Search results for "Symbol"

Raman measurements in the intermediate phase of [N(CH3)4]2ZnI4

1991

Abstract Raman spectra and deviation angle of the indicatrix have been measured in the intermediate phase, between the two transition temperatures T c1 = 255 K and T c2 = 217 K. The results are consistent with the existence, in this phase, of large domains, piled up along the c-axis (Pnma notation).

1993

The formulation of the synthetic theory represented a significant-advance for evolutionary studies, which had previously been hampered by apparently irreconcilable contractions. Combining Mendelian laws with Darwinism, it joined the antitheses in a synthesis which was subsequently refined and completed. Today, its content may not be simply rejected or ignored, although there are those who think of it as little more than a corpse.

On the spectrum of semi-classical Witten-Laplacians and Schrödinger operators in large dimension

2005

We investigate the low-lying spectrum of Witten–Laplacians on forms of arbitrary degree in the semi-classical limit and uniformly in the space dimension. We show that under suitable assumptions implying that the phase function has a unique local minimum one obtains a number of clusters of discrete eigenvalues at the bottom of the spectrum. Moreover, we are able to count the number of eigenvalues in each cluster. We apply our results to certain sequences of Schrodinger operators having strictly convex potentials and show that some well-known results of semi-classical analysis hold also uniformly in the dimension.

Excitation Energy-Transfer in the LH2 Antenna of Photosynthetic Purple Bacteria via Excitonic B800 and B850 States

2000

A newly developed CIEM method that uses a combination of semi-empirical or ab-initio configuration interaction methods and exciton theory to predict electronic energies, eigenstates, absorption and CD spectra of aggregated chromophoric systems with environmental interactions included is extended and used for estimation of excitation energy transfer rates. Excitonic energy levels of the two ring systems the B800 and the B850 of the light harvesting antenna LH2 of Rhodopseudomonas acidophila and the corresponding absorption spectrum were calculated by assuming inter-ring interactions to be zero. Excitation energy transfer rates were calculated by using the Fermi Golden rule with the dipole - …

Openness and Discreteness

2013

The aim of this chapter is to study conditions under which a mapping of finite distortion is open (maps open sets to open sets) and discrete (preimage of each point is a discrete set).

Poincare Inequalities and Spectral Gap, Concentration Phenomenon for G-Measures

2002

We produce a new approach based upon inequalities of Poincare’s type for giving constructive estimates of the mixing rate for a family of mixing stationary processes continuously depending on their past called g-measures. We establish also exponential inequalities of Hoeffding’s type leading to a concentration phenomenon for a large class of observables; this last property permits in particular to give the typical behaviour of the n-orbits of a g-measure.

Saddle index properties, singular topology, and its relation to thermodynamic singularities for aϕ4mean-field model

2004

We investigate the potential energy surface of a ${\ensuremath{\phi}}^{4}$ model with infinite range interactions. All stationary points can be uniquely characterized by three real numbers ${\ensuremath{\alpha}}_{+},{\ensuremath{\alpha}}_{0},{\ensuremath{\alpha}}_{\ensuremath{-}}$ with ${\ensuremath{\alpha}}_{+}+{\ensuremath{\alpha}}_{0}+{\ensuremath{\alpha}}_{\ensuremath{-}}=1$, provided that the interaction strength $\ensuremath{\mu}$ is smaller than a critical value. The saddle index ${n}_{s}$ is equal to ${\ensuremath{\alpha}}_{0}$ and its distribution function has a maximum at ${n}_{s}^{\mathrm{max}}=1∕3$. The density $p(e)$ of stationary points with energy per particle $e$, as well as…

Structure and Photocatalytic Properties of TiO2-WO3Composites Prepared by Electrophoretic Deposition

2015

In this work TiO2-WO3 composite films containing different oxide concentrations were prepared by electrophoretic deposition on steel substrates. Composite coating structures were analyzed by X -ray diffraction, Raman spectra and scanning electron microscopy. The results showed an even distribution of WO3 particles in the entire composite layer. Light absorption measurements were used for photocatalytic properties evaluation. It was found that the removal ratio of methylene blue depends on the (TiO2):(WO3) concentration ratio. The most effective photodegradation was determined for the sample that was electrophoretically deposited from the suspension with the molar content ratio n(TiO2):n(WO3…

Special Functions for the Study of Economic Dynamics: The Case of the Lucas-Uzawa Model

2004

The special functions are intensively used in mathematical physics to solve differential systems. We argue that they should be most useful in economic dynamics, notably in the assessment of the transition dynamics of endogenous growth models. We illustrate our argument on the Lucas-Uzawa model, which we solve by the means of Gaussian hypergeometric functions. We show how the use of Gaussian hypergeometric functions allows for an explicit representation of the equilibrium dynamics of the variables in level. In contrast to the preexisting approaches, our method is global and does not rely on dimension reduction.

Optimisation algorithms in the case of mineral detection using Raman Analysis

2013

Abstract Raman analysis can be used to analyse the existence of minerals in an ore sample. Especially the interest here is to analyse given ore sample rapidly, to find out what minerals it contains. Rapid analysis would enable more rapid exploration of minerals as analysis could be carried out on-site. For this study, ore samples were collected from two mines in Northern Finland, Kittila and Kevitsa. An optimisation algorithm was constructed to form a linear combination of reference spectra which best represent the measured spectrum from an ore sample. The reference spectra were collected from a public source. It was found that solving for an optimal summation of reference spectra can be a …