The short-range order and ordering energies in gold-copper polycrystalline alloys that are rich in gold

The concentration dependence of the short-range order parameters in gold-rich polycrystalline disordered solid gold-copper solutions was investigated using the X-ray diffuse-scattering method. On the X-ray diffuse-scattering patterns of disordered alloys with 75, 83, and 90% gold, diffuse maximums that are typical of short-range order were absent in the region of the possible superstructure reflex (100), but in the region of the possible reflex (110), an intensity rise on the scattering patterns was revealed that noticeably depended on the gold concentration. The application of the method, taking the effects of static displacements on the considered coordination spheres into account, allowed the determination of short-range order parameters for nine coordination spheres. The spectra of short-range order parameters, which was calculated using the least-squares method, had the long-range sign-alternating representation that is inherent in the Cu₃Au superstructure. The absolute values of short-range order parameters were detected to decrease with an increase of the gold content in the alloys. The concentration dependence and small values of ordering energy of investigated polycrystalline alloys were revealed on the first coordination sphere using the Clapp-Moss method.     

Computer design of electrostatic systems of charge particle optics: Systems with spherical electrodes and a fine-structure grid

Problems in computer-aided design of 3D optical systems for charged particle optics are analyzed. The results of simulation of electron-optical systems of optoelectronic transducers with two cathode packs (spherical cathode-plane fine-structure grid as the accelerating electrode and plane cathode-spherical fine-structure grid) are considered. We note a low technological efficiency of such structures and unsatisfactory quality (as it regards some parameters) of the image being recorded due to spherical electrodes and a fine-structure grid in the cathode pack. Numerical analysis of the effect of adjustment of the design on the quality of the image being recorded is carried out.     

Optimization of Multilayer Photonic Structures using Artificial Neural Networks to Obtain a Target Optical Response

JETP Letters - A new deep machine learning method is proposed for the task of selecting the parameters of a multilayer photonic structure to obtain a target optical spectrum of the reflection...     

Phase transitions and ion transport in NASICON materials of composition Li1 + xZr2 ? xInx(PO4)3(x = 0–1)

NASICON materials of composition Li_{1 + x} Zr_{2 − x} In _x (PO₄)₃(x = 0–1) were synthesized. The phase constitution, particle size, and conductivity of these materials were studied as s function of synthesis temperature. High-temperature X-ray powder diffraction was used to study phase transitions in the materials synthesized. Low levels (x ≤ 0.1) partial substitution of indium for zirconium considerably increase the lithium ion conductivity and reduce the activation energy for conduction compared to the parent compound.     

Computer analysis of the source image structure in 3D electron-optic systems: I. An electrostatic system

Computer analysis of the arbitrary source image obtained in 3D electron-optic systems is performed. The systems involve electrostatic fields focusing and deflecting electron beams. Specifically, the structure of a net electron beam from an extended source at the crossover is examined. It is shown that the spread function of the source, which characterizes the imaging quality of the system most fully, may serve as a primary computational criterion.     

Computer approach to the determination of electrostatic fields and capacitive coefficients for 3D multielement sets of screens

The structural components of a computer handbook on electrostatic fields and capacitive coefficients of 3D multielement sets of screens are described. The computer approach suggested is based on boundary integral equations from the 3D theory of harmonic potentials and fast algorithms of the finite-group method that are realized on a Pentium-Pro 200 MHz 128-MB RAM PC.