bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorescent Spectroscopy of Mineral and Material Samples
Authors: MacRae CM , Harrowfield I R , Wilson N , Yoshiya M , Fazey P , Peacock S , de Yong L , Adachi H 
Published: July 2020

Abstract
Wavelength dispersive spectrometry of long wavelength lines by EPMA can give information on the site symmetry and bonding of the x-ray-emitting atom. For fully focussing spectrometers, the energy resolution can be as high as 2eV or better at a spatial resolution of 1 μm, but electron beam currents often must be set to damaging levels. Fluorescent spectroscopy of the same lines in the commercial laboratory XRF spectrometer is far less damaging but spatial resolution is non-existent or, with collimators, relatively poor. With a combination of electron induced and x-ray induced fluorescent spectroscopy, and the insight provided by molecular orbital calculations, speciation or state analysis can be achieved even on damage prone specimens.
Electron and x-ray induced fluorescence has been employed to investigate surface coatings on magnesium metal. Oxygen Kα spectra for crystalline MgO, MgCO3 and powdered 4MgCO3.Mg(OH)2.5H2O were recorded using a TAP(2d=2.5757 nm) analysing crystal on a JEOL 8900R EPMA and a Philips PW 1404 XRF.
Electron Microprobe Reference Materials for Geologic Analysis a Need for Developing Strategy
Authors: Jarosewich Eugene 
Published: July 2020

Abstract
Each field of electron microprobe analysis has its own specific analytical difficulties. Problems relating to the analysis of geologic materials can be primarily attributed to the fact that the samples are nonconductive, some are unstable under the beam, and they have a complex matrix. There are various techniques to solve these analytical problems, but the selection of appropriate standards is one of most important factors.
In study of geologic materials a convention prevails that the summation approximates 100%. For most analyses summation is an indication of the quality of analysis, although some elements could be over or under corrected. Significant progress has been made in developing correction procedures, yet some fundamental parameters still are not well known, and the results will vary depending on which procedures or fundamental parameters are used. One of the most practical solutions to eliminate significant matrix effects is to select reference materials with a close composition to the unknown.
A Basalt Glass Standard for Multiple Micro Analytical Techniques
Authors: Meeker GP , Taggart JE , Wilson SA 
Published: July 2020

Abstract
Well-characterized calibration standards for microanalytical applications are difficult to obtain, often poorly characterized, and often not homogeneous from piece to piece. In addition, many microanalytical standards are available only in very small quantities making inter-laboratory comparisons difficult. To further complicate the situation, destructive microbeam techniques such as secondary ion mass spectrometry (SIMS) and laser source mass spectrometries (LSMS) require larger quantities of material than nondestructive techniques.
The U.S. Geological Survey, Geologic Division is in the process of evaluating ways to produce relatively large quantities of well-characterized standards. We are interested in producing standards of geological materials appropriate for multiple microbeam techniques including electron probe microanalysis (EPMA), SIMS and LSMS. The microbeam standards are produced by melting powders of standards of naturally occurring materials that the USGS has previously provided as bulk analytical standards.
Factors Affecting the Performance of Backscattered Electron Detectors at Low Beam Accelerating Voltages in SEM
Authors: Robinson V N E 
Published: July 2020

Abstract
The use of backscattered electron (BSE) imaging in low voltage scanning electron microscopy (SEM) has increased over the past few years. This appears to be due to several factors including improved performance of SEMs at low voltages, reduced beam penetration, more reliable metrology, improved atomic number (Z) contrast information (for low Z) and reduced charging artefacts over secondary electron (SE) imaging. Understanding the factors involved in low voltage BSE detection may assist in improving the information attainable.
It has been shown that the signal Sdet from a BSE detector, for EB ≫ Ew is given by

where η is the BSE yield, Ω is the solid angle subtended by the detector to the specimen, D is the internal conversion efficiency of the detector, EB is beam accelerating voltage, Ew is the energy barrier of the dead layer on the detector's surface, IB is the beam current, F(Z) and F(Ω) are functions which take into account the variation of BSE energy with atomic number Z and collection angle respectively.
Chemical Quantitative Analysis of Small Precipitates in the FE-SEM Using the Energy Distribution of Backscattered Electrons
Authors: Gauvin Raynald 
Published: July 2020

