Diamond microcrystals have been synthesized using ultrasonic cavitation of a suspension of hexagonal graphite in various organic liquid media, at an average bulk temperature of the liquid up to 120°C ...and at atmospheric pressure. The yield of diamond is up to 10% by mass. The diamonds were characterized by scanning electron microscopy, X-ray diffraction and laser Raman spectroscopy. Analysis of the crystallite size distribution showed that the diamonds were nearly mono-dispersed, having a size 6 or 9μm ± 0.5μm, with cubic, crystalline morphology.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We theoretically study the transfer of energy from a fiber mode to surface plasmon polaritons at the silver/air interface in the taper region of a silver-coated fiber tip. We describe conditions, ...under which a transfer efficiency from the fiber mode to the surface plasmon polariton of up to 46% can be achieved. Propagation of the surface plasmon polaritons towards the tip of the tapered structure leads to a strong subwavelength localization of the excitation enabled by a substantial increase of the surface plasmon polariton wave vector approaching the tip. The resulting strong field enhancement and confinement has a tremendous potential for applications in ultrahigh resolution tip-enhanced near-field optical microscopy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
ABSTRACT
Eruptions of young stellar objects (YSOs) are rare events, therefore a new outburst is always noteworthy. We present two new high-amplitude variable YSOs, J183421.85−055951.0 (#1) and ...J183421.39−055937.7 (#2), in the RAFGL 7009S star-forming region. We find them in the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Plane Survey data base, and supplement these data with archived infrared and millimetre photometric and spectral images and data from the Spitzer Infrared Array Camera, the K-band Multi-Object Spectrograph, and the Atacama Large Millimeter/submillimeter Array data bases. The outburst in #1 occurred in the period 2007–2011, during which the brightness increased by ∼2.7 mag in the K band and by ∼2.5 mag in the 3.6 μm band. The colour indices indicate a YSO in Class I/II evolutionary stage. After outburst, the K-band spectrum shows the CO band, Brγ, Mg i in absorption and H2 in emission – characteristics associated with a FU Orionis (FUors)-type eruptive variable. Object #1 is associated with an outflow detected in the near-infrared and millimetre ranges, mainly in the H2, SiO, HCO+, and HCN lines. Object #2 only shows high-amplitude variability in the K band (ΔK = 2.0 mag) while its colour indices before outburst indicate a YSO at an early evolutionary stage. There is no obvious outflow activity associated with this object. We classify #1 as a FUor-type eruptive variable based on the obtained data. The limited information on #2 makes it difficult to draw definite conclusions about the nature of its variability.
This study aims to determine the main physical parameters (N(H
2
) hydrogen column density and T
d
dust temperature) of the Interstellar medium, and their distribution in the extended star-forming ...region, which includes IRAS 05156+3643, 05162+3639, 05168+3634, 05177+3636, and 05184+3635 sources. We also provide a comparative analysis of the properties of the Interstellar medium and young stellar objects. Analysis of the results revealed that Interstellar medium forms relativity dense condensations around IRAS sources, which are interconnected by a filament structure. In general, in sub-regions T
d
varies from 11 to 24 K, and N(H
2
) - from 1.0 to
4.0
×
10
23
cm
−
2
. The masses of the ISM vary from
1.7
×
10
4
to
2.1
×
10
5
M
⊙
. All BGPSv2 objects identified in this star-forming region are located at the N(H
2
) maximum. The direction of the outflows, which were found in two sub-regions, IRAS 05168+3634 and 05184+3635, correlates well with the isodenses’ direction. The sub-regions with the highest N(H
2
) and Interstellar medium mass have the largest percentage of young stellar objects with Class I evolutionary stage. The wide spread of the evolutionary ages of stars in all sub-regions (from 10
5
to
10
7
years) suggests that the process of star formation in the considered region is sequential. In those sub-regions where the mass of the initial, parent molecular cloud is larger, this process is likely to proceed more actively. On the
Gaia
