bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer‐based materials to be used as the active element in microsensors: A scanning force microscopy study
Authors: Porter Timothy L. , Eastman Michael P. , Pace Danielle L. , Bradley Michelle 
Published: June 2010

AbstractPolymer‐based materials can be incorporated as the active sensing elements in chemiresistor devices. Most of these devices take advantage of the fact that certain polymers will swell when exposed to gaseous analytes. To measure this response, a conducting material such as carbon black is incorporated within the nonconducting polymer matrix. In response to analytes, polymer swelling results in a measurable change in the conductivity of the polymer/carbon composite material. Arrays of these sensors may be used in conjunction with pattern recognition techniques for purposes of analyte recognition and quantification. We have used the technique of scanning force microscopy (SFM) to investigate microstructural changes in carbon‐polymer composites formed from the polymers poly(isobutylene) (PIB), poly (vinyl alcohol) (PVA), and poly (ethylene‐vinyl acetate) (PEVA) when exposed to the analytes hexane, toluene, water, ethanol, and acetone. Using phase‐contrast imaging (PI), changes in the carbon nanoparticle distribution on the surface of the polymer matrix are measured as the polymers are exposed to the analytes in vapor phase. In some but not all cases, the changes were reversible (at the scale of the SFM measurements) upon removal of the analyte vapor. In this paper, we also describe a new type of microsensor based on piezoresistive microcantilever technology. With these new devices, polymeric volume changes accompanying exposure to analyte vapor are measured directly by a piezoresistive microcantilever in direct contact with the polymer. These devices may offer a number of advantages over standard chemire‐sistor‐based sensors.
Dynamic secondary electron contrast effects in liquid systems studied by environmental scanning electron microscopy
Authors: Stokes D. J. , Thiel B. L. , Donald A. M. 
Published: June 2010

AbstractWe report an investigation into a dynamic contrast phenomenon in water‐oil emulsions imaged in the environmental scanning electron microscope. Secondary electron contrast between oil and water phases is shown to change with scan rate, even inverting in extreme cases. This effect is attributed to the fact that charge carriers in liquids have intermediate mobilities compared with those in metallic conductors and solid insulators. Thus, increasing the electron energy flux density (via slower scan rates) results in the temporary accumulation of excess charge, which in turn gives rise to increased secondary electron emission. Excess charge dissipates between frames, however, such that classical charging of the specimen is not observed. The oils used here have conductivities lower than that of water, making them more susceptible to the effect. However, the material within the primary electron interaction volume is a conductive medium. We demonstrate that charging effects are not seen in regions of the oil where the interaction volume is in contact with the more conductive continuous water phase. Secondary electron emission from these regions therefore approximates to the intrinsic yield.
The swelling behavior and wet morphology of water‐absorbable polymer materials
Authors: Xia Feng , Chen Fen , Hu Yuxian , Wang Ximei , Lin Shaokun 
Published: June 2010

AbstractIn this research work, a low‐temperature examination method for scanning electron microscopy (SEM) is introduced. A water‐absorbable polymer material, the sulfonated polyethylene (SPE) ion‐exchange hollow fiber membrane, was used for the experiments. With this low‐temperature technique, the wet morphology of the water‐absorbable sulfonated polyethylene hollow fiber membrane was revealed. The results obtained from this investigation offer some important information to explain the behavior of the SPE hollow fiber membranes when they are applied in pervaporation separation of water/ organic solvent mixtures, such as water/ethylene glycol, water/ethanol, and so forth.
Natural color scanning electron microscopy based on the frequency characteristics of the human visual system
Authors: Oho Eisaku , Watanabe Masashi 
Published: June 2010

