530 research outputs found
Short-term power generation scheduling rules for cascade hydropower stations based on hybrid algorithm
AbstractPower generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm (POA) in combination with the genetic algorithm (GA). After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching
Bulk locality from the celestial amplitude
In this paper, we study the implications of bulk locality on the celestial
amplitude. In the context of the four-point amplitude, the fact that the bulk
S-matrix factorizes locally in poles of Mandelstam variables is reflected in
the imaginary part of the celestial amplitude. In particular, on the real axis
in the complex plane of the boost weight, the imaginary part of the celestial
amplitude can be given as a positive expansion on the Poincar\'e partial waves,
which are nothing but the projection of flat-space spinning polynomials onto
the celestial sphere. Furthermore, we derive the celestial dispersion relation,
which relates the imaginary part to the residue of the celestial amplitude for
negative even integer boost weight. The latter is precisely the projection of
low energy EFT coefficients onto the celestial sphere. We demonstrate these
properties explicitly on the open and closed string celestial amplitudes.
Finally, we give an explicit expansion of the Poincar\'e partial waves in terms
of 2D conformal partial waves.Comment: 43 pages, 10 figures. v2: typos corrected, minor clarifications
added, SciPost published versio
AT2022cmc: a Tidal Disruption Event with Two-component Jet in a Bondi-profile Circumnuclear Medium
A supermassive black hole can launch a relativistic jet when it violently
disrupts a star that passes too close. Such jetted tidal disruption events
(TDEs) are rare and unique tools to investigate quiescent supermassive black
holes, jet physics, and circumnuclear environment at high redshift. The newly
discovered TDE AT2022cmc () providing rich multi-band (X-ray, UV,
optical, sub-millimeter, and radio) data, has been interpreted as the fourth
on-axis jetted TDE. In this work, we constrain the circumnuclear medium (CNM)
density profile with both closure relation (CR) test and detailed forward shock
model fit with Markov chain Monte Carlo (MCMC) approach to the multi-band
(optical, sub-millimeter, and radio) data of AT2022cmc.We find that the CNM
density profile of AT2022cmc is with , implying
a Bondi accretion in history. Furthermore, our model fit result suggests a
two-component jet in AT2022cmc, indicating a similar jet physics to
well-studied jetted TDE Sw J1644+57.Comment: accepted in Ap
Recommended from our members
Water-Soluble Flexible Organic Frameworks That Include and Deliver Proteins.
Four water-soluble hydrazone-based three-dimensional (3D) flexible organic frameworks FOF-1-4 have been synthesized from a semirigid tetracationic tetraaldehyde and four flexible dihydrazides. 1H NMR spectroscopy indicated the quantitative formation of FOF-1-4 in D2O, while dynamic light scattering experiments revealed that, depending on the concentration, these porous frameworks display hydrodynamic diameters ranging from 50 to 120 nm. The porosity of the frameworks is confirmed by ethanol vapor adsorption experiments of the solid samples as well as the high loading capacity for a 2.3 nm porphyrin guest in water. The new water-soluble frameworks exhibit low cytotoxicity and form inherent pores with diameters of 5.3 or 6.7 nm, allowing rapid inclusion of proteins such as bovine serum albumin and green and orange fluorescent proteins, and efficient delivery of the proteins into normal and cancer cells. Flow cytometric analysis reveals percentages of the delivered cells up to 99.8%
Planets Across Space and Time (PAST) IV: The Occurrence and Architecture of Kepler Planetary Systems as a Function of Kinematic Age Revealed by the LAMOST-Gaia-Kepler Sample
One of the fundamental questions in astronomy is how planetary systems form
and evolve. Measuring the planetary occurrence and architecture as a function
of time directly addresses this question. In the fourth paper of the Planets
Across Space and Time (PAST) series, we investigate the occurrence and
architecture of Kepler planetary systems as a function of kinematic age by
using the LAMOST-Gaia-Kepler sample. To isolate the age effect, other stellar
properties (e.g., metallicity) have been controlled. We find the following
results. (1) The fraction of stars with Kepler-like planets ()
is about 50% for all stars; no significant trend is found between
and age. (2) The average planet multiplicity ()
exhibits a decreasing trend (~2 significance) with age. It decreases
from ~3 for stars younger than 1 Gyr to ~1.8 for stars
about 8 Gyr. (3) The number of planets per star
() also shows a decreasing trend
(~2-3 significance). It decreases from ~1.6-1.7 for young stars
to ~1.0 for old stars. (4) The mutual orbital inclination of the planets
() increases from to as
stars aging from 0.5 to 8 Gyr with a best fit of
.
