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EDX
Terms modified by EDX Selected AbstractsCrystal growth features and properties of layered rare earth and barium cobaltatesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4-5 2005G. L. Bychkov Abstract High quality single crystals of LnBaCo2O5+, (0 < , < 1) (Ln = Pr, Eu, Gd, Tb, Dy) with rectangular shape and average dimensions 5 mm × 5 mm × 1 mm were grown for the first time from overstoichiometric flux melt. The data on the primary crystallization field of most cobaltate phases, which appear in parts of corresponding Gibbs triangles in the range 1373 , 1523 K are discussed. Bulk single crystals of new phases HoBaCo4O7 up to 300 mm3, YBaCo4O7 and TbBaCo4O7 up to 10 mm3 in volume were grown first. A solution of these compounds structure has been found in the space group P63mc. For the Ln = Pr, Gd, Sm, Tb, Dy, Ho based systems under the liquidus line there are several other new cobaltate phases of both perovskite, and hexagonal crystal structure. Stability of the double perovskite phase and temperature of the antiferromagnetic , ferromagnetic phase transition in relation to the radius of rare earth ions are compared. The data on the exact analysis of chemical composition, including EDX and iodometric titration, as well as results on magnetic susceptibility of EuBaCo1- xAlxO5+, (0 < x < 0.3) are discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation and Characterization of a Tin Pentacyanonitrosylferrate-Modified Carbon Ceramic Electrode: Application to Electrocatalytic Oxidation and Amperometric Detection of L -CysteineELECTROANALYSIS, Issue 7 2009H. Razmi Abstract The sol-gel technique was used to construct tin pentacyanonitrosylferrate (SnPCNF) modified composite carbon ceramic electrode (CCE). This involves two steps: construction of CCE containing metallic Sn powder and then electrochemical creating of SnPCNF on the surface of CCE. The SnPCNF modified CCE (SnPCNFlCCE) was characterized by energy-dispersive X-ray (EDX), FTIR and cyclic voltammetry (CV) techniques. The SnPCNF film showed electrocatalytic activity toward the oxidation of L -cysteine. A linear calibration plot was obtained over the L -cysteine concentration range 1,51,,M using chronoamperometry. L -cysteine was determined amperometrically at the surface of this modified electrode. The detection limit (for a signal to noise of 3) and sensitivity were found to be 0.62,,M and 126,,A/mM, respectively. [source] Preparation, Electrochemistry, and Electrocatalytic Activity of Lead Pentacyanonitrosylferrate Film Immobilized on Carbon Ceramic ElectrodeELECTROANALYSIS, Issue 21 2008H. Razmi Abstract Lead pentacyanonitrosylferrate (PbPCNF), a new Prussian blue analog, was immobilized on the surface of a carbon ceramic electrode (CCE) prepared by sol-gel method. The immobilization process consists of adding a certain amount of metallic lead to the electrode matrix before gelation, and chemical derivatization of Pb on the electrode surface to a PbPCNF solid film by immersing the electrode in a solution of sodium pentacyanonitrosylferrate (PCNF). The composition of the synthesized PbPCNF was characterized by FTIR, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) techniques. The resulting modified electrode showed electroactivity at two redox centers. The electrochemical behavior of the PbPCNF modified carbon ceramic electrode (PbPCNF|CCE) was studied by cyclic voltammetry. Under optimized conditions the peak-to-peak separation is only 39,mV, indicative of a surface reaction. Ion effects of the supporting electrolyte suggest that cations have a considerable effect on the electrochemical behavior of the modified electrode. The transfer coefficient (,) and the charge transfer rate constant at the modifying film|electrode interface (ks) were calculated. The electrocatalytic activity of the modified electrode toward the electro-reduction of peroxodisulfate was studied in details. [source] Synthesis and Characterization of MWNTs/Au NPs/HS(CH2)6Fc Nanocomposite: Application to Electrochemical Determination of Ascorbic AcidELECTROANALYSIS, Issue 16 2008Jian-Ding Qiu Abstract In this article, a detailed electrochemical study of a novel 6-ferrocenylhexanethiol (HS(CH2)6Fc) self-assembled multiwalled carbon nanotubes-Au nanoparticles (MWNTs/Au NPs) composite film was demonstrated. MWNTs/Au NPs were prepared by one-step in situ synthesis using linear polyethyleneimine (PEI) as bifunctionalizing agent. HS(CH2)6Fc, which acted as the redox mediator, was self-assembled to MWNTs/Au NPs via Au-S bond. Transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transformed infrared absorption spectroscopy (FT-IR), UV-visible absorption spectroscopy, and cyclic voltammetry were used to characterize the properties of the MWNTs/Au NPs/HS(CH2)6Fc nanocomposite. The preparation of the nanocomposite was very