| 摘要 |
To the anode of an X-ray tube a basic direct current voltage is applied, approaching the threshold voltage required for the excitation of the analyzed element, and superimposed on this voltage is a sinusoidal alternating voltage. In the positive portions of the sinusoidal voltage the combined voltage exceeds the threshold voltage, whereas in the negative portions it lies below the same. The contents of the analyzed element is registered by a detector whose electronic evaluating device is selectively sensitive to the third or higher harmonics.
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