The amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties of amorphous progesterone, one of the representative steroid hormones, were investigated by using a Bri...

Over the years, metamaterials have shown their potential in a wide range of different disciplines, e.g. optics, electromagnetics, dynamics etc. Metamaterials are, often periodic, engineered structures made conventional materials but which exhibit properties not encountered nature. In field noise and vibration, received increasing interest since they can obtain frequency ranges high vibration at...

We present five kinds of labyrinthine or space-coiling acoustic metamaterials with tapered channels and apertures. These designs exhibit negative index behavior with modest dispersion, and also have substantially improved impedance matching compared to previously investigated labyrinthine cells. Experimentally measured effective material parameters are in good agreement with numerically compute...

We report the experimental observation of self-induced modulation instability (MI) in a Brillouin fiber laser made with a solid-core photonic crystal fiber (PCF) with strong anomalous dispersion. We identify this MI as the result of parametric amplification of optical sidebands generated by guided acoustic modes within the core of the PCF. It is further shown that MI leads to passive harmonic m...

An acoustic surface plasmon, a new type of electron wave that exists on metal surfaces, has been proven to exist by Bogdan Diaconescu and Karsten Pohl, Univ. of New Hampshire, Durham. The acoustic plasmon can be excited with any wavelength. These plasmons have been predicted on theoretical grounds, and last year, a team concluded that they did not exist. This work proves their existence. Becaus...

A linear theory of dust acoustic (DA) and dust ion-acoustic (DIA) waves in a self-gravitating collisional dusty plasma contaminated by variable-charge impurities is presented for a self-consistent closed system. The ion-drag force arising from the ion orbital motion as well as momentum transfer from all the ions and self-gravitation are taken into consideration. The physical processes, viz., du...

We report here the computation and measurement of inelastic light scattering from acoustic vibrational modes in single-walled carbon nanotubes ~SWNT’s!. The measurement was made possible by the preparation of a sample of oriented SWNT’s, partially aligned by means of a magnetic field. Long-wavelength confined longitudinal acoustic modes are described by a shell model. Their interaction with lig...

Solitons are a unique class of pulse-shaped waves that propagate in nonlinear dispersive media. In the course of propagation, they maintain spatial confinement of wave energy within the pulse shape without dispersion and exhibit remarkable nonlinear dynamics. Solitons are found throughout nature where fine balance between nonlinearity and dispersion is achieved. Dispersion alone would flatten o...

ABSTRACT In this study, the vibration and sound radiation from the double-layered strip plate with air cavity between the upper and lower plates are investigated by using the waveguide finite and boundary element method. The interaction between the structural and acoustic waves propagating along the double-layered strip plate is investigated by observing the dispersion relations of the waves. T...