7,825 research outputs found
Algebraic Cayley Graphs over Finite Fields
A new algebraic Cayley graph is constructed using finite fields. Its
connectedness and diameter bound are studied via Weil's estimate for character
sums. These graphs provide a new source of expander graphs, extending classical
results of Chung
Universal Thermoelectric Effect of Dirac Fermions in Graphene
We numerically study the thermoelectric transports of Dirac fermions in
graphene in the presence of a strong magnetic field and disorder. We find that
the thermoelectric transport coefficients demonstrate universal behavior
depending on the ratio between the temperature and the width of the
disorder-broadened Landau levels(LLs). The transverse thermoelectric
conductivity reaches a universal quantum value at the center of
each LL in the high temperature regime, and it has a linear temperature
dependence at low temperatures. The calculated Nernst signal has a peak at the
central LL with heights of the order of , and changes sign near other
LLs, while the thermopower has an opposite behavior, in good agreement with
experimental data. The validity of the generalized Mott relation between the
thermoelectric and electrical transport coefficients is verified in a wide
range of temperatures.Comment: 4 pages, 4 figures, published versio
Effect of low intensity pulsed ultrasound on repairing the periodontal bone of Beagle canines
AbstractObjectiveTo investigate the repairing effect of low intensity pulsed ultrasound (LIPUS) on the Beagle canines periodontal bone defect.MethodsA total of 12 Beagle dogs with periodontal bone defect model were randomly divided into control group, LIPUS group, guided tissue regeneration (GTR) group and LIPUS+GTR group, with three in each. After completion of the models, no other proceeding was performed in control group; LIPUS group adopt direct exposure to radiation line LIPUS processing 1 week after modeling; GTR group adopted treatment with GTR, following the CTR standard operation reference; LIPUS+GTR group was treated with LIPUS joint GTR. Temperature change before treatment and histopathological change of periodontal tissue after repair was observed.ResultsThere was no significant difference in temperature changes of periodontal tissue between groups (P>0.05). The amount and maturity of LIPUS+GTR group were superior to other groups; new cementum, dental periodontal bones of GTR group were superior to the control group but less than LIPUS group; new collagen and maturity of the control group is not high relatively.ConclusionsLIPUS can accelerate the calcium salt deposition and new bone maturation, thus it can serve as promoting periodontal tissue repair, and shortening the periodontal tissue repair time
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