Role of Elastic Interphase Deformations in the Formation of Crystal Structure of β-Nb Particles Precipitating in a Zr–2.5% Nb Alloy

X-ray diffraction analysis has been used to study the structure of the α-Zr matrix phase and the precipitation of β-Nb particles upon the annealing of a Zr–2.5% Nb deformed alloy. It has been found that the process of the precipitation of the strengthening β-Nb particles in the alloy is accompanied by the appearance of fields of elastic interphase deformations in the matrix α phase of the alloy due to the difference in the specific atomic volumes of the crystal structures of the matrix and precipitated phases. It has been shown experimentally that, as a result of the presence of interphase deformations in the alloy, the bcc crystal structure of the precipitating β-Nb particles undergoes monoclinic distortions.     

A Digital Scintillation Detector for the MEDIANA Medical Diagnostic Station

A digital position-sensitive X-ray imaging scintillation detector has been designed for the MEDIANA medical diagnostic station of the Kurchatov Synchrotron Radiation Center (the Kurchatov Institute). A single-crystal CsI(Tl) scintillator 8 mm thick is used as a screen with approximately 100% detection efficiency for X rays with energies as high as 100 keV. A CCD matrix of dimensions 1024 × 1024 pixels is the photodetector. The spatial resolution is five line pairs per mm in a field of vision of 35 × 35 mm for 100-keV X rays.     

The Principles of Calculus of Behavior Scenarios of Complex Systems in the ECS

Theoretical results of the development of the principles of scenario calculus are presented, which are obtained in the framework of the design of an emergency control system (ECS). Relying on the suggested system concept of the formation of a scenario system, consideration is given to the principles of the construction of operations in scenario spaces, which account for specific features of the scenario analysis and the process of the decision-making in the ECS. Principal problems of the development of scenario calculus on the basis of a system approach are treated, the classification of operations on scenarios is given, and a number of operations on elements of the basic metacollection are formalized.     

On the stability of the angular stabilization system of the rotating rod under longitudinal acceleration

The influence of the longitudinal acceleration on the stability of a discrete-continuous model of a single-channel angular stabilization system for the elastic rotating rod with the retarded argument is studied. Methods for the construction of asymptotic stability regions and analysis of impulse response functions of the hybrid dynamic system under consideration are developed. The equations of motion of this system are analyzed based on numerical methods and methods of asymptotic integration. Critical values of the longitudinal acceleration are found.     

Mott and Efros–Shklovskii Variable-Range Hopping Conduction in Films Formed by Silicon Nanoparticles Doped with Phosphorus and Boron

Semiconductors - The electrical characteristics of thin films formed from Si nanoparticles (nc-Si) with various degrees of doping are studied. To eliminate the influence of ionic conduction, the...     

Efficient approximation algorithms for the routing open shop problem

We consider the routing open shop problem being a generalization of two classical discrete optimization problems: the open shop scheduling problem and the metric traveling salesman problem. The jobs are located at nodes of some transportation network, and the machines travel on the network to execute the jobs in the open shop environment. The machines are initially located at the same node (depot) and must return to the depot after completing all the jobs. It is required to find a non-preemptive schedule with the minimum makespan. The problem is NP-hard even on the two-node network with two machines. We present new polynomial-time approximation algorithms with worst-case performance guarantees.     

The service of periglase-chromite refractories in the bottom of a converter with combined blowing

Conclusions Without the use of guniting and effective buildup of a crust the life of a converter bottom lining under the conditions of Nizhnii Tagil Metallurgical Combine does not exceed 400–450 heats.Unstable life (150–300 heats) of the upper layer of the bottom lining is an indication of irrational heating up of the converter before service.As follows from the experimental heats, to increase the life of the area near the tuyeres and the joint of the converter bottom and wall linings it is necessary to use BPGK-72-12 periclase-carbon blocks.Translated from Ogneupory, No. 4, pp. 48–50, April, 1990.