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Electron Microscopy (electron + microscopy)
Kinds of Electron Microscopy Terms modified by Electron Microscopy Selected AbstractsREMOVAL OF LIPID FROM SURFACES OF ROASTED PEANUTS BY SONICATION AS ASSESSED BY FLUORESCENCE AND SCANNING ELECTRON MICROSCOPYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2010PETER WAMBURA ABSTRACT Peanut oil migrates to the outer surface during roasting, where it comes into contact with oxygen, leading to the oxidation reactions. Because of its cleaning effect, power ultrasound (sonication) was used for removing surface lipid of roasted peanuts. Georgia green runner-type peanuts were roasted at 178C for 15 min. Roasted peanuts were subjected to lipid extraction in n-hexane by sonication. Fluorescent and electron scanning micrographs revealed that the surface of sonicated peanuts was free of oil stains, as opposed to that of freshly roasted peanuts. These results showed that power ultrasound could remove the lipids from peanut surfaces very effectively. Details of microstructure of sonicated peanuts as was observed using scanning electron microscope reveal that 10 min sonication was sufficient to extract most of the lipids on the roasted peanut surfaces. Fluorescence and scanning electron microscopy are useful in peanut analysis because they can detect lipids in low concentration. PRACTICAL APPLICATIONS There is increasing interest of quick procedures to examine the surfaces of roasted peanut samples after undergoing treatments, such as removal of lipids. This research demonstrated the significant use of fluorescent and scanning electron microscopes to quickly study the extent of lipid removal from the surface of roasted peanuts after power ultrasound treatment (sonication). [source] Optimization of Cr8O21 targets for Pulsed Laser DepositionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2005L. Tortet Abstract This work describes the preparation of Cr8O21 pellets with optimised mass density to be used as targets for Pulsed Laser Deposition (PLD) of chromium dioxide thin films. Cr8O21 is synthesised by thermal decomposition of CrO3, at 270 °C. An attempt to reduce the grain size of the Cr8O21 powder to the nanometer scale has been made in order to increase the density of the pressed and sintered pellets serving as targets. The morphology of those starting fine powders as well as of targets (before and after laser ablation) and the corresponding thin films were characterized and studied using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Raman spectroscopy. The composition of the films is a mixture of crystallised Cr2O3 and amorphous CrO2. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The effect of alloying elements on the crystallization behaviour and on the properties of galvanized coatingsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2004G. Vourlias Abstract The influence of the alloying elements on the interface reactions of zinc coatings during the galvanization process was examined. These reactions affect the crystallization and the structure and properties of the outer layer of the coatings. Depending on the type and concentration of the alloying additions in the galvanizing bath differences were induced in the crystallization process of the Fe-Zn phases. It was found that both the concentration and the distribution of the alloying elements played an important role in the growth of the phases. The formation of the phases and the distribution of the alloying elements in the coatings were determined using X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM) associated with an Energy Dispersive X-Ray Spectroscopy (EDS) analysis. Finally the behaviour of the galvanized coatings was examined under accelerated salt spray corrosion conditions. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ultrastructural and electron energy-loss spectroscopic analysis of an extracellular filamentous matrix of an environmental bacterial isolateENVIRONMENTAL MICROBIOLOGY, Issue 9 2007Uta Böckelmann Summary Strain F8, a bacterial isolate from ,river snow', was found to produce extracellular fibres in the form of a filamentous network. These extracellular filaments, which were previously shown to be composed of DNA, have been studied for the first time by ultrastructural and electron energy-loss spectroscopy in the present work. ,Whole mount' preparations of strain F8 indicate these polymers are ultrastructurally homogeneous and form a network of elemental filaments, which have a width of 1.8,2.0 nm. When incubated at pH 3.5 with colloidal cationic ThO2 tracers they become intensely stained (electron dense), affording direct evidence that the fibres are negatively charged and thus acidic chemically. Elemental analysis of the extracellular filaments by Energy-filtered Transmission Electron Microscopy revealed phosphorus to be the main element present and, because pretreatment of F8 cells with DNase prevented thorium labelling, the fibres must be composed of extracellular DNA (eDNA). Neither ultrathin sections