99 research outputs found
Improved production procedure for manufacturing chromium bronze bars
A thermal deformation treatment (TDT) method is developed and implemented during production of industrial batches of chromium bronze bars, according to which aging is performed after intermediate billet drawing to a prefinishing diameter, then finishing drawing of an aged billet follows to a final diameter with a drawing factor of 1.10-1.25. Batches of bars treated by this method correspond entirely to all standard document specifications with respect to hardness and longitudinal curvature, and bars have the required marketable condition with smooth, defect-free, shiny surface typical for cold-drawn products. © 2013 Springer Science+Business Media New York
Instructions for laboratory training in General Microbiology & Immunology for students of medical faculty
МИКРОБИОЛОГИЯАЛЛЕРГОЛОГИЯ И ИММУНОЛОГИЯЛАБОРАТОРНЫЕ РАБОТЫИНОСТРАННЫЕ СТУДЕНТЫПРАКТИЧЕСКИЕ НАВЫКИПРАКТИЧЕСКИЕ ЗАНЯТИЯИНСТРУКЦИИИММУНОЛОГИЯВ издании содержатся план, программа практических занятий и основные практические навыки по общей микробиологии и иммунологии
Ginzburg-Landau Expansion in a Toy Model of Superconductor with Pseudogap
We propose a toy model of electronic spectrum of two-dimensional system with
``hot-patches'' on the Fermi surface, which leads to essential renormalization
of spectral density (pseudogap). Within this model we derive Ginzburg-Landau
expansion for both s-wave and d-wave Cooper pairing and analyze the influence
of pseudogap formation on the basic properties of superconductors.Comment: 14 pages, 14 figures, RevTeX 3.0, Postscript figures attached, some
changes in the explanation of the model, published in JETP 115, No.2, (1999
Optical Conductivity in a Simple Model of Pseudogap State in Two-Dimensional System
We present calculation of optical conductivity in a simple model of
electronic spectrum of two-dimensional system with "hot patches" on the Fermi
surface, leading to non Fermi-liquid renormalization of the spectral density
(pseudogap) on these patches. It is shown that this model qualitatively
reproduces basic anomalies of optical experiments in the pseudogap state of
copper oxides.Comment: 12 pages, 6 figures, RevTeX 3.0, Postscript figures attache
Magnetooptical sum rules close to the Mott transition
We derive new sum rules for the real and imaginary parts of the
frequency-dependent Hall constant and Hall conductivity. As an example, we
discuss their relevance to the doped Mott insulator that we describe within the
dynamical mean-field theory of strongly correlated electron systems.Comment: 4 pages, 4 ps figures; accepted for publication in PR
Color Effects Associated with the 1999 Microlensing Brightness Peaks in Gravitationally Lensed Quasar Q2237+0305
Photometry of the Q2237+0305gravitational lens in VRI spectral bands with the
1.5-m telescope of the high-altitude Maidanak observatory in 1995-2000 is
presented. Monitoring of Q2237+0305 in July-October 2000, made at nearly daily
basis, did not reveal rapid (night-to-night and intranight) variations of
brightness of the components during this time period. Rather slow changes of
magnitudes of the components were observed, such as 0.08 mag fading of B and C
components and 0.05 mag brightening of D in R band during July 23 - October 7,
2000. By good luck three nights in 1999 were almost at the time of the strong
brightness peak of image C, and approximately in the middle of the ascending
slope of the image A brightness peak. The C component was the most blue one in
the system in 1998 and 1999, having changed its (V-I) color from 0.56 mag to
0.12 mag since August 1997, while its brightness increased almost 1.2 mag
during this time period. The A component behaved similarly between August 1998
and August 2000, having become 0.47 mag brighter in R, and at the same time,
0.15 mag bluer. A correlation between the color variations and variations of
magnitudes of the components is demonstrated to be significant and reaches
0.75, with a regression line slope of 0.33. A color (V-I) vrs color (V-R) plot
shows the components settled in a cluster, stretched along a line with a slope
of 1.31. Both slopes are noticeably smaller than those expected if a standard
galactic interstellar reddening law were responsible for the differences
between the colors of images and their variations over time. We attribute the
brightness and color changes to microlensing of the quasar's structure, which
we conclude is more compact at shorter wavelengths, as predicted by most quasar
models featuring an energizing central source.Comment: 14 pages, 7 figures, LaTeX, submitted to A&
Improving the durability of the dies and product quality in the production of nichrome strips
Several complicated technological problems had to be solved to develop an alternative technology for the production of nichrome strips, the new technology involving the rolling of cast ingots and drawing of the hot-rolled semifinished products. In the traditional technology, sheet is hot- and cold-rolled and then cut lengthwise to form the strips. One particularly important advance over the existing technology is the improvement made to the geometry of the drawing channel in the hard-alloy dies. This modification significantly reduces die wear, practically eliminates breakage of the strip during drawing, and substantially improves the quality of the strip's surface. © 2013 Springer Science+Business Media New York
IMPROVING THE DURABILITY OF THE DIES AND PRODUCT QUALITY IN THE PRODUCTION OF NICHROME STRIPS
Serious technological problems are encountered in the production of nichrome semifinished products of non-circular cross section (strips). In particular, nonuniform flow of metal in the width direction during flattening of the circular semifinished product in the rolls of the rolling mill causes the strip to assume a barrel shape [1]. The tool does not control the convexity of the small sides of the strip, so that it can vary in relation to the a number of process variables: the wear of the rolls; the size of the reduction being made; the character of the friction, etc. Thus, it is technically difficult to roll strips within the tolerance and keep the deviations in cross-sectional area along the strip to a minimum. Keeping the cross-sectional area constant is important for the reliable operation of nichrome heaters, since the metal overheats, is oxidized, becomes saturated with gases, and eventually loses the necessary service properties when current passes through parts of the heater with a smaller cross section, Thus, to ensure the long-term operation of such heaters, the strips which serve as the semifinished products must have stable physico-mechanical characteristics over their length. Such stability is assured by having the transverse dimensions of the strip be constant. This prerequisite is particularly important from the standpoint of maintaining a stable temperature regime in metallurgical resistance furnaces with nichrome heaters. In the technology that has traditionally been used, the nichrome semifinished products are made from sheet or wide stri
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