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Enhancement Mechanism (enhancement + mechanism)

Distribution by Scientific Domains
Polymers and Materials Science40%
Chemistry40%

Selected Abstracts

Conductance Enhancement Mechanisms of Printable Nanoparticulate Indium Tin Oxide (ITO) Layers for Application in Organic Electronic Devices,

ADVANCED ENGINEERING MATERIALS, Issue 4 2009
Michael Gross
We present and discuss several methods to enhance the electrical properties of nanoparticle dispersion derived ITO-layers. A maximum conductance of 132,,,1,cm,1 was achieved and films with a sheet resistance down to 5,,/, were produced. To demonstrate their applicability as electrodes in optoelectronic elements we assembled functioning polymer LED-s on them. [source]

Surface-enhanced Raman spectroscopy with ultraviolet excitation

JOURNAL OF RAMAN SPECTROSCOPY, Issue 6-7 2005
Xu-Feng Lin
Abstract Surface-enhanced Raman scattering (SERS) spectroscopy excited with a UV laser was successfully developed and the UV,SER spectra of various adsorbates, including pyridine and SCN,, on different transition metal electrodes were obtained. The experimental requirements for obtaining UV,SERS in an electrochemical system are given. The surface enhancement factor of a roughened Rh electrode covered with thiocyanate as a model molecule was estimated to be about two orders of magnitude in the UV region, consistent with our preliminary theoretical calculation based on the electromagnetic model. The investigation of SERS in the UV region will improve the understanding of the SERS enhancement mechanism and broaden the research field of SERS in areas such as surface science and the life sciences. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Luminol chemiluminescence catalysed by colloidal platinum nanoparticles

LUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 2 2007
Sheng-Liang Xu
Abstract Platinum colloids prepared by the reduction of hexachloroplatinic acid with citrate in the presence of different stabilizers were found to enhance the chemiluminescence (CL) of the luminol,H2O2 system, and the most intensive CL signals were obtained with citrate-protected Pt colloids synthesized with citrate as both a reductant and a stabilizer. Light emission was intense and reproducible. Transmission electron microscopy and X-ray photoelectron spectroscopy studies were conducted before and after the CL reaction to investigate the possible CL enhancement mechanism. It is suggested that this CL enhancement is attributed to the catalysis of platinum nanoparticles, which could accelerate the electron-transfer process and facilitate the CL radical generation in aqueous solution. The effects of Pt colloids prepared by the hydroborate reduction were also investigated. The application of the luminol,H2O2,Pt colloids system was exploited for the determination of compounds such as uric acid, ascorbic acid, phenols and amino acids. Copyright © 2006 John Wiley & Sons, Ltd. [source]

The characterisation of orographic rainfall

METEOROLOGICAL APPLICATIONS, Issue 2 2000
W R Gray
The Otaki Precipitation Estimation by Radar (OPERA) programme was designed to investigate the processes that lead to enhancement of rainfall over the Tararua ranges of New Zealand. These ranges rise to 1500 m above the coastal plain and enhancement of rainfall by windflow over these hills leads to annual hill-top rainfall of over four times that upwind. The OPERA experimental campaigns aimed to characterise the enhancement processes by analysing data collected from a transect of high-resolution rain gauges and a locally deployed, high-resolution radar, supported by scanning radar and satellite observations. Measurements made during these experiments showed that orographic enhancement led to hill-top accumulations often twice that upwind, and up to as much as a factor of seven in one case. The data suggest that the most frequent occurring enhancement mechanism was triggered convection. This mechanism leads to an increase in rainfall over the hills of around a factor of two, primarily through an increase in the duration of rain. Seeder/feeder-type enhancement occurs less frequently but leads to larger enhancements. Copyright © 2000 Royal Meteorological Society [source]

Enhanced Crystallinity of PTFE by Ion Irradiation in a Dense Plasma Focus

PLASMA PROCESSES AND POLYMERS, Issue 2 2007
Mehboob Sadiq
Abstract Nitrogen-ion beam pulses emitted from a low-energy (1.45 kJ) Mather-type plasma focus device are used for the surface modification of PTFE polymer specimens. The specimens, placed at a fixed position, are implanted using different number of pulses. Raman spectroscopy and XRD are employed to probe the structural changes incurred during the ion implantation. Both techniques indicate that the crystalline order in the specimens increases with increasing the irradiation dose. The crystallinity degree of the irradiated specimens, as measured from the XRD data, is found to enhance monotonically from 40% to about 55%. Possible crystallinity enhancement mechanism of irradiated PTFE specimens via chain scission is discussed. [source]