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991.
Mao Jia-Jun Chen Yu-De Zhang Gui-Rong Zhou Zu-Ming 《Journal of Radioanalytical and Nuclear Chemistry》1986,100(1):103-115
A study on the synergistic extraction of uranium(VI) from nitric acid media with double-chelating agent systems 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (PMBP) plus thenoyltrifluoroacetone (TTA), and 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 plus 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazolone-5 (PMTFP) is described. Some synergistic effects have been observed. The experimental results suggest that the composition of synergistic complex species is UO2PMBP·TTA and UO2PMBP·PMTFP, respectively. The equilibrium constants for these synergistic extractions are calculated by three methods and the mechanism and the regularity of extraction are discussed as well. 相似文献
992.
Meng Wang Weiyue Feng Junwen Shi Fang Zhang Bing Wang Motao Zhu BaiLi Yuliang Zhao Zhifang Chai 《Talanta》2007,71(5):2034-2039
A mild, efficient and convenient extraction method of using 2-mercaptoethanol contained extractant solution combined with an incubator shaker for determination of mercury species in biological samples by HPLC–ICP-MS has been developed. The effects of the concentration of 2-mercaptoethanol, the composition of the extractant solution and the shaking time on the efficiency of mercury extraction were evaluated. The optimization experiments indicated that the quantitative extraction of mercury species from biological samples could be achieved by using 0.1% (v/v) HCl, 0.1% (v/v) 2-mercapoethanol and 0.15% (m/v) KCl extractant solution in an incubator shaker for shaking overnight (about 12 h) at room temperature. The established method was validated by analysis of various biological certified reference materials, including NRCC DOLT-3 (dogfish liver), IAEA 436 (tuna fish), IAEA MA-B-3/TM (garfish filet), IAEA MA-M-2/TM (mussel tissue), GBW 08193 (bovine liver) and GBW 08572 (prawn). The analytical results of the reference materials were in good agreement with the certified or reference values of both methyl and total mercury, indicating that no distinguishable transformation between mercury species had occurred during the extraction and determination procedures. The limit of detection (LOD) for methyl (CH3Hg+) and inorganic mercury (Hg2+) by the method are both as 0.2 μg L−1. The relative standard deviation (R.S.D.s) for CH3Hg+ and Hg2+ are 3.0% and 5.8%, respectively. The advantages of the developed extraction method are that (1) it is easy to operate in HPLC–ICP-MS for mercury species determination since the extracted solution can be directly injected into the HPLC column without pH adjustment and (2) the memory effect of mercury in the ICP-MS measurement system can be reduced. 相似文献
993.
Using velocity map ion imaging technique, the photodissociation of n-C4H9Br in the wavelength range 231–267 nm was studied. The results and our ab initio calculations indicated that the absorption of n-C4H9Br in the investigated region originated from the excitations to the lowest three repulsive states, as assigned as 1A″, 2A′ and 3A′ in Cs symmetry. Dissociations occurred on the PES surfaces of the three states, terminating in C4H9+Br (2P3/2) or C4H9 + Br* (2P1/2) as two channels, and being impacted by an avoided crossing between the PES surfaces of the 2A′ and 3A′ states. The transition dipole to the 1A″ state was perpendicular to the symmetry plane, so perpendicular to the C–Br bond. The transitions to the 3A′ state was polarized parallel to the symmetry plane, and also parallel to the C–Br bond. While the transition dipole to the 2A′ state was in the symmetry plane, but formed an angle of about 53.1° with the C–Br bond. We have also determined the avoided crossing probabilities, which affected the relative fractions of the individual pathways, for the photolysis of n-C4H9Br near 234 nm and 267 nm. 相似文献
994.