AbstractThe principles of image formation in natural color scanning electron microscopy (NC‐SEM) are discussed in detail. This method is based on the frequency characteristic of the human visual system. It is shown that the Mach effect and masking effect are important in the characteristics. The former, which can enhance structural details, is visually similar to the edge effect in secondary electron (SE) images, and the latter is required for proper representation of very degraded color information obtained from a light microscope. When using these effects suitably, an NC‐SEM image with the resolution equivalent to that of an SEM image can be acquired, though it is composed of an SEM image and a special video microscopy (VM) image with a resolution much lower than the SEM image of the identical view. The NC‐SEM is more effective than the SEM in observation, interpretation, and analysis of various samples with important color information.
Fundamental problems of imaging subsurface structures in the backscattered electron mode in scanning electron microscopy
Authors: Rau E. I. , Reimer L. 
Published: June 2010

AbstractIn‐depth imaging of subsurface structures in scanning electron microscopy (SEM) is usually obtained by detecting backscattered electrons (BSE). For a layer‐by‐layer imaging in BSE microtomography, it is preferable to use an energy filtering of BSE. A simple approach is used to estimate the contrast by using backscattering coefficients of bulk materials and the maximum escape depths of the BSE. The contrast obtained by BSE energy filtering is about twice that of the standard BSE method by varying the acceleration voltage. The contrast decreases with increasing information depth. The information depth is about four times smaller than the electron range. The transmission of the spectrometer influences the minimum current of the order of 10−8 A that is needed to get a contrast of 1%, for example.
Application of the low‐loss scanning electron microscope image to integrated circuit technology. Part 1– applications to accurate dimension measurements
Authors: Postek Michael T. , Vladár András E. , Wells Oliver C. , Lowney Jerry L. 
Published: June 2010

AbstractScanning electron microscopes (SEMs) are the most extensively used tools for dimensional metrology and defect inspection for integrated circuit technologies with 180 nm and smaller features. Currently, almost all SEMs are designed to collect as many secondary and backscattered electrons as possible. These signals are mainly secondary electrons (SE1, SE2, and SE3) detected with various detection schemes. To facilitate the electron collection, very strong electric and magnetic fields are applied not just in the path of the primary electron beam but to the emerging electrons as well. These new systems provide strong signals, thus better signal‐to‐noise ratio, and thus resulting in higher throughput than older ones. On the other hand, the use of secondary electrons means that measurement results are much more prone to the detrimental effects of electron beam interactions, sample charging, and sample contamination than measurements with higher‐energy backscattered electrons. The use of backscattered electrons, especially low‐loss electrons (LLE), can provide better surface sensitivity, edge accuracy, and repeatability, possibly at the expense of measurement speed. This two‐part study investigates the benefits and drawbacks of low‐loss electron imaging to edge characterization for dimensional metrology and enhancement of fine surface features done through filtration or separation of the generated LLE signal and the use of energy‐dependent signals. Part 1 reviews and illustrates the potential for accurate dimensional measurements at low accelerating voltage by LLE, and Part 2 will concentrate on the enhancement of surface features in chemical‐mechanically planarized specimens with the use of a novel LLE detector.
Light collection efficiency and light transport in backscattered electron scintillator detectors in scanning electron microscopy
Authors: Filippov M. N. , Rau E. I. , Sennov R. A. , Boyde A. , Howell R. G. T. 
Published: June 2010

AbstractExperimentally, scintillator detectors used in scanning electron microscopy (SEM) to record backscattered electrons (BSE) show a noticeable difference in detection efficiency in different parts of their active zones due to light losses transport in the optical part of the detector. A model is proposed that calculates the local efficiency of the active parts of scintillator detectors of arbitrary shapes. The results of these calculations for various designs are presented.
Quality measures in applications of image restoration
Authors: Kriete Andres , Naim Maria , Schäfer Lutz 
Published: June 2010

AbstractWe describe a new method for the estimation of image quality in image restoration applications. We demonstrate this technique on a simulated data set of fluorescent beads, in comparison with restoration by three different deconvolution methods. Both the number of iterations and a regularisation factor are varied to enforce changes in the resulting image quality. First, the data sets are directly compared by an accuracy measure. These values serve to validate the image quality descriptor, which is developed on the basis of optical information theory. This most general measure takes into account the spectral energies and the noise, weighted in a logarithmic fashion. It is demonstrated that this method is particularly helpful as a user‐oriented method to control the output of iterative image restorations and to eliminate the guesswork in choosing a suitable number of iterations.
Application of the low‐loss scanning electron microscope image to integrated circuit technology. Part II— chemically‐mechanically planarized samples
Authors: Wells Oliver C. , McGlashan‐Powell Maurice , Vladár András E. , Postek Michael T. 
Published: June 2010

