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Full-Text Articles in Nanoscience and Nanotechnology
Leading Firms As Knowledge Gatekeepers In A Networked Environment, Deogratias Harorimana Mr
Leading Firms As Knowledge Gatekeepers In A Networked Environment, Deogratias Harorimana Mr
Dr Deogratias Harorimana
This chapter introduces the role of the knowledge gatekeeper as a mechanism by which knowledge is created and transferred in a networked environment. Knowledge creation and transfer are essential for building a knowledge based economy. The chapter considers obstacles that inhibit this process and argues that leading firms create a shared socio-cultural context that enables the condivision of tacit meanings and codification of knowledge. Leading firms act as gatekeepers of knowledge through the creation of shared virtual platforms. There will be a leading firm that connects several networks of clients and suppliers may not interact directly with one another, but …
Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala
Dielectric Relaxation Behaviour Of Glycine In Acqueous Solution Medium In The Microwave Frequency Region, Ajaya Kumar Kavala
Mr Ajaya Kumar Kavala
No abstract provided.
Quantum Transport In In0.75Ga0.25As Quantum Wires, P. J. Simmonds, F. Sfigakis, H. E. Beere, D. A. Ritchie, M. Pepper, D. Anderson, G. A.C. Jones
Quantum Transport In In0.75Ga0.25As Quantum Wires, P. J. Simmonds, F. Sfigakis, H. E. Beere, D. A. Ritchie, M. Pepper, D. Anderson, G. A.C. Jones
Paul J. Simmonds
In addition to quantized conductance plateaus at integer multiples of 2e2/h, the differential conductance G=dI/dV shows plateaus at 0.25(2e2/h) and 0.75(2e2/h) under applied source-drain bias in In0.75Ga0.25As quantum wires defined by insulated split gates. This observation is consistent with a spin-gap model for the 0.7 structure. Using a tilted magnetic field to induce Landau level crossings, the g factor was measured to be ~9 by the coincidence method. This material, with a mobility of 1.8×105 cm …
Charge Transfer Mechanisms In Electrospinning, Jonathan J. Stanger
Charge Transfer Mechanisms In Electrospinning, Jonathan J. Stanger
Jonathan J Stanger
Electrospinning is a method of producing nano structured material from a polymer solution or melt using high strength electric fields. It is a process that has yet to find extensive industrial application yet shows promise if obstacles such as low rate of production overcome perhaps by more complete theoretical modelling. This work examines the effects of adding an ionic salt to a solution of poly(vinyl alcohol) in water. The direct effect was an increase the charge density and electric current. It was found that an increase in charge density decreases the mass deposition rate and forms a thinner initial jet. …
Near-Monodisperse Ni−Cu Bimetallic Nanocrystals Of Variable Composition: Controlled Synthesis And Catalytic Activity For H2 Generation, Yawen Zhang, Wenyu Huang, Susan E. Habas, John N. Kuhn, Michael E. Grass, Yusuke Yamada, Peidong Yang, Gabor A. Somorjai
Near-Monodisperse Ni−Cu Bimetallic Nanocrystals Of Variable Composition: Controlled Synthesis And Catalytic Activity For H2 Generation, Yawen Zhang, Wenyu Huang, Susan E. Habas, John N. Kuhn, Michael E. Grass, Yusuke Yamada, Peidong Yang, Gabor A. Somorjai
Wenyu Huang
Near-monodisperse Ni1−xCux (x = 0.2−0.8) bimetallic nanocrystals were synthesized by a one-pot thermolysis approach in oleylamine/1-octadecene, using metal acetylacetonates as precursors. The nanocrystals form large-area 2D superlattices, and display a catalytic synergistic effect in the hydrolysis of NaBH4 to generate H2 at x = 0.5 in a strongly basic medium. The Ni0.5Cu0.5 nanocrystals show the lowest activation energy, and also exhibit the highest H2 generation rate at 298 K.
