Selected Area Electron Diffraction Methods Research Articles

STRUCTURAL ANALYSIS OF ZnO/GO NANOCOMPOSITE AND ITS IMPACT ON MUTATED AND NON-MUTATED SOD1 PROTEINS THROUGH DOCKING STUDIES

The interaction of nanocomposite (ZnO/GO) with biomolecules like Protein SOD1 (which is related to neurodegenerative disorders) as a result of many physiological changes in that protein leads to the study of various neurodegenerative disorders. In this work, we investigate the mutated and non-mutated SOD1 proteins (which are responsible for many neurodegenerative diseases) that were suggested to interact with the ZnO-GO composite, both compounds having extraordinary bioactive performances against neurodegenerative disorders. Morphological studies of ZnO-GO nanocomposite were studied by using innovative spectroscopy techniques such as XRD (X-ray diffraction), SAED (selected area electron diffraction), EDX, and TEM (transmission electron microscopy) methods. Impacts on SOD1 proteins, both mutated and non-mutated, such as binding energy, bonding and non-bonding interaction, and docking score studies, were analyzed using docking software.

A new highly powered supercapacitor electrode of advantageously united ferrous tungstate and functionalized multiwalled carbon nanotubes

The disadvantages that prevent supercapacitors from swapping batteries in most of the applications are linear discharge voltage, low specific energy, and high cost. Here, we report the fabrication of a new nanocomposite electrode by strategically combining ferrous tungstate and functionalized multiwalled carbon nanotubes (FeO4W/f-MWCNTs) hydrothermally for high-performance supercapacitors. This supercapacitor electrode shows specific capacitance as high as 875 Fg−1. The cycle tests show capacitance retention of 89.17% after huge 10,000 cycles in three electrode system. Further, a symmetric supercapacitor device made of FeO4W/f-MWCNTs delivers a high specific capacitance with good capacitance retention. Such a discovery of a novel electrode certainly paves way for the development of advanced nanocomposite electrodes for energy storage applications with substantial improvement in charge time, specific power, cycle life, and safety. Analytical techniques such as ultraviolet–visible spectroscopy and Fourier transform infrared spectroscopy confirm the presence of functionalities in the composite, whereas thermogravimetric analysis of the nanocomposite reveal better thermal stability compared to its counterparts. The crystallinity of the composite is ascertained by X-ray diffraction technique. The interplanner spacing (dhkl) in the nanomaterial is measured from high-resolution transmission electron microscopy and selected area electron diffraction methods. Energy-dispersive X-ray analysis is used for elemental analysis.

Structure and Phase Transformation in the Giant Magnetostriction Laves-Phase SmFe2.

As one class of the most important intermetallic compounds, the binary Laves-phase is well-known for its abundant magnetic properties. Samarium-iron alloy system SmFe2 is a prototypical Laves compound that shows strong negative magnetostriction but relatively weak magnetocrystalline anisotropy. SmFe2 has been identified as a cubic Fd3̅m structure at room temperature; however, the cubic symmetry, in principle, does not match the spontaneous magnetization along the [111]cubic direction. Here we studied the crystal structure of SmFe2 by high-resolution synchrotron X-ray powder diffraction, X-ray total scattering, and selected-area electron diffraction methods. SmFe2 is found to adopt a centrosymmetric trigonal R3̅m structure at room temperature, which transforms to an orthorhombic Imma structure at 200 K. This transition is in agreement with the changes of easy magnetization direction from [111]cubic to [110]cubic direction and is further evidenced by the inflection of thermal expansion behavior, the sharp decline of the magnetic susceptibility in the field-cooling-zero field-cooling curve, and the anomaly in the specific heat capacity measurement. The revised structure and phase transformation of SmFe2 could be useful to understand the magnetostriction and related physical properties of other RM2-type pseudocubic Laves-phase intermetallic compounds.