AbstractChemical‐mechanical planarization (CMP) is a process that gives a flat surface on a silicon wafer by removing material from above a chosen level. This flat surface must then be reviewed (typically using a laser) and inspected for scratches and other topographic defects. This inspection has been done using both the atomic force microscope (AFM) and the scanning electron microscope (SEM), each of which has its own advantages and disadvantages. In this study, the low‐loss electron (LLE) method in the SEM was applied to CMP samples at close to a right angle to the beam. The LLEs show shallower topographic defects more clearly than it is possible with the secondary electron (SE) imaging method. These images were then calibrated and compared with those obtained using the AFM, showing the value of both methods. It is believed that the next step is to examine such samples at a right angle to the beam in the SEM using the magnetically filtered LLE imaging method.
Rapid diagnosis of fungal infection of intravascular catheters in newborns by scanning electron microscopy
Authors: Sbarbati Andrea , Fanos Vassilios , Bernardi Paolo , Tatò Luciano 
Published: June 2010

AbstractIntravascular catheters carry a significant risk of becoming colonized with bacteria and fungi and are important risk factors of septicemia in premature neonates. The study was undertaken to evaluate whether scanning electron microscopy (SEM) examination of removed catheters can be useful in early diagnosis of plastic infection by Candida, providing information useful for initiation of an eventual therapy. The evolution of in the 28 catheters (umbilical or central) implanted in 24 newborns for prematurity was studied by SEM and transmission electron microscopy (TEM). In 4 of 24 patients, SEM examination revealed the presence of Candida in form of yeast or hyphae. In one of these patients, TEM confirmed the presence of organisms. In each case, hemoculture and culture of the catheter itself confirmed the diagnosis. The study demonstrates that SEM can identify fungi in the biomaterials covering the catheter surface in a few hours, allowing an early diagnosis of plastic infection.
Measurement technique for the incident electron current in secondary electron detectors and its application in scanning electron microscopes
Authors: Agemura Toshihide , Fukuhara Satoru , Todokoro Hideo 
Published: June 2010

AbstractA measurement technique for incident electron current in secondary electron (SE) detectors, especially the Everhart‐Thornley (ET) detector, based on signal‐to‐noise ratio (SNR), which uses the histogram of a digital scanning electron microscope (SEM) image, is described. In this technique, primary electrons are directly incident on the ET detector. This technique for measuring the correlation between incident electron current and SNR is applicable to the other SE detectors. This correlation was applied to estimate the efficiency of the ET detector itself, to evaluate SEM image quality, and to measure the geometric SE collection efficiency and the SE yield. It was found that the geometric SE collection efficiency at each of the upper and lower detectors of a Hitachi S‐4500 SEM was greater than 0.78 at all working distances.
A quantitative cryo‐scanning X‐ray microanalysis protocol for the examination of the eye
Authors: Wadley Robert , Junghans Barbara , Dickson Mel , Liang Helena 
Published: June 2010

AbstractAnalysis of elements present in fluids contained in small, poorly accessible sections of biological tissue is challenging. The choroid of the eye, which is a vascular tissue approximately 100 μm thick, surrounds the retina for the purposes of nutrient supply and metabolite removal, and which in the chick shows dramatic volumetric change in response to visual experiences. Because fluid homeostasis is critical to good vision, a complete understanding of the ionic changes driving large shifts in ocular fluids is required. However, the structure of the choroid and retina make extraction of pure fluids for analysis extremely difficult. Elemental x‐ray analysis on a transverse chorioretinal specimen was performed after rapid freezing of a whole chick eye in liquid nitrogen, and mechanically fracturing the frozen globe. Using a Polaron Cryotrans System on a Cambridge S‐360 scanning electron microscope and a Kevex Quantum detector, spectra were obtained for blood vessels, lymphatic vessels and vitreous that were readily visible at 265x. Analysis was performed on a frozen control solution of the elements found in the vessels. The elements and their concentrations found in blood vessels by x‐ray analysis compared well with those from whole blood as established by conventional means. The analysis for lymph yielded results compatible with expectations; no other published data for small lymphatics enable a direct comparison. In conclusion, x‐ray analysis can be used to acquire information that is otherwise unobtainable from tissue in situ. The same bulk‐frozen elemental microanalysis protocol would have application to other organs and tissues when access to the site would destroy the integrity of the tissue under investigation.
Human chromatid ultrastructure: New observations with scanning and transmission electron microscopy
Authors: Jenkins Edmund C. , Wen G. Y. , Jenkins Edmund C. , Genovese Marilyn , Brown W. Ted 
Published: June 2010

