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EDX Analysis (edx + analysis)
Selected AbstractsIn Vitro Characteristics of Surface-Modified Biphasic Calcium Phosphate/Poly(L -Lactide) BiocompositeADVANCED ENGINEERING MATERIALS, Issue 4 2010Weizhong Yang Abstract Surface-modified biphasic calcium phosphate (BCP)/poly(L -lactide) (PLLA) biocomposite is shown to have improved microstructure and mechanical properties compared to the unmodified system. In vitro biodegradation and bioactivity of the composite are investigated in simulate body fluid for up to four weeks. Weight changes of the samples and the pH changes of the SBF are recorded. Surface properties of the composite after immersion are characterized by XRD, SEM and EDX analyses. Cyto-compatibility was determined by MTT assay with L929 mouse fibroblasts. The difference of the degradation behavior between modified BCP/PLLA and the reference unmodified composite are investigated, and mBCP/PLLA composite is proved to be a better as a scaffold material. The surface formed bio-apatite layer after immersion shows the excellent bioactivity of the mBCP/PLLA composite. L929 cells show a high growth rate and proliferation, demonstrating the good cytocompatibility of mBCP/PLLA composite. [source] Synthesis, Structure and Electrical Properties of Mo-doped CeO2,Materials for SOFCsFUEL CELLS, Issue 5 2009Q. Li Abstract In this paper, we report the synthesis, structure and electrical conductivity of Mo-doped compounds with a nominal chemical formula of Ce1,xMoxO2+, (x,=,0.05, 0.07, 0.1) (CMO). The formation of fluorite-like structure with a small amount of Ce8Mo12O49 impurity (JCPDS Card No. 31-0330) was confirmed using a powder X-ray diffraction (PXRD). The fluoride-type structure was retained under wet H2 and CH4 atmospheres at 700 and 800,°C, while diffraction peaks due to metal Mo were observed in dry H2 under the same condition. AC impedance measurements showed that the total conductivity increases with increasing Mo content in CMO, and among the investigated samples, Ce0.9Mo0.1O2+, exhibited the highest electrical conductivity with a value of 2.8,×,10,4 and 5.08,×,10,2 S cm,1 at 550,°C in air and wet H2, respectively. The electrical conductivity was found to be nearly the same, especially at high temperatures, in air, O2 and N2. Chemical compatibility of Ce0.9Mo0.1O2+, with 10,mol-% Y2O3 stabilised ZrO2 (YSZ) and Ce0.9Gd0.1O1.95 (CGO) oxide ion electrolytes in wet H2 was evaluated at 800,1,000,°C, using PXRD and EDX analyses. PXRD showed that CMO was found to react with YSZ electrolyte at 1,000,°C. The area specific polarisation resistance (ASPR) of Ce0.9Mo0.1O2+, on YSZ was found to be 8.58,ohm,cm2 at 800,°C in wet H2. [source] Electrospun Hybrid Nanofibers Based on Chitosan or N -Carboxyethylchitosan and Silver NanoparticlesMACROMOLECULAR BIOSCIENCE, Issue 9 2009Hristo Penchev Abstract Hybrid nanofibers from chitosan or N -carboxyethylchitosan (CECh) and silver nanoparticles (AgNPs) were prepared by electrospinning using HCOOH as a solvent. AgNPs were synthesized in situ in the spinning solution. HCOOH slowed down the cross-linking of the polysaccharides with GA enabling the reactive electrospinning in the presence of poly(ethylene oxide) (PEO). EDX analyses showed that AgNPs are uniformly dispersed in the nanofibers. Since AgNPs hampered the cross-linking of chitosan and CECh with GA in the hybrid fibers, the imparting of water insolubility to the fibers was achieved at a second stage using GA vapors. The surface of chitosan/PEO/AgNPs nanofibers was enriched in chitosan and 15 wt.-% of the incorporated AgNPs were on the fiber surface as evidenced by XPS. [source] Technological Characterization of Campanian Pottery of Type A, B and C and of Regional Products from Ancient Calabria (Southern Italy)ARCHAEOMETRY, Issue 1 2001P. Mirti Sherds of Campanian pottery were studied by SEM-EDX. SEM images show that slips of Campana C are scarcely sintered and are thicker than the well vitrified coatings of Campana A and B and imitations of Campana B. Slips of products with a grey slip on a grey body are very thin and well vitrified. EDX analyses indicate that slips are richer in aluminium and iron, and poorer in silicon and calcium, with respect to the bodies. Higher potassium is also found in all of the coatings except those of Campana A. Here relatively high sodium makes the total alkalis comparable with those of the other products, except Campana C, where it is somewhat lower. Measurement of thermal expansion and X-ray powder diffractograms suggest that firing temperatures were mostly in excess of 900°C, but some samples of Campana C seem to have been fired below 800°C. [source] Frameworks by Solvent-Free Synthesis of Rare Earth Chlorides with Molten 1,3-Benzodinitrile