scholarly journals MORPHOLOGY AND COMPOSITION OF THE INTERFACE BOUNDARY OF SODIUM CHLORIDE SINGLE CRYSTALS WITH LEAD

Author(s):  
Аминат Хусеновна Дышекова ◽  
Ахмед Мацевич Кармоков ◽  
Асламбек Идрисович Хасанов ◽  
Рустам Мухамедович Калмыков ◽  
Замир Валериевич Шомахов

Методами электронной микроскопии и рентгеноспектрального анализа исследована межфазная граница раздела жидкого свинца с хлоридом натрия после охлаждения и разрыва контакта. На поверхностях разрыва образцов обнаружено накопление поверхностно-активных примесей, содержащихся как объеме свинца, так и в хлориде натрия. Как показывают результаты рентгеноспектрального анализа, содержание примесей на поверхности подложки хлорида натрия превышает объемное содержание на несколько порядков. На поверхности свинца также наблюдается значительное накопление примесей кремния и индия. В исследованных образцах наблюдается анизотропия растекания жидкого свинца по поверхности монокристаллов хлорида натрия. Линия разрыва, затвердевшей капли свинца с монокристаллической поверхностью хлорида натрия ориентации (110), заметно отклоняются от круга. Кроме того, на электронно-микроскопическом изображении межфазной поверхности свинца после отрыва от подложки хлорида натрия ориентации (100), наблюдаются участки в виде «сигары», в которых обнаружено накопление примесей. Данные участки имеют ориентации, совпадающие с кристаллографическим направлением подложки. The interface between liquid lead and sodium chloride after cooling and breaking the contact was investigated by the electron microscopy and X-ray spectral analysis. Accumulation of surface-active impurities, contained both in the bulk of lead and in sodium chloride was found on the fracture surface of the samples. As shown by the results of the X-ray diffraction analysis, the content of impurities on the surface of the sodium chloride substrate exceeds the bulk content by several orders of magnitude. A significant accumulation of silicon and indium impurities is also observed on the lead surface. Anisotropy of spreading of liquid lead over the surface of sodium chloride monocrystals is observed in the studied samples. The separation line of a solidified lead droplet on the surface of sodium chloride with orientation (110) deviates noticeably from a circle. In addition, on the electron microscopic image of the lead interface after detachment from the substrate of sodium chloride of orientation (110), there are areas in the form of a «cigar», in which the accumulation of impurities was detected. The orientation of these regions coincides with the crystallographic direction of the substrate.

Author(s):  
S. W. Hui ◽  
T. P. Stewart

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.


1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.


1993 ◽  
Vol 317 ◽  
Author(s):  
R.M. Osgood ◽  
B.M. Clemens ◽  
R.L. White ◽  
S. Brennan

ABSTRACTGrazing incidence and asymmetric X-ray diffraction were used to measure the stress and strain state of Fe(110)/Mo(110) Multilayers. The highest stress in the Fe constituent of the multilayer was along the [110] in-plane direction and was due to interaction with the substrate. The Magnetic anisotropy of the Fe Multilayer constituent was measured and the magnetic surface anisotropy, which favored in-plane [001] magnetization, was deduced. In contrast, the magnetic surface anisotropy of a single layer of Fe on W preferred in-plane [110] magnetization, in agreement with the Néel Model.


Author(s):  
А.Я. Пак ◽  
Г.Я. Мамонтов

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.


Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3249 ◽  
Author(s):  
Satoshi Idenoue ◽  
Yoshitaka Oga ◽  
Daichi Hashimoto ◽  
Kazuya Yamamoto ◽  
Jun-ichi Kadokawa

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.


2012 ◽  
Vol 488-489 ◽  
pp. 666-670 ◽  
Author(s):  
M. Hussain Beevi ◽  
S. Vignesh ◽  
T. Pandiyarajan ◽  
P. Jegatheesan ◽  
R. Arthur James ◽  
...  

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.


2008 ◽  
Vol 72 (1) ◽  
pp. 217-220 ◽  
Author(s):  
H. P. Vu ◽  
S. Shaw ◽  
L. G. Benning

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.


2012 ◽  
Vol 424-425 ◽  
pp. 780-783
Author(s):  
Heng Li

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.


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