On the structures of the rare-earth metal germanides from the series REAl1-xGe3 (RE = Nd, Sm, Gd, Tb, Dy, Ho; 0.6 < x < 0.9). A tale of vacancies at the Al sites and the concomitant structural modulations.

A series of ternary rare-earth metal aluminum germanides with the general formula REAl1-xGe3 (RE = Nd, Sm, Gd, Tb, Dy, and Ho; 0.6 < x < 0.9) have been synthesized by direct fusion of the corresponding elements. Their structures have been characterized by single-crystal X-ray diffraction and selected area electron diffraction methods. The average structure for all members is a representative of the orthorhombic SmNiGe3-type structure (Pearson symbol oS20, space group Cmmm), where the Al atoms occupy the Ni site, and the deep off-stoichiometry is due to statistical vacancies at this position. Considering long-range ordering of the vacancies, a monoclinic and a different orthorhombic structure, which represent idealized ordered variants, are possible, and the structural evolution depending on the nature of the rare-earth metals and the amount of vacancies at the aluminum site are discussed. Commensurate and incommensurate structural modulations based on these parent structures are also observed by electron diffraction, attesting to the great structural complexity in these systems. Magnetic susceptibility measurements are presented and discussed, along with the results from electronic band-structure calculations.

One Pot Synthesis of Exchange Coupled Nd&lt;SUB&gt;2&lt;/SUB&gt;Fe&lt;SUB&gt;14&lt;/SUB&gt;B/&lt;I&gt;α&lt;/I&gt;-Fe by Pechini Type Sol–Gel Method

In this work, a combination of nanoparticles of Nd2Fe14B hard magnetic phase and alpha-Fe soft magnetic phase were synthesized by one pot chemical synthesis technique using sol-gel method. A gel of Nd-Fe-B was prepared using NdCl3 x 6H2O, FeCl3 x 6H2O, H3BO3, citric acid, and ethylene glycol by pechini type sol-gel method. The gel was subsequently calcined and annealed to obtain the mixed oxide powders. The produced metal oxide particles were identified with XRD, SEM, TEM to obtain the crystal structure, shape and domain structure of them. The nanoparticles of mixed phase of Nd2Fe14B/alpha-Fe were obtained from these oxides by a process of reduction-diffusion in vacuum by employing CaH2 as reducing agent. During this process it was optimized by controlling temperature, reaction time and concentration of the reducing agent (CaH2). The phase formation of Nd2Fe14B was resulted by the direct diffusion of NdH2, Fe and B. The magnetic property of produced hard and soft phases was successfully identified with vibrating sample magnetometer (VSM). The mixed domains of the hard and soft phases were identified with selected area electron diffraction method (SAED) patterns.

Strain mapping in selected area electron diffraction method combining a Cs-corrected TEM with a stage scanning system

A novel strain mapping method with high spatial resolution is proposed on the basis of the selected area electron diffraction. It consists of a Cs-corrected transmission electron microscope (TEM) and a stage scanning system. The Cs-corrected TEM sufficiently narrows a selected area aperture without image selection error and enables us to obtain diffraction patterns from selected nanometer-scale regions with a parallel beam. The diffraction spots are very sharp due to the parallel beam, thus facilitating the strain measurement. The stage scanning system for controlling the sample stage with piezoelectric actuators can scan an electron beam over an area without changing the electron beam optics. I critically examined the validity and flexibility of this method by using a current strain-induced semiconductor device.

