			Home About us Contact

Parameter M (parameter + m)

Distribution by Scientific Domains

Physics and Astronomy	40%
Chemistry	40%

Selected Abstracts

Tristimulus algorithm of colour matching for precoloured fibre blends based on the Stearns,Noechel model

COLORATION TECHNOLOGY, Issue 2 2006
L I Rong
Prediction of the formula for matching a given colour standard by blending predyed fibres is of considerable importance to the textile industry. This kind of formulation lacks a computer-aided tool to assist colourists to find a good recipe to reproduce a target colour. In this study a tristimulus colour-matching algorithm based on the Stearns,Noechel model is proposed. This algorithm was run to predict recipes for 54 viscose blends. Colour differences between the original blend samples and the blend samples prepared according to the matched recipes were measured and expressed in CIELab 1976 units (D65 illuminant and 10° standard observer). Used in the classical way, in which the parameter M (the empirical constant in the Stearns,Noechel model) equals 0.09, the maximum colour difference is 2.16 CIELab units. The average computed colour difference is 0.69 CIELab units. It is demonstrated that the algorithm can be used in colour matching of fibre blends. A new method to acquire the set of M values is proposed in this study. [source]

Linking dispersal, immigration and scale in the neutral theory of biodiversity

ECOLOGY LETTERS, Issue 12 2009
Ryan A. Chisholm
Abstract In the classic spatially implicit formulation of Hubbell's neutral theory of biodiversity a local community receives immigrants from a metacommunity operating on a relatively slow timescale, and dispersal into the local community is governed by an immigration parameter m. A current problem with neutral theory is that m lacks a clear biological interpretation. Here, we derive analytical expressions that relate the immigration parameter m to the geometry of the plot defining the local community and the parameters of a dispersal kernel. Our results facilitate more rigorous and extensive tests of the neutral theory: we conduct a test of neutral theory by comparing estimates of m derived from fits to empirical species abundance distributions to those derived from dispersal kernels and find acceptable correspondence; and we generate a new prediction of neutral theory by investigating how the shapes of species abundance distributions change theoretically as the spatial scale of observation changes. We also discuss how our main analytical results can be used to assess the error in the mean-field approximations associated with spatially implicit formulations of neutral theory. Ecology Letters (2009) 12: 1385,1393 [source]

Hydrogenic impurity in two-dimensional semiconductors with anisotropic energy spectrum of carriers

LASER PHYSICS LETTERS, Issue 12 2005
S. P. Andreev
Abstract The binding energy and wave function of a ground state of a shallow hydrogenic impurity in two-dimensional semiconductors with isotropic and anisotropic effective mass of carriers m* = {m,, m,, m,} are derived. The calculations are performed by the variational method based on a two-parametric trial wave function. The dependence of binding energy and deformation of an impurity on 2D layer thickness and effective mass anisotropy parameter m,/m, is investigated. The obtained results are in a good agreement with experimental data and in the limiting cases coincide with the theoretical calculations of shallow impurity binding energy for bulk semiconductors [1] and two-dimensional semiconductors with isotropic effective mass of electrons [2]. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Role of interfaces on the direct tunneling and the inelastic tunneling behaviors through metal/alkylsilane/silicon junctions

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2006
D. K. Aswal
Abstract We studied the influence of the end group of the alkylsilane molecule used in Self Assembled Monolayer (SAM) in Silicon/SAM/Metal junctions. By Inelastic Electron Tunneling spectroscopy (IETS), we showed the formation of a covalent bond between the molecules and the gold electrode in the case of a thiol terminated alkylsilane. By electrical characterizations, we demonstrated that the thiol group at the interface avoids diffusion of gold into the molecule even for a 3 carbons chain. For this short molecule, we observed pure tunnel conduction with barrier height at the monolayer/Si and monolayer/Au interfaces found to be respectively 2.14 and 2.56 eV. These values were obtained using Simmons equation with an effective mass parameter m * = 0.16me (me = mass of the electron). This extends the demonstration of the excellent tunnel dielectric behavior of these organic monolayers down to 3 carbon atoms with a thiol/Au bond at the interface. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Curing kinetics of boron-containing phenol,formaldehyde resin formed from paraformaldehyde

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2002
Yanfang Liu
A boron-containing phenol,formaldehyde resin (BPFR) was synthesized from boric acid, phenol, and paraformaldehyde. The curing reaction of BPFR was studied by Fourier-transform infrared spectrometry and differential scanning calorimetry. According to the heat evolution behavior during the curing process, several influencing factors on isothermal curing reaction were evaluated. The results show that the isothermal kinetic reaction of BPFR follows autocatalytic kinetics mechanism, and kinetic parameters m, n, k1, and k2, were derived, respectively. In the latter reaction stage, the curing reaction becomes controlled mainly by diffusion. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 638,644, 2002 [source]