Search results for "Metre"
showing 10 items of 150 documents
Towards micrometer sized core-shell actuators from liquid crystalline elastomers by a continuous flow synthesis
2012
We present here the successful preparation of liquid crystalline core-shell elastomers via a microfluidic double-emulsion process. The customized set-up allows for a temperature-controlled fabrication of the core-shell particles from a thermoresponsive mesogenic monomer. The nematic liquid crystalline shell is filled with a non-mesogenic core of silicone oil. To verify the core-shell structure with optical microscopy, we prepared particles with a colored core using a red dye. We were also able to micro-manipulate the particles and penetrate them with a small glass capillary to extract the liquid core.
Domain Structures in Langmuir-Blodgett Films Investigated by Atomic Force Microscopy
1993
Investigations of phase-separated Langmuir-Blodgett films by atomic force microscopy reveal that on a scale of 30 to 200 micrometers, these images resemble those observed by fluorescence microscopy. Fine structures (less than 1 micrometer) within the stearic acid domains were observed, which cannot be seen by conventional optical microscopic techniques. By applying the force modulation technique, it was found that the elastic properties of the domains in the liquid condensed phase and grains observed within the liquid expanded phase were comparable. Small soft residues in the domains could also be detected. The influence of trace amounts of a fluorescence dye on the micromorphology of monol…
Measurement of sulfur isotope ratios in micrometer-sized samples by NanoSIMS
2006
Abstract Sulfur isotope ratios of atmospheric aerosol particles can provide detailed information with regard to the origin and the transport of sulfur in the environment. The new Cameca NanoSIMS 50 ion microprobe technique permits analysis of individual aerosol particles with volumes down to 0.5 μm 3 and a precision for δ 34 S of 3–10‰ (2 σ ). This technique will set new standards in the analysis of isotope ratios in atmospheric aerosol. For the first time it is possible to directly compare chemical and isotopic composition of individual aerosol particles, identify internal and external mixtures and investigate reactions of anthropogenic gases with natural aerosol such as sea salt and miner…
Influence of pH and temperature on the early stage of mica alteration
2012
Mineral dissolution and precipitation reactions actively participate in controlling fluid chemistry during water–rock interaction. In this study, the changes in the biotite and muscovite basal surface nano-morphology were evaluated during interaction with fluids of different pH (pH = 1.1, 3.3 and 5.7) at different temperatures (T =2 5, 120, and 200 C). Results show that at the nanometre scale resolution of the atomic force microscope (AFM), dissolution generates etch pits with a stair-shaped pattern over the (0 0 1) surface. The flux of dissolved elements decreases when pH increases. However, at pH 5.7, a change was found in the flux after 42 h of reaction when abundant gibbsite and kaolini…
The gold-sulfur interface at the nanoscale.
2012
Thiolate-protected gold surfaces and interfaces, relevant for self-assembled monolayers of organic molecules on gold, for passivated gold nanoclusters and for molecule-gold junctions, are archetypal systems in various fields of current nanoscience research, materials science, inorganic chemistry and surface science. Understanding this interface at the nanometre scale is essential for a wide range of potential applications for site-specific bioconjugate labelling and sensing, drug delivery and medical therapy, functionalization of gold surfaces for sensing, molecular recognition and molecular electronics, and gold nanoparticle catalysis. During the past five years, considerable experimental …
Determining the Geometry of Hydrogen Bonds in Solids with Picometer Accuracy by Quantum-Chemical Calculations and NMR Spectroscopy
2005
The structure of multiply hydrogen-bonded systems is determined with picometer accuracy by a combined solid-state NMR and quantum-chemical approach. On the experimental side, advanced 1H-15N dipolar recoupling NMR techniques are capable of providing proton-nitrogen distances of up to about 250 pm with an accuracy level of +/-1 pm for short distances (i.e., around 100 pm) and +/-5 pm for longer ones (i.e., 180 to 250 pm). The experiments were performed under fast magic-angle spinning, which ensures sufficient dipolar decoupling and spectral resolution of the 1H resonance lines. On the quantum-chemical side, the structures of the hydrogen-bonded systems were computationally optimised, yieldin…
Characterizing Low-Permeable Granitic Rock from Micrometer to Centimeter Scale: X-ray Microcomputed Tomography, Confocal Laser Scanning Microscopy an…
2006
AbstractFirst results of combining X-ray microcomputer tomography (µCT), confocal laser-scanning microscopy (CLSM) and 14C-polymethylmethacrylate (14C-PMMA) impregnation techniques in the study of granitic rock samples are reported. Combining results of µCT and CLSM with those of the 14C-PMMA technique, the mineral-specific porosity and morphology of the open pore space, as well as its connectivity, could be analyzed from a micrometer up to a decimeter scale.Three different types of granite were studied. In two cases part of the micro-fissure and pore apertures were found to be in a micrometer scale, but in one case all grain-boundary openings were below the detection limit. Micrometer-scal…
Electron microscopy of gold nanoparticles at atomic resolution
2014
Detailed structure of a gold nanoparticle Adding only a few atoms or changing the capping ligand can dramatically change the structure of individual metal nanoparticles. Azubel et al. used aberration-corrected transmission electron microscopy to derive a three-dimensional reconstruction of water-soluble gold nanoparticles. Small-angle x-ray scattering and other techniques have also corroborated this model. They used this to determine the atomic structure, which compared favorably with density functional theory calculations, without assuming any a priori structural knowledge or the use of model fitting. Science , this issue p. 909
The development of rhythm at the age of 6–11 years: non-pitch rhythmic improvisation
2006
In the statistical and transcriptional analyses reported in this exploratory study, original rhythms of 6–11-year-old children (N = 36) were examined. The hypotheses were based on a new model of musical development, and tested empirically using non-pitch rhythmic improvisation in a MIDI-environment. Several representational types were found in cluster analysis. The types are comparable to those found in earlier studies of rhythm. A dimensional conflict appeared between grouping and metre, and was solved in the last substage (10–11 years). Age was found to be a significant factor in the development of the hierarchy of form, the amount of different rhythm patterns, the metrical hierarchy, as …
Nanoscale Deposition of Single-Molecule Magnets onto SiO2 Patterns
2007
bet on a silicon oxide template while the rest ofthe macroscopic surface remains free of molecules. Local oxi-dation was used to fabricate silicon oxide nanopatterns, eitherdots or stripes, over a Si (100) surface coated with a SAM.Their width ranged from 30 to 500 nm whereas the lengthcould be modified from a few nanometers up to several mi-crometers. Nanoscale direct assembly arose from a combina-tion of three factors: i) the strength of the attractive electro-static interactions between the molecules and the local oxides;ii) the weak repulsive interaction between the molecules andthe unpatternedsurface; and iii) the size of the nanopattern.Local oxidation nanolithography (LON) allows the…