and Tailoring of the Particle Size: ,3[LnCl3{1,3-C6H4(CN)2}], Ln = Y, Dy, Ho, Er, YbEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2010Christoph J. Höller Abstract The solvent-free melt reactions of anhydrous rare earth trichlorides with molten 1,3-benzodinitrile [1,3-C6H4(CN)2, C8H4N2] result in isophthalonitrile frameworks of the rare earth elements. The particle size of the products can bevaried from the millimeter to the nanometer scale (down to 50,400 nm) depending on the synthesis conditions. Thus, these network structures are among the very few coordination polymers that can be synthesized as nanoparticles. A constitution of 1:1 concerning LnCl3/1,3-C6H4(CN)2 is found for Y (1), Dy (2), Ho (3), Er (4), and Yb (5) in isotypic,3[LnCl3{1,3-C6H4(CN)2}]. The ligand 1,3-C6H4(CN)2 functions both as chemical scissors and replaces chloride linkages by degrading the rare earth chloride structures, and subsequently forms new 3D-framework structures. They consist of strands of chlorido-coordinated lanthanide atoms, which are linked in two dimensions by 1,3-C6H4(CN)2 molecules. Compounds 1,5 were obtained as single crystals from the melt reaction, and their crystal structures were determined by single-crystal X-ray analysis. They can also be obtained as nanocrystalline materials from a ball mill treatment, identified by electron microscopy (REM) and EDX analysis. [source] Syntheses of Porous Self-Supporting Metal-Nanoparticle Assemblies with 3D Morphologies Inherited from Biosilica Templates (Diatom Frustules)ADVANCED MATERIALS, Issue 4 2009Zhihao Bao Porous 3D metal-nanoparticle assemblies with selectable morphologies are synthesized. Biosilica templates (diatom frustules) are first converted into silicon replicas via magnesiothermic reduction. Electroless metal deposition, followed by silicon dissolution, then yields metal-nanoparticle assemblies with the 3D template morphology (figure reveals a silver assembly; inset images reveal internal features after partial ion milling and EDX analysis). [source] High-Temperature Instability of Li- and Ta-Modified (K,Na)NbO3 PiezoceramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Yongli Wang This paper addresses the high-temperature instability of Li- and Ta-modified (K,Na)NbO3 piezoceramics. The grains with abnormal size evolve out of the fine matrix grains during high-temperature annealing. They are found to be precipitates with a tetragonal tungsten bronze structure, which result from the volatilization and segregation of the alkali metal elements. With the growth of the abnormal grains the composition of the perovskite matrix phase also changes remarkably, as has been suggested by EDX analysis (for Na) and electric measurements (for Li). These variations lead to a large increase in the tetragonal/orthorhombic phase transition temperature and appreciable variations in the dielectric, ferroelectric, and piezoelectric properties of the ceramic samples. Control of the volatilization of the alkali metal elements can efficiently depress the abnormal grain growth and the compositional segregation. [source] Fibrous and Helical Calcite Crystals Induced by Synthetic Polypeptides Containing O -Phospho- L -Serine and O -Phospho- L -ThreonineMACROMOLECULAR BIOSCIENCE, Issue 1 2008Shinya Hayashi Abstract The modification of CaCO3 crystal growth by synthetic L -Ser(PO3H2) and L -Thr(PO3H2) containing polypeptides is described. The amino acids Gly, L -Glu, L -Asp, L -Ser, L -Ala, and L -Lys induced rhombohedral calcite with a rough surface. Dipeptides, Xaa- L -Ser(PO3H2) (Xaa,=,Gly, L -Glu, L -Asp, L -Ser, L -Ala and L -Lys) induced vaterite crystals in the lower [Ca2+]. On the other hand, L -Ser(PO3H2)-containing polypeptides formed spherical vaterite and fibrous calcite. The characteristic helical calcite was found in the presence of copoly[L -Ser(PO3H2)75L -Asp25] or poly[L -Ser(PO3H2)3,L -Asp]. Fibrous calcite, spherical vaterite, and helical calcite crystals were subjected to XRD and EDX analysis. XRD revealed the specific faces of these crystals. EDX spectra and surface analysis visualized the localization of the polypeptides and CaCO3 components. Together with TEM and SAED data, we propose hypothetical growth mechanisms for the fibrous and helical calcite crystals. [source] Calcium Phosphate Crystallization on Electrospun Cellulose Non-Woven Fabrics Containing Synthetic Phosphorylated PolypeptidesMACROMOLECULAR MATERIALS & ENGINEERING, Issue 5 2009Shinya Hayashi Abstract The preparation of electrospun non-woven fabrics composed of cellulose and synthetic phosphorylated polypeptides, copoly[Ser(PO3H2)XAspY]s (X:Y,=,100:0, 75:25, 50:50, 25:75), is described. The non-wovens were subjected to an alternate immersion in CaCl2 and Na2HPO4 solutions to induce