Phase transitions were studied for the new synthesized ferroic (NH
2(C
2H
5)
2CuCl
4 (DEA–CuCl
4) and (NH
2(C
2H
5)
4CoCl
2Br
2 (TEA–CoCl
2Br
2) nanocrystallites (NC) incorporated into polymer ...matrices. Comparison with the bulk crystals is performed. A giant temperature shift (from 305.1°C to 360.3°C) of onset temperature for TEA–CoCl
2Br
2 nanoparticles after their incorporation into the PMMA matrix was found and is substantially larger compared to the DEA–CuCl
4. The DSC analysis shows that the temperature of phase transition is crucially dependent on the thermocycling and temperature rate. The principal role of the nano-sized effects is shown.
Second-order optical susceptibilities were established in the optically poled erbium doped tellurite glasses near the melting temperature. The non-linear optical susceptibility was formed by bicolor ...coherent optical treatment performed by two coherent laser beams originated from 50
ps Nd-YAG laser (
λ
=
1.32
μm) exciting the high pressure hydrogen laser cell emitting at 1907
nm. The non-centrosymmetric grating of the medium was created by coherent superposition of the fundamental laser illumination at 1907
nm and the doubled frequency one at 953.5
nm. The maximally all-optically poled SHG occurs for 2% doped Er
2O
3 (in weighting units) TeO
2–GeO
2–PbO glass. It was found that the photoinduced SHG demonstrates a saturation during the photo-treatment of 9–10
min using the two beams polarized at angle about 45° between them. During the coherent bicolor optical treatment it was achieved the value of second-order susceptibility up to 3.6
pm/V at 1907
nm. The optimal ratio between the fundamental beam with power density about 1.1
GW/cm
2 and writing doubled frequency seeding beam about 0.015
GW/cm
2 corresponds to the maximal of photoinduced SHG. For glasses with lower concentration of Er
2O
3, the relaxation of the second-order optical susceptibility is substantially longer and achieves SHG value that corresponds to 80% of the maximal ones. It is necessary to emphasize that efficient optically-poled grating exists only within the narrow temperature range near the glassing temperature. Possible physical mechanisms of the phenomenon observed are discussed. Generally the used glasses possess better parameters than early investigated germinate glasses.
Two methods of phase transition detection — non-linear optical based on optical poling (second harmonic generation) together with traditional, calorimetrical, Differential Scanning Calorimetry are ...compared. The investigations are performed near glass transition and melting point. As examples germanate GeO
2–PbO glasses doped by Er
+3 ions are chosen. It is demonstrated that although both methods give an evidence of the transitions the non-linear optical one is much more sensitive. A short description of the experimental set-up for the optical measurements and physical aspects of the method are given.
Higher sensitivity of the SHG compared to DSC is found for the ferroelectrics nanocrystallites embedded in polyamide matrix near the melting points.
Photoinduced optical second harmonic generation ...(PISHG) and differential scanning calorimetry (DSC) methods were used for study of tetraethyl-ammonium (TEA)–CoCl
2Br
2 ferroelectric nanocrystallites (about 50
nm) near melting point. It was shown that PISHG is more sensitive to melting temperature compared to the DSC. This is caused by sensitivity of PISHG due to contribution both of ground electron states as well as of excited ones contrary to the DSC method where principal role is played by ground states.
Magnetic properties of thin electrical sheets of AN1 and AN3 types are described. Data on anisotropy of the coercive force determined from Epstein tests and from coercivemeter measurement (in an open ...magnetic circuit) anisotropy of magnetic induction in DC and AC magnetization conditions are presented. Anisotropy of core losses and degree of Goss texturing are also reported.< >
Microstructure and some magnetic properties of the bulk amorphous (Fe61Co10Zr2.5Hf2.5W2Ti2B20)100-xYx (x = 0 or 2) alloys are studied. Addition of 2 at. % of Y to the Fe61Co10Zr2.5Hf2.5W2Ti2B20 alloy ...leads to the decrease of the Curie temperature from 520 K to 438 K. Investigated alloys are magnetically soft although the Y addition gives rise to the magnetic hardening; the coercive field increases from 71 A/m for x=0 to 87.6 A/m for x=2. Approach to the magnetic saturation is governed by point-like or linear defects in the tubeshaped samples, and by linear defects in the rod-shaped samples.
The aim of the study was to estimate the quality of milk taken from particular purchase points. Research was conducted in 2003. The producers were divided into IV groups according to the amount of ...milk they deliver; these were: I - up to 1 thousand, II - up to 5 thousand, III - up to 15 thousand, IV - above 15 thousand litres of milk. The study showed that 79.94 percent of milk was of the highest quality. Most milk was produced during the pasture period
The structure evolution and low-field magnetic properties (i.e. the magnetic susceptibility and its disaccommodation) during transformation of the Fe sub 85.4 Zr sub 6.8-x Nb sub x B sub 6.8 Cu sub 1 ...(x = 0, 1) alloys from the amorphous to the nanocrystalline state are investigated. It was stated that at early stages of crystallization, the iron content in the amorphous matrix does not change. However, the interfacial layer is poorer in iron in comparison with the amorphous matrix. The annealing of the amorphous samples below the crystallization temperature leads to the decrease of the hyperfine field due to the invar effect. Moreover, at early stages of crystallization, the samples exhibit 'magnetic hardening'. The magnetic susceptibility disaccommodation of the investigated alloys is mainly connected with relaxation processes occurring in the amorphous phase.
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