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221.
表面电沉积Ni—La2O3复合镀层的Fe26Cr1Mo不锈钢的氧化行为研究 总被引:3,自引:0,他引:3
Fe26Cr1Mo不锈钢在900℃氧化时,生成的氧化层在冷却过程中大量剥落,经表面共电沉积NiLa2O3复合镀层后,抗热循环能力明显提高。 相似文献
222.
Structural colors in nature: the role of regularity and irregularity in the structure. 总被引:10,自引:0,他引:10
Coloring in nature mostly comes from the inherent colors of materials, but it sometimes has a purely physical origin, such as diffraction or interference of light. The latter, called structural color or iridescence, has long been a problem of scientific interest. Recently, structural colors have attracted great interest because their applications have been rapidly progressing in many fields related to vision, such as the paint, automobile, cosmetics, and textile industries. As the research progresses, however, it has become clear that these colors are due to the presence of surprisingly minute microstructures, which are hardly attainable even by ultramodern nanotechnology. Fundamentally, most of the structural colors originate from basic optical processes represented by thin-film interference, multilayer interference, a diffraction grating effect, photonic crystals, light scattering, and so on. However, to enhance the perception of the eyes, natural creatures have produced various designs, in the course of evolution, to fulfill simultaneously high reflectivity in a specific wavelength range and the generation of diffusive light in a wide angular range. At a glance, these two characteristics seem to contradict each other in the usual optical sense, but these seemingly conflicting requirements are realized by combining appropriate amounts of regularity and irregularity of the structure. In this Review, we first explain the fundamental optical properties underlying the structural colors, and then survey these mysteries of nature from the viewpoint of regularity and irregularity of the structure. Finally, we propose a general principle of structural colors based on structural hierarchy and show their up-to-date applications. 相似文献
223.
HUANG Yongmin XIAO Xingqing LIU Honglai** HU Ying Department of Chemistry Lab for Advanced Material East China University of Science Technology Shanghai China 《Chinese Journal of Reactive Polymers》2006,(2)
1. INTRODUCTION The extensive applications of block copolymer have been studied in detail due to their special molecular architecture and characteristic [1,2]. Recently, many studies including theoretical analysis and experimental techniques have addressed the polymer blend system of diblock copolymer/homopolymer [3~9]. An early investigation presented a quantitative analysis of homopolymer distributions in well-ordered copolymer microdomains through mixing polystyrene (PS) or poly methyl… 相似文献
224.
225.
《Electroanalysis》2006,18(3):259-266
In this paper, a new strategy for constructing a mediator‐type amperometric hydrogen peroxide (H2O2) microbiosensor was described. An electropolymerized thionine film (PTH) was deposited directly onto a gold electrode surface. The resulting redox film was extremely thin, adhered well onto a substrate (electrode), and had a highly cross‐linked network structure. Consequently, horseradish peroxidase (HRP) was successfully immobilized on nanometer‐sized Au colloids, which were supported by thiol‐tailed groups of 11‐mercaptoundecanoic acid (11‐MUA) monolayer covalently bound onto PTH film. With the aid of the PTH mediator, HRP‐labeled Au colloids microbiosensor displayed excellent electrocatalytical response to the reduction of H2O2. This matrix showed a biocompatible microenvironment for retaining the native activity of the covalent HRP and a very low mass transport barrier to the substrate, which provided a fast amperometric response to H2O2. The proposed H2O2 microbiosensor exhibited linear range of 3.5 μM–0.7 mM with a detection limit of 0.05 μM (S/N=3). The response showed a Michaelis‐Menten behavior at larger H2O2 concentrations. The KMapp value for the biosensors based on 24 nm Au colloids was found to be 47 μM, which demonstrated that HRP immobilized on Au colloids exhibited a high affinity to H2O2 with no loss of enzymatic activity. This microbiosensor possessed good analytical performance and storage stability. 相似文献
226.
《Electroanalysis》2005,17(2):186-190
We report for the first time on the electroassisted biomimetic activation of molecular oxygen by a newly prepared electropolymerized polypyrrole‐manganese phthalocyanine film. The prepared films and their intervention in the electroassisted catalytic reduction of molecular oxygen were analyzed by cyclic voltammetry and UV‐visible spectrophotometry on optically transparent electrodes. The obtained results demonstrate the probable existence of the key‐steps responsible for the suggested formation of the highly reactive manganese oxo intermediate. 相似文献
227.