AbstractTwo new observations have been made on human chromatid/chromosome ultrastructure using both scanning and transmission electron microscopy (SEM, TEM). A bipartite, apparently half‐chromatid‐like structure was observed in whole human chromosomes studied with SEM and in longitudinally sectioned chromosomes analyzed with TEM. In addition, we also observed a zipper‐like configuration as the parallel sister chromatids separated likely due to the supercoiled structure of the chromosome and chromatid. It is possible that either or both of these new observations resulted from our (improved) method of preparing the chromosomes for SEM and TEM.
Evaluation of Demineralized Dentin Contraction by Stereo Measurements Using Environmental and Conventional Scanning Electron Microscopy
Authors: Dusevich V. M. , Eick J. D. 
Published: June 2010

AbstractNumerous investigations of etched human dentin are performed using scanning electron microscopy (SEM). Usually specimens are fractured and cross sections of etched layers with underlying unaffected dentin are observed. Results from this study showed that the edge of the etched layer contracted and became curved after fracture of wet specimens and that tensile stresses were developed in this layer by acid etching. The degree of contraction was determined utilizing profiles of the specimen edges obtained with the help of stereo measurements. Fixation in glutaraldehyde decreased the contraction in wet specimens prepared for environmental scanning electron microscopy (ESEM). Fixation also decreased shrinkage of the demineralized layer due to gradual desiccation in the ESEM during observation. For conventional SEM, the contraction was minimized if specimens of etched and fixed dentin were fractured in the dry condition after dehydration.
Computer modeling of three‐dimensional reconstruction algorithm of cathodoluminescence material properties, analysis of errors, and optimization of variable parameters
Authors: Ivannikov P. V. , Dronov S. V. , Saparin G. V. , Obyden S. K. 
Published: June 2010

AbstractThree‐dimensional (3‐D) reconstruction of cathodoluminescence (CL) properties of materials (Saparin et al.1997) is a new nondestructive technique that measures quantum yield information of subsurface layers as a set of two‐dimensional image sections. This technique is able to synthesize a 3‐D image without destroying the sample. The basis for this technique is the fact that the electrons in scanning electron microscopy penetrate the sample at different depths with a variation of accelerating voltage. The detected CL emission integrates the information from the full volume occupied by the charge carriers. Estimating the errors that occur during the reconstruction process is complex since these errors are caused by necessary approximations, noise, and the imperfection of the 3‐D reconstruction algorithm that is employed. An analysis of the factors that affect the accuracy of the technique has been made. The estimation of systematic errors and the optimization of variable parameters were calculated by computer modeling.
Second‐harmonic generation from biological tissues: Effect of excitation wavelength
Authors: Deng Xiaoyuan , Williams Elizabeth D. , Thompson Erik W. , Gu X. Gan Min 
Published: June 2010

AbstractWe report on the measurement of second‐harmonic signals from hyperplastic parenchyma and stroma in malignant human prostate tissue under femtosecond pulsed illumination in the wavelength range from 730 to 870 nm. In particular, the relationship of the second‐harmonic generation to the excitation wavelength is measured. The result in these two regions behaves considerably differently and thus provides a possible indicator for identifying tissue components and malignancy.
Dinosaur eggshell study using scanning electron microscopy
Authors: Jackson Frankie D. , Schweitzer Mary H. , Schmitt James G. 
Published: June 2010

