bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of polymer blends by low voltage scanning electron microscopy
Authors: Berry V. K. 
Published: August 2011

AbstractA technique for characterization of polymer blends by low voltage scanning electron microscopy is described. The method allows observation of the distribution of phases in a blend due to good topographical and compositional contrast. This is possible because of lower beam penetration and high secondary emission coefficient (δ ⩾ 1) at low accelerating voltages. Uncoated polymer samples are imaged with no charging or beam damage problems. The technique has a great advantage over conventional transmission electron microscopy techniques because the sample preparation is minimal and larger areas can be prepared for viewing.
Scanning reflection image from a solid specimen in the scanning electron microscope with a condenser‐objective lens
Authors: Wells O. C. 
Published: August 2011

AbstractTo achieve the highest resolution in the scanning electron microscope (SEM) or in the scanning transmission electron microscope (STEM), the sample must be mounted in the high‐field region of a condenser‐objective lens. A secondary electron (SE) image can then be obtained using a collector before the lens. It is also possible to obtain a scanning reflection image by tilting the specimen so that the second half of the condenser‐objective lens field deflects the forward‐scattered electrons onto the transmission detector beyond the specimen. Experiments were made with an unmodified commercial SEM fitted with a condenser‐objective in the upper stage and with a transmission detector, and it was found that the scanning reflection image from a solid sample can provide additional useful information when used in conjunction with the SE image.
A computerized signal acquisition system for the quantitative evaluation of EBIC and CL data in a SEM
Authors: Bode M. , Jakubowicz A. , Habermeier H.‐U. 
Published: August 2011

AbstractElectron beam‐induced current (EBIC) and cathodoluminescence (CL) are widely used methods to obtain information about recombination properties of semiconducting materials and their defects on a micrometer length scale. In this article a computerized SEM (scanning electron microscope) setup is described, which enables us to perform simultaneous measurements of several signals and automatic temperature‐dependent measurements. As examples for the performance of this system we present results obtained by simultaneous EBIC/CL experiments, allowing a reconstruction of the defect geometry. In a second example, the temperature dependence of the EBIC contrast is analyzed, introducing the method of EBIC spectroscopy.
Elemental imaging by electron energy loss microscopy
Authors: Ottensmeyer F. P. , Andrews D. W. , Arsenault A. L. , Heng Y. M. , Simon G. T. , Weatherly G. C. 
Published: August 2011

AbstractElectron energy loss images obtained by parallel filtration at selected energies are used to derive qualitative and quantitative distributions of elements in specimens as diverse as low alloy steel, cartilage, and ribosomal particles. Partial ionization cross‐sections for electron scattering from phosphorus L‐shells are calculated.
Absorbed current: A source of information about voltage relations on measured specimen
Authors: Hamerlik R. 
Published: August 2011

AbstractIt is shown that a change in the SE current is opposite and equal in magnitude to a change in the absorbed current. Thus using the effect of potential contrast, allows measurement of voltage changes on a specimen by means of changes in the absorbed current. The present method offers a new possibility to complementary information, which can be helpful in various cases.
A PC‐AT‐based system for the acquisition of SEM images
Authors: Morandi C. , Vanzi M. , Bianco F. , Neri R. 
Published: August 2011

AbstractA system for the acquisition of high‐quality DDVC (digital differential voltage contrast) images based on a low‐cost personal computer and a dedicated scanning electron microscope interface is described. It is capable of obtaining high‐quality voltage contrast maps of passivated integrated circuits even on supply lines, which are not usually seen due to static biasing. Grey‐level and colour image‐comparison utilities allow effective state‐by‐state comparison of a failed device with a good one, and are extremely useful for failure analyses.
A phase‐shift technique for high‐speed e‐beam testing with picosecond time resolution
Authors: Winkler D. , Schmitt R. , Brunner M. , Lischke B. 
Published: August 2011

