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11.
ToF-SIMS analysis of the organometallic cluster Os3(μ-H)(CO)10(μ-SCH2CH2SH) chemically attached onto a silver or gold surface, and of the cluster fragment Os3(μ-H)(CO)10(μ-OSi) on a silica surface, allows for identification of the surface organometallic species, and also gives information on its reactivity.  相似文献   
12.
We report molecular dynamics (MD) simulations on the adsorption of water in attractive and repulsive slit pores, where the slit and a bulk region are in contact with each other. Water structure, surface force and adsorption behavior are investigated as a function of the overall density in the bulk region. The gas–liquid transition in both types of pores occurs at similar densities of the bulk region.  相似文献   
13.
The surface chemical composition of raw unscoured cotton was successfully investigated by the surface analytical techniques X-ray Photoelectron Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The presence of non-cellulosic material at the fibre surface was established and determined to be a complex mixture of fatty acids, alcohols, alkanes, esters and glycerides. The effect of scouring and bleaching was to reduce the surface concentration of these materials but even after aqueous processing some non-cellulosic material residue was still detected at the fibre surface.  相似文献   
14.
一种新型的表面声波阻抗传感器及其在液相体系中的应用姚守拙,陈康,刘德忠,聂利华(湖南大学化学化工系,长沙,410082)关键词表面声波,阻抗传感器,液相应用表面声波传感器(SAWS)具有较高的灵敏度和检测精度,已广泛应用于气体微量组分分析、色谱检测和...  相似文献   
15.
The surface basicity of Ti-La-Li multicoinponent oxides has been investigated by means of CO2-TPD. The experiment results show that C2 (C2H6 C2H4) selectivity is related to surface basic strength. The surface active oxygen species have also been characterized by means of XPS, O2-TPD and so on. It has been indicated that C2 selectivity and CH4 conversion are correlated with lattice oxygen and the adsorbed oxygen on the surface of the catalyst respectively In the O2-TPD experiments, it has also been found that there are three kinds of oxygen species on the surface of the series catalvsts, which are a (100℃ 750℃) Among them α-oxvgen causes deep oxidation whileβand γ oxygen species are related to oxidalive coupling of methane (OCM).  相似文献   
16.
The interaction of dimethyltin dichloride (Me2SnCl2) with calf thymus DNA was studied at 27 °C, pH 7.6 using various techniques including isothermal titration calorimetry (ITC) and UV-Vis, fluorescence and IR spectrophotometries. The binding isotherm and enthalpy curve for Me2SnCl2-DNA interaction was a biphasic transition process. This was determined by the analysis of the binding data with the Hill equation. The first phase of the enthalpy curve (exothermic process) was consistent with the first set of binding site, the second phase (endothermic process, less exothermicity) was consistent with second set of binding site from the cited interactions. Our results showed that the first set of binding sites is occupied by one mole of ligand bound per near 1 base pair of DNA. The DNA-ethidium bromide (EB) complex, in the presence of Me2SnCl2, caused the quenching of the fluorescence emission. The Scatchard plots illustrated a non-intercalating manner for such quenching. The DNA-EB complex results indicated that the binding of Me2SnCl2 is with the phosphate groups of DNA at low ligand concentrations (<9 mM). This was confirmed with the IR spectrophotometric spectra. However, the binding at higher ligand concentrations (>9 mM) was with the base groups of DNA. Therefore, these results suggest that the Me2SnCl2 binding to DNA at low concentrations occurs through an outside interaction by an exothermic process. However, the partial unfolding of the DNA caused at higher concentrations of Me2SnCl2 is through an endothermic process involving interactions with the base groups.  相似文献   
17.
The synthesis of the naturally occurring and biologically active alkaloids 1 and 2, first isolated from the red ascidian Botryllus leachi by Duran et al. [1], is described and the structure proposed for Botryllazine B (1) is confirmed. The analytical data for 2-(p-hydroxybenzoyl)-4-(p-hydroxyphenyl)imidazole (2) are discussed and compared with the literature. With special emphasis of 1H NMR data the tautomerism of aroylimidazolemethanones is described.  相似文献   
18.
To reduce the amount of hazardous chemical bottle waste in the environment, we report the optimization research of silica extraction in chemical bottle waste into silica gel. Alkali fusion and sol–gel process were utilised to prepare silica gel effectively. The alkali fusion process was carried out by adding sodium hydroxide to produce sodium silicate. Afterwards, silica gel was prepared by the sol–gel method using hydrochloric acid. Box-Behnken Design (BBD) was applied to Optimisation factors the poptimiseactors affecting the silica recovery. The factors that optimised mass ratio, particle size, and temperature. The optimum recovery of silica gel was obtained by SiO2: NaOH mass ratio of 1:3, the particle size of 63–74 µm, and a temperature of 800 °C. The purity of silica gel optimum is 63.74% characterised using X-ray fluorescence. The structure of silica gel is the appearance of amorphous peaks at 2θ 20-30° characterised using an x-ray diffractogram. The silica gel surface was characterises using scanning electron microscopy-energy dispersive x-ray. It showed an irregular surface and characteristic showed that silica gel had a radius of 15.74 nm and a specific surface area of 297.08 m2.  相似文献   
19.
In this paper, geometric bulk parameters, bulk moduli, energy gaps and relative stabilities of the TiO2 anatase and rutile phases were determined from periodic DFT calculations. Then, for the rutile phase, structures, relaxations and surface energies of the (110), (100), (101) and (001) faces were computed. The calculated surface energies are consistent with the natural rutile powder composition, even if a dependence on the number of layers of the slab used to model the surface was identified. Internal constraints, consisting in freezing some internal layers of the slab to atomic bulk positions, were thus added to mimic the bulk hardness in order to stabilise the computed surface energies for thinner systems. In parallel, the influence of pseudopotentials was studied and it appears that four valence electrons for titanium atoms are sufficient. The aim of this study was to optimise accurate rutile TiO2 surface models that will be used in further calculations to investigate water and uranyl ion sorption mechanisms.  相似文献   
20.
Crosslinked films consisting of the acrylamide-acrylamidophenylboronic acid copolymer that are imprinted with recognition sites for β-nicotinamide adenine dinucleotide (NAD+), β-nicotinamide adenine dinucleotide phosphate NADP+, and their reduced forms (NAD(P)H), are assembled on Au-coated glass supports. The binding of the oxidized cofactors NAD+ or NADP+ or the reduced cofactors NADH or NADPH to the respective imprinted sites results in the swelling of the polymer films through the uptake of water. Surface plasmon resonance (SPR) spectroscopy is employed to follow the binding of the different cofactors to the respective imprinted sites. The imprinted recognition sites reveal selectivity towards the association of the imprinted cofactors. The method enables the analysis of the NAD(P)+ and NAD(P)H cofactors in the concentration range of 1×10−6 to 1×10−3 M. The cofactor-imprinted films associated with the Au-coated glass supports act as active interfaces for the characterization of biocatalyzed transformations that involve the cofactor-dependent enzymes. This is exemplified with the characterization of the biocatalyzed oxidation of lactate to pyruvate in the presence of NAD+ and lactate dehydrogenase using the NADH-imprinted polymer film.  相似文献   
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