变压器油中溶解气体拉曼光谱检测及其光谱线型模型分析

拉曼光谱气体检测技术能利用单一波长的激光对气体样品进行无接触、无损耗检测,适用于油浸式变压器油中溶解气体检测。结合拉曼光谱检测机理,分析了拉曼光谱谱线特征,建立了由洛仑兹函数与高斯函数卷积表示的拉曼光谱Voigt线型模型,其表现出较好的拉曼谱峰线型轮廓基本特征。以谱峰高、中心位置、半峰全宽等为代表的拉曼谱峰线型轮廓基本特征是寻峰的主要目标,其根本目的在获取样本定性及定量检测分析依据。故针对拉曼光谱实验数据设计了基于比较法的自动寻峰模型以实现检测目标。对引入到Voigt线型模型中的寻峰模型进行的模拟实验结果表明,模拟中谱峰高、中心位置等数据均与模型输出数据相吻合。依托实验室构建的变压器油中溶解气体拉曼光谱检测平台,分析检测实验数据表明,Voigt线型模型中半峰全宽参数实际取值区间为(8.7,11.5)(cm-1),模型与其存在偏差。修正该参数取值为10.257 cm-1,并对比研究表明：修正后的Voigt线型模型及寻峰模型具有更好的适应性及实用性。结合实验平台的拉曼光谱气体检测数据的寻峰结果,有效地完成了七种变压器故障特征气体的检测及分析。针对甲烷气体,获得单位气体含量、拉曼特征峰强度与面积三者之间的线性关系,为变压器油中溶解气体拉曼光谱检测定量分析奠定基础。     

Development of series SQUID array with on-chip filter for TES detector

A cold preamplifier based on superconducting quantum interference devices(SQUIDs)is currently the preferred readout technology for the low-noise transition edge sensor(TES).In this work,we have designed and fabricated a series SQUID array(SSA)amplifier for the TES detector readout circuit.In this SSA amplifier,each SQUID cell is composed of a first-order gradiometer formed using two equally large square washers,and an on-chip low pass filter(LPF)as a radiofrequency(RF)choke has been developed to reduce the Josephson oscillation interference between individual SQUID cells.In addition,a highly symmetric layout has been designed carefully to provide a fully consistent embedded electromagnetic environment and achieve coherent flux operation.The measured results show smooth V-Φcharacteristics and a swing voltage that increases linearly with increasing SQUID cell number N.A white flux noise level as low as 0.28μφ;/Hz;is achieved at 0.1 K,corresponding to a low current noise level of 7 pA/Hz;.We analyze the measured noise contribution at mK-scale temperatures and find that the dominant noise derives from a combination of the SSA intrinsic noise and the equivalent current noise of the room temperature electronics.     

Line positions,intensities, and Einstein A coefficients for 3-0 band of 12C16O: A spectroscopy learning method

Based on the model- and data-driven strategy, a spectroscopy learning method that can extract the novel and hidden information from the line list databases has been applied to the R branch emission spectra of 3-0 band of the ground electronic state of ¹²C¹⁶O. The labeled line lists such as line intensities and Einstein A coefficients quoted in HITRAN2020 are collected to enhance the dataset. The quantified spectroscopy-learned spectroscopic constants is beneficial for improving the extrapolative accuracy beyond the measurements. Explicit comparisons are made for line positions, line intensities, Einstein A coefficients, which demonstrate that the model- and data-driven spectroscopy learning approach is a promising and an easy-to-implement strategy.     

地磁环境下基于SQUID三轴磁强计的矢量稳场

超导量子干涉器件(Superconducting Quantum Interference Device, 简称 SQUID) 是一种高灵敏度的矢量磁探测器. 本文采用低温超导SQUID 作为传感器, 搭建了一套三轴矢量磁场稳定装置. 该系统由两个三轴 SQUID磁强计模块、 比例积分微分(PID) 控制器和反馈线圈组组成. 在该系统的矢量稳场下, 磁场波动峰峰值在有效带宽内可以降低四个数量级, 可达pT 量级, 稳场效果显著. 此技术可以满足大部分需要稳定磁场, 如高灵敏度磁传感器的标定等应用场合.