AbstractElectron beam sampling of high speed digital devices requires a high time resolution. At the same time, long‐range phase shifting is necessary because signals in these circuits may have very long period lengths. In this article, a new phase‐shift method is described which allows sampling of low repetition rate signals without any degradation of the time resolution. This long range phase shift is realized by an additional set of blanking plates or blanking capacitor, which, acting as a gate, selects one of a large number of electron pulses produced by a first blanking capacitor. This technique also allows fast switching between different phase angles. The phase‐shift method was evaluated experimentally using the picosecond e‐beam tester which was developed here. The time resolution of this tester has been optimized recently to allow for stroboscopic testing with a 7 ps pulse width at 20 mV/√Hz noise voltage and 0.5 μm spot size. This allows for the measuring of rise times down to 14 ps with an error below 10%. Phase shifts of 100 ns were realized without any degradation of this time resolution. Propagation delays of 3.5 ps could be resolved. Signal rise times of 40 ps, corresponding to 0.04% of the total delay could be easily measured.
Advantages of visualization of organelle structure by high resolution scanning electron microscopy
Authors: Hollenberg M. J. , Lea P. J. 
Published: August 2011

AbstractExamination of subcellular structures in detail and in three dimensions (3D) by scanning electron microscopy (SEM) is now possible on a routine basis due to improvements in design of the modern scanning electron microscope and new methods of specimen preparation involving chemical removal of the cytosol and the cytoskeleton. Cells which have been fixed, frozen, cleaved, thawed, and subjected to cytosol removal exhibit constituents such as nuclear chromatin, cisternae of endoplasmic reticulum, mitochondria, and the Golgi complex in bold relief. This permits examination by SEM in 3D of these structures from several aspects at a resolution close to that of conventional transmission electron microscopy (TEM). As a result, minute changes in the 3D structure of subcellular components can now be easily and conveniently examined from many specimens and anatomical sites, in development, in a variety of physiological processes, and in disease. The SEM method offers many advantages over the various TEM techniques now used for similar purposes, since much larger areas of the specimen can be surveyed by SEM in a given time, sectioning is not required and minute 3D changes in nuclear and organelle structure can be identified and analyzed more easily. The advantages are such that a host of biological questions can now be answered by SEM which, so far, have resisted solution using only TEM techniques. In addition, a new field of pathological diagnosis using SEM may develop, using the advantages offered by the technique in exploring the cell's interior as well as cellular tissue organization.
Cathodoluminescence and transmission electron microscopy of an abrupt lateral junction in algaas grown by molecular beam epitaxy
Authors: Hoenk M. E. , Vahala K. J. 
Published: August 2011

AbstractWe present evidence for a novel type of junction, lateral to the growth direction, in AlGaAs grown by molecular beam epitaxy. Cathodoluminescence data show an abrupt change in the bandgap of AlGaAs grown in grooves on a GaAs substrate at the boundary between adjacent facets. Transmission electron microscopy of a cross section of the groove reveals an unexpected quasiperiodic compositional modulation on the (111) facets of the grooves. The transition in the bandgap occurs as a result of abrupt termination of the compositional modulation at the facet boundaries.
The use of a novel image‐shearing technique on a scanning electron microscope for comparative measurement of linewidths on photomasks
Authors: Nunn J. W. , Turner N. P. 
Published: August 2011

AbstractA technique for measuring the widths of lines on chromium‐on‐glass photomasks is described which combines the resolution of the scanning electron microscope (SEM) with the accuracy of a helium‐neon laser interferometer, and the setting sensitivity of image‐shearing methods. Electron microscope image intensity profiles and the choice of signal which yields the best measurement repeatability are discussed. The technique described here yields measurements which are relatively insensitive to defocus and beam diameter.
Electron beam testing of circuits at liquid nitrogen temperature
Authors: Jenkins K. A. , Immediato M. J. , Heidel D. F. 
Published: August 2011

AbstractAn electron beam tester has been modified so that circuits being tested can be cooled to liquid nitrogen temperature. This enables voltage contrast imaging, and internal node probing, of low‐temperature circuits. Waveform measurements made in this way reveal details of low‐temperature circuit operation which cannot be easily obtained by any other means.
A modification of the ET secondary electron detector with a single crystal scintillator
Authors: Autrata R. 
Published: August 2011

