4,011 research outputs found
Theory of photoinduced charge transfer in weakly coupled donor-acceptor conjugated polymers: application to an MEH-PPV:CN-PPV pair
In a pair of coupled donor-acceptor conjugated polymer chains, it is possible
for an exciton photoexcited on either polymer to decay into a hole in the donor
polymer's valence band and an electron in the conduction band of the acceptor
polymer. We calculate the corresponding exciton decay rate and its dependence
on inter-polymer distance. For a pair of derivatives of poly(phenylene
vinylene), PPV, specifically poly[2-methoxy, 5-(2-ethyl-hexyloxy)-1, 4
PPV], MEH-PPV, and poly(2,5-hexyloxy -phenylene cyanovinylene), CN-PPV, at a
separation of 6 \AA the characteristic decay time is 2.2 ps, whereas at 4 \AA
it is fs.Comment: 9 pages, RevTeX, 4 PS files, to be published in a special issue of
Chem. Phy
Measurements of the ion concentrations and conductivity over the Arabian Sea during the ARMEX
Measurements of the small-, intermediate-, and large-ion concentrations and
the atmospheric electric conductivity of both polarities have been made over
the Arabian Sea on four cruises of ORV Sagarkanya during the Arabian Sea
Monsoon Experiment (ARMEX)during the monsoon and pre-monsoon seasons of 2002
and 2003. Seasonally averaged values of the total as well as polar conductivity
are much higher during the monsoon than pre-monsoon season. Surprisingly,
however, the concentration of small ions are less and those of large and
intermediate ions are more during the monsoon than pre-monsoon season. The
diurnal variations observed during the pre-monsoon season show that the
nighttime small ion concentrations are about an order of magnitude higher than
their daytime values. On the contrary, the daytime concentrations of the
intermediate and large ions are much higher than those of their nighttime
values. No such diurnal variations in ion concentrations are observed in
monsoon season. Also examined are the variations in ion concentrations of
different categories with distance from the coastline in different seasons and
the ion-concentration changes associated with the precipitation of various
types that occurred over ORV Sagarkanya. It is sufficient to invoke the
ion-aerosol attachment process to explain our pre-monsoon observations.
However, the generation of highly charged large ions by the bubble-breaking
process caused by the wave breaking due to strong southwesterly surface winds
ten to twenty meter per second over the Arabian Sea is postulated to explain
the monsoon season observations.Comment: 35 pages, 8 figure
Identifying Types of Staying Facilities from Traffic Behavior Log Data
AbstractTraffic behavior surveys by hand require both a lot of money and human resources. Recently, traffic behavior surveys using information technology have been carried out. In this study, we propose a method to extract staying points from GPS-based positional data and identify the types of staying facilities by using Google Places API, a facility ontology, the regularity which is analyzed from trip chains about traffic behavior. This method could identify 68.5% types of staying facilities correctly in the evaluation using GPS location data from the Traffic Behavior Survey in Nagasaki
Quantum tunneling in ^{277}112 and its alpha-decay chain
The -decay half lives of nuclei in the decay from element
are calculated in a WKB framework using DDM3Y interaction and experimental
Q-values. Theoretical estimation of half lives in the same quantum tunneling
model, using Q-values from the mass formula of
Muntian-Hofmann-Patyk-Sobiczewski, are also presented. Calculated results
furnish corroborating evidence for the experimental findings at RIKEN and GSI.
Certain discrepancies indicate necessity of a better mass formula. Further
experimental data with higher statistics would also be useful.Comment: 10 page
vertex from QCD sum rules
The form factors and the coupling constants in the
vertex are evaluated in the framework of three-point QCD sum rules. The
correlation functions responsible for the form factors are evaluated
considering contributions of both and mesons as off-shell
states. The obtained numerical results for the coupling constants are in
agreement with light-cone QCD sum rules calculations.Comment: 18 pages, 11 figures, to appear on Phys. Lett.
