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SEM Images (sem + image)
Selected AbstractsSmall Wonder: Using SEM Images to Exhibit the "Small Stuff"CURATOR THE MUSEUM JOURNAL, Issue 3 2009Alwynne B. Beaudoin In 2007, the Royal Alberta Museum held an exhibition of 28 SEM (scanning electron microscope) images of seeds and other subfossil macroremains, which were shown in a fine-art format. The exhibition was prepared by a museum team using images derived from in-house curatorial research work. This paper describes the exhibition components and reports on an attempt to engage the visitors more closely with the images by asking them to suggest identifications for some "mystery" specimens. [source] Preparation and Characterization of Uniformly Sized Sub-micrometer Spherical Silica/Organic Polymer Hybrid ParticlesADVANCED ENGINEERING MATERIALS, Issue 9 2003X.-s. Xing Hybrid particles with a core-shell structure, consisting of a silica core and a polyvinyl alcohol (PVA) shell, (see Figure for an SEM image of a particle material of this type), were fabricated via a two-step sol-gel process. The PVA molecular chains are probably physically adsorbed onto the surface of silica cores by hydrogen bonds and van der Waals forces. [source] Hot-Pressed Glass Matrix Composites Containing Pyrochlore Phase Particles for Nuclear Waste Encapsulation,ADVANCED ENGINEERING MATERIALS, Issue 7 2003A.R. Boccaccini As alternative immobilization materials for Pu-bearing nuclear waste, lead-containing glass matrix composites with homogeneously distributed lanthanum zirconate pyrochlore particles (up to 30,% by volume) have been developed. Fabrication by hot pressing at the relatively mild temperature of 610,°C leaves the pyrochlore structure of the La zirconate unchanged, which is crucial for the containment of radioactive nuclei. The Figure, an SEM image of a polished sample with 30,% La2Zr2O7, demonstrates the homogeneous particle distribution and absence of pores. [source] Beneficial Effects of AlN as Sintering Aid on Microstructure and Mechanical Properties of Hot-pressed ZrB2,ADVANCED ENGINEERING MATERIALS, Issue 7 2003F. Monteverde Higher density of ZrB2 ceramics than with the pure material is achieved when 4.6,% of aluminum nitride are added before hot-pressing as a sintering aid. AlN supports densification and prevents grain coarsening, mainly by virtue of its ability to remove the boron oxide layer that otherwise covers ZrB2 particles. The new material (see Figure for an SEM image of a polished section) has outstanding mechanical properties, e.g. strength values of 600 and 200 MPa at 25 and 1500,°C. [source] Modeling of Environmental Degradation in Fatigue-Life Prediction of Near-, Titanium Alloy IMI 834 under Complex High-Temperature Loading Conditions,ADVANCED ENGINEERING MATERIALS, Issue 6 2003R.G. Teteruk The crack propagation model successfully applies to life-prediction of near-,-titanium alloy IMI 834 under complex high-temperature fatigue-loading conditions. The predictive capabilities of the model can be attributed to the close correlation of the model with the relevant damage mechanisms (among them environmental degradation under varying conditions) and micro-structural processes. The Figure shows an SEM image of a typical crack-initiation site for a test run at 400,°C. [source] Nanocomposite Synthesis: Embryonic States of Fluorapatite,Gelatine Nanocomposites and Their Intrinsic Electric-Field-Driven Morphogenesis: The Missing Link on the Way from Atomistic Simulations to Pattern Formation on the Mesoscale (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Mater. Fractal aggregates of fluorapatite,gelatine nanocomposites (SEM image taken by Yigit Öztan, MPI CPfS),which bears a strong resemblance to the biosystem hydroxyapatite,collagen, a key material in human bones and teeth,are formed from bundles of calcified protein molecules representing the first (embryonic) states of shape development and leading to extended processes of self-organisation. This process has been studied in detail by P. Simon et al., and is reported on page 3596. [source] Photovoltaic Devices: High-Efficiency Solar Cell with