simple and effectively prevented the leakage of the HS(CH2)6Fc mediator during measurements. The electrooxidation of AA could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of MWNTs/Au NPs. The nanocomposite modified electrode exhibited excellent catalytic efficiency, high sensitivity, good stability, fast response (within 3,s) and low detection limit toward the oxidation of AA at a lower potential. [source] Ultrasound-Assisted Synthesis of CuO Nanorods in a Neat Room-Temperature Ionic LiquidEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2009Tarek Alammar Abstract CuO nanorods were prepared via ultrasound-assisted synthesis in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] as a reaction medium. The structure and morphology of CuO nanorods were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), vibrational and UV/Vis absorption spectroscopy. The synthesized CuO nanocrystals are of rod like shape with lengths from 30 to 100 nm and diameters of about 10 nm. Quantum size effects were observed as the bandgap of the CuO nanorods was determined to 2.41 eV from UV/Vis absorption measurements, which is significantly larger than the bulk value. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Nb-Doped VO2 Thin Films Prepared by Aerosol-Assisted Chemical Vapour DepositionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2007Clara Piccirillo Abstract Niobium-doped vanadium dioxide (VxNb1,xO2, x = 0,0.037) thin films were prepared by aerosol-assisted chemical vapour deposition (AACVD) of vanadyl(IV) acetonate and niobium(V) ethoxide in ethanol. Samples were analysed by EDX, XRD, Raman, XPS and SEM. The analyses confirmed the deposition of niobium, even if no separated phase was formed; the morphological structure of the films was affected by the dopant presence. The thin films showed thermochromic behaviour, with a marked change in optical properties above and below the switching temperature. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Tailoring Materials Properties by Accumulative Roll Bonding,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Tina Hausöl Accumulative roll bonding (ARB) as a method of severe plastic deformation (SPD) is an interesting established process to produce ultrafine-grained (UFG) sheet materials with high potential for light weight constructions. The ARB process offers a high flexibility for tailored material design. Al2O3 particles, carbon fibers and titanium foils are used as reinforcement of aluminum sheets introduced during accumulative roll bonding. Furthermore multicomponent materials are produced by cladding of different aluminum alloys. These sandwich-like structures allow to combine desired properties of the materials involved. Post-ARB heat treatment offers another possibility for tailoring materials properties of graded structures as shown by formation of TiAl3 in Al/Ti laminates. The tailored materials are investigated by means of SEM, EDX, nanoindentation experiments and tensile testing. [source] Thermal Shock Performance of Fine Grained Al2O3 Ceramics With TiO2 and ZrO2 Additions for Refractory Applications,ADVANCED ENGINEERING MATERIALS, Issue 6 2010Christos G. Aneziris Abstract Due to zirconia and titania additions carbon-free fine grained alumina ceramics are produced with superior thermal shock performance. The decomposition of Al2TiO5 in the alumina doped matrix dominates during thermal shock attack and leads to higher strengths in comparison to the as sintered samples after thermal shock. EDX, EBSD, and XRD investigations describe the phase evolution before and after quenching the samples from 950 to 1200,°C in water, respectively. [source] Antheraea assama Silk Fibroin-Based Functional Scaffold with Enhanced Blood Compatibility for Tissue Engineering Applications,ADVANCED ENGINEERING MATERIALS, Issue 5 2010Naresh Kasoju Abstract The architecture and surface chemistry of a scaffold determine its utility in tissue engineering (TE). Conventional techniques have limitations in fabricating a scaffold with control over both architecture and surface chemistry. To ameliorate this, in this report, we demonstrate the fabrication of an Antheraea assama silk fibroin (AASF)-based functional scaffold. AASF is a non-mulberry variety having superior qualities to mulberry SF and is largely unexplored in the context of TE. First, a 3D scaffold with biomimetic architecture is fabricated. The scaffold is subsequently made blood compatible by modifying the surface chemistry through a simple sulfation reaction. EDX and FTIR analysis demonstrate the successful sulfation of the scaffold. SEM observations reveal that sulfation has no any effect on the scaffold architecture. TGA reveals that it has increased thermal stability. The sulfation reaction significantly improves the overall hydrophilicity of the scaffold, as is evident from the increase in water holding