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An analysis of the intervalence charge-transfer (IVCT) band of (E)-4,4'-Bis{bis(4-methoxyphenyl)amino}stilbene (1) , which is narrow and asymmetric and exhibits only weak solvatochromism, indicates that 1(supper +) is a class-III or classII/III borderline mixed-valence(MV) species. The narrowness, asymmetry, and solvatochromism of the IVCT band of the 4,4'-bis(di-p-anisylamino)stilbene MV cation, (E)-4,4'-Bis{bis(4-methoxyphenyl)amino}stilbene(super +), indicates that this species falls into a similar regime of delocaliztion as bis(diarylamino)biphenyl cations.

Sonogashira coupling is used for preparing a chromophore in which zinc porphyrin donors are linked through their meso positions by ethynyl bridges to a bis(indolinylidenemethyl) squaraine core. The chromophore has displayed a two-photon absorption spectrum characterized by a peak cross section of 11000 GM and has also displayed a large cross section of >780 GM over a photon-wavelength window.

Stable extended bis(donor) squaraines that show extremely large [delta] at photon wavelengths of 1 [mu]m were synthesized. It was seen that a large third-order susceptibility and significant two-photon absorption were demonstrated in a film at telecommunication wavelengths.

A study is conducted which shows that extended D-A-D oligophenylenevinylenes show large two-photon absorption (TPA) cross sections in a wide wavelength range and peak cross sections up to 5300 GM. The findings indicate that relatively small changes in molecular structure can lead to large effects on the optical properties in this class material.

Efficient single-photon and multiphoton induced fluorescence resonance energy transfer (FRET) between donor two-photon absorbing chromophore (TPAC) moieties and a nile red acceptor chromophore in the novel dendrimers is demonstrated. A synthesis of these dendritic energy-harvesting systems and the results of the relevant absorption, single-photon, and multiphoton fluorescence experiments are detailed.

Study is presented to show that chromophore-metal particle assembly has impressive two-photon properties, and the level of interaction between chromophores may be related to formation of specific geometric domains on the metal surface. The evidence for ultrafast energy migration is seen in this chromophore shell-metal nanoparticles system, which is of potential interest for light harvesting and sensing applications.

A novel bichromophoric system that is capable of undergoing efficient fluorescence resonance energy transfer (FRET) following either two-photon or single photon excitation is presented. The bichronophoric system uses FRET to show that it is possible to utilize high-intensity infrared light to activate molecules.

Direct Methanol Fuel Cell (DMFC) is a promising power source for continuous generation of energy without evolution of any toxic by-products and greenhouse gases. Pt-Ru has been the accepted gold standard anode electro-catalyst for DMFC, but significant advances are required to enhance its performance and stability. A complexed sol-gel (CSG) approach has been used to develop nanostructured powder materials. Herein we report a novel CSG process to synthesize nanoparticulate high specific surface area (HSA), completely unsupported Pt(Ru) based electro-catalyst exhibiting three fold higher electrochemically active surface area (ECSA) and ultra high electrochemical performance compared to commercially available Johnson Matthey Pt-Ru black catalyst, the currently accepted gold standard. Furthermore, in identical single full cell DMFC configuration tests for methanol oxidation, current and power densities ~40% higher than that displayed by Johnson Matthey catalyst is achieved. [ABSTRACT FROM AUTHOR]

