Search results for "force"
showing 10 items of 3423 documents
Computer-Controlled Experiments in the Surface Forces Apparatus with a CCD-Spectrograph
1996
We present a computer-controlled technique to measure the distance-dependent forces in the surface forces apparatus. The power of our setup is shown by a measurement of the repulsive forces between mica surfaces immersed in a 0.01 M NaCl solution. At close distances we find an oscillatory force with a periodicity of 0.30 nm, which roughly corresponds to the diameter of a water molecule. For the distance determination we use the standard interferometric technique: the interferometer consists of a medium sandwiched between two mica sheets of equal thickness silvered on the backside. The surface separation is measured by comparing the resonance wavelength to the one obtained from contacting m…
Dispersive interactions between atoms and nonplanar surfaces
2009
We calculate the dispersive force between a ground state atom and a non planar surface. We present explicit results for a corrugated surface, derived from the scattering approach at first order in the corrugation amplitude. A variety of analytical results are derived in different limiting cases, including the van der Waals and Casimir-Polder regimes. We compute numerically the exact first-order dispersive potential for arbitrary separation distances and corrugation wavelengths, for a Rubidium atom on top of a silicon or gold corrugated surface. We discuss in detail the inadequacy of the proximity force approximation, and present a simple but adequate approximation for computing the potentia…
Supersaturation and Crystal Nucleation in Confined Geometries
1998
Surface aggregation as a necessary condition for interfacially induced crystal nucleation is studied with a surface forces apparatus (SFA).1-3 As a model system, we use the chloride salt of the rod...
Surface topography of membrane domains
2010
金沢大学理工研究域数物科学系
Light source inner surface changes depending on treatment
2008
Our work is connected with the preparation of different type of electrodeless discharge lamps. In this work we investigate the influence of the SiO2 glass wall treatment procedures on the inner surface of the electrodeless lamps. Three different treatment procedures were applied: vacuum cleaning, vacuum-thermal cleaning and training in the high frequency discharge. The surface modification has been investigated by means of atomic force microscopy. Substantial changes of the SiO2 glass surface have been observed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation on the influence of the surface resin rich layer on the thermoelastic signal from different composite laminate lay-ups
2006
This work presents a set of experimental results based on the measured thermoelastic signal from GRP composite coupons adopting different lay-ups. A comparison is made with the thermoelastic signal predicted by two different analytical models: one based on the classical law of the thermoelastic effect for orthotropic materials, and the other based on a novel theory accounting for the presence of a resin layer on the external surface of the composite structure. The composite coupons were designed such to determine a significant difference in the predictions made by the two theoretical models. Experimental results have shown a far better match with the predictions based on the novel theory ac…
The dielectric α -relaxation in polymer films: A comparison between experiments and atomistic simulations
2013
The question of whether the glass transition temperature in thin polymer films depends on the film thickness or not has given rise to heated debate for almost two decades now. One of the most puzzling findings is the seemingly universal thickness independence of the dielectric α-relaxation observed for supported films. It is puzzling not only in view of the fact that other techniques or other geometries sometimes showed a significant shift of as a function of film thickness, but more so, because computer simulations for all types of polymer film models revealed changes in the structure and dynamics close to a hard surface or a free surface. Our results suggest to explain this apparent contr…
A Slightly Modified Expression of the Polar Surface Area Applied to an Olfactory Study
2013
The polar surface area of a molecule is currently defined as the surface sum over all polar atoms, primarily oxygen and nitrogen, also including their attached hydrogens (named PSA1 in the present study). Some authors also include sulfur and phosphor (PSA3). The slight modification suggested here is based on the fact that it is difficult to consider, on a theoretical point of view, hexavalent S and pentavalents N and P as polar atoms. Indeed, in these cases, all their peripheral electrons are involved in bondings. We propose to define PSA2 using the initial definition extended to O, S, N, P, with the exception of hexavalent S and pentavalents N and P. In order to test this hypothesis, the t…
Printing Life-Inspired Subcellular Scale Compartments with Autonomous Molecularly Crowded Confinement.
2019
A simple, rapid, and highly controlled platform to prepare life-inspired subcellular scale compartments by inkjet printing has been developed. These compartments consist of fL-scale aqueous droplets (few µm in diameter) incorporating biologically relevant molecular entities with programmed composition and concentration. These droplets are ink-jetted in nL mineral oil drop arrays allowing for lab-on-chip studies by fluorescence microscopy and fluorescence life time imaging. Once formed, fL-droplets are stable for several hours, thus giving the possibility of readily analyze molecular reactions and their kinetics and to verify molecular behavior and intermolecular interactions. Here, this pla…
Competition between surface reaction and diffusion of gold deposited onto ZrTe3
2003
Abstract Surface reaction and diffusion of gold, deposited onto the (0 0 1) ZrTe 3 van der Waals (vdW) surface, is studied by transmission electron and scanning tunneling microscopy. It is shown that both processes compete at temperatures as low as room temperature. In case of diffusion the deposited gold mostly disappears from the surface and intercalates into the vdW gaps of the substrate. Residual unreacted gold agglomerates are rather mobile and are often displaced by the scanning tip along the [1 0 0] direction of the substrate. In case of reaction, which usually takes place at somewhat higher substrate temperatures, grains of Zr 3 Te 2 , AuTe 2 and/or Au 2 Te 3 are formed. Contrary to…