椎弓根钉植入针道上骨组织光谱特性研究

运用光谱技术研究了椎骨组织不同位置的特征识别因子.光谱采集系统由双光纤手钻一体式探头(光纤芯径200 μm,中心距离0.5 mm)、卤素光源(波长360~2 000 nm)、光纤光谱仪(检测波长为200~1 100 nm)和计算机组成,可以同时获得生物组织的漫反射光谱和约化散射系数.以猪椎骨为实验对象,测量椎弓根螺钉植入针道上不同骨组织的漫反射光谱和约化散射系数,并对光谱进行特定波长的峰值、面积、斜率分析,获得特性识别因子.研究发现,椎弓根钉植入针道上不同骨组织的光谱表现出不同的变化特性.其中峰值的变化比约化散射系数的变化高1.88倍,面积的变化比约化散射系数的变化高2.05倍.在495~505 nm处,骨密质和骨疏质的光谱斜率都为正值;在520~535 nm处,骨密质光谱的斜率为正值,而骨疏质光谱的斜率为负值.结果表明,通过光谱特性分析获得的峰值、面积和斜率因子能够有效地区分针道上骨密质与骨疏质的差异.

Experimental Investigation on the Gain Characteristics of Laser Gyro

The gain characteristics of laser gyro were investigated by measuring the relative strength of the laser gyro′s side spectrum.It was obtained experimentally that the gain of the laser gyro increases with the increasing of the current,the gyro gain presents the saturated gain phenomena with the increasing of the total pressure and the gain reaches a maximum value when the total pressure is about equal to 4P0.By comparing the time-varying gain curves of aluminum cathode and B cathode gyroscope in the gyro′s start-up phase and corrying out error analysis of experimental data,the experimental results show that the gain stability and anti-environmental interference capability of B cathode gyro are better than that of aluminum cathode gyro.The gain of active medium and the beat′s frequency shift induced by the Langmuir flow effects both are related to the population density difference of the producing laser′s upper and lower level.The experimental results show that the zero drift′s stability of the laser gyro can be evaluated by the gyro gain′s stability.