bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling precipitation in frontal rainbands
Authors: Cox G. P.
Published: June 2010

The main aim of this study is to establish the ability of a simple parametrization to represent adequately the microphysical processes acting in frontal rainbands. In order to do this we compare it with a more detailed parametrization in conditions typical of warm frontal and narrow cold frontal rainbands. Simulations using a 2‐dimensional diagnostic model indicate that a mixed phase parametrization is required in dynamical models of high resolution.
The adjustment of numerical weather prediction models to local perturbations
Authors: Barwell B. R. , Bromley R. A.
Published: June 2010

The linearized two‐dimensional equations of motion of an f plane are solved for a localized perturbation using local polar coordinates, and a general solution involving Bessel functions is found which can be fitted to any initial conditions. Three types of perturbation are used as examples; they show the formation of an external gravity wave which propagates outward leaving a geostrophically balanced residual flow as t→x. The divergent component of the initial wind field has no effect on this residual flow. Experiments in which the same perturbations were applied to all levels of a numerical model showed good agreement with the analytical solutions.

Using an isentropic temperature profile as an example, the theory is extended to three‐dimensional perturbations. As well as the gravity waves and geostrophic residual flow found in two dimensions, a third component of the solution is found, namely, an inertial oscillation originating in the deviation of the wind perturbation from its vertical mean. This oscillation continues indefinitely with the Coriolis frequency. Numerical model experiments show good agreement with the solutions in the early stages of adjustment though the inertial oscillation slowly decays through internal gravity wave generation.

Finally, the analytical solutions are discussed in the light of the results of research on the design and performance of analysis schemes.
Medium and extended range predictability and stability of the Pacific/North American mode
Authors: Palmer T. N.
Published: June 2010

It is shown from an assessment of a small set of extended range forecasts from two centres, and from a much larger set of medium range forecasts from one centre, that variability in predictive skill is strongly related to fluctuations in the Pacific/North American (PNA) mode of low frequency variability. A hypothesis is put forward that this is associated with the dependence of large‐scale instability of the forecast flow on the amplitude of the PNA mode. The hypothesis is tested in a barotropic model using as basic states, composite skilful and unskilful cases from the set of medium range forecasts and individual monthly mean fields. Results from the barotropic stability analysis suggests possible reasons for the asymmetric nature of the response of general circulation models to sea surface temperature anomalies of opposite sign, relevant to forecasting on monthly to seasonal timescales. Observational evidence for the stability hypothesis is also discussed.
Air parcel thermodynamic properties and aerosol particle concentrations in the maritime atmospheric boundary layer
Authors: Smith M. H.
Published: June 2010

In some circumstances, the distribution of particles in the maritime atmosphere may be simply related to the atmospheric profile. For data obtained in the Outer Hebrides in 1982 by the Meteorological Office Research Flight aircraft, a strong correlation is found between particle concentrations over the radius range from 0.25 to 4m̈m and the thermodynamic properties of air parcels at various levels within the marine atmospheric boundary layer. This approach offers a potential tool toward better understanding of particle distribution and provides a means for estimating particle concentrations at various levels on the basis of a standard meteorological sounding.
Digital imaging for scanning electron microscopy
Authors: Postek Michael T. , Vladár András E.
Published: June 2010

The development and application of digital imaging technology has been one of the major advancements in scanning electron microscopy (SEM) during the past several years. This digital revolution has been brought about by significant progress in semiconductor technology, notably the availability of less expensive, high‐density memory chips and the development of inexpensive, high‐speed, analog‐to‐digital and digital‐to‐analog converters, mass storage, and high‐performance central processing units. This paper reviews a number of the advantages presented by digital imaging as applied to the SEM and describes a system developed at the National Institute of Standards and Technology for this purpose.
A fast‐scanning optical microscope for imaging magnetic domain structures
Authors: Ping G. L. , See C. W. , Somekh M. G. , Suddendorf M. B. , Vincent J. H. , Footner P. K.
Published: June 2010

This paper describes a fast‐scanning Kerr microscope which produces quantitative and repeatable images with a scan rate of one frame/s. The rapid scan facility results in a practical system for routine examination of magnetic samples, whereas presently available scanning and full‐field systems are relatively slow.
Design and characterisation of a single‐reflection, solid‐state detector with high discrimination against backscattered electrons for cathodoluminescence microscopy
Authors: Pey K. L. , Phang J. C. H. , Chan D. S. H. , Leong Y. K.
Published: June 2010

Aportable solid‐state detector (SSD) for cathodoluminescence (CL) has been constructed and tested. The detector geometry utilises a parabolic reflector to direct light towards the solid‐state detection element. The photo‐sensitive area of the solid‐state photodiodes is situated at a level in line with or sightly below the top surface of the specimen to minimise the collection of backscattered electrons (BSEs) coming directly from the beam impact point. The components have been integrated into a single unit to enhance portability. In comparison with a commercial CL detection system, the new geometry shows excellent efficiency in rejecting BSE contribution during CL operation. A light collection solid angle close to 1.97π steradian is realised in this geometry, higher than other SSD‐CL systems. A method for characterising CL detection system performance has been developed.
A Monte Carlo modeling of electron interaction with solids including cascade secondary electron production
Authors: Ding Z.‐J. , Shimizu R.
Published: June 2010