Earth-Abundant Liquid-Processed Absorber (Adv. Mater.ADVANCED MATERIALS, Issue 20 201020/2010) The image shows a thin-film solar cell, deposited from a hybrid solution-nanoparticle ink, with a background scanning electron microscopy (SEM) image of the zinc-compound particle component of the ink. A cross-sectional SEM image of the device shows the large-grained kesterite absorber layer composed of readily available elements: Cu-Zn-Sn-S-Se. The solution-processed devices offer record power conversion efficiency for kesterite absorber layers, as presented by D. B. Mitzi et al. on page E156. [source] Vertical Transistor with Ultrathin Silicon Nitride Gate DielectricADVANCED MATERIALS, Issue 44 2009Maryam Moradi Nanoscale vertical thin-film transistors (VTFTs) are fabricated employing a new ultrathin silicon nitride (SiNx) gate dielectric for applications in high-resolution active matrix flat panel electronics. Illustrated are the cross-section schematic and SEM image of a 500,nm channel length VTFT with a 50,nm thick SiNx gate dielectric. The device demonstrates excellent gate control with gate leakage as low as 0.1,nA cm,2. [source] Expanded Graphite: One-Step Exfoliation Synthesis of Easily Soluble Graphite and Transparent Conducting Graphene Sheets (Adv. Mater.ADVANCED MATERIALS, Issue 43 200943/2009) The inside cover shows an SEM image of easily soluble expanded graphite (ESEG) on a Si substrate. In work by Ji-Beom Yoo and co-workers (p. 4383) the ESEG was prepared from a fluorinated graphite intercalation compound (FGIC),C2F,·,nClF3. The inset scheme shows the fluorinated graphite intercalation compound. Due to the severe expansion state, the ESEG can be dispersed in organic solvents or even water by ultrasonication with common surfactants. [source] Self-Assembly of Ordered Semiconductor Nanoholes by Ion Beam SputteringADVANCED MATERIALS, Issue 28 2009Qiangmin Wei Periodic nanohole arrays are formed on a Ge substrate by self-assembly using focused ion beam sputtering at normal incidence with an energy of 5,keV. The figure shows an SEM image of a hexagonally ordered hole domain that has hexagonally ordered quantum dots,20,nm diameter and 3,nm height,around each hole The structured Ge has high surface area and a considerably blue-shifted energy gap. [source] Nonclassical Crystallization: Facile Synthesis and Shape Evolution of Single-Crystal Cuprous Oxide (Adv. Mater.ADVANCED MATERIALS, Issue 20 200920/2009) Lian Gao and co-workers discuss on p. 2068 the synergic effect of oriented attachment and ripening mechanism with face-selective additive adsorption for the formation of various morphologies of single-crystal Cu2O. The frontispiece shows an SEM image of self-assembled microcubic Cu2O mesocrystals, clearly revealing the rarely observed combination of a nonclassical-particle-based crystallization process and subsequent classical crystallization process. [source] Bioinspired Degradable Substrates with Extreme Wettability PropertiesADVANCED MATERIALS, Issue 18 2009Wenlong Song Robust superhydrophobic poly(L -lactic acid) (PLLA) substrates are prepared using a new phase-separation-based method. The wettability of the surfaces can be controlled in the range from superhydrophobic to superhydrophilic using argon-plasma treatment. The figure shows water droplets with different contact angles on differently modified PLLA surfaces superimposed on a SEM image of a rough surface. [source] Self-Healing Polymers: Self-Healing Polymer Coatings (Adv. Mater.ADVANCED MATERIALS, Issue 6 20096/2009) Dramatic reduction in corrosion of a steel plate coated with a self-healing coating (right) as compared to a conventional coating is demonstrated. Two samples were scratched and placed in 5% NaCl for 5 days. The background is an optical image (2× magnification), in the foreground is an SEM image of the scratch. In the self-healing sample, the scratch has almost completely self-healed, while in the control sample, the scratch remains all the way down to the substrate, as reported by Paul Braun and co-workers on p.645. [source] Nanostructured Materials: Microstructural and Biochemical Characterization of the Nanoporous Sucker