scholarly journals h-BN-TiO2Nanocomposite for Photocatalytic Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Václav Štengl ◽  
Jiří Henych ◽  
Michaela Slušná
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
High Resolution Electron Microscopy ◽  
Bet Surface Area ◽  
Reactive Black 5 ◽  
Force Microscopy ◽  
Resolution Electron ◽  
Spin Resonance ◽  
Electric Force Microscopy ◽  
Photoinduced Charge ◽  
Hydrolysis Of

h-BN-TiO2nanocomposites were synthesized by the thermal hydrolysis of titanium peroxo-complexes in the presence of exfoliated h-BN. The bulk h-BN was prepared by annealing mixture of boric acid and urea, and high intensity ultrasound was used for its exfoliation. The prepared samples were characterized by X-ray powder diffraction (XRD), infrared spectroscopy, Raman spectroscopy, electron spin resonance (ESR), high resolution electron microscopy, BET surface area, and BJH porosity measurement. The UV-Vis diffuse reflectance spectroscopy was employed to estimate band-gap energies. The photoinduced charge on the surface of h-BN-TiO2nanocomposites was visualized using electric force microscopy (EFM). The photocatalytic activity was determined by azo dyes Orange II and Reactive Black 5 photobleaching. The highest rate constantk= 0.0762 min−1and 0.0164 min−1, under UV and visible light irradiation, respectively, showed sample denoted TiP050BN with moderate concentration of h-BN.

Chemical and Structural Analysis of Nitridated Sapphire

1997 ◽  
Vol 482 ◽  
Author(s):  
Y. Cho ◽  
S. Rouvimov ◽  
Y. Kim ◽  
Z. Liliental-Weber ◽  
E. R. Weber
Keyword(s):  
Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Structural Analysis ◽  
Photoelectron Spectroscopy ◽  
High Resolution Electron Microscopy ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Resolution Electron

AbstractThe incorporation of nitrogen into sapphire substrates during nitridation was studied by xray photoelectron spectroscopy (XPS). An increase in the intensity of nitrogen 1s peak in XPS was observed upon longer nitridation. The surface morphology of the substrates was characterized by atomic force microscopy (AFM). High resolution electron microscopy (HREM) was employed for structural analysis. The cross sectional TEM showed a thin layer of AlN buried between amorphous AlNxO1−x and sapphire. This is the first direct observation of AlN on sapphire. The TEM images show a deeper penetration depth of nitrogen into a longer nitridated sapphire.

Applications of Quantitative Image Analysis to the Description of the Morphology of Boehmite and their Polyurethane Nanocomposites

2006 ◽  
Vol 514-516 ◽  
pp. 1658-1662 ◽  
Author(s):  
Joanna Ryszkowska
Keyword(s):  
Image Analysis ◽  
High Resolution Electron Microscopy ◽  
Quantitative Image Analysis ◽  
Morphological Properties ◽  
Mechanical And Thermal Properties ◽  
Force Microscopy ◽  
Microscopy Technique ◽  
Resolution Electron ◽  
Quantitative Image ◽  
Polyurethane Nanocomposites

This paper presents the application of stereology methods to the description of morphological properties of nanoboehmite and its nanocomposites. Images of boemithe, fracture and cut surface of composites were obtained using high-resolution electron microscopy technique and atomic force microscopy. Quantitative analysis of the fracture structure images obtained with HRSEM technique, allowed us to explain the mechanism of changes of mechanical and thermal properties of polyurethane nanocomposites, as well as allowed to determine relationships between structure characteristics and properties of examined materials. Quantitative image analysis was also found to be useful in comparative analysis of polyurethane nanocomposites structure and structure of boehmite and products of its modification.

Nickel–tungsten bimetallic sulfide nanostructures of fullerene type

2004 ◽  
Vol 19 (7) ◽  
pp. 2176-2184 ◽  
Author(s):  
A. Olivas ◽  
A. Camacho ◽  
M.J. Yacamán ◽  
S. Fuentes
Keyword(s):  
Surface Area ◽  
Metal Sulfide ◽  
Nitrogen Adsorption ◽  
High Resolution Electron Microscopy ◽  
Atomic Ratio ◽  
Bet Surface Area ◽  
Inorganic Fullerene ◽  
Resolution Electron ◽  
Diffraction Patterns ◽  
Bimetallic Sulfide

