Specific Features of Photoconductivity of Tl1-xIn1-xSnxSe2 Monocrystals at Low Temperatures

The photoconductivity spectra in the temperature range T≈36-200 K and the spectra of thermostimulated currents in the temperature range T≈70-300 K of Tl1-xIn1-xSnxSe2 single crystals obtained by directional crystallization of Bridgman-Stockbarger have been studied. The induced photoconductivity and long-term photoconductivity relaxation processes have been found. To interpret the found results, a model of two-center recombination has been suggested. It is illustrated that the role of the r-centers of slow recombination are formed by Tl vacancies. On the basis of the studies of the spectra of thermally stimulated currents, the thermal energy of electrons activation with t-levels of adhesion has been determined.

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Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

Physics and Chemistry of Materials Treatment ◽

10.30791/0015-3214-2020-3-66-73 ◽

2020 ◽

pp. 66-73

Author(s):

A.M. Magerramov ◽

◽

N.I. Kurbanova ◽

M.N. Bayramov ◽

N.A. Alimirzoyeva ◽

...

Keyword(s):

Transition Temperature ◽

Molecular Mobility ◽

Fe3o4 Nanoparticles ◽

Low Temperatures ◽

Frost Resistance ◽

Relaxation Processes ◽

Ethylene Propylene ◽

Temperature Range ◽

Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

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Long-Term Survival of Campylobacter jejuni at Low Temperatures Is Dependent on Polynucleotide Phosphorylase Activity

Applied and Environmental Microbiology ◽

10.1128/aem.01366-09 ◽

2009 ◽

Vol 75 (23) ◽

pp. 7310-7318 ◽

Cited By ~ 31

Author(s):

Nabila Haddad ◽

Christopher M. Burns ◽

Jean Michel Bolla ◽

Hervé Prévost ◽

Michel Fédérighi ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Low Temperatures ◽

Survival Rates ◽

Polynucleotide Phosphorylase ◽

Wild Type ◽

Term Survival ◽

Poultry Products ◽

Bacterial Gastroenteritis

ABSTRACT Campylobacter jejuni is a leading cause of bacterial gastroenteritis worldwide. Infection generally occurs after ingestion of contaminated poultry products, usually conserved at low temperatures. The mechanisms promoting survival of C. jejuni in the cold remain poorly understood despite several investigations. The present study provides insight into the survival mechanism by establishing the involvement of polynucleotide phosphorylase (PNPase), a 3′-5′ exoribonuclease with multiple biological functions in cold survival. The role of PNPase was demonstrated genetically using strains with altered pnp genes (which encode PNPase) created in C. jejuni F38011 and C. jejuni 81-76 backgrounds. Survival assays carried out at low temperatures (4 and 10°C) revealed a difference of 3 log CFU/ml between the wild-type and the pnp deletion (Δpnp) strains. This did not result from a general requirement for PNPase because survival rates of the strains were similar at higher growth temperatures (37 or 42°C). trans-Complementation with plasmid pNH04 carrying the pnp gene under the control of its natural promoter restored the cold survival phenotype to the pnp deletion strains (at 4 and 10°C) but not to the same level as the wild type. In this study we demonstrate the role of PNPase in low-temperature survival of C. jejuni and therefore attribute a novel biological function to PNPase directly related to human health.

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The ferromagnetic domain structure of haematite

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1968.0067 ◽

1968 ◽

Vol 303 (1475) ◽

pp. 525-529 ◽

Cited By ~ 10

Keyword(s):

Low Temperature ◽

Single Crystals ◽

Domain Structure ◽

Low Temperatures ◽

Remanent Magnetization ◽

Temperature Transition ◽

Small Temperature ◽

Temperature Range ◽

Ferromagnetic Domain ◽

Synthetic Crystals

Observations are reported of the ferromagnetic domain structure of natural and synthetic single crystals, made at temperatures close to the low temperature transition with the aid of an acetone based magnetic colloid. The domain structure of the synthetic crystals was found to change radically over a small temperature range centred around –12 °C. These changes are correlated with the measured remanent magnetization. Fairly extensive colloid patterns were found on the natural crystals at low temperatures but when the natural crystals were annealed at 1200 °C this low temperature colloid structure was no longer found.

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Role of Magnetic Subsystems to Form a Complex Magnetic Structure Mn2GeO4 Single Crystals

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.233-234.129 ◽

2015 ◽

Vol 233-234 ◽

pp. 129-132 ◽

Cited By ~ 1

Author(s):

Nikita V. Volkov ◽

N.V. Mikhashenok ◽

K.A. Sablina ◽

A.I. Pankrats ◽

V.I. Tugarinov ◽

...

Keyword(s):

Single Crystals ◽

Magnetic Structure ◽

Low Temperatures ◽

Spin Reorientation ◽

Manganese Ions ◽

Resonance Properties ◽

Spiral Magnetic Structure

Present paper reports of resonance properties of Mn2GeO4 single crystals. The data confirm the formation of a complex spiral magnetic structure at low temperatures. It is shown that the spin reorientation may be associated with the competition anisotropic contributions of the various subsystems of the manganese ions.

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THERMAL EXPANSION OF SINGLE CRYSTALS OF ZINC AT LOW TEMPERATURES

Canadian Journal of Physics ◽

10.1139/p65-126 ◽

1965 ◽

Vol 43 (7) ◽

pp. 1328-1333 ◽

Cited By ~ 16

Author(s):

D. A. Channing ◽

S. Weintroub

Keyword(s):

Experimental Data ◽

Thermal Expansion ◽

Single Crystals ◽

Low Temperatures ◽

Linear Thermal Expansion ◽

Optical Interference ◽

Temperature Range ◽

Thermal Expansion Coefficients ◽

Expansion Coefficients ◽

Good Agreement

The linear thermal expansion coefficients αψ of two single crystals of Zn of orientations ψ = 10.8° and 63.9 ° with the hexad axis were measured over the temperature range of about 20–270 °K using an absolute Fizeau optical interference technique. The two principal coefficients, [Formula: see text] and [Formula: see text], corresponding to ψ = 0° and 90 ° respectively, were calculated from the Voigt relation, and their values are compared with previously reported experimental data. Above 60 °K there is good agreement with previous work, and below 60 °K the results confirm, in general, the data obtained by McCammon and White. The Grüneisen parameter γ is essentially constant at about 2.1 in the range 100–270 °K, but below 100 °K γ rises appreciably with decreasing temperature and reaches the value of about 3.5 at 20 °K.

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The remanent magnetization of haematite single crystals

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1968.0066 ◽

1968 ◽

Vol 303 (1475) ◽

pp. 511-524 ◽

Cited By ~ 13

Keyword(s):

Transition Temperature ◽

Single Crystals ◽

Low Temperatures ◽

Remanent Magnetization ◽

Sharp Reduction ◽

Narrow Temperature Range ◽

Temperature Range ◽

Fast Neutron Irradiation ◽

Theoretical Predictions ◽

Synthetic Crystals

The variation of the remanent magnetization with temperature of several synthetic and natural single crystals of haematite has been measured in the temperature range 60 to –90 °C. Particular attention was given to the measurement of the remanence at temperatures close to the transition temperature. The remanent magnetization of the synthetic crystals showed a sharp reduction over a narrow temperature range; the natural crystals showed a much smaller reduction over a wider temperature range. All the specimens were found to be magnetic at low temperatures which is not in accord with theoretical predictions. The effect of annealing at high temperatures on the behaviour of the remanent magnetization was investigated. The results of measurements of the remanent magnetization of specimens which had been subjected to fast neutron irradiation are also reported.

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