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731.
A method is proposed for visualizing simply the concentrations of melanin, oxygenated blood, and deoxygenated blood in skin tissue using digital RGB images. The total blood concentration and oxygen saturation can also be reconstructed. Monte Carlo simulation of light transport specifies a relation between the chromophore concentrations and Commission Internationale de l'Eclairage XYZ, which are compatible with the common RGB working space. Experiments with a tissuelike agar gel phantom demonstrated the possibility of the method. In vivo imaging of a human hand during forearm occlusion demonstrated the ability of the method to evaluate hemodynamics of skin tissue. 相似文献
732.
Thermal conductivity of glass is one of the fundamental properties of it. However, that has not been studied enough. That of only less than 20 compositions has been measured below the room temperature. In this study, we measured the thermal conductivity of xNa2O · (100 ? x)SiO2 and (33 ? y)Na2O · yCs2O · 67SiO2 glasses by a transient heating method in the temperature range from about 150 K to room temperature. The conductivity of xNa2O · (100 ? x)SiO2 is found to decrease with the increase in alkali content. The dominant factor of this behavior is the decrease in phonon mean free path, which is due to the increase of non-bridge oxygen. Thermal conductivity of (33 ? y)Cs2O · yNa2O · 67SiO2 is decreased with the increase in Cs2O/(Na2O + Cs2O) ratio. The dominant factor of this behavior is the decrease of sound velocity. However, composition dependence of the phonon mean free path also affects the thermal conductivity. Phonon mean free path of 33Cs2O · 67SiO2 glass is longer than that of 33Na2O · 67SiO2 glass, and should be related to the change in distribution of structural unit in glass. In addition, phonon mean free path of mixed alkali glasses are shorter than that of single alkali glasses. 相似文献
733.
Lu Tongbu Yang Guang Ji Liangnian Inoue Yoshihisa Ouchi Mikio Yu Kaibei 《Transition Metal Chemistry》1999,24(4):375-379
Complexes of cobalt(II) perchlorate with 16-crown-5 (L1) and its two lariat derivatives, 15,15-dimethyl-16-crown-5 (L2) and 15-(2,5-dioxahexyl)-15-methyl-16-crown-5 (L3), have been prepared and characterized. The crystal structure of [Co(L3)H2O)](ClO4)_2 has been determined by X-ray crystallography. The cobalt(II) ion is heptacoordinated with five crown ether oxygen atoms at the equatorial plane, a side arm oxygen atom and a water molecule at the apical position. The coordination polyhedron of cobalt is a distorted pentagonal bipyramid with the average Co-O(crown) distance of 2.20(2)Å. 相似文献
734.
Yasuhiko Suzuki Yoshihisa Inoue Hidetsugu Tanaka Terunori Fujita 《Macromolecular rapid communications》2004,25(3):493-497
Summary: Bis(phenoxy–ether) Ti complexes were investigated as ethylene polymerization catalysts. The complexes, combined with iBu3Al/Ph3CB(C6F5)4 or methylaluminoxane (MAO) cocatalysts, can be highly active single‐site catalysts, which display activities ( turnover frequency, max. 2 065 min−1) comparable with that of a highly active bis(phenoxy–imine) Ti complex/MAO system, and provide very high molecular weight polyethylenes ( 2 040 000–5 420 000) at 25 °C under atmospheric pressure.
735.
New ethanediyl-bridged unsymmetrical mono- and heterometallated dimers of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin (H2oep) containing transition-metal ions (Mn and Fe) were synthesized by a facile stepwise metallation/demetallation process under mild conditions. The novel metallation strategy initially involved the predominant insertion of Zn into one of the two porphyrin rings of the free-base dimer, followed by the incorporation of Mn or Fe into the other porphyrin ring under exceptionally mild conditions, giving corresponding heterometallic dimers; the subsequent removal of Zn yielded mono-transition-metal dimers. The emission spectrum of the monozinc dimer predominantly exhibited fluorescence bands of the free-base porphyrin component, indicating a very efficient energy-transfer process. Conversely, emission of the free-base or Zn porphyrin component of transition metal containing dimers was strongly quenched due to photoinduced electron transfer. 相似文献