bluuebunny/crossref_metadata_2025_split huggingface dataset:
On superperiodic features on highly oriented pyrolytic graphite
Authors: Feddes B. , Kravchenko I. I. , Seiberling L. E. 
Published: June 2010

AbstractWe present scanning tunneling microscopy (STM) results that show the superstructure on the highly oriented pryrolytic graphite (HOPG) surface. The superlattice appears to be the result of an apparent twist boundary dislocation. The crucial point of the observation is that the superlattice changes simultaneously its constant from 18 to 72 nm when we go around the screw dislocation in the plane perpendicular to the dislocation vector. Based on available models of the graphite surface top layers, we are able to simulate observed STM images. Our STM observation of the superstructure lattice, whose lattice constant varies continuously, gives strong evidence that the superlattice is of Moiré pattern nature, but a correct model can be built only if the graphite electronic structure is taken into consideration.
Monte Carlo simulation of charging effects on linewidth metrology
Authors: Ko Yeong‐Uk , Chung Myung‐Sae , Kim Seung‐Woo 
Published: June 2010

AbstractCharging effects of scanning electron microscopes on the linewidth metrology of polymethylmethacrylate (PMMA) insulatorpatterns are investigated using Monte Carlo simulation. It is first revealed in detail how the nonunity yield of electron generation in the PMMA target leads to local charge accumulation and affects the image profile of secondary electrons as charging develops. Then the measurement offset due to charging effects is identified for various target patterns of isolated and array types. Finally, it is concluded that the measurement uncertainty caused by the measurement offset exceeds the error budget limit that will be allowed in the linewidth metrology of the next generation of semiconductors.
Evaluation errors with dust measurements of laminar minerals by scanning electron microscope following German guideline VDI 3492
Authors: Hansgeorg Förster  , Doege Thomas 
Published: June 2010

AbstractA number of seemingly fibrous particles are found by evaluation of dust measurements of the industrial mineral vermiculite in accordance with German Guideline VDI 3492, part 2 for “measurements of inorganic fibrous particles‐ SEM method.” A more thorough investigation based upon an extension of the measuring method proves the nonfibrous morphology of practically all of these particles. The basic idea of this extension is to tilt the filter holder of the electron microscope and to check the exact orientation of the particles on the filter, an examination which is necessary to determine their true length and diameter. The result indicates that only very few fibrous particles actually exist. In the case of vermiculite, these fibrous particles are rolled up and detached flakes called “scrolls.” The systematic error inherent in VDI 3492, part 2, without extension can be quantified in the case of vermiculite to have a factor > 50, that is, fibre counts obtained are more than 50 times too high.
The structure and thermal stability of tungsten‐based contact metallizations to n‐GaN
Authors: Cole M. W. , Ren F. , Pearton S. J. 
Published: June 2010

AbstractThermally stable contacts to n‐GaN have been obtained using W and WSi. Low specific contact resistance was achieved for the W metallization with limited reaction between the metal and semiconductor up to 1000°C. The formation of the β‐W2N and W‐N interfacial phases were deemed responsible for the electrical integrity observed at these annealing temperatures. The Wx‐N1‐x interfacial phases functioned as efficient barriers to the outdiffusion of Ga. For WSi, the β‐W2N interfacial phase formation was observed after annealing at 700° and 800°C. This phase also prevented Ga outdiffusion at these elevated temperatures. Optimization of this phase and moderate suppression of interfacial irregularities occurred after annealing at 800°C. This investigation demonstrates that both W and WSi contacts appear to be reasonable contact choices for high‐temperature electronics applications.
Applications of high‐speed confocal imaging techniques in operative dentistry
Authors: Watson Timothy F. 
Published: June 2010

