Wed, 09 Jul 2008 15:53:29 BST CiteULike: norris Houston http://www.citeulike.org/user/norris/author/Houston CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/norris/article/1074603 <i>Applied Physics Letters, Vol. 88, No. 4. (2006)</i><br /><br />Simple models are presented for estimating viscous damping of fluid (gas or liquid) loaded mechanical resonators. The models apply to beams in flexural modes of vibration, and to thin beams and plates in longitudinal modes of vibration. Predictions of the associated quality factor are compared with measured values for several macroscale and microscale resonators. The scaling of viscous loss with oscillator size is discussed. The minimum detectable mass is estimated for several oscillator designs and it is shown that, for comparably sized devices, longitudinal resonators have the lowest threshold of detection. This minimum detectable mass is proportional to scale to the power 1.75 for all resonator architectures limited by viscous damping, and it is shown that the viscous loss is 220 times larger in water than in air. ©2006 American Institute of Physics Effect of viscous loss on mechanical resonators designed for mass detection Joseph Vignola John Judge Jacek Jarzynski Maxim Zalalutdinov Brian Houston Jeffrey Baldwin doi:10.1063/1.2165186 Applied Physics Letters, Vol. 88, No. 4. (2006) 2007-01-29T15:56:41-00:00 2006 Applied Physics Letters 88 4 AIP damping http://www.citeulike.org/user/norris/article/1074601 <i>Applied Physics Letters, Vol. 88, No. 14. (2006)</i><br /><br />Two-dimensional arrays of coupled nanomechanical plate-type resonators were fabricated in single crystal silicon using e-beam lithography. Collective modes were studied using a double laser setup with independent positioning of the point laser drive and interferometric motion detector. The formation of a wide acoustic band has been demonstrated. Localization due to disorder (mistune) was identified as a parameter that limits the propagation of the elastic waves. We show that all 400 resonators in our 20×20 array participate in the extended modes and estimate group velocity and density of states. Applications utilizing the resonator arrays for radio frequency signal processing are discussed. ©2006 American Institute of Physics Two-dimensional array of coupled nanomechanical resonators Maxim Zalalutdinov Jeffrey Baldwin Martin Marcus Robert Reichenbach Jeevak Parpia Brian Houston doi:10.1063/1.2190448 Applied Physics Letters, Vol. 88, No. 14. (2006) 2007-01-29T15:54:40-00:00 2006 Applied Physics Letters 88 14 AIP damping phonons quantum http://www.citeulike.org/user/norris/article/699273 <i>Applied Physics Letters, Vol. 86, No. 18. (2005)</i><br /><br />The temperature dependence (15–320  K) of the acoustic dissipation was studied for some lower vibrational modes of a suspended silicon plate 1.5  µm thick. Our oscillator was exposed to the laboratory environment prior to measurement, laser annealed while in a cryogenic vacuum, and remeasured. We find a dissipation peak at 160  K, similar to results by others, and a second dissipation peak near 30  K. Annealing reduced the dissipation at 160  K by as much as a factor of 10, and gave quality factors as high as 1.4×106 at 470  kHz and our lowest temperature. Our data support the idea that the 160  K peak is related to adsorbates, and show this mechanism is important at room temperature. Post-anneal room-temperature dissipation appears to be limited by thermoelastic loss for certain modes. Effects of annealing and temperature on acoustic dissipation in a micromechanical silicon oscillator Hans Haucke Xiao Liu JF Vignola BH Houston MH Marcus JW Baldwin doi:10.1063/1.1921354 Applied Physics Letters, Vol. 86, No. 18. (2005) 2006-06-17T15:00:50-00:00 2005 Applied Physics Letters 86 18 AIP damping plates thermoelasticity http://www.citeulike.org/user/norris/article/699191 <i>Journal of Applied Physics, Vol. 97, No. 2. (2005)</i><br /><br />The room-temperature quality factors of silicon micromechanical oscillators have been investigated by scanning laser vibrometry. One of the flexural modes has very little attachment loss to its environment, which enables us to study internal loss mechanisms. After several consecutive annealing steps up to 800  °C, the quality factor Q has increased from 8×104 to 6.0×105. However, the Q decays to 1.4×105 over six months in air. We conclude that near-surface lattice defects caused by reactive-ion etching and surface adsorbates are the main source of internal loss while surface adsorbates are responsible for the time dependence. We also discuss the thermoelastic limit in terms of Zener's theory and flexural modal components of thin plates with vibratory volume change, and compare it with our results. A loss mechanism study of a very high Q silicon micromechanical oscillator Xiao Liu JF Vignola HJ Simpson BR Lemon BH Houston DM Photiadis doi:10.1063/1.1819980 Journal of Applied Physics, Vol. 97, No. 2. (2005) 2006-06-17T14:41:37-00:00 2005 Journal of Applied Physics 97 2 AIP damping plates thermoelasticity