Performance of Gd-Ba-Cu-O Superconductor Bulks with Ultrafine Gd2BaCuO5 Powders Prepared by Low-Temperature Combustion Synthesis

2007 ◽  
Vol 546-549 ◽  
pp. 2111-2114
Author(s):  
X.H. Ma ◽  
Xin Tai Su ◽  
Qing Zhi Yan ◽  
Y.L. Jiao ◽  
L. Xiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Combustion Synthesis ◽  
Low Temperature Combustion ◽  
Solid State Route ◽  
Morphology And Structure ◽  
Temperature Combustion ◽  
Conventional Solid State Route ◽  
Scanning Electron

This paper describes the details on synthesizing nanocrystalline Gd2BaCuO5 (Gd211) using low-temperature combustion synthesis(LCS). The morphology and structure of the powders are characterized by field emission scanning electron microscopy (FESEM) and XRD. The size of obtained powders by this method calcined at 800 C is about 100nm, which is much smaller than the powders synthesizing by conventional solid state route. Besides, the Gd211 powders synthesizing by LCS have a low calcination temperature with a high-purity. The microstructure of melt-textured samples is also observed by FESEM, the result shows that the size of Gd211 particles trapped in GdBa2Cu3O7 (Gd123) matrix could be refined by using ultrafine Gd211 powder as a precursor. The refined Gd211 particles with a good distribution resulted in the improvement of Jc values in this system.

Microstructure Properties of Bi0.5Na0.5TiO3-BaZrO3 Piezoelectric Ceramics

2012 ◽  
Vol 151 ◽  
pp. 310-313
Author(s):  
Jenn Sen Lin ◽  
Teng Chin Yu ◽  
Cheng Hsing Hsu ◽  
Ci Jie Huang ◽  
His Wen Yang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid State Route ◽  
Diffraction Patterns ◽  
Conventional Solid State Route ◽  
Scanning Electron

The microstructure properties of the perovskite Bi0.5Na0.5TiO3-BaZrO3 ceramics were prepared with the conventional solid-state route have been investigated. The resultant microstructure properties were analyzed based upon the densification, the X-ray diffraction patterns and scanning electron microscopy. The correlation between the microstructures and the sintering temperature was also examined.

Intracellular structures of rapid frozen biological samples observed by high-resolution low-temperature Scanning Electron Microscopy

1989 ◽  
Vol 47 ◽  
pp. 736-737
Author(s):  
T. Inoué ◽  
H. Koike
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Liquid Nitrogen ◽  
Specimen Preparation ◽  
Chemical Fixation ◽  
Brown Adipose ◽  
Critical Point Drying ◽  
Temperature Scanning ◽  
Scanning Electron

Low temperature scanning electron microscopy (LTSEM) is useful to avoid artifacts such as deformation and extraction, because specimens are not subjected to chemical fixation, dehydration and critical-point drying. Since Echlin et al developed a LTSEM, many techniques and instruments have been reported for observing frozen materials. However, intracellular structures such as mitochondria and endoplasmic reticulum have been unobservable by the method because of the low resolving power and inadequate specimen preparation methods. Recently, we developed a low temperature SEM that attained high resolutions. In this study, we introduce highly magnified images obtained by the newly developed LTSEM, especially intracellular structures which have been rapidly frozen without chemical fixation.[Specimen preparations] Mouse pancreas and brown adipose tissues (BAT) were used as materials. After the tissues were removed and cut into small pieces, the specimen was placed on a cryo-tip and rapidly frozen in liquid propane using a rapid freezing apparatus (Eiko Engineering Co. Ltd., Japan). After the tips were mounted on the specimen stage of a precooled cryo-holder, the surface of the specimen was manually fractured by a razor blade in liquid nitrogen. The cryo-holder was then inserted into the specimen chamber of the SEM (ISI DS-130), and specimens were observed at the accelerating voltages of 5-8 kV. At first the surface was slightly covered with frost, but intracellular structures were gradually revealed as the frost began to sublimate. Gold was then coated on the specimen surface while tilting the holder at 45-90°. The holder was connected to a liquid nitrogen reservoir by means of a copper braid to maintain low temperature.

