Crystal phase transition of HfO2 films evaporated by plasma-ion-assisted deposition

HfO(2) is a well-known high-refractive-index material for optical interference coatings from the infrared down to the ultraviolet (UV). Dense, homogeneous, and stoichiometric HfO(2) film is critical for low-loss UV optics where the spectral region is close to its fundamental absorption edge. We prepare HfO(2) films by plasma-ion-assisted deposition with various amounts of plasma-ion momentum transfer. The correlation between the HfO(2) film structure and the optical properties are evaluated by a variable-angle spectroscopic ellipsometry, indicating inhomogeneous to homogeneous to inhomogeneous film structural evolution with increasing momentum transfer during deposition. The HfO(2) film inhomogeneity, surface roughness, and crystal phase are confirmed by scanning electron microscopy cross-sectional, atomic force microscopy, and x-ray diffraction measurements. The results suggest that the HfO(2) film structural evolution corresponds to crystal phase transition from weak monocline amorphous to strong monocline depending on the amount of plasma-ion momentum transfer during film deposition.     

Direct low-temperature synthesis of rutile nanostructures in ionic liquids

The direct synthesis of crystalline titania nanorods by sol-gel chemistry in a special ionic liquid is reported. Unexpectedly, the high-temperature modification, rutile, is obtained directly under ambient conditions. X-ray diffraction and high-resolution transmission electron microscopy measurements support the highly crystalline and structural quality of the sample. The phase-directing property of the ionic liquids is attributable to the imide group in the counter ion, which exhibits strong interaction with specific rutile faces. Lithium insertion experiments were performed and revealed high and reversible loading capacities of up to 200 mAh g(-1).     

Metal-enhanced fluorescence of chlorophylls in single light-harvesting complexes

Ensemble and single-molecule spectroscopy demonstrates that both emission and absorption of peridinin-chlorophyll-protein photosynthetic antennae can be largely enhanced through plasmonic interactions. We find up to 18-fold increase of the chlorophyll fluorescence for complexes placed near a silver metal layer. This enhancement, which leaves no measurable effects on the protein structure, is observed when exciting either chlorophyll or carotenoid and is attributed predominantly to an increase of the excitation rate in the antenna. The enhancement mechanism comes from plasmon-induced amplification of electromagnetic fields inside the complex. This result is an important step toward applying plasmonic nanostructures for controlling the optical response of complex biomolecules and improving the design and functioning of artificial light-harvesting systems.     

Analyzing the impact of HRIS implementations on HR personnel’s job satisfaction and turnover intention

An in-depth case of an e-Recruiting system implementation is used while focusing on the level of Human Resource (HR) employees to research unintended consequences during the implementation of Human Resources Information Systems (HRISs). We develop a model that integrates the belief and attitude component of the technology acceptance literature with work-related consequences. We provide evidence for an indirect effect of attitudes toward the HRIS on turnover intention that is fully mediated by job satisfaction. Our results contribute to the literature on systems implementations and technology adoption by suggesting work-related outcomes as important additional success variables.     

Corrosion of an Al–Mg–Si alloy under MgCl2 solution droplets

The corrosion behavior of an Al–0.63Mg–0.28Si alloy under droplets of MgCl₂ solution in environments of 75% and 33% RH was studied using a Kelvin Probe. The equilibrium chloride concentrations in these two environments are 5.8 and 9.8 M chloride, respectively. In the 33% RH environment, metastable pitting was the main form of corrosion. In some cases at 75% RH, the potential baseline decreased slowly by hundreds of millivolts and remained at the lower value. These samples exhibited filiform-like corrosion inside micro-droplets that formed outside of the main MgCl₂ drop. A model for the filiform-like attack in a micro-droplet is presented.     

Non‐equilibrium molecular dynamics simulation of the thermocapillary effect

We report on extended computer simulations of the thermocapillary effect in a model liquid biphasic mixture by employing a nonequilibrium molecular dynamics (NEMD) technique. It maintains a constant temperature gradient in the simulated system. We discuss the methodology used and report, after a careful analysis of the uncertainties inherent to such simulations, first results. The main feature is a stable roll cell convection with flows from hot to cold in the vicinity of the interfaces. This basic pattern persists in systematic variations of the temperature gradients, the size of the simulated systems and several other parameters. We thus assume to be dealing with Marangoni flows (thermocapillary effect) at the microscopic level. © 2012 Canadian Society for Chemical Engineering     

Highly sulfonated poly(phenylene sulfones): optimization of the polymerization conditions

The preparation of highly sulfonated poly(phenylene sulfone) (ion exchange capacity = 4.45 meq g⁻¹) by polycondensation of sulfonated difluorodiphenyl sulfone with metal sulfide and subsequent oxidation with hydrogen peroxide is optimized. The monomer/metal sulfide ratio, polymerization time and temperature, and type of metal sulfide have been varied. For the best conditions high molecular weights of up to 300 kg mol⁻¹ are obtained reproducibly. This high molecular weight polyelectrolyte is meant to be used as main constituent of heterogeneous membrane structures such as interpenetrating networks, polymer blends, or simple physical mixtures with other polymers, e.g., for application in PEM fuel cells.