A new Monte Carlo simulation approach has been developed to describe electron scattering and secondary electron generation processes in solids. This approach is based on the uses of Mott's elastic scattering cross section and Penn's dielectric function. A very good agreement has been found on the energy distribution of backscattered electrons between theoretical calculations and accurate experimental measurement recently made by Goto et al. (1994). This fact confirms that the present Monte Carlo model is very useful for more comprehensive understanding of basic phenomena in electron spec‐troscopy and microscopy, particularly in the sub‐keV energy region where cascade secondary electrons play a dominant role. In this paper the details of the Monte Carlo procedure are described and further application to the mechanism of secondary electron generation is presented.
A portable scanning electron microscope column design based on the use of permanent magnets
Authors: Khursheed A. , Phang J. C. , Thong J. T. L.
Published: June 2010

A portable scanning electron microscope (SEM) column design is presented which makes use of permanent magnets. Simulation results predict that such an SEM column is feasible and that it can be compact. The column height is typically less than 12 cm. The column is designed to be modular, so that it can fit onto a wide range of different specimen chamber types, and can also be readily replaced.
Monte Carlo modeling of cathodoluminescence generation using electron energy loss curves
Authors: Toth M. , Phillips M. R.
Published: June 2010

This work demonstrates the validity of approximating cathodoluminescence generation throughout the electron interaction volume by the total electron energy loss profile. The energy loss profiles in multilayer specimens were accurately calculated using the Monte Carlo simulation CASINO. Resolution of cathodoluminescence images can be estimated from the electron beam spot diameter, the electron penetration range, and the minority carrier diffusion length.
Scanning near‐field cathodoluminescence investigations
Authors: Cramer R. M. , Heiderhoff R. , Balk L. J.
Published: June 2010

By implementing a scanning near‐field optical microscope into the analysis chamber of a scanning electron microscope, the light emitted due to cathodoluminescence can be locally detected in the near‐field using tapered, coated optical fibers. In addition to the ability to perform contactless measurements of local diffusion lengths, the achievable spatial resolution can be increased to about 50 nanometers.
The morphology and composition of cholesterol, protein, and bilirubin deposits in dried human bile: Cathodoluminescence and backscattered electron imaging
Authors: Loginov A. S. , Chebanov S. M. , Saparin G. V. , Obyden S. K.
Published: June 2010

This work is the first to deal with the application of color cathodoluminescence scanning electron microscopy (CCL SEM) and a novel version of combined imaging with backscattered electrons (CCL+BSE SEM) for the study of the composition of bile and its precipitation mechanisms. The present study demonstrates cholesterol, protein, and bilirubin distribution in deposits of normal and abnormal humanbile after solution evaporation to full dryness. Qualitative CCL SEM analysis showed that dried bile remnants include different proportions of the above components. Three types of deposits were observed: Arborescent crystals, typical cholesterol crystals, and amorphous bilirubin particles. The selection of crystalline or amorphous precipitate phases is determined by the dehydration/concentration process. The findings may explain key features in lithogenesis.
Wide field scanning slit in vivo confocal microscopy of flattening‐induced corneal bands and ridges
Authors: Auran James D. , Koester Charles J. , Rapaport Rachel , Florakis George J.
Published: June 2010

We used a wide field scanning slit confocal microscope to examine the response of the in vivo human cornea to flattening. Flattening‐induced effects consisted of (1) anterior corneal mosaic, which appeared as a meshwork of intersecting stromal and Bowman's layer bands with overlying epithelial ridges; (2) deep and middle stromal bands, which were narrower than and unrelated in position to the anterior corneal mosaic; and (3) posterior surface ridges. The posterior surface ridges projected posteriorly into the anterior chamber consisted of endothelium, Descemet's membrane, and posterior stroma, and were unrelated in position to posterior stromal bands. Confocal microscopy is a promising modality in the examination of the cornea and its response to mechanical stress.
The intracellular distribution of vinculin and alpha2 integrin in epithelial cells and chondrocytes
Authors: Hirsch M. S. , Law L. Y. , Trinkaus‐Randall V. , Svoboda K. K. H.
Published: June 2010

