This paper reviews the geometric resistivity correction factor of the 4-point probe DC electrical conduc- tivity measurement method using several geometrical samples. During the review of the literature, only the arti...This paper reviews the geometric resistivity correction factor of the 4-point probe DC electrical conduc- tivity measurement method using several geometrical samples. During the review of the literature, only the articles that include the effect of geometry on resistivity calculation were considered. Combinations of equations used for various geometries were also given. Mathematical equations were given in the text without details. Expressions for the most commonly used geometries were presented in a table for easy reference.展开更多
For reservoirs with abnormally high pressure and high geostress,formation resistivity can be greatly affected.This increase of resistivity resulting from high stress causes errors in the identification of reservoir fl...For reservoirs with abnormally high pressure and high geostress,formation resistivity can be greatly affected.This increase of resistivity resulting from high stress causes errors in the identification of reservoir fluids.In order to investigate the effect of stress on resistivity,resistivity measurement was conducted simultaneously with triaxial testing to obtain rock resistivity under high temperature and high pressure.The changes of resistivity and resistivity increasing coefficient with horizontal differential stress and minimum horizontal stress were revealed from experiments.Besides,field data were analyzed to show the main influencing factors of formation resistivity under reservoir conditions.In addition,a new resistivity correction model for high geostress formation was derived in this work.The interpretation results are in good agreement with well testing data in the Keshen area of the Tarim oilfield,China.展开更多
The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless ...The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.展开更多
Energy calibration of resistive charge division-based position-sensitive silicon detectors is achieved by parabolic fitting in the traditional method, where the systematic variations of vertex and curvature of the par...Energy calibration of resistive charge division-based position-sensitive silicon detectors is achieved by parabolic fitting in the traditional method, where the systematic variations of vertex and curvature of the parabola with energy must be considered. In this paper we extend the traditional method in order to correct the fitting function, simplify the procedure of calibration and improve the experimental data quality. Instead of a parabolic function as used in the traditional method, a new function describing the relation of position and energy is introduced.The energy resolution of the 8.088 Me V α decay of213 Rn is determined to be about 87 ke V（FWHM）, which is better than the result of the traditional method, 104 ke V（FWHM）. The improved method can be applied to the energy calibration of resistive charge division-based position-sensitive silicon detectors with various performances.展开更多
文摘This paper reviews the geometric resistivity correction factor of the 4-point probe DC electrical conduc- tivity measurement method using several geometrical samples. During the review of the literature, only the articles that include the effect of geometry on resistivity calculation were considered. Combinations of equations used for various geometries were also given. Mathematical equations were given in the text without details. Expressions for the most commonly used geometries were presented in a table for easy reference.
文摘For reservoirs with abnormally high pressure and high geostress,formation resistivity can be greatly affected.This increase of resistivity resulting from high stress causes errors in the identification of reservoir fluids.In order to investigate the effect of stress on resistivity,resistivity measurement was conducted simultaneously with triaxial testing to obtain rock resistivity under high temperature and high pressure.The changes of resistivity and resistivity increasing coefficient with horizontal differential stress and minimum horizontal stress were revealed from experiments.Besides,field data were analyzed to show the main influencing factors of formation resistivity under reservoir conditions.In addition,a new resistivity correction model for high geostress formation was derived in this work.The interpretation results are in good agreement with well testing data in the Keshen area of the Tarim oilfield,China.
文摘The utilization of position sensor reduces the system reliability of switched reluctance motor(SRM),especially in harsh environments.It also increases the complexity of the system.Therefore,the research on sensorless control has become one of the hot spots in recent years.Comparing with the existing sensorless control technology,the new method exploring the sensorless control of double-sided linear switched reluctance motor(DLSRM)shows the following advantages:1)high accuracy,and 2)good practicability.Based on the new proposed method,the DLSRM speed controller is augmented with the peak current method and the voltage chopping closed-loop speed control.Moreover,the winding resistance in the equation is corrected according to the integral flux linkage when the phase current is zero.The accuracy and feasibility of the simplified flux linkage method in estimating the position of the DLSRM is verified.
基金Supported by ‘100 Person Project’ of the Chinese Academy of Sciencesthe National Natural Science Foundation of China(11405224 and 11435014)
文摘Energy calibration of resistive charge division-based position-sensitive silicon detectors is achieved by parabolic fitting in the traditional method, where the systematic variations of vertex and curvature of the parabola with energy must be considered. In this paper we extend the traditional method in order to correct the fitting function, simplify the procedure of calibration and improve the experimental data quality. Instead of a parabolic function as used in the traditional method, a new function describing the relation of position and energy is introduced.The energy resolution of the 8.088 Me V α decay of213 Rn is determined to be about 87 ke V（FWHM）, which is better than the result of the traditional method, 104 ke V（FWHM）. The improved method can be applied to the energy calibration of resistive charge division-based position-sensitive silicon detectors with various performances.
