US Aide in China Taken Ill in a Case Echoing Cuba Acoustic Attacks

  1. US Aide in China Taken Ill in a Case Echoing Cuba Acoustic Attacks  Wall Street Journal
  2. US warns staff in China: Beware of unusual sounds  BBC News
  3. US warns its citizens in China after official suffers brain injury reminiscent of possible ‘sonic attack’  Business Insider
  4. US issues alert after employee in China reports ‘abnormal’ sound sensations  CNN
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Source: Google News

New metasurface model shows potential to control acoustic wave reflection

Typically, when a soundwave strikes a surface, it reflects back at the same fundamental frequency with a different amplitude. A new model shows that when a sound wave hits a nonlinear elastic metasurface, the incident fundamental frequency does not bounce back. Instead, the metasurface converts that energy into the wave’s second harmonic resonance. Developing this metasurface could help architects reduce noise from performance halls to cityscapes.
Source: Science Daily