AbstractOn the basis of the study of optical properties of single crystal YAG scintillators, it has been found that the maximum light output signal propagated in the required direction in the scintillator of a secondary electron detector is obtained if a cone‐shaped scintillator is used. A modified Everhart‐Thornley (ET) detector containing a conical scintillator and an electro‐optical diaphragm operated at a positive voltage shows an increase to 2.8 times the light output signal of the classical ET detector with a flat single crystal YAG scintillator disc. The modification allows optimization of the suction of secondary electrons toward the scintillator and of the propagation of light from the scintillator toward the light guide.
Scanning slit aperture confocal microscopy for three‐dimensional imaging
Authors: Burns D. H. , Hatangadi R. B. , Spelman F. A. 
Published: August 2011

AbstractA scanning confocal microscope using stationary slit apertures of variable width is described. Scanning is achieved by employing an oscillating mirror galvanometer capable of scanning images at 160 frames/s. The microscope depth‐of‐focus is characterized for several slit widths and shown to approach diffraction‐limited performance as width decreases. Reduction of flare in images taken with narrow slit widths is demonstrated. In addition, the optical sectioning capability of the system is demonstrated using polymer casts of the vasculature of rat kidney.
Observation of the rabbit cornea and lens with a new real‐time confocal scanning optical microscope
Authors: Xiao G. Q. , Kino G. S. , Masters B. R. 
Published: August 2011

AbstractA new one‐sided tandem scanning microscope (OTSM) has been utilized to optically section a transparent cornea and ocular lens with submicron depth and transverse resolution. Its high resolution, image quality, and contrast, together with color capability, real‐time operation, and easy alignment, have advantages over previous confocal systems. Planes within the nuclei of surface epithelial cells, the epithelial basement membrane, nerve fibers, the interior of endothelial cells, and the transverse structure of the lens fibers are readily observed. The utility of real‐time microscopic observation of live biological structures provides a new paradigm for cell biology and diagnostic ophthalmology.
Charging phenomena on insulating materials: Mechanisms and applications
Authors: Le Gressus C. , Valin F. , Gautier M. , Duraud J. P. , Cazaux J. , Okuzumi H. 
Published: August 2011

AbstractWe are interested in the physical origin of the electric charge that is produced in insulators by electron bombardment, by an electric field, or by mechanical stress. The charge is due to the trapping of carriers on the defects formed in the course of the dissipation of energy by the lattice. The characteristics of the charge (potential, electric field) result from the laws of electrostatics. The stability of the charge under an electron beam is interpreted on the basis of the laws governing the behavior of the discharges in gases and in solids. The stability of the charge after shutting off the beam depends on the position of the traps with respect to the surface and the experimental conditions (gas pressure, temperature, time). The charge decay kinetics are then controlled by adsorption‐diffusion. These studies allow us to explain some of the electromigration phenomena that had not been interpreted and to determine the optimal experimental conditions for the observation of local variations in the dielectric constant; they also allow the use of the charge phenomenon as an indicator of the mechanical and dielectric properties of insulators.
Comparison between the experimental and theoretical modeling of linewidth measurements on photomasks and their insensitivity to accelerating voltage in the scanning electron microscope
Authors: Nunn J. W. 
Published: August 2011

AbstractA technique for measuring linewidths on chromium‐on‐glass photomasks in the SEM is described. The experimental observation that the width at the 50% intensity levels of the backscattered electron image intensity profile is largely insensitive to the accelerating voltage is backed up through Monte Carlo trajectory calculations. The theoretical model yields results which can be used to predict the position of the true edge from experimental intensity profiles to within 0.01 μm.
Sphincterlike structures in corrosion casts
Authors: Aharinejad S. , Franz P. , Böck P. , Lametschwandtner A. , Breiteneder H. , Firbas W. 
Published: August 2011

