Geneses and evolutions of iron-bearing minerals in banded iron formations of >3760 to ca. 2200 million-year-old: Constraints from electron microscopic, X-ray diffraction and Mössbauer spectroscopic investigations

2017 ◽  
Vol 289 ◽  
pp. 1-17 ◽  
Author(s):  
Si Sun ◽  
Yi-Liang Li
Keyword(s):  
X Ray Diffraction ◽  
Banded Iron Formations ◽  
Electron Microscopic ◽  
X Ray ◽  
Spectroscopic Investigations ◽  
Iron Formations ◽  
Iron Bearing

Direct visualization of phase-separated domains in lipid membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 290-291
Author(s):  
S. W. Hui ◽  
T. P. Stewart
Keyword(s):  
Lipid Membranes ◽  
Structural Information ◽  
Freeze Fracture ◽  
Biological Molecules ◽  
Vacuum Drying ◽  
Direct Visualization ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Hydrocarbon Chains

Direct electron microscopic study of biological molecules has been hampered by such factors as radiation damage, lack of contrast and vacuum drying. In certain cases, however, the difficulties may be overcome by using redundent structural information from repeating units and by various specimen preservation methods. With bilayers of phospholipids in which both the solid and fluid phases co-exist, the ordering of the hydrocarbon chains may be utilized to form diffraction contrast images. Domains of different molecular packings may be recgnizable by placing properly chosen filters in the diffraction plane. These domains would correspond to those observed by freeze fracture, if certain distinctive undulating patterns are associated with certain molecular packing, as suggested by X-ray diffraction studies. By using an environmental stage, we were able to directly observe these domains in bilayers of mixed phospholipids at various temperatures at which their phases change from misible to inmissible states.

scholarly journals Получение карбида бора в низковольтной электрической дуге постоянного тока, инициированной в открытом воздушном пространстве

2018 ◽  
Vol 44 (14) ◽  
pp. 26 ◽  
Author(s):  
А.Я. Пак ◽  
Г.Я. Мамонтов
Keyword(s):  
Boron Carbide ◽  
Arc Discharge ◽  
Electron Microscopic Examination ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Vacuum Equipment ◽  
X Ray ◽  
Gas Atmosphere ◽  
Average Size ◽  
Carbide Particles

AbstractWe describe a method of obtaining ultrafine boron carbide (B_13C_2) powder using the effect of a dc electric arc on a mixture of initial reactants containing carbon and boron. A peculiarity of the proposed method is that it can be implemented using arc discharge operating in open air without any vacuum equipment and protective inert gas atmosphere. X-ray diffraction data showed that the synthesized product in the general case contained three crystalline phases: boron carbide (B_13C_2), graphite (C), and boron oxide (B_2O_3). Electron-microscopic examination showed that the average size of boron carbide particles ranged from ~50 nm to ~2 μm.

scholarly journals Preparation of Reswellable Amorphous Porous Celluloses through Hydrogelation from Ionic Liquid Solutions

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3249 ◽  
Author(s):  
Satoshi Idenoue ◽  
Yoshitaka Oga ◽  
Daichi Hashimoto ◽  
Kazuya Yamamoto ◽  
Jun-ichi Kadokawa
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Liquid Solutions ◽  
Scanning Electron Microscopic ◽  
Porous Morphology ◽  
Scanning Electron

In this study, we have performed the preparation of reswellable amorphous porous celluloses through regeneration from hydrogels. The cellulose hydrogels were first prepared from solutions with an ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl), in different concentrations. Lyophilization of the hydrogels efficiently produced the regenerated celluloses. The powder X-ray diffraction and scanning electron microscopic measurements of the products suggest an amorphous structure and porous morphology, respectively. Furthermore, the pore sizes of the regenerated celluloses, or in turn, the network sizes of cellulose chains in the hydrogels, were dependent on the concentrations of the initially prepared solutions with BMIMCl, which also affected the tensile mechanical properties. It was suggested that the dissolution states of the cellulose chains in the solutions were different, in accordance with the concentrations, which representatively dominated the pore and network sizes of the above materials. When the porous celluloses were immersed in water, reswelling was observed to regenerate the hydrogels.

