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991.
Majid M. Heravi Khadijeh Bakhtiari Negar M. Javadi Hossein A. Oskooie Fatemeh F. Bamoharram 《Monatshefte für Chemie / Chemical Monthly》2007,138(5):445-447
Summary. Acetylation of various alcohols and benzyl amine was tested in the presence of H6[PMo9V3O40], a mixed addenda heteropolyacid, in ethyl acetate under reflux condition. Phenols and anilines are not affected under the
reaction conditions. Selective transestrification of alcohols can be achieved in the presence of phenol and aniline derivatives
using this method. 相似文献
992.
通过ESR光谱测定表明TiO2悬浮液在紫外光照射下产生羟基自由基氧化物种.羟基自由基氧化酸性桃红(sulforhodamine B,SRB)使其褪色,在565 nm处用分光光度法测定其吸光度值的变化,可间接测定羟基自由基的生成量.确定了体系的最佳实验条件pH为2.5;SRB浓度为2.0×10-5mol/L;TiO2浓度为0.1 g/L;光照时间为12 min.采用抗坏血酸为羟基自由基清除剂,测定了其自由基清除率,表明拟定该体系可作为筛选抗氧化剂的方法之一. 相似文献
993.
Kai‐lu Yu Chang‐jun Liu Yue‐ping Zhang Fei He Xin‐li Zhu Baldur Eliasson 《Plasma Chemistry and Plasma Processing》2004,24(3):393-403
PdO/Al2O3 catalysts prepared by glow discharge plasma treatment followed by thermal calcination show a much higher dispersion and a better catalytic activity for methane combustion at relatively low temperatures. The dispersion of palladium active species by such plasma prepared catalysts is 29.7%, 5.4 times higher than that of conventional catalysts. XPS analysis indicates that a surface enrichment of Pd active species (PdO) has been achieved after plasma treatment. The surface atomic composition of PdO of plasma prepared catalysts reaches 10.5%. XRD characterization also confirms a wellcrystallized PdO phase present on the plasma prepared catalyst. The lightoff temperature of the plasma prepared catalyst is 370°C, 50°C lower than that obtained from the conventional catalyst. 相似文献
994.
Jiang Ke QIN Xian Zhang BU Yu Fang WANG Zhi Yun DU Xing Yuan WANG Zhi Shu HUANG Lin MA Lin Kun AN Lian Quan GU 《中国化学快报》2005,16(11):1451-1454
The reactions of tanshinone IIA with aromatic aldehydes have been investigated and several 2, T-(substituted arylmethylene) bis (1,6,6-trimethyl-6,7,8,9-tetrahydrophenanthro[1,2-b]- furan- 10, 11-dione) derivatives were obtained, 相似文献
995.
996.
František Kvasnička Jaroslav Dobiáš Kamila Klaudisová-Chudáčková 《Central European Journal of Chemistry》2003,1(1):91-97
A simple, rapid and reproducible capillary isotachophoretic on-line coupled with capillary zone electrophoresis (CITP-CZE)
method for the determination of IMz in food packaging extracts and its residues in apples is described. A good separation
of the IMZ from other sample constituents was achieved within 15 minutes without any sample clean up. Method characteristics
(linearity, accuracy, intra-assay and detection limit) were determined. Less amount of time involved, sufficient sensitivity
and low running cost are the important attributes of CITP-CZE method. 相似文献
997.
Nataša Pejić Slobodan Anić Vesna Kuntić Vladana Vukojević Ljiljana Kolar-Anić 《Mikrochimica acta》2003,143(4):261-267
A kinetic method is described for the microquantitative (microconcentration/microvolume) determination of rutin based on potentiometric monitoring of the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory reaction being in a non-equilibrium stationary state close to a bifurcation point. The experiments are carried out in an open reactor. The response of the matrix system to perturbations by different concentrations of rutin ethanolic solutions is followed by a Pt-electrode. In the concentration range between 7.8×10–8moldm–3 and 9.1×10–6mol dm–3, we found a linear dependence of the maximal potential shift, Em, on the logarithm of the rutin concentrations. The unknown concentrations can be determined from the calibration curve up to an accuracy of ±5%. The detection limit is 3.6×10–8mol dm–3. The amount of required sample can be as small as 10µL. 相似文献
998.
Hiléia K. S. Souza V. R. da Silveira F. M. M. Borges Dulce M. A. Melo H. Scatena Jr. O. A. de Oliveira A. G. Souza 《Journal of Thermal Analysis and Calorimetry》2007,87(2):433-436
Thermal behavior of rare earth nitrate complexes
with 2-azacyclononanone (AZA) with Ln(NO3)3·3(AZA)
composition (where Ln=Gd, Er and Ho) was
analyzed in kinetic point of view. Kinetic parameters were calculated from
thermogravimetric data. All obtained results were similar. The first decomposition
step was representative to the loss of ligand and the residue was essentially
Ln2O3. Furthermore, a reaction
path was proposed for the thermal decomposition of the Ln(NO3)3·3(AZA). 相似文献
999.
Xiaodong Zhang Dexu Lin Zhengmin Liu 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(1):149-151
Summary The elastic scattering cross sections of natural vanadium for protons have been measured for beam energies below 2.64 MeV in steps of 10 keV and in the angular 160° and 170°. The overall standard error (ΔσExp/σExp) in the measured cross sections is estimated to be better than ±3% at all the beam energies and angles. The results are presented in graphical and tabular forms that should be useful for those who wish to use the cross sections for material analysis. 相似文献
1000.