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Daji W.,Sichuan UniversityChengdu | Dachuan Z.,Sichuan UniversityChengdu | Dachuan Z.,PLA Logistical Engineering University | Huafeng L.,PLA Logistical Engineering University | Guoxu C.,PLA Logistical Engineering University
Tribology Transactions | Year: 2015

Muscovite/La2O3 composite powders were prepared by ball-milling solid-state chemical reaction at room temperature. The phase composition and micromorphology of the composite powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The tribological properties of different samples were tested and compared using four-ball wear testing on an MMW-1A multifunctional friction and wear testing machine. The SEM micrography and energy spectrum of the composite powders illustrated that La2O3 particles were coated on the surface of muscovite particles. The results of the friction tests indicated that lubrication oil with muscovite/La2O3 composite powders presents better friction reducing and antiwear properties than that of the base oil, and the friction coefficients and diameters of wear scars decreased by 47.6 and 11.2% using 500SN base oil with 0.6g/L of muscovite/La2O3 composite powders as additives, respectively. The composite powders with 5 wt% La2O3 present the best comprehensive tribological properties. The micromorphology and chemical composition of the worn surface were analyzed by SEM and EDX, which confirm that the composite powders directly participate in the complicated physicochemical process of reactions on the worn surfaces, therefore improving the tribological properties of the base oil. © 2015, Copyright © Society of Tribologists and Lubrication Engineers.

Wang L.,Sichuan UniversityChengdu | Jin X.,Sichuan UniversityChengdu | Zhao X.,Sichuan UniversityChengdu | Liu D.,Sichuan UniversityChengdu | And 6 more authors.
Oral Diseases | Year: 2014

Focal dermal hypoplasia (FDH), or Goltz-Gorlin syndrome, is a rare syndrome and may result in multisystem disorders. Several reviews of FDH have been published. However, the last comprehensive review of this disorder appeared more than 20 years ago. To date, a number of new clinical manifestations have been reported and considerable knowledge has accumulated regarding etiology and pathogenetic mechanisms. The purpose of this review is to gather these more recent data and to provide organized and reliable information. So we reviewed 159 cases of FDH that had been reported from 1990 to 2012, summarized the new discoveries, and suggested a potential standard for the diagnosis of FDH. We also reported on a Chinese girl with FDH, who was clinically and histologically in accord with FDH, as an example. © 2013 John Wiley & Sons A/S.

Liu D.,Sichuan UniversityChengdu | Gou L.,Sichuan UniversityChengdu | Gou L.,University of Electronic Science and Technology of China | Ran J.,Sichuan UniversityChengdu | And 2 more authors.
Plasma Science and Technology | Year: 2015

Boron-doped nanocrystalline diamond (NCD) exhibits extraordinary mechanical properties and chemical stability, making it highly suitable for biomedical applications. For implant materials, the impact of boron-doped NCD films on the character of cell growth (i.e., adhesion, proliferation) is very important. Boron-doped NCD films with resistivity of 10-2 Ω·cm were grown on Si substrates by the microwave plasma chemical vapor deposition (MPCVD) process with H2 bubbled B2O3. The crystal structure, diamond character, surface morphology, and surface roughness of the boron-doped NCD films were analyzed using different characterization methods, such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The contact potential difference and possible boron distribution within the film were studied with a scanning kelvin force microscope (SKFM). The cytotoxicity of films was studied by in vitro tests, including fluorescence microscopy, SEM and MTT assay. Results indicated that the surface roughness value of NCD films was 56.6 nm and boron was probably accumulated at the boundaries between diamond agglomerates. MG-63 cells adhered well and exhibited a significant growth on the surface of films, suggesting that the boron-doped NCD films were non-toxic to cells.

Luo H.,Sichuan Agricultural University | Luo H.,Sichuan UniversityChengdu | Li M.,Sichuan UniversityChengdu | Xu R.,Sichuan UniversityChengdu | And 5 more authors.
Sustainable Environment Research | Year: 2012

The pollution of urban stormwater runoff discharged to river cannot be ignored. Through a mixed stormwater sampling strategy at discharge outlet adjacent to river, this study assessed the urban surface runoff pollution characteristics caused by a variety of land uses in a small urban watershed in the city of Shenzhen in China. The rainfall events were monitored from Oct. 2007 to Sep. 2008. Results show that the pollution caused by the urban surface runoff in studied area is serious and needs to be treated. The first flushes of chemical oxygen demand (COD), suspended solids (SS), biochemical oxygen demand, especially COD and SS, were apparent, but total nitrogen and total phosphorus were not evident. The event mean concentrations (EMCs) of COD were about two times of the value of the nearby cities, Macao and Zhuhai. Comparing with other counties, the EMCs of different pollutants in the studied area in Shenzhen were much higher than the values of South Korea, USA and Canada. In order to treat surface runoff pollution, the values from first 30-40% runoff volume can be considered as split-flow control criteria to enable more effective and economical design of best management practice facilities. © 2012, Chinese Institute of Environmental Engineering. All rights reserved.

Huang W.-W.,GuiZhou Power Grid Co. | Yao G.,GuiZhou Power Grid Co. | Qiu X.-Y.,Sichuan UniversityChengdu | Liu N.,Sichuan UniversityChengdu | Chen G.-T.,Sichuan UniversityChengdu
Applied Mechanics and Materials | Year: 2013

Optimization of restoration paths of power system after blackout is a multi-stage, multi-target, multi-variable combinatorial problem in the power system restoration. This paper presents a reasonable model and effectually method. The proposed model is considered as a typical partial minimum spanning tree problem from the mathematical point of view which considering all kinds of constraints. Improved data envelopment analysis (DEA) was used to get the weight which considering line charging reactive power, weather conditions, operation time and betweenness of transmission lines. The improved genetic algorithm method is employed to solve this problem. Finally, an example is given which proves the strategy of the line restoration can effectively handle the uncertainty of the system recovery process, to guarantee the system successfully restored after the catastrophic accidents. © 2013 Trans Tech Publications Ltd, Switzerland.

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