12,429 research outputs found
Quantum three-body system in D dimensions
The independent eigenstates of the total orbital angular momentum operators
for a three-body system in an arbitrary D-dimensional space are presented by
the method of group theory. The Schr\"{o}dinger equation is reduced to the
generalized radial equations satisfied by the generalized radial functions with
a given total orbital angular momentum denoted by a Young diagram
for the SO(D) group. Only three internal variables are
involved in the functions and equations. The number of both the functions and
the equations for the given angular momentum is finite and equal to
.Comment: 16 pages, no figure, RevTex, Accepted by J. Math. Phy
Harmless treatment of used foundry sands and dewatered municipal sludge by microwave
A new method to treat four solid wastes of sodium silicate used sands, dewatered municipal sludge, clay sands sludge and waste polyethylene, was discussed. About wt/ 50 % sodium silicate used sands and wt/ 50 % dewatered sludge were mixed, and then cured by microwave with a certain thickness film of clay sands sludge and waste plastic of polyethylene in the surface. The results showed that the compression strength of granulation sample with the size of Ф 50 × 50 mm was over 0,45 MPa. The waste plastic was the key factor for the durability, and curing temperature must be over melting temperature, so the thicker film could be coated in the surface of used sands and sludge
Quasienergy spectrum and tunneling current in ac-driven triple quantum dot shuttles
The dynamics of electrons in ac driven double quantum dots have been
extensively analyzed by means of Floquet theory. In these systems, coherent
destruction of tunneling has been shown to occur for certain ac field
parameters. In the present work we analyze, by means of Floquet theory, the
electron dynamics of a triple quantum dot in series attached to electric
contacts, where the central dot position oscillates. In particular, we analyze
the quasienergy spectrum of this ac driven nanoelectromechanical system, as a
function of the intensity and frequency of the ac field and of external dc
voltages. For strong driving fields, we derive, by means of perturbation
theory, analytical expressions for the quasienergies of the driven oscillator
system. From this analysis we discuss the conditions for coherent destruction
of tunneling (CDT) to occur as a function of detuning and field parameters. For
zero detuning, and from the invariance of the Floquet Hamiltonian under a
generalized parity transformation, we find analytical expressions describing
the symmetry properties of the Fourier components of the Floquet states under
such transformation. By using these expressions, we show that in the vicinity
of the CDT condition, the quasienergy spectrum exhibits exact crossings which
can be characterized by the parity properties of the corresponding
eigenvectors
Quantum Manifestations of Graphene Edge Stress and Edge Instability: A First-Principles Study
We have performed first-principles calculations of graphene edge stresses,
which display two interesting quantum manifestations absent from the classical
interpretation: the armchair edge stress oscillates with a nanoribbon width,
and the zigzag edge stress is noticeably reduced by spin polarization. Such
quantum stress effects in turn manifest in mechanical edge twisting and warping
instability, showing features not captured by empirical potentials or continuum
theory. Edge adsorption of H and Stone-Wales reconstruction are shown to
provide alternative mechanisms in relieving the edge compression and hence to
stabilize the planar edge structure.Comment: 5figure
Characterization of a wheat HSP70 gene and its expression in response to stripe rust infection and abiotic stresses
Members of the family of 70-kD heat shock proteins (HSP70 s) play various stress-protective roles in plants. In this study, a wheat HSP70 gene was isolated from a suppression subtractive hybridization (SSH) cDNA library of wheat leaves infected by Puccinia striiformis f. sp. tritici. The gene, that was designated as TaHSC70, was predicted to encode a protein of 690 amino acids, with a molecular mass of 73.54 KDa and a pI of 5.01. Further analysis revealed the presence of a conserved signature that is characteristic for HSP70s and phylogenetic analysis demonstrated that TaHSC70 is a homolog of chloroplast HSP70s. TaHSC70 mRNA was present in leaves of both green and etiolated wheat seedlings and in stems and roots. The transcript level in roots was approximately threefold less than in leaves but light–dark treatment did not charge TaHSC70 expression. Following heat shock of wheat seedlings at 40°C, TaHSC70 expression increased in leaves of etiolated seedlings but remained stable at the same level in green seedlings. In addition, TaHSC70 was differentially expressed during an incompatible and compatible interaction with wheat-stripe rust, and there was a transient increase in expression upon treatment with methyl jasmonate (MeJA) treatment. Salicylic acid (SA), ethylene (ET) and abscisic acid (ABA) treatments had no influence on TaHSC70 expression. These results suggest that TaHSC70 plays a role in stress-related responses, and in defense responses elicited by infection with stripe rust fungus and does so via a JA-dependent signal transduction pathway
Achievable efficiencies for probabilistically cloning the states
We present an example of quantum computational tasks whose performance is
enhanced if we distribute quantum information using quantum cloning.
Furthermore we give achievable efficiencies for probabilistic cloning the
quantum states used in implemented tasks for which cloning provides some
enhancement in performance.Comment: 9 pages, 8 figure
Spatial and seasonal variability of PM<sub>2.5</sub> acidity at two Chinese megacities: insights into the formation of secondary inorganic aerosols
Aerosol acidity is one of the most important parameters influencing atmospheric chemistry and physics. Based on continuous field observations from January 2005 to May 2006 and thermodynamic modeling, we investigated the spatial and seasonal variations in PM<sub>2.5</sub> acidity in two megacities in China, Beijing and Chongqing. Spatially, PM<sub>2.5</sub> was generally more acidic in Chongqing than in Beijing, but a reverse spatial pattern was found within the two cities, with more acidic PM<sub>2.5</sub> at the urban site in Beijing whereas the rural site in Chongqing. Ionic compositions of PM<sub>2.5</sub> revealed that it was the higher concentrations of NO<sub>3</sub><sup>−</sup> at the urban site in Beijing and the lower concentrations of Ca<sup>2+</sup> within the rural site in Chongqing that made their PM<sub>2.5</sub> more acidic. Temporally, PM<sub>2.5</sub> was more acidic in summer and fall than in winter, while in the spring of 2006, the acidity of PM<sub>2.5</sub> was higher in Beijing but lower in Chongqing than that in 2005. These were attributed to the more efficient formation of nitrate relative to sulfate as a result of the influence of Asian desert dust in 2006 in Beijing and the greater wet deposition of ammonium compared to sulfate and nitrate in 2005 in Chongqing. Furthermore, simultaneous increase of PM<sub>2.5</sub> acidity was observed from spring to early summer of 2005 in both cities. This synoptic-scale evolution of PM<sub>2.5</sub> acidity was accompanied by the changes in air masses origins, which were influenced by the movements of a subtropical high over the northwestern Pacific in early summer. Finally, the correlations between [NO<sub>3</sub><sup>−</sup>]/[SO<sub>4</sub><sup>2−</sup>] and [NH<sub>4</sub><sup>+</sup>]/[SO<sub>4</sub><sup>2−</sup>] suggests that under conditions of high aerosol acidity, heterogeneous reactions became one of the major pathways for the formation of nitrate at both cities. These findings provided new insights in our understanding of the spatial and temporal variations in aerosol acidity in Beijing and Chongqing, as well as those reported in other cities in China
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