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排序方式: 共有805条查询结果,搜索用时 46 毫秒
61.
采用氯盐溶液和硫酸盐溶液浸泡镁水泥钢筋混凝土构件,使构件中的涂层钢筋加速锈蚀,并利用电化学工作站进行电化学试验;以腐蚀电流密度作为钢筋耐久性退化指标,建立一元Wiener过程预测模型进行钢筋腐蚀寿命预测.结果 表明:在氯盐溶液环境下,镁水泥混凝土构件中的钢筋受腐蚀问题较之硫酸盐溶液环境更为突出,且涂层在2种盐溶液环境中均对钢筋起到了较好的防护效果;在氯盐溶液环境中,涂层钢筋在1500 d附近进入中等腐蚀阶段,在硫酸盐溶液环境中,涂层钢筋在22000 d进入中等腐蚀阶段. 相似文献
62.
In this paper, we employed the as‐prepared TiO2/C core/shell nanoarrays (TiO2/C) obtained by a facile thermal evaporation method as a three‐dimensional (3D) architecture to support Pt nanoparticles through an optimized electrodeposition process. The morphology and structure of the as‐prepared electrode are characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Its catalytic performance towards H2O2 electroreduction in basic medium is evaluated by linear sweep voltammetry (LSV) and chronoamperometry (CV). Results revealed that the electrode exhibits significantly high catalytic activity. The current density reached –0.172 A cm−2 in 1 mol dm−3 NaOH and 0.5 mol dm−3 H2O2 at –1.1 V (vs. Ag/AgCl). This high performance might be due to the 3D electrode architecture inheriting the high electronic conductivity from carbon shell and providing a short pathway for the ion diffusion, and the using of Pt owning an excellent catalytic activity. 相似文献
63.
Junfei Ou Jinqing Wang Jinfang Zhou Sheng Liu Yuanlie Yu Xianjuan Pang Shengrong Yang 《Progress in Organic Coatings》2010
Metal aluminum (Al) is being widely used in industry and can be easily corroded in severe conditions. Recently, dopamine has been demonstrated to be an effective adhesive molecular that can be attached to virtually all material surfaces to form stable polydopamine coating (PDAc), exhibiting promising prospects in many fields. In this work, to improve the anti-corrosion performance of Al sheet, a novel polydopamine-based 3-layer organic coating has been constructed by a multi-step self-assembly technique for the first time. In brief, a self-assembled monolayer of (3-mercaptopropyl)trimethoxysilane (coded as MPTS-SAM) was firstly prepared for enhancing the adhesion between the PDAc and the Al substrate. Subsequently, a PDAc was assembled onto the Al substrate by a simple immersion into the dopamine hydrochloride solution at a pH of 8.5. At last, a layer of tetradecanoyl chloride was grafted onto the PDAc surface through amidation, which could apparently slow down the water diffusion to the interface of PDAc and Al for its prominent hydrophobicity. Corrosion resistance of the synthesized coating in NaCl solution was evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) measurement, respectively. As results show, PDAc on bare Al can protect the substrate from corrosion to a certain extent. Significantly, after being mediated by MPTS-SAM underlayer and covered by tetradecanoyl chloride outer layer, the anti-corrosion capability of the coating has been improved markedly. 相似文献
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66.
A new approach for nonenzymatic glucose sensing, based on a simple modification of epoxy-silver surfaces deposited on the tip of commercial copper electric wires, is presented. Palladium was galvanically displaced on the surface of the epoxy-silver surface in order to obtain metal nanoparticles that act as catalyst for the direct oxidation of glucose. Scanning electron microscopy revealed the formation of the metal nanoparticles. X-ray photoelectron spectroscopy confirmed the metallic nature of the formed nanostructures on the surface. Electrochemical characterization and calibration of the palladium-modified epoxy-silver electrode is reported, obtaining a linear range of 1–20 mM for the detection of glucose with low interference of ascorbic acid and uric acid. A simple 3-step coulometry was used as the detection technique. The developed sensing material is believed to be a great candidate for integration in small devices for clinical essays, due to the simplicity and cost effectiveness of the presented approach, compared to the state-of-the-art devices reported recently in the literature. Simplicity in the coulometry determinations makes these Pd-modified epoxy-silver sensors a good candidate for easy glucose determinations. 相似文献
67.
Tzu Hui SeahAuthor VitaeMartin PumeraAuthor Vitae 《Sensors and actuators. B, Chemical》2011,156(1):79-83
The fabrication and attractive sensing and biosensing performance of platelet graphite nanofibers/polysulfone (PGNF/PSf) composite nanomaterials is described. The PGNF/PSf nanocomposites were fabricated by facile phase-inversion method. Their electrochemical performance was compared to the one of carbon nanotubes/PSf and graphite microparticles/PSf composite. It was clearly demonstrated that PGNF/PSf provides superior voltammetric and amperometric performance for sensing and biosensing over those two other sp2 carbon materials. This can be attributed to the unparallel amount of electroactive edge sites on PGNF in which electroactivity is not impaired by the polysulfone binder. PGNF/PSf/glucose oxidase nanobiocomposite was prepared and used for proof-of-concept biosensing of glucose. 相似文献
68.
Isabella Chiarotto 《Electrochimica acta》2009,54(5):1638-1644
An electrochemical procedure for the N-acylation of chiral oxazolidin-2-ones, in the absence of volatile molecular organic solvents, has been set up via electrolyses of ionic liquid [bmim]BF4 containing oxazolidin-2-ones followed by addition of saturated or unsaturated anhydrides. N-acyloxazolidin-2-ones were isolated in good to elevated yields. The electrochemically induced N-acylation of chiral oxazolidin-2-ones occurs with total retention of the absolute configuration of all the chiral atoms. The electrogenerated carbene (1-butyl-3-methyl-1H-imidazol-2-ylidene) has been indicated as the base involved in the deprotonation of chiral oxazolidin-2-ones. 相似文献
69.
A. Meléndez-Ceballos S.M. Fernández-Valverde C. Barrera-Díaz V. Albin V. Lair A. Ringuedé M. Cassir 《International Journal of Hydrogen Energy》2013
One of the main issues for optimizing the molten carbonate fuel cell (MCFC) is the control of the corrosion and dissolution of the state-of-the-art porous nickel oxide cathode. A protective coating constituted by more stable oxides seems to be the best solution. In this paper, very thin layers of TiO2 (50 and 300 nm) are processed by a sequential CVD technique, Atomic Layer Deposition (ALD), which produces high quality, homogeneous and conformal layers. Structural, morphological and electrochemical behaviors of TiO2-coated samples are tested in a Li2CO3–K2CO3 (62:38 mol%) eutectic melt under a standard cathode atmosphere: CO2/air (70:30 bar%). Ni solubility is determined by ICP-AES. The protective role of TiO2 layers and the consequent decrease in Ni solubility have been clearly evidenced. 相似文献
70.
The aim of the work was to develop the chamber to be used in biomechanical, electrochemical and electrophysiological measurements in functional segments of peripheral nerves, when electrical stimulating pulses are selectively applied to preselected locations along the nerve and neural responses are measured. 相似文献