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Wen M.,Deakin University | Wen M.,Kunming Institute of Precious Metals | Wen C.,Swinburne University of Technology | Hodgson P.D.,Deakin University | Li Y.C.,Deakin University
Tribology Letters | Year: 2012

Surface mechanical attrition treatment (SMAT), a novel surface severe plastic deformation method, was carried out for titanium (Ti) to create a gradient-structured Ti (SMAT Ti). The tribological behaviour was studied under different loads and dry sliding conditions. The results showed that the deformation layer of SMAT Ti was about 160 μm. The friction and wear results showed that the wear resistance of SMAT Ti was enhanced compared to the coarse-grained (CG) counterpart. SMAT Ti showed abrasive wear under 1 and 5 N, and exhibited abrasive and adhesive wear under 2 N. While CG Ti showed abrasive and adhesive wear under 1-2 N, and exhibited abrasive wear under 5 N for the work hardening effects. © 2011 Springer Science+Business Media, LLC. Source

Wen M.,Deakin University | Wen M.,Kunming Institute of Precious Metals | Cizek P.,Deakin University | Wen C.,Swinburne University of Technology | And 2 more authors.
Scripta Materialia | Year: 2013

A nanostructured eutectic Ag-Cu alloy with alternate Ag and Cu lamellae was processed by surface mechanical attrition treatment (SMAT). The orientation/phase distributions of the eutectic Ag-Cu before and after SMAT were investigated using transmission electron microscopy combined with automated crystal orientation mapping. After SMAT, the top surface layer was transformed into a composite with isolated Cu phase dispersed in Ag. The interphase boundaries in the top surface layer were changed from the original cube-on-cube and hetero-twin orientation relationships into general large-angle boundaries accordingly. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Wen M.,Deakin University | Wen M.,Kunming Institute of Precious Metals | Wen C.,Swinburne University of Technology | Hodgson P.,Deakin University | Li Y.,Deakin University
Corrosion Science | Year: 2012

The oxidation behaviour of a novel Ti with a nanocrystalline (NC) surface layer, made by surface mechanical attrition treatment (SMAT Ti), has been investigated in air at 500∼700 °C. SMAT Ti can react with oxygen and form oxide particles even at 500 °C, while that of coarse-grained Ti (CG Ti) is about 600 °C. Ti shows a different colour at each temperature, which is attributed to the light interference phenomena. The SMAT Ti shows a thicker, denser oxide layer as compared with that of CG Ti. It originates from the numerous grain boundaries and dislocations on the SMAT Ti surface. © 2012 Elsevier Ltd. Source

Zheng T.,Platinum Technology | He J.,Platinum Technology | Zhao Y.,Platinum Technology | Zhao Y.,Kunming Institute of Precious Metals | Xia W.,Platinum Technology
Journal of Rare Earths | Year: 2014

Precious metal-support interaction plays an important role in thermal stability and catalytic performance of the automotive exhaust catalysts. The support is not only a carrier for active compounds in catalysts but also can improve the dispersion of precious metals and suppress the sintering of precious metals at high temperature; meanwhile, noble metals can also enhance the redox performance and oxygen storage capacity of support. The mechanism of metal-support interactions mainly includes electronic interaction, formation of alloy and inward diffusion of metal into the support or covered by support. The form and degree of precious metal-support interaction depend on many factors, including the content of precious metal, the species of support and metal, and preparation methods. The research results about strong metal-support interaction (SMSI) gave a theory support for developing a kind of new catalyst with excellent performance. This paper reviewed the interaction phenomenon and mechanism of precious metals (Pt, Pd, Rh) and support such as Al 2O3, CeO2, and CeO2-based oxides in automotive exhaust catalysts. The factors that affect SMSI and the catalysts developed by SMSI were also discussed. © 2014 The Chinese Society of Rare Earths. Source

Xie M.-J.,Yunnan University | Yang X.-D.,China Pharmaceutical University | Liu W.-P.,Kunming Institute of Precious Metals | Yan S.-P.,Nankai University | Meng Z.-H.,Kunming Hospital of Population and Health
Journal of Inorganic Biochemistry | Year: 2010

A new insulin-enhancing oxovanadium complex 5-chloro-salicylaldhyde ethylenediamine oxovanadium (V) ([V2O2(μ-O)2L2]) has been synthesized. The complex was characterized by a variety of physical methods, including X-ray crystallography. The X-ray diffraction analysis show a dinuclear complex of two six-coordinate vanadium centers doubly bridged by the oxygen atoms of the Schiff base ligand with a V2O2 diamond core. The complex was administered intragastrically to STZ-diabetic rats for 2weeks. The biological activity results show that the complex at the dose of 10.0 and 20.0mgVkg-1, could significantly decrease the blood glucose level and ameliorate impaired glucose tolerance in STZ-diabetic rats. That results suggested that the complex exerts an antidiabetic effect in STZ-diabetic rats. Furthermore, the complex ([V2O2(μ-O)2L2]) had permeability above 10-5cm/s. The experimental results suggested that the vanadium complex permeates via a passive diffusion mechanism. It was also suggested the complex with salen-type ligands has good lipophilic properties and better oral administration. The cytotoxicity of the complex ([V2O2(μ-O)2L2]) on Caco-2 cells was measured by a decrease of cell viability using the MTT assay suggesting that the chlorine atom at C4 of complex [V2O2(μ-O)2L2] increased cytotoxicity for vanadium complexes. © 2010 Elsevier Inc. Source

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