12,429 research outputs found

    Quantum three-body system in D dimensions

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    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 [μ,ν,0,...,0][\mu,\nu,0,...,0] 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 (μν+1)(\mu-\nu+1).Comment: 16 pages, no figure, RevTex, Accepted by J. Math. Phy

    Harmless treatment of used foundry sands and dewatered municipal sludge by microwave

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    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

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    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

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    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

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    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

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    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

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    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>&minus;</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>&minus;</sup>]/[SO<sub>4</sub><sup>2&minus;</sup>] and [NH<sub>4</sub><sup>+</sup>]/[SO<sub>4</sub><sup>2&minus;</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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