3D laterolog array sonde design and response simulation

A new three-dimensional laterolog array sonde（3D-LS） is presented. The 3DLS is based on existing high-resolution laterolog array and azimuthal resistivity imaging sondes with radial, longitudinal, and circumferential detection abilities. Six investigation modes are designed using the 3D finite-element method and different investigation depths are simulated based on the pseudo-geometrical factor of the six modes. The invasion profile is described using multi-array radial logs. From the analysis of the pseudo-geometrical factor, the investigation depth of the 3D-LS is about 1.5 m for conductive invasion, which is close to that of the dual laterolog tool but greater than that of the highly integrated azimuthal laterolog sonde. The vertical and azimuthal resolution is also analyzed with the same method. The 3DLS can detect low-resistivity anomalies of 0.5 m thickness and 15？ around the borehole for infinitely thick formations. This study lays the foundation for more work on 3D laterolog array sonde for evaluating low-resistivity anomalies.

Exploring Antarctic subglacial lakes with RECoverable Autonomous Sonde(RECAS):Design and first field tests

Conducting scientific drilling on subglacial lakes and obtaining samples of subglacial lake water holds great significance in unraveling the formation and evolution of Antarctic subglacial lakes and early Earth's life forms.Despite various approaches to access and directly sample subglacial water and sediments,clean access and exploration of subglacial lakes remain challenging.To address this concern,Jilin University has developed the RECoverable Autonomous Sonde(RECAS)prototype.This technology enables sampling and in-situ detection of subglacial lake water while being isolated from the surface,thus minimizing the risk of pollution.Laboratory tests,including downward and upward drilling,long-running,remote-control,and cold-environment assessments,were conducted to validate the sonde's principle and functionality.During the 38th Chinese National Antarctic Research Expedition,CHINARE(2021–2022 season),the RECAS prototype underwent testing on the flank region of Dalk glacier,10 km from Zhongshan Station in Antarctica.Three boreholes with depths of 200.3,183.2,and 133.5 m were successfully drilled,with the refrozen meltwater sealing the boreholes during the process.Approximately 600 mL of melted water samples were collected from each hole.Throughout the drilling tests,all systems of the RECAS prototype performed within the expected ranges.

利用地基GPS资料分析成都地区大气可降水量

利用成都地区GPS地震监测网的观测资料,通过Bernese软件求解获得CHDU、JYAN、PIXI、QLAI、RENS、ZHJI测站的天顶总延迟和湿延迟,运用湿延迟与大气可降水量之间的转换关系得到各测站大气可降水量,与站点地面实际降雨量及SONDE大气可降水量进行了比较分析。结果表明:地基GPS监测大气可降水量变化与地面实际降雨量有很强的相关性,与SONDE大气可降水量的平均差值为0.43 mm,均方偏差为2.56 mm。多站点GPS监测大气可降水量联合分析,对于研究区域大气可降水量的变化有一定的意义。

Design of a cross-dipole array acoustic logging tool

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.

THE HAIF-SPACE RESPONSE ANALYSIS OF DUAL-INDUCTION LOGGING WHILE DRILLING BASED ON COMSOL

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.

大规模集群系统管理应用研究

大规模PC集群的应用和普及对PC集群的管理、维护以及部署提出了新的要求,如何发挥PC集群的效率、降低集群的总体运行成本成为当前需要迫切解决的问题。通过对以SOND架构之上的Bladmin集群管理软件部署和管理大规模集群系统案例的分析,探讨了利用Bladmin技术实现大规模PC集群的优化管理。

Validation of Doppler Wind Lidar during Super Typhoon Lekima (2019)

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.

Antioxidant and hepatoprotective activities of Dicoma anomala Sond.aqueous root extract against carbon tetrachloride-induced liver damage in Wistar rats

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.