Sub-100 fs Kerr lens modelocked Cr4+:YAG laser

Sub-100 fs pulse generation from a Kerr lens modelocked Cr⁴⁺ :YAG laser has been demonstrated for the first time, yielding femtosecond pulses tunable from 1.49 to 1.56 μm with pulses as short as 90 fs obtained at 1.53 μm     

Solution of the inverse problem of measurement dynamics using the state vector of a primary measuring transducer

A method is proposed for optimal tuning of the adjustable parameters of the correction device of a measuring system with partially known characteristics of the useful signal and noise described by spectral densities and using the measured state coordinate vector.     

Analysis of the microwave loss in AlGaAs/GaAs heterostructure pin-diodes

The dependence of the microwave insertion loss on the parameters of the heterostructure pin-diode is investigated by means of numerical modeling. The mechanisms of the emergence of this loss are determined, and the most influential mechanism is identified.     

A rational approach to processing cerium-containing raw materials

A method for the online control of cerium extraction from rare-earth raw materials based on the oxidation of its trivalent ions with hydrogen peroxide, followed by the precipitation of hydroxide and additional acid treatment to remove trivalent impurities has been considered.     

Simultaneous estimation of liquid level and density based on the maximum likelihood method

This paper considers the operation algorithm of a hydrostatic level sensor in a liquid of unknown density which is based on the determination of the moment when the level crosses the pressure sensor and provides increased accuracy of density and level measurements compared to available methods. The algorithm was synthesized on the basis of the maximum likelihood method. The algorithm was analyzed and experimental data are given.     

Optimization of the cambering of the roll unit in an 800 reversing mill

The cambering of the backup rolls in a reversing 800 mill is optimized. The calculations are performed with a refined technique, in which a flexure shape is described by a trigonometric series and the metal pressure distribution over a work roll is taken into account. An initial roll profile is described by a vector. The Winkler hypothesis about proportionality between the roll interaxial distance and the interroll pressure is used. The potential energy of a roll is calculated. This technique is applied to develop new cambering of the roll unit in an 800 mill, which ensures the required high-precision accuracy of rolled products. This accuracy is supported by the results of industrial tests.     

Stress,strength, and durability analysis of gradient-structured hardmetal products

We present results of finite-element analysis of stressed state in a percussive-rotary drilling bit fitted with hardmetal inserts during its contact interaction with rock, allowing for brazing-induced stresses. The most likely fracture zones in inserts have been identified. Based on the proposed criterion for fatigue strength of structurally inhomogeneous materials, the binder composition of the inserts has been optimized for the longest service life. It is demonstrated that the formation of a gradient structure in a hardmetal, whereby the material preserves its initial mechanical properties in the main volume but has an increased ultimate tensile strength in zones where tensile stresses are involved, results in a longer service life of the hardmetal products and a noticeably diminished dependence of their cyclic strength on the scale factor. __________ Translated from Problemy Prochnosti, No. 2, pp. 15–31, March–April, 2007.