Structure of chromium-nickel steel 14KH17N2 after high-temperature tempering

The structure of steel 14Kh17N2 after quenching exhibits -phase (ferrite alloyed with chromium and nickel), which causes the formation of streaks, filaments, and other defects in the metal during rolling and hot pressure treatment. The properties of the microstructure of this steel can be judged by the state of the carbide phase segregating on phase interfaces and inside grains. A complex analysis of the changes in the state of the carbide phase M₂₃C₆ in the process of high-temperature tempering of steel 14Kh17N2 (for example, at 700°C is of practical interest. The results of this analysis make it possible to make recommendations on improvement of the properties of the steel and to refine the optimum chemical and phase compositions.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5 , pp. 36–38, May, 1995.     

A pixel 21-channel drift chamber

The design of the pixel chamber is described, and the results of investigation of its characteristics are presented. The spatial resolution averaged over a cell of the pixel chamber is 0.9 mm at a beam intensity of up to 10⁶ s^?1 and becomes equal to 1.1 mm at an intensity of 5 × 10⁶ s^?1. The chamber efficiency is ～90% at a beam intensity of 10^?1 and decreases to 75% at 5 × 10⁶ s^?1.     

SAW Microsensor Brain Implant for Prediction and Monitoring of Seizures

An implantable surface acoustic wave (SAW) microsensor has been developed for early detection and monitoring of seizures based on local temperature changes in the brain's epileptogenic zones that occur prior to and during an epileptic event. Three SAW sensors were designed and fabricated: a 172 MHz filter, a 434 MHz filter, and a 434 MHz delay line. Their temperature sensitivities were tested by measuring the phase change between the input and output waveforms as a function of temperature. We achieved a phase sensitivity of 144 phase degrees per degC and a minimum detectable temperature of 5 mK for the 434-MHz, 10.2-mus delay line. Based on the sensitivity tests, a prototype 434 MHz SAW sensor was fabricated to a size of 11times1times1.1 mm, which is commensurate with existing brain implantable probes. Because of possible damping of the surface waves by the surrounding tissue or fluid, a glass housing with dry air was built on the top of the SAW substrate. Test and reference sensors were used in the prototype system to minimize the effect of source instabilities and to amplify the temperature effect. The phase change between the output waveforms of the sensors was measured with phase detector electronics after they were converted to lower (10.7 MHz) frequencies by standard mixers. The complete prototype sensor was tested in a saline water bath and found to detect as low as 3 mK changes of temperature caused by the addition of hot water.     

Efficient mixed Timoshenko–Mindlin shell elements

The precise representation of rigid body motions in the displacement patterns of curved Timoshenko–Mindlin (TM) shell elements is considered. This consideration requires the development of the strain–displacement relationships of the TM shell theory with regard to their consistency with the rigid body motions. For this purpose a refined TM theory of multilayered anisotropic shells is elaborated. The effects of transverse shear deformation and bending‐extension coupling are included. The fundamental unknowns consist of five displacements and eight strains of the face surfaces of the shell, and eight stress resultants. On the basis of this theory the simple and efficient mixed models are developed. The elemental arrays are derived using the Hu–Washizu mixed variational principle. Numerical results are presented to demonstrate the high accuracy and effectiveness of the developed 4‐node shell elements and to compare their performance with other finite elements reported in the literature. Copyright © 2002 John Wiley & Sons, Ltd.     

Optoelectronic method of contactless reconstruction of the surface profile of complexly shaped three-dimensional objects

An optoelectronic method of contactless reconstruction of the surface profile of complexly shaped threedimensional objects with the use of structured light, phase triangulation, and a steady-state method of identification of interference patterns by means of stepwise shift is considered. Analytic estimates as well as estimates obtained experimentally (using the newly developed measurement system) of the error in measurements of surface profile with the use of the proposed method are presented.     

Non‐linear exact geometry 12‐node solid‐shell element with three translational degrees of freedom per node

This paper presents the finite rotation exact geometry (EG) 12‐node solid‐shell element with 36 displacement degrees of freedom. The term ‘EG’ reflects the fact that coefficients of the first and second fundamental forms of the reference surface and Christoffel symbols are taken exactly at each element node. The finite element formulation developed is based on the 9‐parameter shell model by employing a new concept of sampling surfaces (S‐surfaces) inside the shell body. We introduce three S‐surfaces, namely, bottom, middle and top, and choose nine displacements of these surfaces as fundamental shell unknowns. Such choice allows one to represent the finite rotation higher order EG solid‐shell element formulation in a very compact form and to derive the strain–displacement relationships, which are objective, that is, invariant under arbitrarily large rigid‐body shell motions in convected curvilinear coordinates. The tangent stiffness matrix is evaluated by using 3D analytical integration and the explicit presentation of this matrix is given. The latter is unusual for the non‐linear EG shell element formulation. Copyright © 2011 John Wiley & Sons, Ltd.     

High-temperature high-dose implantation of N+ and Al+ ions in 6H-SiC

A series of experimental and theoretical investigations has been initiated for 6H-SiC samples sequentially implanted with high doses of N⁺(65 keV) + N⁺(120 keV)+Al⁺(100 keV)+Al⁺(160 keV) ions at temperatures between 200 and 800 °C. Nitrogen and carbon distribution profiles are measured by ERD and structural defect distributions are measured by Rutherford backscattering with channeling. A comparison between the experimental data and the results of computer simulation yields a physical model to describe the relaxation processes of the implanted SiC structure, where the entire implanted volume is divided into regions of different depth, having different guiding kinetics mechanisms. Pis’ma Zh. Tekh. Fiz. 23, 6–14 (August 26, 1997)     

Amorphous silicon and germanium films for uncooled microbolometers

The possibility of using amorphous silicon and germanium films prepared by magnetron sputtering as components in uncooled microbolometers has been analyzed experimentally and results are presented. Amorphous silicon and germanium films having activation energies of 0.135 and 0.2 eV, and resistivities of 50 and 0.4 kΩ·cm, respectively, were fabricated. Pis’ma Zh. Tekh. Fiz. 23, 21–26 (July 12, 1997)     

The creation of a legal-standards basis for the economic validation of nature-preserving activities in health resorts

In patients with pulmonary tuberculosis, intestinal dysbacteriosis has clinical and bacteriological features characterized by the short-age of bifidobacteria (in 88-92%), by changes in the composition of Escherichia coli strains (in 38-42%), by the presence of Candida (in 58-62%), Proteus in half the patients, and by associated dysbacteriosis. Most (75%) patients show Stage III-IV intestinal dysbiosis formed after 3-4 months of continuous chemotherapy. There is a direct relationship between the magnitude of dysbiotic disorders and the duration of chemotherapy.     

Ether lipids and platelet-activating factor: evolution and cellular function

This review considers the relation between the evolution of ether lipids and platelet-activating factor (PAF) in living organisms for the first time. Ether lipids are shown to be the main structural lipid components in the cells of the most primitive organisms on the Earth; during evolution they were gradually substituted for lipids with ester and vinyl bonds. Synthesis of PAF has been found in some bacteria, protozoans, yeasts, plants, marine invertebrates, lower vertebrates, and mammals. The regulatory role of PAF is suggested to already appear in protozoans and later be maintained during the subsequent evolution of living organisms. During evolution, functions of PAF in the cell have been changing and enlarging, while ether lipids have been gradually losing their role as the main structural lipid component of the cells of living organisms.