Search results for "Scanning electron microscope"
showing 10 items of 615 documents
Grafting and characterization of dodecylphosphonic acid on copper: Macro-tribological behavior and surface properties
2013
International audience; Thin film of n-dodecylphosphonic acid (DDPA) was prepared on a copper oxide substrate via a molecular self-assembly process. The composition, structure, organization, surface energy, morphology, and electrochemical behavior of the DDPA filmwere characterized bymeans of X-ray photoelectron spectroscopic analysis (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), contact angle measurement v(CAM), microscopic observations, and electrochemistry. The friction behavior of the DDPA film adsorbed on copper oxide substrate sliding against a Si3N4 ball was examined on a linear reciprocating tribological tester. Worn surfaces of the DDPA film…
Removal of Escherichia coli from Saturated Sand Columns Supplemented with Hydrochar Produced from Maize
2014
Despite numerous studies on hydrochar use, its application in water treatment for pathogen removal remains unexplored. In this study, we evaluated the efficiency of hydrochar produced from crop residue of maize for water treatment by determining Escherchia coli breakthrough from sand columns supplemented with hydrochar. To enhance the adsorptive capacity, raw hydrochar was activated by 1 mol L⁻¹ KOH at room temperature. The experiments conducted in a 10-cm sand bed with 1.5% (w/w) activated and raw hydrochar supplements, not activated by KOH, showed 93 and 72% of E. coli removal efficiencies, respectively. Activation of KOH not only enhanced the E. coli removal but also increased the streng…
Study of the MOCVD growth of ZnO on GaAs substrates: Influence of the molar ratio of the precursors on structural and morphological properties
2007
Abstract ZnO thin films were grown by metal-organic chemical vapour deposition (MOCVD) on GaAs(100) and GaAs(111)A substrates. The growth experiments were performed at temperatures ranging from 290 to 500 ∘C and atmospheric pressure. Diethylzinc (DEZn) and tertiary butanol (tBuOH) were used as Zn and O precursors, respectively. The crystallinity of the grown films was studied by X-Ray Diffraction (XRD) and the thickness and morphology were investigated by Scanning Electron Microscopy (SEM). The influence of substrate orientation and molar ratio of the precursors on the crystalline orientation and morphology of the ZnO grown films was analysed.
Microstructural evolution of mullites produced from single-phase gels
2007
The crystalline microstructure of mullites obtained by heating monophasic gels has been investigated. Gels with alumina to silica molar ratio of 3:2 (as in secondary mullite) and 2:1 (as in primary mullite) were prepared by gelling mixtures of aluminium nitrate and tetraethylorthosilicate. Phase transformations were induced by heating the gel precursors, with different final treatment temperatures between 1173 and 1873 K. The mullites formed as a result of thermal treatment were studied by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The crystalline structure (unit-cell parameters) and microstructure were determined from X-ray diffraction pa…
Deposition of Cu Nanoparticles on the Surface of Metallic Aluminum
2012
Deposition of Cu particles by electrolysis at constant electrode potential and by internal electrolysis methods was investigated. The composition of deposited material was confirmed by optical and scanning electron microscope methods. Combination of electrolysis at constant electrode potential with internal electrolysis method was found most effective for fabrication of nanoparticle arrays. Single crystalline Cu particles are fabricated by internal electrolysis, while polycrystalline ones obtained by combined chronopotentiometric and internal electrolysis methods. The formation mechanism of Cu nanoparticles is described.
Raman spectroscopy characterization of 10-cash productions from the late Chinese emperors to the Republic
2017
[EN] The use of Raman spectroscopy for discriminating monetary emissions, a recurrent problem in much archaeological studies, is described. The method involves the record of Raman signatures of tenorite and crystalline and defective cuprite in the patina based on the idea that subtle, mint-characteristic variations in the composition and metallography of the base metal during the manufacturing process are reflected in the variation in depth of the composition and crystallinity of the corrosion patina. The technique was applied to a series of 10-cash copper coins produced around the transition between the Kuang Hsu and Hsuan Tung last Chinese emperors and the first Republic whose averaged co…
On the response of flax fiber reinforced composites under salt-fog/dry conditions: Reversible and irreversible performances degradation
2022
Abstract Despite their scarce resistance to humid or wet conditions, natural fiber reinforced composites (NFRCs) seem to be able to partially recover their performances under discontinuous exposition to marine environment. To investigate this peculiarity, flax fiber reinforced composite was at first subjected to salt-fog spray condition at 35 °C for 15 and 30 days, respectively, and then stored in ‘‘dry” condition (i.e., 50% R.H. and 22 °C) between 0 and 21 days. The performances evolution was evaluated through flexural tests, water uptake and contact angle measurements. Moreover, the morphology of fractured mechanical samples was examined by using 3D optical microscope and scanning electro…
Composite Scaffolds with a Hydrohyapatite Spatial Gradient for Osteochondral Defect Repair
2018
Osteochondral defects derived by traumatic injury or aging related disease are often associated with severe joint pain and progressive loss of joint functions for millions of people worldwide and represent a major challenge for the orthopedic community. Tissue engineering offers new therapeutic approach to repair the osteochondral defects, through the production of scaffolds manufactured to mimic their complex architecture, which consists of cartilage and bone layers. Composite scaffolds based on a PLLA polymeric matrix containing hydroxyapatite (HA) as a filler were prepared through a modified thermally induced phase separation (TIPS) protocol. A suspension was prepared by adding sieved HA…
Early bone healing around implant surfaces treated with variations in the resorbable blasting media method. A study in rabbits.
2010
Objective: this study aimed to histomorphologically and histomorphometrically evaluate the in vivo response to three variations in the resorbable blasting media (RBM) surface processing in a rabbit femur model. Study Design: screw root form implants with 3.75 mm in diameter by 8 mm in length presenting four surfaces (n=8 each): alumina-blasted/acid-etched (AB/AE), bioresorbable ceramic blasted (TCP), TCP + acid etching, and AB/AE + TCP were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The implants were placed at the distal femur of 8 New Zeland rabbits, remaining for 2 weeks in vivo. After sacrifice, the implants were nondecalcified processed to 30 …