basic Research Program of China(973 Program)(No.2014CB239006)the 12th 5-Year Basic Research Program of China National Packaging Corporation(CNPC)(No.2014A-3611)
文摘It becomes increasingly clear that non-uniform distribution of immiscible fluids in porous rock is particularly relevant to seismic wave dispersion. White proposed a patchy saturation model in 1975, in which spherical gas pockets were located at the center of a liquid saturated cube. For an extremely light and compressible inner gas, the physical properties can be approximated by a vacuum with White＇s model. The model successfully analyzes the dispersion phenomena of a P-wave velocity in gas-water- saturated rocks. In the case of liquid pocket saturation, e.g., an oil-pocket surrounded by a water saturated host matrix, the light fluid-pocket assumption is doubtful, and few works have been reported in White＇s framework. In this work, Poisson＇s ratio, the bulk modulus, and the effective density of a dual-liquid saturated medium are formulated for the heterogeneous porous rocks containing liquid-pockets. The analysis of the difference between the newly derived bulk modulus and that of White＇s model shows that the effects of liquid-pocket saturation do not disappear unless the porosity approaches zero. The inner pocket fluid can no longer be ignored. The improvements of the P-wave velocity predictions are illustrated with two examples taken from experiments, i.e., the P-wave velocity in the sandstone saturated by oil and brine and the P-wave velocity for heavy oils and stones at different temperatures.
基金Supported by Project of National Natural Science Foundation of China(No.40874057)
文摘Dispersion and attenuation occur while seismic wave travels through cracks filled with fluids,which lead to the anisotropism of seismic azimuthal travel time.Based on latest rock physics models,this study aims to simulate seismic azimuthal moveout responses(AMR) and analyze the factors affecting this attribute.By numerical modeling,it is found that the AMR is very sensitive to the parameters of the cracks,especially these related to fluid;therefore AMR has the potential to qualitatively or even quantitatively identify cracks.
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。