The purpose of this study was to demonstrate the presence of vinculin and alpha2 integrin in chondrocytes in situ and epithelial cells. We also determined that the appropriate fixation and extraction protocols for immunohistochemistry and laser scanning confocal microscopy for an integral membrane protein and an actin‐associated protein in cultured cells and whole tissue was different. Cultured epithelial cells, whole mount human cornea and avian cartilage were fixed and prepared using a number of standard procedures used for indirect fluorescence immunohistochemistry. The distribution of vinculin was cell‐type and fixation‐specific. Chondrocytes and cultured epithelial cells demonstrated vinculin in areas that appear to be associated with filamentous actin. Vinculin was associated with cell membranes in human cornea. The expression of alpha2 integrin observed in chondrocytes fixed with methanol, paraformaldehyde, or formaldehyde is consistent with its role in cell‐substrate interaction, but may also suggest a role in dividing and differentiating cells. The localization of alpha2 integrin in human corneal epithelia supports its role as a cell‐cell adhesion molecule. The cytoplasmic distribution of vinculin and alpha2 integrin in tissues fixed without detergent extraction suggests that the fixation step may be sufficient for antibody penetration and antigen extraction. These studies are the first report of vinculin and alpha2 integrin in embryonic chondrocytes. In addition we have shown that confocal laser scanning microscopy combined with proper fixation and extraction protocols may optimize the localization of antigens in cultured and whole mount cells.
In vivo observation of the corneal epithelium
Authors: Tsubota Kazuo
Published: June 2010

Specular microscopy is an important addition to the ophthalmologist's diagnostic armamentarium. Using this technique, it has been found that normal corneal epithelial cells are polygonal, with no abnormal specular reflex. There are no spindle‐shaped, large or small cells, as may be observed in a variety of pathologic conditions. Spindle‐shaped cells are characteristic of the wound‐healing process with cell migration. Large cells were observed not only in wound healing, but also in aphakic diabetic patients, extended‐wear soft contact lens wearers, and individuals with keratoconus. These changes may result from depressed mitosis or inhibited sloughing of superficial cells. Morphometric analysis adds a quantitative dimension to epithelial cell analysis.
In vivo observation of the human tear film by tandem scanning confocal microscopy
Authors: Mathers William D. , Daley Thomas E.
Published: June 2010

A new method for observing normal and pathologic states of the human tear film using tandem scanning confocal microscopy is presented. The confocal microscope is configured with a horizontal light path, a 10 × dry objective, and an image‐intensified camera for collecting images at a magnification of approximately 150×. The advantages of confocal microscopy can be used to collect reflected images of the human tear film with improved detail and resolution.
Near fields of periodic gratings calculated using rigorous electromagnetic theory
Authors: Körner T. O. , Sheridan J. T.
Published: June 2010

Rigorous electromagnetic theory (REMT) can be used to calculate the fields above dielectric and metallic gratings. In this paper, by including evanescent orders, the near fields are presented. The Legendre method is used to carry out these calculations. In this method the fields in each of the homogeneous sections along a grating period are approximated by Legendre polynomials. This method is an exact eigenfunction method in which the eigenvalues are found using simple matrix eigenvalue/eigenvector algorithms. By carefully dealing with the boundary conditions, extremely deep and highly conducting gratings can be examined. The convergence of the diffraction orders and nonimplicit power conservation are used to test the results. Contour plots showing the absolute value of the E‐field near gratings for a large range of periods, depths, duty cycles, angles of incidence, and surface profiles are presented.
A formula to explain electron backscattering in solids
Authors: Gauvin Raynald , Joy David C. , Hovington Pierre
Published: June 2010

This note generalizes the Archard model for electron backscattering. It is shown that the energy‐dependent variation of electron backscattering can be predicted.
Vital confocal microscopy in bone
Authors: Boyde A. , Wolfe L. A. , Maly M. , Jones S. J.
Published: June 2010

We wished to exploit confocal microscopy for high spatial and temporal resolution vital microscopy in bone. To this end, we evolved implants with glass windows supported in titanium, which were placed in the medial proximal tibial plateau of the rabbit, and special small, self‐focussing objectives (dry 10/0.25, water immersion 20/0.45, and oil immersion 45/0.65 and 120/1.0) which mated and matched to the conical window entrance section of the metal components. At intervals of up to 21 months after implant healing, these lenses were used to study live tissue using two genera of confocal microscope: multiple aperture disc, tandem scanning, microscopes for observation in reflection, and video rate confocal laser scanning microscopes for recording, mainly in the fluorescence mode. The latter allowed the study of a variety of intravenously administered substances, including fluorescein, fluorescein‐dextrans, fluorescent microspheres, acridine orange, DASPMI, calcein, and tetracycline. We were able to remove blood, stain cells with fluorescent markers, and replace them into the circulation. Calcein and tetracycline bind to the mineral front in bone: this labelling was studied in progress. We observed that both substances partition and remain for long periods (at least days) in adipocytes. Further characterisation of the system used both confocal fluorescence and scanning electron microscopy methods in the study of retrieved implants. These studies showed that the subimplant cortical bone remodelled to a less compact structure with a rich microvasculature extremely close to bone. The points of attachment of bone to glass were found to involve coarse fibres, with the matrix containing large numbers of large cells: some of this tissue was cartilage and some immature bone. An amorphous, mineralised matrix was in immediate contact with glass. The results provide further confirmation of the general utility of high‐scan speed confocal methodology in physiology.
Calibration and applications of a high‐precision piezo scanner for nanometrology
Authors: Dürselen R. , Grunewald U. , Preuss W.
Published: June 2010