nor ,whole mount negative stain' caused DNA release by general cell lysis. Additionally, cells infected with phages were never observed in ultrathin sections and phage particles were never detected in whole mount samples, which rules out the possibility of phages being directly involved in eDNA release. [source] Study of the Defects in Sintered SnO2 by High-Resolution Transmission Electron Microscopy and CathodoluminescenceEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2007David Maestre Abstract The defect structure of sintered SnO2 was investigated by high-resolution transmission electron microscopy (HRTEM), cathodoluminescence (CL), and electrical measurements. HRTEM shows the presence of the SnO phase in the sintered samples as well as twinning, stacking faults, and disordered intergrowths. The sintered samples annealed under an oxygen atmosphere show changes in the defect structure and in the CL spectra. In particular, the intensity of a CL band at 1.94 eV, related to oxygen vacancies, decreased as the electrical resistivity increased. The results are discussed by considering the presence of stoichiometric defects such as oxygen vacancies and Sn interstitials in the final structure and their evolution during the annealing process under an oxygen atmosphere. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Nano-characterization of Cast Structures by FIB-Tomography,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2008F. Lasagni In this communication, the three dimensional architectures of different Al-Si-(Mg) alloys are analyzed using SEM (Scanning Electron Microscopy)/FIB (Focus Ion Beam), EDS (Energy Dispersive Spectroscopy)/FIB and SEM-EDS/FIB tomographic methods. Several aspects for the imaging and quantification of the results are discussed describing the advantages and limitations of the methods to resolve submicron structures. [source] Transmission Electron Microscopy and Nano-Precipitation,ADVANCED ENGINEERING MATERIALS, Issue 12 2006T. Epicier Abstract We have presented here a rapid survey of some of the stringent results obtained by TEM and associated techniques in the precipitation studies conducted during the CPR ,Précipitation'. It clearly appears that TEM plays an irreplaceable role in the link between the understanding of the structure and chemistry of small precipitates and the modelling of the precipitation kinetics. [source] Preparation and Characterization of Styrene Butadiene Rubber Based Nanocomposites and Study of their Mechanical PropertiesADVANCED ENGINEERING MATERIALS, Issue 9 2004S. Sadhu Nanocomposites were prepared from styrene butadiene rubber (SBR) having different styrene contents and octadecyl amine modified Na-montmorillonite clay (OC). The modified and the unmodified clays were characterized with the help of X-ray diffraction technique (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). All these nanocomposites were then subjected to tensile testing. The modified clay-rubber nanocomposites showed improved tensile strength (55% increase) and elongation at break (76% increase) compared to those of the gum vulcanizates. [source] Transmission Electron Microscopy and UV,vis,IR Spectroscopy Analysis of the Diameter Sorting of Carbon Nanotubes by Gradient Density UltracentrifugationADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Romain Fleurier Abstract Diameter separation of single-walled carbon nanotubes is achieved via the density gradient ultracentrifugation process. Statistical analysis of the separated samples is performed using high-resolution transmission electron microscopy (HRTEM). The evolution of the diameter distribution with respect to the gradient density is extracted by analyzing hundreds of HRTEM images, and the results are found to be consistent with those estimated by UV,vis,IR spectroscopy. The efficiency of the separation process can be quantitatively characterized by the standard deviation of the diameter distribution, which is determined from the TEM analyses. This particular study indicated that for electric arc nanotubes dispersed in sodium cholate, diameter sorting is more efficient in the upper part of the gradient. [source] Determination of Size, Morphology, and Nitrogen Impurity Location in Treated Detonation Nanodiamond by Transmission Electron MicroscopyADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Stuart Turner Abstract Size, morphology, and nitrogen impurity location, all of which are all thought to be related to the luminescent properties of detonation nanodiamonds, are determined in several detonation nanodiamond samples using a combination of transmission electron microscopy techniques. Results obtained from annealed and cleaned detonation nanodiamond samples are compared to results from conventionally purified detonation nanodiamond. Detailed electron energy loss spectroscopy combined with model-based quantification provides direct evidence for the sp3 like embedding of nitrogen impurities into the diamond cores of all the studied nanodiamond samples. Simultaneously, the structure and morphology