湿度对骨内压电信号的影响

对不同相对湿度下的骨压电电压和压电电荷信号进行测量研究,来考察湿度对骨压电信号的影响.采用三点弯曲干骨试样,以梯形脉冲载荷的方式进行加载,分别应用超高输入阻抗的生物信号放大器和电荷放大器测量了三种不同相对湿度下的骨压电电压和压电电荷信号波形.结果表明,骨压电电压峰值随湿度的增加而下降很快,当湿度从30%增至60%时,电压降幅达到了80%左右;基于测试原理的不同,骨压电电荷也随湿度的增加而下降,其降幅较小.由此可以推断,骨在体内湿润的状态下,受力变形时压电电压幅值可能趋于零.电荷的产生和瞬时泄放有可能是骨在体内的动态载荷作用下的压电效应的表现形式.

On the Influence of Relative Humidity on Piezoelectric Signals

The piezoelectric effect of bone is related to relative humidity levels. Under trapezoidal pulse loading, piezoelectric signals of dry bone samples three-point bending were measured at different relative humidity levels. Piezo-voltages were obtained by using an ultra high input impedance bioamplifier. For the sake of comparing, piezo-charges of bone were also measured. Results show that piezo-voltage of bone quickly decreases with humidity increasing. Piezo-voltage decreases around 80% along with the relative humidity increases from 30% to 60%. The measured piezo-charge also decreases at lower rate along with humidity increasing due to different test principle. It is concluded that piezo-voltage induced by deformation of bone may be performed in a pulse style under dynamic loads.