Xiaohua Zou Song Zhang Mianhong Shi Jilie Kong 《Journal of Solid State Electrochemistry》2007,11(2):317-322
A stepwise deposition method was employed to create ordered polyaniline (PANI) nanowires with remarkably enhanced capacitance. Cyclic voltammetry, AC impedance, and galvanostatic charge/discharge cycling were employed to investigate the electrochemical performance of the PANI electrodes. The PANI-deposited electrode exhibits much higher capacitance than those prepared by one-step deposition method, which were mainly contributed from the unique nano structure of PANI and the increased biological, economical, and technical surface areas. The superior capacitive behaviors of the nano PANI electrodes show great potential in preparation of high efficient electrochemical capacitors or rechargeable batteries. 相似文献
995.
Xiangfu Zhang Fei XieZhonglin Pen Yong ZhangYinxi Zhang Wen Zhou 《European Polymer Journal》2002,38(1):1-6
The effect of the sorbital nucleating agent on properties of the ethylene-octene copolymer (POE) toughened polypropylene (PP) was studied. The results show that the addition of POE increases notched Izod and Charpy impact strength significantly but impair the tensile strength and flexural modulus. As a nucleating agent (1,3,2,4-di(p-methylbenzylidene) sorbitol, DM) was added, the toughness and stiffness of toughed PP increased simultaneously at the same content of POE. This result shows that the toughness and stiffness of toughed PP are in balance. Polarized light microscopy analysis shows that with the addition of POE and nucleating agent, only a low level of PP spherulites were observed. 相似文献
996.
[reaction: see text] Reactions of alkylmercury chlorides with arene manganese tricarbonyl complexes in the presence of NaI led to the formation of the addition-reduction products. The mechanism was postulated to be the alkyl radical addition to ArMn(CO)3+ cation to form the corresponding 17 valence electron intermediate, which was then reduced by alkylmercury chloride via a singlet electron transfer process to afford the product and regenerate an alkyl radical. 相似文献
997.
The interaction of cyclodextrins with meso- Tetrakis (4-N-trimethylaminobenzyl) porphyrin (TAPP) in 0.1 mol l(-1) phosphate buffer (pH 7.0, 20 degrees C) has been studied by polarography. The TAPP can form the 1:1 inclusion complex with Sulfobutylether-beta-cyclodextrin (SBE-beta-CD) and1:2 inclusion complexes with other four cyclodextrins. A new expression, which is used to calculate the inclusion constant for1:2 inclusion complex by polarography, has been educed and testified firstly in this paper. Furthermore, the inclusion abilities of different kinds of cyclodextrins are compared. The result shows the inclusion ability of anionic cyclodextrin SBE-beta-CD with cationic porphyrin TAPP is very strong. It suggests that the charge attraction between CDs and TAPP plays an important role in the inclusion procedure except for the hydrophobic effect. The inclusion formation of anionic cyclodextrins with drugs can increase released rate of drugs at high pH; therefore, the suparmolecular data for the controlled release of the drugs that owned the similar properties as hematoporphyrin have been offered by polarography in this paper. 相似文献
998.
热处理对聚乙烯/炭黑导电复合体系形态结构及PTC特性的影响 总被引:11,自引:3,他引:11
借助WAXD、SAXD和DSC等手段研究了炭黑与聚乙烯复合体系在不同热处理条件下的结晶行为及聚集态结构的大尺寸效应对PTC特性的影响。由此提出,不仅结晶度大小,而且聚集大尺寸效应性能对PTC行性有重要影响的新观点。 相似文献
999.
加速剂对化学镀镍层组成与结构的影响 总被引:3,自引:0,他引:3
加速剂对化学镀镍层组成与结构的影响方景礼,武勇,韩克平,张敏(南京大学应用化学研究所配位化学国家重点实验室南京210093)关键词化学镀镍,Ni0P合金,加速剂,硫脲化学镀镍磷合金具有耐蚀性、可焊性、厚度均匀和硬度高等优点,已得到广泛应用。为提高生产... 相似文献
1000.
天然和人工培植红景天挥发油的对比研究 总被引:2,自引:0,他引:2
应用GC-MS和GC-IR两种联机法对比研究了天然和人工培植红景天挥发油、分别鉴定出27个和24个化合物。MS给出结构信息和IR给出官能团信息相结合,提高了分析测试复杂样品的可靠性。 相似文献