762 research outputs found
Beyond scaling and locality in turbulence
An analytic perturbation theory is suggested in order to find finite-size
corrections to the scaling power laws. In the frame of this theory it is shown
that the first order finite-size correction to the scaling power laws has
following form , where
is a finite-size scale (in particular for turbulence, it can be the Kolmogorov
dissipation scale). Using data of laboratory experiments and numerical
simulations it is shown shown that a degenerate case with can
describe turbulence statistics in the near-dissipation range , where
the ordinary (power-law) scaling does not apply. For moderate Reynolds numbers
the degenerate scaling range covers almost the entire range of scales of
velocity structure functions (the log-corrections apply to finite Reynolds
number). Interplay between local and non-local regimes has been considered as a
possible hydrodynamic mechanism providing the basis for the degenerate scaling
of structure functions and extended self-similarity. These results have been
also expanded on passive scalar mixing in turbulence. Overlapping phenomenon
between local and non-local regimes and a relation between position of maximum
of the generalized energy input rate and the actual crossover scale between
these regimes are briefly discussed.Comment: extended versio
Non-specific cellular uptake of surface-functionalized quantum dots
We report a systematic empirical study of nanoparticle internalization into
cells via non-specific pathways. The nanoparticles were comprised of commercial
quantum dots (QDs) that were highly visible under a fluorescence confocal
microscope. Surface-modified QDs with basic biologically-significant moieties,
e.g. carboxyl, amino, streptavidin were used, in combination with the surface
derivatization with polyethylene glycol (PEG) in a range of immortalized cell
lines. Internalization rates were derived from image analysis and a detailed
discussion about the effect of nanoparticle size, charge and surface groups is
presented. We find that PEG-derivatization dramatically suppresses the
non-specific uptake while PEG-free carboxyl and amine functional groups promote
QD internalization. These uptake variations displayed a remarkable consistency
across different cell types. The reported results are important for experiments
concerned with cellular uptake of surface-functionalized nanomaterials, both
when non-specific internalization is undesirable and also when it is intended
for material to be internalized as efficiently as possible.
Published article at: http://iopscience.iop.org/0957-4484/21/28/285105/Comment: 14 pages 7 figure
Weak nuclear forces cause the strong nuclear force
We determine the strength of the weak nuclear force which holds the lattices
of the elementary particles together. We also determine the strength of the
strong nuclear force which emanates from the sides of the nuclear lattices. The
strong force is the sum of the unsaturated weak forces at the surface of the
nuclear lattices. The strong force is then about ten to the power of 6 times
stronger than the weak force between two lattice points.Comment: 12 pages, 1 figur
The use of conjugase preparations in the microbiological assay of folic acid
This article does not have an abstract
Plume motion and large-scale circulation in a cylindrical Rayleigh-B\'enard cell
We used the time correlation of shadowgraph images to determine the angle
of the horizontal component of the plume velocity above (below) the
center of the bottom (top) plate of a cylindrical Rayleigh-B\'enard cell of
aspect ratio ( is the diameter and mm
the height) in the Rayleigh-number range for a Prandtl number . We expect that gives the
direction of the large-scale circulation. It oscillates time-periodically. Near
the top and bottom plates has the same frequency but is
anti-correlated.Comment: 4 pages, 6 figure
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Method of varying template dimensions to achieve alignment during imprint lithography
A method of determining and correcting alignment during imprint lithography process is described. During an imprint lithographic process the template may be aligned with the substrate by the use of alignment marks disposed on both the template and substrate. The alignment may be determined and corrected for before the layer is processed.Board of Regents, University of Texas Syste
Comparative experimental study of local mixing of active and passive scalars in turbulent thermal convection
We investigate experimentally the statistical properties of active and
passive scalar fields in turbulent Rayleigh-B\'{e}nard convection in water, at
. Both the local concentration of fluorescence dye and the local
temperature are measured near the sidewall of a rectangular cell. It is found
that, although they are advected by the same turbulent flow, the two scalars
distribute differently. This difference is twofold, i.e. both the quantities
themselves and their small-scale increments have different distributions. Our
results show that there is a certain buoyant scale based on time domain, i.e.
the Bolgiano time scale , above which buoyancy effects are significant.
Above , temperature is active and is found to be more intermittent than
concentration, which is passive. This suggests that the active scalar possesses
a higher level of intermittency in turbulent thermal convection. It is further
found that the mixing of both scalar fields are isotropic for scales larger
than even though buoyancy acts on the fluid in the vertical direction.
Below , temperature is passive and is found to be more anisotropic than
concentration. But this higher degree of anisotropy is attributed to the higher
diffusivity of temperature over that of concentration. From the simultaneous
measurements of temperature and concentration, it is shown that two scalars
have similar autocorrelation functions and there is a strong and positive
correlation between them.Comment: 13 pages and 12 figure
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Method of determining alignment of a template and a substrate having a liquid disposed therebetween
The present invention includes a method of aligning a substrate and a template spaced-apart from the substrate with an activating light curable liquid disposed therebetween, the substrate having substrate alignment marks and the template having template alignment marks, the method including, reducing a distance between the substrate and the template to cause a spreading of the activating light curable liquid; and varying an overlay placement of the template with respect to the substrate such that the template alignment marks are substantially aligned with the substrate alignment marks before the spreading causes the activating light curable liquid to cover an area between the substrate alignment marks and the template alignment marks.Board of Regents, University of Texas Syste
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