Structure Sensitivity Of Carbon−Nitrogen Ring Opening: Impact Of Platinum Particle Size From Below 1 To 5 Nm Upon Pyrrole Hydrogenation Product Selectivity Over Monodisperse Platinum Nanoparticles Loaded Onto Mesoporous Silica, John N. Kuhn, Wenyu Huang, Chia-Kuang Tsung, Yawen Zhang, Gabor A. Somorjai
Structure Sensitivity Of Carbon−Nitrogen Ring Opening: Impact Of Platinum Particle Size From Below 1 To 5 Nm Upon Pyrrole Hydrogenation Product Selectivity Over Monodisperse Platinum Nanoparticles Loaded Onto Mesoporous Silica, John N. Kuhn, Wenyu Huang, Chia-Kuang Tsung, Yawen Zhang, Gabor A. Somorjai
Wenyu Huang
Well-defined platinum nanoparticles between 0.8 and 5.0 nm were prepared using dendrimer and polymer capping agents and supported onto mesoporous SBA-15 silica. Using these model catalysts, pyrrole hydrogenation was demonstrated to be structure sensitive because ring opening occurred more easily over larger particles compared to smaller ones. The phenomenon is caused by surface roughness or electronic effects that change with particle size.
Dendrimer Templated Synthesis Of One Nanometer Rh And Pt Particles Supported On Mesoporous Silica: Catalytic Activity For Ethylene And Pyrrole Hydrogenation, Wenyu Huang, John N. Kuhn, Chia-Kuang Tsung, Yawen Zhang, Susan E. Habas, Peidong Yang, Gabor A. Somorrjai
Dendrimer Templated Synthesis Of One Nanometer Rh And Pt Particles Supported On Mesoporous Silica: Catalytic Activity For Ethylene And Pyrrole Hydrogenation, Wenyu Huang, John N. Kuhn, Chia-Kuang Tsung, Yawen Zhang, Susan E. Habas, Peidong Yang, Gabor A. Somorrjai
Wenyu Huang
Monodisperse rhodium (Rh) and platinum (Pt) nanoparticles as small as ∼1 nm were synthesized within a fourth generation polyaminoamide (PAMAM) dendrimer, a hyperbranched polymer, in aqueous solution and immobilized by depositing onto a high-surface-area SBA-15 mesoporous support. X-ray photoelectron spectroscopy indicated that the as-synthesized Rh and Pt nanoparticles were mostly oxidized. Catalytic activity of the SBA-15 supported Rh and Pt nanoparticles was studied with ethylene hydrogenation at 273 and 293 K in 10 torr of ethylene and 100 torr of H2 after reduction (76 torr of H2 mixed with 690 torr of He) at different temperatures. Catalysts were active without …
Highly Selective Synthesis Of Catalytically Active Monodisperse Rhodium Nanocubes, Yawen Zhang, Michael E. Grass, John N. Kuhn, Feng Tao, Susan E. Habas, Wenyu Huang, Peidong Yang, Gabor A. Somorjai
Highly Selective Synthesis Of Catalytically Active Monodisperse Rhodium Nanocubes, Yawen Zhang, Michael E. Grass, John N. Kuhn, Feng Tao, Susan E. Habas, Wenyu Huang, Peidong Yang, Gabor A. Somorjai
Wenyu Huang
Monodisperse sub-10 nm Rh nanocubes were synthesized with high selectivity (>85%) by a seedless polyol method. The {100} faces of the Rh NCs were effectively stabilized by chemically adsorbed Br− ions from trimethyl(tetradecyl)ammonium bromide (TTAB). This simple one-step polyol route can be readily applied to the preparation of Pt and Pd nanocubes. Moreover, the organic molecules of PVP and TTAB that encapsulated the Rh nanocubes did not prevent catalytic activity for pyrrole hydrogenation and CO oxidation.
Influence Of Reaction With Xef2 On Surface Adhesion Of Al And Al2o3 Surfaces, Tianfu Zhang, Jeong Park, Wenyu Huang, Gabor A. Somoraji
Influence Of Reaction With Xef2 On Surface Adhesion Of Al And Al2o3 Surfaces, Tianfu Zhang, Jeong Park, Wenyu Huang, Gabor A. Somoraji
Wenyu Huang
The change in surfaceadhesion after fluorination of Al and Al2O3surfaces using XeF2 was investigated with atomic force microscopy. The chemical interaction between XeF2 and Al and Al2O3surfaces was studied by in situx-ray photoelectron spectroscopy. Fresh Al and Al2O3surfaces were obtained by etching top silicon layers of Si∕Al and Si∕Al2O3 with XeF2. The surfaceadhesion and chemical composition were measured after the exposure to air or annealing (at 200°C under vacuum). The correlation between the adhesion force increase and presence of AlF3 on the surface was revealed.
