1,220 research outputs found
Improving gas sensing properties of graphene by introducing dopants and defects: a first-principles study
The interactions between four different graphenes (including pristine, B- or N-doped and defective graphenes) and small gas molecules (CO, NO, NO2 and NH3) were investigated by using density functional computations to exploit their potential applications as gas sensors. The structural and electronic properties of the graphene-molecule adsorption adducts are strongly dependent on the graphene structure and the molecular adsorption configuration. All four gas molecules show much stronger adsorption on the doped or defective graphenes than that on the pristine graphene. The defective graphene shows the highest adsorption energy with CO, NO and NO2 molecules, while the B- doped graphene gives the tightest binding with NH3. Meanwhile, the strong interactions between the adsorbed molecules and the modified graphenes induce dramatic changes to graphene's electronic properties. The transport behavior of a gas sensor using B- doped graphene shows a sensitivity two orders of magnitude higher than that of pristine graphene. This work reveals that the sensitivity of graphene-based chemical gas sensors could be drastically improved by introducing the appropriate dopant or defect
The impacts of magnetic fields on the thermocapillary convection in two layers fluid system
Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.Under a horizontal temperature gradient along the liquidliquid
interface, the developing processes of thermocapillary
convection in two layers immiscible fluids system absent
gravity were simulated numerically, where the upper layer fluid
was encapsulant B2O3, the underlayer fluid was melting InP in
this paper. The effects of different direction magnetic field on
the developing behaviors of thermocapillary convection were
investigated. The results showed that the flow pattern was
changed obviously and the thermocapillary convection was
damped in some extent and the temperature distributions
became more uniform if magnetic fields in X, Y or Z direction
were applied. Z direction magnetic field had a stronger effect
on the thermocapillary convection and it was enough to
suppress convection significantly at Bz between 0.15T and 0.2T.
The simulation became numerically unstable when Bz was over
0.2T.cs201
Onsager Relations and Hydrodynamic Balance Equations in 2D Quantum Wells
In this letter we clarify the role of heat flux in the hydrodynamic balance
equations in 2D quantum wells, facilitating the formulation of an Onsager
relation within the framework of this theory. We find that the Onsager relation
is satisfied within the framework of the 2D hydrodynamic balance equation
transport theory at sufficiently high density. The condition of high density is
consonant with the requirement of strong electron-electron interactions for the
validity of our balance equation formulation.Comment: 11 pages, RevTex, 4 postscript figures are avaliable upon reques
Identification and data-driven model reduction of state-space representations of lossless and dissipative systems from noise-free data
We illustrate procedures to identify a state-space representation of a lossless- or dissipative system from a given noise-free trajectory; important special cases are passive- and bounded-real systems. Computing a rank-revealing factorization of a Gramian-like matrix constructed from the data, a state sequence can be obtained; state-space equations are then computed solving a system of linear equations. This idea is also applied to perform model reduction by obtaining a balanced realization directly from data and truncating it to obtain a reduced-order mode
Heterostructured III-V Nanowires with Mixed Crystal Phases Grown by Au-Assisted Molecular Beam Epitaxy
Coupled Effects of Strain Rate and Temperature on Deformation Twinning in Cu-Zn Alloy
Cu-Zn alloy is an advanced material, but its deformation twinning mechanism still keeps unknown so far, especially the couple effects of temperature and strain rate. In this paper, a theoretical model of Cu-Zn alloy is proposed by considering the coupled effects of strain rate and temperature. The model can predict the experimentally observed tendency of the spacing evolution of twin boundary (TB) accurately, and it is known that low temperature and high strain rate will promote deformation twinning. Moreover, deformation twining is more susceptible to low temperature than to high strain rate, and TB spacing and twin layer thickness will decrease with high strain rate and low temperature
Higgs-Boson Production Associated with a Single Bottom Quark in Supersymmetric QCD
Due to the enhancement of the couplings between Higgs boson and bottom quarks
in the minimal sypersymmetric standard model (MSSM), the cross section of the
process pp(p\bar{p}) \to h^0b(h^0\bar{b})+X at hadron colliders can be
considerably enhanced. We investigated the production of Higgs boson associated
with a single high-p_T bottom quark via subprocess bg(\bar{b}g) \to
h^0b(h^0\bar{b}) at hadron colliders including the next-to-leading order (NLO)
QCD corrections in MSSM. We find that the NLO QCD correction in the MSSM
reaches 50%-70% at the LHC and 60%-85% at the Fermilab Tevatron in our chosen
parameter space.Comment: accepted by Phys. Rev.
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