Search results for "Microscopy"

FTIR Microscopy with Polarized Radiation for the Analysis of Adsorption Processes in Molecular Sieves

1994

FTIR Microscopy with polarized light was used to study the orientation of different molecules in Silicalite I, SAPO-5 and AlPO 4 -5 molecular sieves during the adsorption process and in their equilibrium positions. While the uptake and the equilibrium positions of p-xylene are essentially not influenced by the the framework charge, large differences between AlPO 4 -5 and SAPO-5 are observed with the strongly basic p-nitroaniline molecule.

Microstructural evolution of mullites produced from single-phase gels

2007

The crystalline microstructure of mullites obtained by heating monophasic gels has been investigated. Gels with alumina to silica molar ratio of 3:2 (as in secondary mullite) and 2:1 (as in primary mullite) were prepared by gelling mixtures of aluminium nitrate and tetraethylorthosilicate. Phase transformations were induced by heating the gel precursors, with different final treatment temperatures between 1173 and 1873 K. The mullites formed as a result of thermal treatment were studied by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The crystalline structure (unit-cell parameters) and microstructure were determined from X-ray diffraction pa…

3D cryo-electron microscopy, molecular modelling and structural fitting with recombinant expressed virus like particles as part of drug design

2007

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

Growth and defect studies of CdTe particles

2013

The paper reports the epitaxial growth of cadmium telluride (CdTe) particles by thermal deposition on cleaved planes of (001)NaCl and (001)KBr. Using high resolution transmission electron microscopy and electron diffraction it was shown that CdTe particles could have different orientation and phase (cubic or hexagonal) depending on the substrate temperature. Their most common defects are twins and stacking faults.

Microscopic investigations of homogeneous nucleation in charged sphere suspensions.

2005

We studied the homogeneous nucleation kinetics of an aqueous suspension of charged colloidal spheres under de-ionized conditions. Samples of equilibrium crystalline structure were shear molten and the metastable melt left to solidify after cessation of shear. At low particle number densities n, corresponding to low metastability of the melt, nucleation was monitored directly via video microscopy. We determined the nucleation rates gamma(t) by counting the number of newly appearing crystals in the observation volume per unit time. Using a suitable discrete adaptation of Avrami's [J. Chem. Phys. 7, 1003 (1939); ibid.8, 212 (1940); ibid.9, 177 (1941)] model for solidification via homogeneous n…

Quaternary structure and molecular model of a 4x6mer arthropod hemocyanin in oxygenated and deoxygenated states by 3D cryo-electron microscopy

2007

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

Electron Diffraction and Imaging of Uncompressed Monolayers of Amphiphilic Molecules on Vitreous and Hexagonal Ice

1993

A new approach is described for probing domains of ordered self-assemblies of amphiphilic monolayers at the aqueous solution interface. The method has potential importance for the study of membrane structure, Langmuir-Blodgett films, and nucleation processes of two-and three-dimensional crystals. Electron diffraction (ED) patterns indicative of two-dimensional crystalline self-assembly were obtained from samples, which were examined by cryo-electron microscopy, of monolayers of water-insoluble amphiphiles on vitrified aqueour substrates. The apparent hexagonal symmetry of an ED pattern from a C(16)H(33)OH monolayer was interpreted in terms of multiple twinning. Monolayers of the CL(31)H(63)…

DOMAIN AND MOLECULAR SUPERLATTICE STRUCTURE OF DODECANETHIOL SELF-ASSEMBLED ON AU(111)

1994

Annealed organic monolayers of dodecanethiol (CH3(CH2)11SH) self-assembled on Au(111) have been investigated by scanning tunnelling microscopy. By using very high tunnelling resistances (TOMEGA) we find evidence of well-ordered molecular domains at room temperature and observe two different types of c(4 x 2) superlattice structures with the same rectangular unit cell. In contrast to theoretical calculations each unit cell contains four inequivalent molecules. Possible reasons for this discrepancy are discussed.

ChemInform Abstract: Analysis of Active Site Distribution in ZSM-5 Crystals by IR Microscopy.

2010

Synchrotron Radiation-Based Micro-XANES and Micro-XRF Study of Unsuccessfully Produced Egyptian Blue from the Late Hellenistic Production Site of Kos…

2021

International audience; This paper examines the production technology of Egyptian blue, an ancient artificial pigment, through the investigation of an unsuccessfully produced pellet derived from the Hellenistic production site of Kos (Dodecanese, Greece). This heterogeneous material was investigated by a combination of laboratory and synchrotron radiation-based (SR) techniques: scanning electron microscopy coupled with energy-dispersive Xray spectrometry, micro-Raman spectroscopy, high-resolution SR micro-X-ray fluorescence spectroscopy, and SR micro-X-ray absorption near-edge structure spectroscopy (XANES), at the ID21 beamline of the European Synchrotron Radiation Facility. Principal comp…