All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes ont...All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes onto the black hole,allowing it to grow,and its structure and evolution has been the subject of intense study in the past decade.In a recent issue of Nature Astronomy,the Chinese Academy of Sciences South America Center展开更多
The long rib of the sounding membrane in the black cicada is an analog to the beam clamped at one end. The fundamental frequency of activation sound is between 3900-5500 Hz and is basically consistent with the possibl...The long rib of the sounding membrane in the black cicada is an analog to the beam clamped at one end. The fundamental frequency of activation sound is between 3900-5500 Hz and is basically consistent with the possible range of the main peak frequency ( MPF) of song in the black cicada. The operculum (Op), tymbal cover (TC) and joint membrane (JM)are respectively analogous to a unifor square plate clamped at one edge and free at the others, to another plate at two opposite sides and free at the other, and to a rectangular membrane clamped at four sides. The fundamental frequencies of activated vibration are basically consistent with theMPFs and main high frequency components of vibrations of the Op, TC and JM, respectively.The resonant cavity and spiracles on both sides are analogous to a current resonace circuit and to a resistance connected in parallel at the output ends, and the resonant frequency and quality factor of the circuit are in good agreement with the MPF and its tuning sharpness of son the black cicada.展开更多
文摘All massive galaxies host supermassive black holes(SMBH)at their centers,and these objects are often found to be hidden behind large amounts of gas and dust.This circum-nuclear material is what eventually accretes onto the black hole,allowing it to grow,and its structure and evolution has been the subject of intense study in the past decade.In a recent issue of Nature Astronomy,the Chinese Academy of Sciences South America Center
文摘The long rib of the sounding membrane in the black cicada is an analog to the beam clamped at one end. The fundamental frequency of activation sound is between 3900-5500 Hz and is basically consistent with the possible range of the main peak frequency ( MPF) of song in the black cicada. The operculum (Op), tymbal cover (TC) and joint membrane (JM)are respectively analogous to a unifor square plate clamped at one edge and free at the others, to another plate at two opposite sides and free at the other, and to a rectangular membrane clamped at four sides. The fundamental frequencies of activated vibration are basically consistent with theMPFs and main high frequency components of vibrations of the Op, TC and JM, respectively.The resonant cavity and spiracles on both sides are analogous to a current resonace circuit and to a resistance connected in parallel at the output ends, and the resonant frequency and quality factor of the circuit are in good agreement with the MPF and its tuning sharpness of son the black cicada.