Piezoelectric tube scanners are being used with many scanning probe microscopes for scanning sample surfaces in three dimensions. Since the piezo effect has nonlinearity, hysteresis, and drift, difficulties will occur with distortion, reproducibility, and accuracy of measurements (Barrett and Quate 1991). Correction procedures, which are not based on improvement of linearity of scan movements, will still be affected by remaining nonlinearities of an order of a few percent. The manufacturing of increasing amounts of miniaturized structures for microsystems and semiconductors, as well as certification of standards and measuring devices, will, however, require higher accuracy of profile measurements in the submicrometer and nanometer range. This publication describes a scanner which has a nonlinearity of < 0.05%, a procedure for calibration and detection of nonlinearity, as well as some applications. The calibration technique is based on the fact that manufacturing and measurement of optical diffraction gratings can be very well controlled, allowing light wavelength as an indirect reference in the nanometer range (Antrak 1993, Bartzke et al. 1993, Grunewald 1993, Hutley 1982).
Influence of the angular distribution of backscattered electrons on signals at different take‐off angles in low‐voltage scanning electron microscopy (LVSEM)
Authors: Spranck M. , Kässens M. , Reimer L.
Published: June 2010

It is well known that the differential Mott cross section for large‐angle elastic scattering shows maxima and minima at angles depending on material and electron energy. For electron energies of 10–30 keV, the averaging by frequent elastic scattering processes results in approximate Lambert angular distributions of backscattered electrons (BSE). However, the present Monte Carlo calculations for electron energies E = 1–5 keV and different angles of incidence show strong deviations from a Lambert distribution which increases with decreasing energy. The signals of the BSE detector with five annular segments for different take‐off directions show good agreement with the calculations for normal electron incidence.
Cathodoluminescence imaging—the study of yttrium aluminates distribution in aluminum nitride
Authors: Wang Frank Cheng‐Yu
Published: June 2010

Cathodoluminescence imaging is a technique which may combine a high‐resolution spectroscopic method with a high‐spatial resolution electron imaging technique to characterize chemical identity as well as physical size, shape, and spatial distribution of the materials which have cathodoluminescence. Cathodoluminescence imaging has been used to characterize yttrium aluminates in aluminum nitride ceramics. By digitally combining cathodoluminescence and backscat‐tering electron images, it is possible not only to distinguish between different yttrium aluminates, but also to determine the size, shape, and spatial distribution of these phases. This information provides a route to understanding the local residual oxygen concentration before sintering, the amount of sintering aid to be added, and possible sintering schedule. Furthermore, this information may be related to other properties of aluminum nitride such as residual oxygen concentration and thermal conductivity.
Combined atomic force and scanning reflection interference contrast microscopy
Authors: Hillner P. E. , Radmacher M. , Hansma P. K.
Published: June 2010

A sphere attached to a cantilever is used simultaneously as an atomic force microscope (AFM) tip and as a curved reflective surface for producing scanning reflection interference contrast microscope (RICM) images of fluorescent beads dried onto a glass slide. The AFM and RICM images are acquired in direct registration which enables the identification of individually excited beads in the AFM images. The addition of a sharp, electron beam‐deposited tip to the sphere gives nanometer resolution AFM images without loss of optical contrast.
Image compression and data integrity in confocal microscopy
Authors: Avinash Gopal B.
Published: June 2010

To manage large volumes of image data generated routinely using real‐time confocal microscopy, compressing image data using a lossy algorithm prior to sustained video rate transferring and/or storing is proposed. Test criteria for determining the acceptability of uncompressed data, both qualitatively and quantitatively, are described, and an empirical demonstration of the use of lossy compression in data management is provided. It is found that, if appropriately used, the lossy compression scheme could retain all the useful information in the data while providing better compression ratios (memory for the original/ memory for the compressed) when compared with a lossless scheme.
Frictional effects in atomic force microscopy of Langmuir‐Blodgett films
Authors: ten Grotenhuis E. , van Milterburg J. C. , van der Eerden J. P.
Published: June 2010

Frictional effects in atomic force microscopy (AFM) of Langmuir‐Blodgett films of 1, 2‐dipalmitoyl‐snglycero‐phosphoglycerol were examined. Height measurements of the Langmuir layers are strongly influenced by the orientation of the cantilevers used in AFM relative to the sample. A simple model is used to describe the frictional effects and to calculate the real height of the monolayers.
Chemical etching of natural fluorapatite crystals in acid solutions studied with the scanning electron microscope
Authors: Dorozhkin Sergey V.
Published: June 2010

