A unique method for preparing a coaxial dual-microelectrode sensor by vaporizing the nano-thickness Au layer on the DNA modified carbon fiber micro-column electrode was illustrated. The dual-electrode showed particula...A unique method for preparing a coaxial dual-microelectrode sensor by vaporizing the nano-thickness Au layer on the DNA modified carbon fiber micro-column electrode was illustrated. The dual-electrode showed particular merit for determination in biological systems.展开更多
The accurate measurement of volume fraction of oil-water two-phase flow on line is important in the oil field.This paper presents a new coaxial conductivity sensor for measuring the volume fraction of oil-water two-ph...The accurate measurement of volume fraction of oil-water two-phase flow on line is important in the oil field.This paper presents a new coaxial conductivity sensor for measuring the volume fraction of oil-water two-phase flow.This structure may get the more uniform sensitivity field and the vertical installation may get the more axial symmetry of the flow field,which improve the measurement accuracy.In order to minimize the influence of the edge effect,guard electrodes were designed.An anti-edge effect degree Ae was defined to optimize the length of the guard electrode.Different models of effective conductivity of two materials were used in calculating the oil volume fraction of oil-water two-phase flow.The experimental results indicate that Maxwell model is the best model under the condition of oil volume fraction less than 50%and the mean value of the calculation results using Maxwell model and Bruggeman model possesses higher accuracy in the range of oil volume fraction(50%-70%).The experimental results show that the sensor obtains similar measurement performance in both vertical upward and downward flow conditions.The accuracy of the sensor system is 2%when the oil volume fraction less than 50%,and the accuracy is about 5%when the oil volume fraction between 50%and 70%.展开更多
Under nanosecond pulsed coaxial electric field, surface flashover voltage over the interfaces between nylon 1010 and transformer oil increases almost linearly with gap length, and the steeper rising edge of applied pu...Under nanosecond pulsed coaxial electric field, surface flashover voltage over the interfaces between nylon 1010 and transformer oil increases almost linearly with gap length, and the steeper rising edge of applied pulse, the higher flash-over voltage. Surface flashover properties are closely related to the electric field at the triple junctions of solid-liquid-electrode and the field gradient along the interfaces. Although the increased difference between inner and outer electrode radii will enhance electric field strength at the triple junctions and nonuniformity degree of potential distribution along interfaces, it reduces simultaneously terribly the surface field strength of coaxial inner electrode, so that flashover voltage doesn’t descend, but ascends almost linearly with gap length. The average flashover strength in coaxial electric field can be estimated by that in uniform electric field for large enough difference between inner and outer electrode radii, which is useful to practical engineering design for coaxial pulsed power apparatuses.展开更多
目的用自主研发同轴电极和直针式电极电解含百里香酚蓝琼脂-NaCI胶体系统模拟组织毁损,观察两者的电解效应,探讨自主研发同轴电极的应用价值。方法采用百里香酚蓝琼脂-NaCI胶体系统模拟组织。在实验中保持同轴电极和针式电极的接触面积...目的用自主研发同轴电极和直针式电极电解含百里香酚蓝琼脂-NaCI胶体系统模拟组织毁损,观察两者的电解效应,探讨自主研发同轴电极的应用价值。方法采用百里香酚蓝琼脂-NaCI胶体系统模拟组织。在实验中保持同轴电极和针式电极的接触面积、间距一致。随着阴极周围OH-的聚集,pH升高,阴极周围胶体会变为鲜艳的蓝色。将电流分为1.6、5.0、10.0和20 mA 4组进行实验,当电量累积到1、2、4、6、8库仑时测量阴极变色范围。结果在恒定直流电作用下,各电流组同轴电极和针式电极的阴极周围的蓝色量均随电量增加而增加,各组内同轴电极和针式电极间的作用差异无统计学意义(P>0.05)。在给予相同电量时,对各电流组阴极周围的变色体积进行组间比较,差异有统计学意义(P<0.05),即电流越小作用时间越长,变色范围越大。结论自制同轴电极与直针式电极具有相近的电解效果,可以替代直针式电极在电化学治疗中的应用。展开更多
基金The financial support from the NNSFC(No.20173054)is gratefully acknowledged.
文摘A unique method for preparing a coaxial dual-microelectrode sensor by vaporizing the nano-thickness Au layer on the DNA modified carbon fiber micro-column electrode was illustrated. The dual-electrode showed particular merit for determination in biological systems.
基金supported by National Natural Science Foundation of China(Grant No.61072101)Program for New Century Excellent Talents in University(Grant No.NCET-10-0621)the Independent Innovation Foundation of Tianjin University
文摘The accurate measurement of volume fraction of oil-water two-phase flow on line is important in the oil field.This paper presents a new coaxial conductivity sensor for measuring the volume fraction of oil-water two-phase flow.This structure may get the more uniform sensitivity field and the vertical installation may get the more axial symmetry of the flow field,which improve the measurement accuracy.In order to minimize the influence of the edge effect,guard electrodes were designed.An anti-edge effect degree Ae was defined to optimize the length of the guard electrode.Different models of effective conductivity of two materials were used in calculating the oil volume fraction of oil-water two-phase flow.The experimental results indicate that Maxwell model is the best model under the condition of oil volume fraction less than 50%and the mean value of the calculation results using Maxwell model and Bruggeman model possesses higher accuracy in the range of oil volume fraction(50%-70%).The experimental results show that the sensor obtains similar measurement performance in both vertical upward and downward flow conditions.The accuracy of the sensor system is 2%when the oil volume fraction less than 50%,and the accuracy is about 5%when the oil volume fraction between 50%and 70%.
文摘Under nanosecond pulsed coaxial electric field, surface flashover voltage over the interfaces between nylon 1010 and transformer oil increases almost linearly with gap length, and the steeper rising edge of applied pulse, the higher flash-over voltage. Surface flashover properties are closely related to the electric field at the triple junctions of solid-liquid-electrode and the field gradient along the interfaces. Although the increased difference between inner and outer electrode radii will enhance electric field strength at the triple junctions and nonuniformity degree of potential distribution along interfaces, it reduces simultaneously terribly the surface field strength of coaxial inner electrode, so that flashover voltage doesn’t descend, but ascends almost linearly with gap length. The average flashover strength in coaxial electric field can be estimated by that in uniform electric field for large enough difference between inner and outer electrode radii, which is useful to practical engineering design for coaxial pulsed power apparatuses.
文摘目的用自主研发同轴电极和直针式电极电解含百里香酚蓝琼脂-NaCI胶体系统模拟组织毁损,观察两者的电解效应,探讨自主研发同轴电极的应用价值。方法采用百里香酚蓝琼脂-NaCI胶体系统模拟组织。在实验中保持同轴电极和针式电极的接触面积、间距一致。随着阴极周围OH-的聚集,pH升高,阴极周围胶体会变为鲜艳的蓝色。将电流分为1.6、5.0、10.0和20 mA 4组进行实验,当电量累积到1、2、4、6、8库仑时测量阴极变色范围。结果在恒定直流电作用下,各电流组同轴电极和针式电极的阴极周围的蓝色量均随电量增加而增加,各组内同轴电极和针式电极间的作用差异无统计学意义(P>0.05)。在给予相同电量时,对各电流组阴极周围的变色体积进行组间比较,差异有统计学意义(P<0.05),即电流越小作用时间越长,变色范围越大。结论自制同轴电极与直针式电极具有相近的电解效果,可以替代直针式电极在电化学治疗中的应用。