Rings from Dosidicus gigas (Adv. Mater.ADVANCED MATERIALS, Issue 4 20094/2009) The cover image shows an SEM image of a squid tentacle, revealing the individual sucker rings. These toothed ringlike structures within the suckers provide additional gripping power during prey capture and handling. The background image depicts the nanoscale network of parallel tubular elements from which the rings are constructed. The structural, mechanical and biochemical properties of this wholly organic material is discussed in detail by David Kisailus, Henrik Birkedal, and co-workers on p. 401. [source] Nanofiber organic semiconductors: The effects of nanosize on the electrical charge transport and optical properties of bulk polyanilinesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2009F. Yakuphanoglu Abstract The electrical transport, optical, and microstructural properties of bulk polyaniline (PANI) and nano-PANIs were investigated. A field emission scanning electron microscopy (SEM) image of bulk PANI showed macroscopic and aggregated granular particles. A SEM image of the nanostructured PANI showed the formation of one-dimensional nano/microstructures. The formation of nanofibers was observed from the transmission electron microscopy image. The electrical conductivities of the bulk and nanostructured PANIs increased with increasing temperature, which indicated semiconductor behavior. The electrical conductivities of the bulk and nanostructured PANIs at room temperature were found to be 2.12 × 10,5 and 1.80 × 10,2 S/cm, respectively. The electrical conductivity of the nanostructured PANI was about 850 times higher than that of the bulk PANI. The obtained band gaps of the bulk and nanostructured PANIs were determined from diffuse reflectance measurements and were found to be 3.27 and 2.41 eV, respectively. The refractive index of the PANI samples changed from 1.3 to 1.61. The obtained results indicate that the electrical and optical properties of the PANI were inherently dependent on the nanostructure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] A Study on Biomineralization Behavior of N -Methylene Phosphochitosan ScaffoldsMACROMOLECULAR BIOSCIENCE, Issue 10 2004Yu Ji Yin Abstract Summary: Biomimetic growth of calcium phosphate over natural polymer may be an effective approach to constituting an organic/inorganic composite scaffold for bone tissue engineering. In this work, N -methylene phosphochitosan (NMPCS) was prepared via formaldehyde addition and condensation with phosphoric acid in a step that allowed homogeneous modification without obvious deterioration in chitosan (CS) properties. The NMPCS obtained was characterized by using FT-IR and elemental analysis. The macroporous scaffolds were fabricated through a freeze-drying technique. A comparative study on NMPCS and CS scaffold biomimetic mineralization was carried out in different media, i.e, a simulated body fluid (SBF) or alternative CaCl2 and Na2HPO4 solutions respectively. Apatite formation within NMPCS and CS scaffolds was identified with FT-IR, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffractometery (XRD). The results revealed alternate soaking of the scaffolds in CaCl2 and Na2HPO4 solutions was better than soaking in SBF solution alone in relation to apatite deposition on the scaffold pore walls. Biomineralization provides an approach to improve nature derived materials, e.g., chitosan derivative NMPCS properties e.g., compressive modulus, etc. SEM image of a NMPCS/apatite composite scaffold. [source] Morphology and Crystalline Structure of Poly(, -Caprolactone) Nanofiber via Porous Aluminium Oxide TemplateMACROMOLECULAR MATERIALS & ENGINEERING, Issue 9 2006Yang Chen Abstract Summary: Poly(, -caprolactone) (PCL) nanofibers with a dimension of about 150 nm were successfully fabricated by using a process of extruding PCL solution via a porous aluminium oxide template and then solidifying in methanol. The morphology, melting behavior and crystalline structure of the nanofibers were investigated by using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results revealed that the weight-average molecular weight () of PCL