104 research outputs found
Calculation of light transmittance in a film: considerations of the coating geometry, the agent distribution, and its probability density distribution
Transmittance is an important parameter for various films such as sunscreen
films and creams, biofilms, coating materials, etc. Even if amounts of a
sunscreen agent are the same, the transmittance greatly changes depending on
the coating geometry (CG) and the agent distribution (AD) in the film. In this
study, we calculate the transmittance considering CG and AD. In addition, we
associate the transmittance with probability density distribution of the
thickness of the film. We found analytical and numerical solutions of the
transmittance in several model cases. It can be used for prediction of
performance of the sunscreen film and for a fair comparative evaluation.
Mathematical techniques in calculation of the transmittance are also explained
in detail
Theoretical study of solvent-mediated Ising-like system: A study for future nanotechnology
We theoretically study physical properties of one-dimensionally and regularly
placed solutes. The solute is rigid-body, has arrow-like shape, and changes its
direction up or down. If the solutes are immersed in continuum solvent, nothing
happens in the system. However, the property of the directions differs in
granular solvent (e.g., hard-sphere solvent). Depending on distance between the
nearest-neighbor solutes, the directional property periodically changes as
follows: "ferromagnetic-like" \leftrightarrow "random" \leftrightarrow
"antiferromagnetic-like". Furthermore, the directional property decays into
"random" as the distance increases. Studying a newly created nano-system
theoretically, it is able to discover a new or interesting property hiding in
nano-material world. We believe that such an approach gives physics research a
new direction and contributes to nanotechnology.Comment: Main Text (9 pages & 4 figures), Supplemental Material (4 pages & 1
figure
Measuring Method of a Surface Property inside the Pore: Application of Kelvin's equation
Surface analyses inside the nanopore, micropore, and a very narrow pipe are
important topics for development of the chemical engineering. Here, we propose
a measuring method which evaluates the surface coverage of the chemically
modified pore surface and the corrosion rate of the inner surface of the narrow
pipe, etc. The method uses Kelvin's equation that expresses saturated vapor
pressure of a liquid in the pore (pipe). The surface coverage and the corrosion
rate are calculated by measuring saturated vapor pressure of the liquid in the
pore and the pipe, respectively. In this letter, we explain the concept of the
method briefly.Comment: 4 pages, this is a short lette
Measurement theory of a density profile of colloid particles on a flat surface: Conversion of force acting on a colloidal probe into pressure on its surface element
Recently, we proposed a method that converts the force between two-large
colloids into the pressure on the surface element (FPSE conversion) in a system
of a colloidal solution. Using it, the density distribution of the small
colloids around the large colloid is calculated. In a similar manner, in this
letter, we propose a transform theory for colloidal probe atomic force
microscopy (colloidal probe AFM), which transforms the force acting on the
colloidal probe into the density distribution of the small colloids on a flat
surface. If measured condition is proper one, in our view, it is possible for
the transform theory to be applied for liquid AFM and obtain the liquid
structure. The transform theory we derived is briefly explained in this letter
An improved transform theory for estimation of number density distribution of colloidal particles on a surface: A method for colloidal-probe atomic force microscopy
In the short letter, we explain an improved transform theory for
colloidal-probe atomic force microscopy (CP-AFM). CP-AFM can measure a force
curve between the colloidal probe and a wall surface in a colloidal dispersion.
The transform theory can estimate the normalized number density distribution of
the colloidal particles on the wall from the force curve measured by CP-AFM.
The transform theory is important for study of the stratification of the
colloidal particles on the wall, which is related to fundamental studies of
colloidal crystal and glass
Measurement theory of a density profile of small colloids around a large colloid: Superposition of the radial distribution functions
We propose a transform theory for calculating a density profile of small
colloids around a large colloid from a force curve between the two-large
colloids. In the colloid solution, there are many small colloids and two or
several large colloids. The force curve between the two-large colloids can be
measured by laser tweezers. In this letter, the transform theory is derived in
detail, where a superposition approximation of the radial distributions of the
density profiles and rigid-body approximation are introduced. In our opinion,
if the experimental condition is satisfied, the transform theory can be used
not only for the laser tweezers, but also for surface force apparatus and
colloid probe atomic force microscopy. Furthermore, the transform theory is to
calculate a density profile of micelles around a large spherical surface
A method for calculating solvation structure on a sample surface from a force curve between a probe and the sample: One-dimensional version
Recent surface force apparatus (SFA) and atomic force microscopy (AFM) can
measure force curves between a probe and a sample surface in solvent. The force
curve is thought as the solvation structure in some articles, because its shape
is generally oscilltive and pitch of the oscillation is about the same as
diameter of the solvent. However, it is not the solvation structure. It is only
the force between the probe and the sample surface. Therefore, this brief paper
presents a method for calculating the solvation structure from the force curve.
The method is constructed by using integral equation theory, a statistical
mechanics of liquid (Ornstein-Zernike equation coupled by hypernetted-chain
closure). This method is considered to be important for elucidation of the
solvation structure on a sample surface.Comment: Solvation Structure, Hydration Structure, SFA, AFM, Integral Equation
Theor
Measurement theory of a density profile of small spheres on a cylindrical surface: Conversion of force curve measured with surface force apparatus into pressure on its surface element
Recently, in an ensemble of small spheres, we proposed a method that converts
the force between two large spheres into the pressure on the large sphere's
surface element. Using it, the density distribution of the small spheres around
the large sphere can be obtained experimentally. In a similar manner, in this
letter, we propose a transform theory for surface force apparatus, which
transforms the force acting on the cylinder into the density distribution of
the small spheres on the cylindrical surface. The transform theory we derived
is briefly explained in this letter.Comment: 3 figure
A method of comparison between a force curve measured on a solvated surface and the solvation structure
Recent atomic force microscopy (AFM) can measure force curves between a probe
and a sample surface in solvent. The force curve is thought as the solvation
structure in some cases, because its shape is generally oscilltive and pitch of
the oscillation is about the same as diameter of the solvent. However, it is
not the solvation structure. It is just only a mean force between the probe and
the sample surface. A theoretical relation between the mean force and the
solvation structure is not clearly known. Therefore, the relation must be
elucidated theoretically to deepen understanding of the mean force measured by
the AFM. In this letter, we briefly explain the relation and a method for
comparing the measured mean force and the solvation structure (that obtained by
a simulation, a liquid theory, or a x-ray reflectivity) by using basic
statistical mechanics of liquid
Relation between a force curve measured on a solvated surface and the solvation structure: Relational expressions for a binary solvent and a molecular liquid
Recent atomic force microscopy (AFM) can measure force curves between a probe
and a sample surface in several solvents. The force curve is thought as the
solvation structure in some cases, because its shape is generally oscilltive
and pitch of the oscillation is about the same as diameter of the solvent.
However, it is not the solvation structure. It is just only a mean force
between the probe and sample surface. Since theoretical relation between the
mean force and the solvation structure had not been clearly known, we have
recently derived a relational expression within a simple liquid. Although we
have derived the relational expression within the simple liquid, the relational
expressions for a binary solvent and a molecular liquid have still not known
clearly. Hence, we try to obtain the relational expressions in the two types of
the solvents. In this letter, we briefly derive the relations and explain a
method for comparing the mean force measured by liquid AFM and the solvation
structure (obtained by a simulation, a liquid theory, or a x-ray reflectivity).
The derivations of the relational expressions are performed in the basis of
classical statistical mechanics of liquid
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