Different aspects of the chemical etching process for natural fluorapatite (FAP) crystals in pure phosphoric acid solutions and for those with additives of Ca2+ and H2SO4 have been studied by means of the scanning electron microscope. The resulting experimental data obtained in the etching process are very sensitive to dissolving conditions, type of crystal face, and the presence or absence of any epitaxial coatings on the surface of dissolving crystals. It was found that the pyramidal crystal faces of the FAP have the highest dissolution rate value and, as a result, are not etched at all. The prism and pinacoid faces usually are covered by hexagonal etch pits under the same conditions. Additives of Ca2+ to the phosphoric acid solution result in transition from a chemical etching to a chemical polishing process, and additives of H2SO4 result in epitaxial coatings of CaSO4· xH2O (x = 0,0.5, 2) and shapeless pits formation.
A study of the kinetics of topochemical reactions by scanning electron microscopy
Authors: Melikhov I. V. , Nikolaev A. L. , Bozhevolnov V. E. , Ivanov L. N. , Kozlovskaya E. D. , Saparin G. V.
Published: June 2010

Based on the data of fluorapatite interaction with tartaric and sulfuric acids, a scheme is developed for establishing the function of states distribution for product particles by means of scanning electron microscopy (SEM). The result of the studies confirms the availability of a quantitative description of topochemical reactions kinetics using SEM data in the terms presented by diagnostic formulae.
Experimental determination of angular‐energy distributions of electrons backscattered by bulk gold and silicon samples
Authors: Gérard P. , Balladore J. L. , Martinez J. P. , Ouabbou A.
Published: June 2010

This work describes an experimental study of the backscattering of electron beams with an energy range between 20 and 100 keV. The energy distribution of electrons backscattered by bulk gold and silicon samples at different take‐off angles was determined with an original device. The different major sources of noise were studied and then the spectra obtained were processed. Theoretical interpretation of this phenomenon using Monte Carlo simulations will be presented in a future paper.
An improved cone‐beam reconstruction algorithm for the circular orbit
Authors: Hu Hui
Published: June 2010

By reformulating Grangeat's algorithm for the circular orbit, it is discovered that an arbitrary function to be reconstructed, f(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}), can be expressed as the sum of three terms:f(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document})=fMO(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document})+fMI(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document})+f N(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) wherefMO(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) corresponds to the Feldkamp reconstruction,fMI(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) represents the information derivable from the circular scan but not utilized in Feldkamp's algorithm, andfN(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) represents the information which cannot be derived from the circular scanning geometry. Thus, a new cone‐beam reconstruction algorithm for the circular orbit is proposed as follows: (1) compute fMO(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) using Feldkamp's algorithm, (2) compute fMI(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) using the formula developed in this paper, and (3) estimatefN(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) using a priori knowledge such as that suggested in Grangeat's algorithm. This study shows that by including the fMI(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) term, the new algorithm provides more accurate reconstructions than those of Feldkamp even without thefN(\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop r\limits^ \to $\end{document}) estimation.
Color cathodoluminescence study of oxides subjected to thermal environments
Authors: Nazarova T. A. , Saparin G. V. , Obyden S. K. , Ivannikov P. I.
Published: June 2010

The behavior of cathodoluminescence (CL) from oxides associated with plastic deformation as well as with annealing at different temperatures and atmospheres has been examined. Observations using the real color CL (CCL) mode in a scanning electron microscope show that the annealing temperature rather than the annealing atmosphere is the major factor influencing the observed changes in the spatial distribution of the total CL emission from the microdeformed surface. However, at the same annealing temperature, the spectral composition of the CL depends on the annealing atmosphere. An attempt has been made to explain the obtained results in terms of defect theory and radiation effects in electron microscopy.
The effect of some instrument operating conditions on the x‐ray microanalysis of particles in the environmental scanning electron microscope
Authors: Carlton Robert A.
Published: June 2010

The objective of this investigation was to evaluate the practical effects of electron beam broadening in the environmental scanning electron microscope (ESEM) on particle x‐ray microanalysis and to determine some of the optimum operating conditions for this type of analysis. Four sets of experiments were conducted using a Faraday cage and particles of copper, glass, cassiterite, andrutile. The accelerating voltage and chamber pressure varied from 20 to 10 kV and from 665–66 Pa (5.0 to 0.5 torr), respectively. The standard gaseous secondary electron detectors (GSED) and the long environmental secondary dectectors (ESD) for the ESEM were evaluated at different working distances. The effect of these parameters on the presence of artifact peaks was evaluated. The particles were mounted on carbon tape on an aluminum specimen mount and were analyzed individually and as a mixture. Substrate peaks were present in almost all of the spectra. The presence of neighboring particle peaks and the number of counts in these depended upon the operating conditions. In general, few of these peaks were observed with the long ESD detector at 19 mm working distance and at low chamber pressures. More peaks and counts were observed with a deviation from these conditions. The most neighboring peaks and counts were obtained with the GSED detector at 21.5 mm working distance, 10 kV accelerating voltage, and 665 Pa (5.0 torr) chamber pressure. The results of these experiments support the idea that the optimum instrumental operating conditions for EDS analysis in the ESEM occur by minimizing the gas path length and the chamber water vapor pressure, and by maximizing the accelerating voltage. The results suggest that the analyst can expect x‐ray counts from the mounting materials. These tests strongly support the recommendation of the manufacturer to use the long ESD detector and a 19 mm working distance for EDS analysis. The results of these experiments indicate that neighboring particles millimeters from the target may contribute x‐ray counts to the spectrum.
Environmental scanning electron microscopy studies of diffusion mechanism of boron particle combustion
Authors: Yeh C. L. , Kuo K. K. , Klimkiewicz M. , Brown P. W.
Published: June 2010

