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本文以实验为基础,运用计算机数值解解出双电层相互作用时平面胶体表面电位ψ随距离X的分布,依据作者导出的双电层相互作用时胶体表面阴离子负吸附方程,计算出胶体表面外Hclmhotz面(OHP)处的表面电荷密度σ_δ;讨论了双电层相互作用程度(ψ_d/ψ_δ)对胶体表面电位分布及其表面电荷密度的影响。 相似文献
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碱性水溶液中甲醛在硅电极表面的电化学行为及其对硅化学刻蚀的影响 总被引:1,自引:0,他引:1
研究了KOH水溶液中氧化剂甲醛在p-Si和n-Si(100)单晶半导体电极表面的电化学行为及其对硅化学刻蚀表面形貌的影响.实验结果表明,甲醛不仅影响p-和n-型半导体电极在碱性溶液中的阳极氧化峰电流,而且在负电位区能在Si(100)电极上发生还原.在光照条件下,p-Si(100)电极上也观测到了HCHO的电化学还原及光电流倍增效应.甲醛在硅电极表面的电化学还原反应分两步进行,反应终产物为甲醇.此外,HCHO能有效抑制碱性溶液中Si表面“金字塔”型表面粗糙颗粒的形成。 相似文献
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提出了一种计算蛋白质水合自由能的简化模型(SAWSA 2).模型把蛋白质分子中的原子分为20种不同的原子类型,通过每类原子的溶剂可及化表面以及相应的溶剂化参数,就可以得到分子的水合自由能.不同原子类型的溶剂化参数通过110个蛋白质分子水合自由能拟合得到,水合自由能的标准值采用了基于求解Possion-Boltzmann方程(PB)以及分子表面计算(SA) 相结合的方法.采用得到的模型,预测了20个蛋白质分子的水合自由能,预测值的相对值和绝对值都能和PB/SA的计算值很好地吻合,大大优于两种已报导的水合自由能模型. 相似文献
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通过表面张力、Zeta电位和流变学参数的测定, 研究了聚氧乙烯烷基醚类非离子型表面活性剂(Brij 30和Brij 35)在合成锂皂石(Laponite)纳米颗粒表面的吸附及对Laponite水分散体系中颗粒间相互作用和体系粘度的影响. 结果表明, 这类表面活性剂能显著地吸附在Laponite颗粒表面上, 且吸附量随其分子中POE链长短而不同. 这种吸附没有改变Laponite粒子的带电性质, 但一定程度地降低了Laponite颗粒Zeta电位; 吸附也会减弱颗粒间的相互作用, 降低体系的粘度. 实验以Laponite和Brij为乳化剂, 制备了O/W型乳状液. 乳液稳定性变化和乳液粒径分布结果表明, 体系中Brij的浓度较低时, 乳液的性质主要是由Laponite颗粒决定的; 而Brij浓度较高时, 则主要取决于Brij表面活性剂. 高速剪切含Brij的Laponite水分散体系, 剪切后表面张力随时间的变化表明, 剪切作用会使得吸附在Laponite颗粒表面的Brij分子不同程度地解吸下来. 这也意味着乳液制备时, 高速剪切作用也会造成Brij分子自Laponite颗粒表面的脱附, 这可能是非离子表面活性剂与阳离子表面活性剂对负电固体颗粒稳定乳液影响不同的原因. 相似文献
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Electronic states of a Ni(001) surface atom, corresponding to different d-occupations, are calculated for a 49 atom cluster model of the surface. SCF and CI calculations on a variety of low lying states are reported. Strong mixing between d9 and d10 configurations is found for the lowest states of different symmetries with the splitting between the states ranging from 1.7 to 2.0 eV. In contrast, the d8 configurations do not interact strongly with other d configurations and lie energetically much higher at 3.0 eV. Thus, the splitting between d9 and d10 configurations is comparable to that of the isolated atom whereas the d8 configuration is greatly destabilized. The cluster produces a manifold of closely spaced electronic states above the ground state thus modeling the density of unoccupied states above the Fermi level. 相似文献
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P. Baltayan F. Hartmann L. Hikmet J. -C. Pebay-Peyroula N. Sadeghi 《Chemical physics letters》1989,160(5-6):549-554
Electronic chemiluminescence from the reaction of selected ground state (2S1/2) or metastable (2D5/2, 2D3/2) copper atoms with fluorine has been studied using a hollow cathode-flowing afterglow reactor. The observed signal related to the Cu(2S) and Cu*(2D) atom densities, indicate that the chemiluminescence cross-section for Cu*(2D) atoms is about 104 times larger than for Cu(2S) atoms. This strong propensity is explained in terms of a direct reaction, initiated by a harpooning process, during which the Cu+ ion core of the reactant (3d10 for Cu(2S) and 3d94s for Cu*(2D)) is conserved in the products (ionic structure Cu+(3d10)F− for the CuF ground state and Cu+(3d94s)F− for the CuF*(a, A, B, C, D) chemiluminescent states). 相似文献
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Comparative studies on excitation of nickel ionic lines between argon and krypton glow discharge plasmas 总被引:2,自引:0,他引:2
Kazuaki Wagatsuma Hitoshi Honda 《Spectrochimica Acta Part B: Atomic Spectroscopy》2005,60(12):1538-1544
The emission characteristics of nickel ionic lines in a glow discharge plasma are investigated when argon or krypton was employed as the plasma gas. Large difference in the relative intensities of nickel ionic lines which are assigned to the 3d84p–3d84s transition is observed between the krypton plasma and the argon plasma. Different intense Ni II lines appear in the krypton spectrum and in the argon spectrum, such as the Ni II 231.601 nm for Kr and the Ni II 230.009 nm for Ar. The excitation energy of these Ni II emission lines can give a key in considering their excitation mechanisms. The explanation for these experimental results is that charge-transfer collisions between nickel atom and the plasma gas ion play a major role in exciting the 3d84p excited levels of nickel ion. The conditions for energy resonance in the charge-transfer collision determine particular energy levels having much larger population; for example, the 3d84p 4D7/2 level (6.39 eV) for Kr and the 3d84p 4P5/2 level (8.25 eV) for Ar. 相似文献
