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81.
82.
Tadahiro Ohshima Yoshihisa Kogami Takashi Miyata Tadashi Uragami 《Journal of membrane science》2005,260(1-2):156-163
The permeation and separation characteristics of volatile organic compounds (VOCs), such as chloroform, benzene, and toluene, from water by pervaporation through cross-linked poly(dimethylsiloxane) membranes prepared from poly(dimethylsiloxane) dimethylmethacrylate macromonomer (PDMSDMMA) and divinyl compounds, such as ethylene glycol dimethylmethacrylate (EGDM), divinyl benzene (DVB), divinyl siloxane (DVS), and divinyl perfluoro-n-hexane (DVF) are described. When aqueous solutions containing 0.05 wt.% VOCs were permeated through cross-linked PDMSDMMA membranes, these membranes showed high VOC/water selectivity and permeability. Both VOC/water selectivity and permeability were affected significantly by the divinyl compound. Furthermore cross-linked PDMSDMMA membranes showed the highest chloroform/water selectivity. The VOC/water selectivity was mainly governed by the sorption selectivity rather than the diffusion selectivity. However, the difference in the selectivity between different types of VOCs depended on differences in the diffusivity of permeants. With increasing downstream pressure, the VOC/water selectivity of all cross-linked PDMSDMMA membranes increased, but the permeability decreased. A PDMSDMMA–DVF membrane exhibited a normalized permeation rate of 1.9 × 10−5 kg m/m2 h and a separation factor for chloroform/water of 4850, yielding a separation index of 9110. The pervaporation characteristics of the cross-linked PDMSDMMA membranes are discussed based on their chemical and physical structures as well as the chemical and physical properties of the permeants. 相似文献
83.
Visible‐Light‐Induced Electron Transport from Small to Large Nanoparticles in Bimodal Gold Nanoparticle‐Loaded Titanium(IV) Oxide 下载免费PDF全文
Dr. Shin‐ichi Naya Tadahiro Niwa Takahiro Kume Prof. Dr. Hiroaki Tada 《Angewandte Chemie (International ed. in English)》2014,53(28):7305-7309
A key to realizing the sustainable society is to develop highly active photocatalysts for selective organic synthesis effectively using sunlight as the energy source. Recently, metal‐oxide‐supported gold nanoparticles (NPs) have emerged as a new type of visible‐light photocatalysts driven by the excitation of localized surface plasmon resonance of Au NPs. Here we show that visible‐light irradiation (λ>430 nm) of TiO2‐supported Au NPs with a bimodal size distribution (BM‐Au/TiO2) gives rise to the long‐range (>40 nm) electron transport from about 14 small (ca. 2 nm) Au NPs to one large (ca. 9 nm) Au NP through the conduction band of TiO2. As a result of the enhancement of charge separation, BM‐Au/TiO2 exhibits a high level of visible‐light activity for the one‐step synthesis of azobenzenes from nitrobenzenes at 25 °C with a yield greater than 95 % and a selectivity greater than 99 %, whereas unimodal Au/TiO2 (UM‐Au/TiO2) is photocatalytically inactive. 相似文献
84.
Abstract 1, 2, 3-Tri-O-acetyl-6-O-benzyl-4-O-chloroacetyl-α- and -β-D-glucopyranose (4α β)were derived from 1, 2, 3-tri-O-acetyl-4, 6- O -benzyl-idehe-β-D-giucopyranose (1) in two steps. Compound 1, 1, 2, 3-tri-O -acetyl-β-D-glucopyranose (2), and 4α,β were subjected to the cyclization reaction using Lewis acids ( SnCl4 and BF3-etherate), to give corresponding 1, 6-anhydro derivatives. 相似文献
85.
Oxo-Centered mixed-valence trinuclear Iron butyrates, [Fe3O(C3H7CO2)6(py)3]·x(py); x=0, 1, were newly synthesized and their Mössbauer spectra were determined. The temperature dependent mixed-valence state was observed in both the pyridine-solvated and the non-solvated complexes. 相似文献
86.
87.
We study the local-in-time regularity of the Brownian motion with respect to localized variants of modulation spaces and Wiener amalgam spaces . We show that the periodic Brownian motion belongs locally in time to and for (s−1)q<−1, and the condition on the indices is optimal. Moreover, with the Wiener measure μ on T, we show that and form abstract Wiener spaces for the same range of indices, yielding large deviation estimates. We also establish the endpoint regularity of the periodic Brownian motion with respect to a Besov-type space . Specifically, we prove that the Brownian motion belongs to for (s−1)p=−1, and it obeys a large deviation estimate. Finally, we revisit the regularity of Brownian motion on usual local Besov spaces , and indicate the endpoint large deviation estimates. 相似文献
88.
We implement an infinite iteration scheme of Poincaré-Dulac normal form reductions to establish an energy estimate on the one-dimensional cubic nonlinear Schrödinger equation (NLS) in ${C_tL^2(\mathbb{T})}$ C t L 2 ( T ) , without using any auxiliary function space. This allows us to construct weak solutions of NLS in ${C_tL^2(\mathbb{T})}$ C t L 2 ( T ) with initial data in ${L^2(\mathbb{T})}$ L 2 ( T ) as limits of classical solutions. As a consequence of our construction, we also prove unconditional well-posedness of NLS in ${H^s(\mathbb{T})}$ H s ( T ) for ${s \geq \frac{1}{6}}$ s ≥ 1 6 . 相似文献
89.
Commutators of bilinear pseudodifferential operators with symbols in the Hörmander class $BS_{1, 0}^{1}$ and multiplication by Lipschitz functions are shown to be bilinear Calderón-Zygmund operators. A connection with a notion of compactness in the bilinear setting for the iteration of the commutators is also made. 相似文献
90.
Two new pentacyclic indole alkaloids, lirofolines A and B, possessing a novel rearranged ibogan ring system, are obtained from two Malayan Tabernaemontana species (Tabernaemontana corymbosa and Tabernaemontana divaricata) and the structures are established by analysis of the spectroscopic data. A biomimetic partial synthesis of lirofoline A from ibogaine via the Polonovski reaction is carried out. Lirofolines A and B showed significant activity in reversing multidrug resistance in vincristine-resistant KB cells (IC50 3.4 and 7.5 μg/ml, respectively). 相似文献