hardly influenced the morphology of the nanofibers. However, the melting temperature (Tm) of the PCL crystalline increased slightly from 55.4 to 57.5,°C with an increase in . The accessional pressure and the presence of the porous template played an important role in the improvement of the orientation and crystallization structures of the polymer chains when they were passing through the nano-scale porous channel, leading to the conglomeration of the fiber and the much larger diameter than those from the pressure-induced extrusion process. Furthermore, comparing the processes with and without accessional pressure, the crystallinity of the nanofibers obtained under 0.2 MPa pressure increased, and the diffraction for the (001) lattice plane occurred. SEM image of PCL nanofibers extruded via a porous aluminium oxide template with the aid of pressure. [source] The Influence of Solvent Properties and Functionality on the Electrospinnability of Polystyrene NanofibersMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2006Cattaleeya Pattamaprom Abstract Summary: In order to produce nanometer-sized fibers at an industrial scale, not only the morphology but also the production rate of fibers is important. The effect of solvent properties and functionality on the production rate of electrospun PS nanofibers was investigated using eighteen different solvents. The solution concentration was varied between 10 and 30% w/v. Electrospinning of PS solutions was carried out at various applied voltages and tip-to-collector distances The production rate of the obtained PS nanofibers was quantified in terms of electrospinnability. We found that the chance for the resulting PS solution to be spinnable is greater for solvents with high dipole moment and low viscosity. The solvent that provided the highest electrospinnability for polystyrene was DMF and the functionalities that promoted high dipole moment and thus high spinnability were the carbonyl group and the nitrogen group with free electrons. General guidelines for choosing suitable solvents for successful production of electrospun nanofibers have also been proposed. SEM image of PS 685D at 200× magnification and the %-coverage of the fibers obtained by using DMF, chloroform, and 1,4-dioxane. [source] Polymeric Toughening of Particle Filled Cyanate Ester CompositesMACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005Tim J. Wooster Abstract Summary: The present study examines the effect of polymeric tougheners on the performance of silica filled cyanate ester composites. The polymeric tougheners used have been shown to enhance cyanate ester tougheners in binary toughener/matrix systems. Tougheners that were able to form a favourable phase-separated morphology resulted in the greatest increase in crack resistance. The addition of these tougheners resulted in minimal loss of strength, and a slight decrease in modulus. Importantly the viscosity of the compounded systems was low enough for them to be readily processable. Whilst conserving most secondary properties, toughener addition did result in a slight increase in composite hydrolytic degradation. This issue was linked to the additive/ additive compounding processes. Removal of this extra moisture should eliminate this concern, permitting the used of these composites in electronic applications. Effect of ETBN content on the crack resistance of particle filled cyanate ester composites and SEM image of 15 matrix wt.-% ETBN. [source] Structure and Mechanical Properties of Polyurethane/Silica Hybrid CoatingsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005Yongchun Chen Abstract Summary: Polyurethane/silica hybrid coatings were prepared via in situ (IS) or blending (BL) method using different acidic silica sols. The effects of preparation methods, silica types, and content on the structure and mechanical properties of the hybrid coatings were investigated. It was found that there existed two types of silica phases in the hybrid coatings: silica-rich agglomerate and primary silica-rich phase, whose size and compactness depended upon the silica types and the preparation methods. Introducing silica could result