Synthesis and Antifungal Studies on CuO Nanostructures

2012 ◽  
Vol 488-489 ◽  
pp. 666-670 ◽  
Author(s):  
M. Hussain Beevi ◽  
S. Vignesh ◽  
T. Pandiyarajan ◽  
P. Jegatheesan ◽  
R. Arthur James ◽  
...  
Keyword(s):  
Sol Gel ◽  
Diffusion Method ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Disk Diffusion Method ◽  
Spectroscopic Measurements ◽  
Antifungal Activities ◽  
X Ray ◽  
Vibrational Bands ◽  
Anti Fungal

We report, synthesis and antifungal activities of CuO nanoparticles. Particles are prepared through sol-gel method. X-ray diffraction studies show the particles are monoclinic (crystalline) in nature. Scanning electron microscopic measurements are carried out to understand the morphology of the prepared particles. Energy-dispersive X-ray spectroscopic measurements show that the prepared particles containing Cu and O. To identify the local structure of the particles Fourier transform infra red (FTIR) spectroscopic measurements were carried out showing vibrational bands of Cu-O and O-H band. Anti fungal studies were performed on the set of fungal using disk diffusion method and found that the prepared particles are suitable for antifungal activities.

Transformation of ferrihydrite to hematite: anin situinvestigation on the kinetics and mechanisms

2008 ◽  
Vol 72 (1) ◽  
pp. 217-220 ◽  
Author(s):  
H. P. Vu ◽  
S. Shaw ◽  
L. G. Benning
Keyword(s):  
High Resolution ◽  
Growth Mechanism ◽  
Elevated Temperatures ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Time Resolved ◽  
X Ray ◽  
Resolution Electron ◽  
Stage Process

AbstractThe kinetics and mechanisms of the transformation of 2-line ferrihydrite (FH) to hematite (HM), in the presence of Pb at elevated temperatures and high pH condition, were elucidated using synchrotron-based,in situenergy dispersive X-ray diffraction (EDXRD). The time-resolved diffraction data indicated that HM crystallization occurred via a two-stage process. Based on the EDXRD data, combined with high-resolution electron microscopic images, an aqueous-aided 2D growth mechanism is proposed for both HM crystallization stages.

Study of an Inorganic Ion Exchanger Li1.2Zn0.9PO4

2012 ◽  
Vol 424-425 ◽  
pp. 780-783
Author(s):  
Heng Li
Keyword(s):  
Exchange Capacity ◽  
Ion Exchanger ◽  
Column Test ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
X Ray ◽  
Inorganic Ion Exchanger ◽  
Inorganic Ion ◽  
Composition Structure

New complex inorganic ion exchanger Li1.2Zn0.9PO4is synthesized. Chemical composition, structure and some related properties and complex mechanism of this ion exchanger are investigated by electron microscopic, X-ray diffraction and chemical methods. The ion exchange behavior of Li1.2Zn0.9PO4has been studied in detail. Results of column test indicated, that the exchange capacity obtained from tests for Li+in 0.1mol /L HNO3solution is 6.3mmol/g.

Synthesis of nanometer-sized particles of barium orthotitanate prepared through a modified reverse micellar route: Structural characterization, phase stability and dielectric properties

2004 ◽  
Vol 19 (10) ◽  
pp. 2905-2912 ◽  
Author(s):  
Tokeer Ahmad ◽  
Ashok K. Ganguli
Keyword(s):  
Martensitic Transition ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Microscopic Studies ◽  
Size Of Particles ◽  
Reverse Micellar

Nanoparticles of barium orthotitanate (Ba2TiO4) was obtained using microemulsions (avoiding Ba-alkoxide). Powder x-ray diffraction studies of the powder after calcining at 800 °C resulted in a mixture of orthorhombic (70%) and monoclinic (30%) phases. The high-temperature orthorhombic form present at 800 °C was due to the small size of particles obtained by the reverse micellar route. Pure orthorhombic Ba2TiO4 was obtained on further sintering at 1000 °C with lattice parameters a = 6.101(2) Å, b =22.94(1) Å, c = 10.533(2) Å (space group, P21nb). The particle size obtained from x-ray line broadening studies and transmission electron microscopic studies was found to be 40–50 nm for the powder obtained after heating at 800 °C. Sintering at 1000 °C showed increase in grain size up to 150 nm. Our studies corroborate well with the presence of a martensitic transition in Ba2TiO4. The dielectric constant was found to be 40 for Ba2TiO4 (at 100 kHz) for samples sintered at 1000 °C. The dielectric loss obtained was low (0.06) at 100 kHz.

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