Effect of La3+ on microwave dielectric properties of (Pb0.45Ca0.55) (Fe0.5Nb0.5)O-3 ceramics

In this work, microwave dielectric properties of A-site substitution by La3+ in (Pb0.45Ca0.55) (Fe0.5Nb0.5) 03 system were investigated. Microwave dielectric properties of A-site charge unbalance substitution of [(Pb0.45Ca0.55)(1-x) La-x] (Fe0.5Nb0.5)O-3(+) (P45CLFN) were improved because the solid solution of small amount of surplus La3+ with (Pb, Ca)(2+) could eliminate oxygen vacancies, and the formation of secondary phase (pyrochlore) was also caused by surplus La3+. The decreasing of dielectric constant with the increase of La3+ content is due to the formation of pyrochlore. The grain size is changed slightly and Q(f) values (7000 similar to 7300 GHz) are almost unchanged at x = 0.02 similar to 0.10, but the temperature coefficient of resonant frequency (TCF) are increased and changed from negative to positive. TCF is zero at x 0.075 with Q(f) = 7267 GHz and K = 89. TCF of all specimens are within +/- 5 x 10(-6)degrees C-1.

基于光栅传感器的位移测量仪的研制

本文介绍一种基于光栅传感器的位移测量仪。它通过硬件电路对2个光栅传感器输出的信号分别进行20细分,然后对细分后的信号分别进行辨向和计数,再使用一个微处理器对辨向信号和计数信号进行处理,得到X-Y工作台在坐标X和坐标Y方向的位移值,最后根据误差修正算法对位移测量值进行修正,得到该仪器的测量分辨率为1μm且测量精度达±2μm（1σ）。此外,所研制的测量仪具有可靠、易于扩展和调试方便的特点。