Criteria for the evaluation of low-temperature Scanning Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 902-903
Author(s):  
Alan Beckett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Conformational Changes ◽  
Chemical Vapour ◽  
List Type ◽  
Dimensional Changes ◽  
Critical Point Drying ◽  
Temperature Scanning ◽  
Scanning Electron

Low temperature scanning electron microscopy (LTSEM) has been evaluated with special reference to its application to the study of morphology and development in microorganisms. A number of criteria have been considered and have proved valuable in assessing the standard of results achieved. To further aid our understanding of these results, it has been necessary to compare those obtained by LTSEM with those from more conventional preparatory procedures such as 1) chemical fixation, dehydration and critical point-drying; 2) freeze-drying with or without chemical vapour fixation before hand.The criteria used for assessing LTSEM for the above purposes are as follows: 1)Specimen immobilization and stabilization2)General preservation of external morphology3)General preservation of internal morphology4)Exposure to solvents5)Overall dimensional changes6)Cell surface texture7)Differential conformational changes8)Etching frozen-hydrated material9)Beam damage10)Specimen resolution11)Specimen life

Magnesium Nitrate as Additive for Synthesis of Mg(OH)2 Nanoparticles

2012 ◽  
Vol 198-199 ◽  
pp. 99-102
Author(s):  
Qing Gang Kong ◽  
Hai Yan Qian
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Magnesium Nitrate ◽  
Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size And Morphology ◽  
Scanning Electron

Magnesium nitrate was used as additive for synthesis of Mg(OH)2 (MH) nanoparticles at low temperature (70°C). Mg(OH)2 nanoparticles have platelet-like structure and approximately 40-60nm in thicknesses. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied to characterize the crystal phase. The supersaturation degree of solution effects the size and morphology of MH nanoparticles.

Low Temperature Combustion Synthesis and Characterization of Pr-CeO2 Doped with Zr Red Ceramic Pigments

2011 ◽  
Vol 399-401 ◽  
pp. 514-518
Author(s):  
Li Dan Yang ◽  
Ming Quan Ye ◽  
Ai Jun Han
Keyword(s):  
Low Temperature ◽  
Combustion Synthesis ◽  
Solid Solutions ◽  
Charge Transfer Band ◽  
Blue Shift ◽  
Fluorite Structure ◽  
Electronic Energy ◽  
Low Temperature Combustion ◽  
Visible Absorption ◽  
Temperature Combustion

New inorganic pigments Ce0.95ZrxPr0.05-xO2(x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) based on CeO2-ZrO2-Pr6O11solid solutions were synthesized by low-temperature combustion synthesis (LCS) method using citric acid as a reductant and metal nitrate as an oxidant. The pigments are CeO2solid solutions doped with praseodymium and zirconium ions, and display colors ranging from dark brown via brick red to bright cream. The prepared pigments were characterized by X-ray powder diffraction, transmission electron microscopy, ultraviolet-visible absorption spectroscopy and colorimetrical measurements. Results show that cubic fluorite structure solid solution of 100 nm Ce0.95ZrxPr0.05-xO2particles can be obtained at 1000 °C. There was an effective absorption of visible blue and green in 600 nm, which is originated from the shift of charge transfer band in CeO2by doping of zirconium and praseodymium ions. Effective red hue was obtained for Ce0.95Zr0.02Pr0.03O2composition, which exhibited better L*, a*,and b* values (57.64, 23.83 and 23.78). The coloring mechanism is based on the introduction of an additional electronic energy level of unpaired 4f electron of the lanthanide ion into the cerianite forbidden band. Furthermore, the doping of Zr in Pr-CeO2system raises the slope of the absorption edge with a blue shift resulting in enhanced lightness. The prepared pigments were prospective to be alternatives for toxic pigments used in coloration of plastics.

Enhanced up-conversion emission in Er3+ doped barium–natrium–yttrium–fluoride phosphor by alkali ions introduction under 1550 nm excitation

CrystEngComm ◽  
2021 ◽  
Author(s):  
Feng Hu ◽  
Qian Wan ◽  
Liping Lu ◽  
Haiying Sun ◽  
Xiyan Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Combustion Synthesis ◽  
Low Temperature Combustion ◽  
Yttrium Fluoride ◽  
Alkali Ions ◽  
Temperature Combustion

Multi-component fluoride phosphors BaxNay-nMnYzF2x+y+3z+3m: Er3+m (M=Li, K) sensitive to 1550 nm were synthesized by the low temperature combustion synthesis (LCS) method. The optimum batch formula was determined by the orthogonal...

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