This investigation was performed to resolve long‐term contradicting theories regarding the mechanisms which govern the species diffusion across the liquid B2O3 layer covering a single boron particle during the combustion of boron. An environmental scanning electron microscope (ElectroScan E‐3) was used to observe the liquefaction characteristics of the boron oxide layer and to examine boron dissolution and species diffusion processes in real time. Using a hot stage, crystalline boron particles were heated from 25 to 950°C in O2, H2O, or Ar environments. Pure B2O3 particles were also heated in an O2 environment and examined. In situ observations showed that the diffusion of dissolved boron into molten B2O3(1) is much more dominant at elevated temperatures than the diffusion of gaseous O2 through the B2O3(1) layer. Dissolution of solid boron into the boron oxide layer caused the liquefaction of boron particles at relatively low temperatures (940°C). The chemical composition of liquid boron oxide, coated on the surface of boron particles, was identified as a polymeric vitreous (BO)n complex through the reaction between dissolved boron and molten B2O3(1).
In situ laser heating in an environmental scanning electron microscope
Authors: Foitzik Andreas H. , Füting Manfred W. , Hillrichs Georg , Herbst Ludolf‐Johannes
Published: June 2010

The environmental scanning electron microscope (ESEM) offers improved capabilities for coupling a scanning electron microscope (SEM) with an in situ laser device compared with conventional SEMs. Such coupling generally enables, for example, the observation of laser glazing effects or high‐temperature behaviour as well as thermal shock behaviour of materials and devices. In an ESEM, decomposition caused by high‐temperature gas reactions can additionally be studied while monitoring the gaseous environment online with a mass spectrometer attached to the specimen chamber. In this work, we demonstrate the capabilities of an in situ laser system suitable for heating specimen in an in situ deformation stage, thus enabling the further study of the mechanical properties of materials far beyond temperatures accomplished by thermal heating stages.
Better visualization inside the environmental scanning electron microscope through the infrared chamberscope coupled with a mirror
Authors: Wight Scott A.
Published: June 2010

Clearances are tight inside the specimen chamber of the environmental scanning electron microscope (ESEM), and it is difficult to see the relative positions of detectors and specimens through the viewport. For example, the relative placement of the energy‐dispersive spectrometer (EDS) and the specimen is critical for attaining reasonable x‐ray efficiency while protecting the detector window from damage. An infrared chamberscope and mirror attachment were added to improve the visibility inside the chamber.
High‐speed operation of scanning electron microscope lenses
Authors: Thong J. T. L. , Li F.
Published: June 2010

The speed at which the focal properties of an iron‐shrouded magnetic electron lens can be changed is fundamentally limited by Eddy currents in the magnetic material. The effects of such Eddy currents on the lens properties can be partially compensated by modifying the lens excitation to speed up the lens response. This work considers the application of excitation pre‐emphasis techniques to scanning electron microscope lenses for small and large dynamic changes in excitation. Where transient material saturation effects come into play, attempts to further improve the lens response beyond that at the onset of saturation are futile. Under such circumstances, the use of a closed‐loop feedback arrangement is proposed that can provide a degree of response improvement.
Contact angle of water on paper components: Sessile drops versus environmental scanning electron microscope measurements
Authors: Liukkonen Annukka
Published: June 2010

The wetting properties of paper components and sizing agents were investigated by measuring contact angles of water drops applied by the drop test method on the sample surfaces, and by observing microscopic drops in the environmental scanning electron microscope (ESEM). The results are comparable, although measurements from the ESEM observations are approximate. The ESEM observations give insight into the wetting at the microscopic level, the formation of drops, and the spreading and absorption of water drops. Absorbent samples engulf all condensing water, resulting in a water‐ saturated swollen structure with no visible drop formation. On the nonabsorbent samples, water drops form and spread on the sample surfaces.
Objective comparison of scanning ion and scanning electron microscope images
Authors: Ishitani Tohru , Tsuboi Hideki
Published: June 2010

Common and different aspects of scanning electron microscope (SEM) and scanning ion microscope (SIM) images are discussed from a viewpoint of interaction between ion or electron beams and specimens. The SIM images [mostly using 30 keV Ga focused ion beam (FIB)] are sensitive to the sample surface as well as to low‐voltage SEM images. Reasons for the SIM images as follows: (1) no backscattered‐electron excitation; (2) low yields of backscattered ions; and (3) short ion ranges of 20–40nm, being of the same order of escape depth of secondary electrons (SE) [=(3–5) times the SE mean free path]. Beam charging, channeling, contamination, and surface sputtering are also commented upon.
Theoretical explanation of the relationship between backscattered electron and x‐ray linear attenuation coefficients in calcified tissues
Authors: Wong Ferranti S. L. , Elliott James C.
Published: June 2010

