1,651 research outputs found
An improved method to determine the mixing
We develop an improved method to explore the mixing which
arises from the flavor SU(3) and heavy quark symmetry breaking. In this method,
the flavor eigenstates under the SU(3) symmetry are at first constructed and
the corresponding masses can be nonperturbatively determined. Matrix elements
of the mass operators which break the flavor SU(3) symmetry sandwiched by the
flavor eigenstates are then calculated. Diagonalizing the corresponding matrix
of Hamiltonian gives the mass eigenstates of the full Hamiltonian and
determines the mixing. Following the previous lattice QCD calculation of
and , and estimating an off-diagonal matrix element, we extract
the mixing angle between the and . Preliminary numerical
results for the mixing angle confirm the previous observation that such mixing
is incapable to explain the large SU(3) symmetry breaking in semileptonic
decays of charmed baryons.Comment: 7 pages, 3 figure
Cavity-Heisenberg spin chain quantum battery
We propose a cavity-Heisenberg spin chain (CHS) quantum battery (QB) with the
long-range interactions and investigate its charging process. The performance
of the CHS QB is substantially improved compared to the Heisenberg spin chain
(HS) QB. When the number of spins , the quantum advantage of
the QB's maximum charging power can be obtained, which approximately satisfies
a superlinear scaling relation . For the CHS QB,
can reach and even exceed , while the HS QB can only reach about
. We find that the maximum stored energy of the CHS QB has a
critical phenomenon. By analyzing the Wigner function, von Neumann entropy, and
logarithmic negativity, we demonstrate that entanglement can be a necessary
ingredient for QB to store more energy, but not sufficient
A system dynamics model for urban taxi price simulation
Urban taxi services have been developing year on year, playing an increasingly important role in the economy and the transportation markets of each city. This increases interest in measuring their performance. This paper analysed the relationship among the four stakeholders (including administrative department, operational companies, taxi drivers and customers) for urban taxi passenger transport system in China, and applied System Dynamics (SD) model to explore the dynamic characteristics of urban taxi price system. The main achievements of this paper are as follows, firstly, this paper adopted stakeholder mapping to describe the relationships among the four stakeholders. Then analysed the causal flow diagrams and the different variables of urban taxi passenger transport system operation, and presented the SD model, which considers factors that affect the taxi operation. With the combination of taxi operation data of Harbin city, we simulated eleven urban taxi operation scenarios and proposed kinds of suggestions to improve urban taxi passenger transport system operation, which can provide a good basis for recommending policy decisions for urban taxi market
Detecting Exploit Primitives Automatically for Heap Vulnerabilities on Binary Programs
Automated Exploit Generation (AEG) is a well-known difficult task, especially
for heap vulnerabilities. Previous works first detected heap vulnerabilities
and then searched for exploitable states by using symbolic execution and
fuzzing techniques on binary programs. However, it is not always easy to
discovery bugs using fuzzing or symbolic technologies and solvable for internal
overflow of heap objects. In this paper, we present a solution DEPA to detect
exploit primitives based on primitive-crucial-behavior model for heap
vulnerabilities. The core of DEPA contains two novel techniques, 1)
primitive-crucial-behavior identification through pointer dependence analysis,
and 2) exploit primitive determination method which includes triggering both
vulnerabilities and exploit primitives. We evaluate DEPA on eleven real-world
CTF(capture the flag) programs with heap vulnerabilities and DEPA can discovery
arbitrary write and arbitrary jump exploit primitives for ten programs except
for program multi-heap. Results showed that primitive-crucial-behavior
identification and determining exploit primitives are accurate and effective by
using our approach. In addition, DEPA is superior to the state-of-the-art tools
in determining exploit primitives for the heap object internal overflowComment: 11 pages 9 figure
Myofibroblastic conversion of mesothelial cells
Myofibroblastic conversion of mesothelial cells.BackgroundThe continuous chemical, physical, and inflammatory insults of prolonged continuous ambulatory peritoneal dialysis (CAPD) incite mesothelial cell responses, which may result in peritoneal fibrosis. The transforming growth factor-β (TGF-β), especially the isoform TGF-β1, has long been known to play crucial role in the fibrogenic process. Although several studies have implicated TGF-β in peritoneal fibrosis, the underlying mechanism has not been completely elucidated.MethodsTo test the effects of exogenous TGF-β1 on mesothelial cells, we assessed cytoarchitectural changes of human peritoneal mesothelial cells (HPMC) in in vitro culture by light, immunofluorescent, electron and immunoelectron microscopy, and differential gene expression analysis using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and cDNA expression array assays.ResultsThe TGF-β1–induced myofibroblastic conversion was a transdifferentiation process resulting in characteristic myofibroblastic phenotype that included prominent rough endoplasmic reticuli (rER) with dilated cisternas, conspicuous smooth muscle actin (SMA) myofilaments, frequent intercellular intermediate and gap junctions, and active deposition of extracellular matrix (ECM) and formation of fibronexus. The gene expression array analysis revealed complex modulation of gene expression involving cytoskeletal organization, cell adhesion, ECM production, cell proliferation, innate immunity, cytokine/growth factor signaling, cytoprotection, stress response, and many other essential metabolic processes in mesothelial cells.ConclusionThis report describes myofibroblastic conversion of mesothelial cells, a previously undefined, yet frequently speculated, cell adaptive or pathogenic process. Our study helps to elucidate the complex molecular and cellular events involved in myofibroblastic conversion of mesothelial cells. We propose that differentiated epithelial cells of mesothelium convert or transdifferentiate into myofibroblasts, which implies the recruitment of fibrogenic cells from mesothelium during serosal inflammation and wound healing
Higher chromatic rendition with Cr3+-doped yellow Y3Al5O12:Ce3+ for double-layer remote phosphor white-light-emitting diodes
Remote phosphor designs of white-light-emitting diodes (WLEDs) have been recognized for their high thermal stability and excellent luminous efficiency but not for the chromatic rendering. The study presents an approach for the remote phosphor structure to overcome the low-color-rendering issue by enriching its red-light spectral intensity through co-doping Cr3+ and Ce3+ ions into the yellow Y3Al5O12 (YAG) phosphor compound. This ion co-doping process probably enhances emission spectra in the far-red range because of the energy transfer of the integrated ions: Ce3+ Cr3+. Additionally, the luminescence and color properties of the phosphor layer significantly depend on the doped concentration of the Cr3+ ion. Here, with 0.008% Cr3+ in the phosphor composite, either internal or external quantum performances of the dual-layer WLED light are enhanced, which achieved the number of 58.9% and 46.7%, respectively. The color rendering index (CRI) would also be higher if Cr3+ is added, about 77.9, compared to the CRI of 63.2 when using the original YAG:Ce3+ phosphor layer
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