一、前言本文介绍笔者设计的一种新型数字化自控系统,它使核磁共振磁强计的系统误差和锁定重复性均优于1×10-7,跟踪速度高达30mT/s,锁定点的温漂小于2×10-7(△B)/B/℃,性能大大超过了模拟自控系统[1][2]。二、工作原理当边...一、前言本文介绍笔者设计的一种新型数字化自控系统,它使核磁共振磁强计的系统误差和锁定重复性均优于1×10-7,跟踪速度高达30mT/s,锁定点的温漂小于2×10-7(△B)/B/℃,性能大大超过了模拟自控系统[1][2]。二、工作原理当边缘振荡器的振荡频率满足核磁共振条件时,共振信号的出现与磁场调制三角波信号fm之间的关系如图1 a 所示,共振信号在时间轴上是等距离分布的。经前置放大后,这个等距分布的信号序列触发单稳态电路,得到脉宽为T/4。展开更多
A method for exact solution to forward degenerate four-wave mixing in transmission geometry for photo refractive media is presented. The effects of pump depletion and light absorption in the nonlinear dynamic media ar...A method for exact solution to forward degenerate four-wave mixing in transmission geometry for photo refractive media is presented. The effects of pump depletion and light absorption in the nonlinear dynamic media are taken into account. The energy transfer curves are obtained, and the concvision is compared with previous result in the case of pump light to be constant.展开更多
文摘一、前言本文介绍笔者设计的一种新型数字化自控系统,它使核磁共振磁强计的系统误差和锁定重复性均优于1×10-7,跟踪速度高达30mT/s,锁定点的温漂小于2×10-7(△B)/B/℃,性能大大超过了模拟自控系统[1][2]。二、工作原理当边缘振荡器的振荡频率满足核磁共振条件时,共振信号的出现与磁场调制三角波信号fm之间的关系如图1 a 所示,共振信号在时间轴上是等距离分布的。经前置放大后,这个等距分布的信号序列触发单稳态电路,得到脉宽为T/4。
文摘A method for exact solution to forward degenerate four-wave mixing in transmission geometry for photo refractive media is presented. The effects of pump depletion and light absorption in the nonlinear dynamic media are taken into account. The energy transfer curves are obtained, and the concvision is compared with previous result in the case of pump light to be constant.