769 research outputs found
Configurations, and parallelograms associated to centers of mass
The purpose of this article is to
\begin{enumerate}
\item define the -fold center of mass arrangement for points
in the plane,
\item give elementary properties of and
\item give consequences concerning the space of distinct points
in the plane, no four of which are the vertices of a parallelogram.
\end{enumerate}
The main result proven in this article is that the classical unordered
configuration of points in the plane is not a retract up to homotopy of the
space of unordered distinct points in the plane, no four of which are the
vertices of a parallelogram. The proof below is homotopy theoretic without an
explicit computation of the homology of these spaces.
In addition, a second, speculative part of this article arises from the
failure of these methods in the case of odd primes . This failure gives rise
to a candidate for the localization at odd primes of the double loop space
of an odd sphere obtained from the -fold center of mass arrangement.
Potential consequences are listed.Comment: 11 page
Convertible source system of thermal neutron and X-ray at Hokkaido University electron linac facility
The convertible source system for the neutron and the X-ray
imagings was installed in the 45MeV electron linear accelerator facility at Hokkaido University. The source system is very useful for a complementary imaging. The
imaging measurements for a sample were performed with both beams by using a vacuum tube type image intensifier. The enhanced contrast was obtained from the dataset of the radiograms measured with the neutron and X-ray beams
Recommended from our members
Molecular dynamics simulation of observed c(4x4) and c(4x3) C60 alignments on the Si(100) reconstructed surface.
We have implemented a large-scale classical molecular dynamics simulation at constant temperature to provide a theoretical insight into the results of a recently performed experiment on the monolayer and multi-layer formations of molecular films on the Si(100) reconstructed dimerized surface. Our simulation has successfully reproduced all of the morphologies observed on the monolayer film by this experiment. We have obtained the formation of both c(4 4) and c(4 3) structures of the molecules and have also obtained phase transitions of the former into the latter
Amelioration of normothermic canine liver ischemia with prostacyclin.
A model of hepatic ischemia was developed in dogs using a pump-driven splanchnic-to-jugular vein bypass during crossclamping of the portal triad. An LD50 was established with three hours of ischemia. PGI2 given for one hour before the ischemic insult ameliorated the ischemic injury and increased survival
Advances and Analysis on Reducing Webpage Response Time with Effect of Edge Computing
Modern webpages consist of many rich objects dynamically produced by servers and client terminals at diverse locations, so we face an increase in web response time. To reduce the time, edge computing, in which dynamic objects are generated and delivered from edge nodes, is effective. For ISPs and CDN providers, it is desirable to estimate the effect of reducing the web response time when introducing edge computing. Therefore, in this paper, we derive a simple formula that estimates the lower bound of the reduction of the response time by modeling flows obtaining objects of webpages. We investigate the effect of edge computing in each webpage category, e.g., News and Sports, using data measured by browsing about 1,000 popular webpages from 12 locations in the world on PlanetLab
Point defect dynamics in bcc metals
We present an analysis of the time evolution of self-interstitial atom and
vacancy (point defect) populations in pure bcc metals under constant
irradiation flux conditions. Mean-field rate equations are developed in
parallel to a kinetic Monte Carlo (kMC) model. When only considering the
elementary processes of defect production, defect migration, recombination and
absorption at sinks, the kMC model and rate equations are shown to be
equivalent and the time evolution of the point defect populations is analyzed
using simple scaling arguments. We show that the typically large mismatch of
the rates of interstitial and vacancy migration in bcc metals can lead to a
vacancy population that grows as the square root of time. The vacancy cluster
size distribution under both irreversible and reversible attachment can be
described by a simple exponential function. We also consider the effect of
highly mobile interstitial clusters and apply the model with parameters
appropriate for vanadium and iron.Comment: to appear in Phys. Rev.
A Mechanism of 13% Lattice Expansion in C_<60> FCC(110) Thin Films Grown on the GaAs(001) As-rich Surface
We perform a classical molecular dynamics simulation, a first-principle calculation based on LDA, and moreover a simple theoretical analysis to examine the very interesting crystalographic structure of the first layer and overlayer C_s adsorbed on the As-rich substrate of the GaAs(001) surface, which was recently observed with the STM by our group. From the classical molecular dynamics study, we reproduce the pairwise structure of C_ adsorbed in the first layer. On the other hand, from the first-principle study, we estimate how much the charge transfer is from the underlayer As atoms to the C_s adsorbed in the first layer. We found that the amount of this charge transfer is large enough to expect that the strong dipole field caused by this dipole layer at the interface induces dipole moments in the C_s adsorbed on overlayers and that the resulting dipole-dipole interaction among the overlayer C_ molecules is the origin of the 13% lattice expansion of the overlayer C_ fcc thin film observed experimentally
- …