of the cleaned detonation nanodiamond particles are studied using high resolution transmission electron microscopy. The results show that the size and morphology of detonation nanodiamonds can be modified by temperature treatment and that by applying a special cleaning procedure after temperature treatment, nanodiamond particles with clean facets almost free from sp2 carbon can be prepared. These clean facets are clear evidence that nanodiamond cores are not necessarily in coexistence with a graphitic shell of non-diamond carbon. [source] High-pressure Freezing in CLEMIMAGING & MICROSCOPY (ELECTRONIC), Issue 1 2007A Correlative Light Electron Microscopy Study Research methods using so-called Correlative Light Electron Microscopy (CLEM) techniques have gained increasing attention in recent years. Most techniques have focused on the light microscopy part of the process. The processing for electron microscopy, however, deserves attention as well to get the most out of the technique. Some new developments, including the use of a superior fixation technique, are described. [source] Cell division in magnetotactic bacteria splits magnetosome chain in halfJOURNAL OF BASIC MICROBIOLOGY, Issue 4 2010Sarah S. Staniland Abstract Cell division in magnetotactic bacteria has attracted much interest, speculation and hypothesis with respect to the biomineralised chains of magnetic iron-oxide particles known as magnetosomes. Here we report direct Transmission Electron Microscopy (TEM) evidence that division occurs at a central point of the cell and the chain, cleaving the magnetosome chain in two. Additionally, the new magnetosome chain relocates rapidly to the centre of the daughter cell and the number of magnetosomes is directly proportional to the cell length, even during the division part of the cell cycle. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Glass analysis for forensic purposes,a comparison of classification methodsJOURNAL OF CHEMOMETRICS, Issue 5-6 2007Grzegorz Zadora Abstract One of the purposes of the chemical analysis of glass fragments (pieces of glass of linear dimension ca. 0.5,mm) for forensic purposes is a classification of those fragments into use categories, for example windows, car headlights and containers. The object of this research was to check the efficiency of Naïve Bayes Classifiers (NBCs) and Support Vector Machines (SVMs) to the application of the classification of glass objects when those objects may be described by the major and minor elemental concentrations obtained by Scanning Electron Microscopy coupled with an Energy Dispersive X-ray spectrometer which is routinely used in many forensic institutes. Copyright © 2007 John Wiley & Sons, Ltd. [source] Deagglomeration of nanoparticle aggregates via rapid expansion of supercritical or high-pressure suspensionsAICHE JOURNAL, Issue 11 2009Daniel To Abstract Deagglomeration of suspensions of alumina and titania nanopowders (i.e., nanoparticle aggregates) via rapid expansion of supercritical suspensions (RESS) or high-pressure suspensions (REHPS) was studied. The size distribution of fragmented nanopowders was characterized by online Scanning Mobility Particle Spectrometer (SMPS) and Aerodynamic Particle Sizer (APS), and by offline Scanning Electron Microscopy (SEM). SMPS and SEM measurements indicate that the average agglomerate sizes were well below 1 ,m, consistent with the length scales observed in our complementary RESS/REHPS mixing experiments using alumina and silica nanopowders. The APS measurements, on the other hand, were affected by reagglomeration during sampling and yielded an agglomerate size range of 1 to 3 ,m. Analysis of the RESS/REHPS process through compressible flow models revealed that both the shear stress in the nozzle and the subsequent impact of the agglomerates with the Mach disc in the free expansion region can lead to micron or sub-micron level deagglomeration. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] BIOREMEDIATIVE POTENTIAL OF CHROMULINA FREIBURGENSIS IN CULTURE FROM THE BERKELEY PITJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Dakel, S. M.1 & Mitman, G. G.2 1Department of Environmental Engineering; 2Department of Biological Sciences, Montana Tech of The University of Montana, Butte, MT 59701 USA The Berkeley Pit, part of the largest Superfund site in the United States, is an open-pit copper mine that operated from 1955 through 1982. Today, the Berkeley Pit contains approximately 1200 billion liters of metal laden water with an average pH of 2.7, and 12 grams/liter of dissolved solids. The principle dissolved ions include aluminum, arsenic, calcium, cadmium, copper, iron, potassium, magnesium, manganese, sulfates, and zinc. A species from Division Chrysophyta,Chromulina freiburgensis Dofl. was isolated from this extreme environment. This species has been tested in the laboratory through a series of controlled experiments to determine bioremediative potential. Optimal temperature was determined by monitoring growth with cell counts at temperatures ranging from 5°C to 40°C . The