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991.
X射线辐照前后,在BaF(Cl,Br):Sm^2+中以560nm的Nd:YAG脉冲光在液氮温度下进行了双光子烧孔实验和光激励发光实验,结果表明,Sm^2+掺杂的碱土金属氟卤化物光谱烧孔过程中伴随着光激励发光过程,这一过程直接影响光谱烧孔过程的进行。 相似文献
992.
硫酸溶液中Ag+离子对Mn2+离子阳极氧化的催化作用 总被引:2,自引:0,他引:2
Anodic oxidation of Mn2+ and Ag+ ions and anodic oxidation of Mn2+ ion on platinum electrode in H2SO4 solution catalyzed by Ag+ ion are studied by using RRDE and triangle voltammetry techniques. Mn2+ ion is oxidized on the anode surface with adsorped OH group to form a certain compound containing Mn3+, which causes Mn2+difficult to be oxidized directly on anode. Near the potential of oxygen evolution from H2O decomposition, Ag+ ion is oxidized to form Ag2+ ion. This is the main reaction on anode because of its reversability. At higher potential silver oxide is formed on the anode. The oxide catalyzes the decomposition of H2O strongly. The anodic oxidation of Mn2+ion catalyzed by Ag+ takes place and Ag2+ ion and silver oxide are no longer the product of Ag+ anodic oxidation when Mn2+ exists in solution at the potential for Ag+ anodic oxidation. It is confirmed that the catalysis reaction is homogeneous and very fast. 相似文献
993.
Cheng Y Huang Q Eić M Balcom BJ 《Langmuir : the ACS journal of surfaces and colloids》2005,21(10):4376-4381
We present the first 13C magnetic resonance imaging study of CO2 transient adsorption/desorption processes in a zeolite 5A column. CO2 transient concentration profiles were measured with a centric scan spin-echo single point imaging technique. The adsorption wave profiles were determined under flow conditions, with the results analyzed by the Bohart-Adams model. The model adequately accounts for the spatial and the temporal behavior of CO2 in the column. CO2 adsorption rate constants were calculated from the fit. Desorption profiles were acquired by blowing a helium stream through a zeolite 5A column saturated with CO2. An asymmetry between the adsorption and desorption profiles is readily apparent. A linear relationship between the CO2 condensed phase concentration and square root of time was observed. 相似文献
994.
[reaction: see text] Three organoboron compounds are shown to be two-photon fluorescent sensors for fluoride anion with high sensitivity and selectivity. The recognition mechanism is attributed to the unique steric structure of the bulky dimesitylboryl group and the Lewis acid-base interaction between trivalent boron atom and fluoride anion. 相似文献
995.
996.
Huang HC Lee JF Chao HP Yeh PW Yang YF Liao WL 《Journal of colloid and interface science》2005,286(1):127-133
The influence of natural organic matter (NOM) constituents on contaminant distribution coefficients was evaluated by determining the Koc values of aromatic and aliphatic organic compounds (solutes) with clays modified with both aromatic- and aliphatic-rich organic constituents. The studied compounds consisted of naphthalene, phenanthrene, n-pentane, and 2,3,4-trimethylmethane; the solid samples comprised two clays with little organic content, kaolinite and Ca-montmorillonite. Two aliphatic surfactants and three aromatic dyes, sorbed to the clays, served as reference NOM constituents. For solutes of comparable water solubilities, the organic-carbon normalized distribution coefficients (Koc) of the aliphatic solutes between sorbed aliphatic organic matter and aqueous solution slightly exceed those of the aromatic solutes. By contrast, the aromatic solutes exhibited higher Koc values than did the aliphatic compounds with sorbed aromatic-rich organic matter. The difference in Koc values could be attributed to either comparable solubility parameters or the difference in the chemical structure between nonionic organic solutes and specific components of the simulated NOM. The much higher Koc values observed for the aromatic solutes indicate that the NOM composition is a major factor determining the NOC environmental distribution. 相似文献
997.
Lu C Wei F Wu N Huang L Zhao X Jiao X Luo C Cao W 《Langmuir : the ACS journal of surfaces and colloids》2004,20(3):974-977
A kind of hybrid multilayer film based on mercaptobenzoic acid-capped Au nanoparticles (MBA-Au-NPs) and photoreactive nitrodiazoresin (NDR) has been fabricated via electrostatic self-assembly. Upon exposure to UV light, the initial ionic bonds between the layers of the film convert into covalent bonds and the film stability toward polar solvents, salt, or surfactant solutions increases significantly. The micropatterned NDR/MBA-Au-NP film with the covalently linked architecture was formed by selecting exposure of the film through a photomask and later developed in sodium dodecyl sulfate (SDS) aqueous solution. The metallic Au-NP micropatterns, furthermore, are produced by sintering the micropatterned NDR/MBA-Au-NP film at 550 degrees C, at which the organic components are removed completely. The well-defined micropatterns were characterized with atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), microscope with a charge-coupled device (CCD) camera, and X-ray photoelectron spectroscopy (XPS). 相似文献
998.
Microdialysis sampling coupled with liquid chromatography-electrochemical detection (LC-ED) was developed and applied to determine the interaction of thiopurine (TP) with bovine serum albumin (BSA). A nickel hexacyanoferrate (NiHCNFe) modified electrode was fabricated and used as the working electrode in LC-ED for the determination of TP. Cyclic voltammetric experiments demonstrate that this chemically modified electrode (CME) can effectively catalyze the electrooxidation of TP. The mechanism of the catalytic oxidation of TP at the CME involves an 'EC' process. In the LC-ED, the CME also shows good stability and reproducibility for the determination of TP. The limit of detection is 5.0 x 10(-7) mol l(-1) for 6-TP with a signal-to-noise ratio of 3. The utility of microdialysis as a quantitative sampling technique for in vitro studies of drug-protein interactions was studied. The microdialysis experiments were performed in phosphate buffer solution (pH 7.4) containing different molar ratios of the drug and protein at 37 degrees C. The collected microdialysis sample with unbound TP was analyzed at the NiHCNFe CME in the LC-ED. The relative recovery of TP determined in vitro is 18.3% at a perfusion rate of 1.0 microl min(-1) and the RSD is about 2.1%. The association constant and the number of binding sites on a BSA molecule calculated with the Scatchard equation are 3.72 x 10(-3) (1 mol(-1)) and 1.51, respectively. This method provides a fast, sensitive and simple technique for the study of drug-protein interactions. 相似文献
999.
1000.
应用X-射线单晶衍射方法, 测定2,2-联吡啶(bpy)和簇合物MO_3S_4(μ-dtp)(dtp)_3(H_2O)(Ⅰ)反应产物褰峁埂a果? 产物为Mo_3S_4(μ-dtp)(η~2-dtp)_2(η~1-dtp)(bpy)(Ⅱ), 即联吡啶置换了簇合物(Ⅰ)中的端基(H_2O)和端基(dtp)中的一啮。簇合物(Ⅱ)晶体属三斜晶系。晶胞参数为:a=1.3638(3); b=1.3983(3); c=1.4699(2) nm, a=95.57(2)°, β=91.87(2)°, γ=117.40(2)°; V=2.4676 nm; Z=2; D_C=1.767 g·cm~(-3)。晶体的空间群为P1。最终偏离因子R=0.069, R_w=0.076。本文结合过去对簇合物(Ⅰ)进行的四种不同类型的置换反应的研究, 进行了必要的讨论。并指出本文中的反应是松散本位促进的配基置换反应。 相似文献