Abstract
Low voltage scanning electron microscopy with a field emission source allows characterization of materials with high spatial resolution. This high resolution comes from the low incident energy which gives a small interaction volume (about 10 nm in Fe at 1 keV ), from the field emission source which gives a small probe size (about 2.5 nm in the most recent FE-SEM) and from virtual, or through the lens, secondary electron detectors with gives high collection efficiency and eliminates some of the SEII and all the SEIII- For example, it has been shown that 10 nm NbC inclusions in steels can be imaged in such FE-SEM at 2 keV (this work was performed with a HITACHI S-4500). However, quantitative x-ray analysis of such precipitates are difficult because the critical ionization energy of the Nb Lα lines is equal to 2.37 keV, an incident electron energy of at least 5 keV must be used to get significant x-ray counts rates.
Wool and Cashmere Fiber Identification Study Using Scanning Electron Microscopy
Authors: Baker J D , Lentz H P , Kritikos D G , Schamber FH , Lee R J 
Published: July 2020

Abstract
Despite the large production and consumption of textile fibers on a global basis, the ability to identify specific types of textile fibers with similar physical-chemical properties is a challenging obstacle for the textile industry. One problem in particular is the identification of specialty animal fibers. Cashmere is a specialty fiber that has a value of 7 to 8 times higher than its similar counterpart wool. It is important, therefore, for textile manufactures to be capable of distinguishing between bails of high value specialty fibers and those containing contamination from lower value products.
Today the universally accepted method of identifying fibers is microscopic analysis. However, the optical microscope is limited because of the subjective nature of the analysis and its limited ability to easily measure different parameters of the fiber such as the fiber diameter, the fiber scale length and the fiber scale thickness.
Use of the Disk-of-least-confusion in X-ray Microanalysis
Authors: Kenik E A , Ren S X 
Published: July 2020

Abstract
Whereas the spatial resolution for standard secondary electron (SEI) imaging in a scanning electron microscope or electron probe microanalyzer is related to the incident probe diameter, the spatial resolution for x-ray microanalysis is related to the convolution of the probe diameter with the spatial extent of the analyzed volume for a point probe. The latter is determined by electron scattering in the specimen and the subsequent emission of excited x-rays from the specimen. As such, it is possible that “What you see is not what you get”. This is especially true for instruments with high brightness electron sources (field emission). This problem is compounded by probe aberrations which at Gaussian image focus can produce significant electron tails extending tens of microns from the center of the probe.
Quantifying SEM Resolution and Performance
Authors: Joy David C , Völkl Edgar 
Published: July 2020

Abstract
The ability to reliably and quickly determine the resolution of the scanning electron microscope (SEM) is highly desirable becauseonly then can the level of performance which is being achieved be compared to that which was anticipated or specified. Further, in activities such as automated line width measurements, or in telemicroscopy, the ability to quantify the imaging performance provides the remote operator with the necessary information to monitor, document, and optimize the instrument set-up. However, compared to the equivalent task on the transmission electron microscope (TEM) an analysis of SEM performance is hampered by poor signal to noise ratios, and the absence of ideal ‘white noise’ samples.
The two dimensional Fourier power spectrum of an image provides a readout of the frequency content of the information present in the micrograph. From an analysis of the power spectrum the highest spatial frequency transferred in the image can then be determined and hence the resolution of the micrograph can be specified.
Microstructure and Microtexture in Nb-Silicide Based Composites
Authors: Bewlay BP , Sutliff JA 
Published: July 2020

Abstract
Directionally solidified in-situ composites based on niobium and niobium silicides, such as Nb5Si3 and Nb3Si, are presently under investigation as structural materials [1, 2], Alloying additions of elements such as Hf, Ti and Mo to these silicides are also being explored in order to increase strength and oxidation resistance. The present paper describes the effect of Hf, Mo and Ti additions on microstructure and microtexture of high temperature silcide-based in-situ composites.
Alloys were prepared from high purity elements (&gt;99.9%) using induction levitation melting in a segmented water-cooled copper crucible. The alloys were directionally solidified using the Czochralski method [2], Phase identification was performed using scanning electron microscopy, electron microprobe analysis (EMPA), and automated electron back scattering pattern (EBSP) analysis. Using EBSP, positive phase identification was accomplished by direct comparison of the location and character of the diffraction bands in the experimental pattern with those calculated from simulated patterns generated using the possible structure types.
Evaluation of Boron Nitride Coated Nextel 312TM Fiber/BlackglasTM Composites Using an Environmental SEM
Authors: Schalek Richard L , Helmuth John , Drzal Lawrence T 
Published: July 2020