capacity; this possibly enhances the blood compatibility. The enhancement in blood compatibility of the sulfated scaffold is determined from in vitro haemolysis, protein adsorption and platelet adhesion studies. The sulfated scaffold is non-toxic and supports cell adhesion and growth, as revealed by indirect and direct contact-based in vitro cytotoxicity assays. This study reveals that the AASF-based functional scaffold, which has biomimetic architecture and blood-compatible surface chemistry, could be suitable for TE applications. [source] Modelling of Hot Ductility during Solidification of Steel Grades in Continuous Casting , Part II,ADVANCED ENGINEERING MATERIALS, Issue 3 2010Bernd Böttger In continuous casting, the probability of hot cracks developing strongly depends on the local solidification process and the microstructure formation. In ref. 1, an integrative model for hot cracking of the initial solid shell is developed. This paper focuses on solidification modelling, which plays an important role in the integrated approach. Solidification is simulated using a multiphase-field model, coupled online to thermodynamic and diffusion databases and using an integrated 1D temperature solver to describe the local temperature field. Less-complex microsegregation models are discussed for comparison. The results are compared to EDX results from strand samples of different steel grades. [source] Surface characteristics of dentin experimentally exposed to hydrofluoric acidEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2003Thomas Pioch The purpose of this study was to test the effect of hydrofluoric acid (HF) on the surface characteristics of dentin in vitro. Dentin was exposed in 50 human molars and divided into five groups according to different etching schedules: (i) no etching, (ii) 15 s HF, (iii) 15 s H3PO4, (iv) 15 s HF and 15 s H3PO4, (v) 15 s H3PO4 and 15 s HF. Teeth were examined under a scanning electron microscope equipped with energy-dispersive X-ray (EDX) or two layers of fluorescence-labeled primer followed by the composite were applied, and the teeth were sectioned and examined using confocal laser scanning microscopy (CLSM). With scanning electron microscopy, no openings of dentinal tubules were found in groups (i), (ii), and (iv). In group (v) only a few tubules were opened and in group (iii) the smear layer was completely removed and tubules appeared open. The EDX analysis revealed that fluoride was incorporated into the dentin surface when HF was used. With CLSM, distinct hybrid layers could be detected only in group (iii). In group (v) the hybrid layer appeared less established compared with group (iii). No dentin hybridization was found in groups (i), (ii), and (iv). It is concluded that HF has the ability to close the openings of dentin tubules which were opened due to etching by phosphoric acid and cannot dissolve the smear layer. [source] General Corrosion and Galvanic Corrosion Properties of Differently PVD Treated Magnesium Die Cast Alloy AZ91,ADVANCED ENGINEERING MATERIALS, Issue 12 2003H. Hoche Developing PVD coating systems with better corrosion resistance leads to a duplex process, consisting of a plasma anodisation and an Al2O3 top coating which can both be performed in a modified commercial PVD unit. The tested specimens were investigated by means of optical microscopy, SEM and EDX. Furthermore a novel immersion technique to determine the time dependent corrosion behavior of coated magnesium alloys is introduced. [source] Titanium Containing ,-MnO2 (TM) Hollow Spheres: One-Step Synthesis and Catalytic Activities in Li/Air Batteries and Oxidative Chemical ReactionsADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Lei Jin Abstract Titanium containing ,-MnO2 octahedral molecular sieves having hollow sphere structures are successfully prepared for the first time using a one-step synthesis method. Titanium cations are used as structure-directing agents in the synthesis process. The assembly of the hollow spheres is carried out at the beginning of the process. Various techniques including XRD, N2 adsorption, SEM, EDX, RAMAN, TEM, XPS, and TGA are employed for the materials characterization. Ti is incorporated into the MnO2 framework in isolated sites, and TiO2 phases (anatase and rutile) are not observed. When introduced in medium-sized lithium-air batteries, the materials give very high specific capacity (up to 2.3 A h g,1). These materials are also catalytically tested in the oxidation of toluene with molecular oxygen at atmospheric pressure, showing significant oxidative catalytic activities in this difficult chemical reaction. [source] Catalyst-Free Synthesis and Characterization of Metastable Boron Carbide NanowiresADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Aruna Velamakanni Abstract Catalyst-free growth of boron carbide nanowires is achieved by pyrolysis of diborane