【正文】
加系統(tǒng)吸收的選擇性時,則需減少阻尼,亦即提升 Q值 。考慮系統(tǒng)外力對系統(tǒng)所作之功率為 222222222 ??????????????????????????????dtdxmdtdxxdtxddtdxmdtdxxdtdxdtxdmdtdxFFvP oo ????? ? ???????????? 222221221dtdEdtdxmkxxmdtd??222222222 ??????????????????????????????dtdxmdtdxxdtxddtdxmdtdxxdtdxdtxdmdtdxFFvP oo ????第一項(xiàng)為振子之力學(xué)能變化,當(dāng)振動進(jìn)入穩(wěn)定態(tài)之後,其週期平均值應(yīng)為零, 0?TdtdE)(s i n22 2222 ????? ??? tmcxmP ?所以在振動進(jìn)入穩(wěn)定態(tài)之後週期平均消耗功率為 ? ?? ?2222222224 ????????????oomFmcP利用數(shù)學(xué)結(jié)果 )(s in22 2222 ????? ??? tmcxmP ?=1/2 這結(jié)果表示,系統(tǒng)對能量的吸收與頻率有關(guān)。我們稱此頻率為共振頻率(resonance frequency),而此時系統(tǒng)處於共振(resonance)狀態(tài)。 22 20 ??? ??? o? ?? ? ? ?2222222 42/?????? ?????ooo mFckFmFc ooo ??2/?(一)當(dāng) ?=0時, 。s gravity. Each of these otolith ans contains a small sensory area known as a macula. Each macula contains several thousand vestibular hair cells. The cilia are embedded in a gelatinous matrix called the otolithic membrane. This membrane contains small piles of calcium carbonate crystals (CaCO3), called otoliths, a word which literally means ear stones. 阻尼諧振子 (Damped Oscillators) 考慮一系統(tǒng)的阻力 (retarding force)為 R=bv,恢復(fù)力 (restoring force)為 kx,則由牛頓運(yùn)動定律可得 ? ???????? 22dtxdmdtdxbkxmabvkxF 此運(yùn)動方程與所熟悉的簡諧運(yùn)動微分方程差異於多出一次微分項(xiàng)。其週期為 mg dIT ???22??A uniform rod of mass M and