in obvious changes in surface free energy, atomic composition, and mechanical properties of the hybrid coatings. Typical SEM image of the fractured surface of hybrids obtained by the in situ method. [source] A Novel Route to Multiphase Polymer Systems Containing Nano-Droplets: Radical Polymerization of Vinylic Monomers in Gelled Water-in-Oil MiniemulsionsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 10 2005Christian Holtze Abstract Summary: A new strategy for the synthesis of composite polymers with larger volume fraction of aqueous inclusions less than 1 µm in diameter is presented. A water-in-oil miniemulsion of aqueous droplets in a continuous, cross-linkable monomer phase is prepared. The addition of an organo-gelator allows the immobilization of the droplets in a solid gel, thus avoiding the usual demixing upon polymerization of the continuous phase. This pregelled system is then converted into a composite polymer by photoinitiated free radical polymerization. Such coatings may be used for an improved climate control of buildings or as a deposit for the controlled release of actives from polar nano-droplets. SEM image of a cross-linked composite polymer showing controlled droplet inclusions with a maximal diameter of 500 nm. [source] Non-Fluorous Random Copolymeric Stabilizers for Dispersion Polymerizations of MMA in Supercritical CO2MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2006Ha Soo Hwang Abstract Summary: The dispersion polymerization of MMA in supercritical CO2 was successfully carried out utilizing the first non-fluorous random copolymers composed of 3-tris(trimethoxysilyl)propyl methacrylate and 2-dimethylaminoethyl methacrylate, poly(SiMA- co -DMAEMA) as a stabilizer. The resulting high yield (>93%) of micron-sized PMMA was formed in the presence of 5% (w/w to MMA) of copolymeric stabilizers. While the PSiMA and PDMAEMA homopolymer produced nondescript solid and irregular shape aggregate, respectively, the random copolymer of 71% SiMA-content resulted in spherical and uniform powder. SEM image of PMMA particles prepared in supercritical CO2 using poly(SiMA- co -DMAEMA) (71:29) stabilizer. [source] Introducing a Flat Model of the Silica-Supported Bis(imino)pyridyl Iron(II) Polyolefin CatalystMACROMOLECULAR RAPID COMMUNICATIONS, Issue 4 2006Wei Han Abstract Summary: A well-defined flat model of a supported homogeneous polyolefin catalyst is prepared on the basis of an immobilized bis(imino)pyridyl iron complex on a super flat silica surface. The amount of supported catalyst precursor is quantified using XPS. This model catalyst remains active over extended periods, i.e., an average activity of 0.25,×,103 kg PE,·,(molCat,·,h,·,bar),1 is obtained for 24 h of ethylene polymerization. The morphology of the nascent polyethylene film is investigated by SEM. A side-view SEM image of the PE produced from the supported bis(imino)pyridyl Fe catalyst. [source] Polyelectrolyte Multilayer Microspheres as Carriers for Bienzyme System: Preparation and CharacterizationMACROMOLECULAR RAPID COMMUNICATIONS, Issue 14 2005Nadezda G. Balabushevich Abstract Summary: Polyelectrolyte multilayer microspheres were prepared by alternating adsorption of dextran sulfate and protamine on melamine formaldehyde cores followed by the partial decomposition of the core. Peroxidase and glucose oxidase were immobilized in the prepared microspheres. Retention of enzymatic activity of the peroxidase/glucose oxidase system incorporated into the microspheres was demonstrated. Applicability of the bienzyme system immobilized in the microspheres for kinetic glucose assay was shown. SEM image of the polyelectrolyte multilayer microsphere. [source] Fabrication of Biomimetic Superhydrophobic Coating with a Micro-Nano-Binary StructureMACROMOLECULAR RAPID COMMUNICATIONS, Issue 13 2005Ning Zhao Abstract Summary: A superhydrophobic coating was facilely fabricated in one step by casting bisphenol A polycarbonate (PC) solution under moisture. Vapor-induced phase separation occurred during the solidifying process and a rough surface with a micro-nano-binary structure (MNBS) similar to the microstructure shown on lotus