Two-Phase Problems for Linear Elliptic Operators with Variable Coefficients: Lipschitz Free Boundaries are <Emphasis Type="Italic">C</Emphasis><Superscript><Emphasis Type="Italic">1,γ</Emphasis></Superscript>

We prove C ^1, regularity of Lipschitz free boundaries of two-phase problems for linear elliptic operators with Hölder continuous coefficients.     

Quasicrystalline electronic states of a one-dimensionally modulated Ag film

Ag films on GaAs(110) exhibit a one-dimensional quasiperiodic modulation, resulting in a Fibonacci sequence of parallel stripes with two different widths. Valence level photoemission shows that the Ag electronic states acquire a unique character along the quasiperiodic direction, distinctively manifested by a hierarchy of energy level replicas and avoided crossings at characteristic intervals in reciprocal space. These observations demonstrate the strong influence of the one-dimensional quasiperiodic potential on the Ag film states.     

Lorentz violation in the linearized gravity

We study some physical consequences of the introduction of a Lorentz-violating modification term in the linearized gravity, which leads to modified dispersion relations for gravitational waves in the vacuum. We discuss two possible mechanisms for the induction of such a term in the Lagrangian. First, it is generated at the quantum level by a Lorentz-breaking coupling of the gravity field to a spinor field. Second, it appears as consequence of a particular modification of the Poisson algebra of the canonical variables, in the spirit of the so-called “noncommutative fields approach”.     

Scalable silicon nanowire photodetectors

This paper presents photodetectors having vertically stacked electrodes with sub-micron (300 nm) separation based on silicon nanowire (SiNW) nanocomposites. The thin-film-like devices are made using standard photolithography instead of electron beam lithography and thus are amenable to scalable low-cost manufacturing. The processing technique is not limited to SiNWs and can be extended to different nanowires (NWs) (e.g., ZnO, CdSe) and substrates. The current–voltage characteristics show Schottky behaviour that is dependent on the properties of the contact metal and that of the pristine SiNWs. This makes these devices suitable for examination of electronic transport in SiNWs. Preliminary results for light sensitivity show promising photoresponse that is a function of effective NW density.     

How glucosylation triggers physical–chemical properties of curcumin: an experimental and theoretical study

In the present study, we investigate the structures of glucosylated curcumin derivatives with DFT at B3LYP/6‐31G* level. A conformational analysis is performed in order to determine the conformational minimum (GS) and rotational transition state (TS) of curcumin derivatives and then their electronic features are evaluated. HOMO and LUMO frontier orbitals and maps of electron density potential (MEPs) are plotted and compared. In order to correlate their predicted spectroscopic properties with IR, UV–vis and NMR experimental data we extended the theoretical study on electronic properties to different solvents (H₂O, MeOH, ACN, DMSO). The main finding is that the curcuminic core maintains the same geometrical and electronic structures in all compounds miming the metal coordination capability showed by curcumin. Therefore, we may confirm that the presence of glucose does not affect the electronic properties of the derivatives. Copyright © 2010 John Wiley & Sons, Ltd.     

On the superfield effective potential in three dimensions

We develop the superfield approach to the effective potential in three dimensions and calculate the one-loop and two-loop Kählerian effective potential in commutative and noncommutative cases.     

L‐lysine and EDTA polymer mimics as resins for the quantitative and reversible removal of heavy metal ion water pollutants

Traditional precipitation methods for inorganic micropollutant removal from waters are increasingly being replaced by sorption methods based on both natural and synthetic materials. In this context, two novel effective heavy metal ions absorbers are presented. These resins, LYMA and LMT85, were crosslinked poly(amidoamine)s carrying amine and carboxyl groups in their repeating units. In particular, the LYMA‐repeating unit contains one carboxyl and two amine groups and is a mimic of L ‐lysine, whereas LMT85 contains two amine and five carboxyl groups and is a mimic of EDTA. Both resins were prepared at moderate cost by simple eco‐friendly procedures. The heavy metal ion set adopted as benchmark was Cu²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Ni²⁺, and Co²⁺. LYMA proved selective for Cu²⁺ and Ni²⁺, the other ions tested being negligibly absorbed, whereas LMT85 proved capable of rapidly and quantitatively absorbing all the ions tested either singly or in mixed solution. The absorption process was reversible, and the resins were easily regenerated by acidification. The absorption of several metal ions imparted intense coloring to the resins, a feature possibly exploitable for analytical purposes. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

X-ray double-crystal rocking curves in GaAlAs/GaAs heterostructures

Summary X-ray double-crystal rocking curves of Ga_1−x Al _x As/GaAs heterostructures have been calculated using a dynamical diffraction model for the general case of Bragg reflection geometry. Different experimental configurations have been considered and the possibility of studying both slightly mismatched and relatively thin layers has been investigated. Experimental rocking curves have been measured using the CuKα ₁ radiation, the 004 symmetric reflection and a perfect crystal as the monochromator. An excellent agreement between calculated and experimental rocking curves has been found and this demonstrates the reliability of both the experimental procedure and the theoretical approach.     

Shot noise in linear macroscopic resistors

We report on direct experimental evidence of shot noise in a linear macroscopic resistor. The origin of the shot noise comes from the fluctuation of the total number of charge carriers inside the resistor associated with their diffusive motion under the condition that the dielectric relaxation time becomes longer than the dynamic transit time. The present results show that neither potential barriers nor the absence of inelastic scattering are necessary to observe shot noise in electronic devices.