Bimetallic NiW sulfide nanostructures of the inorganic fullerene-like (IF-like) type were prepared by a chemical method employing ammonium thiotungstate and nickel nitrate as metal-sulfide precursors followed by sulfidation in H2S/H2 at 400 °C. The nanostructures were grown with a Ni excess, at an atomic ratio R = 0.85 (R = Ni/Ni + W). The x-ray diffraction patterns showed poorly crystalline WS2, WO2, NiS, and Ni9S8 phases. High-resolution electron microscopy micrographs revealed the formation of two fullerene-like nanostructures, nickel sulfide nanoparticles and long nanotubes filled with tungsten suboxide, both coated by several WS2 layers. The surface area of 18 m2/g measured by nitrogen adsorption (BET surface-area) revealed that these materials contained micropororosity.

scholarly journals Fast and Straightforward Synthesis of Luminescent Titanium(IV) Dioxide Quantum Dots

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Václav Štengl ◽  
Jiří Henych ◽  
Martin Šťastný ◽  
Martin Kormunda
Keyword(s):  
Quantum Dots ◽  
Photoelectron Spectroscopy ◽  
High Resolution Electron Microscopy ◽  
Fast Method ◽  
X Ray ◽  
Force Microscopy ◽  
Selected Area Electron Diffraction ◽  
Atomic Force ◽  
Resolution Electron ◽  
Close Range

The nucleus of titania was prepared by reaction of solution titanium oxosulphate with hydrazine hydrate. These titania nuclei were used for titania quantum dots synthesis by a simple and fast method. The prepared titanium(IV) dioxide quantum dots were characterized by measurement of X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), high-resolution electron microscopy (HRTEM), and selected area electron diffraction (SAED). The optical properties were determined by photoluminescence (PL) spectra. The prepared titanium(IV) dioxide quantum dots have the narrow range of UV excitation (365–400 nm) and also a close range of emission maxima (450–500 nm).

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

One Million Direct Magnification Microscopy

1971 ◽  
Vol 29 ◽  
pp. 166-167
Author(s):  
J. A. Hugo ◽  
V. A. Phillips
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Illumination Level ◽  
Level Of Detail ◽  
Photographic Emulsion ◽  
Low Contrast ◽  
Fluorescent Screen ◽  
Resolution Electron ◽  
Lattice Images ◽  
Electron Microscopes

A continuing problem in high resolution electron microscopy is that the level of detail visible to the microscopist while he is taking a picture is inferior to that obtainable by the microscope, readily readable on a photographic emulsion and visible in an enlargement made from the plate. Line resolutions, of 2Å or better are now achievable with top of the line 100kv microscopes. Taking the resolution of the human eye as 0.2mm, this indicates a need for a direct viewing magnification of at least one million. However, 0.2mm refers to optimum viewing conditions in daylight or the equivalent, and certainly does not apply to a (colored) image of low contrast and illumination level viewed on a fluorescent screen through a glass window by the dark-adapted eye. Experience indicates that an additional factor of 5 to 10 magnification is needed in order to view lattice images with line spacings of 2 to 4Å. Fortunately this is provided by the normal viewing telescope supplied with most electron microscopes.

Lattice Imaging of Twin, Lath and α/Martensite Boundaries in Duplex Low Carbon Steels

1977 ◽  
Vol 35 ◽  
pp. 118-119
Author(s):  
J. Y. Koo ◽  
G. Thomas
Keyword(s):  
High Resolution Electron Microscopy ◽  
Ferrite Matrix ◽  
Carbon Steels ◽  
Bright Field Image ◽  
Low Carbon ◽  
Lattice Imaging ◽  
Bright Field ◽  
Lattice Image ◽  
New Information ◽  
Resolution Electron

High resolution electron microscopy has been shown to give new information on defects(1) and phase transformations in solids (2,3). In a continuing program of lattice fringe imaging of alloys, we have applied this technique to the martensitic transformation in steels in order to characterize the atomic environments near twin, lath and αmartensite boundaries. This paper describes current progress in this program.Figures A and B show lattice image and conventional bright field image of the same area of a duplex Fe/2Si/0.1C steel described elsewhere(4). The microstructure consists of internally twinned martensite (M) embedded in a ferrite matrix (F). Use of the 2-beam tilted illumination technique incorporating a twin reflection produced {110} fringes across the microtwins.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Electron microscopy of rabbit FC crystals

1983 ◽  
Vol 41 ◽  
pp. 730-731
Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Molecular Replacement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Resolution Electron ◽  
Replacement Technique ◽  
Hydrated Crystal ◽  
Molecular Structure Analysis

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.

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