English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A demand for non-contact and nondestructive internal defect detection is increasing. Using a photoacoustic effect, an internal defect could be detected by a low power semiconductor laser and an ultrasonic sensor. But the sensitivity of the ultrasonic sensor is low in detecting a photoacoustic signal. Then, an internal defect detection using a photoacoustic and self-coupling effect of semiconductor laser has been studied. To generate photoacoustic signal, a semiconductor laser with output power of 20mW is focused by a lens and is illuminated at 45 degrees on the sample. To detect photoacoustic signal by the self-coupled effect, another laser with output power of 10mW is illuminated at right angle. Sample defect can be detected by illuminating these laser lights at the same point on the sample. The self-coupling sensor can detect an internal defect with more sensitivity than the ultrasonic sensor does. An edge effect and a frequency characteristic are also observed. As a result, it was able to detect a very small defect of 0.07mm.

Nondestructive Internal Defect Detection Using Photoacoustic and Self-Coupling Effect