optimal nutrient ratio was determined by varying nitrogen (NaNO3) and phosphorus (Na2HPO4) levels. An experimental matrix varying nutrients was developed to test for bioremediative potential which included: initial and final pH measurements; initial and final Ion Chromatography Pairing,Atomic Emission Spectrometry (ICP-AES) for dissolved metals; and examination of final samples under Transmission Electron Microscopy (TEM). From these experiments, Chromulina freiburgensis was found to grow optimally in Berkeley Pit surface water with cell densities reaching ten million cells per milliliter at 10°C with additions of 50 mg NaNO3/L and 5 mg Na2HPO4/L. This large biomass was also found to increase diversity and abundance of heterotrophs. At the optimal nutrient level, this species was found to increase pH from 2.21 to 2.47 over 90 days. Significant removal of calcium, iron, nickel, and silica was observed. [source] Light and Electron Microscopy of the Compatible Interaction Between Arabidopsis and the Downy Mildew Pathogen Peronospora parasiticaJOURNAL OF PHYTOPATHOLOGY, Issue 6 2003E. M. Soylu Abstract In this study, we focused on compatible interactions between Peronospora parasitica isolate Emoy-2 and wild-type (Oy-0) and mutant (Ws- eds1) Arabidopsis thaliana accessions by using light and transmission electron microscopy (TEM). Light microscopy of compatible interactions revealed that conidia germinated and penetrated through the anticlinal cell walls of two epidermal cells. Rapid spreading of the hyphal growth with formation of numerous haustoria within the mesophyll cells was subsequently followed by profuse sporulation in the absence of host cell necrosis on both wild-type and mutant accessions. TEM observations revealed that coenocytic intercellular hyphae ramified and spread intercellularly throughout the host tissue forming several haustoria in host mesophyll cells. Intracellular haustoria were lobed with the diameter of 6,7 ,m. Each haustorium was connected to intercellular hyphae in the absence of apparent haustorial neck. The cytoplasm of the haustorium included the organelles characteristic of the pathogen. Callose-like deposits were frequently observed at sites of penetration around the proximal region of the haustorial neck. Apart from a few callose ensheatments, no obvious response was observed in host cells following formation of haustoria. Most of mesophyll cells contained normal haustoria and the host cytoplasm displayed a high degree of structural integrity. Absence of host cell wall alteration and cell death in penetrated host cell of both accessions suggest that the pathogen exerts considerable control over basic cellular processes and in this respect, response to this biotroph oomycete differs considerably from responses to other pathogens such as necrotrophs. [source] In Situ Transmission Electron Microscopy of Electric Field-Triggered Reversible Domain Formation in Bi-Based Lead-Free PiezoceramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Jens Kling A lead-free piezoelectric 0.91(Bi1/2Na1/2)TiO3,0.06BaTiO3,0.03(K0.5Na0.5)NbO3 ceramic with high strain was examined in situ under an applied electric field using the transmission electron microscope. No domain structure is observed without an electric field, but an alternating electric field leads to the reversible formation of a lamellar domain structure. Correlations to polarization and strain hysteresis loop measurements indicate an electric field-induced phase transition from a nonpolar to a ferroelectric state and vice versa. [source] On the Lamellar Crystal Structure of Nylons 6,8 and 8,10: A Study Combining Electron Microscopy and Energy AnalysisMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 1 2003Marta Bermúdez Abstract Lamellar crystals of nylon 6,8 and nylon 8,10 with chains in a fully extended conformation were obtained by crystallization in solution, and examined by electron and X-ray diffraction. The same crystal structure appeared to be shared by both nylons crystallized in glycerin. This structure consisted of a mixture of ,- and ,-forms with features similar to that previously described for lamellar crystals of nylon 4,6 grown in the same solvent. Crystallization of nylon 8,10 in hexane-2,5-diol afforded lamellar crystals with sheets stacked in the ,-form. A comparative energy evaluation of the different models that are feasible for the crystal structure of these nylons with fully extended chains indicated very small energy differences among them. The presence of different chain arrangements in the same lamellar crystal, as well as the crystallization of the same nylon in different crystal forms upon slight modification of the crystallization conditions, are fully consistent, therefore, with the results obtained in the energy analysis. Nylon 8,10 crystals grown in hexane-2,5-diol at 150,°C. Inset: The respective electron diffraction patterns. [source] Characterization of HDPE /Polyamide 6/ Nanocomposites Using Scanning-and Transmission Electron MicroscopyMACROMOLECULAR SYMPOSIA, Issue 1 2007Eleonora Erdmann