The adsorption and photocatalytic degradation of Ethyl methylphosphonate (EMPA) on powdery TiO2 film has experimentally investigated using attenuated total reflection-infrared Fourier transform spectroscopy (ATR-FTIR) in ambient condition. Characteristic IR frequency as P-O-C vibration mode as EtO was observed by EMPA adsorbed at the surface of TiO2. By TiO2 photocatalysis, the adsorbed EMPA was decomposed to methyl phosphonic acid and phosphoric acid. The increment of IR intensity of which is assigned to Ti–O-P-O-Ti of EMPA was accompanied with increasing the IR peak intensity assigned to MPA. About that, we suggest that the appearance of the Ti–O-P-O-Ti of EMPA by the TiO2 photocatalysis is regarded as acceleration of the hydrolysis of EMPA by the surface OH groups of TiO2. The plausible adsorption structure and the photocatalytic reaction mechanism of EMPA at the surface of TiO2 photocatalyst were elucidated.
The hydrophobic interaction of amphiphilic copolymers, which contain 2-hydroxyethyl methacrylate(HEMA) and 1vinyl-2-pyrrolidone (VPy), with Methyl Orange (MO) was compared with that of HEMA-acrylamide (AAm) copolymers to deduce the correlation between their complexation ability in a photochromic azo dye and the photoviscosity effect in aqueous copolymer/dye complex solution. On the basis of the dialysis data and fluorometric analysis it appeared that the complexation dependence on HEMA content in the copolymers was due to the hydrophobic interaction between the polymer and the dye. For a comparable HEMA content AAm copolymers bound less MO than VPy copolymers. It was confiied by photoviscosity measurements that the conformation of the complex composed of photochromic azo dye and HEMA copolymer changed reversibly in response to the photo- and thermal isomerization of the dye. In HEMA-AAm copolymer systems the photoviscosity effect was small compared with that of HEMA-VPy copolymer systems. From these results it was concluded that the complexation ability of polymers due to the hydrophobic interaction was an important factor in producing a large photoinduced conformational change in water. 相似文献
Ejected-electron spectra have been measured for collisions of He-atoms with Na+-ions, whose impact energy ranged from 1.7 to 7.0 keV. The ion impact-energy dependence of the angular-differential cross-section of the ejected electrons has been investigated for an aligned autoionizing state Na**(2p5 3s22P), which has been created by charge transfer from the He-atoms. The alignment of the autoionizing state Na**(2p5 3s22P) is discussed in relation to the scattering angles of the Na+-ions. A complete longitudinal alignment has been observed with respect to the quasimolecular axis. 相似文献
We report on the effect on performance of varying the length of the capillary during throughout in-capillary derivatization (TICD) capillary electrophoresis (CE). Performance was evaluated by on-line coupling with a sample and CE runbuffer loading device that was newly introduced for this study. The device was assembled with a low cost using two 5 mm inner diameter (ID) disposable polyethylene syringes. First, a sequence was manually formed consisting of a 200 microL run buffer solution plug, a 100 microL sample plug and another 200 microL run buffer solution plug. Each plug was separated from its neighbor by a 100 microL air plug. When each plug reached the injection point where both a platinum-wire anode and the end of the separation capillary tube were located, 340 V/cm separation voltage (electrophoresis voltage) and 34 V/cm injection voltage were applied to the capillary for 3 s. Then the analytes were derivatized during migration in 50 microm ID capillaries filled with 2 mM o-phthalaldehyde (OPA)/N-acetylcysteine (NAC) in a 20 mM phosphate-borate buffer (pH 10), followed by separating and detecting of OPA derivatives by absorbance of 340 nm. Derivatization, separation, and detection were performed systematically using capillaries which varied in length from 5 to 80 cm. In the case of TICD-CE of a mixture containing 1 mM aspartic acid (Asp) and 20 mM m-nitorophenol (MNP) as a test solution, it was determined that peak area and peak width ratios of Asp to MNP did not depend on capillary length. Enantiomeric separations of DL-alanine (Ala) and Asp were examined using a run buffer consisting of a 45 microM beta-cyclodextrin (CD)-2 mM OPA/NAC-20 mM phosphate-borate buffer (pH 10). Even though the resolution of these enantiomeric pairs decreased with decreasing capillary length, as expected, the peaks corresponding to both enantiomeric amino acids were identified even when a 5 cm capillary was used. An 8-component amino acid mixture was also tested with 5 cm and 10 cm capillaries. 相似文献
Four new cycloartane glycosides, named aquilegiosides G-J, were isolated from the dried aerial parts of Aquilegia vulgaris. Their structures were determined by spectroscopic analysis and chemical evidence. 相似文献
The complexation behavior, binding properties, and spectral parameters of supramolecular chirality induction in the achiral host molecule, syn (face-to-face conformation) ethane-bridged bis(zinc porphyrin), upon interaction with chiral bidentate guests (diamines and amino alcohols) have been studied by means of UV-vis, CD, fluorescence, (1)H NMR, and ESI MS techniques. It was found that the guest structure plays a decisive role in the chirogenesis pathway. The majority of bidentate ligands (except those geometrically unsuitable) exhibit two major equilibria steps: the first guest ligation leading to formation of the 1:1 host-guest tweezer structure (K(1)) and the second guest molecule ligation (K(2)) forming the anti bis-ligated species (1:2). The second ligation is much weaker (K(1) > K(2)) due to the optimal geometry and stability of the 1:1 tweezer complex. The enhanced conformational stability of the tweezer complex ensures an efficient chirality transfer from the chiral guest to the achiral host, consequently inducing a remarkably high optical activity in the bis-porphyrin. 相似文献
We study the energy diffusion in a chain of anharmonic oscillators where the Hamiltonian dynamics is perturbed by a local energy conserving noise. We prove that under diffusive rescaling of space–time, energy fluctuations diffuse and evolve following an infinite dimensional linear stochastic differential equation driven by the linearized heat equation. We also give variational expressions for the thermal diffusivity and some upper and lower bounds. 相似文献