星期六, 6月 14, 2008

隔音斗篷 叫噪音「繞道」而過-Acoustic Cloak

 英國廣播公司(BBC)新聞網12日報導,科學家在《新物理學期刊》(New Journal of Physics)發表了一種「聲學斗篷」(acoustic cloak)構想,據說能讓聲波不及於物體。而這種科技可用於製造隔音住宅、先進音樂廳或匿蹤戰艦。

 在2006年,美國杜克大學研究人員曾製造出一種「隱形斗篷」,以微波照射置於斗篷中的物體時,斗篷會將微波的散射與陰影區降到最低;亦即從另一邊觀測時,微波猶如穿越空無一物的空間,因此觀測者「看不到」此物體。

 而今西班牙一個研究團隊進一步提出「隔音斗篷」構想,他們認為關鍵在於研發所謂的「聲音水晶體」(sonic crystals),這種人工複合材料(亦稱『超材料』,meta-materials)可經由工程開發,以產生特定聲學效果。

[更多]

Scientists have previously demonstrated devices that cloak objects from microwaves, making them "invisible".

"The mathematics behind cloaking has been known for several years," said Professor John Pendry of Imperial College London, UK, an expert in cloaking.

"What hasn't been available for sound is the sort of materials you need to build a cloak out of."

[more]