Presented is a new version of logarithmic transform for image enhancement: fused logarithmic transform (fLog). Based on multi-resolution spline fusion technology, a composite image with a significant improvement in im...
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Presented is a new version of logarithmic transform for image enhancement: fused logarithmic transform (fLog). Based on multi-resolution spline fusion technology, a composite image with a significant improvement in image contrast can be synthesised by fusing the source image and its logarithmic version. Cascaded with other image enhancement techniques, such as histogram equalisation, the fused logarithmic transform could turn the enhanced contrast into more visible details.
A modified CRAZED sequence with selective inversion before excitation was designed to investigate the longitudinal relaxation under the effects of slow chemical exchange and distant dipolar interactions in highly pola...
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A modified CRAZED sequence with selective inversion before excitation was designed to investigate the longitudinal relaxation under the effects of slow chemical exchange and distant dipolar interactions in highly polarized spin systems. Analytical expressions for the apparent longitudinal relaxation time of such systems were derived from a combination of the dipolar field theory and product operator formalism. The result shows that the signal intensity follows a multi-exponential function of the inversion recovery time. Experimental results support the theoretical predictions. (C) 2007 Elsevier B.V. All rights reserved.
Responds to comments on the use of the Kozeny-Carman equation to predict the hydraulic conductivity of soils. Urilization of air permeability tests in the chemical industry; Definition of the hydraulic mean radius; Ar...
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Responds to comments on the use of the Kozeny-Carman equation to predict the hydraulic conductivity of soils. Urilization of air permeability tests in the chemical industry; Definition of the hydraulic mean radius; Arguments of the logarithmic functions in the equation.
Dynamic logarithmic gain and its modifications can be theoretically used as a bottleneck ranking (BR) indicator in a metabolic reaction system. However, it is not sufficiently explicit whether they can be successfully...
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Dynamic logarithmic gain and its modifications can be theoretically used as a bottleneck ranking (BR) indicator in a metabolic reaction system. However, it is not sufficiently explicit whether they can be successfully used in practical applications. The present work therefore focuses on the selection of best BR indicators in both instantaneous and overall cases. A modified ethanol fermentation model is used as a case study. The results indicate that the mathematical product of dynamic logarithmic gain and desired product concentration at a given time is the best instantaneous BR indicator, whereas its value at the end time of the fermentation process is the best overall BR indicator. The former is useful for observing the time course of the desired product concentration and determining a process time to be terminated. The latter is for ranking bottleneck enzymes to determine which enzyme activity should be changed to attain a higher desired product concentration. Moreover, discussion is made on the utilization of the overall BR indicators to predict how much the final desired product concentration is increased.
it is shown that the logarithmic derivative of the characteristic polynomial of a Wilson loop in two-dimensional pure Yang Mills theory with gauge group SU(N) exactly satisfies Burgers' equation, with viscosity gi...
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it is shown that the logarithmic derivative of the characteristic polynomial of a Wilson loop in two-dimensional pure Yang Mills theory with gauge group SU(N) exactly satisfies Burgers' equation, with viscosity given by 1/(2N). The Wilson loop does not intersect itself and Euclidean space-time is assumed flat and infinite. This result provides a precise framework in 2D YM for recent observations of Blaizot and Nowak and was inspired by their work. (c) 2008 Elsevier B.V. All rights reserved.
A reduced Keller-Segel equation (RKSE) is a parabolic-elliptic system of partial differential equations which describes bacterial aggregation and the collapse of a self-gravitating gas of Brownian particles. We consid...
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A reduced Keller-Segel equation (RKSE) is a parabolic-elliptic system of partial differential equations which describes bacterial aggregation and the collapse of a self-gravitating gas of Brownian particles. We consider RKSE in two dimensions, where solution has a critical collapse (blow-up) if the total number of bacteria exceeds a critical value. We study the self-similar solutions of RKSE near the blow-up point. Near the collapse time, t = tc, the critical collapse is characterized by the L. (tc -t) 1/2 scaling law with logarithmic modification, whereLis the spatial width of the collapsing solution. We develop an asymptotic perturbation theory for these modifications and show that the resulting scaling agrees well with numerical simulations. The quantitative comparison of the theory and simulations requires several terms of the perturbation series to be taken into account.
We consider perturbations of the semiclassical Schrodinger equation on a compact Riemannian surface with constant negative curvature and without boundary. We show that, for scales of times which are logarithmic in the...
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We consider perturbations of the semiclassical Schrodinger equation on a compact Riemannian surface with constant negative curvature and without boundary. We show that, for scales of times which are logarithmic in the size of the perturbation, the solutions associated to initial data in a small spectral window become equidistributed in the semiclassical limit. As an application of our method, we also derive some properties of the quantum Loschmidt echo below and beyond the Ehrenfest time for initial data in a small spectral window.
We show that SL(2;C)/SU(2) model which had been recently proposed to describe the behavior of the local densities of states at the plateau transition in integer quantum Hall effect, has logarithmic operators. Their un...
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We show that SL(2;C)/SU(2) model which had been recently proposed to describe the behavior of the local densities of states at the plateau transition in integer quantum Hall effect, has logarithmic operators. Their unusual properties are studied in this letter.
We state some simple properties of a configuration of N bodies whose masses are not all equal, and whose motion is a 'choreography'. In such a solution of Newton's equations, the bodies chase each other ar...
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We state some simple properties of a configuration of N bodies whose masses are not all equal, and whose motion is a 'choreography'. In such a solution of Newton's equations, the bodies chase each other around the same curve, with the same phase shift between consecutive bodies. It follows from those properties that for any dimension of space, the masses of a choreography are the same for a logarithmic potential. A similar argument shows that the vorticities of a choreography are the same for N vortices which satisfy Helmholtz's equations (Philos. Mag. 33 (1858) 485-512). We prove a more general result for any potential. In particular, for a choreography with distinct masses, the ratio between the smallest and the largest mutual distances is bounded by a constant which does not depend on the masses. (C) 2003 Academie des sciences. Publie par Elsevier SAS. Tous droits reserves.
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