AbstractAll confocal scanning optical microscopes are suitable for making high‐resolution images of many structures in teeth under near normal conditions. If the microscope can operate at high speed, then the number of applications widens considerably. The high‐frame speed of the tandem scanning reflected light microscope (TSM) enables real‐time examination of teeth in vivo, especially when the microscope is configured with a stabilising objective, featuring internal focusing elements. Experimental procedures examined microscopically on extracted teeth can include the cutting of the hard tissues, observation of fluid flow in dentine, the application of adhesives, and the fracturing of adhesive interfaces under load. Undertaking experiments where time is an important function has improved our knowledge of many of the materials/substrate interactions involved in dental operative procedures. Storing images on media other than video tape can be expensive, but reductions in the cost of computer memory is making digitisation and storage of images in real‐time more widely available.
Real‐time confocal microscopy of keratocyte activity in wound healing after cryoablation in rabbit corneas
Authors: Chew S. J. , Beuerman R. W. , Kaufman H. E. 
Published: June 2010

AbstractA modified tandem scanning confocal microscope was used for real‐time in vivo examination of the rabbit cornea following a cryogenic injury. The corneas of New Zealand white rabbits were frozen with aprobe that had been cooled by immersion in liquid nitrogen, effectively destroying keratocytes in a central 5 mm diameter zone throughout the total thickness of the cornea. In these eyes, keratocyte repopulation and corneal stromal wound healing proceeded similarly to that which occurs after epikeratophakia, a refractive surgical procedure designed to change the curvature and optical power of the cornea. In epikeratophakia, a cryolathed donor corneal stroma lenticule is sutured onto the bare stroma of the recipient cornea. The collagen tissue lenticule is repopulated by keratocytes (corneal fibroblasts) that migrate in from the host cornea. In our study, the confocal microscope permitted sequential, noninvasive examination of the corneal stroma in the treated animals. Necrosis of the keratocytes, followed by activation of the remaining viable cells in the corneal periphery, was observed in the first 2 to 3 days after cryo injury. A fine stromal fibrous network was seen to develop; in three eyes, this network progressed to the development of a retrocorneal fibrous membrane and dense stromal fibrosis, both of which resulted in significant loss of corneal clarity. Our results suggest that the confocal microscope may be a valuable tool to provide much needed information on wound healing processes at the cellular level after corneal surgery and injury.
Improvement of thermally induced bending of cantilevers used for atomic force microscopy
Authors: Radmacher M. , Cleveland J. P. , Hansma P. K. 
Published: June 2010

AbstractThe microfabricated silicon nitride cantilevers that are used for atomic force microscopy (AFM) are, unfortunately, sensitive thermometers. They bend with ambient temperature changes and those due to laser heating. The bend can result in displacements for the silicon nitride cantilevers of an order several hundred nanometers at the tip of the cantilever. If, however, the silicon nitride cantilevers are treated by removing the metallization and annealing at 500°C for 30 min, these displacements can be reduced by one or two orders of magnitude. Silicon cantilevers have approximately a one order of magnitude smaller drift than silicon nitride cantilevers as received from vendors and are improved less by treatment.
Effects of brefeldin‐A on Golgi morphology in human cultured fibroblasts observed in three‐dimensional stereo scanning electron microscopy
Authors: So Derek Y. F. , Temkin Robert J. , Lea Peter J. 
Published: June 2010

AbstractBrefeldin A (BFA) has been reported to cause disassembly of the Golgi. We have used three‐dimensional (3‐D) high‐resolution scanning electron microscopy (HRSEM) to investigate these effects in human skin fibroblast cells. The spontaneous reassembly during prolonged exposure to BFA and some effects of forskolin were observed. A BFA concentration of 5μg/ml caused Golgi complexes to become vesicular, resulting in a progressive decrease in the size of the Golgi. Morphologic changes were visible within 2 min of BFA incubation, and by 30 min no identifiable Golgi could be found. Spontaneous reassembly of the Golgi apparatus upon the removal of the BFA or with continued long‐term exposure with BFA could not be confirmed. Preliminary experiments with forskolin were not effective in reversing or inhibiting the effects of BFA in human fibroblast cells grown in culture. This inability for spontaneous reassembly and nonreversal by forskolin may reflect a differential effect of BFA in various cell types. HRSEM has proven to be useful for observing 3‐D morphologic effects of BFA in Golgi.
Topographic and material contrast in low‐voltage scanning electron microscopy
Authors: Hejna J. 
Published: June 2010