leaf was formed. SEM image of a single micro-flower. [source] Selective Electroless Deposition of Cu on an Ultrathin Au Film PatternMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2004Maofeng Zhang Abstract Summary: In this report an ultrathin Au nanoparticle (AuNP) film composed of photosensitive diazoresin (DR) and mercaptophenol (MP) capped AuNPs (MP-AuNPs) was fabricated by self-assembly (SA). The DR/MP-AuNP film was then patterned through a photomask by selective exposure to UV light and instantly developed in sodium dodecyl sulfate (SDS) aqueous solution. After sintering at 550,°C to remove the organic components, the DR/MP-AuNPs formed AuNPs. Taking advantage of the catalytic susceptibility of AuNPs toward electroless deposition of Cu, a Cu film micropattern with fine resolution (ca. 2,3 ,m) and considerable thickness (ca. 130 nm) was prepared. SEM image of the micropatterned Cu film on a silicon substrate; scale bar: 10 ,m. [source] Polymer Nanocomposites Using Urchin-Shaped Carbon Nanotube-Silica Hybrids as Reinforcing FillersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 21 2004Wei-De Zhang Abstract Summary: Carbon nanotubes (CNTs) have been grown on MCM-41 supported Fe nanoparticles and the as-prepared (no further purification) CNT-silica hybrid was directly incorporated into nylon-6 (PA6) by simple melt-compounding. The urchin-shaped CNT-silica hybrid filler was observed to be homogeneously dispersed throughout the matrix by scanning electron and transmission electron microscopy. Compared with neat PA6, the tensile modulus and strength of the composite are greatly improved by about 110%, with incorporation of only 1 wt.-% CNT-silica filler. SEM image and schematic representation showing polymer chains wrapping around the urchin-shaped CNT-silica hybrid filler. [source] A Novel, Facile Method for the Preparation of Uniform, Reactive Maleic Anhydride/Vinyl Acetate Copolymer Micro- and NanospheresMACROMOLECULAR RAPID COMMUNICATIONS, Issue 17 2004Chang-Min Xing Abstract Summary: A novel, stabilizer-free dispersion polymerization with alkyl esters as reaction media gives uniform alternating microspheres of maleic anhydride (MAn)/vinyl acetate (VAc) copolymer. The diameter of the copolymer microspheres could be precisely controlled from 80 to 750 nm by changing the monomer concentration or feed ratio. Moreover, this new type of copolymer microspheres with reactive anhydride groups on the surface has good solubility in common nontoxic solvents such as water and ethanol. SEM image of the powder surface of copolymer microspheres formed at [MAn],=,[VAc],=,1.5 M. [source] Performance of Impedimetric Biosensors Based on Anodically Formed Ti/TiO2 ElectrodesELECTROANALYSIS, Issue 20 2005Aikaterini Abstract The advantages and limitations of impedimetric sensors based on Ti/TiO2 architectures are described. Titanium dioxide (titania) was potentiostatically formed onto titanium electrodes of 2,mm diameter, at 10 and 30,V in 1,M H2SO4. The thickness of the titania layers was ellipsometrically determined to be 30 and 86,nm respectively and they are highly insulating with charge-transfer resistances in the M, range, as they were measured with electrochemical impedance spectroscopy under specific experimental conditions. Low voltage anodization (<10,V) results to amorphous TiO2, whereas at higher applied voltages (>25,V), anatase is the predominant form. SEM images are indicative of quite smooth, compact coatings without any severe cracks. [source] Photonic Crystals: Patterned Polymeric Domes with 3D and 2D Embedded Colloidal Crystals using Photocurable Emulsion Droplets (Adv. Mater.ADVANCED MATERIALS, Issue 37 200937/2009) The inside cover shows a scheme for the preparation of photonic dome patterns, SEM images of a dome pattern, and a single dome decorated with 2D colloid array, as fabricated in work reported on p 3771 by Seung-Man Yang and co-workers. The background is an optical microscopy image of patterned photonic domes, which can be used as a near-field microlens array. The greenish color of the domes corresponds to the photonic bandgap. [source] | ||||||||||||||||||||||||||||||||||||||||