X‐ray absorption and backscattered electron (BSE) microscopies are two commonly used techniques for estimating mineral contents in calcified tissues. The resolution in BSE images is usually higher than in x‐ray images, but due to the previous lack of good standards to quantify the grey levels in BSE images of bones and teeth, x‐ray microtomog‐raphy (XMT) images of the same specimens have been used for calibration. However, the physics of these two techniques is different: for a specimen with a given composition, the x‐ray linear attenuation coefficient is proportional to density, but there is no such relation with the BSE coefficient. To understand the reason that this calibration appears to be valid, the behaviour of simulated bone samples was investigated. In this, the bone samples were modelled as having three phases: hydroxyapatite (Ca10(PO4)6(OH)2), protein, and void (either empty or completely filled with polymethylmethacrylate (PMMA), a resin which is usually used for embedding bones and teeth in microscopic studies). The x‐ray linear attenuation coefficients (calculated using published data) and the BSE coefficients (calculated using Monte Carlo simulation) were compared for samples of various phase proportions. It was found that the BSE coefficient correlated only with the x‐ray attenuation coefficient for samples with PMMA infiltration. This was attributed to the properties of PMMA (density and mean atomic number) being very similar to those of the protein; therefore, the sample behaves like a two‐phase system which allows the establishment of a monotonic relation between density and BSE coefficient. With the newly developed standards (brominated and iodinated dimethacrylate esters) for BSE microscopy of bone, grey levels can be converted to absolute BSE coefficients by linear interpolation, from which equivalent densities can be determined.
Apoptotic pathways depend on the target enzymatic activity and not on the triggering agent
Authors: Luchetti F. , Mariani A. R. , Columbaro M. , di Baldassarre A. , Cinti C. , Falcieri E.
Published: June 2010

Molt‐4 human leukemia cells were triggered to apoptosis by various agents with different mechanisms of action. Staurosporine, a protein kinase C (PKC) inhibitor; camptothecin, a topoisomerase I blocking drug; and tiazo‐furin, an inhibitor of inosine 5′‐phosphate dehydrogenase (IMPDH), were used. Ultrastructural analysis showed morphologic changes characteristic of apoptosis that were very similar for all three agents. Nevertheless, DNA oligonucleosomic fragmentation was not detectable by agarose gel electrophoresis. However, a genomic DNA cleavage appeared after pulse‐field gel electrophoresis (PFGE) in cells treated with these agents for 24 h. Furthermore, in situ nick translation (NT) showed a finely spotted nuclear labelling in staurosporine‐treated cells and a compact fluorescence after camptothecin incubation. In tiazofurin‐treated cells an intermediate pattern was found. Therefore, apoptotic agents with different mechanisms of action induced the formation of large genomic DNA fragments and very similar ultrastructural changes. Therefore, both phenomena and the closely related apoptosis progression depend on target cell machinery and not on the triggering agent.
Application of the technique of environmental scanning electron microscopy to the paper industry
Authors: Manero J. M. , Masson D. V. , Marsal M. , Planell J. A.
Published: June 2010

The environmental scanning electron microscope was used in conjunction with a heating stage to study in situ the polymerization process in the manufacturing of filter papers for the automotive industry. The images obtained from the video recording were converted into TIFF format with a computer program and were then analyzed using an image analyzer to assess the percentage shrinkage during the cure process. These experiments yield valuable information that is impossible to obtain with other electron microscopy techniques, for example, determining whether the polymer envelops the fibers or not, or whether there is a greater or lesser degree of anchoring between fibers.
Numerical chromosomal abnormalities detected by atomic force microscopy
Authors: Ergün Mehmet Ali , Tan Erdal , Şahin Feride Iffet , Menevşe Adnan
Published: June 2010

The numerical abnormalities of human metaphase chromosomes, fixed according to standard procedures for optical microscopy but not treated for banding, were detected by atomic force microscopy (AFM). High‐resolution AFM imaging of chromosomes in trisomy 13, 21, and Klinefelter syndrome can be compared directly with the traditional optical image. The unbanded metaphase chromosomes, including the extra ones in trisomic patients showed a structural pattern very similar to G‐banding. Comparison of AFM images with light microscopic data allows the identification of specific chromosomes, and images of chromosomes showing numerical and structural abnormalities can then be analysed.
Thickness determination of ultra‐thin films using backscattered electron spectra of a new toroidal electrostatic spectrometer
Authors: Schlichting F. , Berger D. , Niedrig H.
Published: June 2010

