Dwell-time distributions in quantum mechanics

Some fundamental and formal aspects of the quantum dwell time are reviewed, examples for free motion and scattering off a potential barrier are provided, as well as extensions of the concept. We also examine the connection between the dwell time of a quantum particle in a region of space and flux-flux correlations at the boundaries, as well as operational approaches and approximations to measure the flux-flux correlation function and thus the second moment of the dwell time, which is shown to be characteristically quantum, and larger than the corresponding classical moment even for freely moving particles.Comment: To appear in "Time in Quantum Mechanics, Vol. 2", Springer 2009, ed. by J. G. Muga, A. Ruschhaupt and A. del Camp

Recent progress in the application of SMA thin ribbons for fire/heat sensing

More than ten years we produce thin ribbons of shape memory TiNi-based alloys by melt spinning and planar flow casting techniques and last seven years manufacture a number of thermosensitive devices, including thermal relays, thermal regulators for temperature control, fire/heat sensitive detectors. For these years annual production of the devices grew from several thousand up to about two million pieces. Using thin ribbon makes it possible to provide the following sensors features : miniature dimensions, high speed of response, wide range of switching temperatures, low switching temperature error, the guaranteed number of operation cycles more than 104. Designs and some characteristics of developed and produced devices are presented

Bragg reflectors for cylindrical waves

A transfer matrix method is developed to calculate the electromagnetic field in a dielectric structure with circular cylindrical symmetry. The equations for the reflection and transmission coefficients of cylindrical waves from a single cylindrical boundary between two dielectrics and from a cylindrical multilayered structure are obtained. For a single dielectric interface, enhanced reflection at small interface radii and the analogue of the Brewster effect are predicted and investigated. The design of an optimized cylindrical Bragg reflector (CBR) for cylindrical waves is proposed and its optical properties are studied. It is found that the thicknesses of the layers in the CBR must be different, to provide the adjustment of the phase of the waves, that are reflected from the interfaces at different radii

Thermosensitive devices based on rapidly quenched shape memory alloys

Paper describes a number of thermosensitive devices, including thermal relays, heat sensitive detectors, based on shape memory effect. Thermosensitive part of the devices is made of a small piece of TiNi-based thin ribbon produced by melt spinning technique. Owing to this developed devices are of miniature size, high speed response, narrow temperature hysteresis, low cost. Industrial production of several types of thermosensors was organized. Designs and some characteristics of the devices are presented