When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI (Horizontal Transve...When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI (Horizontal Transverse Isotropy) formation can be determined. The method of calculating the fast and slow wave data when a shear wave propagates along the borehole axis in anisotropic formation was analyzed, and the implementation of a cross-dipole acoustic logging tool was demonstrated. The tool was composed of transmitter electronics, transmitter mandrel, acoustic isolator, receiver mandrel and main control electronics. Sonde, transmitter circuit, signal receiving and processing circuit, data acquisition system, system control circuit and telemetry interface circuit were presented and analyzed. The test model was used in production wells and standard wells in various areas and the four-component cross-dipole waves were acquired and processed. The waves had good signal-to-noise ratio and clear characteristics, and the fast and slow waveforms, processed slowness curves, anisotropy and fast shear wave azimuth well matched with each other.展开更多
The response characteristics of the dual-induction logging tool while drilling in a half-spaceare computed and analyzed when the instrument slots opening direction, instrument height, ground conductivity is changed re...The response characteristics of the dual-induction logging tool while drilling in a half-spaceare computed and analyzed when the instrument slots opening direction, instrument height, ground conductivity is changed respectively. The results show that the haJ^-space response of the different opening direction of instrument slots has a nonlinear change with the increase of the ground conductivity. The effect of half-space response on the instrument slots downward opening direction is greatest and the upward is minimal The half-space response of the deep induction reaches the maximum near the 0.4m height when tool is above ground. The peak position does not change with the ground conductivity changes.These results have a practical significance to determine accurately the sonde error of the dual-induction logging tool while drilling.展开更多
This study undertook verification of the applicability and accuracy of wind data measured using a WindCube V2 Doppler Wind Lidar(DWL).The data were collected as part of a field experiment in Zhoushan,Zhejiang Province...This study undertook verification of the applicability and accuracy of wind data measured using a WindCube V2 Doppler Wind Lidar(DWL).The data were collected as part of a field experiment in Zhoushan,Zhejiang Province(China),which was conducted by Shanghai Typhoon Institute of China Meteorological Administration during the passage of Super Typhoon Lekima(2019).The DWL measurements were compared with balloon-borne GPS radiosonde(GPS sonde)data,which were acquired using balloons launched from the DWL location.Results showed that wind speed measured by GPS sonde at heights of<100 m is unreliable owing to the drift effect.Optimal agreement(at heights of>100 m)was found for DWL-measured wind speed time-averaged during the ascent of the GPS sonde from the ground surface to the height of 270 m(correlation coefficient:0.82;root mean square(RMS):2.19 m·h^(-1)).Analysis revealed that precipitation intensity(PI)exerts considerable influence on both the carrier-to-noise ratio and the rate of missing DWL data;however,PI has minimal effect on the wind speed bias of DWL measurements.Specifically,the rate of missing DWL data increased with increasing measurement height and PI.For PI classed as heavy rain or less(PI<12 mm·h^(-1)),the DWL data below 300 m were considered valid,whereas for PI classed as a severe rainstorm(PI>90 m·h^(-1)),only data below 100 m were valid.Up to the height of 300 m,the RMS of the DWL measurements was nearly half that of wind profile radar(WPR)estimates(4.32 m·s^(-1)),indicating that DWL wind data are more accurate than WPR data under typhoon conditions.展开更多
OBJECTIVE:To evaluates the antioxidant and hepatoprotective potentials of Dicoma anomala Sond.(Asteraceae) on body weight,feed and water intake,biochemical parameters and organ histology.METHODS:Various concentrations...OBJECTIVE:To evaluates the antioxidant and hepatoprotective potentials of Dicoma anomala Sond.(Asteraceae) on body weight,feed and water intake,biochemical parameters and organ histology.METHODS:Various concentrations(1.56-25 μg/m L)were used in the in vitro assays 1,1-diphenyl-2-picryl hydrazyl(DPPH,superoxide anion,hydroxyl radicals,etc.).The effects of treatment with 125,250 and 250 mg/m L Dicoma anomala aqueous roots extract(DARE) was investigated in vivo in the CCl4-induced hepatotoxic rats during the 15 days study.RESULTS:Water extract exhibited the best activity(IC50:15.20 ± 0.03,11.70 ± 0.10,and 0.84 ± 0.05 μg/m L) in vitro in DPPH,hydroxyl and superoxide anion radicals,respectively,when compared with standards.Pre-treatment and treatment with different concentrations of DARE significantly(P < 0.05)attenuated the elevated serum activities of aspartate transaminase,alanine transaminase levels while increasing the activities of superoxide dismutase,catalase and glutathione peroxidase.The histopathological evaluations revealed extensive liver damage characterized by severe vacuolar and cytoplasmic degeneration,hepatic necrosis,and cellular infilteration in pre-treated groups while in the treated groups;such liver damages were not observed most especially at 500 mg/kg dose.CONCLUSION:The results proved the hepatoprotective potential of DARE against CCl4-induced oxidative stress.Moreover,histopathological examinations revealed better therapeutic advantage of DARE than prophylactic use.展开更多
文摘When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI (Horizontal Transverse Isotropy) formation can be determined. The method of calculating the fast and slow wave data when a shear wave propagates along the borehole axis in anisotropic formation was analyzed, and the implementation of a cross-dipole acoustic logging tool was demonstrated. The tool was composed of transmitter electronics, transmitter mandrel, acoustic isolator, receiver mandrel and main control electronics. Sonde, transmitter circuit, signal receiving and processing circuit, data acquisition system, system control circuit and telemetry interface circuit were presented and analyzed. The test model was used in production wells and standard wells in various areas and the four-component cross-dipole waves were acquired and processed. The waves had good signal-to-noise ratio and clear characteristics, and the fast and slow waveforms, processed slowness curves, anisotropy and fast shear wave azimuth well matched with each other.
