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Thermal Properties of Materials Characterized by Scanning Electron-Acoustic Microscopy 总被引:1,自引:0,他引:1 下载免费PDF全文
A modified technique of scanning electron-acoustic microscopy is employed to determine thermal diffusivity of materials. Using the dependence of the electron-acoustic signal on modulation frequency of the electron beam, the thermal diffusivity of materials is characterized based on a simplified thermoelastic theory. The thermal diffusivities of several metals characterized by the modified scanning electron-acoustic microscopy are in good agreement with the referential values of the corresponding materials, which proves that the scanning electronacoustic microscopy can be used to characterize the thermal diffusivity of materials effectively. In addition, for micro-inhomogeneous materials, such as biological tissues, the macro-effective (average) thermal diffusivities are characterized by the technique. 相似文献
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传统的电脑键盘按键声信号采集方法是采用造价较高的低噪声马达以恒定的速度敲击键盘按键,通过传声器远距离采集键盘的按键声,该方法在自然环境下受环境噪声影响大,需在低噪声环境中进行,因此很难在工业上大规模使用。该文提出了一种新型的电脑键盘按键声信号采集方法,首先采用模拟信号驱动电磁铁模拟手指敲击键盘按键,然后通过缩小检测距离和设计隔声腔有效实现对环境噪声的隔离,最终使传声器有效采集键盘按键声信号。该方法有利于同类型设备在工业上的大规模使用,并可大幅度降低设备生产成本。 相似文献
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