Nanostructured powder catalysts comprising solid solutions of F doped SnO2 and IrO2 of different compositions were synthesized by a simple two step approach. High surface area SnO2:F was prepared initially using CTAB as a surfactant. (Ir,Sn)O2:F was then synthesized by forming a solid state solution with IrCl4 and SnO2:F followed by heat-treatment in air at 400°C. The catalyst was then coated onto a porous Ti foil and has been studied as a promising anode electro-catalyst for oxygen evolution reaction (OER) in PEM based water electrolysis. The optimal composition of (Ir0.3Sn0.7)O2:10 wt% F displayed electrochemical activity comparable to the commercially available pure IrO2 demonstrating ~70 mol% reduction in noble metal content. The electrochemical stability tests also showed that (Ir,Sn)O2:F solid solution exhibits much better durability compared to commercial IrO2, the standard (OER) catalyst. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the factors affecting the bone union time and the occurrence of nonunion after intramedullary nailing of subtrochanteric femoral fractures in adults. Materials and Methods: We retrospectively reviewed data from 31 patients (22 men and 9 women) who had undergone femoral intramedullary nailing at least 1 year post-operatively and analyzed the bone union time, nonunion rates, and factors that affected the bone union time according to the fracture classification (AO and Fielding classifications), comminution of the medial cortex, reduction method, and additional cerclage wiring. Results: The average union time was 26.4 weeks. There were no differences in the bone union time according to the fracture classification, reduction method, or additional cerclage wiring. Significant differences were found in the bone union time between the medial cortex comminution and non-comminution groups. A relatively strong positive correlation was detected between the degree of post-operative displacement and the bone union time. Nonunion occurred in three cases and there was no failure of implants. Conclusion: The bone union time was not affected by the reduction method nor additional cerclage wiring in intramedullary nailing of subtrochanteric femur fractures. Comminution of the medial cortex and the degree of the postoperative displacement of fractures contributed to the delayed time of union. [ABSTRACT FROM AUTHOR]

Nanocrystalline vanadium nitride (VN) has been synthesized using a simple two-step procedure involving mechano-chemical reaction of V2O3 and Li3N mixture induced by high energy mechanical milling (HEMM) followed by washing in water. The crystalline VN thus synthesized has been analyzed as a supercapacitor material in aqueous media. The electrochemical mechanism and material properties influencing the supercapacitor behavior of VN have been explored. The surface properties of the nanocrystalline VN have also been studied using X-ray photo-electron spectroscopy (XPS) and correlated to the electrochemical response. Stable capacitances of upto 60 F/g are reported here for nanocrystalline VN generated using the high energy mechano-chemical reaction method. Cycling induced degradation of capacitance has also been studied and the possible degradation mechanisms have been discussed. [ABSTRACT FROM AUTHOR]

This article presents a method of analyzing how drivers' anthropometric data are best accommodated by a specific driver-vehicle interface. Three-dimensional (3-D) manikins with 18 links were developed using anthropometric data for the U.S. 95th percentile male and 5th percentile female. In addition, an adjustable seating buck was constructed to control 7 package variables. After the manikins were positioned in each driving environment, 3-D Cartesian coordinates for the manikins' articulations were determined using a coordinate measuring machine. The data were then converted into joint angles to suggest suitable driving environments that consider appropriate driving postures. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 269–284, 2004. [ABSTRACT FROM AUTHOR]

Nanophotonics defined as nanoscale optical science and technology is a new frontier, which includes nanoscale confinement of radiation, nanoscale confinement of matter, and nanoscale photophysical or photochemical transformation. Selected examples of our research work in each of these areas are presented here. Nonlinear optical interactions involving nanoscale confinement of radiation is both theoretically and experimentally studied using a near-field geometry. The effort in nanoscale confinement of optical domains is focused to control excitation dynamics and energy transfer as well as to produce photon localization using nanostructured materials, rare-earth work on doped glasses and novel inorganic-oganic photorefractive nanocomposites are presented. Spatially localized photochemistry using a near-field two-photon excitation is being developed for nanofabrication and nanoscale memory. [ABSTRACT FROM AUTHOR]

Nanocrystalline NaMn2O4 with a crystallite size of ~8-10 nm exhibiting a new close packed hexagonal crystalline form, different from the known stable orthorhombic (Pbam or Pmnm symmetry) or monoclinic structures common to the Na–Mn–O system, has been synthesized by a high energy mechano-chemical milling process (HEMM) using Na2O2 and Mn2O3 as starting materials. The newly synthesized structure of NaMn2O4 has been studied as a cathode for sodium ion rechargeable batteries. The HEMM derived NaMn2O4 shows a 1st cycle discharge capacity ~75 mAh/g, ~86 mAh/g and ~95 mAh/g when cycled at a rate of ~40 mA/g in the potential window ∼2.0-4.0 V, ~2-4.2 V and ~2-4.5 V, respectively. The nanostructured NaMn2O4 shows a fade in capacity of 0.3% per cycle and a moderate rate capability when cycled in the potential window 2-4 V. However, electrolyte decomposition occurring during charging of the electrode above ~3.8 V needs to be resolved in order utilize the full capacity of NaMn2O4 as well as improve the stability of the electrode. [ABSTRACT FROM AUTHOR]