AbstractTwo scintillation backscattered electron (BSE) detectors with a high voltage applied to scintillators were built and tested in a field emission scanning electron microscope (SEM) at low primary beam energies. One detector collects BSE emitted at low take‐off angles, the second at high takeoff angles. The low take‐off detector gives good topographic tilt contrast, stronger than in the case of the secondary electron (SE) detection and less sensitive to the presence of contamination layers on the surface. The high take‐off detector is less sensitive to the topography and can be used for detection of material contrast, but the contrast becomes equivocal at the beam energy of 1 keV or lower.
An annular toroidal backscattered electron energy analyser for use in scanning electron microscopy
Authors: Rau E. I. , Robinson V. N. E. 
Published: June 2010

AbstractA backscattered electron energy spectrometer, based on a toroidal energy analyser and an annular detector, has been devised and adapted for use in a scanning electron microscope. Computer simulations have been carried out for equipotentials and trajectories of electrons in the toroidal deflector, which permit the optimisation of the energy analyser characteristics for special applications. Based upon these results, a device has been built and its efficiency is demonstrated by selected images of a multilayered structure and a series of recorded backscattered electron spectra.
Three‐dimensional laser scanning two‐photon fluorescence confocal microscopy of polymer materials using a new, efficient upconverting fluorophore
Authors: Bhawalkar J. D. , Swiatkiewicz J. , Pan S. J. , Samarabandu J. K. , Liou W. S. , He G. S. , Berezney R. , Cheng P. C. , Prasad P. N. 
Published: June 2010

AbstractThree‐dimensional confocal imaging of polymer samples was achieved by the use of two‐photon excited fluorescence in both positive and negative contrast modes. The fluorophore was a new and highly efficient two‐photon induced upconverter, resulting in improved signal strength at low pumping power. Because of the relatively long wavelength of the excitation source (798 nm from a mode‐locked Ti:Sap‐phire laser), this technique shows a larger penetration depth into the samples than provided by conventional single‐photon fluorescence confocal microscopy. Single‐photon and two‐photon images of the same area of each sample show significant differences. The results suggest the possibility of using two‐photon confocal microscopy, in conjunction with highly efficient fluorophores, as a tool to study the surface, interface, and fracture in material science applications.
High‐Resolution Lithography with Near‐Field Optical Microscopy
Authors: Naber A. , Kock H. , Fuchs H. 
Published: June 2010

AbstractScanning near‐field optical microscopy (SNOM) is used for lithography to avoid the resolution limiting diffraction of conventional optical methods. We have expanded a commercial SNOM for writing even complex structures on the nanometer scale. Scanning near‐field optical lithography (SNOL) has been applied to conventional resists to explore its potential and the possible combination with conventional optical lithography (mix and match technique).
Ultrastructure of Tracheal Surface Liquid: Low‐Temperature Scanning Electron Microscopy
Authors: Wu D. X‐Y. , Lee C. Y. C. , Widdicombe J. H. , Bastacky J. 
Published: June 2010

AbstractA layer of liquid lines the airways in the lung. Previous microscopic studies have suggested that it is in two phases, with a mucous gel lying above a periciliary sol. However, shrinkage artifacts due to chemical fixation, dehydration, and drying have prevented reliable estimates of the depth of these layers. To avoid such problems, we have studied the surface liquid of bovine trachea by low‐temperature scanning electron microscopy (LTSEM). A polished copper probe cooled to liquid nitrogen temperature was applied to the mucosal surface of sheets of excised tracheal epithelium to effect rapid freezing of surface liquid. Tissue sheets were then mounted in an LTSEM (AMRay 1000A with Biochamber) which maintains samples at ‐180°C with a Joule‐Thompson refrigerator built into the stage. Tissues were fractured at right angles to the epithelial surface, coated with gold, and viewed, all at 10−5 to 10−6 torr without transfer through air. The sample was stable under the electron beam at accelerating voltages up to 20 kV. Epithelial features (nuclei, cilia, microvilli, mucous granules) were well preserved. The mucosal surface of the cells was covered with material on the order of 8 μm in depth. The mucous gel and periciliary sol could be seen as distinct layers and could be distinguished by the size and pattern of ice crystal voids generated by radiant‐etching of the fractured surface of the sample.
CASINO: A new monte carlo code in C language for electron beam interaction —part I: Description of the program
Authors: Hovington Pierre , Drouin Dominique , Gauvin Raynald 
Published: June 2010

