15,494 research outputs found
Properties of Microlensing Central Perturbations by Planets in Binary Stellar Systems under the Strong Finite-Source Effect
We investigate high-magnification events caused by planets in wide binary
stellar systems under the strong finite-source effect, where the planet orbits
one of the companions. From this, we find that the pattern of central
perturbations in triple lens systems commonly appears as a combination of
individual characteristic patterns of planetary and binary lens systems in a
certain range where the sizes of the caustics induced by a planet and a binary
companion are comparable, and the range changes with the mass ratio of the
planet to the planet-hosting star. Specially, we find that because of this
central perturbation pattern, the characteristic feature of high-magnification
events caused by the triple lens systems appears in the residual from the
single-lensing light curve despite the strong finite-source effect, and it is
discriminated from those of the planetary and binary lensing events and thus
can be used for the identification of the existence of both planet and binary
companion. This characteristic feature is a simultaneous appearance of two
features. First, double negative-spike and single positive-spike features
caused by the binary companion appear together in the residual, where the
double negative spike occurs at both moments when the source enters and exits
the caustic center and the single positive spike occurs at the moment just
before the source enters into or just after the source exits from the caustic
center. Second, the magnification excess before or after the single
positive-spike feature is positive due to the planet, and the positive excess
has a remarkable increasing or decreasing pattern depending on the source
trajectory.Comment: 12 pages, 3 figures, accepted for publication in Ap
Non-thermal radiation of black hole off canonical typicality
We study the Hawking radiation of black holes by considering the canonical
typicality. For the universe consisting of black holes and their outer part, we
directly obtain a non-thermal radiation spectrum of an arbitrary black hole
from its entropy, which only depends on a few external qualities (known as
hairs), such as mass, charge, and angular momentum. Our result shows that the
spectrum of the non-thermal radiation is independent of the detailed quantum
tunneling dynamics across black hole horizon. We prove that the black hole
information paradox is naturally resolved by taking account the correlation
between black hole and its radiation in our approach.Comment: 5 pages, 1 figure, pulished on Europhysics Letters, comments are
welcome
Managing Distrust-Induced Risk with Deposit in Supply Chain Contract Decisions
This paper studies the trust issue in a two-echelon supply chain information sharing process. In a supply chain, the retailer reports the forecasted demand to the supplier. Traditionally, the supplier’s trust in the retailer’s reported information is based on the retailer’s reputation. However, this paper considers that trust is random and is also affected by the reputation and the demand gap. The supplier and retailer have been shown to have different evaluations regarding the degree of trust. Furthermore, distrust is inherently linked to perceived risk. To mitigate perceived risk, a two-stage decision process with an unpayback deposit contract is proposed. At the first stage, the supplier and the retailer negotiate the deposit contract. At the second stage, a Stackelberg game is used to determine the retailer’s reported demand and the supplier’s production quantity. We show that the deposits from the retailer’s and supplier’s perspectives are different. When the retailer’s reported demand is equal to the supplier’s forecasted demand, the retailer’s evaluation of the deposit is more than that of supplier’s. When the retailer’s reported demand is equal to the retailer’s forecasted demand, the deposit from the retailer’s perspective is at the lowest level
Properties of the Planetary Caustic Perturbation
Just two of 10 extrasolar planets found by microlensing have been detected by
the planetary caustic despite the higher probability of planet detection
relative to the central caustic which has been responsible for four extrasolar
planet detections. This is because the perturbations induced by the planetary
caustic are unpredictable, thus making it difficult to carry out strategic
observations. However, if future high-cadence monitoring surveys are conducted,
the majority of planetary caustic events including the events by free-floating
planets and wide-separation planets would be detected. Hence, understanding the
planetary caustic perturbations becomes important. In this paper, we
investigate in detail the pattern of the planetary caustic perturbations. From
this study, we find three properties of the planetary caustic perturbations.
First, planetary systems with the same star-planet separation (s) basically
produce perturbations of constant strength regardless of the planet/star mass
ratio (q), but the duration of each perturbation scales with sqrt{q}. Second,
close planetary systems with the same separation produce essentially the same
negative perturbations between two triangular-shaped caustics regardless of q,
but the duration of the perturbations scales with sqrt{q}. Third, the positive
perturbations for planetary systems with the same mass ratio become stronger as
the caustic shrinks with the increasing |log s|, while the negative
perturbations become weaker. We estimate the degeneracy in the determination of
q that occurs in planetary caustic events. From this, we find that the mass
ratio can be more precisely determined as q increases and |log s| decreases. We
also find that the degeneracy range of events for which the source star passes
close to the planetary caustic is usually very narrow, and thus it would not
significantly affect the determination of q.Comment: 5 pages, 3 figures, 2 tables, accepted in MNRA
Self-consistency of optimizing finite-time Carnot engines with the low-dissipation model
The efficiency at the maximum power (EMP) for finite-time Carnot engines
established with the low-dissipation model, relies significantly on the
assumption of the inverse proportion scaling of the irreversible entropy
generation on the operation time , i.e.,
. The optimal operation time of the
finite-time isothermal process for EMP has to be within the valid regime of the
inverse proportion scaling. Yet, such consistency was not tested due to the
unknown coefficient of the -scaling. In this paper, using a two-level
atomic heat engine as an illustration, we reveal that the optimization of the
finite-time Carnot engines with the low-dissipation model is self-consistent
only in the regime of , where is the
Carnot efficiency. In the large- regime, the operation time
for EMP obtained with the low-dissipation model is not within the valid regime
of the -scaling, and the exact EMP is found to surpass the well-known
bound Comment: 6 pages, 4 figures, Comments are welcom
Hysteresis behavior of reinforced concrete bridge piers considering strength and stiffness degradation and pinching effect
In order to effectively simulate the nonlinear hysteresis behavior of reinforced concrete (RC) bridge piers under strong earthquake excitation, an improved nonlinear hysteresis model for RC bridge piers was developed and its controlling parameters were determined considering stiffness and strength degradation and pinching effect based on classical Bouc-Wen model. The improved model can be carried out to predict the nonlinear hysteresis behavior of RC bridge piers under various failure modes using MATLAB/ Simulink program. Cyclic tests of different failure mode bridge column specimens were performed under constant axial load with lateral bending. The results did show that force-displacement relationship curves of bridge column specimens derived from theoretical analysis agree well with experimental results. The nonlinear hysteresis behavior of bridge column specimen was simulated under 2008 Wenchuan earthquake excitation and its failure modes were identical with real earthquake damage of bridge column. The improved analytical models in the paper were applied to accurately predicting the nonlinear hysteresis behavior of RC bridge columns with strength and stiffness degradations and the pinching effect subjected to strong earthquake motion
- …