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101.
102.
We consider the correlation functions for a hierarchical N-component classical vector model in three dimensions. For N = , we find explicitly the eigenvalues and global eigenfunctions of the linearized renormalization group transformation. In a very direct way, this yields the correlation functions for the N = model. In particular, we check that the two-point function has canonical decay. 相似文献
103.
A new and efficient conjugate addition of trialkylphosphites to 3-ω-bromoacetylcoumarin 1 catalysed by p-toluenesulfonic acid (TsOH) has been studied. Under the same conditions, an enolphosphate gave the corresponding esters of 3-acetyl-4-phosphono-2-oxochromans in high yields. The use of TsOH in the reaction of 3-acetyl-, 3-benzoyl-, and 3-ethoxycarbonyl coumarins led mainly to 1,4-addition products—the corresponding 3-acyl-4-dialkylphosphono-2-oxochromans—in very good yields. 相似文献
104.
Hematite reaction with tar to produce carbon/iron composites for the reduction of Cr(VI) contaminant
Fabiano Magalh?es Márcio César Pereira José Domingos Fabris Sue Ellen Costa Bottrel Alejandro Amaya Nestor Mogliazza Rochel Montero Lago 《Hyperfine Interactions》2010,195(1-3):43-48
In this work, highly reactive carbon–iron composites were prepared using a waste, i.e. tar, as carbon precursor and a simple iron oxide, i.e. hematite. Tar was impregnated on Fe2O3 with different tar/hematite weight ratios of 1:1; 2:1 and 4:1, and thermally treated under N2 atmosphere (400°C, 600°C and 800°C). Mössbauer, XRD and magnetization measurements suggested that treatment at 400°C and 600°C produces Fe3O4 but treatment at 800°C produced mainly Fe°. Raman and TG analyses of the different composites suggested the formation of carbon contents of 18, 24 and 32 wt.% as amorphous and graphitic highly dispersed on the Fe surface. The composites obtained at 800°C showed high efficiency to reduce Cr(VI) as CrO $_{4}^{2-}$ in aqueous medium with much better results compared to finely ground commercial Fe°. 相似文献
105.
Jeremy H Toyn Xu-Alan Lin Mark W Thompson Valerie Guss Jere E Meredith Jr Sethu Sankaranarayanan Nestor Barrezueta John Corradi Antara Majumdar Daniel L Small Melissa Hansard Thomas Lanthorn Ryan S Westphal Charles F Albright 《BMC neuroscience》2010,11(1):1-12
Background
The zebrafish visual system is a good research model because the zebrafish retina is very similar to that of humans in terms of the morphologies and functions. Studies of the retina have been facilitated by improvements in imaging techniques. In vitro techniques such as immunohistochemistry and in vivo imaging using transgenic zebrafish have been proven useful for visualizing specific subtypes of retinal cells. In contrast, in vivo imaging using organic fluorescent molecules such as fluorescent sphingolipids allows non-invasive staining and visualization of retinal cells en masse. However, these fluorescent molecules also localize to the interstitial fluid and stain whole larvae.Results
We screened fluorescent coumarin derivatives that might preferentially stain neuronal cells including retinal cells. We identified four coumarin derivatives that could be used for in vivo imaging of zebrafish retinal cells. The retinas of living zebrafish could be stained by simply immersing larvae in water containing 1 μg/ml of a coumarin derivative for 30 min. By using confocal laser scanning microscopy, the lamination of the zebrafish retina was clearly visualized. Using these coumarin derivatives, we were able to assess the development of the zebrafish retina and the morphological abnormalities induced by genetic or chemical interventions. The coumarin derivatives were also suitable for counter-staining of transgenic zebrafish expressing fluorescent proteins in specific subtypes of retinal cells.Conclusions
The coumarin derivatives identified in this study can stain zebrafish retinal cells in a relatively short time and at low concentrations, making them suitable for in vivo imaging of the zebrafish retina. Therefore, they will be useful tools in genetic and chemical screenings using zebrafish to identify genes and chemicals that may have crucial functions in the retina. 相似文献106.
Potential Analysis - Some linear integro-differential operators have old and classical representations as the Dirichlet-to-Neumann operators for linear elliptic equations, such as the 1/2-Laplacian... 相似文献
107.
Rodrigues PC Berlim LS Azevedo D Saavedra NC Prasad PN Schreiner WH Atvars TD Akcelrud L 《The journal of physical chemistry. A》2012,116(14):3681-3690
The donor-acceptor copolymer containing benzothiadiazole (electron acceptor), linked to functionalized fluorene (electron donor), [poly[9,9-bis(3'-(tert-butyl propanoate))fluorene-co-4,7-(2,1,3-benzothiadiazole)] (LaPPS40), was synthesized through the Suzuki route. The polymer was characterized by scanning electron microscopy, gel permeation chromatography, NMR, thermal analysis, cyclic voltammetry, X-ray photoelectron spectroscopy, UV-vis spectrometry, and photophysical measurements. Theoretical calculations (density functional theory and semiempirical methodologies) used to simulate the geometry of some oligomers and the dipole moments of molecular orbitals involved were in excellent agreement with experimental results. Using such data, the higher energy absorption band was attributed to the π-π* (S(0) → S(4)) transition of the fluorene units and the lower lying band was attributed to the intramolecular (ICT) (S(0) → S(1)) charge transfer between acceptor (benzothiadiazole) and donor groups (fluorene) (D-A structure). The ICT character of this band was confirmed by its solvatochromic properties using solvents with different dielectric properties, and this behavior could be well described by the Lippert-Mataga equation. To explain the solvatochromic behavior, both the magnitude and orientation of the dipole moments in the electronic ground state and in the excited state were analyzed using the theoretical data. According to these data, the change in magnitude of the dipole moments was very small for both transitions but the spatial orientation changed remarkably for the lower energy band ascribed to the ICT band. 相似文献
108.
Vanessa Menzes Martins Djalmir Nestor Messias Noelio Oliveira Dantas Antônio Medina Neto 《Journal of luminescence》2010,130(12):2491-2494
In this work, we have studied the optical and thermal properties of Nd-doped phosphate glass matrix. The studied samples have concentration ranging from 0.5 to 5 wt% of Nd2O3. Here we report the measurements of fluorescence quantum efficiency, η, obtained through the thermal lens technique using a reference sample. Also, the refractive index, n, specific heat, cp, mass density, and the thermal diffusivity and conductivity measurements were performed. The knowledge of these characteristics as a function of neodymium concentration is very important to design optical devices, especially high power solid state lasers. 相似文献
109.
Neves JL Heitmann B Reiss TO Schor HH Khaneja N Glaser SJ 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2006,181(1):126-134
The limits of polarization transfer efficiency are explored for systems consisting of three isotropically coupled spins 1/2 in the absence of relaxation. An idealized free evolution and control Hamiltonian is studied, which provides an upper limit of transfer efficiency (in terms of transfer amplitude and transfer time) for realistic homonuclear spin systems with arbitrary Heisenberg-type coupling constants J12, J13, and J23. It is shown that optimal control based pulse sequences have significantly improved transfer efficiencies compared to conventional transfer schemes. An experimental demonstration of optimal polarization transfer is given for the case of the carbon spin system of fully 13C labelled alanine at 62.5 MHz Larmor frequency. 相似文献
110.