Microstructural characterization of TFA-MOD processed Y1−xGdxBa2Cu3O7−y with BaZrO3

Y1−xGdxBa2Cu3O7−y with BaZrO3 film was fabricated on CeO2 buffered LaMnO3/ion beam assisted deposition-MgO/Gd2Zr2O7/Hastelloy C276TM substrates by the metal organic deposition process using trifluoroacetates. Both microstructural and analytical characterizations were performed by transmission electron microscopy with selected area electron diffraction method and energy dispersive X-ray spectroscopy. The thickness of Y1−xGdxBa2Cu3O7−y with BaZrO3 film was found approximately 700nm and the film was composed of c-axis oriented Y1−xGdxBa2Cu3O7−y grains. Several types of particles, (Y,Gd)2Cu2O5, CuO and BaZrO3, were formed within the Y1−xGdxBa2Cu3O7−y film, whose sizes were about 100–200nm for (Y,Gd)2Cu2O5 and CuO particles, and about 10–20nm for BaZrO3 particles, respectively. In the Y1−xGdxBa2Cu3O7−y film, (Y,Gd)2Cu2O5 and CuO particles were dispersed heterogeneously, whereas BaZrO3 nanoparticles were found dispersed homogeneously with random orientation. In addition, electron tomographic observation was carried out to attain the three-dimensional information of polyhedral BaZrO3 nanoparticles.

Thermal phase transition behavior of lipid layers on a single human corneocyte cell

We have improved the selected area electron diffraction method to analyze the dynamic structural change in a single corneocyte cell non-invasively stripped off from human skin surface. The improved method made it possible to obtain reliable diffraction images to trace the structural change in the intercellular lipid layers on a single corneocyte cell during heating from 24°C to 100°C. Comparison of the results with those of synchrotron X-ray diffraction experiments on human stratum corneum sheets revealed that the intercellular lipid layers on a corneocyte cell exhibit essentially the same thermal phase transitions as those in a stratum corneum sheet. These results suggest that the structural features of the lipid layers are well preserved after the mechanical stripping of the corneocyte cell. Moreover, electron diffraction analyses of the thermal phase transition behaviors of the corneocyte cells that had the lipid layers with different distributions of orthorhombic and hexagonal domains at 24°C suggested that small orthorhombic domains interconnected with surrounding hexagonal domains transforms in a continuous manner into new hexagonal domains.

Structural and Chemical Features of Silicon Nanocrystallites in Nanocrystalline Hydrogenated Silicon Thin Films

Hydrogenated nanocrystalline silicon (nc-Si:H) thin films were deposited on Si wafers at room temperature by plasma-enhanced chemical vapor deposition (PECVD): a mixture of SiH4 and H2 was introduced into the evacuated reaction chamber. The films were postdeposition annealed at temperatures of 400–1100°C. The silicon nanocrystallites (nc-Si) in the films range from ∼4.0 to ∼8.0 nm in size, depending on the hydrogen flow rates as well as the annealing conditions. The relative fractions of the Si-H3, Si-H2, and Si-H bonds in the nc-Si:H films varied sensitively with the heat-treatment conditions. Local radial distribution function (RDF) analysis of the films was performed by using selected area electron diffraction methods. A model for the nanostructure of the nc-Si:H films was suggested to take into account the variation in the size and chemical bonds of the nanocrystallites as well as the amorphous matrix.

Mössbauer transmission and back scattered conversion electron study of Fe nanowires encapsulated in multiwalled carbon nanotubes

Fe 57 transmission Mössbauer spectroscopy (TMS) and back scattered conversion electron Mössbauer spectroscopy (CEMS) measurements were carried out on Fe-filled multiwalled carbon nanotubes (Fe-MWCNTs) grown by chemical vapor deposition with ferrocene as precursor. Samples of Fe-MWCNTs material deposited on the inner wall of the quartz tube reactor and samples of aligned Fe-MWCNTs grown perpendicularly to the oxidized Si substrate were characterised by the TMS method. The data show that Fe phases encapsulated within the carbon nanotubes comprise α-Fe, γ-Fe, and Fe3C in different percentage ratio depending on the sample preparation. These results are in a good accordance with the previously measured magnetic characteristics and with the structural data found by x-ray diffraction as well by selected area electron diffraction methods and allow a new complementary characterization of the Fe(Fe-alloy)-MWCNT systems. The CEMS method applied for the characterization of metal containing MWCNTs reveals that close to the top surface of the aligned Fe-MWCNTs samples only the γ-Fe phase is found. This technique shows an additional potential for further investigation of the spatial distribution of the crystalline phases in the depth of aligned Fe-MWCNT samples.

