2,426 research outputs found
Reference Voltage Supply Source with Expanded Operating Temperature Range
The circuit of reference voltage surface with enhanced operation temperature range was developed. The operating temperature range was enlarged by a current source connected to output terminal of the regular output of LM4050 voltage regulator
Magnetization and specific heat of TbFe3(BO3)4: Experiment and crystal field calculations
We have studied the thermodynamic properties of single-crystalline
TbFe3(BO3)4. Magnetization measurements have been carried out as a function of
magnetic field (up to 50 T) and temperature up to 350K with the magnetic field
both parallel and perpendicular to the trigonal c-axis of the crystal. The
specific heat has been measured in the temperature range 2-300K with a magnetic
field up to 9 T applied parallel to the c-axis. The data indicate a structural
phase transition at 192 K and antiferromagnetic spin ordering at 40 K. A
Schottky anomaly is present in the specific heat data around 20 K, arising due
to two low-lying energy levels of the Tb3+ ions being split by f-d coupling.
Below TN magnetic fields parallel to the c-axis drive a spin-flop phase
transition, which is associated with a large magnetization jump. The highly
anisotropic character of the magnetic susceptibility is ascribed mainly to the
Ising-like behavior of the Tb3+ ions in the trigonal crystal field. We describe
our results in the framework of an unified approach which is based on
mean-field approximation and crystal-field calculations.Comment: 10 pages, 10 figures, 20 references, accepted by Phys. Rev.
Distant foreground and the Planck-derived Hubble constant
It is possible to reduce the discrepancy between the local measurement of the
cosmological parameter and the value derived from the
measurements of the Cosmic Microwave Background (CMB) by considering
contamination of the CMB by emission from some medium around distant
extragalactic sources, such as extremely cold coarse-grain dust. Though being
distant, such a medium would still be in the foreground with respect to the
CMB, and, as any other foreground, it would alter the CMB power spectrum. This
could contribute to the dispersion of CMB temperature fluctuations. By
generating a few random samples of CMB with different dispersions, we have
checked that the increased dispersion leads to a smaller estimated value of
, the rest of the cosmological model parameters remaining fixed. This
might explain the reduced value of the -derived parameter with
respect to the local measurements. The signature of the distant foreground in
the CMB traced by SNe was previously reported by the authors of this paper --
we found a correlation between the SN redshifts, , and CMB
temperature fluctuations at the SNe locations, . Here we have used
the slopes of the regression lines corresponding to
different {\it Planck} wave bands in order to estimate the possible temperature
of the distant extragalactic medium, which turns out to be very low, about
5\,K. The most likely ingredient of this medium is coarse-grain () dust,
which is known to be almost undetectable, except for the effect of dimming
remote extragalactic sources.Comment: 5 pages, 4 figures, 1 tabl
Discovery of an unusual bright eclipsing binary with the longest known period: TYC 2505-672-1 / MASTER OT J095310.04+335352.8
We report on the MASTER Global Robotic Net discovery of an eclipsing binary,
MASTER OT J095310.04+335352.8, previously known as unremarkable star TYC
2505-672-1, which displays extreme orbital parameters. The orbital period
P=69.1 yr is more than 2.5 times longer than that of epsilon-Aurigae, which is
the previous record holder. The light curve is characterized by an extremely
deep total eclipse with a depth of more than 4.5 mag, which is symmetrically
shaped and has a total duration of 3.5 yrs. The eclipse is essentially gray.
The spectra acquired with the Russian 6 m BTA telescope both at minimum and
maximum light mainly correspond to an M0-1III--type red giant, but the spectra
taken at the bottom of eclipse show small traces of a sufficiently hot source.
The observed properties of this system can be better explained as the red giant
eclipsed by a large cloud (the disk) of small particles surrounding the
invisible secondary companion.Comment: 8 figures, 9 pages, Astronomy and astrophysics in prin
Investigation of the effect of high strength strips steel modification with rare-earth metal (REM)
The present work describes the study on influence of modifying steel with rare-earth metals on metallurgical quality of ingots and finished steel. To achieve the assigned task, the laboratory melting of 08G2NMDFBT (Х100) pipe steel was carried as in open (UIP 100 – 2,4), so in vacuum induction furnace (ISV-0,01 - PI) with use of conditioning agents, which contain rare-earth metals. Next materials were used as conditioning agents: mischmetal (MM), which contain total amount of rare-earth metal (REM) up to 93 %, АlPCIr and RENTN which contain total amount of from 31 to 32,6 %
Interaction between Bacillus anthracis and Pattern-Recognizing Receptors of Innate and Adaptive Immunity
According to modern views, protection of an organism from different pathogens is achieved through functioning of the two chains of immune system - innate and acquired ones. Initially, receptors of non-specific immunity, including Toll-like receptors, identify conservative pathogen-associated molecular structures. The subsequent activation of signaling pathways leads to rapid neutralization and elimination of foreign agent. Concurrently, initiation of the adaptive immunity, and realization of pro-inflammatory reactions' cascade take place. The review summarizes literature data concerning peculiarities of innate and adaptive types of immunity in case of interaction between macro-organism and Bacillus anthracis. Protective antigen, lipoprotein, cell wall components, anthrolysine O, CpG DNA sequence and others are the potential ligands of Toll-like receptors in B. anthracis. Demonstrated are the results of experiments that bear evidence of the fact, that synthetic agonists of Toll-like receptors influence realization of B. anthracis cytotoxicity and course of infection in laboratory animals. Modificators of Toll-like receptor functions can be used as immunostimulators for designing of effective means of anti-infectious protection. Innate and adaptive components of the immunity, having their own unique mechanisms of the specific B. anthracis identification, interact with each other, strengthen and complement each other
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