5,228 research outputs found
On small energy stabilization in the NLKG with a trapping potential
We consider a nonlinear Klein Gordon equation (NLKG) with short range
potential with eigenvalues and show that in the contest of complex valued
solutions the small standing waves are attractors for small solutions of the
NLKG. This extends the results already known for the nonlinear Schr\"odinger
equation and for the nonlinear Dirac equation. In addition, this extends a
result of Bambusi and Cuccagna (which in turn was an extension of a result by
Soffer and Weinstein) which considered only real valued solutions of the NLKG
Doping change and distortion effect on double-exchange ferromagnetism
Doping change and distortion effect on the double-exchange ferromagnetism are
studied within a simplified double-exchange model. The presence of distortion
is modelled by introducing the Falicov-Kimball interaction between itinerant
electrons and classical variables. By employing the dynamical mean-field theory
the charge and spin susceptibility are exactly calculated. It is found that
there is a competition between the double-exchange induced ferromagnetism and
disorder-order transition. At low temperature various long-range order phases
such as charge ordered and segregated phases coexist with ferromagnetism
depending on doping and distortion. A rich phase diagram is obtained.Comment: 8 pages, 8 figure
Properties of Generalized Forchheimer Flows in Porous Media
The nonlinear Forchheimer equations are used to describe the dynamics of
fluid flows in porous media when Darcy's law is not applicable. In this
article, we consider the generalized Forchheimer flows for slightly
compressible fluids and study the initial boundary value problem for the
resulting degenerate parabolic equation for pressure with the time-dependent
flux boundary condition. We estimate -norm for pressure and its time
derivative, as well as other Lebesgue norms for its gradient and second spatial
derivatives. The asymptotic estimates as time tends to infinity are emphasized.
We then show that the solution (in interior -norms) and its gradient
(in interior -norms) depend continuously on the initial and
boundary data, and coefficients of the Forchheimer polynomials. These are
proved for both finite time intervals and time infinity. The De Giorgi and
Ladyzhenskaya-Uraltseva iteration techniques are combined with uniform
Gronwall-type estimates, specific monotonicity properties, suitable parabolic
Sobolev embeddings and a new fast geometric convergence result.Comment: 63 page
Linear response within the projection-based renormalization method: Many-body corrections beyond the random phase approximation
The explicit evaluation of linear response coefficients for interacting
many-particle systems still poses a considerable challenge to theoreticians. In
this work we use a novel many-particle renormalization technique, the so-called
projector-based renormalization method, to show how such coefficients can
systematically be evaluated. To demonstrate the prospects and power of our
approach we consider the dynamical wave-vector dependent spin susceptibility of
the two-dimensional Hubbard model and also determine the subsequent magnetic
phase diagram close to half-filling. We show that the superior treatment of
(Coulomb) correlation and fluctuation effects within the projector-based
renormalization method significantly improves the standard random phase
approximation results.Comment: 17 pages, 7 figures, revised versio
The Effect of the Difference in the Perception of Temperature Between Sexes on the Academic Performance of Chapin High School Students
Mental performance and mental functions may be negatively affected by decreases in thermal comfort as a result of large differences in temperature. Additionally, females are seen to be less content with room temperatures and actually prefer rooms with higher temperatures in comparison to males. This investigation explored the potential effect that sex plays in thermal perception and the impact it may yield on academic performance within a high school population. It was hypothesized that female students would experience an increase in academic performance as the temperature increased while males would experience the opposite effect. A quasi-experimental approach was used to address the potential correlation. A SAT preparation class at Chapin High School was asked to complete a Google form that recorded their sex and contained 24 SAT style questions. This process was repeated on three different days within the same classroom setting where the temperature was manipulated to 67, 72, and 78 degrees Fahrenheit on each day. Analysis of Variance (ANOVA) and Tukey’s method tests were performed to analyze the relationship between thermal perception and academic performance. The ANOVA test resulted in a p-value of 0.049 between the means of temperataure and sex, which indicated that there was statistical significance regarding correlation between differences in thermal perception and academic achievement. Additionally, through Tukey’s method, the results calculated three significant T-values that served as evidence against the null hypothesis. Based on these findings, it is concluded that male academic performance increased as temperature increased, while female academic performance increased as temperature decreased
Fabrication of Twin-well CMOS
A single-mask self aligned Twin-well process has been integrated into RIT’s CMOS technology. These wells are self aligned to increase package density. The process has been simulated using TMA Suprem IV simulation tool. The simulated parameters were used in the actual fabrication. The wells are used to optimize both n- and p-channel active devices. The subthreshold leakage currents in isolated pmos and nmos devices are -1.28 pA.4/μn and 3.56 nA/μm of channel width, respectively when the devices were biased at \u3c 5 volts. In addition, the twinwell process has produced active n- and p-channel FET’s with excellent characteristics such as low threshold voltage, low subthreshold swing, and high transconductance
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