Abstract
The most critical technical issue preventing large scale application of ceramic matrix composites is the cost-effective application of stable interface coatings on continuous ceramic fibers. Currently, an alumina-silica ceramic fiber containing up to 14 wt. % boria (Nextel 312TM) is composited at elevated temperatures to form a boron nitride (BN) coating on the fiber surface. This BN coating serves as a compliant layer facilitating crack deflection and producing a non-catastrophic failure mode. Continued development of these ceramic matrix composites requires a more complete understanding of the mechanistic paths involved in composite densification. The objective of this work is to investigate and more clearly describe the role of the BN coating and its relation to composite processing and properties of the densified Nextel 312TM fiber/BlackglasTM (silicon oxycarbide) composites.
Three composites consisting of as-received fibers (coated with an organic sizing), desized fibers (sizing removed by heating), and boron nitride coated fibers were fabricated using BlackglasTM preceramic polymer 489C B-stage resin.
‘Cool ESEM’ - Imaging Ice-Containing Systems at Freezer Temperatures
Authors: Fletcher AL , Keller TH , Thiel BL , Eddy AE , Donald AM 
Published: July 2020

Abstract
Conventional scanning electron microscopy permits the use of cryogenic techniques, which has led to the examination of ice-containing samples (eg ice cream) at temperatures of -80°C and below. At these temperatures moderate etching of the ice crystals occurs which helps to identify the crystals in the surrounding glassy matrix. However, imaging at higher temperatures - equivalent to those at which most ice-containing systems are actually utilised - is impossible because of rapid sublimation. We have set out to develop a system which will enable us to examine ice crystals at temperatures of -20°C and below, corresponding much more closely to realistic conditions of use.
In the environmental scanning electron microscope (ESEM), a gas can be maintained around the sample. Not only can this be used to maintain the sample in its native state, but the gas is actively involved in the imaging process through its role in signal amplification.
Secondary Electron Contrast in Molecular Liquids
Authors: Thiel BL , Stokes DJ , Donald AM 
Published: July 2020

Abstract
Liquid containing specimens can be stabilized for observation in the Environmental Scanning Electron Microscope (ESEM). It is also possible to examine systems that are primarily liquid, such as colloidal suspensions and gels, or even possess a multi-component liquid microstructure as in emulsions.(l) In order for such investigations to be useful, an understanding of the origins of secondary electron contrast in liquids is necessary. Our aim here is not to produce a complete theory of secondary electron emission in these systems, but to provide general guidelines for discriminating between two liquids based on relative contrast.
Secondary electron emission from a substance is determined by three processes: creation, transport through the material, and escape from the surface.(2) Contrast between two regions will be due to differences in one or more of these processes. Initial generation of secondary electrons is primarily a function of the ionization cross-sections of the substance and its density.
Charge Contrast: Some ESEM Observations of A New/Old Phenomenon
Authors: Doehne Eric 
Published: July 2020

Abstract
Over the past few years there have been occasional reports of unusual secondary electron contrasts in certain nonmetallic materials using conventional (CSEM-Johansen et al, 1997), low voltage (LV-SEM-Harker et al, 1993; Harker et al, 1994) and environmental scanning electron microscopy (ESEM-Griffin, 1997; T. Hardt, personal communication) which have documented novel contrast mechanisms whose origins are not yet well understood. Indeed, similar observations were made over 20 years ago in certain uncoated materials (such as SiC) using conventional SEM (Sawyer and Page, 1978). Aspects of these charge contrast imaging (CCI) phenomena are further documented here in a series of ESEM experiments on polished cross sections of uncoated travertine calcite. What is “old” is the fact that these contrasts have been reported on several occasions. What is “new” is the observation that these unusual contrasts are more readily studied and, in some cases, have been found in a wider range of materials using ESEM.
Operating Conditions For Quantitative X-Ray Analysis In The Environmental SEM
Authors: Carlton R A , Lyman C E , Roberts J E 
Published: July 2020