crystallization of calcium phosphate. The deposited calcium phosphate crystals were analyzed by means of EDX analysis and WXRD. The amounts of calcium phosphate deposition are greater for the cellulose non-woven fabrics containing copoly[Ser(PO3H2)XAspY] than those of cellulose-only non-woven fabrics. These results indicate that copoly[Ser(PO3H2)XAspY] can entrap Ca2+ ions around the fine fiber matrix to accelerate crystallization of the calcium phosphate. [source] Chemical and morphological features of dental composite resin: Influence of light curing units and immersion mediaMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2010Patrícia Aleixo Dos Santos Abstract Aims: The study evaluated the influence of light curing units and immersion media on superficial morphology and chemistry of the nanofilled composite resin Supreme XT (3M) through the EDX analysis and SEM evaluation. Light curing units with different power densities and mode of application used were XL 3000 (480 mW/cm2), Jet Lite 4000 Plus (1230mW/cm2), and Ultralume Led 5 (790 mW/cm2) and immersion media were artificial saliva, Coke®, tea and coffee, totaling 12 experimental groups. Specimens (10 mm × 2 mm) were immersed in each respective solution for 5 min, three times a day, during 60 days and stored in artificial saliva at 37°C ± 1°C between immersion periods. Topography and chemical analysis was qualitative. Findings: Groups immersed in artificial saliva, showed homogeneous degradation of matrix and deposition of calcium at the material surface. Regarding coffee, there was a reasonable chemical degradation with loss of load particles and deposition of ions. For tea, superficial degradation occurred in specific areas with deposition of calcium, carbon, potassium and phosphorus. For Coke®, excessive matrix degradation and loss of load particles with deposition of calcium, sodium, and potassium. Conclusion: Light curing units did not influence the superficial morphology of composite resin tested, but the immersion beverages did. Coke® affected material's surface more than did the other tested drinks. Microsc. Res. Tech., 2010. © 2009 Wiley-Liss, Inc. [source] Enhanced Bactericidal Activity of Modified Titania in Sunlight against Pseudomonas aeruginosa, a Water-Borne PathogenPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2010S. Swetha Photocatalyst-mediated inactivations generate reactive oxygen species and OH radicals, which induce oxidative destruction of membrane integrity, causing damage to membrane phospholipids of gram negative bacteria like Pseudomonas aeruginosa. Nanosized TiO2 was synthesized by gel to crystalline conversion and Zr-doped TiO2 was synthesized by pulverization using appropriate precursor. The doped nanocrystals retained the anatase phase with a marginal increase in crystallite size, averaging at 25 nm. SEM,EDX analysis of the doped sample depicts the substantial growth of grain size with 1.33 atomic weight % of zirconium. The created electron states in the doped sample act as charge carrier traps suppressing recombination which later detraps the same to the surface of the catalyst causing enhanced interfacial charge transfer. Zr-doped TiO2 at the molecular scale exhibits better photocatalytic activity with lower bandgap energy that can respond to visible light. The redshift caused by the dopants in absorption spectra of TiO2 facilitated the nonintrinsic sample to exhibit nearly 2-fold enhancement of photoinactivation in sunlight. Extent of photoinactivation of P. aeruginosa was observed to be complete (100%) within 150 min of sunlight exposure in the presence of modified TiO2. [source] Space group and atomic structure determination of a nano-sized ordered phase derived from a f.c.c. structure in maraging steel 12Cr,9Ni,4Mo,2Cu using transmission electron microscopyACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2003Ping Liu The unique properties of maraging steel Sandvik 1RK91 were attributed to unique precipitation: a nano-sized L phase in addition to the quasi-crystalline R, phase, which differs from any precipitation system in conventional maraging steels. The L phase was observed after ageing at either 748 or 823,K. It has flake morphology with dimensions ,100 × 500 × 500,Å. In the present study the structure of the L phase was examined using convergent-beam electron diffraction (CBED), energy-dispersive X-ray analysis (EDX) and high-resolution electron microscopy (HREM). The L phase could be described as Ti19Fe9Mo9Al8Cr5Ni50 or simply M50Ni50 (M = Ti, Fe, Mo, Al and Cr). The L phase is isostructural to FeNi. Its crystal structure was determined to have the ordered structure of the uAu-I type (L10, P4/mmm, a = 3.52, c = 3.63,Å and Z = 2) with two Ni atoms at ½ 0 ½ and 0 ½½, and two M atoms at 0 0 0 and ½½ 0. The crystal structure of the L phase can also be described using a primitive tetragonal cell and lattice parameters: a = 2.49 and c = 3.63,Å, Z = 1. The volume of the primitive tetragonal unit cell is 22.5,Å3 and the density is ,6.98,g,cm,3. The present study has demonstrated the possibility of determining the structure of an extremely small crystal by utilizing the information from CBED, EDX analysis and HREM. [source] Deposition of copper-doped iron sulfide (CuxFe1,xS) thin films using aerosol-assisted chemical vapor deposition techniqueAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2010Sujit D. Disale Abstract Copper-doped iron sulfide (CuxFe1,xS, x = 0.010,0.180) thin films were deposited using a single-source precursor, Cu(LH)2Cl2 (LH = monoacetylferrocene thiosemicarbazone), by aerosol-assisted chemical vapor deposition technique. The Cu-doped FeS thin films were deposited at different substrate temperatures, i.e. 250, 300, 350, 400 and 450 °C. The deposited thin films were characterized by X-ray diffraction (XRD) patterns, Raman spectra, scanning electron microscopy, energy dispersive X-ray analysis (EDX) and atomic force microscopy. XRD studies of Cu-doped FeS thin films at all the temperatures revealed formation of single-phase FeS structure. With increasing substrate temperature from 250 to 450 °C, there was change in morphology from wafer-like to cylindrical plate-like. EDX analysis showed that the doping percentage of copper increased as the substrate temperature increased from 250 to 450 °C. Raman data supports the doping of copper in FeS films. Copyright © 2010 John Wiley & Sons, Ltd. [source] ANALYSIS OF NASRID POLYCHROME CARPENTRY AT THE HALL OF THE MEXUAR PALACE, ALHAMBRA COMPLEX (GRANADA, SPAIN), COMBINING MICROSCOPIC, CHROMATOGRAPHIC AND SPECTROSCOPIC METHODS,ARCHAEOMETRY, Issue 4 2009C. CARDELL The pigments, binders and execution techniques used by the Nasrids (1238,1492) to polychrome carpentry in the Hall of the Mexuar Palace at the Alhambra (Granada, Spain) were studied using optical microscopy, scanning electron microscopy with EDX analysis, selective staining techniques and gas chromatography , mass spectrometry. This pioneering investigation presents the first results of a research project devoted to filling gaps in the knowledge of Nasrid art, traditionally approached by stylistic studies. Moreover, it is essential for the polychromy conservation of the studied artworks, and will help to clarify historical and painting uncertainties in the Alhambra monument. The palette consists of a limited range of colours: white (lead-base pigment), red (cinnabar and red lead), blue (lapis lazuli), black (carbon-based) and false gold (golden tin). Tempera grassa was the painting technique identified. Two types of grounds were used: (i) gypsum in calligraphy decoration for the false gold technique, and (ii) synthetic minium in geometric drawings in carpentry. Organic insulating layers of linseed oil were used between paint strata. Artists applied synthetic minium to protect the wood (Juglans regia and conifer) against attack by xylophages. To lighten the surface darkened by this ground layer, powdered tin was added to achieve a metallic lustre. [source] Catalytic and Heating Behavior of Nanoscaled Perovskites under Microwave RadiationCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 7 2008T. Krech Abstract Perovskite powders of the types La0.5Ca0.5AlyM1,yO3,, (y = 0,0.8), M = Fe, Cr, Mn, Co and LaxSr1,xMnyCo1,y (x = 0.5,1, y = 0,1) were prepared via a sol-gel route according to the modified Pechini method. Incineration of the resins was performed before final sintering at 1000,°C for 6,h. The phase composition of the samples was established by X-ray powder diffraction analysis, and the lattice parameters were calculated using Rietveld analysis. The shape and size of the particles were determined via scanning electron microscopy and the specific surface area of the powder perovskites was established by the BET method. The principal particles were ca. 100,nm in size and formed agglomerates larger than 1.0,,m. The composition of the perovskites was established by EDX analysis. Following this, the catalytic behavior was tested by means of total oxidation of propane. The catalytic performance was measured at atmospheric pressure with 3,g of catalyst in a fixed-bed quartz reactor (i.d. = 18,mm) under thermal-assisted and microwave-assisted conditions. Initial results show a strong dependence of the catalytic and heating behavior on the nature of the M-atom and its number of unpaired d-electrons as well as on the particle size and its specific surface area. No significant difference in the results could be detected from comparison of the two heating methods. [source] | |||||||||||||