Influence of Substrate Temperature and Post-Deposition Annealing on Material Properties of Ga-Doped ZnO Prepared by Pulsed Laser Deposition

Ga-doped ZnO films were prepared at 10 mTorr of oxygen over a broad temperature range using pulsed laser deposition. The carrier concentration of as-deposited films decreased monotonically with deposition temperature over a temperature range of 25°C to 450°C. Post-deposition annealing of as-deposited films in forming gas (5% H₂ in argon) or vacuum resulted in a substantial increase in both carrier concentration and electron mobility. The figure of merit was highest for films deposited at 250°C then annealed in forming gas at 400°C. The optical transmittance was near 90% throughout the visible and near-infrared spectral regions. These results indicate that Ga-doped ZnO is a viable alternative to transparent indium-based conductive oxides.     

Female sexual responses in male cats facilitated by olfactory bulbectomy and medial preoptic/anterior hypothalamic lesions.

Using 23 sexually active male cats, the authors performed bilateral lesions of the medial preoptic/anterior hypothalamic area and olfactory bulbectomies, with the order of operations balanced. In all Ss, male sexual behavior was virtually eliminated by the combined operations. Increased levels of female proceptive behavior were seen after either type of lesion alone, and combined operations resulted in increased levels of receptivity. Results support the concept that there exists, within the brains of male animals, the neural basis for the display of female as well as male sexual responses and that certain brain operations may potentiate the display of female responses. However, it does not appear that the reduction of male behavior is necessarily coupled with an increase in female behavior, since no correlation was seen between the degree of enhancement of female behavior and the decrement in male behavior. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flyweight,Superelastic, Electrically Conductive,and Flame‐Retardant 3D Multi‐Nanolayer Graphene/Ceramic Metamaterial

A ceramic/graphene metamaterial (GCM) with microstructure‐derived superelasticity and structural robustness is achieved by designing hierarchical honeycomb microstructures, which are composited with two brittle constituents (graphene and ceramic) assembled in multi‐nanolayer cellular walls. Attributed to the designed microstructure, well‐interconnected scaffolds, chemically bonded interface, and coupled strengthening effect between the graphene framework and the nanolayers of the Al₂O₃ ceramic (NAC), the GCM demonstrates a sequence of multifunctional properties simultaneously that have not been reported for ceramics and ceramics–matrix–composite structures, such as flyweight density, 80% reversible compressibility, high fatigue resistance, high electrical conductivity, and excellent thermal‐insulation/flame‐retardant performance simultaneously. The 3D well‐ordered graphene aerogel templates are strongly coupled with the NAC by the chemically bonded interface, exhibiting mutual strengthening, compatible deformability, and a linearly dependent relationship between the density and Young's modulus. Considerable size effects of the ceramic nanolayers on the mechanical properties are revealed in these ceramic‐based metamaterials. The designed hierarchical honeycomb graphene with a fourth dimensional control of the ceramic nanolayers on new ways to scalable fabrication of advanced multifunctional ceramic composites with controllable design suggest a great potential in applications of flexible conductors, shock/vibration absorbers, thermal shock barriers, thermal insulation/flame‐retardant skins, and porous microwave‐absorbing coatings.     

Spontaneous, non-aqueous electrochemical deposition of copper and palladium on Al and Al(Cu) thin films

Copper and palladium seed layers have been successfully deposited from organic solutions onto patterned and unpatterned pure aluminum and Al(0.5%Cu) thin films using an immersion displacement process. The reaction occurs at ambient temperature and pressure by a spontaneous electrochemical mechanism. Copper and palladium deposition using the organic solution was studied as a function of reaction time and Cu or Pd concentration in the solution. It was found that both time and the intial ionic metal concentration significantly influence deposit morphology, particle size and shape, and adherence. Nucleation of Cu or Pd sub-micron particles on both Al and Al(Cu) surfaces occurred in less than one minute while nucleation density and particle size increased with longer deposition times. Increasing the copper or palladium concentration in the organic solution resulted in an increase in the final particle size of the seed crystals. However, an increase in deposition time and metal concentration in the organic solution caused more extensive dissolution and pitting of the aluminum thin films. The Cu and Pd deposits were effectively used as catalytic sites for subsequent electroless or electrolytic copper deposition using conventional aqueous processes.