Abstract
Standard Reference Material (SRM) 482 of the National Institute of Standards and Technology is a set of 6 gold/copper wires, ranging in concentration from 0 to 100% Cu in 20% steps, intended for calibration studies of electron beam microanalyzers. This is an appropriate standard to test the accuracy of energy dispersive x-ray spectrometry (EDS) in the Environmental Scanning Electron Microscope (ESEM). While the presence of the gas in the sample chamber gives the ESEM its unique capabilities, it also is the source of complications to x-ray spectrometry. The gas can spread the primary electron beam into a wide skirt of electrons with the consequent production of x-rays many micrometers from the target location of the beam. In spite of the difficulties, at least two methods have been proposed to correct high pressure data to that expected at low pressures.
Ordering of a Functional Molecules on a Flat Surface as Evidenced by Scanning Probe Microscopies: The Case of a Di-Alkyl Amino Group
Authors: Gorman Christopher , Touzov Igor , Miller Russell 
Published: July 2020

Abstract
Our group is interested in exploring how functional molecules (e.g. those composed of organic functional groups that do not necessarily lend themselves to an ordered 2D packing arrangement) can form well-ordered adlayers with functional properties. To this end. we have studied the formation of self assembled structures of 5-(N,N-didecyl-amino)-2.4- pentadienal (DAPDA, Figure 1) deposited on a highly ordered pyrolytic graphite (HOPG) surface. This molecule has two distinctive features that should dramatically affect its ordering on a surface. Neither of these have been systematically explored in ordered adlayers. First, the extended conjugation of the molecule gives it a large in-plane dipole moment as well as a high polarizability. Second, it contains two hydrocarbon tails, only one of which can lie coplanar with the conjugated moiety. Both molecularly resolved monolayer and bilayer structures were found using a combination of scanning tunneling microscopy and tapping mode atomic force microscopies.
Langmuir-Blodgett Film Stability Via Atomic Force Microscopy
Authors: Takamoto Dawn Y 
Published: July 2020

Abstract
Langmuir-Blodgett (LB) films of fatty acid salts are inherently unstable due to the fundamental incompatibility of the asymmetric monolayer film transferred from the water surface with the centrosymmetric equilibrium form of the fatty acid bulk crystal. One consequence of this incompatibility is that fatty acid salt films deposited by the LB technique do not remain as flat and uniform films, but reorganize into bilayer step islands. By using mixed chain length films, the islands and holes had distinct heights that suggest this reorganization occurs by a bulk folding of the layers rather than a molecular reorganization of the molecules.
We have studied cadmium arachidate (CdA) LB films, varying the substrate used, the number of layers deposited, and the time the film spends under the aqueous subphase. All films were imaged in air with an Atomic Force Microscope (AFM).
Atomic Force Microscopy Studies of Microstructure and Properties of Self Assembled Monolayers
Authors: Santiago Jecksan R , Barry Troughton E , Dennis Richard A , Russell Phillip E 
Published: July 2020

Abstract
Ex-situ and in-situ studies were performed for self-assembled monolayers (SAMs) formation on mica. The behavior of two surfactants [octadecylphosphonic acid (OPA) and dodecylphosphonic acid (DPA)] in two different solutions [ethanol or tetrahydrofuran (THF)] were studied at different concentrations. A cross section analysis of the monolayer images at partial coverage showed thickness of 1.8 nm, 0.7 nm, and 1.0 nm for OPA, DPA and mixed OPA/DPA, respectively. These values are similar to the ones presented by Xiao and those expected for a monolayer of mixed surfactants as proposed by Whitesides. Since the topography of a monolayer resembles the substrate, the presence of the monolayer at full coverage was determinated by force-distance curve measurements. It was observed that the solvent had the ability to re-dissolve the OPA monolayer, suggesting that the bonding is of a physisorption nature.
A Novel Preparation Method for High Resolution AFM Introduced With 2d-Streptavidin Crystals Grown on a Biotinlipid Monolayer
Authors: Scheuring Simon , Müller Daniel J , Ringler Philippe , Bernard Heymann J , Engel Andreas 
Published: July 2020

