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1

Calculation of the Unstable Mixing Region in Zn_{1-x}Cd_xO Ternary Alloys

100%

Shtepliuk I.

Acta Physica Polonica A

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2013

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vol. 124

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issue 5

865-868

EN

The Zn_{1-x}Cd_xO ternary alloys with a narrow band gap, which are useful for light emitters in the visible wavelengths, are studied with respect to the unsteady region in mixing. This unstable region in mixing is calculated from the free energy of mixing using the strictly regular solution model. The interaction parameter used in this calculation is obtained by means of the valence-force-field model. An influence of the strain energy induced by substrate on the region of the spinodal decomposition for the Zn_{1-x}Cd_xO system is studied and discussed.

2

Semi-Empirical Modelling of Glass Forming Ranges for Y-Co-Si System

100%

Śniadecki Z., Narojczyk J., Idzikowski B.

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vol. 126

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issue 1

62-63

EN

Glass forming abilities of a ternary Y-Co-Si system were determined on the basis of combined semi-empirical Miedema's and geometric models. The enthalpy of amorphous and solid solution phases formation, along with the mismatch entropy and GFA parameter, were analysed to indicate compositions with the highest ability for the amorphization. The large atomic radii difference between constituents, especially Y and Si, is the deciding factor of GFA. Compositions ranged between Y_{33}Si_{67} and Y_{45}Si_{55} are the best glass formers.

3

The Refurbished Z Facility: Capabilities and Recent Experiments

100%

Matzen M., Atherton B., Cuneo M., Donovan G., Hall C., Herrmann M., Kiefer M., Leeper R., Leifeste G., Long F., Mckee G., Mehlhorn T., Porter J., Schneider L., Struve K., Stygar W., Weinbrecht E.

Acta Physica Polonica A

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2009

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vol. 115

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issue 6

956-958

EN

The Z Refurbishment Project was completed in September 2007. Prior to the shutdown of the Z facility in July 2006 to install the new hardware, it provided currents of ≤ 20 MA to produce energetic, intense X-ray sources ( ≈1.6 MJ, > 200 TW) for performing high energy density science experiments and to produce high magnetic fields and pressures for performing dynamic material property experiments. The refurbishment project doubled the stored energy within the existing tank structure and replaced older components with modern, conventional technology and systems that were designed to drive both short-pulse Z-pinch implosions and long-pulse dynamic material property experiments. The project goals were to increase the delivered current for additional performance capability, improve overall precision and pulse shape flexibility for better reproducibility and data quality, and provide the capacity to perform more shots. Experiments over the past year have been devoted to bringing the facility up to full operating capabilities and implementing a refurbished suite of diagnostics. In addition, we have enhanced our X-ray backlighting diagnostics through the addition of a two-frame capability to the Z-Beamlet system and the addition of a high power laser (Z-Petawatt). In this paper, we will summarize the changes made to the Z facility, highlight the new capabilities, and discuss the results of some of the early experiments.

4

Phase and Structural Behaviour of the PrAlO_{3}-SmAlO_{3} System

100%

Basyuk T., Vasylechko L., Fadeev S., Berezovets V., Trots D., Niewa R.

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issue 1

98-103

EN

High resolution in situ X-ray powder diffraction applying synchrotron radiation and differential thermal analysis/scanning calorimetry methods have been used to examine the pseudo-binary system PrAlO_3-SmAlO_3. Two kinds of solid solutions with rhombohedral and orthorhombic structure exist at room temperature. At elevated temperatures, a continuous phase transition Pm3m ↔ R3c and a first-order transformation R3c ↔ Pbmn occur in the two respective phases. A sequence of low-temperature phase transformations R3c ↔ Imma ↔ C2/m has been detected in Pr_{1-x}Sm_xAlO_3 samples with x < 0.35. Based on in situ powder diffraction and differential thermal analysis/scanning calorimetry data, the phase diagram of the pseudo-binary system PrAlO_3-SmAlO_3 has been constructed.

5

Properties of the Semi Spin Glass Ground State of Garnets

100%

Koper A., Lehmann-Szweykowska A., Thomas M., Wojciechowski R.

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EN

A strong magnetic ordering response to valence-uncompensated doping observed experimentally in yttrium iron garnet, indicates the importance of a thorough analysis of the problem. Within the framework of the classical two-sublattice Heisenberg model the position on the ground state phase diagram, corresponding to the experimentally found values of the superexchange parameters of yttrium iron garnet, turns out to lie close to the semi spin glass region. Thus, in this paper, the magnetic structure factor, the spectrum of magnetic excitations, the density of states and a magnetic contribution to the specific heat, are calculated and discussed.

6

Mechanism and Kinetics of Precipitation and Dissolution of GP Zone and Metastable Phase in Al-3wt% Cu Alloy

100%

Khamel B., Sahnoune F., Fatmi M., Brihi N.

Acta Physica Polonica A

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2017

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vol. 131

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issue 1

133-135

EN

Thermal analysis techniques remain important tools amongst the large variety of methods used for analysis of the precipitation and dissolution of the Guinier-Preston zone and metastable phase θ' in Al-3wt% Cu. In the present study, the kinetics of precipitation and dissolution of the Guinier-Preston zone and metastable phase θ' in Al-3wt% Cu was investigated using differential scanning calorimetry carried out between room temperature and 430°C at heating rates of 20, 25, and 30°C min¯¹. The activation energies evaluated through isothermal differential scanning calorimetry treatment using the Johnson-Mehl-Avrami theory were 25, 100, and 80 kJ mol¯¹ for the Guinier-Preston zone precipitation, formation of θ'/θ and dissolution of θ', respectively. The Avrami constant n obtained by the Ligero method was about 1.5 for the formation of θ'/θ indicating that bulk nucleation is dominant in θ'/θ formation controlled by diffusion from a constant number of nuclei.

Refine search results

Calculation of the Unstable Mixing Region in Zn_{1-x}Cd_xO Ternary Alloys

Semi-Empirical Modelling of Glass Forming Ranges for Y-Co-Si System

The Refurbished Z Facility: Capabilities and Recent Experiments

Phase and Structural Behaviour of the PrAlO_{3}-SmAlO_{3} System

Properties of the Semi Spin Glass Ground State of Garnets

Mechanism and Kinetics of Precipitation and Dissolution of GP Zone and Metastable Phase in Al-3wt% Cu Alloy