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101.
A simple method is developed to synthesize gram quantities of uniform Ge nanowires (GeNWs) by chemical vapor deposition on preformed, monodispersed seed particles loaded onto a high surface area silica support. Various chemical functionalization schemes are investigated to passivate the GeNW surfaces using alkanethiols and alkyl Grignard reactions. The stability of functionalization against oxidation of germanium for various alkyl chain lengths is elucidated by X-ray photoelectron spectroscopy. Among all schemes tested, long chain alkanethiols (> or = C12) are found to impart the most stable GeNW passivation against oxidation upon extended exposure to ambient air. Further, the chemically functionalized oxidation-resistant nanowires are soluble in organic solvents and can be readily assembled into close-packed Langmuir-Blodgett films potentially useful for future high performance electronic devices. 相似文献
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不同波长紫外光照下纳米TiO2薄膜的光致亲水性与循环伏安行为 总被引:6,自引:1,他引:6
通过溶胶-凝胶方法分别在ITO和玻璃表面制备了纳米TiO_2薄膜,研究了纳米 TiO_2薄膜在254及365nm的紫外光照射下的循环伏安行为和光致超亲水性。在紫外 光的照射下,TiO_2薄膜电极可表现出两个光电化学过程,纳米TiO_2薄膜的光致超 亲水性转变及两个光电化学过程的速率均取决于紫外光的波长,原因在于纳米 TiO_2薄膜对两种波长的光的吸收率和光子的能量不同。提出了光电化学过程的机 理,认为紫外光照射下纳米TiO_2薄膜的超亲水性变化与产生Ti~(3+)的过程引起的 表面微观结构变化存在的一定的内在联系。 相似文献
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Inside Cover: High‐Nuclear Organometallic Copper(I)–Alkynide Clusters: Thermochromic Near‐Infrared Luminescence and Solution Stability (Chem. Eur. J. 49/2016) 下载免费PDF全文
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Dr. Xisen Hou Prof. Chenfeng Ke Dr. Yu Zhou Dr. Zhuang Xie Dr. Ahmed Alngadh Dr. Denis T. Keane Dr. Majed S. Nassar Dr. Youssry Y. Botros Prof. Chad A. Mirkin Prof. J. Fraser Stoddart 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(35):12301-12306
Covalent and supramolecular polymerizations, both of which offer their own unique advantages, have emerged as popular strategies for making artificial materials. Herein, we describe a concurrent covalent and supramolecular polymerization strategy—namely, one which utilizes 1) a bis‐azide‐functionalized diazaperopyrenium dication that undergoes polymeriation covalently with a bis‐alkyne‐functionalized biphenyl derivative in one dimension as a result of a rapid and efficient β‐cyclodextrin(CD)‐accelerated, cucurbit[6]uril(CB)‐templated azide–alkyne cycloaddition, while 2) the aromatic core of the dication is able to dimerize in a criss‐cross fashion by dint of π–π interactions, enabling simultaneous supramolecular assembly, resulting in an extended polymer network in an orthogonal dimension. 相似文献
107.
Laser-induced breakdown spectroscopy(LIBS) is used to determine the total nitrogen(TN) and total phosphorus(TP) in soil.Quantitative determinations are conducted using the line intensity of the analyte element and element concentration.Calibration models are obtained using ten samples for TN and seven samples for TP.The rest samples are used to validate the results.Strong linear correlations are obtained from the determined TN and TP concentrations.LIBS is a powerful tool for analyzing soil samples to determine nutrient elements by selecting calibration and validation samples with similar matrix composition. 相似文献
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Designs, Codes and Cryptography - The discrete logarithm problem arises from various areas, including counting the number of points of certain curves and diverse cryptographic schemes. The... 相似文献
109.
As one of the biological endogenous pigments, biliverdin (BV) and its dimethyl ester (BVE) have extremely weak fluorescence in solution with quantum yield less than 0.01%. However, the situation reverses with the addition of zinc ions. The strength for fluorescence of BVE-Zn\begin{document}$ ^{2+} $\end{document} complex is greatly enhanced and fluorescence quantum yield can increase to \begin{document}$ \sim $\end{document} 5%. Herein, we studied ultrafast excited state dynamics of BVE-Zn\begin{document}$ ^{2+} $\end{document} complex in ethanol, \begin{document}$ n $\end{document} -propanol, and DMSO solutions in order to reveal the mechanism of fluorescence quantum yield enhancement. The results show that BVE can form a stable coordination complex with zinc with 1:1 stoichiometry in solution. BVE is structurally and energetically more stable in the complex. Using picosecond time-resolve fluorescence and femtosecond transient absorption spectroscopy, we show that smaller non-radiative rate constant of BVE-Zn\begin{document}$ ^{2+} $\end{document} complex in DMSO is the key to increasing its fluorescence quantum yield and the excited state decay mechanism is also revealed. These results provide valuable information about the fluorescence property change after BVE binding to metal ions and may provide a guidance for the study of phytochromes or other fluorescence proteins in which BV/BVE acts as chromophores. 相似文献
110.