Order−Disorder Transition and Phase Separation in the MgB2 Metallic Sublattice Induced by Al Doping

2009 ◽  
Vol 5 (7) ◽  
pp. 1858-1864 ◽  
Author(s):  
S. Brutti ◽  
G. Gigli
Keyword(s):  
Phase Separation ◽  
Al Doping ◽  
Disorder Transition ◽  
Metallic Sublattice

Effects of Mg-Doping on Structure and Electric Properties of MgxZn1-xO:Al Ceramics

2010 ◽  
Vol 97-101 ◽  
pp. 475-478
Author(s):  
Hua Wang ◽  
Zhu Huang ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Ming Fang Ren
Keyword(s):  
Phase Separation ◽  
Carrier Concentration ◽  
Electrical Conduction ◽  
Doping Level ◽  
Single Phase ◽  
Raw Materials ◽  
Electric Properties ◽  
Al Doping ◽  
Mg Doping ◽  
Mg Content

MgxZn1-xO:Al ceramics with low resistivity using ZnO, MgO and Al2O3 nano-powders as raw materials were obtained by unpressurized sintering. The influence of Mg content on structure and electric properties of MgxZn1-xO:Al ceramics were studied. The results indicate that there is a single phase of wurtzite structure of ZnO in MgxZn1-xO:Al ceramics at x ≤ 0.3, and when the value of x was 0.3, phase separation was observed. The grains become smaller and more homogeneous with increasing Mg content to above 0.3. The resistivity of MgxZn1-xO:Al ceramics obviously increases with increasing Mg concentration due to the decrease of the carrier concentration and the mobility deriving from the decrease of Al-doping efficiency. The electrical conduction of MgxZn1-xO:Al ceramics can be markedly improved by increasing the Al-doping level and the lowest resistivity of 8.3×10-4Ω•cm can be obtained when Mg/(Mg+Zn)=0.2 and Al/(Mg+Zn+Al)=0.03.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

Phase separation in sol gel-derived ceramic films of silica-zirconia, alumina-zirconia, and titania-zirconia system

1994 ◽  
Vol 52 ◽  
pp. 646-647
Author(s):  
J. Tong ◽  
L. Eyring
Keyword(s):  
Fracture Toughness ◽  
Phase Separation ◽  
Sol Gel ◽  
Great Influence ◽  
High Strength ◽  
Chemical Durability ◽  
Separation Method ◽  
Toughening Mechanism ◽  
Ceramic Films ◽  
Zirconia Toughened Alumina

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.

Phase separation in fluid additive hard sphere mixtures?

1998 ◽  
Vol 95 (2) ◽  
pp. 131-135 ◽  
Author(s):  
DOUGLAS HENDERSON DEZSO BODA KWONG-YU CHAN
Keyword(s):  
Phase Separation ◽  
Hard Sphere

The plant response to heat requires phase separation

Nature ◽  
2020 ◽  
Vol 585 (7824) ◽  
pp. 191-192 ◽  
Author(s):  
Simon Alberti
Keyword(s):  
Phase Separation ◽  
Plant Response

Smectic a1 ↔ a2 transition of n_c-60.8 : a two-dimensional phase separation of the molecular endgroups

1989 ◽  
Vol 50 (3) ◽  
pp. 375-385 ◽  
Author(s):  
H. Fadel ◽  
D. Guillon ◽  
A. Skoulios ◽  
F. Barbarin ◽  
M. Dugay
Keyword(s):  
Phase Separation ◽  
Two Dimensional
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