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1.
Spenta R Wadia 《Pramana》1997,49(1):71-80
We report some progress on the quark confinement problem in 2 + 1 dim. pure Yang-Mills theory, using Euclidean instanton methods.
The instantons are regularized Wu-Yang ‘monopoles’, whose long range Coulomb field is screened by collective effects. Such
configurations are stable to small perturbations unlike the case of singular, undressed monopoles. Using exact non-perturbative
results for the 3-dim. Coulomb gas, where Debye screening holds for arbitrarily low temperatures, we show in a self-consistent
way that a mass gap is dynamically generated in the gauge theory. The mass gap also determines the size of the monopoles.
We also identify the disorder operator of the model in terms of the Sine-Gordon field of the Coulomb gas and hence obtain
a dual representation whose symmetry is the centre ofSU(2). 相似文献
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Aspi Rustom Wadia 《国际流体数值方法杂志》1985,5(2):191-198
The non-linear two-point boundary value problem for three-dimensional compressible boundary layers is solved through the application of a boundary value technique for a range of parameters characterizing the nature of stagnation point flows. The analytical boundary conditions, at infinity, are applied at the edge of the computational mesh with iterations on the size of the domain. The solutions obtained show excellent agreement with the established similarity solutions for three-dimensional flows. The present method has the potential advantage of yielding the wall values of f″w, g″w and θ′w as a part of the solution, contrary to the previously used ‘shooting’ methods. The algorithm is computationally simple and numerically stable and extremely suitable for engineering design applications. 相似文献
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Auerbach LB Burman RL Caldwell DO Church ED Cochran AK Donahue JB Fazely AR Garvey GT Gunasingha RM Imlay RL Kahrimanis G Louis WC Majkic R Malik A McIlhany KL Metcalf WJ Mills GB Rupnik D Sandberg VD Smith D Somodi RF Stancu I Strossman WD Sung M Tayloe R VanDalen GJ Vernon W Wadia N White DH Yellin S Yi H;LSND Collaboration 《Physical review letters》2004,92(9):091801
We observe a net beam excess of 8.7+/-6.3(stat)+/-2.4(syst) events, above 160 MeV, resulting from the charged-current reaction of nu(micro) and/or nu;(mu) on C and H in the LSND detector. No beam-related muon background is expected in this energy regime. Within an analysis framework of pi(0)-->nu(mu)nu;(mu), we set a direct upper limit for this branching ratio of Gamma(pi(0)-->nu(mu)nu;(mu))/Gamma(pi(0)-->all)<1.6 x 10(-6) at 90% confidence level. 相似文献
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Amand Faessler M. Ismail N. Ohtsuka M. Rashdan W. Wadia 《Zeitschrift für Physik A Hadrons and Nuclei》1987,326(4):501-508
A recent approach for calculating both the real and imaginary parts of the ion-ion potential has been modified to produce the ground state properties of separate nuclei. This approach is used to study both the energy and orientation dependence of the optical potential between two U nuclei adopting the sudden and adiabatic approximations. 相似文献
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A. Wahby Z. Abdelouahab-Reddam R. El?Mail M. Stitou J. Silvestre-Albero A. Sepúlveda-Escribano F. Rodríguez-Reinoso 《Adsorption》2011,17(3):603-609
The textural characterization of a series of activated carbons prepared from olive stones, by carbonization at different temperatures
(400, 550, 700 and 850 °C) and thermal activation with CO2, has been investigated using N2 adsorption at −196 °C and CO2 adsorption at 0 °C. The effect of pre-oxidation of the carbonized precursor has also been studied, using temperature-programmed
decomposition (TPD), to evaluate the effect of oxygen content of the chars in the performance of the obtained activated carbons
for mercury removal. The adsorption of Hg(II) cations from aqueous solutions at room temperature by the prepared activated
carbons was studied. Experimental results show that all samples exhibit a large microporosity (pore diameter below 0.56 nm).
The amount of surface oxygen groups increased after pre-oxidation treatment, this enhancing the Hg(II) uptake (up to 72%).
It can be concluded that these groups make the support more hydrophilic, thus providing a more efficient adsorption of Hg(II).
The formation of a great amount of surface oxide groups such as carboxyl, phenol and lactone alters the surface charge properties
of the carbon, this enhancing the surface-Hg(II) interaction. 相似文献
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A. Faessler M. Rashdan M. Ismail N. Ohtsuka W. Wadia 《Zeitschrift für Physik A Hadrons and Nuclei》1989,333(2):153-162
The effect of nuclear and Coulomb interactions on the shapes of two colliding208Pb nuclei at finite temperature is investigated. The complex potential energy density derived by Faessler and collaborators and the kinetic energy density and entropy density for two Fermi spheres at finite temperature are used to calculate the free energy of the208Pb +208Pb system in the energy density formalism. Shell corrections are added to the free energy in the framework of the Strutinsky method. The total free energy is minimized with respect to the quadrupole deformation and the diffuseness to determine the density distribution of208Pb nucleus at certain distanceR and temperatureT assuming the deformed Woods-Saxon shape for each nucleus. It is found that the nucleus acquires larger deformation and diffuseness as the temperature increases. The interaction potential between two208Pb nuclei is calculated from the minimized free energy. The total (nuclear + Coulomb) potential is found to decrease with increasing temperature, whereas the real part of the nuclear potential becomes more repulsive as the temperature increases. 相似文献
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M. Rashdan A. Faessler N. Ohtsuka R. Linden W. Wadia M. Ismail 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(4):417-421
Using a complex energy density functional derived from the Reid soft-core potential, the changes in nuclear shapes of two colliding208Pb are investigated. At each separation distanceR, the total binding energy of the Pb + Pb system is minimized w.r.t. the quadrupole deformation and diffuseness parameters of nuclear densities. It is found that the nuclear shapes are strongly affected by the nuclear and Coulomb interactions. A sudden transition occurs from oblate to prolate shapes around R16.8fm and a smooth one from prolate to oblate shapes aroundR?11.76 fm. 相似文献