Lamb modes exhibit a resonant behavior at frequencies where the group velocity vanishes while the phase velocity remains finite. This type of zero group velocity (ZGV) point exists in most isotropic materials at the minimum frequency-thickness product of the first order symmetric (S1) Lamb mode. Laser sources couple efficiently into this resonance and a sharp peak is observed with source and re...

If I say the word “wave” in no particular context, the image which most probably springs to your mind is one of a roughly periodic undulation on the surface of a pond or, perhaps, the sea. But the concept of a wave in classical physics is actually much more general, and in particular the periodicity is not really an essential aspect. At least in classical (i.e. pre-relativistic as well as pre-q...

An improved version of the " optical bar " intracavity readout scheme for gravitational-wave antennae is considered. We propose to call this scheme " optical lever " because it can provide significant gain in the signal displacement of the local mirror similar to the gain which can be obtained using ordinary mechanical lever with unequal arms. In this scheme displacement of the local mirror can...

Passing underground trains induce vibrations transmitted to the ground surface and the nearby structures. Ordinarily, these vibrations do not result in structural damage but can harm nonstructural elements and disturb the occupants. These effects are more pronounced when evaluating buildings like hospitals, laboratories, museums, etc., and their assessment is an important design need. To respon...

NMR technique of modulated gradient spin echo makes possible to measure the power spectra of displacement and velocity autocorrelation functions of the air-fluidized granular beds. The obtained frequency distribution of displacement and velocity spectra at different degrees of fluidization leads to an empiric formula that well-fits to the experimental data and gives negative long-range tail of ...

Motivated by a recently invented scheme of displacement-noise-free gravitational-wave detection, we demonstrate the existence of gravitational-wave detection schemes insusceptible to both displacement and timing (laser) noises and are thus realizable by shot-noise-limited laser interferometry. This is possible due to two reasons: first, gravitational waves and displacement disturbances contribu...

Two-dimensional ocean wave spectra are measured from ENVISAT ASAR wave mode cross spectra on a global scale. The measurement is performed using a parametric retrieval scheme, which makes use of prior information taken from numerical wave models. The Partition Rescale and Shift algorithm (PARSA) is based on a partitioning technique, which splits an a prior wave spectrum into its wave system comp...

Two-dimensional ocean wave spectra are measured from ENVISAT ASAR wave mode cross spectra on a global scale. The measurement is performed using a parametric retrieval scheme, which makes use of prior information taken from numerical wave models. The Partition Rescale and Shift algorithm (PARSA) is based on a partitioning technique, which splits an a prior wave spectrum into its wave system comp...

Displacement reaction of 2,3-dichloroquinoxaline with secondary amines in boiling ethanol afforded it`s mono aminoquinoxaline derivatives. Further reaction of the latter compounds with sodium azide in warm dimethylsulfoxide achieved a group of 4-amino tetrazolo[1,5-a]quinoxaline derivatives. 1HNMR spectra of these compounds are discussed.