and methane at 650,750,°C and around 500 mTorr in a quartz tube furnace. Electron-diffraction analysis using a novel diffraction-scanning transmission electron microscopy (D-STEM) technique indicates that the crystalline nanowires are single-crystal orthorhombic boron carbide. TEM images show that the nanowires are covered by a 1,3,nm thick amorphous layer of carbon. Elemental analysis by electron energy loss spectroscopy (EELS) shows only boron and carbon while energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) show the presence of oxygen as well as boron and carbon. [source] The Role of Sulfur in the Synthesis of Novel Carbon Morphologies: From Covalent Y-Junctions to Sea-Urchin-Like StructuresADVANCED FUNCTIONAL MATERIALS, Issue 8 2009Jose´ M. Romo-Herrera Abstract A detailed characterization, using high resolution electron microscopy/microanalysis (SEM, TEM, HRTEM, and EDX), reveals tubular carbon nanostructures exhibiting complex and fascinating morphologies. The materials were obtained by sulfur-assisted chemical vapor deposition. It is demonstrated that S not only acts on the catalyst, but also can be detected in the carbon lattice of the nanostructures. The experimental data presented here confirms the critical role of S, which is responsible for inducing curvature and therefore influencing the final carbon nanostructure morphology. In particular, different types of covalent Y-junctions of CNTs and even sea urchin-like nanostructures were produced and their experimental conditions are listed and discussed. [source] Highly Stable Nickel Hexacyanoferrate Nanotubes for Electrically Switched Ion Exchange,ADVANCED FUNCTIONAL MATERIALS, Issue 15 2007W. Chen Abstract Nickel hexacyanoferrate (NiHCF) nanotubes are fabricated by an electrokinetic method based on the distinct surface properties of porous anodic alumina. By this method, nanotubes can be formed rapidly with the morphologies faithfully replicating the nanopores in the template. The prepared nanotubes were carefully characterized using SEM and TEM. Results from IR, UV, EDX, and electrochemical measurements show that the NiHCF nanotubes exist only in the form of K2Ni[Fe(CN)6]. Because of this single composition and unique nanostructure, NiHCF nanotubes show excellently stable cesium-selective ion-exchange ability. The capacity for electrodes modified with NiHCF nanotubes after 500,potential cycles retains 95.3,% of its initial value. Even after 1500 and 3000 cycles, the NiHCF nanotubes still retain 92.2,% and 82.9,%, respectively, of their ion-exchange capacity. [source] Concentric Sub-micrometer-Sized Cables Composed of Ni Nanowires and Sub-micrometer-Sized Fullerene Tubes,ADVANCED FUNCTIONAL MATERIALS, Issue 7 2007F. Tao Abstract Highly ordered arrays of submicrometer-sized coaxial cables composed of submicrometer-sized C60 and C70 tubes filled with Ni nanowires are successfully prepared by combining a sol,gel method with an electrodeposition process. The wall thickness of the submicrometer-sized tubes can be adjusted by the concentration of fullerenes and the immersion time. The thermal stability of the submicrometer-sized C60 tubes is studied by Raman spectroscopy and it is found that these structures can be easily decomposed to form carbon nanotubes at relatively low temperatures (above 573,K) in an alumina template. These novel coaxial cable structures have been characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), scanning electron microscopy (SEM), field-emission SEM (FESEM), Raman spectroscopy, elemental mapping, energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), vibrating sample magnetometer (VSM) experiments, and superconducting quantum interference device (SQUID) measurements. Magnetic measurements show that these submicrometer-sized cables exhibit enhanced ferromagnetic behavior as compared to bulk nickel. Moreover, submicrometer-sized C70/Ni cables show uniaxial magnetic anisotropy with the easy magnetic axis being parallel to the long axis of the Ni nanowires. C70/Ni cables also exhibit a new magnetic transition at ca.,10,K in the magnetization,temperature (M,T) curve, which is not observed for the analogous C60/Ni structures. The origin of this transition is not yet clear, but might be related to interactions between the Ni nanowires and C70 molecules. There is no preferred magnetization axis in submicrometer-sized C60/Ni cables, which implies that the Ni nanocrystals have different packing modes in the two composites. These different crystalline packing modes lead to different magnetic anisotropy in the two composites, although the Ni nanocrystals have the same face-centered cubic (fcc) structure in both cases. [source] Influence of Structural Principles on the Mechanics of a Biological Fiber-Based Composite Material with Hierarchical Organization: The Exoskeleton of the Lobster Homarus americanusADVANCED