《Electroanalysis》2004,16(16):1311-1317
The determination of some toxic metals by stripping chronopotentiometry with a supporting solution having an unconventional composition has been investigated with the aim of using such components in disposable measuring cells preservable in dry state and quite ready for use, only needing addition of a small volume of sample. The new supporting solution is prepared with a solid strong acid, p‐toluenesulfonic acid, in the place of the inorganic acids commonly used to improve the cation availability. The other components are, as usual, sodium chloride, which fixes the potential of the screen‐printed silver – silver chloride reference electrode, and mercury(II) chloride as the plating agent. This supporting solution has been tested in batch measurements with the mercury film glassy carbon electrode as well as with screen‐printed carbon‐ink electrodes, either with mercury film or bare. The physical shape of the mercury layer electrolytically deposited on screen‐printed carbon‐ink electrodes from a supporting solution containing 0.1 M p‐toluenesulfonic acid and 0.1 M sodium chloride has been investigated by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) microanalysis. In chronopotentiometric stripping p‐toluenesulfonic acid performs as well as the usual inorganic strong acids, particularly in terms of sensitivity. At 0.1 mol dm?3 it proved very suitable for the determination of toxic metals, in particular lead(II), at levels down to a few μg dm?3. The overall results appear promising and can open new avenues for preparing disposable cells for on‐field stripping chronopotentiometric determination of toxic metals. 相似文献
228.
229.
丁磺酸内酯对锂离子电池性能及负极界面的影响 总被引:5,自引:0,他引:5
用循环伏安(CV)、电化学阻抗谱(EIS)、扫描电镜(SEM)、能谱分析(EDS)及理论计算等方法研究了添加剂丁磺酸内酯(BS)对锂离子电池负极界面性质的影响. 研究表明, 在初次循环过程中, BS具有较低的最低空轨道能量, 优先于溶剂在石墨电极上还原分解, 并形成固体电解质相界面膜(SEI膜). 在含BS的电解液中形成的SEI膜的热稳定性高, 在70 ℃下储存24 h后, 膜电阻和电荷迁移电阻大小基本保持不变, 而在不含BS的电解液中形成的SEI膜的热稳定性较差, 在70 ℃下储存24 h后, 膜电阻和电荷迁移电阻大小有明显的增加. 从BS对锂离子电池电化学性能影响的研究表明, 加入少量的BS能够显著提高锂离子电池的室温放电容量、低温及高温储存放电性能. 相似文献
230.
A. Al-Kahlout S. Heusing M. A. Aegerter 《Journal of Sol-Gel Science and Technology》2006,39(2):195-206
Films of NiO-TiO2 with Ni concentration of 100, 90, 87, 83, 75, 66, 50 and 33 mol% have been obtained via the sol-gel route by dip coating
technique and sintered in air between 250 and 500°C using ethanolic sols of nickel acetate tetrahydrate (Ni(CH3COO)2·4H2O) and titanium n-propoxide (Ti(O-CH(CH3)2)4) precursors. Xerogels obtai- ned by drying the sols have been studied up to 900°C by thermal analysis (DTA/TG) coupled to
mass and IR spectroscopy. The crystalline structure and morphology of the layers in the as deposited, bleached and colored
states were determined by X-ray diffractometry, scanning electron microscopy and transmission electron microscopy Their electrochromic
properties have been studied in 1 M KOH aqueous electrolyte as a function of the layer composition, thickness and sintering
temperature. Deep brown colour with reversible transmittance changes have been obtained using cycling voltammetry and chronoamperometry
processes. The best composition to get stable sols, a high reversible transmittance change and fast switching times (<10 s)
was obtained with double NiO-TiO2 layers 160 nm thick having 75% Ni molar concentration, and sintered between 300 and 350°C. The mechanism of coloration and
morphology transformation of the layer during cycling are discussed in terms of an activation and degradation period. The
results are in agreement with the accepted Bode model. 相似文献