194 research outputs found
Biphoton ququarts as either pure or mixed states, features and reconstruction from coincidence measurements
Features of biphoton polarization-frequency ququarts are considered. Their
wave functions are defined as functions of both polarization and frequency
variables of photons with the symmetry obligatory for two-boson states taken
into account. In experiments, biphoton ququarts can display different features
in dependence on whether experiments involve purely polarization or
(alternatively) polarization-frequency measurements. If in experiments one uses
only polarization measurements, the originally pure states of ququarts can be
seen as mixed biphoton polarization states. Features of such states are
described and discussed in details. Schemes of coincidence measurements for
reconstruction of the ququart's parameters are suggested and described
The Development of New Casting Alloys Intended for Operation Under Extreme Conditions and Some Techniques of Making Castings From Them
The article studies new heat-resistant and wear resistant materials for operation under extreme conditions, especially in the power industry. The methods that improve the quality of a metal in metal castings through the influence of alloying elements on its structure and properties have been considered. These methods are very effective for reducing the tendency of a metal to form a coarse–grained structure. The paper describes optimal techniques for melting special alloys in induction and electric furnaces. A set of rules for the selection of a melting temperature before pouring a metal into the casting forms depending on the dimensions, wall thickness, geometry of castings have been determined. The behavior of new alloys under the conditions of high temperatures, aggressive environments has been studied.It has been established that heat–resistant Cr–Al steels exhibit high heat resistance and wear resistance properties; they 6–8 times surpass Cr–Ni steels in oxidation resistance. The proposed Cr–Mn cast iron processed in an integrated manner with REM (rare earth metals) and Ti is superior to a basic cast iron in conditions of a heavy wear. Numerous industrial trials confirm the usefulness of recommended new casting materials for use under extreme conditions
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