The interaction of point defects with dislocations in high-purity silver above room temperature

1990 ◽  
Vol 2 (2) ◽  
pp. 273-279 ◽  
Author(s):  
P J Grigsby ◽  
H M Simpson ◽  
J W Hemsky
Keyword(s):  
Point Defects ◽  
High Purity ◽  
Room Temperature

Preparation of High-Purity Ultrafine α-Al2O3 by Solid-State Reaction at Room Temperature

2008 ◽  
Vol 368-372 ◽  
pp. 683-685
Author(s):  
Cheng Wei Hao ◽  
Bo Lin Wu ◽  
Ji Yan Li
Keyword(s):  
Solid State ◽  
High Purity ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Raw Materials ◽  
Phase Particle ◽  
Phase Transformation Temperature ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Α Al2o3

Ammonium aluminium carbonate hydroxide (AACH), with a small quantity of γ-AlOOH, was synthesized through solid-state reaction at room temperature using AlCl3·6H2O and NH4HCO3 as raw materials and polyethylene glycol (PEG-10000) as the dispersant. After calcined at 1100°C for 1.5h, α-Al2O3 powders with primary particle sizes of 20~30nm were obtained. The crystal phase, particle size and morphology of the high-purity ultrafine α-Al2O3 were characterized. The results showed that a small quantity of γ-AlOOH in the AACH decomposed and formed crystal seeds. The presence of crystal seeds reduced the nucleation activation energy and therefore reduced the phase transformation temperature.

Anelastic deformation of high purity aluminum at room temperature

1976 ◽  
Vol 10 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Nahum Nir ◽  
Edward W. Hart ◽  
Che-Yu Li
Keyword(s):  
High Purity ◽  
Room Temperature ◽  
High Purity Aluminum ◽  
Anelastic Deformation

Correlation between Room Temperature Photoluminescence and Resistivity in Semiinsulating Silicon Carbide

2006 ◽  
Vol 527-529 ◽  
pp. 717-720 ◽  
Author(s):  
Sashi Kumar Chanda ◽  
Yaroslav Koshka ◽  
Murugesu Yoganathan
Keyword(s):  
Low Temperature ◽  
Point Defects ◽  
Room Temperature ◽  
Vanadium Content ◽  
Mapping Technique ◽  
Native Defect ◽  
Room Temperature Photoluminescence ◽  
Native Point Defects ◽  
Pl Mapping ◽  
Resistivity Variation

A room temperature PL mapping technique was applied to establish the origin of resistivity variation in PVT-grown 6H SiC substrates. A direct correlation between the native defect-related PL and resistivity was found in undoped (V-free) samples. In vanadium-doped samples with low vanadium content, the resistivity showed a good correlation with the total PL signal consisting of contributions from both vanadium and native point defects. Well-known UD1 and UD3 levels were revealed by low-temperature PL spectroscopy. Some correlation was observed between these low-temperature PL signatures and the resistivity distribution.

Preparing high purity λ-Ti3O5 and Li/λ-Ti3O5 as a high performance electromagnetic wave absorber

2021 ◽  
Author(s):  
xiankai fu ◽  
Wanqi Chen ◽  
Xiaowen Hao ◽  
Zhimin Zhang ◽  
Ruolan Tang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
High Purity ◽  
High Performance ◽  
Room Temperature

This paper reports a new candidate material λ-Ti3O5 for microwave absorption. λ-Ti3O5 has been proposed to be metastable and has emerged at room temperature only in the form of nanocrystals....

Zinc carbonate recovery from brass melting slag

2021 ◽  
Vol 98 ◽  
pp. 14-18
Author(s):  
Thao Nguyen Thi ◽  
◽  
Nam Pham Ky ◽  
Ngoc Tran Vu Diem
Keyword(s):  
Sulfuric Acid ◽  
High Purity ◽  
Room Temperature ◽  
Ph Value ◽  
Zinc Carbonate ◽  
Leaching Solution ◽  
Optimized Conditions ◽  
Melting Slag

Brass melting slag (20.38 wt.% Zn) was leached in sulfuric acid with concentration of (50 + 80) g/l H2SO4, leaching temperature of (30 + 60) °C for (30 + 120) min. The optimized conditions for 94.16% Zn extraction from brass melting slag were found as 70 g/l H2SO4, room temperature and 90 min. The leaching solution was purified by removal of Fe through Fe(OH)3 precipitation when adding ZnO to adjust pH value of 5. The solution was continuously cemented by Zn metal at 60 °C for 60 min to obtain Cu metal with high purity of 99 wt.% Cu. The purified solution with 37.64 g/l Zn was modified by Na2C03 to have pH value of about 6 and precipitation of ZnC03 (94.14 %).

Positron annihilation in fatigued copper

1982 ◽  
Vol 60 (2) ◽  
pp. 201-204 ◽  
Author(s):  
S. Kupca ◽  
D. P. Kerr ◽  
B. G. Hogg ◽  
Z. S. Basinski
Keyword(s):  
Single Crystals ◽  
Point Defects ◽  
High Purity ◽  
Low Temperatures ◽  
Annealing Process ◽  
Simple Diffusion ◽  
Diffusion Limited ◽  
Annealing Study ◽  
Positron Lifetimes ◽  
Trapping Process

Positron lifetimes have been measured in an isochronal annealing study of dynamically fatigued, high purity Cu single crystals. Decomposition of the lifetime spectra into two components results in a description of the annealing process in terms of the lifetime and fraction of trapped positrons. Positron lifetimes were also determined at a series of low temperatures (10–300 K) at different stages of annealing. The lifetime of positrons trapped at point defects is found to vary with temperature indicating that a description of the trapping process according to a simple diffusion limited model is not applicable.

Impurity and Stoichiometry Control in Atomic Layer Epitaxy

1992 ◽  
Vol 262 ◽  
Author(s):  
H. Yokoyama ◽  
K. Ikuta ◽  
N. Inoue
Keyword(s):  
Point Defects ◽  
Resonant Tunneling ◽  
Room Temperature ◽  
Defect Density ◽  
Atomic Layer ◽  
Negative Resistance ◽  
Atomic Layer Epitaxy ◽  
Tunneling Diode ◽  
Order Of Magnitude ◽  
Stoichiometry Control

ABSTRACTWe investigate the intrinsic point defects in epilayers grown by atomic layer epitaxy (ALE). Ga vacancies and antisite As atoms in the epilayers are detected by photoluminescence spectroscopy. This shows that the ALE epilayer was grown under As-rich conditions. We propose increasing the TMG flux to reduce the number of point defects. With this method, the number of point defects in ALE epilayers can be decreased to less than that in conventionally grown epilayers. Moreover, it is'found that these point defects are formed by the incomplete Ga coverage, not by the steric hindrance as previously suggested. The carbon concentration is decreased by one order of magnitude by using nitrogen instead of hydrogen as the carrier gas. As an application of this low defect density, we fabricated a GaAs/AlAs resonant tunneling diode and observed the negative resistance at room temperature.

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