Search

A brief review is given on the topic of viscously-evolving accretion discs around compact objects that covers the developmentof analytical studies and our numerical model freddi allowing comparison of theory with observations.

The results of experimental and theoretical studies aimed at creating of the device for high-precision measurements of the extended optical fiber length are presented. Now the length of fibers with a length about tens kilometer is measured with an accuracy of several meters. However, in the case of some interferometric measurements it is necessary to know lengths of long fibers with an accuracy of millimeters. The equipment by means of which it can be done is rather expensive. In this work the description of the simple device developed by us which allows measuring a fiber length with extreme accuracy to millimeters is submitted, the results of measurements and the assessment of their accuracy are shown. The principle of work consists of the registration of a phase shift when you change settings of parameters of the laser radiation extended through an optical fiber. The effectiveness of measuring technique was checked on segments of optical fiber of a predetermined length with accuracy about 1 mm.