Cost-effectiveness Analysis of CO2 Reduction in the Automobile Sector
Various problems relating to energy and the environment clearly exist, such as global warming and a steep rise in the price fossil fuels, and resources. These problems should be addressed in the medium term or long run. As for the abatement of greenhouse gas emission, active discussions have been held on the stage of world politics to achieve the long-term goal. Although various approaches have been proposed by several research institutions and countries, sufficient studies have not yet been conducted on the roles of individual countries and sectors. Specifically, in the automotive transportation sector wherein oil demand and CO2 emissions are estimated to rise in the future with the marked progress of motorization in developing countries, it is increasingly important to study these subjects. We focused on the automotive transportation sector and studied the CO2 abatement potential and its cost performance in this sector. This article reports the results of the study.energy and the environment, Climate change, automotive transportation
Effects of Propofol on Left Ventricular Mechanoenergetics in the Excised Cross-circulated Canine Heart
Although propofol is commonly used for general anesthesia, its direct effects on left ventricular (LV) contractility and energetics remain unknown. Accordingly, we studied the effects of intracoronary propofol on excised cross-circulated canine hearts using the framework of the Emax (a contractility index)-PVA (systolic pressure-volume area, a measure of total mechanical energy)-Vo2 (myocardial oxygen consumption per beat) relationship. We obtained 1) the Vo2-PVA relationship of isovolumic contractions with varied LV volumes at a constant Emax, 2) the Vo2-PVA relationship with varied LV volumes at a constant intracoronary concentration of propofol, and 3) the Vo2-PVA relationship under increased intracoronary concentrations of either propofol or CaCl2 at a constant LV volume to assess the cardiac mechanoenergetic effects of propofol. We found that propofol decreased Emax dose-dependently. The slope of the linear Vo2-PVA relationship (oxygen cost of PVA) remained unchanged by propofol. The PVA-independent Vo2-Emax relationship (oxygen cost of Emax) was the same for propofol and Ca2+. In conclusion, propofol showed a direct negative inotropic effect on LV. At its clinical concentrations, decreases in contractility by propofol were relatively small. Propofol shows mechanoenergetic effects on the LV that are similar to those of Ca2+ blockers or ß-antagonists—i.e., it exerts negative inotropic effects without changing the oxygen costs of Emax and PVA
Inter-Intra Molecular Dynamics as an Iterated Function System
The dynamics of units (molecules) with slowly relaxing internal states is
studied as an iterated function system (IFS) for the situation common in e.g.
biological systems where these units are subjected to frequent collisional
interactions. It is found that an increase in the collision frequency leads to
successive discrete states that can be analyzed as partial steps to form a
Cantor set. By considering the interactions among the units, a self-consistent
IFS is derived, which leads to the formation and stabilization of multiple such
discrete states. The relevance of the results to dynamical multiple states in
biomolecules in crowded conditions is discussed.Comment: 7 pages, 7 figures. submitted to Europhysics Letter
Future of superheavy element research: Which nuclei could be synthesized within the next few years?
Low values of the fusion cross sections and very short half-lives of nuclei
with Z120 put obstacles in synthesis of new elements. Different nuclear
reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and
neutron capture), which could be used for the production of new isotopes of
superheavy (SH) elements, are discussed in the paper. The gap of unknown SH
nuclei, located between the isotopes which were produced earlier in the cold
and hot fusion reactions, can be filled in fusion reactions of Ca with
available lighter isotopes of Pu, Am, and Cm. Cross sections for the production
of these nuclei are predicted to be rather large, and the corresponding
experiments can be easily performed at existing facilities. For the first time,
a narrow pathway is found to the middle of the island of stability owing to
possible -decay of SH isotopes which can be formed in ordinary fusion
reactions of stable nuclei. Multi-nucleon transfer processes at near barrier
collisions of heavy (and very heavy, U-like) ions are shown to be quite
realistic reaction mechanism allowing us to produce new neutron enriched heavy
nuclei located in the unexplored upper part of the nuclear map. Neutron capture
reactions can be also used for the production of the long-living neutron rich
SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors
and by nuclear explosions in laboratory conditions and by supernova explosions
in nature. All these possibilities are discussed in the paper.Comment: An Invited Plenary Talk given by Valeriy I. Zagrebaev at the 11th
International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio,
Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in
Journal of Physics: Conference Series (JPCS
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