间断性屈膝缺血预适应对小鼠缺氧耐力的影响

目的:观察和比较两种后肢缺血法产生的缺血预适应对小鼠耐受缺氧能力的影响。方法:昆明小鼠96只,分成对照组、间断屈膝固定组(KF)或束缚大腿组(TT)进行缺血预适应。每天预适应1次,7 d后各组小鼠再分为3组分别进行常压耐缺氧实验、亚硝酸钠中毒实验和断头后心、脑耐缺血实验。结果:两种后肢缺血法小鼠常压耐缺氧时间均显著延长(P<0.01),断头后张口呼吸时间显著高于对照组(P<0.05)。但对亚硝酸钠中毒生存时间和心脏跳动时间没有明显影响。结论:肢体缺血预适应能显著增强小鼠缺氧耐力。

Monitoring Method for the Electrical Properties of Piezoelectric Transducer

The monitoring of cutting force in a vibration cutting process has a great significance in the popularization of ultrasonic vibration cutting technology. A new monitoring method of which the cutting force of ultrasonic elliptic vibration cutting is monitored using the electrical properties of transducer was proposed by studying on the relationship of cutting force, transducer electric impedance and load. A measurement system was designed for the electrical properties of transducer. The feasibility of cutting force monitoring method based on the electrical properties of piezoelectric transducer was proved by the cutting experiments.