Abstract
The AFM (atomic force microscopy) requires a stable and flat substrate on which a biological sample is readily immobilized. For instance, membrane protein 2D crystals in lipid bilayers have been adsorbed to silanized glass with covalently attachment using a photocrosslinker or to mica by physisorption under appropriate ionic conditions. For the immobilization of 2D crystals of water soluble proteins formed on lipid monolayers, a different approach is required to attach the highly hydrophobic tails of the lipid molecules. To find a suitably hydrophobic substrate, the hydrophobicity of different materials was determined by the sitting drop method. Briefly, a 10 μ1 droplet of deionized and filtered water was deposited on the substrate surface and the diameter measured. Table 1 shows a decrease in droplet diameter with increasing hydrophobicity, indicating that substrates such as silanized glass and HOPG (highly ordered pyrolytic graphite) may be suitable for adsorbing lipid monolayers.
TEM Analysis of Deformation Zones in FIB-Prepared Samples of Microploughed Gold (100) and (111) Surfaces
Authors: Day R D , Dickerson R M , Maggiore C J , Brooks P M , Russell P E , Woodward T , Carter C B 
Published: July 2020

Abstract
To improve the understanding of the mechanical deformation mechanisms associated with friction, wear, and precision machining processes, a detailed set of microploughing experiments were performed on gold single crystal surfaces. Large single crystals that had an edge length of 1.5 mm and a thickness of 1 mm were used for this work. Since the microplough depths ranged from 100 nm to 1600 nm, it was important that the material be damage free at the surface. This condition was verified by alpha particle backscattering. A stand-alone STM head, having a singlecrystal diamond tip, was used in conjunction with a Digital Instruments Nanoscope Ilia controller to generate the 13 μm long microploughs. The vertical ploughing force was measured using a Mettler AE130 semi-microbalance.
After generating the microploughs and measuring their geometry with an AFM, some of the microploughs were cross sectioned for TEM observation.
Scanning Kelvin Force and Capacitance Microscopy Applications
Authors: Kline RJ , Richards JF , Russell PE 
Published: July 2020

Abstract
Scanning Probe Microscopy (SPM) is being developed as a possible solution to the problems inherent with analyzing the nanometer scale electronic properties of ULSI integrated circuits. Scanning Kelvin Probe Microscopy (SKPM) and Scanning Capacitance Microscopy (SCM) are both being developed to provide two dimensional dopant profiles of semiconductor devices. SKPM can also determine surface potentials, work functions, dielectric properties, and capacitance.
SKPM is based on the concept of Kelvin probe oscillating capacitor work function measurements. The small capacitance area of the SKPM tip and the high resistance of the system produce difficulties in monitoring and minimizing the current in the system. SKPM solves this problem by utilizing the force monitoring capability of the SPM to minimize the Kelvin force instead of the current. An AC voltage applied to the cantilever produces a DC force and AC forces at the AC frequency and the first harmonic of the AC frequency.
Mapping the Organic and Inorganic Components of Normal and Osteoporotic Bone Using Nexafs.
Authors: Buckley C J , Khaleque N , Bellamy SJ , Dermody G , Robins M , Zhang X 
Published: July 2020

Abstract
Ultra-thin unstained sections of femoral neck bone from normal and ovariectomised mice were imaged in a scanning transmission x-ray microscope. The images were formed using soft x-ray energies at the calcium L and carbon K edges. The aim of the study was to quantitatively map the calcium, protein and embedding medium in normal and ovariectomised (osteoporotic) mice to compare the quantity and distribution of mineral (via calcium), collagen (via protein) and hydrated content (via embedding medium substitution).
A set of seven images were taken of both the normal and ovariectomised mouse sections. These images were processed using x-ray optical constants to produce mass thickness maps. The thickness of the sections from the normal mouse and ovariectomised mice were 205nm and 375nm respectively. The images show embedding medium, protein and calcium maps of near complete sections of the majority of the femoral neck at equivalent neck positions in the normal (la, 2a & 3a) and ovariectomised (lb, 2b & 3b) mouse bone sections.