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以tiron作为柱前衍生试剂,用含3mmol·L-1pH 3.8的HOAc-NaOAc,40mmol·L-1TBA-Br和2mmol·L-1tiron的甲醇-水溶液(53+47)作流动相,在C18柱上,于15min内实现了WO42-、MoO42-的分离测定。钨和钼的检出限分别为5.98和3.20ng·ml-1。方法快速,选择性好,用于钢及合金中高含量钨和钼的测定,结果与标准值相符。 相似文献
236.
Ya Wen TANG Shuang CAO Ling Ling ZHANG Jian Chun BAO Ping ZHOU Tian Hong LU 《中国化学快报》2006,17(12):1623-1626
The performance of the direct formic acid fuel cell (DFAFC) is considerably higher than the direct methanol fuel cell (DMFC) because of some characteristics of formic acid1. For example, formic acid is non-toxic. Formic acid has two orders of magnitude smaller crossover flux through a Nafion membrane than methanol2. In DFAFC, the concentration of formic acid can be as high as 20 mol/L, while the best concentration of methanol in DMFC is only about 2 mol/L3. Thus, the power density of … 相似文献
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The effects of variant counterions with ionic strength of 0.05, 0.10, 0.20 and 0.25 mol·kg^-1 on the stability and particle size of silica sols have been studied using the traditional methods of Ubbelohde viscosity measurement, TEM and titration respectively, finding that the stability and particle size of the silica sols are all concerned with the acidic, positively electric properties and the sizes of the counterions, as well as the attraction between the counterions and surface silicon hydroxyl groups of the silica sols. The small positively charged counterions lead to the decrease in particle sizes, making the silica sol the most stable. But the larger weakly acidic counterions can restrict the particle sizes of the silica sols and easily make the sols coagulate. It was also found that there existed a linear relationship between log r and log η, which has not ever been reported. The effect of temperature on the stability and particle sizes was also discussed. 相似文献
239.
SYNTHESIS OF ASILICA-SUPPORTED CARBOXYMETHYL CELLULOSE PLATINUM COMPLEX AND ITS CATALYTIC BEHAVIORS FOR HYDROGENATION OF ETHY... 相似文献
240.
The adsorption of a surfactant mixture, based on an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS) and a nonionic
surfactant (Triton X-100, or TX100), on alumina nanoparticles was determined by solution depletion method combined with spectrometric
measurement. It is shown that the light scattering, originated from the residual adsorbent alumina particles in the supernatant
after centrifugation separation, interferes with the measurements of absorbance of the surfactant molecules, and therefore
constitutes an error source for determination of the surfactant concentration in the supernatant by spectrometric means. The
intensity of this light scattering, namely the influence of the residual alumina nanoparticles upon the surfactant adsorption,
was related to the surfactant adsorption and its equilibrium concentration and varied among a batch. In this paper we report
a Kalman filter method in order to eliminate the variational scattering background caused by non-separated residual alumina
nanoparticles in each supernatant. This method is of interest as it is simple, easy to carry out and of high precision. 相似文献