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Study on the Radius of an Electrical Spherical Micelle: Functional Theoretical Approach 总被引:1,自引:0,他引:1
For the purpose of eliminating restriction, the Poisson-Bokzmann (PB) equation, which represents the potential of the electrical double layer of spherical miceUes, can be solved analytically only under the lower potential condition, a kind of iterative method in functional analysis theory has been used. The radius of the spherical particle can be obtained from the diagram of the second iterative solution of the potential versus the distance from the center of the particle. The influences of the concentration of the ions, the charge number of ions, the aggregation number of the particle, the dielectric constant of solvent and the temperature of system on the radius also have been studied. 相似文献
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LIU Qing HUAN Yanfu ZHENG Qingchuan FEI Qiang FEI Yanqun FAN Qian FENG Guodong SHAN Hongyan 《高等学校化学研究》2016,32(5):736-741
A novel high selective and sensitive fluorescence probe termed gatifloxacin was discovered based on fluorescence "on-off" phenomenon in the presence of Se(Ⅳ). In the Tris-HCl/acetonitrile(3:7, volume ratio, Tris-HCl 0.05 mol/L, pH=7.3) sys-tem, the fluorescence intensity of gatifloxacin was linearly decreased with the concentration increase of Se(Ⅳ) in a range of 1.0×10-5-5.0×10-5 mol/L with a correlation coefficient of 0.9979(R2=0.9958) and in a range of 5.0×10-5-1.0×10-4 mol/L with a correlation coefficient of 0.9973(R2=0.9946). The detection limit of Se(Ⅳ) was 1.70×10-6 mol/L. 相似文献
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QIAN Yong-gui SUN Zi-jie HU Jing-bo ** LU Yi-qiang LI Qi-long . Department of Chemistry Beijing Normal University Beijing P. R. China . Department of Chemistry Beijing University of Science Technology Beijing P. R. China 《高等学校化学研究》2004,20(1):103-107
In a 0.02 mol/L Na2HPO4-KH2PO4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microelectrode. A sensitive reduction peak was observed. The peak potential was -0.72 V(vs.SCE), the peak current was proportional to the concentration of mitoxantrone within the ranges of 7.0×10-8-9.0×10-7 mol/L and 1.0×10-6-2.4×10-5 mol/L, with a detection limit of 4.0×10-8 mol/L. The linear correlation coefficients were 0.9994 and 0.9992, respectively. This method has been applied to the direct determination of mitoxantrone in simulated urine. The recoveries were in the range from 96.2% to 105.9%. The reduction process was a quasi-reversible one with adsorptive characteristics at the Pt/C microelectrode. The electrode reaction rate constant ks and the electron transfer coefficient α of the system were determined to be 4.5 and 0.65 s-1, respectively. The experiments showed that Pt element had surely been implanted into the surface of the carbon fiber, and the atomic Pt improved the electrocatalytic activity. The Pt/C microelectrode had a good stability and reproducibility. 相似文献
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CO2势能面和振动激发态的理论研究 总被引:1,自引:1,他引:0
采用振动自洽场-组态相互作用(SCF-CI)方法通过实验振动光谱优化了CO2分子的势能函数,由该势能函数计算得到的纯振动光谱数据与实验值相比,所有能级的误差均在4cm-1以内,均方根偏差为1.50cm-1,所预测的Π态振转光谱也与实验值很接近. 相似文献
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利用表面光电压谱及场诱导表面光电压谱研究了部分过渡金属复合氧化物的电子组态与其光伏响应的关系.结果表明,在过渡金属M(M=Cu,Co,Ni)铁酸盐系列样品中,开壳层的Cu(Ⅱ)(铁酸盐)和CO(Ⅱ)(铁酸盐)的电荷转移跃迁(CT)具有双激发态的成分,其中含有较强的低能电子跃迁;与它们相比,闭壳层的Ni(Ⅱ)铁酸盐的CT跃迁则需要较大的能量.三者的FISPS证实了它们具有不同的CT跃迁性质,为其催化反应机理研究提供了微观信息. 相似文献
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In a specimen of 70V2O5-30P2O5glass, EPR lineshapes of the vanadium 3d1 polaron have been studied between 4 and 77 K. At the lowest temperature the unpaired electron is localized at a single 51V site, and values of g=1.959, g= 1.989, A = 156.6 × 10−4 cm−1 and A=53.8 × 10−4 cm−1 have been measured. A Markovian small-step rotational diffusion model consistent with the random structure of the glass network is proposed for the polaron dynamics at the higher temperatures up to 77 K. This motion has a small activation energy barrier of 114 μeV. 相似文献
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本文根据文献[4]提出的配位场理论方法,采用SLГSГtτ方案,对晶体K2PtCl6中Re+4(5d3)和Os+4(5d4)离子能谱进行全分析,考虑了全部d3和d4组态的静电作用能,正八面体场势能和旋轨偶合作用能,计算了能级随参数变化曲线,能谱理论计算结果与文献[9-10]强场方案计算结果一致,但改正了前人对实验能谱指认不正确之处。 相似文献