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981.
982.
Hong Shen James E. Mark Carl J. Seliskar Harry B. Mark Jr. William R. Heineman 《Journal of Solid State Electrochemistry》1997,1(3):241-247
One problem associated with using bare solid metal electrodes, such as gold and platinum, in stripping analysis to determine
heavy metal ions such as lead and copper ions in dilute solutions is that underpotential deposition (UPD) gives multiple stripping
peaks in the analysis of mixtures. These peaks are often overlapped and cannot be conveniently used for analytical purposes.
Bifunctional alkylthiols, such as 3-mercaptopropionic acid, with an ionizable group on the other terminal end of the thiol
can form self-assembled monolayers (SAMs) on the surface of the gold electrode. It is shown that such an SAM-modified gold
electrode minimizes the UPD effects for the stripping analysis of lead and copper. The anodic peak potential shifts and the
peak shape changes, indicating that the SAM changes the deposition and stripping steps of these heavy metal ions. Thus, the
sensitivity levels for both single species and mixtures can be significantly improved for the conventional solid electrodes.
The mechanism of the deposition reaction at the SAM-modified gold electrodes is discussed.
Received: 29 May 1997 / Accepted: 24 June 1997 相似文献
983.
人工神经网络法预测炸药组分的色谱保留值参数 总被引:1,自引:0,他引:1
以分子拓扑指数作为炸药组分的结构描述符 ,利用反向传播算法 (BP)人工神经网络 ,以Sigmoid函数为传递函数 ,分子连接性指数0 χ ,1χ ,2 χ与边邻接指数 (ε)为输入向量 ,反相高效液相色谱保留值参数logkw 和S为输出向量 ,将输入向量归一化至 - 3~ 3区间 ,输出向量归一化至 0~ 1区间 ,网络精度取 0 5 ,学习步长 η的初始值取0 2 ,动量因子α取 0 5 ,通过对 2 0种炸药的网络模型进行训练 ,建立了炸药分子结构与logkw 和S之间的定量模型。结果表明 ,该模型较好地反映了炸药分子结构与保留值之间的关系。 相似文献
984.
985.
A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for thefirst time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. Themonomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoatewith trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp_2PtCl_2) catalyst. Combination of FTIR,~1H-NMr, ~(13)C-NMR, ~(29)Si-NMR, XRD, DSC, TGA and VPO methods was used to demonstrate that the polymer obtained hasan ordered ladderlike structure. The synthesized Ester-T may have promising applications as a precursor of advanced functional polymers. 相似文献
986.
987.
Jian Hua TONG Wei Shen YANG* Rui CAI Bai Chun ZHU State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences P. O. Box Dalian 《中国化学快报》2001,(9)
Zirconia with fluorite structure stabilized by doping rare earth or alkaline earth metal oxides such as Y2O3 and CaO (YSZ and CSZ) is a class of traditional mixed conducting membrane materials, which have been widely investigated for their high oxygen ionic conductivity and excellent chemical and thermal stability1-3. But the electronic conductivity of these materials is very small, unless operated with an internal or external circuitry, the oxygen flux through membranes in usual ranges of … 相似文献
988.
Hydrogen Permeation Properties of Perovskite-type BaCe_(0.9)Mn_(0.1)O_(3-δ)Dense Ceramic Membrane 总被引:1,自引:0,他引:1
Guang Tao LI Guo Xing XIONG* Shi Shan SHENG Wei Shen YANG State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 《中国化学快报》2001,(10)
In recent years, mixed-conducting oxides, in which both protonic and electronic charge carriers exist, have received increasing attentions1. Ceramic membranes made of such materials are semipermeable to hydrogen at elevated temperatures. In the early 1980s, Iwahara et al. first reported protonic conduction in SrCeO3-based materials2. Later, BaCeO3 system was extensively studied because of its higher conductivities. However, the electronic conductivity of rare earth doped-BaCeO3 ceramic… 相似文献
989.
R Hu T Fu XB Zhang RM Kong LP Qiu YR Liu XT Liang W Tan GL Shen RQ Yu 《Chemical communications (Cambridge, England)》2012,48(76):9507-9509
A proximity-dependent surface hybridization strategy is employed for designing a "signal-on" electrochemical DNAzyme biosensor. By taking advantage of the high sensitivity of the PDSH strategy, and by realizing the enzymatic hydrolysis reaction in a homogenous system with a unimolecular design, the proposed biosensor shows a very high sensitivity to target molecules. 相似文献
990.