Adsorbate aggregation and relaxation of low-frequency vibrations

Vibrations of low frequency over the precordium.

A method for taking tracings which represent actual movements of the precordium (displacement curves) or records which show waves proportional to the velocity of movement of the chest wall (velocity curves) is described. The equipment employed is readily available, and the method is easy to use. The displacement curves are nearly identical with cardiograms taken with a good optical setup, and t...

Low-frequency vibrations of DNA molecules.

A model for calculating the low-frequency modes in DNA molecules is presented. The present model is associated with the 'breathing' of a DNA molecule as well as its complementary hydrogen bonds. The calculated results show excellent agreement with the observed low-frequency wavenumber (30 cm-1). Consequently, such an internal motion as reflected in the proposed model might be the origin of the ...

Low-frequency vibrations of soft colloidal glasses.

We conduct experiments on two-dimensional packings of colloidal thermosensitive hydrogel particles whose packing fraction can be tuned above the jamming transition by varying the temperature. By measuring displacement correlations between particles, we extract the vibrational properties of a corresponding "shadow" system with the same configuration and interactions, but for which the dynamics o...

MEMS Energy Harvesting from Low-Frequency and Low-Amplitude Vibrations

Continuum elastic theory of adsorbate vibrational relaxation

An analytical theory is presented for the damping of low-frequency adsorbate vibrations via resonant coupling to the substrate phonons. The system is treated classically, with the substrate modeled as a semi-infinite elastic continuum and the adsorbate overlayer modeled as an array of point masses connected to the surface by harmonic springs. The theory provides a simple expression for the rela...