Search results for "solid"
showing 10 items of 3575 documents
Nuclear Magnetic Resonance and Electron Spin Resonance Spectroscopy
2001
The article contains sections titled: 1. Introduction 2. Principles of Magnetic Resonance 2.1. Nuclear and Electronic Properties 2.2. Nuclei and Electrons in a Stationary Magnetic Field 2.3. Basic Principles of the NMR and ESR Experiments 2.4. Relaxation 3. High-Resolution Solution NMR Spectroscopy 3.1. The NMR Experiment 3.1.1. Continuous Wave Methodology 3.1.2. Fourier Transform Methodology 3.2. Spectral Parameters 3.2.1. Chemical Shift 3.2.2. Spin - Spin Coupling 3.2.3. Signal Intensity 3.2.4. Relaxation Times 3.3. NMR and Structure 3.3.1. Hydrogen (1H and 2H) 3.3.2. Carbon (13C) 3.3.3. Fluorine (19F) 3.3.4. Phosphorus (31P) 3.3.5. Nitrogen (14N and 15N) 3.3.6. Oxygen (17O) 3.3.7. Silico…
Education for development in the university context. Why and for what?
2021
La educación para el desarrollo se ha venido popularizando progresivamente en las universidades españolas en paralelo con la extensión de la cooperación para el desarrollo entre estas. La educación para el desarrollo se ha visto como una oportunidad para promover el compromiso social de la Universidad y fomentar valores de solidaridad y justicia a través de la formación universitaria. La educación para el desarrollo ha puesto de relieve el componente educativo de la Universidad, a menudo subsumido por el afán formativo. Sin embargo, el alcance de la educación para el desarrollo y, sobre todo, su transversalización en los programas de estudio universitarios siguen siendo muy limitados. El ob…
Hydro-mechanical behaviour of shallow Opalinus Clay shale
2019
In Switzerland, Opalinus Clay shale has been selected as the host formation for radioactive waste disposal. The minimum required depth of the repository is related to the long-lasting isolation required for the disposal (1 million years). During this period, possible erosion scenarios affecting the repository need to be analysed. Opalinus Clay from shallow depths (< 70 m) was sourced from a borehole in Northern Switzerland, where the formation was affected by a considerable exhumation process. This work aims to investigate the impact of the mentioned phenomenon on the hydro-mechanical behaviour of Opalinus Clay through one-dimensional consolidation and permeability measurements. Laboratory …
Imaging to study solid tumour origin and progression: lessons from research and clinical oncology
2017
Biomedical imaging in recent decades has clarified our understanding of normal and pathological cellular processes in vivo. In particular, this approach recently provided insights into processes occurring at a molecular or genetic level rather than at the anatomical level. The evolution of this discipline by engineering have led to its integration into biomedical research to (1) increase sensitivity and resolution imaging and to (2) improve tissue and cell specificity. Currently, imaging approaches are used in three different biomedical areas: (a) identification of cellular processes in physiological and disease state; (b) in vivo single-cell imaging; and (c) identification of new prognosti…
ChemInform Abstract: “Supramolecular” Solid-State Chemistry: Interpenetrating Diamond-Type Frameworks of U4+ Ions Linked by S,S′-Bidentate P2S2-6 Mol…
2010
A method for the determination of dimethylamine in air by collection on solid support sorbent with subsequent derivatization and spectrophotometric a…
2005
A new method for dimethylamine determination in air is reported. The proposed assay is based on the employment of C18-packed solid phase extraction cartridges for sampling. The retained amine is then derivatized inside the cartridges with the reagent 1,2-naphthoquinone-4-sulfonate. By observing the coloured area of the cartridge, a semiquantitative estimation of the amine can be made. It was also possible to distinguish between primary and secondary amines by visual inspection. Quantitative tests entailed desorption from the cartridges of the derivatives formed, and measurement of the absorbance of the collected extracts. The selected conditions were applied to quantify dimethylamine up to …
Derivatization of amines in solid-phase extraction supports with 9-fluorenylmethyl chloroformate for liquid chromatography
1997
Abstract A new method based on reaction in solid-phase extraction cartridges with 9-fluorenylmethyl chloroformate is described for improved derivatization of amines prior to liquid chromatography. The effects of the reaction conditions, the kinetics of the reaction and the kind of packing material on the derivatization have been evaluated. The reliability of the described approach has been tested by derivatizing propylamine, diethylamine, diethanolamine, glycine, glutamic acid, p-aminobenzoic acid and β-phenylethylamine. Reaction yields compared with those of the analogous solution derivatizations were in the 44–169% range, and satisfactory linearity was achieved at concentrations of the am…
<title>Photoinduced anisotropy and holographic recording in amorphous chalcogenides</title>
2001
The effect of photoinduced anisotropy and its application to vector hologram recording is reviewed focusing on amorphous chalcogenides. Vector holographic grating recording in amorphous As-S-Se(a-As-S-Se) films is experimentally studied and analyzed in comparison with scalar recording. It is holographically established that a linearly polarized 632.8 nm light produces photoinduced anisotropy and the chalcogen related D+, D- center reorientation and generation mechanism is proposed. It is used to explain the observed peculiarities of vector recording in comparison with scalar recording based on photoinduced structural changes: much lower diffraction efficiency (4 X 10-3% versus 4%), much lar…
Snapshots of a solid-state transformation: Coexistence of three phases trapped in one crystal
2016
Crystal-to-crystal transformations have been crucial in the understanding of solid-state processes, since these may be studied in detail by means of single crystal X-ray diffraction (SCXRD) techniques. The description of the mechanisms and potential intermediates of those processes remains very challenging. In fact, solid-state transient states have rarely been observed, at least to a sufficient level of detail. We have investigated the process of guest extrusion from the non-porous molecular material [Fe(bpp)(HL)](ClO)·1.5CHO (bpp = 2,6-bis(pyrazol-3-yl)pyridine; HL = 2,6-bis(5-(2-methoxyphenyl)-pyrazol-3-yl)pyridine; CHO = acetone), which occurs through ordered diffusion of acetone in a c…
Growth temperature influence on the GaN nanowires grown by MOVPE technique
2011
GaN nanowires (NWs) were successfully grown by Vapor-Liquid-Solid (VLS) growth mechanism on GaN template using metal-organic vapor phase epitaxy (MOVPE) with diameters ranging from 20 to 200 nm and length up to few microns. The characterization by scanning electron microscopy (SEM) reveals an optimum growth temperature at 790°C and X-ray diffraction (XRD) investigations indicates oriented crystallinity of grown NWs.