Abstract Summary: Preparation and morphology of high density polyethylene (HDPE)/ polyamide 6 (PA 6)/modified clay nanocomposites were studied. The ability of PA 6 in dispersing clays was used to prepare modified delaminated clays, which were then mixed with HDPE. Mixing was performed using melt processing in a torque rheometer equipped with roller rotors. After etching the materials with boiling toluene and formic acid at room temperature, the morphology was examined by SEM analyses, showing that the PA 6 formed the continuous phase and HDPE the dispersed phase. X-ray diffraction patterns show that the (001) peak of the clay is dramatically decreased and shifted to lower angles, indicating that intercalated/exfoliated nanocomposites are obtained. TEM analyses confirmed the typical structure of exfoliated nanocomposites. A scheme for the mechanism of exfoliation and/or intercalation of these HDPE /PA 6/ /organoclay nanocomposites is proposed. [source] Effect of EPDM on Morphology, Mechanical Properties, Crystallization Behavior and Viscoelastic Properties of iPP+HDPE BlendsMACROMOLECULAR SYMPOSIA, Issue 1 2007Nina Vranjes Abstract Summary: Blends of isotactic polypropylene (iPP) and high density polyethylene (HDPE) with and without ethylene-propylene-diene (EPDM) terpolymer as compatibilizer were systematically investigated to determine the influence of the EPDM on blends properties. The morphology was studied by Scanning Electron Microscopy (SEM). Mechanical properties of investigated systems: tensile strength at break, elongation at break, yield stress and Izod impact strength were determined. Crystallization behavior was determined by Differential Scanning Calorimetry (DSC). Dynamic Mechanical Analysis (DMA) was used to determined the storage modulus (E,), loss modulus (E,), and loss tangent (tan ,). The PP+HDPE blend revealed poor adhesion between PP and HDPE phases. Finer morphology was obtained by EPDM addition in PP+HDPE blends and better interfacial adhesion. Addition of HDPE to PP decreased tensile strength at break, elongation and yield stress. Decrease of tensile strength and yield stress is faster with EPDM addition in PP+HDPE blends. Elongation at break and impact strength was significantly increased with EPDM addition. The addition of EPDM in PP+HDPE blends did not significantly change melting points of PP phase, while melting points of HDPE phase was slightly decreased in PP+HDPE+EPDM blends. The EPDM addition increased the percentage of crystallization (Xc) of PP in PP+HDPE blends. The increase of Xc of HDPE was found in the blend with HDPE as matrix. Dynamical mechanical analysis showed glass transitions of PP and HDPE phase, as well as the relaxation transitions of their crystalline phase. By addition of EPDM glass transitions (Tg) of HDPE and PP phases in PP+HDPE blends decreased. Storage modulus (E,) vs. temperatures (T) curves are in the region between E,/T curves of neat PP and HDPE. The decrease of E, values at 25,°C with EPDM addition in PP+HDPE blends is more pronounced. [source] Use of the Surfmer 11-(Methacryloyloxy) undecanylsulfate MET as a Comonomer in Polystyrene and Poly(methyl methacrylate)MACROMOLECULAR SYMPOSIA, Issue 1 2004P.C. Hartmann Abstract The polymerizable surfactant sodium 11-(methacryloyloxy) undecanylsulfate (MET) has been synthesized with high purity, and its thermal stability and phase transitions have been studied by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. MET has been copolymerized in solution with methylmethacrylate (MMA) or styrene (S), initiated by azo-bis-isobutyronitrile (AIBN). The copolymers thus obtained have been studied by Gel Permeation Chromatography (GPC), Transmission Electron Microscopy (TEM), and DSC. Due to the incompatibility between the polar head of the MET units and the non polar S or MMA units, MET units organize in the amorphous polymer matrix and arrange in lamellar structures. [source] Borrelia burgdorferi membranes are the primary targets of reactive oxygen speciesMOLECULAR MICROBIOLOGY, Issue 3 2008Julie A. Boylan Summary Spirochetes living in an oxygen-rich environment or when challenged by host immune cells are exposed to reactive oxygen species (ROS). These species can harm/destroy cysteinyl residues, iron-sulphur clusters, DNA and polyunsaturated lipids, leading to inhibition of growth or cell death. Because Borrelia burgdorferi contains no intracellular iron, DNA is most likely not a major target for ROS via Fenton reaction. In support of this, growth of B. burgdorferi in the presence of 5 mM H2O2 had no effect on the DNA mutation rate (spontaneous coumermycin A1 resistance), and cells treated with 10 mM t -butyl hydroperoxide or 10 mM H2O2 show no increase in DNA damage. Unlike most bacteria, B. burgdorferi incorporates ROS-susceptible polyunsaturated fatty acids from the environment into their membranes. Analysis of lipoxidase-treated B. burgdorferi cells by Electron Microscopy showed significant irregularities indicative of membrane damage. Fatty acid analysis of cells treated with lipoxidase indicated