光谱频移的炸药熔铸温度网络监测系统研究

为了准确、稳定、全面地获得炸药熔铸过程各个位置的温度变化情况,设计了基于布喇格光栅光谱频移的温度实时监测系统。通过光纤组网系统对炸药熔铸过程炸药指定位置的多个点同时进行实时温度监测,根据光栅的布喇格波长与光栅温度之间存在的线性关系,建立光栅布喇格波长线性频移与光栅温度的函数,获取炸药不同位置的准确温度。四个通道通过耦合器共用同一个宽带光源,每一根光纤上的5个光栅的布喇格波长相互分开。实验所用的光栅为自己设计封装好的光栅,用保偏熔接机将光栅与光纤熔接上,经解调仪获取温度数据。将获取的温度数据经Origin处理绘制时间―温度曲线。结果显示,布喇格光栅测得的温度能很好的满足实验要求。     

First-Principles Study of Intrinsic Point Defects of Monolayer GeS

The properties of six kinds of intrinsic point defects in monolayer GeS are systematically investigated using the“transfer to real state”model,based on density functional theory.We find that Ge vacancy is the dominant intrinsic acceptor defect,due to its shallow acceptor transition energy level and lowest formation energy,which is primarily responsible for the intrinsic p-type conductivity of monolayer GeS,and effectively explains the native p-type conductivity of GeS observed in experiment.The shallow acceptor transition level derives from the local structural distortion induced by Coulomb repulsion between the charged vacancy center and its surrounding anions.Furthermore,with respect to growth conditions,Ge vacancies will be compensated by fewer n-type intrinsic defects under Ge-poor growth conditions.Our results have established the physical origin of the intrinsic p-type conductivity in monolayer GeS,as well as expanding the understanding of defect properties in lowdimensional semiconductor materials.     

基于光纤布拉格光栅的浇注炸药固化温度监测

首次采用光纤Bragg光栅实时测量浇注炸药在固化成型过程中固化剂与粘结剂的反应放热量。为了实时、准确的测量出浇注炸药在固化过程中的温度值,设计了基于光纤布拉格光栅的组网式温度监测系统。鉴于炸药成分的危险性、以及浇注炸药固化过程时间长、对条件要求恒温的特殊性,直接的实时监测一直未找到合适的测量方法。近年来,光纤布拉格光栅由于其优越的特点,在通信和传感领域得到广泛应用。利用光纤光栅与温度之间的线性关系,将采集的光栅反射波长值换算为温度实时显示。通过波分复用技术在两根光纤上写入7个光栅点同时测量,多点分布式测量可以将炸药内部温度的分布趋势显示出来。封装的光栅传感器采用90°弯曲设计,不仅改进了传感器与跳线的连接,同时有利于装入烘箱内。Origin软件将txt数据绘制成曲线图形式,将固化过程温度的变化直观明了的显示出来。结果表明,该方法操作简单,精确度高,满足炸药固化过程中对温度的测试需求。