Search

Your search keyword '"Zhan, Wenyi"' showing total 16 results
Start Over Author "Zhan, Wenyi"
16 results on '"Zhan, Wenyi"'

7. Relationship among Thermodynamic, Growth Kinetics, and Microstructure Characterization of the Simple and Silicon‐Modified Aluminide Coating on Ni‐based Superalloy.

Author

Dai, Yanzhang, Zou, Jianpeng, Ning, Xiaozhi, Wei, Hongming, Zhan, Wenyi, and Li, Feiyang

Subjects
NICKEL alloys, HEAT resistant alloys, SURFACE coatings, MICROSTRUCTURE, CRYSTAL grain boundaries, PARTIAL pressure
Abstract

This research investigates the effects of pack cementation parameters on the thermodynamics, growth kinetics, and microstructure of the simple and silicon‐modified aluminide coatings on the IN718 superalloy. The growth kinetic modelling of the aluminide coating, activated by NH4Cl, is established as h=174252.02T12WAl12WNH4Cl12t12exp-8306.5T ${h={{174252.02}\over{{T}^{{{1}\over{2}}}}}{W}_{Al}^{{{1}\over{2}}}{W}_{NH4Cl}^{{{1}\over{2}}}{t}^{{{1}\over{2}}}exp\left({{-8306.5}\over{T}}\right)}$. further optimizing the kinetics modelling that includes both CaCl2 activator or the mixture of CaCl2 and NH4Cl. The results showed that NH4Cl as an activator generated a higher equilibrium partial pressure of halides, which enhanced the deposition efficiency of active Al atoms and facilitated the significant precipitation of Cr‐rich carbides. Additionally, part of the CaCl2 substitute NH4Cl could maintain a high coating growth rate and reduce the hazards. Adding Si element preferentially combines with Cr formed the Cr9.1Si0.9 phase along grain boundaries, which blocked the inner‐diffusion channels of Al atoms and reduced the thickness of the silicon‐modified aluminide coating compared to simple aluminide coating. These researches revealed the relationship among the thermodynamics, growth kinetics, and microstructure of simple and silicon‐modified aluminide coatings. The thickness and microstructure of coatings can be effectively regulated by adjusting the powder composition, content, and process parameters to achieve precise control. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

14. Application of a mercapto-terminated binuclear Cu(II) complex modified Au electrode to improve the sensitivity and selectivity for dopamine detection

Author

Shu Tian, Zhan Wenyi, Guoqing Jiang, Guomin Jiang, Gu Xuefang, and Tingting Chen

Subjects
Detection limit, Chemistry, Inorganic chemistry, Metals and Alloys, Condensed Matter Physics, Electrochemistry, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Dielectric spectroscopy, Monolayer, Electrode, Materials Chemistry, Differential pulse voltammetry, Electrical and Electronic Engineering, Cyclic voltammetry, Selectivity, Instrumentation
Abstract

A new mercapto-terminated binuclear Cu(II) complex, [Cu2Cl2(mtboc)2(C12H8N2)2] [mtboc =2-(methylthio)benzo[d]oxazole-5-carboxylic acid] (Cu2), was synthesized and characterized by single-crystal X-ray diffraction studies. The Cu2 complex was then immobilized on the surface of Au electrodes through S Au bonds to form a self-assembled monolayer. The electrochemical properties of the as-prepared Cu2- modified Au electrode (Au/Cu2) were investigated using cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry (DPV). Moreover, as a biomimetic sensor for the determination of dopamine (DA) and uric acid (UA), the Au/Cu2 electrode exhibited excellent electrocatalytic activity for the oxidation of DA with a faster electron-transfer rate (6.61 s−1). The DPV technique was used for the trace determination of DA. The dependence of current vs. concentration was linear from 0.2 to 30 μM with a regression coefficient of 0.9975, and the detection limit of DA was ∼ 0.08 μM. Furthermore, the modified electrode clearly separated the DA signal from the interference effect of UA, thus realizing the simultaneous detection of DA and UA. Finally, the method was applied to the selective and precise analysis of DA in commercial injection and urine samples.

Published
2015

15. Detection of dopamine on a mercapto-terminated hexanuclear Fe(III) cluster modified gold electrode

Author

Zhan Wenyi, Shu Tian, Gu Xuefang, Tingting Chen, Sijie Wu, Guoqing Jiang, Xuan Li, and Guomin Jiang

Subjects
Detection limit, Models, Molecular, Calibration curve, Chemistry, Diffusion, Dopamine, Iron, Inorganic chemistry, Analytical chemistry, Molecular Conformation, Analytical Chemistry, chemistry.chemical_compound, Dielectric Spectroscopy, Electrode, Pyridine, medicine, Cluster (physics), Electrochemistry, Organometallic Compounds, Molecule, Gold, Electrodes, medicine.drug
Abstract

In this study, a novel mercapto-terminated hexanuclear iron(III) cluster [Fe6O2(OH)2(O2CC6H4SCH3)10(hep)2]·CH3CN·CH2Cl2 [hep=2-(2-hydroxyethyl) pyridine] (Fe6) modified Au electrode was fabricated, having highly sensitive dopamine (DA) detection capabilities. In such Fe6 molecules, 10 thiomethyl groups are located at the periphery of the cluster, which enable the Fe6 molecules to self-assemble onto the surface of Au electrodes through the formation of Au–S bonds. The as-prepared Fe6-modified Au electrode (Au/Fe6) exhibits excellent electrocatalytic activity for the oxidation of dopamine (DA) in PBS with a diffusion coefficient of 3.12×10−5 cm2/s. Using the square wave voltammetry (SWV) technique, the calibration curve for DA determination was obtained in the range of 0.2 to 30 μM, and the detection limit for DA was ~0.07 μM. Furthermore, the modified electrode can accurately separate the DA signal from the interfering effect of uric acid (UA), thus providing simultaneous detection of DA and UA in their binary mixtures. This electrode can be reliably used to assay DA in its real drug composition.

Published
2014

Catalog

Books, media, physical & digital resources
See catalog results