EDR3 database, it can be assumed that all sub-regions are embedded in the single molecular cloud and belong to the same star-forming region, which is located at a distance of ∼1.9 kpc.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The generation of a magnetic field in a strange quark star owing to differential rotation of the superfluid and superconducting quark core relative to the normal electron-nuclear crust of the star is ...examined. The maximum possible magnetic field on the surface is estimated for various models of strange dwarfs. Depending on the configuration parameters, i.e., the mass M and radius R of the star, a range of 103–105 G is found. These values of the magnetic field may be an additional condition for identification of strange dwarfs among the extensive class of observed white dwarfs.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The mechanism for magnetic field generation in hybrid neutron stars (containing “npe,” hadron, “2SC” and “CFL” quark phases) is discussed. It is assumed that the rotational vortices in “npe” and ...“CFL” phases with a quantum of circulation h/2m also continue in the “2SC” phase. Since the superconducting components in the “npe” and “2SC” phases are charged, entrainment currents develop around the vortices and generate a magnetic field. The average magnetic field in the quark phase is on the order of 5·10
15
G and exceeds the field in the “npe” phase by 2-3 orders of magnitude. The magnetic field penetrates into the “CFL” phase by means of magnetic vortices with a flux 2Φ
0
and it can partially destroy the proton superconductivity in the “npe” phase. On the star’s surface, the magnetic field reaches 5·10
14
G, a level comparable to the magnetic field of magnetars. Magnetars may, therefore, contain quark matter.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Some mechanisms for gravitational radiation from neutron and quark stars are examined. The amplitudes of gravitational waves from a deformed star as it rotates and from an oscillating star during ...irregular changes in its rotation dynamics are calculated. The feasibility of detecting gravitational waves with existing detectors is discussed. Depending on the character of the signals, when gravitational waves are detected it can be established whether strange quark matter is present in compact gravitational wave sources.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The article is devoted to the contribution of Soviet domestic science to the study of the peasant class in the second half of the XVIII century. in the Russian Empire. The position of the peasantry ...in state policy is analyzed, and the scientific schools of the Soviet period specializing in the study of the system of serfdom are considered. The question is raised about the scientific achievements of Soviet historical science in the complex of using the existing approaches, scientific schools, and the system of knowledge about the development of the peasantry in the Russian Empire in the second half of the XVIII century. The study of social and economic processes of development of the peasant class during the evolution of feudal relations was the most popular topic of scientific research in Soviet historiography. The problems related to the condition of dependent peasants during the period of serfdom in tsarist Russia deserve careful study and continue to arouse interest in the works of Russian researchers.
The generation of a magnetic field and its distribution inside a rotating bare strange quark star are discussed. It is shown that the difference between the angular velocities of the superfluid and ...superconducting quark core Ω
s
and of the normal electron plasma Ω
n
increases because of spin-down of the star and this leads to the generation of a magnetic field. The magnetic field distribution in a star is found for a stationary value of ∆Ω=Ω
s
- Ω
n
= const . The magnetic field in the superconducting quark core and in the normal electron shell is continuous along the star’s axis of rotation and has the same value
B
q
=
B
n
, while it is a dipole field outside the star. In all parts of the star this field is determined entirely by the total magnetic moment M of the star. It is also shown that the star’s magnetic moment M is proportional to ΔW, and for some models of compact stars it can vary from 10
31
-10
34
G·cm
3
.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Generation of a magnetic field and its distribution are considered within a rotating strange quark star with a crust. It is shown how, over time, a differential rotation is established between the ...superfluid and superconducting quark core and normal electron plasma, which leads to the generation of magnetic field. The magnetic field at the surface of a strange star may attain values of 1011–1015 G, depending on the star model. It is suggested that magnetars may be manifestations of strange stars, the cores of which rotate much faster than the observable part, i.e., the crust.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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