Interestingly, the Solar System also fits such a trend. The nearly independence
of ~50% on age implies that planet formation is robust and
stable across the Galaxy history. The age dependence of and
demonstrates planetary architecture is evolving, and planetary
systems generally become dynamically hotter with fewer planets as they age.Comment: 27 pages, 20 figures, 4tables, accepted for publication in A
Planets Across Space and Time (PAST). III. Morphology of the Planetary Radius Valley as a Function of Stellar Age and Metallicity in the Galactic Context Revealed by the LAMOST-Gaia-Kepler Sample
The radius valley, a dip in the radius distribution of exoplanets at ~1.9
Earth radii separates compact rocky Super-Earths and Sub-Neptunes with lower
density. Various hypotheses have been put forward to explain the radius valley.
Characterizing the radius valley morphology and its correlation to stellar
properties will provide crucial observation constraints on its origin mechanism
and deepen the understanding of planet formation and evolution. In this paper,
the third part of the Planets Across the Space and Time (PAST) series, using
the LAMOST-Gaia-Kepler catalog, we perform a systematical investigation into
how the radius valley morphology varies in the Galactic context, i.e.,
thin/thick galactic disks, stellar age and metallicity abundance ([Fe/H] and
[alpha/Fe]). We find that (1) The valley becomes more prominent with the
increase of both age and [Fe/H]. (2) The number ratio of super-Earths to
sub-Neptunes monotonically increases with age but decreases with [Fe/H] and
[alpha/Fe]. (3) The average radius of planets above the valley (2.1-6 Earth
radii) decreases with age but increases with [Fe/H]. (4) In contrast, the
average radius of planets below the valley (R < 1.7 Earth radii) is broadly
independent on age and metallicity. Our results demonstrate that the valley
morphology as well as the whole planetary radius distribution evolves on a long
timescale of giga-years, and metallicities (not only Fe but also other metal
elements, e.g., Mg, Si, Ca, Ti) play important roles in planet formation and in
the long term planetary evolution.Comment: Accepted for pubilication in AJ, 20 Pages, 10 figures, 2 Tables
(Appendix: 13 Figures
Moral perfectionism and moral values, virtues, and judgments: A preliminary investigation
Moral perfectionism has a long tradition in philosophical inquiry, but so far has been ignored in psychological research. This article presents a first psychological investigation of moral perfectionism exploring its relationships with moral values, virtues, and judgments. In three studies, 539 university students responded to items of the Frost Multidimensional Perfectionism Scale (Frost, Marten, Lahart, & Rosenblate, 1990) adapted to measure personal moral standards (PMS) and concern over moral mistakes (CMM) and completed measures of moral values, virtues, and forgiveness, gratitude, and wrong behavior judgments. When partial correlations were computed controlling for the overlap between PMS and CMM, PMS showed positive correlations with moral values, virtues, reciprocal helping, forgiveness, and condemnation of wrong behaviors. In contrast, CMM showed a positive correlation only with indebtedness and a negative correlation with self-reliance. The present findings, while preliminary, suggest that moral perfectionism is a personality characteristic that may help explain individual differences in moral values, virtues, and judgments
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