Absolute structure-factor measurements of an Al–Pd–Mn quasicrystal

Abstract

A number of X-ray re¯ections from an icosahedral quasicrystal Al±Pd±Mn have been measured with great accuracy on an absolute basis by making use of Braggcase diffraction. Since the specimen had high crystal quality, the dynamical theory was used for analyzing the results and to extract structure factors from measured integrated intensities. Good agreement was found between theory and experiment for strong re¯ections. Anomalous transmission was found to be strong in the`good' regions of the quasicrystalline specimen and it was measured on an absolute basis, but the small residual strains present in the specimen prevented an accurate comparison between theory and experiment. A detailed discussion is presented on the parameters that mostly affect anomalous transmission in relationship to the adopted structural model.

Investigation The Effect of Particle Size and Annealing on the Performance of Nano/Micro Sized ZnO-Based Varistors

“…Where the sample of 20nm ZnO achieved the highest nonlinearity coefficient at 49.89 as illustrates in table 3. The decrease in porosity related to the increasing in the nonlinear coefficient as has been proved in another study [15]. Table 3.…”

“…Such dopants play an important role on improving the microstructure of ZnO by modifying the grains size and grains growth during the sintering process which can in turn lead to improve the electrical properties. Recent research focuses on studying the factors that play an important role to make varistors more stable with low leakage current such as sintering temperature, the sintering period, and the type of sintering [13,14,15]. Annealing process is a heat treatment used to modify the microstructure to improve the crystallization and get rid of defects in material which involving slowly cooling the sample after heating at a specific temperature for a while to achieve a near equilibrium condition of characteristics [24].…”

“…Annealing process is a heat treatment used to modify the microstructure to improve the crystallization and get rid of defects in material which involving slowly cooling the sample after heating at a specific temperature for a while to achieve a near equilibrium condition of characteristics [24]. Many researchers studied the effect of post annealing in different environments on improving the microstructure and homogeneity of grains and increasing their size, which inevitably affects the performance of varistors [1,2,14,15]. Besides, electrical and microstructure properties of varistors can be changed by modifying the initial particle size which enhance the grain size uniformity and the microstructure density [17,18].…”

Novel Schiff base scaffolds derived from 4‐aminoantipyrine and 2‐hydroxy‐3‐methoxy‐5‐(phenyldiazenyl)benzaldehyde: Synthesis, antibacterial, antioxidant and anti‐inflammatory

“…The chemistry of antipyrine and its derivatives has sparked a lot of attention in recent years. These compounds have been shown to have analgesic and anti‐inflammatory 6 characteristics, as well as, antibacterial action 7‐12 . In addition, it is used in hair dyes, spectrophotometric metal ion measurements and as potential ligands for the construction of poly nuclear compounds as bioinorganic system models, and the discovery of new catalytic precursors 13‐17 .…”

“…These compounds have been shown to have analgesic and anti-inflammatory 6 characteristics, as well as, antibacterial action. [7][8][9][10][11][12] In addition, it is used in hair dyes, spectrophotometric metal ion measurements and as potential ligands for the construction of poly nuclear compounds as bioinorganic system models, and the discovery of new catalytic precursors. [13][14][15][16][17] Antiparasitic antipyrine Schiff base derivatives have been reported to work as anticancer agents in metal complexes with platinum(II) and cobalt(II) ions.…”