Synthesis, structure and magnetism of homologous series of polycrystalline cobalt alkane mono- and dicarboxylate soaps.

Carboxylate-bridged chain complexes of Co(II) (the diaquacobalt(II) mono- and ,-dialkanoates) form two homologous series of layered compounds which have been fully characterised both structurally and magnetically. The crystal structures of two selected members, [Co[CH3(CH2)10COO]2(H2O)2] and [Co[CH3(CH2)18COO]2(H2O)2], have been solved by X-ray powder diffraction and selected-area electron diffraction methods, and refined by the Rietveld technique. Crystal data: monoclinic, P 2(1)/a; a=9.688(1), b=7.5495(9), c=37.281(5) A, =96.70(3) primary, Z=4; and monoclinic, P 2(1)/a; a=9.7260(7), b=7.5477(7), c=57.53(1) A, =94.66(4) primary, Z=4, respectively. Their isomorphous structures contain layers of octahedral diaquacobalt(II) ions bonded to two chemically inequivalent alkanoates, one chelating and one bridging two Co atoms about 6.3 A apart, thus confirming the rare anti-anti conformation mode of the -RCOO groups recently proposed for diaquacobalt(II) ,-dodecanedioate. Extensive magnetic characterisation allowed estimation of the feeble antiferromagnetic coupling, which is weaker in the mono- than in the dialkanoate series.

Structural Modulations in Monoclinic Tricalcium Silicate Solid Solutions Doped with Zinc Oxide, M(I), M(II), and M(III)

Structural modulations in solid solutions of C3S doped with various amounts of ZnO were investigated via the selected‐area electron diffraction method. Three monoclinic modifications (M(I), M(II), and M(III)) were identified in the solid solutions. The modifications had pseudohexagonal subcells that were modulated to form supercells. Coordinates of the reflections attributable to the supercells could be expressed by the following linear combinations of vectors of the reciprocal lattices: m1(−2a*/5.4 + 2b*/5.4 − 7c*/5.4) for M(I), m2(−a*/5 +b*/5 −c*) for M(II), and m3(−a*/6 +b*/6 + 7c*/6) for M(III), m1 and m2=±1 and ±2, and m3=±1, ±2, and ± 3. All the monoclinic modifications possessed structural modulations of a one‐dimensional type. The modulation waves could be detected as wavy contrasts by high‐resolution transmission electron microscopy.

Aging and composition dependence of electron diffraction patterns in Y 2O 3-stabilized ZrO 2: Relationship between crystal structure and conductivity

Changes in the crystal structures of Y 2O 3-stabilized ZrO 2, an oxygen ion conductor, with aging were investigated by high-resolution transmission electron microscopy and selected area electron diffraction method. The changes with aging were analyzed mainly by calling attention to superlattice reflections and diffuse scattering seen on electron diffraction patterns, and the results clarified the relationship between changes in the crystal structures and conductivity. It is concluded that various phenomena due to aging at relatively lower temperatures are caused by short-range ordering of oxygen ion vacancies to Zr ions, which occurs in order to relax the anisotropy of periodical lattice distortion. Also, changes in the crystal structures occurring with changing dopant concentrations were investigated at the same time. As a result, it is concluded that the changes in crystal structure responsible for the decrease in conductivity associated with increasing dopant concentration are caused by short-range ordering of oxygen ion vacancies in order to relax the anisotropy in strain fields, similarly to those due to aging.

