36,888 research outputs found
Interaction between graphene and SiO2 surface
With first-principles DFT calculations, the interaction between graphene and
SiO2 surface has been analyzed by constructing the different configurations
based on {\alpha}-quartz and cristobalite structures. The single layer graphene
can stay stably on SiO2 surface is explained based on the general consideration
of configuration structures of SiO2 surface. It is also found that the oxygen
defect in SiO2 surface can shift the Fermi level of graphene down which opens
out the mechanism of hole-doping effect of graphene absorbed on SiO2 surface
observed in experiments.Comment: 17 pages, 7 figure
Long-term Variability Properties and Periodicity Analysis for Blazars
In this paper, the compiled long-term optical and infrared measurements of
some blazars are used to analyze the variation properties and the optical data
are used to search for periodicity evidence in the lightcurve by means of the
Jurkevich technique and the discrete correlation function (DCF) method.
Following periods are found: 4.52-year for 3C 66A; 1.56 and 2.95 years for AO
0235+164;
14.4, 18.6 years for PKS 0735+178; 17.85 and 24.7 years for PKS 0754+100;
5.53 and 11.75 for OJ 287. 4.45, and 6.89 years for PKS 1215; 9 and 14.84 years
for PKS 1219+285;
2.0, 13.5 and 22.5 for 3C273; 7.1 year for 3C279;
6.07 for PKS 1308+326; 3.0 and 16.5 years for PKS 1418+546;
2.0 and 9.35 years for PKS 1514-241; 18.18 for PKS 1807+698;
4.16 and 7.0 for 2155-304; 14 and 20 years for BL Lacertae. Some explanations
have been discussed.Comment: 10 pages, 2 table, no figure, a proceeding paper for Pacific Rim
Conference on Stellar Astrophysics, Aug. 1999, HongKong, Chin
Characterization of the residual stresses in spray-formed steels using neutron diffraction
Neutron diffraction was used to characterize the residual stresses in an as-sprayed tube-shaped steel preform. The measured residual stress distributions were compared with those simulated using finite element method by taking into account the effects of the thermal history, porosity and different phases of the sprayed preform. The porosity was measured using X-ray microcomputed tomography. The study revealed for the first time the correlation between the distribution of porosity and residual stress developed in the as-sprayed preform
Influence of tensor interactions on masses and decay widths of dibaryons
The influence of gluon and Goldstone boson induced tensor interactions on the
dibaryon masses and D-wave decay widths has been studied in the quark
delocalization, color screening model. The effective S-D wave transition
interactions induced by gluon and Goldstone boson exchanges decrease rapidly
with increasing strangeness of the channel. The tensor contribution of K and
mesons is negligible in this model. There is no six-quark state in the
light flavor world studied so far that can become bound by means of these
tensor interactions besides the deuteron. The partial D-wave decay widths of
the N state to spin 0 and 1 final states
are 12.0 keV and 21.9 keV respectively. This is a very narrow dibaryon
resonance that might be detectable in relativistic heavy ion reactions by
existing RHIC detectors through the reconstruction of the vertex mass of the
decay product and by the COMPAS detector at CERN or at JHF in
Japan and the FAIR project in Germany in the future.Comment: 19 pages, 5 figure
Identification of key water quality characteristics affecting the filterability of biologically treated effluent in low-pressure membrane filtration
There are many water quality characteristics which could influence the filterability of biologically treated effluent from Melbourne's Western Treatment Plant (WTP). Statistical correlation was used to identify the key water characteristics affecting the microfiltration (MF) and ultrafiltration (UF) filterability in terms of permeate volume of the treated effluent. The models developed showed that turbidity, dissolved organic carbon (DOC) and total suspended solids (TSS) were the key factors which influenced the MF and UF filterability. Turbidity was the dominant factor affecting the accuracy of the model for MF filterability while DOC was the major factor affecting the accuracy of the model for UF filterability. A prediction accuracy of 85% was obtained for MF and 86% for UF filterability of the WTP effluent. The characteristics of the organic components of the wastewater were demonstrated by EEM spectra to have seasonal variation which would have reduced the prediction accuracy. As turbidity, DOC and TSS can be determined on-line, the models would be useful for rapid prediction of the filterability of WTP effluent and this may assist the control of low-pressure membrane filtration processes
The electro production of d* dibaryon
dibaryon study is a critical test of hadron interaction models. The
electro production cross sections of have been calculated based on
the meson exchange current model and the cross section around 30 degree of 1
GeV electron in the laboratory frame is about 10 nb. The implication of this
result for the dibaryon search has been discussed.Comment: 12 pages, 12 figures, Late
Generalized thermo vacuum state derived by the partial trace method
By virtue of the technique of integration within an ordered product (IWOP) of
operators we present a new approach for deriving generalized thermo vacuum
state which is simpler in form that the result by using the Umezawa-Takahashi
approach, in this way the thermo field dynamics can be developed. Applications
of the new state are discussed.Comment: 5 pages, no figure, revtex
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