MATERIALS, Issue 4 2009Helge-Otto Fabritius Abstract The cuticle of the lobster Homarus americanus is a nanocomposite, such as most structural biological materials. It consists of a matrix of chitin-protein fibers associated with various amounts of crystalline and amorphous calcium carbonate in the rigid parts of the body, and is organized hierarchically at all length scales. One prominent design principle found in the hierarchical structure of such biological fibrous composite materials is the twisted plywood structure. In the lobster cuticle, it is formed by superimposing and gradually rotating planes of parallel aligned chitin-protein fibers. To adjust the mechanical properties to the requirements on the macroscopic level, the spatial arrangement and the grade of mineralization of the fibers can be modified. A second design principle of lobster cuticle is its honeycomb-like structure, generated by the well-developed pore canal system, whose twisted ribbon-shaped canals penetrate the cuticle perpendicular to its surface. Due to the hierarchical structure, the mechanical properties of the lobster cuticle have to be investigated at different length scales, which is essential for the understanding of the structure,mechanical function relations of mineralized tissues (e.g., potentially also bone and teeth). In order to investigate the influence of the structural principles on the mechanical properties on the macroscopic scale miniaturized tensile, compression, and shear tests were carried out to obtain integral mechanical data. Characterization of the microstructure included scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDX) measurements. [source] An Environmentally Benign, Highly Efficient Catalytic Reduction of p -Nitrophenol using a Nano-Sized Nickel Catalyst Supported on Silica-AluminaADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Islam Hamdy Abd El Maksod Abstract A green and effective method is reported for the reduction of p -nitrophenol to p -aminophenol using a nano-sized nickel catalyst supported on silica-alumina in the presence of hydrazine hydrate as an alternative source of hydrogen. It was found that nickel loaded on a silica-alumina support is a very effective catalyst in the hydrogenation of p -nitrophenol to p -aminophenol. Thus it attained 100% conversion in only 69 seconds instead of 260 seconds for commercial Raney nickel. In addition, the possibility to reuse it more than one time with great efficiency gives it another advantage over commercial Rainey nickel which cannot be used more than once. This economical and environmentally friendly method provides a potentially new approach for the synthesis of the intermediate product of paracetamol in industry, which overcomes the drawbacks of the known reduction methods. The prepared catalysts were fully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and electron spin resonance (ESR) tehniques. [source] Defective enamel ultrastructure in diabetic rodentsINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2004M. ATAR Summary. We investigated six different types of diabetic rodents. Four expressed a genetic obesity resulting in diabetes. One developed diabetes induced by a diet-dependent obesity, and one with genetic diabetes received anti-diabetic medication. The tooth samples were examined under a scanning electron microscope and with an energy dispersive microanalysis (EDX). The electron micrographs showed severe, varying degrees of damage within the six different diabetic animal types, such as irregular crystallite deposition and prism perforations in genetically obese animals compared to less-disordered prism structures in diet-dependent obesity. Anti-diabetic medication resulted in normal enamel ultrastructure. The EDX analysis revealed a reduction in the amount of calcium and phosphorus in all regions affected by diabetes. Based on these animal studies, we suggest that both juvenile diabetes type I (in infants) and adult diabetes type II (in pregnant mothers, affecting the developing foetus) may affect the normal development of teeth in humans. [source] Estimation of cobalt coating layer thickness on acicular Fe3O4 powder using HR-TEMJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2001Keitarou Sakai The thicknesses of cobalt coating layers grown on four different types of acicular Fe3O4 particles were estimated from the analysis of lattice images and from the determination of the Co depth profile using high-resolution transmission electron microscopy (HR-TEM) coupled with an energy dispersive X-ray (EDX) analysis system. It was observed that the coating thickness might vary with the crystallite size resulting from the growth mechanism of the coating layer. In this study, two different layer thicknesses, 40,Å and less than 10,Å, were evidenced for crystallite sizes of 390,Å and 350,Å, respectively. [source] Application