AbstractCorrosion casts of the microvascular bed often show superficial constrictions, which may be interpreted as sphincters. In the present investigation, scanning electron microscopy (SEM) of vascular corrosion casts and transmission electron microscopy (TEM) of sectioned material were combined to obtain evidence on the wall structure in those regions where constrictions are seen. The study was performed on the microvasculature of the exocrine pancreas of rats and mice. Constrictions on casts of fenestrated or nonfenestrated capillaries correspond to cytoplasmic processes of pericytes. In the case of irregular superficial furrows and grooves on postcapillary veins and collecting venules the same situation is seen. Pericytes are not interpreted as sphincters. Deep constrictions were observed on casts of collecting venules in SEM, while in TEM they were shown to be caused by circular smooth muscle cells. The constrictions cause significant narrowing of the vascular lumen and are consequently interpreted as sphincters. Drastic narrowing of the capillary lumen was also seen where capillaries merge into postcapillary veins. TEM revealed the presence of pericytes in these regions. In our opinion, these narrowings functionally resemble sphincters, but there is no evidence for controlled closure and reopening as yet. Methodological conditions during tissue preparation, which may influence the appearance of casts in SEM, are discussed.
Cathodoluminescence of natural diamonds from Jakutian deposits
Authors: Zezin R. B. , Saparin G. V. , Smirnova E. P. , Obyden S. K. , Chukichev M. V. 
Published: August 2011

AbstractWe recount the study of plates cut from natural diamonds of mineralogical types I and IV with the use of optical polarization microscopy, photo‐ and cathodoluminescence (CL). A series of specimens exhibited two macroscopic zones of different structures characterized by the alternation of crystalline regions with different nitrogen contents. Diamonds are block structures with a lower nitrogen content. CL spectra were observed from central, intermediate, and peripheral zones of the plates. The crystal growth mechanism is discussed, and an attempt is made to correlate the spectroscopic measurements with the CL images formed in a color SEM. The findings may be useful in establishing a criterion to assess diamonds for certification.
Recent advances in scanning x‐ray microscopy
Authors: Morris D. , Buckley C. J. , Morrison G. R. , Michette A. G. , Anastasi P. A. F. , Browne M. T. , Burge R. E. , Charalambous P. S. , Foster G. F. , Palmer J. R. , Duke P. J. 
Published: August 2011

AbstractA scanning x‐ray microscope has been built at the Daresbury synchrotron radiation source and used to obtain images at soft x‐ray wavelengths (∼2–4 nm). The focusing element of the microscope is a zone plate, fabricated by a contamination writing process developed at King's College. Zone plates with the finest zone widths, and hence theoretical resolutions, below 20 nm have been fabricated in this way. The contamination material is carbon, and as such is unsuitable for high‐efficiency focusing. In order to increase the zone plate efficiency, a shadowing pattern transfer process has been developed and used to replicate contamination lines with 25 nm widths into more suitable materials.
Measurement of microscopic displacements in graphite/epoxy composite materials using SEM‐generated fiducial markers
Authors: Burghardt R. C. , Ehrman J. M. , Stephens T. C. , Hibbs M. F. , Bradley W. L. 
Published: August 2011

AbstractGraphite fiber‐reinforced resin composite materials are widely used in commercial applications where high strength and low weight are critical factors. In order to predict the fracture toughness of a composite material from the constitutive properties of the resin and fibers, experimental methods for the analysis of microscopic displacements and strain fields that develop at the fracture crack tip within the composite material are required. Information derived from measurement of displacements, and calculation of strain fields can then be used to test micromechanical models of matrix‐dominated fracture. A method was developed in which it is possible to conduct near real‐time fracture analysis of epoxy‐based composite materials, and to subsequently obtain micrometer‐scale measurements of displacements in the region of the crack tip. A map matrix was generated on the surface of test specimens in an SEM equipped with a tensile stage, along with an x‐ray spectroscopy and image analysis system. A 40 × 40 point digital map was introduced onto the surface of the specimen using the digital x‐ray mapping function of the x‐ray analysis system which produced a surface matrix with point spacing of 10 μm. The quality of maps varies with test specimens and therefore it is necessary to optimize microscope operation parameters for each resin tested. Reproducible results were obtained with both neat resins and graphite/epoxy composites. In situ analysis of a region of a propagating crack tip grown using the tensile stage reveals a deformation zone ahead of the crack tip and images of the stages of microcracking were captured by the image analyzer for subsequent measurement of displacement. Direct measurement of crack tip displacements from SEM electron beam‐induced reference matrices provide an important tool in characterizing the fracture behavior of both neat resin and composite materials.
Problems of low‐light detection in real‐time at high resolution
Authors: Gursky H. , Fritz G. 
Published: August 2011