Backscattered electron spectroscopy offers detailed information for multilayer and subsurface‐layer materials with distinct Z contrast: It can be used for the validation of Monte Carlo calculations, to obtain depth selective electron microtomographic images, and to determine the thickness of ultra thin films on bulk substrates. In this paper we describe a new energy‐dispersive method for thickness determination of thin films on bulk aluminum using backscattered electron (BSE) spectra obtained by a polar, toroidal, electrostatic spectrometer. After a brief recapitulation of the spectrometer's geometry, the techniques for its energy calibration and the preparation of thin double‐layer films are introduced. Backscattered electron measurements and thickness calibrations for Au and Cu films with thicknesses of 0–200 nm on bulk aluminum will be presented for various primary electron energies.
Evaluation of scanning electron microscopy images of a model dressing using image feature extraction techniques and principal component analysis
Authors: Egelandsdal Bjørg , Christiansen Kirsti F. , Høst Vibeke , Lundby Frank , Wold Jens Petter , Kvaal Knut
Published: June 2010

Twelve dressing systems made by varying protein type, oil level, CaCl2, NaCl, and sucrose, were examined using scanning electron microscopy. Images from the 12 systems were quantitatively analysed using methods of feature extraction. These methods were based on vectorisations of the images followed by principal component analysis on the extracted vectors. These techniques were used to examine the reproducibility of the acquired images as well as to relate the images to rheologic and sensory texture parameters. Two feature extraction methods were used: the angle measure technique (AMT) and the absolute difference method (ABDF). The ABDF method used fewer principal components to extract information from images relevant to the complex modulus/sensory viscosity of the system, but the information seemed equally well preserved by the two‐feature extraction methods. The AMT was more efficient in classifying the images with respect to protein type. A fair correlation between images and complex modulus was obtained (R=0.73). It is suggested that a better correlation might be obtained by adding more systems, increasing the number of areas imaged for each system as well as avoiding systems of low viscosity.
Surface roughness of preparations for backscattered electron‐scanning electron microscopy: The image differences and their monte carlo simulation
Authors: Howell P. G. T. , Boyde A.
Published: June 2010

Patterns and levels of mineralisation in the biological hard tissues have been studied using the backscattered electron (BSE) mode in the scanning electron microscope (SEM). To prevent gross topographic detail overwhelming changes in signal from composition, samples are embedded in polymethylmethacrylate (PMM A) and a flat block surface produced by polishing or micromilling. This study was undertaken to establish the degree of residual topography achieved in these finishing processes. A sample of human rib was embedded in PMMA and prepared, as for examination in the SEM, by polishing on graded abrasives and pre‐ and, finally, ultra‐milling. After each preparation step, the block face was imaged using a confocal reflection microscope surface mapping facility. The recorded topographies were used in a Monte Carlo simulation to model the surface interface and thus, for each of the sample preparation techniques, to calculate predicted variations in BSE signal. The latter were compared with experimental data derived under standard operating conditions in the SEM. Micromilling produced block faces with typical peak‐trough relief of 80 nm, while hand polishing left occasional scratches 1.5 μm deep with a general undulation of 150–250 nm. Monte Carlo simulations of a rough surface of bone using these data predicted that additional contrast levels of 5% could be expected from micromilled surfaces and > 10% for hand polished samples of bone. Thus, micromilling is the best preparation method for bone, since this tissue develops a collagen orientation‐related relief on polishing, which may be largely responsible for the (incorrect) supposition that lamellation in bone is related to changes in net degree of mineralisation.
The mechanism of G‐banding detected by atomic force microscopy
Authors: Şahin Feride Iffet , Ergün Mehmet Ali , Tan Erdal , Menevşe Adnan
Published: June 2010

The morphologic changes occurring in human chromosomes during G‐banding by trypsin treatment on the same metaphase were followed with the aid of an atomic force microscope (AFM). It was found that trypsin treatment alone caused a pattern of collapse in the chromosomes that was clearly dependent on the duration of trypsinization. The progressive pattern of collapse first indicated the loss of internal differentiation between chromatids, then bands, and finally all internal structures, except for edges running around the chromosomes' perimeter. When stained with Giemsa, the collapsed chromosomes partly regained their original form, and transverse ridges appeared that correspond to G‐positive band regions. However, the treatment of fixed chromosomes with trypsin for 42 s diminished the chromosomal edges, and the z‐dimensions could not be measured even with the subsequent application of Giemsa.
Determination of secondary electron spectra from insulators
Authors: Yong Y. C. , Thong J. T. L.
Published: June 2010

A new technique for the determination of secondary electron (SE) spectra of insulators in a scanning electron microscope environment is presented. It is based on a capacitatively coupled charge measurement by subjecting the insulating film to a controlled pulsed electron beam. With the use of a planar grid analyzer configuration, an algorithm is used to estimate the SE spectrum based on normalized values of the S‐curve obtained. Secondary electron spectra from several insulating materials employed in integrated circuit manufacturing, including silicon nitride (Si3N4), AZ 1350J photoresist, and pyralin polyimide, have been measured.