AbstractVisualization and analysis of structural features in fossil dinosaur eggs by scanning electron microscopy augment information from traditional petrographic light microscopy. Comparison of characteristics in fossil and modern eggshells allows inferences to be made regarding dinosaur reproductive biology, physiology, and evolutionary relationships. Assessment of diagenetic alteration of primary eggshell calcite structure that occurs during fossilization provides important information necessary for taxonomic identification and paleoenvironmental interpretations.
Lattice‐Like Array Particles on Xenopus oocyte Plasma Membrane
Authors: Lau Joan M. , Xingyou Hong , Yu Lei 
Published: June 2010

AbstractPlasma membrane from Xenopus laevis oocytes has been used as a model system to study membrane structure and particle components, including native and exogenously expressed proteins. Previous studies by electron microscopy (EM) and atomic force microscopy (AFM) compared intramembrane particles (IMPs) on uninjected oocyte membranes to oocytes expressing proteins of interest. These studies observed randomly distributed IMPs on the surface of the oocyte plasma membrane. In this paper, we introduce a novel technique to isolate oocyte membranes by bursting the oocyte and depositing its membrane on a flat mica substrate. The flat surface membrane preparation allows high‐resolution AFM images to be obtained, revealing a novel structure of densely packed particles. These particles exhibit a regular, repeating pattern of a lattice‐like array with orderly packing and are thus termed “lattice‐like array particles” (LAPs). The LAPs are orderly yet imperfectly packed, are located in depressed pools, occur with a low frequency on the oocyte membrane surface, and have not previously been seen using other isolation and imaging methods. Histogram analysis of the center‐to‐center distance between LAPs suggest their size to be about 44 nm in diameter, considerably larger than other reported size estimates of IMPs. These results indicate that LAPs represent a novel membrane particle organization, which merits further study.
Irregular snow crystals: Structural features as revealed by low temperature scanning electron microscopy
Authors: Wergin William P. , Erbe Eric F. , Rango Albert , Foster James , Pooley Christopher 
Published: June 2010

AbstractFor nearly 50 years, investigators using light microscopy have vaguely alluded to a unique type of snow crystal that has become known as an irregular snow crystal. However, the limited resolution and depth‐of‐field of the light microscope has prevented investigators from characterizing these crystals. In this study, a field‐emission scanning electron microscope, equipped with a cold stage, was used to document the structural features, physical associations, and atmospheric metamorphosis of irregular snow crystals. The crystals appear as irregular hexagons, measuring 60 to 90 mm across, when viewed from the aaxis. Their length (c‐axis) rarely exceeds the diameter. The irregular crystals are occasionally found as secondary particles on other larger forms of snow crystals; however, they most frequently occur in aggregates consisting of more than 100 irregular crystals. In the aggregates, the irregular crystals have their axes oriented parallel to one another and, collectively, tend to form columnar structures. Occasionally, these columnar structures exhibit rounded faces along one side, suggesting atmospheric metamorphoses during formation and descent. In extreme cases of metamorphoses, the aggregates would be difficult to distinguish from graupel. Frost, consisting of irregular crystals, has also been encountered, suggesting that atmospheric conditions that favor their growth can also occur terrestrially.
Characterization of atmospheric particles by electron probe X‐ray microanalysis
Authors: Alföldy Bálint , Török Szabina , Trincavelli Jorge , Castellano Gustavo 
Published: June 2010

AbstractMicrochemical glass standards were used to validate a quantitation method based on peak‐to‐background (P/B) ratios from electron probe x‐ray microanalysis spectra. This standardless method was applied to the determination of concentrations of individual particles from Mα or Lα lines, as well as from Kα lines. The algorithm was tested on particulate glass samples for diameters ranging from 1 to 20 μm. The determined concentrations did not depend on particle size. The certified values for elements were well matched, except for Na, which may migrate under electron bombardment. Finally, classification of qualitative results obtained for aerosol particles was completed by the P/B quantitative method.