AbstractVarious kinds of low‐light‐level detectors and image intensifiers are described and specific charge‐coupled device (CCD) developments are discussed from the perspective of the astronomical community, with possible application to optical microscopy. A number of research groups are reporting success at obtaining custom CCDs for application to high‐quality cameras working at low‐light levels. CCDs offer significant advantages in image quality and sensitivity compared with more traditional devices. Signal to noise (S/N) is derived for both CCDs and intensified devices. There is a tradeoff between the two and, because of the high read‐out rate required by microscopists, intensified devices still offer a S/N advantage at the lowest light levels.
The application and programming of an image store for the SEM
Authors: Hall M. G. , Hulbert J. K. , Zarucki P. N. 
Published: August 2011

AbstractThe programming and use of a purposebuilt digital image store constructed for a SEM is described. The system is based on purpose designed circuitry controlled by a Motorola MC68000 and is capable of noise‐averaging using multiple frames, colour look‐up tables, high‐resolution photographic recording, image processing using matrix functions, some image quantification, and x‐ray spectrum acquisition. The way in which the FORTH language provided an efficient means of controlling the SEM is described and examples of each type of operation are presented.
Signal strength and noise in confocal microscopy: Factors influencing selection of an optimum detector aperture
Authors: Sheppard C. J. R. , Cogswell C. J. , Gu M. 
Published: August 2011

AbstractIn confocal microscopy, several factors influence the selection of an optimum size and geometry of detector aperture. These include (1) strength of signal from the specimen, (2) noise level in the system, (3) optical configuration of the microscope (e.g., reflection or fluorescence), (4) time available for signal accumulation, (5) specimen thickness, and (6) amount of reduction in axial and transverse resolution (from the theoretical maximum) that can be tolerated. It is shown both theoretically and experimentally that the size of the detector aperture critically influences the type and amount of system noise that is detected along with the specimen signal. It is also demonstrated that increasing the size of the detector pinhole does not appreciably increase the signal strength from any single thin plane, but only increases the sampling depth, enhancing brightness at the cost of a reduction in axial resolution. As a result, it is shown that there is no advantage, from the standpoint of signal strength, to using a slit aperture rather than a circular detector pinhole. Finally, it is concluded that all confocal microscopes should be designed to allow the user the capability of selecting ah optimum compromise detector aperture setting based on the particular specimen properties, type of microscopy (e.g., fluorescence or reflection) and resolution required.
Complementary optical and electron microanalysis of high‐temperature superconductors
Authors: Hoff H. A. , Lechter W. L. , Toth L. E. 
Published: August 2011

AbstractScanning electron microscopy coupled to quantitative energy‐dispersive x‐ray spectroscopy provides an excellent tool for determining the compositions of various cuprate superconducting phases in the course of processing from insulator to superconductor. When coupled with a new room temperature optical microscopy technique for the identification of individual superconducting grains, it provides a complete picture of the processed state of the material. The techniques are complementary. Two different materials were examined with both optical and electron microscopy: (1) a Tl‐Sr‐Ca‐Cu‐O system superconducting material doped with Hg and (2) a metallic, but not superconducting La‐Sr‐Cu‐O system material. The results and the complementary nature of optical and electron microscopy in assessing the stoichiometry and homogeneity of these materials are described.