文摘The response characteristics of the dual-induction logging tool while drilling in a half-spaceare computed and analyzed when the instrument slots opening direction, instrument height, ground conductivity is changed respectively. The results show that the haJ^-space response of the different opening direction of instrument slots has a nonlinear change with the increase of the ground conductivity. The effect of half-space response on the instrument slots downward opening direction is greatest and the upward is minimal The half-space response of the deep induction reaches the maximum near the 0.4m height when tool is above ground. The peak position does not change with the ground conductivity changes.These results have a practical significance to determine accurately the sonde error of the dual-induction logging tool while drilling.
基金supported by the National Key R&D Program of China(No.2018YFB1501104)Key Program for International S&T Cooperation Projects of China(No.2017YFE0107700)+1 种基金National Natural Science Foundation of China(Grant No.41805088)Natural Science Foundation of Shanghai(No.18ZR1449100).
文摘This study undertook verification of the applicability and accuracy of wind data measured using a WindCube V2 Doppler Wind Lidar(DWL).The data were collected as part of a field experiment in Zhoushan,Zhejiang Province(China),which was conducted by Shanghai Typhoon Institute of China Meteorological Administration during the passage of Super Typhoon Lekima(2019).The DWL measurements were compared with balloon-borne GPS radiosonde(GPS sonde)data,which were acquired using balloons launched from the DWL location.Results showed that wind speed measured by GPS sonde at heights of<100 m is unreliable owing to the drift effect.Optimal agreement(at heights of>100 m)was found for DWL-measured wind speed time-averaged during the ascent of the GPS sonde from the ground surface to the height of 270 m(correlation coefficient:0.82;root mean square(RMS):2.19 m·h^(-1)).Analysis revealed that precipitation intensity(PI)exerts considerable influence on both the carrier-to-noise ratio and the rate of missing DWL data;however,PI has minimal effect on the wind speed bias of DWL measurements.Specifically,the rate of missing DWL data increased with increasing measurement height and PI.For PI classed as heavy rain or less(PI<12 mm·h^(-1)),the DWL data below 300 m were considered valid,whereas for PI classed as a severe rainstorm(PI>90 m·h^(-1)),only data below 100 m were valid.Up to the height of 300 m,the RMS of the DWL measurements was nearly half that of wind profile radar(WPR)estimates(4.32 m·s^(-1)),indicating that DWL wind data are more accurate than WPR data under typhoon conditions.
基金Supported by Research committee,University of the Free State,Qwaqwa campus,(entity No.211427604)Free State,SA
文摘OBJECTIVE:To evaluates the antioxidant and hepatoprotective potentials of Dicoma anomala Sond.(Asteraceae) on body weight,feed and water intake,biochemical parameters and organ histology.METHODS:Various concentrations(1.56-25 μg/m L)were used in the in vitro assays 1,1-diphenyl-2-picryl hydrazyl(DPPH,superoxide anion,hydroxyl radicals,etc.).The effects of treatment with 125,250 and 250 mg/m L Dicoma anomala aqueous roots extract(DARE) was investigated in vivo in the CCl4-induced hepatotoxic rats during the 15 days study.RESULTS:Water extract exhibited the best activity(IC50:15.20 ± 0.03,11.70 ± 0.10,and 0.84 ± 0.05 μg/m L) in vitro in DPPH,hydroxyl and superoxide anion radicals,respectively,when compared with standards.Pre-treatment and treatment with different concentrations of DARE significantly(P < 0.05)attenuated the elevated serum activities of aspartate transaminase,alanine transaminase levels while increasing the activities of superoxide dismutase,catalase and glutathione peroxidase.The histopathological evaluations revealed extensive liver damage characterized by severe vacuolar and cytoplasmic degeneration,hepatic necrosis,and cellular infilteration in pre-treated groups while in the treated groups;such liver damages were not observed most especially at 500 mg/kg dose.CONCLUSION:The results proved the hepatoprotective potential of DARE against CCl4-induced oxidative stress.Moreover,histopathological examinations revealed better therapeutic advantage of DARE than prophylactic use.