that host-derived linoleic acid had been dramatically reduced (50-fold) in these cells, with a corresponding increase in the levels of malondialdehyde by-product (fourfold). These data suggest that B. burgdorferi membrane lipids are targets for attack by ROS encountered in the various stages of the infective cycle. [source] Order and Disorder in Powder Mixtures: Spatial Distribution Functions as Tools to Assess Powder HomogeneityPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 5-6 2008Albert Mihranyan Abstract In interactive mixtures with small carrier particles, the content variability is often higher than predicted by available models despite the significant degree of interaction visualized with Scanning Electron Microscopy (SEM). The present work details how pair-correlation functions can be used to reveal information about the spatial distribution of mixture constituents and their interactions. SEM pictures of a 2,% w/w oxazepam/sodium starch glycolate (SSG) mixture were recorded (n = 14). The constituent coordinates were extracted and pair-correlation functions as well as the cross-correlation function were calculated. A significant degree of interaction was observed between the constituents in the experimental mixture, compared to a randomized control system. In particular, the probability of finding an oxazepam particle was especially high inside the perimeter of the carrier particle and along its edges. The observed cross-correlation between oxazepam and SSG particles was periodic and repeated at distances corresponding to 1,1.5 carrier diameters. It was concluded that interactive mixtures of powders can be compared to disordered/amorphous solids since both exhibit short-range order, whilst lacking long-range translational periodicity. [source] Determination of Size Distributions of Concentrated Polymer Particles Embedded in a Solid Polymer MatrixPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 1 2008Ezequiel R. Soulé Abstract In this work we present the results obtained from the size characterization of polymer particles embedded in a solid polymer matrix using Static Light Scattering (SLS) and Scanning Electron Microscopy (SEM). The analyzed samples are the result of the solution polymerization of isobornyl methacrylate (IBoMA) in polyisobutylene (PIB) at complete conversion. Induced by polymerization, the system undergoes phase separation. As a result, spherical micron sized particles rich in PIB are formed. At the end of the polymerization, the particles become trapped in a solid polymer matrix rich in Poly-IBoMA. Size, concentration, and refractive index, make the resulting particle system scatter light under the Rayleigh-Debye-Gans (RDG) regime with interparticle interference. For Light Scattering (LS) characterization the samples are measured with a Flat Cell Static Light Scattering (FCSLS) apparatus, in which the reaction takes place. The resulting SLS spectra are analyzed using the Percus-Yevick approximation to model the interference effects. The local monodisperse approximation is used to consider polydispersity in the particle sizes. The estimated particle size distributions agree well with the measurements from SEM. In this work a concentrated particle system that naturally scatters light according to the RDG regime has been fully characterized in terms of its particle size distribution. This work, against the opinion of other authors, shows the feasibility of measuring still particles using a one dimensional array of light detectors. [source] Microstructured horizontal alumina pore arrays as growth templates for large area few and single nanowire devicesPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 2 2008Ying Xiang Abstract We demonstrate the fabrication of horizontally aligned and well-defined nanopore structures by anodic oxidation of aluminum thin films and micro stripes on a Si substrate. We are able to control both, the pore diameters and interpore distances from 10 nm to 130 nm and from 30 nm to 275 nm, respectively. The anisotropy of the system induces some deviations in the pore configuration from the typical honeycomb structure. By decreasing the dimensions of the Al structures, the final pore diameter and interpore distance remains constant, enabling the transition from multiple to a few nanowire porous structures. Finally, we successfully filled the nanopores by pulsed electroplating, as demonstrated both by Scanning Electron Microscopy and by current,voltage measurements. Having full control over the size, the density, the position and the orientation of the porous structure, our approach is promising for many exciting applications, including nanoelectronics and sensing. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis of nickel,zinc ferrite nanoparticles in polyol: morphological, structural and magnetic studiesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2006Z. Beji Abstract Nickel,zinc ferrite monodisperse nanoparticles are synthesized by forced hydrolysis in diethylenglycol. FC and ZFC susceptibility curves suggest that they present superparmagnetic behaviour with a blocking temperature between 63 and 15 K depending on the zinc content. The saturation magnetization of the nanocrystals at 5 K is very close to that of bulk materials, and very high compared to that of similar particles prepared by other chemical routes. High Resolution Transmission Electron Microscopy and In-field Mössbauer studies show clearly that these relatively high values are mainly due to: (i) the high crystalline quality of the particles and (ii) a cation distribution different from the classical distribution encountered in the bulk material. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] HRTEM, Raman and optical study of CdS1,xSex nanocrystals embedded in silicate glassPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 13 2004V. Bellani Abstract We studied CdS1,xSex nanocrystals embedded in a silicate glass by means of complementary techniques like high resolution transmission electron microscopy (HRTEM), micro-Raman spectroscopy and optical transmission and reflectivity. Transmission Electron Microscopy gives complete information on crystallization and size distribution of the nanocrystals wile Raman scattering is particularly useful in the determination of the composition of the nanocrystals for low-concentration or small-crystallite size composite. Having the size distribution and composition of the nanocrystals we have explained the transmission spectra of the studied samples. Optical transmission spectra evidence the quantization of the electronic states of the nanoparticles system with a size distribution described by a Gaussian function. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Carbon nanotube probe resolution: a quantitative analysis using Fourier TransformPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2004H. R. Gutiérrez Abstract A method to quantify the resolution of atomic force microscopy (AFM) probes using Fourier analysis of the AFM images is proposed. The maximum detectable spatial frequency obtained from the power spectrum was used to estimate the lateral resolution. Carbon nanotube tips were successfully used to study very dense arrays of semiconductor nanostructures. In particular, accurate measurements of shallow facet angles were obtained, which are in perfect agreement with results obtained by two complementary techniques , High Resolution Transmission Electron Microscopy and Reflection High-Energy Electron Diffraction. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Study of metal-oxide-semiconductor capacitors with r.f. magnetron sputtering TiOxNy films dielectric layerPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Katia Franklin Albertin Abstract A set of MOS capacitors with TiOxNy films as gate dielectric layer was fabricated and characterized. The TiOxNy films were deposited by reactive r.f. magnetron sputtering varying the nitrogen and oxygen partial pressure in a Ar/N2/O2 gaseous mixture. The TiOxNy films were characterized by, Rutherford Backscattering (RBS), X-ray absorption near edge spectroscopy (XANES) in oxygen K-edge (O-K), optical absorption and High Resolution Transmission Electron Microscopy (HRTEM). Capacitance-voltage (1MHz) and current-voltage measurements were performed to obtain the effective dielectric constant, the effective oxide thickness (EOT), the leakage current density, and the interface quality. MOS capacitors results show that the TiOxNyfilms dielectric constant varies from 28 to 80, present a good interface quality with silicon, and the leakage current density values are in the order of 0.25 mA/cm2 for VG = ,2V, which is acceptable for high performance logic circuits and low power circuits fabrication. The leakage current density is reduced in 2 orders of magnitude for increasing nitrogen concentration (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spontaneous stratification of InGaN layers and its influence on optical propertiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009Z. Liliental-Weber Abstract Transmission Electron Microscopy, high resolution X-ray diffraction and reciprocal space maps, Rutherford Back Scattering and photoluminescence were applied to study InGaN layers grown by MOCVD with increasing layer thickness (100 nm to 1000 nm) and nominally constant In concentration of 10%. Spontaneous stratification of the layer has been found. A strained layer with lower than nominal In content was found in direct contact with the underlying GaN followed by relaxed layers with a nominal or higher In concentration. A high density of randomly distributed stacking faults as well as domains with cubic structure and closely distributed stacking faults (polytype-like) were present in the thicker layers. Strong corrugation of the thicker sample surface was observed. The appearance of multiple photoluminescence line positions was related not only to the spontaneously formed layers with different In content, but also to the structural planar defects formed in the thicker layers. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||||||||||||||||||||