310 research outputs found
A correspondence and distance of t-structures
For two t-structures and
with on a triangulated category , we
give a correspondence between t-structure which satisfies and a pair of full
subcategories of . Then we give
a way to determine the distance of two t-structure if we have known that their
distance is finite.In addition, if we set a t-structure whose heart
and that has a non-trivial torsion pair, then for any
integer , we can construct a t-structure such that the distance
between and is .Comment: 13 pages. Any comments are welcom
Interfacial thermal conductance in graphene/black phosphorus heterogeneous structures
Graphene, as a passivation layer, can be used to protect the black phosphorus
from the chemical reaction with surrounding oxygen and water. However, black
phosphorus and graphene heterostructures have low efficiency of heat
dissipation due to its intrinsic high thermal resistance at the interfaces. The
accumulated energy from Joule heat has to be removed efficiently to avoid the
malfunction of the devices. Therefore, it is of significance to investigate the
interfacial thermal dissipation properties and manipulate the properties by
interfacial engineering on demand. In this work, the interfacial thermal
conductance between few-layer black phosphorus and graphene is studied
extensively using molecular dynamics simulations. Two critical parameters, the
critical power Pcr to maintain thermal stability and the maximum heat power
density Pmax with which the system can be loaded, are identified. Our results
show that interfacial thermal conductance can be effectively tuned in a wide
range with external strains and interracial defects. The compressive strain can
enhance the interfacial thermal conductance by one order of magnitude, while
interface defects give a two-fold increase. These findings could provide
guidelines in heat dissipation and interfacial engineering for thermal
conductance manipulation of black phosphorus-graphene heterostructure-based
devices.Comment: 33 pages, 22 figure
Detecting Cosmic 21 cm Global Signal Using an Improved Polynomial Fitting Algorithm
Detecting the cosmic 21 cm signal from Epoch of Reionization (EoR) has always
been a difficult task. Although the Galactic foreground can be regarded as a
smooth power-law spectrum, due to the chromaticity of the antenna, additional
structure will be introduced into the global spectrum, making the polynomial
fitting algorithm perform poorly. In this paper, we introduce an improved
polynomial fitting algorithm - the Vari-Zeroth-Order Polynomial (VZOP) fitting
and use it to fit the simulation data. This algorithm is developed for the
upcoming Low-frequency Anechoic Chamber Experiment (LACE), yet it is a general
method suitable for application in any single antenna-based global 21 cm signal
experiment. VZOP defines a 24-hour averaged beam model that brings information
about the antenna beam into the polynomial model. Assuming that the beam can be
measured, VZOP can successfully recover the 21 cm absorption feature, even if
the beam is extremely frequency-dependent. In real observations, due to various
systematics, the corrected measured beam contains residual errors that are not
completely random. Assuming the errors are frequency-dependent, VZOP is capable
of recovering the 21 cm absorption feature even when the error reaches 10%.
Even in the most extreme scenario where the errors are completely random, VZOP
can at least give a fitting result that is not worse than the common polynomial
fitting. In conclusion, the fitting effect of VZOP depends on the structure of
the error and the accuracy of the beam measurement.Comment: 14 pages, 15 figures, Accepted for publication in MNRA
Some Predictions of Deformations from Tram Track Construction in a Structure-Embankment Transition Zone
AbstractBased on a construction project of a tram line in Nanjing City of China, the influence of a tram track construction on the deformation characteristics of an adjacent metro station and tunnels is investigated. Because a section of the tram track is designed to be constructed in the vicinity of the connection between a metro station and metro tunnels, the foundation of the tram track is changed from the station structure to the normal embankment. As a result, deformations from tram track construction in this structure-embankment transition zone will be serious. In order to protect the metro station and the twin tunnels from the construction-induced deformation and long term settlement caused by tram trains, a recommended treatment of the structure-embankment transition zone is suggested according to the property of the surrounding soils. The construction process of the tram track over the metro station and the tunnels is simulated by a finite element analysis (FEA) method. The deformation characteristics of the metro station and tunnels are calculated. Results indicate that with the recommended transition zone design the deformation response of the adjacent underground structures can be well controlled and the transition performance of the tram track transition zone can be improved
Optimized sample preparation for two-dimensional gel electrophoresis of soluble proteins from chicken bursa of Fabricius
<p>Abstract</p> <p>Background</p> <p>Two-dimensional gel electrophoresis (2-DE) is a powerful method to study protein expression and function in living organisms and diseases. This technique, however, has not been applied to avian bursa of Fabricius (BF), a central immune organ. Here, optimized 2-DE sample preparation methodologies were constructed for the chicken BF tissue. Using the optimized protocol, we performed further 2-DE analysis on a soluble protein extract from the BF of chickens infected with virulent avibirnavirus. To demonstrate the quality of the extracted proteins, several differentially expressed protein spots selected were cut from 2-DE gels and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).</p> <p>Results</p> <p>An extraction buffer containing 7 M urea, 2 M thiourea, 2% (w/v) 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS), 50 mM dithiothreitol (DTT), 0.2% Bio-Lyte 3/10, 1 mM phenylmethylsulfonyl fluoride (PMSF), 20 U/ml Deoxyribonuclease I (DNase I), and 0.25 mg/ml Ribonuclease A (RNase A), combined with sonication and vortex, yielded the best 2-DE data. Relative to non-frozen immobilized pH gradient (IPG) strips, frozen IPG strips did not result in significant changes in the 2-DE patterns after isoelectric focusing (IEF). When the optimized protocol was used to analyze the spleen and thymus, as well as avibirnavirus-infected bursa, high quality 2-DE protein expression profiles were obtained. 2-DE maps of BF of chickens infected with virulent avibirnavirus were visibly different and many differentially expressed proteins were found.</p> <p>Conclusion</p> <p>These results showed that method C, in concert extraction buffer IV, was the most favorable for preparing samples for IEF and subsequent protein separation and yielded the best quality 2-DE patterns. The optimized protocol is a useful sample preparation method for comparative proteomics analysis of chicken BF tissues.</p
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