6,960 research outputs found
Theory of Gelation: Post-Gelation Behavior
Within the framework of the random distribution assumption of cyclic bonds,
the preceding theory of gelation is extended to mixing systems with various
functionalities. To examine the validity of the assumption, the theory is
applied to experimental data in polyurethane network formation, the result
showing the soundness of the theory for the prediction of gel points and gel
fraction.Comment: 14 pages, 7 figure
Analogy and Difference between Gelation and Percolation Process
It has been verified that the theory of gelation with cyclization effects is
in good accord with experimental observations of gel points and gel fractions.
Encouraged by this success we scrutinize the prediction limit of the theory
through the rigor of the bond percolation theory. Significant disparity is
found between the prediction of the gelation theory and that of the percolation
theory. To find the reason of the disparity, we re-examine the distribution
function of bond animals; the analysis showing that the percolation process
differs from real gelations in two points: (i) whereas the real gelation obeys
the principle of equireactivity of functional units, the percolation process
does not; (ii) the substantial reduction of functionality occurs through the
percolation process. These make the lattice model intrinsically different from
real chemical processes. As a result, one can not make use of the percolation
theory for the purpose of examining the validity of the gelation theory.Comment: 10 pages, 2 figure
N=4 SYM on K3 and the AdS(3)/CFT(2) Correspondence
We study the Fareytail expansion of the topological partition function of N=4
SU(N) super Yang-Mills theory on K3. We argue that this expansion corresponds
to a sum over geometries in asymptotically AdS_3 spacetime, which is
holographically dual to a large number of coincident fundamental heterotic
strings.Comment: 10 pages; v5: typos correcte
Volume Expansion of Branched Polymers
The excluded volume effects of randomly branched polymers are investigated.
To approach this problem we assume the Gaussian distribution of segments around
the center of gravity. Once this approximation is introduced, we can make use
of the same method as employed for linear molecules. By simulating a
model-polymer system, it is found that the excluded volume effects of branched
polymers are manifested pronouncedly under any conditions from the dilution
limit to the melt, including the state; every result satisfies the
restraining condition: in accord with
our experiences. As a result the Gaussian approximation extracts the essential
features of the excluded volume effects of branched molecules.Comment: 14 pages, 6 figures, 1 table. arXiv admin note: substantial text
overlap with arXiv:1606.0392
Concentration Dependence of Excluded Volume Effects
The concentration dependence of the excluded volume effects in polymer
solutions is investigated. Through thermodynamic arguments for the
interpenetration of polymer segments and the free energy change, we show that
the disappearance of the excluded volume effects should occur at medium
concentration. The result is in accord with the recent experimental
observations.Comment: 12 pages, 6figures, 1 tabl
Coil Dimensions as a Function of Concentration
The preceding theory of excluded volume effects is applied to the Daud and
coworkers' observations. Based on various researchers' experimental data, it is
suggested that the Daud and coworkers' value in the bulk state may be revised
from 82 \AA to 93\AA. Then agreement between the theory and the revised data is
excellent, giving a support to the preceding result that the excluded volume
effects should vanish at medium concentration.Comment: 5 pages, 2 figures, 3 Table
N=4 SYM on R times S^3 and PP-Wave
We consider the radial quantization of N=4 super Yang-Mills (SYM) in 4
dimensions, i.e., N=4 SYM on a cylinder R times S^3. We construct the
generators of superconformal symmetry in the case of U(N) gauge group,
generalizing the earlier work by Nicolai et al. for U(1) gauge group. We study
how these generators contract to the symmetry of pp-wave when they act on a
state with large R-charge.Comment: 18 pages, lanlmac; v3: added a comment on Weyl anomal
Radius of Gyration of Randomly Branched Molecules
The mathematical derivation of the mean square radius of gyration, , of
branched polymers is reinvestigated from a kinetic-equation-point of view. In
particular we derive the corresponding quantity of the A-R-Bf-1 model; the
result showing that the mean square radius of gyration is precisely identical
with that of the R-Af model.Comment: 4 pages, 2 figure
Aging Concept in Population Dynamics
Author's early work on aging is developed to yield a relationship between
life spans and the velocity of aging. The mathematical analysis shows that the
mean extent of the advancement of aging throughout one's life is conserved, or
equivalently, the product of the mean life span, and the mean rate of aging is
constant. The result is in harmony with our experiences: It accounts for the
unlimited replicability of tumor cells, and predicts the prolonged life spans
of hibernating hamsters, in accordance with the Lyman and coworkers experiment.
Comparing the present result and the empirical relationship between life spans
of various mammals and basal metabolic rates, it is suggested that the mean
rate of aging is intimately connected with the mean basal metabolic rate. With
the help of this information, we inquire the reason of the difference in mean
life spans between women and men, the result showing that the relative mean
life span of women to men is 1 08, for various nations, which is close to the
corresponding relative value of the basal metabolic rate. The present theory
suggests, however, that this relationship between life spans and basal
metabolic rates must be treated with caution.Comment: 19 Pages, 7 Figure
1/2 BPS Correlator and Free Fermion
We propose that in the BMN limit the effective interaction vertex in the 1/2
BPS sector of N=4 SYM is given by the Das-Jevicki-Sakita Hamiltonian. We check
for some examples that it reproduces the 1/N correction to the correlation
functions of 1/2 BPS operators.Comment: 10 pages, 2 figures, lanlmac; v4: references adde
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