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1.
Ron Kimmel Doron Shaked Michael Elad Irwin Sobel 《IEEE transactions on image processing》2005,14(6):796-803
Gamut mapping deals with the need to adjust a color image to fit into the constrained color gamut of a given rendering medium. A typical use for this tool is the reproduction of a color image prior to its printing, such that it exploits best the given printer/medium color gamut, namely the colors the printer can produce on the given medium. Most of the classical gamut mapping methods involve a pixel-by-pixel mapping and ignore the spatial color configuration. Recently proposed spatial-dependent approaches for gamut mapping are either based on heuristic assumptions or involve a high computational cost. In this paper, we present a new variational approach for space-dependent gamut mapping. Our treatment starts with the presentation of a new measure for the problem, closely related to a recent measure proposed for Retinex. We also link our method to recent measures that attempt to couple spectral and spatial perceptual measures. It is shown that the gamut mapping problem leads to a quadratic programming formulation, guaranteed to have a unique solution if the gamut of the target device is convex. An efficient numerical solution is proposed with promising results. 相似文献
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3.
In his celebrated paper, Polya has considered the random walk in the three-dimensional (cubic) lattice and showed that the probability of return to the origin is less than 1. Subsequent authors have shown that the probability is %34.053.... Here we consider the same random walk, with the restriction that the drunkard is only allowed to stay inxyz. It is shown that his probability of returning to the originand staying in the allowed region is %6.4844.... 相似文献
4.
Using well-cycled, thin composite graphite electrodes we analyze carefully the limitations of potentiostatic and galvanostatic intermittent titration techniques (PITT and GITT, respectively) for determination of the differential (incremental) intercalation capacitance, Cdif, and the chemical diffusion coefficient, D, of Li ions in these ion-insertion electrodes (IIEs). We demonstrate the superiority of the GITT over PITT to determine these quantities as the former technique allows for a more accurate determination of Cdif and hence D which closely approach to the spinodal domain related to the first-order phase transition during ion-insertion. We show that GITT is also more effective in eliminating the parasitic contributions of background currents to the total measured response. A pronounced difference in the initial, intrinsic kinetics of formation of a new phase in the bulk of the old one has been observed depending on the direction of titration (phases less saturated with Li are formed faster during deintercalation than the Li-rich phases in the course of intercalation). 相似文献
5.
Elena Levi Eli Lancry Yossi Gofer Doron Aurbach 《Journal of Solid State Electrochemistry》2006,10(3):176-184
A crystallographic approach was applied to elucidate the influence of the nature of the surface films on the electrochemical
behavior of Li and Mg intercalation compounds. This paper presents two examples: (1) protection of graphite electrodes by
Li2CO3 surface films, and (2) the unique electrochemical behavior of Mg-containing Chevrel phases (MgCP) obtained by different synthetic
routes. In the former case, the elucidation of the protection mechanism and the explanation of the high performance of such
protected electrodes are based on the analysis of possible Li-ion motion in the carbonate crystal structure. In the latter
case, a combination of synthesis, electrochemistry and XRD analysis was used to explain an unusual phenomenon: the difference
between the excellent electrochemical behavior of the Chevrel phase (CP) based on Cu-leached Cu2Mo6S8 (CuCP), and the poor electrochemical activity of the high-temperature synthesized MgCP, with the same phase composition.
It is shown that this phenomenon is caused by MgO formation on the surface of the latter material. The different surface chemistry
of the MgCPs obtained by the two different synthetic routes was substantiated by revealing the correlation between the electrochemical
activity and the chemical stability of these materials under ambient atmosphere conditions.
Dedicated to Prof. Mikhail A. Vorotyntsev on the occasion of his 60th birthday. 相似文献
6.
E. Lancry E. Levi A. Mitelman S. Malovany D. Aurbach 《Journal of solid state chemistry》2006,179(6):1879-1882
The Chevrel phase (CP), Mo6S8, was found to be an excellent cathode material for rechargeable magnesium batteries. Mo6S8 is obtained by a leaching process of Cu2Mo6S8, which removes the copper. A new method of Cu2Mo6S8 production was developed. In contrast to the well-known solid-state synthesis of CP, the method is based on the reaction in a molten salt media (KCl). A fast kinetics of this reaction allows using less active, but more convenient precursors (sulfides instead of sulfur), decreasing temperature and synthesis duration, as well as operation in the inert atmosphere instead of dynamic evacuated systems. It was shown that the composition and the electrochemical behavior of the products obtained by MSS and by the solid-state synthesis are identical. Thus, the molten salt method is extremely attractive for the large-scale production of the active materials for Mg batteries. 相似文献
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8.
Iris Binyamin Eitan Grossman Matanel Gorodnitsky Doron Kam Shlomo Magdassi 《Advanced functional materials》2023,33(24):2214368
High-performance polymers are an important class of materials that are used in challenging conditions, such as in aerospace applications. Until now, 3D printing based on stereolithography processes can not be performed due to a lack of suitable materials. There is report on new materials and printing compositions that enable 3D printing of objects having extremely high thermal resistance, with Tg of 283 °C and excellent mechanical properties. The printing is performed by a low-cost Digital Light Processing printer, and the formulation is based on a dual-cure mechanism, photo, and thermal process. The main components are a molecule that has both epoxy and acrylate groups, alkylated melamine that enables a high degree of crosslinking, and a soluble precursor of silica. The resulting objects are made of hybrid materials, in which the silicon is present in the polymeric backbone and partly as silica enforcement particles. 相似文献
9.
Electrochemical impedance spectroscopy is used to characterize thin p-doped polypyrrole (PPy) films in propylene carbonate (PC) solutions and poly(trifluorophenyl)thiophene (PTFPT), in solutions based on sulfolane (SF). It appears that the latter film is much less swelled compared to the former one. One consequence of this difference is that the PTFPT film shows a much higher bulk resistance compared to that for the PPy film. Another important consequence is that the swelling of the PTFPT film is essentially physically non-homogeneous. Two parallel, uncoupled paths, with different chemical diffusion coefficients, model the experimental results adequately. In order to quantify the impedance spectra for both polymer films, we use a model proposed by Rubinstein et al. explaining the difference in the diffusion coefficients of Ru(bpy)3+/2+
3 within a thin Nafion film. The model can also predict the impedance spectra for composite powdery electrodes containing different particle sizes, such as composite cathodes and graphite anodes used in lithium batteries. 相似文献
10.
For pt.I see ibid. vol.42, no.10, p.2549, 1994. We present several novel algorithms for array processing, as well as extensions of existing methods based on this approach. We first consider the problem of localization of wideband sources via coherent processing, and show how wavefield modeling enables us to derive expressions for the frequency transformation (focusing) matrices. This method is extended to three dimensions and to sector processing. We then develop computationally efficient implementations of MUSIC and Root-MUSIC for the narrowband and the coherent and incoherent wideband cases, as well as a natural extension of Root-MUSIC to any 2-D array. In addition, wavefield modeling allows us for the first time to extend Root-MUSIC to 3-D arrays and wavefields. We also present a low complexity variant of Root-MUSIC for direction finding within a limited angular sector. Finally, we derive a low-dimensional sufficient statistic and reduced rank processing schemes for the case of oversampled arrays and/or limited angular sector scenarios 相似文献