Time-Resolved Investigation Of The Acoustic Vibration Of A Single Gold Nanoprism Pair, J. Burgin, P. Langot, N. Del Fatti, F. Vallee, Wenyu Huang, M.A. El-Sayed
Time-Resolved Investigation Of The Acoustic Vibration Of A Single Gold Nanoprism Pair, J. Burgin, P. Langot, N. Del Fatti, F. Vallee, Wenyu Huang, M.A. El-Sayed
Wenyu Huang
The acoustic vibration of single gold nanoprism pairs on a glass substrate has been investigated in the time-domain combining a spatial modulation spectroscopy microscope with a high-sensitivity femtosecond pump−probe setup. Three modes were observed and ascribed to two in-plane and one out-of-plane vibration of the nanoprisms forming the pair, in agreement with a theoretical analysis. The periods of the two former modes with similar nature show weak (about 10%) and well correlated pair to pair fluctuations that can be unambiguously ascribed to variation of the prism geometry. In contrast, strong fluctuations, by almost a factor of 6, of the mode …
Sub-Two Nanometer Single Crystal Au Nanowires, Ziyang Huo, Chia-Kuang Tsung, Wenyu Huang, Xiaofeng Zhang, Peidong Yang
Sub-Two Nanometer Single Crystal Au Nanowires, Ziyang Huo, Chia-Kuang Tsung, Wenyu Huang, Xiaofeng Zhang, Peidong Yang
Wenyu Huang
Ultrathin single crystal Au nanowires with diameter of ∼1.6 nm and length of few micrometers were synthesized with high yield by simply mixing HAuCl4 and oleylamine at room temperature. High resolution transmission electron microscopy studies revealed that all of these nanowires are single crystalline and grew along the [111] direction. The valency evolution of the gold species during the synthesis was studied by X-ray photoelectron spectroscopy, which showed a clear Au3+ → Au+ → Au stepwise reduction at different reaction stages. Small angle X-ray scattering and small-angle X-ray diffraction suggest mesostructure formation upon HAuCl4 and oleylamine mixing. The slow in …
Morphologies And Kinetics Of A Dewetting Ultrathin Solid Film, Mikhail Khenner
Morphologies And Kinetics Of A Dewetting Ultrathin Solid Film, Mikhail Khenner
Mikhail Khenner
The surface evolution model based on geometric partial differential equation is used to numerically study the kinetics of dewetting and dynamic morphologies for the localized pinhole defect in the surface of the ultrathin solid film with the strongly anisotropic surface energy. Depending on parameters such as the initial depth and width of the pinole, the strength of the attractive substrate potential and the strength of the surface energy anisotropy, the pinhole may either extend to the substrate and thus rupture the film, or evolve to the quasiequilibrium shape while the rest of the film surface undergoes phase separation into a …
Enhanced Stability Of A Dewetting Thin Liquid Film In A Single-Frequency Vibration Field, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev
Enhanced Stability Of A Dewetting Thin Liquid Film In A Single-Frequency Vibration Field, Sergey Shklyaev, Mikhail Khenner, Alexei Alabuzhev
Mikhail Khenner
Dynamics of a thin dewetting liquid film on a vertically oscillating substrate is considered. We assume moderate vibration frequency and large (compared to the mean film thickness) vibration amplitude. Using the lubrication approximation and the averaging method, we formulate the coupled sets of equations governing the pulsatile and the averaged fluid flows in the film, and then derive the nonlinear amplitude equation for the averaged film thickness. We show that there exists a window in the frequency-amplitude domain where the parametric and shear-flow instabilities of the pulsatile flow do not emerge. As a consequence, in this window the averaged description …