AbstractThis paper is a guide to the ANSI standard C code of CASINO program which is a single scattering Monte CArlo SImulation of electroN trajectory in sOlid specially designed for low‐beam interaction in a bulk and thin foil. CASINO can be used either on a DOS‐based PC or on a UNIX‐based workstation. This program uses tabulated Mott elastic cross sections and experimentally determined stopping powers. Function pointers are used for the most essential routine so that different physical models can easily be implemented. CASINO can be used to generate all of the recorded signals (x‐rays, secondary, and backscattered) in a scanning electron microscope either as a point analysis, as a linescan, or as an image format, for all the accelerated voltages (0.1–30 kV). As an example of application, it was found that a 20 nm Guinier‐Preston Mg2Si in a light aluminum matrix can, theoretically, be imaged with a microchannel backscattered detector at 5 keV with a beam spot size of 5 nm.
Real‐time white light reflection confocal microscopy using a fibre‐optic bundle
Authors: Juškattis R. , Wilson T. , Watson T. F. 
Published: June 2010

AbstractWe describe a real‐time white light reflection con‐focal microscope incorporating an optical fibre bundle and characterise the optical performance of the bundle. The use of an incoherent light source enables us, for the first time, to present speckle‐free endoscopic reflected light confocal images. The system has potential application for in vivo studies.
CASINO: A new monte Carlo code in C language for electron beam interactions—part III: Stopping power at low energies
Authors: Hovington Pierre , Drouin Dominique , Gauvin Raynald , Joy David C. , Evans Neal 
Published: June 2010

AbstractThis paper is a description of the stopping power routine utilized in the CASINO program that is based on the experimental measurement of the energy loss function (ELF). In addition, we present an ANSI C standard program that can be used to generate the data needed for the stopping power routine. Both optical and energy loss spectrum (ELS) measurements of the ELF can be used as input to compute the stopping power. For ELS, only the single scattering spectrum is needed. Hence, measurement of the stopping power for a given element or compound of interest can easily be performed and used in the CASINO program. The resulting effect of using these stopping powers in Monte Carlo simulations is generally to increase the backscattering coefficient. Except for carbon, the change of stopping power for pure elements so far compiled is relatively small. In some compounds (i.e., Al2O3 and ZnSe), the discrepancy with the Joy and Luo (1989) expression is significant.
Assessment and correction of geometric distortions in low‐magnification scanning electron microscopy images
Authors: Marschallinger Robert , Topa Dan 
Published: June 2010

AbstractA method is introduced to assess and correct the geometric distortions which frequently occur in low‐magnification scanning electron microscopy (SEM) images. Such images typically exhibit a complex pattern of varying deviations from orthogonality which cannot be adequately corrected by simple geometric transformations such as shifting, scaling, rotation, or shearing. A suitable approach to rectify low‐magnification SEM images is polynomial warping, a correction procedure which also accomplishes rubber sheet transformation. To demonstrate the approach, a reference grid for low magnifications has been scanned at 40‐ and 55‐fold magnifications by means of a microanalyzer. Calculated geometric distortions range from 1.5 to 3.5% of the image dimensions; applying polynomial warping, distortions could be reduced to approximately 0.1% of the image dimensions. Because of its easy application and the widespread availability in image processing packages, polynomial warping can be recommended as a routine procedure for rectifying low‐magnification SEM images.
Chicken erythrocyte nucleosomes have a defined orientation along the linker DNA—A scanning force microscopy study
Authors: Fritzsche Wolfgang , Henderson Eric 
Published: June 2010