Quenching C60 fullerene into diamond in the Fe-C alloy system by laser treatment

Diamond particles dispersed in the Fe-C alloy system were obtained by CO2 continuous laser-induced quenching of C60/C70 coatings on 45# carbon steel (C content: 0.45 pct). Rockwell hardness, electron microscopy, and selected area electron diffraction methods had been used to analyze the products (namely, fullerite). The results indicated that the so-made fullerite, which reached average Rockwell hardness of 65.4, contained a great deal of polygonal crystallites on the order of 0.1 (μm). Most of them were well-faceted cubic diamond. Other new phases were also formed in the process. The possible transition mechanism was discussed.

A Study of 90° Ferroelectric Domains in Potassium Tantalate Niobate Crystals by Means of Transmission Electron Microscopy

By flux method, potassium tantalate niobate crystals with 46% Nb contents were prepared. In this material 90° a-type domains with (011) and (011̄) walls were observed by a transmission electron microscope, and the nature of fringe patterns associated with these domain walls was analysed. According to the extinction rules for the domain walls, the displacement vector R along <011̄> direction can be determined. Finally, using a selected area electron diffraction method, we examined the crystallographic character of these 90° domains and defined the ratio of lattice parameters c to a.

Selected area electron diffraction and energy dispersive X-ray analysis for the identification of asbestos fibres, a comparison

Transmission electron microscope selected area electron diffraction patterns and scanning electron microscope energy dispersive X-ray micro-analysis spectra from thirteen silicate minerals are compared. This was done to determine the relative viability of the two methods specifically for differentiating asbestos from non-asbestos minerals. Six asbestos and seven non-asbestos sheet and chain silicates were studied and the results from the two electron microscope methods are presented as micrographs, electron diffraction patterns and X-ray micro-analysis elemental spectra. The results show that only the selected area electron diffraction method is reliable in differentiating the six asbestos minerals from most of the randomly selected non-asbestos minerals.

Selected Area Diffraction of Very Small Specimen Areas using Improved Lattice Imaging Methods

In conventional selected area electron diffraction methods, the lower limit of the selected specimen area is usually of the order of 10,000 Å. For many applications – including the detailed study of very early stages of thin film growth – it is imperative, however, to (a) study the crystallography of much smaller specimen areas, and (b) to obtain selected area orientation information from extremely thin diffracting specimens where the ratio of electron scattering specimen mass to that of the supporting film is so low that no useful electron diffraction pattern can be obtained.

Electron Microscopic Observation on Sulphuration of Vacuum-Deposited Silver Films

Sulphuration process of vacuum-deposited silver films and orientation relationship between silver and its sulphide were examined by transmission electron microscopy and selected area electron diffraction method. Acanthite (β-Ag2S) crystals grew with a relation of (012)Ag2S//(001)Ag and <100>Ag2S//<100>Ag on the (001) single-crystal surface of silver, and with a relation of (012)Ag2S//(111)Ag and <521̄>Ag2S//<101̄>Ag on the (111) surface. The sulphide crystals were nucleated at random over the silver surface and the dislocations in silver did not seem to play any special role in the nucleation of sulphide. The crystals which appeared at stacking faults or twins were larger than those formed at the other sites. The films were often broken-down and transparent regions were observed. The sulphide crystals became such thick crystals as did not transmit the 100 kV electron beam. The results seem to show that a surface diffusion of silver is very fast even at room temperature and a factor controlling the growth of sulphide crystals.

Electron Microscopy and Diffraction Studies of Vanadium Pentoxide Sols

Vanadium pentoxide sols were prepared by the method using the cation exchange resin and Biltz method and studied with an electron microscopy and diffraction method. The sol prepared by the ion exchanger contained capillary crystals and the particles did not grow by aging. The Biltz sol grew like fibre by aging. These sols were confirmed to be vanadium pentoxide by the electron diffraction.The fibres of Biltz sol, about one year old, could be arranged in parrallel with each other and was investigated by the selected area electron diffraction method. The diffraction pattern was a typical fibre pattern with many layer lines and the fibre axis was confirmed to be b-axis.