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41.
In this work, the surface properties of novel sugar-containing polymers, α-allyl glucoside (AG)/acrylonitrile (AN)copolymers, were studied by contact angle, protein adsorption and cell adhesion measurements. It was found that the contactangle of the copolymer films decreased from 68° to 30° with the increase of AG content in the copolymer. The adsorptionamount of bovine serum albumin (BSA) and the adhesive macrophage onto the film surface also decreased significantly withincreasing α-allyl glucoside content from 0 to 42 wt% in the copolymer. These preliminary results reveal that both thehydrophilicity and the biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerizing acrylonitrile with vinyl carbohydrates. 相似文献
42.
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44.
The calculations of clusters modeling the fluorine-doping and oxygen deficiency of YBa2Cu307 have been performed by the method of all-electronab initio Hartree-Fock with self-consistent crystal field. Results show that in CuO planes electric charge significantly increases,
the chemical valence of Cu decreases and the covalent bonding of Cu-O greatly weakens owing to oxygen deficiency, while the
effect of F restores the local electronic structure of YBa2Cu3O7. The reported opinion that F occupied the oxygen vacancy in Cu-O chains seems disputable according to the calculated bonding
characteristics
Project supported by the National Natural Science Foundation of China. 相似文献
45.
Xiong Wen Ye Yu Ping Zhang Ling Bo Qu Li Qun Fan Bo Li 《中国化学快报》2007,18(11):1399-1402
Microwave irradiation was firstly attempted for the preparation of organic-based monoliths of poly(styrene-divinylbenzene- methacrylic acid), which single step in situ polymerization was carried out during 15 min. The colunm permeability, electrophoretic and chromatographac behaviors were comparatively evaluated using pressure-assisted CEC, GEC and low pressure-driven separation modes. The largest theoretical plates for the preparing column could be close to 18,0000 plates/m for thiourea in the mode of p-CEC. It provided a viable alternative to traditional initiation means for the perparation of monolithic capillary columns. 相似文献
46.
Changmei Sun Rongjun Qu Qiang Xu Chunnuan Ji Yanzhi Sun 《European Polymer Journal》2007,43(4):1501-1509
Two novel chelating resins were prepared by anchoring ethylenediamine to crosslinked polystyrene via a spacer containing sulfide. Their structures were characterized by Fourier transform-infrared spectra (FTIR) and scanning electron microscopy (SEM). Porous structure parameters of the resins were measured by ASAP 2020 using BET and BJH methods. Their adsorption capacities for several heavy metal ions especially Hg2+ were investigated. The results showed that for the two resins, the more N contents did not mean the better adsorption capacity and the saturated adsorption capacity of poly(2-ethylenediamidomercaptomethylstyrene) (PSM-EDA) for Hg2+ could reach to 3.0 mmol/g at room temperature. Isothermal adsorptions of the resins for Hg2+ could be described by Langmuir formula. The adsorption mechanism of the resins for Hg2+, Cu2+ and Ag+ was confirmed by X-ray photoelectron spectroscopy (XPS) and FTIR. 相似文献
47.
Fu L Wu NQ Yang JH Qu F Johnson DL Kung MC Kung HH Dravid VP 《The journal of physical chemistry. B》2005,109(9):3704-3706
Supported gold catalysts have drawn worldwide interest due to the novel properties and potential applications in industries. However, the origin of the catalytic activity in gold nanoparticles is still not well understood. In this study, time-of-flight secondary ion mass spectroscopy (TOF-SIMS) has been applied to investigate the nature of gold in Au (1.3 wt %)/gamma-Al2O3 and Au (2.8 wt %)/TiO2 catalysts prepared by the deposition-precipitation method. The SIMS spectrum of the supported gold catalysts presented AuO-, AuO2-, and AuOH- ion clusters. These measurements show direct evidence for oxidized gold on supported gold catalysts and may be helpful to gaining better understanding of the origin of the catalytic activity. 相似文献
48.
Z. H. Zhang Z. J. Ku H. R. Li Y. Liu S. S. Qu 《Journal of Thermal Analysis and Calorimetry》2005,79(1):169-173
The solid-state ternary complex of terbium chloride with L-tyrosine and glycine, [Tb(Tyr)(Gly)3Cl3·3H2O], was synthesized and characterized. Using a solution-reaction isoperibol calorimeter, the enthalpy of reaction for the following reaction, TbCl3·6H2O(s)+Tyr(s)+3Gly(s)=Tb(Tyr)(Gly)3Cl3·3H2O(s)+3H2O(l), was determined to be (5.1±0.6) kJ mol-1. The standard enthalpy of formation of Tb(Tyr)(Gly)3Cl3-3H2O at T=298.15 K has been derived as -(4267.3±2.3) kJ mol-1. The thermal decomposition kinetics of the complex was studied by non-isothermal thermogravimetry in the temperature range of 325-675 K. Two main mass loss stages existed in the process of the decomposition of the complex, the kinetic parameters for the second stage were analyzed by means of differential and integral methods, respectively. Comparing the results of differential and integral methods, mechanism functions of the thermal decomposition reaction for its second stage were proposed. The kinetic equation can be expressed as: d/dt=Aexp(-E/RT)(1-)2. The average values of the apparent activation energy E and pre-exponential factor A were 213.18 kJ mol-1 and 2.51·1020 s-1, respectively. 相似文献
49.
This paper introducesa novel method for packing Capillary Electrochromatography Columns (CEC). Using vacuum packing methodology, silica particles as small as 1 microm were successfully packed into the capillary columns with 75 microm inner diameter. The columns are verystable and show no noticeable loss in efficiency after 200 sample injections. The performance of these vacuum packed capillary columns was evaluated with a mixture of aromatic and non-aromatic compounds. A 24 cm long capillary column can produce peak efficiencies of around 45,000 plates for benzene. 相似文献
50.
In this paper, cyclic voltammetry, linear sweep voltammetry and chronocoulometry in connection with the hang mercury drop electrode were used to study NiTMpyP and its mixture with DNA. The reduction of NiTMpyP in our experimental conditions involves in 4e reduction of TMpyP. NiTMpyP interacting with DNA forms electrochemically non-active complex DNA-2NiTMpyP, which can not be reduced on the Hg electrode. The peak potential of NiTMpyP does not shift and its electrochemical kinetic parameters indicate no significant change in the presence of DNA. However, the reduction current of NiTMpyP decreases obviously due to the formation of DNA-2NiTMpyP, which implies its equilibrium concentration decreases when DNA was mixed. The decrease of peak current is proportional to DNA concentration, which can be applied to estimate DNA concentration. 相似文献