Raman spectra of hexagonal close-packed iron (varepsilon-Fe) have been measured from 15 to 152 gigapascals by using diamond-anvil cells with ultrapure synthetic diamond anvils. The results give a Gruneisen parameter gamma(0) = 1.68 (+/-0.20) and q = 0.7 (+/-0.5). Phenomenological modeling shows that the Raman-active mode can be approximately correlated with an acoustic phonon and thus provides ...

We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability &mgr;(eff)(omega) and permittivity varepsilon(eff)(omega). This structure forms a "left-handed" medium, for which it has been predicted...

We consider the stochastic heat equation $$\partial _{s}u =\frac{1}{2}\Delta u +(\beta V(s,y)-\lambda )u$$ ? s = 1 2 ? + ( ? V , y ) - ? with a smooth space-time-stationary Gaussian random field V(s, y), in dimensions $$d\ge 3$$ d ? 3 an initial condition $$u(0,x)=u_0(\varepsilon x)$$ 0 x ? and suitably chosen $$\lambda \in {\mathbb {R}}$$ ? R . It is known that, for $$\beta $$ small enough, di...

This work is devoted to studying non-variational, nonlinear singularly perturbed elliptic models enjoying a double degeneracy character with prescribed boundary value in domain. In its simplest form, for each $\varepsilon>0$ fixed, we seek non-negative function $u^{\varepsilon}$ satisfying $$ \begin{cases} \left\[|\nabla u^{\varepsilon}|^p + \mathfrak{a}(x)|\nabla u^{\varepsilon}|^q \right] \De...