of hydrophilic finished of synthetic fabrics coated with CMC/acrylic acid cured by electron beam irradiation in the removal of metal cations from aqueous solutionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Sayeda M. Ibrahim Abstract Modified textile fabrics were used to remove Cu+2 and Cr+3 ions from aqueous solutions. For this purpose, modified Nylon-6, polyester woven and knitted fabrics were prepared by coating the surface with a thin layer of aqueous solution of carboxymethyl cellulose (CMC) and acrylic acid (AAc) of thickness 25 ,m. Radiation crosslinking of the coated layer was carried out by electron beam irradiation with a constant dose of 30 kGy. Morphology of the coated fabrics was examined by scanning electron microscope (SEM) which indicated the compatibility between the coated layer and fabrics. Properties attributed to the hydrophilicity, especially water uptake and weight loss before and after several washing cycles were followed up. The effect of AAc concentration on the hydrophilic properties of the coated fabrics was studied. A considerable enhancement in water uptake has been attained on increasing AAc content in solution in case of nylon-6 followed by polyester woven followed by polyester knitted fabrics. The performances of the modified textile fabrics were evaluated for the recovery of Cu+2 and Cr+3 from aqueous solution. The metal ion absorption efficiency of the modified textile fabrics was measured using UV Spectrophotometer analysis and EDX. Parameters affecting the efficiency of these textile fabrics in the removal of metal ions from aqueous solution namely, concentration of AAc and the immersion time were studied. It was found that there was a marked increase in the recovery of metal ions on increasing both immersion time and concentration of AAc. This study evidences that the modified textile fabrics can be used for the purpose of removal of some heavy metals such as Cu and Cr. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] A study of the mechanisms of divalent copper binding to a modified cellulose adsorbentJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010David William O'Connell Abstract A modified cellulose material was prepared by grafting glycidyl methacrylate to cellulose (Cell- g -GMA) with subsequent functionalization with imidazole (Cell- g -GMA-imidazole). This latter compound was used in the adsorption of copper from aqueous solution. The mechanism of Cu(II) binding onto the cell- g -GMA-imidazole was investigated at the molecular level using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), x-ray photoelectron spectroscopy (XPS), energy dispersive x-ray analysis (EDX) and X-ray diffraction (XRD). FTIR and Raman spectroscopy provided an insight into the extent to which perturbation of the imidazole ring occurred following adsorption of the metal while XPS spectra indicated the binding of Cu(II) ions to nitrogen atoms by the appearance of additional binding energy peaks for nitrogen on the cellulose- g -GMA-imidazole sample post adsorption. The EDX technique provided clear evidence of the physical presence of both the copper and sulfate on the cellulose- g -GMA-imidazole material post adsorption. XRD analysis further confirmed the presence of a copper species in the adsorbent material as copper sulfate hydroxide (Cu3(OH)4SO4 - antlerite). The XRD studies further suggest that the overall extent of Cu(II) adsorption is not alone a combination of true metal chelation as suggested by FTIR, Raman and XPS, but also a function of surface precipitation of the polynuclear copper species. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Calcium-phosphate surface coating by casting to improve bioactivity of titaniumJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 5 2001Taiji Sohmura Abstract In order to improve the bioactivity of titanium, an original surface treatment was attempted with the use of a casting technique was attempted. Pure titanium was cast into a special graphite mold in which the cavity wall was coated with hydroxyapatite (HA) powder. According to analyses of X-ray diffraction and EDX, the existence of HA and CaO and uptake of Ca and P on the surface of the titanium castings were identified. By immersing the specimen in Hank's solution, the concentrations of Ca and P on the surface increased with immersion time, and the formation of a thin layer with characteristics of spherical HA precipitates was observed after 1 week. The concentrations of Ca and P elements and the Ca/P ratio on the HA layer increased with immersion time. The formation of the HA layer on the titanium cast by this treatment was significantly accelerated compared with pure titanium. The present surface treatment of Ti is expected to improve early bone fixation of Ti implants. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 478,485, 2001 [source] Sulphur, thiols, and disulphides in the fish epidermis, with remarks on keratinizationJOURNAL OF FISH BIOLOGY, Issue 4 2007W. Meyer Energy dispersive x-ray (EDX) analysis and qualitative and quantitative histochemistry were applied to study the distribution and contents of sulphur, thiols and disulphides in the epidermis of the river lamprey Lampetra fluviatilis, the lesser spotted dogfish Scyliorhinus canicula and the brown trout Salmo trutta fario. Thiols generally reacted weakly throughout the entire epidermis, whereas disulphide reactions were more distinct and differentiated. In the river lamprey, the concentrations of -S-S- groups clearly increased in the developing mucous cells from the stratum basale to the stratum superficiale; skein cells and granular cells reacted negatively to weakly. In the lesser spotted dogfish, amounts of disulphides appeared at moderate concentrations, and only goblet cells displayed a strong reaction. In the brown trout, filament cells showed low concentrations or weak reactions of disulphides, goblet cells and the most outer superficial cells stained strongly. Sulphur distribution and contents generally supported the histochemical observations in normal epidermis cells (absolute sulphur contents: 41,59 mM), only the brown trout showed high amounts of sulphur in the stratum basale (81 mM). The findings corroborate the view that there is an inverse correlation between keratinization and mucous secretion in normal fish epidermis. The sometimes distinct contents of disulphides in the outer mucous layer indicate that this system could endure higher mechanical stress than predictable from its large amounts of neutral glycoproteins. [source] Facile synthesis of polyaniline hemispheres in diethyl ether/ice mixture solvent and growth mechanism studyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2010Hui-yan Ma Abstract By using the new methodology of synthesis of container structure, we demonstrate the ability to control an improved ice-templating method to synthesis of polyaniline (PANI) in the form of hemisphere. The influence of the synthetic parameters, such as the concentration of doping-acid, oxidant, and aniline on the morphologies of PANI structures, has been investigated. It is determined that the doping acid and the second solvent added (such as diethyl ether absolute) have great positive influence on the formation of product's micro-morphology. The structure and morphology of PANI hemispheres are characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) patterns, energy-dispersive X-ray analysis (EDX), optical microscope images, and scanning electron microscope images (SEM). The formation mechanism of hemispheres in this article is well suggested. PANI hemispheres have super performance in sensitivity, time response to NH3 compared with traditional polymerization at room temperature. This work extends the field of functional materials with complex container structure and offers a new green route to synthesis of hemispherical container structure. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3596,3603, 2010 [source] Novel synthesis of polyethylene,poly(dimethylsiloxane) copolymers with a metallocene catalystJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2004Andrés E. Ciolino Abstract Polyethylene,poly(dimethylsiloxane) copolymers were synthesized in solution from an ethylene monomer and an ,-vinyl poly(dimethylsiloxane) (PDMS) macromonomer at 363 and 383 K with EtInd2ZrCl2/methylaluminoxane as a catalyst. The copolymers obtained were characterized with Fourier transform infrared spectroscopy, 1H and 13C NMR, size exclusion chromatography, and differential scanning calorimetry. The rheological properties of the molten polymers were determined under dynamic shear flow tests at small-amplitude oscillations, whereas the physical arrangement of the phase domains was analyzed with scanning electron microscopy (SEM)/energy dispersive X-ray (EDX). The analysis of the catalyst activity and the resulting polymers supported the idea of PDMS blocks or chains grafted to polyethylene. The changes in the rheological behavior and the changes in the Fourier transform infrared and NMR spectra were in agreement with this proposal. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2462,2473, 2004 [source] Mechanical Behavior and Failure Analysis of Prosthetic Retaining Screws after Long-Term Use In Vivo.JOURNAL OF PROSTHODONTICS, Issue 3 2008Microhardness Analysis, Part 2: Metallurgical Abstract Purpose: This study involved testing and analyzing multiple retrieved prosthetic retaining screws after long-term use in vivo to: (1) detect manufacturing defects that could affect in-service behavior; (2) characterize the microstructure and alloy composition; and (3) further characterize the wear mechanism of the screw threads. Materials and Methods: Two new (control) screws from Nobel Biocare (NB) and 18 used (in service 18,120 months) retaining screws [12 from NB and 6 from Sterngold (SG)] were: (1) metallographically examined by light microscopy and scanning electron microscopy (SEM) to determine the microstructure; (2) analyzed by energy dispersive X-ray (EDX) microanalysis to determine the qualitative and semiquantitative average alloy and individual phase compositions; and (3) tested for Vickers microhardness. Results: Examination of polished longitudinal sections of the screws using light microscopy revealed a significant defect in only one Group 4 screw. No significant defects in any other screws were observed. The defect was considered a "seam" originating as a "hot tear" during original casting solidification of the alloy. Additionally, the examination of longitudinal sections of the screws revealed a uniform homogeneous microstructure in some groups, while in other groups the sections exhibited rows of second phase particles. The screws for some groups demonstrated severe deformation of the lower threads and the bottom part of the screw leading to the formation of crevices and grooves. Some NB screws were comprised of Au-based alloy with Pt, Cu, and Ag as alloy elements, while others (Groups 4 and 19) were Pd-based with Ga, Cu, and Au alloy elements. The microstructure was homogeneous with fine or equiaxed grains for all groups except Group 4, which appeared inhomogeneous with anomalous grains. SG screws demonstrated a typical dendritic structure and were Au-based alloy with Cu and Ag alloy elements. There were differences in the microhardness of gold alloy screws from NB and SG as well as palladium alloy screws from NB. Conclusions: Significant differences within NB retaining screws and between NB and SG screws were found for microstructure, major alloy constituents, and microhardness. [source] Functional mapping of carious enamel in human teeth with Raman microspectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 5 2008H. Kinoshita Abstract We employed Raman microspectroscopy to measure the Raman spectra of phosphate in sound and carious tooth substance. The peak intensity at 960 cm,1 of the phosphate (PO43,) symmetric stretching vibrational mode (,1) in sound enamel was stronger than that of sound dentin, which indicated that sound enamel contained more phosphate than sound dentin. Furthermore, the element analysis of phosphate in sound teeth substance, measured using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscope (EDX), gave similar results to those of the Raman measurement. In addition, the border between sound enamel and dentin was clearly demonstrated by mapping the image of the Raman spectrum of phosphate. The mapping image of phosphate in the carious enamel region revealed a heterogeneous low Raman spectrum intensity of phosphate in the area surrounding carious enamel; this finding indicates that phosphate had dissolved from the tooth substance in such areas. In contrast with the decrease in the Raman spectrum intensity of phosphate, the intensity of amide I increased mainly in the low-phosphate area. Although it remains very difficult to clinically identify the accurate border between sound and carious tooth substance, this distinction may be enabled by using the Raman spectrum of carious tooth substance. Copyright © 2008 John Wiley & Sons, Ltd. [source] The Chemical Interaction of Silver,Palladium Alloy Electrodes with Bismuth-Based PiezomaterialsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2010Denis Schuetz Multilayer technology relies heavily on the chemical compatibility of metal and ceramic. This work focuses on the ceramic,electrode interaction between 92Bi0.5Na0.5TiO3,6 BaTiO3,2K0.5Na0.5NbO3 [(Bi0.46Na0.47Ba0.06K0.01)(Nb0.02Ti0.98)O3], a promising actuator material and forerunner to an emerging class of lead-free actuator materials, and a silver,palladium alloy for inner electrodes, the only currently viable material for the firing temperatures necessary (1100°C). Of special concern was the high content of bismuth in the ceramic since prior investigations suggest that Bi2O3 (as well as various bismuth titanates) used as a fluxor in electroceramics are prone to forming the intermediate-phase bismuth palladate (Bi2PdO4), which can lead to poor contacting and delamination of multilayer stacks. Remarkably, no evidence of bismuth palladate formation could be found. However, the phase relations of the bulk ceramic have proven to be quite complex. Potassium was being drained out of the bulk ceramic either constituting the secondary phase K4Na2(TiO3)3 in unmodified experiments or evaporating and being replaced by silver in samples in contact with Ag. Mechanisms for the formation of these phases or the lack thereof are proposed. These findings were obtained by XRD, TG-DSC, and SEM with EDX, and LA-ICPMS. [source] | |||||||||||||||||||||||||||||||