AbstractThe orientation of nucleosomes was investigated using scanning force microscopy (SFM) of hypotonically spread chicken chromatin. A virtual cross section parallel to the substrate at half maximum height of the nucleosomal structure revealed an elliptical shape. The orientation of the major axis of this ellipse was investigated in reference to the direction of the axis of the nucleosomal chain. An alignment of the nucleosomes along the nucleosomal chain was observed, with more than 50% of the nucleosomes aligned with the long axis of the chain within ≤ 30° deviation. The alignment distribution peaked at 10–20°. The application of SFM‐based image processing for the structural investigation of a protein‐DNA complex demonstrates the potential for this approach in structural molecular biology.
Environmental scanning electron microscopy investigations of biodeterioration
Authors: Ray Richard , Little Brenda , Wagner Patricia , Hart Kevin 
Published: June 2010

AbstractCase studies will be presented in which environmental scanning electron microscopy (ESEM) has been used to provide unique insight into the role of microorganisms in deterioration processes. ESEM is an excellent tool for demonstrating spatial relationships between microorganisms and substrata because hydrated, nonconducting samples can be viewed with a minimum of manipulation. Copper and iron‐rich deposits associated with bacteria were detected within corrosion layers on copper and steel surfaces, respectively. Fungal mycelia growing on wooden storage spools were shown to penetrate protective grease on carbon steel wire rope in contact with the spool and to cause localized corrosion. Large numbers of marine bacteria were documented within paint blisters and disbonded regions of fiber‐reinforced polymeric composites. In both cases, it appears that microbial gas production resulted in mechanical damage to the substrata.
Characterization of polyox ® granules using environmental scanning electron microscopy
Authors: Roberts R. A. , Shukla A. J. , Rice T. 
Published: June 2010

AbstractThe scanning electron microscope (SEM) has been frequently used in the pharmaceutical industry for studying pharmaceutical products. However, the technique does not allow for the continuous characterization of a product in both dry and hydrated states without processing the product. Through the recent advent of the environmental scanning electron microscope (ESEM), it is now possible to observe a sample in both the dry and hydrated states without extensive product preparation. The ESEM also allows for continual observation during the hydration process from the dry state until the sample is dissolved. In this study, the ESEM was used to characterize the morphologic differences and hydration patterns of granules formulated with a water‐soluble hydrophilic swelling polymer, Polyoxy. Two molecular weights (1, 000, 000 and 7, 000, 000) of the polymer were used in concentrations ranging from 10 to 25% w/w. Visual differences in granule surface morphology and differences in hydration patterns were seen in granules prepared from different polymer concentrations. The morphologic data were corroborated by surface area measurements taken on a surface area analyzer. The rate at which the granule dissolved in the ESEM also correlated with the drug dissolution times determined by the standard USP dissolution method.
A fast and versatile scan unit for scanning probe microscopy
Authors: Knebel D. , Amrein M. , Voigt K. , Reichelt R. 
Published: June 2010

AbstractIn scanning probe microscopy (SPM), the image acquisition time is usually very long because of the limited speed with which the scanning device can trace the topography of the specimen under feed‐back control. This limitation is often brought about by the natural frequency of the scanner in the direction perpendicular to the sample plane that confines the usable bandwidth of the feed‐back loop. In this paper, we present a piezo‐ceramic scanner that provides a large scan range and at the same time allows for adjustment of the probe‐to‐sample distance faster by about one order of a magnitude than a conventional setup. This is achieved through the combination of a large single tube scanner that provides a high‐scan range and a small piezo element for swift motion in the direction perpendicular to the sample plane. The natural frequency in this direction lies at about 275 kHz. We outline the design considerations to avoid disturbing excitation of the scanner through the fast piezo element.